John G. Elliot,Graham M. Donovan, Kimberley C.W. Wang, Francis H.Y. Green, Alan L. James, Peter B. Noble
European Respiratory Journal 2019; DOI: 10.1183/13993003.00857-2019
Epidemiological studies report that overweight or obese asthmatic subjects have more severe disease than those of a healthy weight. We postulated accumulation of adipose tissue within the airway wall may occur in overweight patients and contribute to airway pathology. Our aim was to determine the relationship between adipose tissue within the airway wall and body mass index (BMI) in individuals with and without asthma.
Transverse airway sections were sampled in a stratified manner from post-mortem lungs of control subjects (n=15) and cases of nonfatal (NFA, n=21) and fatal (FA, n=16) asthma. The relationship between airway adipose tissue, remodelling and inflammation was also assessed. The areas of the airway wall and adipose tissue were estimated by point count and expressed as area per mm of basement membrane perimeter (Pbm). The number of eosinophils and neutrophils were expressed as area densities.
BMI ranged from 15 to 45 (kg·m−2) and was greater in NFA (p<0.05). Adipose tissue was identified in the outer wall of large airways (Pbm>6 mm), but was rarely seen in small airways (Pbm<6 mm). Adipose tissue area correlated positively with BMI and airway wall thickness in all groups. Densities of neutrophils correlated with adipose tissue area in control subjects (Pbm>6 mm, p=0.04) and both neutrophils and eosinophils in FA (Pbm>12 mm, p<0.01).
These data show that adipose tissue is present within the airway wall and is related to BMI, wall thickness and the number of inflammatory cells. The accumulation of airway adipose tissue in overweight individuals may therefore contribute to airway pathophysiology.
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Conflict of interest: Dr. Elliot has nothing to disclose.
Conflict of interest: Dr. Donovan has nothing to disclose.
Conflict of interest: Dr. Wang has nothing to disclose.
Conflict of interest: Dr. Green has nothing to disclose.
Conflict of interest: Dr. James has nothing to disclose.
Conflict of interest: Dr. Noble has nothing to disclose.