By Ves Dimov, M.D.
Assistant Professor of Medicine and Pediatrics
University of Chicago
Role of macrolides in asthma: promise of efficacy, search for responsive phenotype continues
Macrolides, such as clarithromycin and azithromycin, possess antimicrobial, immunomodulatory, and potential antiviral properties. They are a potential therapeutic option for asthma, but the results from clinical trials have been contentious. The findings could be confounded by many factors, including the heterogeneity of asthma, treatment duration, and dose.
Recent evidence suggests effectiveness of macrolides in patients with uncontrolled severe neutrophilic asthma and in asthma exacerbations. At present, the use of macrolides in chronic asthma or acute exacerbations is not justified. Further work, including proteomic, genomic, and microbiome studies, will advance our knowledge of asthma phenotypes, and help to identify a macrolide-responsive subgroup.
Source: Wong EHC, Porter JD, Edwards MR, and Johnston S. The role of macrolides in asthma. The Lancet Respiratory Medicine 2014, early online publication 17 June. (doi:10.1016/S2213-2600(14)70107-9)
Childhood asthma phenotypes in the twenty-first century: technological advances may finally solve the problem of phenotypic complexity
A substantial proportion of asthma has its origins in childhood, but attempts to identify modifiable exposures that trigger asthma inception have yielded disappointing results. Asthma is not a single disease entity but instead consists of a number of phenotypes that share common features perhaps with different etiologies and pathophysiological pathways leading to disease.
Greater understanding of the genetic pathways underpinning asthma has also led to some insights into asthma endotypes that manifest as different clinical phenotypes. However, the challenge to translate these findings into interventions to change the natural history of asthma has yet to be overcome. Technological advances are driving the creation of massive data resources that can be brought to bear on this problem. Whether they will finally solve the problem of phenotypic complexity in asthma remains to be discovered. If they do, the possibility of personalized interventions for asthma may eventually be realized. Read the full text review below.
Source: Henderson AJ. Childhood asthma phenotypes in the twenty-first century. Breathe 2014; 10(2): 100-108. (doi:10.1183/20734735.014613)
Climate change and respiratory diseases: what are the dangers and what to do about them?
Climate change increases the amount of pollen and allergen produced by each plant, mold proliferation, and the concentrations of outdoor ozone and particulate matter at ground level. The main diseases of concern are asthma, rhinosinusitis, chronic obstructive pulmonary disease (COPD), and respiratory tract infections.
Chemical air pollutants and anthropogenic aerosols can alter the impact of allergenic pollen species via two mechanisms:
- Physical, chemical and biological interactions can change the amount and/or features of the allergens in the air, for example, via chemical stress of plants, protein nitration, and pollen breakup with allergen release.
- Susceptibility of humans to allergens can increase in the presence of chemicals and aerosols, e.g. diesel exhausts, ozone and nitrogen dioxide, as well as particulate matter.
What can we do to decrease the effects of environmental factors affecting respiratory diseases?
Suggested measures are as follows:
- Promote nonpolluting sources of energy.
- Reduce private traffic in towns and improve public transport.
- Decrease use of fossil fuels and control vehicle emissions.
- Plant nonallergenic trees in cities; proposed plantation of new trees should be evaluated by allergy specialists in order to avoid high allergenic species.
Strategies to reduce climatic changes and chemical and biological air pollution are political in nature, but citizens, in particular health professionals and societies, must raise their voices in the decision process to give strong support for clean air policies at both national and international levels.
Source: D’Amato G, Cecchi L, D’Amato M, and Annesi-Maesano I. Climate change and respiratory diseases. European Respiratory Review 2014; 23(132): 161-169. (doi:10.1183/09059180.00001714)