Role of adipokines in complications related to obesity: a review

The expression of LEP, LEPR, IGF1 and IL10 in obesity and the relationship with microRNAs

Obesity is a multifactorial disease, with epigenetic alterations. Have been described modifications in the expression of some microRNAs, and some proteins related to obesity. The objective was to determine and correlate, in obese patients, the gene expression of LEP, LEPR, IGF1, IL10 and of miR-27a, miR-27b, miR-143 and miR-145. RNA was extracted from biopsies of subcutaneous fat, liver and visceral fat of 15 obese subjects submitted to bariatric surgery and of 15 non-obese subjects submitted to cholecystectomy for cDNA synthesis and for RT-PCR. The microRNAs were chosen using the TargetScan software. An increased expression of LEP and IGF1 was detected in the subcutaneous fat of the obese group compared to control, while the expression of IGF1 was higher in the control group than in the obese one. MiRNA-27a had a higher expression in the omentum of the obese patients and there was also a correlation in the expression of miRNA-145 and LEPR in the omentum of this group.

Clinicopathological roles of adiponectin and leptin receptors in endometrial carcinoma

To clarify the roles of adiponectin receptor (AdipoR) and leptin receptor (ObR) in endometrial carcinoma, the expression of AdipoR-1 and -2 and ObR in endometrial cancer was examined immunohistochemically, and correlations with clinicopathological implications were also analysed. Paraffin-embedded tissues were obtained from 77 patients with endometrial carcinoma and were stained immunohistochemically using antibodies against AdipoR-1, AdipoR-2 and ObR. AdipoR-1, AdipoR-2 and ObR were localised predominantly in the cell membrane and cytoplasm of tumour cells and normal endometrial cells. In 77 cases of endometrial cancer, positive expression was observed in 46 cases (59.7%) for AdipoR-1, 47 cases (61.0%) for AdipoR-2 and 33 cases (42.9%) for ObR. Expression of AdipoR-1 was observed most in stage I cases, G1 tumours, tumours with shallow myometrial invasion, tumours negative for lymphovascular space involvement, cases negative for adnexal invasion and cases with no lymph node metastasis. However, the expression of AdipoR-2 and ObR showed no correlation with any clinicopathological factors. Kaplan-Meier analyses revealed that progression-free and overall survival times were longer in cases with positive AdipoR-1 expression compared with negative AdipoR-1 expression. Poor expression of AdipoR-1, thus, appears to be associated with tumour grade, myometrial invasion, adnexal invasion, lymph-vascular space involvement and lymph node metastasis, as well as poor prognosis, in endometrial cancer.

The influence of obesity on inflammation and clinical symptoms in asthma

Obesity and asthma are both important public health issues. Increasing number of studies suggest the association between obesity and asthma which may be causal or accidental. The studies on animal models show innate enhancement of airway hyper-responsiveness which suggest that chronic airway hyper-responsiveness may be related to chronic low-grade systemic inflammation occurring in obesity. These results are confirmed by studies on asthmatic patients which show that levels of inflammation markers were higher in obese asthma patients and are related to the parameters of obesity. However, adipokines secreted by adipose tissue have also been involved in the regulation of inflammation and allergic responses, and suggested to affect the risk of asthma, especially in obese female patients. The studies on the association between adiposity and atopy have conflicting results and the issue needs to be investigated in the future. Obesity also decreases lung volume and increases airway resistance inducing symptoms that could mimic asthma. Clinical studies suggest that asthma in obese subjects may differ from the classical phenotype of the disease. Obese patients referred for asthma exacerbation present a reduced response to standard asthma medications. The review indicates that mechanical and inflammatory effects of obesity may explain the influence on asthma. Further studies on the association between adiposity and atopy on airway inflammation may confirm the active role of fat tissue, not only simple mechanical impairment of the thorax movement. Longitudinal studies are needed to understand the association between asthma, and obesity, which may open new therapeutic options for asthma treatment in obese patients.

Management of reproduction and pregnancy complications in maternal obesity: which role for dietary polyphenols?

Obesity is a global and dramatic public health problem; maternal obesity represents one of the main risk factors of infertility and pregnancy complications as it is associated with adverse maternal and offspring outcomes. In the last few years, adipose tissue dysfunction associated with altered adipocytokine secretion has been suggested to play a critical role in all the phases of reproductive process. Obesity is a nutrition-related disorder. In this regard, dietary intervention strategies, such as high intake of fruit and vegetables, have shown significant effects in both preserving health and counteracting obesity-associated diseases. Evidence has been provided that polyphenols, important constituents of plant-derived food, can influence developmental program of oocyte and embryo, as well as pregnancy progression by modulating several cellular pathways. This review will examine the controversial results so far obtained on adipocytokine involvement in fertility impairment and pregnancy complications. Furthermore, the different effects exerted by polyphenols on oocyte, embryo, and pregnancy development will be also taken in account.

Body composition and body fat distribution are related to cardiac autonomic control in non-alcoholic fatty liver disease patients

BACKGROUND/OBJECTIVES

Heart rate recovery (HRR), a cardiac autonomic control marker, was shown to be related to body composition (BC), yet this was not tested in non-alcoholic fatty liver disease (NAFLD) patients. The aim of this study was to determine if, and to what extent, markers of BC and body fat (BF) distribution are related to cardiac autonomic control in NAFLD patients.

SUBJECTS/METHODS

BC was assessed with dual-energy X-ray absorptiometry in 28 NAFLD patients (19 men, 51±13 years, and 9 women, 47±13 years). BF depots ratios were calculated to assess BF distribution. Subjects' HRR was recorded 1 (HRR1) and 2 min (HRR2) immediately after a maximum graded exercise test.

RESULTS

BC and BF distribution were related to HRR; particularly weight, trunk BF and trunk BF-to-appendicular BF ratio showed a negative relation with HRR1 (r=-0.613, r=-0.597 and r=-0.547, respectively, P<0.01) and HRR2 (r=-0.484, r=-0.446, P<0.05, and r=-0.590, P<0.01, respectively). Age seems to be related to both HRR1 and HRR2 except when controlled for BF distribution. The preferred model in multiple regression should include trunk BF-to-appendicular BF ratio and BF to predict HRR1 (r2=0.549; P<0.05), and trunk BF-to-appendicular BF ratio alone to predict HRR2 (r2=0.430; P<0.001).

CONCLUSIONS

BC and BF distribution were related to HRR in NAFLD patients. Trunk BF-to-appendicular BF ratio was the best independent predictor of HRR and therefore may be best related to cardiovascular increased risk, and possibly act as a mediator in age-related cardiac autonomic control variation.

Onion peel tea ameliorates obesity and affects blood parameters in a mouse model of high-fat-diet-induced obesity

The present study examined the effects of onion peel tea (OPT) in a mouse model of high-fat-diet-induced obesity. BALB/c mice were fed a high-fat diet for three weeks, followed by a normal diet with or without OPT for 28 days. OPT suppressed the increases in body weight and level of epididymal fat tissue; it also significantly reduced the serum concentrations of total cholesterol on day 14 and those of glucose and leptin on day 28. The results indicate that OPT has anti-obesity effects in an experimental mouse model of high-fat-diet-induced obesity.

Serum leptin, adiponectin and endometrial cancer risk in Chinese women

Objective

To investigate the relationship between serum concentrations of leptin or adiponectin, and endometrial carcinoma in Chinese women.

Methods

We conducted a case-control study of a total of 516 Chinese women to detect the relationships between serum concentrations of leptin or adiponectin, and endometrial carcinoma in Chinese women. The study subject constituted 206 cases of endometrial cancer and 310 normal controls.

