Caloric restriction without malnutrition (CR) is the most robust and reproducible way to extend lifespan and delay the onset of age-related diseases, such as hepatic steatosis, insulin resistance and type 2 diabetes (T2D). Unfortunately, the strict dietary regime necessary to achieve the beneficial effects of CR limits the use of this treatment to retard aging and disease in humans and new therapies are required. In this regard, our lab has recently developed a new class of therapeutic agents that are designed to safely promote liver-targeted mitochondrial uncoupling with a wide-therapeutic index. Our second-generation compound in this class is controlled-release mitochondrial protonophore (CRMP) that is functionally liver-targeted and promotes oxidation of hepatic triglycerides by promoting a subtle sustained increase in hepatic mitochondrial inefficiency. While we have previously demonstrated that this agent safely reverses hypertriglyceridemia, fatty liver, and hepatic inflammation/fibrosis in young-adult diet-induced rodent models of obesity, its effects on healthspan and lifespan remain to be determined. Here, we evaluated the impact of CRMP on hepatic steatosis and insulin action in aged 74-week-old male C57BL/6J mice fed a high-fat diet (HFD; 45% fat) for 12 weeks. Specifically, we demonstrate that CRMP treatment significantly reduced liver triglycerides, diacylglycerols, and transaminase levels independently of changes in body weight, whole-body energy expenditure or food intake. Additionally, long-term CRMP treatment reduced fasting plasma glucose concentrations (P <0.05) and improved whole-body insulin responsiveness, as reflected by a marked increase in the glucose infusion rate required to maintain euglycemia during a hyperinsulinemic-euglycemic clamp. Taken together, these studies provide important proof-of-concept data to support the use of liver-targeted mitochondrial uncouplers to promote healthy aging.
L. Goedeke: None. J. Camporez: None. A. Nasiri: None. Y. Wang: None. X. Zhang: None. G.I. Shulman: Advisory Panel; Self; AstraZeneca, Janssen Research & Development, Merck & Co., Inc., Novo Nordisk Inc.. Research Support; Self; Gilead Sciences, Inc..