| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
We previously reported that activated platelets adhered to human brain microvascular endothelial cells (HBEC) under flow in vitro using video enhanced contrast (VEC) microscopy. The purpose of the present study was to examine the effect of Arg-Gly-Asp-Ser (RGDS) peptide which block the binding of von willebrand factor (vWF), fibrinogen, and fibronectin to GPIIb/IIIa and NMC-4 which block the binding of vWF to GPIb on platelet adhesion to HBEC.
Methods : To evaluate platelet adhesion at high magnification, we employed a video-enhanced contrast (VEC) microscopy system. in the control group (N=6): HBEC's were cultured on a coverglass and put in the observation chamber of VEC microscopy. PRP was superfused with an infusion pump at a low shear rate (10/sec) for 30 ruin and washed out. Interaction between platelets and endothelial cells was observed by VEC-DIC microscopy and the number of platelets adhered to endothelial cells was calculated. In the ADP group (N=7); PRP containing ADP (2μM) w
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as superfused on HBEC for 30 min and washed out. In the RGDS group (N=6): PRP containing ADP(2μm) and RGDS peptide (50μg/ml) was superfused on HBEC for 30 min and washed out, in the NMC-4 group (N=6): PRP containing ADP (2μM) and NMC4 (10μg/ml) was superfused for 30 min and washed out.
Results : In the control group, platelet adhesion to HBEC was rarely seen, in the ADP group, platelets adhered to HBEC and microaggregates of platelets were seen. In the RGDS group, platelet adhesion to HBEC was rarely seen. In the NMG4 group, platelets adhered to HBEC and microaggregates of platelets were seen. The average number of platelets adhering acid aggregating to endothelial cells was 0.3 ± 0.7/900μm^2 in the control group, 22.3 ± 10.4/900μm^2 in the ADP group (P<0.01, vs control group), 0.3 ± 0.2/900μm^2 in the RGDS group (p<0.01, vs ADP goup) and 18.0 ± 11.6/900μm^2 in the NMC-4 group.
Conclusion : The present study showed RGDS peptide, but not NMG4, ameliorated platelet adhesion to HBEC at a low-flow state in vitro This suggests that the binding of vWF, fibrinogen, and fibronectin to GPIIb/IIIa plays an important role in platelet adhesion to HBEC. Less
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