Commentary on the effects of RANKL inhibition on bone mass and muscle strength?J Diabetes Investig 2019JD
Osteoporosis and sarcopenia, or interpreted as osteo-sarcopenia, is a major public health problem and the social economic burden in many countries and also in Asia. It's the most common metabolic bone and muscle disorder in elderly, especially in female. Osteoporosis is a pathologic process by a decrease in bone mass and deterioration in skeletal microarchitecture, accompanied by a progressive and generalized loss of muscle mass with muscle strength or a loss of physical performance with increasing rates of disability, poor mobility, frailty, and even the mortality and morbidity. Bone and muscle have been increasingly recognized as interacting tissues as a result of the mechanical effects of muscle loading on bone function. Some endocrine disorders are also related to osteoporosis and sarcopenia, e.g. diabetes mellitus, thyroid dysfunction, vitamin D deficiency, insulin-like growth factor-1, growth hormone, sex hormones, cytokine imbalance, obesity and malnutrition. Bone and muscle dysfunction, also characterized by the predominant atrophy of type II fibers together with smaller and fewer mitochondria, are associated with several genetic polymorphisms of the genes such as α-actinin 3, proliferator-activated receptor gamma coactivator 1-alpha, glycine-n-acyltransferase, methyltransferase-like 21C, myostatin, and myocyte enhancer factor 2C (Fig.1). Therefore, the denervation of single muscle fibers reduces type-II fibers, which are gradually replaced by type-I fibers and adipose tissue.