Python cardiomyocytes store lipids to buffer against hyperlipidemia

Abstract

Burmese pythons (Python bivittatus) eat large meals infrequently and experience a transient but robust increase in cardiac mass and metabolic rate during digestion. Accompanying these changes is a surge in circulating triglycerides. In mammals, overconsumption of food is associated with obesity and lipotoxicity, which increase the risk of heart disease and metabolic syndrome. The invasive and thriving population of pythons in the Florida Everglades eat continuously, suggesting they experience sustained high circulating triglyceride and cholesterol levels. In this study, we designed a chronic frequent feeding regimen to investigate whether python hearts are resistant to lipotoxicity from hyperlipidemia. During this process, the python circulatory system exhibited sustained hyperlipidemia for 8 weeks. We found python hearts were protected from the negative consequences of high circulating lipids by dynamic oxidative lipid metabolism, a heightened capacity to store fat, and dampened stress kinase responses. These results suggest that Burmese pythons evolved to be protected against the negative cardiac consequences of hyperlipidemia.