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Posts Tagged ‘congestive heart failure’


Heart-Failure–Related Mortality Rate: CDC Reports comparison of 2000, 2012, 2014  – the decease is steadily reversed

Reporter: Aviva Lev-Ari, PhD, RN

 

The report, which examined heart-failure trends between 2000 and 2014, showed that the age-adjusted rate for HF-related mortality was 105.4 per 100,000 population in 2000 and only 81.4 per 100,000 in 2012 (P<0.05). However, the rate then started a slow but steady climb, reaching 84.0 per 100,000 in 2014.

Not so surprising: men of all ages still had a higher death rate vs women in 2014, and black individuals had a higher rate than whites (91.5 vs 87.3 deaths per 100,000) and Hispanics (53.3 per 100,000).

 

CDC: Heart-Failure–Related Mortality Rate Climbs After Decade-Long Decrease

Deborah Brauser

January 04, 2016

http://www.medscape.com/viewarticle/856704?nlid=95763_3866&src=wnl_edit_medp_card&uac=93761AJ&spon=2&impID=944924&faf=1

NCHS Data Brief

Number 231, December 2015

Recent Trends in Heart Failure-related Mortality: United States, 2000–2014

PDF Version Adobe PDF file (351 KB)

Hanyu Ni, Ph.D.; and Jiaquan Xu, M.D.

 

Key findings

Data from the National Vital Statistics System, Mortality

  • The age-adjusted rate for heart failure-related deaths decreased from 2000 through 2012 but increased from 2012 through 2014.
  • The death rate for heart failure was higher for the
    non-Hispanic black population than for the non-Hispanic white and Hispanic populations.
  • The death rate was higher for men than for women in all age groups. The gap in the death rate for adults aged 45–64 and 85 and over increased over time.
  • The percentage of heart failure-related deaths that occurred in a hospital decreased from 2000 through 2014.
  • The percentage of heart failure-related deaths for adults aged 45 and over with coronary heart disease as the underlying cause of death decreased 32%, from 34.9% in 2000 to 23.9% in 2014.

Heart failure is a major public health problem associated with significant hospital admission rates, mortality, and costly health care expenditures, despite advances in the treatment and management of heart failure and heart failure-related risk factors (1–4). Using data from the multiple cause of death files, this report describes the trends in heart failure-related mortality from 2000 through 2014 for the U.S. population, by age, sex, race and Hispanic origin, and place of death. Heart failure-related deaths were identified as those with heart failure reported anywhere on the death certificate, either as an underlying or contributing cause of death. Changes in the underlying causes of heart failure-related deaths are also described in this report.

Keywords: mortality, heart failure, trend, National Vital Statistics System

SOURCE

http://www.cdc.gov/nchs/data/databriefs/db231.htm

 

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G Protein–Coupled Receptor and S-Nitrosylation in Cardiac Ischemia

Curators: Larry H. Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN

 

This recently published article delineates a role of G-protein-coupled receptor with S-nitrosylation in outcomes for acute coronary syndrome.

Convergence of G Protein–Coupled Receptor and S-Nitrosylation Signaling Determines the Outcome to Cardiac Ischemic Injury

Z. Maggie Huang1, Erhe Gao1, Fabio Vasconcelos Fonseca2,3, Hiroki Hayashi2,3, Xiying Shang1, Nicholas E. Hoffman1, J. Kurt Chuprun1, Xufan Tian4, Doug G. Tilley1, Muniswamy Madesh1, David J. Lefer5, Jonathan S. Stamler2,3,6, and Walter J. Koch1*
1 Center for Translational Medicine, Temple University School of Medicine, Philadelphia, PA
2 Institute for Transformative Molecular Medicine, Case Western Reserve Univ SOM, Cleveland, OH
3 Department of Medicine, Case Western Reserve University, Cleveland, OH
4 Department of Biochemistry, Thomas Jefferson University, Philadelphia, PA
5 Department  Surgery, Div of Cardiothoracic Surgery, Emory University School of Medicine, Atlanta, GA
6 University Hospitals Harrington Discovery Institute, Cleveland, OH

Sci. Signal., 29 Oct 2013; 6(299), p. ra95         http:dx.doi.org/10.1126/scisignal.2004225

Abstract

Heart failure caused by ischemic heart disease is a leading cause of death in the developed world. Treatment is currently centered on regimens involving

  • G protein–coupled receptors (GPCRs) or nitric oxide (NO).

These regimens are thought to target distinct molecular pathways. We showed that

  • these pathways are interdependent and converge on the effector GRK2 (GPCR kinase 2) to regulate myocyte survival and function.

Ischemic injury coupled to

  • GPCR activation, including GPCR desensitization and myocyte loss,
  • required GRK2 activation,

and we found that cardioprotection mediated by inhibition of GRK2 depended on

  • endothelial nitric oxide synthase (eNOS) and
  • was associated with S-nitrosylation of GRK2.

Conversely, the cardioprotective effects of NO bioactivity were absent in a knock-in mouse with a form of GRK2 that cannot be S-nitrosylated. Because GRK2 and eNOS inhibit each other,

the balance of the activities of these enzymes in the myocardium determined the outcome to ischemic injury. Our findings suggest new insights into

  • the mechanism of action of classic drugs used to treat heart failure and
  • new therapeutic approaches to ischemic heart disease.

* Corresponding author. E-mail: walter.koch@temple.edu
Citation: Z. M. Huang, E. Gao, F. V. Fonseca, H. Hayashi, X. Shang, N. E. Hoffman, J. K. Chuprun, X. Tian, D. G. Tilley, M. Madesh, D. J. Lefer, J. S. Stamler, W. J. Koch, Convergence of G Protein–Coupled Receptor and S-Nitrosylation Signaling Determines the Outcome t

 Editor’s Summary

Sci. Signal., 29 Oct 2013; 6(299), p. ra95 [DOI: 10.1126/scisignal.2004225]

NO More Heart Damage

Damage caused by the lack of oxygen and nutrients that occurs during myocardial ischemia can result in heart failure. A therapeutic strategy that helps to limit the effects of heart failure is to

  • increase signaling through G protein–coupled receptors (GPCRs)
  • by inhibiting GRK2 (GPCR kinase 2), a kinase that
    • desensitizes GPCRs.

Another therapeutic strategy provides S-nitrosothiols, such as nitric oxide, which can be

  • added to proteins in a posttranslational modification called S-nitrosylation.

Huang et al. found that the ability of S-nitrosothiols to enhance cardiomyocyte survival after ischemic injury required the S-nitrosylation of GRK2, a modification that inhibits this kinase. Mice bearing a form of GRK2 that could not be S-nitrosylated 

  • were more susceptible to cardiac damage after ischemia.

These results suggest that therapeutic strategies that promote the S-nitrosylation of GRK2 could be used to treat heart failure after myocardial ischemia.

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Source of Stem Cells to Ameliorate Damaged Myocardium (Part 2)

Author and Curator: Larry H. Bernstein, MD, FCAP

and

Curator: Aviva Lev-Ari, PhD, RN

 

This is Part 2 of a 3 part series of perspectives on stem cell applications to regenerating damaged myocardium.

