(688) - Distribution Pattern of Viable Resident C-Kit Positive Cardiac Stem Cells in the Human Ischemic Heart as a Pool for Cardiac Regeneration

Abstract

The existence and the distribution of resident human cardiac stem cells (hCSC) in the adult myocardium and their regenerative capacity are not fully defined. The purpose of this study was to isolate and to identify hCSC in humans undergoing elective heart surgery. Additionally, the distributional pattern of these cells was analysed. Tissue samples from the free wall, the appendage of the right atrium (RA), left atrium (LA) and from the left ventricle (LV) where taken during cardiac surgery. Mononuclear cells (MNCs) were isolated and marked for the stem cell marker c-kit (CD 117) and hematopoietic lineage markers (CD3, CD11b, CD19 and CD45). Quantitative and qualitative cell characteristics were analyzed by FACS. For showing that these cells are located in the heart immunohistology was performed. hCSC, positive for c-kit and negative for hematopoietic lineage markers could be isolated from the RA, LA and LV (n=20, each). There is neither a significant quantitative difference of viable c-kitpos cells (RA 8.71±2.64% vs. LA 9.98±3.02% of MNCs, P=0.76) nor in the c-kitpos and lineageneg cells (RA 4.80±1.76% vs. LA 4.99±1.69% of isolated MNCs, P=0.939) between the atria. The number of viable c-kitpos cells was significantly higher in both atria in comparison to the left ventricle (both atria 9.28±1.9% vs. LV 1.07±0.29% of isolated MNCs, p=0.01). The distributional pattern of hCSC implies that the intact atria could serve as autologous heart-derived progenitor pool for cardiac regeneration. Routine FACS analysis is a good approach for characterising these cells in the human heart.