Adiponectin receptors gene expression in lymphocytes of obese and anorexic patients

Comparison of Adiponectin Levels in Anorexia Nervosa, Bulimia Nervosa, Binge-Eating Disorder, Obesity, Constitutional Thinness, and Healthy Controls: A Network Meta-Analysis

Adiponectin is a protein hormone that is produced and secreted primarily by adipose tissue. The levels of adiponectin in those with eating disorders, obesity, and healthy controls have been extensively studied. However, the general picture of the differences in adiponectin levels across the mentioned conditions is still unclear and fragmented. In this study, we pooled previous studies and performed a network meta-analysis to gain a global picture of comparisons of adiponectin levels across eating disorders, obesity, constitutional thinness, and healthy controls. Electronic databases were searched for anorexia nervosa, avoidant restrictive food intake disorder, binge-eating disorder, bulimia nervosa, healthy controls, night eating syndrome, obesity, and constitutional thinness in studies where adiponectin levels were measured. A total of 4262 participants from 50 published studies were included in the network meta-analysis. Adiponectin levels were significantly higher in participants with anorexia nervosa than in healthy controls (Hedges' g = 0.701, p < 0.001). However, adiponectin levels in constitutionally thin participants were not significantly different from those of healthy controls (Hedges' g = 0.470, p = 0.187). Obesity and binge-eating disorder were associated with significantly lower adiponectin levels compared to those of healthy controls (Hedges' g = -0.852, p < 0.001 and Hedges' g = -0.756, p = 0.024, respectively). The disorders characterized by excessive increases or decreases in BMI were associated with significant changes in adiponectin levels. These results suggest that adiponectin may be an important marker of severely disequilibrated homeostasis, especially in fat, glucose, and bone metabolisms. Nonetheless, an increase in adiponectin may not simply be associated with a decrease in BMI, as constitutional thinness is not associated with a significant increase in adiponectin.

Immune disorders in anorexia

Anorexia nervosa is a disease involving eating disorders. It mainly affects young people, especially teenage women. The disease is often latent and occurs in many sub-clinical and partial forms. Approximately from 0.3% to 1% of the population suffers from anorexia. It has been shown that patients with anorexia develop neurotransmitter-related disorders, leading to uncontrolled changes in the immune and endocrine systems. Interactions between cytokines, neuropeptides, and neurotransmitters play an important role in disease development. Significant malnutrition induces disorders and alterations in T-cell populations. The cellular response in patients with anorexia nervosa has been shown to be normal, although opinions on this issue are controversial. Laboratory studies on neutrophils in anorexia patients showed decreased adhesion and reduced bactericidal and cell activities. Despite such unfavourable results, patients with anorexia are resistant to infections, which are very rare in this group. Glutamine improves the performance of the human immune system. The administration of glutamine to anorexia patients, as a supplement to parenteral nutrition, has resulted in significant improvements in immune system parameters. The results of previous studies on the causes and risk factors in the development of anorexia nervosa are still ambiguous. One can hope that the differences and similarities between patients with anorexia nervosa and those with other forms of protein-calorie malnutrition may be helpful in determining the relationship between nutritional status and body defences and susceptibility to infection, and can help to broaden the knowledge about the aetiopathogenesis of anorexia nervosa.

Differential adipokine receptor expression on circulating leukocyte subsets in lean and obese children

BACKGROUND

Childhood obesity prevalence has increased worldwide and is an important risk factor for type 2 diabetes (T2D) and cardiovascular disease (CVD). The production of inflammatory adipokines by obese adipose tissue contributes to the development of T2D and CVD. While levels of circulating adipokines such as adiponectin and leptin have been established in obese children and adults, the expression of adiponectin and leptin receptors on circulating immune cells can modulate adipokine signalling, but has not been studied so far. Here, we aim to establish the expression of adiponectin and leptin receptors on circulating immune cells in obese children pre and post-lifestyle intervention compared to normal weight control children.

