PPARγ Agonist Pioglitazone Prevents Hypoxia-induced Cardiac Dysfunction by Reprogramming Glucose Metabolism

TL;DR

Pioglitazone prevents heart problems caused by low oxygen at high altitudes by changing how the heart uses glucose for energy.

Contribution

Pioglitazone prevents hypoxia-induced cardiac dysfunction by reprogramming glucose metabolism, independent of insulin sensitivity.

Findings

Pioglitazone improves heart function in hypoxic mice by enhancing glucose metabolism.

Pioglitazone reduces mitochondrial ROS production and maintains ATP production in cardiomyocytes under hypoxia.

HIF-1α inhibition disrupts pioglitazone's protective effects on cardiac metabolism and function.

Abstract

The heart relies on various defense mechanisms, including metabolic plasticity, to maintain its normal structure and function under high-altitude hypoxia. Pioglitazone, a peroxisome proliferator-activated receptor γ (PPARγ), sensitizes insulin, which in turn regulates blood glucose levels. However, its preventive effects against hypoxia-induced cardiac dysfunction at high altitudes have not been reported. In this study, pioglitazone effectively prevented cardiac dysfunction in hypoxic mice for 4 weeks, independent of its effects on insulin sensitivity. In vitro experiments demonstrated that pioglitazone enhanced the contractility of primary cardiomyocytes and reduced the risk of QT interval prolongation under hypoxic conditions. Additionally, pioglitazone promoted cardiac glucose metabolic reprogramming by increasing glycolytic capacity; enhancing glucose oxidation, electron transfer, and oxidative phosphorylation processes; and reducing mitochondrial reactive ROS production, which ultimately maintained mitochondrial membrane potential and ATP production in cardiomyocytes under hypoxic conditions. Notably, as a PPARγ agonist, pioglitazone promoted hypoxia-inducible factor 1α (HIF-1α) expression in hypoxic myocardium. Moreover, KC7F2, a HIF-1α inhibitor, disrupted the reprogramming of cardiac glucose metabolism and reduced cardiac function in pioglitazone-treated mice under hypoxic conditions. In conclusion, pioglitazone effectively prevented high-altitude hypoxia-induced cardiac dysfunction by reprogramming cardiac glucose metabolism.

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