Adipose tissue inflammation: novel insight into the role of macrophages and lymphocytes

Relationships between obesity and prevalence of gout in patients with type 2 diabetes mellitus: a cross-sectional population-based study

BACKGROUND

The purpose of this study was to investigate the relationships between generalized, abdominal, and visceral fat obesity and the prevalence of gout in patients with type 2 diabetes mellitus (T2DM).

METHODS

Data were obtained from the electronic medical databases of the National Metabolic Management Center (MMC) of Yuhuan Second People's Hospital and Taizhou Central Hospital (Taizhou University Hospital) between September 2017 and June 2023. Four obesity indicators were analyzed: waist circumference (WC), waist-to-hip ratio (WHR), body mass index (BMI), and visceral fat area (VFA). The relationships between these parameters and gout prevalence were analyzed using multivariate logistic regression and restricted cubic spline (RCS) analyses. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic efficacy of the four parameters for gout.

RESULTS

This cross-sectional study enrolled 10,535 participants (600 cases and 9,935 controls). Obesity was more common in patients with gout, and the obesity indicators were markedly higher in this group. After adjustment for confounders, obesity, as defined by BMI, WC, WHR, and VFA, was found to be associated with greater gout prevalence, with odds ratios (OR) of 1.775, 1.691, 1.858, and 1.578, respectively (P < 0.001). The gout odds ratios increased markedly in relation to the obesity indicator quartiles (P-value for trend < 0.001), and the obesity indicators were positively correlated with gout prevalence, as shown using RCS. The area under the ROC curve values for BMI, WC, WHR, and VFA were 0.629, 0.651, 0.634, and 0.633, respectively.

CONCLUSION

Obesity-whether general, abdominal, or visceral fat obesity-was positively linked with elevated gout risk. But uncovering the causality behind the relationship requires further prospective study. Obesity indicators (BMI, WC, WHR, and VFA) may have potential value for diagnosing gout in clinical practice.

Gene expression alterations of purinergic signaling components in obesity-associated intestinal low-grade inflammation in type 2 diabetes

Intestinal low-grade inflammation induced by a high-fat diet has been found to detonate chronic systemic inflammation, which is a hallmark of obesity, and precede the apparition of insulin resistance, a key factor for developing type 2 diabetes (T2D). Aberrant purinergic signaling pathways have been implicated in the pathogenesis of inflammatory bowel disease and other gastrointestinal diseases. However, their role in the gut inflammation associated with obesity and T2D remains unexplored. C57BL/6 J mice were fed a cafeteria diet for 21 weeks and received one injection of streptozotocin in their sixth week into the diet. The gene expression profile of purinergic signaling components in colon tissue was assessed by RT-qPCR. Compared to control mice, the treated group had a significant reduction in colonic length and mucosal and muscular layer thickness accompanied by increased NF-κB and IL-1β mRNA expression. Furthermore, colonic P2X2, P2X7, and A3R gene expression levels were lower, while the P2Y2, NT5E, and ADA expression levels increased. In conclusion, these data suggest that these purinergic signaling components possibly play a role in intestinal low-grade inflammation associated with obesity and T2D and thus could represent a novel therapeutic target for the treatment of the metabolic complications related to these diseases.

Oxidative and DNA damage in obese patients undergoing bariatric surgery: A one-year follow-up study

The pathogenesis of obesity and related comorbidities has long been associated with oxidative stress. The excess of adipose tissue contributes to the production of free radicals that sustain both a local and a systemic chronic inflammatory state, whereas its reduction can bring to an improvement in inflammation and oxidative stress. In our work, using the fluorescent lipid probe BODIPY® 581/591 C11 and the γH2AX foci assay, a well-known marker of DNA double strand breaks (DSB), we evaluated the extent of cell membrane oxidation and DNA damage in peripheral blood lymphocytes of normal weight (NW) controls and obese patients sampled before and after bariatric surgery. Compared to NW controls, we observed a marked increase in both the frequencies of oxidized cells or nuclei exhibiting phosphorylation of histone H2AX in preoperatory obese patients. After bariatric surgery, obese patients, resampled over one-year follow-up, improved oxidative damage and reduced the presence of DSB. In conclusion, the present study highlights the importance for obese patients undergoing bariatric surgery to also monitor these molecular markers during their postoperative follow-up.

Mechanisms linking bariatric surgery to adipose tissue, glucose metabolism, fatty liver disease and gut microbiota

PURPOSE

In the last 20 years, bariatric surgery has achieved an important role in translational and clinical research because of obesity comorbidities. Initially, a tool to lose weight, bariatric surgery now has been shown to be involved in several metabolic pathways.

METHODS

We conducted a narrative review discussing the underlying mechanisms that could explain the impact of bariatric surgery and the relationship between obesity and adipose tissue, T2D, gut microbiota, and NAFLD.

RESULTS

Bariatric surgery has an impact in the relation between obesity and type 2 diabetes, but in addition  it induces the white-to-brown adipocyte trans-differentiation, by enhancing thermogenesis. Another issue is the connection of bariatric surgery with the gut microbiota and its role in the complex mechanism underlying weight gain.

CONCLUSION

Bariatric surgery modifies gut microbiota, and these modifications influence lipid metabolism, leading to improvement of non-alcoholic fatty liver disease.

Expression of Steroid Receptor RNA Activator 1 (SRA1) in the Adipose Tissue Is Associated with TLRs and IRFs in Diabesity

Steroid receptor RNA activator gene (SRA1) emerges as a player in pathophysiological responses of adipose tissue (AT) in metabolic disorders such as obesity and type 2 diabetes (T2D). We previously showed association of the AT SRA1 expression with inflammatory cytokines/chemokines involved in metabolic derangement. However, the relationship between altered adipose expression of SRA1 and the innate immune Toll-like receptors (TLRs) as players in nutrient sensing and metabolic inflammation as well as their downstream signaling partners, including interferon regulatory factors (IRFs), remains elusive. Herein, we investigated the association of AT SRA1 expression with TLRs, IRFs, and other TLR-downstream signaling mediators in a cohort of 108 individuals, classified based on their body mass index (BMI) as persons with normal-weight (N = 12), overweight (N = 32), and obesity (N = 64), including 55 with and 53 without T2D. The gene expression of SRA1, TLRs-2,3,4,7,8,9,10 and their downstream signaling mediators including IRFs-3,4,5, myeloid differentiation factor 88 (MyD88), interleukin-1 receptor-associated kinase 1 (IRAK1), and nuclear factor-κB (NF-κB) were determined using qRT-PCR and SRA1 protein expression was determined by immunohistochemistry. AT SRA1 transcripts' expression was significantly correlated with TLRs-3,4,7, MyD88, NF-κB, and IRF5 expression in individuals with T2D, while it associated with TLR9 and TRAF6 expression in all individuals, with/without T2D. SRA1 expression associated with TLR2, IRAK1, and IRF3 expression only in individuals with obesity, regardless of diabetes status. Furthermore, TLR3/TLR7/IRAK1 and TLR3/TLR9 were identified as independent predictors of AT SRA1 expression in individuals with obesity and T2D, respectively. Overall, our data demonstrate a direct association between the AT SRA1 expression and the TLRs together with their downstream signaling partners and IRFs in individuals with obesity and/or T2D.

Th1/Th2 Balance in Young Subjects: Relationship with Cytokine Levels and Metabolic Profile

Purpose

We aim to identify Th1 and Th2 cell clusters in young subjects, including their clinical and metabolic characteristics and the Th1/Th2 balance.

Patients and Methods

A total of 100 participants were included. The frequencies of Th1 and Th2 cells in peripheral blood were determined by flow cytometry. Serum C-reactive protein was measured using a turbidimetric assay, and insulin levels were quantified with an enzyme-linked immunosorbent assay. Circulating cytokine levels were analyzed using a multiplex system.

Results

A cluster analysis was performed to determine the Th1/Th2 balance in a group of young people, and 3 clusters were formed with the following characteristics: 1) subjects with a higher prevalence of hyperglycemia (38%), dyslipidemia (38–75%), and insulin resistance (50%), as well as a higher percentage of Th1 cells and Th1/Th2 ratio, including elevated IFN-ɣ levels; 2) subjects with a lower prevalence of hyperglycemia (23%) and insulin resistance (15.4%), but a higher prevalence of dyslipidemia (8–85%) with a predominance of Th2 cells, and lower Th1/Th2 ratio; 3) subjects with a lower prevalence of hyperglycemia (6%), insulin resistance (41%), and dyslipidemia (10–63%), as well as a balance of Th1 and Th2 cells and lower Th1/Th2 ratio, including low IFN-ɣ levels. Positive correlations between Th1 cells with IFN-γ, IL-12, and IL-1β and between Th2 cells with IFN-γ, IL-2, and IL-4 were found (p < 0.05). A significant increase in Th1 cells was observed in the presence of hyperglycemia and high LDL-C levels, as well as increased Th2 cells in the absence of abdominal obesity and high blood pressure, including low HDL-C levels. The Th1/Th2 ratio was higher in the group with high cardiometabolic risk (p = 0.03).