Progenitor Cell Transplant for MI and Cardiogenesis  (Part 1)
Larry H. Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN
https://pharmaceuticalintelligence.com/2013-10-27/larryhbern/Progenitor-Cell-Transplant-for-MI,-and-cardiogenesis/

Source of Stem Cells to Ameliorate Damage Myocardium (Part 2)
Larry H. Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN
https://pharmaceuticalintelligence.com/2013-10-29/larryhbern/Source_of_Stem_Cells_to_Ameliorate_ Damaged_Myocardium/

An Acellular 3-Dimensional Collagen Scaffold  Induces Neo-angiogenesis (Part 3)
Larry H. Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN
https://pharmaceuticalintelligence.com/2013-10-29/larryhbern/An_Acellular_3-Dimensional_Collagen_Scaffold _Induces_Neo-angiogenesis/

This series of articles discusses the difficulties we have encountered in adopting stem cell research to clinical therapeutics in regeneration of cardiac tissue damaged post myocardial infarct.  Enormous problems have been encountered in the selection of progenitor cells, the growth into compatible and functional myocardial tissue, and the survival of the myocardium.  Part I went into some detail on a method of obtaining suitable cells, growing them in sheets, and transferring the sheets to the surface for regeneration and repair, which is now going into clinical trials.  Part I will be confined to the importance of source of progenitor cells, whether adult stem cells or umbilical cord blood.

Do Adult Stem Cells Ameliorate the Damaged Myocardium? Human Cord Blood as a Potential Source of Stem Cells

Elise M.K. Furfaro and Mohamed A. Gaballa
Dept Internal Med, Sarver Heart Center, University of Arizona, College of Medicine, Tucson, AZ
Current Vascular Pharmacology, 2007, 5, 27-44  © 2007 Bentham Science Publishers Ltd.

Abstract: The heart does not mend itself after infarction. Cell-based strategies have promising therapeutic potential. Recent clinical and pre-clinical studies demonstrate varying degrees of improvement in cardiac function using different adult stem cell types such as bone marrow (BM)-derived progenitor cells and skeletal myoblasts. However, the efficacy of cell therapy after myocardial infarction (MI) is inconclusive and the cellular source with the highest potential for regeneration is unclear. Clinically, BM and skeletal muscle are the most commonly used sources of autologous stem cells. One major pitfall of using autologous stem cells is that the number of functional cells is generally depleted in the elderly and chronically ill. Therefore, there is an urgent need for a new source of adult stem cells. Human umbilical cord blood (CB) is a candidate and appears to have several key advantages. CB is a viable and practical source of progenitor cells. The cells are naïve and what’s more, CB contains a higher number of immature stem/progenitor cells than BM.

We review recent clinical experience with adult stem cells and explore the potential of CB as a source of cells for cardiac repair following MI. We conclude that there is a conspicuous absence of clinical studies utilizing CB-derived cells and there is a pressing need for large randomized double-blinded clinical trials to assess the overall efficacy of cell-based therapy.

Keywords: Umbilical cord blood, adult stem cell, myocardial infarction, congestive heart failure, human bone marrow, skeletal muscle, angiogenesis

 INTRODUCTION

There is an urgent need for new and effective therapy for congestive heart failure (CHF). Heart cells may have a limited capacity to regenerate after myocardial infarction (MI), therefore the use of stem cells for cardiac repair is a logical option. In the past three years, clinical and pre-clinical stud-ies examined the potential of a variety of adult stem cells from different sources as therapy for cardiac disease [1-40]. Adult stem cells are typically chosen in clinical studies be-cause their use avoids the ethical problems associated with embryonic cells. Furthermore, adult stem cells were reported to be pluripotent, capable of differentiating to different cell types [41-45]. Bone marrow-derived hematopoietic stem cells, for example, appear to differentiate into brain cells, skeletal muscle cells, liver cells and cardiomyocytes [42-45]. However, the conclusions of the studies have been recently challenged [10-21, 45].

Regardless of the source, stem cells are difficult to iden-tify because they are hard to distinguish from other cells. No techniques are available to reliably identify stem cells other than surface markers. However, cell surface markers are fickle in that none of them appear to be unique to stem cells. For example, stem and progenitor cells of a varying degree of maturity all express the CD34+ surface marker.. Stem cells are typically recovered by isolation of mononuclear cells (MNCs) and subsequent enrichment for a subset of cells that express certain surface markers such as CD34+ or CD133+, etc. These precursors are commonly sorted using the fluores-cence activated sorting system [1-45].

Direct intramyocardial injection of stem cells into the myocardium is the common route of delivery during surgical intervention. This technique of local delivery of stem/ pro-genitor cells to the myocardium has been shown to be feasi-ble and safe in patients with heart disease [1-4, 10-12, 13, 20, 22, 28]. Other than open-heart surgery, the intra-coronary route appears to be the preferred approach in clinical studies because the stem cells are delivered directly to the affected area without traumatizing the myocardium or submitting the body to the systemic side effects of stem cell mobilization [5-9, 14-19, 21]. A complementary approach to increase the efficiency of progenitor cell transplantation is to enhance cell recruitment and retention in the infarcted heart. For example, stromal cell-derived factor (SDF-1α) has recently been shown to play a critical role in stem cell recruitment to the heart after MI [46].

Although there are other sources of adult stem cells such as adipose tissue [47, 48] and cardiac tissue [49, 50], this review briefly discusses clinical trials using BM stem cells and skeletal muscle myoblasts and pre-clinical studies that used cord blood (CB) cells for heart repair carried out during the past three years. This time period was chosen due to the plethora of excellent published reviews that serve as a foun-dation for this work [51-54]. In addition, the reader may re-fer to several recently published reviews [55-63]. Current clinical experience purports the safety and feasibility of BM stem cells and skeletal muscle myoblasts as autologous cell-therapy for cardiac disease [1-20, 22-30]. However, these cell sources have limitations. For example, recovering sufficient numbers of functional BM progenitor cells is a problem in the elderly and ill [64]. Cardiovascular diseases such as diabetes are associated with BM cell dysfunction [64]. Cardiac calcifications were reported in patients following BM stem cell transplantation [64]. Bone marrow-derived mesenchymal cells (MSCs) have been suggested to play a role in myocardial scarring [64]. Skeletal myoblasts have been associated with arrhythmias and have failed to establish gap junctions with native myocardial cells [64]. Furthermore, the efficacy of these cells in repairing damaged myocardium in clinical settings is still not clear partially due to the lack of protocol standardization as well as the use of adjunct treatment. Different diseases, cell types, cell numbers, routes of cell delivery, end point measurements, and the small number of patients included in these studies make it difficult to draw conclusions about the efficacy of stem cell therapy. Larger clinical trials are now underway to assess the risks and benefits of cell-transplantation using stem cells from BM and skeletal muscle [65].

