Abstract 1075: Chemokine Preconditioning of Bone Marrow Mesenchymal Stem Cells Enhances their Proliferation and Prevents Apoptosis
Background: Apoptosis contributes to cardiac cell death after ischemia. We hypothesized that chemokine preconditioning (PC) enhances cell survival, proliferation and engraftment of mesenchymal stem cells (MSCs) by reducing apoptosis.
Methods: MSCs were grouped (n=6) without PC (group1), PC with chemokine, SDF-1 (0.05μg/ml ;group 2), with CXCR4 antagonist, AMD 3100(5μg/ml; group3), and with SDF-1, AMD3100 (0.05μg/ml, 5μg/ml;group4) respectively. MSCs in various groups were treated with H2 O2 (100 μmol/l) for 60minutes. LDH release and trypan blue exclusion assay were used as markers for cell injury and cell viability. Cell proliferative activity was determined by cell proliferation assay and apoptosis by annexin-v staining. PC cells were labeled with PKH26 before transplantation. Rats were grouped (n = 6) after LAD ligation in rats for 4 weeks to receive the intramyocardial injection of 20μl DMEM without cells, or with 5 × 105 MSCs without PC(group1) ,or with SDF-1 PC (group2), AMD3100 PC(group3) and with SDF-1, AMD 3100 PC(group4 ).Echocardiography was performed at four weeks and hearts were harvested and analyzed for CD31 and c-Kit positive cells and fibrosis.
Results: In vitro data showed marked increase in cell viability and proliferative activity while significant decrease in LDH release and annexin-v positive cells were observed in SDF-1 PC group 2 vs group1 (P< 0.05).In vivo data showed that ejection fraction was significantly improved, with increase in the c-Kit and CD31 positive cells in infarcted and peri infarcted areas while fibrosis was substantially reduced in group 2(Table⇓)
Conclusion: We conclude that PC suppresses MSCs apoptosis and enhances their survival and improves myocardial function. The data further show that PC may prove a novel approach in cell based therapeutics.