Current knowledge about the connection between health status and gut microbiota from birth to elderly. A narrative review.

Kastriot Haxhirexha ,Luigì Santacroce ,Skender Topi ,Adrian Man ,Ioannis Alexandros Charitos

doi:10.52586/4930

Abstract

The human body is colonized from the birth by a large number of microorganisms. This will constitute a real "functional microbial organ" that is fundamental for homeostasis and therefore for health in humans. Those microorganisms. The microbial populations that colonize humans creating a specific ecosystem they have been collectively referred to as "human microbiota" or "human normal microflora". The microbiota play an important pathophysiological role in the various locations of the human body. This article focuses on one of the most important, that is the enteric microbiota. The composition (quantitative and qualitative) of microbes is analyzed in relation to age and environment during the course of human life. It also highlights eubiosis and dysbiosis as key terms for its role in health and disease. Finally, it analyzes its bi-directional relationship with the microbiota of the lungs, skin and that of the brain, and consequently for the whole central and peripheral nervous system for the maintenance of health in the human body.

Highlights

The amount of germs can be different along the digestive system, from low concentrations for the stomach, duodenum, jejunum and ileum to high concentrations in the colon
The germ-free model (GF) concept, is based on the fact that during the perinatal life the fetus lives in a sterile context and subsequently with the procedure of a nonvaginal but surgical delivery no longer has the opportunity the newborn to have a colonization of the microorganisms present in the mother that constitute the first microbiota development
According to clinical studies conducted in recent years, changes in the composition of gut microbiota is associated with a number changes in the normal microbiological synthesis of the enteric biomass can present a number of serious pathological conditions such as low immune system health, allergy, irritable bowel syndrome (IBS), autoimmune diseases such as idiopathic inflammatory disease, diabetes, weight gain and obesity, asthma, and chronic sinusitis, gastroesophageal reflux disease, constipation or diarrhea, dermatological problems, mental health disorders, Alzheimer’s disease and other [1, 16, 24]

Summary

Human gut microbiota composition

The amount of germs can be different along the digestive system, from low concentrations for the stomach, duodenum, jejunum and ileum to high concentrations in the colon. The organism with its immune system tolerates at the intestinal level all antigens that can help it (such as food, Simbiotic bacteria) and recognize its action against pathogenic microorganisms. The colon being a mostly microaerophilic or oxygen-free environment, most microbes are anaerobic Within this microbiota are mostly overrepresented the Bacteroides, Gram-positive sporigens (such as Ruminococcus, Eubacterium, Bifidobacterium, Peptostreptococcus, and others) and Gram-positive bacilli are mainly represented by the genus Clostridium. The composition of the microflora is influenced mainly by age, environmental factors and the homeostasis of the immune system. Bacteroidetes predominate in newborns, while over time the composition changes gradually and in the elderly the species of the genus Firmicutes predominate (Fig. 4) [6, 12,13,14]

The evolution of microbiota from birth to old age

Microbial balance against colony development by pathogens

The intestinal microbiota in health

The relationship of the enteric microbiota on diseases

Conclusions

Findings

13. References