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Drug Eluting Stents: On MIT’s Edelman Lab’s Contributions to Vascular Biology and its Pioneering Research on DES

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Drug Eluting Stents: On MIT‘s Edelman Lab’s Contributions to Vascular Biology and its Pioneering Research on DES

Author: Larry H Bernstein, MD, FACP

and

Curator: Aviva Lev-Ari, PhD, RN
http://PharmaceuticalIntelligence.com/2013/04/25/Contributions
-to-vascular-biology/

This is the first of a three part series on the evolution of vascular biology and the studies of the effects of biomaterials in vascular reconstruction and on drug delivery, which has embraced a collaboration of cardiologists at Harvard Medical School , Affiliated Hospitals, and MIT, requiring cardiovascular scientists at the PhD and MD level, physicists, and computational biologists working in concert, and an exploration of the depth of the contributions by a distinguished physician, scientist, and thinker.

The first part – Vascular Biology and Disease – will cover the advances in the research on

vascular biology,
signaling pathways,
drug diffusion across the endothelium and
the interactions with the underlying muscularis (media),
with additional considerations for type 2 diabetes mellitus.

The second part – Stents and Drug Delivery – will cover the

purposes,
properties and
evolution of stent technology with
the acquired knowledge of the pharmacodynamics of drug interactions and drug distribution.

The third part – Problems and Promise of Biomaterials Technology – will cover the shortcomings of the cardiovascular devices, and opportunities for improvement

Vascular Biology and Cardiovascular Disease

Early work on endothelial injury and drug release principles

The insertion of a catheter for the administration of heparin is not an innocuous procedure. Heparin is infused to block coagulation, lowering the risk of a dangerous

clot formation and
dissemination.

It was shown experimentally that the continuous infusion of heparin

suppresses smooth muscle proliferation after endothelial injury. It may lead to
hemorrhage as a primary effect.

The anticoagulant property of heparin was removed by chemical modification without loss of the anti-proliferative effect.

In this study, MIT researches placed ethylene-vinyl acetate copolymer matrices containing standard and modified heparin adjacent to rat carotid arteries at the time of balloon deendothelialization.

Matrix delivery of both heparin compounds effectively diminished this proliferation in comparison to controls without producing systemic anticoagulation or side effects.

This mode of therapy appeared more effective than administering the agents by either

intravenous pumps or

heparin/polymer matrices placed in a subcutaneous site distant from the injured carotid artery

This indicated that the site of placement at the site of injury is a factor in the microenvironment, and is a preference for avoiding restenosis after angioplasty and other interventions.

This raised the question of why the proliferation of vascular muscle occurs in the first place.  Edelman, Nugent and Karnovsky (1) showed that the proliferation required first the denudation of vascular surface endothelium. This exposed the underlayer to the effect of basic fibroblast growth factor, which stimulates mitogenesis of the exposed cell, explained by the endothelium as a barrier from circulating bFGF.

To answer this question, they compared the effect of

125I-labelled bFGF intravenously given with perivascular controlled bFGF release.
Polymeric controlled release devices delivered bFGF to the extravascular space without transendothelial transport.  Deposition within the blood vessel wall was rapidly distributed circumferentially and was substantially greater than that observed following intravenous injection.

The amount of bFGF deposited in arteries adjacent to the release devices was 40 times that deposited in similar arteries in animals who received a single intravenous bolus of bFGF.

The presence of intimal hyperplasia increased deposition of perivascularly released bFGF 2.4-fold but decreased the deposition of intravenously injected bFGF by 67%.

bFGF was 5- to 30-fold more abundant in solid organs after intravenous injection than it was following perivascular release, and
bFGF deposition was greatest in the kidney, liver, and spleen and was substantially lower in the heart and lung.

This result indicated that vascular deposition of bFGF is independent of endothelium, and

bFGF delivery is effectively perivascular. (2)

Drug activity studies have to be done in well controlled and representative conditions.  Edelsman’s Lab researchers studied the

dose response of injured arteries to exogenous heparin in vivo by providing steady and predictable arterial levels of drug.
Controlled-release devices were fabricated to direct heparin uniformly and at a steady rate to the adventitial surface of balloon-injured rat carotid arteries.

Researchers predicted the distribution of heparin throughout the arterial wall using computational simulations and correlated these concentrations with the biologic response of the tissues.

Researchers determined from this process that an in vivo arterial concentration of 0.3 mg/ml of heparin is required to maximallyinhibit intimal hyperplasia after injury.

This estimation of the required tissue concentration of a drug is

independent of the route of administration and
applies to all forms of drug release.

In this way the Team was able to

evaluate the potential of widely disparate forms of drug release and, to finally
create some rigorous criteria by which to guide the development of particular delivery strategies for local diseases. (3)

Chiefly, the following three effects:

(1) Effect of controlled adventitial heparin delivery on smooth muscle cell proliferation following endothelial injury. ER Edelman, DH Adams, and MJ Karnovsky. PNAS May 1990; 87: 3773-3777. 

(2) Perivascular and intravenous administration of basic fibroblast growth factor: Vascular and solid organ deposition. ER Edelman, MA Nugent, and MJ Karnovsky. PNAS Feb 1993; 90: 1513-1517. 

(3) Tissue concentration of heparin, not administered dose, correlates with the biological response of injured arteries in vivo. MA Lovich and ER Edelman. PNAS Sep 1999; 96: 11111–11116.

Vascular Injury and Repair

Perlecan is a heparin-sulfate proteoglycan that might be critical for regulation of vascular repair by inhibiting the binding and mitogenic activity of basic fibroblast growth factor-2 (bFGF-2) in vascular smooth muscle cells .

The Team generated

Clones of endothelial cells expressing an antisense vector targeting domain III of perlecan. The transfected cells produced significantly less perlecan than parent cells, and they had reduced bFGF in vascular smooth muscle cells.
Endothelial cells were seeded onto three-dimensional polymeric matrices and implanted adjacent to porcine carotid arteries subjected to deep injury.
The parent endothelial cells prevented thrombosis, but perlecan deficient cells were ineffective.

The ability of endothelial cells to inhibit intimal hyperplasia, however, was only in part suppressed by perlecan. The differential regulation by perlecan of these aspects of vascular repair may clarify why control of clinical clot formation does not lead to full control of intimal hyperplasia.

The use of genetically modified tissue engineered cells provides a new approach for dissecting the role of specific factors within the blood vessel wall.(1) Successful implementation of local arterial drug delivery requires transmural distribution of drug. The physicochemical properties of the applied compound govern its transport and tissue binding.

Hydrophilic compounds are cleared rapidly.
Hydrophobic drugs bind to fixed tissue elements, potentially prolonging tissue residence and biological effect.

Local vascular drug delivery provides

elevated concentrations of drug in the target tissue while
minimizing systemic side effects.

To better characterize local pharmacokinetics the Team examined the arterial transport of locally applied dextran and dextran derivatives in vivo.

Using a two-compartment pharmacokinetic model to correct

The measured transmural flux of these compounds for systemic
Redistribution and elimination as delivered from a photo-polymerizable hydrogel.
The diffusivities and the transendothelial permeabilities were strongly dependent on molecular weight and charge
For neutral dextrans, the diffusive resistance increased with molecular weightapproximately 4.1-fold between the molecular weights of 10 and 282 kDa.
Endothelial resistance increased 28-fold over the same molecular weight range.
The effective medial diffusive resistance was unaffected by cationic charge as such molecules moved identically to neutral compounds, but increased approximately 40% when dextrans were negatively charged.

Transendothelial resistance was 20-fold lower for the cationic dextrans, and 11-fold higher for the anionic dextrans, when both were compared to neutral counterparts.

These results suggest that, while

low molecular weight drugs will rapidly traverse the arterial wall with the endothelium posing a minimal barrier,

the reverse is true for high molecular weight agents.

The deposition and distribution of locally released vascular therapeutic compounds might be predicted based upon chemical properties, such as molecular weight and charge. (2)

Paclitaxel is hydrophobic and has therapeutic potential against proliferative vascular disease.  The favorable preclinical data with this compound may, in part, result from preferential tissue binding.  The complexity of Paclitaxel pharmacokinetics required in-depth investigation if this drug is to reach its full clinical potential in proliferative vascular diseases.

Equilibrium distribution of Paclitaxel reveals partitioning above and beyond perfusate concentration and a spatial gradient of drug across the arterial wall.

The effective diffusivity (Deff) was estimated from the Paclitaxel distribution data to

facilitate comparison of transport of Paclitaxel through arterial parenchyma with that of other vasoactive agents and to
characterize the disparity between endovascular and perivascular application of drug.

This transport parameter described the motion of drug in tissues given an applied concentration gradient and includes, in addition to diffusion,

the impact of steric hindrance within the arterial interstitium;
nonspecific binding to arterial elements; and, in the preparation used here,
convective effects from the applied transmural pressure gradient.

At all times, the effective diffusivity for endovascular delivery exceeded that of perivascular delivery. The arterial transport of Paclitaxel was quantified through application ex vivo and measurement of the subsequent transmural distribution.

Arterial Paclitaxel deposition at equilibrium varied across the arterial wall.
Permeation into the wall increased with time, from 15 minutes to 4 hours, and
varied with the origin of delivery.

In contrast to hydrophilic compounds, the concentration in tissue exceeded the applied concentration and the rate of transport was markedly slower. Furthermore, endovascular and perivascular Paclitaxel application led to differences in deposition across the blood vessel wall.

This leads to a conclusion that Paclitaxel interacts with arterial tissue elements as it moves under the forces of

diffusion and
convection and
can establish substantial partitioning and spatial gradients across the tissue. (3)

Endovascular drug-eluting stents have changed the practice of cardiovascular vascularization, and yet it is unclear how they so dramatically reduce restenosis

We don’t know how to distinguish between the different formulations available.  Researchers are now questioning whether individual properties of different drugs beyond lipid avidity effect arterial transport and distribution.

In bovine internal carotid segments, tissue-loading profiles for

Hydrophobic Paclitaxel and Rapamycin are indistinguishable, reaching load steady state after 2 days.
Hydrophilic dextran reaches equilibrium in hours.

Paclitaxel and Rapamycin bind to the artery at 30–40 times bulk concentration, and bind to specific tissue elements.

Transmural drug distribution profiles are markedly different for the two compounds.

Rapamycin binds specifically to FKBP12 binding protein and it distributes evenly through the artery,
Paclitaxel binds specifically to microtubules, and remains primarily in the subintimal space.

The binding of Rapamycin and Paclitaxel to specific intracellular proteins plays an essential role in

determining arterial transport and distribution and in
distinguishing one compound from another.

These results offer further insight into the

mechanism of local drug delivery and the
specific use of existing drug-eluting stent formulations. (4)

The Role of Amyloid beta (A) in Creation of Vascular Toxic Plaque

Amyloid beta (A) is a peptide family produced and deposited in neurons and endothelial cells (EC). It is found at subnanomolar concentrations in the plasma of healthy individuals.  Simple conformational changes produce a form of A-beta , A-beta 42, which creates toxic plaque in the brains of Alzheimer’s patients.

Oxidative stress induced blood brain barrier degeneration has been proposed as a key factor for A-beta 42 toxicity.

This cannot account for lack of injury from the same peptide in healthy tissues. Researchers hypothesized that cell state mediates A-beta’s effect.  They examined the viability in the presence of A-beta secreted from transfected Chinese hamster ovary cells (CHO) of

aortic Endothelial Cells (EC),
vascular smooth muscle cells (SMC) and
epithelial cells (EPI) in different states

A-beta was more toxic to all cell types when they were subconfluent.  Subconfluent EC sprouted and SMC and EPI were inhibited by A-beta. Confluent EC were virtually resistant to A-beta and suppressed A-beta production by A-beta +CHO.

Products of subconfluent EC overcame this resistant state, stimulating the production and toxicity of A-beta 42. Confluent EC overgrew >35% beyond their quiescent state in the presence of A-beta conditioned in media from subconfluent EC.

These findings imply that A-beta 42 may well be even more cytotoxic to cells in injured or growth states and potentially explain the variable and potent effects of this protein.

One may now need to consider tissue and cell state in addition to local concentration of and exposure duration to A-beta.

The specific interactions of A-beta and EC in a state-dependent fashion may help understand further the common and divergent forms of vascular and cerebral toxicity of A-beta and the spectrum of AD. (5)

(1) Perlecan is required to inhibit thrombosis after deep vascular injury and contributes to endothelial cell-mediated inhibition of intimal hyperplasia. MA Nugent, HM Nugent, RV Iozzoi, K Sanchack, and ER Edelman. PNAS Jun 2000; 97(12): 6722-6727 

(2) Correlation of transarterial transport of various dextrans with their physicochemical properties. O Elmalak, MA Lovich, E Edelman. Biomaterials 2000; 21: 2263-2272 

(3) Arterial Paclitaxel Distribution and Deposition. CJ Creel, MA Lovich, ER Edelman. Circ Res. 2000;86:879-884 

(4) Specific binding to intracellular proteins determines arterial transport properties for rapamycin and Paclitaxel. AD Levin, N Vukmirovic, Chao-Wei Hwang, and ER Edelman. PNAS Jun 2004; 101(25): 9463–9467. www.pnas.org/cgi/doi/10.1073/pnas.0400918101 

(5) Amyloid beta toxicity dependent upon endothelial cell state. M Balcells, JS Wallins, ER Edelman. Neuroscience Letters 441 (2008) 319–322

Endothelial Damage as an Inflammatory State

Autoimmunity may drive vascular disease through anti-endothelial cell (EC) antibodies. This raises a question about whether an increased morbidity of cardiovascular diseases in concert with systemic illnesses may involve these antibodies.

Matrix-embedded ECs act as powerful regulators of vascular repair accompanied by significant reduction in expected systemic and local inflammation.

The Lab researchers compared the immune response against free and matrix-embedded ECs in naive mice and mice with heightened EC immune reactivity. Mice were presensitized to EC with repeated subcutaneous injections of saline-suspended porcine EC (PAE) (5*10^5 cells).

On day 42, both naive mice (controls) and mice with heightened EC immune reactivity received 5*10^5 matrix-embedded or free PAEs. Circulating PAE-specific antibodies and effector T-cells were analyzed 90 days after implantation for –

PAE-specific antibody-titers,
frequency of CD4+-effector cells, and
xenoreactive splenocytes

These were 2- to 4-fold lower (P<0.0001) when naıve mice were injected with matrix-embedded instead of saline-suspended PAEs.

Though basal levels of circulating antibodies were significantly elevated after serial PAE injections (2210+341 mean fluorescence intensity, day 42) and almost doubled again 90 days after injection of a fourth set of free PAEs, antibody levels declined by half in recipients of matrix-embedded PAEs at day 42 (P<0.0001), as did levels of CD4+-effector cells and xenoreactive splenocytes.

A significant immune response to implantation of free PAE is elicited in naıve mice, that is even more pronounced in mice with pre-developed anti-endothelial immunity.

Matrix-embedding protects xenogeneic ECs against immune reaction in naive mice and in mice with heightened immune reactivity.

