Therapeutic angiogenesis by transplantation of human embryonic stem cell-derived CD133+ endothelial progenitor cells for cardiac repair

Abstract

Objective: This study aim to enhance endothelial differentiation of human embryonic stem cells (hESCs) by transduction of an adenovirus (Ad) vector expressing hVEGF165 gene (Ad-hVEGF165 ). Purified hESC-derived CD133+ endothelial progenitors were transplanted into a rat myocardial infarct model to assess their ability to contribute to heart regeneration. Methods: Optimal transduction efficiency with high cell viability was achieved by exposing differentiating hESCs to viral particles at a ratio of 1:500 for 4 h on three consecutive days. Results: Reverse transcription-PCR analysis showed positive upregulation of VEGF, Ang-1, Flt-1, Tie-2, CD34, CD31, CD133 and Flk-1 gene expression in Ad-hVEGF165 -transduced cells. Additionally, flow cytometric analysis of CD133, a cell surface marker, revealed an approximately fivefold increase of CD133 marker expression in Ad-hVEGF165 -transduced cells compared with the nontransduced control. Within a rat myocardial infarct model, transplanted CD133+ endothelial progenitor cells survived and participated, both actively and passively, in the regeneration of the infarcted myocardium, as seen by an approximately threefold increase in mature blood vessel density (13.62 ± 1.56 vs 5.11 ± 1.23; p < 0.01), as well as significantly reduced infarct size (28% ± 8.2% vs 76% ± 5.6%; p < 0.01) in the transplanted group compared with the culture medium-injected control. There was significant improvement in heart function 6 weeks post-transplantation, as confirmed by regional blood-flow analysis (1.72 ± 0.612 ml/min/g vs 0.8 ± 0.256 ml/min/g; p < 0.05), as well as echocardiography assessment of left ventricular ejection fraction (60.855% ± 7.7% vs 38.22 ± 8.6%; p < 0.05) and fractional shortening (38.63% ± 9.3% vs 25.2% ± 7.11%; p < 0.05). Conclusion: hESC-derived CD133+ endothelial progenitor cells can be utilized to regenerate the infarcted heart.