Insulin resistance and levels of adipokines in patients with untreated early rheumatoid arthritis

Metabolic Consequences of Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA) may have metabolic disruption, which can contribute to adverse long-term outcomes, for multiple reasons. Patients with RA appear to have a higher risk of sarcopenia, type 1 and type 2 diabetes mellitus, metabolic syndrome, and hypertension. Systemic inflammation in RA can cause a "lipid paradox," with reduced low-density lipoprotein being associated with higher rates of cardiovascular disease. In this review, we discuss changes to body composition, insulin resistance, lipids, and blood pressure that often occur in patients with RA. We examine the current understanding of the mechanisms underlying disruptions in metabolic pathways in RA, their clinical effects, and how treatment affects these changes.

Insulin resistance and adverse lipid profile in untreated very early rheumatoid arthritis patients: A single-center, cross-sectional study in China

Objectives

This study aims to evaluate the presence and factors related to insulin resistance (IR) in untreated very early rheumatoid arthritis (RA) patients.

Patients and methods

Between June 2020 and July 2021, a total of 90 RA patients (29 males, 61 females; mean age: 49.3±10.2 years; range 24 to 68 years) and 90 age-, sex- and body mass index (BMI)-matched controls (35 males, 55 females; mean age: 48.3±5.1 years; range 38 to 62 years) were included. Homeostatic model assessment was applied to evaluate IR (HOMA-IR) and β-cell function (HOMA-β). Disease activity score 28 (DAS28) was used to estimate disease activity. Lipid profile, hemoglobin A1c (HbA1c), glucose, insulin, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were measured. Logistic regression analysis was performed to investigate the relationship between the IR and clinical features of RA patients.

Results

The RA patients had higher HOMA-IR values (p<0.001) and adverse lipid profile. The IR was positively correlated with age (r=0.35, p<0.01), CRP (r=0.42, p<0.001), ESR (r=0.33, p<0.01), disease duration (r=0.28, p<0.01), and DAS28 (r=0.50, p<0.001). The DAS28, CRP and age, but not sex and menopausal status, were independently associated with IR.

Conclusion

Insulin resistance was present in untreated very early RA patients. The DAS28, CRP, and age were independent predictors for the presence of IR. Based on these findings, RA patients should be evaluated early for the presence of IR to reduce the risk of metabolic diseases.

Evaluation of the adipokine profile (adiponectin, resistin, adipsin, vaspin, and leptin) in patients with early rheumatoid arthritis and its correlation with disease activity

Introduction

Adipokines may play a role in the early stages of rheumatoid arthritis. This study evaluated the performance of adipokines in a Colombian population with early rheumatoid arthritis and its relationship with disease activity.

Material and methods

A cross-sectional study evaluated serum adipokine levels (adiponectin, resistin, adipsin, vaspin, and leptin) in patients with early rheumatoid arthritis (eRA), evaluating demographic and clinical variables, along with a control group matched by age and gender. A factorial analysis was performed using principal components analysis (PCA), and a Spearman correlation analysis was performed. Similarly, a cut-off point for serum levels is proposed based on the receiver operating characteristic (ROC) curve between eRA and controls and sensitivity analysis.

Results

Fifty-one eRA subjects were included; there were 41 women. The body mass index (BMI) was 25.12 ±3.8. A statistically significant correlation was identified between adipsin, BMI, and RAPID3. Vaspin and leptin were correlated with BMI. Resistin levels were higher in patients with RAPID3 near remission (p = 0.041), and adiponectin, vaspin, and leptin levels were lower in patients with DAS28 ESR in remission (p = 0.033, p = 0.012, and p = 0.017, respectively). Principal components analysis in component 1 adipokines as adipsin and leptin with BMI and RAPID3 as disease activity index are grouped. Moreover, component 2 had a strong relation between ESR and CRP with an inverse correlation with cholesterol levels and vaspin. A cut-off point was established for each adipokine, thus identifying the best performance for leptin levels greater than 0.58 ng/ml with a sensitivity of 76.5% and specificity of 74.5%.

