Dysfunction of the vascular endothelium is a hallmark of most conditions that are associated with atherosclerosis and is therefore held to be an early feature in atherogenesis. However, the mechanisms by which endothelial dysfunction occurs in smoking, dyslipidaemia, hyperhomocysteinaemia, diabetes mellitus, arterial hypertension, cerebrovascular diseases, coronary artery disease and heart failure are complex and heterogeneous. Recent data indicate that endothelial dysfunction is often associated with erectile dysfunction, which can precede and predict cardiovascular disease in men. This paper will provide a concise overview of the mechanisms causing endothelial dysfunction in the different cardiovascular risk factors and disease conditions, and of the impact of the intervention measures and treatments.

Background— Rheumatoid arthritis (RA) is associated with accelerated atherosclerosis and increased cardiovascular morbidity and mortality. Striking similarities exist in the inflammatory and immunologic response in RA and atherosclerosis. Indeed, adhesion molecules and cytokines, tumor necrosis factor (TNF)-α in particular, are key mediators of joint inflammation and of vascular dysfunction and progression of atherosclerotic vascular disease. Hence, the aim of the present study was to assess the effect of chronic antiinflammatory treatment with the anti-TNF-α antibody infliximab on disease activity and endothelial function in patients with active RA. Methods and Results— Eleven RA patients (mean age 46±5 years; disease duration 9±2 years) with high disease activity despite treatment with stable doses of methotrexate (≤25 mg/wk) and prednisone (≤10 mg/d) were investigated. Clinical status and endothelium-dependent and -independent vasodilation of the brachial artery as assessed by high-resolution ultrasound were measured before and after 12 weeks of infliximab therapy. Flow-mediated vasodilation improved from 3.2±0.4% to 4.1±0.5% ( P =0.018), whereas endothelium-independent vasodilation with nitroglycerin and baseline diameter remained unchanged (13.6±1.2% versus 12.8±1.4%, P =0.98, and 3.74±0.15 versus 3.66±0.11 mm, P =0.54, respectively). Disease activity score (DAS28) was significantly reduced, from 5.6±0.3 to 3.5±0.6 ( P =0.002). Erythrocyte sedimentation rate and C-reactive protein were lowered from 34±7 to 19±5 mm/h ( P =0.04) and from 38±11 to 15±10 mg/L ( P =0.08), respectively. Conclusions— This is the first study to show that anti-TNF-α treatment improves endothelial function in RA. The data suggest that in RA, endothelial dysfunction is part of the disease process and is mediated by TNF-α.

Background-Hypercholesterolemia is a risk factor for atherosclerosis-causing endothelial dysfunction, an early event in the disease process. In contrast, high-density lipoprotein (HDL) cholesterol inversely correlates with morbidity and mortality representing a protective effect. Therefore, we investigated the effects of reconstituted HDL on endothelial function in hypercholesterolemic men. Methods and Results-Endothelium-dependent and -independent vasodilation to intraarterial acetylcholine and sodium nitroprusside (SNP), respectively, was measured by forearm venous occlusion plethysmography in healthy normo-and hypercholesterolemic men. In hypercholesterolemics, the effects of reconstituted HDL (rHDL; 80 mg/kg IV over 4 hours) on acetylcholine-and SNP-induced changes in forearm blood flow were assessed in the presence or absence of the nitric oxide (NO) synthase inhibitor L-NMMA. Hypercholesterolemics showed reduced vasodilation to acetylcholine but not to SNP compared with normocholesterolemics (PϽ0.0001). rHDL infusion increased plasma HDL cholesterol from 1.3Ϯ0.1 to 2.2Ϯ0.1 mmol/L (PϽ0.0001, nϭ18) and significantly enhanced the acetylcholine-induced increase in forearm blood flow without affecting that induced by SNP. rHDL infusion also improved flow-mediated dilation of the brachial artery (to 4.5Ϯ0.9% from 2.7Ϯ0.6%, Pϭ0.02). NO synthase inhibition prevented the improvement in acetylcholine-induced vasodilation while leaving the response to SNP unchanged. Albumin infusion in an equivalent protein dose had no effect on vasomotion or lipid levels. Conclusions-In hypercholesterolemic patients, intravenous rHDL infusion rapidly normalizes endotheliumdependent vasodilation by increasing NO bioavailability. This may in part explain the protective effect of HDL from coronary heart disease and illustrates the potential therapeutic benefit of increasing HDL in patients at risk from atherosclerosis.

