Increased Levels of Interleukin-36 in Obesity and Type 2 Diabetes Fuel Adipose Tissue Inflammation by Inducing Its Own Expression and Release by Adipocytes and Macrophages

Serum IL-36β levels are associated with Insulin sensitivity in paediatric patients with obesity

Although the orchestrating role of Interleukin-36 cytokines in regulating inflammation at barrier tissue sites, is well established, whether they play a significant role in the settings of metabolic health and disease, has yet to be fully established. Several recent studies have demonstrated that IL-36 cytokine expression is elevated among adult patients with obesity, and can play roles in regulating both insulin sensitivity and driving inflammation. In this report, we have extended these analyses to paediatric patients and identified an association between elevated serum levels of expression of the specific Interleukin-36 subfamily member, IL-36β, among children with obesity displaying insulin sensitivity, compared to children with obesity who are insulin resistant. While these data further indicate a possible protective role for IL-36 in metabolic health, they also differ with previous findings from an adult patient cohort, where elevated levels of the related cytokine, IL-36γ, were found to occur in association with improved metabolic health. While highlighting important differences between paediatric and adult patient cohorts in the context of metabolic disease associated with obesity, these data underscore the need for a deeper mechanistic analysis of the role of IL-36 cytokines in disease.

Impact of intestinal microenvironments in obesity and bariatric surgery on shaping macrophages

Obesity is associated with alterations in tissue composition, systemic cellular metabolism, and low-grade chronic inflammation. Macrophages are heterogenous innate immune cells ubiquitously localized throughout the body and are key components of tissue homeostasis, inflammation, wound healing, and various disease states. Macrophages are highly plastic and can switch their phenotypic polarization and change function in response to their local environments. Here, we discuss how obesity alters the intestinal microenvironment and potential key factors that can influence intestinal macrophages as well as macrophages in other organs, including adipose tissue and hematopoietic organs. As bariatric surgery can induce metabolic adaptation systemically, we discuss the potential mechanisms through which bariatric surgery reshapes macrophages in obesity.

Adipose tissue specific CCL18 associates with cardiometabolic diseases in non-obese individuals implicating CD4+ T cells

AIM

Obesity is linked to cardiometabolic diseases, however non-obese individuals are also at risk for type 2 diabetes (T2D) and cardiovascular disease (CVD). White adipose tissue (WAT) is known to play a role in both T2D and CVD, but the contribution of WAT inflammatory status especially in non-obese patients with cardiometabolic diseases is less understood. Therefore, we aimed to find associations between WAT inflammatory status and cardiometabolic diseases in non-obese individuals.

METHODS

In a population-based cohort containing non-obese healthy (n = 17), T2D (n = 16), CVD (n = 18), T2D + CVD (n = 19) individuals, seventeen different cytokines were measured in WAT and in circulation. In addition, 13-color flow cytometry profiling was employed to phenotype the immune cells. Human T cell line (Jurkat T cells) was stimulated by rCCL18, and conditioned media (CM) was added to the in vitro cultures of human adipocytes. Lipolysis was measured by glycerol release. Blocking antibodies against IFN-γ and TGF-β were used in vitro to prove a role for these cytokines in CCL18-T-cell-adipocyte lipolysis regulation axis.

RESULTS

In CVD, T2D and CVD + T2D groups, CCL18 and CD4+ T cells were upregulated significantly compared to healthy controls. WAT CCL18 secretion correlated with the amounts of WAT CD4+ T cells, which also highly expressed CCL18 receptors suggesting that WAT CD4+ T cells are responders to this chemokine. While direct addition of rCCL18 to mature adipocytes did not alter the adipocyte lipolysis, CM from CCL18-treated T cells increased glycerol release in in vitro cultures of adipocytes. IFN-γ and TGF-β secretion was significantly induced in CM obtained from T cells treated with CCL18. Blocking these cytokines in CM, prevented CM-induced upregulation of adipocyte lipolysis.

CONCLUSION

We suggest that in T2D and CVD, increased production of CCL18 recruits and activates CD4+ T cells to secrete IFN-γ and TGF-β. This, in turn, promotes adipocyte lipolysis - a possible risk factor for cardiometabolic diseases.

Obesity and the risk of cardiometabolic diseases

The prevalence of obesity has reached pandemic proportions, and now approximately 25% of adults in Westernized countries have obesity. Recognized as a major health concern, obesity is associated with multiple comorbidities, particularly cardiometabolic disorders. In this Review, we present obesity as an evolutionarily novel condition, summarize the epidemiological evidence on its detrimental cardiometabolic consequences and discuss the major mechanisms involved in the association between obesity and the risk of cardiometabolic diseases. We also examine the role of potential moderators of this association, with evidence for and against the so-called 'metabolically healthy obesity phenotype', the 'fatness but fitness' paradox or the 'obesity paradox'. Although maintenance of optimal cardiometabolic status should be a primary goal in individuals with obesity, losing body weight and, particularly, excess visceral adiposity seems to be necessary to minimize the risk of cardiometabolic diseases.

