Morphological features of biological and tissue-engineered vascular patches remodeling: results of tests on a sheep model

Abstract

One of the ways to reconstruct the arterial wall is endarterectomy with a vascular patch. The use of vascular wall prostheses made from existing materials can lead to complications with the need for reoperation. The search for new materials for the manufacture of vascular patches that have optimal compatibility with the vessel wall is still relevant.Aim: To study the dynamics and compare the morphological features of remodeling of tissue-engineered vascular patches from silk fibroin (SF) and biological xenopericardium (XP) flaps implanted into the wall of the sheep carotid artery.Material and Methods. Matrices from a 15% SF solution (n = 2) were prepared by electrospinning. For comparison, bovine pericardial flaps were used (n = 2). Vascular patches were implanted into the wall of the carotid artery in sheep for 2 and 6 months. A histological examination of explanted samples of vascular patches, scanning electron microscopy and confocal microscopy with specific immunofluorescent staining of the preparations were performed.Results. Based on the implanted SF-patch, neointima and neoadventitia were formed. After 2 months of implantation, the SFmatrix retained its structure; after 6 months, there were signs of moderate biodegradation of the material with the replacement of the vessel wall with its own tissue. There were no areas of calcification or massive inflammation. After 6 months, neointimal hyperplasia was detected in the projection of the implanted SF-patch. Based on the implanted XP-flap, neointima and neoadventitia were also formed. After 2 months, delamination of the implanted XP was revealed. After 6 months, neointimal hyperplasia was found in the projection of the XP-patch.Conclusion. Remodeling of the SF-patches and XP-flaps implanted into the wall of the sheep carotid artery followed the formation of a three-layer structure resembling the architecture of the vessel’s own wall, with signs of moderate biodegradation of the material. Neointimal hyperplasia is explained by insufficient compliance of the arterial wall and the patch and requires improvement in the composition of the implanted matrix.