Wang Jing, Lin Jihong, Kaiser Ulrike, Wohlfart Paulus, Hammes Hans-Peter
5th Medical Department, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
R&D Diabetes Division, Research and Translational Medicine, Sanofi, Industriepark Höchst, 65926, Frankfurt, Germany.
Acta Diabetol. 2017 Apr;54(4):383-392. doi: 10.1007/s00592-016-0956-8. Epub 2017 Jan 9.
Ischemia-induced neovascularization is the key feature of proliferative diabetic retinopathy. Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory and proangiogenic cytokine, and its levels are elevated in the vitreous of patients with proliferative diabetic retinopathy. In this study, we aimed at investigating the relative potential of MIF in the ischemia-induced retinal neovascularization.
Both WT and MIF-knockout mice were subjected to the retinopathy of prematurity (ROP) model. Intraretinal vessel regrowth was assessed by whole-mount immunofluorescence, and preretinal neovascularization was analyzed in retinal vertical sections after periodic acid-Schiff staining in the hypoxic stage of the ROP model. Gene expression of selected proangiogenic and proinflammatory factors at postnatal day 13 (p13) was measured by real-time PCR. Vascular endothelial growth factor (VEGF) expression, recruitment of endothelial progenitor cells (EPCs) and microglial activation were analyzed with immunofluorescence.
MIF deficiency increased areas of vascular obliteration by 49%, reduced sprouting tips by 27% and inhibited preretinal angiogenesis by 35%. VEGF expression was reduced in Müller cells of MIF-knockout mice. MIF absence reduced gene expression of erythropoietin, tumor necrosis factor alpha and intercellular adhesion molecule-1 by 30, 70 and 50%, respectively, decreased the number of retinal EPCs by 37.5% and inhibited microglial activation in the hypoxic condition.
In conclusion, we found that MIF has proangiogenic and proinflammatory properties in retinal neovascularization. The proangiogenic role of MIF in ischemia-induced retinal neovascularization is associated with the expression of VEGF and erythropoietin, EPC recruitment and inflammation. Therefore, MIF has a potential role in the pathological angiogenesis of proliferative retinopathy.
缺血诱导的新生血管形成是增殖性糖尿病视网膜病变的关键特征。巨噬细胞移动抑制因子（MIF）是一种具有多种功能的促炎和促血管生成细胞因子，在增殖性糖尿病视网膜病变患者的玻璃体中其水平升高。在本研究中，我们旨在探究MIF在缺血诱导的视网膜新生血管形成中的相对作用。
将野生型和MIF基因敲除小鼠建立早产儿视网膜病变（ROP）模型。通过全层免疫荧光评估视网膜内血管再生，并在ROP模型缺氧期经高碘酸 - 希夫染色后，在视网膜垂直切片中分析视网膜前新生血管形成。通过实时PCR检测出生后第13天（p13）时选定的促血管生成和促炎因子的基因表达。用免疫荧光分析血管内皮生长因子（VEGF）表达、内皮祖细胞（EPC）募集和小胶质细胞活化情况。
MIF缺乏使血管闭塞面积增加49%，使发芽尖端减少27%，并抑制视网膜前血管生成35%。MIF基因敲除小鼠的Müller细胞中VEGF表达降低。MIF缺失分别使促红细胞生成素、肿瘤坏死因子α和细胞间黏附分子 - 1的基因表达降低30%、70%和50%，使视网膜EPC数量减少37.5%，并在缺氧条件下抑制小胶质细胞活化。
总之，我们发现MIF在视网膜新生血管形成中具有促血管生成和促炎特性。MIF在缺血诱导的视网膜新生血管形成中的促血管生成作用与VEGF和促红细胞生成素的表达、EPC募集及炎症有关。因此，MIF在增殖性视网膜病变的病理性血管生成中具有潜在作用。
