Evidence for peripheral impaired glucose handling in patients with connective tissue diseases

Hydroxychloroquine and Cardiovascular Events in Patients with Rheumatoid Arthritis

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of mortality in patients with rheumatoid arthritis (RA). Some studies have reported a decrease in CVD in patients with RA using hydroxychloroquine (HCQ). Most of these have had fewer participants and have analyzed only composite outcomes. We aimed to identify the association between the use of HCQ in patients with RA and the incidence of major adverse cardiac events (MACEs), cerebral infarction, and AMI.

METHODS

This was a retrospective observational study using the TriNetX Diamond Network. Propensity score matching (PSM) was used to equilibrate the cohorts. The dependent variables in our study were MACE, cerebral infarction, and AMI.

RESULTS

A total of 2,261,643 patients with RA were identified. Approximately 6% had been prescribed HCQ. Of those prescribed HCQ, 80% (112,743) were females, while of those not prescribed HCQ, 72.5% (1,536,937) were females. HCQ was associated with lower rates of MACE (HR 0.827, 95%CI 0.8,0.86), cerebral infarction (HR 0.824, 95% CI 0.78,0.87), and AMI (HR 0.9, 95% CI 0.85,0.96). These associations were not seen in patients taking biologics. HCQ was associated with lower MACE in all other subgroups.

CONCLUSION

In conclusion, HCQ was slightly beneficial in decreasing MACE and cerebral infarction in patients with RA. These associations were significantly lower in patients taking methotrexate or biologics. Although there was a significant decrease in the risk of AMI in all patients with RA, these results were not replicated in subgroup analyses, and there was an apparent increased risk of AMI with the use of HCQ in patients using biologics.

Endothelial function and endothelial progenitor cells in systemic lupus erythematosus

The observations that traditional cardiovascular disease (CVD) risk factors fail to fully account for the excessive cardiovascular mortality in patients with systemic lupus erythematosus (SLE) compared with the general population have prompted in-depth investigations of non-traditional, SLE-related risk factors that contribute to cardiovascular complications in patients with SLE. Of the various perturbations of vascular physiology, endothelial dysfunction, which is believed to occur in the earliest step of atherosclerosis, has been extensively investigated for its contribution to CVD risk in SLE. Endothelial progenitor cells (EPCs), which play a crucial part in vascular repair, neovascularization and maintenance of endothelial function, are quantitatively and functionally reduced in patients with SLE. Yet, the lack of a unified definition of EPCs, standardization of the quantity and functional assessment of EPCs as well as endothelial function measurement pose challenges to the translation of endothelial function measurements and EPC levels into prognostic markers for CVD in patients with SLE. This Review discusses factors that contribute to CVD in SLE, with particular focus on how endothelial function and EPCs are evaluated currently, and how EPCs are quantitatively and functionally altered in patients with SLE. Potential strategies for the use of endothelial function measurements and EPC quantification as prognostic markers of CVD in patients with SLE, and the limitations of their prognostication potential, are also discussed.

Targeting Inflammatory Cytokines to Improve Type 2 Diabetes Control

Type 2 diabetes (T2D) is one of the most common chronic metabolic disorders in adulthood worldwide, whose pathophysiology includes an abnormal immune response accompanied by cytokine dysregulation and inflammation. As the T2D-related inflammation and its progression were associated with the balance between pro and anti-inflammatory cytokines, anticytokine treatments might represent an additional therapeutic option for T2D patients. This review focuses on existing evidence for antihyperglycemic properties of disease-modifying antirheumatic drugs (DMARDs) and anticytokine agents (anti-TNF-α, anti-interleukin-(IL-) 6, -IL-1, -IL-17, -IL-23, etc.). Emphasis is placed on their molecular mechanisms and on the biological rationale for clinical use. Finally, we briefly summarize the results from experimental model studies and promising clinical trials about the potential of anticytokine therapies in T2D, discussing the effects of these drugs on systemic and islet inflammation, beta-cell function, insulin secretion, and insulin sensitivity.

Cardiovascular Risk in Rheumatoid Arthritis: Literature Review

Rheumatoid arthritis (RA) is the most common inflammatory arthritis disease with a worldwide prevalence of 1-3%. RA patients are at higher risk of atherosclerosis than their matched age-sex controls. Cardiovascular diseases (CVDs) account for a 50% risk of increased mortality and morbidity in RA. The pattern of CVD in RA patients differs from that in the general population; RA patients are more likely to have silent ischemic heart disease, sudden death, heart failure, and die early. RA patients tend to have a 5-10 years reduction in their life span than their matched healthy population. Traditional (classical) CV risk factors work separately or synergistically with the underlying inflammation to increase CVD risk in RA. Moreover, inflammation is defined as an independent CVD risk factor. This literature review aims to discuss the traditional CVD risk factors and their association with inflammation in RA.

Impact of disease activity on impaired glucose metabolism in patients with rheumatoid arthritis

Objective

To explore glucose metabolism in rheumatoid arthritis (RA) and its association with insulin resistance (IR) risk factors and disease activity indicators, including matrix metalloproteinase-3 (MMP3).

Methods

This single-center study included 127 non-diabetic subjects: 90 RA patients and 37 matched controls. IR-related risk factors, disease activity (DAS28-ESR/CRP), concentrations of inflammation markers, MMP3, glucose, specific insulin, and C-peptide (a marker of β-cell secretion) were determined. Homeostasis Model Assessment was used to establish insulin resistance (HOMA2-IR) and sensitivity (HOMA2-%S). Associations of HOMA2 indices with IR-related risk factors, inflammation markers, and RA activity were tested using multiple regression analyses.

Results

RA patients had significantly increased HOMA2-IR index than controls. In the RA group, multivariate analysis revealed DAS28-ESR, DAS28-CRP, tender joint counts, patient’s global assessment, and MMP3 level as significant positive predictors for HOMA2-IR (β = 0.206, P = 0.014; β = 0.192, P = 0.009; β = 0.121, P = 0.005; β = 0.148, P = 0.007; β = 0.075, P = 0.025, respectively), and reciprocal negative for HOMA2-%S index. According to the value of the coefficient of determination (R²), DAS28-ESR ≥ 5.1 has the largest proportion of variation in both HOMA2-IR indices. DAS28-ESR ≥ 5.1 and ESR were independent predictors for increased C-peptide concentration (β = 0.090, P = 0.022; β = 0.133, P = 0.022). Despite comparability regarding all IR-related risk factors, patients with DAS28-ESR ≥ 5.1 had higher HOMA2-IR than controls [1.7 (1.2–2.5) vs. 1.2 (0.8–1.4), P = 0.000]. There was no difference between patients with DAS28-ESR < 5.1 and controls [1.3 (0.9–1.9) vs. 1.2 (0.8–1.4), P = 0.375].

