Cardiometabolic comorbidities and rheumatic diseases: focus on the role of fat mass and adipokines

Sex Difference in the Association Between Metabolic Syndrome and Obstructive Coronary Artery Disease: Analysis of Data from the KoRean wOmen'S chest pain rEgistry (KoROSE)

Background: The sex-related impact of metabolic syndrome (MetS) on obstructive coronary artery disease (OCAD) has not been well evaluated. Methods: A total of 1156 patients (62 years and 58% women) with chest pain undergoing invasive coronary angiography (CAG) were recruited from the database of the nation-wide chest pain registry. MetS was defined according to the criteria of the International Diabetes Federation. OCAD was defined as ≥50% stenosis of the left main coronary artery and/or ≥70% stenosis of any other coronary arteries. Results: Women were older than men (65 vs. 59 years, p < 0.001). OCAD (32.0% vs. 30.9%) and MetS (27.8% vs. 27.9%) prevalence rates were similar in both sexes (p > 0.05). The presence of MetS was associated with higher prevalence of OCAD in women (24.5% vs. 47.3%, p < 0.001), but not in men (31.0% vs. 34.3%, p = 0.487). The linear association between the number of components meeting MetS criteria and OCAD prevalence was significant in both sexes (p < 0.001 for each), but it was stronger in women than in men (Chi-square value: 81.9 vs. 14.8, p < 0.001). In a multivariable model, the presence of MetS was independently associated with OCAD in women even after controlling for potential confounders (odds ratio, 1.92; 95% confidence interval, 1.31-2.81; p = 0.001). Conclusions: In patients with chest pain undergoing invasive CAG, the association between the number of components meeting MetS criteria and OCAD prevalence was stronger in women than in men.

High prevalence of obesity in rheumatoid arthritis patients: association with disease activity, hypertension, dyslipidemia and diabetes, a multi-center study

INTRODUCTION

Rheumatoid arthritis (RA) is a well-documented independent risk factor for cardiovascular disease. Obesity may provide an additional link between inflammation and accelerated atherosclerosis in RA.

OBJECTIVE

To evaluate the association between obesity and disease parameters and cardiovascular risk factors in RA patients.

METHOD

Cross-sectional study of a cohort of RA patients from three Brazilian teaching hospitals. Information on demographics, clinical parameters and the presence of cardiovascular risk factors was collected. Blood pressure, weight, height and waist circumference (WC) were measured during the first consultation. Laboratory data were retrieved from medical records. Obesity was defined according to the NCEP/ATPIII and IDF guidelines. The prevalence of obesity was determined cross-sectionally. Disease activity was evaluated using the DAS28 system (remission < 2.6; low 2.6-3.1; moderate 3.2-5.0; high > 5.1).

RESULTS

The sample consisted of 791 RA patients aged 54.7 ± 12.0 years, of whom 86.9% were women and 59.9% were Caucasian. The mean disease duration was 12.8 ± 8.9 years. Three quarters were rheumatoid factor-positive, the mean body mass index (BMI) was 27.1 ± 4.9, and the mean WC was 93.5 ± 12.5 cm. The observed risk factors included dyslipidemia (34.3%), type-2 diabetes (15%), hypertension (49.2%) and family history of premature cardiovascular disease (16.5%). BMI-defined obesity was highly prevalent (26.9%) and associated with age, hypertension and dyslipidemia. Increased WC was associated with diabetes, hypertension, dyslipidemia and disease activity.

CONCLUSION

Obesity was highly prevalent in RA patients and associated with disease activity.

Effects of Tocilizumab, an Anti-Interleukin-6 Receptor Antibody, on Serum Lipid and Adipokine Levels in Patients with Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA) are at increased risk of cardiovascular disease. Dyslipidemia is a known adverse effect of tocilizumab (TCZ), an anti-interleukin-6 receptor antibody used in RA treatment. We aimed to assess the effect of TCZ on lipid profile and adipokine levels in RA patients. Height, weight, disease activity scores, lipid profile and atherogenic indices (AI), leptin, adiponectin, resistin, interleukin-6, and high-sensitivity C-reactive protein (CRP) were measured before and four months after initiation of TCZ in 40 RA patients and 40 healthy controls. Following TCZ treatment, total cholesterol, high density lipoprotein (HDL), and triglycerides were significantly elevated, but no significant changes in weight, body mass index (BMI), low density lipoprotein (LDL), and AI were observed. Compared with controls, significantly higher adiponectin levels were measured in the RA group at baseline. Following TCZ treatment, resistin levels and the leptin-to-adiponectin ratio increased, adiponectin levels decreased, and leptin levels remained unchanged. No correlation was found between the change in adipokine serum levels and changes in the disease activity indices, nor the lipid profile. In conclusion, the changes observed suggest a protective role for TCZ on the metabolic and cardiovascular burden associated with RA, but does not provide a mechanistic explanation for this phenomenon.

