Increased plasma interleukin-1 receptor antagonist levels in men with visceral obesity

Altered proteome profiles related to visceral adiposity may mediate the favorable effect of green Mediterranean diet: the DIRECT-PLUS trial

OBJECTIVE

The objective of this study was to explore the effects of a green Mediterranean (green-MED) diet, which is high in dietary polyphenols and green plant-based protein and low in red/processed meat, on cardiovascular disease and inflammation-related circulating proteins and their associations with cardiometabolic risk parameters.

METHODS

In the 18-month weight loss trial Dietary Intervention Randomized Controlled Trial Polyphenols Unprocessed Study (DIRECT-PLUS), 294 participants with abdominal obesity were randomized to basic healthy dietary guidelines, Mediterranean (MED), or green-MED diets. Both isocaloric MED diet groups consumed walnuts (28 g/day), and the green-MED diet group also consumed green tea (3-4 cups/day) and green shakes (Mankai plant shake, 500 mL/day) and avoided red/processed meat. Proteome panels were measured at three time points using Olink CVDII.

RESULTS

At baseline, a dominant protein cluster was significantly related to higher phenotypic cardiometabolic risk parameters, with the strongest associations attributed to magnetic resonance imaging-assessed visceral adiposity (false discovery rate of 5%). Overall, after 6 months of intervention, both the MED and green-MED diets induced improvements in cardiovascular disease and proinflammatory risk proteins (p < 0.05, vs. healthy dietary guidelines), with the green-MED diet leading to more pronounced beneficial changes, largely driven by dominant proinflammatory proteins (IL-1 receptor antagonist protein, IL-16, IL-18, thrombospondin-2, leptin, prostasin, galectin-9, and fibroblast growth factor 21; adjusted for age, sex, and weight loss; p < 0.05). After 18 months, proteomics cluster changes presented the strongest correlations with visceral adiposity reduction.

CONCLUSIONS

Proteomics clusters may enhance our understanding of the favorable effect of a green-MED diet that is enriched with polyphenols and low in red/processed meat on visceral adiposity and cardiometabolic risk.

Serum Levels of IL-1 RA Increase with Obesity and Type 2 Diabetes in Relation to Adipose Tissue Dysfunction and are Reduced After Bariatric Surgery in Parallel to Adiposity

Background

Excess adiposity leads to a dysfunctional adipose tissue that contributes to the development of obesity-associated comorbidities such as type 2 diabetes (T2D). Interleukin-1 receptor antagonist (IL-1RA) is a naturally occurring antagonist of the IL-1 receptor with anti-inflammatory properties. The aim of the present study was to compare the circulating concentrations of IL-1RA and its mRNA expression in visceral adipose tissue (VAT) in subjects with normal weight (NW), obesity with normoglycemia (OB-NG), or obesity with impaired glucose tolerance or T2D (OB-IGT&T2D) and to analyze the effect of changes in body fat percentage (BF%) on IL-1RA levels.

Methods

Serum concentrations of IL-1RA were measured in 156 volunteers. Expression of IL1RN mRNA in VAT obtained from 36 individuals was determined. In addition, the concentrations of IL-1RA were measured before and after weight gain as well as weight loss following a dietetic program or Roux-en-Y gastric bypass (RYGB).

Results

Serum levels of IL-1RA were significantly increased in individuals with obesity, being further increased in the OB-IGT&T2D group (NW 440 ± 316, OB-NG 899 ± 562, OB-IGT&T2D 1265 ± 739 pg/mL; P<0.001) and associated with markers of inflammation and fatty liver. IL1RN mRNA expression in VAT was significantly increased in the OB-IGT&T2D group and correlated in the global cohort with the mRNA expression of SPP1, CCL2, CD68, and MMP9. Levels of IL-1RA were not modified after modest changes in BF%, but RYGB-induced weight loss significantly decreased IL-1RA concentrations from 1233 ± 1009 to 660 ± 538 pg/mL (P<0.001).

Conclusion

Serum IL-1RA concentrations are increased in patients with obesity being further elevated in obesity-associated IGT and T2D in association with markers of adipose tissue dysfunction. The mRNA expression of IL1RN is markedly increased in VAT of subjects with obesity and T2D in relation with genes involved in macrophage recruitment, inflammation and matrix remodeling. Serum IL-1RA concentrations are reduced when a notable amount of BF% is loss. Measurement of IL-1RA is an excellent biomarker of adipose tissue dysfunction in obesity-associated metabolic alterations.

