Tumor necrosis factor-α expression in patients with obstructive benign prostatic hyperplasia is associated with a higher incidence of asymptomatic inflammatory prostatitis NIH category IV and prostatic calcification.

OBJECTIVE

The aim of this study was to investigate the association of the expression of tumor necrosis factor-α (TNF-α) with asymptomatic inflammatory prostatitis National Institutes of Health (NIH) category IV and prostatic calculi, in patients with obstructive benign prostatic hyperplasia (BPH) treated by transurethral electroresection of the prostate (TURP).

METHODS

Ninety-six patients with obstructive BPH and TURP were evaluated in a prospective study. Based on a preoperative transrectal ultrasound examination of the prostate gland, patients were divided into two groups, one with prostatic calculi (n = 31) and one without (n = 65). Prostatitis NIH category IV was classified according to Irani's histological grading system (Irani et al. J Urol 1997;157:1301-3). Associations between the incidence of prostatic calculi, histological prostatitis, TNF-α expression, prostate-specific antigen, uric acid, cholesterol, triglycerides, C-reactive protein, International Prostate Symptom Score (IPSS), the International Index for Erectile Function (IIEF-5) and the NIH-Chronic Prostatitis Symptom Index Score (NIH-CPSI) were analyzed.

RESULTS

Prostatitis was confirmed by histological investigation in 71.9% of patients: 83.9% of those with prostatic calculi versus 66.1% of those without (p < 0.04). TNF-α expression was significantly higher in patients with prostatic calculi. Association calculations yielded significant values for the severity (histological grading) of inflammation (p < 0.029), TNF-α expression (p < 0.007), uric acid (p < 0.005), cholesterol (p < 0.028) and the NIH-CPS subdomain of urinary symptoms (p < 0.044) in patients with prostatic calculi.

CONCLUSIONS

In patients with obstructive BPH, prostatic calculi were found on ultrasound in one-third of the cases, and histological NIH category IV prostatitis in two-thirds of cases. The incidence of both prostatitis NIH category IV and TNF-α expression was significantly higher in patients with prostatic calculi than in those without.