Adipocytokines in Rheumatoid Arthritis: The Hidden Link between Inflammation and Cardiometabolic Comorbidities

Rheumatoid arthritis is a chronic autoimmune disease affecting typically synovial joints and leading to progressive articular damage, disability, and reduced quality of life. Despite better recent therapeutic strategies improving long-term outcomes, RA is associated with a high rate of comorbidities, infections, malignancies, and cardiovascular disease (CVD). Remarkably, some well-known pathogenic proinflammatory mediators in RA, such as interleukin-1β (IL-1β) and tumor necrosis factor (TNF), may play a pivotal role in the development of CVD. Interestingly, different preclinical and clinical studies have suggested that biologic agents commonly used to treat RA patients may be effective in improving CVD. In this context, the contribution of adipocytokines has been suggested. Adipocytokines are pleiotropic molecules, mainly released by white adipose tissue and immune cells. Adipocytokines modulate the function of different tissues and cells, and in addition to energy homeostasis and metabolism, amplify inflammation, immune response, and tissue damage. Adipocytokines may contribute to the proinflammatory state in RA patients and development of bone damage. Furthermore, they could be associated with the occurrence of CVD. In this study, we reviewed available evidence about adipocytokines in RA, because of their involvement in disease activity, associated CVD, and possible biomarkers of prognosis and treatment outcome and because of their potential as a possible new therapeutic target.

No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases

Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.

Metabolic syndrome as a risk factor for total hip or knee replacement due to primary osteoarthritis: a prospective cohort study (the HUNT study and the Norwegian Arthroplasty Register)

Objective

Biochemical changes associated with obesity may accelerate osteoarthritis beyond the effect of mechanical factors. This study investigated whether metabolic syndrome and its components (visceral obesity, hypertension, dyslipidemia and insulin resistance) were risk factors for subsequent total hip replacement (THR) or total knee replacement (TKR) due to primary osteoarthritis.

Design

In this prospective cohort study, data from the second survey of the Nord-Trøndelag Health Study 2 (HUNT2) were linked to the Norwegian Arthroplasty Register for identification of the outcome of THR or TKR. The analyses were stratified by age (<50, 50–69.9 and ≥70 years) and adjusted for gender, body mass index, smoking, physical activity and education.

Results

Of the 62,661 participants, 12,593 (20.1%) were identified as having metabolic syndrome, and we recorded 1,840 (2.9%) THRs and 1,111 (1.8%) TKRs during a mean follow-up time of 15.4 years. Cox regression analyses did not show any association between full metabolic syndrome and THR or TKR, except in persons <50 years with metabolic syndrome who had a decreased risk of THR (hazard ratio [HR] 0.58, 95% CI 0.40–0.83). However, when including only participants whose exposure status did not change during follow-up, this protective association was no longer significant. Increased waist circumference was associated with increased risk of TKR in participants <50 years (HR 1.62, 95% CI 1.10–2.39) and 50–69.9 years (HR 1.43, 95% CI 1.14–1.80). Hypertension significantly increased the risk of TKR in participants <50 years (HR 1.38, 95% CI 1.05–1.81), and this risk was greater for men.

Conclusion

This study found an increased risk of TKR in men <50 years with hypertension and persons <70 years with increased waist circumference. Apart from this, neither metabolic syndrome nor its components were associated with increased risk of THR or TKR due to primary osteoarthritis.

Leptin and adiponectin in patients with systemic lupus erythematosus: clinical and laboratory correlations

OBJECTIVE

To evaluate the serum levels of leptin and adiponectin in patients with systemic lupus erythematosus (SLE) and correlate their levels with disease activity, presence of autoantibodies and clinical manifestations.