METHODS

13 obese children before and after a 1-year lifestyle intervention were compared with an age and sex-matched normal weight control group of 15 children. Next to routine clinical and biochemical parameters, circulating adipokines were measured, and flow cytometric analysis of adiponectin receptor 1 and 2 (AdipoR1, AdipoR2) and leptin receptor expression on peripheral blood mononuclear cell subsets was performed.

RESULTS

Obese children exhibited typical clinical and biochemical characteristics compared to controls, including a higher BMI-SD, blood pressure and circulating leptin levels, combined with a lower insulin sensitivity index (QUICKI). The 1-year lifestyle intervention resulted in stabilization of their BMI-SD. Overall, circulating leukocyte subsets showed distinct adipokine receptor expression profiles. While monocytes expressed high levels of all adipokine receptors, NK and iNKT cells predominantly expressed AdipoR2, and B-lymphocytes and CD4+ and CD8+ T-lymphocyte subsets expressed AdipoR2 as well as leptin receptor. Strikingly though, leukocyte subset numbers and adipokine receptor expression profiles were largely similar in obese children and controls. Obese children showed higher naïve B-cell numbers, and pre-intervention also higher numbers of immature transition B-cells and intermediate CD14++CD16+ monocytes combined with lower total monocyte numbers, compared to controls. Furthermore, adiponectin receptor 1 expression on nonclassical CD14+CD16++ monocytes was consistently upregulated in obese children pre-intervention, compared to controls. However, none of the differences in leukocyte subset numbers and adipokine receptor expression profiles between obese children and controls remained significant after multiple testing correction.

CONCLUSIONS

First, the distinct adipokine receptor profiles of circulating leukocyte subsets may partly explain the differential impact of adipokines on leukocyte subsets. Second, the similarities in adipokine receptor expression profiles between obese children and normal weight controls suggest that adipokine signaling in childhood obesity is primarily modulated by circulating adipokine levels, instead of adipokine receptor expression.

Effect of Diet and Exercise on the Peripheral Immune System in Young Balb/c Mice

Although diet and exercise clearly have an influence on immune function, studies are scarce on the effect caused by exercise and the consumption of a carbohydrate-rich or fat-rich diet on the peripheral immune system. The aim of the present study was to evaluate the effect of exercise and the two aforementioned unbalanced diets on young Balb/c mice, especially in relation to BMI, the level of glucose, and the percentage of lymphocyte subpopulations in peripheral blood. The changes found were then related to the synthesis of leptin and adiponectin as well as the production of oxidative stress. The increase in BMI found with the carbohydrate-rich and fat-rich diets showed correlation with the levels of leptin and adiponectin. An increase in leptin and a decrease in adiponectin directly correlated with an increase in total lymphocytes and CD4+ cells and with a decrease in B cells. The increase in leptin also correlated with an increase in CD8+ cells. Glycemia and oxidative stress increased with the two unbalanced diets, negatively affecting the proliferation of total lymphocytes and the percentage of B cells, apparently by causing alterations in proteins through carbonylation. These alterations caused by an unbalanced diet were not modified by moderate exercise.

Aerobic training increases the expression of adiponectin receptor genes in the peripheral blood mononuclear cells of young men

Little is known about the effect of exercise training on the expression of adiponectin receptor genes in peripheral blood mononuclear cells (PBMCs). In this study, we investigated the effects of aerobic training on the expression of AdipoR1 and AidpoR2 mRNAs in PBMCs, whole body insulin sensitivity, and circulating adiponectins in men. Thirty young men were randomly assigned to either a control (n=15) or an exercise (n=15) group. Subjects assigned to the exercise group underwent a 12-week jogging and/or running programme on a motor-driven treadmill at an intensity of 60%-75% of the age-based maximum heart rate with duration of 40 minutes per session and a frequency of 5 days per week. Two-way mixed ANOVA with repeated measures was used to test any significant time-by-group interaction effects for the measured variables at p=0.05. We found significant time-by-group interaction effects for waist circumference (p=0.001), VO2max (p<0.001), fasting insulin (p=0.016), homeostasis model assessment for insulin resistance (HOMA-IR) (p=0.010), area under the curve (AUC) for insulin response during the 75-g oral glucose tolerance test (p=0.002), high-molecular weight (HMW) adiponectin (p=0.016), and the PBMC mRNA levels of AdipoR1 (p<0.001) and AdipoR2 (p=0.001). The exercise group had significantly increased mRNA levels of AdipoR1 and AdipoR2 in PBMCs, along with increased whole body insulin sensitivity and HMW adiponectin, decreased waist circumference, and increased VO2max compared with the control group. In summary, the current findings suggest that exercise training modulates the expression of AdipoR1 and AdipoR2 mRNAs in PBMCs, implying that manipulation of the expression of these genes could be a potential surrogate for lifestyle intervention-mediated improvements of whole body insulin sensitivity and glucose homeostasis.

