Bidirectional Interaction Between the Gastrointestinal System and the Kidney: Pathophysiological and Clinical Perspective.

The gastrointestinal (GI) system and the kidneys, though anatomically separate, are functionally interconnected through shared responsibilities in maintaining fluid-electrolyte balance, acid-base homeostasis, immune regulation, and hormonal signaling. Disruptions in one system often lead to secondary complications in the other, highlighting the need for a comprehensive understanding of their bidirectional interactions. Kidney involvement in GI diseases commonly results from mechanisms such as fluid loss, malabsorption, systemic inflammation, and exposure to toxins, as seen in conditions like inflammatory bowel disease (IBD), celiac disease, liver failure, and enteric infections. Conversely, GI complications frequently arise in the context of chronic kidney disease (CKD), dialysis, and immunosuppressive therapies post-transplantation, manifesting as symptoms including uremic gastropathy, anorexia, and enteropathy. This review explores these interactions under two main categories: renal complications of GI diseases and GI manifestations of kidney disorders. It also discusses the underlying pathophysiological mechanisms and clinical implications, emphasizing the importance of an integrated, multidisciplinary approach. By highlighting current knowledge gaps, the review aims to foster future research in this complex and clinically significant area. Understanding these bidirectional interactions can inform individualized patient care and improve outcomes in both GI and renal disease contexts.