Conclusions

Adipokine levels are relevant in eRA, especially with disease activity indexes. Resistin levels were higher in patients with an activity index near remission. Otherwise, adiponectin, vaspin, and leptin levels were lower in patients with low activity indexes. RAPID3 correlated with adipsin. It is complementary to the previously published analysis of adipokines.

Metabolic Syndrome, Disease Activity, and Adipokines in Patients With Newly Diagnosed Inflammatory Joint Diseases

OBJECTIVE

To investigate metabolic syndrome (MetS), disease activity, and adipokine levels among patients with rheumatoid arthritis (RA), spondyloarthritis (SpA), and undifferentiated arthritis (UA) at the time of diagnosis and after 1 year of follow-up.

METHODS

Patients with inflammatory joint diseases participating in the Northern Savo 2010 population-based longitudinal epidemiological study were evaluated for components of MetS (by National Cholesterol Education Program's Adult Treatment Panel III) and clinical parameters of disease activity. The adipokines adiponectin, adipsin, resistin, and leptin were measured at baseline and after 1 year of treatment with disease-modifying antirheumatic drugs.

RESULTS

Among 176 patients, MetS was detected in 42% of RA, 36% of SpA, and 51% of UA patients. Metabolic syndrome was associated with higher disease activity as measured by patient global assessment in RA and UA patients and increased pain in RA patients. Leptin levels were increased in patients with MetS, showing a linearly increasing trend with the number of components of MetS in SpA and UA, but not in RA. In RA patients, decrease in disease activity correlated with decrease in leptin levels. Resistin did not associate with MetS, but a decrease in resistin correlated with decrease in disease activity in RA and UA. In SpA, increased adiponectin level correlated with relief in disease activity, but not with MetS.

CONCLUSIONS

Metabolic syndrome was common in patients with newly diagnosed arthritides and associated with higher disease activity and increased leptin levels. Resistin responded to treatment of arthritis in RA and UA, leptin in RA, and adiponectin in SpA.

Adiponectin Deregulation in Systemic Autoimmune Rheumatic Diseases

Deregulation of adiponectin is found in systemic autoimmune rheumatic diseases (SARDs). Its expression is downregulated by various inflammatory mediators, but paradoxically, elevated serum levels are present in SARDs with high inflammatory components, such as rheumatoid arthritis and systemic lupus erythematosus. Circulating adiponectin is positively associated with radiographic progression in rheumatoid arthritis as well as with cardiovascular risks and lupus nephritis in systemic lupus erythematosus. However, in SARDs with less prominent inflammation, such as systemic sclerosis, adiponectin levels are low and correlate negatively with disease activity. Regulators of adiponectin gene expression (PPAR-γ, Id3, ATF3, and SIRT1) and inflammatory cytokines (interleukin 6 and tumor necrosis factor α) are differentially expressed in SARDs and could therefore influence total adiponectin levels. In addition, anti-inflammatory therapy could also have an impact, as tocilizumab treatment is associated with increased serum adiponectin. However, anti-tumor necrosis factor α treatment does not seem to affect its levels. Our review provides an overview of studies on adiponectin levels in the bloodstream and other biological samples from SARD patients and presents some possible explanations why adiponectin is deregulated in the context of therapy and gene regulation.

Cumulative inflammatory burden and obesity as determinants of insulin resistance in patients with established rheumatoid arthritis: cross-sectional study

OBJECTIVES

To describe the prevalence of insulin resistance (IR) in patients with established rheumatoid arthritis (RA) and to analyse the contribution of cumulative inflammatory burden and other factors to its development.

DESIGN

Observational cross-sectional study.

PARTICIPANTS

Patients with RA and controls matched for age, sex and Body Mass Index. We excluded patients with diabetes.

SETTINGS

Patients from an RA inception cohort at Hospital Regional Universitario de Málaga, Spain, were recruited between September 2016 and May 2018.

