Infliximab and insulin resistance

Relation of Circulating Resistin to Insulin Resistance in Type 2 Diabetes and Obesity: A Systematic Review and Meta-Analysis

Background: Resistin, a cysteine-rich polypeptide encoded by the RETN gene, which plays an important role in many mechanisms in rodent studies, including lipid metabolism, inflammation and insulin resistance. Nevertheless, the relationship between resistin and insulin resistance in humans is under debate. The present study was designed to clarify the correlation between resistin and insulin resistance.

Methods: A systematic literature search was performed using PubMed, Embase and Cochrane Library until March 3, 2019 with the keywords “resistin” and “insulin resistance.” Funnel plots and Egger's test were used to detect publication bias. A random-effects model was used to calculate the pooled effect size. Subgroup analysis and meta regression was performed to identify the sources of heterogeneity.

Results: Fifteen studies were included in our systematic review. Among them, 10 studies with Pearson coefficients were used for meta-analysis. We found resistin levels were weakly correlated with insulin resistance in those with T2DM and obesity (r = 0.21, 95% CI: 0.06–0.35, I² = 59.7%, P = 0.003). Nevertheless, subgroup analysis suggested that circulating resistin levels were significantly positively correlated with insulin resistance in individuals with hyperresistinemia (≥14.8 ng/ml) (r = 0.52, 95% CI: 0.35–0.68, I² = 0.0%, P = 0.513). And there was no relationship between circulating resistin and insulin resistance in those with normal circulating resistin levels (<14.8 ng/ml) (r = 0.08, 95% CI: −0.01–0.18, I² = 0.0%, P = 0.455). Publication bias was insignificant (Egger's test P = 0.592).

Conclusion: In T2DM and obese individuals, resistin levels were positively correlated with insulin resistance in those with hyperresistinemia, but not in those with normal circulating resistin levels.

The effect of non-TNF-targeted biologics and small molecules on insulin resistance in inflammatory arthritis

Inflammatory arthritides are chronic diseases characterised by an increase in cardiovascular risk, largely attributable to the synergy between high-grade systemic inflammation and an elevated prevalence of traditional cardiovascular risk factors. Amongst the latter, insulin resistance and type 2 diabetes (T2D) play a key position. Previous studies demonstrated a potential insulin-sensitizing effect of anti-TNF biologic medications. For converse, less is known about the role of newer biologics or small molecules. For this reason, we performed a systematic review of the literature in order to identify the available data on the effect on insulin resistance of non-TNF targeting biologics and small molecules approved for the treatment of inflammatory arthritides. The search strategy initially retrieved 486 records of which only 10 articles were selected for inclusion in the final review. According to the available evidence, some of the newest molecules, in particular tocilizumab and abatacept, may have a role in improving insulin sensitivity; for converse, anakinra-mediated effect on glucose metabolism may exploit different facets of T2D pathophysiology, such as the preservation of beta-cell function. However, the data available on this issue are largely inconsistent and future, adequately designed studies are still needed to clarify the differential impact of novel therapeutics on individual pathophysiological features of T2D and other emerging cardiovascular risk factors.

Prevalence of diabetes and unrecognized diabetes in hypertensive patients aged 40 to 79 years in southwest China

