阻塞性睡眠呼吸暂停模式间歇低氧条件下内皮祖细胞参与内皮修复机制的研究

The prevalence of obstructive sleep apnea (OSA) in adults is about 4%. OSA is independent risk factor of a variety of cardiovascular diseases such as atherosclerosis, hypertension and coronary heart disease. The major pathophysiologic mechanism of vascular injury is the endothelial damage from intermittent hypoxia (IH) with OSA pattern. The maintenence and stability of functional endothelium depend on a dynamic balance between endothelial damage and repair. In this study, the repair mechanism associated with enthothelial progenitor cell (EPC) after endothelial damage is explored. For this, IH rat model and IH Transwell cell model with OSA pattern will be established, and then we will estimate the activation, recruitment, proliferation, homing, regulation, paraendocrine and aging of EPC. Oxidative/ anti-oxidative and Pre-/ anti- inflammtory factors will also be monitored. The number, function and synergic pathway with EPC of circulating endothelial cell and mesenchymal stem cell are to be measured. We will estimate the EPC recruitment influenced by nitrogen oxide and endothelial nitrogen oxide synthase. All the estimation and measurement will be repeated after discontinuation of IH, anti-oxidative/ anti-inflammatory intervention and in continuous hypoxia pattern, and comparation of associated parameters will also be performed. Clarification and reinforcement of repair mechanism can ameliorate endothelial damage and reduce OSA related morbidity, as its clinical implication. And pharmacological and pathophysiological insight will be provided for improvement of reparation after endothelial damage.

阻塞性睡眠呼吸暂停(OSA)患病率在成人中约4%。OSA是动脉粥样硬化、高血压和冠心病等众多心血管疾病的独立危险因素。其血管损伤主要病生理基础是OSA模式间歇低氧(IH)造成内皮损伤。OSA病人内皮功能维持与稳定是内皮损伤与修复间动态平衡。本研究在本课题组前期损伤研究的基础上探索以内皮祖细胞(EPC)为主的内皮损伤后修复机制。建造不同OSA模式IH大鼠模型和Transwell细胞模型，测定EPC动员、招募、增殖、归巢能力及其调节通道以及EPC旁分泌和衰老状态；测定氧化-抗氧化、炎症-抗炎症指标；测定循环内皮细胞和基质干细胞数目、功能和与EPC间协同作用；评价系统中一氧化氮(NO)和内皮型一氧化氮合酶(eNOS)对EPC动员招募的影响；并在IH状态解除后、抗氧化/抗炎症干预后和持续低氧(CH)模式下重复测定和比较。研究修复机制并加强修复将减轻OSA患者内皮损伤进而减少OSA相关合并症。

本研究在本课题组前期间歇低氧内皮损伤研究的基础上探索以内皮祖细胞 (EPC) 为主的内皮损伤后修复机制。研究修复机制并加强修复将减轻 OSA 患者内皮损伤进而减少 OSA 相关合并症。① 本课题组成功建立肺气肿合并间歇低氧大鼠模型。重叠组大鼠肺气肿程度和肺病理损伤程度均有所加重。② 重叠组大鼠肺泡灌洗液细胞分类特点示淋巴细胞在间歇低氧造成的慢性炎症中发挥重要作用。不管 IH 和肺气肿在机制上是否具有协同作用，重叠组大鼠较 IH 或肺气肿大鼠系统及内皮炎症反应更强烈，内皮损伤也更加严重，可能增加了动脉粥样硬化等心血管疾病风险。且重叠综合症产生的促炎状态和促凝状态可能会促进 EPC 动员增加。③ IH/ROX 模式暴露对左心射血功能有轻度损伤并促进左心重构，同时对肺动脉压有升高作用。④ 本研究首次应用肺气肿合并 IH 大鼠模型证明当肺气肿合并 IH 时肺血管平滑肌细胞增殖及肺血管新生肌化明显，两者在引起肺动脉高压过程中起协同作用。⑤ 肺气肿合并 IH，在 RhoA/ROCK 通路基因及蛋白的表达中发挥协同作用。而 RhoA/ROCK 通路在低氧肺血管收缩及结构中发挥重要作用，故肺气肿合并 IH 后进一步加重低氧血管收缩及肺血管重构，上述通路可能是 OS 发生严重 PH 的机制之一。⑥ 间歇低氧合并肺气肿组大鼠外周血 EPC 相对浓度及骨髓 EPC 占 MNCs 百分比最高。⑦ IH 介导 c-fos 激活，且随着再氧合时间延长炎症反应逐渐加重。⑧ 间歇低氧小鼠模型示轻度 IH 后，小鼠外周血 EPCs 的动员、招募、增殖、趋化、归巢和生成血管能力增强，而中、重度 IH 后反而大大减弱,导致内皮损伤与内皮祖细胞修复之间动态失衡，加重内皮损伤，增加心血管疾病发生风险。⑨ OSA 患者诱导动员招募大量无效 EPC ，但直接参与修复内皮的 ALDHloCD34+KDR+EPC 并未增加，尤其对于重度 OSA 患者甚至有可能减少， OSA 减弱了修复内皮可能性，加重内皮损伤，从而增加心血管事件风险。