Gut microbiota and host gastrointestinal-immune ecosystem

The gut microbiota and host gastrointestinal-immune ecosystem represent a complex symbiotic relationship between trillions of microorganisms and the host's mucosal immune system. This ecosystem is critical for maintaining physiological homeostasis, as the microbiota aids in the digestion of complex carbohydrates, synthesizes essential vitamins like B12 and K, and provides a competitive barrier against pathogenic colonization (Thursby & Juge, 2017, Biochem J). The host immune system must maintain a delicate balance, distinguishing between commensal organisms and potential threats through the induction of regulatory T cells and the secretion of immunoglobulin A (Belkaid & Hand, 2014, Science). Dysregulation of this balance, known as dysbiosis, is implicated in a wide range of pathologies, including inflammatory bowel disease (IBD), metabolic disorders, and systemic autoimmune conditions (Lynch & Pedersen, 2016, NEJM). Therapeutic interventions targeting this system include probiotics, prebiotics, and fecal microbiota transplantation (FMT), which aim to restore a healthy microbial composition. Furthermore, the gut microbiota significantly influences the efficacy and toxicity of various drugs, most notably enhancing the response to cancer immunotherapies such as PD-1/PD-L1 checkpoint inhibitors (Gopalakrishnan et al., 2018, Science).

Other names

Gut microbiomeIntestinal microbiotaGut-immune axisGastrointestinal-immune systemCommensal microbiota

Modulation of microbial diversity and composition, production of metabolites like short-chain fatty acids (SCFAs), and regulation of host mucosal immune cell populations such as regulatory T cells (Tregs) and Th17 cells.