Departments of Ophthalmology and Medical Biology, Amsterdam UMC, University of Amsterdam, Ocular Angiogenesis Group, Amsterdam Cardiovascular Sciences, Amsterdam Neuroscience, Amsterdam, The Netherlands.
The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK.
Acta Ophthalmol. 2019 Mar;97(2):214-224. doi: 10.1111/aos.13909. Epub 2018 Aug 31.
Glucocorticoids (GCs) are used as treatment in diabetic macular oedema, a condition caused by blood-retinal barrier (BRB) disruption. The proposed mechanisms by which GCs reduce macular oedema are indirect anti-inflammatory effects and inhibition of VEGF production, but direct effects on the BRB endothelium may be equally important. Here, we investigated direct effects of GCs on the endothelium to understand the specific pathways of GC action, to enable development of novel therapeutics lacking the adverse side-effects of the presently used GCs.
Primary bovine retinal endothelial cells (BRECs) were grown on Transwell inserts and treated with hydrocortisone (HC), dexamethasone (Dex) or triamcinolone acetonide (TA). Molecular barrier integrity of the BRB was determined by mRNA and protein expression, and barrier function was assessed using permeability assays. In addition, we investigated whether TA was able to prevent barrier disruption after stimulation with VEGF or cytokines.
Treatment of BRECs with GCs resulted in upregulation of tight junction mRNA (claudin-5, occludin, ZO-1) and protein (claudin-5 and ZO-1). In functional assays, only TA strengthened the barrier function by reducing endothelial permeability. Moreover, TA was able to prevent cytokine-induced permeability in human retinal endothelial cells and VEGF-induced expression of plasmalemma vesicle-associated protein (PLVAP), a key player in VEGF-induced retinal vascular leakage.
Glucocorticoids have differential effects in an experimental in vitro BRB model. TA is the most potent in improving barrier function, both at the molecular and functional levels, and TA prevents VEGF-induced expression of PLVAP.
糖皮质激素（GCs）被用作治疗糖尿病性黄斑水肿的药物，这种疾病是由血视网膜屏障（BRB）破坏引起的。GCs 减少黄斑水肿的机制被认为是间接的抗炎作用和抑制 VEGF 产生，但对 BRB 内皮细胞的直接作用可能同样重要。在这里，我们研究了 GCs 对内皮细胞的直接作用，以了解 GC 作用的特定途径，从而开发缺乏目前使用的 GCs 不良反应的新型治疗药物。
原代牛视网膜内皮细胞（BRECs）在 Transwell 插入物上生长，并分别用氢可体松（HC）、地塞米松（Dex）或曲安奈德（TA）处理。BRB 的分子屏障完整性通过 mRNA 和蛋白表达来确定，屏障功能通过通透性测定来评估。此外，我们还研究了 TA 是否能够在 VEGF 或细胞因子刺激后防止屏障破坏。
GCs 处理 BRECs 导致紧密连接 mRNA（claudin-5、occludin、ZO-1）和蛋白（claudin-5 和 ZO-1）的上调。在功能测定中，只有 TA 通过降低内皮通透性增强了屏障功能。此外，TA 能够防止细胞因子诱导的人视网膜内皮细胞通透性和 VEGF 诱导的质膜小泡相关蛋白（PLVAP）表达，PLVAP 是 VEGF 诱导的视网膜血管渗漏的关键蛋白。
糖皮质激素在实验性体外 BRB 模型中具有不同的作用。TA 在改善分子和功能水平的屏障功能方面最为有效，并且 TA 可预防 VEGF 诱导的 PLVAP 表达。
