Factors associated with impaired hypoglycemia awareness in patients with type 2 diabetes in Korea: a cross-sectional study.

The human gut microbiome produces a diverse array of bioactive metabolites, including short-chain fatty acids (SCFA), tryptophan derivatives, secondary bile acids, and microbial uremic toxins, that enter host circulation through portal and systemic pathways and influence host physiology. Emerging experimental evidence suggests that many of these metabolites directly regulate mitochondrial function, including electron transport chain (ETC) activity, oxidative phosphorylation, mitochondrial membrane potential, and mitochondrial biogenesis. These molecules arise through several biological pathways, including bacterially synthesized metabolites that are produced directly by microbial metabolism (e.g., butyrate (BTY) and propionate (PPA)), microbial structural components released during bacterial growth or lysis (e.g., lipopolysaccharide), and host–microbe co-metabolites generated through sequential microbial and host enzymatic transformations (e.g., indoxyl sulfate, -cresol sulfate). These observations support the concept of a microbiome–mitochondria axis, in which microbial metabolic activity influences host cellular energetics through direct modulation of mitochondrial function. Viewed across classes, these effects repeatedly converge on a small set of mitochondrial control nodes, particularly ETC activity, oxidative stress, biogenesis, and mitophagy, which provides the organizing logic for this review. Despite growing interest in this biological interface, to our knowledge, no systematic review has comprehensively synthesized the effects of gut-derived metabolites on direct mitochondrial endpoints across major metabolite classes. Individual metabolite classes have been reviewed in disease-specific contexts. For example, uremic toxins have been reviewed in chronic kidney disease, bile acids in liver disease, and SCFAs in colorectal physiology. However, an integrated synthesis spanning all ten classes with standardized quality assessment has been lacking. Because mitochondria integrate metabolic, inflammatory, and signaling inputs, these pathways have implications for metabolic syndrome, chronic kidney disease, cardiovascular disease, and brain disorders.