补体H 因子在妊娠相关血栓性微血管病肾损害发病机制中的作用研究

Pregnancy-associated thrombotic microangiopathy (P-TMA) is a group of acute and severe clinical syndrome, which could be life-threatening conditions of pregnant and lying-in women and newborns. Kidney is one of the most commonly affected organs in the disease. Endothelial injury is the principal mechanism of disease underlying distinct forms of P-TMA. Recent studies suggested that disorder of complement system activation could be involved in the development of P-TMA. Our preliminary work found that the complement alternative pathway was over-activated in the patients with renal injury due to P-TMA, in whom the low levels of plasma complement factor H (CFH, the major regulator of the complement alternative pathway) and CFH gene mutants were also identified. Therefore, we proposed that the dysfunctions of CFH could contribute to the development of renal injury due to P-TMA. In this study, we planned to investigate the complement components in the plasma, urine and kidney tissues from P-TMA patients based on our well-defined cohort, purify CFH from the patients’ plasma and apply them for bio-functional studies, and generate CFH mutant knock-in mouse and pregnancy induced hypertension mouse models to mimic the development of P-TMA. Thus, we will assess the complement system activation in the progress of the disease, better understand the role of CFH in the pathogenesis of renal injury due to P-TMA, and provide evidence for the prospective “Precision Medicine” in the field.

妊娠相关血栓性微血管病(TMA)是一组临床急重症，严重威胁孕产妇及新生儿健康，肾脏是其最常受累的器官之一。该病发病机制复杂，涉及多种原因导致的血管内皮细胞损害。近年研究显示，补体系统的异常活化可能参与该病的发病。申请者的前期工作发现，妊娠相关TMA肾损害患者体内存在补体旁路途径的过度激活，且大多数患者体内血循环中存在补体H因子（旁路途径的调节蛋白之一）的水平低下及基因突变。由此，我们推测，H因子的功能缺陷可能与妊娠相关TMA肾损害的发生发展密切相关。本课题利用本中心充足的临床资源，拟通过对妊娠相关TMA肾损害患者循环及肾脏组织局部补体水平的检测、纯化患者血浆中H因子及相关功能研究、建立补体H因子基因缺陷的小鼠模型及利用妊高症的小鼠模型，动态关注妊娠相关TMA发病过程不同时期中补体活化的影响，深入阐明补体H因子在妊娠相关TMA肾损害中的参与机制，为未来该领域的“精准靶向治疗"提供理论依据。

妊娠相关血栓性微血管病(TMA)是一组临床急重症，严重威胁孕产妇及新生儿健康，肾脏是其最常受累的器官之一。鉴于近年来妊娠相关TMA人群中补体激活的认识越来越得到认可，临床证据已较为充分，故本课题研究主体以构建妊娠相关TMA小鼠模型为主。在本基金的合作伙伴——美国宋文超教授建立的FH的SCR19-20区W1206R单点突变所致的TMA小鼠模型杂合型突变FH(W/R)背景下，申请者所在课题组研究发现：给予FH(W/R)小鼠抗VEGF抗体刺激，大多数小鼠出现蛋白尿，部分小鼠血小板降低；给予妊娠FH(W/R)小鼠及FH(W/W)小鼠左硝基精氨酸甲酯（L-NAME）刺激，发现注射当天始小鼠均出现血压升高，妊娠第18天均出现蛋白尿，LDH升高，血红蛋白降低及血清尿素氮升高，肾脏病理显示大部分出现肾小球基底膜内疏松层增宽。其中，妊娠FH(W/R)小鼠与妊娠FH(W/W)小鼠相比，血压、蛋白尿、LDH及血清尿素氮升高较明显及肾脏病理示病变较重，且妊娠FH(W/R)组中1/3小鼠肾脏病理示典型的TMA样改变（肾小球基底膜内疏松层增宽和内皮细胞肿胀）；加大L-NAME的注射剂量，延长注射天数并扩大样本量后发现，注射后妊娠FH(W/R)小鼠及FH(W/W)小鼠血压均升高，第25天均出现蛋白尿，LDH升高，血红蛋白降低及血清尿素氮升高，肾脏病理显示大部分出现肾小球基底膜内疏松层增宽。其中，妊娠FH(W/R)小鼠血压升高较妊娠FH(W/W)小鼠显著，且差异具有统计学意义。此外，肾脏病理也显示妊娠FH(W/R)小鼠的TMA样改变较妊娠FH(W/W)小鼠重，肾小球基底膜内疏松层宽度定量分析示妊娠FH(W/R)组内疏松层宽度显著高于妊娠FH(W/W)组，且有统计学差异。并且，妊娠FH(W/R)组有2/9只小鼠的肾脏TMA样病理损伤严重，内疏松层增宽程度达重度，且伴有内皮细胞增生及肿胀和系膜细胞溶解。综上所述，通过构建妊娠相关TMA小鼠模型，本课题发现在先天携带FHW1206R杂合突变的情况下，妊娠期合并其他因素刺激（如抗VEGF抗体，L-NAME），可诱导小鼠产生TMA样病变。