Matrix-embedded EC might offer a promising approach for treatment of advanced cardiovascular disease. (1)

Researchers examined the molecular mechanisms through which

mechanical force and hypertension modulate

endothelial cell regulation of vascular homeostasis.

Exposure to mechanical strain increased the paracrine inhibition of vascular smooth muscle cells (VSMCs) by endothelial cells.

Mechanical strain stimulated the production by endothelial cells of perlecan and heparan-sulfate glycosaminoglycans. By inhibiting the expression of perlecan with an antisense vector researchers demonstrated that perlecan was essential to the strain-mediated effects on endothelial cell growth control.

Mechanical regulation of perlecan expression in endothelial cells was

governed by a mechano-transduction pathway
requiring transforming growth factor (TGF-β) signaling and
intracellular signaling through the ERK pathway.

Immunohistochemical staining of the aortae of spontaneously hypertensive rats demonstrated strong correlations between

endothelial TGF-β,
phosphorylated signaling intermediates, and
arterial thickening.

Studies on ex vivo arteries exposed to varying levels of pressure demonstrated that

ERK and TGF-beta signaling were required for pressure-induced upregulation of endothelial HSPG.

The Team’s findings suggest a novel feedback control mechanism in which

net arterial remodeling to hemodynamic forces is controlled by a dynamic interplay between growth stimulatory signals from vSMCs and
growth inhibitory signals from endothelial cells. (2)

Heparan-sulfate proteoglycans (HSPGs) are potent regulators of vascular remodeling and repair.  The major enzyme capable of degrading HSPGs is heparanase, which led us to examine the role of heparanase in controlling

arterial structure,
mechanics, and
remodeling.

In vitro studies suggested heparanase expression in endothelial cells serves as a negative regulator of endothelial inhibition of vascular smooth muscle cell (vSMC) proliferation.

ECs inhibit vSMC proliferation through the interplay between

growth stimulatory signals from vSMCs and
growth inhibitory signals from ECs.

This would be expected if ECs had HSPGs that are degraded by heparanase. Arterial structure and remodeling to injury is modified by heparanase expression. Transgenic mice overexpressing heparanase had

increased arterial thickness,
cellular density, and
mechanical compliance.

Endovascular stenting studies in Zucker rats demonstrated increased heparanase expression in the neointima of obese, hyperlipidemic rats in comparison to lean rats.

The extent of heparanase expression within the neointima strongly correlated with the neointimal thickness following injury. To test the effects of heparanase overexpression on arterial repair, researchers developed a novel murine model of stent injury using small diameter self-expanding stents.

Using this model, researchers found that increased

neointimal formation and
macrophage recruitment occurs in transgenic mice overexpressing heparanase.
Taken together, these results support a role for heparanase in the regulation of arterial structure, mechanics, and repair. (3)

The first host–donor reaction in transplantation occurs at the blood–tissue interface. When the primary component of the implant (donor) is the endothelial cells, it incites an immunologic reaction. Injections of free endothelial cell implants elicit a profound major histocompatibility complex (MHC) II dominated immune response.

Endothelial cells embedded within three-dimensional matrices behave like quiescent endothelial cells.

Perivascular implants of such embedded ECs cells are the most potent inhibitor of intimal hyperplasia and thrombosis following controlled vascular injury, but without any immune reactivity.

Allo- and even exenogenic endothelial cells evoke no significant humoral or cellular immune response in immune-competent hosts when embedded within matrices.  Moreover, endothelial implants are immune-modulatory, reducing the extent of the memory response to previous free cell implants.

Attenuated immunogenicity results in muted activation of adaptive and innate immune cells. These findings point toward a pivotal role of matrix–cell-interconnectivity for

the cellular immune phenotype and might therefore assist in the design of
extracellular matrix components for successful tissue engineering. (4)

Because changes in subendothelial matrix composition are associated with alterations of the endothelial immune phenotype, researchers sought to understand if

cytokine-induced NF-κB activity and
downstream effects depend on substrate adherence of endothelial cells (EC).

The team compared the upstream

phosphorylation cascade,
activation of NF-ĸβ, and
expression/secretion

of downstream effects of EC grown on tissue culture polystyrene plates (TCPS) with EC embedded within collagen-based matrices (MEEC).

Adhesion of natural killer (NK) cells was quantified in vitro and in vivo.

NF-κβ subunit p65 nuclear levels were significantly lower and
p50 significantly higher in cytokine-stimulated MEEC than in EC-TCPS.

Despite similar surface expression of TNF-α receptors, MEEC had significantly decreased secretion and expression of IL-6, IL-8, MCP-1, VCAM-1, and ICAM-1.

Attenuated fractalkine expression and secretion in MEEC (two to threefold lower than in EC-TCPS; p < 0.0002) correlated with 3.7-fold lower NK cell adhesion to EC (6,335 ± 420 vs. 1,735 ± 135 cpm; p < 0.0002).

Furthermore, NK cell infiltration into sites of EC implantation in vivo was significantly reduced when EC were embedded within matrix.

Matrix embedding enables control of EC substratum interaction.

This in turn regulates chemokine and surface molecule expression and secretion, in particular – of those compounds within NF-κβ pathways,

chemoattraction of NK cells,
local inflammation, and
tissue repair. (5)

Monocyte recruitment and interaction with the endothelium is imperative to vascular recovery.

Tie2 plays a key role in endothelial health and vascular remodeling. Researchers studied monocyte-mediated Tie2/angiopoietin signaling following interaction of primary monocytes with endothelial cells and its role in endothelial cell survival.

The direct interaction of primary monocytes with subconfluent endothelial cells

resulted in transient secretion of angiopoietin-1 from monocytes and

the activation of endothelial Tie2. This effect was abolished by preactivation of monocytes with tumor necrosis factor-α (TNFα).

Although primary monocytes contained high levels of

both angiopoietin 1 and 2,
endothelial cells contained primarily angiopoietin 2.

Seeding of monocytes on serum-starved endothelial cells reduced caspase-3 activity by 46+5.1%, and 52+5.8% after TNFα treatment, and it decreased single-stranded DNA levels by 41+4.2% and 40+ 3.5%, respectively.

This protective effect of monocytes on endothelial cells was reversed by Tie2 silencing with specific short interfering RNA.

The antiapoptotic effect of monocytes was further supported by the

activation of cell survival signaling pathways involving phosphatidylinositol 3-kinase,
STAT3, and
AKT.

Monocytes and endothelial cells form a unique Tie2/angiopoietin-1 signaling system that affects endothelial cell survival and may play critical a role in vascular remodeling and homeostasis. (6)

(1) Cell–Matrix Contact Prevents Recognition and Damage of Endothelial Cells in States of Heightened Immunity. H Methe, ER Edelman. Circulation. 2006;114[suppl I]:I-233–I-238. http://www.circulationaha.org/DOI/10.1161/CIRCULATIONAHA.105.000687

(2) Endothelial Cells Provide Feedback Control for Vascular Remodeling Through a Mechanosensitive Autocrine TGFβ Signaling Pathway. AB Baker, DS Ettenson, M Jonas, MA Nugent, RV Iozzo, ER Edelman. Circ. Res. 2008;103;289-297 http://dx.doi.org/10.1161/CIRCRESAHA.108.179465 http://circres.ahajournals.org/cgi/content/full/103/3/289

(3) Heparanase Alters Arterial Structure, Mechanics, and Repair Following Endovascular Stenting in Mice. AB Baker, A Groothuis, M Jonas, DS Ettenson…ER Edelman. Circ. Res. 2009;104;380-387; http://dx.doi.org/10.1161/CIRCRESAHA.108.180695 http://circres.ahajournals.org/cgi/content/full/104/3/380

(4) The effect of three-dimensional matrix-embedding of endothelial cells on the humoral and cellular immune response. H Methe, S Hess, ER Edelman. Seminars in Immunology 20 (2008) 117–122. http://dx.doi.org/10.1016/j.smim.2007.12.005

(5) NF-kB Activity in Endothelial Cells Is Modulated by Cell Substratum Inter-actions and Influences Chemokine-Mediated Adhesion of Natural Killer Cells. S Hess, H Methe, Jong-Oh Kim, ER Edelman. Cell Transplantation 2009; 18: 261–273 

(6) Primary Monocytes Regulate Endothelial Cell Survival Through Secretion of Angiopoietin-1 and Activation of Endothelial Tie2. SY Schubert, A Benarroch, J Monter-Solans and ER Edelman. Arterioscler Thromb Vasc Biol 2011;31;870-875 http://dx.doi.org/10.1161/ATVBAHA.110.218255

Neointimal Formation, Shear Stress, and Remodelling with Reference to Diabetes

Innate immunity is of major importance in vascular repair. The present study evaluated whether

systemic and transient depletion of monocytes and macrophages with
liposome-encapsulated bisphosphonates inhibits experimental in-stent neointimal formation.

The Experiment

Rabbits fed on a hypercholesterolemic diet underwent bilateral iliac artery balloon denudation and stent deployment.

Liposomal alendronate (3 or 6 mg/kg) was given concurrently with stenting.

Monocyte counts were reduced by 90% 24 to 48 hours aftera single injection of liposomal alendronate, returning to basal levels at 6 days.

This treatment significantly reduced

intimal area at 28 days, from 3.88+0.93 to 2.08+0.58 and 2.16 +0.62 mm2.
Lumen area was increased from 2.87+0.44 to 3.57+0.65 and 3.45+0.58 mm2, and

arterial stenosis was reduced from 58 11% to 37 8% and 38 7% in controls, in rabbits treated with 3 mg/kg, and with 6 mg/kg, respectively (mean+SD, n=8 rabbits/group, P< 0.01 for all 3 parameters).

No drug-related adverse effects were observed. Reduction in neointimal formation was associated with

reduced arterial macrophage infiltration and proliferation at 6 days and with an
equal reduction in intimal macrophage and smooth muscle cell content at 28 days after injury.

Conversely, drug regimens ineffective in reducing monocyte levels did not inhibit neointimal formation. Researchers have shown that a

single liposomal bisphosphonates injection concurrent with injury reduces in-stent neointimal formation and
arterial stenosis in hypercholesterolemic rabbits, accompanied by systemic transient depletion of monocytes and macrophages. (1)

Diabetes and insulin resistance are associated with increased disease risk and poor outcomes from cardiovascular interventions.

Even drug-eluting stents exhibit reduced efficacy in patients with diabetes. Researchers reported the first study of vascular response to stent injury in insulin-resistant and diabetic animal models.

Endovascular stents were expanded in the aortae of

obese insulin-resistant and
type 2 diabetic Zucker rats,
in streptozotocin-induced type 1 diabetic Sprague-Dawley rats, and
in matched controls.

Insulin-resistant rats developed thicker neointima (0.46+0.08 versus 0.37+0.06 mm2, P 0.05), with decreased lumen area (2.95+0.26 versus 3.29+0.15 mm2, P 0.03) 14 days after stenting compared with controls, but without increased vascular inflammation (tissue macrophages).

Insulin-resistant and diabetic rat vessels did exhibit markedly altered signaling pathway activation 1 and 2 weeks after stenting, with up to a 98% increase in p-ERK (anti-phospho ERK) and a 54% reduction in p-Akt (anti-phospho Akt) stained cells. Western blotting confirmed a profound effect of insulin resistance and diabetes on Akt and ERK signaling in stented segments. p-ERK/p-Akt ratio in stented segments uniquely correlated with neointimal response (R2 = 0.888, P< 0.04) , but not in lean controls.

Transfemoral aortic stenting in rats provides insight into vascular responses in insulin resistance and diabetes.

Shifts in ERK and Akt signaling related to insulin resistance may reflect altered tissue repair in diabetes accompanied by a

shift in metabolic : proliferative balance.

These findings may help explain the increased vascular morbidity in diabetes and suggest specific therapies for patients with insulin resistance and diabetes. (2)

Researchers investigated the role of Valsartan (V) alone or in combination with Simvastatin (S) on coronary atherosclerosis and vascular remodeling, and tested the hypothesis that V or V/S attenuate the pro-inflammatory effect of low endothelial shear stress (ESS).

Twenty-four diabetic, hyperlipidemic swine were allocated into Early (n = 12) and Late (n=12) groups. Diabetic swine in each group were treated with Placebo (n=4), V (n = 4) and V/S (n = 4) and followed for 8 weeks in the Early group and 30 weeks in the Late group.

Blood pressure, serum cholesterol and glucose were similar across the treatment subgroups. ESS was calculated in plaque-free subsegments of interest (n = 109) in the Late group at week 23. Coronary arteries of this group were harvested at week 30, and the subsegments of interest were identified, and analyzed histopathologically.

Intravascular geometrically correct 3-dimensional reconstruction of the coronary arteries of 12 swine was performed 23 weeks after initiation of diabetes mellitus and a hyperlipidemic diet. Local endothelial shear stress was calculated

in plaque-free subsegments of interest (n=142) with computational fluid dynamics, and
the coronary arteries (n=31) were harvested and the same subsegments were identified at 30 weeks.

V alone or with S

reduced the severity of inflammation in high-risk plaques. Both regimens attenuated the severity of enzymatic degradation of the arterial wall, reducing the severity of expansive remodeling.
attenuated the pro-inflammatory effect of low ESS. V alone or with S
exerts a beneficial effect of reducing and stabilizing high-risk plaque characteristics independent of a blood pressure- and lipid-lowering effect. (3)

This study tested the hypothesis that low endothelial shear stress augments the

expression of matrix-degrading proteases, promoting the
formation of thin-capped atheromata.

Researchers assessed the messenger RNA and protein expression, and elastolytic activity of selected elastases and their endogenous inhibitors.

Subsegments with low endothelial shear stress at week 23 showed

reduced endothelial coverage,
enhanced lipid accumulation, and
intense infiltration of activated inflammatory cells at week 30.

These lesions showed increased expression of messenger RNAs encoding

matrix metalloproteinase-2, -9, and -12, and cathepsins K and S
relative to their endogenous inhibitors and
increased elastolytic activity.

Expression of these enzymes correlated positively with the severity of internal elastic lamina fragmentation.

Thin-capped atheromata in regions with

lower preceding endothelial shear stress had
reduced endothelial coverage,
intense lipid and inflammatory cell accumulation,
enhanced messenger RNA expression and
elastolytic activity of MMPs and cathepsins with
severe internal elastic lamina fragmentation.

Low endothelial shear stress induces endothelial discontinuity and

accumulation of activated inflammatory cells, thereby
augmenting the expression and activity of elastases in the intima and
shifting the balance with their inhibitors toward matrix breakdown.

Team’s results provide new insight into the mechanisms of regional formation of plaques with thin fibrous caps. (4)

Elevated CRP levels predict increased incidence of cardiovascular events and poor outcomes following interventions. There is the suggestion that CRP is also a mediator of vascular injury.

Transgenic mice carrying the human CRP gene (CRPtg) are predisposed to arterial thrombosis post-injury.

Researchers examined whether CRP similarly modulates the proliferative and hyperplastic phases of vascular repair in CRPtg when thrombosis is controlled with daily aspirin and heparin at the time of trans-femoral arterial wire-injury.