METHODS

52 women with SLE and 33 healthy women were evaluated. The patients were divided into two groups, the first with active SLE and the second with inactive SLE. Patients with SLEDAI ≥3 were considered active. Serum levels of leptin (ng/ml) and adiponectin (μg/ml) were measured by enzyme immunoassay.

RESULTS

There was a significant difference in leptin levels between SLE and controls (20.7 ± 17.1 vs. 8.0 ± 5.0 ng/mL, P <0.001), but no significant difference in adiponectin levels (87.5 ± 69.7 vs. 118.1 ± 70.6 pg/ml, P = 0.053). No significant difference in levels of leptin and adiponectin was noted between inactive and active SLE groups. There was a significant association between low levels of leptin and positivity for anticardiolipin (aCL) (P = 0.025) and lupus anticoagulant (LA) (p = 0.003) and a significant association between high levels of leptin and the presence of renal disease (p <0.001). However, there was no association between adiponectin levels with autoantibodies and clinical features in SLE patients.

CONCLUSION

Patients with SLE had elevated leptin levels, with association with renal involvement. Leptin and adiponectin were not correlated with disease activity. Low levels of leptin have been associated with the presence of LA and aCL.

Adipokines, metabolic syndrome and rheumatic diseases

The metabolic syndrome (MetS) is a cluster of cardiometabolic disorders that result from the increasing prevalence of obesity. The major components of MetS include insulin resistance, central obesity, dyslipidemia, and hypertension. MetS identifies the central obesity with increased risk for cardiovascular diseases (CVDs) and type-2 diabetes mellitus (T2DM). Patients with rheumatic diseases, such as rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus, and ankylosing spondylitis, have increased prevalence of CVDs. Moreover, CVD risk is increased when obesity is present in these patients. However, traditional cardiovascular risk factors do not completely explain the enhanced cardiovascular risk in this population. Thus, MetS and the altered secretion patterns of proinflammatory adipokines present in obesity could be the link between CVDs and rheumatic diseases. Furthermore, adipokines have been linked to the pathogenesis of MetS and its comorbidities through their effects on vascular function and inflammation. In the present paper, we review recent evidence of the role played by adipokines in the modulation of MetS in the general population, and in patients with rheumatic diseases.

High prevalence of metabolic syndrome in Takayasu arteritis: increased cardiovascular risk and lower adiponectin serum levels

OBJECTIVE

The prevalence of metabolic syndrome (MetS) tends to be high among rheumatic patients, and cardiovascular disease is the leading cause of death in these conditions. We aimed to determine the prevalence of MetS in patients with Takayasu arteritis (TA) and its association with risk factors and adipokine and cytokine levels.

METHODS

A cross-sectional study was conducted in 45 consecutive women with TA and 47 healthy controls matched by age and body mass index.

RESULTS

The prevalence of MetS (International Diabetes Federation/American Heart Association criteria) was higher in TA compared to controls (33.34 vs 8.51%, p = 0.003). Patients with TA had a higher frequency of hypertension (p < 0.001) and dyslipidemia (p = 0.001) and higher levels of insulin (p = 0.021), homeostasis model assessment index (p = 0.024), apolipoprotein E (p = 0.029), resistin (p = 0.018), and C-reactive protein (CRP, p < 0.001) compared to healthy subjects, with similar levels of adiponectin and plasminogen activator inhibitor-1 (PAI-1; p > 0.05). Further analysis of patients with TA with and without MetS revealed a higher frequency of overweight/obesity (66.66 vs 26.66%, p = 0.022), higher Framingham score ≥ 1 (p = 0.032), and lower adiponectin levels (20.37 ± 21.16 vs 38.64 ± 22.62 μg/ml, p = 0.022) in the patients with MetS. No differences were found regarding disease duration, activity, glucocorticoid use, resistin, and PAI-1 levels in the 2 groups of patients with TA (p > 0.05). Patients with and without MetS showed no differences in cytokine levels [interleukin 12 (IL-12, IL-1a, IL-6) and tumor necrosis factor-α]. IL-6 had a positive Pearson correlation with CRP only in TA patients with MetS (r = 0.57; p = 0.050).

CONCLUSION

A high prevalence of MetS was observed in patients with TA and this comorbidity seems to identify a subgroup of overweight/obese patients with high cardiovascular risk without a significant association with disease status. Further longitudinal studies are necessary to observe the effects of controlling this modifiable risk factor in the quality of life and survival of patients with TA.