Conclusions

RA activity is an independent risk factor for impaired glucose metabolism. DAS28-ESR ≥ 5.1 was the main contributor to this metabolic disturbance, followed by MMP3 concentration, outweighing the impact of classic IR-related risk factors.

Asymmetric Dimethyl Arginine as a Biomarker of Atherosclerosis in Rheumatoid Arthritis

Cardiovascular disease is the main cause of morbidity and mortality in rheumatoid arthritis (RA). Despite the advent on new drugs targeting the articular manifestations, the burden of cardiovascular disease is still an unmet need in the management of RA. The pathophysiology of accelerated atherosclerosis associated to RA is not yet fully understood, and reliable and specific markers of early cardiovascular involvement are still lacking. Asymmetric dimethylarginine is gaining attention for its implication in the pathogenesis of endothelial dysfunction and as biomarkers of subclinical atherosclerosis. Moreover, the metabolic pathway of methylarginines offers possible targets for therapeutic interventions to decrease the cardiovascular risk. The purpose of this review is to describe the main causes of increased methylarginine levels in RA, their implication in accelerated atherosclerosis, the possible role as biomarkers of cardiovascular risk, and finally the available data on current pharmacological treatment.

Energy expenditure and nutritional complications of metabolic syndrome and rheumatoid cachexia in rheumatoid arthritis: an observational study using calorimetry and actimetry

OBJECTIVE

Altered energy expenditure may contribute to the nutritional complications of RA, metabolic syndrome (MS) and rheumatoid cachexia (RC). The main aim of this study was to evaluate whether the altered resting energy expenditure (REE) and physical activity (PA)-related energy expenditure (EE) are related to the duration of RA and inflammatory activity and nutritional complications in RA.

METHODS

Among patients with well-characterized RA (duration, activity: DAS28 ESR), we measured REE by indirect calorimetry, and PA-EE by actimetry (SenseWear Armband). MS was defined according to the International Diabetes Federation criteria and RC from DXA body composition analysis. The relations between the characteristics and nutritional complications, and EE were analysed by linear regression.

RESULTS

Fifty-seven patients were included [73% women, age 57 (10) years] with a wide range of disease duration: 3.8 (3.0) years, and DAS28 ESR: 3.9 (1.4). The mean REE was 1486 (256) kcal/day, associated with the DAS28 ESR (β = +0.21, P = 0.02 after adjusting for gender and fat free mass). The prevalence of MS and RC was, respectively, 24 and 18%, and they were unrelated to each other. The patients with MS and/or RC had double the longstanding RA score (P < 0.05), twice the homeostasis model assessment of insulin resistance values (P = 0.052) and halved levels of PA (P < 0.05 for metabolic equivalent tasks (METs) and number of steps/day). Two modifiable factors were associated with the presence of MS and/or RC: a low level of PA as METs [exp(B) = 0.03, P = 0.009] and the use of glucocorticoids [exp(B) = 4.08, P = 0.046].

CONCLUSION

Low levels of PA and treatment by glucocorticoids are associated with the nutritional complications of RA, suggesting the potential for therapeutic interventions.

Effects of Tumour Necrosis Factor Antagonists on Insulin Sensitivity/Resistance in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

Beyond the joints, TNFi (tumour necrosis factor inhibitor) therapy may confer systemic benefits in rheumatoid arthritis (RA). Several studies have investigated the role of TNFi on insulin resistance/sensitivity (IR/IS). This question is of general interest given the emerging evidence linking inflammation and insulin resistance. The main aim of this review was to summarise the published data and to determine the effects of TNFi on IR/IS.

METHODS

We searched the PubMed and ISI Web of Knowledge databases for studies which examined the effects of TNFi on IR/IS. The studies were assessed independently by two reviewers according to a pre-specified protocol. The data on Homeostatic Model Assessment for Insulin resistance (HOMA) and Quantitative Insulin Sensitivity Check Index (QUICKI) were pooled and reported as standard difference in means (SDM) with 95% confidence interval (CI) using a random-effects model.

RESULTS

A total of eight studies with 260 subjects met the selection criteria. The duration of the studies was from 8 weeks to 12 months. There was statistically significant reduction in HOMA index in six out of eight studies and four reported significant increment in QUICKI. The pooled analysis revealed significant reduction in HOMA [SDM-0.148, 95%CI[-0.278 to -0.017], p=0.026] and increment in QUICKI [SDM 0.312, 95%CI[0.019 to 0.606], p=0.037] with TNFi.

CONCLUSION

There is emerging evidence to support that TNFi therapy improves IS and reduces IR in RA. Further, well conducted trials are needed to determine if such effects translate to lower incidence of diabetes in RA or other autoimmune conditions on biologic therapy.

Adipose depots, not disease-related factors, account for skeletal muscle insulin sensitivity in established and treated rheumatoid arthritis

OBJECTIVE

In prior reports, individuals with rheumatoid arthritis (RA) exhibited increased insulin resistance. However, those studies were limited by either suboptimal assessment methods for insulin sensitivity or a failure to account for important determinants such as adiposity and lack of physical activity. Our objectives were to carefully assess, compare, and determine predictors of skeletal muscle insulin sensitivity in RA, accounting for adiposity and physical activity.

METHODS

Thirty-nine individuals with established (seropositive or erosions) and treated RA and 39 controls matched for age, sex, race, body mass index, and physical activity underwent a frequently sampled intravenous glucose tolerance test to determine insulin sensitivity. Inflammation, body composition, and physical activity were assessed with systemic cytokine measurements, computed tomography scans, and accelerometry, respectively. Exclusions were diabetes, cardiovascular disease, medication changes within 3 months, and prednisone use over 5 mg/day. This investigation was powered to detect a clinically significant, moderate effect size for insulin sensitivity difference.

