ABSTRACT
Objective · To develop a new hybrid tissue-engineered vascular graft (HTEV) with excellent mechanical properties and biological functions. Methods · Decellularized rat aortas (DRAs) were prepared. Then, electrospinning nano poly (1,3-diamino-2-hydroxypropane-co-polyolsebacate) (ES-APS) was used to sheathe DRAs in order to improve the mechanical properties. After that, the intima of HTEV scaffold was modified with heparin coating. HTEVs were implanted in rat models in vivo to evaluate their biological functions. Six weeks later, vascular ultrasound and micro-CT angiography were carried out. Results · The donor aortic vessels were successfully decellularized. The total DNA content of DRA group [(115.4±10.9) ng/mg] significantly decreased compared with natural aorta group [(398.6±14.6) ng/mg] (P=0.000). But collagenous fibers and elastic fibers of decellularized vessels were severely injured. Mechanical tests of scaffolds showed that ES-APS significantly enhanced the mechanical properties. The wall thickness [(187±11) μm], suture retention strength [(0.51±0.06) N] and burst pressure [(2103±232) mmHg] of HTEV group all significantly increased compared with DRA group (P<0.01). Heparin coating modification of HTEV significantly reduced the number of adhesive platelets. Vascular ultrasound and micro-CT angiography showed all grafts were totally patent 6 weeks after implantation in rat models. ES-APS sheath successfully prevented the occurrence of vasodilation and aneurysm formation. Conclusion · DRA sheathed with ES-APS on adventitia and coated with heparin on intima is a new kind of HTEV, which possesses increased tensile strength and improved biocompatibility.
ABSTRACT
PURPOSE: The objective of this study is to develop a tissue-engineered vascular graft using autologous bone marrow-derived cells (BMCs) and allogenous acellular vascular graft. METHOD: We developed a tissue- engineered vascular patch using autologous BMCs and allogenous acellularized tissue patches. The patches were implanted into the inferior vena cava of a canine in vivo model. Three weeks after implantation, the retrieved patches were investigated by histological and immunohistochemical analyses. RESULT: Cultured BMCs differentiated into endothelium-like and smooth muscle-like cells. The patch graft maintained patent for 3 weeks without any signs of thrombus formation. Histological, immunohistochemical, and scanning electron microscopic analyses of the retrieved patches revealed that new vascular tissues were successfully reconstructed within the patch matrices. CONCLUSION: The tissue-engineered vascular patch using autogenous BMCs and allogenous acellularized matrix maintained patent for 3 weeks and showed vascular tissues generation similar to native blood vessel. The findings of no thrombus and no aneurysmal formation in patch indicated good antithrombogenic property and mechanical property. This study demonstrates the feasibility of utilizing BMCs as an alternative cell source to reconstruct vascular tissues.
Subject(s)
Aneurysm , Blood Vessel Prosthesis , Blood Vessels , Bone Marrow Cells , Bone Marrow , Thrombosis , Tissue Engineering , Transplants , Vena Cava, InferiorABSTRACT
PURPOSE: The objective of this study is to develop a tissue-engineered vascular graft using autologous bone marrow-derived cells (BMCs) and biodegradable polymer scaffold. METHOD: Autologous canine BMCs were isolated from bone marrow aspirate and cultured. A tubular scaffold was fabricated by immersing polyglycolic acid (PGA) sheet in poly (glycolide-co-caprolactone) (PGCL) solution and wrapping it around a cylindrical mold. The expanded BMCs were seeded onto the PGA/PGCL tubular scaffold (internal diameter: 7 mm, length: 35 mm) and further cultured in vitro for 1 week. The graft was anastomosed to the abdominal artery in a canine model. One week after implantation, the retrieved graft was investigated by histological and immunohistochemical analyses. RESULT: Cultured BMCs differentiated into endothelial-like and smooth muscle-like cells. The PGA tubular scaffold reinforced with PGCL was successfully implanted in an animal model without graft rupture. The vascular graft engineered with BMCs was occluded at 1 week after implantation due to thrombus formation. Histological and immunohistochemical analyses of the retrieved graft revealed that extracellular matrix proteins such as smooth muscle alpha-actin, smooth muscle myosin heavy chain and collagen were produced partially in the graft media. CoNCLUSION: The tissue-engineered vascular graft developed in this study led to graft failure due to early occlusion. Nevertheless, it is confirmed that the PGA/PGCL scaffold has microstructures appropriate for cell proliferation and good mechanical properties. This result suggests the possibile application of this scaffold as a material for engineering of diseased vascular tissues.