BERKELEY, CA (UroToday.com) - It is widely accepted that the apical surface of mammalian urothelium is covered by numerous rigid-appearing plaques that contribute to the specialized permeability barrier. These plaques contain 4 major integral membrane proteins: uroplakin 1a, uroplakin 1b, uroplakin II, and uroplakin III. Animal knockout models without uroplakin II or III have a greatly decreased number and average size of apical plaques and develop vesicoureteral reflux and hydronephrosis.

Zeng and colleagues from Japan and the University of Pittsburgh quantitatively measured gene expression of uroplakin in bladder biopsy samples from 29 patients with interstitial cystitis as defined by NIDDK criteria (that is with glomerulations or ulceration on endoscopy under anesthesia) and 16 control subjects using real-time reverse transcriptase-polymerase chain reaction. While messenger RNA levels of the uroplakin Ia, Ib, and II genes were relatively low and uroplakin III was relatively high in interstitial cystitis bladders compared to controls, uroplakin III-delta4, a splicing variant of uroplakin III, was significantly up-regulated in non ulcerative interstitial cystitis samples.

The authors conclude that uroplakin III-delta4 may be a potential marker for the difficult to diagnose patient with nonulcerative interstitial cystitis. Their finding is also provocative in terms that it represents a possible autoimmune response associated with the urinary tract. The findings are also consistent with the theory that interstitial cystitis is actually at least 2 distinct disorders, an ulcerative and nonulcerative disorder, with 2 distinct pathogeneses. It would be interesting to test a group of BPS/IC patients for both antiproliferative activity and uroplakin III-delta 4 and compare findings in a group of patients without glomerulations on examination.

Zeng Y, Wu XX, Homma Y, Yoshimura N, Iwaki H, Kageyama S, Yoshiki T, Kakehi Y

J Urol. 178(4):1322-1327, October 2007
doi:10.1016/j.juro.2007.05.125

PubMed Abstract
PMID: 17698128

UroToday.com Painful Bladder Syndrome Section

Written by Philip M. Hanno, MD, a Contributing Editor with UroToday.

Please log-in or register in order to submit comments.

Powered by AkoComment!