Activation of extrinsic apoptotic pathway from bladder biopsy in patients with interstitial cystitis/painful bladder syndrome.

OBJECTIVE: To investigate the intrinsic or extrinsic pathway of apoptosis from bladder biopsy that was performed in interstitial cystitis/painful bladder syndrome (IC/PBS). Although previous studies have reported observations of the dysfunction, denudation, and thinning of the bladder urothelium in patients associated with an increase of cell apoptosis, the molecular mechanism is unclear.

METHODS: The study group consisted of 32 patients with IC/PBS, and the control group consisted of 12 volunteers without any symptoms of IC. Bladder biopsies were obtained from both the groups. The expression of apoptosis-associated proteins was observed by detecting the Bcl-2/Bax ratio and the levels of cleaved caspase-9, Fas, cleaved caspase-8, and cleaved caspase-3 to differentiate intrinsic or extrinsic pathway. The data were analyzed using Mann-Whitney U test.

RESULTS: Increased levels of cleaved caspase-3 were found in the IC/PBS group relative to the control group (P <.05). The levels of the extrinsic apoptotic pathway proteins, Fas and cleaved caspase-8, were also increased in the study group compared with the control group (P <.05). There was no significant difference in the levels of the intrinsic apoptotic pathway proteins, including cleaved caspase-9 and the Bcl-2/Bax ratio, between the control and study groups.

CONCLUSION: Our findings demonstrate the activation of extrinsic apoptotic pathway from bladder biopsy in patients with IC/PBS. This study might help us to clarify the molecular changes and lead to a better understanding of this bladder disease.