Metformin attenuates the exacerbation of the allergic eosinophilic inflammation in high fat-diet-induced obesity in mice

A positive relationship between obesity and asthma has been well documented. The AMP-activated protein kinase (AMPK) activator metformin reverses obesity-associated insulin resistance (IR) and inhibits different types of inflammatory responses. This study aimed to evaluate the effects of metformin on the exacerbation of allergic eosinophilic inflammation in obese mice. Male C57BL6/J mice were fed for 10 weeks with high-fat diet (HFD) to induce obesity. The cell infiltration and inflammatory markers in bronchoalveolar lavage (BAL) fluid and lung tissue were evaluated at 48 h after ovalbumin (OVA) challenge. HFD obese mice displayed peripheral IR that was fully reversed by metformin (300 mg/kg/day, two weeks). OVA-challenge resulted in higher influx of total cell and eosinophils in lung tissue of obese mice compared with lean group. As opposed, the cell number in BAL fluid of obese mice was reduced compared with lean group. Metformin significantly reduced the tissue eosinophil infiltration and prevented the reduction of cell counts in BAL fluid. In obese mice, greater levels of eotaxin, TNF-α and NOx, together with increased iNOS protein expression were observed, all of which were normalized by metformin. In addition, metformin nearly abrogated the binding of NF-κB subunit p65 to the iNOS promoter gene in lung tissue of obese mice. Lower levels of phosphorylated AMPK and its downstream target acetyl CoA carboxylase (ACC) were found in lung tissue of obese mice, which were restored by metformin. In separate experiments, the selective iNOS inhibitor aminoguanidine (20 mg/kg, 3 weeks) and the anti-TNF-α mAb (2 mg/kg) significantly attenuated the aggravation of eosinophilic inflammation in obese mice. In conclusion, metformin inhibits the TNF-α-induced inflammatory signaling and NF-κB-mediated iNOS expression in lung tissue of obese mice. Metformin may be a good pharmacological strategy to control the asthma exacerbation in obese individuals.Fundação de Amparo à Pesquisa do Estado de São Paulo, 2012/14225-

Influence of obesity on allergic asthma development

Orientador: Edson AntunesTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências MédicasResumo: A obesidade e a asma são doenças prevalentes e crescentes, e ambas têm impacto significativo na saúde pública mundial. O aumento simultâneo da prevalência da asma e da obesidade tem levado investigadores a sugerir que a obesidade possa ser um fator importante no desenvolvimento da asma, ou até piorar um quadro de asma pré-existente. Numerosos estudos populacionais conduzidos em todo o mundo indicam que a prevalência de asma é maior em indivíduos obesos versus magros. Além disso, diversos estudos prospectivos, tanto em adultos quanto em crianças, indicam que o risco relativo da incidência de asma aumenta com o índice de massa corporal (IMC). A obesidade também piora o controle medicamentoso da asma e a gravidade desta doença. Recentemente, diversos dados emergiram indicando que a inflamação associada à obesidade pode aumentar a propensão para o desenvolvimento de asma. Acredita-se que a resistência à insulina associada à obesidade desempenha importante papel no desenvolvimento da asma, explicando, ao menos em parte, a associação da asma com obesidade. Relatos recentes indicam uma alta prevalência de resistência à insulina em pacientes obesos e asmáticos versus obesos não asmáticos, sugerindo que a resistência à insulina possa contribuir com este fenótipo. Baseado nestas informações, o objetivo deste trabalho foi verificar se doenças metabólicas associadas à obesidade, tal como a resistência à insulina, podem estar envolvidas na exacerbação da asma associada à obesidade. No presente estudo observamos que o tratamento de camundongos obesos com metformina corrige a resistência à ação sistêmica da insulina. Além disso, metformina normaliza o trânsito dos eosinófilos da medula óssea até o lúmen em animais obesos e desafiados com OVA. Essa normalização parece ser mediada pela ativação da AMPK no pulmão e diminuição das concentrações de TNF-? e NOx no LBA e inibição da expressão de iNOS induzida pelo fator de transcrição NF-?B no pulmão. Além disso, ao normalizar o tráfego de eosinófilos da região peribronquiolar para a luz das vias aéreas, o tratamento com metformina induz concomitante diminuição do acúmulo de eosinófilos na medula óssea devido à regulação positiva da expressão de moléculas de adesão VLA-4 e Mac-1 na superfície das células e posterior aumento da resposta adesiva à ICAM-1 e VCAM-1. Os resultados descritos neste estudo parecem confirmar a hipótese que a resistência à insulina, resultante da obesidade, medeia a exacerbação da resposta inflamatória pulmonar observada em animais obesos. Dessa forma, ao corrigir a resistência à insulina sistêmica através da ativação da AMPK, camundongos sensibilizados obesos aceleram o início do processo de resolução da inflamação pulmonar alérgicaAbstract: Obesity and asthma are prevalent and increasing diseases, and both have significant impact on global public health. The increase in prevalence of asthma and obesity has led researchers to suggest that obesity may be an important factor in the development of asthma, or even worse the pre-existing asthma. Numerous populational studies conducted around the world indicate that the prevalence of asthma is higher in obese versus lean person. In addition, several prospective studies, both in adults and in children, indicate that the relative risk of incident asthma increases with body mass index (BMI). Obesity also worsens the drug therapy of asthma and the severity of this disease. Recently, several data emerged showing that the inflammation associated with obesity increase the propensity for development of asthma. It is believed that insulin resistance associated with obesity plays an important role in the development of asthma, explaining, at least in part, asthma associated with obesity. Recent reports indicate a high prevalence of insulin resistance in obese asthmatics versus obese non-asthmatics patients, suggesting that insulin resistance may contribute to this phenotype. Based on this information, the purpose of this study was to determine whether metabolic diseases associated with obesity such as insulin resistance, are involved in asthma exacerbation associated with obesity. In the present study we observed that obese mice treated with metformin, impairs the resistantance to the systemic action of insulin. Furthermore, in obese mice challend with OVA, metformin normalizes the transit of eosinophils from bone marrow to the lung lumen. This normalization is mediated by AMPK activation in the lung, as well as decreased concentrations of TNF-? and nitrite and nitrate in BAL fluid accompanied by the inhibition of NF-?B induced iNOS expression in the lung. Furthermore, by normalizing the eosinophils trafficking from peribronchiolar region to airway lumen, metformin treatment induces concomitant reduction in the accumulation of eosinophils in bone marrow through the upregulation of adhesion molecules VLA-4 and Mac-1 on cell surface and subsequent increase in the adhesive response to plates coated with ICAM-1 and VCAM-1. Our data seem to confirm the hypothesis that insulin resistance resulting from obesity mediates the exacerbation of airway inflammation in high fat-diet mice. Thus, by normalizing the systemic insulin resistance through the atictivation of AMPK, obese sensitized mice progress to resolution of allergic airway inflammationDoutoradoFarmacologiaDoutora em Farmacologi

