Obesity increases eosinophil activity in asthmatic children and adolescents

Abstract

BackgroundA clear relationship between asthma and obesity has been reported, but the mechanisms remain unclear. The aim of this study was to evaluate the influence of obesity on eosinophil activity (chemotaxis and adhesion) in asthmatic children and adolescents compared with cells from healthy volunteers.MethodsAsthmatic obese (AO), asthmatic non-obese (ANO), non-asthmatic obese (NAO) and non-asthmatic non-obese (NANO) individuals were included in the present study. The chemotaxis of eosinophils after stimulation with eotaxin (300 ng/ml), platelet-activating factor (10 μM; PAF) and RANTES (100 ng/ml) was performed using a microchemotaxis chamber. The eosinophil peroxidase activity was measured to determine the adhesion activity of eosinophils cultivated on fibronectin-coated plates. The serum leptin, adiponectin, TNF-α and IgE levels were quantified using ELISA assays.ResultsThe serum IgE levels and eosinophil counts were significantly higher in asthmatic (obese and non-obese) individuals compared with non-asthmatic individuals (obese and non-obese). Spontaneous eosinophil chemotaxis was greater in the AO group compared with either the ANO or NANO groups. The activation of eosinophils using eotaxin and PAF increased eosinophil chemotaxis in the AO group. RANTES treatment increased eosinophil chemotaxis in the NAO group compared with the NANO or ANO groups. The activation of eosinophils using eotaxin significantly increased eosinophil adhesion in the AO group compared with other groups. The serum leptin and TNF-α levels were higher in obese subjects (asthmatic and non-asthmatic), whereas the levels of adiponectin did not significantly differ among these groups.ConclusionThis study is the first to show increased eosinophilic activity (chemotaxis and adhesion) associated with high serum leptin and TNF-α levels in atopic asthmatic obese children and adolescents compared with non-obese healthy volunteers.

Evaluation of Serum Leptin and Adiponectin Levels in Obese and Lean Asthmatic Children

“…In this study, eosinophil percentages of all obese subjects, whether asthmatic or not, were also significantly higher than lean counterparts, which was consistent with the finding that obesity itself increased eosinophil activity. 43 In conclusion, findings of this study suggest that having higher levels of adiponectin may have protective diseasemodifying effect(s) in asthmatic children. Anti-inflammatory mechanisms regarding adiponectin may work better in girls compared to boys in this age group.…”

Obesity and asthma: beyond TH2 inflammation

“…On the other hand, a number of clinical studies have suggested that obesity enhances inflammatory injury in the lungs of asthmatic patients [21][22][23] and, accordingly, experimental studies have also reported an increase in local inflammation in the lung from high-fat fed obese mice challenged with ovalbumin, compared to those from non-obese mice [24][25][26]. Another study with obese asthmatic patients revealed an increase in the eosinophil number located at the airway wall, but not at the lumen, suggesting that location of eosinophils in the lungs is crucial to the pathogeneses of disease [22].…”

“…Prospective studies with school-aged populations showed that asthma prevalence and incidence increase with the presence of obesity [28]. A recent study demonstrated that atopic asthmatic in obese children and adolescents presented an increased eosinophilic activity in comparison asthma in nonobese patients [23], which indicates that along with the increased incidence of asthma in obese children, disease severity is even higher in these subjects.…”

Platelet activating factor in allergies

“…29,30 Obesity is an important factor that negatively affects the control of asthma in patients with bronchial asthma. A study by Grotta et al 31 of obese children and young adults suffering from bronchial asthma has shown that they have an increased serum concentration of PAF in addition to leptin, eotaxin, RANTES, and TNF-α. These factors are responsible for chemotaxis and activation of inflammatory cells, particularly eosinophils.…”