Adiponectin in eating disorders

PURPOSE

To elucidate the possible role of adiponectin, an adipokine secreted by white adipose tissue that plays an important role in the neuromodulation of food intake, in the pathogenesis of eating disorders.

METHODS

A comprehensive review of the available literature via MedLine is done using the term "adiponectin" in association with one of the following terms: "anorexia nervosa", "bulimia nervosa", "binge eating disorder" or "eating disorders".

RESULTS

The majority of studies evaluating serum adiponectin levels in patients with eating disorders show that serum adiponectin levels are increased in patients with anorexia nervosa. After refeeding, adiponectin levels tend to rejoin the levels of healthy individuals. Data concerning serum adiponectin levels in patients with bulimia nervosa show that these levels can be equal, higher or lower than those found in healthy controls and lower than those found in anorexia nervosa patients. Binge eating disorder is accompanied with lower serum adiponectin levels than normal. Adiponectin receptor type 1 seems to be more related to the central pathological effect of adiponectin on eating behavior.

CONCLUSION

The potential role that plays adiponectin in the pathogenesis of eating disorders needs to be elucidated by further studies.

Non-hodgkin lymphoma and circulating markers of inflammation and adiposity in a nested case-control study: the multiethnic cohort

BACKGROUND

Because immune dysfunction is thought to underlie the development of non-Hodgkin lymphoma (NHL), obesity and chronic inflammation may be involved in its etiology. We examined the association of prediagnostic inflammatory markers and adipokines with NHL risk.

METHODS

We conducted a nested case-control analysis (272 cases and 541 matched controls) within the Multiethnic Cohort. Luminex technology was used to measure a 10-plex panel of cytokines, ELISA assays for adipokines, and an autoanalyzer for C-reactive protein (CRP). ORs and 95% confidence intervals (CI) for tertiles of analytes were estimated by conditional logistic regression.

RESULTS

After a median time of 2.7 years from phlebotomy to diagnosis, interleukin (IL)-10 was significantly related to NHL risk (ORT3 vs. T1 = 3.07; 95%CI, 2.02-4.66; Ptrend < 0.001). TNF-α and IL-8 showed borderline elevated risks, whereas IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, and CRP were not associated with NHL. Leptin but not adiponectin was related to NHL risk (ORT3 vs. T1 = 0.48; 95%CI, 0.30-0.76; Ptrend < 0.001). Adjustment for body mass index did not substantially affect the risk estimates. Stratification by subtype indicated significant associations with IL-10 and leptin for follicular but not for diffuse large B-cell lymphoma. Excluding cases diagnosed less than 1 year after phlebotomy attenuated all associations.

CONCLUSIONS

IL-10 was the only cytokine and leptin the only adipokine associated with NHL, but due to the short follow-up time, preclinical effects cannot be excluded.

IMPACT

Although markers of inflammation and adiposity may provide new insights into the etiology of NHL, they need to be assessed many years before clinical diagnosis.

