thymosin and Heart-Diseases

Treatment with thymosin beta 4 (Tβ4) reduces infarct volume and preserves cardiac function in preclinical models of cardiac ischemic injury. These effects stem in part from decreased infarct size, but additional benefits are likely due to specific antifibrotic and proangiogenic activities. Injected or transgenic Tβ4 increase blood vessel growth in large and small animal models, consistent with Tβ4 converting hibernating myocardium to an actively contractile state following ischemia. Tβ4 and its degradation products have antifibrotic effects in in vitro assays and in animal models of fibrosis not related to cardiac injury. This large number of pleiotropic effects results from Tβ4's many interactions with cellular signaling pathways, particularly indirect regulation of cellular motility and movement via the SRF-MRTF-G-actin transcriptional pathway. Variation in effects and effect sizes in animal models may potentially be due to variable distribution of Tβ4. Preclinical studies of PK/PD relationships and a reliable pharmacodynamic biomarker would facilitate clinical development of Tβ4.

Topics: Actins; Animals; Cardiotonic Agents; Disease Models, Animal; Heart Diseases; Humans; Myocardial Infarction; Myocardium; Signal Transduction; Thymosin

Clinical interventions leading to improved survival in patients with acute myocardial infarction have, paradoxically, increased the need for cardiac regenerative strategies as more people are living with heart failure. Over the last 10-15 years there have been significant advances in our understanding of cell-based therapy for cardiac repair. Evidence that paracrine stimulation largely underlies the functional benefits in cell transplantation has led to a paradigm shift in regenerative medicine: from cell therapy to factor/protein-based therapy. Although, future regenerative approaches may likely involve a synergistic protein cocktail, this review will focus on the role of a promising candidate, thymosin beta 4 (Tβ4) in cardioprotection, neovascularization, tissue regeneration and inflammation - all essential components in cardiac repair.

Topics: Gene Expression Regulation; Heart Diseases; Humans; Myocytes, Cardiac; Thymosin

Hypoxic heart disease is a predominant cause of disability and death worldwide. As adult mammals are incapable of cardiac repair after infarction, the discovery of effective methods to achieve myocardial and vascular regeneration is crucial. Efforts to use stem cells to repopulate damaged tissue are currently limited by technical considerations and restricted cell potential. We discovered that the small, secreted peptide thymosin beta4 (Tbeta4) could be sufficiently used to inhibit myocardial cell death, stimulate vessel growth, and activate endogenous cardiac progenitors by reminding the adult heart on its embryonic program in vivo. The initiation of epicardial thickening accompanied by increase of myocardial and epicardial progenitors with or without infarction indicate that the reactivation process is independent of injury. Our results demonstrate Tbeta4 to be the first known molecule able to initiate simultaneous myocardial and vascular regeneration after systemic administration in vivo. Given our findings, the utility of Tbeta4 to heal cardiac injury may hold promise and warrant further investigation.

Topics: Adult; Animals; Heart; Heart Diseases; Humans; Mice; Myocardium; Myocytes, Cardiac; Regeneration; Stem Cells; Thymosin; Wound Healing

Topics: Adaptor Proteins, Signal Transducing; Animals; Cell Movement; Cell Survival; DNA-Binding Proteins; Heart; Heart Diseases; LIM Domain Proteins; Membrane Proteins; Mice; Myocardium; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Regeneration; Regenerative Medicine; Thymosin; Wound Healing