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|標題:||Physical stimulation and repair in small diameter vascular grafts
Huang, Tsung Bin
|關鍵字:||超音波;ultrasound;低功率雷射;內皮細胞;人工小血管;骨髓間葉幹細胞;lower power laser;endothelial cell;vascular graft;mescenchymal stem cell||出版社:||化學工程學系||摘要:||
EC dysfunction is a main cause of the severity of cardiovascular disease, a substitute for blood vessel is needed to replace the damaged vessel. However, the low long-term patency of small-diameter vascular grafts has been a challenge to researchers in this area. This limitation is due in large part to lack of endothelization and to the frequency of intima hyperplasia near anastomosis. The purpose of this project is to employ physical stimulation to increase the endothelization and thus to improve the long-term patency of the small-diameter vascular grafts.
Specifically, physical stimulations such as ultrasound and low-power laser will be employed to enhance the tissue repair. First, we want to evaluate the effect of therapeutic ultrasound on endothelial cells. Second, RGD-containing protein (CBD-RGD), as well as ultrasonic stimulation to enhance the seeding of endothelial cells on the luminal surface of polyurethane small-diameter vascular grafts was evaluated. Third, evaluate the effect of ultrasound on the nitride oxide synthase expression in endothelial cells. Fourth, we will go further into the effect of ultrasound combined low-power laser on endothelial cells. Finally, we evaluated the effects of ultrasound on the differentiation of the mesenchymal stem cells.
Based on our results, low-intensity ultrasound could change the morphology, enhanced the NO and Ca2+ release and matrix secretion of endothelial cells and such effects persisted when pre-exposed cells were seeded to another substrate. The cells pre-exposed to ultrasound were more spread on the substrate. The actin stress fibers of ultrasound pre-exposed cells on RGD-modified surfaces were especially intense and well oriented. Ultrasound could probably activate cellular integrins and subsequently allowing RGD to bind them. A much firmer adhesion of ultrasound pre-exposed endothelial cells to the biomaterial surface coated with the RGD-containing protein was demonstrated. Furthermore, polyurethane small diameter vascular grafts seeded with ultrasound pre-exposed endothelial cells showed enhanced cell retention on graft surfaces upon flushing. The bioeffect of ultrasound is associated with eNOS gene upregulation. Laser stimulation enhanced the NO and Ca2+ release from the endothelial cells and influenced the cell morphology and matrix secretion but did not promote cell growth. Finally, chondrocyte differentiation was enhanced in the presence of transforming growth factorβ1(TGF-β1) by ultrasound pre-exposure mesenchymal stem cells. In future, we hope to investigate the differentiation of mesenchymal stem cells into cells with phenotypic and function features of endothelial cells by ultrasound pre-exposure.
|Appears in Collections:||化學工程學系所|
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