Another emerging source of stem cells is human umbilical CB. CB has the advantage of being readily available. Numerous CB banks already exist and their number is on the rise [64, 66]. CB is obtained by a non-invasive procedure, and contains a larger portion of immature and non-committed cells than BM. Stem cells derived from CB are expandable ex vivo, appear to be more resistant to apoptosis and the risk of transmission of infection is low [64, 67]. In addition, transplantation of CB cells is associated with a lower incidence and risk of graft-versus-host disease [68, 69]. Similar to previous studies that reported beneficial effects of stem cells isolated from BM and skeletal muscle, CB stem cells also show promise for cardiac repair [1, 3-9, 10¬12, 14, 15, 17-23, 25, 27-29]. Over four thousand CB transplants worldwide have been performed for the treatment of other diseases such as leukemia and immune deficiencies [70]. In contrast, to date, no clinical trials using CB-derived stem cells for transplant after MI have been reported.

The following is an update on recent clinical trials that used BM and skeletal muscle stem cells and preclinical studies that used CB cells to repair the injured myocardium. The emphasis is to evaluate CB as a potential and practical source of stem cells for heart repair after MI.

SKELETAL STEM CELLS

Being the first cell type used clinically, it seems logical to start by discussing the use of skeletal myoblasts, or skeletal muscle satellite cells, as cell therapy after MI. The advantages of these cells are that they are readily available from muscle biopsies, they are contractile cells, and they can be expanded ex vivo before delivery into the myocardium. Moreover, they appear to have an increased resistance to ischemia [55, 71]. Cell transplantation was usually performed concomitant to revascularization or in patients with previous revascularization [1, 2, 4-6]. Most of the studies used direct injection as the delivery route [1-4]. The number of patients in each study ranged from five to 30 and patients were followed up from 68 days to four years. Except for one study, transplantation of satellite cells was shown to improve left ventricular ejection fraction (LVEF) in all recent clinical studies [1, 3-6].
Several of these studies showed improvement in New York Heart Association (NYHA) class. Interestingly, Pagani et al. showed enhanced angiogenesis after cell transplantation, but they did not measure cardiac function or ventricular remodeling. Unfortunately, it appears that the incidence of arrhythmia and ventricular tachycardia, necessitating the implementation of prophylactic amiodarone or implanted cardioverter defibrillator as an adjunct treatment, is commonplace among these trials [2-6]. Further undermining the clinical use of skeletal myoblasts is the reported lack of cardiomyogenesis and electrical coupling with native cardiac cells that would be necessary to maintain a healthy and functioning heart [55, 72]. Detailed descriptions of these most recent clinical studies using skeletal muscle satellite cells are included in Table 1 (not shown).

[It is not surprising to this reader that the inadequacy of skeletal muscle donor cells is found to be inadequate for maintaining normal cardiac contractility.  Even though contraction of skeletal muscle, smooth muscle, and heart muscle share a basic motif involving CaMKII, the generation of a calcium spark triggering contraction involves a specific relationship between CaMKIIδ and the RyR2 receptor.   CaMKIIδ is specific to the cardiomyocyte.  The other consideration is that the heart is a syncytium, and it has a relationship to neurohumoral control, distinctly different than that in skeletal muscle  This is perhaps the most telling observation in the observed lack of cardiomyogenesis and electrical coupling with native cardiac cells that would be necessary to maintain a healthy and functioning heart [55, 72]].

BM CLINICAL TRIALS

To date, only small-scale clinical trials, including five to 69 patients, have been performed using bone marrow-derived stem cells (BM-SCs) for transplantation. Three different types of BM-SCs are typically used in recent clinical trials, namely un-fractionated MNCs, CD34+ cells and MSCs. These cells were proposed to treat acute or old MI as well as heart failure [7-21]. Intracoronary injection is the delivery route of choice for these cells [7-9, 14-21]. Revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) is commonly used concomitant to cell treatment [13, 15, 16, 18-21]. Several recent trials purported improvement in cardiac function and/or ventricular remodeling three to 12 months after cell treatment [7-11, 15, 17, 18-21]. Some of these studies reported additional enhancement in clinical parameters such as

  • end diastolic (EDV),
  • end systolic volume (ESV)
  • and/or myocardial perfusion [7-9, 10, 17-20].

A small number of studies reported no benefits from BM transplantation [12-14, 16]. In one study, bone marrow transplantation was complicated by coronary artery re-occlusion [21]. The primary endpoint of most of these trials was to assess the safety and feasibility of BM-SC transplantation as a treatment for ischemic heart disease, however these studies are underpowered. In addition, the efficacy of bone marrow cell therapy is difficult to ascertain from clinical studies, at least in part, due to common utilization of adjunct therapy such as revascularization. More detailed descriptions of bone marrow clinical studies are found in Tables 2-5 (not shown).

MOBILIZATION OF BM-DERIVED CELLS

Since transplantation of autologous BM-SCs leads to improvement in cardiac function, mobilization of BM-SCs using cytokines to increase the number of circulating cells was utilized in succeeding studies. Granulocyte colony stimulating factor (G-CSF) is the most common cytokine used to mobilize BM-SCs in clinical studies [22-31]. The feasibility and safety of G-CSF has been reported by several investigators. The number of patients in the G-CSF studies ranged from five to 114 and they were followed for up to 52 weeks. Clinical studies in the last three years have shown that cardiac function improved in about half of the trials using G-CSF to mobilize BM-SCs [22, 23, 27-29]. The remaining half of G-CSF studies reported no effects on cardiac function [24-26, 30, 31]. In one study, an unexpected reduction in LVEF was reported [31]. Adverse effects of G-CSF treatment were reported in almost all the recent clinical studies [22, 24-27, 29, 31]. Detailed descriptions of G-CSF stud¬ies are shown in Tables 6-7.

HUMAN UMBILICAL CORD BLOOD: NO LONGER A WASTE PRODUCT

Amidst the flurry of clinical studies utilizing BM and skeletal muscle SCs, it is a wonder why no trials are reported using CB cell transplantation in humans. However, several pre-clinical studies using various animal models demonstrated the potential use of CB stem cells for cardiac repair after MI [32-40]. Conserved commonalities of cardiac function improvement exist in these studies despite dissimilarity of protocols used [32-40]. The following is a description of the pre-clinical studies which used different subsets of CB-derived stem cells to treat MI. In this review, the pre-clinical studies are categorized according to the type of stem cell administered.

We first start with studies that used CB-derived MNCs. Ma et al. reported that intravenous injection of six million CB-MNCs into non-obese diabetic severe combined immunodeficiency (NOD/SCID) mice 24 h post-MI resulted in an increase in capillary density and decrease in both infarct size and collagen deposition three weeks after treatment [38]. No myogenesis was observed. Human DNA was identified in 10 out of the 19 mice that underwent induction of MI. Direct myocardial injection of one-sixth of the amount of cells used in the above study in rats also reduced infarct size and increased both ventricular wall thickness and LVdP/dt and ejection fraction up to six months after treatment [34].

Similar to CB-MNCs, transplantation of two hundred thousand CD34+ cells, a subset of MNCs, within 20 min after MI

  • increased vascular density,
  • reduced LV dilation, and
  • improved cardiac function four weeks after treatment [35].