Results

Patients with endometrial carcinoma had higher serum leptin concentrations than controls (28.8±2.2 ug/L vs. 19.8±1.4 ug/L; p<0.001). The adiponectin levels in patients were lower than in controls with borderline statistical significance (2,330.7±180.5 ug/L vs. 2,583.9±147.2 ug/L; p=0.078). Logistic regression analysis confirmed the associations between leptin or adiponectin, and endometrial carcinoma after adjustment for age, body mass index, fasting insulin, serum glucose, cholesterol, triglycerides, and high-density lipoprotein cholesterol (odds ratio for the top tertile vs. the bottom tertile: leptin 2.05; 95% confidence interval [CI], 1.28 to 3.29; p<0.001; adiponectin 0.52; 95% CI, 0.32 to 0.83; p<0.001).

Conclusion

Increased leptin or decreased adiponectin levels are associated with endometrial carcinoma.

Metabolic syndrome in the offspring of centenarians: focus on prevalence, components, and adipokines

With aging, an increased prevalence of a clustering of metabolic abnormalities has been observed. These abnormalities include obesity, dyslipidemia, hypertension, and insulin resistance and are collectively known as metabolic syndrome (MetS), a low-grade, systemic, inflammatory condition associated with an increased risk of cardiovascular disease, diabetes, and other adverse health outcomes. A number of studies have demonstrated that centenarians' offspring have a significant survival advantage and a lower risk of developing the most important age-related diseases. They therefore represent one of the best models with which to study the familiar component of human longevity. The aim of this study was to determine if the offspring of centenarians (n = 265 subjects) showed a different prevalence of MetS in comparison to the offspring of non-long-lived parents (controls, n = 101 subjects). In addition, we assessed whether centenarians' offspring showed particular features of MetS and a distinct regulation of circulating adipokines, cytokines, and metabolic mediators. Although the prevalence of MetS was quite similar both in the offspring of centenarians and the controls, MetS-affected centenarians' offspring seemed healthier, more functionally fit, and had lower resistin levels. MetS prevalence did not change in centenarians' offspring across resistin, IGF-1, and resistin/IGF-1 ratio tertiles. On the other hand, in controls, MetS prevalence strongly increased across resistin tertiles and in the third resistin/IGF-1 ratio tertile, indicating a dramatic increase in MetS prevalence when the ratio between these two factors is unbalanced, with high levels of resistin and low levels of IGF-1.

Oxidative Stress and Low-Grade Inflammatory Status as Cardiometabolic Risk Factors in Italian Occupational Overweight/Obese Subjects

Obesity is associated with increased risk of cardiometabolic diseases. Adipocytokines (e.g. leptin), produced by the endocrine function of adipose tissue, can contribute to cardiometabolic risk in overweight and obese people. Oxidative stress, imbalance between oxidants and antioxidants, is considered a cardiovascular risk factor. High serum oxidized LDL (oxLDL) levels, marker of lipid peroxidation, a primary cause of atherosclerosis, can contribute to its progression. The aims of this study are to assess markers of oxidative status and cytokine profile and evaluate their role as cardiometabolic risk factors and possible correlations. In this cross-sectional study, we enrolled 76 occupational overweight-obese adults (46 females, 30 males; aged 46.8±9.5; BMI 33.7±4.8 kg/m2) without any previous cardiovascular disease. Oxidative status was measured by evaluating serum Reactive Oxygen Species (ROS) levels, Total Antioxidant Capacity (TAC) and oxLDL concentrations. All subjects' soluble cytokine and adhesion molecule levels were evaluated by cytofluorimetric method and compared with 35 controls matched for sex and age. ROS and oxLDL levels were high in 84% and 92% of the study population, respectively, despite adequate TAC (68%). Female ROS levels were significantly higher than those of males (414±99.3 vs 318±48.2 UCarr, p<0.0001), while their oxLDL levels were lower (95.3±22 vs 105.2±19.4 U/L, p=0.1). Leptin and sICAM-1 (intracellular adhesion molecule involved in leukocyte migration to inflamed area) levels of the study population were significantly higher than those of controls (93.8±89.1 vs 25.3±23 ng/mL, p=0.0002 and 505.8±236.7 vs 339.2±119.6 ng/mL, p=0.0009, respectively). Overweight/obese occupational subjects showed oxidative stress conditions accompanied by low chronic inflammatory status, possibly contributing to increased cardiometabolic risk.

The association of adiponectin with computed tomography phenotypes in chronic obstructive pulmonary disease

RATIONALE

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder associated with systemic manifestations that contribute to its morbidity and mortality. Recent work suggests that biomarker signatures in the blood may be useful in evaluating COPD phenotypes and may provide insight into the pathophysiology of systemic manifestations. Adiponectin, primarily produced by fat cells, has been implicated in the pathophysiology of emphysema.

OBJECTIVES

To investigate the association of adiponectin with clinical and radiologic COPD phenotypes.

METHODS

Adiponectin levels were determined in 633 individuals, including 432 individuals with COPD from a cohort of former or current smokers enrolled in the COPDGene study. Univariate and multiple regression analysis were used to examine the association of adiponectin with clinical and physiologic data together with quantitative high-resolution computed tomography parameters.

MEASUREMENTS AND MAIN RESULTS

Multiple regression analysis confirmed that higher plasma adiponectin levels were independently associated with emphysema, decreasing body mass index, female sex, older age, and lower percentage change in prebronchodilator/post-bronchodilator FEV1.

CONCLUSIONS

The association between plasma adiponectin and computed tomography-assessed emphysema suggests a contribution of adiponectin to the development of emphysema and highlights a role for metabolic derangements in the pathophysiology of emphysema.

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.

Dietary fat differentially influences the lipids storage on the adipose tissue in metabolic syndrome patients

PURPOSE

Adipose tissue is now recognized as a highly active metabolic and endocrine organ. Our aim was to investigate the effect of the dietary fat on the two main adipose tissue functions, endocrine and lipid store, by analyzing the adipose tissue gene expression from metabolic syndrome patients.

METHODS

A randomized, controlled trial conducted within the LIPGENE study assigned 39 metabolic syndrome patients to 1 of 4 isoenergetic diets: (1) high-saturated fatty acid (HSFA), (2) high-monounsaturated fatty acid (HMUFA), (3) low-fat, high-complex carbohydrate diet supplemented with long-chain n-3 fatty acids (LFHCC n-3), and (4) low-fat, high-complex carbohydrate diet supplemented with placebo (LFHCC), for 12 weeks each. A fat challenge reflecting the fatty acid composition as the original diets was conducted post-intervention.

RESULTS

The long-term consumption of HSFA, LFHCC, and LFHCC n-3 diets, but not HMUFA diet, decreased the perilipin fasting mRNA levels. LFHCC diet consumption increased fasting FABP4 expression, while it was reduced by the consumption of LFHCC n-3 diet. LFHCC meal reduced, while LFHCC n-3 meal intake increased postprandial CAV1 expression.

CONCLUSION

The quantity and quality of dietary fat induce differential lipid storage and processing related gene expression, which may interact with the expression of adipokines through common regulatory mechanisms.

Injection of phosphatidylcholine and deoxycholic acid regulates gene expression of lipolysis-related factors, pro-inflammatory cytokines, and hormones on mouse fat tissue

Injection of phosphatidylcholine (PC) and deoxycholic acid (DA) preparation is widely used as an alternative to liposuction for the reduction of subcutaneous fat. Nevertheless, its physiological effects and mechanism of action are not yet fully understood. In this report, PC and deoxycholic acid (DA) were respectively injected into adipose tissue. PC decreased tissue mass on day 7, but DA did not. On the other hand, a decrement of DNA mass was observed only in DA-injected tissue on day 7. Both PC and DA reduced the mRNA expression of adipose tissue hormones, such as adiponectin, leptin, and resistin. In lipolysis-related gene expression profiles, PC increased hormone-sensitive lipase (HSL) transcription and decreased the expression other lipases, perilipin, and the lipogenic marker peroxisome proliferator-activated receptor-γ (PPARγ); DA treatment diminished them all, including HSL. Meanwhile, the gene expression of pro-inflammatory cytokines and a chemokine was greatly elevated in both PC-injected and DA-injected adipose tissue. Microscopic observation showed that PC induced lipolysis with mild PMN infiltration on day 7. However, DA treatment did not induce lipolysis but induced much amount of PMN infiltration. In conclusion, PC alone might induce lipolysis in adipose tissue, whereas DC alone might induce tissue damage.