This study aimed to assess the prevalence of diabetes and unrecognized diabetes in hypertensive patients aged 40 to 79 years in Southwest China. From September 2013 to March 2014, a cross-sectional survey was conducted in 4021 hypertensive patients aged 40 to 79 years living in Chengdu and Chongqing, China. Fasting plasma glucose (FPG) and 2h plasma glucose (2-hPG) in an oral glucose-tolerance test (OGTT) were used for assessments. Whether the patients previously had diabetes (DM) was determined by their own reports. The survey was carried out by the same questionnaire for all respondents. DM prevalence was 32.0% in hypertensive patients aged 40 to 79 years in Southwest China, with the rates of 29.6% and 33.5% in men and women, respectively (P<0.001). DM prevalence increased with age age and body-mass index. DM prevalence rates were 16.9%, 24.7%, 38.2% and 41.9% in hypertensive patients aged 40-49, 50-59, 60-69 and over 70, respectively. DM prevalence were 30.6%, 27.9%, 37.1%, and 37.4%, for BMI<18.5, 18.5-24.9, 25.0-29.9, and ≥30, respectively. Prevalence of unrecognized DM were 20.8% in hypertensive patients aged 40 to 79 years in Southwest China. Using only fasting blood glucose testing without OGTT would have resulted in 65.0% of missed DM diagnosis in these newly diagnosed patients. The prevalence of DM and unrecognized DM were high in hypertensive patients aged 40 to 79 years in Southwest China.These findings indicate that hypertensive patients aged 40 to 79 years should regularly submit to community-based OGTT screening for timely DM diagnosis.

Complement C3 Is the Strongest Predictor of Whole-Body Insulin Sensitivity in Psoriatic Arthritis

Objectives

To evaluate the correlation between inflammatory measures and whole-body insulin sensitivity in psoriatic arthritis (PsA) patients.

Methods

For the present study, 40 nondiabetic PsA patients were recruited. A standard oral glucose tolerance test (OGTT) was performed. The insulin sensitivity index (ISI), insulinogenic index (IGI) and oral disposition index (ODI) were calculated from dynamic values of glucose and insulin obtained during OGTT.

Results

In our study population, mean ISI was 3.5 ± 2.5, median IGI was 1.2 (0.7–1.8), mean ODI 4.5 ± 4.5. In univariate correlation analysis, ISI correlated inversely with systolic blood pressure (sBP) (R = -0.52, p = 0.001), diastolic blood pressure (dBP) (R = -0.45, p = 0.004) and complement C3 (R = -0.43, p = 0.006) and ODI correlated inversely with sBP (R = -0.38, p = 0.02), dBP (R = -0.35, p = 0.03) and complement C3 (R = -0.37, p = 0.02). No significant correlations were found between analyzed variables and IGI. In a stepwise multiple regression, only complement C3 entered in the regression equation and accounted for approximately 50% of the variance of ISI. Using a receiver operating characteristic (ROC) curve we identified the best cut-off for complement C3 of 1.32 g/L that yielded a sensitivity of 56% and a specificity of 96% for classification of insulin resistant patients.

Conclusions

In conclusion, our data suggest that serum complement C3 could represent a useful marker of whole-body insulin sensitivity in PsA patients.

Prevalence of Undiagnosed Diabetes in Rheumatoid Arthritis: an OGTT Study

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by an excess of cardiovascular disease (CVD) risk, estimated to be at least 50% greater when compared to the general population. Although the widespread diffusion of type 2 diabetes mellitus (T2DM) awareness, there is still a significant proportion of patients with T2DM that remain undiagnosed. Aim of this cross-sectional study was to evaluate the prevalence of undiagnosed diabetes and prediabetes in RA patients. For the present study, 100 consecutive nondiabetic RA patients were recruited. Age- and sex-matched subjects with noninflammatory diseases (osteoarthritis or fibromyalgia) were used as controls. After overnight fasting, blood samples were obtained for laboratory evaluation including serum glucose, total cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglycerides, uric acid, erythrocyte sedimentation rate (ESR), high sensitivity C-reactive protein (hs-CRP), rheumatoid factor (RF), and anti-Cyclic Citrullinated Peptide Antibodies (ACPA). A standard Oral Glucose Tolerance Test (OGTT) with 75 g of glucose was performed and blood samples were collected at time 0, 30, 60, 90, and 120 minutes, for measurement of plasma glucose concentrations. The prevalence of impaired fasting glucose (IFG) (9/100 vs 12/100, P = 0.49), impaired glucose tolerance (IGT) (19/100 vs 12/100, P = 0.17), and concomitant IFG/IGT (5/100 vs 9/100, P = 0.27) was similar between groups, whereas the prevalence of diabetes was significantly higher in RA patients (10/100 vs 2/100, P = 0.02). In a logistic regression analysis, increasing age (OR = 1.13, 95% CI 1.028-1.245, P = 0.01) and disease duration (OR = 1.90, 95% CI 1.210-2.995, P = 0.005) were both associated with an increased likelihood of being classified as prediabetes (i.e. IFG and/or IGT) or T2DM. A ROC curve was built to evaluate the predictivity of disease duration on the likelihood of being diagnosed with T2DM. The area under the ROC curve was 0.67 (95% CI: 0.56-0.78, P = 0.004). We identified the best cut-off of 33 months that yielded a sensitivity of 61% and a specificity of 70% for classification of T2DM patients. According to our data, RA seems to be characterized by an elevated prevalence of undiagnosed diabetes, especially in patients with longer disease duration.

