Arteriogenesis and Cardiac Repair: Two Biomaterials – Injectable Thymosin beta4 and Myocardial Matrix Hydrogel
Curator: Aviva Lev-Ari, PhD, RN
Thymosin beta 4 (Tβ4)
is a highly conserved, 43-amino acid acidic peptide (pI 4.6) that was first isolated from bovine thymus tissue over 25 years ago. It is present in most tissues and cell lines and is found in high concentrations in blood platelets, neutrophils, macrophages, and other lymphoid tissues. Tβ4 has numerous physiological functions, the most prominent of which being the regulation of actin polymerization in mammalian nucleated cells and with subsequent effects on actin cytoskeletal organization, necessary for cell motility, organogenesis, and other important cellular events.
Recently,
- Tβ4 was shown to be expressed in the developing heart and found to stimulate migration of cardiomyocytes and endothelial cells, promote survival of cardiomyocytes (Nature, 2004), and most recently
- to play an essential role in all key stages of cardiac vessel development: vasculogenesis, angiogenesis, and arteriogenesis (Nature 2006).
These results suggest that Tβ4 may have significant therapeutic potential in humans to protect myocardium and promote cardiomyocyte survival in the acute stages of ischemic heart disease.
RegeneRx Biopharmaceuticals, Inc. is developing Tβ4 for the treatment of patients with acute myocardial infarction (AMI). Such efforts presented will include the formulation, development, and manufacture of a suitable drug product for use in the clinic, the performance of nonclinical pharmacology and toxicology studies, and the implementation of a phase 1 clinical protocol to assess the safety, tolerability, and the pharmacokinetics of Tβ4 in healthy volunteers.
Clinical Study Data of Thymosin beta 4 Presented
Published on October 3, 2009 at 5:10 AM
REGENERX BIOPHARMACEUTICALS, INC. (NYSE Amex:RGN) today reported on several clinical studies with Thymosin beta 4 (Tβ4) presented the Second International Symposium on Thymosins in Health and Disease, in Catania, Italy. The following are synopses of the presentations:
Myocardial Development of RGN-352 (Injectable Tβ4 Peptide)
David Crockford, RegeneRx’s vice president for clinical and regulatory affairs presented an overview of the biological properties that support Tβ4’s near term and long term clinical applications. Mr. Crockford noted that special emphasis is being placed on the development of RGN-352 for the systemic (injectable) treatment of patients with ST-elevation myocardial infarction (STEMI) in combination with percutaneous coronary intervention, the current standard of care in most western countries for this common type of heart attack. The goal with RGN-352 is to prevent or repair continued damage to cardiac tissue post-heart attack, when such tissue around the damaged site remains at risk.
Dr. Dennis Ruff, vice president and medical director of ICON, and principal investigator, presented the most current results on the Phase I safety study with RGN-352 entitled, “A Randomized, Double-blind, Placebo-controlled, Dose-response Phase I Study of the Safety and Tolerability of the Intravenous Administration of Thymosin Beta 4 and its Pharmacokinetics After Single and Multiple Doses in Healthy Volunteers.” Dr. Ruff discussed key aspects of the study and concluded with, “There were no dose limiting or serious adverse events throughout the dosing period. Synthetic Tβ4 administered intravenously up to 1260 mg, and for up to 14 days, appears to be well tolerated with low incidence of adverse events and no evidence of serious adverse events.”
http://www.news-medical.net/news/20091003/Clinical-study-data-of-Thymosin-beta-4-presented.aspx
RegeneRx Receives Notice of Allowance from Chinese Patent Office for Treatment and Prevention of Heart Disease
February 7, 2013 — Rockville, Md.
RegeneRx Biopharmaceuticals, Inc. (OTC Bulletin Board: RGRX) (“the Company” or “RegeneRx”) today announced that it has received a Notice of Allowance of a Chinese patent application for uses of Thymosin beta 4 (TB4) for treating, preventing, inhibiting or reducing heart tissue deterioration, injury or damage in a subject with heart failure disease. Claims also include uses for restoring heart tissue in those subjects. The patent will expire July 26, 2026.