However, only about one percent of the injected cells were incorporated into the vessels of the rat myocardium, which suggests that angiogenic factors released by these cells may contribute to the observed angiogenesis [35]. A subset of CD34+, CD34+ KDR+ cell fraction, was proposed to be the subset of cells responsible for angiogenesis induction and improvement in cardiac function after treatment with either MNCs or CD34+ cells [32]. Two hundred thousand of either CD34+ or MNCs, or two thousand of either CD34+ KDR+ or CD34+ KDR- cells were injected in a NOD/SCID mouse model of MI. Compared to transplantation of MNCs or PBS, CD34+ cells

  • increased LVdP/dt,
  • decreased LV end diastolic pressure and
  • infarct size up to five months after MI.

Treatment with two thousand CD34+KDR+ cells, which is two log less than the number of CD34+ cells, resulted in more
angiogenesis compared to either MNC or CD34+ [32].

An immature subset of CB-MNCs, CD133+ cells, were also reported to improve cardiac function after transplantation into MI mice [37]. One to two million CD133+ cells were intravenously injected into athymic nude rats seven days after MI. Four weeks after transplantation,

  • reduction in both scar thinning and
  • LV systolic dilation, and
  • increase in LV fractional shortening were observed.

In contrast to other studies, vessel density did not differ between the cell-treated and control rats [37]. Similarly, transplantation of a subset of these immature CD133+ cells, CD34+ CD133+ cells, into a mouse model of hindlimb ischemia resulted in angiogenesis induction [40]. Transplantation of one hundred thousand CD34+ CD133+ cells into ischemic limbs of immunosup-pressed mice increased both vessel and muscle fiber densities fourteen days after injection. In contrast, administration of CD34+ cells resulted in increased vessel density only. Neither of these findings was observed after administration of CD34- cells [40].

An alternative subset of progenitor cells, called endothelial progenitor cells (EPCs) from either CB or adult peripheral blood (PB), was also shown to induce angiogenesis in ischemic hindlimb [39]. EPCs were derived from MNC CD34+ cells and identified in culture as attaching cells that exhibit spindle-shape. These cells

  1. incorporated acetylated-low density lipoprotein,
  2. released nitric oxide, and
  3. expressed KDR, VE-cadherin, CD31, and vW factor and CD45-.

Not only were the CB-derived EPCs more abundant (10 fold increase) than those derived from PB, they also further in-creased capillary density when injected into ischemic tissue [39].

Finally, another CB-derived cell subset, denoted as human unrestricted somatic stem cells (USSCs), was shown to engraft in the infarcted heart and improve cardiac perfusion [36]. USSCs were defined as negative for the following surface markers:

  • CD14, CD31, CD33, CD34, CD45, CD56, CD133 and human leukocyte antigen class II and
  • positive for CD13, CD29, CD44, and CD49e.

In a porcine model of MI, one hundred million USSCs were directly injected into the infarcted heart four weeks after MI.

  1. Regional perfusion,
  2. LVEF,
  3. scar thickness, and
  4. wall motion increased four weeks after transplantation [36].

In addition to cell transplantation alone, the combination of gene and cell therapy was shown to be a potential treatment for MI [33]. For example,

CD34+ cells transduced with the adeno associated viral vector that encoded either human angiopieotin-1 or vascular endothelial growth factor (VEGF) were intramyocardially injected in a mouse model of MI. Improved cardiac function and increased capillary density were observed with CD34+ cells alone.

However, exaggerated improvements were obtained with the combined therapy of CD34+ cells transfected with Angiopieotin-1 and or VEGF. Compared with CD34+ treatment alone,

  • the combined therapy further increased capillary density and decreased infarct size [33].

Taken together, based on the pre-clinical studies, a common feature of transplantation of human CB-derived cells is

  • induction of angiogenesis and cardiac function improvement in animal models of ischemia.

Myogenesis does not seem to be a mechanism of the beneficial effects of CB transplantation.

Compared with adult stem cells, CB cell treatment has limitations. The practical and crucial difference between stem cells obtained from adult human donors and from CB is quantitatively, not qualitatively based. It is uncommon that more than several million stem cells can be isolated from CB. That amount may be too small for transplantation to an adult. Children appear to be ideal recipients when utilizing this source of stem cells since they are smaller patients and require fewer cells per kilogram of body weight [71]. However, ex vivo expansion of these cells may overcome this limitation [73, 74]. There is another concern that the use of CB for transplantation presents a higher risk of transmitting opportunistic infections [75]. The human herpes viruses are common pathogens found in transplant recipients. Currently, it is routine to test for the presence of anti-cytomegalovirus immunoglobin M. However, screening prospective CB donors for these pathogens reduces the risk of transmission of infection [75].

(Tables from published document are to be viewed in that document.)

CONCLUSIONS

Although early clinical studies suggest that bone marrow and skeletal myoblast transplantation into the infarcted heart improves cardiac perfusion and function, there is an urgent need for large randomized double-blinded clinical trials that assess the overall efficacy of cell-based therapy. In addition, little is known about the mechanisms by which stem cells render their positive effects. Cardiac regeneration by bone marrow cells is an obvious mechanism. However, a small number of experimental studies have purported the occurrence of myocardial regeneration by bone marrow cells. Furthermore, substantial evidence demonstrates that cell types other than cardiomyocytes improve cardiac function, suggesting that the beneficial effects of cell therapy may be independent of cardiac regeneration [76-89]. Enhanced vascularization, on the other hand, is a common finding after bone marrow cell transplantation. Cell engrafment to the vascular wall as well as angiogenic factors released by transplanted cells may be responsible for the enhanced vascularization. Obviously, there remain a considerable number of unanswered questions that must be addressed in basic science laboratories before stem cell therapy becomes standard practice. For example, what are the mechanisms of improvement in cardiac function? Which cell type is best-suited for transplantation? What is the optimal cell concentration that should be used for transplant and what is the most effective route of delivery?

The target patient population which would draw clinical benefit from cell-based therapy must also be defined and the optimal time of injection after the onset of infarction has to be determined. Currently, it is difficult to assess the efficacy of stem cell treatment of MI. This is in part due to lack of standardization among clinical as well as pre-clinical studies. Therefore, in order to accomplish these objectives, there is great need for communication among the various research groups concerned with stem cells and clinical studies.

Here we add yet another source of stem cells, namely the umbilical CB. This source of stem cells had many advantages mentioned in the preceding sections. In addition, pre-clinical studies indicate the efficacy of CB cells in myocardial repair. However, the fate and benefits of these cells need to be tested in clinical settings.

REFERENCES

[1]  Herreros J, Prosper F, Perez A, Gavira JJ, Garcia-Velloso MJ, Barba J, et al. Autologous intramyocardial injection of cultured skeletal muscle-derived stem cells in patients with non-acute myocardial infarction. Eur Heart J 2003; 24: 2012-20.

[2]  Pagani FD, DerSimonian H, Zawadzka A, Wetzel K, Edge AS, Jacoby DB, et al. Autologous skeletal myoblasts transplanted to ischemia-damaged myocardium in humans. Histological analysis of cell survival and differentiation. J Am Coll Cardiol 2003; 41: 879-88.

