Mechanisms of Heightened Airway Sensitivity and Responses to Inhaled SO₂in Asthmatics

Abstract

Sulfur dioxide (SO2) is a problematic inhalable air pollutant in areas of widespread industrialization, not only in the United States but also in countries undergoing rapid industrialization, such as China, and it can be a potential trigger factor for asthma exacerbations. It is known that asthmatics are sensitive to the effects of SO2; however, the basis of this enhanced sensitivity remains incompletely understood. A PubMed search was performed over the course of 2014, encompassing the following terms: asthma, airway inflammation, sulfur dioxide, IL-10, mouse studies, and human studies. This search indicated that biomarkers of SO2 exposure, SO2 effects on airway epithelial cell function, and animal model data are useful in our understanding of the body’s response to SO2, as are SO2-associated amplification of allergic inflammation, and potential promotion of neurogenic inflammation due to chemical irritant properties. While definitive answers are still being sought, these areas comprise important foci of consideration regarding asthmatic responses to inhaled SO2. Furthermore, IL-10 deficiency associated with asthma may be another important factor associated with an inability to resolve inflammation and mitigate oxidative stress resulting from SO2 inhalation, supporting the idea that asthmatics are predisposed to SO2 sensitivity, leading to asthma exacerbations and airway dysfunction.

Annual SO2 exposure, asthma, atopy, and lung function in Puerto Rican children

“…In ova‐albumin sensitized mice, SO 2 exposure increased alveolar eosinophils and neutrophils, mucus hypersecretion, and Th2 cytokines (interleukin [IL]‐4, IL‐5, and IL‐13) . These and other findings suggest that SO 2 induces airway oxidative stresses and promotes a Th2 (allergic) phenotype . In a separate study of SO 2 exposure and maple tree pollen, SO 2 ‐exposed pollen (as compared to unexposed pollen) elicited increased IgE reactivity in human sera sensitized to the pollen, suggesting potentially increased allergenicity of coexposure to maple pollen and SO 2 .…”

“…Children with asthma are more susceptible to the deleterious effects of air pollution . Persons with asthma have been demonstrated to have increased susceptibility to SO 2 for reasons that are incompletely understood but may include coexisting conditions such as obesity, chronic stress, and nutrient deficiencies …”

“…Sulfur dioxide (SO 2 ) is a pollutant predominantly emitted from fossil fuel combustion. Although short‐term exposure to SO 2 leads to respiratory symptoms in children with asthma, less is known about the long‐term effects of chronic SO 2 exposure on asthma, allergic sensitization (atopy), or lung function in children …”

Establishing a method of HPLC involving precolumn derivatization by 2,2′‐dithiobis (5‐nitropyridine) to determine the sulfites in shrimps in comparison with ion chromatography

“…Despite of these remarkable advantages, sulfites should be applied with strict limitation due to their potential toxicity (da Costa Machado Matos Carvalho et al, ). People may suffer from asthmatic and allergic reactions if they ingested foods containing large amounts of sulfites, especially in free (or reversibly bound) sulfite form (Moseholm, Taudorf, & Frøsig, ; Reno, Brooks, & Ameredes, ). Besides, long‐term exposure to sulfites can cause neurotoxicity and even damage to the reproductive system (Kencebay et al, ; Marshall, Reist, Jenner, & Halliwell, ).…”

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“…The concentration of SO 2 in environment is increasing simultaneously due to enhancement in industrialization and globalization. SO 2 can easily cross the primary defence system such as epithelial cell membrane, once it cross, makes it approach to small blood capillaries, affecting peripheral blood and vitals 1 .…”