Ingrid Avalos

High prevalence of the metabolic syndrome in patients with systemic lupus erythematosus: association with disease characteristics and cardiovascular risk factors

Background: The metabolic syndrome is an independent risk factor for ischaemic heart disease. Patients with systemic lupus erythematosus (SLE) have accelerated atherosclerosis; however, there are no controlled studies of the metabolic syndrome in patients with SLE. Objective: To compare the prevalence of the metabolic syndrome in patients with SLE and controls and to evaluate its relationship to other cardiovascular risk factors and inflammation. Methods: 102 patients with SLE and 101 controls were studied. The prevalence of the metabolic syndrome was compared in patients and controls using the National Cholesterol Education Program Adult Treatment Panel III (NCEP) and the World Health Organization (WHO) definitions, and associations with cardiovascular risk factors and lupus characteristics were examined. Results: The metabolic syndrome was present in 32.4% of patients and in 10.9% of controls subjects (p<0.001) using the WHO definition that requires direct determination of insulin resistance, and in 29.4% of patients with SLE and in 19.8% of controls (p = 0.14) using the NCEP definition. Among patients with SLE, both definitions were significantly associated with higher concentrations of C reactive protein (p = 0.001) and the NCEP definition was significantly associated with higher concentrations of homocysteine (p<0.001), lipoprotein (a) (p = 0.02) and cholesterol (p = 0.04). Neither lupus disease activity nor damage scores were associated with the metabolic syndrome. Conclusions: Patients with SLE have a higher prevalence of insulin resistance and consequently of the WHO-defined metabolic syndrome than controls. In patients with SLE, the metabolic syndrome was associated with higher levels of inflammation and may provide a link between inflammation and increased cardiovascular risk.

Inflammation-Associated Insulin Resistance: Differential Effects in Rheumatoid Arthritis and Systemic Lupus Erythematosus Define Potential Mechanisms

OBJECTIVE Insulin resistance is increased by inflammation, but the mechanisms are unclear. The present study was undertaken to test the hypothesis that decreased insulin sensitivity is differentially associated with mediators of inflammation by studying 2 chronic inflammatory diseases of different pathogenesis, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). METHODS We measured fasting insulin, glucose, and lipid levels, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), and coronary artery calcification in 103 patients with SLE and in 124 patients with RA. Insulin sensitivity was measured using the homeostasis model assessment (HOMA) index. RESULTS The HOMA value was higher in RA patients (median 2.05 [interquartile range (IQR) 1.05-3.54]) than in SLE patients (1.40 [0.78-2.59]) (P = 0.007). CRP and ESR did not differ significantly in RA and SLE patients. Body mass index (BMI) was significantly correlated with the HOMA index in both RA (rho = 0.20) and SLE (rho = 0.54), independently of age, sex, race, and current use of corticosteroids. In RA patients, the HOMA index was also significantly positively correlated with IL-6 (rho = 0.63), TNFalpha (rho = 0.50), CRP (rho = 0.29), ESR (rho = 0.26), coronary calcification (rho = 0.26), and Disease Activity Score in 28 joints (rho = 0.21); associations adjusted for age, sex, race, BMI, and current use of corticosteroids remained significant (P < 0.05). In SLE patients, the HOMA index was also significantly correlated with ESR (rho = 0.35) and CRP (rho = 0.25), but not with other variables. The association between the ESR and the HOMA value in patients with SLE remained significant after adjustment for confounding covariates (P = 0.008). In multivariable models, the major contributing factors to the HOMA index were the BMI in SLE patients, and IL-6 and TNFalpha levels in RA patients. CONCLUSION The pathogenesis of insulin resistance and its contribution to atherogenesis varies in different inflammatory settings.

Utility of the Framingham risk score to predict the presence of coronary atherosclerosis in patients with rheumatoid arthritis

The prevalence of ischemic heart disease and atherosclerosis is increased in patients with rheumatoid arthritis (RA). In the general population, but not in patients with systemic lupus erythematosus, the Framingham risk score identifies patients at increased cardiovascular risk and helps determine the need for preventive interventions. We examined the hypothesis that the Framingham score is increased and associated with coronary-artery atherosclerosis in patients with RA. The Framingham score and the 10-year cardiovascular risk were compared among 155 patients with RA (89 with early disease, 66 with long-standing disease) and 85 control subjects. The presence of coronary-artery calcification was determined by electron-beam computed tomography. The Framingham score was compared in patients with RA and control subjects, and the association between the risk score and coronary-artery calcification was examined in patients. Patients with long-standing RA had a higher Framingham score (14 [11 to 18]) (median [interquartile range]) compared to patients with early RA (11 [8 to 14]) or control subjects (12 [7 to 14], P < 0.001). This remained significant after adjustment for age and gender (P = 0.015). Seventy-six patients with RA had coronary calcification; their Framingham risk score was higher (14 [12 to 17]) than that of 79 patients without calcification (10 [5 to 14]) (P < 0.001). Furthermore, a higher Framingham score was associated with a higher calcium score (odds ratio [OR] = 1.20, 95% confidence interval [CI] 1.12 to 1.29, P < 0.001), and the association remained significant after adjustment for age and gender (OR = 1.15, 95% CI 1.02 to 1.29, P = 0.03). In conclusion, a higher Framingham risk score is independently associated with the presence of coronary calcification in patients with RA.

