Klinkhardt Ute, Kuczka Karina, Harder Sebastian
Institute for Clinical Pharmacology at the Pharmazentrum Frankfurt, University Hospital, Frankfurt/Main, Theodor Stern Kai 7, D-60590 Frankfurt on the Main, Germany.
Thromb Res. 2003;111(4-5):251-7. doi: 10.1016/j.thromres.2003.09.015.
The sodium-hydrogen exchanger isoform 1 (NHE-1) contributes to platelet activation at elevated pH. Effects of NHE-1 inhibitors on platelet degranulation and formation of proinflammatory and procoagulatory platelet-leukocyte aggregates (PLA) and possible interactions with P2Y(12) inhibitors--which also affect platelet degranulation--have not been investigated. Whole blood from healthy human subjects was incubated with the NHE-1 inhibitor cariporide and the P2Y(12) inhibitor AR-C 69331 MX at clinically reasonable concentrations, in the presence of normal pH or in a propionate model to activate the NHE-1 (approximately pH 7.0). The degranulation marker CD62p, the expression of the activated GPIIb/IIIa receptor (PAC-1), and formation of platelet-leukocyte (monocyte) aggregates (PLA) was assessed by flow cytometry. Cariporide at concentrations up to 20 microg/ml had no effects on ADP- (5 microM) or TRAP- (2 microM) induced CD62p expression or PLA formation at normal pH. At pH 7.0 and stimulation with ADP, PLA decreased from 64+/-24% (control) to 47+/-23% under cariporide at 2 microg/ml (p<0.05), and the MFI of PLA (i.e. the platelet mass attached at monocytes) decreased from 547+/-203 to 360+/-96 units (p<0.05). PAC-1 MFI decreased from 66+/-23 to 34+/-18 units (p<0.05) after ADP and from 74+/-29 to 42+/-17 units (p<0.05) after TRAP, respectively. AR-C 69331 MX (10 nM) had inhibitory effects on all parameters irrespectively of the pH, and the combination of both agents at pH 7.0 shows additive effects. In conclusion, our investigation points to-perhaps clinically relevant-effects of NHE-1 inhibition on the degranulation of platelets and formation of platelet-leukocyte aggregates.
钠氢交换体1型（NHE-1）在pH升高时促进血小板活化。NHE-1抑制剂对血小板脱颗粒、促炎和促凝血血小板-白细胞聚集体（PLA）形成的影响以及与P2Y(12)抑制剂（其也影响血小板脱颗粒）的可能相互作用尚未得到研究。将健康人类受试者的全血与临床合理浓度的NHE-1抑制剂卡立泊来德和P2Y(12)抑制剂AR-C 69331 MX在正常pH条件下或在丙酸盐模型中（以激活NHE-1，约pH 7.0）孵育。通过流式细胞术评估脱颗粒标志物CD62p、活化的糖蛋白IIb/IIIa受体（PAC-1）的表达以及血小板-白细胞（单核细胞）聚集体（PLA）的形成。浓度高达20μg/ml的卡立泊来德在正常pH下对ADP（5μM）或TRAP（2μM）诱导的CD62p表达或PLA形成无影响。在pH 7.0且用ADP刺激时，2μg/ml卡立泊来德作用下PLA从64±24%（对照）降至47±23%（p<0.05），PLA的平均荧光强度（即附着在单核细胞上的血小板质量）从547±203降至360±96单位（p<0.05）。ADP后PAC-1平均荧光强度分别从66±23降至34±18单位（p<0.05），TRAP后从74±29降至42±17单位（p<0.05）。AR-C 69331 MX（10 nM）对所有参数均有抑制作用，与pH无关，且两种药物在pH 7.0时联合使用显示出相加作用。总之，我们的研究指出NHE-1抑制对血小板脱颗粒和血小板-白细胞聚集体形成可能具有临床相关作用。