Statin use and clinical osteoarthritis in the general population: a longitudinal study

BACKGROUND

One hypothesis has posited whether abnormal lipid metabolism might be a causal factor in the pathogenesis of osteoarthritis (OA). Routine statin use in clinical practice provides the basis for a natural experiment in testing this hypothesis.

OBJECTIVE

To test the hypothesis that statins reduce the long-term occurrence of clinically defined OA.

DESIGN

Cohort design with a 10-year follow-up.

PARTICIPANTS

16,609 adults cardiovascular disease cohorts aged 40 years and over from the UK General Practice Research Database with data available to 31 December 2006.

INTERVENTION

Statins were summarised as annual mean daily dose and dose change over two-year time periods.

MAIN MEASURES

Incident episode of clinically defined osteoarthritis was assessed within 2 years, and at 4-year and 10-year follow-up time periods, using Cox and discrete time survival analysis. Covariates included age, gender, deprivation, body mass index, cholesterol level, pain-modifying drug co-therapies, and duration and severity of cardiovascular disease.

KEY RESULTS

Higher therapeutic dose of statin, with a treatment duration of at least 2 years was associated with a significant reduction in clinical OA compared to non-statin users in the follow-up time period. The estimated adjusted rate ratios were as follows: lowest statin dose quartile 1: 2.5 (95 % CI 2.3, 2.9); quartile 2: 1.3 (1.1, 1.5); quartile 3: 0.8 (0.7, 0.95); and highest statin dose quartile 4: 0.4 (0.3, 0.5). The largest statin dose increments were associated with significant reductions estimated at 18 % in OA outcome within 2 years and 40 % after 4 years, compared to non-statin users.

CONCLUSIONS

This longitudinal study from a national clinical practice setting provides evidence that higher statin dose and larger statin dose increments were associated with a reduction in clinically defined OA outcome.

Sex differences in assessment of obesity in rheumatoid arthritis

OBJECTIVE

To determine the prevalence of obesity and how accurately standard anthropometric measures identify obesity among men and women with rheumatoid arthritis (RA).

METHODS

Dual x-ray absorptiometry (DXA) was performed for 141 persons with RA (56 men and 85 women). Two anthropometric proxies of obesity (body mass index [BMI] and waist circumference [WC]) were compared to a DXA-based obesity criterion. Receiver operating characteristic curves determined optimal cut points for each anthropometric measure, relative to DXA. The association of body fat and anthropometric obesity measures with disease status and cardiovascular risk was assessed in multiple regression analyses, controlling for age and glucocorticoid use. All analyses were performed separately for men and women.

RESULTS

A total of 20%, 32%, and 44% of women and 41%, 36%, and 80% of men were classified as obese by BMI, WC, and DXA, respectively. Cut points were identified for anthropometric measures to better approximate DXA estimates of percent body fat (BMI ≥26.1 kg/m(2) for women and ≥24.7 kg/m(2) for men; WC ≥83 cm for women and ≥96 cm for men). For women and men, higher percent fat was associated with poorer RA status. Anthropometric measures were more closely linked to RA status for women, but identified cardiovascular risk for both women and men.

CONCLUSION

A large percentage of this RA sample was overfat; DXA-defined obesity was twice as common in men as in women. Utility of revised BMI and WC cut points compared to traditional cut points remains to be examined in prospective studies, but results suggest that lower, sex-specific cut points may be warranted to better identify individuals at risk for poor RA and/or cardiovascular outcomes.

Autoimmune heart disease: role of sex hormones and autoantibodies in disease pathogenesis

Cardiovascular disease (CVD) and autoimmune diseases (ADs) are the first and third highest causes of death in the USA, respectively. Men have an increased incidence of the majority of CVDs, including atherosclerosis, myocarditis, dilated cardiomyopathy and heart failure. By contrast, nearly 80% of all ADs occur in women. However, in one category of ADs, rheumatic diseases, CVD is the main cause of death. Factors that link rheumatic ADs to CVD are inflammation and the presence of autoantibodies. In this review we will examine recent findings regarding sex differences in the immunopathogenesis of CVD and ADs, explore possible reasons for the increased occurrence of CVD within rheumatic ADs and discuss whether autoantibodies, including rheumatoid factor, could be involved in disease pathogenesis.