Complete thrombotic arterial occlusion at 28 days was comparable for wild-type and CRPtg mice (14 and 19%, respectively). Neointimal area at 28d was 2.5 fold lower in CRPtg (4190±3134 m2, n = 12) compared to wild-types (10,157±8890 m2, n = 11, p < 0.05).

Likewise, neointimal/media area ratio was 1.10±0.87 in wild-types and 0.45±0.24 in CRPtg (p < 0.05).

Seven days post-injury, cellular proliferation and apoptotic cell number in the intima were both less pronounced in CRPtg than wild-type.
No differences were seen in leukocyte infiltration or endothelial coverage. CRPtg mice had significantly reduced p38 MAPK signaling pathway activation following injury.

The pro-thrombotic phenotype of CRPtg mice was suppressed by aspirin/heparin, revealing CRP’s influence on neointimal growth after trans-femoral arterial wire-injury.

Signaling pathway activation,
cellular proliferation, and
neointimal formation

were all reduced in CRPtg following vascular injury.  Increasingly the Team was aware of CRP multipotent effects.  Once considered only a risk factor, and recently a harmful agent, CRP is a far more complex regulator of vascular biology. (5)

(1) Liposomal Alendronate Inhibits Systemic Innate Immunity and Reduces In-Stent Neointimal Hyperplasia in Rabbits. HD Danenberg, G Golomb, A Groothuis, J Gao…, ER Edelman. Circulation. 2003;108:2798-2804 

(2) Vascular Neointimal Formation and Signaling Pathway Activation in Response to Stent Injury in Insulin-Resistant and Diabetic Animals. M Jonas, ER Edelman, A Groothuis, AB Baker, P Seifert, C Rogers. Circ. Res. 2005;97;725-733. http://dx.doi.org/10.1161/01.RES.0000183730.52908.C6 http://circres.ahajournals.org/cgi/content/full/97/7/725

(3) Attenuation of inflammation and expansive remodeling by Valsartan alone or in combination with Simvastatin in high-risk coronary atherosclerotic plaques. YS Chatzizisis, M Jonas, R Beigel, AU Coskun… ER Edelman, CL Feldman, PH Stone. Atherosclerosis 203 (2009) 387–394 

(4) Augmented Expression and Activity of Extracellular Matrix-Degrading Enzymes in Regions of Low Endothelial Shear Stress Colocalize With Coronary Atheromata With Thin Fibrous Caps in Pigs. YS Chatzizisis, AB Baker, GK Sukhova,…P Libby, CL Feldman, ER Edelman, PH Stone Circulation 2011;123;621-630 http://dx.doi.org/10.1161/CIRCULATIONAHA.110.970038 http://circ.ahajournals.org/cgi/content/full/123/6/621 

(5) Neointimal formation is reduced after arterial injury in human crp transgenic mice HD Danenberg, E Grad, RV Swaminathan, Z Chenc,…ER Edelman Atherosclerosis 201 (2008) 85–91

A Rattle Bag of Science and the Art of Translation

Science Translational Medicine – A rattle bag of science and the art of translation E. R. Edelman, G. A. FitzGerald. Sci.Transl. Med. 3, 104ed3 (2011). http://dx.doi.org/10.1126/scitranslmed.3002131

Elazer R. Edelman is the Thomas D. and Virginia W. Cabot Professor of Health Sciences and Technology at MIT, Professor of Medicine at Harvard Medical School, a coronary care unit cardiologist at the Brigham and Women’s Hospital, and Director of the Harvard-MIT Biomedical Engineering Center. E-mail: ere@mit.edu

Garret A. FitzGerald is the McNeil Professor in Translational Medicine and Therapeutics, Chair of the Department of Pharmacology, and Director of the Institute for Translational Medicine & Therapeutics, University of Pennsylvania. E-mail: garret@upenn.edu

In 2011, the American Association for the Advancement of Science (AAAS) founded Science Translational Medicine (STM) to disseminate interdisciplinary science integrating basic and clinical research that defines and fosters new therapeutics, devices, and diagnostics.

Conceived and nourished under the creative vision of Elias Zerhouni and Katrina Kelner, the journal has attracted widespread attention. Now, as we assume the mantle of co-chief scientific advisors, we look back on the journal’s early accomplishments, restate our mission, and make clear the kinds of manuscripts we seek and accept for publication.

STM’s mission, as articulated by Elias and Katrina, was to

“promote human health by providing a forum for communication and cross-fertilization among basic, translational, and clinical research practitioners and trainees from all relevant established and emerging disciplines.”

This statement remains relevant and accurate today.  With this mission on our masthead, STM now receives ~25 manuscripts (full-length research articles) per week and publishes ~10% of them. Roughly half of the submissions are deemed inappropriate for the journal and are returned without review within 8 to 10 days of receipt.

Of those papers that undergo full peer review,

decisions to reject are made within 48 days and

the mean time to acceptance (including the revision period) is 125 days.

There is now an average wait of only 24 days between acceptance and publication.

Defining TRANSLATIONAL Medicine

In accord with the journal’s broad readership, the ideal manuscript meets five criteria: It (i) reports a discovery of translational relevance with high-impact potential; (ii) has a conceptual focus with interdisciplinary appeal; (iii) elucidates a biological mechanism; (iv) is innovative and novel; and (v) is presented in clear, broadly accessible language.  STM seeks to publish research that describes

how innovative concepts drive the creative biomedical science
that ultimately improves the quality of people’s lives—

This is the broadest of our journal’s criteria but is the one that sets us apart as well. Translational relevance does not require demonstration of benefit in humans but does require the evident potential to advance clinical medicine, thus impacting the direction of our culture and the welfare of our communities. Conceptual focus and mechanistic emphasis discriminate our papers from those that contain observational descriptions of technical findings for which value is restricted to a specific discipline.

However, innovation and novelty may apply to a fundamental scientific discovery or to the nature of its application and relevance to the translational process. Criteria enable the journal to consider versatile technological advances that apply new and creative thinking but may not necessarily offer fresh insights into biological mechanisms. Finally, while the subsequent additional efforts of the STM editorial staff are not to be discounted, the clarity of writing and coherence of argument presented within a submitted manuscript are likely to facilitate its progress through the challenge of peer review.

On Causes – Hippocrates, Aristotle, Robert Koch, and the Dread Pirate Roberts

Elazer R. Edelman Circulation 2001;104:2509-2512

The idea of risk factors for vascular disease has evolved

from a dichotomous to continuous hazard analysis and
from the consideration of a few factors to
mechanistic investigation of many interrelated risks.

However, confusion still abounds regarding issues of association and causation. Originally, the simple presence of

tobacco abuse, hypertension, and/or hypercholesterolemia were tallied, and
the cumulative score was predictive of subsequent coronary artery disease.

Since then, dose responses have been defined for these and other factors and it has been suggested that almost 300 factors place patients at risk; these factors include elevations in plasma homocysteine.  Recent studies shed interesting light on the mechanism of this potentially causal relationship, which was first noted in 1969.

Aside from putative effects on vessel wall dynamics, there is now direct evidence that homocysteine is atherogenic. Twenty-fold increases in plasma homocysteine achieved by dietary manipulation of apoE–/– mice increased aortic root lesion size 2-fold and produced a prolonged chronic inflammatory mural response accompanied by elevations in vascular cell adhesion molecule-1 (VCAM) and tumor necrosis factor-a (TNF-a).

In long term followup, homocysteine levels elevated by

dietary supplementation with methionine or homocysteine
promoted lesion size and plaque fibrosis in these
atherosclerosis-prone mice early in life, but without influencing ultimate plaque burden as the animals aged.

A number of mechanisms were proposed by which homocysteine achieved this effect, including

promotion of inflammation,
regulation of lipoprotein metabolism, and
modification of critical biochemical pathways and
metabolites including nitric oxide (NO).

See p 2569 In the present issue of Circulation,

Stühlinger et al 7 advance these mechanistic insights one critical step further by defining homocysteine’s effects at an enzymatic level.

The group led by Lentz published an association between levels of the

endogenous inhibitor of Nirtic Oxide synthase,
asymmetric dimethyl arginine (ADMA), and

homocysteine in cultured endothelial cells and in the serum of cynomolgus monkeys.

Such an association is interesting because the L-arginine–NO synthase pathway seems to be a critical component in the full range of endothelial cell biology and vascular dysfunction.

Stühlinger et al 7 now show that increased cultured endothelial cell elaboration of ADMA by homocysteine and its precursor L-methionine is associated with a dose-dependent impairment of the activity of endothelial dimethylarginine dimethylaminohydrolase (DDAH), the enzyme that degrades ADMA. Homocysteine directly inhibited DDAH activity in a cell-free system by targeting a critical sulfhydryl group on this enzyme.

Thus, one could envision that the balance of cardiovascular health and disease could well be determined by the ability of an intact Nirtic Oxide synthase system to overcome environmental, dietary, and even genetic factors.

In patients with altered enzymatic defense systems,

elevated homocysteine,
oxidized lipoproteins,
inflammation, and other
vasotoxins

may dominate even the most potent defense mechanisms. These studies raise a number of issues. Do we need to add to our list of established cardiovascular risk factors to accommodate new findings and associations? Is there a final common pathway for all risk factors or perhaps even a unified factor theory into which all potential risks can be grouped? And, as always, should we consider Nirtic Oxide at the core of this universality? Finally, should we change our focus altogether and speak not of risk factors but of

genetic predisposition,
extent of biochemical aberration, and
degree of physical damage?

Some would view these remarkable success stories and the repeated association of hyperhomocyst(e)inemia with coronary, cerebral, and peripheral vascular disease and simply advocate for increased folic acid intake for all.

Indeed, this intervention of negligible cost and

insignificant side effect is already partially in place;
many foods are fortified with folate to prevent congenital neural tube defects.

This reader considers the seminal work by Vernon Young and Yves Ingenbleek on the relationship between

S8 and regions distant from lava flows in Asia and Indian subcontinents,
where they have determined hyperhomocysteinemia and the consequence associated with:
veganism (not voluntary)
impaired methyl donor reactions and transsulfuration pathways (not corrected by B12, folate)
loss of lean body mass due to the constant relationship of S:N (insufficient from plant sources)

What happens, when we fail to continue to pursue causality,

the linkage of biological significance or scientific plausibility with
epidemiologically or statistically significant association?

In medicine, risk becomes the likelihood that people without a disease will acquire the disease through contact with factors thought to increase disease risk.

All of these risk factors are then, by nature, imprecise and nonspecific.  They are stochastic measures of what will happen to normal people who fall into particular measures of these parameters.

The daring may be willing to accept these risks, citing friend and foe who live well beyond or for far lesser times than anticipated by risk alone. Such concerns may well become moot if we can simultaneously identify patients at risk

by linking phenotype with genotype,
gene expression with protein elaboration, and
environmental exposures with the biochemical consequences and
direct anatomic aberrations they induce.

This kind of characterization may well replace a family history of arterial disease as a rough estimate of

genotype,

serum cholesterol as an indirect measure of the health of lipoprotein metabolism,
serum glucose as a crude determinant of the ravages of diabetes mellitus,
blood pressure measurement as a marker of long-standing endogenous exposure to altered flow, and
tobacco abuse as a maker of long-standing exposure to exogenous toxins.

Rather than identifying patients on the basis of their serum cholesterol, we will have a direct measure of their

LDL receptor number,
internalization rate,
macrophage content in the blood vessel wall,
metalloproteinase activity, etc.
insulin receptor metabolism,
oxidative state, and
glycated burden.
Serum glucose will similarly give way to these tests

Evaluating a new way to open clogged arteries: Computational model offers insight into mechanisms of drug-coated balloons.

A new study from MIT analyzes the potential usefulness of a new treatment that combines the benefits of angioplasty balloons and drug-releasing stents, but may pose fewer risks. With this new approach, a balloon is inflated in the artery for only a brief period, during which it releases a drug that prevents cells from accumulating and clogging the arteries over time.

While approved for limited use in Europe, these drug-coated balloons are still in development in the United States and have not received FDA approval. The MIT study, which models the behavior of the balloons, should help scientists optimize their performance and aid regulators in evaluating their effectiveness and safety.

“Until now, people who evaluate such technology could not distinguish hype from promise,” says Elazer Edelman, the Thomas D. and Virginia W. Cabot Professor of Health Sciences and Technology and senior author of the paper describing the study, which appeared online recently in the journal Circulation.

Lead author of the paper is Vijaya Kolachalama, a former MIT postdoc who is now a principal member of the technical staff at the Charles Stark Draper Laboratory.

Edelman’s lab is investigating a possible alternative to the current treatments: drug-coated balloons. “We’re trying to understand how and when this therapy could work and identify the conditions in which it may not,” Kolachalama says. “It has its merits; it has some disadvantages.”

Modeling drug release

The drug-coated balloons are delivered by a catheter and inflated at the narrowed artery for about 30 seconds, sometimes longer. During that time, the balloon coating, containing a drug such as Zotarolimus, is released from the balloon. The properties of the coating allow the drug to be absorbed in the body’s tissues. Once the drug is released, the balloon is removed.

In their new study, Kolachalama, Edelman and colleagues set out to rigorously characterize the properties of the drug-coated balloons. After performing experiments in tissue grown in the lab and in pigs, they developed a computer model that explains the dynamics of drug release and distribution. They found that factors such as the size of the balloon, the duration of delivery time, and the composition of the drug coating all influence how long the drug stays at the injury site and how effectively it clears the arteries.

One significant finding is that when the drug is released, some of it sticks to the lining of the blood vessels. Over time, that drug is slowly released back into the tissue, which explains why the drug’s effects last much longer than the initial 30-second release period.

“This is the first time we can explain the reasons why drug-coated balloons can work,” Kolachalama says. “The study also offers areas where people can consider thinking about optimizing drug transfer and delivery.”

http://circ.ahajournals.org/content/127/20/2047.short
http://www.mit.edu/people/vbk/Circulation_2013.pdf
http://www.sciencedaily.com/…13/05/130521121513.ht…
Circulation, 2013; 127 (20): 2047 – 2055
http://dx.doi.org/10.1161/CIRCULATIONAHA.113.002051;

Conclusion

MIT’s Edelman’s Lab conducted the pioneering work in Vascular biology, animal models of drug eluting stents and was at the forefront of Empirical Molecular Cardiology in its studies in vascular physiology, biology and biomaterials for medical devices.

