Proinflammatory pattern in the lower airways of non-asthmatic obese adolescents

Obesity is known to be a pro-inflammatory condition affecting multiple organs. Obesity as a systemic pro-inflammatory state, might be associated with bronchial inflammation in non-smoking adolescents with a BMI ≥ 30 kg/m² without evidence of concomitant chronic diseases.

We studied non-asthmatic obese patients (n = 20; median age 15.8 years; BMI 35.0 kg/m²) compared to age matched healthy control subjects (n = 20; median age 17.5 years; BMI 21.5 kg/m²). Induced sputum differential cell counts and sputum mRNA levels were assessed for all study subjects. Serum levels of CRP, IL-6, and IL-8 were measured. Further, IL-5, IL-6, IL-8, IL-13, IL-17, TNF-α, IFN-γ, and IP-10 protein levels were analyzed in induced sputum was.

Serum CRP levels, sputum inflammatory cell load and sputum eosinophils differed significantly between obese and non-obese subjects, for sputum neutrophils, a correlation was shown with BMI ≥ 30 kg/m². Differences were also observed for sputum mRNA expression of IL6, IL8, IL13, IL17, IL23, and IFN-γ, as well as the transcription factors T-bet, GATA3, and FoxP3.

Increased bronchial inflammation, triggered by systemic or local inflammatory effects of obesity itself, may account for the higher rates of airway disease in obese adolescents.