地塞米松与抗粘附分子缀合：增强疗效减弱副作用的靶向纳米策略

Dex is the most effective anti-inflammatory glucocorticoid in treating chronic inflammation, acute inflammation, peritoneal adhesion, cardio-pulmonary bypass, acute infection, rheumatoid arthritis, primary immune thrombocytopenia, perioperative immuno¬suppression of cardiac transplantation and rejection of the transplanted organ. However, the clinical efficacy of Dex is limited by osteoporosis and thrombosis, the most serious side effects. Recently, anti-adhesion RGDS, RGDV and RGDF were covalently conjugated with Dex, prepared three nano-medicines to the mentioned side effects. However, the inflammatory targeting of the conjugates remains to be elucidated. This project will covalently conjugate Dex with Lys(Arg- Gly-Asp-Val)Glu-Asp-Gly, Lys(Arg-Gly-Asp-Val)His-Gly-Glu, Lys(Arg-Gly-Asp- Val)His-Gly-Glu, Lys(Arg-Gly-Asp-Phe)Glu-Asp-Gly, Lys(Arg-Gly-Asp-Phe)His- Gly-Glu and Lys(Arg-Gly-Asp-Phe)His-Gly-Glu to construct 6 delivery systems, 5a-f, of inflammatory targeting. To limit investigation risk, this project prepared a delivery system 5a and evaluated its activities in inhibiting inflammation and prolonging cardiac muscle living time. It was found that the minimal effective dose of 5a in inhibiting inflammation and prolonging cardiac muscle living time are 1/850 and 1/25 of that of Dex, respectively. By preparing delivery system 5a-f, evaluating therapeutic actions and side reactions, and exploring inflammatory targeting this project will able to provide targeting delivery system of Dex with high efficacy and low side reaction for clinical therapy of Dex.

治疗各种炎症和预防排斥反应时，地塞米松是疗效最好应用最广的一线药物。地塞米松可诱发骨质疏松症和血栓症，限制了它的应用，目前没法克服。我国不仅生产全球90%地塞米松，也是地塞米松应用大国。克服两种副反应对国家有实际贡献。申请人曾用抗血栓RGD-四肽共价缀合地塞米松形成纳米药物，克服了两种副反应，只是未确认靶向性。本课题拟以Lys为桥将抗血栓RGD-四肽和增强免疫抑制的尿毒素三肽生成6种八肽与地塞米松共价构建靶向递送体系5a-f。以体系5a为代表的前期评价显示，5a抗炎和延长心肌存活的最低有效剂量分别是地塞米松的1/850和1/25，远优于RGD-四肽与地塞米松的缀合物，确认靶向递送体系可行。本课题拟制备5a-f、评价活性和副反应、揭露炎症靶向。实施本课题，既可为患者提供疗效好毒副作用小的靶向递送地塞米松的纳米体系，又可稳定我国生产地塞米松的大国地位。 因而具有科学意义、临床意义和经济价值

项目背景:对于炎症和排斥反应, 地塞米松是广泛应用的一线药物之一。诱发骨质疏松症和血栓症则是地塞米松的致命性副作用。在保留疗效的前提下避免致命性副作用是地塞米松的临床需求。用寡肽递送地塞米松, 通过降低有效剂量避免副作用是本项目的基本策略。主要内容:以Lys为连接臂将塞米松分别与Arg-Gly- Asp-Val及Glu-Asp-Gly, Arg-Gly-Asp-Phe及Glu-Asp-Gly, Arg-Gly-Asp-Val及His-Gly-Glu, Arg-Gly-Asp-Phe及His-Gly-Glu, Arg-Gly-Asp-Val及His-Gly-Lys和Arg- Gly-Asp-Phe及His-Gly-Lys偶联制备化合物5a, 5b, 5c, 5d, 5e和5f; 用电镜表征化合物5a-f的纳米形貌;在BALB/C小鼠模型上评价化合物5a-f延长移植的心肌存活时间的效果, 在ICR小鼠模型上评价化合物5a-f对二甲苯诱发的耳肿胀的抑制作用; 在SD大鼠模型上评价化合物5a-f的抗血栓作用, 在ICR小鼠模型上比较地塞米松与化合物5a-f治疗对小鼠股骨的影响。重要结果: 1)建立了化合物5a-f的制备方法; 2)在浓度为1.43×10-6M的超纯水溶液中化合物5a-f都组装为粒径小于100nm不会被巨噬细胞吞噬的纳米粒; 3)在BALB/C小鼠模型上口服剂量为0.1μmol/kg/天, 连续给药15天, 5a-f使90%心肌存活17天, 而地塞米松只使70%移植的心肌存活16天; 4) 在二甲苯诱发的耳肿胀ICR小鼠模型上, 在0.1μmol/kg剂量下化合物5a-f对炎症反应的抑制率为77%-79%, 在1.43μmol/kg剂量下地塞米松对炎症反应的抑制率只有50%; 5) 剂量为1.4μmol/kg/天时地塞米松连续治疗15天诱发小鼠的骨质疏松症, 剂量为0.1μmol/kg/天时化合物5a-f连续治疗15天没有诱发小鼠骨质疏松症的风险; 6) 在0.99μmol/kg剂量下地塞米松诱发血栓症, 在0.99μmol/kg剂量下化合物5a-f则显示抗血栓活性。科学意义:本项目建立的偶联的模式为地塞米松保留活性避免副作用提供了科学依据。