Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
Horm Metab Res. 2012 Jul;44(8):625-31. doi: 10.1055/s-0032-1309056. Epub 2012 Apr 19.
The steroid hormone dehydroepiandrosterone (DHEA), suggested to be a cardioprotector, prevents platelet aggregation in healthy humans. This hormone is reduced in postmenopausal women by 60% of its normal value. Platelets in patients with type 2 diabetes (T2D) are more sensitive to aggregation, which has been attributed to a reduced ability to produce nitric oxide (NO). In light of these precedents and considering that DHEA is able to increase the production of NO in cultured endothelial cells, we suggest that DHEA prevents the aggregation of platelet from postmenopausal women with T2D through the activation of PKC/eNOS/NO/cGMP pathway. To determine the effect of DHEA in platelet aggregation, platelet-rich plasma (PRP) obtained from postmenopausal women with T2D was preincubated with DHEA, and aggregation induced by ADP was determined in the presence or absence of L-NNA (LNG-nitroarginine), Rottlerin, NOS, or PKC delta inhibitors, respectively. Platelet NO production was measured with the fluorescent probe DAF2DA and eNOS activation was determined by Western blot, using an anti-p-eNOS (ser 1177) antibody. DHEA 1) prevented platelet aggregation by 40% compared to control, 2) increased NO production by 63%, 3) increased p-eNOS (phosphorylated endothelial nitric oxide synthase) levels, and 4) increased cGMP production. These effects were reduced in the presence of L-NNA or Rottlerin. DHEA prevents platelet aggregation induced by ADP. This effect is mediated by the activation of the PKCδ/eNOS/NO/cGMP pathway. Our results suggest that DHEA could be considered to be a potential therapeutic tool in the prevention of atherothrombotic processes in postmenopausal women with T2D.
甾体激素脱氢表雄酮(DHEA)被认为是一种心脏保护剂,可防止健康人群的血小板聚集。这种激素在绝经后妇女中的含量降低到正常值的 60%。2 型糖尿病(T2D)患者的血小板对聚集更敏感,这归因于其产生一氧化氮(NO)的能力降低。鉴于这些先例,并考虑到 DHEA 能够增加培养的内皮细胞中 NO 的产生,我们建议 DHEA 通过激活 PKC/eNOS/NO/cGMP 途径来防止 T2D 绝经后妇女血小板的聚集。为了确定 DHEA 对血小板聚集的影响,用 DHEA 预先孵育从 T2D 绝经后妇女获得的富含血小板的血浆(PRP),并在存在或不存在 L-NNA(LNG-硝基精氨酸)、Rottlerin、NOS 或 PKC delta 抑制剂的情况下,分别测定由 ADP 诱导的血小板聚集。使用荧光探针 DAF2DA 测量血小板 NO 产生,并用抗 p-eNOS(丝氨酸 1177)抗体通过 Western blot 测定 eNOS 激活。DHEA 1)与对照组相比,可使血小板聚集减少 40%,2)使 NO 产生增加 63%,3)增加 p-eNOS(磷酸化内皮型一氧化氮合酶)水平,4)增加 cGMP 产生。在存在 L-NNA 或 Rottlerin 的情况下,这些作用会降低。DHEA 可防止 ADP 诱导的血小板聚集。这种作用是通过激活 PKCδ/eNOS/NO/cGMP 途径介导的。我们的结果表明,DHEA 可被视为预防 T2D 绝经后妇女动脉血栓形成过程的潜在治疗工具。