leptin and Hypersensitivity

Both allergic disorders and obesity keep increasing in industrialized countries. Even though a strong association between obesity and allergy- related diseases has been reported in several studies, no published data show a scientific and firm link in-between the two conditions. In general, obesity and weight gain have been associated with an increased risk of asthma and allergic rhinitis. Asthma, allergic rhinitis and obesity have a common inflammatory pattern that could therefore justify their association. In fact, the chronic inflammation that characterizes the increase in white adipose tissue typically pushes the immune system toward a Th2 pattern. Such a polarization might, consequentially, worsen a pre-existing allergic disease or even stimulate the evolution from a sensitization to a respiratory form of allergy. Several studies have been published on the role of different adipokines on allergic diseases. We focus our review on the role of adipokines on asthma and allergic rhinitis.

Topics: Adipokines; Adiponectin; Asthma; Child; Humans; Hypersensitivity; Leptin; Rhinitis, Allergic, Seasonal

Asthma patients with comorbid obesity exhibit increased disease severity, in part, due to airway remodeling, which is also observed in mouse models of asthma and obesity. A mediator of remodeling that is increased in obesity is leptin. We hypothesized that in a mouse model of allergic airways disease, mice receiving exogenous leptin would display increased airway inflammation and fibrosis.. Five-week-old male and female C57BL/6J mice were challenged with intranasal house dust mite (HDM) allergen or saline 5 days per week for 6 weeks (n = 6-9 per sex, per group). Following each HDM exposure, mice received subcutaneous recombinant human leptin or saline. At 48 h after the final HDM challenge, lung mechanics were evaluated and the mice were sacrificed. Bronchoalveolar lavage was performed and differential cell counts were determined. Lung tissue was stained with Masson's trichrome, periodic acid-Schiff, and hematoxylin and eosin stains. Mouse lung fibroblasts were cultured, and whole lung mRNA was isolated.. Leptin did not affect mouse body weight, but HDM+leptin increased baseline blood glucose. In mixed-sex groups, leptin increased mouse lung fibroblast invasiveness and increased lung Col1a1 mRNA expression. Total lung resistance and tissue damping were increased with HDM+leptin treatment, but not leptin or HDM alone. Female mice exhibited enhanced airway responsiveness to methacholine with HDM+leptin treatment, while leptin alone decreased total respiratory system resistance in male mice.. In HDM-induced allergic airways disease, administration of exogenous leptin to mice enhanced lung resistance and increased markers of fibrosis, with differing effects between males and females.

Topics: Allergens; Animals; Asthma; Biomarkers; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Female; Fibrosis; Humans; Hypersensitivity; Leptin; Lung; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Obesity; Pulmonary Disease, Chronic Obstructive; Pulmonary Fibrosis; Pyroglyphidae; RNA, Messenger

Liver function abnormalities are common in patients with inflammatory arthritis. However, the precise mechanism is still unclear. In this study, inflammatory arthritis was established in mice by subcutaneous injection of complete Freund's adjuvant, and the intravenous injection of concanavalin A (Con A) was employed to induce acute immune-mediated hepatitis in mice. The result showed that the arthritis mice were more susceptible to ConA-induced hepatitis than the control mice, as evidenced by increased hepatic necrosis, elevated serum alanine aminotransferase activity, and raised inflammatory cytokines. Besides, the in vitro assay demonstrated that the T cells from arthritis mice were more sensitive to the Con A stimulation than those from control mice. Moreover, we determined that the level of leptin, a kind of adipokine, was significantly increased in the serum and hepatic T cells of arthritis mice. Interestingly, the data indicated that the enhanced expression of leptin in hepatic T cells is responsible for the hypersensitivity of arthritis mice-derived T cells to Con A challenge. Collectively, our findings demonstrate an unexpected role of leptin in the connection between inflammatory arthritis and acute immune-mediated hepatitis, thus providing new insight into the clinical therapy of arthritis-related liver dysfunction.

Topics: Acute Disease; Animals; Arthritis; Concanavalin A; Cytokines; Disease Susceptibility; Hepatitis; Hypersensitivity; Inflammation; Inflammation Mediators; Leptin; Liver; Lymphocyte Activation; Mice, Inbred C57BL; Signal Transduction; T-Lymphocytes

Adipose tissue is a major source of circulating exosomal microRNAs (miRNAs) that are modulators of the immune response in various types of tissues and organs, including airways. Still, no evidence exists if allergic airway inflammation may affect fat tissue inflammation via alterations in the miRNA expression profile. Therefore, we investigated the miRNA expression profile in the adipose tissue upon induced allergic inflammation in the airways in the rat. Brown Norway rats were chronically sensitized to house dust mite extract for seven weeks. Body composition was performed using MiniSpec Plus. The eosinophil count and the total IgE level were determined to confirm the induction of allergic inflammation. MiRNA expression profiling was done using the next-generation sequencing with validation by qPCR. We found that allergic airway inflammation significantly increased fat in adipose tissue, glucose concentration, and the gene expression of adipose tissue-derived proinflammatory peptides (leptin, TNFα). In miRNA-seq analysis, we showed significant differences in the expression of 36 mature miRNAs, three precursors, and two miRNA families in adipose tissue of allergic rats. Two miRNAs-miRNA-151-5p and miRNA-423-3p-showed significantly increased expression in qPCR in adipose tissue and lungs of sensitized animals. Allergic airway inflammation affects fat tissue and alters miRNA expression profile in adipose tissue in the rat.

