The Role of Microbiota on the Intestinal Barrier
Introduction
The functions gut Microbiota performs in intestinal barrier under normal condition differs with the one under abnormal composition of Microbiota. The gut barrier acts as a selectively permeable barrier between the internal host environment and the outside world. Under steady state, Microbiota’s role on intestinal barrier is biologically helpful. However, in imbalance condition, the Microbiota impacts the intestinal barrier negatively causing malfunctioning and disease.
Normal Condition
A normal level of Microbiota in the gut facilitates the biological function of the intestinal barrier. Firstly, Microbiota contributes in the maturation of the intestinal barrier structure and regulates its permeability. Permeability is regulated by maintaining the integrity of the epithelial layer which makes up the barrier. Secondly, Microbiota improves the barrier’s immune system. Gut Microbiota contains different species of known bacteria. The bacteria produced by Microbiota produces Treg cells, which suppress pathological inflammation. The inflammatory suppression in return induces host tolerance in non-host cells, therefore, improving immune development under normal condition (Natividad, & Verdu 2013). The bacteria perform an essential role in maintaining immunity and metabolic homeostasis by protecting the intestinal barrier against pathogens. Consequently, the direct interaction of host-gut bacteria, the immune system, and the host epithelium maintain a good intestinal homeostasis.
Also, in a stable condition of the Microbiota, the anti-inflammatory characteristic of Microbiota facilitates and challenges the host immune system at a suitable level. The appropriate level keeps the immune defense mechanisms alert and produces regulatory signals. The regulatory signs then help to induce tolerance to commensal Microbiota. The usual composition of gut microbiome enhances resistance against colonization through producing microorganisms from the external environment. The resistance is provided through various ways such as secretion of anti-microbial products, deploying bacteriophage, and support of barrier integrity. Therefore, the core role of the gut Microbiota includes building a good immune system for the barrier, developing the structure of the barrier, and maintaining a normal permeability.
Abnormal Condition
Imbalance Microbiota may result into malfunctioning of the Intestinal Barrier. Abnormal composition of the Microbiota may be caused by immune cells and external environmental factors such as diet and antibiotics. For instance, if a certain antibiotic is induced to the body, the composition of Microbiota is disrupted and as a result the occupancy of the microorganisms (including the bacteria which fight pathogens) then the delicate homeostasis is altered. The disruption of the delicate homeostasis between the beneficial and the harmful microorganism leads to inflammatory pathologies (Sabatino et al. 2014). Imbalance composition of the Microbiota reverses the fundamental roles performed by the gut microbiome due to the increased levels of microorganisms.
In addition to imbalance Microbiota losing its ability to support intestinal homeostasis, it also results in intestinal inflammatory. Altered microbiome composition is related to other intestinal diseases and not only inflammatory diseases. The abnormal composition facilitates intestinal dysbiosis, which is described with man gastrointestinal diseases such as celiac diseases, and irritable bowel syndrome, among others. The altered composition of Microbiota in the gut increases the level of gamma-proteobacteria, which consists of high inflammatory, causing the loss of gut integrity.
Imbalance composition of the gut Microbiota also causes impairment of the epithelial layer resulting in leakage. The leakage is referred to as hyperpermeability, which allows excessive content through the barrier and exposes the intestinal content to infectious microorganisms. For instance, the exposure of the intestinal content to the host periphery gives the host the potential of causing burning in the intestinal wall. With altered composition of Microbiota the intestinal homeostasis lowers, and the resistance against host epithelium becomes weak, reducing the defense mechanisms. Generally, abnormal composition of the Microbiota weakens the gut immune system, causes high permeability of the barrier and demolishes the structure of the intestinal barrier.
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