Zhou Yi Jun, Wang Jia He, Li Li, Yang Hong Wu, Wen De Liang, He Qin Cheng
Department of Endocrinology and Metabolism, Fourth Affiliated Hospital, China Medical University, Shenyang 110032, PR China.
Biochem Biophys Res Commun. 2007 Nov 9;363(1):30-6. doi: 10.1016/j.bbrc.2007.08.134. Epub 2007 Aug 31.
Emerging evidence now indicates that the 5-lipoxygenase (5-LO) pathway play a role in the pathogenesis of atherosclerosis and restenosis. The expression of 5-LO by activated macrophages in symptomatic plaques leads to leukotriene B(4) (LTB(4)) accumulation and enhanced synthesis and release of matrix metalloproteinases (MMPs) that can promote plaque rupture. However, the role of 5-LO pathway in diabetic vascular disease has not been previously reported. Thus, the present study was designed to analyze the expression of 5-LO in carotid plaques of diabetic patients and to investigate the possible role of 5-LO pathway in the pathogenesis and progression of diabetic atherosclerosis. Atherosclerotic plaques from 60 patients undergoing carotid endarterectomy were divided into non-diabetic and diabetic group. Plaques were analyzed for 5-LO, MMP-2 and MMP-9 by immunohistochemical, Western blot, and densitometric analyses, whereas zymography was used to detect MMP activity. Immunocytochemistry was also used to identify CD68+macrophages, CD3+T-lymphocytes, and HLA-DR+inflammatory cells. LTB(4) were quantified by enzyme-linked immunosorbent assay. 5-LO showed abundant immunoreactivity in human atherosclerotic carotid lesions, and was colocalized with macrophage infiltrates in atherosclerotic intima. 5-LO expression was higher in diabetic compared with non-diabetic plaques and was associated with increased MMP-2 and MMP-9 expression. Follow-up analyze with zymography assay revealed MMP activity was elevated in diabetic compared with non-diabetic plaques. Notably, in contrast to non-diabetic plaques, LTB(4) levels were significantly increased in diabetic plaques by enzyme-linked immunosorbent assay. These results suggest that overexpression of 5-LO and LTB(4) in atherosclerotic plaques possibly promote MMP-induced plaque rupture in diabetes. Hence, anti-LTs may be useful, not only in reducing atherogenesis, but also in the prevention and treatment of acute atherothrombotic events in diabetic patients.
新出现的证据表明，5-脂氧合酶（5-LO）途径在动脉粥样硬化和再狭窄的发病机制中起作用。有症状斑块中活化巨噬细胞表达的5-LO会导致白三烯B4（LTB4）蓄积，并增强基质金属蛋白酶（MMPs）的合成与释放，而MMPs可促进斑块破裂。然而，5-LO途径在糖尿病血管疾病中的作用此前尚未见报道。因此，本研究旨在分析糖尿病患者颈动脉斑块中5-LO的表达情况，并探讨5-LO途径在糖尿病动脉粥样硬化发病机制及进展中的可能作用。将60例行颈动脉内膜切除术患者的动脉粥样硬化斑块分为非糖尿病组和糖尿病组。通过免疫组织化学、蛋白质印迹法和光密度分析对斑块进行5-LO、MMP-2和MMP-9分析，而用酶谱法检测MMP活性。免疫细胞化学也用于鉴定CD68+巨噬细胞、CD3+T淋巴细胞和HLA-DR+炎症细胞。通过酶联免疫吸附测定法对LTB4进行定量。5-LO在人类动脉粥样硬化颈动脉病变中显示出丰富的免疫反应性，并与动脉粥样硬化内膜中的巨噬细胞浸润共定位。与非糖尿病斑块相比，糖尿病斑块中5-LO表达更高，且与MMP-2和MMP-9表达增加相关。酶谱分析的随访分析显示，与非糖尿病斑块相比，糖尿病斑块中的MMP活性升高。值得注意的是，与非糖尿病斑块相比，通过酶联免疫吸附测定法发现糖尿病斑块中的LTB4水平显著升高。这些结果表明，动脉粥样硬化斑块中5-LO和LTB4的过度表达可能促进糖尿病中MMP诱导的斑块破裂。因此，抗白三烯药物可能不仅有助于减少动脉粥样硬化的发生，还可用于预防和治疗糖尿病患者的急性动脉粥样血栓形成事件。
