Transplantation of Immortalized CD34+ and CD34- Adipose-Derived Stem Cells Improve Cardiac Function and Mitigate Systemic Pro-Inflammatory Responses

Adipose-derived stem cells (ADSCs) have the potential to differentiate into various cell lineages and they are easily obtainable from patients, which makes them a promising candidate for cell therapy. However, a drawback is their limited life span during in vitro culture. Therefore, hTERT-immortalized CD34+ and CD34- mouse ADSC lines (mADSCs(hTERT)) tagged with GFP were established. We evaluated the proliferation capacity, multi-differentiation potential, and secretory profiles of CD34+ and CD34- mADSCs(hTERT) in vitro, as well as their effects on cardiac function and systemic inflammation following transplantation into a rat model of acute myocardial infarction (AMI) to assess whether these cells could be used as a novel cell source for regeneration therapy in the cardiovascular field. CD34+ and CD34- mADSCs(hTERT) demonstrated phenotypic characteristics and multi-differentiation potentials similar to those of primary mADSCs. CD34+ mADSCs(hTERT) exhibited a higher proliferation ability compared to CD34- mADSCs(hTERT), whereas CD34- mADSCs(hTERT) showed a higher osteogenic differentiation potential compared to CD34+ mADSCs(hTERT). Primary mADSCs, CD34+, and CD34- mADSCs(hTERT) primarily secreted EGF, TGF-β1, IGF-1, IGF-2, MCP-1, and HGFR. CD34+ mADSCs(hTERT) had higher secretion of VEGF and SDF-1 compared to CD34- mADSCs(hTERT). IL-6 secretion was severely reduced in both CD34+ and CD34- mADSCs(hTERT) compared to primary mADSCs. Transplantation of CD34+ and CD34- mADSCs(hTERT) significantly improved the left ventricular ejection fraction and reduced infarct size compared to AMI-induced rats after 28 days. At 28 days after transplantation, engraftment of CD34+ and CD34- mADSCs(hTERT) was confirmed by positive Y chromosome staining, and differentiation of CD34+ and CD34- mADSCs(hTERT) into endothelial cells was found in the infarcted myocardium. Significant decreases were observed in circulating IL-6 levels in CD34+ and CD34- mADSCs(hTERT) groups compared to the AMI-induced control group. Transplantation of CD34- mADSCs(hTERT) significantly reduced circulating MCP-1 levels compared to the AMI control and CD34+ mADSCs(hTERT) groups. GFP-tagged CD34+ and CD34- mADSCs(hTERT) are valuable resources for cell differentiation studies in vitro as well as for regeneration therapy in vivo.