Comparison of the Cardiomyogenic Potency of Human Amniotic Fluid and Bone Marrow Mesenchymal Stem Cells

BACKGROUND AND OBJECTIVES: Most studies in cardiac regeneration have explored bone marrow mesenchymal stem cells (BM-MSC) with variable therapeutic effects. Amniotic fluid MSC (AF-MSC) having extended self-renewal and multipotent properties may be superior to bone marrow MSC (BM-MSC). However, a comparison of their cardiomyogenic potency has not been studied yet. METHODS: The 5-azacytidine (5-aza) treated AF-MSC and BM-MSC were evaluated for the expression of GATA-4, Nkx2.5 and ISL-1 transcripts and proteins by quantitative RT-PCR and Western blotting, respectively as well as for the expression of cardiomyogenic differentiation markers cardiac troponin-T (cTNT), beta myosin heavy chain (βMHC) and alpha sarcomeric actinin (ASA) by immunocytochemistry. RESULTS: The AF-MSC as compared to BM-MSC had significantly higher expression of GATA-4 (183.06±29.85 vs. 9.80±0.05; p<0.01), Nkx2.5 (8.3±1.4 vs. 1.82±0.32; p<0.05), and ISL-1 (39.59±4.05 vs. 4.36±0.39; p<0.01) genes as well as GATA-4 (2.01±0.5 vs. 0.6±0.1; p<0.05), NKx2.5 (1.9±0.14 vs. 0.8±0.2; p<0.01) and ISL-1 (1.7±0.3 vs. 0.9±0.1; p<0.05) proteins. The AF-MSC also had significantly elevated expression of cTNT (5.0×10(4)±0.6×10(4) vs. 3.5 ×10(4)±0.8×10(4); p<0.01), β-MHC (15.7×10(4)±0.9×10(4) vs. 8.2×10(4)±0.6×10(4); p<0.01) and ASA (18.6×10(4)±4.9×10(4) vs. 13.1×10(4)±3.0×10(4); p<0.05) than BM-MSC. CONCLUSIONS: Our data suggest that AF-MSC have greater cardiomyogenic potency than BM-MSC, and thus may be a better source of MSC for therapeutic applications in cardiac regenerative medicine.