Adipose tissue inflammation in the pathogenesis of type 2 diabetes

At least 2.8 million people die each year as a result of being overweight or obese, and the biggest burden being obesity-related diseases. Overweight and obesity account for a major proportion of type 2 diabetes (T2D) cases. Obesity is associated with inflammation in adipose tissue, namely an infiltration and expansion of macrophages, which produce inflammatory cytokines that interfere with insulin signaling, and a loss of protective cells that promote adipose homeostasis. Thus, it is now clear that inflammation is an underlying cause or contributor to T2D as well as many other obesity-induced diseases, including atherosclerosis and cancer. Inflammatory pathways contribute to impaired glucose handling by adipocytes, hepatocytes, and muscle cells and interfere with insulin production and insulin signaling. This review highlights the roles of the different immune populations in lean adipose tissue and their importance in tissue homeostasis to keep inflammation at bay. We also discuss the changes that occur in these immune cells during the development of obesity, which has detrimental effects on the health of adipose tissue, and local and systemic insulin resistance.

Central obesity, type 2 diabetes and insulin: exploring a pathway full of thorns

The prevalence of type 2 diabetes (T2D) is rapidly increasing. This is strongly related to the contemporary lifestyle changes that have resulted in increased rates of overweight individuals and obesity. Central (intra-abdominal) obesity is observed in the majority of patients with T2D. It is associated with insulin resistance, mainly at the level of skeletal muscle, adipose tissue and liver. The discovery of macrophage infiltration in the abdominal adipose tissue and the unbalanced production of adipocyte cytokines (adipokines) was an essential step towards novel research perspectives for a better understanding of the molecular mechanisms governing the development of insulin resistance. Furthermore, in an obese state, the increased cellular uptake of non-esterified fatty acids is exacerbated without any subsequent β-oxidation. This in turn contributes to the accumulation of intermediate lipid metabolites that cause defects in the insulin signaling pathway. This paper examines the possible cellular mechanisms that connect central obesity with defects in the insulin pathway. It discusses the discrepancies observed from studies organized in cell cultures, animal models and humans. Finally, it emphasizes the need for therapeutic strategies in order to achieve weight reduction in overweight and obese patients with T2D.

Abatacept improves whole-body insulin sensitivity in rheumatoid arthritis: an observational study

Rheumatoid arthritis (RA) is characterized by increased insulin resistance, a well-known risk factor for diabetes and cardiovascular diseases. The aim of the present study was to evaluate the effect of abatacept on insulin sensitivity in RA patients with moderate to severe disease despite treatment with methotrexate. Fifteen RA patients were recruited for the present study. Patients were evaluated at time 0 and after 6 months of the treatment with i.v. abatacept at the dosage recommended for weight range. Evaluation included oral glucose tolerance test (OGTT) at both time points. Insulin sensitivity was estimated with insulin sensitivity index (ISI) by Matsuda, a measure of whole-body insulin sensitivity. ISI significantly increased after the treatment with abatacept from 3.7 ± 2.6 to 5.0 ± 3.2 (P = 0.003) with a mean difference of 1.23. Analysis of glucose and insulin values during OGTT revealed a reduction of both glucose (303.9 ± 73.4 mg/dL min versus 269.2 ± 69.5 mg/dL min, P = 0.009) and insulin (208.4 ± 119.7 mg/dL min versus 158.0 ± 95.3 mg/dL min, P = 0.01) area under the curves (AUCs). Accordingly also glycated hemoglobin significantly improved (5.5 ± 0.4% versus 5.3 ± 0.3%, P = 0.04). No significant differences were found for measures of β-cell function insulinogenic index (1.11 ± 1.19 versus 1.32 ± 0.82, P = 0.77) and oral disposition index (2.0 ± 5.4 versus 6.0 ± 6.0, P = 0.25). Treatment with abatacept seems to be able to improve whole-body insulin sensitivity in RA patients without affecting β-cell function.