Conclusion

Th1/Th2 balance is related to metabolic abnormalities that may occur in young population, and thus the timely identification of different phenotypes may help predict an increased cardiometabolic risk.

AdipoRon and Other Adiponectin Receptor Agonists as Potential Candidates in Cancer Treatments

The high mortality rate together with an ever-growing number of annual cases have defined neoplastic disorders as “the real 21st-century disease”. Its dubious distinction also results from conventional therapy failure, which has made cancer an orphan disease. Therefore, innovative and alternative therapeutic strategies are mandatory. The ability to leverage human naturally occurring anti-tumor defenses has always represented a fascinating perspective, and the immuno blockage approval in cancer treatment represents in timeline the latest success. As a multifunctional organ, adipose tissue releases a large amount of adipokines having both carcinogenic and antitumor properties. The negative correlation between serum levels and risk for developing malignancies, as well as the huge number of existing preclinical studies, have identified adiponectin as a potential anticancer adipokine. Nevertheless, its usage in clinical has constantly clashed with the inability to reproduce a mimic synthetic compound. Between 2011 and 2013, two distinct adiponectin receptor agonists were recognized, opening new scenarios even in cancer. Here, we review the first orally active adiponectin receptor agonists AdipoRon, from the discovery to the anticancer evidence. Including our latest findings in osteosarcoma models, we summarize AdipoRon and other existing agonists state-of-art, questioning about the feasibility assessment of this strategy in cancer treatment.

GATA-3 as a Potential Therapeutic Target for Insulin Resistance and Type 2 Diabetes Mellitus

Impaired adipogenesis plays an important role in the development of obesity-associated insulin resistance and type 2 diabetes as it leads to ectopic fat deposition. The anti-adipogenic transcription factor GATA-3 was identified as one of the potential molecular targets responsible for the impairment of adipogenesis. The expression of GATA-3 is higher in insulinresistant obese individuals compared to BMI-matched insulin-sensitive counterparts. Adipose tissue inflammation is a crucial mediator of this process. Hyperglycemia mediates the activation of the immune system, partially through upregulation of GATA- 3, causing exacerbation of the inflammatory state associated with obesity. This review discusses the evidence supporting the inhibition of GATA-3 as a useful therapeutic strategy in obesity-associated insulin resistance and type 2 diabetes, through up-regulation adipogenesis and amelioration of the immune response.

Exercise Training Reduces Inflammation of Adipose Tissue in the Elderly: Cross-Sectional and Randomized Interventional Trial

CONTEXT

Metabolic disturbances and a pro-inflammatory state associated with aging and obesity may be mitigated by physical activity or nutrition interventions.

OBJECTIVE

The aim of this study is to assess whether physical fitness/exercise training (ET) alleviates inflammation in adipose tissue (AT), particularly in combination with omega-3 supplementation, and whether changes in AT induced by ET can contribute to an improvement of insulin sensitivity and metabolic health in the elderly.

DESIGN, PARTICIPANTS, MAIN OUTCOME MEASURES

The effect of physical fitness was determined in cross-sectional comparison of physically active/physically fit (trained) and sedentary/less physically fit (untrained) older women (71 ± 4 years, n = 48); and in double-blind randomized intervention by 4 months of ET with or without omega-3 (Calanus oil) supplementation (n = 55). Physical fitness was evaluated by spiroergometry (maximum graded exercise test) and senior fitness tests. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp. Samples of subcutaneous AT were used to analyze mRNA gene expression, cytokine secretion, and immune cell populations.

RESULTS

Trained women had lower mRNA levels of inflammation and oxidative stress markers, lower relative content of CD36+ macrophages, and higher relative content of γδT-cells in AT when compared with untrained women. Similar effects were recapitulated in response to a 4-month ET intervention. Content of CD36+ cells, γδT-cells, and mRNA expression of several inflammatory and oxidative stress markers correlated to insulin sensitivity and cardiorespiratory fitness.

CONCLUSIONS

In older women, physical fitness is associated with less inflammation in AT. This may contribute to beneficial metabolic outcomes achieved by ET. When combined with ET, omega-3 supplementation had no additional beneficial effects on AT inflammatory characteristics.

Refinement and Validation of the Head and Neck Lymphedema and Fibrosis Symptom Inventory

PURPOSE

Lymphedema and fibrosis (LEF) are common yet overlooked late effects of head and neck cancer and its therapy. Lack of reliable and valid measures of head and neck LEF is a critical barrier to the timely identification and management of head and neck LEF. To fill this gap, we developed and pilot tested a 64-item patient-reported outcome measure ( Lymphedema Symptom Intensity and Distress Survey-Head and Neck, LSIDS-H&N). This article aims to report the process of further validation and refinement of the tool.

METHODS AND MATERIALS

A prospective, longitudinal study was conducted, and 120 patients with oral cavity and oropharyngeal cancer were recruited. Participants completed the LSIDS-H&N at pretreatment, end of treatment, and every 3 months up to 12 months after treatment. SAS PROC VARCLUS was used to generate preliminary clusters of item responses. Internal consistency of the item responses within each cluster was assessed using Cronbach's alpha.

RESULTS

A total of 117 patients completed the study. The participants reported that the LSIDS-H&N was easy to understand and captured their symptoms and medical conditions. However, >50% of participants indicated that the survey was burdensome due to length. Thus, we proceeded with item reduction, and the shortened tool (33-item) was named Head and Neck Lymphedema and Fibrosis Symptom Inventory (HN-LEF Symptom Inventory). The subsequent exploration of symptom clusters identified 7 symptom domain clusters (eg, soft tissue and neurologic toxicity), all of which demonstrated good internal consistency.

CONCLUSIONS

The HN-LEF Symptom Inventory has been carefully developed and refined to allow clinicians and researchers to capture LEF-associated symptom burden and function impairments. Additional rigorous psychometric testing of the tool is ongoing to further validate the strength and internal validity of this tool.

Late Soft Tissue Complications of Head and Neck Cancer Therapy: Lymphedema and Fibrosis

Head and neck cancer and its treatment result in soft tissue damage secondary to lymphedema and fibrosis. Lymphedema is the result of pathological accumulation of interstitial fluid in tissues. It is caused by the inability of the lymphatic system to transport lymph fluid from the tissues to the central circulatory system and is manifested clinically by tissue swelling. Fibrosis is defined as an overaccumulation of fibrotic tissues within the skin and soft tissues after a single or repetitive injury and is characterized by hardening of the soft tissues with associated loss of elasticity. Lymphedema and fibrosis are common yet overlooked late effects of head and neck cancer and its therapy. They may result in profound long-term symptom burden, loss of critical functions, and altered quality of life. The following review will discuss the current pathobiology, clinical manifestations, and future directions for research related to lymphedema and fibrosis.

Functional polarization of macrophages of rats with progesterone-induced obesity treated with melanin from the Antarctic yeast Nadsoniella nigra

Progesterone-induced obesity develops in women who use this drug for contraception and the menopause treatment, though its mechanisms remain poorly understood. We studied functional M1 and M2 polarizations of the abdominal cavity macrophages of rats with progesterone induced obesity during 28 days of administration. The effect of melanin from the Antarctic yeast Nadsoniella nigra (Chaetothyriales, Herpotrichiellaceae, Nadsoniella Issatsch, 1914) was investigated. The NO level was determined by the accumulation of nitrites, ROS level was estimated by the NBT-test, arginase activity was assayed by the reaction of L-arginine hydrolysis. The body weights of rats administrated progesterone increased by 27% and continued to increase one month after withdrawal of progesterone (55% higher than control). Melanin prevents the weight gain when administered during one month after progesterone withdrawal. The NO production by peritoneal macrophages of obese animals intensified by 31% indicating their polarization towards pro-inflammatory M1 type. Production of ROS did not change. A 14% increase in arginase activity was observed, indicating the inhibition of M2 (anti-inflammatory) polarization. In the progesterone withdrawal group all these rates significantly decreased, indicating a reduction in the functional activity of peritoneal macrophages’. Melanin decreased the NO and ROS production by 60% and 18% respectively in comparison with the progesterone group and unexpectedly reduced arginase activity. Our data provide evidence of the spread of inflammation in response to progesterone-induced obesity. Peritoneal macrophages are involved in the inflammation in obesity, undergoing polarization towards the pro-inflammatory phenotype. The long-term consequences of such inflammation include the continuation of weight gain and likely the development of systemic inflammation associated with the exhaustion of the functional capacity of peritoneal cavity macrophages. Melanin has an anti-obesity effect and exhibits anti-inflammatory properties preventing progesterone-induced weight gain and macrophage M1 polarization. This requires detailed elucidation and can be valuable in designing countermeasures to prevent obesity outcomes.

White cell counts in relation to mortality in a general population of cohort study in the Netherlands: a mediating effect or not?

BACKGROUND

White cell count (WCC) is a clinical marker of inflammation. Data are limited regarding the association of total and differential WCC with risk of mortality, and its role related with smoking and body mass index (BMI).

