Isolation, characterization and differentiation potential of cardiac progenitor cells in adult pigs

In vitro differentiation of progenitor cells isolated from juvenile pig hearts - expression of relevant gene and protein markers

OBJECTIVES

Heart failure is a significant cause of mortality worldwide, and most current therapies treat only its symptoms. The results of cardiac stem cell research suggest a promising treatment option for heart failure, but there is currently an unmet demand for better research models. We have therefore, for the first time, isolated, expanded and differentiated progenitor cells obtained from juvenile pig hearts to use as a platform for cardiac stem cell research.

DESIGN

Progenitor cells were isolated from the left ventricles of porcine hearts using collagenase enzymatic digestion and Percoll^®-gradient centrifugation. Cells were proliferated in Matrigel^®-coated wells. Cell differentiation was initiated by applying 5-azacytidine and subsequently controlled by modifying the serum concentration. Western blotting and qPCR were used to determine protein and gene expression, respectively.

RESULTS

Cardiac-specific genes, from the following proteins: troponin I-3, and myosin-heavy-chain 7 were stably expressed during proliferation and differentiation. Connexin-43 was upregulated and Actinin alfa 2 was downregulated during differentiation. The immature-cardiomyocyte marker GATA binding protein 4 was stably expressed but with a decrease in expression at day 4 of differentiation. Smooth muscle actin decreased in expression and Von Willebrand factor were stably expressed during differentiation. Smooth muscle protein expression was documented but no expression of cardiac-specific proteins after differentiation was found.

CONCLUSION

The isolated progenitor cells had key cardiac-lineage gene expression characteristics but they did not express cardiac-specific proteins. Smooth muscle protein was expressed confirming commitment to the smooth muscle lineage.

Heart Regeneration with Embryonic Cardiac Progenitor Cells and Cardiac Tissue Engineering

Myocardial infarction (MI) is the leading cause of death worldwide. Recent advances in stem cell research hold great potential for heart tissue regeneration through stem cell-based therapy. While multiple cell types have been transplanted into MI heart in preclinical studies or clinical trials, reduction of scar tissue and restoration of cardiac function have been modest. Several challenges hamper the development and application of stem cell-based therapy for heart regeneration. Application of cardiac progenitor cells (CPCs) and cardiac tissue engineering for cell therapy has shown great promise to repair damaged heart tissue. This review presents an overview of the current applications of embryonic CPCs and the development of cardiac tissue engineering in regeneration of functional cardiac tissue and reduction of side effects for heart regeneration. We aim to highlight the benefits of the cell therapy by application of CPCs and cardiac tissue engineering during heart regeneration.

The potential of stem cells in the treatment of cardiovascular diseases

Although the adult mammalian heart was once believed to be a post-mitotic organ without any capacity for regeneration, recent findings have challenged this dogma. A modified view assigns to the mammalian heart a measurable capacity for regeneration throughout life. The ultimate goals of the cardiac regeneration field have been pursued by multiple strategies, including understanding the developmental biology of cardiomyocytes and cardiac stem and progenitor cells, applying chemical genetics, and engineering biomaterials and delivery methods that facilitate cell transplantation. Successful stimulation of endogenous regenerative capacity in injured adult mammalian hearts can benefit from studies of natural cardiac regeneration.