http://www.regenerx.com/wt/page/pr_1360265259
Active Research on Thymosins in Cardiovascular Disease Reported in 2010 and 2012 Annual Conference on Thymosins, Proceedings by NY Academy of Sciences
Use of the cardioprotectants thymosin β4 and dexrazoxane during congenital heart surgery: proposal for a randomized, double-blind, clinical trial
Neonates and infants undergoing heart surgery with cardioplegic arrest experience both inflammation and myocardial ischemia-reperfusion (IR) injury. These processes provoke myocardial apoptosis and oxygen-free radical formation that result in cardiac injury and dysfunction. Thymosin β4 (Tβ4) is a naturally occurring peptide that has cardioprotective and antiapoptotic effects. Similarly, dexrazoxane provides cardioprotection by reduction of toxic reactive oxygen species (ROS) and suppression of apoptosis. We propose a pilot pharmacokinetic/safety trial of Tβ4 and dexrazoxane in children less than one year of age, followed by a randomized, double-blind, clinical trial of Tβ4 or dexrazoxane versus placebo during congenital heart surgery. We will evaluate postoperative time to resolution of organ failure, development of low cardiac output syndrome, length of cardiac ICU and hospital stays, and echocardiographic indices of cardiac dysfunction. Results could establish the clinical utility of Tβ4 and/or dexrazoxane in ameliorating ischemia-reperfusion injury during congenital heart surgery.[1]
Cardiac repair with thymosin β4 and cardiac reprogramming factors
Heart disease is a leading cause of death in newborns and in adults. We previously reported that the G-actin–sequestering peptide thymosin β4 promotes myocardial survival in hypoxia and promotes neoangiogenesis, resulting in cardiac repair after injury. More recently, we showed that reprogramming of cardiac fibroblasts to cardiomyocyte-like cells in vivo after coronary artery ligation using three cardiac transcription factors (Gata4/Mef2c/Tbx5) offers an alternative approach to regenerate heart muscle. We have combined the delivery of thymosin β4 and the cardiac reprogramming factors to further enhance the degree of cardiac repair and improvement in cardiac function after myocardial infarction. These findings suggest that thymosin β4 and cardiac reprogramming technology may synergistically limit damage to the heart and promote cardiac regeneration through the stimulation of endogenous cells within the heart.[2]
NMR structural studies of thymosin α1 and β-thymosins
Thymosin proteins, originally isolated from fractionation of thymus tissue, represent a class of compounds that we now know are present in numerous other tissues, are unrelated to each other in a genetic sense, and appear to have different functions within the cell. Thymosin α1 (generic drug name thymalfasin; trade name Zadaxin) is derived from a precursor molecule, prothymosin, by proteolytic cleavage, and stimulates the immune system. Although the peptide is natively unstructured in aqueous solution, the helical structure has been observed in the presence of trifluoroethanol or unilamellar vesicles, and these studies are consistent with the presence of a dynamic helical structure whose sides are not completely hydrophilic or hydrophobic. This helical structure may occur in circulation when the peptide comes into contact with membranes. In this report, we discuss the current knowledge of the thymosin α1 structure and similar properties of thymosin β4 and thymosin β9, in different environments.[3]
Thymosin β4 sustained release from poly (lactide-co-glycolide) microspheres: synthesis and implications for treatment of myocardial ischemia
Following stroke or traumatic damage, neuronal death via both necrosis and apoptosis causes loss of functions, including memory, sensory perception, and motor skills. As necrosis has the nature to expand, while apoptosis stops the cell death cascade in the brain, necrosis is considered to be a promising target for rapid treatment for stroke. We identified the nuclear protein, prothymosin alpha (ProTα) from the conditioned medium of serum-free culture of cortical neurons as a key protein-inhibiting necrosis. In the culture of cortical neurons in the serum-free condition without any supplements, ProTα inhibited the necrosis, but caused apoptosis. In the ischemic brain or retina, ProTα showed a potent inhibition of both necrosis and apoptosis. By use of anti-brain-derived neurotrophic factor or anti-erythropoietin IgG, we found that ProTα inhibits necrosis, but causes apoptosis, which is in turn inhibited by ProTα-induced neurotrophins under the condition of ischemia. From the experiment using anti-ProTα IgG or antisense oligonucleotide for ProTα, it was revealed that ProTα has a pathophysiological role in protecting neurons in stroke.[12]
