Abstract 13587: Pim-1 Engineering oHuman CPCs Increases Telomere Length from Aged Patients with Heart Failure
Rationale: Adoptive transfer of human cardiac progenitor cells (hCPCs) can repair damaged myocardium and improve function in a pathologically challenged heart. Progression of disease and / or advancing age exhaust the hCPC pool, thereby compromising effective regeneration of damaged or aged myocardium. There is a dire need to reverse the senescent phenotype of hCPCs isolated from patients to improve the outcome of regenerative therapy for a large segment of the population suffering from heart failure.
Objective: Demonstrate that Pim-1 engineering reverses the senescent phenotype of human cardiac progenitor cells (hCPCs) isolated from patients with heart failure increases telomere length, telomerase activity, and decreases population doubling.
Methods and Results: hCPCs positive for stem cell marker c-kit were isolated from heart biopsy samples from patients undergoing Left Ventricular Assist Device (LVAD) implantation. hCPCs with slow growth kinetics exhibit decreased telomere length measured by in situ hybridization and telomerase activity measured by TRAP assay concomitant with increased population doubling time compared to hCPCs with fast growth kinetics. hCPCs with slow growth kinetics were engineered to express Pim-1-GFP (hCPCeP), a fused GFP version of the kinase by using a lentivirus expression system. Cell cycling measured by population doubling time was decreased in hCPCeP relative to control hCPC engineered with GFP alone (hCPCe). Telomere lengths and telomerase activity in hCPCeP were significantly increased in hCPCeP relative to hCPCe indicative of reversal of senescent characteristics.
Conclusion: Ex vivo gene delivery of Pim-1 enhances telomere length, telomerase activity and decreases population-doubling time. Modification of hCPCs with slow growth kinetics from patients with heart failure can augments their ability to regenerate damaged myocardium, making stem cell engineering a viable option to address current limitations associated with senescent phenotype of aged hCPCs.
- © 2012 by American Heart Association, Inc.