Lymphocytes in obesity-related adipose tissue inflammation

Inflammation in the white adipose tissue (WAT) is considered a major player in the development of insulin resistance. The role of macrophages accumulating in the WAT during obesity, promoting WAT inflammation and insulin resistance is well established. In contrast, less is known about the role of lymphocytes. Recent studies have implicated different lymphocyte subsets in WAT inflammation. For instance, cytotoxic CD8(+) T cells infiltrating the WAT may contribute to the recruitment, differentiation and activation of macrophages. On the other hand, a differential role for CD4(+) Th1 and CD4(+) Th2 cells has been suggested. Levels of WAT regulatory T cells decrease during the course of obesity and may represent a crucial factor for the maintenance of insulin sensitivity. Moreover, activation of natural killer T cells, an innate-like T cell population, which recognises lipid antigens, promotes insulin resistance and WAT inflammation. Finally, B cells may infiltrate WAT very early in response to high-fat feeding and worsen glucose metabolism through modulation of T cells and the production of pathogenic antibodies. These interesting new findings however bear controversies and introduce novel, yet unanswered, questions. Here, we review and discuss the impact of the different lymphocyte subsets in obesity-related WAT inflammation and attempt to identify the open questions to be answered by future studies.

Endocrine problems in children with Prader-Willi syndrome: special review on associated genetic aspects and early growth hormone treatment

Prader-Willi syndrome (PWS) is a complex multisystem genetic disorder characterized by hypothalamic-pituitary dysfunction. The main clinical features include neonatal hypotonia, distinctive facial features, overall developmental delay, and poor growth in infancy, followed by overeating with severe obesity, short stature, and hypogonadism later in development. This paper reviews recent updates regarding the genetic aspects of this disorder. Three mechanisms (paternal deletion, maternal disomy, and deficient imprinting) are recognized. Maternal disomy can arise because of 4 possible mechanisms: trisomy rescue (TR), gamete complementation (GC), monosomy rescue (MR), and postfertilization mitotic nondisjunction (Mit). Recently, TR/GC caused by nondisjunction at maternal meiosis 1 has been identified increasingly, as a result of advanced maternal childbearing age in Korea. We verified that the d3 allele increases the responsiveness of the growth hormone (GH) receptor to endogenous GH. This paper also provides an overview of endocrine dysfunctions in children with PWS, including GH deficiency, obesity, sexual development, hypothyroidism, and adrenal insufficiency, as well as the effects of GH treatment. GH treatment coupled with a strictly controlled diet during early childhood may help to reduce obesity, improve neurodevelopment, and increase muscle mass. A more active approach to correct these hormone deficiencies would benefit patients with PWS.

Adiponectin receptor signalling in the brain

Adiponectin is an important adipocyte-derived hormone that regulates metabolism of lipids and glucose, and its receptors (AdipoR1, AdipoR2, T-cadherin) appear to exert actions in peripheral tissues by activating the AMP-activated protein kinase, p38-MAPK, PPARα and NF-kappa B. Adiponectin has been shown to exert a wide range of biological functions that could elicit different effects, depending on the target organ and the biological milieu. There is substantial evidence to suggest that adiponectin receptors are expressed widely in the brain. Their expression has been detected in regions of the mouse hypothalamus, brainstem, cortical neurons and endothelial cells, as well as in whole brain and pituitary extracts. While there is now considerable evidence for the presence of adiponectin and its receptors in the brain, their precise roles in brain diseases still remain unclear. Only a few research studies have looked at this facet of adiponectins in brain disorders. This brief review will describe the evidence for important functions by adiponectin, its structure and known actions, evidence for expression of AdipoRs in the brain, their involvement in brain disorders and the therapeutic potential of agents that could modify AdipoR signalling.

Apoptosis and inflammation: role of adipokines in inflammatory bowel disease

OBJECTIVES

Leptin and adiponectin (APN) are adipokines produced by adipocytes that participate in the modulation of immune and inflammatory responses. In Crohn's disease (CD), fat wrapping surrounding the inflamed intestine produces high levels of leptin and APN. In inflammatory bowel disease (IBD), apoptosis resistance of lamina propria T lymphocytes (LPL-T) is one of the mechanisms that maintains chronic inflammation. We addressed the mechanism by which leptin and APN regulate inflammation and apoptosis in IBD.