Change in Adipokines and Gastrointestinal Hormones After Bariatric Surgery: a Meta-analysis

PURPOSE

The study aimed to perform a meta-analysis about the change in adipokines and gastrointestinal hormones after bariatric surgery in patients with obesity.

MATERIALS AND METHODS

We searched the Cochrane Central Register of Controlled Trials, EMBASE, and PubMed for related articles and used Review Manager 5.4 for data aggregation. Sensitivity and subgroup analysis were also conducted when feasible.

RESULTS

As a result, 95 articles involving 6232 patients were included in the meta-analysis. After bariatric surgery, the levels of leptin, ghrelin, C-reactive protein (CRP), interleukin-6 (IL-6), high-sensitivity C-reactive protein (Hs-CRP), tumor necrosis, factor-α (TNF-α), and interleukin-1β (IL-1β) reduced, while adiponectin, glucagon-like peptide-1 (GLP-1), and peptide YY (PYY) levels increased significantly. Subgroup analysis indicated that there was a more significant reduction in leptin level with a longer follow-up time. OAGB had a greater effect on increasing adiponectin level compared with other procedures. SG procedure would bring about reduced ghrelin, while BPD resulted in increased ghrelin. Meta-regression analysis found that publication year, study design, number of patients, preoperative age, preoperative BMI, and quality assessment score were not significantly related to change in leptin, adiponectin, and ghrelin levels.

CONCLUSION

Bariatric surgery was associated with a significant decrease in leptin, ghrelin, CRP, IL-6, Hs-CRP, TNF-α, and IL-1β, as well as increase in adiponectin, GLP-1, and PYY levels.

Interleukin-36α is elevated in diffuse systemic sclerosis and may potentiate fibrosis

Systemic sclerosis (SSc) is an autoimmune prototypical connective tissues disease that results in alterations in vasculature, inflammation and fibrosis of the skin. Interleukin-1 family cytokines has been implicated in the disease including IL-1. IL-36α is an IL-1 family member that is clearly implicated in psoriatic skin disease but its role in systemic sclerosis disease is not clear. The aim of this work is to evaluate the levels and role of IL-36α in systemic sclerosis. Early diffuse SSc patients sera was isolated along with healthy controls and IL-36 levels quantified by ELISA. In vitro analysis was also undertaken with primary dermal fibroblasts with recombinant IL-36α and keratinocyte cells were also incubated with IL-36α. Cytokines were measured by ELISA. Serum IL-36 was significantly elevated compared to healthy controls. Elevated neutrophil elastase was also elevated in the matched sera. IL-36 was not directly pro-fibrotic in dermal fibroblasts but did induce pro-inflammatory cytokines that were dependant on the MAPK pathway for their release. IL-36α also led to release of CCL20 and CCL2 in keratinocytes which may potentiate fibrosis. IL-36α is elevated in SSc serum and whilst not directly pro-fibrotic it may through keratinocytes, potentiate fibrosis through keratinocyte-immune fibroblast cross-talk.

Association between red blood cell distribution width‐to‐albumin ratio and diabetic retinopathy

Background

Diabetes mellitus (DM) has shown a trend of reaching pandemic levels in the world. Chronic inflammation is a key factor in the development of diabetic retinopathy (DR). Red blood cell distribution width‐to‐albumin ratio (RA) is used to assess immune status and the immune response. Our study was conducted to assess the association between DR and RA levels to determine the value of RA in predicting DR.

Methods

The data came from the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2006, The RA was calculated as the Red Blood Cell Distribution Width/Albumin Ratio. Multivariable logistic regression and propensity score‐matched analysis were used to examine the association between RA and DR levels.

Results

The clinical and demographic features of the 1,751 patients with DM. The eligible participants included 874 females and 870 males with mean age 62.2 ± 14.0 years, and mean RA 3.2 ± 0.5. RA ≥ 2.9659 was a risk factor for DR (OR = 1.66 95% CI: 1.31–2.11, p < 0.0001). After adjusting for age, sex, race, education, marital status, ratio of family income to poverty, body mass index, fasting glucose, hypertension, and coronary heart disease, RA ≥ 2.9659 was an independent risk factor for DR (OR = 1.64, 95% CI: 1.23–2.19, p = 0.0008). The propensity score‐matched analysis also showed that high RA was an independent risk factor for DR.

Conclusions

Our study shows that RA is a risk factor for patients with DR. The findings of this study should be validated the role of RA in DR in diabetic patients.