Serum IL-1 Receptor Antagonist Concentrations Associate With Unfavorable Metabolic Features in 12-Year-Old Children

Context

Elevated IL-1 receptor antagonist (IL-1Ra) concentrations are associated with obesity, insulin resistance, and cardiovascular disease (CVD) risk in adults.

Objective

To determine if serum IL-1Ra and high-sensitivity C-reactive protein (hs-CRP) levels are associated with markers of reduced insulin sensitivity (IS) and serum lipids in 12-year-old children.

Design and Participants

Of 191 children (n = 109 girls), 78 were categorized as having had birth weight and length appropriate for gestational age (AGA), 69 were small for gestational age, and 44 were AGA and from preeclamptic pregnancies. Serum markers of low-grade inflammation, IS, and lipids were measured. Quantitative Insulin Sensitivity Check Index (QUICKI) was calculated.

Results

Mean serum IL-1Ra levels did not differ between the sexes or among the gestational categories. Children in the highest IL-1Ra tertile had lower QUICKI, IGF-binding protein-1, SHBG, and high-density lipoprotein cholesterol values; and higher body mass index (BMI), waist circumference to height ratio (WHtR), and serum insulin, hs-CRP, leptin, and triglyceride concentrations than those in the lowest IL-1Ra tertile. Logistic regression analysis showed higher serum hs-CRP and leptin levels, and WHtR were associated with high serum IL-1Ra levels. IL-1Ra concentration could be used to discriminate the children with lowest IS (area under the curve, 0.68; P < 0.001); hs-CRP level could not.

Conclusion

Children with the highest IL-1Ra levels had lower IS, higher hs-CRP levels and BMI, and a less favorable lipid profile than those with the lowest IL-1Ra levels, suggesting that high IL-1Ra concentrations may be associated with increased CVD risk in 12-year-old children.

Plasma IL-1Ra: linking hyperapoB to risk factors for type 2 diabetes independent of obesity in humans

Background/Objective:

Plasma apoB predicts the incidence of type 2 diabetes (T2D); however, the link between apoB-linpoproteins and risks for T2D remain unclear. Insulin resistance (IR) and compensatory hyperinsulinemia characterize prediabetes, and the involvement of an activated interleukin-1 (IL-1) family, mainly IL-1β and its receptor antagonist (IL-Ra), is well documented. ApoB-lipoproteins were reported to promote IL-1β secretion in immune cells; however, in vivo evidence is lacking. We hypothesized that obese subjects with hyperapoB have an activated IL-1 system that explains hyperinsulinemia and IR in these subjects.

Subjects/Methods:

We examined 81 well-characterized normoglycemic men and postmenopausal women (⩾27 kg m⁻², 45–74 years, non-smokers, sedentary, free of chronic disease). Insulin secretion and sensitivity were measured by the gold-standard Botnia clamp, which is a combination of a 1-h intravenous glucose tolerance test (IVGTT) followed by 3-h hyperinsulinemic euglycemic clamp.

Results:

Plasma IL-1β was near detection limit (0.071–0.216 pg ml⁻¹), while IL-1Ra accumulated at 1000-folds higher (77–1068 pg ml⁻¹). Plasma apoB (0.34–1.80 g l⁻¹) associated significantly with hypersinsulinemia (total_IVGTT: C-peptide r=0.27, insulin r=0.22), IR (M/I=−0.29) and plasma IL-1Ra (r=0.26) but not with IL-1β. Plasma IL-1Ra associated with plasma IL-1β (r=0.40), and more strongly with hyperinsulinemia and IR than apoB, while the association of plasma IL-1β was limited to second phase and total insulin secretion (r=0.23). Adjusting the association of plasma apoB to hyperinsulinemia and IR for IL-1Ra eliminated these associations. Furthermore, despite equivalent body composition, subjects with hyperapoB (⩾80th percentile, 1.14 g l⁻¹) had higher C-peptide secretion and lower insulin sensitivity than those with low plasma apoB (⩽20th percentile, 0.78 g l⁻¹). Adjustment for plasma IL-1 Ra eliminated all group differences.

