Decreased levels of S-100 protein in non-ulcer interstitial cystitis.

Interstitial cystitis (IC) is a chronic debilitating condition which mainly affects women. Accumulated evidence indicates that IC is a heterogeneous syndrome. As compared to classic IC, the non-ulcer type of IC appears to be different concerning symptomatic, endoscopical and histological findings, as well as in response to various forms of treatment. S-100 is a neural protein considered to be located primarily in the axons. To explore further the neurogenic nature of the disease, we compared bladder wall S-100 content in controls and in patients with classic and non-ulcer IC. We noticed a decrease in S-100 content in non-ulcer IC as compared to controls. This may be an expression of altered peripheral innervation in non-ulcer IC, which, in turn, may be an indication of primary neurogenic etiology. The difference in S-100 content between classic and non-ulcer IC supports the hypothesis that they represent separate entities, which may explain differences in response to various treatments.