RESULTS

Despite elevated systemic inflammation [interleukin (IL)-6, IL-18, tumor necrosis factor-α; p < 0.05 for all], persons with RA were not less insulin sensitive [SI geometric mean (SD): RA 4.0 (2.4) vs control 4.9 (2.1)*10(-5) min(-1)/(pmol/l); p = 0.39]. Except for visceral adiposity being slightly greater in controls (p = 0.03), there were no differences in body composition or physical activity. Lower insulin sensitivity was independently associated with increased abdominal and thigh adiposity, but not with cytokines, disease activity, duration, disability, or disease-modifying medication use.

CONCLUSION

In established and treated RA, traditional risk factors, specifically excess adiposity, play more of a role in predicting skeletal muscle insulin sensitivity than do systemic inflammation or other disease-related factors.

Chronic inflammation and low-dose glucocorticoid effects on glucose metabolism in premenopausal females with rheumatoid arthritis free of conventional metabolic risk factors

Chronic systemic inflammation is associated with increased cardiovascular mortality in patients with rheumatoid arthritis (RA). The aim of our study was to investigate association of glucose metabolism and inflammatory markers in a group of patients with rheumatoid arthritis free of other metabolic risk factors. Twenty-two premenopausal RA females (11 patients on low-dose GC (<8.5 mg/day of prednisone or equivalent), 11 patients without glucocorticoid therapy) and 15 age- and BMI-matched healthy females underwent the oral glucose tolerance test. The insulin sensitivity indices according Matsuda (ISI(MAT)) and Cederholm (ISI(CED)) as well as HOMA2 %S were calculated. Cytokines, lipid profile, non-esterified fatty acids (NEFA) and plasminogen activator inhibitor-1 (PAI-1) were measured in baseline blood samples. Despite elevated interleukin IL-6 and TNF alpha, glucose, insulin and C-peptide responses to oral glucose load as well as ISI(MAT), ISI(CED), PAI-1 and NEFA were comparable in both RA groups and healthy controls. HOMA2 %S correlated with disease activity. In conclusions, low-dose glucocorticoid treatment does not lead to glucose metabolism impairment in RA patients without other metabolic risk factors. Increased cardiovascular mortality and morbidity is probably due to a direct effect of systemic inflammation on myocardium and/or blood vessels.

Cardiovascular morbidity and mortality in patients with rheumatoid arthritis: vascular alterations and possible clinical implications

Mortality in patients with rheumatoid arthritis (RA) is higher than in the general population, which is due mainly to premature cardiovascular disease. Traditional cardiovascular risk factors cannot entirely explain the higher level of cardiovascular complications, and there is growing evidence that chronic inflammation is the main culprit. The aims of this review of the literature are to (i) summarize aspects of vascular alterations found in the cardiovascular system of RA patients and to relate them to the clinically relevant cardiovascular morbidity and mortality and (ii) evaluate what these abnormalities and complications might in the end imply for clinical management. A number of abnormalities in the cardiovascular system of RA patients have been identified, on the molecular level, in endothelial function, arterial stiffness, arterial morphology and, finally, in the clinical presentation of cardiovascular disease. Cardiovascular risk assessment should be part of the care of RA patients. While a great deal of data is published demonstrating abnormalities in the cardiovascular system of these patients, it is much less clear what specific interventions should be performed to reduce the incidence of cardiovascular complications. Cardiovascular care should be delivered in accordance with recommendations for the general population. Whether specific drugs (e.g. statins, aspirin) are of particular benefit in RA patients needs further investigation. Control of inflammation appears to be of benefit. Methotrexate and tumor necrosis factor-α blocking agents might reduce the number of cardiovascular events. Leflunomide, cyclosporine, non-steroidal anti-inflammatory drugs and cyclo-oxygenase-2 inhibitors may worsen cardiovascular outcome. The role of glucocorticoids in active RA remains to be determined.

Energy regulation and neuroendocrine-immune control in chronic inflammatory diseases

Energy regulation (EnR) is most important for homoeostatic regulation of physiological processes. Neuroendocrine pathways are involved in EnR. We can separate factors that provide energy-rich fuels to stores [parasympathetic nervous system (PSNS), insulin, insulin-like growth factor-1, oestrogens, androgens and osteocalcin] and those that provide energy-rich substrates to consumers [sympathetic nervous system (SNS), hypothalamic-pituitary-adrenal axis, thyroid hormones, glucagon and growth hormone]. In chronic inflammatory diseases (CIDs), balanced energy-rich fuel allocation to stores and consumers, normally aligned with circadian rhythms, is largely disturbed due to the vast fuel consumption of an activated immune system (up to 2000 kJ day(-1)). Proinflammatory cytokines such as tumour necrosis factor or interleukins 1beta and 6, circulating activated immune cells and sensory nerve fibres signal immune activation to the rest of the body. This signal is an appeal for energy-rich fuels as regulators are switched on to supply energy-rich fuels ('energy appeal reaction'). During evolution, adequate EnR evolved to cope with nonlife-threatening diseases, not with CIDs (huge negative selection pressure and reduced reproduction). Thus, EnR is inadequate in CIDs leading to many abnormalities, including sickness behaviour, anorexia, hypovitaminosis D, cachexia, cachectic obesity, insulin resistance, hyperinsulinaemia, dyslipidaemia, fat deposits near inflamed tissue, hypoandrogenaemia, mild hypercortisolaemia, activation of the SNS (hypertension), CID-related anaemia and osteopenia. Many of these conditions can contribute to the metabolic syndrome. These signs and symptoms become comprehensible in the context of an exaggerated call for energy-rich fuels by the immune system. We propose that the presented pathophysiological framework may lead to new therapeutical approaches and to a better understanding of CID sequence.

Accelerated atherosclerosis in inflammatory rheumatic diseases

Over recent years it has become clear that patients with inflammatory rheumatic diseases are at increased risk of developing atherosclerosis. The exact causes for this are probably related in part to a general adverse effect of inflammation on atherogenesis, and in part to immune mechanisms specific to individual rheumatic diseases. This review discusses proposed mechanisms of accelerated atherosclerosis, including abnormal lipid and lipoprotein profiles, oxidative stress, enhanced apoptosis, thrombophilia, immune complexes, and increased mononuclear cell infiltration of atherosclerotic lesions, and local generation of cytokines.

