Weight change during pharmacological blockade of interleukin-6 or tumor necrosis factor-α in patients with inflammatory rheumatic disorders: a 16-week comparative study

Changes in metabolic parameters and serum YKL-40 levels in Chinese rheumatoid arthritis patients during tocilizumab therapy

OBJECTIVE

To investigate the metabolic changes during therapy of tocilizumab (TCZ) and methotrexate (MTX) in non-diabetic rheumatoid arthritis (RA) patients and for the first time explore the associations between metabolic parameters and serum YKL-40 (sYKL-40) levels.

METHODS

We enrolled active non-diabetic RA patients who were refractory to MTX. Patients received intravenous TCZ (8 mg/kg) once every 4 weeks combined with MTX for 24 weeks. Metabolic parameters and sYKL-40 levels were measured before TCZ infusion at baseline, week 4, week 12, and week 24. Correlations were assessed by the Spearman's rank correlation analysis.

RESULTS

A total of 91 non-diabetic RA patients were enrolled in this study. At week 24, we observed a significant elevation in body mass index (BMI), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) levels. In contrast, there was a significant decrease in TC/HDL‑C ratio. No apparent changes in insulin resistance were found. Additionally, we detected a significant reduction in sYKL-40 levels during the study. At week 24, changes in sYKL-40 levels showed a significant negative correlation (r = -0.334, p = 0.002) with changes in TC levels.

CONCLUSION

The combined therapy of TCZ and MTX resulted in a significant increase in BMI and lipid levels, while an evident decrease in the TC/HDL‑C ratio and sYKL-40 levels in RA patients. Additionally, there was a significant correlation between the decrease in sYKL-40 levels and the increase in TC levels during treatment with TCZ and MTX. Key Points • Lipid levels elevated significantly and sYKL-40 levels decreased obviously after therapy of TCZ combined with MTX in Chinese RA patients. • There was a significant correlation between the increase in TC levels and the decrease in sYKL-40 levels during treatment with TCZ and MTX in RA patients.

Colorable role of interleukin (IL)-6 in obesity hypertension: A hint from a Chinese adult case-control study

BACKGROUND

Obesity and hypertension are major risk factors for cardiovascular diseases that affect millions of people worldwide. Both conditions are associated with chronic low-grade inflammation, which is mediated by cytokines such as interleukin-6 (IL-6). IL-6 is a multifunctional cytokine that can have pro-inflammatory or anti-inflammatory effects depending on the context. The exact role of IL-6 in obesity-associated hypertension is unclear.

OBJECTIVE

To investigate how IL-6 affects blood pressure, inflammation, and metabolic function in obesity-hypertension using a Chinese adult case-control study.

METHODS

A total of 153 participants were sorted into four subgroups according to their body mass index (BMI) and blood pressure (BP): normal healthy group (NH), just obesity group (JO), just-hypertension group (JH), and obesity-hypertension group (OH). Serum IL-6 concentrations were measured by Enzyme-linked Immunosorbent Assay (ELISA) and their correlations with anthropometric and laboratory parameters and their differences across the subgroups were examined. Multiple linear regression analysis was performed to identify the predictors of serum IL-6 concentrations in each group.

RESULTS

Serum IL-6 concentrations were higher in NH group than in JO group and correlated positively with diastolic blood pressure in NH and JO groups, but not in JH and OH groups. Serum IL-6 concentrations also correlated with albumin in NH group, alkaline phosphatase in JO group, serum creatinine and fasting blood glucose in JH group. The influencing factors of serum IL-6 concentrations varied among the four groups, with gender, diastolic blood pressure and albumin being significant predictors in NH group, alkaline phosphatase in JO group, age and serum creatinine in JH group, and none in OH group.

CONCLUSIONS

These results suggest that IL-6 may play diverse effects in the pathogenesis of obesity- hypertension, depending on the presence or absence of obesity and hypertension. Further studies are needed to elucidate the underlying mechanisms of IL-6 signaling and function in these diseases.

