Dysbiosis and Gastrointestinal Surgery: Current Insights and Future Research.

Surgery of the gastrointestinal tract can result in deep changes among the gut commensals in terms of abundance, function and health consequences. Elective colorectal surgery can occur for neoplastic or inflammatory bowel disease; in these settings, microbiota imbalance is described as a preoperative condition, and it is linked to post-operative complications, as well. The study of bariatric patients led to several insights into the role of gut microbiota in obesity and after major surgical injuries. Preoperative dysbiosis and post-surgical microbiota reassessment are still poorly understood, and they could become a key part of preventing post-surgical complications. In the current review, we outline the most recent literature regarding agents and molecular pathways involved in pre- and post-operative dysbiosis in patients undergoing gastrointestinal surgery. Defining the standard method for microbiota assessment in these patients could set up the future approach and clinical practice.

The improvement in body composition including subcutaneous and visceral fat reduces ammonia and hepatic encephalopathy after transjugular intrahepatic portosystemic shunt.

BACKGROUND: Sarcopenia and myosteatosis have been associated to a poor prognosis of cirrhosis and to a higher incidence of hepatic encephalopathy (HE). The prognostic implications of visceral and subcutaneous adiposity are less known. AIM: To evaluate the modifications of visceral and subcutaneous adipose tissue after TIPS and to investigate their relationships with the modification of muscle mass and with the incidence of post-TIPS HE. PATIENTS AND METHODS: 35 cirrhotic patients submitted to TIPS were retrospectively studied. The modification of skeletal muscle index (SMI), muscle attenuation (myosteatosis), subcutaneous adipose tissue index (SATI), visceral adipose tissue index (VATI), assessed by CT-scan and plasma ammonia were evaluated before and after a mean follow-up of 19 ± 15 months after TIPS. The number of episodes of overt HE was also recorded. RESULTS: During the follow-up, the mean SMI and muscle attenuation increased significantly; SATI significantly increased while VATI significantly decreased, although not uniformly in all patients. By comparing the patients with or without improvement in their nutritional status after TIPS, MELD remained stable while the number of episodes of overt HE was significantly lower in the patients with improved SMI and in the patients with improved SATI. Finally, inverse correlation was observed between the variation of ammonia and SATI (r = -.40; P < .05). CONCLUSION: In addition to muscle mass, adipose tissue is modified after TIPS. The improvement of subcutaneous adipose tissue as well as of sarcopenia and myosteatosis is associated to the amelioration of cognitive impairment independently of liver function. The correlation between adipose tissue and ammonia modification may suggest an active role of the adipose tissue in the inter-organ ammonia trafficking.