Related articles

MUC1* Ligand, NM23-H1, Is a Novel Growth Factor That Maintains Human Stem Cells in a More Naïve State (plosone.org)

Mass. General team develops implantable, bioengineered rat kidney (eurekalert.org)

Suppression of JAK2/STAT3 Signaling Reduces End-to-End Arterial Anastomosis Induced Cell Proliferation in Common Carotid Arteries of Rats (plosone.org)

Blood Vessel Function and Breathing Control Adversely Affected by Cutting Back on Sleep (medindia.net)

miRNA Biogenesis Enzyme Drosha Is Required for Vascular Smooth Muscle Cell Survival (plosone.org)

Cell-Permeable Peptide Shows Promise For Controlling Cardiovascular Disease (medicalnewstoday.com)

The Heart Revolution By Kilmer McCully, Martha McCully

HarperCollinsPublishers, 1969

http://books.google.com/books?id=iYLbuZFxEt8C&pg=PR20&dq=New+York+Times+homocysteine+and+Cholesterol&hl=en&sa=X&ei=_0F7UfDRA8zB4APozIHQAQ&ved=0CEMQ6AEwAg

Nitric Oxide and it’s impact on Cardiothoracic Surgery

Posted in Bio Instrumentation in Experimental Life Sciences Research, BioSimilars, Cardiac & Vascular Repair Tools Subsegment, Cardiovascular Pharmacogenomics, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Exec Compensation in the Cardiac & Vascular Repair Tools Subsegment, Nitric Oxide in Health and Disease, Regulated Clinical Trials: Design, Methods, Components and IRB related issues, Stents & Tools, tagged arterial disease, Atherosclerosis, cardiothoracic surgery, cardiovascular, Clinical Trials, endothelial, hyperplasia, Inhaled NO, L-arginine, local delivery, neointimal hyperplasia, nitric oxide, NO, restenosis, Stent, systemic delivery, vascular, vascular smooth muscle cells (VSMC) on December 15, 2012| 9 Comments »

Nitric Oxide and it’s impact on Cardiothoracic Surgery

Author, curator: Tilda Barliya PhD

In the past few weeks we’ve had extensive in-depth series about nitric oxide (NO) and it’s role in renal function and donors in renal disorders, coagulation, endothelium and hemostasis. This inspired this new post regarding the impact of NO on cardiothoratic surgery. You can read and follow up on these posts here: http://pharmaceuticalintelligence.com/category/nitric-oxide-in-health-and-disease/

Atherosclerosis in the form of peripheral arterial disease (PAD) affects approximately eight million Americans, which includes 12 to 20% of individuals over the age of 65. Approximately 20% of patients with PAD have typical symptoms of lower extremity claudication, rest pain, ulceration, or gangrene, and one-third have atypical exertional symptoms.Persons with PAD have impaired function and quality of life even if they do not report symptoms and experience a decline in lower extremity function over time. Cardiovascular disease is the major cause of death in patients with intermittent claudication; the annual rate of cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes) is 5 to 7%. Thus, PAD represents a significant source of morbidity and mortality. (1) (http://www.medscape.com/viewarticle/569812).

Several options exist for treating atherosclerotic lesions, including:

percutaneous transluminal angioplasty with and without stenting,
endarterectomy
bypass grafting

Unfortunately, patency rates for each of these procedures continue to be suboptimal secondary to the development of neointimal hyperplasia. A universal feature of all vascular surgical procedures is the removal of or damage to the endothelial cell monolayer that occurs whether the procedure performed is endovascular or open. This endothelial damage leads to a decreased or absent production of nitric oxide (NO) at the site of injury.

he relationship between NO and the cardiovascular system has proven to be a landmark discovery, and the scientists credited for its discovery were awarded the Nobel Prize in Medicine in 1998. Since its discovery, NO has proven to be one of the most important molecules in vascular homeostasis. In fact, the term endothelial dysfunction has now become synonymous with the reduced biologic activity of NO.

NO produced by endothelial cells has been shown to have many beneficial effects on the vasculature.

As described above,

NO stimulates vascular smooth muscle cells (VSMC) relaxation, which leads to vessel vasodilatation.
NO has opposite beneficial affects on endothelial cells compared with VSMCs.
Whereas NO stimulates endothelial cell proliferation and prevents endothelial cell apoptosis, it inhibits VSMC growth and migration and stimulates VSMC apoptosis.
NO also has many thromboresistant properties, such as inhibition of platelet aggregation, adhesion, and activation; inhibition of leukocyte adhesion and migration; and inhibition of matrix formation

As stated before, the endothelial cell monolayer is often removed or damaged during the time of vascular procedures, which leads to a local decrease in the production of NO. It is now understood that this loss of local NO synthesis by endothelial cells at the site of vascular injury is one of the inciting events that allows platelet aggregation, inflammatory cell infiltration, and VSMC proliferation and migration to occur in excess, which, taken together, leads to neointimal hyperplasia.

Reendothelialization of the injured artery can restore proper function to the artery and potentially halt the restenotic process. Many studies have attempted to improve the patency of bypass grafts and stents by coating them with endothelial cells in the hope that this would restore the thromboresistant nature of native blood vessels.

Unfortunately, although it has been possible to coat these devices with endothelial cells, these cells do not behave like normal endothelial cells and their NO production is often diminished or absent. Because the vasoprotective properties of endothelial cells are largely carried out by NO alone, investigators are engaged in research to improve the bioavailability of NO at the site of vascular injury in an attempt to reduce the risk of thrombosis and restenosis after successful revascularization. The overall goal of using a NO-based approach is to reproduce the same thromboresistive moiety observed with normal NO production.

Why of delivering NO to the injured site:

Systemic delivery
Local delivery

Systemic Delivery

One simple mechanism by which to deliver NO to the body is via inhalational therapy. Inhaled NO has been used clinically in the past to selectively reduce pulmonary vascular resistance in patients with pulmonary hypertension, as well as a potential therapy for patients with acute respiratory distress syndrome. Because the gas is delivered only to the pulmonary system and has a very short half-life, it was thought that there would be no systemic effects of the drug. Subsequently, studies in the mid- to late 1990s suggested that inhaled NO had beneficial antiplatelet and antileukocyte properties without adverse systemic side effects (2,3)

To test if inhaled NO had any beneficial systemic properties specifically on the vasculature, Lee and colleagues evaluated the effect of inhaled NO on neointimal hyperplasia in rats undergoing carotid balloon injury, Unfortunately, the treatment was required for the full 2 weeks to see any difference between the treatment and the control group, thereby limiting its clinical utility.

Despite some of the early animal studies, investigations with healthy human volunteers failed to reproduce these findings.I t was speculated that despite the obvious effects of inhaled NO on the pulmonary vasculature, systemic bioavailability could not be reliably achieved because of the immediate binding and depletion of NO by hemoglobin as soon as it entered the systemic circulation.

Hamon and colleagues tested the ability of orally supplementing l-arginine (2.25%), the precursor to NO, in the drinking water of rabbits to reduce the formation of neointimal hyperplasia after injuring the iliac arteries with a balloon. This amount of l-arginine is approximately sixfold higher than normal daily intake. When the arteries were studied 4 weeks after injury, the l-arginine-fed group exhibited less neointimal hyperplasia and greater acetylcholine-induced relaxation compared with the control animals. The authors speculated that the improved outcomes were due to increased bioavailability of NO secondary to the l-arginine-supplemented diets. To test the ability of this supplemented diet to reduce neointimal hyperplasia in a vein bypass graft model, Davies and colleagues fed rabbits l-arginine (2.25%) 7 days prior to and 28 days after common carotid vein bypass grafts. A 51% decrease in the formation of neointimal hyperplasia was demonstrated in the l-arginine-fed groups, and their vein grafts exhibited preserved NO-mediated relaxation.

Despite some of the positive findings in animals, similar studies in humans have failed to show any benefit with l-arginine supplementation. Shiraki and colleagues studied the effects of short-term high-dose l-arginine on restenosis after PTCA. Thirty-four patients undergoing cardiac catheterization and PTCA for angina pectoris received 500 mg of l-arginine administered through the cardiac catheter immediately prior to PTCA and 30 g per day of l-arginine administered via the peripheral vein for 5 days after PTCA. No significant statistical differences in restenosis were observed between the two groups (34% vs 44%). The authors speculated that the lack of effect was secondary to the fact that although the levels of l-arginine in the plasma increased significantly, NO and cyclic guanosine monophosphate (cGMP) did not. (4)

Table 1. Comparison of Different Nitric Oxide Donor Drugs Currently Used for Clinical or Research Purposes
Drug	Mechanism of NO Release	Unique Properties
Diazeniumdiolates	Spontaneous when in contact with physiologic fluidsNO release follows first-order kinetics	Stable as solidsVarious reliable half-lives depending on the structure of the nucleophile it is attached to
Diazeniumdiolates		Nitrosamines can form as by-products
S-Nitrosothiols	Copper ion-mediated decomposition	Stable as a solid
	Direct reaction with ascorbate	Must be protected from light
	Homeolytic cleavage by light	Present in circulating blood
	Homeolytic cleavage by light	Potential for unlimited NO release
Sydnonimines	Requires enzymatic cleavage by liver esterases to form active metabolite	Stable as a solidMust be protected from light
Sydnonimines	Requires molecular oxygen as an electron acceptor	Requires alkaline pHReleases superoxide as a by-product, which may have negative effects
l-Arginine	Substrate for NOS genes	Stable as a solid
		Ease of administration
		Dependent on presence of NOS for NO production
Sodium nitroprusside	Requires a one-electron reduction to release NO	Stable as a solid
	Requires a one-electron reduction to release NO	Must be protected from light
	Light can induce NO release	Must be given intravenously
	Light can induce NO release	Releases cyanide as a by-product
Organic nitrates	Either by enzymatic cleavage or nonenzymatic bioactivation with sulfhydryl or thiol groups	Stable as a solid
		Must be protected from light
		Ease of administration
		Development of tolerance limits efficacy
NO-releasing aspirin	Require enzymatic cleavage to break the covalent bond between the aspirin and the NO moiety	Stable as a solid
		Ease of administration
		Inherent benefits of aspirin also
		Does not affect systemic blood pressure

Despite the ease of administration, the reliability of drug delivery, and the relative safety of these NO-donating drugs, there are limitations associated with systemic administration. One such limitation is that NO is rapidly inactivated by hemoglobin in the circulating blood, resulting in limited bioavailability. Furthermore, in attempts to increase the amount of drug delivered to obtain the desired clinical effect, unwanted systemic circulatory effects (eg, vasodilation) and unwanted hemostatic effects (eg, bleeding) often preclude administration of biologically effective doses of NO.

Because NO produces systemic side effects, lower doses of NO have been used in many of the human studies. One of the reasons for the differences observed between the animal studies and the human studies was the 10- to 50-fold lower doses of drugs used in the human studies compared with the animal studies. Thus, local delivery of NO may achieve improved results.

Local Delivery

The local delivery of drugs allows for the administration of the maximally effective dose of a drug without the unwanted systemic side effects. Because the target vessels are easily accessible during most vascular procedures, a local pharmacologic approach to administer a drug during the intervention can be easily performed.

Suzuki and colleagues performed a prospective, randomized, single-center clinical trial. (7)

The study population consisted of patients with symptomatic ischemic heart disease who were undergoing coronary artery stent placement. After stent deployment, l-arginine (600 mg/6 mL) or saline (6 mL) was locally delivered via a catheter over 15 minutes. The patients were followed with serial angiography and intravascular ultrasonography to assess for neointimal thickness for up to 6 months. The authors found that in the l-arginine-treated groups, there was slightly less neointimal volume, but this was not statistically significant.

Because it was not known if the addition of l-arginine actually translated to increased NO production, several studies have focused on the addition of NO donors directly to the site of injury.However, Critics of some of the highlighted animal studies point out that the evaluation of neointimal hyperplasia was performed radiographically, which could be subjectively biased. Furthermore, infusing the drug through a catheter for an extended period of time during the procedure to achieve an effect is not clinically feasible. Because of this, other studies have aimed to develop a clinically applicable approach to deliver NO locally to the site of injury.

Hydrogels
Vascular grafts
Gene therapy

represents another method by which to locally increase the level of NO at the site of vascular injury, tested in different multiple creative animal models. Thought, most of this studies shown great preliminary results, only the gene therapy moved forward into randomized clinical trial in humans using gene therapy to reduce neointimal hyperplasia.

In December 2000, the Recombinant DNA Advisory Committee at the National Institutes of Health voted unanimously to proceed with the first phase of clinical evaluation of iNOS lipoplex-mediated gene transfer, called REGENT-1: Restenosis Gene Therapy Trial. (8). The primary objective of this multicenter, prospective, single-blind, dose escalation study was to obtain safety and tolerability information of iNOS-lipoplex gene therapy for reducing restenosis following coronary angioplasty. As of 2002, 27 patients had been enrolled overseas and the process had been determined to be safe. To date, no results have been published as it appears that this trial lost its funding and closed. On April 5, 2002, a notification was issued that the trial had been closed without enrolling any individuals in the United States.

Unfortunately, despite the promising findings shown with NOS therapy, the field of gene therapy has been mottled by two widely known complications. One case occurred as the result of administering a large viral load that led to the death of a patient. In addition, in France, there were at least two cases of malignancy following retroviral gene therapy. (9)

Summary

Atherosclerosis in the form of coronary artery disease and peripheral vascular disease continues to be a major source of morbidity and mortality. Unfortunately, the procedures and materials that are currently used to alleviate these disease states are temporary at best because of the inevitable injury to the native endothelium and the subsequent impairment of NO release. Since the discovery of NO and its role in vascular biology, a main focus in vascular research has been to create novel mechanisms to use NO to combat neointimal hyperplasia. To date, numerous animal studies have restored NO production to the vasculature and have shown that this inhibits neointimal hyperplasia, improves patency rates, and is safe to the animal. Clinical studies using these novel NO-releasing compounds in humans are on the horizon.

Ref:

1. Daniel A. Popowich, Vinit Varu, Melina R. Kibbe. Nitric Oxide: What a Vascular Surgeon Needs to Know. Vascular. 2007;15(6):324-335. (http://www.medscape.com/viewarticle/569812).

2. Gries A, Bode C, Peter K, et al. Inhaled nitric oxide inhibits human platelet aggregation, P-selectin expression, and fibrinogen binding in vitro and in vivo Circulation 1998;97:1481-7.

3. Lee JS, Adrie C, Jacob HJ, et al. Chronic inhalation of nitric oxide inhibits neointimal formation after balloon-induced arterial injury Circ Res 1996;78:337-42.

4. Shiraki T, Takamura T, Kajiyama A, et al. Effect of short-term administration of high dose l-arginine on restenosis after percutaneous transluminal coronary angioplasty J Cardiol 2004;44:13-20.

5. David A. Fullerton, MD, Robert C. McIntyre, Jr, MD. Inhaled Nitric Oxide: Therapeutic Applications in Cardiothoracic Surgery. Ann Thorac Surg 1996;61:1856-1864. http://ats.ctsnetjournals.org/cgi/content/abstract/61/6/1856

6. Owen I.Miller,Swee Fong Tang, Anthony Keech,Nicholas B.Pigott, Elaine Beller and David S. Celemajer. Inhaled nitric oxide and prevention of pulmonary hypertension after congenital heart surgery: a randomised double-blind study. The Lancet,2000:356; 9240 Pages 1464 – 1469, http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(00)02869-5/abstract

7. Suzuki T, Hayase M, Hibi K, et al. Effect of local delivery of l-arginine on in-stent restenosis in humans Am J Cardiol 2002;89:363-7.