Insulin resistance in pulmonary arterial hypertension

Although obesity, dyslipidemia and insulin resistance (IR) are well known risk factors for systemic cardiovascular disease, their impact on pulmonary arterial hypertension (PAH) is unknown. The present authors' previous studies indicate that IR may be a risk factor for PAH. The current study has investigated the prevalence of IR in PAH and explored its relationship with disease severity. Clinical data and fasting blood samples were evaluated in 81 nondiabetic PAH females. In total, 967 National Health and Nutrition Examination Surveys (NHANES) females served as controls. The fasting triglyceride to high-density lipoprotein cholesterol ratio was used as a surrogate of insulin sensitivity. While body mass index was similar in NHANES versus PAH females (28.6 versus 28.7 kg.m(-2)), PAH females were more likely to have IR (45.7 versus 21.5%) and less likely to be insulin sensitive (IS; 43.2 versus 57.8%). PAH females mostly (82.7%) had New York Heart Association (NYHA) class II and III symptoms. Aetiology, NYHA class, 6-min walk-distance and haemodynamics did not differ between IR and IS PAH groups. However, the presence of IR and a higher NYHA class was associated with poorer 6-months event-free survival (58 versus 79%). Insulin resistance appears to be more common in pulmonary arterial hypertension females than in the general population, and may be a novel risk factor or disease modifier that might impact on survival.

Cachexia in rheumatoid arthritis is associated with inflammatory activity, physical disability, and low bioavailable insulin-like growth factor

OBJECTIVES

To examine the impact of inflammation, insulin-like growth factor (IGF-1) and its regulating binding protein (IGFBP-1) on lean body mass (LBM) in patients with rheumatoid arthritis (RA).

METHODS

In 60 inpatients (50 women), inflammatory activity was measured by Disease Activity Score 28 (DAS28), C-reactive protein (CRP), and interleukin (IL)-6, and physical disability by the Health Assessment Questionnaire (HAQ). LBM was assessed by dual-energy X-ray absorptiometry (DXA) and fat free mass index (FFMI; kg/m(2)) and fat mass index (FMI; kg/m(2)) were calculated.

RESULTS

Median age was 65 years and disease duration 13 years. Fifty per cent of the patients had FFMI below the 10th percentile of a reference population and 45% had FMI above the 90th percentile, corresponding to the condition known as rheumatoid cachexia (loss of muscle mass in the presence of stable or increased FM). DAS28, CRP, and IL-6 correlated negatively with LBM (p = 0.001, 0.001, and 0.018, respectively), as did HAQ (p = 0.001). Mean (confidence interval) IGF-1 was in the normal range, at 130 (116-143) microg/L. IGFBP-1 levels were elevated in patients (median 58 microg/L in women and 59 microg/L in men) compared with a normal population (33 microg/L in women and 24 microg/L in men). The ratio IGF-1/IGFBP-1, which reflects bioavailable IGF-1, was low (2.0 microg/L) and was positively correlated with LBM (p = 0.015). In multiple regression analysis, 42% of the LBM variance was explained by IGF-1/IGFBP-1, HAQ score, and DAS28.

CONCLUSION

A large proportion of RA inpatients, mainly women, had rheumatoid cachexia. The muscle wasting was explained by inflammatory activity and physical disability as well as low bioavailable IGF-1.

Mitochondrial depolarisation and oxidative stress in rheumatoid arthritis patients

OBJECTIVES

To investigate mitochondrial membrane integrity, lipid peroxidation and cytotoxicity in peripheral lymphocytes (PL) from rheumatoid arthritis (RA) patients.

DESIGN AND METHODS

South African black RA patients (HIV(-)) were recruited into the study. Mitochondrial membrane potential (Deltapsi(m)) was analysed in PL using the JC-1 dye distribution assay and flow cytometry. Correlations between Deltapsi(m) and clinical parameters were tested for statistical significance. Cytotoxicity (LDH) and lipid peroxidation (thiobarbituric acid reactive substances (TBARS)) was also determined.

RESULTS

Our findings show significantly elevated levels of cytotoxicity (p=0.0029) and lipid peroxidation (p=0.0030) in RA. A significantly higher percentage of circulating PL contained depolarised mitochondria (p=0.0003) which correlated with disease activity and C-reactive protein levels in patients. Collapse of Deltapsi(m) also negatively correlated to absolute lymphocyte counts (r=-0.4041; p=0.0197).

CONCLUSION

These findings suggest a possible role for mitochondrial membrane alterations in the pathology of RA.

Cardiovascular disease in rheumatoid arthritis

PURPOSE OF REVIEW

Individuals with rheumatoid arthritis are at increased risk for morbidity and mortality from cardiovascular disease (CVD). The purpose of this review is to discuss recent advances in our understanding of the pathogenesis, prevalence, treatment, and prevention of accelerated atherosclerotic disease in rheumatoid arthritis.

RECENT FINDINGS

Recent reports have highlighted the increased risk for silent myocardial infarction and sudden death in rheumatoid arthritis, and the potential roles of traditional and nontraditional risk factors for CVD, including abnormal revascularization of damaged peripheral blood vessels and genetic polymorphisms. Several studies have also added important information on the possible role of anti-tumor necrosis factor-alpha therapy, other disease modifying antirheumatic drugs, and nonsteroidal anti-inflammatory drugs in decreasing CVD risk.

SUMMARY

The pathogenic mechanisms involved in accelerated cardiovascular complications in rheumatoid arthritis appear to be complex and multifactorial. Both traditional and nontraditional risk factors potentially contribute to the increased cardiovascular risk. Good control of the inflammation, immunologic disturbances, and metabolic changes seen in rheumatoid arthritis are crucial in the prevention of this potentially lethal complication. There is a need for heightened awareness of the increased risk for silent ischemia, early myocardial infarction, and sudden death. Further exploration of the mechanisms of vascular repair and their potential role in premature atherosclerosis is needed.

