One obstacle to developing an effective therapeutic strategy to treat or prevent asthma is that the fundamental causes of asthma are not totally understood. Asthma is thought to be a chronic TH2 immune-mediated inflammatory disease. Epigenetic changes are recognized to play a role in the initiation and maintenance of a TH2 response. MicroRNAs (miRNAs) are key epigenetic regulators of gene expression, and their expression is highly regulated, therefore, deregulation of miRNAs may play an important role in the pathogenesis of asthma. Profiling circulating miRNA might provide the highest specificity and sensitivity to diagnose asthma; similarly, correcting potential defects in the miRNA regulation network may lead to new therapeutic modalities to treat this disease.
BackgroundAsthma is characterized by bronchial hyperreactivity and airway remodeling. Subepithelial fibrosis, a feature of remodeling, is accompanied by activation of fibroblasts to myofibroblasts, with excessive proliferation and increased collagen, extracellular matrix protein, and profibrogenic cytokine production. Mast cells are important in the development of asthma and its fibrotic changes.ObjectiveIn this study, we aimed to investigate the direct effect of the drugs most frequently used in asthma, that is, glucocorticosteroids (dexamethasone) and shortacting β2-agonists (salbutamol), on human lung fibroblast proliferation when unstimulated or activated by mast cells or eotaxin.MethodsSubconfluent human fetal lung or bronchial fibroblasts were incubated with different concentrations of the drugs (24 h) 6 activators, and [3H]-Thymidine was added (24 h) to measure their proliferation. IL-6 production in the supernatants of confluent monolayers cultured in the presence of the drugs or forskolin (24 h) was analyzed by enzyme-linked immunosorbent assay.ResultsBoth drugs alone and in the presence of the activators enhanced fibroblast proliferation in a seemingly synergistic way for both fetal and bronchial fibroblasts. Dexamethasone was found to decrease IL-6 production, while salbutamol increased it.ConclusionsThese observations if corroborated by in vivo data may possibly account for the deleterious effect of long-term therapy with β2-bronchodilators and inhaled glucocorticosteroids on the natural history of asthma.
We investigated the effect of electroconvulsive therapy (ECT) on platelet vesicular monoamine-transmitter-transporter 2 (pVMAT2) using high-affinity [(3)H]dihydrotetrabenazine binding to platelet VMAT2 in 11 women and 7 men, aged 53.7 +/- 15.8. The Hamilton Depression Rating Scale (HAM-D) and the binding characteristic of pVMAT2 were assessed before and after six ECTs, administered over 21 days. A significant reduction (4.5 +/- 0.46; 20.8%) was obtained in HAM-D scores (p < 0.01) following the ECTs. The pVMAT2 density (B (max)) and affinity values (K (d)) remained unaltered. Six ECTs are not sufficient for modulation in pVMAT2 expression. Long-term studies are needed to clarify the relationship between full remission and possible alterations in platelet/brain VMAT2 characteristics.
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