Influence of obesity on allergic asthma development

Orientador: Edson AntunesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências MédicasResumo: O aumento no número de eosinófilos (EO) nos tecidos, sangue e medula óssea (MO) são considerados eventos importantes na asma, e em geral, números elevados destas células estão correlacionados com a gravidade da doença. Dados epidemiológicos indicam que a obesidade aumenta a prevalência e incidência de asma alérgica e reduz seu controle. Acredita-se que a obesidade e a asma apresentam algumas etiologias comuns, principal-mente em suas bases genética. Entretanto, é possível que existam outros mecanismos bioló-gicos através dos quais a obesidade pode ser tanto a responsável pela causa como pelo a-gravamento da asma. O aumento do tecido adiposo parece elevar a produção de citocinas e quimiocinas, tais como IL-6, TNF-? e eotaxina. Camundongos geneticamente obesos apre-sentam hiperreatividade inata das vias aeríferas, porém pouca atenção tem sido dada ao recrutamento pulmonar de EO em animais obesos. Uma vez que o acúmulo seletivo de eo-sinófilos para as vias aeríferas é considerado um evento central na patogênese da asma, este estudo teve como objetivo investigar o influxo de eosinófilos para o pulmão e o papel das citocinas Th1 e Th2 neste processo, em camundongos obesos por indução de dieta. Foram utilizados camundongos C57bl6/J que receberam dieta hiperlipídica por dez semanas. Na oitava semana de tratamento, os animais foram sensibilizados com 2 injeções s.c de oval-bumina (OVA) com intervalo de sete dias entre as mesmas. Na semana seguinte, camun-dongos sensibilizados e não sensibilizados foram desafiados por via intranasal com OVA. Os camundongos foram sacrificados em diferentes tempos (24, 48, 72 e 96 h) após o desa-fio com OVA, e a contagem de EO no sangue, lavado broncoalveolar (LBA) e MO foi ava-liada. Camundongos obesos por indução de dieta hiperlipídica exibiram aumento no ganho de peso ponderal e no peso do tecido adiposo epididimal, bem como aumento nos níveis de colesterol total comparados com camundongos controle. O desafio intranasal com OVA em camundongos sensibilizados aumentou significativamente a contagem de EO no LBA em todos os tempos avaliados após o desafio com OVA. O número de eosinófilos foi pratica-mente nulo em camundongos não sensibilizados. Camundongos sensibilizados obesos apre-sentaram uma migração tardia de EO para O LBA, com pico em 72 h após o desafio. Além disso, a análise morfológica demonstrou que o parênquima pulmonar de camundongos sen-sibilizados obesos apresentam um marcante aumento no infiltrado de EO, tanto em 48 quanto em 72 h após o desafio, quando comparado com camundongos sensibilizados con-troles. Na MO foi encontrado um significativo aumento no número de eosinófilos maduros e imaturos nos animais sensibilizados obesos quando comparados com os sensibilizados controles. Os níveis de IL-4, IL-5, TNF-?, IL-6, IL-10 e eotaxina aumentaram significati-vamente nos camundongos obesos sensibilizados, atingindo o pico 72 h após o desafio com OVA. Nossos dados indicam que foi possível estabelecer um modelo de obesidade em ca-mundongos que claramente aumenta o influxo de EO para o pulmão em resposta ao desafio com OVA. Em camundongos obesos, os EO permaneceram retidos no parênquima pulmonar, exercendo suas funções efetoras favorecendo a patogênese da asmaAbstract; : Increases in eosinophil (EO) numbers in the tissues, blood, and bone marrow (BM) are a hallmark of asthma and, in general, elevated numbers correlate with disease severity. Epi-demiological data indicate that obesity increases the prevalence and incidence of allergic asthma. The basis for this relationship is unknown, but might be the result of common eti-ologies, comorbidities or genetic basis. Increased fat mass, particularly with central obesity, leads to production of cytokines and chemokines, such