Roles of inflammation in intrinsic pathophysiology and antipsychotic drug-induced metabolic disturbances of schizophrenia

Schizophrenia is a debilitating psychiatric illness that remains poorly understood. While the bulk of symptomatology has classically been associated with disrupted brain functioning, accumulating evidence demonstrates that schizophrenia is characterized by systemic inflammation and disturbances in metabolism. Indeed, metabolic disease is a major determinant of the high mortality rate associated with schizophrenia. Antipsychotic drugs (APDs) have revolutionized management of psychosis, making it possible to rapidly control psychotic symptoms. This has ultimately reduced relapse rates of psychotic episodes and improved overall quality of life for people with schizophrenia. However, long-term APD use has also been associated with significant metabolic disturbances including weight gain, dysglycemia, and worsening of the underlying cardiometabolic disease intrinsic to schizophrenia. While the mechanisms for these intrinsic and medication-induced metabolic effects remain unclear, inflammation appears to play a key role. Here, we review the evidence for roles of inflammatory mechanisms in the disease features of schizophrenia and how these mechanisms interact with APD treatment. We also discuss the effects of common inflammatory mediators on metabolic disease. Then, we review the evidence of intrinsic and APD-mediated effects on systemic inflammation in schizophrenia. Finally, we speculate about possible treatment strategies. Developing an improved understanding of inflammatory processes in schizophrenia may therefore introduce new, more effective options for treating not only schizophrenia but also primary metabolic disorders.

Effects of IL-6 Signaling Pathway Inhibition on Weight and BMI: A Systematic Review and Meta-Analysis

Inhibitors of the IL-6 signaling pathway, such as tocilizumab, are frequently administered for the treatment of immune diseases, e.g., rheumatoid arthritis and multicentric Castleman's disease. The aim of this systematic review and meta-analysis was to ascertain the effects of IL-6 pathway inhibitors on weight and body mass index (BMI). Using PRISMA guidelines, we systematically reviewed relevant articles from three databases (PubMed, OVID, EMBASE). A random effects model was used to estimate standardized mean change (SMCC). Ten studies with a total of 1531 patients were included in the meta-analysis for weight and ten studies with a total of 1537 patients were included in the BMI meta-analysis. The most commonly administered IL-6 pathway inhibitor was tocilizumab. IL-6 pathway inhibitors were associated with increases in weight (SMCC = 0.09, p = 0.016, 95% CI [0.03, 0.14]) and BMI (SMCC = 0.10, p = 0.0001, 95% CI [0.05, 0.15]). These findings suggest that the IL-6 pathway is involved in weight regulation. Modulating IL-6 signaling may be a potential future therapeutic avenue used as an adjunct for the treatment of disorders associated with weight changes, such as cancer cachexia and anorexia nervosa.

Impact of TNF-α Inhibitors on Body Weight and BMI: A Systematic Review and Meta-Analysis

Objective

The aim of this systematic review and meta-analysis of longitudinal studies was to ascertain to effects of TNF-α inhibitor therapy on body weight and BMI.

Methods

Three databases (PubMed, OVID, and EMBASE) were systematically searched from inception to August 2018. We identified prospective, retrospective, and randomized controlled studies in adults with immune-mediated inflammatory diseases treated with TNF-α inhibitors based on pre-specified inclusion criteria. A random-effects model was used to estimate standardised mean change (SMCC).

Results

Twenty-six longitudinal studies with a total of 1,245 participants were included in the meta-analysis. We found evidence for a small increase in body weight (SMCC = 0.24, p = .0006, 95% CI [0.10, 0.37]) and in BMI (SMCC = 0.26, p < .0001, 95% CI [0.13, 0.39]). On average, patients gained 0.90kg (SD = 5.13) under infliximab, 2.34kg (D = 5.65) under etanercept and 2.27kg (SD = 4.69) during treatment with adalimumab within the duration of the respective studies (4–104 weeks).

Conclusion

Our results yield further support the for the view that TNF-α inhibitors increase body weight and BMI as a potential side effect. Modulating cytokine signaling could be a future therapeutic mechanism to treat disorders associated with weight changes such as anorexia nervosa.

