Cell-seeded Acellular Artery For Reconstruction Of Long Urethral Defects In A Canine Model

Background: The urethra is part of the lower urinary tract and its main role is urine voiding.Its complex histological structure makes urethral tissue prone to various injuries with complicated healing processes that often lead to scar formation.Treatment of urethral stricture is more difficult,and the stenosis is easy to recur after surgery.The most commonly used clinically is the oral mucosa to replace the urethra,or free skin transplantation to replace the urethra.However,oral mucosa and other tissues are often taken from a limited number,and there is a certain complication rate in the area of the material.Objective: We explored the feasibility of reconstructing a relatively long segment of urethra by the cell-seeded acellular artery in a canine preclinical model.Materials and Methods: The acellular arterial matrix was obtained from the excised carotid artery of male donor dogs that were not included in the study.Autologous adipose-derived stem cells(ADSCs)from 6 male dogs were grown and seeded onto a pre-configured acellular arterial matrix(3 cm in length).Long urethral segment was resected in 12 male dogs.Urethroplasty was performed with acellular arterial matrix seeded with ADSCs in 6 animals and without cells in 6.Serial urethrography was performed at 1 and 3 months postoperatively.The animals were sacrificed for analysis at predetermined time points(three animals in each group at 1 month and 3 months respectively).Results: Retrograde urethral angiography showed wide-caliber urethras without strictures in animals implanted with cell-seeded matrices.The urethral segments replaced with acellular scaffolds collapsed.Gross examination of the urethral implants seeded with cells showed normal-appearing tissue without evidence of fibrosis.Histologically,an epithelial cell layer surrounded by muscle fiber bundles was observed on the cell-seeded constructs,and cellular organization increased over time.The epithelial and smooth muscle phenotypes were confirmed using antibodies to pancytokeratins AE1/AE3 and ?-smooth muscle actin.CD34 staining to detect progressive urethral neovascularization.Conclusions: This study provides preclinical evidence that ADSCs-seeded arterial matrix can be used as tubularized scaffold in the reconstruction of 3-cm-long urethral defect in male canine model.ADSCs-seeded arterial matrix remodels and regenerates normal-appearing urethral tissue layers over time.