CC chemokine receptor expression in childhood asthma is influenced by natural allergen exposure

Increasing selectivity of CC chemokine receptor 8 antagonists by engineering nondesolvation related interactions with the intended and off-target binding sites

The metabolic stability and selectivity of a series of CCR8 antagonists against binding to the hERG ion channel and cytochrome Cyp2D6 are studied by principal component analysis. It is demonstrated that an efficient way of increasing metabolic stability and selectivity of this series is to decrease compound lipophilicity by engineering nondesolvation related attractive interactions with CCR8, as rationalized by three-dimensional receptor models. Although such polar interactions led to increased compound selectivity, such a strategy could also jeopardize the DMPK profile of compounds. However, once increased potency is found, the lipophilicity can be readjusted by engineering hydrophobic substituents that fit to CCR8 but do not fit to hERG. Several such lipophilic fragments are identified by two-dimensional fragment-based QSAR analysis. Electrophysiological measurements and site-directed mutagenesis studies indicated that the repulsive interactions of these fragments with hERG are caused by steric hindrances with residue F656.

Bioimpedance monitoring of airway inflammation in asthmatic allergic children

BACKGROUND

Asthma in childhood is characterized by chronic inflammation. Measurement of bioimpedance (BI) is a non-invasive way of detecting airway inflammation. The aim was to compare BI with exhaled nitric oxide (eNO) and lung function evaluations in asthmatic allergic children while not exposed to offending allergens.

METHODS

22 asthmatic children allergic to house dust mites have been enrolled while residents at high altitude in an environment free of house dust mites. They were evaluated at T0 after allergen exposure at home, at T1 and at T2 after 1 and 4 months of allergen avoidance, respectively.

RESULTS

eNO decreased from 32.21 +/- 5.70 ppb at T0 to 21.92 +/- 4.36 ppb at T1, after one month at high altitude (p = 0.038), without a further decrease at T2. Data in electrical activity showed a significant decrease in conductivity of lower airways between T0 (48.53 +/- 3.53 microA) and T1 (42.08 +/- 3.47 microA) (p = 0.023). deltaB parameter (difference between conductivity of lower respiratory tract and average yield) showed significant decrease from T0 (20.75 +/- 2.64 microA), and T1 (12.84 +/- 2.52 microA) (p < 0.01), but no further decrease at T2. No difference in lung function parameters was observed.

CONCLUSION

Allergen avoidance regimen modifies inflammatory parameters in allergic asthmatics. Evaluation of extracellular bioelectrical conductivity seems to represent a promising non-invasive method to assess airway inflammation.

Effect of ciclesonide treatment on allergen-induced changes in T cell regulation in asthma

BACKGROUND

The allergen-induced release of CCL17/thymus and activation-regulated chemokine (TARC) may be crucial in asthmatic airway inflammation by recruitment of Th2 cells. In addition, it might lead to aberrant Th2 cell activity through impairment of beta2-adrenergic receptor (beta2-AR) control. We questioned how chemokine patterns change upon allergen challenge and whether treatment with the inhaled steroid ciclesonide can reduce chemokine release and subsequently prevent allergen-induced changes in Th2 cell regulation and migration.

METHODS

Asthma patients were double-blindly treated with placebo or 80 microg ciclesonide for 7 days. We studied allergen-induced changes in sputum chemokines, migration of peripheral blood T cells and control of beta2-agonist fenoterol over T cell migration and alpha-CD3/alpha-CD28-induced cytokine production.

RESULTS

Treatment with 80 microg ciclesonide significantly diminished the late asthmatic response. The late asthmatic response was associated with increased sputum levels of CCL17 and CCL4 (but none of the other chemokines measured) and loss of beta2-AR control over T cell migration and Th2-type cytokine production. Although ciclesonide treatment did not prevent chemokine release nor altered beta2-AR function in circulating T cells, it exerted an inhibitory effect on TARC-induced T cell migration and alpha-CD3/alpha-CD28-induced cytokine production.

CONCLUSION

Our data support the hypothesis that CCL17 is involved in allergen-induced dysregulation of Th2 cell migration and cytokine production. Ciclesonide treatment inhibits T cell migration and cytokine production upon allergen inhalation, which is regulated independently from reducing CCL17 release, but may contribute to beneficial effects of ciclesonide on Th2-mediated airway inflammation.