The colon is actively implicated in intestinal
infections not only as a target of enteric pathogens and their products but also as a target organ for treatment. In the presence of
diarrhea, both of osmotic and secretory nature, the colon reacts with homeostatic mechanisms to increase ion absorption. These mechanisms can be effectively exploited to decrease fluid discharge. A model of intestinal
infections using rotavirus (RV) in colonic cells was set up and used to define a dual model of secretory and osmotic
diarrhea in sequence. Using this model,
antidiarrheal drugs were tested, namely
zinc and the
enkephalinase inhibitor
racecadotril.
Zinc was able to decrease the enterotoxic activity responsible for secretory
diarrhea. It also inhibited the cytotoxic effect of RV. The mechanism of
zinc was related at least in part to the activation of MAPK activity, but also a direct
antiviral effect was observed.
Racecadotril showed a potent and selective inhibition of active secretion, being particularly effective in the first phase of RV
diarrhea. The use of drugs active at the colonic level, therefore, offers effective options to treat intestinal
infections in childhood. In addition, the colon is the natural site of colonic microflora, a target of probiotic
therapy, which is the first line of approach recommended by the European Society for Paediatric Gastroenterology, Hepatology and Nutrition to treat infectious
diarrhea.