Clinical and epidemiological studies indicate that obesity affects the development and phenotype of asthma by inducing inflammatory mechanisms in addition to eosinophilic inflammation. The aim of this study was to assess the effect of obesity on allergic airway inflammation and T helper type 2 (Th2) immune responses using an experimental model of asthma in BALB/c mice. Mice fed a high-fat diet (HFD) for 10 weeks were sensitized and challenged with ovalbumin (OVA), and analyses were performed at 24 and 48 h after the last OVA challenge. Obesity induced an increase of inducible nitric oxide synthase (iNOS)-expressing macrophages and neutrophils which peaked at 48 h after the last OVA challenge, and was associated with higher levels of interleukin (IL)-4, IL-9, IL-17A, leptin and interferon (IFN)-γ in the lungs. Higher goblet cell hyperplasia was associated with elevated mast cell influx into the lungs and trachea in the obese allergic mice. In contrast, early eosinophil influx and lower levels of IL-25, thymic stromal lymphopoietin (TSLP), CCL11 and OVA-specific immunoglobulin (IgE) were observed in the obese allergic mice in comparison to non-obese allergic mice. Moreover, obese mice showed higher numbers of mast cells regardless of OVA challenge. These results indicate that obesity affects allergic airway inflammation through mechanisms involving mast cell influx and the release of TSLP and IL-25, which favoured a delayed immune response with an exacerbated Th1, Th2 and Th17 profile. In this scenario, an intense mixed inflammatory granulocyte influx, classically activated macrophage accumulation and intense mucus production may contribute to a refractory therapeutic response and exacerbate asthma severity.

Background: Eosinophilic oesophagitis (EoE) is an emergent chronic immunemediated disease of the oesophagus, which affects both children and adults. It is clinically characterized by dysphagia, food impaction and oesophageal eosinophilia.Epidemiological studies indicate that obesity can worsen allergic symptoms; however, its effect on EoE immunopathological response has not been evaluated yet. This study aimed to assess the effect of obesity on allergic inflammation and T helper-2 profile in an EoE experimental model. Methods:Obesity was induced by high-fat feeding. After 7 weeks of diet, male BALB/c mice were subcutaneously sensitized and orally challenged with OVA.Results: Obesity itself induced a significant mast cell and eosinophil accumulation in the oesophagus, trachea, gut and lung. After allergy induction, this number was higher, when compared to lean-allergic mice. Moreover, obese-allergic mice showed higher remodelling area, in the oesophagus, associated with higher IL-5 and TSLP mRNA expression.In contrast, FoxP3 and IL-10 were less expressed in comparison with lean-allergic mice.In addition, the amount of CD11c + MHCII + PDL1 + dendritic cells was reduced, while the number of CD11c + MHCII + CD80 + DCs and CD3 + CD4 + GATA 3 + IL-4 + cells was increased in obese-allergic mice in the spleen and lymph nodes when compared to lean-allergic mice. Conclusion:Obesity aggravated the immune histopathological characteristics in the EoE experimental model, which was associated with the reduction in the regulatory profile, and the increased inflammatory cells influx, related to the T H 2 profile.Altogether, the data provide new knowledge about obesity as a risk factor, worsening EoE symptoms, and contribute for future treatment strategies for this specific profile. K E Y W O R D Sallergy, eosinophilic oesophagitis, immune response, inflammation, obesity | 245 SILVA et AL.

Summary Asthma and obesity present rising incidence, and their concomitance is a reason for concern, as obese individuals are usually resistant to conventional asthma treatments and have more exacerbation episodes. Obesity affects several features in the lungs during asthma onset, shifting the T helper type 2 (Th2)/eosinophilic response towards a Th17/neutrophilic profile. Moreover, those individuals can present reduced atopy and delayed cytokine production. However, the impact of obesity on follicular helper T (Tfh) cells and B cells that could potentially result in antibody production disturbances are still unclear. Therefore, we aimed to assess the peripheral response to ovalbumin (OVA) in a concomitant model of obesity and asthma. Pulmonary allergy was induced, in both lean and obese female BALB/c mice, through OVA sensitizations and challenges. Mediastinal lymph nodes (MLNs) and spleen were processed for immunophenotyping. Lung was used for standard allergy analysis. Obese‐allergic mice produced less anti‐OVA IgE and more IgG2a than lean‐allergic mice. Dendritic cells (CD11c+ MHCIIhigh) expressed less CD86 and more PDL1 in obese‐allergic mice compared with lean‐allergic mice, in the MLNs. Meanwhile, B cells (CD19+ CD40+) were more frequent and the amount of PDL1/PD1+ cells was diminished by obesity, with the opposite effects in the spleen. Tfh cells (CD3+ CD4+ CXCR5+ PD1+) expressing FoxP3 were more frequent in obese mice, associated with the predominance of Th (CD3+ CD4+) cells expressing interleukin‐4/GATA3 in the MLNs and interleukin‐17A/RORγT in the spleen. Those modifications to the main components of the germinal centers could be resulting in the increased IgG2a production, which – associated with the Th17/neutrophilic profile – contributes to asthma worsening and represents an important target for future treatment strategies.

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The inflammation process is a coordinated response of the organism related to immune response with release of pro-inflammatory substances, as nitric oxide, TNF-α and IL-1β. In this work, a series of lipophilic amino alcohols were evaluated on RAW264.7 and primary macrophages for the modulation of nitric oxide and TNF-α. The most potent compounds were submitted to the treatment of BALB/c mice and evaluation of the carrageenan-induced paw edema and TNF-α and IL1-β release in the paws and anti-OVA delayed type hypersensitivity reaction. RAW264.7 and primary macrophages were incubated in the presence of amino alcohols at different concentrations (1, 0.5, 0.05 and 0.005 μg mL(-1)). All tested compounds were not cytotoxic, however the inhibition of NO and TNF-α were observed only in RAW264.7 cultures. The NO production were reduced in 100% for all compounds, but only the compounds 4a and 4b expressively reduced the TNF-α release (67% and 92% respectively). On the carrageenan-induced paw edema, the compound 4b treatment showed reduction of edema, TNF-α and IL-1β as efficient as dexamethasone treatment. Meanwhile, the compound 4a treatment showed only slight reduction of paw edema. In the anti-OVA DTH reaction, both compounds showed reduction in the paw edema as effective as dexamethasone. In function of the observed results in vitro and in the acute and anti-OVA inflammation of mice paw edema compound 4b showed promissory anti-inflammatory properties.

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