interleukin-8 and azelnidipine

Accumulating evidence suggests that inflammation as well as oxidative stress play essential roles in atherogenesis, progression of atherosclerosis, and plaque instability and rupture. Recent studies on available anti-hypertensive agents have focused on their anti-atherosclerotic effects over and above their blood pressure lowering action. These studies have included investigations on several types of calcium channel blockers, with several investigations indicating that a dihydropiridine-based calcium channel blocker, azelnidipine, developed in Japan, has unique anti-oxidative properties. An anti-inflammatory effect of azelnidipine has, however, yet to be established and therefore we carried out a series of in vivo and in vitro studies to investigate this possibility. This was achieved by measuring inflammatory and oxidative stress markers in 16 high risk hypertensive patients administered 16mg/day of azelnidipine. After 4 weeks of treatment, serum levels of hsCRP, IL-6, and IL-8 and urinary 8-OHdG were decreased significantly, despite blood pressure remaining unchanged. Cultures of human mononuclear leukocytes collected from six healthy volunteers showed 100 nM of azelnidipine caused significant inhibition of formyl-methyonyl leucyl phenylalanine (fMLP)-induced production of IL-8. Taken together, these results suggest that azelnidipine has anti-inflammatory effects independent of its anti-hypertensive action. As leukocytes do not possess voltage-operated calcium channels, the effect of azelnidipine in these cells appears to occur independently of an L-type calcium channel antagonizing effect.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Aged, 80 and over; Anti-Inflammatory Agents, Non-Steroidal; Atherosclerosis; Azetidinecarboxylic Acid; Biomarkers; C-Reactive Protein; Calcium Channel Blockers; Deoxyguanosine; Dihydropyridines; Female; Humans; Hypertension; In Vitro Techniques; Inflammation Mediators; Interleukin-6; Interleukin-8; Leukocytes, Mononuclear; Male; Middle Aged; Oxidative Stress

Insulin resistance and central obesity are often associated with hypertension. The metabolic syndrome is a cluster of these common clinical disorders, and is related with an increased risk for cardiovascular diseases. A number of pro-inflammatory cytokines derived from adipose tissues have been thought to contribute to the development of insulin resistance and accelerated atherosclerosis. Among them, TNF-alpha has been most widely studied; it not only suppresses the insulin signaling, but also elicits vascular inflammation. Indeed, inhibition of TNF-alpha was found to improve insulin resistance in obese rats and reduce the progression of atherosclerosis in apolipoprotein E knockout mice, respectively. These observations demonstrate that TNF-alpha could play a central role in the pathogenesis of insulin resistance and accelerated atherosclerosis in the metabolic syndrome. Considering that the primary goals of treatment for hypertensive patients with the metabolic syndrome are prevention of the development of diabetes and cardiovascular events, anti-hypertensive drugs that have abilities to block the TNF-alpha signaling would be desirable as a first-line therapy for these patients. In the process of the search for such a unique anti-hypertensive drug, we have recently found that azelnidipine, a newly developed and commercially used long-acting dihydropyridine-based calcium antagonist (DHP), inhibited TNF-alpha-induced activator protein-1 activation and interleukin-8 expression in human umbilical vein endothelial cells by suppressing NADPH oxidase-mediated reactive oxygen species generation. The concentration of azelnidipine that was found effective in these in vitro-experiments is well within the therapeutic range. Since endothelial cells do not possess voltage-operated L-type calcium channels, these observations suggest that the beneficial effects of azelnidipine are not likely due to calcium channel blocking property, but due to its unique anti-oxidative ability. Furthermore, we have very recently found that serum levels of monocyte chemoattractant protein-1, a biomarker for subclinical atherosclerosis, were significantly decreased by the treatment of azelnidipine in patients with essential hypertension. In this paper, we would like to hypothesize that due to its unique TNF-alpha signal modulatory, anti-oxidative property, azelnidipine may be a promising DHP that targets diabetes and cardiovascular diseases in hypertensive patients with the metabolic synd

Topics: Antihypertensive Agents; Antioxidants; Arteriosclerosis; Azetidinecarboxylic Acid; Biomarkers; Calcium; Cardiovascular Diseases; Cells, Cultured; Chemokine CCL2; Diabetes Mellitus; Dihydropyridines; Endothelium, Vascular; Humans; Hypertension; Insulin Resistance; Interleukin-8; Models, Biological; Reactive Oxygen Species; Transcription Factor AP-1; Tumor Necrosis Factor-alpha; Umbilical Veins

Interleukin-8 (IL-8), a member of CXC chemokine family, has been found to play an important role in the pathogenesis of atherosclerosis. Tumor necrosis factor-alpha (TNF-alpha) is involved in the development and progression of atherosclerosis as well. In this study, we investigated whether and how azelnidipine, a newly developed long-acting calcium antagonist, could inhibit TNF-alpha-induced IL-8 expression in human umbilical vein endothelial cells (HUVEC). TNF-alpha significantly increased intracellular reactive oxygen species (ROS) generation in HUVEC, which was completely blocked by azelnidipine or apocynin, an inhibitor of NADPH oxidase. Azelnidipine also completely prevented TNF-alpha-induced increase in NADPH oxidase activity in HUVEC. Further, azelnidipine was found to significantly inhibit activator protein-1 (AP-1) promoter activity and IL-8 expression in TNF-alpha-exposed HUVEC. An inhibitor of AP-1, curcumin, or an anti-oxidant, N-acetylcysteine, also inhibited the TNF-alpha-induced IL-8 expression in HUVEC. These results demonstrated that azelnidipine inhibited TNF-alpha-induced IL-8 expression in HUVEC by blocking NADPH oxidase-mediated ROS generation and subsequent AP-1 activation. Our present study suggests that azelnidipine may play a protective role in the development and progression of atherosclerosis through its anti-oxidative properties.

Topics: Amlodipine; Antioxidants; Azetidinecarboxylic Acid; Calcium Channel Blockers; Dihydropyridines; Endothelium, Vascular; Humans; In Vitro Techniques; Interleukin-8; Radioligand Assay; Reactive Oxygen Species; Reverse Transcriptase Polymerase Chain Reaction; Transcription Factor AP-1; Tumor Necrosis Factor-alpha; Umbilical Veins