Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences, Bengaluru-560029, Karnataka, India.
Department of Neurosurgery, National Institute of Mental Health and Neuro Sciences, Bengaluru-560029, Karnataka, India.
Biol Rev Camb Philos Soc. 2019 Dec;94(6):1897-1917. doi: 10.1111/brv.12541. Epub 2019 Jul 1.
The steroid hormone, oestradiol, has pleiotropic functions. The protective effects of oestradiol are attributed to its anti-inflammatory, antioxidant, anti-atherogenic, anti-apoptotic, vasodilatory activities and regulation of micro RNA. Oestradiol upregulates endothelial nitric oxide synthase gene expression and increases the production of nitric oxide, an important vasodilator. It suppresses the renin-angiotensin system and monitors haemodynamic stress. The hormone maintains the integrity of blood vessels by reducing oxidative stress while upregulating the expression of antioxidant enzymes and prevents vascular inflammation by regulating pro- and anti-inflammatory cytokines. Aneurysmal subarachnoid haemorrhage (aSAH) occurring as a consequence of the rupture of an intracranial aneurysm is a devastating cerebrovascular event, representing 5-7% of all strokes. Postmenopausal women are more susceptible to aSAH compared to men in the same age group. This gender disparity has been attributed to reduced levels of the vascular protective hormone oestradiol following menopause. This review is focused on the protective role of oestradiol on vasculature and how the drop in oestradiol levels after menopause dramatically increases the incidence of aSAH in women. During menopause, oestradiol deficiency may affect vascular integrity causing dysregulation of vascular homeostasis by affecting the renin-angiotensin-aldosterone system (RAAS) and inflammatory and apoptotic cascades, resulting in the weakening of the cerebral arterial wall and potentially to development of an aneurysm and its rupture. In view of the role of oestradiol in maintaining vascular integrity, treatments involving hormone replacement could be a promising approach in postmenopausal women who are at risk of developing or rupturing an intracranial aneurysm.
甾体激素雌二醇具有多种功能。雌二醇的保护作用归因于其抗炎、抗氧化、抗动脉粥样硬化、抗凋亡、血管舒张活性以及对 micro RNA 的调节。雌二醇上调内皮型一氧化氮合酶基因的表达，增加一氧化氮的产生，一氧化氮是一种重要的血管舒张剂。它抑制肾素-血管紧张素系统并监测血液动力学应激。该激素通过减少氧化应激来维持血管完整性，同时上调抗氧化酶的表达，并通过调节促炎和抗炎细胞因子来防止血管炎症。蛛网膜下腔出血（aSAH）是由于颅内动脉瘤破裂而发生的毁灭性脑血管事件，占所有中风的 5-7%。与同年龄组的男性相比，绝经后女性更容易发生 aSAH。这种性别差异归因于绝经后血管保护激素雌二醇水平降低。这篇综述重点介绍了雌二醇对血管的保护作用，以及绝经后雌二醇水平下降如何显著增加女性 aSAH 的发病率。在绝经期间，雌二醇缺乏可能会影响血管完整性，通过影响肾素-血管紧张素-醛固酮系统（RAAS）和炎症及凋亡级联反应，导致脑血管壁减弱，并可能导致动脉瘤的形成和破裂。鉴于雌二醇在维持血管完整性方面的作用，涉及激素替代的治疗方法可能是绝经后有发生或破裂颅内动脉瘤风险的女性的一种有前途的方法。
