Oxidative stress in human aorta of patients with advanced aortoiliac occlusive disease

Abstract Introduction: Oxidative stress seems to be a role in the atherosclerosis process, but research in human beings is scarce. Objective: To evaluate the role of oxidative stress on human aortas of patients submitted to surgical treatment for advanced aortoiliac occlusive disease. Methods: Twenty-six patients were divided into three groups: control group (n=10) formed by cadaveric organ donors; severe aortoiliac stenosis group (patients with severe aortoiliac stenosis; n=9); and total aortoiliac occlusion group (patients with chronic total aortoiliac occlusion; n=7). We evaluated the reactive oxygen species concentration, nicotinamide adenine dinucleotide phosphate-oxidase, superoxide dismutase and catalase activities as well as nitrite levels in samples of aortas harvested during aortofemoral bypass for treatment of advanced aortoiliac occlusive disease. Results: We observed a higher level of reactive oxygen species in total aortoiliac occlusion group (48.3±9.56 pmol/mg protein) when compared to severe aortoiliac stenosis (33.5±7.4 pmol/mg protein) and control (4.91±0.8 pmol/mg protein) groups (P<0.05). Nicotinamide adenine dinucleotide phosphate oxidase activity was also higher in total aortoiliac occlusion group when compared to the control group (3.81±1.7 versus 1.05±0.31 µmol/min.mg protein; P<0.05). Furthermore, superoxide dismutase and catalase activities were significantly higher in the severe aortoiliac stenosis and total aortoiliac occlusion groups when compared to the control cases (P<0.05). Nitrite concentration was smaller in the severe aortoiliac stenosis group in comparing to the other groups. Conclusion: Our results indicated an increase of reactive oxygen species levels and nicotinamide adenine dinucleotide phosphate-oxidase activity in human aortic samples of patients with advanced aortoiliac occlusive disease. The increase of antioxidant enzymes activities may be due to a compensative phenomenon to reactive oxygen species production mediated by nicotinamide adenine dinucleotide phosphate oxidase. This preliminary study offers us a more comprehensive knowledge about the role of oxidative stress in advanced aortoiliac occlusive disease in human beings.

Coexpression of cyclooxygenase-2 and matrix metalloproteinases in human aortic atherosclerotic lesions

Inflammation appears to have a major role in the development of atherosclerosis. Cyclooxygenase-2 (COX-2) is involved in the inflammatory response via the generation of prostanoids that, in turn, are involved in the production of matrix metalloproteinases (MMPs). This study aimed to investigate atherosclerosis in human aortas for in situ tissue distribution of COX-2, MMPs including MMP-9 and membrane type 1 MMP (MT1-MMP), and tissue inhibitor of metalloproteinase-2 (TIMP-2). Immunohistochemical studies were performed on atherosclerotic lesions of aortas from patients with aortic aneurysms (n = 4) and dissections (n = 3) by using antibodies to COX-2, MMP-9, MT1-MMP, and TIMP-2. Control tissues were obtained from traumatically dissected aortas (n = 2). All specimens from diseased aortas had atherosclerotic lesions ranging from fatty streak to atheromatous plaques. In control, there was no expression of COX-2, MMP-9, and MT1-MMP in all aortic layers. Immunoreactivity for COX-2 was predominantly noted in macrophages and smooth muscle cells (SMCs) of the intima including atherosclerotic plaque itself and the medial layer of the plaque base, as well as in SMCs and endothelial lining of the vasa vasorum in the adventitia. Immunoreactivity for MMP-9 and MT1-MMP was found in the same distribution as that of COX-2. Additionally, the expression of TIMP-2 increased in relation to MMP-9 expression. This study demonstrates that COX-2 is coexpressed with MMP-9 and MT1-MMP, not only by macrophages and SMCs in atherosclerotic lesions, but also in endothelial lining of the vasa vasorum of human aortas. Thus, vascular inflammatory reactions may influence extracellular matrix remodeling by coactivation of MMPs in the development of atherosclerosis and, in turn, the progression of disease.