Allergic Eosinophil-rich Inflammation Develops in Lungs and Airways of B Cell–deficient Mice

Immunoglobulins (Ig), particularly IgE, are believed to be crucially involved in the pathogenesis of asthma and, equally, in allergic models of the disease. To validate this paradigm we examined homozygous mutant C57BL/6 mice, which are B cell deficient, lacking all Ig. Mice were immunized intraperitoneally with 10 μg ovalbumin (OVA) plus alum, followed by daily (day 14–20) 30 min exposures to OVA aerosol (OVA/OVA group). Three control groups were run: OVA intraperitoneally plus saline (SAL) aerosol (OVA/SAL group); saline intraperitoneally plus saline aerosol; saline intraperitoneally plus OVA aerosol (n = 6–7). Lung and large airway tissues obtained 24 h after the last OVA or SAL exposure were examined by light microscopy and transmission electron microscopy (TEM). The Ig-deficient mice receiving OVA/ OVA treatment had swollen and discolored lungs and exhibited marked eosinophilia both in large airway subepithelial tissue (49.2 ± 12.0 cells/mm basement membrane [BM] versus OVA/ SAL control 1.2 ± 0.3 cells/mm BM; P <0.001), and perivascularly and peribronchially in the lung (49.3 ± 9.0 cells/unit area versus OVA/SAL control 2.6 ± 0.6 cells/unit area; P <0.001). The eosinophilia extended to the regional lymph nodes. TEM confirmed the subepithelial and perivascular localization of eosinophils. Mucus cells in large airway epithelium increased from 1.5 ± 0.8 (OVA/SAL mice) to 39.5 ± 5.7 cells/mm BM in OVA/OVA treated mice (P <0.001). OVA/SAL mice never differed from the other control groups. Corresponding experiments in wild-type mice (n = 6–7 in each group) showed qualitatively similar but less pronounced eosinophil and mucus cell changes. Macrophages and CD4+ T cells increased in lungs of all OVA/OVA-treated mice. Mast cell number did not differ but degranulation was detected only in OVA/OVA-treated wild-type mice. Immunization to OVA followed by OVA challenges thus cause eosinophil-rich inflammation in airways and lungs of mice without involvement of B cells and Ig

Discovery of a potent and long-acting bronchorelaxing capsazepinoid, RESPIR 4-95

BACKGROUND: Current drugs including beta-agonists have limited smooth muscle relaxant effects on human small airways. Yet this is a major site of obstruction in asthma and chronic obstructive pulmonary disease (COPD). OBJECTIVE: This study explores human small airway relaxant effects of RESPIR 4-95, a novel chemical analogue (capsazepinoid) to capsazepine. Capsazepine was recently shown to relax small airways in a way which was independent of its TRPV(1) antagonism and independent of current bronchodilator drug mechanisms. METHOD: In vitro preparations of human small airways, 0.5-1.5mm in diameter and responding with reproducible contractions to leukotriene D(4) (LTD(4)) for 12h, were used. RESULTS: RESPIR 4-95 reversibly prevented LTD(4)-induced contractions as well as relaxed the established tonic contraction by LTD(4). RESPIR 4-95 exhibited marked improvements over the reference capsazepinoid, capsazepine, by being 10 times more potent, exhibiting twice as long duration of action after wash-out (9h), and inhibiting equally well LTD(4)-, histamine-, prostaglandin D(2) (PGD(2))-, and acetylcholine (ACh)-induced contractions. RESPIR 4-95 was distinguished from l-type calcium channel antagonist nifedipine by its greater efficacy and potency and by exhibiting increased relaxant effect by repeated exposures. Furthermore, RESPIR 4-95 was more efficacious and longer acting than the long-acting beta-agonist formoterol. CONCLUSION: Efficacy, potency, duration of action, and inexhaustibility of its relaxation of human small airways make RESPIR 4-95 an interesting lead compound for further developments aiming at drug treatment of small airway obstruction in asthma and COPD. Further work is warranted to unveil the molecular biology behind its relaxant actions

Natural allergen exposure does not diminish the sensitivity of cytokine production to glucocorticosteroids in blood cells of seasonal allergic asthma and rhinitis patients.

AbstractGlucocorticosteroid (GCS) inhibition of cytokine production is a major anti-inflammatory mechanism. However, increased production of pro-inflammatory cytokines during allergic airway inflammation has been proposed to reduce GCS effects. This study aimed to investigate whether allergic airway inflammation due to natural allergen exposure might decrease the sensitivity of granulocyte-macrophage colony-stimulating factor (GM-CSF) production to GCS in blood cells. Blood samples were collected from patients with seasonal allergic asthma (n=10) and rhinitis (n=8) and healthy subjects (n=9), before, during, and after the birch pollen season. Whole blood cultures were stimulated with LPS (10 ng/ml) and treated with budesonide (10−11−10−7 M) for 20 h. GM-CSF levels were analysed using immunoassay. Birch pollen exposure did not alter LPS-stimulated GM-CSF production, although disease symptoms and blood eosinophils increased in the patients. There were no significant differences in budesonide inhibition of GM-CSF production by blood cells of asthma and rhinitis patients compared with cells of healthy subjects before, during or after the birch pollen season and no change in response to allergen exposure. A concentration of 1 nM budesonide inhibited GM-CSF production by more than 50% at all time points. In conclusion, natural allergen exposure did not reduce the sensitivity of GM-CSF production to GCS inhibition in blood cells of seasonal allergic asthma and rhinitis patients