Effect of obesity on the acute inflammatory response in pregnant and cycling female rats

Nonpregnant female rats have a lower inflammatory response to lipopolysaccharide (LPS) than males and, at late stages of gestation, the fever response to this immunogen is almost completely suppressed. We have shown in males that obesity exacerbates sickness responses to pathogenic stimuli. In the present study, we investigated whether obesity would have a similar effect in females and reverse some of the suppressive effects of pregnancy on the innate immune response. Lean and diet-induced obese adult Wistar rats were randomly separated into either cycling or mated groups. On day 18 of pregnancy or in the metestrous/dioestrous phase in cycling rats, a single injection of LPS (100 μg/kg) was administered and rats were sacrificed 8h or 24 h later. In pregnant females, LPS induced a higher increase in body temperature in obese rats only at the 24-h time point and lower hypothalamic interleukin (IL)-1β expression and higher circulating levels of IL-1 receptor antagonist (ra) than their cycling counterparts. Conversely, there was no suppression of inflammatory signals in the white adipose tissue of pregnant rats. At 24 h post LPS, the cell surface marker CD11c and IL-6 mRNA expression were increased in white adipose tissue from obese rats regardless of reproductive state, whereas IL-1ra was highest in the LPS-treated obese pregnant group. In cycling females, LPS induced a higher fever response in obese rats accompanied by higher circulating levels of IL-6 and IL-1ra, as well as an increase in circulating leptin only in the obese cycling group. In the hypothalamus, obese rats showed significantly higher expression of nuclear factor-IL-6 in at the 8-h time point. Collectively, these results show that diet-induced obesity in females is associated with a similar pattern of response to that previously observed in males. On the other hand, obesity had limited effects in pregnant rats, with the exception of white adipose tissue.

Nuclear receptor corepressor (NCOR1) regulates in vivo actions of a mutated thyroid hormone receptor α

Genetic evidence from patients with mutations of the thyroid hormone receptor α gene (THRA) indicates that the dominant negative activity of mutants underlies the pathological manifestations. However, the molecular mechanisms by which TRα1 mutants exert dominant negative activity in vivo are not clear. We tested the hypothesis that the severe hypothyroidism in patients with THRA mutations is due to an inability of TRα1 mutants to properly release the nuclear corepressors (NCORs), thereby inhibiting thyroid hormone-mediated transcription activity. We crossed Thra1(PV) mice, expressing a dominant negative TRα1 mutant (TRα1PV), with mice expressing a mutant Ncor1 allele (Ncor1(ΔID) mice) that cannot recruit the TR or PV mutant. TRα1PV shares the same C-terminal mutated sequences as those of patients with frameshift mutations of the THRA gene. Remarkably, NCOR1ΔID ameliorated abnormalities in the thyroid-pituitary axis of Thra1(PV/+) mice. The severe retarded growth, infertility, and delayed bone development were partially reverted in Thra1(PV/+) mice expressing NCOR1ΔID. The impaired adipogenesis was partially corrected by de-repression of peroxisome-proliferator activated receptor γ and CCAAT/enhancer-binding protein α gene, due to the inability of TRα1PV to recruit NCOR1ΔID to form a repressor complex. Thus, the aberrant recruitment of NCOR1 by TRα1 mutants could lead to clinical hypothyroidism in humans. Therefore, therapies aimed at the TRα1-NCOR1 interaction or its downstream actions could be tested as potential targets in treating TRα1 mutant-mediated hypothyroidism in patients.

Human subcutaneous adipose tissue Glut 4 mRNA expression in obesity and type 2 diabetes

Cellular resistance to insulin caused by reduced glucose transport and metabolism is a primary defect leading to the development of metabolic disease. While the etiology of insulin resistance is multifactorial, reduced insulin action is associated with impaired activity of the glucose transporter GLUT4 in insulin-sensitive tissues. Yet, the role of adipose tissue GLUT4 deregulation in the pathogenesis of insulin resistance, obesity, and diabetes is still unclear. In this study, we assessed the relative GLUT4 level in human subcutaneous adipose tissue from obese, diabetic, and diabetic obese versus control subjects, using a real-time PCR method. GLUT4 mRNA levels were considerably decreased among type 2 diabetic patients compared with those of the controls (P < 0.01), whereas no such difference was found between obese and normal-weight controls. Multiple linear regressions analysis in both diabetic non-obese and diabetic obese groups showed a negative correlation between GLUT4 mRNA expression and both markers of obesity or insulin resistance (P < 0.01). However, in obese group, GLUT4 was inversely associated only with HOMA-IR (P < 0.01). Our findings showed that adipose GLUT4 gene expression changes were more related to insulin resistance and type 2 diabetes rather than to obesity.

Prevalence of metabolic syndrome in a cohort of Chinese schoolchildren: comparison of two definitions and assessment of adipokines as components by factor analysis

BACKGROUND

Although attention to metabolic syndrome (MetS) in children has increased, there is still no universally accepted definition and its pathogenesis remains unclear. Our aim was to compare the current definitions of childhood MetS in a Chinese cohort and to examine the clustering pattern of MetS risk factors, particularly inclusion of leptin and adiponectin as additional components.

METHODS

3373 schoolchildren aged 6 to 18 years were recruited. Anthropometric and biochemical parameters and adipokines were measured. MetS was identified using both the International Diabetes Federation (IDF) and a modified Adult Treatment Panel III (ATP III) definitions. Exploratory factor analysis was performed to establish grouping of metabolic characteristics.

RESULTS

For children ≥ 10 years, the prevalence of MetS was 14.3% in the obese group and 3.7% in the overweight group according to the new IDF definition, and 32.3% in the obese group and 8.4% in the overweight group according to the modified ATPIII definition. Frequency of hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), impaired fasting glucose, elevated blood pressure, and central obesity according to the new IDF definition was 16.7%, 20.7%, 15.8%, 25.5% and 75.5% in obese boys and 14.7%, 24.0%, 12.0%, 11.0% and 89.0% in obese girls, respectively. Metabolic abnormalities in children under 10 years of age were also noted. Using factor analysis on eight conventional variables led to the extraction of 3 factors. Waist circumference (WC) provided a connection between two factors in boys and all three factors in girls, suggesting its central role in the clustering of metabolic risk factors. Addition of leptin and adiponectin also led to the extraction of 3 factors, with leptin providing a connection between two factors in girls. When using WC, mean arterial pressure, triglyceride/HDL-C ratio, HOMA-IR and leptin/adiponectin ratio as variables, a single-factor model was extracted. WC had the biggest factor loading, followed by leptin/adiponectin ratio.

CONCLUSIONS

MetS was highly prevalent amongst obese children and adolescents in this cohort, regardless of the definition used. Central obesity is the key player in the clustering of metabolic risk factors in children, supporting the new IDF definition. Moreover, our findings suggest that a common factor may underlie MetS. Leptin/adiponectin ratio as a possible component of MetS deserves further consideration.

Adiposity and hyperglycaemia in pregnancy and related health outcomes in European ethnic minorities of Asian and African origin: a review

BACKGROUND

Ethnic minorities in Europe have high susceptibility to type 2 diabetes (T2DM) and, in some groups, also cardiovascular disease (CVD). Pregnancy can be considered a stress test that predicts future morbidity patterns in women and that affects future health of the child.

