High Glucose Attenuates Anesthetic Cardioprotection in Stem-Cell–Derived Cardiomyocytes: The Role of Reactive Oxygen Species and Mitochondrial Fission

Abstract

BACKGROUND Hyperglycemia can blunt the cardioprotective effects of isoflurane in the setting of ischemia-reperfusion injury. Previous studies suggest that reactive oxygen species (ROS) and increased mitochondrial fission play a role in cardiomyocyte death during ischemia-reperfusion injury. To investigate, the role of glucose concentration in ROS production and mitochondrial fission during ischemia-reperfusion (with and without anesthetic protection), we used the novel platform of human-induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CMs). METHODS Cardiomyocyte differentiation from iPSC was characterized by the expression of CM-specific markers using immunohistochemistry and by measuring contractility. iPSC-CMs were exposed to varying glucose conditions (5, 11, 25 mM) for 24 hours. Mitochondrial permeability transition pore (mPTP) opening, cell viability, and ROS generation end-points were used to assess the effects of various treatment conditions. Mitochondrial fission was monitored by the visualization of fragmented mitochondria using confocal microscopy. Expression of activated dynamin-related protein 1 (Drp1), a key protein responsible for mictochodrial fission was assessed by western blot. RESULTS Cardiomyocytes were successfully differentiated from iPSC. Elevated glucose conditions (11 and 25 mM) significantly increased ROS generation, while only the 25 mM high glucose condition induced mitochondrial fission and increased the expression of activated Drp1 in iPSC-CMs. Isoflurane delayed mPTP opening and protected iPSC-CMs from oxidative stress in 5 and 11 mM glucose conditions to a similar level as previously observed in various isolated animal cardiomyocytes. Scavenging ROS with Trolox or inhibiting mitochondrial fission with mdivi-1 restored the anesthetic cardioprotective effects in iPSC-CMs in 25 mM glucose conditions. CONCLUSIONS Human iPSC-CM is a useful, relevant model for studying isoflurane cardioprotection, and can be manipulated to recapitulate complex clinical perturbations. We demonstrate that the cardioprotective effects of isoflurane in elevated glucose conditions can be restored by scavenging ROS or inhibiting mitochondrial fission. These findings may contribute to further understanding and guidance for restoring pharmacological cardioprotection in hyperglycemic patients.

Tongxinluo attenuates reperfusion injury in diabetic hearts by angiopoietin-like 4-mediated protection of endothelial barrier integrity via PPAR-α pathway

“…This is because that diabetes mellitus increases myocardial susceptibility to I/R injury [ 22 ]. During diabetes mellitus, O-linked-N-acetylglucosamine (O-GlcNAc) modification of acetaldehyde dehydrogenase 2 (ALDH2), an important cardioprotective enzyme [ 23 ], is enhanced, interleukin (IL)-33 is downregulated [ 19 ], PKC-βII [ 19 ] and xanthine oxidase [ 22 ] are activated, thioredoxin-1 is nitratively inactivated [ 21 ], thioredoxin-interacting protein (Txnip) [ 20 ] and NADPH oxidase [ 22 ] are upregulated, nitric oxide synthase is uncoupled [ 22 ], and antioxidant capacities is impaired [ 22 ], resulting in exaggeration of oxidative stress, inflammation, mitochondrial fission [ 24 ] and apoptosis, and subsequently amplification of myocardial I/R injury [ 19 – 24 ].…”

Cytotoxicity of propofol in human induced pluripotent stem cell-derived cardiomyocytes

“…A study reported that genes associated with mitochondrial energy metabolism in iPSC-derived cardiomyocytes showed lower expression levels than native cardiac tissue; nevertheless, these cells had potential as a screening model for drug-induced mitochondrial toxicity [ 19 ]. iPSC-derived cardiomyocytes were used to study the cardioprotective effects of isoflurane under oxidative stress conditions by evaluating mitochondrial morphology and function [ 20 , 21 ]. In this context, iPSC-derived cardiomyocytes could be used for evaluation of mitochondrial function.…”

Mitochondrial Dynamics: Biogenesis, Fission, Fusion, and Mitophagy in the Regulation of Stem Cell Behaviors

“…In periodontal ligament stem cells, CoCl 2 treatment, a condition mimicking hypoxia (pseudohypoxia), results in ROS-mediated mito-fission and apoptosis, which can be rescued by NAC [67]. Energy overloading can also induce oxidative stress and promote mito-fission [20, 69]. Prolonged exposure to saturated free fatty acids (e.g., palmitate) is cytotoxic to neural stem cells, which can be prevented by the Drp1 inhibitor mDivi-1 [41].…”