促红细胞生成素在糖尿病视网膜病变中的作用

Diabetic retinopathy (DR), the most common microvascular complication of diabetes, is the leading cause of blindness in working-aged populations. In the past two decades, the prevalence of diabetes has increased due to effects of economic advancement, and an increase in the age of the population. Additionally, patients with diabetes are living longer with better medical treatment. The prevalence of DR increases with duration of diabetes. Diabetes and its complications are becoming a major public health care problem and also affect economic development. There are many medical interventions available; however the efficacy of these treatments is uncertain. Erythropoietin (EPO) is a multifunctional cytokine and has been found to be highly expressed in diabetic patients. Due to its angiogenic effects, it is uncertain whether EPO is a physiologic response to DR or a pathogenic feature of DR. We are planning to uncover the molecular mechanism of EPO in angiogenesis and determine its role in the progression of DR. Molecular and cellular biotechnologies and genetic techniques will be combined to study EPO's effect on blood vessel both from in vitro and in vivo levels. We will try to define whether EPO works through multiple mechanisms, receptors or functional domains and downstream signals to mediate its myriad effects including erythropoieses, tissue protection and angiogenesis. Our goal is to determine whether we can identify these mechanisms and then harness them to improve EPO's application in disease treatment through specific targeting of its pathogenic effect. We aim to find new drug target and potential therapy candidate for the treatment of DR.

糖尿病视网膜病变是最常见的糖尿病并发症，为工作年龄人群中首要致盲疾病，还没有很好的治疗药物。由于经济的发展、生活条件的改善，糖尿病患者越来越多。随着医疗条件的提高，糖尿病患者的生存时间增长，并发视网膜病变的几率越高。因此，糖尿病和糖尿病视网膜病变将成为严重的公共健康问题，并影响社会经济的发展。促红细胞生成素（Erythropoietin，EPO）是一个多功能细胞因子，在糖尿病视网膜病变眼球中高表达。由于其促进血管增生的作用，因此关于EPO在糖尿病视网膜病变中，究竟是一个保护因子还是致病因子存在争议。我们计划综合运用细胞生物学、分子生物学和遗传学实验手段，从体外和体内两个角度来研究EPO促进血管增生的分子机制，探索EPO是否通过不同的机制发挥其促红细胞生成、组织保护和血管增生的功能，确定EPO在糖尿病视网膜病变中的作用，为寻找治疗糖尿病视网膜病变的药物靶点和药物开发奠定基础。

关于EPO在糖尿病视网膜病变发病机理中的作用存在争议，主要是因为EPO在视网膜病变中的具体作用机制不清楚。为了解EPO对血管和神经的具体作用和机制，我们从EPO的分子生物学信号通路着手，重组表达了人EPO，研究EPO对人视网膜血管内皮细胞（HREC）的调控。首先我们通过RT-PCR和Western Blot研究了HREC中 EPO受体的表达情况，确认在HREC中存在EPO受体表达，继而通过基因沉默，看是否两个受体都参与EPO调控HREC。建立了体外培养HREC细胞单层通透性改变实验，研究EPO对血管通透性的调控。通过血管内皮细胞管腔形成实验，我们确认了EPO可以促进HREC形成管腔，表明EPO可以促进HREC细胞形成新的血管。为了在体内验证体外的机制研究结果，我们采用STZ诱导，建立了糖尿病动物模型。目前糖尿病视网膜病变的诊断主要是靠眼底造影，而且存在一定的人为主观性。我们收集了糖尿病患者的血样，期望通过BioMarker的研究，能够找到可以作为糖尿病视网膜病变临床辅助的BioMarker，这样可以做到早早诊断，对患者做到尽早治疗，达到精准医疗。通过ELISA，我们检测了病人血样中的EPO蛋白含量，发现糖尿病视网膜病变患者血样中的EPO含量较无视网膜病变患者要高。糖尿病视网膜病变和糖尿病足都是糖尿病的并发症，均由长期高血糖引起血管病变导致供养、氧不足，引起组织和神经坏死的结果。我们研究发现这两种疾病的严重程度呈现明显正相关，表明虽然两者发病机理存在一定的相关性，但是可能也存在一些未知的不同病理因素。两者可以作为互相参照，对患者的及时诊、疗具有重要的参考价值。