Potato glycoalkaloids adversely affect intestinal permeability and aggravate inflammatory bowel disease.

BACKGROUND

Disruption of epithelial barrier integrity is important in the initiation and cause of inflammatory bowel disease (IBD). Glycoalkaloids, solanine (S), and chaconine (C) are naturally present in potatoes, can permeabilize cholesterol-containing membranes, and lead to disruption of epithelial barrier integrity. Frying potatoes concentrates glycoalkaloids. Interestingly, the prevalence of IBD is highest in countries where fried potatoes consumption is highest.

OBJECTIVE

To further understand the role of potato glycoalkaloids on intestinal barrier integrity, we examined the effect of varying concentrations of solanine and chaconine on intestinal permeability and function.

METHODS

Solanine (0-50 microM), chaconine (0-20 microM), or a 1:1 mixture (0-20 microM) were exposed to T84 cultured epithelial monolayers for varying periods of time to determine concentration response effect on epithelial permeability. Next, a 1:1 mixture (5 microM) of solanine-to-chaconine (C:S) was exposed to sheets of normal murine small intestine, mounted in Ussing chambers, from control and interleukin-10 gene-deficient mice to determine whether glycoalkaloids affected intestine from mice with a genetic predisposition for IBD greater than controls. Finally, the effects of glycoalkaloids on colonic histologic injury were examined in mice orally fed amounts of glycoalkaloids that would normally be consumed in a human diet.

RESULTS

Glycoalkaloids embedded and permeabilized the T84 monolayer epithelial membrane bilayer in a concentration-dependent fashion, with C:S > C > S. In vitro Ussing chamber experiments also illustrated a concentration-dependent disruption of intestinal barrier integrity in animals with a genetic predisposition to develop IBD, but not in control animals. Similarly, in vivo oral feeding experiments demonstrated that C:S ingestion, at physiologic concentrations, aggravated histologic colonic injury in mice genetically predisposed to developing IBD.

CONCLUSIONS

Concentrations of glycoalkaloids normally available while eating potatoes can adversely affect the mammalian intestine and can aggravate IBD.