Coronary artery dysfunction in OSA: Role of mineralocorticoid receptors

摘要 阻塞性睡眠呼吸暂停（OSA）是世界范围内的普遍病症，特别是在肥胖人群中，并且是一种严重的呼吸障碍。 心血管疾病（CVD）的独立危险因素，包括冠状动脉微血管功能障碍（CMD）。 目前可用的OSA治疗并没有一致地检测到CVD的预期改善， CMD，提示需要针对核心紊乱的机制进行辅助治疗 由OSA引起。因此，OSA诱导的肾素-血管紧张素-醛固酮系统（RAAS）激活可能会触发 过度的盐皮质激素受体（MR）信号传导，其在内皮功能障碍中起主要作用， 动脉粥样硬化因此，假设OSA诱导的CMD至少部分是由MR依赖性的 机制等为了检查MR在OSA诱导的CMD中的作用，将肥胖的C57 B1/6雄性和雌性小鼠分别接种于小鼠。 在休息期间暴露于间歇性缺氧（IH），OSA的小鼠模型，持续6周（短期）， 16周（长期），并接受常规类固醇MR拮抗剂（螺内酯）或新型 非甾体类MR拮抗剂（非那利酮），以评估IH诱导的CMD（SA 1）的MR依赖性可逆性。 为了研究MR抑制是否可以加速CMD恢复，将小鼠暴露于短期和长期的 IH后12周常氧（IH停止-模拟理想OSA治疗），伴或不伴并发 用MR拮抗剂（SA 2）治疗。为了检测血管细胞特异性MR的作用， 内皮细胞（EC）特异性和平滑肌细胞（SMC）特异性MR缺失将暴露于长时间的 术语IH（SA 3）。除了心脏功能、血液流变学和心功能外，还将在体内和离体评价冠状动脉功能。 压力和代谢评估。此外，免疫组织化学分析的冠状血管，沿着 将使用以下方法评估不同冠状动脉细胞群中的基因网络表达动力学 单核RNA测序（snRNA-seq）。雄性和雌性小鼠将被喂食高脂肪或对照饮食8 然后置于环境室中进行IH暴露（交替6.1%FIO2/21.0%FIO2 90秒：90 sec，在12个白天的时间内持续6或16周，并用螺内酯（20 mg/kg），非那利酮（1 mg/kg）， 或安慰剂。IH停止方案包括将暴露的动物从IH室中取出，并留在 常氧条件下培养12周。心脏功能将通过超声心动图检查，而血压 和冠状动脉血流储备速度（CFVR）将使用尾袖法/遥测和多普勒血流评估 速度系统。此外，还将进行胰岛素耐量试验和空腹血液和血脂分析。 评估。安乐死后，将切除冠状动脉并安装在钢丝肌描记器上进行功能检查。 研究或处理用于免疫组织学分析（包括内膜中层厚度、胶原纤维 分布，以及氧化应激和炎症的指数）或snRNA-seq.拟议的研究将阐明 磁共振信号在阻塞性睡眠呼吸暂停介导的冠状动脉功能障碍中的作用以及增强磁共振信号的可能途径 CMD可逆性，从而使MR拮抗剂成为OSA患者生物学上合理的治疗靶点。

Abstract Obstructive sleep apnea (OSA) is a prevalent condition worldwide, especially in people with obesity, and is an independent risk factor for cardiovascular disease (CVD), including coronary microvascular dysfunction (CMD). Current available OSA treatments have not consistently detected the anticipated improvements in CVD and CMD, suggesting the need for adjuvant therapies aimed at the mechanisms underlying the core disturbances induced by OSA. As such, OSA-induced renin-angiotensin-aldosterone system (RAAS) activation may trigger excessive mineralocorticoid receptor (MR) signaling, which play a major role in endothelial dysfunction and atherosclerosis. Thus, the hypothesis is that OSA-induced CMD is mediated, at least in part, by MR dependent mechanisms. To examine the role of MR in OSA-induced CMD, obese C57Bl/6 male and female mice will be exposed to intermittent hypoxia (IH) during the rest period, a mouse model of OSA, for 6 weeks (short-term) and 16 weeks (long-term) and treated with the conventional steroidal MR antagonist (spironolactone) or the novel non-steroidal MR antagonist (finerenone) to evaluate the MR-dependent reversibility of IH-induced CMD (SA1). To investigate whether MR inhibition can accelerate CMD recovery, mice will be exposed to short-and long-term IH followed by 12 weeks of normoxia (IH cessation – simulating ideal OSA treatment) with or without concurrent treatment with MR antagonists (SA2). To examine the role of vascular cell-specific MR, transgenic mice with endothelial cell (EC)-specific and smooth muscle cell (SMC)-specific deletions of MR will be exposed to long- term IH (SA3). Coronary artery function will be evaluated in vivo and ex vivo in addition to heart function, blood pressure and metabolic assessments. Moreover, immunohistological analysis of the coronary vessels, along with gene networks expression dynamics among different coronary artery cell populations will be evaluated using single-nucleus RNA sequencing (snRNA-seq). Male and female mice will be fed a high-fat or control diet for 8 weeks then housed in environmental chambers for IH exposures (alternating 6.1% FIO2/21.0%FIO2 90 sec:90 sec, for 6 or 16 weeks during 12 daylight hours, and treated with spironolactone (20mg/kg), finerenone (1mg/kg), or placebo. IH cessation protocol consists of removing the exposed animals for the IH chambers and left under normoxic conditions for 12 weeks. Heart function will be examined via echocardiography, while blood pressure and coronary flow reserve velocity (CFVR) will be assessed using tail cuff method/telemetry and doppler flow velocity system, respectively. Additionally, Insulin tolerance test and fasting blood and lipid profiles will be evaluated. After euthanasia, coronary arteries will be excised and mounted on a wire myograph for functional studies or processed for immunohistological analyses (including intima-media thickness, collagen fiber distribution, and indices of oxidative stress and inflammation) or snRNA-seq. The proposed studies will elucidate the role of MR signaling in OSA-mediated coronary artery dysfunction and potential approaches to enhance CMD reversibility, thereby enabling MR antagonists as biologically plausible therapeutic targets in OSA patients.