Gastro-vascular and micro-vascular changes in chronic murine schistosomiasis mansoni-response to propranolol.

Histopathologic study of the gastric wall of mice infected with Schistosoma mansoni was carried out at 8, 12, 16 and 20 weeks post-infection (p.i.). The gastric vascular structures were more sensitive to injury with the progression of liver disease than the glandular cells, with marked submucosal edema and thickening of submucosal and subserosal vessels. By transmission electron microscopy, the mucosal microvessels had thickened basement membrane and conspicuous endothelial cells with granular cytoplasm thrown into numerous intraluminal microprojections and with increased number and size of pinocytotic vesicles. When propranolol was administered orally as 20 mg/kg daily doses for two weeks at 6, 10, 14 and 18 weeks p.i., a striking regression of gastro vascular and micro-vascular changes has been observed, particularly with early drug therapy. Based on the present study, it can be concluded that "structural autoregulation" of gastric vasculature to the emerging portal hypertension in chronic murine schistosomiasis mansoni, is a dynamic process that could be reversed by propranolol therapy. This response could, possibly, improve gastric mucosal perfusion and functional abnormalities which may predispose the gastric mucosa to severe damage or hemorrhage.