In vivo recellularization of xenogeneic vascular grafts decellularized with high hydrostatic pressure method in a porcine carotid arterial interpose model

Abstract

Autologous vascular grafts are widely used in revascularization surgeries for small caliber targets. However, the availability of autologous conduits might be limited due to prior surgeries or the quality of vessels. Xenogeneic decellularized vascular grafts from animals potentially substitute for autologous vascular grafts. Decellularization with high hydrostatic pressure (HHP) is reported to highly preserve extracellular matrix (ECM) which would be feasible for recellularization and vascular remodeling after implantation.In the present study, we conducted xenogeneic implantation of HHP-decellularized bovine vascular grafts from dorsalis pedis arteries to porcine carotid arteries then evaluated graft patency, ECM preservation and recellularization. Surgical procedure not to damage luminal surface of the grafts from drying significantly increased the graft patency at 4 weeks after implantation (P = 0.0079). After the technical improvement, all grafts (N = 5) were patent with mild stenosis due to intimal hyperplasia at 4 weeks after implantation. Neither aneurysmal change nor massive thrombosis was observed even without administration of anticoagulants nor anti-platelet agents. Elastica van Gieson and Sirius-red stainings revealed fair preservation of ECM proteins including elastin and collagen after implantation. Luminal surface of grafts was thoroughly covered with von Willebrand factor-positive endothelium. Scanning electron microscopy on luminal surface of implanted grafts exhibited cobblestone-like endothelial cell layer which is similar to native vascular endothelium. Recellularization of tunica media with alphasmooth muscle actin-positive smooth muscle cells was partly observed. Thus, we confirmed that HHP-decellularized grafts are feasible for xenogeneic implantation accompanied by recellularization by recipient cells. (243 words)

Effect of luminal surface structure of decellularized aorta on thrombus formation and cell behavior

“…Based on this result, it was suggested that drying out the luminal surface of the decellularized aorta may lead to neointima hyperplasia. This in vitro result correlates with a previous in vivo study that showed vessel occlusion when the intima were dried before implantation [ 23 ]. As for the HHP tunica media, initial adhesion of HUVECs was observed, but they were shed during cell culturing.…”

“…The results showed that the anti-coagulability was higher for HHP-treated tunica-intima and lower for decellularized aortas with disordered luminal surface structures (HHP 90°C tunica-intima, HHP 30 min dried tunica-intima, HHP tunica-media). Previously, it was reported that damaging the luminal surface of grafts by drying decreased graft patency after transplantation [ 23 ]. Therefore, this in vitro result correlates with the in vivo results and indicates that the more similar the luminal surface structure is to the native aorta, the higher the anti-coagulant property.…”

A novel approach for the endothelialization of xenogeneic decellularized vascular tissues by human cells utilizing surface modification and dynamic culture

“…To maintain the extracellular matrices (ECMs) after decellularization with a sufficient efficiency of decellularization and microorganism removal, we developed an original physical decellularization method called a high hydrostatic pressure (HHP) method [12][13][14] . We recently confirmed that implantation of xenogeneic HHP-decellularized vascular tissue in a large animal model could confer endothelial cell migration and maintenance of endothelium in the implanted vascular tissue 15 . However, thromboembolism occurred after implantation when the inner surface of the vascular grafts was damaged by dry conditions during surgery, possibly owing to the absence of an intact endothelial cell layer before implantation; this encouraged us to address this problem for the broader application of this technology.…”

A novel approach for the endothelialization of xenogeneic decellularized vascular tissues by human cells utilizing surface modification and dynamic culture

“…To maintain the extracellular matrices (ECMs) after decellularization with a su cient e ciency of decellularization and microorganism removal, we developed an original physical decellularization method called a high hydrostatic pressure (HHP) method [12][13][14] . We recently con rmed that implantation of xenogeneic HHP-decellularized vascular tissue in a large animal model could confer endothelial cell migration and maintenance of endothelium in the implanted vascular tissue 15 . However, thromboembolism occurred after implantation when the inner surface of the vascular grafts was damaged by dry conditions during surgery, possibly owing to the absence of an intact endothelial cell layer before implantation; this encouraged us to address this problem for the broader application of this technology.…”