Intestinal microbiota: a potential target for the treatment of postmenopausal osteoporosis

Postmenopausal osteoporosis (PMO) is a prevalent metabolic bone disease characterized by bone loss and structural destruction, which increases the risk of fracture in postmenopausal women. Owing to the high morbidity and serious complications of PMO, many efforts have been devoted to its prophylaxis and treatment. The intestinal microbiota is the complex community of microorganisms colonizing the gastrointestinal tract. Probiotics, which are dietary or medical supplements consisting of beneficial intestinal bacteria, work in concert with endogenous intestinal microorganisms to maintain host health. Recent studies have revealed that bone loss in PMO is closely related to host immunity, which is influenced by the intestinal microbiota. The curative effects of probiotics on metabolic bone diseases have also been demonstrated. The effects of the intestinal microbiota on bone metabolism suggest a promising target for PMO management. This review seeks to summarize the critical effects of the intestinal microbiota and probiotics on PMO, with a focus on the molecular mechanisms underlying the pathogenic relationship between bacteria and host, and to define the possible treatment options. Osteoporosis: Go with the gut Probiotics may improve treatment of postmenopausal osteoporosis (PMO). In PMO, decreased estrogen levels weaken bones and increase the risk of fracture, usually of the hip, femur, or spine. Complications can be serious, and better prophylactic and treatment options are needed. The intestinal microbial community is known to affect bone formation, suggesting a new treatment avenue. Xuedong Zhou of Sichuan University, Chengdu, China and co-workers reviewed the evidence that probiotics might help combat PMO. They report that in PMO, low estrogen levels decrease microbial diversity and weaken the intestinal lining, opening the door for pathogens and triggering immune responses associated with bone loss. Treatment with probiotics ameliorates these effects, restoring intestinal diversity, normalizing immune responses, and increasing calcium absorption and production of estrogen-like compounds. The authors conclude that probiotics are a promising supplementary treatment for PMO.