Rheumatoid arthritis and cardiovascular disease

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease affecting approximately 1% of the adult general population. Cardiovascular disease is recognized as the leading cause of death in RA patients, accounting for nearly 40% of their mortality. Patients with RA are at a twofold increased risk for myocardial infarction and stroke, with risk increasing to nearly threefold in patients who have had the disease for 10 years or more. Congestive heart failure appears to be a greater contributor to excess mortality than ischemia. This increased cardiovascular disease risk in RA patients seems to be independent of traditional cardiovascular risk factors. Pathogenic mechanisms include pro-oxidative dyslipidemia, insulin resistance, prothrombotic state, hyperhomocysteinemia, and immune mechanisms such as T-cell activation that subsequently lead to endothelial dysfunction, a decrease in endothelial progenitor cells, and arterial stiffness, which are the congeners of accelerated atherosclerosis observed in RA patients. This paper discusses pathogenic mechanisms, effects of methotrexate, tumor necrosis factor antagonists, steroids, and statins, with a perspective on therapy.

Insulin resistance in patients with rheumatoid arthritis: effect of anti-TNFalpha therapy

OBJECTIVES

We undertook this study to test the hypotheses that patients with active rheumatoid arthritis (RA) are insulin resistant and that anti-tumour necrosis factor-alpha (TNFalpha) therapy improves not only the clinical state of these patients but also their glucose metabolism.

METHODS

Nine RA patients with active disease and nine healthy subjects, matched for sex, age, and body mass index (BMI), underwent a hyperinsulinaemic euglycaemic clamp. The RA patients received anti-TNFalpha therapy with Humira(adalimumab) and had the insulin clamp re-evaluated after 8 weeks of treatment.

RESULTS

Patients with RA had marked insulin resistance (glucose infusion rate (GIR) area under the curve (AUC) was 499+/-55 mg/kg in the RA group compared to 710+/-77 mg/kg in the control group; p<0.05). However, insulin sensitivity did not differ before and after 8 weeks of adalimumab therapy. The RA patients demonstrated a reduction in C-reactive protein (CRP) and interleukin-6 (IL-6) levels after the therapy as compared to pretreatment values, but there was no concomitant effect on plasma levels of TNFalpha.

CONCLUSION

RA patients with active disease showed marked insulin resistance that was not influenced by anti-TNFalpha therapy despite a reduction in systemic inflammation during the treatment.

Insulin resistance is an independent risk factor for atherosclerosis in rheumatoid arthritis

The objective of this study was to investigate the relationship between insulin resistance (IR) and subclinical atherosclerosis in patients with rheumatoid arthritis (RA). Carotid artery intima media thickness (IMT), using ultrasound evaluation, and other clinical and laboratory variables were investigated in 45 RA outpatients and in 48 controls with soft tissue disorders. IR was assayed by homeostasis model assessment (HOMA2) and metabolic syndrome by National Cholesterol Education Program Adult Treatment Panel (NCEP ATP III) criteria. Insulin resistance, as defined by HOMA2-IR>1, was seen in 40 (88.9%) RA patients and in three (6.2%) controls (p<0.001). No significant difference was detected in the prevalence of metabolic syndrome. The median IMT was greater in RA patients (0.76 mm; interquartile range [IQR] 0.65, 0.85) than in the controls (0.66 mm; IQR 0.60, 0.72) (p<0.001). Dividing the RA patients according to the cut-off IMT value (0.72 mm), a difference was detected in both systolic (p=0.04) and diastolic blood pressure (p=0.02), disease activity score (DAS28) (p=0.008), HOMA2-IR (p<0.001) and cumulative oral steroid dose (p=0.001). Moreover, the frequency of cases with increased IMT was higher in glucocorticoid users than in non-users (21/23 vs. 9/22, respectively) (p<0.001). Spearman's rho correlation showed a significant positive relationship between IMT and HOMA2-IR (p<0.001). Multivariate stepwise analysis selected HOMA2-IR plus diastolic BP plus glucocorticoid exposure as the best predictive model for subclinical atherosclerosis (R2c=0.577, F=21, p<0.001). In conclusion, this study showed a significantly higher prevalence of IR in RA patients and pointed out a significant association between IR and subclinical atherosclerosis. This relationship may be driven primarily by exposure to steroid therapy.

Unfavorable cardiovascular risk profiles in untreated and treated psoriasis patients

Psoriasis is a chronic inflammatory skin disease that is associated with an increased cardiovascular risk profile. The systemic inflammation present in psoriasis, various systemic treatments for psoriasis and an increased prevalence of unhealthy life style factors may all contribute to this unfavorable risk profile. The purpose of this article is to provide an overview of what is known about these risk factors in psoriasis, the way they influence the cardiovascular risk of psoriasis patients, and what can be done to reduce this risk. Genetic studies demonstrate that psoriasis and cardiovascular disease share common pathogenic features in which, for example inflammatory cytokines like TNF-alpha and IL-1 play an important role. The chronic inflammation in psoriasis has an unfavorable effect on the cardiovascular risk profile. Multiple cardiovascular risk factors seem to be influenced; the blood pressure, oxidative stress, dyslipidemia, endothelial cell dysfunction, homocysteine levels and blood platelet adhesion. Moreover, classic cardiovascular risk factors like smoking and obesity that have an increased prevalence among patients with psoriasis, indirectly also worsen the cardiovascular risk profile by stimulating the psoriasis activity. Systemic treatments in psoriasis reduce the cardiovascular risk by diminishing the inflammation, but it should be taken into account that most therapies also have adverse cardiovascular effects like dyslipidemia, hyperhomocysteinemia and hypertension. As a consequence preventive measures may be indicated at least during long-term treatments. Prospective research is warranted to accurately estimate the increased cardiovascular risk in psoriasis, to determine the underlying processes and to consider preventive measures according to the absolute risk of cardiovascular disease. The present overview provides data to advice health care providers to pay more attention to the cardiovascular risk profile in psoriasis patients.

