Tobacco smoke is an adjuvant for maintained airway sensitization in guinea pigs

Mouse models to unravel the role of inhaled pollutants on allergic sensitization and airway inflammation

Air pollutant exposure has been linked to a rise in wheezing illnesses. Clinical data highlight that exposure to mainstream tobacco smoke (MS) and environmental tobacco smoke (ETS) as well as exposure to diesel exhaust particles (DEP) could promote allergic sensitization or aggravate symptoms of asthma, suggesting a role for these inhaled pollutants in the pathogenesis of asthma. Mouse models are a valuable tool to study the potential effects of these pollutants in the pathogenesis of asthma, with the opportunity to investigate their impact during processes leading to sensitization, acute inflammation and chronic disease. Mice allow us to perform mechanistic studies and to evaluate the importance of specific cell types in asthma pathogenesis. In this review, the major clinical effects of tobacco smoke and diesel exhaust exposure regarding to asthma development and progression are described. Clinical data are compared with findings from murine models of asthma and inhalable pollutant exposure. Moreover, the potential mechanisms by which both pollutants could aggravate asthma are discussed.

The effects of allergens and tobacco smoke on the laryngeal mucosa of guinea pigs

OBJECTIVE

The purpose of this study was to investigate the effects of environmental tobacco smoke (ETS) and house dust mite allergen (HDMA) on the laryngeal mucosa of guinea pigs.

STUDY DESIGN

Prospective, controlled animal study.

SUBJECTS AND METHODS

Sixteen juvenile guinea pigs were randomly assigned to one of four treatment groups: (1) filtered air, (2) HDMA, (3) ETS, and (4) ETS and HDMA. The mucosal response of retrieved larynges was measured by eosinophil grade and stored mucin index.

RESULTS

HDMA exposure increased eosinophil grade in the supraglottis. The mean eosinophil grade in the supraglottis was 1.25 (+/-1.26) in the filtered air group. The grade increased to 3.60 (+/-0.89) in the HDMA group (P = 0.021) and 3.00 (+/-1.16) in the ETS/HDMA group (P = 0.078). HDMA and ETS exposure was associated with increased mucin index in the subglottis. The grade increased from 1.50 (+/-1.73) in the control group to 3.25 (+/-0.50) in the ETS, 2.80 (+/-1.64) in the HDMA, and 3.25 (+/-0.50) in the ETS/HDMA group (P < 0.05).

CONCLUSION

Exposure to HDMA was associated with eosinophilia in the supraglottis. Exposure to HDMA and ETS was associated with elevated mucin in the subglottis. These results provide further evidence that ETS and inhaled allergens may play a role in the development of chronic laryngitis.

Asthma symptoms and bronchial reactivity in school children sensitized to food allergens in infancy

Food allergy in infancy usually disappears but is followed primarily by respiratory allergy. We hypothesized that children allergic to common food allergens in infancy are at increased risk of wheezing illness and bronchial hyperresponsiveness during school age. In a case-control study 69 children 7.2 to 13.3 years of age allergic to egg (N = 60) and/or fish (N = 29) in early life (first 3 years) who attended our allergy outpatient clinic were recruited. They received follow-up for 1 year and were evaluated by parental questionnaire, skin prick testing, spirometry, and metacholine bronchial challenge. Another 154 children (70 sensitized to inhaled allergens) recruited selectively from a general population sample with no history of food allergy during their first 3 years served as control subjects. Twenty-three children (38.3%) maintained their sensitization to egg and 19 (65.5%) to fish; the prevalence of sensitization to > or = 1 inhaled allergen(s) increased from 59.4% to 71% during childhood. Current asthma symptoms were reported more frequently in the study group than in either control groups, sensitized to inhaled allergens and non-sensitized. Children of the study group showed a significantly increased frequency of positive response to metacholine bronchial challenge compared to the control group as a whole; the difference was statistically indicative when study groups separately were compared to the sensitized control subjects. Multivariate logistic regression analysis showed that bronchial hyperresponsiveness, as well as reported current asthma symptoms were associated with early wheezing and early sensitization to inhaled allergens but not with atopic dermatitis in infancy or persistence of egg or fish allergy. Children allergic to egg or fish in infancy are at increased risk for wheezing illness and hyperactive airways in school age; asthma and bronchial hyperresponsiveness development is mostly determined by wheezing and senzitization to inhaled allergens in early life regardless of atopic dermatitis in infancy or retention of food allergy.