METHODS

A total of 14 433 participants (4150 men; 10 283 women; average age 47.3±11.8 years) from the Dutch European Prospective Investigation into Cancer and Nutrition-Netherlands cohort were included. The associations between prediagnostic total WCC and its subtypes and risk of all-cause, cancer and cardiovascular disease (CVD) mortality were assessed. The role of WCC related with smoking and BMI on mortality was further explored. Multivariate Cox regression models were performed to estimate the HR and 95% CI.

RESULTS

After an average follow-up of 15.8 years, a total of 936 death cases were identified (466 cancer; 179 CVD; 291 other causes). Statistically significant graded associations between total WCC, and counts of lymphocytes, monocytes, neutrophils and eosinophils and risk of total mortality were observed. These associations were more apparent in current smokers. Strong associations for all-cause mortality or cancer mortality were observed in subjects with BMI ≥25 kg/m², ever smoking and elevated WCC (HR 3.92, 95% CI 2.76 to 5.57; HR 3.93, 95% CI 2.30 to 6.72). WCC partly mediated the associations between smoking or BMI and all-cause mortality.

CONCLUSIONS

Prediagnostic WCC and its subtypes are associated with all-cause, cancer and CVD mortality risk. It may play a partially mediate role on the association between smoking or obesity and mortality.

Adiponectin as Link Factor between Adipose Tissue and Cancer

Adipose tissue is a key regulator of energy balance playing an active role in lipid storage as well as in synthesizing several hormones directly involved in the pathogenesis of obesity. Obesity represents a peculiar risk factor for a growing list of cancers and is frequently associated to poor clinical outcome. The mechanism linking obesity and cancer is not completely understood, but, amongst the major players, there are both chronic low-grade inflammation and deregulation of adipokines secretion. In obesity, the adipose tissue is pervaded by an abnormal number of immune cells that create an inflammatory environment supporting tumor cell proliferation and invasion. Adiponectin (APN), the most abundant adipokine, shows anti-inflammatory, anti-proliferative and pro-apoptotic properties. Circulating levels of APN are drastically decreased in obesity, suggesting that APN may represent the link factor between obesity and cancer risk. The present review describes the recent advances on the involvement of APN and its receptors in the etiology of different types of cancer.

Chemokine gene polymorphisms association with increased risk of type 2 diabetes mellitus in Tatar ethnic group, Russia

Recent studies have shown that chemokines play an important role in the development of chronic inflammation in adipose tissue, obesity pathogenesis, glucose intolerance and type 2 diabetes. It has also been revealed that some SNPs in chemokine genes are associated with obesity, insulin resistance, type 2 diabetes and diabetes complications in different ethnic groups. The aim of this study was to determine the associations between SNPs in chemokine genes and type 2 diabetes in participants of Tatar ethnic group, living in Bashkortostan. Case-control and cross-sectional study were included in our study design. Five SNPs were genotyped in 440 type 2 diabetes (160 men and 280 women), 58.8 ± 9.2 years old (mean ± SD), BMI 29.3 ± 3.9 kg/m² (mean ± SD) patients of Tatar ethnicity, and a control group of 500 Tatars (180 men and 320 women), 55.2 ± 11.6 years old (mean ± SD), BMI 25.9 ± 4.3 kg/m² (mean ± SD). The SNPs rs6749704 in CCL20 [odds ratio (OR) = 2.77 (95% CI 1.81-4.25), р = 0.0001], rs2107538 in CCL5 [odds ratio (OR) = 1.80 (95% CI 1.46-2.22), p = 0.0001] were significantly associated with type 2 diabetes. Regression analysis revealed that rs1696941 in CCL11 was associated with the onset age and duration of type 2 diabetes as well as with HbA_1c level (p = 0.034, p = 0.036 and p = 0.0054, respectively). The SNPs rs223828 in CCL17 and rs6749704 in CCL20 were correlated with obesity as estimated by BMI (p = 0.0004, p = 0.029, respectively). Rs223828 in CCL17 revealed the association with postprandial glucose level (p = 0.024) and HbA_1c (p = 0.008). These data demonstrate that variants of chemokine genes are associated with type 2 diabetes and obesity of Tatar ethnic group inhabiting Bashkortostan Republic. Novel associations of the polymorphic loci in CCL20 (rs6749704) and CCL5 (rs2107538) genes with type 2 diabetes had been identified as a result of the conducted research.

Conditioned medium from contracting skeletal muscle cells reverses insulin resistance and dysfunction of endothelial cells

OBJECTIVE

Obese adipose tissue has been characterized with chronic inflammation associated with elevated secretion of inflammatory cytokines and declined secretion of anti-inflammatory cytokines which can impair endothelial function in an endocrine manner. Adipose tissue hypoxia plays a role in the changes of cytokines. Physical exercise/muscle contraction may help preventing cardiovascular disease through improving insulin resistance and endothelium function. However the mechanism is unclear. Skeletal muscle is an endocrine tissue. Contracting muscles secrete myokines which may play roles in the beneficial effect of exercise. In this study, the conditioned medium from electrical pulse stimulation (EPS) regulated skeletal muscle cells was used to explore the mechanism of contraction on endothelial dysfunction and insulin resistance induced by conditioned medium from hypoxic adipocytes.

METHODS

3T3-L1 adipocytes were incubated under normoxia or hypoxia condition, respectively. The supernatant was collected as adipocyte conditioned medium (CM-N and CM-H). C2C12 mouse skeletal muscle cells were stimulated with EPS for 12 h. The supernatant was collected as muscle cells conditioned medium (CM-EPS). Human umbilical vein endothelial cells (HUVECs) were incubated with adipocyte CM and muscle cells CM together. Macrophages migration to HUVECs was detected with transwell system. The mRNA expressions of E-selectin, ICAM-1, MCP-1 and IL-6 were measured by real-time PCR. The phosphorylation of IKKα/β, NF-κB, Akt, AMPK, eNOS and SOCS3 protein levels were detected by Western blot. Concentration of NO was measured by ELISA kit. HUVECs apoptosis was detected by flow cytometry.

RESULTS

CM-EPS reduced the increase of mRNA expressions of E-selectin, ICAM-1, MCP-1 and IL-6 in HUVECs induced by CN-H. The phosphorylations of IKKα/β and NF-κB, SOCS3 protein level and endothelial cells apoptosis, which were raised by CM-H, were significantly reduced by CM-EPS. CM-EPS reversed the effects of CM-H on Akt and eNOS phosphorylations and NO production in HUVECs. CM-EPS directly stimulated the phosphorylation of AMPK, which caused the following phosphorylation of eNOS in HUVECs.

CONCLUSION

In summary, CM-EPS reversed endothelial cells inflammation, apoptosis, insulin resistance and dysfunction induced by CM-H.

Effect of energy restriction and physical exercise intervention on phenotypic flexibility as examined by transcriptomics analyses of mRNA from adipose tissue and whole body magnetic resonance imaging

Overweight and obesity lead to changes in adipose tissue such as inflammation and reduced insulin sensitivity. The aim of this study was to assess how altered energy balance by reduced food intake or enhanced physical activity affect these processes. We studied sedentary subjects with overweight/obesity in two intervention studies, each lasting 12 weeks affecting energy balance either by energy restriction (~20% reduced intake of energy from food) in one group, or by enhanced energy expenditure due to physical exercise (combined endurance‐ and strength‐training) in the other group. We monitored mRNA expression by microarray and mRNA sequencing from adipose tissue biopsies. We also measured several plasma parameters as well as fat distribution with magnetic resonance imaging and spectroscopy. Comparison of microarray and mRNA sequencing showed strong correlations, which were also confirmed using RT‐PCR. In the energy restricted subjects (body weight reduced by 5% during a 12 weeks intervention), there were clear signs of enhanced lipolysis as monitored by mRNA in adipose tissue as well as plasma concentration of free‐fatty acids. This increase was strongly related to increased expression of markers for M1‐like macrophages in adipose tissue. In the exercising subjects (glucose infusion rate increased by 29% during a 12‐week intervention), there was a marked reduction in the expression of markers of M2‐like macrophages and T cells, suggesting that physical exercise was especially important for reducing inflammation in adipose tissue with insignificant reduction in total body weight. Our data indicate that energy restriction and physical exercise affect energy‐related pathways as well as inflammatory processes in different ways, probably related to macrophages in adipose tissue.

Obesity and Pancreatic Cancer

Pancreatic cancer has few known risk factors, providing little in the way of prevention, and is the most rapidly fatal cancer with 7 % survival rate at 5 years. Obesity has surfaced as an important risk factor for pancreatic cancer as epidemiological studies with strong methodological designs have removed important biases and solidified the obesity associations. Moreover, studies indicate that obesity early in adulthood is strongly associated with future risk of pancreatic cancer and that abdominal obesity is an independent risk factor. There is increasing evidence suggesting long-standing diabetes type 2 and insulin resistance are important etiological factors of this disease, providing a strong mechanistic link to obesity. The challenge remains to determine whether intended weight loss in midlife will reduce risk of pancreatic cancer and to elucidate the complex underlying pathways directly involved with risk.