OBJECTIVE

TO REVIEW ETHNIC DIFFERENCES IN: 1) adiposity, hyperglycaemia, and pre-eclampsia during pregnancy; 2) future risk in the mother of obesity, T2DM and CVD; and 3) prenatal development and possible influences of maternal obesity, hyperglycaemia, and pre-eclampsia on offspring's future disease risk, as relevant for ethnic minorities in Europe of Asian and African origin.

DESIGN

Literature review.

RESULTS

Maternal health among ethnic minorities is still sparsely documented. Higher pre-pregnant body mass index (BMI) is found in women of African and Middle Eastern descent, and lower BMI in women from East and South Asia compared with women from the majority population. Within study populations, risk of gestational diabetes mellitus (GDM) is considerably higher in many minority groups, particularly South Asians, than in the majority population. This increased risk is apparent at lower BMI and younger ages. Women of African origin have higher risk of pre-eclampsia. A GDM pregnancy implies approximately seven-fold higher risk of T2DM than normal pregnancies, and both GDM and pre-eclampsia increase later risk of CVD. Asian neonates have lower birth weights, and mostly also African neonates. This may translate into increased risks of later obesity, T2DM, and CVD. Foetal overgrowth can promote the same conditions. Breastfeeding represents a possible strategy to reduce risk of T2DM in both the mother and the child.

CONCLUSIONS

Ethnic minority women in Europe with Asian and African origin and their offspring seem to be at increased risk of T2DM and CVD, both currently and in the future. Pregnancy is an important window of opportunity for short and long-term disease prevention.

Pathophysiology of human visceral obesity: an update

Excess intra-abdominal adipose tissue accumulation, often termed visceral obesity, is part of a phenotype including dysfunctional subcutaneous adipose tissue expansion and ectopic triglyceride storage closely related to clustering cardiometabolic risk factors. Hypertriglyceridemia; increased free fatty acid availability; adipose tissue release of proinflammatory cytokines; liver insulin resistance and inflammation; increased liver VLDL synthesis and secretion; reduced clearance of triglyceride-rich lipoproteins; presence of small, dense LDL particles; and reduced HDL cholesterol levels are among the many metabolic alterations closely related to this condition. Age, gender, genetics, and ethnicity are broad etiological factors contributing to variation in visceral adipose tissue accumulation. Specific mechanisms responsible for proportionally increased visceral fat storage when facing positive energy balance and weight gain may involve sex hormones, local cortisol production in abdominal adipose tissues, endocannabinoids, growth hormone, and dietary fructose. Physiological characteristics of abdominal adipose tissues such as adipocyte size and number, lipolytic responsiveness, lipid storage capacity, and inflammatory cytokine production are significant correlates and even possible determinants of the increased cardiometabolic risk associated with visceral obesity. Thiazolidinediones, estrogen replacement in postmenopausal women, and testosterone replacement in androgen-deficient men have been shown to favorably modulate body fat distribution and cardiometabolic risk to various degrees. However, some of these therapies must now be considered in the context of their serious side effects. Lifestyle interventions leading to weight loss generally induce preferential mobilization of visceral fat. In clinical practice, measuring waist circumference in addition to the body mass index could be helpful for the identification and management of a subgroup of overweight or obese patients at high cardiometabolic risk.

Retinol binding protein-4 circulating levels were higher in nonalcoholic fatty liver disease vs. histologically normal liver from morbidly obese women

OBJECTIVE

We aimed to analyze the retinol binding protein-4 (RBP4) messenger RNA (mRNA) expression profiles in adipose tissues and liver of morbidly obese (MO) women with or without nonalcoholic fatty liver disease (NAFLD), and to study the relationships with other pro- and anti-inflammatory adipokines in vivo and in vitro.

DESIGN AND METHODS

We performed a cross-sectional analysis of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and liver samples from four lean and 45 MO women with or without NAFLD by enzyme-linked immunosorbent assay and real-time reverse transcription-PCR. We also studied RBP4 expression in HepG2 hepatocytes under various inflammatory stimuli.

RESULTS

Circulating RBP4 levels were higher in MO women, and specifically, in MO subjects with NAFLD compared with normal liver controls (lean and MO). RBP4 liver expression was higher in nonalcoholic steatohepatitis (NASH)-moderate/severe than in NASHmild. Overall RBP4 gene expression was higher in liver than in adipose tissues. Among them, the higher expression corresponded to SAT. VAT expression was lower in the MO cohort. In HepG2, RBP4 mRNA expression was reduced by tumor necrosis factor (TNF)-α and increased by adiponectin treatment.

CONCLUSIONS

The results obtained in MO women with NAFLD, brings up the use of RBP4 and other adipokines as a panel of noninvasive molecular biomarkers when NAFLD is suspected. Further studies are needed with other obesity groups.

Role of peripheral blood mononuclear cells in the predisposition of obese individuals to inflammation and infection

OBJECTIVE

To compare the production of pro- and anti-inflammatory cytokines by peripheral blood mononuclear cells (PBMC) from obese but otherwise healthy individuals to that of normal-weight volunteers.

METHODS

25 healthy normal-weight subjects and 41 obese individuals were enrolled. Weight and height were measured twice. PBMC were examined for their capacity to generate pro-inflammatory (TNF-α, IFN-γ, IL-1β, IL-6, IL-2) and anti-inflammatory IL-10 and IL-1ra) cytokines.

RESULTS

PBMC from obese individuals, compared to those from subjects with normal weight showed an increased production of the pro-inflammatory cytokines IL-2 (6.7 ± 0.4. vs. 4.9 ± 0.3 ng/ml; p = 0.003), TNF-α (505 ± 45 vs. 277 ± 32 pg/ml; p = 0.001), and IFN-γ (93.8 ± 6.0 vs. 73.9 ± 2.7 ng/ml; p = 0.0016). However, PBMC from obese individuals produced a lower amount of the anti-inflammatory cytokine IL-10 (651 ±72 pg/ml) versus those from subjects with normal weight (951 ± 133 pg/ml; p = 0.039).

CONCLUSIONS

The findings imply that obese individuals are in a 'low-grade inflammatory state', presumed to be connected with metabolic and cardiovascular co morbidities. The surplus of pro-inflammatory cytokines produced by circulating mononuclear cells of obese individuals, together with those secreted by adipocytes and non-fat cells in the adipose tissue, may contribute to the predisposition of obese patients to inflammation and infections.

Case-control study of markers of insulin resistance and endometrial cancer risk

Markers of insulin resistance such as the adiponectin:leptin ratio (A:L) and the homeostasis model assessment ratio (HOMA-IR) are associated with obesity and hyperinsulinemia, both established risk factors for endometrial cancer, and may therefore be informative regarding endometrial cancer risk. This study investigated the association between endometrial cancer risk and markers of insulin resistance, namely adiponectin, leptin, the A:L ratio, insulin, fasting glucose, and the HOMA-IR. We analyzed data from 541 incident endometrial cancer cases and 961 frequency age-matched controls in a population-based case-control study in Alberta, Canada from 2002 to 2006. Participants completed interview-administered questionnaires were assessed for anthropometric measures, and provided 8-h fasting blood samples either pre- or postoperatively. Blood was analyzed for concentrations of leptin, adiponectin, and insulin by immunoassay, and fasting plasma glucose levels were determined by fluorimetric quantitative determination. Compared with the lowest quartile, the highest quartile of insulin and HOMA-IR was associated with 64% (95% confidence intervals (CI): 1.12-2.40) and 72% (95% CI: 1.17-2.53) increased risks of endometrial cancer, respectively, and the highest quartile of adiponectin was associated with a 45% (95% CI: 0.37-0.80) decreased risk after multivariable adjustments. Null associations were observed between fasting glucose, leptin and A:L, and endometrial cancer risk. This population-based study provides evidence for a role of insulin resistance in endometrial cancer etiology and may provide one possible pathway whereby obesity increases the risk of this common cancer. Interventions aimed at decreasing both obesity and insulin resistance may decrease endometrial cancer risk.