Acute myocardial infarction is still one of the leading causes of death in the industrial nations. Even after successful revascularization, myocardial ischemia results in a loss of cardiomyocytes and scar formation. Embryonic EPCs (eEPCs), retroinfused into the ischemic region of the pig heart, provided rapid paracrine benefit to acute and chronic ischemia in a PI-3K/Akt-dependent manner. In a model of acute myocardial ischemia, infarct size and loss of regional myocardial function decreased after eEPC application, unless cell pre-treatment with thymosin β4 shRNA was performed. Thymosin ß4 peptide retroinfusion mimicked the eEPC-derived improvement of infarct size and myocardial function. In chronic ischemia (rabbit model), eEPCs retroinfused into the ischemic hindlimb enhanced capillary density, collateral growth, and perfusion. Therapeutic neovascularization was absent when thymosin ß4 shRNA was introduced into eEPCs before application. In conclusion, eEPCs are capable of acute and chronic ischemia protection in a thymosin ß4 dependent manner.[15]
Published studies have described a number of physiological properties and cellular functions of thymosin β4 (Tβ4), the major G-actin-sequestering molecule in mammalian cells. Those activities include the promotion of cell migration, blood vessel formation, cell survival, stem cell differentiation, the modulation of cytokines, chemokines, and specific proteases, the upregulation of matrix molecules and gene expression, and the downregulation of a major nuclear transcription factor. Such properties have provided the scientific rationale for a number of ongoing and planned dermal, corneal, cardiac clinical trials evaluating the tissue protective, regenerative and repair potential of Tβ4, and direction for future clinical applications in the treatment of diseases of the central nervous system, lung inflammatory disease, and sepsis. A special emphasis is placed on the development of Tβ4 in the treatment of patients with ST elevation myocardial infarction in combination with percutaneous coronary intervention.[17]
The effect of thymosin treatment of venous ulcers
Venous ulcers are responsible for about 70% of the chronic ulcers of the lower limbs. Standard of care includes compression, dressings, debridement of devitalized tissue, and infection control. Thymosin beta 4 (Tβ4), a synthetic copy of the naturally occurring 43 amino-acid peptide, has been found to have wound healing and anti-inflammatory properties, and is thought to exert its therapeutic effect through promotion of keratinocyte and endothelial cell migration, increased collagen deposition, and stimulation of angiogenesis. To assess the safety, tolerability, and efficacy of topically administered Tβ4 in patients with venous stasis ulcers, a double-blind, placebo-controlled, dose-escalation study was conducted in eight European sites (five in Italy and three in Poland) that enrolled and randomized 73 patients. The safety profile of all doses of administered Tβ4 was deemed acceptable and comparable to placebo. Efficacy findings from this Phase 2 study suggest that a Tβ4 dose of 0.03% may have the potential to accelerate wound healing and that complete wound healing can be achieved within 3 months in about 25% of the patients, especially among those whose wounds are small to moderate in size or mild to moderate in severity.[18]
A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin β4 in healthy volunteers
Synthetic thymosin beta 4 (Tβ4) may have a potential use in promoting myocardial cell survival during acute myocardial infarction. Four cohorts, with 10 healthy subjects each, were given a single intravenous dose of placebo or synthetic Tβ4. Cohorts received ascending doses of either 42, 140, 420, or 1260 mg. Following safety review, subjects were given the same dose regimen daily for 14 days. Safety evaluations, incidence of Treatment-Emergent Adverse Events, and pharmacokinetic parameters were evaluated. Adverse events were infrequent, and mild or moderate in intensity. There were no dose limiting toxicities or serious adverse events. Pharmacokinetic profile for single dose showed a dose proportional response, and an increasing half-life with increasing dose. Synthetic Tβ4 given intravenously as a single dose or in multiple daily doses for 14 days over a dose range of 42–1260 mg was well tolerated with no evidence of dose limiting toxicity. Further development for use in cardiac ischemia should be considered.[19]
Safety and Efficacy of an Injectable Extracellular Matrix Hydrogel for Treating Myocardial Infarction
- Sonya B. Seif-Naraghi1,*,
- Jennifer M. Singelyn1,*,
- Michael A. Salvatore2,
- Kent G. Osborn1,
- Jean J. Wang1,
- Unatti Sampat1,
- Oi Ling Kwan1,
- G. Monet Strachan1,
- Jonathan Wong3,
- Pamela J. Schup-Magoffin1,
- Rebecca L. Braden1,
- Kendra Bartels1,
- Jessica A. DeQuach2,
- Mark Preul4,
- Adam M. Kinsey2,
- Anthony N. DeMaria1,
- Nabil Dib1 and
- Karen L. Christman1,†
+Author Affiliations
- 1University of California, San Diego, La Jolla, CA 92093, USA.
- 2Ventrix, Inc., San Diego, CA 92109, USA.
- 3Biologics Delivery Systems, Irwindale, CA 91706, USA.
- 4Barrow Neurological Institute, Phoenix, AZ 85013, USA.
+Author Notes
- ↵* These authors contributed equally to this work.
