Supplementary Material for: High Vitreous Concentration of IL-6 and IL-8, but Not of Adhesion Molecules in Relation to Plasma Concentrations in Proliferative Diabetic Retinopathy

<b><i>Background/Aim:</i></b> Inflammatory markers have been observed in proliferative diabetic retinopathy (PDR). We assessed vitreous concentrations of adhesion molecules and cytokines in PDR and non-diabetic controls and plasma concentrations to differentiate local inflammation from the breakdown of the blood-retina barrier. <b><i>Methods:</i></b> 38 patients with PDR and 16 controls with macular hole or epiretinal membrane underwent vitrectomy. Vitreous and plasma soluble adhesion molecules [sE-selectin, intercellular adhesion molecule (sICAM)-1 and -3, platelet-endothelial cell adhesion molecule (sPECAM)-1, sP-selectin, vascular cell adhesion molecule (sVCAM)-1] and cytokines [interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12 (p70), tumour necrosis factor-α and -β, γ-interferon] were detected by the multiplex assay. <b><i>Results:</i></b> Levels of IL-6 and IL-8 were 26-fold (p = 0.001) and 6-fold higher (p = 0.001) in vitreous than in plasma in PDR. Vitreous IL-10 (p = 0.004), sPECAM-1, sE-selectin, sICAM-1 and sVCAM-1 were higher in PDR than controls (p = 0.001 for all). Adhesion molecule concentrations in vitreous in PDR were less than 10% of those in plasma. IL-10 was lower in vitreous than plasma (3.0 vs. 12.8 pg/ml, p = 0.007), and the vitreous IL-10/IL-8 ratio was significantly lower in PDR than in controls (0.10 vs. 0.55 pg/ml, p = 0.003). <b><i>Conclusion:</i></b> The elevated IL-6 and IL-8 levels in vitreous, but not in plasma, are evidence favouring local over systemic inflammation in PDR. Furthermore, there was imbalance between inflammatory and anti-inflammatory cytokines in the vitreous.

**背景与研究目的：** 已有研究在增生性糖尿病视网膜病变（proliferative diabetic retinopathy, PDR）中观察到炎症标志物。本研究旨在检测PDR患者与非糖尿病对照受试者的玻璃体黏附分子与细胞因子浓度，并检测血浆浓度，以区分局部炎症与血视网膜屏障（blood-retina barrier）破坏。
**方法：** 38例PDR患者及16例伴有黄斑裂孔或视网膜前膜的对照受试者接受了玻璃体切割术。采用多重检测法对玻璃体与血浆中的可溶性黏附分子[可溶性E-选择素（sE-selectin）、细胞间黏附分子（sICAM）-1与-3、血小板-内皮细胞黏附分子（sPECAM）-1、可溶性P-选择素（sP-selectin）、血管细胞黏附分子（sVCAM）-1]及细胞因子[白细胞介素（IL）-1β、IL-2、IL-4、IL-5、IL-6、IL-8、IL-10、IL-12（p70）、肿瘤坏死因子-α、-β及γ-干扰素]进行了检测。
**结果：** PDR患者玻璃体中的IL-6与IL-8水平分别较血浆升高26倍（p=0.001）与6倍（p=0.001）。PDR患者玻璃体中的IL-10（p=0.004）、sPECAM-1、sE-selectin、sICAM-1及sVCAM-1水平均高于对照组（所有指标p=0.001）。PDR患者玻璃体中的黏附分子浓度不足血浆中的10%。玻璃体IL-10水平低于血浆（3.0 vs 12.8 pg/ml，p=0.007），且PDR患者的玻璃体IL-10/IL-8比值显著低于对照组（0.10 vs 0.55 pg/ml，p=0.003）。
**结论：** 玻璃体中升高的IL-6与IL-8水平（而非血浆中），为PDR的炎症以局部炎症而非全身炎症为主提供了证据。此外，玻璃体中促炎与抗炎细胞因子存在失衡。