Abstract 243: The Role of Reactive Oxygen Species in Hyperglycemia-Induced Attenuation of Anesthetic Preconditioning in Induced Pluripotent Stem Cell-Derived Cardiomyocytes
Anesthetic Preconditioning (APC) protects the myocardium from ischemia/reperfusion injury. The cardioprotective effects of APC is diminished or even eliminated in individuals with diabetes mellitus and/or hyperglycemia. The development of patient-specific induced pluripotent stem cells and their differentiation capability has provided us with an in vitro model to study the inefficiency of APC in these individuals.To investigate the underlying mechanisms involved in the attenuation of APC in both diabetic individuals and in hyperglycemia we utilized cardiomyocytes derived from Type 2 diabetic patient and healthy individual iPSCs, (T2DM-iPSCs and N-iPSCs, respectively).
Contracting cardiomyocytes were dissociated and selected by the expression of green fluorescent protein under the transcriptional control of myosin light chain-2v. Cardiomyocytes were exposed to varying glucose concentrations (5, 11, and 25 mM). Lactate dehydrogenase (LDH) release was measured using a colorimetric cytotoxicity assay kit and read spectrophotometrically. Mitochondrial membrane potential and reactive oxygen species (ROS) generation were measured with confocal microscopy.
APC reduced oxidative stress-induced lactate dehydrogenase (LDH) release in cardiomyocytes derived from both N-iPSCs- and T2DM-iPSCs in 5 and 11 mM glucose concentrations, but not in 25 mM glucose. Baseline membrane potential was similar between non-diabetic- and Type 2 diabetic-derived cardiomyocytes; however 25 mM glucose hyperpolarized the mitochondrial membrane potential. T2DM-iPSC-derived cardiomyocytes had an increase in ROS baseline levels compared to N-iPSC-derived cardiomyocytes. Additionally, high glucose concentrations increased oxidative stress-induced ROS production compared to lower glucose conditions in both cell lines.
Our preliminary data shows that high glucose generates excessive ROS and hyperpolarizes the mitochondrial membrane and may contribute to the inefficiency of diabetic and/or hyperglycemic individuals to be anesthetically preconditioned. By utilizing human iPSC-derived cardiomyocytes we can begin to understand the inability of hyperglycemic and diabetic individuals to be anesthetically preconditioned.
- © 2012 by American Heart Association, Inc.