ABSTRACT
Cardiovascular diseases such as atherosclerosis remain the leading cause of morbidity and mortality in the world. The replacement of large diameter vessels (≥6 mm), such as the aorta, has been performed successfully with synthetic non-degradable vascular grafts, while it is still a challenge to engineer small diameter vessels with long-term patency. Over the past three decades, the rapid progress in the field of vascular tissue engineering has provided some promising approaches, including in vitro, in vivo, and in situ tissue engineering of vascular grafts. This review is focused on the most recent progress and trends in vascular tissue engineering.
ABSTRACT
BACKGROUND:Polyvinyl alcohol is a biocompatible and biodegradable polymer. It is widely used in clinical areas because of its water-soluble, film forming, emulsification, adhesiveness, tasteless, and nontoxic. OBJECTIVE:To review the applications of polyvinyl alcohol and its composite materials in bone, cartilage, skin, vessels and other tissue engineering scaffolds. METHODS:A computer-based online search of CNKI database from January 2000 to December 2011, PubMed database and Elsevier (ScienceDirect) database from January 1980 to December 2012, was performed by the first author with key words of“poly(vinyl alcohol), composite material, tissue engineering scaffold”both in Chinese and English. Literatures concerning polyvinyl alcohol and its composite materials in bone, cartilage, skin, vessels and other tissue engineering scaffolds were included, and repetitive research was excluded. RESULTS AND CONCLUSION:Although there are not enough strength, complications and other shortcomings in vivo, due to its good biocompatibility and biodegradable properties, polyvinyl alcohol and its composite materials have made great progress in tissue engineering applications from the laboratory to the pre-clinical research. But its long-term effects need further research. It wil be a main research aim of scaffold materials in the future to improve the interaction of cel s with the scaffold materials by surface modification, to prepare biomimetic materials by cel microenvironment simulation, to improve the hydrophilicity, the adhesion of cel s, and cel differentiation and proliferation, to bionic the structure and function of the natural extracel ular matrix by building three-dimensional porous structure and control ing the release of cel growth factors, to meet the need of tissue regeneration by congruity or harmony of degradation and mechanical strength.
ABSTRACT
BACKGROUND:Due to the much higher requirement of biocompatibility and anticoagulant of smal-diameter vascular grafts than those of large-diameter ones, in situ blood vessel regeneration occurs as a new research direction. OBJECTIVE:To summarize the recent research development of electrospun smal-diameter scaffolds and to explore the application of in situ blood vessel regeneration and the development tendency. METHODS:The first author retrieved China National Knowledge Infrastructure database, Wanfang data and ISI Web of Knowledge foreign database to retrieve literatures addressing the fabrication of electrospun smal-diameter nanofibrous vascular grafts, surface modification and mimicking extracel ular matrix, as wel as the evaluation of biocompatibility and security after grafting. RESULTS AND CONCLUSION:Electrospun smal-diameter nanofibrous vascular grafts have emerged as promising candidates in vascular tissue engineering. By using both natural and synthetic polymers, the scaffolds can achieve a good balance between mechanical property and biocompatibility. Meanwhile, the fabrication of multi-layered vascular scaffolds, functional surface modification and mimicking extracel ular matrix structural y and functional y are now becoming attractive research directions. However, at current stage, electrospun vascular scaffolds used clinical y are basical y formed by synthetic materials, which have limited biocompatibility and anticoagulant activity. In this case, more efforts should be paid to find an optimal ratio between natural and synthetic materials for the improvement of biocompatibility and anticoagulant ability of smal-diameter vascular grafts.
ABSTRACT
Endothelial progenitor cells (EPCs) can differentiate into mature endothelial cells and participate in postnatal vascular regeneration and impaired endothelium repair.Rearches in recent years on use of EPCs as seed cells in promoting angiogenesis,maintaining the integrity of endothelial function and constructing tissue engineered blood vessels are reviewed.