Mitochondrial-triggered immune responses mechanistically connect drug-induced steatohepatitis and cardiomyopathy associated with nonalcoholic steatohepatitis

Sexual dimorphism in hepatic PPAR alpha and CYP4a12a expression is associated with reduced development of drug-induced non-alcoholic steatohepatitis in female IL-33-/- mice

Males are at higher risk for developing metabolic dysfunction-associated steatohepatitis (MASH) than females; however, mechanisms mediating sexual dimorphism in MASH development are not completely understood. Nutrition-based mouse models suggest that dysregulated fatty acid biosynthesis promotes MASH. Drugs recapitulate MASH without diet variabilities. This brief report investigates associations of sexual dimorphism with male susceptibility to MASH utilizing a drug-induced MASH model and focuses on very-long-chain fatty acid biosynthesis pathways. We assessed male and female mouse livers at 5 and 15 weeks following MASH induction by immunizations and age-matched un-immunized controls utilizing Western blot. Our results suggest that PPAR alpha and CYP4a12a protect females, while CYP4v2 does not protect males from MASH development. Our results have important implications for understanding sexual dimorphism in the pathogenesis of MASH.

Mechanisms of nonalcoholic steatohepatitis-associated cardiomyopathy: key roles for liver-heart crosstalk

PURPOSE OF REVIEW

Nonalcoholic steatohepatitis (NASH) is a multisystem disease that affects not only the liver but also heart, pancreas, and kidney. We currently lack a comprehensive understanding of mechanisms responsible for the development of NASH-associated cardiomyopathy or the influence of sex on pathophysiology. There is a critical need to address these gaps in knowledge in order to accelerate translation of knowledge into clinical practice.

RECENT FINDINGS

NASH and cardiovascular disease share common risk factors such as chronic inflammation, hyperlipidemia, and insulin resistance. Early cardiac dysfunction in NASH that is independent of obesity or other cardiometabolic risk factors suggests roles for liver-heart crosstalk in disease pathogenesis. Inflammation is a driving force in the pathogenesis of NASH, and it is likely that 'spill over' of NASH inflammation contributes to the development of cardiomyopathy. However, molecular and cellular mechanisms that mediate NASH-associated cardiomyopathy remain unclear because of inherent limitations of experimental models. Even so, recent studies implicate inflammatory, metabolic, and physiologic mechanisms that enhance our understanding of NASH-associated cardiomyopathy and the role of liver-heart crosstalk.

SUMMARY

An innovative, detailed, and mechanistic understanding of NASH-associated cardiomyopathy is relevant to public health and will be fundamental for the comprehensive care of these patients.