Impact of Menopause on the Aqueous Outflow Pathway

项目总结/摘要 青光眼是导致不可逆失明的主要原因，预计全球有1.12亿人患有青光眼 到2040年女性占青光眼人群的59%，强调需要了解性别特异性 青光眼的危险因素此外，雌激素水平、信号传导或代谢的改变也在青光眼中发挥作用 在两性中。在女性中，雌激素受体多态性与高眼压相关（一项研究显示， 青光眼的重要致病危险因素）。此外，绝经后妇女有1-3毫米汞柱高 眼内压（IOP）比绝经前妇女，而激素治疗含有雌激素降低 IOP。这些数据表明绝经和雌激素水平影响IOP，但机制尚不清楚。 IOP受许多因素影响，但房水流出阻力是关键决定因素，而这又主要是 由小梁网（TM）功能控制。有趣的是，流出阻力与TM刚度相关， 众所周知，更年期和雌激素水平会影响眼外许多组织的硬度， 雌激素水平改变影响IOP的可能机制。更年期也会改变基因表达， 许多基因受绝经期影响，已知会影响房水流出阻力。因此，假设 更年期通过硬化TM增加了房水流出阻力，从而增加了女性的 发生青光眼的风险，这些影响是由改变的基因表达谱介导的， 水流出通道。该提议在绝经的动物模型中提出了如下假设： 目标1将测量IOP和房水流出阻力。目标2将使用Atomic测量TM刚度 力显微镜。目的3将使用RNAseq评估房水流出途径组织中的基因表达。 该提案通过几种方法实现了这些目标：（A）它采用了一种行之有效的模型， 绝经，卵巢切除术（OVX）;和（B）将确定 局部雌激素治疗减轻了OVX的影响。这项建议也将调查是否外用雌激素 治疗影响雄性大鼠（9-10月龄）的IOP和房水流出阻力，着眼于 最终的临床翻译。在所有动物中，将使用回弹眼压计测量IOP 8周，随后 通过测量流出阻力（通过iPerfusion）和TM刚度（通过原子力显微镜）， 眼睛侧眼将用于评估：（1）雌激素水平，（2）TM结构和组成，或（3）基因 表情初步数据支持这一假设，表明IOP和房水流出阻力是 增加了OVX。这项提案将建立在这些数据的基础上，并期望证明更年期增加， TM硬度和改变基因表达在水流出途径组织，局部雌激素治疗， 阻止这些变化。这些发现将提供功能和机制的洞察协会 绝经和青光眼之间的关系，以及局部雌激素治疗作为青光眼治疗的益处。

Project Summary/Abstract Glaucoma is the leading cause of irreversible blindness and is projected to affect 112 million people worldwide by 2040. Women represent 59% of the glaucoma population, highlighting the need to understand sex-specific risk factors for glaucoma. In addition, altered estrogen levels, signaling, or metabolism play a role in glaucoma in both sexes. In women, estrogen receptor polymorphisms are associated with ocular hypertension (an important causal risk factor for glaucoma). Moreover, post-menopausal women have a 1-3 mmHg higher intraocular pressure (IOP) than pre-menopausal women, while hormone therapy containing estrogen reduces IOP. These data suggest that menopause and estrogen levels influence IOP, but the mechanism is unknown. IOP is affected by many factors, but aqueous outflow resistance is the key determinant, which in turn is primarily controlled by trabecular meshwork (TM) function. Intriguingly, outflow resistance correlates with TM stiffness, and it is known that menopause and estrogen levels affect stiffness of many tissues outside the eye, suggesting a possible mechanism by which altered estrogen levels affect IOP. Menopause also alters gene expression, with many genes affected by menopause known to influence aqueous outflow resistance. Thus, it is hypothesized that menopause increases aqueous outflow resistance by stiffening the TM, thus increasing a woman’s risk of developing glaucoma, and that these effects are mediated by altered gene expression profiles in the aqueous outflow pathway. This proposal addresses the hypothesis in an animal model of menopause as follows: Aim 1 will measure IOP and aqueous outflow resistance. Aim 2 will measure TM stiffness using Atomic Force Microscopy. Aim 3 will assess gene expression in aqueous outflow pathway tissues using RNAseq. This proposal achieves these aims using several approaches: (A) It employs a well-established model of menopause, ovariectomy (OVX), in female Brown Norway rats (9-10 months of age); and (B) It will determine if topical estrogen therapy mitigates the effects of OVX. This proposal will also investigate whether topical estrogen therapy affects IOP and aqueous outflow resistance in male rats (9-10 months of age), with an eye towards eventual clinical translation. In all animals, IOP will be measured using rebound tonometry for 8 weeks, followed by measurement of outflow resistance (via iPerfusion) and TM stiffness (via atomic force microscopy) in one eye. Contralateral eyes will be used to assess: (1) estrogen levels, (2) TM structure and composition, or (3) gene expression. Preliminary data support this hypothesis, showing that IOP and aqueous outflow resistance are increased by OVX. This proposal will build on these data and expects to demonstrate that menopause increases TM stiffness and alters gene expression in aqueous outflow pathway tissues, and that topical estrogen therapy prevents these changes. These findings will provide functional and mechanistic insight into the association between menopause and glaucoma, and the benefits of topical estrogen therapy as a treatment for glaucoma.