Fig. 2

Speculation on the gut–liver axis after schistosome infections. The liver transports bile salts and antimicrobial molecules to the intestinal lumen through the biliary tract. This process maintains gut eubiosis by controlling unrestricted bacterial overgrowth. Bile salts also act as important signaling molecules via nuclear receptors to modulate hepatic bile acid synthesis, glucose metabolism, lipid metabolism, and energy utilization from diet. Conversely, gut products, such as host and/or microbial metabolites and microbial-associated molecular patterns, translocate to the liver via the portal vein and influence liver functions. Additionally, systemic circulation extends the gut–liver axis by transporting liver metabolites from dietary, endogenous, or xenobiotic substances to the intestine through the capillary system. Owing to this medium of transport and ease of diffusion of systemic mediators across blood capillaries, these factors could affect the intestinal barrier positively (for example, butyrate) or negatively (for example, acetaldehyde)