Construction of tissue-engineered urine outflow tract using adipose stem cells and expanded polytetrafluoroethylene for canine urinary diversion
Liu Junwei, Yang Sixing, Xiong Yunhe, Song Chao, Liao Wenbiao, Meng Lingchao, Li De, Song Qianlin, He Ziqi, Li Bin
Second Department of Urology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
Abstract: BACKGROUND: Tissue engineering technology was used to construct and form tissue engineering, tubes which can significantly reduce the incidence of various perioperative complications with good anti-urine leakage performance in vitro.
OBJECTIVE: To evaluate the feasibility of using adipose stem cells and expanded polytetrafluoroethylene to construct tissue-engineered urine outflow tract in vitro for canine urinary diversion surgery.
METHODS: In the experimental group, adipose stem cells were isolated and cultured from four female beagles, and then differentiated into urothelial cells in vitro for 14 days. The differentiated cells were implanted on the inner surface of expanded polytetrafluoroethylene tubes to form a tissue-engineered urinary diversion device. Bladders were removed from dogs (only 1.0 cm × 1.0 cm of trigonometric area was retained), and both ends of the tissue engineered urinary diversion device were anastomosed with trigonometric area and abdominal wall respectively to complete the urinary diversion operation. The samples were collected at 1, 2, 4 and 8 weeks postoperatively. The control group (two dogs) underwent urinary diversion with expanded polytetrafluoroethylene engineered tube, and samples were collected 8 weeks after operation. The animal experiment was approved by laboratory animal ethics committee of Renmin Hospital of Wuhan University (approval No. WDRM(Fu)20180810).
RESULTS AND CONCLUSION: (1) There were different degrees of adhesion between the two groups of implanted tissue-engineered urinary diversion devices and the abdominal wall or intestinal wall. Two dogs of the experimental group had mild hydronephrosis, and no serious complications such as urinary exosmosis or infection. One dog in the control group developed severe urinary fistula and died 7 weeks after operation. The tissue-engineered urinary diversion device of the other dog was covered with stones. (2) Hematoxylin-eosin staining showed that thin epithelial cells with loose intercellular connections began to grow continuously in the outflow tract lumen of the experimental group 1 week after operation. At 2 weeks postoperatively, the intercellular connections became dense and the number of epithelial cells increased. Four weeks after operation, the cells began to accumulate and thicken, and gradually changed into a multi-layer structure. The entire lumen was covered by the epidermis, and neovascularization was observed 8 weeks after surgery. (3) The results showed that it was feasible to construct tissue-engineered urine outflow tract together with expanded polytetrafluoroethylene after adipose stem cells were differentiated into urothelial cells for urinary diversion in beagles. The inner cavity of outflow tract could form a tightly connected urothelial cortex with the function of draining urine and preventing urinary extravasation.
Key words: expanded polytetrafluoroethylene, adipose stem cells, urothelial cells, diversion of urine flow, tissue engineering