The dying stem cell hypothesis proposes that apoptosis of transplanted stem cells after myocardial infarction modulates local immune reactions, leading to reduced scar formation and improved outcomes.
Does stem cell transplantation improve cardiac outcome after myocardial infarction via apoptosis of transplanted cells?
The 'dying stem cell hypothesis' proposes that the therapeutic benefits of stem cell transplantation after myocardial infarction arise from the immunomodulatory effects of apoptotic donor cells rather than their direct engraftment.
Stem cell transplantation after myocardial infarction has been claimed to restore cardiac function, but the underlying mechanism remains unclear. A minority of transplanted cells become adherent in heart tissue and contribute to neovascularization, whereas many donor cells die from apoptosis. We propose that apoptosis of transplanted cells modulates local tissue reactions. Apoptotic cells impact on immune reactivity by down-regulating innate and adaptive immunity, deactivating macrophages and dendritic cells, and stimulating regulatory T cells. This leads to reduced scar formation, repressed myocardial apoptosis, and improved cardiac outcome.
Thum et al. (2005) conducted a review in Myocardial infarction. Stem cell transplantation was evaluated. The dying stem cell hypothesis proposes that apoptosis of transplanted stem cells after myocardial infarction modulates local immune reactions, leading to reduced scar formation and improved outcomes.