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Author Tefft, Brandon James
Title Enhancement of Endothelial Cell Retention on Vascular Constructs by siRNA-Mediated Gene Silencing
book jacket
Descript 362 p
Note Source: Dissertation Abstracts International, Volume: 72-12, Section: B, page: 7513
Adviser: Shu Q. Liu
Thesis (Ph.D.)--Northwestern University, 2011
Tissue engineered vascular grafts hold great promise as alternative graft sources for vascular bypass surgery. Fulfilling this promise requires a strategy to improve the retention of vascular endothelial cells within the lumen of these grafts upon implantation. Here, a novel gene silencing strategy for increasing endothelial cell adhesion is presented and tested using a custom variable-width parallel plate flow chamber
The protein tyrosine phosphatases SHP-1 and SHP-2 are known to inhibit cell adhesion. By treating human umbilical vein endothelial cells with siRNA specific for SHP-1 or SHP-2 mRNA, it is possible to knockdown the expression of SHP-1 or SHP-2, respectively, and thus enhance endothelial cell adhesion. Endothelial cells that had been untreated, treated with scrambled siRNA, treated with SHP-1 specific siRNA, or treated with SHP-2 specific siRNA were seeded onto fibronectin-coated ePTFE membranes and exposed to a range of pulsatile fluid shear stresses for 1 hour and 6 hours. Fluid shear stress was generated in a custom variable-width parallel plate flow chamber, which was validated both experimentally and computationally. Treatment with SHP-1 or SHP-2 specific siRNA resulted in significantly improved cell retention when compared to the untreated and scrambled siRNA treated controls. For example, after exposure to 6 hours of 15 dyn/cm2 average shear stress, cell retention was significantly higher for SHP-1 siRNA treated cells (72%) and SHP-2 siRNA treated cells (86%) when compared to untreated cells (30%) and scrambled siRNA treated cells (35%)
Furthermore, treatment with SHP-1 or SHP-2 specific siRNA resulted in a 17% increase in focal contact density per cell area compared to untreated and scrambled siRNA treated controls. In addition, neither treatment with SHP-1 specific siRNA nor SHP-2 specific siRNA significantly altered the expression of the endothelial cell markers VE-cadherin, VEGFR-2, and PECAM-1 compared to untreated and siRNA treated controls
This study demonstrates that gene silencing may be an effective strategy for improving the retention of endothelial cells within tissue engineered vascular grafts
School code: 0163
Host Item Dissertation Abstracts International 72-12B
Subject Biology, Molecular
Applied Mechanics
Engineering, Biomedical
Alt Author Northwestern University. Biomedical Engineering
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