Abstract

Oxidative stress to cardiovascular cells induced by an interaction of multiple cytokines and adhesion molecules has been postulated to be responsible for cardiovascular disease. Since nuclear factor-kB (NFkB) also plays a pivotal role in the coordinated transactivation of cytokine and adhesion molecule genes, we utilized oligodeoxynucleotides (ODNs) as "decoy" cis-elements that block the binding of nuclear factors to promoter regions of targeted genes, resulting in the inhibition of gene transactivation. Indeed, transfection of NFkB decoy ODNs into coronary artery effectively prevented transactivation of essential cytokine and adhesion molecule protein expression, and thereby protected the myocardium from infarction. Transfection of NFkB decoy ODNs into balloon-injured carotid artery or porcine coronary artery markedly reduced neointimal formation. Thus, a clinical trial using NFkB decoy ODNs to treat restenosis was started in 2002. Recently, the therapeutic target utilizing NFkB decoy has been expanded to glomerulonephritis, rheumatoid arthritis, atopic dermatitis and osteoporosis. Moreover, the clinical trials to treat RA patients were initiated in 2003 and a Phase I/IIa human clinical trial using NFkB decoy ODNs to treat atopic dermatitis was initiated in December 2001. Topical application of NFkB decoy ODNs exhibited marked therapeutic effects on the facial skin condition of patients with atopic dermatitis. The covalently modified ODNs were developed by enzymatically ligating two identical molecules, thereby preventing their degradation by exonucleases. Indeed, the modified decoy ODNs possess increased nuclease resistance and are transported more efficiently into cells. Although there are still unresolved issues, decoy ODN drugs should become a reality. Type 2 diabetes is associated with a two to four-fold increased risk of both coronary heart disease and stroke. Dysfunction of endothelial cells (EC) is known to promote abnormal vascular growth such as that in atherosclerosis and arteriosclerosis, and has been postulated as an initial trigger of the progression of atherosclerosis in patients with diabetes mellitus. Moreover, hyperglycemia is an independent risk factor for the development of cardiovascular disease. We and others have previously demonstrated high D-glucose induced apoptosis through the activation of the bax-caspase proteases pathway in human EC, and the potential contribution of hepatocyte growth factor as an anti-apoptotic factor for the pathogenesis of endothelial dysfunction. The anti-apoptotic action of HGF was due to bcl-2 upregulation and the phosphatidylinositol 3- kinase pathway, which is involved in Akt activation. Although it has been known for years that cardiovascular tissues can release a large amount ROS, including superoxide, hydrogen peroxide, and nitric oxide, the role of oxidative stress in atherogenesis has received increasing attention in recent years. Recent works strongly suggest that NADPH oxidase is a major source of superoxide in cardiovascular cells, and oxidative stress can be involved in the process of endothelial dysfunction. NADPH oxidase can be activated in hyperglycemia through the protein kinase C pathway. From a viewpoint of these molecular mechanisms, HMG-CoA reductase inhibitors (statins) might inhibit the high glucose-induced NADPH oxidase activation through inhibition of Rac activity and finally prevent the increase in ROS production in diabetes. Actually, recent clinical trial suggested that statins prevent several vascular events in patients with type 2 diabetes without a high concentration of LDL-cholesterol. These pleiotropic effects of statins can be expected to improve endothelial dysfunction through nitric oxide production and/or an anti-oxidant effect on diabetic patients.

Keywords: Hyperglycemia, endothelial cell, NADPH oxidase, NFkB, inflammation, cytokine