Benefit of stem cells and skeletal myoblast cells in dilated cardiomyopathies

Remodeled eX vivo muscle engineered tissue improves heart function after chronic myocardial ischemia

The adult heart displays poor reparative capacities after injury. Cell transplantation and tissue engineering approaches have emerged as possible therapeutic options. Several stem cell populations have been largely used to treat the infarcted myocardium. Nevertheless, transplanted cells displayed limited ability to establish functional connections with the host cardiomyocytes. In this study, we provide a new experimental tool, named 3D eX vivo muscle engineered tissue (X-MET), to define the contribution of mechanical stimuli in triggering functional remodeling and to rescue cardiac ischemia. We revealed that mechanical stimuli trigger a functional remodeling of the 3D skeletal muscle system toward a cardiac muscle-like structure. This was supported by molecular and functional analyses, demonstrating that remodeled X-MET expresses relevant markers of functional cardiomyocytes, compared to unstimulated and to 2D- skeletal muscle culture system. Interestingly, transplanted remodeled X-MET preserved heart function in a murine model of chronic myocardial ischemia and increased survival of transplanted injured mice. X-MET implantation resulted in repression of pro-inflammatory cytokines, induction of anti-inflammatory cytokines, and reduction in collagen deposition. Altogether, our findings indicate that biomechanical stimulation induced a cardiac functional remodeling of X-MET, which showed promising seminal results as a therapeutic product for the development of novel strategies for regenerative medicine.

Stem cell therapy for heart failure

"During the past decade, studies in animals and humans have suggested that cell therapy has positive effects for the treatment of heart failure. This clinical effect may be mediated by angiogenesis and reduction in fibrosis rather than by regeneration of myocytes. Increased microvasculature and decreased scar also likely lead to improved cardiac function in the failing heart. The effects of cell therapy are not limited to one type of cell or delivery technique. Well-designed, large-scale, randomized clinical trials with objective end points will help to fully realize the therapeutic potential of cell-based therapy for treating heart failure."

Myoblasts and embryonic stem cells differentially engraft in a mouse model of genetic dilated cardiomyopathy

The functional and architectural benefits of embryonic stem cells (ESC) and myoblasts (Mb) transplantations into infarcted myocardium have been investigated extensively. Whereas ESC repopulated fibrotic areas and contributed to myocardial regeneration, Mb exerted their effects through paracrine secretions and scar remodeling. This therapeutic perspective, however, has been less explored in the setting of nonischemic dilated cardiomyopathies (DCMs). Our aim was to compare the integration and functional efficacy of ESC committed to cardiac fate by bone morphogenic protein 2 (BMP-2) pretreatment and Mb used as gold standard following their transplantation into the myocardium of a mouse model of laminopathy exhibiting a progressive and lethal DCM. After 4 and 8 weeks of transplantation, stabilization was observed in Mb-transplanted mice (P = 0.008) but not in groups of ESC-transplanted or medium-injected animals, where the left ventricular fractional shortening (LVFS) decreased by 32 ± 8% and 41 ± 8% respectively. Engrafted differentiated cells were consistently detected in myocardia of mice receiving Mb, whereas few or no cells were detected in the hearts of mice receiving ESC, except in two cases where teratomas were formed. These data suggest that committed ESC fail to integrate in DCM where scar tissue is absent to provide the appropriate niche, whereas the functional benefits of Mb transplantation might extend to nonischemic cardiomyopathy.