Conclusion:

Plasma apoB is associated with hyperinsulinemia and IR in normoglycemic obese subjects, which is eliminated upon adjustment for plasma IL-1Ra. This may implicate the IL-1 family in elevated risks for T2D in obese subjects with hyperapoB.

Urine chemokines indicate pathogenic association of obesity with BPH/LUTS

OBJECTIVES

High prevalence of lower urinary tract symptoms (LUTS) consistent with benign prostate hyperplasia (BPH) is associated with obesity and prostatic inflammation. Here, we investigated whether chemokines associated with obesity and prostatic inflammation can be measured in normally voided urine of BPH/LUTS patients to demonstrate the mechanistic association between obesity and BPH/LUTS.

METHODS

Frozen urine specimens of BPH/LUTS patients enrolled in the Nashville Men's Health Study were sent for blinded analysis to University of Pittsburgh. Thirty patients were blocked by their AUA-SI (>7 or ≤7) and prostatic enlargement (<40, 40-60, >60 cc). Clinical parameters including age, prostate size, and medications were derived from chart review. CXC chemokines (CXCL-1, CXCL-8, and CXCL-10), CC chemokines (CCL2 and CCL3), and sIL-1ra were measured in thawed urine using Luminex™ xMAP(®) technology and ELISA for NGF.

RESULTS

Urinary CCL2 levels were several fold higher compared with the other six proteins, of which CCL3 was detectable in less than one-fourth of patients. Urine levels of sIL-1ra and CXCL-8 were significantly associated with increasing BMI and waist circumference in BPH patients. CXCL-8 showed a marginal association with overall AUA-SI scores, as well as obstructive (p = 0.08) symptom subscores. Prostate volume was inversely and marginally associated with urinary CXCL-10 (p = 0.09).

CONCLUSIONS

Urine levels of CXCL-8, CXCL-10, and sIL-1ra were associated with varying degrees with LUTS severity, prostate size, and obesity, respectively. These findings in urine are consistent with past studies of chemokine levels from expressed prostatic secretions and demonstrate the potential of noninvasively measured chemokine in urine to objectively classify BPH/LUTS patients.

Adipose tissue distribution in relation to insulin sensitivity and inflammation in Pakistani and Norwegian subjects with type 2 diabetes

Immigrants from South Asia to Western countries have a high prevalence of type 2 diabetes mellitus (T2DM) associated with obesity. We investigated the relationship between diabetes and adipose tissue distribution in a group of younger T2DM subjects from Norway and Pakistan. Eighteen immigrant Pakistani and 21 Norwegian T2DM subjects (age 29-45, 49% men) were included. They underwent anthropometrical measurements including bioelectrical impedance analysis, CT scans measuring fatty infiltration in liver and adipose and muscle tissue compartments in mid-abdomen and thigh, a euglycemic clamp, and blood samples for serum insulin and plasma glucose, adipokines and inflammation markers. Adipose tissue distribution was similar in Norwegians and Pakistanis. Pakistanis, but not Norwegians, showed a negative correlation between insulin sensitivity and visceral adipose tissue (VAT, rs = - 0.704, p = 0.003). Subcutaneous adipose tissue (SAT) correlated to leptin in both Pakistanis and Norwegians (rs = 0.88, p < 0.001 and 0.67, p = 0.001). SAT also correlated to C-reactive protein (CRP) in the Pakistanis only (rs = 0.55, p = 0.03), and superficial SAT to Interleukin-1 receptor antagonist (IL-1RA) in Norwegians only (rs = 0.47, p = 0.04). In conclusion, despite similar adipose tissue distribution in the two groups Pakistanis were more insulin resistant, with a negative correlation of VAT to insulin sensitivity, not present in Norwegians. The correlation of adipose tissue to Leptin, CRP and IL-1RA showed ethnic differences.

