Basic research for the development of new therapeutic measures against progressive tubuloinetsrtitial injury.

(1)测定140例蛋白尿患者的尿MAC排泄量，并随访40个月。多因素分析表明，尿MAC排泄量的增加是肾损伤进展的独立危险因素。(2)从人近端肾小管上皮细胞中分离出刷状缘囊泡，并用SDS-PAGE和转移膜进行分析。BBV激活补体，并进一步分析结合C3b的组份。结果表明，补体被BBV激活，并有片段与C3b结合。BBV中补体激活物质的特性有待进一步分析。(3)巨噬细胞/单核细胞浸润是进行性肾小管间质损伤的主要机制之一。采用体内基因转移的方法对小鼠巨噬细胞侵袭策略进行了验证。(4)分析了近端肾小管细胞中存在的靶分子，包括中期因子(MK)、Toll样受体和小窝蛋白。所有这些分子都被证明是在体内和体外控制进行性肾损伤进展的靶点。(5)尤其是新型肝素结合生长因子MK在肾脏损伤过程中表达增加，MK基因敲除小鼠的肾小管间质损伤程度明显减轻。此外，反义寡核苷酸抑制MK在近曲小管的表达可显著减少体内肾脏损伤。(6)本研究的上述观察结果表明，肾脏损伤的发展涉及多个机制/分子，临床应用必须克服有效性、特异性、经济性和耐久性方面的障碍。

(1)Urinary MAC excretion was studied in 140 patients with proteinuria and followed up for 40 months. Multi-factorial analysis revealed that the increased urinary MAC excretion was an independent risk factor for progression of renal injury.(2)Brush border vesicles(BBVs) isolated from human proximal tubular epithelial cells were analyzed by SDS-PAGE and transfer membrane. BBVs activated complement and the fraction binding C3b was further analyzed. It was shown that complement was activated by BBVs and there were fragments to bind C3b. The further analysis is necessary to characterize complement activating substances in BBVs.(3)One of the main mechanisms of progressive tubulointerstitial injury is the infiltration of macrophages/monocytes. The strategy to iniibit macrophage infiltration was tested by using in vivo gene transfer. The effectiveness of this newly developed method was proven in a rat model of protein overlaod nephropathy.(4)The target molecules existing in the proximal tubular cells including midkine(MK), toll like receptors, and caveolin were analyzed. All of these molecules were proven to be a target to manipulate progression og the progressive renal injury in vivo and in vitro.(5)In particularly, MK, a novel heparin-binding growth factor, is increased in its expression during renal injury, and the extent of tubulointerstitial injury was significantly lessened in MK knock out mice. Furthermore, inhibition of MK expression by antisense-ODN in the proximal tubules significantly reduced renal injury in vivo.(6)All of the above observation obtained by the present research project revealed that several mechanismas/molecules were involved in the progression of renal injury, and for the clinical use, we must overcome the hurdles concerning efficacy, specificity, economy, and durability.