The Current State of Stem Cell Therapeutics: Canadian Approaches in the International Context

After ischemic injury, the endogenous repair mechanisms of the human heart are insufficient for meaningful tissue regeneration, so muscle lost is replaced by noncontractile scar tissue. Current treatments for ischemic cardiomyopathy improve quality of life and increase life expectancy, but cannot cure the underlying disease of cardiomyocyte loss. Cellular transplantation is emerging as a valuable therapeutic approach to heal the ischemic heart. Adult bone marrow stem cells are capable of differentiation, regeneration of infarcted myocardium, and induction of myogenesis and angiogenesis, ultimately leading to improved contractility. Positive results from animal studies have prompted several clinical trials to ascertain the safety and feasibility of cell therapy. However, despite all the excitement in stem cell research resulting from initial experimental data and preliminary clinical trials, the mixed results observed have raised many unanswered questions. A major obstacle to the identification of the optimal cell therapy is that the fate of the implanted cells and the nature of their beneficial effects are ill-defined. A better understanding is fundamental for the development of new therapeutic agents, and to optimize stem cell applications. Well-designed and powered double-blinded randomized studies are clearly needed to confirm promising findings from early studies. With several ongoing randomized trials directed toward evaluation of stem cell therapies in patients with acute or chronic ischemic cardiomyopathy, the Canadian initiative represents a milestone.

RésuméAprès l’accident ischémique, les mécanismes de réparation endogène du cœur humain ne permettent pas une régénération tissulaire satisfaisante. Par conséquent, la perte de tissu musculaire est remplacée par du tissu cicatriciel non contractile. Les traitements actuels de la cardiomyopathie ischémique améliorent la qualité de vie et augmentent l’espérance de vie, mais ne peuvent pas guérir la maladie sous-jacente liée à la perte des cardiomyocytes. La greffe de cellules apparaît comme une approche thérapeutique valable pour favoriser la guérison du cœur ayant subi une ischémie. Les cellules souches de moelle osseuse sont capables de se différencier, de régénérer le myocarde infarci et d’induir