Abstract 168: Intermittent Hypoxic/Hyperoxic Cycling Improves Survival of Human Inducible Pluripotent-Derived Cardiomyocytes Subjected to Prolonged Hypoxia
Background: Ischemic and hypoxic pre-conditioning has demonstrated a robust early and late cardioprotection in the heart. Hypoxic pre-conditioning has recently been used with some success to prolong stem cell survival prior to transplantation in the heart. In our previous work, we have noted hyperoxia exposure may also provide a pre-conditioning stimulus.
Hypothesis: We hypothesized that brief periods of hypoxic/hyperoxic cycling of human inducible pluripotent derived cardiomyocytes (hiPSC-CMs) prior to prolonged hypoxic exposure will improve cardiomyocyte survival.
Methods: Three groups of hiPSC-CMs were studied; 1) HYP group (hypoxia, 0% O2 for 20 hours), 2) HP21 group (two alternate cycles of hypoxia, 0% O2 /normoxia, 21% O2 + 20 hours hypoxia), 3) HP95 group (two alternate cycles of hypoxia, 0% O2/hyperoxia, 95% O2 + 20 hours hypoxia). After the prolonged hypoxic exposure, all three groups were immediately imaged for cell viability using live cell DAPI and phase contrast microscopy. Dihydroethidine (DHE) staining was performed to measure superoxide levels in cells via confocal imaging. eNOS and MAPK signaling proteins were measured by western blot analysis.
Results: Fluorescence and phase contrast imaging showed increased survival of hiPSC-CMs in the HP95 group, when compared to HP21 or HYP groups. Increased levels (2-3 fold) of eNOS and MAPK protein signaling were observed in the HP95 group along with decreased superoxide levels, when compared to HP21 and HYP groups.
Conclusions: This study demonstrates for the first time that hypoxic/hyperoxic cycling improves cell survival and decreases superoxide production in hiPSC-CMs through a nitric oxide mediated pathway. This strategy of hyperoxic cycling may be applied to hiPSC-CMs prior to in-vivo transplantation to improve the survival of transplanted cells in the ischemic heart.
Author Disclosures: M. Khan: None. A. Basye: None. C. Chen: None. M. Angelos: None.
- © 2014 by American Heart Association, Inc.