Environmental perturbations: Obesity

Obesity currently affects about one-third of the U.S. population, while another one-third is overweight. The importance of obesity for certain conditions such as heart disease and type 2 diabetes is well appreciated. The effects of obesity on the respiratory system have received less attention and are the subject of this article. Obesity alters the static mechanical properties of the respiratory system leading to a reduction in the functional residual capacity (FRC) and the expiratory reserve volume (ERV). There is substantial variability in the effects of obesity on FRC and ERV, at least some of which is related to the location rather than the total mass of adipose tissue. Obesity also results in airflow obstruction, which is only partially attributable to breathing at low lung volume, and can also promote airway hyperresponsiveness and asthma. Hypoxemia is common is obesity and correlates well with FRC, as well as with measures of abdominal obesity. However, obese subjects are usually eucapnic, indicating that hypoventilation is not a common cause of their hypoxemia. Instead, hypoxemia results from ventilation-perfusion mismatch caused by closure of dependent airways at FRC. Many obese subjects complain of dyspnea either at rest or during exertion, and the dyspnea score also correlates with reductions in FRC and ERV. Weight reduction should be encouraged in any symptomatic obese individual, since virtually all of the respiratory complications of obesity improve with even moderate weight loss.

The systemic immune network in recent onset type 1 diabetes: central role of interleukin-1 receptor antagonist (DIATOR Trial)

Background

The hypothesis was tested that the systemic immune milieu in recent-onset type 1 diabetes is associated with residual beta cell function and other metabolic patient characteristics.

Methods and Findings

All patients (n = 89, 40% female) of the Diabetes and Atorvastatin (DIATOR) Trial were analyzed at recruitment, i.e. prior to receiving the study medication. Inclusion criteria were insulin dependent diabetes for 2 weeks to 3 months, age range 18–39 years, and islet cell autoantibodies. Blood samples were analyzed for 14 immune mediators by standard methods. Concentrations of all mediators correlated with at least one other mediator (p<0.05, Spearman correlation) giving rise to a network. Interleukin 1 receptor antagonist (IL1-RA) held a central position and was associated with both pro- and anti-inflammatory mediators. Further central elements were the pro-inflammatory mediators CRP and IL-6, the soluble adhesion molecules sICAM-1 and E-selectin, and MCP-4 which held a central position in the chemokine network. The two Th1-associated mediators IFNγ and IP-10 remained outside the network but correlated with each other. All correlations were positive (r = 0.25–0.72), i.e., high levels of pro-inflammatory mediators were accompanied by increased levels of anti-inflammatory mediators. IL-1RA was the only mediator associated with fasting and liquid mixed meal stimulated C-peptide concentrations (r = 0.31 and 0.24, p = 0.003 and 0.025, after adjustment for age, sex, BMI). There were associations between the immune mediator network and BMI (IL-1RA, CRP, IL-6, MCP-4, MIP-1ß) but few or no associations with HbA1c, insulin dose, lipid parameters, age or sex.

Conclusions

In patients with recent onset type 1 diabetes, systemic acute phase proteins, cytokines, chemokines and soluble adhesion molecules form a network. Among the few central elements IL-1RA has a dominant role. IL-1RA is associated with all other groups of mediators and is the only mediator which correlates (positively) with residual beta cell function.

Trial registration

ClinicalTrials.gov registration number: NCT00974740

Impact of visceral obesity on cardiac parasympathetic activity in type 2 diabetics after coronary artery bypass graft surgery

OBJECTIVE

The association between adiposity and heart rate variability (HRV) in patients with type 2 diabetes (T2D) after coronary artery bypass graft surgery (CABG) is not well documented. We evaluated the associations between indices of adiposity and HRV in patients with T2D with CABG and quantified the relationships of the volume of visceral (VVAT) and subcutaneous adipose tissue (VSAT) to HRV.

DESIGN AND METHODS

One hundred and thirty-five men with T2D who underwent CABG participated in this study. HRV, BMI, waist circumference (WC), VVAT, and VSAT were measured. Correlations between indices of HRV and adiposity were evaluated and predictors of HRV modulation were identified. Patients were then divided into quartiles of VVAT and VSAT to further evaluate the influence of adiposity on HRV.

