Problems and prospects of metabolomic studies in the alteration of the gut microbiome.

The review summarizes existing knowledge on the relationship between certain diseases and alteration (degeneration) of the intestinal microbiome. We consider major microbial metabolites firmly recognized as signaling molecules acting in communication between the microbiome and the host organism. These include short-chain fatty acids, bile acids, amines, amino acids, and their metabolites. Special attention is paid to metabolomic studies of the microbiome in chronic kidney diseases, in particular, immunoglobulin A nephropathy. The arguments supporting a concept of the microbiome of blood, previously considered an exclusively sterile environment in healthy humans, are considered. Metagenomic methods plays a key role in characterization of both the composition and potential physiological effects of microbial communities. The advantages and limitations of metabolomic analysis of blood serum/plasma and feces have been analyzed. Since the potential of clinical studies of the mutual impact of the microbiome-metabolome is limited by genetic and external factors, preclinical studies still employ both germ-free models and models based on the effects of antibiotics. The review considers the problems and prospects of metabolomics in studying the nature and mechanisms of the mutual impact of the microbiome and metabolome.