PRIMARY AND SECONDARY OUTCOME MEASURES

IR was evaluated using the homeostasis model assessment for IR and beta-cell function and the quantitative insulin sensitivity check index. Other variables included the cumulative 28-Joint Disease Activity Score (DAS28) with C reactive protein (CRP) body composition and cytokines. Two logistic regression models were constructed to identify factors associated with IR in patients with RA.

RESULTS

Eighty-nine patients with RA and 80 controls were included. The prevalence of IR was similar in both cases and controls. Inflammatory activity was controlled appropriately in patients during follow-up (mean DAS28 3.1 (0.8)). The presence of IR in patients with RA was associated with obesity (OR 6.01, 95% CI 1.9 to 8.7), higher cumulative DAS28-CRP values during follow-up (OR 2.8, 95% CI 1.3 to 6.0), and higher interleukin-1β levels (OR 1.6, 95% CI 1.1 to 2.4). The second model showed that the risk of IR increased by 10% for each kilogram of excess body fat.

CONCLUSION

In patients with well-controlled, established RA, IR is associated mainly with poorer control of inflammation from diagnosis and with obesity, specifically total fat mass.

Association of adipokines with rheumatic disease activity indexes and periodontal disease in patients with early rheumatoid arthritis and their first-degree relatives

OBJECTIVE

To evaluate the adipokine levels in early rheumatoid arthritis (eRA) and first-degree relatives (FDR) of patients with RA and establish their association with rheumatic disease activity and periodontal variables.

METHOD

A cross-sectional study with eRA patients, FDR and a healthy population. Adipokine levels, clinical, joint radiological indexes and periodontal variables were evaluated. A descriptive, bivariate analysis was performed based on the adipokine levels by χ² , Fisher's test and Mann-Whitney U test. A logistic regression was made for associations.

RESULTS

High leptin levels were associated with the diagnosis of eRA (odds ratio [OR] = 2.79; 95% CI 1.54-5.07). Early rheumatoid arthritis with high adiponectin levels was less likely to have Multidimensional Health Assessment Questionnaire score >3, body mass index (BMI) >25 and Routine Assessment of Patient Index Data 3 score >12 (OR = 0.16; 95% CI 0.03-0.72). Early rheumatoid arthritis was more likely to present high leptin and interleukin (IL)6 levels with low adiponectin simultaneously (OR = 5.03; 95% CI 1.05-24.0). High leptin levels were associated with the FDR adjusted for IgG2 Porphyromonas gingivalis, swollen joints, P gingivalis and low IL6 (OR = 2.57; 95% CI 1.14-5.95).

CONCLUSION

High adipokine levels in eRA may modulate the disease activity. Having more than 1 adipokine at high serum levels is associated with increased disability, disease activity and BMI, indicating that RA is controlled by adiponectin levels in the early stages of the disease. High leptin levels, presence of P gingivalis and swollen joints may be the factors associated with the development of RA in FDR.

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.

Fasting triglycerides and glucose index: a useful screening test for assessing insulin resistance in patients diagnosed with rheumatoid arthritis and systemic lupus erythematosus

BACKGROUND

Insulin resistance (IR) is frequently observed in patients with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE). In clinical practice, IR assessment is limited to a low proportion of patients due to cost and equipment and technical expertise requirements. The surrogate index of triglycerides and glucose (TyG index) has been validated in non-rheumatic populations, showing adequate sensitivity and specificity for IR, although this index has not yet been used in connective tissue disorders. The aim of this study was to evaluate the frequency of insulin resistance (IR) using the validated surrogate index of triglycerides and glucose (TyG index) and to explore factors associated with IR in Mexican women with RA or SLE.

METHODS

Ninety-five female RA and 57 SLE patients were included in a cross-sectional study. Clinical and epidemiological variables were evaluated. IR was assessed using the TyG index with a cutoff value of > 4.68. Logistic regression analysis was performed to identify factors associated with IR excluding confounders.