The Interrelations between Biological and Targeted Synthetic Agents Used in Inflammatory Joint Diseases, and Obesity or Body Composition

Obesity is a comorbidity that plays a role in the development and severity of inflammatory joint diseases, including rheumatoid arthritis, psoriatic arthritis and axial spondyloarthritis. The relationships between obesity and adipose tissue and the treatments given for inflammatory joint diseases are bidirectional. In fact, biological agents (bDMARDs) and targeted synthetic agents (tsDMARDs) may influence body weight and body composition of treated patients, while obesity in turn may influence clinical response to these agents. Obesity is a prevalent comorbidity mainly affecting patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA) with specific phenotypes. Tumour necrosis factor alpha (TNFα) inhibitors have been associated with changes in body composition by improving lean mass, but also by significantly increasing fat mass, which localized toward the abdominal/visceral region. The IL-6 inhibitor tocilizumab is associated with an increase in lean mass without change in fat mass. The clinical response to TNFα inhibitors is attenuated by obesity, an effect that is less pronounced with IL-6 inhibitors and the B-cell depletion agent rituximab. Conversely, body weight has no influence on the response to the costimulation inhibitor abatacept. These effects may be of help to the physician in personalized medicine, and may guide the therapeutic choice in obese/overweight patients.

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.

Feedback regulation of Arid5a and Ppar-γ2 maintains adipose tissue homeostasis

Immune cells infiltrate adipose tissues and provide a framework to regulate energy homeostasis. However, the precise underlying mechanisms and signaling by which the immune system regulates energy homeostasis in metabolic tissues remain poorly understood. Here, we show that the AT-rich interactive domain 5A (Arid5a), a cytokine-induced nucleic acid binding protein, is important for the maintenance of adipose tissue homeostasis. Long-term deficiency of Arid5a in mice results in adult-onset severe obesity. In contrast, transgenic mice overexpressing Arid5a are highly resistant to high-fat diet-induced obesity. Inhibition of Arid5a facilitates the in vitro differentiation of 3T3-L1 cells and fibroblasts to adipocytes, whereas its induction substantially inhibits their differentiation. Molecular studies reveal that Arid5a represses the transcription of peroxisome proliferator activated receptor gamma 2 (Ppar-γ2) due to which, in the absence of Arid5a, Ppar-γ2 is persistently expressed in fibroblasts. This phenomenon is accompanied by enhanced fatty acid uptake in Arid5a-deficient cells, which shifts metabolic homeostasis toward prolipid metabolism. Furthermore, we show that Arid5a and Ppar-γ2 are dynamically counterregulated by each other, hence maintaining adipogenic homeostasis. Thus, we show that Arid5a is an important negative regulator of energy metabolism and can be a potential target for metabolic disorders.

Body Mass Index and Clinical Response to Tocilizumab in Patients With Rheumatoid Arthritis

Objectives

This study aims to determine whether baseline body mass index (BMI) affects clinical response to tocilizumab (TCZ) after six months of treatment in rheumatoid arthritis (RA) patients.

Patients and methods

In this prospective study, a total of 52 RA patients (10 males, 42 females; mean age 50.6±12.2 years; range, 23 to 73 years) receiving intravenous TCZ were consecutively recruited and followed-up for six months. BMI was calculated before initiation of TCZ treatment. The primary clinical response criterion was clinical disease activity index (CDAI) low disease activity (LDA) and the secondary clinical response criteria included CDAI remission, disease activity score based on 28 joints (DAS28)-erythrocyte sedimentation rate (ESR) LDA, DAS28-ESR remission, European League Against Rheumatism (EULAR) good response, and decreased DAS28-ESR (ΔDAS28-ESR)≥1.2.

Results

The number of RA patients classified as normal weight, overweight, and obese according to baseline BMI was 38 (73.1%), eight (15.4%), and six (11.5%), respectively. Similar baseline BMI median levels were found between RA patients reaching CDAI LDA and non-LDA: 21.11 (18.94-23.72) versus 20.78 (20.03-22.29) (p=0.98), and non-significant difference in the proportion of responders between normal weight and overweight/obese RA patients was found (p=0.47). No significant difference was found when the secondary clinical response criteria were applied.

Conclusion

Our study demonstrates that BMI is not associated with clinical response to TCZ among RA patients and TCZ may be used to treat RA patients regardless of BMI levels.