Topics: Adipose Tissue; Animals; Gene Expression; Gene Expression Profiling; High-Throughput Nucleotide Sequencing; Hypersensitivity; Immunoglobulin E; Inflammation; Leptin; Lung; Male; MicroRNAs; Rats; Rats, Inbred BN; Transcriptome

Topics: Adult; Asthma; Calcitriol; CD4-Positive T-Lymphocytes; Cytokines; Female; Humans; Hypersensitivity; Immunoglobulin E; In Vitro Techniques; Interleukin-10; Interleukin-17; Interleukin-5; Interleukin-6; Leptin; Male; Middle Aged; Obesity; Severity of Illness Index; Th1 Cells; Th17 Cells; Vitamin D; Vitamins; Young Adult

Arachidonic acid (AA) is considered essential in fetal development and some of its metabolites are thought to be important mediators of the immune responses. Therefore, we studied whether prenatal exposure to AA is associated with some immune-related clinical conditions and plasma markers in childhood. In 280 children aged 7 years, atopy, lung function and plasma inflammation markers were measured and their relationships with early AA exposure were studied by linear and logistic regression analyses. AA exposure was deduced from AA concentrations in plasma phospholipids of the mothers collected at several time points during pregnancy and at delivery, and in umbilical cord plasma and arterial and venous wall phospholipids. In unadjusted regression analyses, significant positive associations were observed between maternal AA concentrations at 16 and 32 weeks of pregnancy (proxies for fetal AA exposure) and peak expiratory flow decline after maximal physical exercise and plasma fibrinogen concentrations of their children, respectively. However, after correction for relevant covariables, only trends remained. A significant negative relationship was observed between AA concentrations in cord plasma (reflecting prenatal AA exposure) and the average daily amplitude of peak expiratory flow at rest, which lost significance after appropriate adjustment. Because of these few, weak and inconsistent relationships, a major impact of early-life exposure to AA on atopy, lung function and selected plasma inflammation markers of children at 7 years of age seems unlikely.

Topics: Arachidonic Acid; Asthma; Biomarkers; C-Reactive Protein; Child; Child Development; Female; Fetal Blood; Fibrinogen; Follow-Up Studies; Humans; Hypersensitivity; Infant, Newborn; Leptin; Linear Models; Peak Expiratory Flow Rate; Pregnancy; Pregnancy Trimester, Second; Pregnancy Trimester, Third; Prenatal Exposure Delayed Effects; Prospective Studies; Respiratory Function Tests; von Willebrand Factor

Topics: Adipokines; Animals; Child; Fatty Acids; Humans; Hypersensitivity; Immunoglobulin E; Leptin; Obesity

Obesity and respiratory allergies have increased in parallel in industrialized countries. We have recently shown an association between obesity and allergic sensitization whereby obesity diminished the protective effect of childhood farm contact.. To assess whether taking obesity into account allergic sensitization is associated with adipokine levels in blood and whether this effect is modified by childhood farm contact.. Serum samples of 231 adult participants (age 18-45 years) of the Lower Saxony Lung Study were analysed for leptin and adiponectin by ELISA. Subjects were elected to represent equal-sized groups with respect to obesity (<30 vs> or =30 kg/m(2)), childhood farm contact, specific IgE to ubiquitous allergens and sex. Multiple logistic regression models were adjusted for potential confounders.. Leptin levels were positively related to the prevalence of sensitization (highest vs lowest quartile odds ratio 6.7, 95% confidence interval 2.0-22.4). For adiponectin levels, a weak, not statistically significant inverse association with sensitization was shown (highest vs lowest quartile 0.4, 0.2-1.1). The association between leptin and sensitization appeared to be more pronounced in subjects with farm contact; however, the effect modification was not statistically significant.. These findings suggest that adipokines might be involved in the causal pathway between obesity and allergic sensitization.