RESULTS

Subjects were 65 ± 7 years old (mean ± SD) with a BMI of 30 ± 4 kg/m(2) and a WC of 105 ± 10 cm. BMI (r = -0.19) and WC (r = -0.25) were inversely correlated with low frequencies. VVAT correlated negatively with SD normal-to normal (SDNN) (r = -0.22, P < 0.01), indices of cardiac parasympathetic activity [rMSSD (r = -0.27), NN50 (r = -0.22), pNN50 (r = -0.26; all P < 0.05], and with low (r = -0.37) and high frequencies (r = -0.20; all P < 0.01). Patients with the lowest VVAT had the highest cardiac parasympathetic activity (P < 0.05). VVAT remained the best predictor of cardiac parasympathetic activity after adjustments for confounding parameters (P < 0.01).

CONCLUSION

An increase in visceral adiposity, not BMI, seems to be associated with lower HRV in patients with T2D who had a CABG procedure.

Adipose tissue-related proteins locally associated with resolution of inflammation in obese mice

OBJECTIVE

Resolution of low-grade inflammation of white adipose tissue (WAT) is one of the keys for amelioration of obesity-associated metabolic dysfunctions. We focused on the identification of adipokines, which could be involved at the early stages of resolution of WAT inflammation.

METHODS AND PROCEDURE

Male C57BL/6J mice with obesity induced in response to a 22-week feeding corn oil-based high-fat (cHF) diet were divided into four groups and were fed with, for 2 weeks, control cHF diet or cHF-based diets supplemented with: (i) concentrate of n-3 long-chain polyunsaturated fatty acids, mainly eicosapentaenoic and docosahexaenoic acids (cHF+F); (ii) thiazolidinedione drug rosiglitazone (cHF+TZD); and (iii) both compounds (cHF+F+TZD).

RESULTS

The short-term combined intervention exerted additive effect in the amelioration of WAT inflammation in obese mice, namely in the epididymal fat, even in the absence of any changes in either adipocyte volume or fat mass. The combined intervention elicited hypolipidaemic effect and induced adiponectin, whereas the responses to single interventions (cHF+F, cHF+TZD) were less pronounced. In addition, analysis in WAT lysates using protein arrays revealed that the levels of a small set of adipose tissue-related proteins, namely macrophage inflammatory protein 1γ, endoglin, vascular cell adhesion molecule 1 and interleukin 1 receptor antagonist, changed in response to the anti-inflammatory interventions and were strongly reduced in the cHF+F+TZD mice. These results were verified using both the analysis of gene expression and enzyme-linked immunosorbent analysis in WAT lysates. In contrast with adiponectin, which showed changing plasma levels in response to dietary interventions, the levels of the above proteins were affected only in WAT.

CONCLUSIONS

We identified several adipose tissue-related proteins, which are locally involved in resolution of low-grade inflammation and remodelling of WAT.

Genome-wide associated loci influencing interleukin (IL)-10, IL-1Ra, and IL-6 levels in African Americans

Interleukins (ILs) are key mediators of the immune response and inflammatory process. Plasma levels of IL-10, IL-1Ra, and IL-6 are associated with metabolic conditions, show large inter-individual variations, and are under strong genetic control. Therefore, elucidation of the genetic variants that influence levels of these ILs provides useful insights into mechanisms of immune response and pathogenesis of diseases. We conducted a genome-wide association study (GWAS) of IL-10, IL-1Ra, and IL-6 levels in 707 non-diabetic African Americans using 5,396,780 imputed and directly genotyped single nucleotide polymorphisms (SNPs) with adjustment for gender, age, and body mass index. IL-10 levels showed genome-wide significant associations (p  < 5 × 10(-8)) with eight SNPs, the most significant of which was rs5743185 in the PMS1 gene (p = 2.30 × 10(-10)). We tested replication of SNPs that showed genome-wide significance in 425 non-diabetic individuals from West Africa, and successfully replicated rs17365948 in the YWHAZ gene (p = 0.02). IL-1Ra levels showed suggestive associations with two SNPs in the ASB3 gene (p = 2.55 × 10(-7)), ten SNPs in the IL-1 gene family (IL1F5, IL1F8, IL1F10, and IL1Ra, p = 1.04 × 10(-6) to 1.75 × 10(-6)), and 23 SNPs near the IL1A gene (p = 1.22 × 10(-6) to 1.63 × 10(-6)). We also successfully replicated rs4251961 (p = 0.009); this SNP was reported to be associated with IL-1Ra levels in a candidate gene study of Europeans. IL-6 levels showed genome-wide significant association with one SNP (RP11-314E23.1; chr6:133397598; p = 8.63 × 10(-9)). To our knowledge, this is the first GWAS on IL-10, IL-1Ra, and IL-6 levels. Follow-up of these findings may provide valuable insight into the pathobiology of IL actions and dysregulations in inflammation and human diseases.