Obesity-related immune responses and their impact on surgical outcomes

The obesity epidemic represents a critical disease burden with broad clinical consequences. At the same time, obesity has been linked to inferior surgical outcomes and considered a contraindication for some elective surgical procedures. A growing body of mechanistic evidence has accumulated linking obesity to changes of metabolism and immune responses. This concept provides an integrated inflammatory network based on the perception of obesity as a state of chronic low-grade inflammation. With a more detailed understanding of this dynamic network and mechanistic insights, novel treatment and management strategies may be developed with the goal to optimize surgical outcomes in obese patients.

Obesity and cancer: at the crossroads of cellular metabolism and proliferation

Obesity is associated with an increased risk of cancer. The mechanisms underlying this association include but are not limited to increased systemic inflammation, an anabolic hormonal milieu, and adipocyte-cancer crosstalk, aberrant stimuli that conspire to promote neoplastic transformation. Cellular proliferation is uncoupled from nutrient availability in malignant cells, promoting tumor progression. Elucidation of the mechanisms underlying the obesity-cancer connection will lead to the development of novel metabolism-based agents for cancer prevention and treatment.

Anti-inflammatory agents to treat or prevent type 2 diabetes, metabolic syndrome and cardiovascular disease

INTRODUCTION

There is a growing body of evidence to suggest that chronic silent inflammation is a key feature in abdominal obesity, metabolic syndrome, type 2 diabetes (T2DM) and cardiovascular disease (CVD). These observations suggest that pharmacological strategies, which reduce inflammation, may be therapeutically useful in treating obesity, type 2 diabetes and associated CVD.

AREA COVERED

The article covers novel strategies, using either small molecules or monoclonal antibodies. These strategies include: approaches targeting IKK-b-NF-kB (salicylates, salsalate), TNF-α (etanercept, infliximab, adalimumab), IL-1β (anakinra, canakinumab) and IL-6 (tocilizumab), AMP-activated protein kinase activators, sirtuin-1 activators, mammalian target of rapamycin inhibitors and C-C motif chemokine receptor 2 antagonists.

EXPERT OPINION

The available data supports the concept that targeting inflammation improves insulin sensitivity and β-cell function; it also ameliorates glucose control in insulin-resistant patients with inflammatory rheumatoid diseases as well in patients with metabolic syndrome or T2DM. Although promising, the observed metabolic effects remain rather modest in most clinical trials. The potential use of combined anti-inflammatory agents targeting both insulin resistance and insulin secretion appears appealing but remains unexplored. Large-scale prospective clinical trials are underway to investigate the safety and efficacy of different anti-inflammatory drugs. Further evidence is needed to support the concept that targeting inflammation pathways may represent a valuable option to tackle the cardiometabolic complications of obesity.

Elevated platelet expression of CD36 may contribute to increased risk of thrombo-embolism in active inflammatory bowel disease

CONTEXT

Inflammatory bowel disease (IBD) induces increased risk of thrombo-embolism. CD36 is involved in platelet activation, glucose metabolism and inflammation.

OBJECTIVE

The relationship between CD36 expression on platelets and monocytes, plasma sCD36, and CD36-positive platelet-derived microparticles (PDMPs) and inflammation in both active IBD and after one week of anti-tumour necrosis alpha antibody (anti-TNF) treatment was investigated.

