Arterial wave reflection and subclinical atherosclerosis in rheumatoid arthritis

OBJECTIVES

Atherosclerotic cardiovascular disease risk is increased in rheumatoid arthritis (RA). Wave reflection occurs at arterial branching points, which are particularly prone to atherosclerosis. We explored the relationship of wave reflection with atherosclerosis in RA.

METHODS

One hundred and sixty three RA patients (110 white, 31 Asian, 17 black and 5 of mixed ancestry) without cardiovascular disease participated. Arterial stiffness, wave reflection, pressure pulsatility, plaque in the extracranial carotid artery tree and the mean of the left and right common carotid arteries intima-thickness were determined. Associations were identified in multivariable regression models.

RESULTS

One SD increase in reflected wave pressure (OR (95% CI) = 2.54 (1.41-4.44), p=0.001), reflection magnitude (OR (95% CI) = 1.84 (1.17-2.89), p=0.008), central pulse pressure (OR (95% CI) = 1.89 (1.12-3.22), p=0.02) and peripheral pulse pressure (OR (95% CI) = 2.09 (1.23-3.57), p=0.007) were associated with plaque. The association of wave reflection with plaque was independent of arterial stiffness and pressure pulsatility, and was present in both hypertensive and normotensive RA patients. In receiver operator characteristic curve analysis, the optimal cutoff value for reflected wave pressure in predicting plaque presence was 25 mmHg with a sensitivity, specificity, positive predictive value and negative predictive value of 45.2%, 89.3%, 78.6% and 66.2%, respectively; a reflected wave pressure of >25 mmHg was associated with plaque in univariate and adjusted analysis (p<0.0001 for both). Arterial function was not independently related to carotid intima-media thickness.

CONCLUSIONS

Consideration and therapeutic targeting of wave reflection may improve cardiovascular disease prevention in RA.

Nesfatin-1 and visfatin expression is associated with reduced atherosclerotic disease risk in patients with rheumatoid arthritis

Nesfatin is an anti-inflammatory molecule that reduces atherosclerotic cardiovascular risk. By contrast, visfatin has pro-inflammatory properties and is pro-atherogenic. We examined the potential impact of nesfatin and visfatin on atherosclerotic disease in 232 (113 black and 119 white) consecutive rheumatoid arthritis (RA) patients from 2 centers. Independent relationships of nesfatin and visfatin concentrations with metabolic risk factors, endothelial activation, carotid atherosclerosis and altered plaque stability were determined in multivariable regression models. Rheumatoid factor (RF) positivity was associated with both nesfatin (β = 0.650, p < 0.0001) and visfatin levels (β = 0.157, p = 0.03). Visfatin concentrations were related to increased diastolic blood pressure (β = 4.536, p = 0.01) and diabetes prevalence (β = 0.092, p = 0.04). Nesfatin levels were associated with reduced carotid intima-media thickness (β = -0.017, p = 0.008). Nesfatin (β = 0.116, p = 0.001) and visfatin concentrations (β = 0.234, p = 0.001) were related to those of matrix metalloproteinase-2 (MMP-2), a plaque stability mediator. Nesfatin and visfatin concentrations were directly correlated (Spearman's rho = 0.516). The nesfatin-MMP-2 and visfatin-MMP-2 relations were both stronger in RF negative compared to RF positive patients (interaction p = 0.01 and p = 0.04, respectively). Nesfatin is associated with reduced atherosclerosis and increased plaque stability mediator levels in RA. Visfatin is related to adverse cardio-metabolic risk in RA. Increased MMP-2 expression in relation to visfatin may represent a compensatory mechanism aimed at reducing cardiovascular risk in RA.

Cardiovascular Risk Factors and Disease Characteristics Are Consistently Associated with Arterial Function in Rheumatoid Arthritis

Objective.

Arterial properties influence cardiovascular disease (CVD) risk. We identified potential determinants of arterial function in patients with rheumatoid arthritis (RA).

Methods.