as IL-6, TNF-? and eotaxin. Studies have shown that genetically obese mice exhibit innate airway hyperresponsiveness, but little attention has been given to the allergic pulmonary EO recruitment in obese animals. Since selective accumulation of eosinophils into the airways has become a central concept of the asthma pathology, this study was designed to investigate the eosinophil influx into lungs and the role of Th2 cytokines in diet-induced obese mice. Four-week-old male C57bl6/J mice received a high fat diet for 10 weeks. On the eighth week, mice were sensi-tized with two s.c. ovalbumin (OVA) injections at 7 day intervals. One week thereafter, sensitized and non-sensitized animals were intranasally challenged with OVA. The mice were killed at different times (24, 48, 72 and 96 h) after OVA challenge, and EO counts in blood, bronchoalveolar lavage fluid (BAL) and BM were evaluated. High-fat diet mice ex-hibited a significant increase in body weight and epididymal fat, as well as increased total serum cholesterol levels compared with non-obese groups. Intranasal challenge with OVA in sensitized mice largely increased the EO counts in BAL at 48 h and 72 h post-OVA chal-lenge. Eosinophils were nearly absent in the non-sensitized mice. The sensitized obese mice showed a delayed EO emigration to BAL, peaking at 72 h post-OVA challenge. In addition, the morphological analysis showed that lung parenchyma of sensitized obese mice pre-sented a markedly higher EO infiltration at both 48 h and 72 h post-OVA challenge when compared with non-obese mice. In BM, a significant increase in counts of both mature and immature EO was also found in sensitized obese compared with sensitized non-obese mice. The levels of IL-4, IL-5, TNF-?, IL-6, IL-10 and eotaxin significantly increased in BAL of sensitized obese mice, peaking at 72 h-post OVA challenge. Our findings indicate that we have established an experimental model in C57bl6/J obese mice that clearly show a potentiation of EO influx in response to OVA challenge. In obese mice, EO are likely to be retained in the lung parenchyma exerting their effector functions in promoting the pathoge-nesis of airways diseasesMestradoMestre em Farmacologi

Characterization Of Pulmonary And Systemic Inflammatory Responses Produced By Lung Re-expansion After One-lung Ventilation.

To characterize the pulmonary and systemic inflammatory responses of rats undergoing 1-hour or 3-hour one-lung ventilation (OLV) with subsequent 1-hour lung re-expansion. A prospective, randomized, controlled animal experiment. University laboratory. Thirty male Wistar rats were used. Rats were subjected to 1- or 3-hour OLV followed or not by 1-hour lung re-expansion. Control rats received no ventilation. Pulmonary protein extravasation, pulmonary myeloperoxidase (MPO) activity, cytokine levels in serum and bronchoalveolar lavage (BAL), counts of total and differential cells in BAL fluid, gasometric data, and mean arterial blood pressure (MABP) were all evaluated. Bronchial occlusion for 1 or 3 hours with no lung re-expansion did not significantly change the protein extravasation in the right and left lungs compared with the control group. However, rats submitted to 1- or 3-hour OLV followed by lung re-expansion exhibited pulmonary edema formation and neutrophil recruitment as well as a higher MPO activity in comparison with control rats. Increased levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor-α in BAL fluid were observed. Increased levels of IL-6 and IL-10 in serum also were detected. Blood gas and MABP did not differ between groups. Lung re-expansion after bronchial occlusion evokes an acute lung inflammatory response, which has been shown to be more pronounced in long periods of bronchial occlusion in terms of cytokine inflammatory response. In addition, the magnitude of this inflammatory response also can be detected systemically.26427-3

