Gut microbiota dysbiosis, circulating microbial genetic traces, and their role in gestational diabetes

Figure 3 Gut microbiota dysbiosis, microbial DNA, and gestational diabetes mellitus. Gut microbiota dysbiosis during pregnancy reduces microbial diversity, weakens intestinal barrier integrity, and facilitates microbial DNA translocation into circulation. Circulating microbial DNA activates immune pathways such as toll-like receptor 9 and cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes, inducing pro-inflammatory cytokines (interleukin-6 and tumor necrosis factor-α) that impair insulin signaling. This immune-metabolic disruption promotes insulin resistance, contributing to the pathogenesis of gestational diabetes mellitus and adverse maternal-foetal outcomes. TNF: Tumor necrosis factor; IL: Interleukin; LPS: Lipopolysaccharides; GDM: Gestational diabetes mellitus.