[3]  Smits PC, van Geuns RJ, Poldermans D, Bountioukos M, Onder-water EE, Lee CH, et al. Catheter-based intramyocardial injection of autologous skeletal myoblasts as a primary treatment of ischemic heart failure: clinical experience with six-month follow-up. J Am Coll Cardiol 2003; 42: 2063-9.

[4]  Dib N, Michler RE, Pagani FD, Wright S, Kereiakes DJ, Lengerich R, et al. Safety and feasibility of autologous myoblast transplantation in patients with ischemic cardiomyopathy: four-year follow-up. Circulation 2005; 112: 1748-55.

[5]  Siminiak T, Kalawski R, Fiszer D, Jerzykowska O, Rzezniczak J, Rozwadowska N, et al. Autologous skeletal myoblast transplantation for the treatment of postinfarction myocardial injury: phase I clinical study with 12 months of follow-up. Am Heart J 2004; 148: 531-7.

[6]  Siminiak T, Fiszer D, Jerzykowska O, Grygielska B, Rozwadowska N, Kalmucki P, et al. Percutaneous trans-coronary-venous trans-plantation of autologous skeletal myoblasts in the treatment of post-infarction myocardial contractility impairment: the POZNAN trial. Eur Heart J 2005; 26: 1188-95.

[7]  Assmus B, Schachinger V, Teupe C, Britten M, Lehmann R, Dobert N, et al. Transplantation of Progenitor Cells and Regeneration Enhancement in Acute Myocardial Infarction (TOPCARE-AMI). Circulation 2002; 106: 3009-17.

[8]  Schachinger V, Assmus B, Britten MB, Honold J, Lehmann R, Teupe C, et al. Transplantation of progenitor cells and regeneration enhancement in acute myocardial infarction: final one-year results of the TOPCARE-AMI Trial. J Am Coll Cardiol 2004; 44: 1690-9.

[9]  Britten MB, Abolmaali ND, Assmus B, Lehmann R, Honold J, Schmitt J, et al. 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 2003; 108: 2212-8.

[10]  Perin EC, Dohmann HFR, Borojevic R, Silva SA, Sousa ALS, Mesquita CT, et al. Transendocardial, autologous bone marrow cell transplantation for severe, chronic ischemic heart failure. Circulation 2003; 107: 2294–302.

Human umbilical cord blood stem cells, myocardial infarction (and stroke)

Nathan Copeland, David Harris and Mohamed A Gaballa
Nathan Copeland, Research Associate and Medical Student, University of Arizona Medical School, Tucson, Arizona; David Harris, Professor of Microbiology and Immunology, University of Arizona, Tucson, Arizona; Mohamed A Gaballa, Director, Center for Cardiovascular Research, Sun Health Research Institute, Sun City, Arizona; Section Chief of Basic Science, Cardiology Section, Banner GoodSam Medical Center, Phoenix, Arizona
Clinical Medicine 2009, Vol 9, No 4: 342–5

ABSTRACT – Myocardial infarction (MI) and stroke are the first and third leading causes of death in the USA accounting for more than 1 in 3 deaths per annum. Despite interventional and pharmaceutical advances, the number of people diagnosed with heart disease is on the rise. Therefore, new clinical strategies are needed. Cell-based therapy holds great promise for treatment of these diseases and is currently under extensive preclinical as well as clinical trials. The source and types of stem cells for these clinical applications are questions of great interest. Human umbilical cord blood (hUCB) appears to be a logical candidate as a source of cells. hUCB is readily available, and presents little ethical challenges. Stem cells derived from hUCB are multipotent and immunologically naive. Here is a critical literature review of the beneficial effects of hUCB cell therapy in preclinical trials.
KEY WORDS: animal models, cerebral infarction, myocardial infarction, stem cells, umbilical cord blood

Introduction

The study of stem cell therapies to address some of the most daunting medical challenges, including heart disease and stroke, has advanced steadily over the last three years. The majority of preclinical studies of stem cells as a potential therapy for either myocardial or cerebral ischaemia were positive on average. Small clinical trials, however, show either no or modest improvement in cardiac function after myocardial infarction (MI). Currently, there are two major types of autologous cells that are clinically used for MI and stroke. The first is skeletal myoblasts, harvested from skeletal muscle. These cells can be expanded in culture. Positive outcomes were recently reported in a phase 1 clinical trial using catheter-based injection of myoblasts to the endocardium (CAUSMIC, American Heart Association (AHA) Scientific Sessions 2007). The second is bone marrow cells (BMCs). Intracoronary injection of BMCs improve global left ventricular function (IC-BMC, AHA Scientific Sessions 2007). However, direct injection of BMC administration into scarred myocardium does not alter cardiac contractility of the injured area (IC/IM-BMC, AHA Scientific Sessions 2007). The effects of stem cell therapy can only be addressed using clinical trials that:

•             are randomised, blinded, placebo controlled and adequately sized

•             use standardisation of autologous stem cell processing protocols

•             use robust endpoints of efficacy and safety

•             ensure that follow-up is complete and of adequate duration.

It is becoming clear that realisation of the full potential of the therapeutic benefit of stem cells will require understanding the biology of these undifferentiated cells. A successful therapy will require a source with plentiful supply of multipotent stem cells with minimal or no immune rejection. Several sources of stem cells were explored such as

  • adipose tissue,1–3
  • cardiac tissue,4
  • skeletal muscle biopsies,5,6 and
  • hUCB.

Whether these subpopulations of cells are best suited to treat a disease is still unanswered.

Currently, the only confirmed source for totipotential cells is embryonic. However, there are ethical and scientific obstacles to unbridled use of such cells. For clinical application, autologous adult stem cells are the obvious choice. To date, only adult stem cells derived from a patient’s own bone marrow are being used in clinical trials.

Autologous BMC therapy is not without problems. The majority of instances of MI and cerebral ischaemia (CI) occur in the elderly. Since the quantity and function of BMCs decrease with age, an allogeneic younger donor may be used to source BMCs. This may hinder the efficiency of such a treatment and suffer rejection, therefore another source of stem cells is needed.

Cryopreserved stem cells derived from human leukocyte antigen (HLA)-matched and unmatched unrelated donor hUCB were realised as a sufficient source of transplantable hematopoietic stem cells with high donor-derived engraftment and low risk of refractory acute graft-versus-host disease. However, the use of hUCB cells as treatment for either MI or CI has only been recently investigated in preclinical models.

There are several outstanding review articles on stem cells derived from cord blood in MI7–11 and stroke.12–17 This article adds depth to the debate by providing an updated review as well as presenting an integrated overview of studies involving MI and CI cell-based therapy. In the preparation of this review, every effort was made to include all relevant publications since 2005. Due to space limitations, the number of articles cited has been limited.