Therapy with resveratrol attenuates obesity-associated allergic airway inflammation in mice

Obesity and insulin resistance have been associated with deterioration in asthma outcomes. High oxidative stress and deficient activation of AMP-activated protein kinase (AMPIC) have emerged as important regulators linking insulin resistance and inflammation. This study aimed to evaluate the effects of resveratrol on obesity-associated allergic pulmonary inflammation. Male C57/B16 mice fed with high-fat diet to induce obesity (obese group) or standard-chow diet (lean group) were treated or not with resveratrol (100 mg/kg/day, two weeks). Mice were sensitized and challenged with ovalbumin (OVA). At 48 h thereafter, bronchoalveolar lavage fluid was performed, and lungs collected for morphological studies and Western blot analysis. Treatment of obese mice with resveratrol significantly reduced hyperglycemia and insulin resistance, as well as the body measures (body mass, fat mass, % fat, and body area). OVA-challenge promoted a higher increase in pulmonary eosinophil infiltration in obese compared with lean mice, which was nearly abrogated by resveratrol treatment. Resveratrol markedly increased the phosphorylated AMPIC expression in lung tissues of obese compared with lean mice. Resveratrol reduced the p47phox expression and reactive-oxygen species (ROS) production, and elevated the superoxide dismutase (SOD) levels in lung tissues of obese mice. The increased pulmonary levels of TNF-alpha and inducible nitric oxide synthase (iNOS) in obese mice were also normalized after resveratrol treatment. In lean mice, resveratrol failed to affect the levels of fasting glucose, p47phox, ROS levels, TNF-alpha, iNOS and phosphorylated AMPIC. Resveratrol exhibits protective effects in obesity-associated lung inflammation that is accompanied by local AMPIC activation and antioxidant property38298305FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ – CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2014/02130-1sem informaçã

Effect of metformin treatment (300 mg/kg/day, two weeks) on the number of total inflammatory cells (A) and eosinophils (B) in bronchoalveolar lavage (BAL) fluid at 48 h following intranasal challenge with ovalbumin in sensitized mice.

<p>Each column represents the mean ± SEM (n = 10) for mice sensitized lean treated with vehicle (SL), sensitized obese treated with vehicle (SO), sensitized lean treated with metformin (SL + Met) and sensitized obese treated with metformin (SO + Met). *p<0.05.</p

Effect of aminoguanidine (20mg/kg) on glucose decay rate (K_itt; %/min) (A), number of eosinophils in the lung connective tissue surrounding the bronchial and bronchiolar segments (B) and bronchoalveolar lavage (BAL) fluid (C) at 48 h following intranasal challenge with ovalbumin in sensitized mice.

<p>Representative high-power fields of bronchiolar structures from the following groups: mice sensitized lean treated with vehicle (SL), sensitized obese treated with vehicle (SO), sensitized lean treated with amoniguanidine (SL + Aminog) and sensitized obese treated with amoniguanidine (SO + Aminog). Panel D shows representative images of lung histology for the four experimental groups. Haematoxylin–eosin, high magnification (bar represents 20 µm). Each column represents mean ± SEM (n = 6). * p<0.05.</p

Effect of metformin treatment on body weight (A), epididymal fat mass (B), insulin tolerance test (C) and glucose decay rate (K_itt; %/min) (D).

<p>Male C57BL6/J mice were fed with either a standard chow diet (lean) or a high-fat diet (obese) during 10 weeks. Metformin (300mg/kg/dia) was given by gavage for the last two weeks. Each column represents the mean ± SEM (n = 6) for mice sensitized lean treated with vehicle (SL), sensitized obese treated with vehicle (SO), sensitized lean treated with metformin (SL + Met) and sensitized obese treated with metformin (SO + Met). *p<0.05 (SO vs SL); #p<0.05 (SO + Met vs SO). </p

Effect of monoclonal anti-TNF-α antibody treatment (2 mg/kg) on the number of total inflammatory cells (A) and eosinophils (B) in lung connective tissue surrounding the bronchial and bronchiolar segments at 48 h following intranasal challenge with ovalbumin in sensitized mice.

<p>Anti-TNF-α antibody was given intraperitoneally at days 14 and 15 and 1 h before the first ovalbumin challenge. Representative high-power fields of bronchiolar structures from the following groups: sensitized lean (SL), sensitized obese (SO), sensitized lean treated with anti-TNF-α (SL + anti-TNF-α) and sensitized obese treated with anti-TNF-α (SO + anti-TNF-α). Panel C shows representative images of lung histology for the four experimental groups. Each column represents mean ± SEM (n = 6) of the number of cells mm². Haematoxylin–eosin, high magnification (bar represents 20 µm). *p<0.05.</p