Oxidative stress in systemic lupus erythematosus: relationship to disease activity and symptoms

Oxidative stress may play a role in the pathogenesis of systemic lupus erythematosus (SLE). We examined the hypothesis that oxidative stress was associated with indices of lupus disease activity and severity of symptoms. Urinary F2 isoprostane excretion, a validated marker of oxidative stress, was measured in 95 patients with SLE and 103 healthy controls. Outcome measures included SLEDAI and SLICC scores, the modified health assessment questionnaire, the fatigue severity scale (FSS), and visual analogue scales (VAS) for fatigue, pain and overall disease activity. F2 isoprostane excretion was compared in patients and controls, and its relationship with clinical variables in SLE examined. F2 isoprostane excretion did not differ significantly among patients with lupus (2.7 ± 2.3 ng/mg Cr) and control subjects (2.2 ± 1.4 ng/mg Cr) (P = 0.70). In patients with lupus, F2 isoprostane concentrations were independently associated with higher patient reported disease activity (VAS) (OR = 1.52, P = 0.01), fatigue (FSS, OR = 1.52, P = 0.03) and lower quality of life (OR = 0.73, P = 0.05), but not with objective markers or inflammation or disease activity. In conclusion, F2 isoprostane excretion is associated with patient-reported symptoms in SLE but not with measures of inflammation, SLEDAI or SLICC. Oxidative stress may contribute to debilitating symptoms such as fatigue in SLE.

Cardiovascular risk scores and the presence of subclinical coronary artery atherosclerosis in women with systemic lupus erythematosus.

The Framingham risk score is widely used to identify patients at increased cardiovascular risk, and women with systemic lupus erythematosus (SLE) have a marked increased prevalence of cardiovascular events. Thus, we examined the hypothesis that cardiovascular risk scores would identify women with SLE who had asymptomatic coronary atherosclerosis. Ninety-three women with SLE and 65 control subjects were studied. The Framingham score and a score for younger populations developed from the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study were compared in both groups. Coronary atherosclerosis was ascertained by electron beam computed tomography. There were no significant differences in the median (interquartile range) Framingham [5 (2-10) compared to 7 (0-10), P = 0.88] and PDAY [15 (14-18) compared to 16 (13-18), P = 0.99] scores in patients with SLE and controls, respectively. Coronary atherosclerosis was associated with higher Framingham [12 (3-15) compared to 4 (1-8), P = 0.008] and PDAY [17 (15-19 compared to 15 (12-18), P = 0.03)] scores in patients with SLE; however, 99% of patients were classified as low-risk with a 10-year predicted risk of 1% (<1-3%). Our data indicate that cardiovascular risk scores are not adequate for risk stratification in women with SLE. Measurement of coronary calcification may add information to identify asymptomatic women with lupus who might benefit from aggressive preventive measures.

Atherosclerosis and inflammation : insights from rheumatoid arthritis

Cardiovascular disease is a major health care problem and the most common cause of death among individuals from developed nations. Our understanding of atherosclerosis has evolved from a passive process resulting in narrowing of the lumen and consequent myocardial ischemia to a dynamic process that involves inflammation. The study of atherosclerosis in patients with chronic inflammation, such as rheumatoid arthritis (RA), will provide insights into the relationship between inflammation and atherosclerosis. We review the relationship between atherosclerosis and inflammation within the context of RA, providing evidence that patients with RA have increased cardiovascular morbidity and mortality and accelerated coronary and extra-coronary atherosclerosis. In addition, traditional and novel cardiovascular risk factors are discussed. Finally, actions that a rheumatologist can take to better control this cardiovascular morbidity are suggested. These can be summarized as follows: (1) careful assessment and treatment of cardiovascular risk, (2) better control of inflammation, and (3) individual risk–benefit evaluation of need for cyclo-oxygenase-2 inhibitors, nonsteroidal anti-inflammatory drugs, and high doses of corticosteroids.

