The importance of biological sex in cardiac cachexia.

Cardiac cachexia is a catabolic muscle-wasting syndrome observed in approximately 1 in 10 patients with heart failure. Increased skeletal muscle atrophy leads to frailty and limits mobility, which impacts quality of life, exacerbates clinical care, and is associated with higher rates of mortality. Heart failure is known to exhibit a wide range of prevalence and severity when examined across individuals of different ages and with comorbidities related to diabetes, renal failure, and pulmonary dysfunction. It is also recognized that men and women exhibit striking differences in the pathophysiology of heart failure, as well as skeletal muscle homeostasis. Given that both skeletal muscle and heart failure physiology are in part sex-dependent, the diagnosis and treatment of cachexia in patients with heart failure may depend on a comprehensive examination of how these organs interact. In this review, we explore the potential for sex-specific differences in cardiac cachexia. We summarize advantages and disadvantages of clinical methods used to measure muscle mass and function and provide alternative measurements that should be considered in preclinical studies. In addition, we summarize sex-dependent effects on muscle wasting in preclinical models of heart failure, disuse, and cancer. Lastly, we discuss the endocrine function of the heart and outline unanswered questions that could directly impact patient care.