The adipokine adiponectin has potent anti-fibrotic effects mediated via adenosine monophosphate-activated protein kinase: novel target for fibrosis therapy

Introduction

Fibrosis in scleroderma is associated with collagen deposition and myofibroblast accumulation. Peroxisome proliferator activated receptor gamma (PPAR-γ), a master regulator of adipogenesis, inhibits profibrotic responses induced by transforming growth factor-ß (TGF-β), and its expression is impaired in scleroderma. The roles of adiponectin, a PPAR-γ regulated pleiotropic adipokine, in regulating the response of fibroblasts and in mediating the effects of PPAR-γ are unknown.

Methods

Regulation of fibrotic gene expression and TGF-ß signaling by adiponectin and adenosine monophosphate protein-activated (AMP) kinase agonists were examined in normal fibroblasts in monolayer cultures and in three-dimensional skin equivalents. AdipoR1/2 expression on skin fibroblasts was determined by real-time quantitative PCR.

Results

Adiponectin, an adipokine directly regulated by PPAR-γ, acts as a potent anti-fibrotic signal in normal and scleroderma fibroblasts that abrogates the stimulatory effects of diverse fibrotic stimuli and reduces elevated collagen gene expression in scleroderma fibroblasts. Adiponectin responses are mediated via AMP kinase, a fuel-sensing cellular enzyme that is necessary and sufficient for down-regulation of fibrotic genes by blocking canonical Smad signaling. Moreover, we demonstrate that endogenous adiponectin accounts, at least in part, for the anti-fibrotic effects exerted by ligands of PPAR-γ.

Conclusions

These findings reveal a novel link between cellular energy metabolism and extracellular matrix homeostasis converging on AMP kinase. Since the levels of adiponectin as well as its receptor are impaired in scleroderma patients with progressive fibrosis, the present results suggest a potential role for defective adiponectin expression or function in progressive fibrogenesis in scleroderma and other chronic fibrosing conditions. Restoring the adiponectin signaling axis in fibroblasts might, therefore, represent a novel pharmacological approach to controlling fibrosis.

Preliminary evidence for obesity-associated insulin resistance in adolescents without elevations of inflammatory cytokines

BACKGROUND

To ascertain whether the associations between obesity, inflammation, and insulin resistance established in human adult studies are found among adolescents.

METHODS

We contrasted 36 obese and 24 lean youth on fasting glucose, insulin levels, lipid profile, hemoglobin A1C, markers of hepatic function, white blood cell count, C-reactive protein (CRP) and fibrinogen levels. The cytokines IL-6, TNF-α, IFN-γ, IL-10 and IL-4 and the adipokines leptin, resistin, and adiponectin were also compared between the two groups. The fasting glucose and insulin values were used to estimate the degree of insulin resistance with the homeostatic model assessment of insulin resistance (HOMA-IR). T-tests and correlations were run to examine group differences and associations between groups. In addition, regression analyses were used to ascertain whether the markers of inflammation were predictive of the degree of insulin resistance.

RESULTS

Although obese adolescents had clear evidence of insulin resistance, only CRP, fibrinogen and leptin were elevated; there were no group differences in pro- or anti-inflammatory cytokines nor adiponectin and resistin. Anthropometric measures of obesity and level of insulin resistance were highly correlated to the acute phase reactants CRP and fibrinogen; however, the degree of insulin resistance was not predicted by the pro- or anti-inflammatory cytokine markers. Obese adolescents had higher white blood cell counts. In addition they had higher circulating alanine aminotransferase concentrations and lower circulating albumin and total protein than lean adolescents, possibly as a result of hepatocyte damage from fatty liver.

CONCLUSION

Unlike rodent or adult studies, we found that wide-spread systemic inflammation is not necessarily associated with insulin resistance among adolescents. This finding does not support the current paradigm that the associations between obesity and insulin resistance are, to a significant degree, mediated by low grade systemic inflammation. These data support the need for further adolescent studies to explore these associations.

Resistin: functional roles and therapeutic considerations for cardiovascular disease

Resistin, originally described as an adipocyte-specific hormone, has been suggested to be an important link between obesity, insulin resistance and diabetes. Although its expression was initially defined in adipocytes, significant levels of resistin expression in humans are mainly found in mononuclear leukocytes, macrophages, spleen and bone marrow cells. Increasing evidence indicates that resistin plays important regulatory roles apart from its role in insulin resistance and diabetes in a variety of biological processes: atherosclerosis and cardiovascular disease (CVD), non-alcoholic fatty liver disease, autoimmune disease, malignancy, asthma, inflammatory bowel disease and chronic kidney disease. As CVD accounts for a significant amount of morbidity and mortality in patients with diabetes and without diabetes, it is important to understand the role that adipokines such as resistin play in the cardiovascular system. Evidence suggests that resistin is involved in pathological processes leading to CVD including inflammation, endothelial dysfunction, thrombosis, angiogenesis and smooth muscle cell dysfunction. The modes of action and signalling pathways whereby resistin interacts with its target cells are beginning to be understood. In this review, the current knowledge about the functions and pathophysiological implications of resistin in CVD development is summarized; clinical translations, therapeutic considerations and future directions in the field of resistin research are discussed.

LINKED ARTICLES

This article is part of a themed section on Fat and Vascular Responsiveness. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-3.

Resistin: functional roles and therapeutic considerations for cardiovascular disease

Resistin, originally described as an adipocyte-specific hormone, has been suggested to be an important link between obesity, insulin resistance and diabetes. Although its expression was initially defined in adipocytes, significant levels of resistin expression in humans are mainly found in mononuclear leukocytes, macrophages, spleen and bone marrow cells. Increasing evidence indicates that resistin plays important regulatory roles apart from its role in insulin resistance and diabetes in a variety of biological processes: atherosclerosis and cardiovascular disease (CVD), non-alcoholic fatty liver disease, autoimmune disease, malignancy, asthma, inflammatory bowel disease and chronic kidney disease. As CVD accounts for a significant amount of morbidity and mortality in patients with diabetes and without diabetes, it is important to understand the role that adipokines such as resistin play in the cardiovascular system. Evidence suggests that resistin is involved in pathological processes leading to CVD including inflammation, endothelial dysfunction, thrombosis, angiogenesis and smooth muscle cell dysfunction. The modes of action and signalling pathways whereby resistin interacts with its target cells are beginning to be understood. In this review, the current knowledge about the functions and pathophysiological implications of resistin in CVD development is summarized; clinical translations, therapeutic considerations and future directions in the field of resistin research are discussed.

LINKED ARTICLES

This article is part of a themed section on Fat and Vascular Responsiveness. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-3.

Differential responses of white adipose tissue and brown adipose tissue to caloric restriction in rats

Caloric restriction (CR) slows the aging process and extends longevity, but the exact underlying mechanisms remain debatable. It has recently been suggested that the beneficial action of CR may be mediated in part by adipose tissue remodeling. Mammals have two types of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT). In this study, proteome analysis using two-dimensional gel electrophoresis combined with MALDI-TOF MS, and subsequent analyses were performed on both WAT and BAT from 9-month-old male rats fed ad libitum or subjected to CR for 6 months. Our findings suggest that CR activates mitochondrial energy metabolism and fatty acid biosynthesis in WAT. It is likely that in CR animals WAT functions as an energy transducer from glucose to energy-dense lipid. In contrast, in BAT CR either had no effect on, or down-regulated, the mitochondrial electron transport chain, but enhanced fatty acid biosynthesis. This suggests that in CR animals BAT may change its function from an energy consuming system to an energy reservoir system. Based on our findings, we conclude that WAT and BAT cooperate to use energy effectively via a differential response of mitochondrial function to CR.