Cardiovascular disease

Since 2005, several studies have explored the use of various sub-populations of hUCB stem cells for regenerative therapy. Five types of UCB-derived stem cells were investigated: umbilical cord derived stem (UCDS), unrestricted somatic stem cells (USSC), mononuclear progenitor cells (MNCs), CD133+ and CD34+ subpopulations. The experimental parameters of the studies varied. The majority of studies, however, were performed using the rat animal model and utilising the left antero-lateral descending (LAD) coronary artery ligation model of MI with intramyocardial injection of the stem cells. The laboratory used a similar model to determine the efficacy of stem cell derived from hUCB to improve cardiac function after ischemia and reperfusion. The data indicated that intracoronary administration of mononuclear or CD34+ cells derived from hUCB improved cardiac function after MI by inducing neovascularisation and retarding left ventricular (LV) remodelling.37

The majority of reported studies using hUCB cells showed improvement in the outcomes.18–25 Cardiac functional improvements were almost universally reported as evaluated by:

  • increased ejection fraction;
  • improved wall motion;
  • lowered LV end-diastolic pressure; and
  • increased cardiac contraction as determined by the maximum slope of LV pressure.18–21,23–25

There were conflicting reports on the effects of stem cells on LV fractional shorting. One study reported improved shortening while another reported that BM but not UCB cells produced improved shortening.22,23 Improvements in

  • myocardial perfusion, evaluated by increased capillary density, were repeatedly demonstrated as were
  • reductions in infarct size and the number of apoptotic cells.18–25

Retardation or reduction in LV remodelling were also reported.18,21,22 Although the vast majority of studies showed positive outcomes, HLA matching and further study are still needed before UCB stem cell therapies can become safe and effective treatments in humans. A prime example of the need for further elucidation of these emerging therapies can be illustrated by the findings in a study by Moelker.26 This study used intracoronary administration of unrestricted somatic stem cells (USSCs) in a balloon left circumflex artery (LCX) occlusion ischaemia-reperfusion porcine model of MI. They found that treatment did not improve outcome and actually increased infarct size. Their histological analysis revealed that the injected cells worsened the infarct by obstructing vessels downstream.

Furthermore, the mechanisms of the observed benefits of UCB stem cell therapy in MI are under investigation:

  • improved myocardial perfusion,
  • attenuation of cardiac remodelling,
  • reduction of inflammatory responses by
    • limiting expression of TNF-a, MCP-1, MIP and INF–y, and cardiac regeneration.18–5

Tissue regeneration may be mediated by incorporation of delivered cells in the target tissue.18–21,23 An in vitro study confirmed that mononuclear cells were migrated toward homogenised infarcted myocardium and that the greatest migration occurred at two and 24 hours post-MI.20 Paracrine effect, ie the delivered cells release factors that promote neovascularisation, was also reported. Indeed, the study laboratory has shown that hUCB cells release angiogenic factors in vitro under hypoxic conditions. The data are consistent with a previous report that showed

  • increased expression of VEGF 164 and 188 accompanied by
  • angiogenesis and improved remodelling after administration of hUCB mononuclear cells into the myocardium.21

Identifying subpopulations of progenitor cells with the highest potential for tissue repair is another unanswered ques¬tion prior to widespread application of this therapy in clinical settings. Previous studies showed that UCB-derived endothe¬lial progenitor cells (EPC) to be a promising subset of stem cells for treatment of MI; however their number may be insufficient to treat adult patients. This problem can be addressed by expanding these cells in culture prior to transplant. Techniques are being developed to culture clinically significant quantities (60 population doublings) of EPCs from UBC CD.25 Transplantation of these expanded cells improved ejection fraction (EF) and vascular density in vivo, demonstrating that such a culture method may be a viable option to produce EPCs for future use in humans. Another study evaluated the use of gene therapies in conjunction with UCB stem cell therapy.24 CD34+ cells were transfected with AAV-Ang1 and/or AAV-VEGF 165. The gene-modified stem cells resulted in greater increases in capillary density and cardiac performance along with larger reduction in infarct size compared to CD34+ cell therapy alone.

References

1 Valina C, Pinkernell K, Song YH et al. Intracoronary administration of autologous adipose tissue-derived stem cells improves left ventricular function, perfusion, and remodelling after acute myocardial infarction. Eur Heart J 2007;28:2667–77.

2 Zhang DZ, Gai LY, Liu HW et al. Transplantation of autologous adipose-derived stem cells ameliorates cardiac function in rabbits with myocardial infarction. Chin Med J (Engl) 2007;120:300–7.

4 Hoogduijn MJ, Crop MJ, Peeters AM et al. Human heart, spleen, and perirenal fat-derived mesenchymal stem cells have immunomodulatory capacities. Stem Cells Dev 2007;16:597–604.

5 Payne TR, Oshima H, Okada M et al. A relationship between vascular endothelial growth factor, angiogenesis, and cardiac repair after muscle stem cell transplantation into ischemic hearts. J Am Coll Cardiol 2007;50:1677–84.

6 Herreros J, Prósper F, Perez A et al. Autologous intramyocardial injection of cultured skeletal muscle-derived stem cells in patients with non-acute myocardial infarction. Eur Heart J 2003;24:2012–20.

7 Goldberg JL, Laughlin MJ, Pompili VJ. Umbilical cord blood stem cells: implications for cardiovascular regenerative medicine. J Mol Cell Cardiol 2007;42:912–20.

8  Wu KH, Yang SG, Zhou B et al. Human umbilical cord derived stem cells for the injured heart. Med Hypotheses 2007;68:94–7.

9 Zhang L, Yang R, Han ZC. Transplantation of umbilical cord blood-derived endothelial progenitor cells: a promising method of therapeutic revascularisation. Eur J Haematol 2006;76:1–8.

18 Wu KH, Zhou B, Yu CT et al. Therapeutic potential of human umbil¬ical cord derived stem cells in a rat myocardial infarction model. Ann Thorac Surg 2007;83:1491–8.

19 Kim BO, Tian H, Prasongsukarn K et al. Cell transplantation improves ventricular function after a myocardial infarction: a preclinical study of human unrestricted somatic stem cells in a porcine model. Circulation 2005;112:I96–104.

20 Henning RJ, Burgos JD, Ondrovic L et al. Human umbilical cord blood progenitor cells are attracted to infarcted myocardium and sig-nificantly reduce myocardial infarction size. Cell Transplant 2006;15:647–58.

21 Hu CH, Wu GF, Wang XQ et al. Transplanted human umbilical cord blood mononuclear cells improve left ventricular function through angiogenesis in myocardial infarction. Chin Med J (Engl)  2006;119:1499–506.

22 Ma N, Ladilov Y, Moebius JM et al. Intramyocardial delivery of human CD133+ cells in a SCID mouse cryoinjury model: Bone marrow vs. cord blood-derived cells. Cardiovasc Res 2006;71:158–69.

23 Leor J, Guetta E, Feinberg MS et al. Human umbilical cord blood-derived CD133+ cells enhance function and repair of the infarcted myocardium. Stem Cells 2006;24:772–80.

24 Chen HK, Hung HF, Shyu KG et al. Combined cord blood stem cells and gene therapy enhances angiogenesis and improves cardiac perfor-mance in mouse after acute myocardial infarction. Eur J Clin Invest 2005;35:677–86.

