Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
J Ocul Pharmacol Ther. 2011 Dec;27(6):539-43. doi: 10.1089/jop.2011.0187. Epub 2011 Dec 2.
The kallikrein/kinin system uses two distinct serine proteases, plasma kallikrein and tissue kallikrein, to yield bradykinin and Lys-bradykinin (kallidin) from specific substrate kininogens. The kallikrein/kinin system is known to have a role in contact-activated coagulation mechanisms and in inflammatory responses, and recently has been shown to contribute to homeostatic and protective mechanisms in the cardiovascular and renal systems. This article reviews current knowledge of the ocular kallikrein/kinin system within the context of proposed roles for this system in other important organs and tissues. All components of the kallikrein/kinin system are present in the eye and are positioned to participate in key ocular functions. Plasma kallikrein binds to vascular endothelium and generates bradykinin, which may contribute to regulation of ocular blood flow, and, in excess, has been implicated in the pathogenesis of retinal edema in patients with proliferative diabetic retinopathy. Tissue kallikrein is expressed in retina, ciliary muscle, and trabecular meshwork cells and could be a significant factor in the protective mechanism of ischemic preconditioning, and in the modulation of aqueous dynamics. Improved understanding of the role of plasma and tissue kallikreins and kinins in such processes has the potential to identify significant new targets for the therapy of ocular dysfunction.
激肽释放酶/激肽系统使用两种不同的丝氨酸蛋白酶，即血浆激肽释放酶和组织激肽释放酶，从特定的底物激肽原中产生缓激肽和赖氨酸缓激肽（赖氨酰缓激肽）。激肽释放酶/激肽系统已知在接触激活的凝血机制和炎症反应中发挥作用，最近还被证明在心血管和肾脏系统的稳态和保护机制中发挥作用。本文综述了眼内激肽释放酶/激肽系统的现有知识，并探讨了该系统在其他重要器官和组织中可能发挥的作用。激肽释放酶/激肽系统的所有成分都存在于眼睛中，并能参与关键的眼部功能。血浆激肽释放酶与血管内皮结合并产生缓激肽，这可能有助于调节眼血流，而且在过量的情况下，与增殖性糖尿病性视网膜病变患者的视网膜水肿的发病机制有关。组织激肽释放酶在视网膜、睫状肌和小梁网细胞中表达，可能是缺血预处理保护机制和房水动力学调节的重要因素。更好地了解血浆激肽释放酶和组织激肽释放酶以及激肽在这些过程中的作用，有可能为眼部功能障碍的治疗确定重要的新靶点。