Background— There is an ongoing debate as to whether the gastrointestinal safety of COX-2 inhibition compared with nonsteroidal antiinflammatory drugs (NSAIDs) may come at the cost of increased cardiovascular events. In view of the large number of patients at cardiovascular risk requiring chronic analgesic therapy with COX-2 inhibitors for arthritic and other inflammatory conditions, the effects of selective COX-2 inhibition on clinically useful surrogates for cardiovascular disease, particularly endothelial function, need to be determined. Methods and Results— Fourteen male patients (mean age, 66±3 years) with severe coronary artery disease (average of 2.6 vessels with stenosis >75%) undergoing stable background therapy with aspirin and statins were included. The patients received celecoxib (200 mg BID) or placebo for a duration of 2 weeks in a double-blind, placebo-controlled, crossover fashion. After each treatment period, flow-mediated dilation of the brachial artery, high-sensitivity C-reactive protein, oxidized LDL, and prostaglandins were measured. Celecoxib significantly improved endothelium-dependent vasodilation compared with placebo (3.3±0.4% versus 2.0±0.5%, P =0.026), whereas endothelium-independent vasodilation, as assessed by nitroglycerin, remained unchanged (9.0±1.6% versus 9.5±1.3%, P =0.75). High-sensitivity C-reactive protein was significantly lower after celecoxib (1.3±0.4 mg/L) than after placebo (1.8±0.5 mg/L, P =0.019), as was oxidized LDL (43.6±2.4 versus 47.6±2.6 U/L, P =0.028), whereas prostaglandins did not change. Conclusions— This is the first study to demonstrate that selective COX-2 inhibition improves endothelium-dependent vasodilation and reduces low-grade chronic inflammation and oxidative stress in coronary artery disease. Thus, selective COX-2 inhibition holds the potential to beneficially impact outcome in patients with cardiovascular disease.

Background — Mental stress is a risk factor for atherosclerosis and may precipitate myocardial ischemia and infarction. Because endothelial dysfunction is an early manifestation of atherosclerosis, we investigated the impact of mental stress on endothelial function. Methods and Results — The effects of a 3-minute mental stress task on endothelium-dependent vasodilation were studied in healthy subjects without cardiovascular risk factors. Flow-mediated (FMD) and nitroglycerin (0.4 mg sublingual)-induced vasodilation were studied before and after mental stress by high-resolution ultrasound of the radial artery. Additionally, FMD was assessed before and 10 to 45 minutes after mental stress during intraarterial infusion of a selective endothelin A receptor antagonist (BQ-123, 1 nmol/min) or saline, respectively. Endothelium-dependent vasodilation was reduced by half for about 45 minutes (8.0±1.1% versus 4.1±1.0%; P <0.002), whereas endothelium-independent vasodilation to nitroglycerin remained unaffected (15.6±1.6 versus 14.3±1.3%; NS). Intraarterial infusion of BQ-123, a selective endothelin-A receptor antagonist, but not saline prevented the impairment of endothelium-dependent vasodilation (8.6±1.2 versus 9.4±1.3%; NS). In contrast, intraarterial infusion of norepinephrine of similar duration as mental stress did not inhibit FMD. Conclusions — Mental stress induces prolonged endothelial dysfunction, which is prevented by selective endothelin-A receptor antagonism. This represents a novel and important link between mental stress and atherosclerotic vascular disease.