Comparative effects of A- and B-type proanthocyanidins in the prevention of urinary tract infection in mice

Abstract

Consumption of cranberry (Vaccinium macrocarpum) is widely recommended forprophylaxis against urinary tract infections (UTI) in women. Among cranberry components, A-type proanthocyanins would be implicated in these preventive effects against UTI. However, proanthocyanidins are poorly absorbed in the small intestine, but subjected to extensive biotransformation in the colon, although studies are almost restricted to B-type proanthocyanidins. Therefore, the hypothesis of this study is that urinary metabolome from of A-type and B-type proanthocyanidins-mainly derived from their colonic catabolism-differ,and only metabolites from the A-type procyanidins have protective effects against UTI. To test this hypothesis, JAXc3H/OuJ female mice previously fed with specific diet (control, 1% cranberry extract and 1% grape seed extract) for 2 weeks, were inoculated with the uropathogenic E. coli (ATCC 53503™) to provoke infection, and maintained 2 weeks more before being sacrificed. Urine samples were collected at different times and subjected to E.coli counting, leukocytary esterase and nitrites analyses, and mieloperoxidase task. Samples of kidney and bladder tissues were also collected for E. coli counting and histopathologic analysis. Additionally, the capacity of the urine samples to inhibit bacterial adherence was tested in the T24 bladder cell line (ATCC HTB4 ™).