Amino-terminal fragment of the prohormone brain-type natriuretic peptide in rheumatoid arthritis

OBJECTIVE Increased concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP) are associated with cardiovascular morbidity and mortality, but little is known about their relationship to chronic inflammation. Patients with rheumatoid arthritis (RA) have chronic inflammation, increased arterial stiffness, and accelerated coronary atherosclerosis. This study was undertaken to test the hypothesis that NT-proBNP concentrations are elevated in patients with RA and are associated with coronary artery calcification and markers of inflammation. METHODS In 159 patients with RA (90 with early RA and 69 with longstanding RA) without heart failure and 88 control subjects, serum concentrations of NT-proBNP, interleukin-6 (IL-6), and tumor necrosis factor alpha (TNFalpha) were measured and coronary calcification was assessed. Associations between NT-proBNP levels and the other parameters were investigated. RESULTS NT-proBNP concentrations were elevated in patients with longstanding RA (median 142.8 pg/ml [interquartile range 54.8-270.5]) and those with early RA (median 58.1 pg/ml [interquartile range 19.4-157.6]) compared with controls (18.1 [3.2-46.0]) (P < 0.001). In patients with RA, NT-proBNP concentrations were associated with age (rho = 0.35, P < 0.001), levels of IL-6 (rho = 0.33, P < 0.001), TNFalpha (rho = 0.23, P = 0.003), and C-reactive protein (CRP) (rho = 0.21, P = 0.01), coronary calcium score (rho = 0.30, P < 0.001), systolic blood pressure (rho = 0.30, P < 0.001), and disease activity (rho = 0.29, P < 0.001). After adjustment for age, race, and sex, the associations between NT-proBNP concentrations and disease activity, TNFalpha, IL-6, and CRP remained significant, but those with systolic blood pressure and coronary calcium score were attenuated. CONCLUSION NT-proBNP concentrations are increased in patients with RA without clinical heart failure and may indicate subclinical cardiovascular disease and a chronic inflammatory state.

T cells and in situ cryoglobulin deposition in the pathogenesis of lupus nephritis

We discuss a 53-year-old woman with systemic lupus erythematosus who presented with vasculitis, hypocomplementemia and nephritis. Although her serum complement 4 (C4) levels were zero, she had four copies of C4 gene. Renal biopsy revealed membranoproliferative glomerulonephritis and the presence of cryoglobulins, detected by electron microscopy, and significant numbers of T cells in the interstitium. Cryoglobulins were considered responsible for the complete consumption of C4 in the serum the levels of which improved gradually after treatment. T cells in the kidney were found to express CD44 and phosphorylated ezrin/radixin/moiesin which explain why they homed to the kidney inappropriately. The contribution of cryoglobulins and T cells in the expression of kidney pathology is discussed.

Aspirin therapy and thromboxane biosynthesis in systemic lupus erythematosus

Incomplete suppression of thromboxane biosynthesis during aspirin therapy is associated with increased cardiovascular risk. Since systemic lupus erythematosus (SLE) is associated with platelet activation and increased cardiovascular mortality, we compared thromboxane and prostacyclin biosynthesis in patients with SLE and control subjects, and measured inhibition of thromboxane excretion in aspirin-treated subjects. We measured the urinary excretion of 11-dehydro thromboxane B 2 (TXB2) and 2,3-dinor 6-ketoPGF1α (PGI-M), the stable metabolites of thromboxane A2 and prostacyclin, respectively, in 74 patients with SLE and 70 controls. In subjects who were not receiving aspirin, TXB2 excretion was higher in patients with SLE [0.40 ng/mg creatinine (0.26—0.64), median (interquartile range)] than controls [0.31 ng/mg creatinine (0.23—0.44)] (P = 0.04), and in these patients, TXB2 excretion correlated with disease activity (rho = 0.28, P = 0.03) and tumor necrosis factor alpha (rho = 0.48, P < 0.001). Aspirin therapy resulted in significantly lower TXB2 excretion in controls (P = 0.01), but not in patients with SLE (P = 0.10), compared with subjects not receiving aspirin. Prostacyclin biosynthesis did not differ among patients and controls, and was not affected by aspirin (P all >0.35). Thromboxane biosynthesis is increased in SLE and is associated with disease activity. Additionally, response to aspirin may be attenuated in some patients with SLE. Lupus (2007) 16, 981—986.

Overexpression of connexin 43 reduces melanoma proliferative and metastatic capacity

Background:Alterations in connexin 43 (Cx43) expression and/or gap junction (GJ)-mediated intercellular communication are implicated in cancer pathogenesis. Herein, we have investigated the role of Cx43 in melanoma cell proliferation and apoptosis sensitivity in vitro, as well as metastatic capability and tumour growth in vivo.Methods:Connexin 43 expression levels, GJ coupling and proliferation rates were analysed in four different human melanoma cell lines. Furthermore, tumour growth and lung metastasis of high compared with low Cx43-expressing FMS cells were evaluated in vivo using a melanoma xenograft model.Results:Specific inhibition of Cx43 channel activity accelerated melanoma cell proliferation, whereas overexpression of Cx43 increased GJ coupling and reduced cell growth. Moreover, Cx43 overexpression in FMS cells increased basal and tumour necrosis factor-α-induced apoptosis and resulted in decreased melanoma tumour growth and lower number and size of metastatic foci in vivo.Conclusions:Our findings reveal an important role for Cx43 in intrinsically controlling melanoma growth, death and metastasis, and emphasise the potential use of compounds that selectively enhance Cx43 expression on melanoma in the future chemotherapy and/or immunotherapy protocols.