 

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Demonstration of a diagnostic clinical laboratory neural network agent applied to three laboratory data conditioning problems

Izaak Mayzlin                                                                        Larry Bernstein, MD

Principal Scientist, MayNet                                            Technical Director

Boston, MA                                                                          Methodist Hospital Laboratory, Brooklyn, NY

Our clinical chemistry section services a hospital emergency room seeing 15,000 patients with chest pain annually.  We have used a neural network agent, MayNet, for data conditioning.  Three applications are – troponin, CKMB, EKG for chest pain; B-type natriuretic peptide (BNP), EKG for congestive heart failure (CHF); and red cell count (RBC), mean corpuscular volume (MCV), hemoglobin A2 (Hgb A2) for beta thalassemia.  Three data sets have been extensively validated prior to neural network analysis using receiver-operator curve (ROC analysis), Latent Class Analysis, and a multinomial regression approach.  Optimum decision points for classifying using these data were determined using ROC (SYSTAT, 11.0), LCM (Latent Gold), and ordinal regression (GOLDminer).   The ACS and CHF studies both had over 700 patients, and had a different validation sample than the initial exploratory population.  The MayNet incorporates prior clustering, and sample extraction features in its application.   Maynet results are in agreement with the other methods.

Introduction: A clinical laboratory servicing a hospital with an  emergency room seeing 15,000 patients with chest pain to produce over 2 million quality controlled chemistry accessions annually.  We have used a neural network agent, MayNet, to tackle the quality control of the information product.  The agent combines a statistical tool that first performs clustering of input variables by Euclidean distances in multi-dimensional space. The clusters are trained on output variables by the artificial neural network performing non-linear discrimination on clusters’ averages.  In applying this new agent system to diagnosis of acute myocardial infarction (AMI) we demonstrated that at an optimum clustering distance the number of classes is minimized with efficient training on the neural network. The software agent also performs a random partitioning of the patients’ data into training and testing sets, one time neural network training, and an accuracy estimate on the testing data set. Three examples to illustrate this are – troponin, CKMB, EKG for acute coronary syndrome (ACS); B-type natriuretic peptide (BNP), EKG for the estimation of ejection fraction in congestive heart failure (CHF); and red cell count (RBC), mean corpuscular volume (MCV), hemoglobin A2 (Hgb A2) for identifying beta thalassemia.  We use three data sets that have been extensively validated prior to neural network analysis using receiver-operator curve (ROC analysis), Latent Class Analysis, and a multinomial regression approach.

In previous studies1,2 CK-MB and LD1 sampled at 12 and 18 hours postadmission were near-optimum times used to form a classification by the analysis of information in the data set. The population consisted of 101 patients with and 41 patients without AMI based on review of the medical records, clinical presentation, electrocardiography, serial enzyme and isoenzyme  assays, and other tests. The clinical or EKG data, and other enzymes or sampling times were not used to form a classification but could be handled by the program developed. All diagnoses were established by cardiologist review. An important methodological problem is the assignment of a correct diagnosis by a “gold standard” that is independent of the method being tested so that the method tested can be suitably validated. This solution is not satisfactory in the case of myocardial infarction because of the dependence of diagnosis on a constellation of observations with different sensitivities and specificities. We have argued that the accuracy of diagnosis is  associated with the classes formed by combined features and has greatest uncertainty associated with a single measure.

Methods:  Neural network analysis is by MayNet, developed by one of the authors.  Optimum decision points for classifying using these data were determined using ROC (SYSTAT, 11.0), LCM (Latent Gold)3, and ordinal regression (GOLDminer)4.   Validation of the ACS and CHF study sets both had over 700 patients, and all studies had a different validation sample than the initial exploratory population.  The MayNet incorporates prior clustering, and sample extraction features in its application.   We now report on a new classification method and its application to diagnosis of acute myocardial infarction (AMI).  This method is based on the combination of clustering by Euclidean distances in multi-dimensional space and non-linear discrimination fulfilled by the Artificial Neural Network (ANN) trained on clusters’ averages.   These studies indicate that at an optimum clustering distance the number of classes is minimized with efficient training on the ANN. This novel approach to ANN reduces the number of patterns used for ANN learning and works also as an effective tool for smoothing data, removing singularities,  and increasing the accuracy of classification by the ANN. The studies  conducted involve training and testing on separate clinical data sets, which subsequently achieves a high accuracy of diagnosis (97%).

Unlike classification, which assumes the prior definition of borders between classes5,6, clustering procedure includes establishing these borders as a result of processing statistical information and using a given criteria for difference (distance) between classes.  We perform clustering using the geometrical (Euclidean) distance between two points in n-dimensional space, formed by n variables, including both input and output variables. Since this distance assumes compatibility of different variables, the values of all input variables are linearly transformed (scaled) to the range from 0 to 1.

The ANN technique for readers accustomed to classical statistics can be viewed as an extension of multivariate regression analyses with such new features as non-linearity and ability to process categorical data. Categorical (not continuous) variables represent two or more levels, groups, or classes of correspondent feature, and in our case this concept is used to signify patient condition, for example existence or not of AMI.

The ANN is an acyclic directed graph with input and output nodes corresponding respectively to input and output variables. There are also “intermediate” nodes, comprising so called “hidden” layers.  Each node nj is assigned the value xj that has been evaluated by the node’s “processing” element, as a non-linear function of the weighted sum of values xi of nodes ni, connected with nj by directed edges (ni, nj).

xj = f(wi(1),jxi(1) + wi(2),jxi(2) + … + wi(l),jxi(l)),

where xk is the value in node nk and wk,j is the “weight” of the edge (nk, nj).  In our research we used the standard function f(x), “sigmoid”, defined as f(x)=1/(1+exp(-x)).  This function is suitable for categorical output and allows for using an efficient back-propagation algorithm7 for calculating the optimal values of weights, providing the best fit for learning set of data, and eventually the most accurate classification.

Process description:  We implemented the proposed algorithm for diagnosis of AMI. All the calculations were performed on PC with Pentium 3 Processor applying the authors’ unique Software Agent Maynet. First, using the automatic random extraction procedure, the initial data set (139 patients) was partitioned into two sets — training and testing.  This randomization also determined the size of these sets (96 and 43, respectively) since the program was instructed to assign approximately 70 % of data to the training set.

The main process consists of three successive steps: (1) clustering performed on training data set, (2) neural network’s training on clusters from previous step, and (3) classifier’s accuracy evaluation on testing data.

The classifier in this research will be the ANN, created on step 2, with output in the range [0,1], that provides binary result (1 – AMI, 0 – not AMI), using decision point 0.5.

In this demonstartion we used the data of two previous studies1,2 with three patients, potential outliers, removed (n = 139). The data contains three input variables, CK-MB, LD-1, LD-1/total LD, and one output variable, diagnoses, coded as 1 (for AMI) or 0 (non-AMI).

Results: The application of this software intelligent agent is first demonstrated here using the initial model. Figures 1-2 illustrate the history of training process. One function is the maximum (among training patterns) and lower function shows the average error. The latter defines duration of training process. Training terminates when the average error achieves 5%.

There was slow convergence of back-propagation algorithm applied to the training set of 96 patients. We needed 6800 iterations to achieve the sufficiently small (5%) average error.

Figure 1 shows the process of training on stage 2. It illustrates rapid convergence because we deal only with 9 patterns representing the 9 classes, formed on step 1.