Improved preservation of residual beta cell function by atorvastatin in patients with recent onset type 1 diabetes and high CRP levels (DIATOR trial)

Background

A recent randomized placebo-controlled trial of the effect of atorvastatin treatment on the progression of newly diagnosed type 1 diabetes suggested a slower decline of residual beta cell function with statin treatment. Aim of this secondary analysis was to identify patient subgroups which differ in the decline of beta cell function during treatment with atorvastatin.

Methodology/Principal Findings

The randomized placebo-controlled Diabetes and Atorvastatin (DIATOR) Trial included 89 patients with newly diagnosed type 1 diabetes and detectable islet autoantibodies (mean age 30 years, 40% females), in 12 centers in Germany. Patients received placebo or 80 mg/d atorvastatin for 18 months. As primary outcome stimulated serum C-peptide levels were determined 90 min after a standardized liquid mixed meal. For this secondary analysis patients were stratified by single baseline characteristics which were considered to possibly be modified by atorvastatin treatment. Subgroups defined by age, sex or by baseline metabolic parameters like body mass index (BMI), total serum cholesterol or fasting C-peptide did not differ in C-peptide outcome after atorvastatin treatment. However, the subgroup defined by high (above median) baseline C-reactive protein (CRP) concentrations exhibited higher stimulated C-peptide secretion after statin treatment (p = 0.044). Individual baseline CRP levels correlated with C-peptide outcome in the statin group (r² = 0.3079, p<0.004). The subgroup with baseline CRP concentrations above median differed from the corresponding subgroup with lower CRP levels by higher median values of BMI, IL-6, IL-1RA, sICAM-1 and E-selectin.

Conclusions/Significance

Atorvastatin treatment may be effective in slowing the decline of beta cell function in a patient subgroup defined by above median levels of CRP and other inflammation associated immune mediators.

Trial Registration

ClinicalTrials.gov NCT00974740

Inflammation in psychotic disorders: a population-based study

We investigated inflammatory markers in psychotic disorders and their association with metabolic comorbidity, antipsychotic medication, smoking, alcohol use, physical condition, and mood. From the population-based Finnish Health 2000 study, we identified all persons with schizophrenia (n=45), other nonaffective psychosis (ONAP) (n=57), affective psychosis (n=37) and chose controls matched by age, sex, and region of residence. We found that persons with schizophrenia had significantly higher sIL-2Rα, IL-1RA and C-reactive protein (CRP), persons with ONAP significantly higher IL-1RA and CRP and persons with affective psychosis almost significantly higher TNF-α compared to their matched controls. Current antipsychotic use was associated with elevated IL-1RA and CRP. After taking metabolic and lifestyle-related variables that associated with inflammatory markers into account, only antipsychotic medication remained associated with elevated IL-1RA and TNF-α which are markers related to the activation of innate immune system. CRP was influenced by both antipsychotic medication and nonaffective psychosis. sIL-2Rα, a marker of T-cell activation, was associated with depressive symptoms, schizophrenia, and affective psychosis. We conclude that in persons with psychotic disorders, activation of mononuclear phagocyte system was mostly related to metabolic comorbidity and antipsychotic medication use, whereas T-cell activation had a more direct relationship with both psychotic disorders and depressive symptoms.

Interleukin 1 receptor antagonist is associated with changes in body composition during physiological GH substitution in patients with adult-onset growth hormone deficiency

OBJECTIVE

We examined the effect of GH substitution on adipose tissue-derived hormones and cytokines and sought to identify predictors for changes in body composition during therapy. Long-standing adult-onset GH deficiency (AO-GHD) is associated with increased body fat mass (FM) which, through production of hormones and inflammatory cytokines from adipose tissue, may contribute to different manifestations of the metabolic syndrome.

