The interplay of estrogen, gut microbiome, and bone immunity in osteoporosis

Osteoporosis is a global health concern arising from estrogen deficiency, intestinal dysbiosis, and dysregulation of the bone immune system. The absence of estrogen after menopause created environmental changes within the gut, where the microbial growth of the body was disturbed by the endocrine hormone, and inflammation increases due to the gut-bone axis, which leads to heightened bone loss. The gut microbiota, composed of bacteria and their metabolites such as short-chain fatty acids, play a crucial role in bone immune regulation by modulating immune cell function, influencing bone cell activity, and mediating epigenetic modifications. Malfunction of this system, characterized by the activation of immune cells and the imbalance of cytokines, also leads to the development of osteoporosis. Treatment strategies involved the regulation of the dysbiosis of the gut microbiota, reposition estrogen to the body, and immune modulation. The future direction should be the clarification of these interactions between estrogen and intestinal microflora, identification of new therapeutic targets, and personalization of osteoporosis management.