The effect of CD34 cell telomere length and hTERT expression on the outcome of autologous CD34 cell transplantation in patients with chronic heart failure.

Age-related telomere attrition in stem/progenitor cells may diminish their functional capacity and thereby impair the outcome of cell-based therapies. The aim of the present study was to investigate the effect of CD34 cell telomere length and hTERT expression on the clinical outcome of autologous CD34 cell transplantation. We studied 43 patients with cardiomyopathy. Their peripheral blood CD34 cells were mobilized with granulocyte colony-stimulating factor, enriched by immunoselection and delivered transendocardially. Relative telomere length and expression levels of hTERT were measured using a real-time PCR assay. Immunoselected CD34 cells had longer telomere length compared to leukocytes in leukapheresis products (p=0.001). In multivariate analysis, CD34 cell telomere length was not associated with the clinical outcome (b=3.306, p=0.540). While hTERT expression was undetectable in all leukapheresis products, 94.4% of the CD34 enriched cell products expressed hTERT. Higher CD34hTERT expression was associated with a better clinical outcome on univariate analysis (b=87.911, p=0.047). Our findings demonstrate that CD34 cell telomere length may not influence the clinical outcome in cardiomyopathy patients treated with autologous CD34 cell transplantation. Larger studies are needed to validate the impact of the CD34hTERT expression on the clinical outcome of autologous CD34 cell transplantation.