Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genetic association studies and pathological analysis of cardiovascular disease specimens implicate a role for the 5-lipoxygenase (5-LO)/leukotriene (LT) pathway in human cardiovascular disease. Previously, we had detected a role for this pathway in the incidence and severity of hyperlipidemic, cholate-containing, diet-induced aortic aneurysm in mice. The goal of the present study was to assess the importance of the 5-LO/LT pathway in angiotensin II (Ang II)-induced murine abdominal aortic aneurysm (AAA) formation. Mice with either genetic (5-LO(-/-)) or pharmacological (MK-0591) inhibition of the 5-LO pathway on an apolipoprotein E-deficient (apoE(-/-)) background were subjected to a normal chow diet with infusion of Ang II (500 ng/kg/min) for 28 days for assessment of AAA incidence and severity. Ang II-induced marked aortic wall remodeling with an incidence of 32, 29 and 40% AAA formation in 5-LO(-/-) apoE(-/-), 5-LO(+/+)apoE(-/-) and 5-LO(+/+)apoE(-/-) mice treated with FLAP inhibitor MK-0591, respectively, with no statistically significant differences in incidence or severity between groups. Abrogation of the 5-LO pathway in mice indicates a lack of role of leukotrienes in Ang II-induced AAA pathogenesis stressing the need for additional non-rodent AAA pre-clinical models to be tested.
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PMID:Angiotensin II-induced abdominal aortic aneurysm occurs independently of the 5-lipoxygenase pathway in apolipoprotein E-deficient mice. 1764 86

Leukotrienes (LTs) are arachidonic acid-derived lipid mediators involved in the pathogenesis and progression of diverse inflammatory disorders. The cysteinyl-leukotrienes LTC(4), LTD(4), and LTE(4) are important mediators of asthma, and LTB(4) has recently been implicated in atherosclerosis. Here we report that mRNA levels for the three key enzymes/proteins in the biosynthesis of cysteinyl-leukotrienes, 5-lipoxygenase (5-LO), 5-LO-activating protein (FLAP), and LTC(4) synthase (LTC(4)S), are significantly increased in the wall of human abdominal aortic aneurysms (AAAs). In contrast, mRNA levels of LTA(4) hydrolase, the enzyme responsible for the biosynthesis of LTB(4), are not increased. Immunohistochemical staining of AAA wall revealed focal expression of 5-LO, FLAP, and LTC(4)S proteins in the media and adventitia, localized in areas rich in inflammatory cells, including macrophages, neutrophils, and mast cells. Human AAA wall tissue converts arachidonic acid and the unstable epoxide LTA(4) into significant amounts of cysteinyl-leukotrienes and to a lesser extent LTB(4). Furthermore, challenge of AAA wall tissue with exogenous LTD(4) increases the release of matrix metalloproteinase (MMP) 2 and 9, and selective inhibition of the CysLT1 receptor by montelukast blocks this effect. The increased expression of LTC(4)S, together with the predominant formation of cysteinyl-leukotrienes and effects on MMPs production, suggests a mechanism by which LTs may promote matrix degradation in the AAA wall and identify the components of the cysteinyl-leukotriene pathway as potential targets for prevention and treatment of AAA.
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PMID:Increased expression of leukotriene C4 synthase and predominant formation of cysteinyl-leukotrienes in human abdominal aortic aneurysm. 2107 89