Melatonin improves glucose homeostasis in young Zucker diabetic fatty rats

The aim of this study was to investigate the effects of melatonin on glucose homeostasis in young male Zucker diabetic fatty (ZDF) rats, an experimental model of metabolic syndrome and type 2 diabetes mellitus (T2DM). ZDF rats (n=30) and lean littermates (ZL) (n=30) were used. At 6wk of age, both lean and fatty animals were subdivided into three groups, each composed of ten rats: naive (N), vehicle treated (V), and melatonin treated (M) (10mg/kg/day) for 6wk. Vehicle and melatonin were added to the drinking water. ZDF rats developed DM (fasting hyperglycemia, 460±39.8mg/dL; HbA(1) c 8.3±0.5%) with both insulin resistance (HOMA-IR 9.28±0.9 versus 1.2±0.1 in ZL) and decreased β-cell function (HOMA1-%B) by 75%, compared with ZL rats. Melatonin reduced fasting hyperglycemia by 18.6% (P<0.05) and HbA(1) c by 11% (P<0.05) in ZDF rats. Also, melatonin lowered insulinemia by 15.9% (P<0.05) and HOMA-IR by 31% (P<0.01) and increased HOMA1-%B by 14.4% (P<0.05). In addition, melatonin decreased hyperleptinemia by 34% (P<0.001) and raised hypoadiponectinemia by 40% (P<0.001) in ZDF rats. Moreover, melatonin reduced serum free fatty acid levels by 13.5% (P<0.05). These data demonstrate that oral melatonin administration ameliorates glucose homeostasis in young ZDF rats by improving both insulin action and β-cell function. These observations have implications on melatonin's possible use as a new pharmacologic therapy for improving glucose homeostasis and of obesity-related T2DM, in young subjects.

A meta-analysis of the association of adiponectin gene polymorphisms with coronary heart disease in Chinese Han population

OBJECTIVE

  Variants of adiponectin gene have been reported to be associated with coronary heart disease (CHD), but the available data on this relationship are inconsistent. A meta-analysis was performed to quantitatively analyse the association of adiponectin gene polymorphisms with coronary artery disease using previous case-control studies in Chinese Han populations.

METHODS

  Several electronic databases were searched for relevant articles up to January 2011. After data collection and gene loci selection, a meta-analysis was performed to assess heterogeneity, combine results and evaluate variations. Publication bias was examined by the Egger's linear regression test. Hardy-Weinberg equilibrium (HWE) test and by omitting one study at a time was employed for the sensitivity analysis.

RESULTS

  Eleven studies covering 4303 subjects focusing on two polymorphisms [+45T→G (rs2241766) and +276G→T (rs1501299)] in the adiponectin gene and risk of CHD were included in the meta-analysis. Combined analyses of studies of the SNP+45 showed no significant overall association with CHD, yielding ORs of 1·03 (0·80, 1·34) and 1·32 (0·86, 2·03) under a dominant and recessive model, respectively, with strong evidence of heterogeneity. Similar results were also obtained in other genetic models. Concerning SNP+276, a significantly decreased CHD risk was observed under a dominant model, a codominant model and a allele contrast model, with an odds ratio of 0·67 (0·54, 0·83), 0·77 (0·62, 0·94) and 0·69 (0·55, 0·86), respectively. Sensitivity analysis confirmed the reliability and stability of this meta-analysis.

CONCLUSIONS

  The accumulated evidence suggested that the adiponectin gene polymorphism, SNP+45, is not associated with CHD, but the SNP+276T allele might be associated with decreased risk of CHD in the Chinese Han population. More well-designed large studies are required for the validation of this association.

Adipose tissue in the pathophysiology of cardiovascular disease: Who is guilty?

Epidemiological evidence has shown how abdominal obesity is closely associated with the development of cardiovascular disease. It has been demonstrated that patients with extensive adipose tissue usually have other concomitant cardiovascular risk factors, such insulin resistance, hypertension and dyslipidemia. Moreover, obese patients have a significantly higher risk of developing thrombophilic events compared with the non-obese. Thus, obesity is actually considered an independent cardiovascular risk factor. The pathophysiological mechanisms responsible for the association between obesity and cardiovascular disease remain largely unknown. However, it has been postulated that obese patients have an “inflammatory milieu” responsible for their metabolic disorders and vascular disease. In this context, adipocyte-derived molecules with inflammatory activity might play a pivotal role in the development of these mechanisms. In the present report, we provide an updated overview on the molecules produced by adipose tissue that are potentially involved in cardiovascular pathophysiology.

Screening for adiponectin secretion regulators

Adiponectin is an adipokine secreted from adipocytes and plays important roles in the suppression of metabolic syndromes that can result in type 2 diabetes, obesity, and atherosclerosis. Adiponectin is a promising drug target because a number of studies have shown that upregulation of adiponectin has a number of therapeutic benefits. Extensive efforts have revealed various adiponectin regulators, such as cytokines, transcription factors, and drugs. Cytokines, such as tumor necrosis factor α, IL-6, and IL-18, downregulate adiponectin production. On the other hand, transcription factors such as peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT-enhancer-binding protein α, and forkhead box O1 (FoxO1) upregulate adiponectin expression, although the activating transcription factor 3 and cAMP response element-binding protein downregulate it. Although a number of therapeutic drugs have been reported as adiponectin secretion regulators, most of them act through PPARγ-dependent mechanisms, leaving PPARγ-derived side effects as a concern. Using high-throughput screening, we have identified PPARγ-independent adiponectin secretion regulators as potential drug candidates with a novel mechanism of action.

Quantitative comparison of adipocytokine gene expression during adipocyte maturation in non-obese and obese rats

Adipocytokines secreted from adipocytes have been extensively analyzed due to their role as key factors in various complications of obesity, including arterial sclerosis, liver steatosis, insulin resistance, and diabetes. Several in vivo and in vitro studies have suggested that adipocyte maturation is related to fluctuations in adipocytokine secretion. However, the relationship between adipocyte maturation and adipocytokine levels has not been fully elucidated. Therefore, we sought to clarify the link between adipocytokine gene expression and adipocyte maturation through systematic analysis. We quantified mRNA for six adipocytokine genes: adiponectin, resistin, leptin, plasminogen activator inhibitor 1 (PAI-1), heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), and visfatin, in adipose tissue, in primary cultured adipocytes obtained from an obese Zucker rat, and in the preadipocyte cell line 3T3-L1. Moreover, to elucidate the role of adipocytokines in adipocyte maturation, adipocytokine expression levels were analyzed during maturation. Although fluctuations in adipocytokine gene expression were heterogeneous, gene expression was highly similar during maturation of primary cultured adipocytes from obese and non-obese rats, suggesting that the maturation process is independent from processes that lead to obesity. Moreover, the expression patterns of adiponectin, resistin and leptin mRNA in 3T3-L1 cells were highly similar to those in primary cultured adipocytes, indicating that these adipocytokines could be common maturation markers for primary cultured adipocytes obtained from obese and non-obese rats, and for preadipocyte cell lines.