8. von der Leyen HE, Chew N. Nitric oxide synthase gene transfer and treatment of restenosis: from bench to bedside Eur J Clin Pharmacol 2006;62:83-89

9. Barbato JE, Tzeng E. iNOS gene transfer for graft disease Trends Cardiovasc Med 2004;14:267-72.

10. E. Matevossian, A. Novotny, C. Knebel, T. Brill, M. Werner, I. Sinicina, M. Kriner, M. Stangl, S. Thorban, and N. Hüser. The Effect of Selective Inhibition of Inducible Nitric Oxide Synthase on Cytochrome P450 After Liver Transplantation in a Rat Model. Transplantation Proceedings 2008, 40, 983–985. http://211.144.68.84:9998/91keshi/Public/File/29/40-4/pdf/1-s2.0-S0041134508004181-main.pdf

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Endothelial Dysfunction, Diminished Availability of cEPCs, Increasing CVD Risk for Macrovascular Disease – Therapeutic Potential of cEPCs

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Endothelial Dysfunction, Diminished Availability of cEPCs, Increasing CVD Risk — Macrovascular Disease – Therapeutic Potential of cEPCs

Author and Investigator Initiated Study: Aviva Lev-Ari, PhD, RN

In normal conditions, the vascular endothelium produces and secretes substances that modulate vascular tone and protect the vessel wall from inflammatory cell infiltration, thrombus formation, and vascular smooth muscle cell proliferation (Rubanyi, 1993). Pathologic conditions such as hyperlipidemia, hyperglycemia, and hypertension impair the ability of the vascular endothelium to produce vasodilatory and anti-adhesion moieties and increase the production of vasoconstrictor, proadhesion, and pro-thrombotic molecules, leading to elevated vascular tone, enhanced cell adhesion, proliferation of media smooth muscle cells, and propensity toward thrombosis (Drexler & Hornig, 1999),(Endemann & Schiffrin, 2004). Endothelial cell loss and turnover are accelerated in the presence of hemodynamic and biochemical alterations and are a prominent feature of vascular injury resulting from percutaneous coronary intervention (Bennett & O’Sullivan, 2001).

The loss of endothelial function and integrity sets in motion the cascade of events that lead to atherosclerosis and restenosis after percutaneous revascularization (Ross, 1999),(Dzau et al., 2002). Processes of mobilization, growth, differentiation, recruitment, homing, replication and migration characterize cEPCs from the initial cell division of stem cells to cell apoptosis. What are the factors influencing cEPC mobilization, growth, differentiation, recruitment, mobilization, homing, replication and migration?

Physiological Factors

Chemokines

SCF-1, G-CSF, GM-CSF

Effect on cEPCs: recruitment, mobilization (Takahashi et al., 1999), (Kong et al., 2004a), (Kocher et al. 2001), (Shi et al., 1998), (Cho et al., 2003),(Orlic et al., 2001),(Bhattacharya et al., 2000), (Shi et al, 2002)

SDF-1

Effect on cEPCs: recruitment, mobilization, homing (Yamaguchi et al., 2003),(Powell et al., 2005),(Askari et al., 2003), (Hiasa et al., 2004),(George et al., 2003),(George et al., 2004),(Massa et al., 2005)

Cytokines / Growth Factors

FGF, VEGF, PIGF

Effect on cEPCs: mobilization, differentiation (Kalka et al., 2000a),(Ashara et al., 1997),(Kalka et al., 2000b)

Angiopoietin, PDGF

Effect on cEPCs: differentiation

Hormones

Erythropoietin

Effect on cEPCs: mobilization, replication (Heeschen et al., 2003), (George, et. al., 2005).

Estrogen

Effect on cEPCs: mobilization (Strehlow et al., 2003), (Imanishi et al., 2005)

Signaling molecules

NO, Akt

Effect on cEPCs: mobilization, differentiation(Aicher et al., 2003).

Pharmacological Factors

3-HMC-CoA Inhibitors (statins)

Effect on cEPCs: mobilization, migration, homing (Werner et al., 2003),(Vasa et al., 2001a),(Walter et al., 2002),(Dimmeler et al., 2001),

(Llevadot et al., 2001),(Spyridopoulos et al., 2004)

PPAR-gamma Agonists

Effect on cEPCs: mobilization, differentiation (Verma & Szmitko, 2006), (Andrew et al., 2004)

Physical Factors

Exercise, hypoxia

Effect on cEPCs: mobilization (Laufs et al., 2003),(Kleinman et al., 2005),(Goon et al., 2006)

Pathological Factors

Coronary artery disease (CAD)

Effect on cEPCs: mobilization, homing (Kalka et al., 2000a),(Vasa et al., 2001b),(Heeschen et al., 2004)

Acute MI

Effect on cEPCs: mobilization, homing (Shintani et al., 2001),(Valgimigli et al., 2004),(Massa et al., 2005)

Peripheral limb ischemia

Effect on cEPCs: mobilization, homing (Takahashi et al., 1999),(Iwaguro et al., 2002),(Asahara et al., 1997),(Kalka et al., 2000b)

Vascular injury and inflammation

Effect on cEPCs: mobilization, homing (Ross, 1999),( Losordo et al., 2003), (Dimmeler & Zeiher, 2004),(Werner et al., 2003),(Verna et al, 2004).

EPC transplantation has been shown to induce new vessel formation in ischemic myocardium and hind limb (Kalka et al., 2000c),(Kawamoto et al, 2001),(Kocher, 2001) and to accelerate re-endothelialization of injured vessels and prosthetic vascular grafts in humans and in various animal models (Kocher, 2001),(Griese et al., 2003) demonstrating their therapeutic potential as a cell-based strategy for rescue and repair of ischemic tissues and injured blood vessels. Furthermore, EPCs are amenable to genetic manipulation, underscoring their usefulness as vectors for local delivery of therapeutic genes (Griese et al., 2003),(Kong et al., 2004b), (Iwaguro, 2002)

Clinical Frontiers and Therapeutic Applications of cEPCs

Angiogenesis
Neovascularization of Artherosclerotic Plaque
Risk Factors impairing Collateral Development
Inhibitory Effects of Hypercholesterolemia
Bone Marrow Cells: Supporting cells in vascular growth processes
Inverse Relations: cEPCs and Risk of Macrovascular Events
New Stenting Technology:

Stents eluting Nitric Oxide (Verma and Marsden, 2005)
Stents coated with antiboby specific (anti-CD34) to the EPCs antigen cell (Chadwick, 2006),(Aoki et al., 2005)
EPC-covered intravascular stents deployed for prevention of stent thrombosis and restenosis as well as for rapid formation of normal tissue architecture (Shirota et al., 2003).

Table 1: Alterations in number and function of cEPCs Disease Characterization and Suitability for ElectEagle an Endogenous Augmentation Method for cEPCs number (not for cEPCs function)

Disease Type (Dzau et al., 2005)	Number of cEPCs	Function of cEPCs	References	Disease Suitability for Endogenous Augmentation of cEPCs
Myocardial
CAD	down	down	(Kalka et al., 2000a),(Shintani et al., 2001),(Vasa et al., 2000b),(Hill et al., 2003),(Heeschen et al., 2004)	yes
CHF	down	down	(Valgimigli et al.,2004),(Massa et al., 2005)	yes
Unstable angina	down	unknown	(George et al., 2004)	yes
MI	up	down	(Massa et al., 2005)	No
Vascular
Atherosclerosis	down	down	(Vasa et al., 2001b),(Heeschen, 2004)(Lusis, 2000)	yes
Acute Vascular injury and inflammation	up	unknown	(Fuujiyama et al.,2003)(Werner et al., 2003),(Walter et al., 2002),(Strehlow et al., 2003),(Shi et al., 1998),(Gill et al., 2001), (Chu et al., 2003)	No
PeripheralLimb ischemia	up	unknown	(Takahashi et al.,1999),(Iwaguro et al., 2002),(Asahara et al., 1997),(Asahara et al., 1999),(Kalka et al., 2000b)(Segal at al., 2006)	No
Transplantarteriopathy	down	unknown	(Simper at al., 2003)	Yes
In-stentrestenosis	down	unknown	(George et al., 2003)	yes
Hypertension	unknown	unknown		No
Hyperlipidemia	down	down	(Rauscher et al., 2003)	yes
Diabetes	down	down	(Loomans et al.,2004),(Tepper et al., 2002)	yes
Renal Failure
Hemodialysis	down	down	(Choi et al., 2004)	yes

Source: original table created by Lev-Ari, A.

Based on Table 1, above, Lev-Ari, A. concluded that four Cardiovascualr diseases are NOT candidates for cEPCs therapeutic treatment

List of Disease unsuitable for ElectEagle an Endogenous Augmentation Method for cEPCs includes:

Myocardial infarction
Acute Vascular injury and inflammation
Peripheral Limb ischemia
Hypertension

Table 2: Therapeutic Angiogenesis Effects achieved by Cell-Based Therapy: Donor, Human; Recipient, Autologous;

Diagnosis, Myocardial Infarction

Therapeutic Effect	Measured Effect	Method of Delivery	Type and Source of Cells	References
EjectionFruction	Up (Stamm et al.,2003) (Assmus et al., 2002), (Britten et al., 2003), (Schachinger et al., 2004), (Wollert et al., 2004) (Fernandez-Aviles et al., 2004), (Kang et al., 2004)	Infarct border (Stamm et al., 2003)	CD133 (Stamm et al., 2003), BM (Stamm et al., 2003)	(Stamm et al., 2003)
Collateral flow (SPECT)	Up (Stamm et al., 2003)
Infarct size	Down (Strauer et al., 2002)	Intracoronary Balloon Catheter (Strauer et al., 2002)	BM (Strauer et al., 2002)	(Strauer et al., 2002)
Wall motion	Up (Strauer et al., 2002)
Contractility	Up (Assmus et al., 2002), (Britten et al., 2003), (Schachinger et al., 2004), (Wollert et al., 2004)	Intracoronary Balloon Catheter (Assmus et al., 2002), (Britten et al., 2003), (Schachinger et al., 2004), (Wollert et al., 2004)	BM PB MNC (Assmus et al., 2002), (Britten et al., 2003), (Schachinger et al., 2004), (Wollert et al., 2004)	(Assmus et al., 2002),(Britten et al., 2003),(Schachinger et al., 2004), (Wollert et al., 2004)
Myocardial perfusion	Up (Assmus et al., 2002), (Britten et al., 2003), (Schachinger et al., 2004), (Wollert et al., 2004)
Remodeling	Down (Assmus et al., 2002), (Britten et al., 2003), (Schachinger et al., 2004), (Wollert et al., 2004)
LV wall thickness	Up (Fernandez-Aviles et al., 2004)	Intracoronary w/PCA (Fernandez-Aviles et al., 2004)	CD34⁺ CD117⁺ AC133⁺	(Fernandez-Aviles et al., 2004)
End-systolic (ESV) volume	Down (Fernandez-Aviles et al., 2004)
Exercise time	Up (Kang et al., 2004)	Intracoronary G-CSF	CD34⁺	(Kang et al., 2004)

Table 3:

Therapeutic Angiogenesis Effects achieved by Cell-Based Therapy: Donor, Human; Recipient, Autologous;

Diagnosis, Myocardial Ischemia – Unstable Ischemia

Therapeutic Effect	Measured Effect	Method of Delivery	Type and Source of Cells	References
Ejection Fruction	Up (Perin et al., 2003), (Tse et al., 2003)	Transendocardial with NOGA mapping	MNCs (Perin et al., 2003), (Tse et al., 2003) BM (Perin et al., 2003), (Tse et al., 2003)	(Perin et al., 2003), (Tse et al., 2003)
Anginal episodes	Down (Perin et al., 2003), (Tse et al., 2003)
Wall thickening	Up (Perin et al., 2003), (Tse et al., 2003)
Wall motion	Up (Perin et al., 2003), (Tse et al., 2003)

REFERENCES

Aicher A, Heeschen C, Mildner-Rihm C, Urbich C, Ihling C, Technau- Ihling K, Zeiher AM, Dimmeler S, (2003). Essential role of endothelial nitric oxide synthase for mobilization of stem cell and progenitor cells. Nat Med., 9:1370-1376.

Anderson T. (1999). Assessment of treatment of endothelial dysfunction. J Am Coll of Cardiology, 34: 631- 8.

Andrew C. Li, Binder, CJ, Gutierrez, A, Brown, KK, Plotkin, CR, Pattison, JW, Valledor, AF, Davis, RA, Willson, TM, Witztum, JL, Palinski, W, Glass, CK. (2004). Differential inhibition of macrophage foam-cell formation and atherosclerosis in mice by PPAR-alpha, Beta/delta, and gamma. J. Clin. Invest. 114:1564-1576

http://www.jci.org/articles/view/18730

Aoki, J., Serruys, P.W., van Beusekom, H., Ong, A.T., McFadden, E.P., Sianos, G., et al. (2005). Endothelial progenitor cell capture by stents coated with antibody against CD34: the HEALING-FIM (Healthy Endothelial Accelerated Lining Inhibits Neointimal Growth-First In Man) Registry. J Am Coll Cardiol 45 (10), 1574–1579.

Asahara T, Murohara T, Sullivan A, Silver M, van der Zee R, Li T, Witzenbichler B, Schatterman G, and Isner JM (1997). Isolation of putative progenitor endothelial cells for angiogenesis. Science 275: 964–967.

Asahara T, Masuda H, Takahashi T, Kalka C, Pastore C, Silver M, Kearne M, Magner M, Isner JM. (1999). Bone marrow origin of endothelial progenitor cells responsible for postnatal vasculogenesis in physiological and pathological neovascularization. Circ Res. 85:221–228.

Askari AT, Unzek S, Popovic ZB, Goldman CK, Forudi F, Kiedrowski M, Rovner A, Ellis SG, Thomas JD, DiCorleto PE, Topol EJ, Penn MS.(2003). Effect of stromal cell-derived factor 1 on stem cell homing and tissue regeneration in ischemic cardiomyopathy. Lancet, 362:697–703.

Assmus B, Schachlinger V, Teupe C, Britten M, Lehmann R, Dobert N, Grunwald F, Aicher A, Urbich C, Martin H, Hoelzer D, Dimmeler S, Zeiher AM, (2002). Transplantation of progenitor cells and regeneration enhancement in acute myocardial infarction (TOPCARE-AMI). Circulation, 106:3009 –3017

Bennett MR, O’Sullivan MO (2001). Mechanisms of angioplasty and stent restenosis: implications for design of rational therapy. Pharmacol Ther., 91:149 –166.

Ben-Shoshan, J and George, J. (2006). Endothelial progenitor cells as therapeutic vectors in cardiovascular disorders: from experimental models to human trials Pharmacology Therapeutics (impact factor: 8.9). 08/2007; 115(1):25-36.

Bhattacharya V, Shi Q, Ishida A, Sauvage LR, Hammond WP, Wu MH.(2000). Administration of granulocyte colony-stimulating factor enhances endothelialization and microvessel formation in small caliber synthetic vascular grafts. J Vasc Surg., 32:116 –123.

