The microbiota-gut-bone axis and bone health

Abstract

The gastrointestinal tract is colonized by trillions of microorganisms, consisting of bacteria, fungi, and viruses, known as the “second gene pool” of the human body. In recent years, the microbiota‐gut‐bone axis has attracted increasing attention in the field of skeletal health/disorders. The involvement of gut microbial dysbiosis in multiple bone disorders has been recognized. The gut microbiota regulates skeletal homeostasis through its effects on host metabolism, immune function, and hormonal secretion. Owing to the essential role of the gut microbiota in skeletal homeostasis, novel gut microbiota‐targeting therapeutics, such as probiotics and prebiotics, have been proven effective in preventing bone loss. However, more well‐controlled clinical trials are still needed to evaluate the long‐term efficacy and safety of these ecologic modulators in the treatment of bone disorders.

Bacillus subtilis-Based Probiotic Improves Skeletal Health and Immunity in Broiler Chickens Exposed to Heat Stress

“…Studies have elucidated how the gut microbiota and its metabolites influence bone metabolism via interactions with host metabolic, immune, and neuroendocrine systems through multiple pathways, including the microbiota-gut-brain axis, the microbiota-gutimmune axis, and the microbiota-gut-bone axis [5,54,55,158,159]. Alterations in microbiota homeostasis contribute to pathological bone loss and related diseases, such as osteoporosis (OP), in humans and various experimental animals by reducing nutrient and mineral resorption, increasing osteoclast proliferation, altering bone immune status, and/or changing the metabolisms of serotonin, corticosterone, and sex hormones [160][161][162].…”

“…The gut microbiota (gut flora) plays a critical role in preserving host health by releasing various metabolites to stimulate hosts' neural, endocrine, and immune systems [1][2][3][4][5][6][7]. However, microbial functions can be changed markedly by multiple factors, such as lifestyle (living environments), nutrition and health condition (pathophysiological disorders), life-stage (age), and medical substances in humans [8][9][10][11][12][13][14][15].…”

Effect of a synbiotic supplement as an antibiotic alternative on broiler skeletal, physiological, and oxidative parameters under heat stress

“…It has been reported previously that broilers fed with the SYN product ( Wideman et al., 2012 ) have a lower incidence of bacterial chondronecrosis with osteomyelitis lameness as well as lower incidence of femoral head transitional degeneration and tibial head necrosis due to prevention of gut bacterial translocation and hematogenous distribution. The direct link between prebiotic and probiotic supplements and bone health has been demonstrated in a variety of animal models (zebrafish, rodents, and chicken) and humans ( Scholz-Ahrens et al., 2007 ; Tu et al., 2021 ). In this aspect, it could be argued that broilers fed with the SYN have improved skeletal health under both TN and HS conditions.…”

Role of Dietary Supplements and Probiotics in Modulating Microbiota and Bone Health: The Gut-Bone Axis

“…Interestingly, Actinomyces might be involved in the development of osteonecrosis of the jaw, whereas Firmicutes contribute to an estrogen analogue conversion, with anabolic effects on bone [ 36 ]. Interestingly, bacterial populations vary in osteopenia, primary osteoporosis, or secondary osteoporosis, but the relationship and prevalence between microbial species under these conditions are still debated [ 37 ]. To date, several substances—including trimethylamine N -oxide, N -acetyl-mannosamine, l -threonate, l -lysine, and short-chain fatty acids (SCFAs)—have been shown to modulate the gut microbiota, with a consequent impact on bone [ 37 , 38 ].…”