In vivo and in vitro efficacy of octreotide for treatment of enteric cryptosporidiosis.

Previous evidence suggested a role of enterotoxin in the pathophysiology of cryptosporidiosis. If so, antisecretory drugs should be effective in reducing diarrhea. We evaluated the in vivo and in vitro efficacy of octreotide, which possesses antisecretory effects, for cryptosporidial diarrhea. Two children with severe cryptosporidial diarrhea were treated with octreotide. The volume modifications and chemical composition of stools were determined. Fecal supernatant was added to Caco-2 cell monolayers mounted in Ussing chambers with or without serosal octreotide and electrical parameters were monitored. Octreotide was effective in reducing the stool volume and fecal Na+ concentration. Fecal supernatant induced an enterotoxin-like increase in transepithelial potential difference. Octreotide induced a dose-dependent decrease in basal potential difference, consistent with an absorptive effect. In cells pretreated with octreotide, fecal supernatant induced an increase in the potential difference, whose magnitude and duration were significantly reduced compared to untreated cells. These results provide in vivo and in vitro evidence for the secretory nature of cryptosporidial diarrhea and for the efficacy of octreotide through a direct interaction with the enterocyte.