Lema I, Sobrino T, Durán J A, Brea D, Díez-Feijoo E
Instituto Galego de Oftalmoloxía, University of Santiago de Compostela, Spain.
Br J Ophthalmol. 2009 Jun;93(6):820-4. doi: 10.1136/bjo.2008.144253. Epub 2009 Mar 19.
BACKGROUND/AIMS: Tissue degradation in corneal thinning disorders, such as keratoconus (KC), involves the expression of inflammatory mediators. The purpose of this study was to determine the levels of proinflammatory cytokines and matrix metalloproteinase 9 (MMP-9) in tears from both eyes of unilateral keratoconus (KC) patients.
Thirty patients diagnosed as having asymmetrical KC (30 KC eyes, and 30 subclinical KC eyes) and 20 normal control subjects (one eye) were studied in a prospective, cross-sectional study. Keratoconus screening programmes were performed on these participants. Ten microlitres of tears was collected from each eye. The concentrations of cytokines (interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-alpha)) and MMP-9 were measured by ELISA.
Mean values for IL-6 levels were similar in KC and subclinical KC samples (5.5 (4.9 to 6.9) vs 5.7 (4.5 to 6.2) pg/ml, p = 0.131), but significantly higher in relation to the control group (2.2 (1.0 to 4.1) pg/ml, p<0.0001). Significant differences were found in TNF-alpha levels between KC and subclinical KC eyes (5.4 (4.1 to 6.8) vs 4.8 (4.2 to 6.0) pg/ml, p = 0.032) and control group (1.8 (1.5 to 2.3) pg/ml, p<0.0001). Increased values of MMP-9 were found in KC (59.4 (50.6 to 66.1) ng/ml) vs subclinical KC eye (7.0 (4.8 to 8.6) ng/ml) (p<0.0001). MMP-9 levels in the control group (6.1 (3.9 to 8.3) ng/ml) and subclinical KC were similar (p = 0.203).
IL-6 and TNF-alpha are overexpressed in the tears of subclinical and KC eyes. Increased MMP-9 levels were found only in the KC eye. These results indicate that the pathogenesis of KC may involve chronic inflammatory events.
背景/目的：角膜变薄性疾病，如圆锥角膜（KC），其组织降解涉及炎症介质的表达。本研究旨在确定单侧圆锥角膜（KC）患者双眼泪液中促炎细胞因子和基质金属蛋白酶9（MMP - 9）的水平。
在一项前瞻性横断面研究中，对30例被诊断为非对称性KC的患者（30只KC眼和30只亚临床KC眼）以及20名正常对照者（单眼）进行了研究。对这些参与者开展了圆锥角膜筛查项目。从每只眼睛收集10微升泪液。采用酶联免疫吸附测定法（ELISA）测量细胞因子（白细胞介素 - 6（IL - 6）和肿瘤坏死因子α（TNF - α））以及MMP - 9的浓度。
KC和亚临床KC样本中IL - 6水平的平均值相似（5.5（4.9至6.9）对5.7（4.5至6.2）皮克/毫升，p = 0.131），但与对照组（2.2（1.0至4.1）皮克/毫升，p<0.0001）相比显著更高。KC眼和亚临床KC眼中TNF - α水平存在显著差异（5.4（4.1至6.8）对4.8（4.2至6.0）皮克/毫升，p = 0.032），且与对照组（1.8（1.5至2.3）皮克/毫升，p<0.0001）相比也有差异。KC组（59.4（50.6至66.1）纳克/毫升）的MMP - 9值高于亚临床KC眼（7.0（4.8至8.6）纳克/毫升）（p<0.0001）。对照组（6.1（3.9至8.3）纳克/毫升）和亚临床KC组的MMP - 9水平相似（p = 0.203）。
IL - 6和TNF - α在亚临床和KC眼的泪液中过度表达。仅在KC眼中发现MMP - 9水平升高。这些结果表明KC的发病机制可能涉及慢性炎症事件。
