Restoration of dysbiotic human gut microbiome for homeostasis.

The human microbiome is a complex and dynamic ecosystem, and the imbalance of its microbial community structure from the normal state is termed dysbiosis. The dysbiotic gut microbiome has been proved to be related to several pathological conditions like Inflammatory Bowel Disease (IBD), Irritable Bowel Syndrome (IBS), Colorectal Cancer (CRC), etc., and several other extra-intestinal conditions like Type 1 & 2 diabetes, obesity, etc. The complex gut microbial ecosystem starts to build before the birth of an individual. It is known to get affected by several factors such as birth mode, individual lifestyle, dietary practices, medications, and antibiotics. A dysbiotic microbiome can potentially hamper host homeostasis due to its role in immune modulation, metabolism, nutrient synthesis, etc. Restoration of the dysbiotic gut microbiome has emerged as a promising aid and a better therapeutic approach. Several approaches have been investigated to achieve this goal, including prebiotics and probiotics, Fecal Microbiota Transplantation (FMT), extracellular vesicles, immune modulation, microbial metabolites, dietary interventions, and phages. This review discusses the various factors that influence the human microbiome with respect to their cause-effect relationship and the effect of gut microbiome compositional changes on the brain through the gut-brain axis. We also discuss the practices used globally for gut microbiome restoration purposes, along with their effectiveness.