Prevention of cardiovascular disease in patients with rheumatic diseases

Cardiovascular disease (CVD), the leading cause of death in the USA, has emerged as an important comorbidity in the rheumatic diseases. As disease-modifying therapies have resulted in better disease control and decreases in disease-associated mortality, it is now apparent that the prevalence of CVD and cardiovascular (CV) events is significantly increased in a number of rheumatic disorders when compared with age and gender-matched subjects from the general population. Investigations into the mechanisms of CVD in the general population have provided insights into potential mechanisms in rheumatic disease patients and possible aetiologies for their increased risk. Although there are no evidence-based guidelines for CV risk factor screening and interventions specific to patients with rheumatic disease, the best current approach utilizes evidence-based recommendations for the general population (and higher-risk subgroups) modified by what is known of CV risk factor and event prevalence in these patients.

Peripheral insulin resistance in patients with Behcet's disease

In this study, we examined peripheral insulin resistance in patients with Behçet's disease (BD) characterized by chronic inflammation and endothelial dysfunction. Fourteen patients with BD and 15 healthy controls were recruited to the study. Insulin resistance was investigated by the hyperinsulinaemic-euglycaemic glucose clamp technique. BD patients displayed an enhanced rate of insulin resistance compared to healthy controls (P = 0.014). The insulin sensitivity (M), measured as the glucose utilization rate under steady-state conditions of euglycaemia, was significantly decreased (P = 0.001) in BD patients compared to the controls (4.09 +/- 0.16 vs. 5.60 +/- 0.27 mg/kg/min). The C-reactive protein (CRP) level, but not the erythrocyte sedimentation rate (ESR), was significantly related to the presence of insulin resistance (CRP: r(s) = 0.589, P = 0.27; ESR: r(s) = 0444, P = 0112), whereas no relationship was found between the M-value and ESR or CRP. We conclude that patients with BD exhibit peripheral insulin resistance; this could be explained as the diverse consequences of inflammation and endothelial dysfunction in BD.

Rheumatoid arthritis: a disease associated with accelerated atherogenesis

OBJECTIVES

Rheumatoid arthritis (RA) is a systemic inflammatory disease associated with an increased prevalence of coronary heart disease and a high cardiovascular (CV) mortality. In this article, a review of mechanisms implicated in the development of accelerated atherogenesis in RA was performed. The potential role of treatment to reduce the incidence of CV events in RA was also discussed.

METHODS

Retrospective review of the literature. The potential mechanisms implicated in the development of accelerated atherogenesis in RA, information on carotid ultrasonography, and the potential implication of treatment to prevent accelerated atherogenesis in individuals with RA were examined.

RESULTS

Endothelial dysfunction, which is an early step in the development of atherosclerosis, has been observed in patients with RA. Deleterious effects resulting from persistent chronic inflammation may lead to endothelial dysfunction, insulin resistance, and a dyslipidemic pattern in these patients. Other mechanisms different from those related to classic atherogenesis risk factors, such as hyperhomocysteinemia and increased oxidative stress, are considered to be implicated in the pathogenesis of atherosclerosis in RA. Increased carotid intima-media thickness and carotid plaques have been found in RA patients compared with matched controls. Active MTX treatment of the disease has been associated with decreased CV mortality. Additional drugs such as statins may be considered in the management of these patients.

CONCLUSIONS

The increased prevalence of CV mortality rate in RA cannot only be explained by the presence of traditional atherosclerotic risk factors. A chronic inflammatory response may promote the development of accelerated atherogenesis in these patients. Active treatment of the disease is required to reduce the risk of developing CV complications in individuals with RA.

[Cardiovascular manifestations in rheumatoid arthritis]

Rheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by a polyarticular joint inflammation which eventually leads to joint destruction and general disability. Besides these polyarticular manifestations, several systemic immune phenomena have been described. An increased mortality in RA patients is evident and is mainly caused by an increased cardiovascular risk. The correlation between disease activity and mortality highlighted the important role of the systemic inflammatory reaction in induction and progression of vascular damaging processes. Endothelial dysfunction and vascular inflammation are important, mechanisms in atherosclerosis and induced by conventional risk factors and systemic inflammation. It has been shown that the deleterious influence of conventional risk factors is aggravated by inflammatory mediators, mainly by pro-inflammatory cytokines. In addition, certain inflammatory mediators exert damaging effects to blood vessels. Especially CRP, merely considered as a risk indicating parameter in the past, has attracted remarkable attention. Also certain RA specific immune phenomena are of considerable proatherosclerotic potential. At least in part, they could be responsible for the excess mortality in RA patients. The newer TNFalpha blocking agents interfere with different mechanisms responsible for induction and perpetuation of atherosclerotic processes. Time will show whether they make a remarkable impact on the cardiovascular mortality in RA patients.

Hypothalamic-pituitary-adrenal axis function in ankylosing spondylitis

OBJECTIVE

To assess basal function and responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis in patients with ankylosing spondylitis during dynamic testing.

METHODS

Insulin induced hypoglycaemia (IIH) (Actrapid HM 0.1 IU/kg, as intravenous bolus) was induced in 17 patients and 11 healthy controls matched for age, sex, and body mass index. Concentrations of glucose, adrenocorticotrophic hormone (ACTH), cortisol, insulin, dehydroepiandrosterone sulphate (DHEAS), 17alpha-hydroxyprogesterone, interleukin 6 (IL-6), and tumour necrosis factor alpha (TNFalpha) were determined in plasma.

RESULTS

Comparable basal cortisol levels were found in the two groups, with a trend to be lower in ankylosing spondylitis. In the ankylosing spondylitis group, there were higher concentrations of IL-6 (mean (SEM): 16.6 (2.8) pg/ml v 1.41 (0.66) pg/ml in controls; p<0.001) and TNFalpha (8.5 (1.74) pg/ml v 4.08 (0.42) pg/ml in controls; p<0.01). Glucose, insulin, ACTH, DHEAS, and 17alpha-hydroxyprogesterone did not differ significantly from control. The IIH test was carried out successfully in 11 of the 17 patients with ankylosing spondylitis, and the ACTH and cortisol responses were comparable with control. General linear modelling showed a different course of glycaemia (p = 0.041) in the ankylosing spondylitis patients who met the criteria for a successful IIH test compared with the controls.

CONCLUSIONS

The results suggest there is no difference in basal HPA axis activity and completely preserved responsiveness of the HPA axis in patients with ankylosing spondylitis. The interpretation of the different course of glycaemia during IIH in ankylosing spondylitis requires further investigation.