Topics: Adiponectin; Adolescent; Adult; Allergens; Female; Humans; Hypersensitivity; Leptin; Logistic Models; Male; Middle Aged; Obesity; Surveys and Questionnaires; Young Adult

Leptin is a pleiotropic adipocyte-derived cytokine used in hypothalamic regulation of body weight and modulation of immune response by stimulating T cells, macrophages and neutrophils. Leptin has been shown to be an eosinophil survival factor. We examined the immunopathological mechanisms for the activation of human eosinophils from healthy volunteers by leptin in allergic inflammation. Adhesion molecules, cytokines and cell migration were assessed by flow cytometry, ELISA and Boyden chamber assay, respectively. Intracellular signaling molecules were investigated by membrane array and Western blot. Leptin could up-regulate cell surface expression of adhesion molecule ICAM-1 and CD18 but suppress ICAM-3 and L-selectin on eosinophils. Leptin could also stimulate the chemokinesis of eosinophils, and induce the release of inflammatory cytokines IL-1beta and IL-6, and chemokines IL-8, growth-related oncogene-alpha and MCP-1. We found that leptin-mediated induction of adhesion molecules, release of cytokines and chemokines, and chemokinesis were differentially regulated by the activation of ERK, p38 MAPK and NF-kappaB. In view of the above results and elevated production of leptin in patients with allergic diseases such as atopic asthma and atopic dermatitis, leptin could play crucial immunopathophysiological roles in allergic inflammation by activation of eosinophils via differential intracellular signaling cascades.

Topics: Blotting, Western; Cell Adhesion Molecules; Chemotaxis, Leukocyte; Cytokines; Enzyme Activation; Enzyme-Linked Immunosorbent Assay; Eosinophils; Extracellular Signal-Regulated MAP Kinases; Flow Cytometry; Humans; Hypersensitivity; Inflammation; Leptin; NF-kappa B; p38 Mitogen-Activated Protein Kinases

Topics: Asthma; Child; Female; Ghrelin; Humans; Hypersensitivity; Immunoglobulin E; Leptin; Male; Obesity; Peptide Hormones

Allergic disorders, including asthma, have increased dramatically in the United States in the past 20 y. Epidemiologic studies have found body mass index (body weight in kg/height squared in m) to be a positive independent correlate of atopy in women but not in men.. We investigated the prevalence of atopy among healthy obese and nonobese women and its relation to fat mass (FM), insulin resistance, and plasma concentrations of 17beta-estradiol, interleukin 4 (IL-4), and leptin.. A cross-sectional study of 21 obese (> or = 30% body fat) and 22 nonobese (< 30% body fat) women (18-41 y of age) was performed. The following measurements were taken: FM by plethysmography, total and specific immunoglobulin E (IgE) by automated immunosorbent analysis, and blood glucose, insulin, C-peptide, 17beta-estradiol, sex hormone-binding globulin, and IL-4. Insulin sensitivity was determined on the basis of the fasting insulin resistance index and with an oral-glucose-tolerance test.. The frequency of specific IgE in the obese group was almost 3 times that in the nonobese group (P = 0.008). The total IgE concentration was not significantly different between groups. Plasma concentrations of 17beta-estradiol, the ratio of 17beta-estradiol to sex hormone-binding globulin, the fasting insulin resistance index, and C-peptide and leptin concentrations were higher in the obese than in the nonobese group (P < 0.05) after adjustment for oral contraceptive use. All factors correlated positively with FM. Logistic regression showed FM to be the only positive predictor of specific IgE (P = 0.01).. The findings confirm a direct relation between obesity and a T helper 2 cell immune response in women.

Topics: Adipose Tissue; Adolescent; Adult; Case-Control Studies; Cross-Sectional Studies; Estradiol; Female; Glucose Tolerance Test; Humans; Hypersensitivity; Immunoglobulin E; Insulin Resistance; Interleukin-4; Leptin; Logistic Models; Obesity; Prevalence; Sex Factors; Sex Hormone-Binding Globulin

Leptin is important for maintenance of the body's energy homeostasis and it also increases Th1 and suppresses Th2 cytokine production. We have investigated the effect of leptin on the allergic immune response to the model allergen ovalbumin (OA) by using the popliteal lymph node assay (PLNA) and serum antibody determination in mice. Mice were injected with either leptin i.v. plus OA in one hind footpad, or leptin or OA alone. A booster dose of leptin was given twice and of OA once and the animals were exsanguinated on experimental day 19 when the PLNs also were removed. End-point measurements were serum levels of IgE, IgG1, and IgG2a anti-OA and weight and cell number of the excised PLNs. Leptin given i.v. with the protocol employed altered neither the cellular PLN response nor the specific serum IgE, IgG1, or IgG2a anti-OA levels compared with the group given OA without leptin. Our data indicate that systemic administration of leptin neither suppresses nor enhances the Th2-dependent antibody responses in the present mouse model.

Topics: Allergens; Animals; Cells, Cultured; Hypersensitivity; Immunoglobulin E; Immunoglobulin G; Inflammation; Leptin; Lymph Nodes; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Ovalbumin; Th1 Cells; Th2 Cells