Bonetti PO, et al. (2002). Reactive hyperemia peripheral arterial tonometry, a novel non-invasive index of peripheral vascular function, is attenuated in patients with coronary endothelial dysfunction. Circulation, 106:Suppl II:579.

Bonetti PO, et al. (2003). Enhanced external counterpulsation improves endothelial function in patients with symptomatic coronary artery disease. J Am Coll of Cardiology, 41:1761-8.

Britten MB, Abolmaali ND, Assmus B, Lehman R, Honold J, Schmitt J, Vogl TJ, Martin H, Schachinger V, Dimmeler S, Zeiher AM, (2003). Infarct remodeling after intracoronary progenitor cell treatment in patients with acute myocardial infarction (TOPCARE-AMI): mechanistic insights from serial contrast-enhanced magnetic resonance imaging. Circulation, 108:2212–2218.

Bypass Angioplasty Revascularization Investigation in Type 2 Diabetics (BARI 2D) ClinicalTrials.gov Identifier: NCT00006305, 2000-2007

http://www.nejm.org/doi/full/10.1056/NEJMoa0805796

Caplice NM, Bunch TJ, Stalboerger PG, Wang S, Simper D, Miller DV, Russell SJ, Litzow MR, Edwards WD. (2003). Smooth muscle cells in human coronary atherosclerosis can originate from cells administered at marrow transplantation. Proc Natl Acad Sci U S A. 100: 4754–4759.

Chadwick , D.(2006) OrbusNeich’s Genous Bioengineered R-stent . Cath Lab Digest, 14 (1), 20-26

Cho H-J, Kim H-S, Lee M-M, Kim D-H, Yang H-J, Hur J, Hwang K-K, Oh S, Choi Y-J, Chae I-H, Oh, B-H, Choi Y-S, Walsh K, Park Y-B. (2003). Mobilized endothelial progenitor cells by granulocyte-macrophage colony-stimulating factor accelerate reendothelialization and reduce vascular inflammation after intravascular radiation. Circulation, 108:2918 –2925.

Choi J-H, Kim KL, Huh W, Kim B, Byun J, Suh W, Sung J, Jeon E-S, Oh H-Y, Kim D-K, (2004). Decreased number and impaired angiogenic function of endothelial progenitors in patients with chronic renal failure. Arterioscler Thromb Vasc Biol.,24:1246 –1252.

Cinamon G, Shinder V, Alon R (2001) Shear forces promote lymphocyte migration across vascular endothelium bearing apical chemokines. Nature Immunology, 2:515

Dimmeler S, Aicher A, Vasa M, Mildner-Rihm C, Adler K, Tiemann M, Rutten H, Fichtlscherer S, Martin H, Zeiher AM, (2001). HMG-CoA reductase inhibitors (statins) increase endothelial progenitor cells via the PI3-kinase/Akt pathway. J Clin Invest., 108:391–397.

Dimmeler S and Zeiher AM, (2004). Vascular repair by circulating endothelial progenitor cells: the missing link in atherosclerosis. J Mol Med. 82:671– 677.

Drexler H and Hornig B, (1999). Endothelial dysfunction in human disease. J Mol Cell Cardiol., 31:51– 60.

Dzau VJ, Braun-Dullaeus RC, Sedding DG. (2002). Vascular proliferation and atherosclerosis: new perspectives and therapeutic strategies. Nat Med., 8:1249 –1256.

Dzau, VJ, Gnecchi, M, Pachori, AS, Morello F, Melo, LG.(2005).Therapeutic Potential of Endothelial Progenitor Cells in Cardiovascular Diseases.Hypertension,246:7-18.

Edelberg JM, Tang L, Hattori K, Lyden D, Rafii. (2002). Young adult bone marrow-derived endothelial precursor cells restore aging-impaired cardiac angiogenic function. Circ Res., 90:e89–e93.

Endemann DH and Schiffrin EL, (2004). Endothelial dysfunction. J Am Soc Nephrol., 15:1983–1992.

Fadini, G, Avogaro A, Agostini C. (2004), Unambiguous Definition of Endothelial Progenitor Cells. Electronic Letter to the Editor of Heart in reference to article by Eizawa, T, Ikeda U, et al. Decreasing in circulating endothelial progenitor cells in patients with stable CAD, Heart, 2004; 90: 685-686,

http://heart.bmjjournals.com/cgi/eletters/90/6/685#310 retrieved on 6/26/2006Link not found 5/1/2013

Fernandez-Aviles F, San Roman JA, Garcıa-Frade J, Fernandez ME, Penarrubia MJ, de la Fuente Luis, Gomez-Bueno M, Cantalapiedra A, Fernandez J, Gutierrez O, Sanchez PL, Hernandez C, Sanz R, Garcıa- Sancho J, Sa´nchez A, (2004). Experimental and clinical regenerative capability of human bone marrow cells after myocardial infarction. Circ Res., 95:742–748.

Folsom, A.R. Chambless, L.E. Ballantyne, C.M. Coresh, J. Heiss, G. Wu, K.K. Boerwinkle, E. Mosley, T.H. Sorlie, P. Diao, G. Sharrett, A.R. (2006). An Assessment of Incremental Coronary Risk Prediction Using C-Reactive Protein and Other Novel Risk Markers – The Atherosclerosis Risk in Communities Study. Arch Intern. Med. 166, 1368-1373.

Fuujiyama S, Amano K, Uehira K, Yoshida N, Nishiwaki Y, Nozawa Y, Jin D, Takai S, Miyazaki M, Egashira K, Imada T, Iwasaka T, Matsubara H, (2003). Bone marrow monocyte lineage cells adhere on injured endothelium in a monocyte chemoattractant protein-1-dependent manner and accelerate reendothelialization as endothelial progenitor cells. Circ Res., 93:980-989.

George F, Brisson C, Poncelet P, Laurent JC, Massot O, Arnoux D, Ambrosi P, Klein-Soyer C, Cazenave JP, and Sampol J (1992). Rapid isolation of human endothelial cells from whole blood using S-Endo 1 monoclonal antibody coupled to immunomagnetic beads: demonstration of endothelial injury after angioplasty.Thromb Haemost, 67:147–153.

George J, Herz I, Goldstein E, Abashidze S, Deutch V, Finkelstein A, Michowitz Y, Miller H, Keren G.(2003). Number and adhesive properties of circulating endothelial progenitor cells in patients with in-stent restenosis. Arterioscler Thromb Vasc Biol., 23:e57– e60.

George J, Goldstein E, Abashidze S, Deutsch V, Shmilovich H, Finkelstein A, Herz I, Miller H, Keren G., (2004). Circulating endothelial progenitor cells in patients with unstable angina: association with systemic inflammation. Eur Heart J., 25:1003–1008.

George, J., Goldstein, E., Abashidze, S., Wexler, D., Hamed, S., Shmilovich, H., et al. (2005). Erythropoietin promotes endothelial progenitor cell proliferative and adhesive properties in a PI 3-kinase-dependent manner. Cardiovasc Res 68(2), 299-306.

George J, Shmilovich H, Deutsch V, Miller H, Keren G, Roth A. (2006). Comparative Analysis of Methods for Assessment of Circulating Endothelial Progenitor Cells, Tissue Engineering 12 (2) 331-335

Gerhard-Herman M, et al. (2002). Assessment of endothelial function (nitric oxide) at the tip of a finger. Circulation, 106:Suppl II:170.

Gill M, Dias S, Hattori K, Rivera ML, Hicklin D, Witte L, Girardi L, Yurt R, Himel H, Rafii S, (2001). Vascular trauma induces rapid but transient mobilization of VEGFR2/AC133 endothelial precursor cells. Circ Res., 88:167–174.

Goon, P.K.Y. Lip G.Y.H, Boos, CJ, Stonelake, PS, Blann, AD. (2006). Circulating Endothelial Cells, Endothelial Progenitor Cells, and Endothelial Microparticles in Cancer, Neoplasia, 8:79-88.

Griese DP, Ehsan A, Melo LG, Kong D, Zhang L, Mann MJ, Pratt RE, Mulligan RC, Dzau VJ, (2003). Isolation and transplantation of autologous circulating endothelial cells into denuded vessels and prosthetic grafts: implications for cell-based vascular therapy. Circulation, 108: 2710–2715.

Heeschen C, Aicher A, Lehmann R, Fichtlscherer S, Vasa M, Urbich C, Mildner-Rihm C, Martin H, Zeiher AM, Dimmeler, (2003). Erythropoietin is a potent physiological stimulus for endothelial progenitor cell mobilization. Blood, 102:1340 –1346.

Heeschen C, Lehman R, Honold J, Assmus B, Aicher A, Walter DH, Martin H, Zeiher AM, Dimmeler S. (2004). Profoundly reduced neovascularization capacity of bone marrow mononuclear cells derived from patients with chronic ischemic heart disease.Circulation, 109:1615–1622.

Heissig B, Hattori K, Dias S, Friedrich M, Ferris B, Hackett NR, Crystal RG, Besmer P, Lyden D, Moore MA, Werb Z, Rafii S., (2002). Recruitment of stem and progenitor cells from the bone marrow niche requires MMP-9 mediated release of kit-ligand. Cell;109: 625-637.

Hiasa K, Ishibashi M, Ohtani K, Inoue S, Zhao Q, Kitamoto S, Sata M, Ichiki T, Takeshita A, Egashira K. Gene transfer of stromal cell-derived factor 1 enhances ischemic vasculogenesis and angiogenesis via vascular endothelial growth factor/endothelial nitric oxide synthaserelated pathway: next generation chemokine therapy for therapeutic neovascularization. Circulation, 109:2454 –2461.

Hill JM, Zalos G, Halcox JPG, Schenke WH, Waclawin MA, Quyyumi A, Finkel T. (2003). Circulating endothelial progenitor cells, vascular function and cardiovascular risk. N Engl J Med., 348:593– 600.

Hillebrands J-L, Klatter FA, van DijK WD, Rozing J. (2003). Bone marrow does not contribute substantially to endothelial-cell replacement in transplant arteriosclerosis.Nat Med., 8:194 –195.

Hu Y, Davison F, Zhan Z, Xu Q. (2003). Endothelial replacement and angiogenesis in arteriosclerotic lesions of allografts are contributed by circulating progenitor cells.Circulation, 108:3122–3127.

Hur, J., Yoon, C.H., Kim, H.S., Choi, J.H., Kang, H.J., Hwang, K.K., et al. (2004). Characterization of two types of endothelial progenitor cells and their different contributions to neovasculogenesis. Arterioscler Thromb Vasc Biol 24(2), 288–293.

Imanishi, T., Hano, T. & Nishio, I. (2005) Estrogen reduces endothelial progenitor cell senescence through augmentation of telomerase activity. J Hypertens 23(9):1699-1706.

Iwaguro H, Yamaguchi J, Kalka C, Murasawa S, Masuda H, Hayashi S, Silver M, Li T, Isner JM, Asahara T, (2002). Endothelial progenitor cell vascular endothelial growth factor gene transfer for vascular regeneration. Circulation, 105:732–738.

Kalka C, Tehrani H, Laudernberg B, Vale P, Isner JM, Asahara T, Symes JF, (2000a). Mobilization of endothelial progenitor cells following gene therapy with VEGF165 in patients with inoperable coronary disease. Ann Thorac Surg., 70:829–834.

Kalka C, Masuda H, Takahashi T, Gordon R, Tepper O, Gravereaux E, Pieczek A, Iwaguro H, Hayashi S-I, Isner JM, Asahara T (2000b). Vascular endothelial growth factor165 gene transfer augments circulating endothelial progenitor cells in human subjects. Circ Res., 86:1198 –1202.

Kalka C, Masuda H, Takahashi T, Kalka-Moll WM, Silver M, Kearney M, Li T, Isner JM, Asahara T, (2000c). Transplantation of ex vivo expanded endothelial progenitor cells for therapeutic neovascularization. Proc Natl Acad Sci U S A. 97:3422–3427.

Kang H-J, Kim H-S, Zhang S-Y, Park K-W, Cho H-J, Koo B-K, Kim Y-J, Lee DS, Sohn D-W, Han K-S, Oh B-H, Lee M-M, Park Y-B, (2004). Effects of intracoronary infusion of peripheral blood stem cells mobilized with granulocyte-colony stimulating factor on left ventrricular systolic function and restenosis after coronary stenting in myocardial infarction: the MAGIC cell randomized clinical trial. Lancet, 363:751–756.

Kawamoto A, Gwon H-C, Iwaguro H, Yamaguchi J, Uchida S, Masuda H, Silver M, Ma H, Kearney M, Isner JM, Asahara T, (2001). Therapeutic potential of ex vivo expanded endothelial progenitor cells for myocardial ischemia. Circulation, 103:634–637.

Khan SS, Solomon MA, and McCoy JP Jr, (2005). Detection of circulating- endothelial cells and endothelial progenitor cells by flow cytometry. Cytometry B Clin Cytom64:1–8.

Kiernan, T.(2006). Endothelial progenitor cells in 2006 – Where are we now? http://www.irishheart.ie/iopen24/catalog/pub/Heartwise/2006/Spring/endothelial.pdf retrieved 6/22/2006. Link not found 5/1/2013

Kim, DH, Leu, HB, Ott, HC & Taylor, DO, Bertolini, F, Mancuso, P & Kerbel, RS, Boos, CJ, Goon, PKY, Lip, GYH, (2005). Multiple comments – Correspondence to the Editor on Circulating Endothelial Progenitor Cells. NEJM, 353:24, 2613-2616

Kleinman, ME, Blei, F, Gurtner, GC, (2005). Circulating Endothelial Progenitor Cells and Vascular Anomalies, Lymphatic Research and Biology, 3;4: 234-239.

Kocher AA, Schuster MD, Szabolcs MJ, Burkhoff D, Wang J, Homma S, Edwards NM, Itescu S. (2001). Neovascularization of ischemic myocardium by human bone-marrow-derived angioblasts prevents cardiomyocyte apoptosis, reduces remodeling and improves cardiac function. Nat Med., 7:430–436.

Kong D, Melo LG, Gnecchi M, Zhang L, Mostoslavski G, Liew CC, Pratt RE, Dzau VJ. (2004a). Cytokine-induced mobilization of circulating endothelial progenitor cells enhances repair of injured arteries. Circulation, 110:2039 –2046.

Kong D, Melo LG, Mangi AA, Zhang L, Lopez-Ilasaca M, Perrella MA, Liew CC, Pratt RE, Dzau VJ, (2004b). Enhanced inhibition of neointimal hyperplasia by genetically engineered endothelial progenitor cells. Circulation, 109:1769 –1775.

Kuvin JT, et al. (2003a). Assessment of peripheral vascular endothelial function with finger arterial pulse wave amplitude. Am Heart J, 146:168-74.

Kuvin JT, et al. (2003b). Peripheral arterial tonometry during hyperemia is blunted in patients with coronary artery disease. J Am Coll of Cardiology, 41:Suppl:269A.