Explaining how "high-grade" systemic inflammation accelerates vascular risk in rheumatoid arthritis

There is intense interest in mechanisms whereby low-grade inflammation could interact with conventional and novel vascular risk factors to promote the atheromatous lesion. Patients with rheumatoid arthritis (RA), who by definition manifest persistent high levels of inflammation, are at greater risk of developing cardiovascular disease. Mechanisms mediating this enhanced risk are ill defined. On the basis of available evidence, we argue here that the systemic inflammatory response in RA is critical to accelerated atherogenesis operating via accentuation of established and novel risk factor pathways. By implication, long-term suppression of the systemic inflammatory response in RA should be effective in reducing risk of coronary heart disease. Early epidemiological observational and clinical studies are commensurate with this hypothesis. By contrast, risk factor modulation with conventional agents, such as statins, may provide unpredictable clinical benefit in the context of uncontrolled systemic inflammatory parameters. Unraveling such complex relationships in which exaggerated inflammation-risk factor interactions are prevalent may elicit novel insights to effector mechanisms in vascular disease generally.

Neutralizing interferon alpha as a therapeutic approach to autoimmune diseases

Therapeutic antibodies directed against tumor necrosis factor alpha (TNF-alpha) for the treatment of rheumatoid arthritis, and against the human EGF receptor-2 (HER2) receptor for the treatment of breast cancer have provided significant clinical benefit for the patients. The success of these antibodies has also provided strong support for the possibility that increased activity of cytokines or growth factors is causally implicated in a variety of human diseases. Interferon alpha (IFN-alpha) is induced by viruses (linked by epidemiological studies to autoimmune diseases), has significant direct effects on both epithelial cells and the immune system, and then can be further induced by the autoantibodies and apoptotic cells generated by the actions of IFN-alpha. The direct and deleterious impact on target tissues, the ability to induce an autoimmune response, and the potential for a self-sustaining cycle of induction and damage suggests that IFN-alpha could be a pivotal factor in the development of autoimmune diseases. This review will evaluate the rationale for, possible approaches to, and safety concerns associated with, targeting interferon alpha (IFN-alpha) as a therapeutic strategy for the treatment of autoimmune diseases. While the approach may be applicable to several autoimmune diseases, there will be an emphasis on systemic lupus erythematosus and insulin dependent diabetes mellitus.

Cachexia in rheumatoid arthritis

Rheumatoid arthritis is a debilitating, chronic, systemic, autoimmune disease of unknown etiology that causes destruction of joint cartilage and bone. It generally occurs between the fourth and sixth decades of life, and affects two to three times more women than men. It is characterized by joint stiffness, pain, and swelling, and is accompanied by a loss of body cell mass. This loss of cell mass, known as rheumatoid cachexia, predominates in skeletal muscle, but also occurs in the viscera and immune system. Thus, rheumatoid cachexia leads to muscle weakness and a loss of functional capacity, and is believed to accelerate morbidity and mortality in rheumatoid arthritis. Currently there is no established mechanism for rheumatoid cachexia, but it is accompanied by elevated resting energy expenditure, accelerated whole-body protein catabolism, and excess production of the inflammatory cytokines, tumor necrosis factor-alpha and interleukin-1beta. Tumor necrosis factor-alpha is probably the central mediator of muscle wasting in rheumatoid arthritis, and is known to act synergistically with interleukin-1beta to promote cachexia. In general, tumor necrosis factor-alpha and interleukin-1beta are thought to alter the balance between protein degradation and protein synthesis in rheumatoid arthritis to cause muscle wasting. The precise mechanism by which they do this is not known. Reduced peripheral insulin action and low habitual physical activity are important consequences of rheumatoid arthritis, and have also been implicated as mediators of rheumatoid cachexia. Insulin inhibits muscle protein degradation. Consequently, reduced peripheral insulin action in rheumatoid arthritis is thought to be permissive to cytokine-driven muscle loss. The cause of reduced peripheral insulin action in rheumatoid arthritis is not known, but tumor necrosis factor-alpha has been shown to interfere with insulin receptor signaling and is probably an important contributor. Low habitual physical activity has consistently been observed in rheumatoid arthritis and is an important consequence of, and contributor to, muscle wasting. In addition, low physical activity predisposes to fat gain and is believed to precipitate a negative reinforcing cycle of muscle loss, reduced physical function, and fat gain in rheumatoid arthritis, which leads to 'cachectic obesity'. To date, there is no standard treatment for rheumatoid cachexia. However, physical exercise is currently believed to be the most important and clinically relevant countermeasure against rheumatoid cachexia. In general, a combination of skeletal muscle strength training and aerobic exercise is recommended, but must be prescribed with the patient's disease status, overall health, and safety in mind. Future studies should investigate the safety, efficacy, and required dose of anti-cytokine therapy for the treatment of rheumatoid cachexia. In this review, we outline the current definition of rheumatoid cachexia, and discuss the etiology, pathogenesis, and treatment of rheumatoid cachexia.

Tumour necrosis factor in chronic heart failure: a peripheral view on pathogenesis, clinical manifestations and therapeutic implications

The development of chronic heart failure (CHF) includes phenotypic changes in a host of homeostatic systems so that, as the disease advances, CHF may be seen as a multi-system disorder with its origins in the heart but embracing many extra-cardiac manifestations. Immunological abnormalities are recognised in this context, in particular, changes in the expression of mediators of the innate immune response. Higher levels of the pro-inflammatory cytokine tumor necrosis factor (TNF) are found in the circulation and in the myocardium of patients with CHF than in controls, and TNF has been implicated in a number of pathophysiological processes that are thought important to the progression of CHF. Therapies directed against this cytokine therefore represent a novel approach to heart failure management. Anti-TNF strategies in CHF may target the mechanisms of immune activation, the intracellular pathways regulating TNF production, or the fate of TNF once it has been released into the circulation. Circulating endotoxin may be an important stimulus to TNF production by circulating monocytes, tissue macrophages and cardiac myocytes in CHF and efforts to limit this phenomenon are of interest. Several established pharmacological therapies for patients with CHF, including angiotensin converting enyzme inhibitors, beta-blockers, and phosphodiesterase inhibitors may modify cellular TNF production by their action on intracellular mechanisms, whereas TNF receptor fusion proteins have been developed that target circulating TNF itself. Patients with New York Heart Association class IV symptoms, those with cardiac cachexia and those with oedematous decompensation of their disease have the highest serum TNF levels and are most likely to benefit most from such a therapeutic approach.

