Urinary Sphingosine-1-Phosphate as a Biomarker for Bladder Pain Syndrome.

Abstract

Sphingosine-1-phosphate (S1P) is a signaling molecule involved in inflammation and bladder contraction. The aims of this case-control pilot study were to compare urinary S1P concentrations in bladder pain syndrome (BPS) participants to controls and determine whether these concentrations correlate with disease severity and duration. Adult females with BPS and controls were enrolled. Bladder pain syndrome participants completed an O'Leary-Sant questionnaire. Information on duration of symptoms and treatment history was obtained. Urinary S1P and creatinine concentrations were determined. Mann-Whitney U tests were used to compare groups, and Spearman correlation was used to test for associations between concentrations and duration and severity of symptoms. Twenty-five participants were in each group. Median S1P concentration was 1,225 ng/dL in the BPS group and 2,183 ng/dL in the control group, which was significantly different (P < 0.0001). This difference did not persist when normalized to urinary creatinine (P = 0.58). No differences were noted in urinary S1P concentrations between treated and untreated participants (P = 0.53) or with symptom scores of 13 or greater and less than 13 (P = 0.69). Sphingosine-1-phosphate levels did not correlate with O'Leary-Sant scores (P = 0.08) or duration of symptoms (P = 0.67). Results did not change when using S1P concentrations normalized to creatinine. This study demonstrated successful quantification of human urinary S1P concentrations. A difference in urinary S1P was found between BPS participants and controls but not when normalized to creatinine. While this is the first study to investigate urinary S1P as a biomarker for BPS, results suggest that it may have a potential role as a biomarker requiring further research.