- ↵†To whom correspondence should be addressed. E-mail: christman@eng.ucsd.edu
ABSTRACT
New therapies are needed to prevent heart failure after myocardial infarction (MI). As experimental treatment strategies for MI approach translation, safety and efficacy must be established in relevant animal models that mimic the clinical situation. We have developed an injectable hydrogel derived from porcine myocardial extracellular matrix as a scaffold for cardiac repair after MI. We establish the safety and efficacy of this injectable biomaterial in large- and small-animal studies that simulate the clinical setting. Infarcted pigs were treated with percutaneous transendocardial injections of the myocardial matrix hydrogel 2 weeks after MI and evaluated after 3 months. Echocardiography indicated improvement in cardiac function, ventricular volumes, and global wall motion scores. Furthermore, a significantly larger zone of cardiac muscle was found at the endocardium in matrix-injected pigs compared to controls. In rats, we establish the safety of this biomaterial and explore the host response via direct injection into the left ventricular lumen and in an inflammation study, both of which support the biocompatibility of this material. Hemocompatibility studies with human blood indicate that exposure to the material at relevant concentrations does not affect clotting times or platelet activation. This work therefore provides a strong platform to move forward in clinical studies with this cardiac-specific biomaterial that can be delivered by catheter.
- Copyright © 2013, American Association for the Advancement of Science
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REFERENCES OF THYMOSIN IN CARDIOVASCULAR DISEASE
Thymosins in Health and Disease II: 3rd International Symposium on The Emerging Clinical Applications of Tymosin beta 4 in Cardiovascular Disease
Annals of the New York Academy of Sciences, October 2012 Volume 1270 Pages vii-ix, 1–121.
Allan L. Goldstein, Enrico Garaci, Editors, Thymosins in Cardiovascular Disease, November 2012, Wiley-Blackwell
http://onlinelibrary.wiley.com/doi/10.1111/nyas.2012.1270.issue-1/issuetoc
http://www.wiley.com/WileyCDA/WileyTitle/productCd-1573319104.html?cid=RSS_WILEY2_LIFEMED
1 Use of the cardioprotectants thymosin β4 and dexrazoxane during congenital heart surgery: proposal for a randomized, double-blind, clinical trial (pages 59–65) Daniel Stromberg, Tia Raymond, David Samuel, David Crockford, William Stigall, Steven Leonard, Eric Mendeloff and Andrew Gormley Article first published online: 10 OCT 2012 | DOI: 10.1111/j.1749-6632.2012.06710.x
2 Cardiac repair with thymosin β4 and cardiac reprogramming factors (pages 66–72) Deepak Srivastava, Masaki Ieda, Jidong Fu and Li Qian Article first published online: 10 OCT 2012 | DOI: 10.1111/j.1749-6632.2012.06696.x
3 NMR structural studies of thymosin α1 and β-thymosins (pages 73–78) David E. Volk, Cynthia W. Tuthill, Miguel-Angel Elizondo-Riojas and David G. Gorenstein Article first published online: 10 OCT 2012 | DOI: 10.1111/j.1749-6632.2012.06656.x
4 Thymosin β4 sustained release from poly(lactide-co-glycolide) microspheres: synthesis and implications for treatment of myocardial ischemia (pages 112–119) Jeffrey E. Thatcher, Tré Welch, Robert C. Eberhart, Zoltan A. Schelly and J. Michael DiMaio Article first published online: 10 OCT 2012 | DOI: 10.1111/j.1749-6632.2012.06681.x
5 Corrigendum for Ann. N.Y. Acad. Sci. 2012. 1254: 57–65 (page 121) Article first published online: 10 OCT 2012 | DOI: 10.1111/j.1749-6632.2012.06793.x This article corrects: A bird’s-eye view of cell therapy and tissue engineering for cardiac regeneration Vol. 1254, Issue 1, 57–65, Article first published online: 30 APR 2012
Thymosins in Health and Disease: 2nd International Symposium,
Annals of the New York Academy of Sciences, May 2010 Volume 1194 Pages ix–xi, 1–230
http://onlinelibrary.wiley.com/doi/10.1111/nyas.2010.1194.issue-1/issuetoc
6. Preface to Thymosins in Health and Disease (pages ix–xi) Enrico Garaci and Allan L. Goldstein Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05493.x
7. Thymosin β4 and cardiac repair (pages 87–96) Santwana Shrivastava, Deepak Srivastava, Eric N. Olson, J. Michael DiMaio and Ildiko Bock-Marquette Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05468.x
8. Thymosin β4 facilitates epicardial neovascularization of the injured adult heart (pages 97–104) Nicola Smart, Catherine A. Risebro, James E. Clark, Elisabeth Ehler, Lucile Miquerol, Alex Rossdeutsch, Michael S. Marber and Paul R. Riley Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05478.x
