Abstract 13483: Peptide Inhibition of PTEN Improves Metabolic Recovery and Outcomes in a Murine Cardiac Arrest Model
Introduction: Recent work shows that PTEN inhibition protects against cardiomyocyte contractile dysfunction and death following ischemia/reperfusion. To further determine whether PTEN inhibition improves metabolic recovery and survival in a mouse model of cardiac arrest, we have designed a TAT fused cell-permeable peptide (TAT-PTEN9c) based on the c-terminal PDZ binding motif of PTEN for rapid tissue delivery. We hypothesized that TAT-PTEN9c interferes with endogenous PTEN binding to cell membrane adaptors resulting in increased Akt activation, causing Akt-enhanced glucose utilization (with decreased diversion of glucose via the alternate polyol pathway to sorbitol) and improved survival.
Methods: Mouse cardiomyocytes were isolated from 1-3 day old mouse pups. Western blot was used to identify concentrations of TAT-PTEN9c that enhanced Akt phosphorylation in mouse cardiomyocytes exposed to oxidant stress. C57BL6 mice were then subjected to an established KCL-induced 8 min cardiac arrest protocol. 30 mice after CPR were randomly assigned to receive saline or TAT-PTEN9c. MAP, ETCO2, and ECG were recorded until 4 h after successful cardiopulmonary resuscitation (CPR). TAT-PTEN9c (7.8 mg/kg) was given intravenously (IV) after CPR (n=10). As a measure of impaired glucose utilization, sorbitol content in heart and brain was determined by a fluorescence assay of NADH formation using sorbitol dehydrogenase and NAD+.
Results: TAT-PTEN9c peptide enhanced Akt activation in neonatal mouse cardiomyoctes in a concentration-dependent manner. Survival was significantly increased in the TAT-PTEN9c treated group compared to saline controls at 2 h (14/15, 93% vs. 9/15, 60%, P < 0.05) and 4 h (10/15, 67% vs. 6/15, 40%, P < 0.05) after CPR. Treated mice had increased Akt phosphorylation within 30 min after CPR in heart and brain tissues with significantly decreased sorbitol content, suggesting improved metabolic recovery and glucose utilization.
Conclusion: TAT-PTEN9c can be used after CPR in a mouse SCA model to rapidly enhance Akt activation and decrease glucose shunting via the polyol pathway in critical organs, preventing early cardiovascular collapse and death. Further work exploring the role of tissue sorbitol in sudden cardiac arrest injury is needed.
Author Disclosures: X. Zhu: None. H. Wang: None. Y. Wang: None. J. Li: None. A.R. Leff: None. T.L. Vanden Hoek: None.
- © 2015 by American Heart Association, Inc.