Introduction to host microbiome symbiosis in health and disease

Abstract

Humans share a core intestinal microbiome and yet human microbiome differs by genes, species, enterotypes (ecology), and gene count (microbial diversity). Achievement of microbiota metagenomic analysis has revealed that the microbiome gene count is a key stratifier of health in several immune disorders and clinical conditions. We review here the progress of the metagenomic pipeline analysis, and how this has allowed us to define the host–microbe symbiosis associated with a healthy status. The link between host–microbe symbiosis disruption, the so-called dysbiosis and chronic diseases or iatrogenic conditions is highlighted. Finally, opportunities to use microbiota modulation, with specific nutrients and/or live microbes, as a target for personalized nutrition and therapy for the maintenance, preservation, or restoration of host–microbe symbiosis are discussed.

Interconnections between the Oral and Gut Microbiomes: Reversal of Microbial Dysbiosis and the Balance between Systemic Health and Disease

“…Another consequence of dysbiosis is increased intestinal permeability, which is associated with the high-fat diets seen in the Bacteroides enterotype. Individuals with this enterotype are known to have low microbial gene richness (LGR), which is heavily associated with chronic systemic conditions and an increased risk of morbidities [24], whereas individuals with the Prevotella enterotype have a much higher gene richness (HGR). LGR boosts the proportion of pathobionts, resulting in increased intestinal permeability and inflammation [24].…”

“…Individuals with this enterotype are known to have low microbial gene richness (LGR), which is heavily associated with chronic systemic conditions and an increased risk of morbidities [24], whereas individuals with the Prevotella enterotype have a much higher gene richness (HGR). LGR boosts the proportion of pathobionts, resulting in increased intestinal permeability and inflammation [24]. It is also associated with increased mucus degradation, decreased butyrate-formation, higher oxidative stress, and reduced methane and hydrogen production, suggesting an inflammatory microbiota [25].…”

The Role of Gut Microbiota on Cholesterol Metabolism in Atherosclerosis

“…The microbiota is a hidden organ of the human system establishing homeostasis or disease in an individual. In a healthy state, these interactions are largely symbiotic and influence a host’s nutrition, metabolism, energy, and immunity [ 1 ]. Modern methodologies have given insights into the role of the gut in many processes such as the absorption, distribution and extraction of nutrients, synthesis of vitamins, immunomodulation, and protection against pathogens [ 2 ].…”

Contribution of Gut Microbiota to Immunological Changes in Alzheimer’s Disease

“…Gut microbiota can affect host immunity via the release of metabolites and toxins. Microbial misbalance can lead to systemic inflammation in the gut and affect the gut barrier function, increasing permeability and the entry of bacteria, metabolites and toxins into the circulation ( 22 ) ( Figure 1 ). Interestingly, gut permeability was recently reported to be increased in a cohort of dementia patients together with the occurrence of systemic inflammation ( 23 ).…”