Lapidot T, and Petit, I (2002) Current understanding of stem cell mobilization: The roles of chemokines, proteolytic enzymes, adhesion molecules, cytokines, and stromal cells. Experimental Hematology, 30:973–98

Laufs U, Werner N, Link A, Endres M, Wassmann S, Jurgens K, Miche E, Bohm M, and Nickenig G (2004). Physical training increases endothelial progenitor cells, inhibits neointima formation, and enhances angiogenesis. Circulation 109: 220–226.

Llevadot J, Murasawa S, Kureishi Y, Uchida S, Masuda H, Kawamoto A, Walsh K, Isner JM, Asahara T, (2001). HMG-CoA reductase inhibitor mobilizes bone marrow-derived endothelial progenitor cells. J Clin Invest., 108:399–405.

Lloyd-Jones, D. and Tian, L. (2006). Predicting Cardiovascular Risk, So What Do We Do Now?. Arch Intern. Med, 166, 1342-1343.

Loomans CJM, de Koening EJP, Staal FJT, Rookmaaker MB, Verseyden C, de Boer HC, Verhaar MC, Braam B, Rebelink TJ, van Zonneveld A-J. (2004). Endothelial progenitor cell dysfunction. A novel concept in the pathogenesis of vascular complications of type I diabetes. Diabetes, 53:195–199.

Losordo DW, Isner JM, Diaz-Sandoval LJ, (2003). Endothelial Recovery. The next target in restenosis prevention. Circulation, 107:2635–2637.

Lusis, A.J. (2000). Atherosclerosis. Nature 407(6801), 233–241. DIGITAL LINK N/A

Massa M, Rosti V, Ferrario M, Campanelli R, Ramajoli, Rosso R, De Ferrari GM, Ferlini M, Goffredo L, Bertoletti A, Klersy C, Pecci A, Moratti R, Tavazzi, (2005). Increased circulating hematopoietic and endothelial progenitor cells in the early phase of acute myocardial infarction. Blood,105:199 –206.

Orlic D, Kajstura J, Chimenti S, Limana F, Jakoniuk I, Quaini F, Nadal-Ginard B, Bodine DM, Leri A, Anversa P. (2001). Mobilized bone marrow cells repair the infarcted heart, improving function and survival. Proc Natl Acad Sci U S A. 98:10344 –10349.

Peichev M, Naiyer AJ, Pereira D, Zhu Z, Lane WJ, Williams M, Oz MC, Hicklin DJ, Witte L, Moore MA, and Rafii S (2000). Expression of VEGFR-2 and AC133 by circulating human CD34+ cells identifies a population of functional endothelial precursors. Blood 95: 952–958.

Perin EC, Dohmann HFR, Borojevic R, Silva SA, Sousa AL, Mesquita CT, Rossi MI, Carvalho AC, Dutra HS, Dohmann HJ, Silva GV, Belem L, Vivacqua R, Rangel FO, Esporcatte R, Geng YJ, Vaughn WK, Assad JA, Mesquita ET, Willerson JT, (2003). Transendocardial, autologous bone marrow cell transplantation for severe, chronic ischemic heart failure. Circulation, 107:2294 –2302.

Powell TM, Paul JD, Hill JM, Thompson M, Benjamin M, Rodrigo M, McCoy JP, Read EJ, Khuu HM, (2005). Leitman SF, Finkel T, Cannon RO III. Granulocyte colony stimulating factor mobilizes functional endothelial progenitor cells in patients with coronary artery disease. Arterioscler Thromb Vasc Biol., 25:1– 6.

Rafii S, Lyden D (2003). Therapeutic stem and progenitor cell transplantation for organ vascularisation and regeneration. Nat Med 9: 702–712.

Rauscher FM, Goldschmidt-Clermont PJ, Davis BH, Wang T, Gregg D, Ramaswami P, Pippen AM, Annex BH, Dong C, Taylor DA, (2003). Aging, progenitor cell exhaustion, and atherosclerosis. Circulation, 108:457–463.

Ross R. (1999). Atherosclerosis – An inflammatory disease. N Engl J Med., 340:115–126.

Rubanyi GM. (1993). The role of endothelium in cardiovascular homeostasis and diseases. J Cardiovasc Pharmacol., 22(Suppl):S1–S4.

Sata M, Saiura A, Kunisato A, Tojo A, Okada S, Tokuhisa T, Hirai H, Makuuchi M, Hirata Y, Nagai R. (2002). Hematopoietic stem cells differentiate into vascular cells that participate in the pathogenesis of atherosclerosis. Nat Med., 8:403– 409.

Schachinger V, Assmus B, Britten MB, Honold J, Lehman R, Teupe C, Abolmaali ND, Vogt TJ, Hofmann WK, Martin H, Dimmeler S, Zeiher AM, (2004). Transplantation of progenitor cells and regeneration enhancement in acute myocardial infarction: final one-year results of the TOPCARE-AMI trial. J Am Coll Cardiol., 44:1690 –1699.

Schatteman GC, Hanlon HD, Jiao C, Dodds SG, Christy BA. (2000). Blood derived angioblasts accelerate blood flow restoration in diabetic mice. J Clin Invest., 106:571–578.

Scheubel RJ, Zorn H, Rolf-Edgar S, Kuss O, Morawietz, Holtz J, Simm A. (2003). Age-dependent depression in circulating endothelial progenitor cells in patients undergoing coronary artery bypass grafting. J Am Col Cardiol., 42:2073–2080.

Segal, M.S., Shah, R., Afzal, A., Perrault, C.M., Chang, K., Schuler, A., et al. (2006). Nitric oxide cytoskeletal-induced alterations reverse the endothelial progenitor cell migratory defect associated with diabetes. Diabetes 55(1), 102-109

Shi Q, Raffi, Wu MH, Wijelath ES, Yu C, Ishida A, Fujita Y, Kothari S, Mohle R, Sauvage LR, Moore MAS, Storb RF, Hammond WP. (1998). Evidence of circulating bone-marrow derived endothelial cells. Blood, 92:362–367.

Shi Q, Bhattacharya V, Hong-De Wu M, Sauvage LR. (2002). Utilizing granulocyte colony-stimulating factor to enhance vascular graft endothelialization from circulating blood cells. Ann Vasc Surg., 16:314 –320.

Shintani S, Murohara T, Ikeda H, Ueni T, Honma T, Katoh A, Sasaki K, Shimada T, Oike Y, Imaizumi T, (2001). Mobilization of endothelial progenitor cells in patients with acute myocardial infarction. Circulation, 103:2776 –2779.

Shirota, T., Yasui, H., Shimokawa, H. & Matsuda, T. (2003). Fabrication of endothelial progenitor cell (EPC)-seeded intravascular stent devices and in vitro endothelialization on hybrid vascular tissue. Biomaterials 24(13), 2295–2302.

Simper D, Wang S, Deb A, Holmes D, McGregor C, Frantz R, Kushawa SS, Caplice NM, (2003). Endothelial progenitor cells are decreased in blood of cardiac allograft patients with vasculopathy and endothelial cells of non cardiac origin are enriched in transplant atherosclerosis. Circulation, 107:143–149.

Spyridopoulos I, Haendeler J, Urbich C, Brummendorf TH, Oh H, Schneider MD, Zeiher AM, Dimmeler S, (2004). Statins enhance migratory capacity by upregulation of the telomere repeat-binding factor TRF2 in endothelial progenitor cells. Circulation, 110:3136 –3142.

Stamm C, Westphal B, Kleine H-D, Petzsch M, Kittner C, Klinge H, Schumichen C, Nienaber CA, Freund M, Steinhoff G, (2003). Autologous bonemarrow transplantation for myocardial regeneration. Lancet, 361:45–46.

Strauer BE, Brehm M, Zeus T, Kostering M, Hernandez A, Sorg RV, Kogler G, Wernet P, (2002). Repair of infarcted myocardium by autologous intracoronary mononuclear bone marrow cell transplantation in humans. Circulation, 106:1913–1918.

Strehlow K, Werner N, Berweiler J, Link A, Dirnagl U, Priller J, Laufs K, Ghaeni L, Milosevic M, Bohm M, Nickenig G, (2003). Estrogen increases bone-marrow derived endothelial progenitor cell production and diminishes neointima formation.Circulation, 107:3059 –3065.

Takahashi T, Kalka C, Masuda H, Chen D, Silver M, Kearney M, Magner M, Isner JM, Asahara T, (1999). Ischemia- and cytokine-induced mobilization of bone-marrow-derived endothelial progenitor cells for neovascularization. Nat Med., 5:434–438.

Tepper OM, Galiano RD, Capla JM, Kalka C, Gagne PJ, Jacobwotiz GR, Levine JP, Gurtner GC. (2002). Human endothelial progenitor cells from type II diabetes exhibit impaired proliferation, adhesion, and incorporation into vascular structures.Circulation, 106:2781–2786.

Tse HF, Kwong YL, Chan JK, Lo G, Ho CL, and Lau CP (2003). Angiogenesis in ischaemic myocardium by intramyocardial autologous bone genesis marrow mononuclear cell implantation. Lancet 361: 47–49.

Tung, R, Kaul, S, Diamond, GA, Shah, PK (2006). Drug-Eluting Stents for the Management of Restenosis: A Critical Appraisal of the Evidence. Annals of Internal Medicine, 144;12: 913-919.

Valenzuela-Fernandez A, Planchenault T, Baleux F, et al. (2002) Leukocyte elastase negatively regulates stromal cell-derived factor-1 (SDF)/CXCR4 binding and functions by amino-terminal processing of SDF-1 and CXCR4. J Biol Chem 277:156

Valgimigli M, Rigolin GM, Fucili A, Della Porta M, Soukhomovskaia O, Malagutti P, Bugli AM, Bragottu LZ, Francolini G, Mauro E, Castoldi G, Ferrari R, (2004). CD34 and endothelial progenitor cells in patients with various degrees of congestive heart failure. Circulation, 110:1209–1212.

Vasa M, Fichtlscherer S, Adler K, Aicher A, Martin H, Zeiher AM, Dimmeler S. (2001a). Increase in circulating endothelial progenitor cells by statin therapy in patients with stable coronary artery disease. Circulation, 103:2885–2890.

Vasa M, Fichtlscherer S, Aicher A, Adler K, Urbich C, Martin H, Zeiher AM, Dimmeler S. (2001b). Number and migratory activity of circulating endothelial progenitor cells inversely correlates with risk factors for coronary artery disease. Circ Res., 89:e1– e7.

Vasan, RS, (2006). Biomarkers of Cardiovascular Disease: Molecular Basis and Practical Considerations, Circulation, 113:2335-2362.

Verma S, Kukiszewski MA, Li S-H, Szmitko PE, Zucco L, Wang C-H, Badiwala MV, Mickle DAG, Weisel RD, Fedak PWM, Stewart DJ, Kutrik MJB, (2004). C-reactive protein attenuates endothelial progenitor cell survival, differentiation, and function.Circulation, 109:r91–r100.

Verma, S. and Marsden, P.A. (2005). Nitric Oxide-Eluting Polyurethanes – Vascular Grafts of the Future? New England Journal Medicine, 353 (7), 730-731.

Verma S, Szmitko, PE, (2006). The vascular biology of peroxisome proliferator-activated receptors: Modulation of atherosclerosis. Can J Cardiol, 22 (Suppl B):12B-17B.

Walter DH, Rittig K, Bahlmann FH, Kirchmair R, Silver M, Murayama T, Nishimura H, Losordo DW, Asahara T, Isner JM, (2002). Statin therapy accelerates reendothelialization: a novel effect involving mobilization and incorporation of bone marrow-derived endothelial progenitor cells. Circulation, 105:3017–3024.

Werner N, Junk S, Laufs L, Link A, Walenta K, Bohm M, Nickenig G., (2003). Intravenous transfusion of endothelial progenitor cells reduces neointima formation after vascular injury. Circ Res., 93:e17– e24.

Werner N, Kosiol S, Schiegl T, Ahlers P, Walenta K, Link A, Böhm M, Nickenig G. (2005a). Circulating Endothelial Progenitor Cells and Cardiovascular Outcomes,NEJM, 353: 999-1007

Werner, N & Nickenig, G. (2005b). Authors Reply to Correspondence to the Editor on Circulating Endothelial Progenitor Cells. NEJM, 353:24, 2613-2616

Widlansky ME, et al. (2003). The clinical implications of endothelial dysfunction. J Am Coll of Cardiology, 42:1149-60.

Wollert KC, Meyer GP, Latz J, Ringes-Lichtenberg S, Lippolt P, Breindenbach C, Fichtner S, Korte T, Hornig B, Messinger D, Arseniev L, Hartenstein B, Ganser A, Drexler H (2004). Intracoronary autologous bonemarrow cell transfer after myocardial infarction: the BOOST randomised controlled clinical trial. Lancet, 364:141–148.

Yamaguchi J, Kusano KF, Masuo O, Kawamoto A, Silver M, Murasawa S, Bosch-Marce M, Masuda H, Losordo DW, Isner JM, Asahara T. (2003). Stromal cell-derived factor-1 effects on ex vivo expanded endothelial progenitor cell recruitment for ischemic neovascularization. Circulation, 107:1322–1328.

Yoon YS, Park JS, Tkebuchava T, Luedeman C, Losordo DW. (2004). Unexpected severe calcification after transplantation of bone marrow cells in acute myocardial infarction. Circulation, 109:3154 –3157.

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Percutaneous Transluminal Angioplasty and Stenting (PTAS) – Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis

Posted in Bio Instrumentation in Experimental Life Sciences Research, Frontiers in Cardiology and Cardiovascular Disorders, Medical Devices R&D and Inventions, Origins of Cardiovascular Disease, Stents & Tools, Uncategorized, tagged Angioplasty, Artery, Atherosclerosis, Intracranial arterial stenosis, New England Journal Medicine, Stent, Stroke on July 5, 2012| 1 Comment »

Percutaneous Transluminal Angioplasty and Stenting (PTAS) – Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis

Reporter: Aviva Lev-Ari, PhD, RN

RESULTS

Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis (Original Article, N Engl J Med 2011 ; 365 : 993 – 1003) . In the first paragraph of Results (page 996), the penultimate sentence should have read, “Of the 224 patients in the PTAS group, 16 (7.1%) did not have a stent placed (the procedure was not performed in 4 patients, the procedure was aborted before the lesion was accessed in 7, and angioplasty alone was performed in 5),”

http://www.nejm.org/doi/full/10.1056/NEJMx120039?query=TOC

BACKGROUND

Atherosclerotic intracranial arterial stenosis is an important cause of stroke that is increasingly being treated with percutaneous transluminal angioplasty and stenting (PTAS) to prevent recurrent stroke. However, PTAS has not been compared with medical management in a randomized trial.

METHODS

We randomly assigned patients who had a recent transient ischemic attack or stroke attributed to stenosis of 70 to 99% of the diameter of a major intracranial artery to aggressive medical management alone or aggressive medical management plus PTAS with the use of the Wingspan stent system. The primary end point was stroke or death within 30 days after enrollment or after a revascularization procedure for the qualifying lesion during the follow-up period or stroke in the territory of the qualifying artery beyond 30 days.