Quantitative analysis of rat adipose tissue cell recovery, and non-fat cell volume, in primary cell cultures

BACKGROUND

White adipose tissue (WAT) is a complex, diffuse, multifunctional organ which contains adipocytes, and a large proportion of fat, but also other cell types, active in defense, regeneration and signalling functions. Studies with adipocytes often require their isolation from WAT by breaking up the matrix of collagen fibres; however, it is unclear to what extent adipocyte number in primary cultures correlates with their number in intact WAT, since recovery and viability are often unknown.

EXPERIMENTAL DESIGN

Epididymal WAT of four young adult rats was used to isolate adipocytes with collagenase. Careful recording of lipid content of tissue, and all fraction volumes and weights, allowed us to trace the amount of initial WAT fat remaining in the cell preparation. Functionality was estimated by incubation with glucose and measurement of glucose uptake and lactate, glycerol and NEFA excretion rates up to 48 h. Non-adipocyte cells were also recovered and their sizes (and those of adipocytes) were measured. The presence of non-nucleated cells (erythrocytes) was also estimated.

RESULTS

Cell numbers and sizes were correlated from all fractions to intact WAT. Tracing the lipid content, the recovery of adipocytes in the final, metabolically active, preparation was in the range of 70-75%. Cells showed even higher metabolic activity in the second than in the first day of incubation. Adipocytes were 7%, erythrocytes 66% and other stromal (nucleated cells) 27% of total WAT cells. However, their overall volumes were 90%, 0.05%, and 0.2% of WAT. Non-fat volume of adipocytes was 1.3% of WAT.

CONCLUSIONS

The methodology presented here allows for a direct quantitative reference to the original tissue of studies using isolated cells. We have also found that the "live cell mass" of adipose tissue is very small: about 13 µL/g for adipocytes and 2 µL/g stromal, plus about 1 µL/g blood (the rats were killed by exsanguination). These data translate (with respect to the actual "live cytoplasm" size) into an extremely high metabolic activity, which make WAT an even more significant agent in the control of energy metabolism.

Depot- and gender-specific expression of NLRP3 inflammasome and toll-like receptors in adipose tissue of cancer patients

Gender difference in obesity-associated cardiovascular complication could be derived from divergent chronic inflammation. We evaluated depot- and gender-specific regulation of the innate immune system in human adipose tissues. Pair samples were obtained from subcutaneous (SAT) and visceral adipose tissue (VAT) during elective surgery (Male: 35; Female: 27). Expressions of pro- and anti-inflammatory adipocytokines were evaluated by semi-quantitative qPCR. Adipose cell-size distribution was obtained from tissue samples fixed in osmium tetroxide and analyzed by Beckman Coulter Multisizer. Levels of adiponectin were higher in SAT and VAT of female than those of male (P < 0.001 and P = 0.011, respectively). NLRP3, IL1β-IL18, TLR2 were comparable in SAT and VAT between genders. However, TLR4 and TLR9 were increased in female SAT and VAT and HMGB1 in female VAT. Levels of adiponectin were not correlated with mean diameter of adipocyte (φ, μm) in SAT and VAT of male, but negatively well correlated in those of female (r = -0.392 and r = -0.616). Such negative correlations were also observed between levels of TLR2, TLR4, and HMGB1 and φ in female. Levels of NLRP3 and IL1β were positively correlated with φ in male, but not in female. In conclusion, Innate signals were differentially expressed in male and female adipose tissues, suggesting that the depot- and gender-specific signals could be related to gender difference in chronic inflammation. © 2016 BioFactors, 42(4):397-406, 2016.

Galectin-12 enhances inflammation by promoting M1 polarization of macrophages and reduces insulin sensitivity in adipocytes

Galectin-12 is a member of an animal lectin family with affinity for β-galactosides and containing consensus amino acid sequences. Here, we found that galectin-12 was expressed in macrophages and thus aimed to determine how galectin-12 affects inflammation and macrophage polarization and activation. The ablation of galectin-12 did not affect bone marrow cells to differentiate into macrophages, but reduced phagocytic activity against Escherichia coli and lowered the secretion of nitric oxide. The ablation of galectin-12 also resulted in the polarization of macrophages into the M2 direction, as indicated by increases in the levels of M2 markers, namely, resistin-like β (FIZZ1) and chitinase 3-like 3 (Ym1), as well as a reduction in the expression levels of a number of M1 pro-inflammatory cytokines. We found that the diminished expression of pro-inflammatory cytokines in macrophages resulting from galectin-12 deletion was due to reduced activation of IKKα/β, Akt and ERK, which in turn caused decreased activation of NF-κB and activator protein 1. The activation of STAT3 was much higher in Gal12(-/-) macrophages activated by lipopolysaccharide, which was correlated with higher levels of IL-10. Adipocytes showed higher insulin sensitivity when treated with Gal12(-/-) macrophage-conditioned media than those treated with Gal12(+/+) macrophages. We conclude galectin-12 negatively regulates macrophage polarization into the M2 population, resulting in enhanced inflammatory responses and also in turn causing decreased insulin sensitivity in adipocytes. This has implications in the treatment of a wide spectrum of metabolic disorders.

Crosstalk between intestinal microbiota, adipose tissue and skeletal muscle as an early event in systemic low-grade inflammation and the development of obesity and diabetes

Obesity is associated with a systemic chronic low-grade inflammation that contributes to the development of metabolic disorders such as cardiovascular diseases and type 2 diabetes. However, the etiology of this obesity-related pro-inflammatory process remains unclear. Most studies have focused on adipose tissue dysfunctions and/or insulin resistance in skeletal muscle cells as well as changes in adipokine profile and macrophage recruitment as potential sources of inflammation. However, low-grade systemic inflammation probably involves a complex network of signals interconnecting several organs. Recent evidences have suggested that disturbances in the composition of the gut microbial flora and alterations in levels of gut peptides following the ingestion of a high-fat diet may be a cause of low-grade systemic inflammation that may even precede and predispose to obesity, metabolic disorders or type 2 diabetes. This hypothesis is appealing because the gastrointestinal system is first exposed to nutrients and may thereby represent the first link in the chain of events leading to the development of obesity-associated systemic inflammation. Therefore, the present review will summarize the latest advances interconnecting intestinal mucosal bacteria-mediated inflammation, adipose tissue and skeletal muscle in a coordinated circuitry favouring the onset of a high-fat diet-related systemic low-grade inflammation preceding obesity and predisposing to metabolic disorders and/or type 2 diabetes. A particular emphasis will be given to high-fat diet-induced alterations of gut homeostasis as an early initiator event of mucosal inflammation and adverse consequences contributing to the promotion of extended systemic inflammation, especially in adipose and muscular tissues.

Acute Myocardial Infarction Is a Risk Factor for New Onset Diabetes in Patients with Coronary Artery Disease

Objective

To test the hypothesis that acute myocardial infarction (AMI) might accelerate development of new onset diabetes in patients with coronary artery disease independent of known risk factors.

Methods

We conducted a retrospective cohort study within COACT (CathOlic medical center percutAneous Coronary inTervention) registry. From a total of 9,127 subjects, 2,036 subjects were diabetes naïve and followed up for at least one year with both index and follow-up laboratory data about diabetes. Cox proportional hazard model was used to derive hazard ratios (HRs) and 95% confidence interval (CI) for new onset diabetes associated with AMI in univariate and multivariate analysis after adjusting several covariates.

Results

The overall hazard for diabetes was higher in AMI compared to non-AMI patients (p by log rank <0.01) with HR of 1.78 and 95% CI of 1.37–2.32 in univariate analysis. This association remained significant after adjusting covariates (HR, 1.54; 95% CI, 1.14–2.07; p<0.01). AMI was an independent predictor for higher quartile of WBC count in multivariate ordinal logistic regression analysis (OR, 6.75; 95% CI, 5.53–8.22, p<0.01). In subgroup analysis, the diabetogenic effect of AMI was more prominent in the subgroup without MetS compared to MetS patients (p for interaction<0.05). Compared to the reference group of non-AMI+nonMetS, the group of AMI+non-MetS (HR, 2.44; 95% CI, 1.58–3.76), non-AMI+MetS (HR, 3.42; 95% CI, 2.34–4.98) and AMI+MetS (HR, 4.12; 95% CI, 2.67–6.36) showed higher HR after adjusting covariates. However, the hazard was not different between the non-AMI+MetS and AMI+non-MetS groups.

Conclusions

AMI patients have a greater risk of new-onset diabetes when compared to non AMI patients, especially those with mild metabolic abnormalities.

