MP06-08 DETRUSOR PRESSURES ARE ASSOCIATED WITH COLLAGEN TYPE III EXPRESSION IN THE DETRUSOR OF PATIENTS WITH BENIGN PROSTATIC HYPERPLASIA

Abstract

INTRODUCTION AND OBJECTIVE: Studies with patients with benign prostatic hyperplasia (BPH) and animal models of Bladder outlet obstruction (BOO) have shown increased deposition of collagen in the detrusor and increased type III/type I collagen ratio. Collagen deposition in the detrusor has been associated with decreased compliance and detrusor underactivity. The mechanisms involved in the BOO-associated changes in the detrusor extracellular matrix are not well understood. It has been hypothesized that high detrusor pressure promotes increased bladder intramural tension, decreasing blood flow and leading to hypoxia and subsequent fibrosis. We evaluated the gene expression of types I and III collagen (COL I and COL III) in the detrusor of men with BOO due to BPH and its correlation with urodynamic parameters. METHODS: Twenty-eight consecutive patients undergoing open prostatectomy for BPH were evaluated. Urodynamics was performed in all patients preoperatively. A bladder specimen from the dome was obtained during prostatectomy. Nine cadaveric organ donors composed the control group. Detrusor biopsies were prepared for relative gene expression analysis with quantitative real-time polymerase chain reaction of COL I and COL III. Data were expressed as medians and interquartile ranges or absolute values and fractions. Spearman correlation coefficient was used to investigate the association between gene expression and urodynamic parameters, including maximum cystometric capacity (MCC), bladder compliance (BC), maximum flow rate (Qmax), detrusor pressure@maximum flow rate (PdetQmax), bladder outlet obstruction index (BOOI) and bladder contractile index (BCI). RESULTS: Mean age was 67.0 ± 7.4 years and mean prostate volume was 133.8 ± 43.9 cm3. Mean International Prostatic Symptom Score 23.5 ± 6.2. In comparison with controls, patients with BPH had significant overexpression of COL I and COL III, (Table 1). A positive correlation between COL III expression and PdetQmax, BOOI and BCI was found (Table 2). CONCLUSIONS: Gene expression of collagens I and III is increased in the detrusor of men with BPH. We showed a positive correlation between COL III expression and PdetQmax, BOOI and BCI, which is consistent with the hypothesis that high detrusor pressures decrease blood flow to the bladder leading to fibrosis. (Table Presented).