METHODS

Immune cell infiltration, several factors expressed by adipose tissue (AT), and spontaneous release of cytokines by adipocytes were measured. The presence of APN and leptin in intestinal mucosa was detected and their effect on LPL-T apoptosis, signal transducer and activator of transcription 3 (STAT3), Suppressor of Cytokine Signaling 3 (SOCS3), Bcl-2 and Bcl-xL expression, and cytokine production was studied. In addition, the effects of globular and high-molecular-weight (HMW) APN on LPL-T cytokine production and apoptosis were studied.

RESULTS

Higher levels of several chemokines, cytokines, and growth factors were present in AT near active than near inactive disease. A significantly higher amount of inflammatory infiltrate was present in AT near active CD than near ulcerative colitis, controls, and near the inactive area of CD. There were no changes in the ratios of APN molecular weight in control and IBD adipocyte products. Leptin and APN inhibited anti-CD3-stimulated-LPL-T apoptosis and potentiated STAT3 phosphorylation, Bcl-2, and Bcl-xL expression in IBD and control mucosa. However, SOCS3 expression was suppressed only in IBD. Both globular and HMW APN have similar effects on LPL-T cytokine production and apoptosis. Leptin and APN enhanced interleukin (IL)-10 production by anti-CD3-stimulated LPL-T in IBD only. APN, but not leptin, increased anti-CD3-induced IL-6 levels in LPL-T only in IBD patients. IL-10 exerts its anti-inflammatory activity in the presence of SOCS3 suppression by leptin or APN.

CONCLUSION

Leptin and APN maintain the inhibition of anti-CD3-stimulated LPL-T apoptosis by enhancing Bcl-2 and Bcl-xL overexpression and promoting STAT3 phosphorylation while suppressing SOCS3.

Correlation of adiponectin receptor expression with cytokines and insulin sensitivity in growth hormone (GH)-treated children with Prader-Willi syndrome and in non-GH-treated obese children

CONTEXT

Prader-Willi syndrome (PWS), a genetic disorder characterized by obesity in early childhood, is reported to have elevated levels of adiponectin. The effects of adiponectin are mediated by adiponectin receptors (ADIPORs) that include ADIPOR1 and ADIPOR2. There is evidence that several cytokines, including adiponectin, TNF-alpha, and IL-6, are involved in insulin sensitivity.

OBJECTIVE AND METHODS

We measured the relative expression of adiponectin, ADIPORs, several proinflammatory cytokines including TNF-alpha, and IL-6 expression in peripheral blood mononuclear cells (PBMCs) of children with PWS and obese comparators using real-time PCR. Their correlation with homeostasis model assessment insulin resistance index (HOMA-IR) was analyzed.

PATIENTS

Thirty children with PWS (median age 7.1 yr, 18 males, 12 females) that were being treated with GH and 32 obese children not receiving GH treatment (median age 9.1 yr, 15 males, 17 females) for comparison were enrolled.

RESULTS

The PWS children had increased expression of ADIPOR2 (P = 0.02) and decreased expression of IL-6 (P = 0.03) compared with the comparison group. Moreover, there was a significant positive correlation between the ADIPORs and TNF-alpha (ADIPOR1 vs. TNF-alpha: r = 0.66, P < 0.001 in PWS, r = 0.80, P < 0.001 in comparison group; ADIPOR2 vs. TNF-alpha: r = 0.69, P < 0.001 in comparison group). The ADIPORs in the comparison group showed significant negative correlation with HOMA-IR (ADIPOR1 vs. HOMA-IR; rho = -0.41, P = 0.02, ADIPOR2 vs. HOMA-IR; rho = -0.46, P < 0.01).

CONCLUSION

The results of this study showed that inflammatory cytokine expression was closely associated with the expression of the ADIPORs in the PBMCs of both the children with PWS and the comparison group. Moreover, ADIPOR2 expression was highly expressed in the PBMCs of the children with PWS. A further study on the mechanism of increased expression of ADIPOR2 and its correlation with the expression of TNF-alpha in the PBMCs using the non-GH-treated PWS and obese control will be warranted because this study compared GH-treated PWS with an obese comparator group.