Long-term pathological consequences of prenatal infection: beyond brain disorders

Prenatal immunological adversities such as maternal infection have been widely acknowledged to contribute to an increased risk of neurodevelopmental brain disorders. In recent years, epidemiological and experimental evidence has accumulated to suggest that prenatal exposure to immune challenges can also negatively affect various physiological and metabolic functions beyond those typically associated with primary defects in CNS development. These peripheral changes include excessive accumulation of adipose tissue and increased body weight, impaired glycemic regulation and insulin resistance, altered myeloid lineage development, increased gut permeability, hyperpurinergia, and changes in microbiota composition. Experimental work in animal models further suggests that at least some of these peripheral abnormalities could directly contribute to CNS dysfunctions, so that normalization of peripheral pathologies could lead to an amelioration of behavioral deficits. Hence, seemingly unrelated central and peripheral effects of prenatal infection could represent interrelated pathological entities that emerge in response to a common developmental stressor. Targeting peripheral abnormalities may thus represent a valuable strategy to improve the wide spectrum of behavioral abnormalities that can emerge in subjects with prenatal infection histories.

Gut Microbiome and Obesity: A Plausible Explanation for Obesity

Obesity is a multifactorial disorder that results in excessive accumulation of adipose tissue. Although obesity is caused by alterations in the energy consumption/expenditure balance, the factors promoting this disequilibrium are incompletely understood. The rapid development of new technologies and analysis strategies to decode the gut microbiota composition and metabolic pathways has opened a door into the complexity of the guest-host interactions between the gut microbiota and its human host in health and in disease. Pivotal studies have demonstrated that manipulation of the gut microbiota and its metabolic pathways can affect host's adiposity and metabolism. These observations have paved the way for further assessment of the mechanisms underlying these changes. In this review we summarize the current evidence for possible mechanisms underlying gut microbiota induced obesity. The review addresses some well-known effects of the gut microbiota on energy harvesting and changes in metabolic machinery, on metabolic and immune interactions and on possible changes in brain function and behavior. Although there is limited understanding on the symbiotic relationship between us and our gut microbiome, and how disturbances of this relationship affects our health, there is compelling evidence for an important role of the gut microbiota in the development and perpetuation of obesity.

Experimental hyperglycemia induces an increase of monocyte and T-lymphocyte content in adipose tissue of healthy obese women

Background/Objectives

Hyperglycemia represents one of possible mediators for activation of immune system and may contribute to worsening of inflammatory state associated with obesity. The aim of our study was to investigate the effect of a short-term hyperglycemia (HG) on the phenotype and relative content of immune cells in circulation and subcutaneous abdominal adipose tissue (SAAT) in obese women without metabolic complications.

Subjects/Methods

Three hour HG clamp with infusion of octreotide and control investigations with infusion of octreotide or saline were performed in three groups of obese women (Group1: HG, Group 2: Octreotide, Group 3: Saline, n=10 per group). Before and at the end of the interventions, samples of SAAT and blood were obtained. The relative content of immune cells in blood and SAAT was determined by flow cytometry. Gene expression analysis of immunity-related markers in SAAT was performed by quantitative real-time PCR.

Results

In blood, no changes in analysed immune cell population were observed in response to HG. In SAAT, HG induced an increase in the content of CD206 negative monocytes/macrophages (p<0.05) and T lymphocytes (both T helper and T cytotoxic lymphocytes, p<0.01). Further, HG promoted an increase of mRNA levels of immune response markers (CCL2, TLR4, TNFα) and lymphocyte markers (CD3g, CD4, CD8a, TBX21, GATA3, FoxP3) in SAAT (p<0.05 and 0.01). Under both control infusions, none of these changes were observed.

Conclusions

Acute HG significantly increased the content of monocytes and lymphocytes in SAAT of healthy obese women. This result suggests that the short-term HG can modulate an immune status of AT in obese subjects.

Association of peripheral total and differential leukocyte counts with obesity-related complications in young adults

OBJECTIVE

Obesity has been demonstrated to be associated with elevated leukocytes in adults and children. This study assessed the associations between peripheral total and differential leukocyte counts and obesity-related complications in young adults.

METHODS

12 obese (median age 21.5 (range 19-28) years, median BMI 35.7 (range 32.0-44.9) kg/m(2)) and 11 normal (median age 23 (range 18-27) years, median BMI 19.5 (range 18.1-21.7) kg/m(2)) adults were enrolled. Complete blood count and serum levels of liver enzymes, fasting blood glucose, insulin and lipids were measured, and the homeostasis model assessment of insulin resistance was calculated. Fat mass was calculated using a bioimpedance analysis device, and ultrasonography was performed to measure fat thickness and to detect fatty change of the liver.

RESULTS

Total leukocyte and monocyte counts were significantly increased in obese young adults. Total leukocyte count was associated with liver enzyme levels, insulin resistance as well as visceral and subcutaneous fat thickness. Neutrophil count was associated with insulin resistance. Lymphocyte count was associated with serum liver enzymes, insulin resistance, and dyslipidemia. Monocyte count was associated with serum liver enzyme, insulin resistance, visceral and subcutaneous fat thickness, body fat mass, and percentage body fat.

CONCLUSION

The results of this study suggest that chronic low-grade systemic inflammation is associated with obesity-related complications such as nonalcoholic fatty liver disease, insulin resistance, and dyslipidemia in young adults.

Increased expression of the interleukin-1 receptor-associated kinase (IRAK)-1 is associated with adipose tissue inflammatory state in obesity

BACKGROUND

The emerging role of TLR2/4 as immuno-metabolic receptors points to key involvement of TLR/IL-1R/MyD88 pathway in obesity/type-2 diabetes (T2D). IL1R-associated kinase (IRAK)-1 is a critical adapter protein (serine/threonine kinase) of this signaling pathway. The changes in adipose tissue expression of IRAK-1 in obesity/T2D remain unclear. We determined modulations in IRAK-1 gene/protein expression in the subcutaneous adipose tissues from lean, overweight and obese individuals with or without T2D.

METHODS

A total of 49 non-diabetic (22 obese, 19 overweight and 8 lean) and 42 T2D (31 obese, 9 overweight and 2 lean) adipose tissue samples were obtained by abdominal subcutaneous fat pad biopsy and IRAK-1 expression was determined using real-time RT-PCR, immunohistochemistry, and confocal microscopy. IRAK-1 mRNA expression was compared with adipose tissue proinflammatory mediators (TNF-α, IL-6, IL-18), macrophage markers (CD68, CD11c, CD163), and plasma markers (CCL-5, C-reactive protein, adiponectin, and triglycerides). The data were analyzed using t test, Pearson's correlation, and multiple stepwise linear regression test.

RESULTS

In non-diabetics, IRAK-1 gene expression was elevated in obese (P = 0.01) and overweight (P = 0.04) as compared with lean individuals and this increase correlated with body mass index (r = 0.45; P = 0.001) and fat percentage (r = 0.36; P = 0.01). In diabetics, IRAK-1 mRNA expression was also higher in obese as compared with lean subjects (P = 0.012). As also shown by immunohistochemistry/confocal microscopy in non-diabetics and by immunohistochemistry in diabetics, IRAK-1 protein expression was higher in obese than overweight and lean adipose tissues. IRAK-1 gene expression correlated positively/significantly with mRNAs of TNF-α (r = 0.46; P = 0.0008), IL-6 (r = 0.30; P = 0.03) and IL-18 (r = 0.31; P = 0.028) in non-diabetics; and only with TNF-α (r = 0.32; P = 0.03) in diabetics. IRAK-1 expression also correlated positively/significantly with CD68 (r = 0.32; P = 0.02), CD11c (r = 0.30; P = 0.03), and CD163 (r = 0.43; P = 0.001) in non-diabetics; and only with CD163 (r = 0.34; P = 0.02) in diabetics. IRAK-1 mRNA levels also correlated with plasma markers including CCL-5 (r = 0.39; P = 0.02), C-reactive protein (r = 0.48; P = 0.005), adiponectin (r = -0.36; P = 0.04), and triglycerides (r = 0.40; P = 0.02) in non-diabetics; and only with triglycerides (r = -0.36; P = 0.04) in diabetics. IRAK-1 expression related with TLR2 (r = 0.39; P = 0.007) and MyD88 (r = 0.36; P = 0.01) in non-diabetics; and MyD88 (r = 0.52; P = 0.0003) in diabetics.

CONCLUSIONS

The elevated IRAK-1 expression in obese adipose tissue showed consensus with local/circulatory inflammatory signatures and represented as a tissue marker for metabolic inflammation. The data have clinical significance as interventions causing IRAK-1 suppression may alleviate meta-inflammation in obesity/T2D.

Evaluation of Toll-Like receptor 2 and 4 RNA expression and the cytokine profile in postmenopausal women with metabolic syndrome

OBJECTIVE

To evaluate the gene expression of Toll-Like (TLR-2 and TLR-4) receptors and cytokine profile in postmenopausal women with or without metabolic syndrome (MetS).

METHODS

In this cross-sectional study, 311 Brazilian women (age≥45 years and amenorrhea≥12 months) were included. Women showing three or more of the following diagnostic criteria were diagnosed as positive for MetS: waist circumference>88 cm, triglycerides≥150 mg/dL, HDL cholesterol<50 mg/dL, blood pressure≥130/85 mmHg, and fasting glucose≥100 mg/dL. The expression of TLR-2 and TLR-4 in peripheral blood was evaluated by RNA extraction and subsequent real time PCR analysis. The cytokine profile, tumor necrosis factor alpha (TNF-α) and interleukins 1β, 6, and 10, were measured by ELISA.

