Comparative morphometric study of bladder detrusor between patients with benign prostatic hyperplasia and controls

Area of Science:

• Urology
• Pathology
• Biomedical Engineering

Background:

• Benign prostatic hyperplasia (BPH) is a common condition in aging men.
• BPH can lead to lower urinary tract symptoms due to infravesical obstruction.
• Bladder hypertrophy is a known consequence of chronic obstruction.

Purpose of the Study:

• To investigate the changes in detrusor connective tissue in patients with BPH.
• To correlate connective tissue content with bladder hypertrophy, estimated by ultrasound bladder weight.
• To compare the connective tissue-to-smooth muscle ratio between BPH cases and controls.

Main Methods:

• Autopsy bladder samples from 13 control men and 26 BPH patients undergoing prostatectomy were analyzed.
• Bladder wall tissue sections were stained (Masson trichrome) and analyzed using computer-assisted color imaging.
• The ratio of connective tissue to smooth muscle was quantified and compared with ultrasound-estimated bladder weight in BPH patients.

Main Results:

• The connective tissue-to-smooth muscle ratio was significantly higher in BPH cases (mean 27.3%) compared to controls (mean 24.7%).
• A strong positive correlation (r=0.788) was found between estimated bladder weight and the connective tissue-to-smooth muscle ratio in BPH.
• BPH bladders weighing ≥60 gm showed a significantly increased ratio (>30%), unlike those weighing <60 gm.

Conclusions:

• Abnormal increases in connective tissue, alongside smooth muscle changes, contribute to bladder hypertrophy in BPH.
• This finding highlights the role of fibrosis in the bladder's response to infravesical obstruction.
• The study quantifies the fibrotic component in BPH-induced bladder remodeling.