Engineering of Corpus Cavernosum Using Vascular Endothelial Growth Factor-expressing Muscle-derived Stem Cells Seeded on Acellular Corporal Collagen Matrices

Abstract

To explore the feasibility of developing vascularized tissue-engineered corpus cavernosum with vascular endothelial growth factor (VEGF)-expressing muscle-derived stem cells (MDSCs) as seed cells in a rabbit model. MDSCs were isolated and expanded in vitro and transfected with human VEGF(165) lentiviral gene vector. The release of VEGF was confirmed using enzyme-linked immunosorbent assay. Acellular corporal collagen matrices (ACCMs) were obtained from donor rabbit penile tissue using an established decellularization process. Transfected and untransfected MDSCs were seeded on ACCMs. Histochemistry and scanning electron microscopy were performed to analyze the growth and distribution of MDSCs. After constructing animal models, we transplanted the seeded ACCMs to the excised corporal space. The neocorpora was harvested and assayed with Western blot and immunohistochemistry at the first and second month. Enzyme-linked immunosorbent assay indicated that the release of VEGF was significantly increased in the MDSC-VEGF group compared with the other groups. Histochemistry and scanning electron microscopy indicated that VEGF-expressing MDSCs showed better growth and adequate attachment than other groups on the ACCMs in vitro. Immunohistochemical staining showed that the expression of α-smooth muscle actin, von Willebrand factor, and CD31 in the MDSC-VEGF group was markedly increased at different points. The MDSC-VEGF group showed greater improvement on cavernosal contractile function than the other groups. The expression of endothelial nitric oxide synthase in the engineered corporal tissues was significantly greater in the MDSC-VEGF group than in the other groups at different measurement points. As seed cells, VEGF-overexpressing MDSCs could greatly increase the density of capillaries and the content of endothelial smooth muscle cells in constructing the engineered corporal tissues than can untransfected MDSCs.