Effects of shear stress on the number and function of endothelial progenitor cells adhered to specific matrices
The aim of this study was to screen specific adherent matrix for endothelial progenitor cells (EPCs), which can be used for antibody capturing stents.
In this study, the adhesion of EPCs on different matrices containing three different antibodies, VEGFR-2, CD34, CD133, was observed under shear stress in a flow chamber. Nitric oxide (NO) release, cell proliferation and the retention rate of EPCs, were measured separately.
The results demonstrated that shear stress within a certain range can promote proliferation and NO secretion of EPCs. Under the same shear stress, the EPCs showed stronger adhesion on matrix-containing CD133 antibody than on the other matrices.
CD133 antibody has the potential application for EPCs capture.
Available from: Chaojun Tang
- "EPCs are characterized by the expression of CD133, CD34 and the vascular endothelial growth factor receptor-2 (VEGFR2, Flk-1)[13,14]. In previous studies[15,16], several substrates including gelatin , VEGFR2, anti-CD34 or anti-CD133 antibody were investigated in terms of the adherent strength of the EPCs on the stent surface. The results showed that the adherent forces of the EPCs on the stent surface coated with anti-CD133 were higher than those coated with anti- VEGFR2 and anti-CD34. "
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ABSTRACT: It is not clear what effects of CD34- and CD133-specific antibody-coated stents have on re-endothelialization and in-stent restenosis (ISR) at the early phase of vascular injury. This study aims at determining the capabilities of different coatings on stents (e.g. gelatin, anti-CD133 and anti-CD34 antibodies) to promote adhesion and proliferation of endothelial progenitor cells (EPCs). The in vitro study revealed that the adhesion force enabled the EPCs coated on glass slides to withstand flow-induced shear stress, so that allowing for the growth of the cells on the slides for 48 h. The in vivo experiment using a rabbit model in which the coated stents with different substrates were implanted showed that anti-CD34 and anti-CD133 antibody-coated stents markedly reduced the intima area and restenosis than bare mental stents (BMS) and gelatin-coated stents. Compared with the anti-CD34 antibody-coated stents, the time of cells adhesion was longer and earlier present in the anti-CD133 antibody-coated stents and anti-CD133 antibody-coated stents have superiority in re-endothelialization and inhibition of ISR. In conclusion, this study demonstrated that anti-CD133 antibody as a stent coating for capturing EPCs is better than anti-CD34 antibody in promoting endothelialization and reducing ISR.
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ABSTRACT: Endothelial progenitor cells (EPCs) are a unique cell type found circulating in the peripheral blood with the capacity to become mature endothelial cells. EPCs can be released from many sources including the bone marrow, adipose tissue, and the vessel wall. Currently, there are two main methods of isolating EPCs: 1) separation during in vitro cell culture by morphological properties/differences, such as time of outgrowth, or 2) cell sorting with specific markers . There still remains debate with respect to the optimal isolation and culturing procedures; however, there is a consensus regarding the therapeutic potential of EPCs as a cell source for regenerative medicine, including for both replacement and endogenous repair. EPCs can be used as an endothelial cell source for prosthetic vascular grafts. Endogenously, EPCs home to the site of endothelial injury through the following 3 steps: 1) activation where the EPCs are deployed from their resident site as a result of EPC-activation factors, 2) targeting to the area of interest, and 3) exertion of their influence at the desired site. Each of these steps is an area of intense study. Previous studies primarily investigated the behavior of adherent EPCs, but it is unclear how circulating EPCs change in response to their shear environment into a more endothelial phenotype as they home to the site of endothelial injury. Obi et al seek to answer this question in their study in this issue of AJP-Cell . Obi et al. exposed EPCs to a flow environment that had a steady, unidirectional shear (0.25-2.5 dynes/cm2). Obi et al.'s results show that shear primes the EPC to become a mature endothelial cell in transit to its worksite. These results provide insight into how immature, circulating EPCs differentiate in response to flow and could participate in vascular regeneration and repair (both natural and engineered).
Available from: Guixue Wang
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ABSTRACT: Atherosclerosis is an inflammatory disease of large and medium sized arteriole walls that is precipitated by elevated levels of low-density lipoprotein (LDL) cholesterol in the blood. However, the mechanisms that lead to the initiation of atherosclerosis are not fully understood. In this study, endothelial cells (ECs) were incubated with LDL for 24 h, and then the lipid was detected with Oil Red O staining and cholesterol ester was assayed with high-performance liquid chromatography (HPLC). F-actin was examined by fluorescence microscopy and the viscoelasticity of ECs was investigated using the micropipette aspiration technique. Then, a parallel-plate flow chamber device was used to observe the adhesion and retention of ECs under shear stress. The results demonstrated that elevated LDL significantly increased the cellular lipid content and induced the rearrangement of cytoskeletal F-actin. The initial rapid deformability (l/K
1 + l/K
2) was reduced by elevated cellular LDL levels, while membrane viscosity (μ) was increased by LDL accumulation. After treatment with 150 mg L−1 LDL for 24 h, the adhesion of ECs under fluid shear stress was significantly decreased (p < 0.05). These results suggested that LDL induced cellular lipid accumulation and cytoskeleton reorganization which increased the cellular stiffness and decreased the adhesion of ECs.
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