Age impacts on the independent relationships of leptin with cardiometabolic risk and surrogate markers of enhanced early atherogenesis in black and white patients with rheumatoid arthritis: a cross-sectional study

Cardiovascular Consequences of Autoimmune Rheumatic Diseases

The increased risk of cardiovascular disease (CVD) among patients with autoimmune rheumatic diseases such as rheumatoid arthritis, spondyloarthritis and systemic lupus erythematosus has been extensively documented. Sub-clinical atherosclerosis can be assessed using various non-invasive imaging techniques. However, the mechanisms underlying the higher risk of atherosclerotic CVD in patients with autoimmune rheumatic diseases are not fully known, although they seem to include chronic low-grade systemic inflammation leading to prolonged endothelial activation, accompanied by a pro-thrombotic/pro-coagulant and autoantibody state. Furthermore, sub-clinical atherosclerosis is also influenced by other traditional risk factors for CVD. Including the individual components of the metabolic syndrome (MetS: obesity, impaired glucose metabolism, dyslipidemia and high blood pressure), the degree of which is higher in these patients than in controls. The aim of this narrative review is to discuss the CV manifestations and risk factors involved in the increased risk of CVD among patients with autoimmune rheumatic diseases.

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.

Peripheral blood leptin and resistin levels as clinical activity biomarkers in Mexican Rheumatoid Arthritis patients

OBJECTIVE

To evaluate the association between the clinical activity of RA patients and serum adipocytokines (Leptin, Adiponectin and Resistin) and inflammatory cytokines.

METHODS

All RA patients fulfilled ACR 1987 criteria and were treated with DMARDs. Adipocytokine and inflammatory cytokine levels were evaluated using ELISA.

RESULTS

121 patients were included in the study. Stratifying according to DAS28 (low, moderate and high activity), there were significant differences for Leptin, Resistin, IL-6 and IL-17, however, no differences were seen for Adiponectin, TNFα or IL-1β. Clinical activity positively correlated with Leptin, Resistin, IL-17 and IL-6 levels, but not with Adiponectin, TNFα or IL-1β. Adiponectin levels negatively correlated with TNFα and positively correlated with IL-1β. IL-1β positively correlated with IL-6 and negatively correlated with TNFα and IL-17.

CONCLUSION

Circulating Leptin, Resistin, IL-6 and IL-17 levels positively correlate with RA clinical activity in a manner independent of the subject's BMI. Complex relationships between inflammatory cytokines were observed in RA patients suggesting that other metabolic or inflammatory factors could be involved.

The role of leptin in the pathophysiology of rheumatoid arthritis

The past 20 years of research on leptin has provided important insights into its role in rheumatoid arthritis (RA). Leptin is one of the different adipokines produced by the adipose tissue that influences the endocrine system, energy homeostasis and the immune response in several ways. Leptin is known to have predominantly pro-inflammatory effects, especially in the setting of chronic inflammation. Animal models of arthritis have illustrated well the participation of leptin in the inflammatory response within the joints. In patients with RA, numerous studies have evaluated the concentrations of leptin in the bloodstream and/or the joint cavity, showing higher levels compared to control populations. Leptin has also been found to correlate with clinical or biological measurements of disease activity of RA. Conversely, the relationship between serum leptin and joint structural damage is less evident. Leptin may also promote the development of atherosclerosis in RA and may contribute to the cardiovascular consequences of the metabolic syndrome that coexists with RA. Indeed, leptin could be a link between inflammation, metabolic risk factors and cardiovascular diseases in RA. Finally, due to abnormal body composition phenotypes with an increased prevalence of obesity in RA, the therapeutic response to traditional DMARDs and/or biological agents may be attenuated. This review discusses the multiple interplays that have been described between leptin and the clinical, radiographic and therapeutic aspects of RA.

Emerging role of leptin in rheumatoid arthritis

Numerous studies have suggested the importance of leptin against autoimmune diseases such as systemic lupus erythematosus (SLE), multiple sclerosis (MS) and psoriasis. To summarize our current understanding of the role of leptin in inflammatory responses and rheumatoid arthritis (RA), a systematic review was conducted to assess the discrepancy of leptin in RA and its effect on immunity according to different studies. Recently, emerging data have indicated that leptin is involved in the pathological function of RA, which is common in autoimmune disorders. This review discusses the possible consequences of leptin levels in RA. Blocking the key signal pathways of leptin and inhibiting the leptin activity-like leptin antagonist may be a promising way for potential therapeutic treatment of RA at risk of detrimental effects. However, leptin was increased in patients with RA and may also regulate joint damage. Thus, more understanding of the mechanism of leptin in RA would be advantageous in the future.

Cardiovascular disease risk amongst African black patients with rheumatoid arthritis: the need for population specific stratification

Rheumatoid arthritis (RA) enhances the risk of cardiovascular disease to a similar extent as diabetes. Whereas atherogenesis remains poorly elucidated in RA, traditional and nontraditional risk factors associate similarly and additively with CVD in RA. Current recommendations on CVD risk stratification reportedly have important limitations. Further, reported data on CVD and its risk factors derive mostly from data obtained in the developed world. An earlier epidemiological health transition is intrinsic to persons living in rural areas and those undergoing urbanization. It is therefore conceivable that optimal CVD risk stratification differs amongst patients with RA from developing populations compared to those from developed populations. Herein, we briefly describe current CVD and its risk factor profiles in the African black population at large. Against this background, we review reported data on CVD risk and its potential stratification amongst African black compared to white patients with RA. Routinely assessed traditional and nontraditional CVD risk factors were consistently and independently related to atherosclerosis in African white but not black patients with RA. Circulating concentrations of novel CVD risk biomarkers including interleukin-6 and interleukin-5 adipokines were mostly similarly associated with both endothelial activation and atherosclerosis amongst African black and white RA patients.

