Development and in vivo validation of tissue-engineered, small-diameter vascular grafts from decellularized aortae of fetal pigs and canine vascular endothelial cells

Journal of Cardiothoracic Surgery, Nov 2017

Tissue engineering has emerged as a promising alternative for small-diameter vascular grafts. The aim of this study was to determine the feasibility of using decellularized aortae of fetal pigs (DAFPs) to construct tissue-engineered, small-diameter vascular grafts and to test the performance and application of DAFPs as vascular tissue-engineered scaffolds in the canine arterial system. DAFPs were prepared by continuous enzymatic digestion. Canine vascular endothelial cells (ECs) were seeded onto DAFPs in vitro and then the vascular grafts were cultured in a custom-designed vascular bioreactor system for 7 days of dynamic culture following 3 days of static culture. The grafts were then transplanted into the common carotid artery of the same seven dogs from which ECs had been derived (two grafts were prepared for each dog with one as a backup; therefore, a total of 14 tissue-engineered blood vessels were prepared). At 1, 3, and 6 months post-transplantation, ultrasonography and contrast-enhanced computed tomography (CT) were used to check the patency of the grafts. Additionally, vascular grafts were sampled for histological and electron microscopic examination. Tissue-engineered, small-diameter vascular grafts can be successfully constructed using DAFPs and canine vascular ECs. Ultrasonographic and CT test results confirmed that implanted vascular grafts displayed good patency with no obvious thrombi. Six months after implantation, the grafts had been remodeled and exhibited a similar structure to normal arteries. Immunohistochemical staining showed that cells had evenly infiltrated the tunica media and were identified as muscular fibroblasts. Scanning electron microscopy showed that the graft possessed a complete cell layer, and the internal cells of the graft were confirmed to be ECs by transmission electron microscopy. Tissue-engineered, small-diameter vascular grafts constructed using DAFPs and canine vascular ECs can be successfully transplanted to replace the canine common carotid artery. This investigation potentially paves the way for solving a problem of considerable clinical need, i.e., the requirement for small-diameter vascular grafts.

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Development and in vivo validation of tissue-engineered, small-diameter vascular grafts from decellularized aortae of fetal pigs and canine vascular endothelial cells

Ma et al. Journal of Cardiothoracic Surgery Development and in vivo validation of tissue-engineered, small-diameter vascular grafts from decellularized aortae of fetal pigs and canine vascular endothelial cells Xu Ma 0 1 Zhijuan He 0 3 Ling Li 2 Guofeng Liu 1 Qingchun Li 1 Daping Yang 1 Yingbo Zhang 1 Ning Li 1 0 Equal contributors 1 Department of Plastic Surgery, The Second Affiliated Hospital of Harbin Medical University , 246 Xuefu Road, Nangang District, Harbin, Heilongjiang 150086 , China 2 Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University , 246 Xuefu Road, Nangang District, Harbin, Heilongjiang 150086 , China 3 Department of Obstetrics and Gynecology, The First Affiliated Hospital of Harbin Medical University , 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150086 , China Background: Tissue engineering has emerged as a promising alternative for small-diameter vascular grafts. The aim of this study was to determine the feasibility of using decellularized aortae of fetal pigs (DAFPs) to construct tissueengineered, small-diameter vascular grafts and to test the performance and application of DAFPs as vascular tissueengineered scaffolds in the canine arterial system. Methods: DAFPs were prepared by continuous enzymatic digestion. Canine vascular endothelial cells (ECs) were seeded onto DAFPs in vitro and then the vascular grafts were cultured in a custom-designed vascular bioreactor system for 7 days of dynamic culture following 3 days of static culture. The grafts were then transplanted into the common carotid artery of the same seven dogs from which ECs had been derived (two grafts were prepared for each dog with one as a backup; therefore, a total of 14 tissue-engineered blood vessels were prepared). At 1, 3, and 6 months post-transplantation, ultrasonography and contrast-enhanced computed tomography (CT) were used to check the patency of the grafts. Additionally, vascular grafts were sampled for histological and electron microscopic examination. Results: Tissue-engineered, small-diameter vascular grafts can be successfully constructed using DAFPs and canine vascular ECs. Ultrasonographic and CT test results confirmed that implanted vascular grafts displayed good patency with no obvious thrombi. Six months after implantation, the grafts had been remodeled and exhibited a similar structure to normal arteries. Immunohistochemical staining showed that cells had evenly infiltrated the tunica media and were identified as muscular fibroblasts. Scanning electron microscopy showed that the graft possessed a complete cell layer, and the internal cells of the graft were confirmed to be ECs by transmission electron microscopy. Conclusions: Tissue-engineered, small-diameter vascular grafts constructed using DAFPs and canine vascular ECs can be successfully transplanted to replace the canine common carotid artery. This investigation potentially paves the way for solving a problem of considerable clinical need, i.e., the requirement for small-diameter vascular grafts. Vascular endothelial cells; Decellularized aortae of fetal pigs; Scaffold; Tissue-engineered small-diameter vascular grafts Background Coronary artery and peripheral arterial diseases have high rates of mortality and morbidity and so represent a massive economic and clinical burden to healthcare worldwide [ 1 ]. The most promising approach to solving this vascular problem and thus reducing the morbidity associated with these diseases is the use of small-diameter (<6 mm) vascular grafts [ 2 ]. Although autologous vessels (e.g., saphenous veins) represent the gold standard grafts for small-diameter vessels, many patients do not have veins suitable for grafting [ 3 ]. Thus, there is a considerable clinical need for small-diameter vascular grafts. Tissue engineering has emerged as a promising alternative for producing small-diameter vascular grafts [ 4 ]. Tissue engineering strategies consist of three main components: scaffolds that house the cells and support cellular growth and activity; seed cells, which preserve the specific function of the tissue; and a nurturing environment [ 5 ]. Scaffolds provide temporary or permanent support to damaged tissues, and scaffold materials can be generally divided into two categories: native biological materials and synthetic polymeric materials [ 6 ]. Compared with synthetic polymer-based scaffolds, natural polymers present a biologically active environment to cells and promote excellent cell adhesion and growth [ 7 ]. However, numerous studies have also reported on the poor mechanical properties of natural polymers [ 7–9 ]. Recently, decellularized tissue-engineered vascular grafts have been widely used as natural scaffolds to produce arterial conduits that provide ideal biomechanical properties and cell compatibility [ 10, 11 ]. For instance, Böer et al. showed that intensified decellularization of equine carotid arteries generated highly suitab (...truncated)


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Xu Ma, Zhijuan He, Ling Li, Guofeng Liu, Qingchun Li, Daping Yang, Yingbo Zhang, Ning Li. Development and in vivo validation of tissue-engineered, small-diameter vascular grafts from decellularized aortae of fetal pigs and canine vascular endothelial cells, Journal of Cardiothoracic Surgery, pp. 101,