Adipocytokines in relation to Hodgkin lymphoma in children

This case-control study aims to explore the association of serum adiponectin/leptin with childhood Hodgkin lymphoma (HL). Study participants were 75 children with histologically confirmed HL, registered in the Nationwide Registry for Childhood Haematological Malignancies and 75 age- and gender-matched controls. Multiple conditional logistic regression analyses were performed, adjusting for sociodemographic and lifestyle parameters. Adiponectin levels were consistently higher among cases in all models with ORs >1.25; 95% CIs ranging from 0.9 to 1.8 and P-values from 0.09 to 0.20. By contrast, there was no association of serum leptin with HL. In conclusion, elevated serum adiponectin might be a risk factor for childhood HL.

Asthma and obesity in childhood: on the road ahead

Epidemiological data show a link between asthma and obesity, suggesting many different mechanisms that may underlie the association. However, diagnosis of asthma is often self-reported by patients or caregivers. Definition of asthma is crucial, particularly in childhood. Obesity can be associated with symptoms commonly attributed to asthma, such as wheezing, dyspnoea and sleep apnoea. Obese subjects are less fit and may have more frequent bouts of breathlessness on exertion accompanied by an exaggerated symptom perception. Therefore, the link between the two diseases should be analysed by focusing not only on reported diagnosis of asthma but also on objective markers that can better characterize the asthma phenotype. These markers should include lung function parameters, bronchial hyper-reactivity, atopic sensitization and indices of lung inflammation. As we look back and move forward, a multidisciplinary approach is increasingly necessary to understand the complexity of obesity and asthma, keeping in mind that diet and exercise could influence both diagnosis and treatment. In the meantime, in clinical settings, physicians should be cautious about diagnosing asthma in obese children on the basis of self-reported symptoms alone and should confirm the diagnosis by using objective measurements and marker evaluations that can better identify asthma phenotype and exclude overdiagnosis.

Serum adiponectin as a predictor of childhood non-Hodgkin's lymphoma: a nationwide case-control study

PURPOSE

To our knowledge, this is the first study exploring the association of childhood non-Hodgkin's lymphoma (NHL) with serum adiponectin and leptin levels in a nationwide case-control series. In addition, expression of adiponectin receptors in NHL specimens was assessed, and the association between adipokines and childhood NHL survival and prognosis was examined.

PATIENTS AND METHODS

We studied 121 incident childhood (0 to 14 years) NHL cases registered in the Nationwide Registry for Childhood Hematological Malignancies (1996 to 2006) and an equal number of matched controls, for whom sociodemographic, lifestyle, prenatal characteristics, and fasting blood serums were collected. Serum adiponectin and leptin levels were determined. Immunohistochemisty for adiponectin receptors expression was performed on commercially available adult NHL specimens (n = 30) and in a subset of childhood NHL cases (n = 6) that were available. Summary statistics, multiple conditional logistic regression analyses, and survival analysis were performed.

RESULTS

Higher serum adiponectin, but not leptin, levels were independently associated with childhood NHL (odds ratio, 1.82; 95% CI, 1.30 to 2.56), after adjusting for obesity and established risk factors. Higher adiponectin levels at diagnosis were positively associated with relapse and poor survival, but hormone levels did not differ among NHL subtypes. Adiponectin receptors 1 and 2 were present in 90% and 57% of adult samples and in 83% and 100% of childhood NHL samples, respectively.

CONCLUSION

Elevated serum adiponectin, but not leptin, levels are independently associated with childhood NHL and poor prognosis. Adiponectin receptors are expressed in NHL, suggesting that adiponectin may represent not only a potential clinically significant diagnostic and prognostic marker but also a molecule that may be implicated in NHL pathogenesis.

Molecular cloning, gene expression, and tissue distribution of adiponectin and its receptors in the Japanese monkey, Macaca fuscata

BACKGROUND

Adiponectin is an adipocyte-derived hormone that affects regulation of metabolic syndrome such as insulin resistance, type-2 diabetes, and obesity. It functions via seven transmembrane domain receptors [i.e.,adiponectin receptors 1 (AdipoR1) and 2 (AdipoR2)] that have been scarcely investigated in non-human primates.

