Fukuda K, Ozaki Y, Satoh K, Kume S, Tawata M, Onaya T, Sakurada K, Seto M, Sasaki Y
Frontier 21 Project, Life Science Center, Asahi Chemical, Tagata, Shizuoka, Japan.
Diabetes. 1997 Mar;46(3):488-93. doi: 10.2337/diab.46.3.488.
Platelet function in patients with NIDDM is enhanced. We have found that spontaneous aggregation (i.e., the formation of small-sized aggregates in the absence of agonist stimulation) occurs at a high rate in platelets from NIDDM patients. We then investigated basal myosin light chain 20 (MLC) phosphorylation, which plays a key role in platelet shape change and aggregation, using a monoclonal antibody against a phosphorylation site (serine 19 residue) in the MLC molecule in platelets from these patients. Standard calibration curves obtained from purified MLC or the phosphorylated form of myosin light chain 20 (MLC-P) were linear within the range of 0-150 ng for MLC and 0-3 ng for MLC-P. The amount of MLC or MLC-P in platelets was estimated, and basal MLC phosphorylation was calculated. Platelets were obtained from 9 young healthy control subjects, 13 age- and sex-matched nondiabetic control subjects, and 13 patients with NIDDM. The basal MLC phosphorylation in platelets was significantly higher in the NIDDM patients than in the control subjects, irrespective of age. These findings suggest that platelets from NIDDM patients are activated in vivo. Platelets obtained from NIDDM patients generated spontaneous aggregation, the degree of which was significantly higher than that in control subjects. Platelet spontaneous aggregation correlated well with basal MLC phosphorylation. These findings suggest that increases in basal MLC in platelets may be one factor leading to hyperaggregability of platelets in these patients.
非胰岛素依赖型糖尿病（NIDDM）患者的血小板功能增强。我们发现，NIDDM患者的血小板中自发聚集（即在无激动剂刺激的情况下形成小尺寸聚集体）发生率很高。然后，我们使用针对这些患者血小板中肌球蛋白轻链20（MLC）分子磷酸化位点（丝氨酸19残基）的单克隆抗体，研究了基础MLC磷酸化，其在血小板形状变化和聚集中起关键作用。从纯化的MLC或磷酸化形式的肌球蛋白轻链20（MLC-P）获得的标准校准曲线在MLC为0 - 150 ng和MLC-P为0 - 3 ng的范围内呈线性。估计血小板中MLC或MLC-P的量，并计算基础MLC磷酸化。从9名年轻健康对照受试者、13名年龄和性别匹配的非糖尿病对照受试者以及13名NIDDM患者中获取血小板。无论年龄如何，NIDDM患者血小板中的基础MLC磷酸化均显著高于对照受试者。这些发现表明，NIDDM患者的血小板在体内被激活。从NIDDM患者获得的血小板产生自发聚集，其程度显著高于对照受试者。血小板自发聚集与基础MLC磷酸化密切相关。这些发现表明，血小板中基础MLC的增加可能是导致这些患者血小板高聚集性的一个因素。
