Biological Mechanisms of Vascular Dysfunction with Age and Estrogen Deficiency

描述（由申请人提供）：本竞争性更新申请（R 01 AG 027678）将扩展和扩展响应RFA-AG-05-008“围绝经期生物学：对健康和衰老的影响”的研究。“第一个奖项期间的发现表明：1）内皮功能（内皮依赖性舒张; EDD）随着卵巢功能的下降而变得更加受损，2）氧化应激是EDD受损的潜在机制之一。该更新申请的全球目标是确定四氢生物蝶呤（BH 4;内皮型一氧化氮合酶（eNOS）和一氧化氮[NO]合成的重要辅因子）和eNOS解偶联作为女性绝经过渡期和衰老时氧化应激相关内皮功能障碍的潜在介质的作用。这将在目标1中使用健康绝经前、绝经后和绝经后女性的横断面比较进行评估。将在基础条件下和BH 4急性增加后测量内皮功能。目的2将通过使用促性腺激素释放激素拮抗剂[GnRHant]在绝经前和围绝经期妇女中短期（10天）抑制雌激素（E2）来扩大横断面比较，以确定E2对EDD的年龄无关性影响。目的3将检查BH 4和抗氧化剂（抗坏血酸; AA）的共同施用用于恢复EDD。主要的假设是，减少EDD在绝经后和绝经后妇女，并在前和围绝经期妇女短期E2抑制后，将增加响应口服BH 4。次要假设预测绝经后和绝经后妇女（基线和E2抑制）EDD降低与血管内皮细胞中BH 4生物合成和氧化应激的血浆和内皮细胞蛋白标志物相关。第三种假设是，共同给予BH 4和AA将使围绝经期和绝经后妇女的EDD恢复到绝经前妇女的水平。为了检验这些假设，将在以下人群中测量肱动脉EDD：1）短期E2抑制（GnRHant）和经皮E2或安慰剂反加治疗前后的绝经前和早期围绝经期女性; 2）基线时的绝经后女性。为了确定内皮功能障碍的可能机制，还将在单独口服BH 4补充后和AA输注期间测量EDD。深入了解EDD减少的分子事件将通过评估参与调节E2缺乏的细胞和系统适应性（包括BH 4生物合成和氧化应激）的蛋白质的内皮细胞表达的变化来确定。[The这项研究的结果将扩展我们早期的发现，并进一步阐明在绝经过渡期介导内皮功能障碍的机制，以及这些过程是否由E2缺乏引发。了解这些机制缺陷将有助于为干预的关键窗口提供信息，并指导未来的性别特异性干预和治疗，以维持血管功能和预防未来的心血管疾病。

DESCRIPTION (provided by applicant): This competing renewal application (R01 AG027678) will extend and expand on research that was responsive to RFA-AG-05-008 "Biology of the Perimenopause: Impact on Health and Aging." Findings from the first award period demonstrate that: 1) endothelial function (endothelium-dependent dilation; EDD) becomes more impaired with declining ovarian function, and 2) oxidative stress is one of the underlying mechanisms involved in impaired EDD. The global aim of this renewal application is to determine the role of tetrahydrobiopterin (BH4; an essential cofactor for endothelial nitric oxide synthase (eNOS) and nitric oxide [NO] synthesis) and eNOS uncoupling as potential mediators of oxidative stress-related endothelial dysfunction with the menopause transition and aging in women. This will be assessed in Aim 1 using cross-sectional comparisons of healthy pre-, peri- and postmenopausal women. Endothelial function will be measured under basal conditions and following an acute increase in BH4. Aim 2 will expand on the cross-sectional comparisons by using short-term (10 days) suppression of estrogen (E2) using gonadotropin releasing hormone antagonist [GnRHant] in pre-and perimenopausal women to determine the age-independent effects of E2 on EDD. Aim 3 will examine the co-administration of BH4 and an anti-oxidant (ascorbic acid; AA) for the restoration of EDD. The primary hypotheses are that the reduced EDD in peri- and postmenopausal women, and in pre- and perimenopausal women following short-term E2 suppression, will increase in response to oral BH4. Secondary hypotheses predict that the reduced EDD in peri- and postmenopausal women (at baseline and with E2 suppression) will be associated with plasma and endothelial cell protein markers of BH4 biosynthesis and oxidative stress in vascular endothelial cells. A tertiary hypothesis is that the co-administration of BH4 an AA will restore EDD in peri-and postmenopausal women to levels of premenopausal women. To test these hypotheses, brachial artery EDD will be measured in: 1) pre-and early perimenopausal women before and after short-term E2 suppression (GnRHant) and add-back of either transdermal E2 or placebo; and 2) postmenopausal women at baseline. To determine possible mechanisms for endothelial dysfunction, EDD will also be measured after oral BH4 supplementation alone and during AA infusion. Insight into the molecular events underlying the decrease in EDD will be determined by assessing the changes in endothelial cell expression of proteins involved in the regulation of cellular and systemic adaptations to E2 deficiency including BH4 biosynthesis and oxidative stress. [The results from this research should expand our earlier findings and elucidate further the mechanisms that mediate endothelial dysfunction across the stages of the menopause transition and whether these processes are triggered by E2 deficiency. Understanding these mechanistic defects will help to inform the critical window of intervention and guide future sex-specific interventions and therapies for the maintenance of vascular function and prevention of future cardiovascular diseases.]