Effect of captopril on transplanted schistosome egg granulomas in skin

Groups of athymic nude (nu/nu) and littermate (nu/+) mice received transplants into skin of hepatic egg granulomas isolated from Schistosoma mansoni-infected nu/+ mice. Some were fed captopril, an angiotensin-converting enzyme inhibitor, and other animals served as controls. Lesions were removed at 2, 4, and 6 weeks after implantation and prepared for light and electron microscopy. The number of new egg granulomas repopulated by recipient cells was compared by counting more than 100 eggs per specimen, randomly, double blind, and the effects of captopril on developing granulomas were determined. Results in nude mice indicated a trend for increasing granuloma takes with time in captopril-treated animals compared to controls, especially in mice who started therapy 2 weeks after transplantation. In nu/+ recipients the differences were more striking and statistically significant at 2 and 6 weeks after grafting. The granulomas in treated mice in both groups were larger than those in controls, but the cellular composition in the granulomas that developed were similar. New granulomas consisted mainly of eosinophils and mixed-function macrophages, although some purely secretory macrophages also were seen. The findings demonstrate that captopril ingestion enhanced granulomatous inflammation induced by skin transplantation of schistosome egg granulomas and significantly increased isograft takes. The results may have relevance for treating cutaneous diseases like sarcoidosis with captopril.