Glucose regulation of the IGF response system in chondrocytes: induction of an IGF-I-resistant state

Nonresponsiveness to the growth-stimulatory actions of insulin-like growth factor (IGF)-I in chondrocytes has been reported in a number of disease states associated with impaired glucose metabolism. Primary rabbit chondrocytes were investigated for changes in their IGF response system [type-I IGF receptor and IGF-binding protein (IGFBP) expression] and in their ability to mount a synthetic response to IGF-I [as 35S-labeled proteoglycan ([35S]PG) production] in media containing varying ambient glucose concentrations. Whereas basal [35S]PG synthetic rate was unaffected by glucose concentration, synthetic responsiveness to IGF-I was lost in media containing <5 mmol/l glucose or in media containing a "diabetic" glucose concentration (25 mmol/l). IGFBP expression, as measured by Northern analysis of mRNA levels and Western ligand blotting of secreted protein levels, was not significantly altered in the different glucose media, nor were there any differences in the cell surface localization of IGFBPs as assessed by affinity cross-linking with 125I-labeled IGF-I, suggesting that IGFBPs do not induce the IGF-I resistance. The nonresponsiveness to IGF-I in reduced glucose occurred with 25-50% reductions in steady-state levels of IGF type-I receptor mRNA and protein. A significant correlation between IGF receptor mRNA level and synthetic response to IGF-I was observed between 0 and 10 mmol/l glucose concentrations, suggesting that the loss of responsiveness in reduced glucose is manifested at the level of transcription and/or receptor mRNA stability. In contrast, nonresponsiveness to IGF-I in chondrocytes in diabetic glucose concentrations occurred without changes in receptor mRNA and protein levels, suggesting that IGF-I resistance was due to post-ligand-binding receptor defects. It is proposed that IGF-I resistance in chondrocytes subjected to inappropriate glucose levels may constitute an important pathogenic mechanism in degenerative cartilage disorders.

The estrogen connection: the etiological relationship between diabetes, cancer, rheumatoid arthritis and psychiatric disorders

For some considerable time, there has been a growing awareness that defective essential fatty acid metabolism plays a causal role in the pathogenesis of both schizophrenia and non-insulin-dependent diabetes mellitus (NIDDM) but the influence of defective essential fatty acid metabolism in the pathogenesis of rheumatoid arthritis and cancer is less well appreciated. An EFA deficiency, or defective EFA metabolism, negatively influences prostaglandin synthesis and glucose regulation and transport. Moreover, defective EFA metabolism negatively influences estrogen availability which contributes to the observed gender bias some of these illnesses manifest. While fluctuations of estrogen are known to contribute to the pathogenesis of these conditions, so also do fluctuations of IGF-II and there is some suggestion that IGF-II and insulin may well be inversely regulated. In addition, insulin-dependent diabetes mellitus (IDDM), rheumatoid arthritis, and schizophrenia are thought to be autoimmune disorders, while cancer is associated with immune system failure. Consequently, this paper aims to examine the pathophysiological similarities and differences between mental illness, diabetes, rheumatoid arthritis and cancer in respect of which the causal relationship that obtains between essential fatty acids, estrogen, IGF-II, glucose regulation and autoimmunity will be addressed.

Total-body and myocardial substrate oxidation in congestive heart failure

Congestive heart failure is a condition associated with increased plasma norepinephrine levels, which have been demonstrated to impair glucose handling. In the present study, 10 patients suffering from congestive heart failure and 10 healthy age- and body mass index-matched subjects were submitted to a hyperinsulinemic (insulin infusion rate, 0.5 mU/kg.min-1) glucose clamp, while simultaneous D-3H-glucose infusion and indirect calorimetry allowed for determination of glucose turnover parameters and substrate oxidation, respectively. On a separate day, basal local (myocardial) indirect calorimetry was also performed. Our data demonstrate that in congestive heart failure, fasting myocardial glucose oxidation (Gox) was inhibited with a simultaneous increase in lipid oxidation (Lox). In our patients, a significant decrease in total-body insulin-stimulated glucose metabolism (31.0 +/- 0.5 v 20.3 +/- 0.4 mumol/kg.min-1, P < .01) and nonoxidative glucose metabolism (18.9 +/- 1.1 v 11.0 +/- 0.5 mumol/kg.min-1, P < .05) was also found. Such latter changes were also associated with a simultaneous overdrive of Lox (0.4 +/- 0.2 v 1.9 +/- 0.2 mumol/kg.min-1, P < .02) that was correlated with an enhanced availability of plasma free fatty acids (FFAs).

Different contribution of substrates oxidation to insulin resistance in malnourished elderly patients with cancer

BACKGROUND

The relative contribution of malnutrition and cancer to insulin resistance in elderly patients is still poorly understood.

METHODS

Twenty malnourished and 15 well-nourished patients with cancer matched for age (70 +/- 0.3 versus 69 +/- 0.3 years; P = not significant), mean arterial blood pressure (104 +/- 8 versus 107 +/- 7 mm Hg; P = not significant), gender ratio (10 males/10 females versus 7 males/8 females), and sedentary life style underwent an euglycemic glucose clamp. Simultaneous infusion of 3-D-H-glucose and indirect calorimetry allowed the authors to determine glucose turnover parameters and analyze substrates oxidation.

RESULTS

Malnourished patients displayed a reduced total body glucose metabolism (36 +/- 2 versus 31 +/- 3 mumol/kg of lean body mass x min P < 0.04) despite higher glucose oxidation. In the same group of patients, the authors demonstrated a significant increase in lipid oxidation and the lack of the inverse relationship between glucose and lipid oxidation (r = 0.07; P = not significant). Insulin infusion enhanced glucose oxidation and suppressed lipid oxidation, but such changes were at lower extent in malnourished patients.

CONCLUSIONS

Our study confirms the presence of insulin resistance in malnourished patients and demonstrates the relative contribution of substrates oxidation to the insulin resistance itself.