RESULTS

The expression of TLR-2 RNA was demonstrated in 32.5% and TLR-4 in 20.6% of the subjects. There was no association between the expression of TLR-2 and TLR-4 and the presence or absence of MetS (P>0.05). A greater production of IL-6 was associated with TLR-2 and TLR-4 expressions and greater production of TNF-α was associated only with TLR-2 expression (P>0.05). Only the lower quartile of IL-10 was associated with the presence of the MetS (P>0.05).

CONCLUSIONS

TLR-2 and TLR-4 expressions were associated with increased pro-inflammatory cytokines, IL-6 and TNF-α, with no association with biomarkers of MetS. The low concentrations of IL-10 may suggest an anti-inflammatory modulation in postmenopausal women with MetS.

Effect of extracellular vesicles of human adipose tissue on insulin signaling in liver and muscle cells

OBJECTIVE

Insulin resistance (IR) is a key mechanism in obesity-induced cardiovascular disease. To unravel mechanisms whereby human adipose tissue (AT) contributes to systemic IR, the effect of human AT-extracellular vesicles (EVs) on insulin signaling in liver and muscle cells was determined.

METHODS

EVs released from human subcutaneous (SAT) and omental AT (OAT)-explants ex vivo were used for stimulation of hepatocytes and myotubes in vitro. Subsequently, insulin-induced Akt phosphorylation and expression of gluconeogenic genes (G6P, PEPCK) was determined. AT-EV adipokine levels were measured by multiplex immunoassay, and AT-EVs were quantified by high-resolution flow cytometry.

RESULTS

In hepatocytes, AT-EVs from the majority of patients inhibited insulin-induced Akt phosphorylation, while EVs from some patients stimulated insulin-induced Akt phosphorylation. In myotubes AT-EVs exerted an ambiguous effect on insulin signaling. Hepatic Akt phosphorylation related negatively to G6P-expression by both SAT-EVs (r = -0.60, P = 0.01) and OAT-EVs (r = -0.74, P = 0.001). MCP-1, IL-6, and MIF concentrations were higher in OAT-EVs compared to SAT-EVs and differently related to lower Akt phosphorylation in hepatocytes. Finally, the number of OAT-EVs correlated positively with liver enzymes indicative for liver dysfunction.

CONCLUSIONS

Human AT-EVs can stimulate or inhibit insulin signaling in hepatocytes- possibly depending on their adipokine content- and may thereby contribute to systemic IR.

Subnormal peripheral blood leukocyte counts are related to the lowest prevalence and incidence of metabolic syndrome: Tianjin chronic low-grade systemic inflammation and health cohort study

Few studies have assessed the relationship between a subnormal inflammatory status and metabolic syndrome (MS). We therefore designed a cross-sectional and 5-year cohort study to evaluate how a subnormal peripheral blood leukocyte count is related to MS. Participants were recruited from Tianjin Medical University General Hospital-Health Management Centre. Both a baseline cross-sectional (n = 46,179) and a prospective assessment (n = 13,061) were performed. Participants without a history of MS were followed up for 5 years. Leukocyte counts and MS components were assessed at baseline and yearly during the follow-up. Adjusted logistic and Cox proportional hazards regression models were used to assess relationships between the categories of leukocyte counts and MS. The subnormal leukocyte counts group (1,100-3,900 cells/mm(3)) had the lowest prevalence and incidence of MS. The odds ratio and hazard ratio (95% confidence interval) of the highest leukocyte counts were 1.98 (1.57-2.49) and 1.50 (1.22-1.84) (both P for trend <0.0001), respectively, when compared to the subnormal leukocyte counts group after adjusting for potential confounders. This study has shown that subnormal leukocyte counts are independently related to the lowest prevalence and incidence of MS. The findings suggest that it is necessary to restudy and discuss the clinical or preventive value of subnormal leukocyte counts.

Morphological and inflammatory changes in visceral adipose tissue during obesity

Obesity is a major health burden worldwide and is a major factor in the development of insulin resistance and metabolic complications such as type II diabetes. Chronic nutrient excess leads to visceral adipose tissue (VAT) expansion and dysfunction in an active process that involves the adipocytes, their supporting matrix, and immune cell infiltrates. These changes contribute to adipose tissue hypoxia, adipocyte cell stress, and ultimately cell death. Accumulation of lymphocytes, macrophages, and other immune cells around dying adipocytes forms the so-called "crown-like structure", a histological hallmark of VAT in obesity. Cross talk between immune cells in adipose tissue dictates the overall inflammatory response, ultimately leading to the production of pro-inflammatory mediators which directly induce insulin resistance in VAT. In this review, we summarize recent studies demonstrating the dramatic changes that occur in visceral adipose tissue during obesity leading to low-grade chronic inflammation and metabolic disease.

Serum immunoglobulin M concentration is positively related to metabolic syndrome in an adult population: Tianjin Chronic Low-Grade Systemic Inflammation and Health (TCLSIH) Cohort Study

Persistent low-grade systemic inflammation has been increasingly recognized as a common pathological process, and an important contributing factor to cardiovascular diseases and its risk factor, metabolic syndrome. Immunoglobulin M is reactive to multiple autoantigens and is inferred to be important for autoimmunity, implying that immunoglobulin M may be a potential risk factor for metabolic syndrome. However, few epidemiological studies are available which are related to this potential link. Therefore, we designed a cross-sectional study of 9,379 subjects to evaluate the relationship between immunoglobulin M and metabolic syndrome in an adult population. Subjects who received health examinations were recruited from the Tianjin Medical University General Hospital-Health Management Center in Tianjin, China. Immunoglobulin M was determined with an immunonephelometric technique. Metabolic syndrome was defined according to the criteria of the American Heart Association scientific statements of 2009. Multiple logistic regression analysis was used to examine the relationships between the quartiles of immunoglobulin M and the prevalence of metabolic syndrome. After adjustment for covariates, the odds ratio of having metabolic syndrome in the fourth quartile compared with the first quartile of immunoglobulin M was 1.19 times for males (95% confidence interval, 1.002-1.41) and 1.39 times for females (95% confidence interval, 1.07-1.80). Immunoglobulin M levels also showed positive relationships with the ratio of elevated triglycerides and reduced high-density lipoprotein cholesterol in males. The study is the first to show that immunoglobulin M is independently related to metabolic syndrome and its individual components (elevated triglycerides and reduced high-density lipoprotein cholesterol) in males, whereas immunoglobulin M is independently related to metabolic syndrome in females but not to its individual components. Further studies are needed to explore the causality and the exact role of immunoglobulin M in metabolic syndrome.

Obesity indices and inflammatory markers in obese non-diabetic normo- and hypertensive patients: a comparative pilot study

BACKGROUND

The aim of this study was to estimate associations between inflammatory markers and obesity indices in normo- and hypertensive subjects.

METHODS

65 obese adult subjects were divided into two groups: (A) of hypertensives (n = 54) and (B) of normotensives (n = 11). Waist circumference (WC), body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), visceral adiposity index (VAI), body adiposity index (BAI) and tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and high sensitivity C-reactive protein (hsCRP) serum concentrations were estimated.

RESULTS

In group A WHtR was higher (0.69 ± 0.07 vs 0.63 ± 0.06; p < 0.01), hsCRP correlated with BMI and WHtR (r = 0.343; p = 0.011 and r = 0.363; p < 0.01, respectively). BAI correlated with hsCRP in group A and B (r = 0.329; p < 0.05 and r = 0.642; p < 0.05; respectively) and in females and males (r = 0.305; p = 0.05 and r = 0.44; p < 0.05, respectively). In females hsCRP was higher (3.2 ± 2.2 mg/l vs 2.1 ± 1.5 mg/l; p < 0.05). In patients without lipid lowering treatment hsCRP and IL-6 were higher (3.2 ± 1.7 mg/l vs 2.4 ±2.2 mg/l; p = 0.01 and 15.9 ± 7.2 pg/ml vs 13.6 ± 9.9 pg/ml; p < 0.01, respectively).

CONCLUSIONS

WHtR is a sensitive index associated with chronic inflammation in obese hypertensive subjects. BAI correlates with hsCRP independently of hypertension and sex. hsCRP is more sensitive marker associated with obesity than IL-6 and TNF-α. Lipid lowering treatment influence chronic inflammation.

An accelerated mouse model for atherosclerosis and adipose tissue inflammation

Background

Obesity and particularly the metabolic syndrome, which is often associated with obesity, combine a major risk for type 2 diabetes and cardiovascular disease. Emerging evidence indicate obesity-associated subclinical inflammation primarily originating from adipose tissue as a common cause for type 2 diabetes and cardiovascular disease. However, a suitable and well-characterized mouse model to simultaneously study obesity-associated metabolic disorders and atherosclerosis is not available yet. Here we established and characterized a murine model combining diet-induced obesity and associated adipose tissue inflammation and metabolic deteriorations as well as atherosclerosis, hence reflecting the human situation of cardio-metabolic disease.