Circulating concentrations of the novel adipokine chemerin are associated with cardiovascular disease risk in rheumatoid arthritis

OBJECTIVE

Depending on physiological context, the adipokine chemerin can reduce or enhance cardiovascular risk. We investigated whether chemerin concentrations represent cardiovascular disease risk in rheumatoid arthritis (RA).

METHODS

We assessed ELISA-determined chemerin concentrations and those of 4 early endothelial activation molecules as well as angiopoietin 2, which mediates angiogenesis and thereby contributes to advanced atherosclerosis, the common carotid artery intima-media thickness (cIMT), and carotid artery plaque by ultrasound in 236 patients (114 black and 122 white) with RA. Relationships were identified in potential confounder and mediator-adjusted mixed regression models.

RESULTS

Mean (SD) chemerin and median (interquartile range) angiopoietin 2 concentrations were 114 (35) ng/ml and 2560 (2044-3341) pg/ml, respectively; the mean (SD) cIMT was 0.708 (0.110) mm, and 40.3% of patients had plaque. Chemerin concentrations were not related to those of early endothelial activation molecules, but associated with those of angiopoietin 2 [β SE = 0.002 (0.0004), p < 0.0001] and plaque [OR 1.006 (95% CI 1.00-1.013), p = 0.05] in all patients. The presence of major conventional cardiovascular risk factors, generalized and abdominal obesity, and RA severity markers modified the independent chemerin-cardiovascular risk relations (interaction p < 0.05). Consequently, chemerin concentrations were associated with cIMT in those with but not without overweight or generalized obesity and abdominal obesity [β SE = 0.001 (0.0003), p = 0.005 and 0.001 (0.0001), p = 0.001 vs -0.001 (0.0004), p = 0.2 and -0.0002 (0.0004), p = 0.6, respectively], and with plaque in those without but not with generalized obesity [OR 1.008 (95% CI) 1.000-1.016, p = 0.03 vs 1.003 (0.990-1.017), p = 0.6, respectively]. The β (SE) for the chemerin-intima-media thickness relations in patients with overweight or generalized obesity and abdominal obesity were larger than in those without these characteristics (p < 0.0001 and = 0.04, respectively).

CONCLUSION

Chemerin is associated with endothelial activation and atherosclerosis in RA. Adiposity influences the chemerin-atherosclerotic phenotype relations in RA.

Adiponectin and atherosclerosis in rheumatoid arthritis

In the present study, we examined the potential impact of adiponectin on carotid ultrasound determined atherosclerosis in 210 (119 black and 91 white) RA patients in mixed regression models. Total adiponectin concentrations were smaller in patients with compared to those without the metabolic syndrome (MetS) defined waist criterion (median (range) = 6.47 (1.23–34.54) versus 8.38 (0.82–85.30) ng/mL, P = 0.02, resp.); both total and high molecular weight (HMW) adiponectin concentrations were larger in patients with compared to those without joint deformities (7.97 (0.82–85.30) and 3.51 (0.01–35.40) versus 5.36 (1.29–19.49) and 2.34 (0.01–19.49) ng/mL, P = 0.003 and 0.02, resp.). Total and HMW adiponectin concentrations were associated with carotid artery plaque in patients with MetS waist (odds ratio (95% CI) = 0.87 (0.76–0.99) and 0.92 (0.85–0.99) per 1-standard deviation increment, P = 0.02 for both) and those without joint deformities (odds ratio (95% CI) = 0.94 (0.88–0.99) and 0.94 (0.89–0.99), P = 0.03 for both). Plaque prevalence was lower in patients without compared to those with joint deformities (23.4% versus 42.6, P = 0.004 in multivariable analysis). In RA patients with abdominal obesity or no clinically evident joint damage, adiponectin concentrations are reduced but nevertheless associated with decreased carotid atherosclerosis.

Retinol binding protein 4 concentrations relate to enhanced atherosclerosis in obese patients with rheumatoid arthritis

Background

Retinol binding protein 4 (RBP) enhances metabolic risk and atherogenesis. Whether RBP4 contributes to cardiovascular risk in rheumatoid arthritis (RA) is unknown.

Methods

We assessed RBP4 concentrations and those of endothelial activation molecules including E-selectin, vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 by ELISA, and the common carotid artery intima-media thickness (cIMT) and carotid artery plaque by ultrasound in 217 (112 black and 105 white) patients with RA. Relationships were identified in potential confounder and mediator adjusted mixed regression models.

Results

RBP4 concentrations were associated with systolic and mean blood pressure, and those of glucose and E-selectin (partial R = −0.207 (p = 0.003), −0.195 (p = 0.006), −0.155 (p = 0.03) and −0.191 (p = 0.007), respectively in all patients); these RBP4-cardiovascular risk relations were mostly reproduced in patients with but not without adverse traditional or non-traditional cardiovascular risk profiles. RBP4 concentrations were not associated with atherosclerosis in all patients, but related independently to cIMT (partial R = 0.297, p = 0.03) and plaque (OR (95%CI) = 2.95 (1.31–6.68), p = 0.008) in those with generalized obesity, as well as with plaque in those with abdominal obesity (OR (95%CI) = 1.95 (1.12–3.42), p = 0.01).

Conclusion

In the present study, RBP4 concentrations were inversely associated with metabolic risk and endothelial activation in RA. This requires further investigation. RBP4 concentrations were related to enhanced atherosclerosis in patients with generalized or/and abdominal obesity.