Effects of shear stress on late endothelial progenitor cell functions / 医用生物力学

Objective To investigate the effects of shear stress on late endothelial progenitor cells (EPCs) functions in vitro and in vivo. Methods Density gradient centrifugation-isolated rat bone marrow mononuclear cells were cultured in EGM-2MV and induced into EPCs. The 3rd~4th generation of EPCs, namely late EPCs, were treated with shear stress (1.2 Pa). Then cell biological functions, such as proliferation, adhesion, migration and ability of tube formation, were assayed with EdU incorporation assay, adhesion testing, Boyden chamber assay and Matrigel, respectively. The gene expression of VEFG was analyzed by real time RT-PCR. The apoptosis and aging situation of late EPCs were assayed by FACS and senescence-associated β-galactosidase (SA-β-gal) staining. The reendothelialization capacity of late EPCs treated by shear stress was evaluated by establishing models of freshly balloon-injured carotid arteries of rats and cell transplantation in situ. Results Shear stress could increase proliferation, adhesion, migration and tube formation of late EPCs (P＜0.05), upregulate the gene expression of VEGF, inhibit EPC apoptosis and delayed EPC aging (P＜0.05). Transplantation of late EPCs treated by shear stress facilitated in vivo reendothelialization in the injured arterial segment and inhibited neointima formation. Conclusions Shear stress within the physiological range can improve the functions of late EPCs and enhance their therapeutic ability of repairing vascular endothelial injury, which provides experimental basis for the clinic application of EPCs and shear stress-mediated cell therapy.

Effects of extracellular matrix on biological characteristics of late endothelial progenitor cells / 生理学报

The present study was designed to investigate the effects of various extracellular matrix (ECM) proteins on the biological characteristics of late endothelial progenitor cells (EPCs). Density gradient centrifugation-isolated rat bone marrow mononuclear cells were cultured in complete M199 medium, which contained 15% fetal calf serum, 10 μg/L vascular endothelial growth factor (VEGF) and 5 μg/L basic fibroblast growth factor (bFGF). EPCs were plated on substrates containing fibronectin (Fn), laminin (Ln) or rat tail tendon collagen (Col), and the corresponding cells were defined as Fn, Ln and Col groups. The 3rd generation EPCs, namely late EPCs, were harvested. The proliferation, adhesion, migration and the ability of forming tubes were assayed using CCK-8, adhesion test, wound healing assay and Matrigel, respectively. The mRNA expressions of endothelial cell differentiation markers, vWF and CD31, were analyzed by real time RT-PCR. The apoptosis was assayed by flow cytometry (FCM). The results showed that cell proliferation ability of Fn and Col groups were higher than that of Ln group; Fn group showed increased adhesion compared to Col and Ln groups (P < 0.01); The migration ability of Fn and Col groups were higher than that of Ln group. Moreover, Fn group showed increased tube formation abilities compared to Col and Ln groups (P < 0.05). Although 24-hour free-serum-induced apoptosis in Ln group was the highest, there was no difference of auto-apoptosis among the three groups. Furthermore, the mRNA expressions of vWF and CD31 exhibited no difference among the three groups. These results suggest the ECM affects the biological functions of late EPCs, which would have a high probability of providing new directions that lead to the development of artificial heart and blood vessels.

Effects of endothelial progenitor cell-conditioned medium on the proliferation, adhesion and migration of vascular smooth muscle cells / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effects of endothelia progenitor cells conditioned medium (EPC-CM) on the migration, adhesion and proliferation of vascular smooth muscle cells (VSMCs).</p><p><b>METHODS</b>Mononuclear cells were isolated from rat bone marrow by density gradient centrifugation,plated on dishes precoated with 5% fibronectin, and then cultured with complete M199 medium (including 15% fetal calf serum, 10 microg/L VEGF and 5 microg/L bFGF). EPC-CM was collected and used to incubate VSMCs isolated from rat arteriae aorta. After 24 h, VSMCs proliferation, adhesion and migration were assayed with CCK-8, adhesion test and modified Boyden chamber assay, respectively.</p><p><b>RESULTS</b>The proliferation, adhesion and migration of VSMCs were obviously decreased when the cells were cultured with EPC-CM.</p><p><b>CONCLUSION</b>EPC-CM could inhibit VSMC functions, which would be one of the mechanisms against atherosclerosis by EPCs.</p>