Early endocrine and molecular changes in metabolic syndrome models

The twenty-first century arrived in the middle of a global epidemic of metabolic syndrome (MS) and type 2 diabetes mellitus (DM2). It is generally accepted that an excess of nutrients linked to a low physical activity triggers the problem. However, the molecular features that interact to develop the MS are not clear. In an effort to understand and control them, they have been extensively studied, but this goal has not been achieved yet. Nonhuman animal models have been used to explore diet and genetic factors in which experimental conditions are controlled. For example, only one factor in the diet, such as fats or carbohydrates can be modified to better understand a single change that would be impossible in humans. Most of the studies have been done in rodents. However, it is difficult to directly compare them, because experiments are different in more than one variable; genetic strains, amount, and the type of fat used in the diet and sex. Thus, the only possible criteria of comparison are the relevance of the observed changes. We review different animal models and add some original observations on short-term changes in metabolism and beta cells in our own model of adult Wistar rats that are not especially prone to get fat or develop DM2, treated with 20% sucrose in drinking water. One early change observed in pancreatic beta cells is the increase in GLUT2 expression that is located to the membrane of the cells. This change could partially explain the presence of insulin hypersecretion and hyperinsulinemia in these rats. Understanding early changes that lead to MS and in time to pancreatic islet exhaustion is an important biomedical problem that may contribute to learn how to prevent or even reverse MS, before developing DM2.

Adipose tissue expression of interleukin-18 mRNA is elevated in subjects with metabolic syndrome and independently associated with fasting glucose

BACKGROUND

The metabolic syndrome (MetS) is a cluster of risk factors that are highly associated with increased risk for cardiovascular disease (CVD). Increased serum levels of plasminogen activator inhibitor-1 (PAI-1), interleukin-6 (IL-6) and IL-18 have been reported to be associated with CVD. Recently, IL-18 has been shown to be predictive for cardiovascular events in subjects with MetS. We have investigated the expression of PAI-1, IL-6 and IL-18 in subcutaneous adipose tissue (AT) of subjects with (n = 22) and without (n = 36) MetS. Furthermore, we have analysed the expression of IL-18 in monocyte-derived macrophages (MDMs) in an in vitro model of hyperglycaemia.

METHODS

We studied the expression of PAI-1, IL-6 and IL-18 in biopsies of subcutaneous adipose tissue using Real-time PCR. After isolation and cultivation of MDMs, expression of IL-18 was determined by Real-time PCR.

RESULTS

Expression of IL-18 was increased in subcutaneous AT of subjects with MetS (p < 0.05). Multivariate analysis revealed fasting plasma glucose to be the only MetS component being independently associated with expression of IL-18 in AT (p < 0.05). Exposure to hyperglycaemia, increased in expression of IL-18 in MDMs (p < 0.01).

CONCLUSION

Our findings suggest that subjects with MetS have a particular inflammatory pattern in AT, possibly driven by fasting glucose. MDMs might - at least in part - be the cellular source of this increased expression. Together with recent reports, showing IL-18 to be predictive for cardiovascular events, our findings could provide the basis for further research of the role of IL-18 as a link and possible target in the association between MetS and atherosclerosis.

Circulating interleukin-1β and interleukin-6 concentrations are closely associated with γ-glutamyltranspeptidase activity in middle-aged Japanese men without obvious cardiovascular diseases

Interleukin (IL)-1β and IL-6 expressions are known to be induced by oxidant stress. In the present study, we examined the relationships between these interleukins and the activity of γ-glutamyltranspeptidase (γ-GTP), which was recently reported as a source of oxidant stress production, in the circulating blood of middle-aged Japanese men without obvious cardiovascular diseases. We conducted a cross-sectional study of 317 Japanese men without obvious cardiovascular diseases aged 40 to 69 years (mean ± SD, 58.6 ± 7.6 years) who participated in health checkups in Japan. We analyzed their clinical parameters in serum, lifestyle factors, and plasma IL-1β and IL-6 concentrations. We compared the relationships between these interleukin concentrations and the clinical parameters and lifestyle factors by Spearman correlation coefficients. Stepwise multiple linear regression analyses for interleukins based on the other parameters and γ-GTP, which were classified into 3 groups according to the concentrations, were performed. Interleukin-1β and IL-6 concentrations were closely associated with γ-GTP activity but less associated with alanine aminotransferase and aspartate aminotransferase activities by Spearman correlation coefficients. Stepwise multiple linear regression analyses showed that γ-GTP activity was the explanatory variable for elevated IL-1β and IL-6 concentrations. As natural logarithms, the IL-1β and IL-6 concentrations were estimated to be 1.734- and 1.157-fold higher, respectively, in subjects with high γ-GTP activity ranges than in subjects with a low γ-GTP activity range. The present results show that circulating IL-1β and IL-6 concentrations are strongly and independently associated with γ-GTP activity in middle-aged Japanese men without obvious cardiovascular diseases.

High-throughput screening for small-molecule adiponectin secretion modulators

Adiponectin is an adipokine secreted by adipocytes and plays a role in the suppression of metabolic disorders that can result in type 2 diabetes, obesity, and atherosclerosis. Several studies have shown that upregulation of adiponectin has a number of therapeutic benefits. Although peroxisome proliferator-activated receptor γ (PPARγ) agonists are known to increase adiponectin secretion both in cultured adipocytes and humans, they have several side effects, such as weight gain, congestive heart failure, and edema. Therefore, adiponectin secretion modulators that do not possess PPARγ agonistic activity seem to promising for a number of conditions. Here, the authors report on the development of a reporter-based high-throughput screening (HTS) assay using insulin-resistant-mimic 3T3-L1 adipocytes for discovery of adiponectin secretion modulators. They screened a library of approximately 100 000 small-molecule compounds using this model, performed several follow-up screens, and identified six hit compounds that increase adiponectin secretion without having PPARγ agonistic activity. These compounds may be useful drug candidates for diabetes, obesity, atherosclerosis, and other metabolic syndromes. This HTS assay might be applicable to screening for other adipokine modulators that can be useful for the treatment of other conditions.

The STRATOB study: design of a randomized controlled clinical trial of Cognitive Behavioral Therapy and Brief Strategic Therapy with telecare in patients with obesity and binge-eating disorder referred to residential nutritional rehabilitation

BACKGROUND

Overweight and obesity are linked with binge eating disorder (BED). Effective interventions to significantly reduce weight, maintain weight loss and manage associated pathologies like BED are typically combined treatment options (dietetic, nutritional, physical, behavioral, cognitive-behavioral, pharmacological, surgical). Significant difficulties with regard to availability, costs, treatment adherence and long-term efficacy are present. Particularly Cognitive Behavioral Therapy (CBT) is the therapeutic approach indicated both in in-patient and in out-patient settings for BED. In recent years systemic and systemic-strategic psychotherapies have been implemented to treat patients with obesity and BED involved in familiar problems. Particularly a brief protocol for the systemic-strategic treatment of BED, using overall the strategic dialogue, has been recently developed. Moreover telemedicine, a new promising low cost method, has been used for obesity with BED in out-patient settings in order to avoid relapse after the in-patient step of treatment and to keep on a continuity of care with the involvement of the same clinical in-patient team.

METHODS

The comparison between CBT and Brief Strategic Therapy (BST) will be assessed in a two-arm randomized controlled clinical trial. Due to the novelty of the application of BST in BED treatment (no other RCTs including BST have been carried out), a pilot study will be carried out before conducting a large scale randomized controlled clinical trial (RCT). Both CBT and BST group will follow an in-hospital treatment (diet, physical activity, dietitian counseling, 8 psychological sessions) plus 8 out-patient telephone-based sessions of psychological support and monitoring with the same in-patient psychotherapists. Primary outcome measure of the randomized trial will be the change in the Global Index of the Outcome Questionnaire (OQ-45.2). Secondary outcome measures will be the percentage of BED patients remitted considering the number of weekly binge episodes and the weight loss. Data will be collected at baseline, at discharge from the hospital (c.a. 1 month after) and after 6-12-24 months from the end of the in-hospital treatment. Data at follow-up time points will be collected through tele-sessions.

