Amniotic stem cells for cellular cardiomyoplasty: promises and premises.

Cellular cardiomyoplasty is undergoing intensive investigation as a new form of therapy for severely damaged hearts. Among several cell types, mesenchymal stem cells (MSCs) have been proposed as a potential cell source. MSC can be found in adult tissues or in fetal tissues like the umbilical chord blood, amniotic membrane, or amniotic fluid (AF). AF-MSCs have properties intermediate between embryonic and adult MSC, which make them particularly attractive for cellular regeneration. It has been shown that MSC could differentiate in cardiomyocytes-like cells in vitro. In some animal models, it has also been shown that transplanted MSC could engraft and show some cardiomyocytes-like characteristics. Since MSC do not express HLA-DR and present in vitro and in vivo immunosuppressive properties, they can be envisioned to be used in allogenic cellular cardiomyoplasty. Based on these promises, MSC from adult donors are currently used in small safety and feasibility trials. No clinical trial using AF-MSC has been performed yet. Still, the exact role of true cell repopulation and in situ cardiomyocytes differentiation versus pure paracrine effect after cell transplantation is currently much debated. Cellular cardiomyoplasty is a fascinating new area of investigation in regenerative medicine. Although considerable knowledge has been gained over the last decade on the use of MSC as a potential stem cell (SC) source, many issues remain unsolved. Because of several limitations in animal models, clinical studies in highly selected patients balancing the risks and benefits are required. In that regard, MSCs obtained from the fetal AF are a potential new source of SCs that need to be further investigated for cellular cardiomyoplasty. (c) 2009 Wiley-Liss, Inc.