Feasibility study of a novel urinary bladder bioreactor.

Area of Science:

• Biomedical Engineering
• Regenerative Medicine
• Urology

Background:

• Simulating physiological conditions ex vivo is crucial for tissue engineering.
• Urinary bladder tissue engineering requires a system that replicates dynamic pressure cycles.
• Existing models may not fully capture the mechanical stresses experienced by bladder tissue.

Purpose of the Study:

• To design and validate a novel bioreactor capable of simulating normal urinary bladder dynamics.
• To assess the suitability of the bioreactor for culturing cells on tissue scaffolds under physiologically relevant mechanical stimulation.
• To evaluate scaffold integrity and cellular activity within the bioreactor environment.

Main Methods:

• A bioreactor was constructed with two chambers to apply controlled hydrostatic pressure to cell-seeded scaffolds (modified porcine acellular matrix).
• Custom software generated linear pressure increases (0-10 cm H2O over 55 min) and rapid decreases (over 10 s) to simulate bladder filling and voiding.
• Small intestinal submucosa scaffolds were tested for mechanical durability, and bladder smooth muscle or urothelial cells were cultured within the bioreactor for 6 hours.

Main Results:

• The bioreactor successfully applied physiologically relevant pressure waveforms for extended periods (up to 18 hours).
• Scaffold integrity was maintained, as confirmed by Masson's trichrome staining.
• Hematoxylin and eosin staining, immunohistochemistry, and RT-PCR confirmed cell presence and continued cellular activity, with cells orienting perpendicular to applied pressure.

Conclusions:

• The developed bioreactor provides a suitable ex vivo model for simulating normal urinary bladder cycling.
• This system supports cell viability and activity on tissue scaffolds under dynamic mechanical loading.
• The bioreactor shows promise for advancing research in bladder tissue engineering and regenerative medicine.