GPBAR1 and Protein-losing enteropathy: We delineate two principal pathological profiles: (1) microbial collapse, characterized by secondary bile acid (SBA) depletion and compromised farnesoid X receptor (FXR) and Takeda G protein-coupled receptor 5 (TGR5) signaling, which exacerbates inflammation in chronic enteropathy (CE), protein-losing enteropathy (PLE), and exocrine pancreatic insufficiency (EPI); and (2) hepato-biliary spillover, wherein host-induced dysfunction results in primary bile acid (PBA) excess.