Pathobiology of obesity and osteoarthritis: integrating biomechanics and inflammation

Obesity is a significant risk factor for developing osteoarthritis in weight-bearing and non-weight-bearing joints. Although the pathogenesis of obesity-associated osteoarthritis is not completely understood, recent studies indicate that pro-inflammatory metabolic factors contribute to an increase in osteoarthritis risk. Adipose tissue, and in particular infrapatellar fat, is a local source of pro-inflammatory mediators that are increased with obesity and have been shown to increase cartilage degradation in cell and tissue culture models. One adipokine in particular, leptin, may be a critical mediator of obesity-associated osteoarthritis via synergistic actions with other inflammatory cytokines. Biomechanical factors may also increase the risk of osteoarthritis by activating cellular inflammation and promoting oxidative stress. However, some types of biomechanical stimulation, such as physiologic cyclic loading, inhibit inflammation and protect against cartilage degradation. A high percentage of obese individuals with knee osteoarthritis are sedentary, suggesting that a lack of physical activity may increase the susceptibility to inflammation. A more comprehensive approach to understanding how obesity alters daily biomechanical exposures within joint tissues may provide new insight into the protective and damaging effects of biomechanical factors on inflammation in osteoarthritis.

Adiponectin associates with markers of cartilage degradation in osteoarthritis and induces production of proinflammatory and catabolic factors through mitogen-activated protein kinase pathways

Introduction

Adiponectin is an adipokine that regulates energy metabolism and insulin sensitivity, but recent studies have pointed also to a role in inflammation and arthritis. The purpose of the present study was to investigate the association and effects of adiponectin on inflammation and cartilage destruction in osteoarthritis (OA).

Methods

Cartilage and blood samples were collected from 35 male OA patients undergoing total knee replacement surgery. Preoperative radiographs were evaluated using Ahlbäck classification criteria for knee OA. Circulating concentrations of adiponectin and biomarkers of OA, that is, cartilage oligomeric matrix protein (COMP) and matrix metalloproteinase 3 (MMP-3), were measured. Cartilage samples obtained at the time of surgery were cultured ex vivo, and the levels of adiponectin, nitric oxide (NO), IL-6, MMP-1 and MMP-3 were determined in the culture media. In addition, the effects of adiponectin on the production of NO, IL-6, MMP-1 and MMP-3 were studied in cartilage and in primary chondrocyte cultures.

Results

Plasma adiponectin levels and adiponectin released from OA cartilage were higher in patients with the radiologically most severe OA (Ahlbäck grades 4 and 5) than in patients with less severe disease (Ahlbäck grades 1 to 3). Plasma adiponectin concentrations correlated positively with biomarkers of OA, that is, COMP (r = 0.55, P = 0.001) and MMP-3 (r = 0.34, P = 0.046). Adiponectin was released by OA cartilage ex vivo, and it correlated positively with production of NO (r = 0.43, P = 0.012), IL-6 (r = 0.42, P = 0.018) and MMP-3 (r = 0.34, P = 0.051). Furthermore, adiponectin enhanced production of NO, IL-6, MMP-1 and MMP-3 in OA cartilage and in primary chondrocytes in vitro in a mitogen-activated protein kinase (MAPK)-dependent manner.

Conclusions

The findings of this study show that adiponectin is associated with, and possibly mediates, cartilage destruction in OA.

What's new in our understanding of the role of adipokines in rheumatic diseases?

Important advances in our understanding of the relationships between adipokines, inflammation and the immune response have been achieved in the past 10 years. White adipose tissue has emerged as a highly dynamic organ that releases a plethora of immune and inflammatory mediators that are involved in numerous diseases, including not only rheumatic diseases such as rheumatoid arthritis, osteoarthritis and systemic lupus erythematosus, but also cardiovascular and metabolic complications that are frequently observed in rheumatic diseases. Our rapidly growing knowledge of adipokine biology is revealing the complexity of these amazing proteins, thereby redefining white adipose tissue as a key element of the inflammatory and immune response in rheumatic diseases. Adipokines exert potent modulatory actions on target tissues and cells involved in rheumatic disease, including cartilage, synovium, bone and various immune cells. In this Review, we describe the most recent advances in adipokine research in the context of rheumatic diseases, focusing primarily on leptin, adiponectin, visfatin and resistin, and also the potential role of newly identified adipokines such as chemerin, lipocalin 2 and serum amyloid A3.