Hyperlipidemias: Cosentino F

Rydén L, Standl E, Bartnik M, Van den Berghe G, Betteridge J, de Boer MJ, Cosentino F, Jönsson B, Laakso M, Malmberg K, Priori S, Ostergren J, Tuomilehto J, Thrainsdottir I, Vanhorebeek I, Stramba-Badiale M, Lindgren P, Qiao Q, Priori SG, Blanc JJ, Budaj A, Camm J, Dean V, Deckers J, Dickstein K, Lekakis J, McGregor K, Metra M, Morais J, Osterspey A, Tamargo J, Zamorano JL, Deckers JW, Bertrand M, Charbonnel B, Erdmann E, Ferrannini E, Flyvbjerg A, Gohlke H, Juanatey JR, Graham I, Monteiro PF, Parhofer K, Pyörälä K, Raz I, Schernthaner G, Volpe M, Wood D, Anonymous00256, Anonymous00257. · Department of Cardiology, Karolinska University Hospital, Sweden. · Eur Heart J. · Pubmed #17220161 links to  free full text

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Osto E, Matter CM, Kouroedov A, Malinski T, Bachschmid M, Camici GG, Kilic U, Stallmach T, Boren J, Iliceto S, Lüscher TF, Cosentino F. · Cardiology and Cardiovascular Research, Institute of Physiology, Zurich, Switzerland. · Circulation. · Pubmed #18955669 No free full text.

Abstract: BACKGROUND: Hypercholesterolemia-induced endothelial dysfunction due to excessive production of reactive oxygen species is a major trigger of atherogenesis. The c-Jun-N-terminal kinases (JNKs) are activated by oxidative stress and play a key role in atherogenesis and inflammation. We investigated whether JNK2 deletion protects from hypercholesterolemia-induced endothelial dysfunction and oxidative stress. METHODS AND RESULTS: Male JNK2 knockout (JNK2(-/-)) and wild-type (WT) mice (8 weeks old) were fed either a high-cholesterol diet (HCD; 1.25% total cholesterol) or a normal diet for 14 weeks. Aortic lysates of WT mice fed a HCD showed an increase in JNK phosphorylation compared with WT mice fed a normal diet (P<0.05). Endothelium-dependent relaxations to acetylcholine were impaired in WT HCD mice (P<0.05 versus WT normal diet). In contrast, JNK2(-/-) HCD mice did not exhibit endothelial dysfunction (96+/-5% maximal relaxation in response to acetylcholine; P<0.05 versus WT HCD). Endothelium-independent relaxations were identical in all groups. A hypercholesterolemia-induced decrease in nitric oxide (NO) release of endothelial cells was found in WT but not in JNK2(-/-) mice. In parallel, endothelial NO synthase expression was upregulated only in JNK2(-/-) HCD animals, whereas the expression of antioxidant defense systems such as extracellular superoxide dismutase and manganese superoxide dismutase was decreased in WT but not in JNK2(-/-) HCD mice. In contrast to JNK2(-/-) mice, WT HCD displayed an increase in O(2)(-) and ONOO(-) concentrations as well as nitrotyrosine staining and peroxidation. CONCLUSIONS: JNK2 plays a critical role as a mediator of hypercholesterolemia-induced endothelial dysfunction and oxidative stress. Thus, JNK2 may provide a novel target for prevention of vascular disease and atherosclerosis.

Cosentino F, Hürlimann D, Delli Gatti C, Chenevard R, Blau N, Alp NJ, Channon KM, Eto M, Lerch P, Enseleit F, Ruschitzka F, Volpe M, Lüscher TF, Noll G. · Cardiovascular Centre, University Hospital, Rämistrasse 100, CH-8091 Zurich, Switzerland. · Heart. · Pubmed #17916662 No free full text.

Abstract: BACKGROUND: Reduced availability of tetrahydrobiopterin (BH(4)), an essential cofactor of nitric oxide (NO) synthase (NOS), decreases NO production and increases reactive oxygen species. Both mechanisms contribute to atherosclerotic vascular disease. Although acute supplementation of BH(4) improves endothelial dysfunction, the effect of chronic BH(4) in humans is unknown. OBJECTIVE: To investigate the effect of chronic BH(4) supplementation on endothelial function and oxidative stress in hypercholesterolaemia. DESIGN: Randomised double-blind, placebo-controlled trial. SETTING: University Hospital. PATIENTS: 22 hypercholesterolaemic patients (low-density lipoprotein (LDL) >4.5 mmol/l) were randomised to 4 weeks of oral BH(4) (400 mg twice daily) or placebo. Age-matched healthy volunteers served as controls. MAIN OUTCOME MEASURES: Endothelium-dependent and -independent vasodilatation was assessed by venous occlusion plethysmography. To elucidate the mechanisms of BH(4) effect, NO release and superoxide anion (O(2)(-)) production were measured in human aortic endothelial cells exposed to native LDL (2.6 mmol cholesterol/l). RESULTS: BH(4) plasma levels were significantly increased by oral supplementation. NO-mediated vasodilatation to acetylcholine was reduced in patients compared with controls and restored by BH(4). No effect of BH(4) on endothelium-independent vasodilatation was seen. Furthermore, 8-F(2 )isoprostane plasma levels, a marker of vascular oxidative stress, were reduced by BH(4). In LDL-treated endothelial cells, BH(4) levels and NO release were reduced and O(2)(-) production increased compared with control cells. Exogenous BH(4) normalised NO and O(2)(-) production. CONCLUSIONS: In hypercholesterolaemia, endothelial dysfunction and oxidative stress can be reversed by chronic oral treatment with BH(4). Thus, BH(4) availability is essential for maintaining NO synthesis and low O(2)(-) production by endothelial NOS in vivo, and may provide a rational therapeutic approach to prevent cardiovascular disease.