CONCLUSIONS

In patients with intracranial arterial stenosis, aggressive medical management was superior to PTAS with the use of the Wingspan stent system, both because the risk of early stroke after PTAS was high and because the risk of stroke with aggressive medical therapy alone was lower than expected.

http://www.nejm.org/doi/full/10.1056/nejmoa1105335

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Global Supplier Strategy for Market Penetration & Partnership Options (Niche Suppliers vs. National Leaders) in the Massachusetts Cardiology & Vascular Surgery Tools and Devices Market for Cardiac Operating Rooms and Angioplasty Suites

Posted in Aortic Valve: TAVR, TAVI vs Open Heart Surgery, Bio Instrumentation in Experimental Life Sciences Research, Cardiac & Vascular Repair Tools Subsegment, Ecosystems & Industrial Concentration in the Medical Device Sector, Exec Compensation in the Cardiac & Vascular Repair Tools Subsegment, Frontiers in Cardiology and Cardiovascular Disorders, Massachusetts Niche Suppliers and National Leaders, Medical Devices R&D and Inventions, Mitral Valve: Repair and Replacement, Stents & Tools, Valves & Tools, tagged Aortic valve, Coronary stent, Edwards Lifesciences, Edwards Lifesciences Corporation, Industry Concentration Ratio in Medical Devices Markets, Market Penetration Cost, Market Penetration in Medical Devices Market, Niche supplier, Peripheral, Stent, Vascular surgery on June 22, 2012| 12 Comments »

Global Supplier Strategy for Market Penetration & Partnership Options (Niche Suppliers vs. National Leaders) in the Massachusetts Cardiology & Vascular Surgery Tools and Devices Market for Cardiac Operating Rooms and Angioplasty Suites

Curator: Aviva Lev-Ari, PhD, RN

The ecosystem of Cardiac and Vascular Surgery for Repair or Replacement by Implantation of a new blood vessel or medical device covers the following procedure-related devices and tools now in use:

Arterial catheterization kit
Embolectomy catheters
Occlusion catheter
Coronary stents
Neurovascular stents
Carotid stents
External and internal carotid shunts
Peripheral stents
Biliary stents
Micro vascular clips
Stainless steel tunneler vascular graft
Cardiopulmonary bypass vascular catheter
Coronary stent graft system
Catheter tip occluder
Synthetic/biological composite vascular graft
Valvulotome tools
Aortic Valve
Mitral Valve
Angioplasty Guided Wires

No Aorta valve suppliers in MA. The National Leader supplier Edwards Lifesciences and its SAPIEN product for Transcatheter Aortic-Valve Implantation (TAVI) and Replacement (TAVR) is covered in Executive Compensation and Comparator Group Definition in the Cardiac and Vascular Medical Devices Sector: A Bright Future for Edwards Lifesciences Corporation in the Transcatheter Heart Valve Replacement Market 6/20/2012

http://pharmaceuticalintelligence.com/2012/06/19/executive-compensation-and-comparator-group-definition-in-the-cardiac-and-vascular-medical-devices-sector-a-bright-future-for-edwards-lifesciences-corporation-in-the-transcatheter-heart-valve-replace/

Medical Devices Market in Massachusetts: Product Concentration Ratios (1 to 10) by Product and Partnership Target Advantage – Niche Suppliers vs. National Leader in the Cardiology & Vascular Surgery Tools and Devices in use in Cardiac Operating Rooms and in Angioplasty Suites

Industry Concentration Ratios per Product Line in the Cardiac and Vascular Medical Devices Segments
A	B	C	D	E	F	G	H	I	J
		US comparison				MA comparison
Cardiology & Vascular Surgery Tools and Devices in use	Global Suppliers	US Suppliers	Market share	Global ratio	Index	MA Suppliers	Market share	Global ratio	Index
Arterial catheterization kit	4	6	0.09	0.40	5.6	2	0.14	0.67	3.6
Embolectomy catheters	11	28	0.03	0.28	1.9	3	0.07	0.79	2.4
Occlusion catheter	1	7	0.11	0.13	2.8	3	0.20	0.25	2.4
Coronary stents	11	34	0.02	0.24	1.7	2	0.07	0.85	2.6
Neurovascular stents	2	6	0.11	0.25	4.5	1	0.25	0.67	5.5
Carotid stents	1	12	0.07	0.08	1.7	1	0.33	0.50	5.5
External and internal carotid shunts	2	5	0.13	0.29	5.5	2	0.20	0.50	3.7
Peripheral stents	0	7	0.13	0.00	1.0	1	0.50	0.00	1.0
Biliary stents	7	13	0.05	0.35	3.1	1	0.11	0.88	3.6
Micro vascular clips	3	6	0.10	0.33	5.2	2	0.17	0.60	3.7
Stainless steel tunneler vascular graft	3	3	0.14	0.50	10.0	1	0.20	0.75	5.1
Cardiopulmonary bypass vascular catheter	14	39	0.02	0.26	1.6	5	0.05	0.74	2.0
Coronary stent graft system	0	6	0.14	0.00	1.0	1	0.50	0.00	1.0
Catheter tip occluder	1	6	0.13	0.14	3.3	2	0.25	0.33	3.3
Synthetic/biological composite vascular graft	3	5	0.11	0.38	6.3	2	0.17	0.60	3.7
Valvulotome tools	3	6	0.10	0.33	5.2	1	0.20	0.75	5.1
Aortic Valve	2	9	0.08	0.18	2.9	0	0.33	1.00	10.0
Mitral Valve	4	7	0.08	0.36	4.8	0	0.20	1.00	6.4
Angioplasty Guided Wires	8	11	0.05	0.42	3.7	2	0.09	0.80	3.0
					126				27
Source for A, B, C, G – http://www.medicregister.com
Source for D,E,F,H,I,J – Computed ratios per formulas below byAviva Lev-Ari, PhD, RN
D = 1/(1+B+C) = projected market share assuming non-differential production capacity

E = B/(B+C) = fraction of global among all suppliers

F = DE$F$24+1 = product of “D” and “E”, scaled to be in the range from 1 to 10

“H” is the same as “D” but with MA suppliers replacing “US suppliers”
“I” is the same as “E” but with MA suppliers replacing “US suppliers”
“J” is the same as “F” but with MA suppliers replacing “US suppliers”

Product Advantage for Partnership with Niche Suppliers in MA

Product Concentration Ratio (PRC) for Tools and Devices in use in Cardiology & Vascular Surgery	Targeting a Niche Supplier based in Massachusetts	Aiming at the Industry Leader
Arterial catheterization kitPRC = 3.6	Lemaitre Vascular, Inc. www.lemaitre.comBurlington Smiths Medical ASD, Inc Weston
External and internal carotid shuntsPRC = 3.7	Bard Electrophysiology www.bardep.comLowell Lemaitre Vascular, Inc. www.lemaitre.com Burlington
Micro vascular clipsPRC = 3.7	Lemaitre Vascular, Inc. www.lemaitre.comBurlington Life Instrument Corporation www.lifeinstruments.com Braintree
Stainless steel tunneler vascular graftPRC = 5.1	Lemaitre Vascular, Inc. www.lemaitre.comBurlington
Cardiopulmonary bypass vascular catheterPRC = 2	Abiomed, Inc. www.abiomed.comDanvers Vortex Medical Inc www.angiovac.com Norwell Lemaitre Vascular, Inc. www.lemaitre.com Burlington Clinical Instruments Intl., Inc. Southbridge Smiths Medical ASD, Inc Weston
Coronary stent graft systemPRC = 2.6	Lemaitre Vascular, Inc. www.lemaitre.comBurlington
Catheter tip occluderPRC = 2.4	Lemaitre Vascular, Inc. www.lemaitre.comBurlington Clinical Instruments Intl., Inc. Southbridge
Valvulotome toolsPRC = 5.1	Lemaitre Vascular, Inc. www.lemaitre.comBurlington

Product Advantage for Partnership with National Leader in MA

Cardiology & Vascular Surgery Tools and Devices in use	Niche Supplier based in Massachusetts	Industry Leader
Neurovascular stentsPRC = 5.5		Boston Scientific Corporation www.bostonscientific.comNatick
Carotid stents PRC = 5.5		Boston Scientific Corporation www.bostonscientific.comNatick
Peripheral stentsPRC = 1		Boston Scientific Corporation www.bostonscientific.comNatick
Biliary stentsPRC = 3.6		Boston Scientific Corporation www.bostonscientific.comNatick

Product Advantage for Partnership with Niche Suppliers and National Leader in MA

Cardiology & Vascular Surgery Tools and Devices in use	Niche Supplier based in Massachusetts	Industry Leader
Embolectomy cathetersPRC = 2.4	Lemaitre Vascular, Inc. www.lemaitre.comBurlington Clinical Instruments Intl., Inc. Southbridge	Boston Scientific Corporation www.bostonscientific.comNatick
Occlusion catheterPRC = 2.4	Lemaitre Vascular, Inc. www.lemaitre.comBurlington Telemed Systems Inc. www.telemedsystems.com Hudson	Boston Scientific Corporation www.bostonscientific.comNatick
Coronary stentsPRC = 2.6	Lemaitre Vascular, Inc. www.lemaitre.comBurlington	Boston Scientific Corporation www.bostonscientific.comNatick
Synthetic/biological composite vascular graftPRC = 3.7	Lemaitre Vascular, Inc. www.lemaitre.comBurlington	Boston Scientific Corporation www.bostonscientific.comNatick
Angioplasty Guided WiresPRC = 3.0	Arrow International, Walrus DivisionWoburn	Boston Scientific Corporation www.bostonscientific.comNatick

Source:

http://www.medicregister.com/Cardiology_Vascular_Surgery/Categories/cid2.htm

Penetration Strategy for a Global Supplier Targeting the US Market in Massachusetts

Customized predictions of penetration cost and estimation of potential revenues based on the industry segment concentration ratios in the Table above per Partnership Option are part of an Actionable Strategic Market Entry Plan in Massachusetts.

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Aviva Lev-Ari, PhD, RN

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Posts Tagged ‘Stent’

Percutaneous Transluminal Angioplasty and Stenting (PTAS) – Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis

Percutaneous Transluminal Angioplasty and Stenting (PTAS) – Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis

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Global Supplier Strategy for Market Penetration & Partnership Options (Niche Suppliers vs. National Leaders) in the Massachusetts Cardiology & Vascular Surgery Tools and Devices Market for Cardiac Operating Rooms and Angioplasty Suites

Global Supplier Strategy for Market Penetration & Partnership Options (Niche Suppliers vs. National Leaders) in the Massachusetts Cardiology & Vascular Surgery Tools and Devices Market for Cardiac Operating Rooms and Angioplasty Suites

Curator: Aviva Lev-Ari, PhD, RN

Medical Devices Market in Massachusetts: Product Concentration Ratios (1 to 10) by Product and Partnership Target Advantage – Niche Suppliers vs. National Leader in the Cardiology & Vascular Surgery Tools and Devices in use in Cardiac Operating Rooms and in Angioplasty Suites

Product Advantage for Partnership with Niche Suppliers in MA

Product Advantage for Partnership with National Leader in MA

Product Advantage for Partnership with Niche Suppliers and National Leader in MA

Penetration Strategy for a Global Supplier Targeting the US Market in Massachusetts

Customized predictions of penetration cost and estimation of potential revenues based on the industry segment concentration ratios in the Table above per Partnership Option are part of an Actionable Strategic Market Entry Plan in Massachusetts.

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Leaders in Pharmaceutical Business Intelligence Group, LLC, Doing Business As LPBI Group, Newton, MA

Posts Tagged ‘Stent’

Drug Eluting Stents: On MIT’s Edelman Lab’s Contributions to Vascular Biology and its Pioneering Research on DES

Drug Eluting Stents: On MIT‘s Edelman Lab’s Contributions to Vascular Biology and its Pioneering Research on DES

Vascular Biology and Cardiovascular Disease

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Perlecan is a heparin-sulfate proteoglycan that might be critical for regulation of vascular repair by inhibiting the binding and mitogenic activity of basic fibroblast growth factor-2 (bFGF-2) in vascular smooth muscle cells .

The Role of Amyloid beta (A) in Creation of Vascular Toxic Plaque

Endothelial Damage as an Inflammatory State

Exposure to mechanical strain increased the paracrine inhibition of vascular smooth muscle cells (VSMCs) by endothelial cells.

Neointimal Formation, Shear Stress, and Remodelling with Reference to Diabetes

A Rattle Bag of Science and the Art of Translation

Defining TRANSLATIONAL Medicine

Evaluating a new way to open clogged arteries: Computational model offers insight into mechanisms of drug-coated balloons.

Modeling drug release

http://circ.ahajournals.org/content/127/20/2047.short http://www.mit.edu/people/vbk/Circulation_2013.pdf http://www.sciencedaily.com/…13/05/130521121513.ht… Circulation, 2013; 127 (20): 2047 – 2055 http://dx.doi.org/10.1161/CIRCULATIONAHA.113.002051;

Conclusion

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Endothelial Dysfunction, Diminished Availability of cEPCs, Increasing CVD Risk for Macrovascular Disease – Therapeutic Potential of cEPCs

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Percutaneous Transluminal Angioplasty and Stenting (PTAS) – Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis

Percutaneous Transluminal Angioplasty and Stenting (PTAS) – Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis

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Global Supplier Strategy for Market Penetration & Partnership Options (Niche Suppliers vs. National Leaders) in the Massachusetts Cardiology & Vascular Surgery Tools and Devices Market for Cardiac Operating Rooms and Angioplasty Suites

Global Supplier Strategy for Market Penetration &amp; Partnership Options (Niche Suppliers vs. National Leaders) in the Massachusetts Cardiology &amp; Vascular Surgery Tools and Devices Market for Cardiac Operating Rooms and Angioplasty Suites

Curator: Aviva Lev-Ari, PhD, RN

Medical Devices Market in Massachusetts: Product Concentration Ratios (1 to 10) by Product and Partnership Target Advantage – Niche Suppliers vs. National Leader in the Cardiology & Vascular Surgery Tools and Devices in use in Cardiac Operating Rooms and in Angioplasty Suites

Product Advantage for Partnership with Niche Suppliers in MA

Product Advantage for Partnership with National Leader in MA

Product Advantage for Partnership with Niche Suppliers and National Leader in MA

Penetration Strategy for a Global Supplier Targeting the US Market in Massachusetts

Customized predictions of penetration cost and estimation of potential revenues based on the industry segment concentration ratios in the Table above per Partnership Option are part of an Actionable Strategic Market Entry Plan in Massachusetts.

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http://circ.ahajournals.org/content/127/20/2047.short
http://www.mit.edu/people/vbk/Circulation_2013.pdf
http://www.sciencedaily.com/…13/05/130521121513.ht…
Circulation, 2013; 127 (20): 2047 – 2055
http://dx.doi.org/10.1161/CIRCULATIONAHA.113.002051;

Global Supplier Strategy for Market Penetration & Partnership Options (Niche Suppliers vs. National Leaders) in the Massachusetts Cardiology & Vascular Surgery Tools and Devices Market for Cardiac Operating Rooms and Angioplasty Suites