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 multi-potent 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 (eTNT), beta myosin heavy chain (beta MHC) 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 9 +/- 0.1; p<0.05) proteins. The AF-MSC also had significantly elevated expression of cTNT (5.0 x 10(4)+/- 0.6 x 10(4) vs. 3.5 x 10(4)+/- 0.8 x 10(4); p<0.01), beta-MHC (15.7 x 10(4)+/- 0.9 x 10(4) vs. 8.2 x 10(4)+/- 0.6 x 10(4); p<0.01) and ASA (18.6 x 10(4)+/- 4.9 x 10(4 )vs 13.1 x 10(4) +/- 3.0 x 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.