Effect of propranolol on the factors promoting bacterial translocation in cirrhotic rats with ascites

Bacterial translocation appears to be an important mechanism in the pathoge nesis of spontaneous infections in cirrhosis, Cirrhotic patients are common ly treated with beta-adrenoceptor blockers, but the impact of this treatmen t in the factors promoting bacterial translocation has not been investigate d. This study was aimed at investigating in cirrhotic rats with ascites the effect of propranolol on intestinal bacterial load, transit, and permeabil ity of the bowel and on the rate of bacterial translocation. Bacterial tran slocation to mesenteric lymph nodes and intestinal bacterial overgrowth, pe rmeability (urinary excretion of Tc-99m-diethylenetriaminepentaacetic acid [ Tc-99m-DTPA]), and transit (geometric center ratio of Cr-51) were assesse d in 29 rats with carbon tetrachloride (CCl4) cirrhosis and 20 controls. Th ese variables were then measured in 12 placebo- and in 13 propranolol-treat ed ascitic cirrhotic rats. Bacterial translocation was present in 48% of th e cirrhotic rats and in none of the controls. Cirrhotic rats with intestina l bacterial overgrowth had a significantly higher rate of translocation and slower intestinal transit than those without it. Among the 15 rats with ov ergrowth and a Tc-99m-DTPA excretion greater than 10%, 15 had translocation and 2 had bacterial peritonitis, Only 1 of the 14 rats with either intesti nal overgrowth or a Tc-99m-DTPA excretion greater than 10% presented transl ocation. Compared with the placebo group, propranolol-treated animals had s ignificantly lower portal pressure, faster intestinal transit, and lower ra tes of bacterial overgrowth and translocation. In ascitic cirrhotic rats, b acterial translocation results from intestinal overgrowth and severe damage to gut permeability. In this setting, intestinal overgrowth is associated with intestinal hypomotility, Propranolol accelerates the intestinal transi t, decreasing the rates of bacterial overgrowth and translocation.