Table 1 illustrates the effect of selection of maximum distance on the number of classes formed and on the production of errors. The number of classes increased with decreasing distance, but accuracy of classification does not decreased.

The rate of learning is inversely related to the number of classes. The use of the back-propagation to train on the entire data set without prior processing is slower than for the training on patterns.

     Figures 2 is a two-dimensional projection of three-dimensional space of input variables CKMB and LD1 with small dots corresponding to the patterns and rectangular as cluster centroids (black – AMI, white – not AMI).

     We carried out a larger study using troponin I (instead of LD1) and CKMB for the diagnosis of myocardial infarction (MI).  The probabilities and odds-ratios for the TnI scaled into intervals near the entropy decision point are shown in Table 2 (N = 782).  The cross-table shows the frequencies for scaled TnI results versus the observed MI, the percent of values within MI, and the predicted probabilities and odds-ratios for MI within TnI intervals.  The optimum decision point is at or near 0.61 mg/L (the probability of MI at 0.46-0.6 mg/L is 3% and the odds ratio is at 13, while the probability of MI at 0.61-0.75 mg/L is 26% at an odds ratio of 174) by regressing the scaled values.

     The RBC, MCV criteria used were applied to a series of 40 patients different than that used in deriving the cutoffs.  A latent class cluster analysis is shown in Table 3.  MayNet is carried out on all 3 data sets for MI, CHF, and for beta thalassemia for comparison and will be shown.

Discussion:  CKMB has been heavily used for a long time to determine heart attacks. It is used in conjunction with a troponin test and the EKG to identify MI but, it isn’t as sensitive as is needed. A joint committee of the AmericanCollege of Cardiology and European Society of Cardiology (ACC/ESC) has established the criteria for acute, recent or evolving AMI predicated on a typical increase in troponin in the clinical setting of myocardial ischemia (1), which includes the 99th percentile of a healthy normal population. The improper selection of a troponin decision value is, however, likely to increase over use of hospital resources.  A study by Zarich8 showed that using an MI cutoff concentration for TnT from a non-acute coronary syndrome (ACS) reference improves risk stratification, but fails to detect a positive TnT in 11.7% of subjects with an ACS syndrome8. The specificity of the test increased from 88.4% to 96.7% with corresponding negative predictive values of 99.7% and 96.2%. Lin et al.9 recently reported that the use of low reference cutoffs suggested by the new guidelines results in markedly increased TnI-positive cases overall. Associated with a positive TnI and a negative CKMB, these cases are most likely false positive for MI. Maynet relieves this and the following problem effectively.

Monitoring BNP levels is a new and highly efficient way of diagnosing CHF as well as excluding non-cardiac causes of shortness of breath. Listening to breath sounds is only accurate when the disease is advanced to the stage in which the pumping function of the heart is impaired. The pumping of the heart is impaired when the circulation pressure increases above the osmotic pressure of the blood proteins that keep fluid in the circulation, causing fluid to pass into the lung’s airspaces.  Our studies combine the BNP with the EKG measurement of QRS duration to predict whether a patient has a high or low ejection fraction, a measure to stage the severity of CHF.

We also had to integrate the information from the hemogram (RBC, MCV) with the hemoglobin A2 quantitation (BioRad Variant II) for the diagnosis of beta thalassemia.  We chose an approach to the data that requires no assumption about the distribution of test values or the variances.   Our detailed analyses validates an approach to thalassemia screening that has been widely used, the Mentzer index10, and in addition uses critical decision values for the tests that are used in the Mentzer index. We also showed that Hgb S has an effect on both Hgb A2 and Hgb F.  This study is adequately powered to assess the usefulness of the Hgb A2 criteria but not adequately powered to assess thalassemias with elevated Hgb F.

References:

1.  Adan J, Bernstein LH, Babb J. Lactate dehydrogenase isoenzyme-1/total ratio: accurate for determining the existence of myocardial infarction. Clin Chem 1986;32:624-8.

2. Rudolph RA, Bernstein LH, Babb J. Information induction for predicting acute myocardial infarction.  Clin Chem 1988;34:2031- 2038.

3. Magidson J. “Maximum Likelihood Assessment of Clinical Trials Based on an Ordered Categorical Response.” Drug Information Journal, Maple Glen, PA: Drug Information Association 1996;309[1]: 143-170.

4. Magidson J and Vermoent J.  Latent Class Cluster Analysis. in J. A. Hagenaars and A. L. McCutcheon (eds.), Applied Latent Class Analysis. Cambridge: CambridgeUniversity Press, 2002, pp. 89-106.

5. Mkhitarian VS, Mayzlin IE, Troshin LI, Borisenko LV. Classification of the base objects upon integral parameters of the attached network. Applied Mathematics and Computers.  Moscow, USSR: Statistika, 1976: 118-24.

6.Mayzlin IE, Mkhitarian VS. Determining the optimal bounds for objects of different classes. In: Dubrow AM, ed. Computational Mathematics and Applications. MoscowUSSR: Economics and Statistics Institute. 1976: 102-105.

7. RumelhartDE, Hinton GE, Williams RJ. Learning internal representations by error propagation. In:

RumelhartDE, Mc Clelland JL, eds. Parallel distributed processing.   Cambridge, Mass: MIT Press, 1986; 1: 318-62.

8. Zarich SW, Bradley K, Mayall ID, Bernstein, LH. Minor Elevations in Troponin T Values Enhance Risk Assessment in Emergency Department Patients with Suspected Myocardial Ischemia: Analysis of Novel Troponin T Cut-off Values.  Clin Chim Acta 2004 (in press).

9. Lin JC, Apple FS, Murakami MM, Luepker RV.  Rates of positive cardiac troponin I and creatine kinase MB mass among patients hospitalized for suspected acute coronary syndromes.  Clin Chem 2004;50:333-338.

10.Makris PE. Utilization of a new index to distinguish heterozygous thalassemic syndromes: comparison of its specificity to five other discriminants.Blood Cells. 1989;15(3):497-506.

Acknowledgements:   Jerard Kneifati-Hayek and Madeleine Schlefer, Midwood High School, Brooklyn, and Salman Haq, Cardiology Fellow, Methodist Hospital.

Table 1. Effect of selection of maximum distance on the number of classes formed and on the accuracy of recognition by ANN

ClusteringDistanceFactor F(D = F * R)  Number ofClasses  Number of Nodes inThe HiddenLayers  Number ofMisrecognizedPatterns inThe TestingSet of 43 Percent ofMisrecognized   
  10.90.80.7  2414135  1, 02, 03, 01, 02, 03, 0

3, 2

3, 2

121121

1

1

2.34.62.32.34.62.3

2.3

2.3

Figure 1.

Figure 2.

Table 2.  Frequency cross-table, probabilities and odds-ratios for scaled TnI versus expected diagnosis

Range Not MI MI N Pct in MI Prob by TnI Odds Ratio
< 0.45 655 2 657 2 0 1
0.46-0.6 7 0 7 0 0.03 13
0.61-0.75 4 0 4 0. 0.26 175
0.76-0.9 13 59 72 57.3 0.82 2307
> 0.9 0 42 42 40.8 0.98 30482
679 103 782 100

 

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