Department of Interdisciplinary Research in Science, Alexandru Ioan Cuza University of Iasi, Carol I Avenue, no. 11, 700506, Iasi, Romania.
Department of Ophthalmology, Faculty of Medicine, "Gr. T. Popa" University of Medicine and Pharmacy, Iasi, Romania.
Exp Eye Res. 2020 Jan;190:107897. doi: 10.1016/j.exer.2019.107897. Epub 2019 Dec 10.
Keratoconus (KC) is a controversial ophthalmological disease, often considered both multifactorial and multigenic with poor or not entirely understood etiopathogenesis. Corneal collagen crosslinking (CXL) procedure is the most common surgical therapy for KC which both slows corneal thinning and halts disease progression. While extensive studies provide consistent evidence on systemic oxidative stress in KC patients and animal models, little is known on the tear fluid oxidative stress markers such as antioxidant enzymes activity or lipid peroxidation markers. Also, little is known considering the oxidative status dynamics following CXL. In this way, we aimed to evaluate three oxidative stress markers in the tears of KC patients before and after CXL procedure. Total superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymatic activity and malondiladehyde (MDA) levels were assessed from the tears of 20 kC patients who received the recommendation for CXL procedure. Significantly decreased SOD activity (p = 0.0014) was observed in KC patients tears, as compared to age and sex-matched controls which could lead to significant lipid peroxidation boost (p < 0.001). Significantly higher GPx enzyme activity was observed in KC patients, as compared to control (p < 0.001), suggesting a compensatory response to intense lipid peroxidation. Following CXL, SOD activity significantly decreases and GPx activity extensively increases, as compared to baseline KC levels and controls (p < 0.001). This work provides additional evidence on oxidative stress status in the tears of KC considering general oxidative stress markers dynamics both before and after the CXL procedure. We also demonstrated that the CXL procedure could have further relevance in the management of this disorder.
圆锥角膜（KC）是一种有争议的眼科疾病，通常被认为是多因素和多基因的，其发病机制较差或不完全了解。角膜胶原交联（CXL）是 KC 的最常见手术治疗方法，可减缓角膜变薄并阻止疾病进展。虽然广泛的研究为 KC 患者和动物模型中的系统性氧化应激提供了一致的证据，但对于泪液中的氧化应激标志物，如抗氧化酶活性或脂质过氧化标志物的了解甚少。此外，对于 CXL 后氧化状态的动态变化也知之甚少。因此，我们旨在评估 CXL 前后 KC 患者泪液中的三种氧化应激标志物。从接受 CXL 推荐的 20 名 KC 患者的泪液中评估了总超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GPx）的酶活性和丙二醛（MDA）水平。与年龄和性别匹配的对照组相比，KC 患者的泪液中 SOD 活性显着降低（p=0.0014），这可能导致显着的脂质过氧化增加（p<0.001）。与对照组相比，KC 患者的 GPx 酶活性显着升高（p<0.001），表明对强烈的脂质过氧化有代偿性反应。与基线 KC 水平和对照组相比，CXL 后 SOD 活性显着降低，GPx 活性广泛增加（p<0.001）。这项工作提供了关于 CXL 前后一般氧化应激标志物动力学的 KC 泪液中氧化应激状态的额外证据。我们还证明，CXL 程序在这种疾病的治疗中可能具有更大的相关性。
