Abstract 19198: Adult Human Heart Contains Two Populations of C-kit-Oct-4+SSEA-4+ Very Small Embryonic-Like Stem Cells (Isl-1- and Isl-1+)

Abstract

Very small embryonic-like cells (VSELs) express pluripotent stem markers (Oct-4,Nanog, SSEA-4). and in adult mice may be expanded and differentiatiated into three germ layers. In humans VSELs were found in cord blood and peripheral blood (PB). AIM: Comparison of VSELs isolated from human myocardium with cardiac stem cells (CSC) and to measure the mobilization into PB after cardiac surgery. METHODS: 32 patients undergoing CABG were enrolled. Right atrial appendage (RAA), left ventricle (LV) were collected. PB samples were drawn before and immediately after surgery, 24 hrs and 5-7 days after weaning from cardiopulmonary bypass. Tissue samples (0.5-1.0 cm3) were cut, digested in collagenase, passed through 70um cell strainer, centrifugated, resuspended and stained with antibodies CD34 FITC/CD133 APC/SSEA-4PE/CD45 APC-Cy7. Analyses were carried out on Image Stream System which is a combination of FACS and immunofluorescent microscope. RESULTS: VSELs and CSC were identified in LAA. VSELs had markedly smaller diameter (4.7 ± 0.2µm vs. 7.7 ± 0.4µm), were c-kit negative, expressed markers of pluripotent cells (Oct-4, SSEA-4) and CD133. Two populations of VSELs - both Isl-1 negative and positive were identified. Subpopulation of Oct-4+SSEA-4+Isl+ VSELs contained cells of intermediate size (5.7 ± 0.7µm) and might form more mature population of VSELs progenitors. VSELs undergo significant mobilization into PB following the CABG. CONCLUSION: Human myocardium in adults contains two subpopulations of Oct-4+SSEA4+ VSELs which are distinct from CSC. Cardiac surgery with cardiopulmonary bypass induced mobilization of VSELs into peripheral blood.