Relationships of traditional cardiovascular risk factors and RA characteristics with arterial stiffness (pulse wave velocity), wave reflection (augmentation index, reflected wave pressure, and reflection magnitude), and pressure pulsatility (central systolic and pulse pressure, peripheral pulse pressure, pulse pressure amplification, and forward wave pressure) were identified in multivariable backward regression models among 177 patients without established CVD (118 white, 32 Asian, 22 black, 5 mixed ancestry).

Results.

Recorded characteristics explained 37% (pulse wave velocity) to 71% (reflected wave pressure) of the variability in arterial function. These factors were particularly associated with wave reflection and pressure pulsatility: RA duration (p = 0.04), rheumatoid factor status (p = 0.01 to 0.03), leukocyte counts (p = 0.02 to 0.05), and total cholesterol (p < 0.01 to 0.03). Body mass index (p < 0.01 to 0.02) and insulin resistance (p < 0.01 to 0.01) were related to reduced wave reflection and peripheral pulse pressure. Exercise (p = 0.02) and alcohol consumption (p < 0.01) were associated with increased pulse pressure amplification and decreased peripheral pulse pressure, respectively. Tumor necrosis factor-α inhibition (p < 0.01) was related to reduced pulse wave velocity, and tetracycline use (p = 0.02) to decreased peripheral pulse pressure.

Conclusion.

Traditional cardiovascular risk factors and disease characteristics are consistently associated with vascular hemodynamic alterations in RA. The relative effect of arterial stiffness, wave reflection, and pressure pulsatility on CVD risk in RA needs further study.

Complete suppression of neoclassical tearing modes with current drive at the electron-cyclotron-resonance frequency in ASDEX upgrade tokamak

Noninductive current drive has been performed in the tokamak ASDEX upgrade by injection of radiofrequency waves at the second harmonic of the electron-cyclotron frequency in order to suppress unwanted disturbances of the magnetic-field configuration. The current has been driven parallel [co-electron cyclotron current drive (ECCD)] and antiparallel (counter-ECCD) to the plasma current to compare the effect of heating with direct current drive in the magnetic island. For the first time it has been shown experimentally that total stabilization of neoclassical tearing modes is possible with co-ECCD. The experiments verify the role of direct current drive as opposed to local heating.

Simultaneous attainment of high electron and ion temperatures in discharges with internal transport barriers in ASDEX upgrade

Internal transport barriers have been demonstrated to exist also under conditions with T(e) approximately T(i) approximately 10 keV and predominant electron heating of the tokamak core region. Central electron cyclotron heating was added to neutral beam injection-heated ASDEX Upgrade discharges with a preexisting internal transport barrier, established through programmed current ramping leading to shear reversal. Compared to a reference internal transport barrier discharge without electron cyclotron resonance heating, the electron heat conductivity in the barrier region was found not to increase, in spite of a fivefold increase in electron heat flux, and also angular momentum and ion energy transport did not deteriorate.

Atypical endogenous opioid systems in mice in relation to an auto-addiction opioid model of anorexia nervosa

We have proposed that the atypical opioid system in the mouse may be representative of that in the anorexia nervosa patient and may account for a biological predisposition to the disorder. This is in the context of our auto-addiction model of anorexia nervosa in which endogenous opioids play a critical role in its etiology. Morphine activation of the endogenous opioid systems increases food intake and causes sedation in most species, including normal humans and rats. In contrast in BALB/C mice, morphine causes anorexia and hyperactivity, which we suggest may be true in the anorexia nervosa patient. A variety of atypical opioid systems have been demonstrated in different mouse strains, based on other responses. The present study examines these strains with reference to the responses relevant to our anorexia nervosa model. Three patterns are described--anorexia with hyperactivity (BALB/C and C57BL/6J mice), anorexia without hyperactivity (DBA/J mice), and a biphasic curve with hyperphagia at low doses and anorexia and hyperactivity at higher doses (CF-1 mice). Only female mice were used. These atypical opioid systems may reflect a spectrum of biological predispositions to the disorder. These strain differences may also provide useful correlations of the genetic determinants of various opiate responses and provide useful comparisons in characterizing the essential features responsible for the atypical responses.