Kinetic of NO₂ uptake by Phleum pratense pollen: Chemical and allergenic implications

Phleum pratense pollen was exposed to NO2 in a reactor allowing a continuous analysis of NO2 concentration by FTIR. The uptake coefficient of NO2 on pollen was calculated postulating a first order kinetic reaction and a value of (1.1 ± 0.1) × 10−7 was determined. NO2 uptake was faster when the pollen water content was increased and when the pollen was pre-treated with ozone. The effect of NO2 exposure on pollen allergic properties was investigated by quantifying Th2- and Th1-associated chemokines in a model of human dendritic cells. Cellular analysis clearly showed that cells exposed to fumigated pollen favored the production of chemokines known to promote Th2-cell responses. Altogether these data demonstrate that NO2 uptake by pollen directly correlates with increased Th2 response in human cells, and are in favor of the involvement of NO2 pollution in the increase of allergic diseases

Mu opioid receptor expression is increased in inflammatory bowel diseases: implications for homeostatic intestinal inflammation

BACKGROUND AND AIMS: Recent studies with μ opioid receptor (MOR) deficient mice support a physiological anti‐inflammatory effect of MOR at the colon interface. To better understand the potential pharmacological effect of certain opiates in inflammatory bowel diseases (IBD), we (1) evaluated the regulation in vivo and in vitro of human MOR expression by inflammation; and (2) tested the potential anti‐inflammatory function of a specific opiate (DALDA) in inflamed and resting human mucosa. PATIENTS AND METHODS: Expression of MOR mRNA and protein was evaluated in healthy and inflamed small bowel and colonic tissues, isolated peripheral blood mononuclear cells and purified monocytes, and CD4(+) and CD8(+) T cells from healthy donors and IBD patients. The effect of cytokines and nuclear factor κB (NFκB) activation on MOR expression in lymphocyte T and monocytic human cell lines was assessed. Finally, DALDA induced anti‐inflammatory effect was investigated in mucosal explants from controls and IBD patients. RESULTS: MOR was expressed in ileal and colonic enteric neurones as well as in immunocytes such as myeloid cells and CD4(+) and CD8(+) T cells. Overexpressed in active IBD mucosa, MOR was significantly enhanced by cytokines and repressed by NFκB inhibitor in myeloid and lymphocytic cell lines. Furthermore, ex vivo DALDA treatment dampened tumour necrosis factor α mRNA expression in the colon of active IBD patients. CONCLUSIONS: Given the increased expression of MOR and the ex vivo beneficial effect of DALDA in active IBD, natural and/or synthetic opioid agonists could help to prevent overt pathological intestinal inflammation