Children exposed to cigarette smoke at home have lower levels of an enzyme that helps them respond to asthma treatment, a study has found.
Passive smoking is known to worsen asthma symptoms in children and impair their response to inhaled steroid treatment, but how this effect occurs was not known.
Researchers at Imperial College London found that children with severe asthma with a parent who smokes at home have lower levels of the enzyme HDAC2 compared with those whose parents don't smoke. HDAC2 is required for steroids to exert their beneficial anti-inflammatory effects in asthma.
The findings are reported in the journal Chest.
Professor Peter Barnes FRS, from the National Heart and Lung Institute at Imperial College London, said: "The mechanism we've identified makes children less sensitive to inhaled steroid treatment, so they suffer more symptoms and might have to take higher doses of steroids, which may lead to side effects.
"These findings underline the importance of legislation aimed at protecting children from being exposed to cigarette smoke. Restricting smoking in cars is a positive step, but the same should be applied in homes."
Over a million children in the UK have asthma. Steroid treatments, usually taken using inhalers, are given to prevent asthma attacks, but for many patients, they aren't completely effective.
The Imperial researchers studied 19 children with severe asthma receiving treatment at Royal Brompton Hospital in London. Nine had parents who smoked at home and 10 were from non-smoking households.
Cells from the lungs of children exposed to second-hand smoke had about half the levels of HDAC2 enzymes as those from children from non-smoking families.
"Children with asthma who are passively exposed to cigarette smoke have the same molecular abnormalities that lead to steroid resistance as adults who actively smoke," said Professor Barnes. "The mechanism we've identified will be a target for new treatments to help children with severe asthma."
The study was funded by the Wellcome Trust and the National Institute for Health Research (NIHR) Respiratory Biomedical Research Unit at Royal Brompton & Harefield NHS Foundation Trust and Imperial College London.
For more information please contact:
Research Media Officer
Imperial College London
Tel: +44(0)20 7594 2198
Out of hours duty press officer: +44(0)7803 886 248
Notes to editors
1. Yoshiki Kobayashi et al. 'Passive Smoking Impairs Histone Deacetylase-2 in Children With Severe Asthma.' Chest 2014; 145(2):305. Available open access at PubMed Central: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3913299/
2. About Imperial College London
Consistently rated amongst the world's best universities, Imperial College London is a science-based institution with a reputation for excellence in teaching and research that attracts 14,000 students and 6,000 staff of the highest international quality. Innovative research at the College explores the interface between science, medicine, engineering and business, delivering practical solutions that improve quality of life and the environment - underpinned by a dynamic enterprise culture.
Since its foundation in 1907, Imperial's contributions to society have included the discovery of penicillin, the development of holography and the foundations of fibre optics. This commitment to the application of research for the benefit of all continues today, with current focuses including interdisciplinary collaborations to improve global health, tackle climate change, develop sustainable sources of energy and address security challenges.
In 2007, Imperial College London and Imperial College Healthcare NHS Trust formed the UK's first Academic Health Science Centre. This unique partnership aims to improve the quality of life of patients and populations by taking new discoveries and translating them into new therapies as quickly as possible.
3. About the Wellcome Trust
The Wellcome Trust is a global charitable foundation dedicated to achieving extraordinary improvements in human and animal health. It supports the brightest minds in biomedical research and the medical humanities. The Trust's breadth of support includes public engagement, education and the application of research to improve health. It is independent of both political and commercial interests. http://www.wellcome.ac.uk
4. The National Institute for Health Research (NIHR) is funded by the Department of Health to improve the health and wealth of the nation through research. Since its establishment in April 2006, the NIHR has transformed research in the NHS. It has increased the volume of applied health research for the benefit of patients and the public, driven faster translation of basic science discoveries into tangible benefits for patients and the economy, and developed and supported the people who conduct and contribute to applied health research. The NIHR plays a key role in the Government's strategy for economic growth, attracting investment by the life-sciences industries through its world-class infrastructure for health research. Together, the NIHR people, programmes, centres of excellence and systems represent the most integrated health research system in the world. For further information, visit the NIHR website (http://www.nihr.ac.uk).
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.