Urethral Reconstruction Using Oral Keratinocyte Seeded Bladder Acellular Matrix Grafts

Abstract

We investigated the feasibility of urethral reconstruction using oral keratinocyte seeded bladder acellular matrix grafts. Autologous oral keratinocytes were isolated, expanded and seeded onto bladder acellular matrix grafts to obtain a tissue engineered mucosa. The tissue engineered mucosa was assessed using morphology and scanning electron microscopy. In 24 male rabbits a ventral urethral mucosal defect was created. Urethroplasty was performed with autogenic oral keratinocyte seeded bladder acellular matrix grafts in 12 rabbits in the experimental group or with bladder acellular matrix grafts with no cell seeding in 12 in the control group. Retrograde urethrography was performed 1, 2 and 6 months after grafting. The urethral grafts were analyzed grossly and histologically. Oral keratinocytes had good biocompatibility with bladder acellular matrix grafts. Rabbits implanted with oral keratinocyte seeded bladder acellular matrix grafts voided without difficulty. Retrograde urethrography revealed no sign of strictures at 1, 2 and 6 months. In the control group the urethra with repaired defects was accompanied by strictures. Histological examination showed that grafts seeded with oral keratinocytes formed a 1-layer structure by 1 month, and at 2 and 6 months the keratinocytes had formed multiple layers. There was an evident margin between graft oral keratinocytes and host epithelium. The oral keratinocytes at basilar layers of the grafts expressed P63, as shown by immunocytochemistry. In the control group histopathological evaluation revealed that no 1-layer or stratified epithelium cells had developed at the repaired defect sites, whereas an inflammatory reaction was found in 2 rabbits. Oral keratinocytes had good biocompatibility with bladder acellular matrix grafts. Urethral reconstruction with these grafts was better than with bladder acellular matrix grafts alone.