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Background: Recent in vitro studies suggest that inducible nitric oxide synthase (iNOS) activity mediates endothelial dysfunction. Rheumatoid arthritis (RA) is a chronic inflammatory condition and is associated with endothelial dysfunction and increased risk of cardiovascular disease. The aim of the study was to establish the contribution of iNOS to endothelial function., Methods: Forearm blood flow (FBF) was measured during intra-arterial infusions of acetylcholine (ACh), sodium nitroprusside (SNP), N(G)-monomethyl-l-arginine (l-NMMA) and aminoguanidine (AG) in 12 RA patients and 13 healthy control subjects. Levels of C-reactive protein (CRP) and myeloperoxidase (MPO) were assessed. FBF data are presented as mean percentage changes in the ratio (infused/control arm) of FBF + or - SEM., Results: FBF response to ACh was reduced in patients with RA compared to controls (179 + or - 29 v. 384 + or - 72%, respectively; P=0.01), but SNP response was not (P=0.5). FBF response to AG differed between patients and controls (-15 + or - 2% v. 13 + or - 4%, respectively; P<0.001), whereas the response to l-NMMA did not (P=0.4). In a multiple regression model log CRP, AG response and LDL were found to be independent predictors of endothelial function (R(2)=0.617, P<0.001)., Conclusion: RA patients have endothelial dysfunction and increased iNOS activity in comparison to controls. Furthermore, CRP and iNOS activity were independently associated with endothelial function. Our data demonstrates that inflammation is a key mediator in a process of endothelial dysfunction possibly via activation of iNOS and increased production of MPO.

Objectives: Our aim was to determine reproducibility of the flow-mediated dilation (FMD) response profile, and discriminatory ability of the components., Background: Brachial FMD is widely used to study conduit artery endothelial function. Automated B-mode image edge detection (B-ED) provides a full response profile. Reproducibility and biological relevance of these additional components have not been fully explored., Methods: Forty-two healthy adults underwent FMD using B-ED repeated at fixed time intervals up to 3 months. The FMD profile was assessed for diameter changes, area under the curve, and time course. Measures were compared in 25 adults with hypercholesterolemia, 25 subjects with diabetes, and 50 matched control subjects., Results: The maximum change in FMD was the most reproducible (coefficient of variation = 9.8%, 10.6%, 6.6%, and 9.2% at 4 to 6 h, 1 week, 1 month, and 3 months, respectively). Most of the variability occurred between subjects rather than within. All FMD measures except time course were significantly reduced in hypercholesterolemia and diabetes. Power curves were generated to indicate the appropriate number of subjects for parallel and crossover study designs., Conclusions: Maximum FMD percentage change from baseline is the most reproducible of the response curve measures and best identifies those with risk factors. Flow-mediated dilation measured by B-ED is robust and practical to assess the effect of interventions on endothelial function in clinical trials.

Objectives: The aim of this study was to investigate the effect of simvastatin and ezetimibe on inflammation, disease activity, endothelial dysfunction, and arterial stiffness in a cohort of rheumatoid arthritis (RA) patients., Background: Rheumatoid arthritis is a chronic inflammatory condition associated with increased cardiovascular risk. Statins reduce inflammation and disease activity in RA patients, but whether this is due to pleiotropism or cholesterol lowering per se is unclear., Methods: Twenty patients received 20 mg simvastatin or 10 mg ezetimibe each for 6 weeks in a randomized double-blind crossover study. Disease activity, blood pressure, aortic pulse wave velocity (PWV), brachial artery flow-mediated dilation (FMD), and serum inflammatory markers were measured before and after each treatment., Results: Both ezetimibe and simvastatin significantly reduced total cholesterol (-0.62 +/- 0.55 mmol/l and -1.28 +/- 0.49 mmol/l, respectively; p < 0.001), low-density lipoprotein cholesterol (-0.55 +/- 0.55 mmol/l and -1.28 +/- 0.49 mmol/l; p < 0.0001), and C-reactive protein (-5.35 +/- 9.25 mg/l and -5.05 +/- 6.30 mg/l; p < 0.001). Concomitantly, Disease Activity Score (-0.55 +/- 1.01 and -0.67 +/- 0.91; p = 0.002), aortic PWV (-0.69 +/- 1.15 m/s and -0.71 +/- 0.71 m/s; p = 0.001), and FMD (1.37 +/- 1.17% and 2.51 +/- 2.13%; p = 0.001) were significantly improved by both drugs., Conclusions: This study demonstrates that both ezetimibe and simvastatin reduce disease activity and inflammatory markers to a similar extent in patients with RA. Therapy is also associated with a concomitant reduction in aortic PWV and improvement in endothelial function. This suggests that cholesterol lowering per se has anti-inflammatory effects and improves vascular function in RA.

Isolated systolic hypertension is associated with increased cardiovascular risk. It is thought to result from large artery stiffening, which is determined by structural components within the vasculature but also by functional factors including NO and endothelin-1. We hypothesized that endothelial dysfunction would account for increased arterial stiffness in patients with isolated systolic hypertension. The aim of this study was to investigate the relationship between endothelial function and arterial stiffness in these patients along with control subjects. We studied 113 subjects: 35 patients with isolated systolic hypertension (mean age+/-SD: 68+/-6 years), 30 age-matched control subjects (65+/-5 years), and 48 young control subjects (37+/-9 years). Aortic pulse wave velocity (PWV) was derived by sequential carotid/femoral waveform recordings. Conduit artery endothelial function was determined by flow-mediated dilatation. Aortic PWV was higher (9.65+/-2.56 m/s versus 8.26+/-0.85 m/s; P=0.009), and flow-mediated dilatation was lower (2.67+/-1.64% versus 4.79+/-3.1%; P=0.03) in patients with isolated systolic hypertension compared with age-matched control subjects. Similarly, aortic PWV was also higher, and flow-mediated dilatation lower, in older versus young control subjects (8.26+/-0.85 m/s versus 7.09+/-1.01 m/s and 4.79+/-3.1% versus 6.94+/-2.7%; P=0.004 for both). Overall, aortic PWV correlated inversely with flow-mediated dilatation (r=-0.3; P=0.001), which remained significant after adjustment for confounding factors (P=0.01). Patients with isolated systolic hypertension have higher aortic PWV and decreased endothelial function compared with age-matched control subjects. Our results suggest that endothelial function contributes significantly to increased arterial stiffness in patients with isolated systolic hypertension and with age.