title: Differential Expression of Renal Outer Medullary K+Channel and Voltage-gated K+Channel 7.1 in Bladder Urothelium of Patients With Interstitial Cystitis/Painful Bladder Syndrome.
abstract: OBJECTIVE
  To investigate the changes including expression and localization of 2 potassium channels, renal outer medullary K+channel (ROMK) and voltage-gated K+channel 7.1 (KCNQ1), after increased urinary potassium leakage in patients with interstitial cystitis/painful bladder syndrome (IC/PBS).
  
  
  METHODS
  The study group included 24 patients with IC/PBS and a control group consisting of 12 volunteers without any IC/PBS symptoms. Bladder biopsies were taken from both groups. We determined the protein expression and distribution of potassium channels using immunoblotting, immunohistochemistry, and immunofluorescent staining under confocal laser microscopy.
  
  
  RESULTS
  The results revealed that ROMK was predominantly expressed in apical cells of the bladder urothelium at significantly higher levels (3.3-fold) in the study group than in the control group. In contrast, KCNQ1 was expressed in the basolateral membrane according to confocal microscopy results and did not significantly differ between groups.
  
  
  CONCLUSIONS
  Our data showed that the abundance of ROMK protein in apical cells was increased in the IC/PBS group, whereas KCNQ1, which was distributed in the basolateral membrane of the bladder urothelium, showed similar abundance between groups. These results suggest that upregulation of the ROMK channel in apical cells might permit avid potassium flux into the bladder lumen to maintain intracellular K+homeostasis in the dysfunctional urothelium.
authors.affiliation: Department of Urology, Feng-Yuan Hospital, Ministry of Health and Welfare, Taichung, Taiwan, Republic of China; Central Taiwan University of Science and Technology, Taichung, Taiwan, Republic of China; Division of Urology, the Department of Surgery, Taichung Armed Forces General Hospital, Taichung, Taiwan, Republic of China. Electronic address: jane.dar@yahoo.com.tw.
authors.forename: Jane-Dar
authors.initials: JD
authors.lastname: Lee
authors.affiliation: Department of Urology, Feng-Yuan Hospital, Ministry of Health and Welfare, Taichung, Taiwan, Republic of China; Central Taiwan University of Science and Technology, Taichung, Taiwan, Republic of China.
authors.forename: Ming-Huei
authors.initials: MH
authors.lastname: Lee
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, Republic of China; Bachelor Degree Program in Animal Healthcare, Hungkuang University, Taichung, Taiwan, Republic of China.
authors.forename: Wen-Kai
authors.initials: WK
authors.lastname: Yang
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, Republic of China.
authors.forename: Kuan-Lin
authors.initials: KL
authors.lastname: Wang
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, Republic of China.
authors.forename: Tsung-Han
authors.initials: TH
authors.lastname: Lee
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D018856:Cystitis, Interstitial / Q000175:diagnosis / Q000378:metabolism*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007679:Kidney Medulla / Q000378:metabolism* / Q000473:pathology; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D024642:Potassium Channels, Voltage-Gated / Q000096:biosynthesis*; D019459:Urothelium / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D024642:Potassium Channels, Voltage-Gated