Changes in Carcinogenic Heterocyclic Amines during in vitro Digestion

The Human Gut Microbiota: A Key Mediator of Osteoporosis and Osteogenesis

An expanding body of research asserts that the gut microbiota has a role in bone metabolism and the pathogenesis of osteoporosis. This review considers the human gut microbiota composition and its role in osteoclastogenesis and the bone healing process, specifically in the case of osteoporosis. Although the natural physiologic processes of bone healing and the pathogenesis of osteoporosis and bone disease are now relatively well known, recent literature suggests that a healthy microbiome is tied to bone homeostasis. Nevertheless, the mechanism underlying this connection is still somewhat enigmatic. Based on the literature, a relationship between the microbiome, osteoblasts, osteoclasts, and receptor activator of nuclear factor-kappa-Β ligand (RANKL) is contemplated and explored in this review. Studies have proposed various mechanisms of gut microbiome interaction with osteoclastogenesis and bone health, including micro-RNA, insulin-like growth factor 1, and immune system mediation. However, alterations to the gut microbiome secondary to pharmaceutical and surgical interventions cannot be discounted and are discussed in the context of clinical therapeutic consideration. The literature on probiotics and their mechanisms of action is examined in the context of bone healing. The known and hypothesized interactions of common osteoporosis drugs and the human gut microbiome are examined. Since dysbiosis in the gut microbiota can function as a biomarker of bone metabolic activity, it may also be a pharmacological and nutraceutical (i.e., pre- and probiotics) therapeutic target to promote bone homeostasis.

Analysis of in vitro digestion using human gut microbiota in adult and elderly individuals

In vitro human digestion models are widely used to determine the digestibility of bioactive substances and to perform drug delivery analyses. To develop the most accurate in vitro human digestion model reported to date, we simulated all digestion conditions, including pH and digestion time, with changes in the amount of digestive enzymes, motility, and proportion of human gut microbiota in adult and elderly individuals. Using this newly developed model, the digestibility of vitamin E emulsified by lard was found to be significantly different between adults and the elderly. Therefore, this model can accurately simulate oral, gastric, and intestinal (with gut microbiota effects) digestion of bioactive substances and can aid in analyzing drug delivery in adults and elderly individuals.