Инфекция и иммунитет (Jan 2017)
EFFECT BY INTESTINAL MICROBIOM ON THE PROGRESSION OF VIRAL HEPATITIS
Abstract
According to the modern concepts an intestinal microbiome has a significant effect on the functioning of the whole body including the immune system, digestive tract and liver in particular. This review displays current understanding of the intestinal microbiome impacting on the progression of chronic viral hepatitis caused by HCV- and HBV-infection, as well as changes in bowel microbiocenosis features depending on the duration of chronic process in the liver. It is indicated that chronic hepatitis to cirrhosis progression is accompanied by Bifidobacterium and strains of lactic acid (Lactobacillus, Pediococcus, Leuconostoc, Weissella) number decreasing and overgrowth of opportunistic species such as Enterococcaceae, Veillonellaceae, Enterobactericeae, Candida spp., Clostridia spp. This phenomena caused by PAMPs entry into the bloodstream including various types of toxins playing a role in liver immune inflammation processes progression. Thus patients with HBV and HCV infection are increased the number of CD4+, CD25+ in the blood and liver significantly, FOXP3+ Treg cell providing an immunosuppressive effect, and the function of specific CD8 lymphocytes is reduced and insufficient leveling virus significantly. Microbial imbalance has a negative effect on the biosynthesis of bile acids and sterolbiom functioning of our body as a result of changes in the balance between Bacteroides/Firmicutes, overgrowth of pathogenic and opportunistic Enterobacteriaceae, Veillonellaceae, Alcaligeneaceae and Porphyromonadaceae, Clostridium cluster XIVa, Helicobacter spp. and Clostridium difficile. These toxins formation and various carcinogenic metabolites from these strains leads to the inflammation development in the intestines and as a consequence to the progression of the inflammatory process in the liver. In turn, the reduction in the bacteria number producing short-chain fatty acid contributes to intestinal colonization by pathogenic representatives Gracilicutes (Salmonella, Shigella, enterohaemorrhagic E. coli) and Firmicutes (Clostridia), the toxins having a direct toxic effect on the liver. It is examined a little-studied question about a possible cofactor effect of enteric viruses (rotavirus, adenovirus, poliovirus type 1, Coxsackie virus, ECHO) and bacteria (Shigella, Salmonella, diarrheagenic E. coli, C. jejuni) on the progression of chronic hepatitis. In view of the above, it is necessary to study in further detailed the influence of the intestinal microbiome on the progression of chronic hepatitis HBV/HCV etiology in order to develop a comprehensive approach to treatment and reduce the risk of adverse outcomes in patients.
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