Interleukin-6 released from differentiating human beige adipocytes improves browning

Brown and beige adipocytes contribute significantly to the regulation of whole body energy expenditure and systemic metabolic homeostasis not exclusively by thermogenesis through mitochondrial uncoupling. Several studies have provided evidence in rodents that brown and beige adipocytes produce a set of adipokines ("batokines") which regulate local tissue homeostasis and have beneficial effects on physiological functions of the entire body. We observed elevated secretion of Interleukin (IL)-6, IL-8 and monocyte chemoattractant protein (MCP)-1, but not tumor necrosis factor alpha (TNFα) or IL-1β pro-inflammatory cytokines, by ex vivo differentiating human beige adipocytes (induced by either PPARγ agonist or irisin) compared to white. Higher levels of IL-6, IL-8 and MCP-1 were released from human deep neck adipose tissue biopsies (enriched in browning cells) than from subcutaneous ones. IL-6 was produced in a sustained manner and mostly by the adipocytes and not by the undifferentiated progenitors. Continuous blocking of IL-6 receptor by specific antibody during beige differentiation resulted in downregulation of brown marker genes and increased morphological changes that are characteristic of white adipocytes. The data suggest that beige adipocytes adjust their production of IL-6 to reach an optimal level for differentiation in the medium enhancing browning in an autocrine manner.

Changes in body composition and metabolic profile during interleukin 6 inhibition in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by increased mortality associated with cardiometabolic disorders including dyslipidaemia, insulin resistance, and cachectic obesity. Tumour necrosis factor inhibitors and interleukin 6 receptor blocker licensed for the treatment of RA decrease inflammation and could thus improve cardiovascular risk, but their effects on body composition and metabolic profile need to be clarified. We investigated the effects of tocilizumab (TCZ), a humanized anti-interleukin 6 receptor antibody, on body composition and metabolic profile in patients treated for RA.

METHODS

Twenty-one active RA patients treated with TCZ were included in a 1 year open follow-up study. Waist circumference, body mass index, blood pressure, lipid profile, fasting glucose, insulin, serum levels of adipokines and pancreatic/gastrointestinal hormones, and body composition (dual-energy X-ray absorptiometry) were measured at baseline and 6 and 12 months of treatment. At baseline, RA patients were compared with 21 non-RA controls matched for age, sex, body mass index, and metabolic syndrome.

RESULTS

Compared with controls, body composition was altered in RA with a decrease in total and appendicular lean mass, whereas fat composition was not modified. Among RA patients, 28.6% had a skeletal muscle mass index below the cut-off point for sarcopaenia (4.8% of controls). After 1 year of treatment with TCZ, there was a significant weight gain without changes for fat mass. In contrast, an increase in lean mass was observed with a significant gain in appendicular lean mass and skeletal muscle mass index between 6 and 12 months. Distribution of the fat was modified with a decrease in trunk/peripheral fat ratio and an increase in subcutaneous adipose tissue. No changes for waist circumference, blood pressure, fasting glucose, and atherogenic index were observed.

CONCLUSIONS

Despite weight gain during treatment with TCZ, no increase in fat but a modification in fat distribution was observed. In contrast, muscle gain suggests that blocking IL-6 might be efficient in treating sarcopaenia associated with RA.

Regulation of energy balance by inflammation: common theme in physiology and pathology

Inflammation regulates energy metabolism in both physiological and pathological conditions. Pro-inflammatory cytokines involves in energy regulation in several conditions, such as obesity, aging (calorie restriction), sports (exercise), and cancer (cachexia). Here, we introduce a view of integrative physiology to understand pro-inflammatory cytokines in the control of energy expenditure. In obesity, chronic inflammation is derived from energy surplus that induces adipose tissue expansion and adipose tissue hypoxia. In addition to the detrimental effect on insulin sensitivity, pro-inflammatory cytokines also stimulate energy expenditure and facilitate adipose tissue remodeling. In caloric restriction (CR), inflammatory status is decreased by low energy intake that results in less energy supply to immune cells to favor energy saving under caloric restriction. During physical exercise, inflammatory status is elevated due to muscle production of pro-inflammatory cytokines, which promote fatty acid mobilization from adipose tissue to meet the muscle energy demand. In cancer cachexia, chronic inflammation is elevated by the immune response in the fight against cancer. The energy expenditure from chronic inflammation contributes to weight loss. Immune tolerant cancer cells gains more nutrients during the inflammation. In these conditions, inflammation coordinates energy distribution and energy demand between tissues. If the body lacks response to the pro-inflammatory cytokines (Inflammation Resistance), the energy metabolism will be impaired leading to an increased risk for obesity. In contrast, super-induction of the inflammation activity leads to weight loss and malnutrition in cancer cachexia. In summary, inflammation is a critical component in the maintenance of energy balance in the body. Literature is reviewed in above fields to support this view.