Methods

We compared a common high-fat diet with 0.15% cholesterol (HFC), and a high-fat, high-sucrose diet with 0.15% cholesterol (HFSC) fed to LDL receptor-deficient (LDLR^-/-) mice. Insulin resistance, glucose tolerance, atherosclerotic lesion formation, hepatic lipid accumulation, and inflammatory gene expression in adipose tissue and liver were assessed.

Results

After 12–16 weeks, LDLR^-/- mice fed HFSC or HFC developed significant diet-induced obesity, adipose tissue inflammation, insulin resistance, and impaired glucose tolerance compared to lean controls. Notably, HFSC-fed mice developed significantly higher adipose tissue inflammation in parallel with significantly elevated atherosclerotic lesion area compared to those on HFC. Moreover, LDLR^-/- mice on HFSC showed increased insulin resistance and impaired glucose tolerance relative to those on HFC. After prolonged feeding (20 weeks), however, no significant differences in inflammatory and metabolic parameters as well as atherosclerotic lesion formation were detectable any more between LDLR^-/- mice fed HFSC or HFC.

Conclusion

The use of high sucrose rather than more complex carbohydrates in high-fat diets significantly accelerates development of obesity-driven metabolic complications and atherosclerotic plaque formation parallel to obesity-induced adipose tissue inflammation in LDLR^-/- mice. Hence LDLR^-/- mice fed high-fat high-sucrose cholesterol-enriched diet appear to be a suitable and time-saving animal model for cardio-metabolic disease. Moreover our results support the suggested interrelation between adipose tissue inflammation and atherosclerotic plaque formation.

Dynamic interplay between metabolic syndrome and immunity

Obesity and its co-morbidities as metabolic syndrome, type 2 diabetes mellitus and cardiovascular diseases are major health problems worldwide. Several reports indicated that nutrient excess and metabolic syndrome are linked with altered immune response. Indeed, metabolic syndrome is characterized by insulin resistance and chronic low-grade inflammation, which conditions are the consequences of the complex interaction between adipocytes and immune cells. Enlarged white adipose tissue is infiltrated by immune cells and secretes various bioactive substances, like adipokines, cytokines and other inflammatory mediators. Due to its special architecture in which metabolic and immune cells are in intimate proximity, metabolic and immunologic pathways are closely integrated in adipose tissue. With the contribution of altered gut microbiota, adipokines and cytokines modulate insulin signaling and immune response leading to adipose tissue inflammation and systemic insulin resistance. In this chapter, we focus on the cellular and molecular mechanisms that lead to impaired insulin sensitivity and chronic low-grade inflammation in obesity. We also detail the potential role of adipokines and immune cells in this deleterious process, and the concerns of vaccination in metabolic syndrome. Finally, we address the links between obesity and gut microbiota as an emerging new field of interest, and scratch the surface of potential therapeutic opportunities.

Modulation of adipose tissue inflammation by FOXP3+ Treg cells, IL-10, and TGF-β in metabolically healthy class III obese individuals

OBJECTIVE

The objective of this study was to compare the profiles of proinflammatory (interleukin [IL]-6 and tumor necrosis factor [TNF]) and anti-inflammatory (IL-10 and transforming growth factor [TGF]-β) adipokines in the blood, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) of metabolically healthy class III obese individuals and normal-weight controls.

METHODS

The serum concentrations (enzyme-linked immunosorbent assay [ELISA]), mRNA expression levels (reverse transcriptase polymerase chain reaction), and adipose tissue secretion (ELISA) of IL-6, TNF, IL-10, and TGF-β were analyzed, as were the mRNA expression of FOXP3 (present in regulatory T cells) and the secretion (Western blotting) of matrix metalloproteinases in the adipose tissue.

RESULTS

There were no differences in the circulating levels, expression, or secretion of IL-6 and TNF between the groups or tissues. The expression and circulating levels of IL-10 were higher in obese individuals, especially in the SAT. Although the blood concentration of TGF-β was similar between the groups, its expression and secretion levels were higher in the adipose tissues of obese individuals compared with controls. FOXP3 and MMP expression levels were higher in the SAT and VAT of obese individuals, respectively, compared with the controls.

CONCLUSION

Metabolically healthy, extremely obese individuals have effective immunoregulation to counter chronic obesity-related inflammation through the increased production of the anti-inflammatory cytokines IL-10 and TGF-β in adipose tissue, especially SAT; the increased presence of FOXP3-positive regulatory T cells; and increases in angiogenesis and adipogenesis induced by TGF-β and MMPs. These regulatory mechanisms could be important in the delayed onset of metabolic complications, even in extremely obese individuals.

Adipose tissue immunity and cancer

Inflammation and altered immune response are important components of obesity and contribute greatly to the promotion of obesity-related metabolic complications, especially cancer development. Adipose tissue expansion is associated with increased infiltration of various types of immune cells from both the innate and adaptive immune systems. Thus, adipocytes and infiltrating immune cells secrete pro-inflammatory adipokines and cytokines providing a microenvironment favorable for tumor growth. Accumulation of B and T cells in adipose tissue precedes macrophage infiltration causing a chronic low-grade inflammation. Phenotypic switching toward M1 macrophages and Th1 T cells constitutes an important mechanism described in the obese state correlating with increased tumor growth risk. Other possible synergic mechanisms causing a dysfunctional adipose tissue include fatty acid-induced inflammation, oxidative stress, endoplasmic reticulum stress, and hypoxia. Recent investigations have started to unravel the intricacy of the cross-talk between tumor cell/immune cell/adipocyte. In this sense, future therapies should take into account the combination of anti-inflammatory approaches that target the tumor microenvironment with more sophisticated and selective anti-tumoral drugs.

Inflammation triggers high mobility group box 1 (HMGB1) secretion in adipose tissue, a potential link to obesity

BACKGROUND

Low grade inflammation is one of the major metabolic disorders in case of obesity due to variable secretion of adipose derived cytokines called adipokines. Recently the nuclear protein HMGB1 was identified as an inflammatory alarmin in obesity associated diseases. However HMGB1 role in adipose tissue inflammation is not yet studied.

OBJECTIVES

The aim of this study was to prove the expression of HMGB1 in human adipose tissue and to assess the levels of expression between normo-weight and obese individuals. Furthermore we determined which type of cells within adipose tissue is involved in HMGB1 production under inflammatory signal.

METHODS

Western-blot was performed on protein lysates from human normo-weight and obese adipose tissue to study the differential HMGB1 expression. Human normo-weight adipose tissue, adipose-derived stromal cells (ASCs) and adipocytes were cultured and stimulated with LPS to induce inflammation. HMGB1, IL-6 and MCP-1 secretion and gene expression were quantified by ELISA and Q-PCR respectively, as well as cell death by LDH assay. HMGB1 translocation during inflammation was tracked down by immunofluorescence in ASCs.

RESULTS

HMGB1 was expressed 2-fold more in adipose tissue from obese compared to normo-weight individuals. LPS led to an up-regulation in HMGB1 secretion and gene expression in ASCs, while no change was noticed in adipocytes. Moreover, this HMGB1 release was not attributable to any cell death. In LPS-stimulated ASCs, HMGB1 translocation from nucleus to cytoplasm was detectable at 12h and the nuclear HMGB1 was completely drained out after 24h of treatment.

CONCLUSION

The expression level studies between adipose tissue from normo-weight and obese individuals together with in vitro results strongly suggest that adipose tissue secretes HMGB1 in response to inflammatory signals which characterized obesity.

VEGF in the crosstalk between human adipocytes and smooth muscle cells: depot-specific release from visceral and perivascular adipose tissue

Adipose tissue secrets adipokines and fatty acids, which may contribute to obesity-associated vascular dysfunction and cardiovascular risk. This study investigated which factors are responsible for the synergistic effect of adipokine and oleic acid- (OA-) induced proliferation of human vascular smooth muscle cells (VSMC). Adipocyte-conditioned medium (CM) from human adipocytes induces proliferation of VSMC in correlation to its vascular endothelial growth factor (VEGF) content. CM increases VEGF-receptor (VEGF-R) 1 and 2 expression and VEGF secretion of VSMC, while OA only stimulates VEGF secretion. VEGF neutralization abrogates CM- and OA-induced proliferation and considerably reduces proliferation induced by CM and OA in combination. VEGF release is higher from visceral adipose tissue (VAT) of obese subjects compared to subcutaneous adipose tissue (SAT) and VAT from lean controls. Furthermore, VEGF release from VAT correlates with its proliferative effect. Perivascular adipose tissue (PAT) from type 2 diabetic patients releases significantly higher amounts of VEGF and induces stronger proliferation of VSMC as compared to SAT and SAT/PAT of nondiabetics. In conclusion, VEGF is mediating CM-induced proliferation of VSMC. As this adipokine is released in high amounts from VAT of obese patients and PAT of diabetic patients, VEGF might link adipose tissue inflammation to increased VSMC proliferation.

