title: Mosaic tissue-engineered porcine pulmonary artery valved conduit: long-term follow-up after implantation in an ovine model.
abstract: OBJECTIVE
  To determine the effects of implanting a novel mosaic tissue-engineered porcine pulmonary artery valved conduit into the right ventricular outflow tract of sheep at a long-term follow-up.
  
  
  METHODS
  The designed mosaic tissue-engineered porcine pulmonary artery valved conduits were implanted between the right ventricular outflow tract and distal pulmonary artery in sheep using the off-pump method. The sheep weight, conduit diameter, pulmonary valve annular diameter, left ventricular end-diastolic diameter, calcification and regurgitation of the pulmonary valve were measured preoperatively and at 6 and 12 months postoperatively. Macroscopic observation, ultrastructural analysis, endothelialization and detection of calcium content were performed after sacrificing the sheep at 12 months after surgery.
  
  
  RESULTS
  The average sheep weight at 12 months after surgery was significantly higher than that preoperatively (P <0.05), indicating that the sheep continued to grow well. The transplanted conduit showed unobstructed blood flow, soft walls and a smooth inner wall, but no ectasia or stenosis. The valve of the conduit was partially stiff, able to open and close and mild-to-medium regurgitation was present. The conduit diameter, pulmonary valve annular diameter and the left ventricular end-diastolic diameter were each significantly increased (P <0.05). Haematoxylin-eosin staining and scanning electron microscopy revealed regularly arranged cells with slight inflammatory cell infiltration and a clear, fibrous texture. Immunohistochemical staining indicated that endothelial cell marker CD31-positive cells had formed a continuous film-like structure on the inner wall of the conduit. Scattered smooth muscle actin-positive cells were found in the middle layer of the conduit.
  
  
  CONCLUSIONS
  The mosaic tissue-engineered porcine pulmonary artery valved conduit demonstrated good biocompatibility, did not cause an immune rejection response, contributed to endothelial coverage and has the potential to adapt to the needs of the growth and development of the body.
authors.affiliation: Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China Department of Cardiac Surgery, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Intensive Care Unit, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
authors.forename: Juyi
authors.initials: J
authors.lastname: Wan
authors.affiliation: Department of Cardiac Surgery, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
authors.forename: Da
authors.initials: D
authors.lastname: Gong
authors.affiliation: Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
authors.forename: Qiuxia
authors.initials: Q
authors.lastname: Shi
authors.affiliation: Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
authors.forename: Zifan
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Molecular Biology, Institute of Heart, Lung and Blood Vessel, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
authors.forename: Xiufang
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China 18610081078@163.com.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Li
keywords: Mosaic; Ovine model; Porcine pulmonary artery; Tissue engineering; Valved conduit