MATERIAL AND METHODS

Patients with exacerbation of Crohn's disease (n = 8) or ulcerative colitis (n = 5) and 13 healthy controls were enrolled. Seven patients underwent anti-TNF treatment for one week. Platelet, monocyte, and PDMP-CD36 were measured by flow-cytometry.

RESULTS

Platelet CD36 expression was 34% higher in patients, and correlated with insulin resistance and fasting glucose. sCD36 was 37% lower and restored after anti-TNF treatment.

CONCLUSION

Elevated platelet CD36 expression may contribute to increased risk of thrombo-embolism in active IBD. This may not entirely be attributed to inflammation and secondary insulin resistance may play a role.

Spirulina improves non-alcoholic steatohepatitis, visceral fat macrophage aggregation, and serum leptin in a mouse model of metabolic syndrome

BACKGROUND

Nutritional approaches are sought to overcome the limits of pioglitazone in metabolic syndrome and non-alcoholic fatty liver disease. Spirulina, a filamentous unicellular alga, reduces serum lipids and blood pressure while exerting antioxidant effects.

AIM

To determine whether Spirulina may impact macrophages infiltrating the visceral fat in obesity characterizing our metabolic syndrome mouse model induced by the subcutaneous injection treatment of monosodium glutamate.

METHODS

Mice were randomized to receive standard food added with 5% Spirulina, 0.02% pioglitazone, or neither. We tested multiple biochemistry and histology (both liver and visceral fat) readouts at 24 weeks of age.

RESULTS

Data demonstrate that both the Spirulina and the pioglitazone groups had significantly lower serum cholesterol and triglyceride levels and liver non-esterified fatty acid compared to untreated mice. Spirulina and pioglitazone were associated with significantly lower leptin and higher levels, respectively, compared to the control group. At liver histology, non-alcoholic fatty liver disease activity score and lipid peroxide were significantly lower in mice treated with Spirulina.

CONCLUSIONS

Spirulina reduces dyslipidaemia in our metabolic syndrome model while ameliorating visceral adipose tissue macrophages. Human studies are needed to determine whether this safe supplement could prove beneficial in patients with metabolic syndrome.

Improvement in insulin resistance after short-term treatment with abatacept: case report and short review

Insulin resistance, a key feature of type 2 diabetes, is an independent risk factor for developing cardiovascular diseases (CVD), and represents the core of metabolic syndrome (MetS). Actually, an intriguing correlation between MetS and inflammation associated with rheumatoid arthritis (RA) is largely accepted but not yet completely clarified in detail. Recently, the therapeutic arsenal against RA has been enriched of abatacept, a fusion protein (CTLA4 immunoglobulin) designed to modulate the T cell co-stimulatory signal mediated through the CD28-CD80/86 pathway. Here, we report a case of dramatic improvement in insulin resistance, estimated with the surrogate measure HOMA-IR, after treatment with abatacept. Lastly, we shortly review the preclinical evidences supporting a possible role of T lymphocytes in rheumatoid arthritis-associated insulin resistance and how abatacept could improve glucose metabolism by suppressing adipose tissue infiltrating cells.

Autoimmunity in 2010

There is now growing evidence that autoimmunity is the common trait connecting multiple clinical phenotypes albeit differences in tissue specificity, pathogenetic mechanisms, and therapeutic approaches cannot be overlooked. Over the past years we witnessed a constant growth of the number of publications related to autoimmune diseases in peer-reviewed journals of the immunology area. Original data referred to factors from common injury pathways (i.e. T helper 17 cells, serum autoantibodies, or vitamin D) and specific diseases such as multiple sclerosis, systemic lupus erythematosus, and rheumatoid arthritis. As an example, the issue of a latitudinal gradient in the prevalence and incidence rates has been proposed for all autoimmune diseases and was recently coined as geoepidemiology to suggest new environmental triggers for tolerance breakdown. The present article is aimed at reviewing the articles that were published over the past year in the major autoimmunity and immunology journals.

