Urine Proteomic Study in OAB Patients-Preliminary Report

Abstract

Overactive bladder (OAB) is defined by International Urogynecological Association (IUGA)/ International Continence Society (ICS) as urinary urgency, usually accompanied by frequency and nocturia, with or without urgency urinary incontinence, in the absence of urinary tract infection (UTI) or other obvious pathology. The pathophysiology of OAB is not well understood, however a number of different proteins and cytokines including vascular cell adhesion molecule-1 (VCAM-1) were found to be important in regulating structural integrity of the bladder wall. Proteome analysis may thus provide significant information with regard to OAB and may help in discovering novel diagnostic disease biomarkers. Sixteen Caucasian women aged 32-78 were included in the study. Patients were placed within 2 groups: OAB group (n = 8) and control group (n = 8). Urine samples were collected, immediately preserved in a protease inhibitor mixture, and frozen at -80 ℃. All samples were then further processed according to the isobaric tags for relative and absolute quantification (iTRAQ) manual. Proteins were labeled and analyzed in the mass spectrometer conjugated with liquid chromatograph (data are available via ProteomeXchange with the identifier PXD017799). There were no statistically significant differences in demographic data between control and OAB groups. VCAM-1 was the only protein that reached statistical significance as a differentiating protein in both of our experiments assessing the proteomic constitution in OAB patients. Studies involving a larger group of patients may provide further information on urinary bladder proteomics.

Keywords: lower urinary tract symptoms; overactive bladder; proteomics; urgency urinary incontinence; vascular cell adhesion molecule-1.

Figure 1

Results of qualitative analysis—a Venn diagram representing the number of proteins identified by two or more peptides in two biological replicates of the iTRAQ experiment. Here, 953 proteins are common to both experiments. iTRAQ, isobaric tags for relative and absolute quantification.