Microbial Glucuronidase Inhibition Reduces Severity of Diclofenac-Induced Anastomotic Leak in Rats.

Background: The non-steroidal anti-inflammatory drug diclofenac has been associated with intestinal anastomotic leakage, although the underlying pathophysiology is unclear. Previous data suggest that reactivation of biliary diclofenac metabolites by microbial -glucuronidases in the gut plays a role in harming the intestinal mucosa, and that microbiome-targeted glucuronidase inhibition prevents this damage. Here, the microbial glucuronidase inhibitor Inh1 was examined for its ability to reduce diclofenac-induced anastomotic leakage in rats. Methods: Ninety male Wistar rats were allocated to five groups. In the two diclofenac groups, group DCF received diclofenac (3mg/kg per day) and group DCF-Inh1 additionally received 800mcg/kg per day of glucuronidase inhibitor Inh1 solution orally. In non-diclofenac groups, animals received either Inh1 (800mcg/kg per day; group Inh1) solution, the vehicle (methylcellulose; group Veh), or no solution (group Ctrl). All solutions were provided from the day of surgery until sacrifice on day three. Plasma concentrations of diclofenac were determined. Outcomes were anastomotic leakage, leak severity, and anastomotic strength. Results: Anastomotic leak rates were 89% in group DCF and 44% in group DCF-Inh1 (p=0.006). Leak severity was reduced in group DCFic-Inh1 (p=0.029). In non-diclofenac cohorts, mostly minor leakage signs were observed in 25% in group Ctrl, 39% in group Inh1 (0.477), and 24% in group Veh (p=1.000). Bursting pressure and breaking strength were not significantly different. Plasma concentrations of diclofenac were not changed by Inh1. Conclusion: Microbial glucuronidase inhibitor reduces diclofenac-induced anastomotic leakage severity, which suggests a harmful effect of diclofenac metabolite reactivation in the gut. This finding improves the understanding of the pathogenesis of anastomotic leakage.