Abstract 62: Pim-1 Engineering of Human 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. Aging can exhaust hCPC pool and pose a challenge to effectively regenerating the damaged myocardium. There is a dire need to reverse the senescent phenotype of these hCPCs isolated from elderly patients to target large segment of population suffering from heart failure.
Objective: Demonstrate that Pim-1 engineering of human cardiac progenitor cells (hCPCs) isolated from elderly patients with heart failure can increase the telomere lengths, telomerase activity, population doubling and reverse their senescent phenotype.
Methods and Results: hCPCs positive for the putative stem cell marker c-kit were isolated from heart biopsy samples from patients undergoing Left Ventricular Assist Device (LVAD) implantation. hCPCs isolated from patients aged 75-85 years (n=3) with heart failure demonstrate decreased population doubling time concomitant with decreased telomere lengths measured by in situ hybridization and telomerase activity measured by TRAP assay compared to patients aged 60-73 years (n=3). hCPCs were engineered to express Pim-1-GFP (hCPCeP), a fused GFP version of the kinase by using a lentivirus expression system. The cell cycling time measured by population doubling is increased after over expression of Pim-1 in hCPCs isolated from old patients. Pim-1 modification significantly increased telomere lengths and telomerase activity indicative of reversal of senescent characteristics of aged hCPCs.
Conclusion: Ex vivo gene delivery of Pim-1 enhances telomere length, telomerase activity and decreases population-doubling time. Modification of aged hCPCs from elderly patients 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.