Microvascular architecture of the human urinary bladder wall: a corrosion casting study

Area of Science:

• Urology
• Anatomy
• Vascular Biology

Background:

• The urinary bladder wall's vascular system adapts to filling and voiding cycles.
• Few studies detail bladder wall microvasculature, with limited research on the human bladder using outdated methods.
• Understanding bladder vascular architecture is crucial for its functional adaptation.

Purpose of the Study:

• To visualize and describe the microvasculature of the human urinary bladder wall.
• To investigate the vascular architecture's role in accommodating bladder distension.

Main Methods:

• Scanning electron microscopy of vascular corrosion casts from human bladder specimens.
• Specimens were perfused with fixatives and resin, followed by maceration and freeze-drying.
• Analysis focused on tumor-distant regions to assess normal vascular structure.

Main Results:

• The bladder's near-empty state shows mucosal folding and vessel tortuosity.
• An adventitial/serosal plexus supplies capillary networks in the muscularis and mucosa.
• A dense mucosal plexus follows folds, with a highly dense subepithelial capillary network, especially in less folded areas.
• The submucosa is largely avascular, and the muscularis capillary system is poorly developed.

Conclusions:

• The bladder's microvasculature, with its tortuosity and flexibility, efficiently accommodates cyclic stretching and contraction.
• Bladder overdistension may impair blood flow due to urine pressure on vessel patency, not vascular system insufficiency.