DESIGN, PATIENTS AND MEASUREMENTS

Fifty-five patients with AO-GHD (24 women, 31 men, mean age 49 years) were enrolled in a placebo-controlled, double-blind crossover study. GH therapy was individually dosed to obtain an IGF-I concentration within the normal range for age and sex. GH and placebo were administered for 9 months each, separated by a 4-month washout period. Adipose tissue-derived cytokines were measured by enzyme immunoassay.

RESULTS

GH treatment was associated with a significant decrease in IL-1 receptor antagonist (IL-1Ra) compared to placebo, which correlated with declining body FM (truncal and total) after GH substitution. The change in IL-1Ra was the strongest predictor of the variation in BFM in regression models. No changes were observed for leptin, adiponectin, soluble TNF receptor 1 or interleukin (IL)-8.

CONCLUSION

The data indicate a possible unrecognized association between IL-1Ra and changes in body composition during GH substitution and suggest further research on the interaction between the GH-IGF axis and the IL-1 system.

Eating ourselves to death (and despair): the contribution of adiposity and inflammation to depression

Obesity and related metabolic conditions are of epidemic proportions in most of the world, affecting both adults and children. The accumulation of lipids in the body in the form of white adipose tissue in the abdomen is now known to activate innate immune mechanisms. Lipid accumulation causes adipocytes to directly secrete the cytokines interleukin (IL) 6 and tumor necrosis factor alpha (TNFalpha), but also monocyte chemoattractant protein 1 (MCP-1), which results in the accumulation of leukocytes in fat tissue. This sets up a chronic inflammatory state which is known to mediate the association between obesity and conditions such as cardiovascular disease, type 2 diabetes, and cancer. There is also a substantial literature linking inflammation with risk for depression. This includes the observations that: (1) people with inflammatory diseases such as multiple sclerosis, cardiovascular disease, and psoriasis have elevated rates of depression; (2) many people administered inflammatory cytokines such as interferon alpha develop depression that is indistinguishable from depression in non-medically ill populations; (3) a significant proportion of depressed persons show upregulation of inflammatory factors such as IL-6, C-reactive protein, and TNFalpha; (4) inflammatory cytokines can interact with virtually every pathophysiologic domain relevant to depression, including neurotransmitter metabolism, neuroendocrine function, and synaptic plasticity. While many factors may contribute to the association between inflammatory mediators and depression, we hypothesize that increased adiposity may be one causal pathway. Mediational analysis suggests a bi-directional association between adiposity and depression, with inflammation possibly playing an intermediary role.

Accelerated increase in serum interleukin-1 receptor antagonist starts 6 years before diagnosis of type 2 diabetes: Whitehall II prospective cohort study

OBJECTIVE

Although interleukin-1 receptor antagonist (IL-1Ra) treatment is associated with improved beta-cell function and glycemic control in patients with type 2 diabetes, its role in the development of type 2 diabetes remains unclear. We used repeated measurements to characterize IL-1Ra trajectories in individuals who developed type 2 diabetes.

RESEARCH DESIGN AND METHODS

This case-cohort study, nested within the Whitehall II cohort, was based on 335 incident type 2 diabetes cases and 2,475 noncases. We measured serum IL-1Ra levels at up to three time points per individual and estimated retrospective trajectories of IL-1Ra before diabetes diagnosis (case subjects) or end of follow-up (control subjects) using multilevel analysis. Models were adjusted for age, sex, and ethnicity.

RESULTS

IL-1Ra levels were already higher in the case than control subjects 13 years before diabetes diagnosis/end of follow-up (mean [95% CI] 302 [290-314] vs. 244 [238-249] pg/ml). In control subjects, IL-1Ra levels showed a modest linear increase throughout the study period. In case subjects, IL-1Ra trajectories were parallel to those in control subjects until 6 years (95% CI 7.5-4.5) before diagnosis and then rose steeply to 399 (379-420) pg/ml at the time of diagnosis (P < 0.0001 for slope difference). Adjustment for BMI and waist circumference as time-varying covariates had little impact on these trajectories.

CONCLUSIONS

We show elevated IL-1Ra levels for 13 years and an accelerated increase during the last 6 years before type 2 diabetes diagnosis, indicating the presence of an anti-inflammatory response that may act to counterbalance the metabolic and immunologic disturbances that precede type 2 diabetes.