The metabolic syndrome: the crossroads between rheumatoid arthritis and cardiovascular risk

Rheumatoid arthritis (RA) patients have an incidence of cardiovascular (CV) diseases at least two times higher than the general population. Atherosclerosis, the main determinant of CV morbidity and mortality, and carotid intima-media thickness, an early preclinical marker of atherosclerosis, also occur early on in RA. Traditional CV risk factors seem to have the same prevalence in RA and non-RA patients, and thus do not fully explain the increased CV burden, suggesting that RA inflammation and therapies play a role in increasing CV risk in these patients. The metabolic syndrome and fat tissue are likely to be the major players in this complex network. The metabolic syndrome (MetS) represents a cluster of cardiovascular risk factors that have in common insulin resistance and increased visceral adiposity. This entity has received great attention in the last few years due to its contribution to the burden of cardiovascular morbidity and mortality. Moreover, recently the adipose tissue has emerged as a dynamic organ that releases several inflammatory and immune mediators (adipokines). The association of MetS and atherosclerosis is thought to be partly mediated by altered secretion of adipokines by the adipose tissue and, on the other hand, there are evidence that adipokines may play some role in inflammatory arthritides. Obesity is now regarded as a systemic, low-grade inflammatory state, and inflammation as a link between obesity, metabolic syndrome, and cardiovascular diseases. To obtain a full control of the CV risk, data suggest that it is therefore mandatory a "tight control" of both RA and MetS inflammations.

Association between systemic inflammation and incident diabetes in HIV-infected patients after initiation of antiretroviral therapy

OBJECTIVE

To determine whether systemic inflammation after initiation of HIV-antiretroviral therapy (ART) is associated with the development of diabetes.

RESEARCH DESIGN AND METHODS

We conducted a nested case-control study, comparing 55 previously ART-naive individuals who developed diabetes 48 weeks after ART initiation (case subjects) with 55 individuals who did not develop diabetes during a comparable follow-up (control subjects), matched on baseline BMI and race/ethnicity. Stored plasma samples at treatment initiation (week 0) and 1 year later (week 48) were assayed for levels of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and the soluble receptors of tumor necrosis factor-α (sTNFR1 and sTNFR2).

RESULTS

Case subjects were older than control subjects (median age 41 vs. 37 years, P = 0.001), but the groups were otherwise comparable. Median levels for all markers, except hs-CRP, decreased from week 0 to week 48. Subjects with higher levels of hs-CRP, sTNFR1, and sTNFR2 at 48 weeks had an increased odds of subsequent diabetes, after adjustment for baseline marker level, age, BMI at week 48, CD4 count at week 48 (< vs. >200 cells/mm(3)), and indinavir use (all P(trend) ≤ 0.05). After further adjustment for week 48 glucose, effects were attenuated and only sTNFR1 remained significant (odds ratio, highest quartile vs. lowest 23.2 [95% CI 1.28-423], P = 0.03).

CONCLUSIONS

Inflammatory markers 48 weeks after ART initiation were associated with increased risk of diabetes. These findings suggest that systemic inflammation may contribute to diabetes pathogenesis among HIV-infected patients.

Biologics - beyond the joints

Biologics including tumor necrosis factor α (TNF-α), interleukin-6 receptor (IL-6R), T and B cell inhibitors are very effective therapeutic agents for the treatment of arthritides. These compounds effectively improve articular symptoms and inhibit joint damage. In this respect, there are no major differences in the efficacy of the available biologics. However, many arthritis patients also exert extra-articular features, systemic manifestations of the disease. These associated conditions include uveitis, inflammatory bowel disease, psoriasis, secondary bone loss and cardiovascular disease. There have been data suggesting that there may be differences in the effects of various TNF inhibitors, rituximab and tocilizumab on the systemic manifestations described above. At present, we do not always have sufficient evidence to confirm these differences, therefore, more information should be obtained from large trials and long-term observational studies.