METHODS

Molecular cloning of cDNAs for adiponectin, AdipoR1, and AdipoR2 that included the whole protein-coding region in the Japanese monkey, Macaca fuscata, was carried out. Tissue-specific expression of respective genes was analyzed with Northern blot hybridization.

RESULTS

The essential Cys36 and four lysine residues in adiponectin, and transmembrane-spanning domains in AdipoR1 and AdipoR2 appear well conserved. While adiponectin mRNA is expressed only in adipose tissues, AdipoR1 mRNA was found to be expressed in various tissues including the brain.

CONCLUSIONS

These results significantly add to the understanding of the molecular basis of obesity-related adipokines and their receptors in nonhuman primates.

Adiponectin deficiency modulates adhesion molecules expression and cytokine production but does not affect disease severity in the transfer model of colitis

We investigated the effect of adiponectin (APN) deficiency in the CD4(+)CD45RB(high) transfer model of colitis. Recombination activating gene (Rag)-1 knockout (KO) and Rag-1 APN KO mice receiving CD4(+)CD45RB(high) cells developed colitis of comparable severity. Colonic mRNA expression of IL-6 and IL-17 was lower in Rag-1 APN KO mice compared to Rag-1 KO mice. Rag-1 APN KO and Rag-1 KO mice released comparable amounts of IL-6 from colon cultures, whereas release of IL-17 was higher in Rag-1 APN KO compared to Rag-1 KO mice. Expression of TNFalpha mRNA was comparable in Rag-1 KO and Rag-1 APN KO mice, but protein release was lower in Rag-1 APN KO mice compared to Rag-1 KO mice. Levels of IFNgamma and IL-10 at mRNA and protein were comparable in Rag-1 KO and Rag-1 APN KO mice. Higher mRNA expression of VCAM-1 was observed in the colon of healthy APN KO compared to WT mice, while induction of colitis resulted in a comparable increase in VCAM-1 expression in Rag-1 KO and Rag-1 APN KO mice. In conclusion, although APN regulates expression of cytokines and adhesion molecules in the colon, this does not result in alteration of overall colitis severity in the CD4(+)CD45RB(high) transfer model.

Reduced response to adiponectin and lower abundance of adiponectin receptor proteins in type 2 diabetic monocytes

The abundance of the adiponectin receptors, AdipoR1 and AdipoR2, and the effects of the antidiabetic adipokine adiponectin in monocytes of normal-weight and overweight controls and type 2 diabetic patients (T2D) were analyzed. AdipoR1 and AdipoR2 mRNAs were increased in monocytes of obese controls and T2D patients when compared to normal-weight controls, and AdipoR1 mRNA positively correlated to AdipoR2 mRNA, the waist to hip ratio and systemic adiponectin. However, AdipoR1 and AdipoR2 proteins were lower in monocytes of T2D compared to normal-weight donors. Induction of IL-6 and IL-8 by adiponectin, an effect involving p38 MAPK, was also reduced in T2D monocytes.

Obesity and asthma: possible mechanisms

Epidemiologic data indicate that obesity increases the prevalence and incidence of asthma and reduces asthma control. Obese mice exhibit innate airway hyperresponsiveness and augmented responses to certain asthma triggers, further supporting a relationship between obesity and asthma. Here I discuss several mechanisms that may explain this relationship. In obesity, lung volume and tidal volume are reduced, events that promote airway narrowing. Obesity also leads to a state of low-grade systemic inflammation that may act on the lung to exacerbate asthma. Obesity-related changes in adipose-derived hormones, including leptin and adiponectin, may participate in these events. Comorbidities of obesity, such as dyslipidemia, gastroesophageal reflux, sleep-disordered breathing, type 2 diabetes, or hypertension may provoke or worsen asthma. Finally, obesity and asthma may share a common etiology, such as common genetics, common in utero conditions, or common predisposing dietary factors. Novel therapeutic strategies for treatment of the obese patient with asthma may result from an increased understanding of the mechanisms underlying this relationship.