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Role of urinary cations in the etiology of interstitial cystitis: A multisite study
Author(s) -
Parsons C Lowell,
Argade Sulabha,
Evans Robert J,
Proctor Jeffrey,
Nickel J Curtis,
Rosenberg Matt T,
Bosch Philip C
Publication year - 2020
Publication title -
international journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 67
eISSN - 1442-2042
pISSN - 0919-8172
DOI - 10.1111/iju.14293
Subject(s) - interstitial cystitis , cationic polymerization , creatinine , urine , chromatography , medicine , high performance liquid chromatography , urinary system , urology , cytotoxicity , chemistry , biochemistry , in vitro , organic chemistry
Objective To determine whether patients with interstitial cystitis have elevated levels of toxic urinary cations, to identify and quantify these cationic metabolites, and to assess their cytotoxicity. Methods Isolation of cationic fraction was achieved by solid phase extraction using an Oasis MCX cartridge on urine specimens from interstitial cystitis patients and controls. C 18 reverse phase high‐performance liquid chromatography was used to profile cationic metabolites, and they were quantified by the area under the peaks and normalized to creatinine. Major cationic fraction peaks were identified by reverse phase high‐performance liquid chromatography and liquid chromatography–mass spectrometry. HTB‐4 urothelial cells were used to determine the cytotoxicity of cationic fraction and of individual metabolites. Results The reverse phase high‐performance liquid chromatography analysis was carried out on cationic fraction metabolites isolated from urine samples of 70 interstitial cystitis patients and 34 controls. The mean for controls versus patients was 3.84 (standard error of the mean 0.20) versus 6.71 (0.37) mAU*min/µg creatinine, respectively ( P = 0.0001). The cationic fraction cytotoxicity normalized to creatinine for controls versus patients in mean percentage was −7.79% (standard error of the mean 3.32%) versus 20.03% (standard error of the mean 2.75%; P < 0.0005). The major toxic cations were 1‐methyladenosine, 1‐methylguanine, N 2 ,N 2 ‐dimethylguanosine and L‐tryptophan. Conclusions These data confirm significant elevation of toxic cations in the urine of interstitial cystitis patients. These toxic cations likely represent a primary cause of interstitial cystitis, as they can injure the bladder mucus and initiate an epithelial leak.