RESULTS

IR frequency in the entire sample was 50%, higher than the 10% observed in non-rheumatic controls (p < 0.001). The frequency of IR was similar in SLE (49.1%) and RA (50.5%, p = 0.8) patients. IR was associated with a longer duration of hypertension and higher total cholesterol and low density lipoprotein cholesterol levels. Based on multivariate analysis, the duration of hypertension (OR: 1.06; 95% CI 1.002-1.12, p = 0.04), waist circumference (OR: 1.04; 95% CI 1.01-1.08, p = 0.007), uric acid levels (OR: 1.46; 95% CI 1.08-1.97, p = 0.01), RA (OR: 4.87; 95% CI 1.31-18.78, p = 0.01) and SLE (OR: 4.22; 95% CI 1.06-16.74, p = 0.04) were the main risk factors for IR.

CONCLUSIONS

This study shows that the TyG index is a useful screening test for IR in RA and SLE patients. Future longitudinal studies should be performed with the aim of identifying the predictive value of TyG index results for identifying complications linked to IR.

Insulin Resistance in Early Rheumatoid Arthritis Is Associated with Low Appendicular Lean Mass

In established rheumatoid arthritis (RA), the presence of insulin resistance (IR) is well proven but, in the early stage of the disease, data are inconclusive. We evaluated the presence of IR and associations with body composition (BC) parameters among early RA (ERA) and control subjects. The study group consisted of 92 ERA and 321 control subjects. Using homeostatic model assessment of IR (HOMA-IR), the cut-off value for IR was 2.15. 56% of the ERA patients and 25% of the controls had IR. Of the BC parameters, patients with early RA had less fat-free mass and appendicular lean mass (ALM). In multivariable model, ERA group (b-Coefficient) (4.8, CI: 2.6-8.8), male gender (7.7, CI: 2.7-22.1), and fat mass index (1.2, CI: 1.1-1.4) were associated with IR. Insulin-resistant ERA patients had higher inflammatory markers and higher disease activity. In the multivariable model in the ERA group, IR was associated with male gender (b-Coefficient) (7.4, CI: 153-34.9), high disease activity (6.2, CI: 1.7-22.2), and lower ALM (0.03, CI: 0.001-0.97). IR develops in the early stage of RA in the majority of patients. IR is more common among males and is associated with RA disease activity and lower ALM.

Abnormal Glucose Metabolism in Rheumatoid Arthritis

The incidence of abnormal glucose metabolism in patients with rheumatoid arthritis was considerably higher than the general population. The persistent systemic inflammatory state in rheumatoid arthritis might be associated with the glucose metabolism dysfunction. In this context, insulin resistance, islet β cell apoptosis, inflammatory cytokines, and other aspects which were linked with abnormal glucose metabolism in rheumatoid arthritis were reviewed. This review will be helpful in understanding the abnormal glucose metabolism mechanism in patients with rheumatoid arthritis and might be conducive to finding an effective treatment.

IL-6 Promotes Islet β-Cell Dysfunction in Rat Collagen-Induced Arthritis

The aim of this study was to explore the possible mechanism of rheumatoid arthritis- (RA-) related abnormal glucose metabolism. The model of collagen-induced arthritis (CIA) was established by intradermal injection of type II collagen into Wistar rats; complete Freund's adjuvant injections were used as the control group. Fasting plasma glucose (FBG) was measured by the glucose oxidase method. Fasting insulin (FIns) and the expressions of IL-6 were detected by ELISA. Islet caspase-3 was examined by immunohistochemistry. On day 17 after immunization, FBG of the CIA group showed an elevated FBG value compared with the control group. Meanwhile, the FIns of group CIA was lower when compared with the control group. Interestingly, the inflammatory cytokine IL-6 expression was significantly increased when compared with the control group. As expected, the abnormal glucose metabolism was accompanied by the increased IL-6 expression. Furthermore, in line with the upregulated IL-6 expression, the apoptosis related enzyme caspase-3 was also markedly increased. These data showed that the elevated FBG in CIA may be associated with the reduced FIns level secondary to the overapoptosis of pancreas islet cells induced by IL-6.