9. Thymosin β4 enhances repair by organizing connective tissue and preventing the appearance of myofibroblasts (pages 118–124) H. Paul Ehrlich and Sprague W. Hazard III Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05483.x
10. Thymosin β4: a key factor for protective effects of eEPCs in acute and chronic ischemia (pages 105–111) Rabea Hinkel, Ildiko Bock-Marquette, Antonis K. Hazopoulos and Christian Kupatt Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05489.x Corrected by: Corrigendum for Ann. N. Y. Acad. Sci. 1194: 105–111 Vol. 1205, Issue 1, 284, Article first published online: 14 SEP 2010
11. Thymosin β4: a candidate for treatment of stroke? (pages 112–117) Daniel C. Morris, Michael Chopp, Li Zhang and Zheng G. Zhang Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05469.x
12. Prothymosin α as robustness molecule against ischemic stress to brain and retina (pages 20–26) Hiroshi Ueda, Hayato Matsunaga, Hitoshi Uchida and Mutsumi Ueda Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05466.x
13. Thymosin β4 and cardiac repair (pages 87–96) Santwana Shrivastava, Deepak Srivastava, Eric N. Olson, J. Michael DiMaio and Ildiko Bock-Marquette Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05468.x
14. Thymosin β4 facilitates epicardial neovascularization of the injured adult heart (pages 97–104) Nicola Smart, Catherine A. Risebro, James E. Clark, Elisabeth Ehler, Lucile Miquerol, Alex Rossdeutsch, Michael S. Marber and Paul R. Riley Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05478.x
15. Thymosin β4: a key factor for protective effects of eEPCs in acute and chronic ischemia (pages 105–111) Rabea Hinkel, Ildiko Bock-Marquette, Antonis K. Hazopoulos and Christian Kupatt Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05489.x Corrected by: Corrigendum for Ann. N. Y. Acad. Sci. 1194: 105–111 Vol. 1205, Issue 1, 284, Article first published online: 14 SEP 2010
16. Thymosin β4: a candidate for treatment of stroke? (pages 112–117) Daniel C. Morris, Michael Chopp, Li Zhang and Zheng G. Zhang Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05469.x
17.Thymosin β4: structure, function, and biological properties supporting current and future clinical applications (pages 179–189) David Crockford, Nabila Turjman, Christian Allan and Janet Angel Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05492.x
18. The effect of thymosin treatment of venous ulcers (pages 207–212) G. Guarnera, A. DeRosa and R. Camerini, on behalf of 8 European sites Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05490.x
19. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin β4 in healthy volunteers (pages 223–229) Dennis Ruff, David Crockford, Gino Girardi and Yuxin Zhang Article first published online: 3 MAY 2010 | DOI: 10.1111/j.1749-6632.2010.05474.x
Other related articles on this Open Access Online Scientific Journal include the following:
Gene Therapy Into Healthy Heart Muscle: Reprogramming Scar Tissue In Damaged Hearts
Human Embryonic-Derived Cardiac Progenitor Cells for Myocardial Repair
Human embryonic pluripotent stem cells and healing post-myocardial infarction
Resident-cell-based Therapy in Human Ischaemic Heart Disease: Evolution in the PROMISE of Thymosin beta4 for Cardiac Repair
http://pharmaceuticalintelligence.com/2012/04/30/93/
Heart Renewal by pre-existing Cardiomyocytes: Source of New Heart Cell Growth Discovered
Absorb™ Bioresorbable Vascular Scaffold: An International Launch by Abbott Laboratories
Heart patients’ skin cells turned into healthy heart muscle cells
Telling NO to Cardiac Risk
http://pharmaceuticalintelligence.com/2012/12/10/telling-no-to-cardiac-risk/
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I actually consider this amazing blog , âSAME SCIENTIFIC IMPACT: Scientific Publishing –
Open Journals vs. Subscription-based « Pharmaceutical Intelligenceâ, very compelling plus the blog post ended up being a good read.
Many thanks,Annette
I actually consider this amazing blog , âSAME SCIENTIFIC IMPACT: Scientific Publishing –
Open Journals vs. Subscription-based « Pharmaceutical Intelligenceâ, very compelling plus the blog post ended up being a good read.
Many thanks,Annette
I actually consider this amazing blog , âSAME SCIENTIFIC IMPACT: Scientific Publishing –
Open Journals vs. Subscription-based « Pharmaceutical Intelligenceâ, very compelling plus the blog post ended up being a good read.
Many thanks,Annette
I actually consider this amazing blog , âSAME SCIENTIFIC IMPACT: Scientific Publishing –
Open Journals vs. Subscription-based « Pharmaceutical Intelligenceâ, very compelling plus the blog post ended up being a good read.
Many thanks,Annette