Response to tocilizumab in rheumatoid arthritis is not influenced by the body mass index of the patient

OBJECTIVE

To assess the relationship between the body mass index (BMI) and the efficacy of tocilizumab (TCZ) in patients with rheumatoid arthritis (RA).

METHODS

We conducted a retrospective study in 222 patients with RA followed by 5 centers. The European League Against Rheumatism response was evaluated at 6 months. Univariate and multivariate logistic regressions were performed.

RESULTS

No significant association between the BMI and the response to TCZ at 6 months was found after adjustment for potential confounding factors (adjusted OR 0.45, 95% CI 0.16-1.24, p = 0.13 and OR 1.19, 95% CI 0.31-4.48, p = 0.78 for BMI 25-30 kg/m(2) and BMI > 30 kg/m(2), respectively, compared to BMI < 25 kg/m(2)).

CONCLUSION

Response to TCZ in patients with RA is not influenced by the baseline BMI, in contrast to anti-tumor necrosis factor drugs.

Obesity, adipokines and neuroinflammation

Global levels of obesity are reaching epidemic proportions, leading to a dramatic increase in incidence of secondary diseases and the significant economic burden associated with their treatment. These comorbidities include diabetes, cardiovascular disease, and some psychopathologies, which have been linked to a low-grade inflammatory state. Obese individuals exhibit an increase in circulating inflammatory mediators implicated as the underlying cause of these comorbidities. A number of these molecules are also manufactured and released by white adipose tissue (WAT), in direct proportion to tissue mass and are collectively known as adipokines. In the current review we focused on the role of two of the better-studied members of this family namely, leptin and adiponectin, with particular emphasis on their role in neuro-immune interactions, neuroinflammation and subsequent brain diseases. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'.

Clinical experience of IL-6 blockade in rheumatic diseases - implications on IL-6 biology and disease pathogenesis

Interleukin 6 (IL-6) plays a significant role in many rheumatological diseases and has been described as both a pro- and anti-inflammatory cytokine. IL-6 blockade has been investigated in various rheumatic diseases and a humanised anti-IL-6 receptor antibody has been licensed for use in rheumatoid arthritis, systemic and polyarticular juvenile idiopathic arthritis. The increasing clinical experience of IL-6 blockade in rheumatic diseases adds to the existing knowledge regarding the physiological and pathological roles of IL-6.

Metabolic inflammation: role of cytokines in the crosstalk between adipose tissue and liver

The innate immune system and its major mediators, i.e., cytokines, are increasingly recognized as being of crucial importance in metabolic inflammation as observed in morbid obesity and type 2 diabetes (T2D). Morbid obesity is commonly associated with adipose tissue inflammation. Adipose tissue inflammation is characterized by an increased expression of various pro-inflammatory cytokines such as tumor necrosis factor-alpha, interleukin-1 and -6, and by a rather heterogenous cellular infiltrate including monocytes/macrophages, neutrophils, B lymphocytes, T lymphocytes, and others. It has been demonstrated that in patients with severe obesity and fatty liver disease, expression of these pro-inflammatory cytokines in adipose tissue is 100-1000 times higher compared with that in the liver. Therefore, the adipose tissue can be considered in the state of severe obesity as the "cytokine factory" of the body. Rapid weight loss almost entirely eliminates pro-inflammatory cytokines in the adipose tissue, and therefore provides a very potent anti-inflammatory strategy. In conclusion, there is increasing evidence that peripheral tissues such as the adipose tissue may affect disease processes in target organs such as the liver, pancreas, heart, or blood vessels, and may therefore significantly contribute to chronic inflammation as observed in obesity and T2D.