Effects of the ACE2 inhibitor GL1001 on acute dextran sodium sulfate-induced colitis in mice.

Angiotensin-converting enzyme 2 (ACE2) is expressed in gastrointestinal tissue. Previous studies of GL1001, a potent and selective ACE2 inhibitor, have revealed anti-inflammatory activity in the mouse digestive tract. We hypothesized that GL1001 might also produce beneficial effects in a mouse DSS model of inflammatory bowel disease. Female mice were used for study. Animals were treated for 5 days with 5% DSS in the drinking water to induce colitis. For the following 9 days, animals were treated twice daily with GL1001 (30, 100, 300 mg/kg, s.c.), sulfasalazine (150 mg/kg, p.o.), or vehicle. Throughout the experiment, body weight, rectal prolapse, stool consistency, and fecal occult blood were monitored. At termination, colon length, histopathology, and myeloperoxidase activity were assessed. High-dose GL1001 ameliorated DSS-induced disease activity, including rectal prolapse and intestinal bleeding. The most robust effect of GL1001 was observed 48-96 h post DSS treatment and was comparable in magnitude to that of sulfasalazine. Colon pathology and myeloperoxidase activity were also markedly attenuated by high-dose GL1001 treatment, with the most profound effects observed in the distal segment. The findings support the previously observed anti-inflammatory effects of ACE2 inhibition in gastrointestinal tissue and suggest that GL1001 may have therapeutic utility for inflammatory bowel disease.