Acetaldehyde at a Low Concentration Synergistically Exacerbates Allergic Airway Inflammation as an Endocrine-Disrupting Chemical and as a Volatile Organic Compound

Abstract

Background: Acetaldehyde is an endocrine-disrupting chemical (EDC) and a volatile organic compound (VOC). It is also a carcinogen and teratogen that causes bronchoconstriction in a subset of asthmatics. However, the mechanism through which acetaldehyde acts as an EDC/VOC causing allergic airway inflammation remains unknown. Objectives: To determine the effects of a low concentration of acetaldehyde, which itself did not trigger airway inflammation, on extant allergic airway inflammation in a murine model of allergic asthma. Methods: We compared airway hyperresponsiveness (AHR), lung pathology, serum IgE and airway concentrations of cytokines among four groups of BALB/c mice [control, Dermatophagoides farinae(Df) allergen-sensitized (AS), intranasally acetaldehyde-injected (ALD) and AS-ALD mice]. Results: Physiological and histological differences were not evident between ALD and control mice. AS mice developed AHR and allergic airway inflammation characterized by goblet cell hyperplasia and eosinophilic infiltration. Both AHR and airway eosinophilia were significantly enhanced in AS-ALD compared with AS mice. Serum total and Df-specific IgE were significantly increased in both AS and AS-ALD mice compared with control and ALD mice, but comparable between AS and AS-ALD mice. Mite allergen sensitization significantly increased interleukin-5 and granulocyte macrophage colony-stimulating factor, and decreased interferon-γ levels in the airways; injecting acetaldehyde into airways with allergic inflammation significantly increased the levels of these inflammatory cytokines. Conclusions: Exposure to acetaldehyde can enhance allergic airway inflammation in asthma.