DISCUSSION

The STRATOB (Systemic and STRATegic psychotherapy for OBesity), a comprehensive two-phase stepped down program enhanced by telepsychology for the medium-term treatment of obese people with BED seeking intervention for weight loss, will shed light about the comparison of the effectiveness of the BST with the gold standard CBT and about the continuity of care at home using a low-level of telecare (mobile phones).

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01096251

Brief Strategic Therapy vs Cognitive Behavioral Therapy for the Inpatient and Telephone-Based Outpatient Treatment of Binge Eating Disorder: The STRATOB Randomized Controlled Clinical Trial

This paper describes the results of the STRATOB (Systemic and STRATegic psychotherapy for OBesity) study, a two-arm randomized controlled clinical trial (RCT) comparing Brief Strategic Therapy (BST, Nardone or Arezzo model) with the gold standard CBT (Cognitive Behavioral Therapy) for the inpatient and telephone-based outpatient treatment of obese people with Binge Eating Disorder (BED) seeking treatment for weight reduction. Primary outcome measure of the randomized trial was change in the Global Index of the Outcome Questionnaire (OQ 45.2). Secondary outcome measures were BED remission (weekly binge episodes < 2) and weight loss. Data were collected at baseline, at discharge from the hospital (c.a. 1 month after) and after 6 months from discharge.. No significant difference between groups (BST vs CBT) was found in the primary outcome at discharge. However, a greater improvement was seen in the BST vs the CBT group (P<.01) in the primary outcome at 6 months. About secondary outcomes, no significant difference between groups were found in weight change both at discharge and at 6 months. Notably, a significant association emerged between treatment groups and BED remission at 6 months in favor of BST (only 20% of patients in BST group reported a number of weekly binge episodes > 2 vs 63.3% in CBT group).

Reliability of leptin, but not adiponectin, as a biomarker for diet-induced weight loss in humans

Calorie restriction (CR)-induced weight loss has been shown to lower the risk of chronic disease in obese individuals. Although the mechanisms that link weight loss to disease risk reduction remain unclear, evidence suggests adipokines may play a role. What has yet to be determined, however, is the dose-response effect of body weight loss and visceral fat mass loss on adipokines. Accordingly, this review examines how varying degrees of CR-induced weight loss (i.e., >10%, 5-10%, and <5% from baseline) impact plasma levels and expression of adiponectin, leptin, resistin, interleukin 6 (IL-6), interleukin 8 (IL-8), monocyte chemotactic protein 1 (MCP-1), and retinol-binding protein 4 (RBP-4). The dose-response relationship between visceral fat mass loss and adipokine profile improvement will also be explored. Results from this review demonstrate that even mild weight loss induced by CR may have beneficial effects on leptin levels, but it has no clear impact on adiponectin, resistin, IL-6, IL-8, MCP-1, or RBP-4 concentrations.

Influences of the common FTO rs9939609 variant on inflammatory markers throughout a broad range of body mass index

Background

A recent study reported that the fatness associated A-allele of FTO rs9939609 increased plasma high sensitivity C-reactive protein (hs-CRP) levels independent of fatness. We aimed to investigate if this gene variant had fatness-independent effects on plasma hs-CRP and 10 additional circulating obesity-related adipokines throughout a broad range of body mass index (BMI) among Danish men.

Methodology/Principal Findings

In a population of 362,200 young men, examined for military service between 1943 and 1977, two groups were identified: 1) a random 1% sample and 2) all obese men (BMI = 31.0 kg/m², all of whom were above the 99^th percentile of this population). At an average age of 49 years (range: 39 through 65 years), 551 men, hereof 231 of the obese, were re-examined, including genotyping and measurement of the fasting circulating inflammatory markers hs-CRP, IL-1β, IL-6, IL-10, IL-18, mip1α, mip1β, sTNFα-R1, TGF-β, TNF-α and leptin. Men with known disease were excluded from the examination. All the inflammatory markers were log-transformed to approximate a normal distribution. Genotype-phenotype relationships were studied using linear regression analyses with the inflammatory markers as the response variable. Significant positive associations between hs-CRP, leptin and a broad range of BMI were observed, but the associations did not significantly differ across FTO rs9939609 genotype. There were no significant associations between the other inflammatory markers, FTO rs9939609 genotype or BMI, respectively.

Conclusion

No fatness-independent effects of the FTO rs9939609 A-allele on a series of inflammatory markers were observed in this cohort of healthy middle-aged men representing a broad range of fatness.

Energy balance modulates colon tumor growth: Interactive roles of insulin and estrogen

Obesity increases colorectal cancer (CRC) risk and progression. However, the impact of obesity on CRC in women is dependent on ovarian hormone status. The purpose of this study was to determine the interactive roles of obesity and ovarian hormones on serum markers of inflammation, cell signaling, and transplanted colon tumor growth. Female C57BL/6 mice (6 wk) were either ovariectomized (OVX) or ovaries left intact (nonovariectomized, NOVX) and randomized to receive a (1) control, (2) 30% calorie-restricted (CR), or (3) diet-induced obese (DIO) diet regimen for 20 wk to induce differing levels of adiposity. Serum was collected and inflammatory and metabolic markers were measured using an antibody array (62 proteins) and ELISAs. Mice were subcutaneously injected with syngeneic MC38 colon cancer cells after 20 wk and sacrificed 4 wk later. CR mice had the smallest tumors irrespective of hormone status, whereas the largest tumors were observed in DIO-OVX mice. Glucose tolerance was impaired in OVX mice, being most severe in the DIO-OVX group. Cytokine arrays suggested that in CR animals, inhibition of tumor growth paralleled insulin sensitivity and associated changes in leptin, adiponectin, and IGF-BPs. Conversely, in DIO-OVX animals, tumor growth was associated with insulin and leptin resistance as well as higher levels of pro-inflammatory proteins. In vitro, leptin and adiponectin had no effect, whereas insulin induced MC38 cell proliferation and MAPK activation. Co-treatment with estrogen blocked the stimulatory effects of insulin. Thus, our in vitro and in vivo data indicate female reproductive hormones have a modulating effect on obesity-induced insulin resistance and inflammation, which may directly or indirectly influence CRC progression.

Melatonin effect on plasma adiponectin, leptin, insulin, glucose, triglycerides and cholesterol in normal and high fat-fed rats

Melatonin effect on body weight progression, mean levels and 24-hr pattern of circulating adiponectin, leptin, insulin, glucose, triglycerides and cholesterol were examined in rats fed a normal or a high-fat diet. In experiment 1, rats fed a normal diet were divided into two groups: receiving melatonin (25 μg/mL drinking water) or vehicle for 9 wk. In experiment 2, animals were divided into three groups: two fed with a high-fat diet (35% fat) and melatonin (25 μg/mL) or vehicle in drinking water for 11 wk, while a third group was given a normal diet (4% fat). At the end of experiments, groups of eight rats were killed at six different time intervals throughout a 24-hr period. Melatonin administration for 9 wk decreased body weight gain from the 3rd wk on without affecting food intake. A significant reduction in circulating insulin, glucose and triglyceride mean levels and disrupted daily patterns of plasma adiponectin, leptin and insulin were observed after melatonin. In high fat-fed rats, melatonin attenuated body weight increase, hyperglycemia and hyperinsulinemia, as well as the increase in mean plasma adiponectin, leptin, triglycerides and cholesterol levels. The high-fat diet disrupted normal 24-hr patterns of circulating adiponectin, insulin and cholesterol, the effects on insulin and cholesterol being counteracted by melatonin. Nocturnal plasma melatonin concentration in control and obese rats receiving melatonin for 11 wk attained values 21-24-fold greater than controls. The results indicate that melatonin counteracts some of the disrupting effects of diet-induced obesity in rats.