Preliminary experience with tissue engineering of a venous vascular patch by using bone marrow–derived cells and a hybrid biodegradable polymer scaffold

ObjectiveCurrently available synthetic polymer vascular patches used in cardiovascular surgery have shown serious shortcomings, including thrombosis, calcification, infection, and lack of growth potential. These problems may be avoided by vascular patches tissue-engineered with autologous stem cells and biodegradable polymeric materials. The objective of this study was to develop a tissue-engineered vascular patch by using autologous bone marrow–derived cells (BMCs) and a hybrid biodegradable polymer scaffold.MethodsHybrid biodegradable polymer scaffolds were fabricated from poly(lactide-co-ε-caprolactone) (PLCL) copolymer reinforced with poly(glycolic acid) (PGA) fibers. Canine bone marrow mononuclear cells were induced in vitro to differentiate into vascular smooth muscle cells and endothelial cells. Tissue-engineered vascular patches (15 mm wide × 30 mm long) were fabricated by seeding vascular cells onto PGA/PLCL scaffolds and implanted into the inferior vena cava of bone marrow donor dogs.ResultsCompared with PLCL scaffolds, PGA/PLCL scaffolds exhibited tensile mechanical properties more similar to those of dog inferior vena cava. Eight weeks after implantation of vascular patches tissue-engineered with BMCs and PGA/PLCL scaffolds, the vascular patches remained patent with no sign of thrombosis, stenosis, or dilatation. Histological, immunohistochemical, and scanning electron microscopic analyses of the retrieved vascular patches revealed regeneration of endothelium and smooth muscle, as well as the presence of collagen. Calcium deposition on tissue-engineered vascular patches was not significantly different from that on native blood vessels. Immunofluorescent double staining confirmed that implanted BMCs survived after implantation and contributed to regeneration of endothelium and vascular smooth muscle in the implanted vascular patches.ConclusionsThis study demonstrates that vascular patches can be tissue-engineered with autologous BMCs and hybrid biodegradable polymer scaffolds.

Clinical RelevanceThe purpose of this study was to test the feasibility of engineering a vascular patch with autologous bone marrow–derived cells and a hybrid biodegradable scaffold in a canine model. Eight weeks after implantation, the tissue-engineered vascular patches showed regeneration of vascular tissues with no sign of thrombosis, stenosis, or dilatation. This preliminary study demonstrates that a tissue-engineering strategy using autologous stem cells and a biocompatible, biodegradable polymer scaffold can be applied to repair vascular wall defects.