吸入型高分子聚合物负载S-阿司匹林缓释微球的构建及其在肺动脉高压靶向治疗中的应用研究

Numerous studies have demonstrated that hydrogen sulfide (H2S), a novel gaseous mediator plays pivotal roles in the development and progression of pulmonary hypertension (PH). However, there is still a long way to go before H2S is used to treat PH. Nowadays, one of the critical issues is lack of safe and effective H2S donor drugs. Therefore, the present study is aimed to prepare and characterize dry-powder inhalable glycol chitosan-coated poly(lactic-co-glycolic acid) (PLGA) microspheres (MSs) containing S-aspirin (ACS-14), a novel H2S donor. With bio-degradable, high molecular weight polymer microspheres mediated delivery of ACS-14, targeted and slow release of H2S in lungs will be achieved. The anti-inflammatory, anti-oxidant and anti-proliferative effects of ACS-14 MSs as well as the restoration of impaired endothelial function by ACS-14 MSs will be evaluated in cell culture under hypoxia condition or in a rat model of hypoxia-induced PH. The underlying mechanisms with respect to the signaling pathways of transcriptional factors, HIF-1α and/or NF-κB will also be investigated. Finally, we will compare the efficacy and advantage of inhalable ACS-14 MSs with oral administration of sildenafil or intraperitoneally injection of conventional H2S donor drugs. The present study will not only provide a novel therapeutic strategy targeted for PH but also find an innovative approach to develop H2S donor drugs.

气体介质硫化氢具有延缓肺动脉高压（PH）进展的积极作用，然而在PH的临床治疗中应用硫化氢，仍面临着诸多挑战，其中，急需解决的关键问题之一是目前缺乏安全有效的硫化氢供体。本课题拟利用生物可降解、高分子聚合物缓释微球载体技术，负载新型硫化氢供体——S-阿司匹林（ACS-14），制成干粉吸入剂型，实现肺部靶向给药和组织局部缓释硫化氢。然后，从以下三个方面开展研究：1）检测载药微球的结构、药动力学、安全性和靶向性；2）分别在细胞低氧损伤模型和慢性缺氧诱导的PH动物模型中，观察ACS-14微球改善内皮功能、抗炎、抗氧化应激和抗增殖作用，及其与转录因子HIF-1α/NF-κB信号通路的关系；3）将气道吸入型ACS-14微球，与口服西地那非或腹腔注射常规硫化氢供体进行比较，进一步评估微球制剂靶向治疗PH的优势。本研究不仅为肺动脉高压提供了 新型的靶向治疗方法，也为研发硫化氢供体药物拓展了思路。

近年来的研究显示：新型气体介质——硫化氢与肺动脉高压的发生发展密切相关。由于目前缺乏安全有效的硫化氢供体药物，将该气体应用于肺动脉高压的临床治疗，仍面临着多方面的挑战。因此，本研究利用微流控技术平台，构建了负载的硫化氢释放型阿司匹林（ACS14）的聚乳酸-羟基乙酸共聚物（PLGA）吸入型多孔微球。首先，我们评估了这种载药微球的形态、大小、表征、释放H2S的药动力学特性和肺组织靶向性。然后，分别在细胞模型和野百合碱诱导的肺动脉高压动物模型中，观察载药微球改善肺动脉高压的作用，及其与内皮间质转化的关系和可能的分子机制。我们的研究结果显示：基于微流控技术的ACS14载药微球呈多孔球形，几何直径和空气动力学直径分别为24μm和4.4μm，具有良好的载药率、包封率、缓释性能和空气动力学特征，无明显细胞毒性，适于肺部吸入给药。在人肺动脉内皮细胞(HPAECs)中，ACS14微球可呈剂量依赖性抑制TGF-β1诱导的内皮间质转化(EndMT)以及相关的NF-κB-Snail信号通路。在野百合碱诱导的大鼠肺动脉高压模型中，每日吸入ACS14微球可显著抑制NF-κB-Snail信号通路，减轻肺动脉内皮间质转化，进而改善肺动脉血管重构和肺动脉压力。吸入ACS14微球靶向治疗肺动脉高压的疗效与口服西地那非相当。总之，本研究利用微流控技术构建了一种缓释硫化氢且适于呼吸道给药的ACS14 PLGA微球， ACS14微球不仅提高了硫化氢供体药物的肺靶向性和安全性，还通过抑制NF-κB-Snail信号通路，减轻肺动脉内皮间质转化，增强了硫化氢的抗肺动脉高压疗效。本研究不仅为防治肺动脉高压提供了新型的治疗方案，也为研发硫化氢供体药物拓展了思路。