Aspects médicaux de l'exposition aux oxydes d'azote

Les oxydes d'azote sont souvent désignés par la formule générale NOx. On considère que parmi eux, seuls le monoxyde d'azote (NO) et le dioxyde d'azote (NO2, aussi appelé peroxyde d'azote) représentent un risque potentiel pour la santé

Retentissement d'une acidification du milieu sur la glycosylation membranaire de cellules épithéliales de trachée en culture

International audienceLes pluies acides representent une des formes les plus graves de la pollution atmospherique. Elles sont generees essendellement par solubilisation dans l'eau de deux gaz polluants: le S02 qui peut se transformer en acide sulfurique et le dioxide d'azote qui peut generer de l'acide nitrique. Ces acides conferent alors aux precipitations un pH moyen de 3,6 pouvant aller jusqu'a 2 et, de ce fait, contribuent a abaisser le pH de nombreux milieux biologiques. Ceux ci comprennent des ecosystemes entiers (lacs) mais egalement certains tissus humains comme les voies respiratoires. Des etudes ont montre que I'abaissement du pH pouvait jouer un role significatif dans l'alteration de certaines fonctions essentielles pour de nombreuses cellules, en particulier, les cellules epitheliales. Certaines de ces fonctions sont associees ä l'expression membranaire de structures complexes dans lesquelles la partie glucidique est primordiale et, dans ce cas, les acides sialiques sont incrimines

Effects of low level ozone exposure on rat pulmonary inflammatory response

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Comparison of alveolar and interstitial macrophage activation following exposure of rats to ozone

Alveolar macrophages (AM) are frequently studied because they are partly and readily collected by bronchoalveolar lavage (2)(7). Inversely, the functional characteristics of interstitial macrophages (IM), including interactions with other lung cell types under pathophysiological conditions, are essentially unknown because of their poor accessibility. Interstitial macrophages are in direct contact with matrix and other cells in the pulmonary connective tissue, and release of mediators or enzymes by these macrophages may have a greater effectiveness than if released by their sister cells in the alveolar space. The aim of this experiment was to evaluate some aspects of both alveolar and interstitial macrophages collected from rats exposed to ozone

Association between occupational exposure to irritant agents and a distinct asthma endotype in adults

International audienceAim : The biological mechanisms of work-related asthma induced by irritants remain unclear. We investigated the associations between occupational exposure to irritants and respiratory endotypes previously identified among never asthmatics (NA) and current asthmatics (CA) integrating clinical characteristics and biomarkers related to oxidative stress and inflammation.Methods : We used cross-sectional data from 999 adults (mean 45 years old, 46% men) from the case-control and familial Epidemiological study on the Genetics and Environments of Asthma (EGEA) study. Five respiratory endotypes have been identified using a cluster-based approach: NA1 (n=463) asymptomatic, NA2 (n=169) with respiratory symptoms, CA1 (n=50) with active treated adult-onset asthma, poor lung function, high blood neutrophil counts and high fluorescent oxidation products level, CA2 (n=203) with mild middle-age asthma, rhinitis and low immunoglobulin E level, and CA3 (n=114) with inactive/mild untreated allergic childhood-onset asthma. Occupational exposure to irritants during the current or last held job was assessed by the updated occupational asthma-specific job-exposure matrix (levels of exposure: no/medium/high). Associations between irritants and each respiratory endotype (NA1 asymptomatic as reference) were studied using logistic regressions adjusted for age, sex and smoking status.Results : Prevalence of high occupational exposure to irritants was 7% in NA1, 6% in NA2, 16% in CA1, 7% in CA2 and 10% in CA3. High exposure to irritants was associated with CA1 (adjusted OR aOR, (95% CI) 2.7 (1.0 to 7.3)). Exposure to irritants was not significantly associated with other endotypes (aOR range: 0.8 to 1.5).Conclusion : Occupational exposure to irritants was associated with a distinct respiratory endotype suggesting oxidative stress and neutrophilic inflammation as potential associated biological mechanisms