Taylor M A, Ayers C R, Gear A R
Department of Internal Medicine, University of Virginia, Charlottesville.
Hypertension. 1989 Jun;13(6 Pt 1):558-66. doi: 10.1161/01.hyp.13.6.558.
Abnormal platelet function may contribute to the complications of essential hypertension. We have studied the kinetics of platelet aggregation induced by adenosine diphosphate (ADP) or epinephrine, plasma beta-thromboglobulin, and basal, cytosolic, and free calcium, as correlates of platelet function. Fifteen untreated patients with essential hypertension and without detectable atherosclerosis, 18-40 years old, were compared with 30 matched normotensive control subjects. Maximal rates of platelet aggregation (Vmax) with ADP and epinephrine were significantly higher in patients than in control subjects (p less than 0.03), as assessed by quenched-flow aggregometry. However, significance was lost when Vmax was corrected for the platelet count. Paradoxically, the activation constants (Ka) for ADP were higher in patients than in control subjects (p less than 0.03). With ADP as the inducing agent, onset time (t) or lag period before aggregation begins was longer in patients than in control subjects (p less than 0.02). beta-thromboglobulin levels, an index of in vivo platelet activation, were not significantly different between the two groups (p = 0.13). The mean platelet cytosolic free calcium concentration was higher in patients (213 +/- 19 nM) than in control subjects (172 +/- 14 nM), but this difference was not statistically significant (p = 0.07). However, there was a close correlation between the free calcium level and systolic, diastolic, and mean blood pressure (p less than 0.003, p less than 0.04, p less than 0.004, respectively). No difference in platelet volume between the two groups was found. Our data suggest that platelets in the early stages of essential hypertension display an overall increased aggregation potential but a diminished sensitivity to ADP.(ABSTRACT TRUNCATED AT 250 WORDS)
血小板功能异常可能导致原发性高血压的并发症。我们研究了二磷酸腺苷（ADP）或肾上腺素诱导的血小板聚集动力学、血浆β-血小板球蛋白以及基础钙、胞浆钙和游离钙，作为血小板功能的相关指标。将15名年龄在18 - 40岁、未接受治疗且无明显动脉粥样硬化的原发性高血压患者与30名匹配的血压正常对照者进行比较。通过淬灭流动聚集法评估，患者对ADP和肾上腺素的最大血小板聚集率（Vmax）显著高于对照者（p < 0.03）。然而，当Vmax校正血小板计数后，差异不再显著。矛盾的是，患者对ADP的活化常数（Ka）高于对照者（p < 0.03）。以ADP作为诱导剂时，患者聚集开始前的起始时间（t）或延迟期长于对照者（p < 0.02）。两组间作为体内血小板活化指标的β-血小板球蛋白水平无显著差异（p = 0.13）。患者的平均血小板胞浆游离钙浓度高于对照者（213 ± 19 nM vs 172 ± 14 nM），但差异无统计学意义（p = 0.07）。然而，游离钙水平与收缩压、舒张压及平均血压之间存在密切相关性（分别为p < 0.003、p < 0.04、p < 0.004）。两组间血小板体积无差异。我们的数据表明，原发性高血压早期患者的血小板总体聚集潜能增加，但对ADP的敏感性降低。（摘要截短至250字）