The cat as a model for human obesity: insights into depot-specific inflammation associated with feline obesity

According to human research, the location of fat accumulation seems to play an important role in the induction of obesity-related inflammatory complications. To evaluate whether an inflammatory response to obesity depends on adipose tissue location, adipokine gene expression, presence of immune cells and adipocyte cell size of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were compared between lean and obese cats. Additionally, the present study proposes the cat as a model for human obesity and highlights the importance of animal models for human research. A total of ten chronically obese and ten lean control cats were included in the present study. Body weight, body condition score and body composition were determined. T-lymphocyte, B-lymphocyte, macrophage concentrations and adipocyte cell size were measured in adipose tissue at different locations. Serum leptin concentration and the mRNA expression of leptin and adiponectin, monocyte chemoattractant protein-1, chemoligand-5, IL-8, TNF-α, interferon-γ, IL-6 and IL-10 were measured in blood and adipose tissues (abdominal and inguinal SAT, and omental, bladder and renal VAT). Feline obesity was characterised by increased adipocyte cell size and altered adipokine gene expression, in favour of pro-inflammatory cytokines and chemokines. Consequently, concentration of T-lymphocytes was increased in the adipose tissue of obese cats. Alteration of adipose tissue was location dependent in both lean and obese cats. Moreover, the observed changes were more prominent in SAT compared with VAT.

Body mass index and musculoskeletal pain: is there a connection?

Background

Back pain is one of the most common complaints that patients report to physicians and two-thirds of the population has an elevated body mass index (BMI), indicating they are either overweight or obese. It was once assumed that extra body weight would stress the low back and lead to pain, however, researchers have reported inconsistencies association between body weight and back pain. In contrast, more recent studies do indicate that an elevated BMI is associated with back pain and other musculoskeletal pain syndromes due to the presence of a chronic systemic inflammatory state, suggesting that the relationship between BMI and musculoskeletal pains be considered in more detail.

Objective

To describe how an elevated BMI can be associated with chronic systemic inflammation and pain expression. To outline measurable risk factors for chronic inflammation that can be used in clinical practice and discuss basic treatment considerations.

Discussion

Adiposopathy, or “sick fat” syndrome, is a term that refers to an elevated BMI that is associated with a chronic systemic inflammatory state most commonly referred to as the metabolic syndrome. The best available evidence suggests that the presence of adiposopathy determines if an elevated BMI will contribute to musculoskeletal pain expression. It is not uncommon for physicians to fail to identify the presence of adiposopathy/metabolic syndrome.

Conclusion

Patients with an elevated BMI should be further examined to identify inflammatory factors associated with adiposopathy, such as the metabolic syndrome, which may be promoting back pain and other musculoskeletal pain syndromes.

Deficiency of C5L2 increases macrophage infiltration and alters adipose tissue function in mice

Background

Obesity is considered as a systemic chronic low grade inflammation characterized by increased serum pro-inflammatory proteins and accumulation of macrophages within white adipose tissue (WAT) of obese patients. C5L2, a 7-transmembrane receptor, serves a dual function, binding the lipogenic hormone acylation stimulating protein (ASP), and C5a, involved in innate immunity.

Aim

We evaluated the impact of C5L2 on macrophage infiltration in WAT of wildtype (Ctl) and C5L2 knock-out (C5L2^−/−) mice over 6, 12 and 24 weeks on a chow diet and moderate diet-induced obesity (DIO) conditions.

Results

In Ctl mice, WAT C5L2 and C5a receptor mRNA increased (up to 10-fold) both over time and with DIO. By contrast, in C5L2^−/−, there was no change in C5aR in WAT. C5L2^−/− mice displayed higher macrophage content in WAT, varying by time, fat depot and diet, associated with altered systemic and WAT cytokine patterns compared to Ctl mice. However, in all cases, the M1 (pro-) vs M2 (anti-inflammatory) macrophage proportion was unchanged but C5L2^−/− adipose tissue secretome appeared to be more chemoattractant. Moreover, C5L2^−/− mice have increased food intake, increased WAT, and altered WAT lipid gene expression, which is reflected systemically. Furthermore, C5L2^−/− mice have altered glucose/insulin metabolism, adiponectin and insulin signalling gene expression in WAT, which could contribute to development of insulin resistance.

Conclusion

Disruption of C5L2 increases macrophage presence in WAT, contributing to obesity-associated pathologies, and further supports a dual role of complement in WAT. Understanding this effect of the complement system pathway could contribute to targeting treatment of obesity and its comorbidities.

DPP-4 Inhibitors as Therapeutic Modulators of Immune Cell Function and Associated Cardiovascular and Renal Insulin Resistance in Obesity and Diabetes

The prevalence of obesity and diabetes continues to rise in the United States and worldwide. These findings parallel the expansion of childhood obesity and diabetes. Obesity is a central component of the cardiorenal metabolic syndrome (CRS) which increases the risk for cardiovascular disease (CVD) and chronic kidney disease (CKD). The hallmark of obesity, CRS, and early type 2 diabetes is insulin resistance, a result of decreased insulin metabolic signaling due, in part, to enhanced serine phosphorylation and/or proteasome-mediated degradation of the insulin receptor substrate. Cardiovascular and renal insulin resistance significantly contributes to endothelial dysfunction, impaired cardiac diastolic and vascular relaxation, glomerular injury, and tubular dysfunction. In this context, multiple factors including oxidative stress, increased inflammation, and inappropriate activation of the renin-angiotensin-aldosterone and the sympathetic nervous system contribute to overweight- and obesity-induced systemic and tissue insulin resistance. One common link between obesity and the development of insulin resistance appears to be a low-grade inflammatory response resulting from dysfunctional innate and adaptive immunity. In this regard, there has been recent work on the role of dipeptidyl peptidase-4 (DPP-4) in modulating innate and adaptive immunity. The direct effects of DPP-4 on immune cells and the indirect effects through GLP-1-dependent and -independent pathways suggest effects of DPP-4 inhibition may have beneficial effects beyond glycemic control in improving CVD and renal outcomes. Accordingly, this review addresses new insights into the role of DPP-4 in immune modulation and the potential beneficial effects of DPP-4 inhibitors in insulin resistance and associated CVD and CKD prevention.

Body mass index, obesity, and prevalent gout in the United States in 1988-1994 and 2007-2010

OBJECTIVE

To determine the association and prevalence of gout among overweight, obese, and morbidly obese segments of the US population.

METHODS

Among participants (age ≥20 years) of the National Health and Nutrition Examination Surveys in 1988-1994 and 2007-2010, gout status was ascertained by self-report of a physician diagnosis. Body mass index (BMI) was examined in categories of <18.5 kg/m(2) , 18.5-24.9 kg/m(2) , 25-29.9 kg/m(2) , 30-34.9 kg/m(2) , and ≥35 kg/m(2) and as a continuous variable. The cross-sectional association of BMI category with gout status was adjusted for demographic and obesity-related medical disorders.

RESULTS

In the US, the crude prevalence of gout was 1-2% among participants with a normal BMI (18.5-24.9 kg/m(2) ), 3% among overweight participants, 4-5% with class I obesity, and 5-7% with class II or class III obesity. The adjusted prevalence ratio comparing the highest to a normal BMI category was 2.46 (95% confidence interval [95% CI] 1.44-4.21) in 1988-1994 and 2.21 (95% CI 1.50-3.26) in 2007-2010. Notably, there was a progressively greater prevalence ratio of gout associated with successively higher categories of BMI. In both survey periods, for an average American adult standing 1.76 meters (5 feet 9 inches), a 1-unit higher BMI, corresponding to 3.1 kg (~6.8 pounds) greater weight, was associated with a 5% greater prevalence of gout, even after adjusting for serum uric acid (P < 0.001).

CONCLUSION

Health care providers should be aware of the elevated burden of gout among both overweight and obese adults, applicable to both women and men, and observed among non-Hispanic whites, non-Hispanic African Americans, and Mexican Americans in the US.

n-3 fatty acids modulate adipose tissue inflammation and oxidative stress

PURPOSE OF REVIEW

Dietary n-3 polyunsaturated fatty acids (n-3 PUFAs) may be related to a number of chronic metabolic abnormalities, including metabolic syndrome. This review presents an update on the effects of n-3 PUFAs on risk factors of metabolic syndrome, especially adipose tissue inflammation, oxidative stress and underlying mechanisms of these effects.

RECENT FINDINGS

Anti-inflammatory actions of n-3 PUFAs are thought to be mediated by the formation of their active metabolites (eicosanoids and other lipid mediators) as well as their regulation of the production of inflammatory mediators (e.g., adipocytokines, cytokines) and immune cell infiltration into adipose tissue. n-3 PUFAs mediate these effects by modulating several pathways, such as those involving nuclear factor-κB, peroxisome proliferator-activated receptors and Toll-like receptors. The antioxidative effects of n-3 PUFAs in adipocytes appear to inhibit reactive oxygen species production and alter mitochondrial function.

SUMMARY

This review summarizes the evidence for beneficial effects of n-3 PUFAs on adipose tissue inflammation and oxidative stress. More studies are necessary to investigate the mechanisms underlying these effects and to relate this topic to human health.