Van Bergen Tine, Hu Tjing-Tjing, Etienne Isabelle, Reyns Geert E, Moons Lieve, Feyen Jean H M
ThromboGenics NV, Gaston Geenslaan 1, 3001 Heverlee, Belgium.
Department of Biology, Zoological Institute, KU Leuven, Leuven, Belgium.
Exp Eye Res. 2017 Dec;165:136-150. doi: 10.1016/j.exer.2017.09.012. Epub 2017 Sep 28.
The current standard of care in clinical practice for diabetic retinopathy (DR), anti-vascular endothelial growth factor (VEGF) therapy, has shown a significant improvement in visual acuity. However, treatment response can be variable and might be associated with potential side effects. This study was designed to investigate inhibition of placental growth factor (PlGF) as a possible alternative therapy for DR. The effect of the anti-PlGF antibody (PL5D11D4) was preclinically evaluated in various animal models by investigating different DR hallmarks, including inflammation, neurodegeneration, vascular leakage and fibrosis. The in vivo efficacy was tested in diabetic streptozotocin (STZ) and Akimba models and in the laser induced choroidal neovascularization (CNV) mouse model. Intravitreal (IVT) administration of the anti-PlGF antibody was compared to anti-VEGFR-2 antibody (DC101), anti-VEGF antibody (B20), VEGF-Trap (aflibercept) and triamcinolone acetonide (TAAC). Vascular leakage was investigated in the mouse STZ model by fluorescein isothiocyanate labeled bovine serum albumin (FITC-BSA) perfusion and in the Akimba model by fluorescein angiography (FA). Repeated IVT administration of the anti-PlGF antibody reduced vascular leakage, which was comparable to a single administration of VEGFR-2 inhibition in the mouse STZ model. PL5D11D4 treatment did not alter retinal ganglion cell (RGC) density, as demonstrated by Brn3a staining, whereas DC101 significantly reduced RGC number with 20%. Immunohistological stainings were performed to investigate inflammation (CD45, F4/80) and fibrosis (collagen type 1a). In the CNV model, IVT injection(s) of PL5D11D4 dose-dependently reduced inflammation and fibrosis, as compared to PBS treatment. Equimolar single administration of the anti-PlGF antibody and aflibercept (21 nM) and TAAC decreased leukocyte and macrophage infiltration with 50%, whereas DC101 and B20 (21 nM) had no effect on the inflammatory response. Similar results were observed in the mouse STZ model on the number of microglia and macrophages in the retina. Repeated administration of PL5D11D4 (21 nM) and TAAC similarly reduced fibrosis, while no effect was observed after equimolar DC101, B20 nor aflibercept administration (21 nM). In summary, the anti-PlGF antibody showed comparable efficacy as well-characterized VEGF-inhibitor on the process of vascular leakage, but differentiates itself by also reducing inflammation and fibrosis, without triggering a neurodegenerative response.
糖尿病视网膜病变（DR）临床实践中的当前标准治疗方法——抗血管内皮生长因子（VEGF）疗法，已使视力有显著改善。然而，治疗反应可能存在差异，并且可能与潜在的副作用相关。本研究旨在探究抑制胎盘生长因子（PlGF）作为DR的一种可能替代疗法。通过研究不同的DR特征，包括炎症、神经退行性变、血管渗漏和纤维化，在各种动物模型中对抗PlGF抗体（PL5D11D4）的效果进行了临床前评估。在糖尿病链脲佐菌素（STZ）和Akimba模型以及激光诱导脉络膜新生血管（CNV）小鼠模型中测试了体内疗效。将抗PlGF抗体的玻璃体内（IVT）给药与抗VEGFR - 2抗体（DC101）、抗VEGF抗体（B20）、VEGF - Trap（阿柏西普）和曲安奈德（TAAC）进行了比较。通过异硫氰酸荧光素标记的牛血清白蛋白（FITC - BSA）灌注在小鼠STZ模型中以及通过荧光素血管造影（FA）在Akimba模型中研究血管渗漏。抗PlGF抗体的重复IVT给药减少了血管渗漏，这与在小鼠STZ模型中单次给予VEGFR - 2抑制剂的效果相当。如通过Brn3a染色所示，PL5D11D4治疗未改变视网膜神经节细胞（RGC）密度，而DC101使RGC数量显著减少了20%。进行免疫组织化学染色以研究炎症（CD45、F4/80）和纤维化（I型胶原蛋白）。在CNV模型中，与PBS治疗相比，PL5D11D4的IVT注射剂量依赖性地减少了炎症和纤维化。抗PlGF抗体与阿柏西普（21 nM）和TAAC等摩尔单次给药使白细胞和巨噬细胞浸润减少了50%，而DC101和B20（21 nM）对炎症反应没有影响。在小鼠STZ模型中，视网膜中小胶质细胞和巨噬细胞的数量也观察到了类似结果。PL5D11D4（21 nM）和TAAC的重复给药同样减少了纤维化，而等摩尔的DC101、B20或阿柏西普给药（21 nM）后未观察到效果。总之，抗PlGF抗体在血管渗漏过程中显示出与特征明确的VEGF抑制剂相当的疗效，但通过减少炎症和纤维化而有所不同，且不会引发神经退行性反应。
