Dust mites more harmful to asthmatics than thought

Dust mites found in beds and pillows could cause more harm to asthmatic patients than previously thought.
Dust mites found in beds and pillows could cause more harm to asthmatic patients than previously thought. PHOTO: NUH/NUS

The bugs and their droppings can prevent DNA repair, affect lung function: Study

Dust mites found in beds and pillows could cause more harm to asthmatic patients than previously thought. A new study by researchers from NUS-SMART (Singapore- MIT Alliance for Research and Technology) found that these bugs and their faecal matter can damage a person's DNA, which can worsen lung inflammation and lead to cell death if the DNA is not repaired.

Asthma - or chronic inflammation disease of the airway - affects one in five children and 5 per cent of adults here. It is characterised by symptoms such as repeated wheezing, chest tightness and breathlessness. Patients suffer these symptoms because an immune response is triggered by the body when they inhale allergens. It is estimated that up to 85 per cent of asthmatic patients are allergic to dust mites.

In the latest study, researchers found that dust mites can directly trigger the production of oxidants known as free radicals, which can damage DNA in cells lining the airways. DNA is needed for cell repair and if the body is unable to repair its own DNA, it could lead to cell death, which could compromise lung function in the long run.

"When a person's DNA is not adequately repaired, it promotes inflammation in the bronchial epithelium cells (cells lining the lungs' airways), which are the first to come into contact with the dust mites," said Ms Chan Tze Khee, a SMART PhD student at the NUS Yong Loo Lin School of Medicine, who was involved in the research.

The DNA repair capacity among individuals varies but the findings suggest that those with weaker DNA repair capacity could be more susceptible to lung cell death caused by dust mites, added Ms Chan.

The study, published earlier this month in the Journal Of Allergy And Clinical Immunology, was conducted by exposing cultured human lung cells and animal tissues to dust mites.

Dust mites are microscopic pests that measure about 300 microns - about two times the width of a human hair strand. Their faecal matter is 10 times smaller than the width of a hair strand.

Millions of dust mites can live in bedding, mattresses, carpets and curtains, but one way to minimise their presence is to wash the items frequently, researchers said. As these bugs thrive in dark and moist environments, sunning mattresses or pillows in the open could help minimise exposure to these bugs.

Lead investigator of the project Associate Professor Fred Wong from the Department of Pharmacology at NUS Medicine said that taking more antioxidants such as Vitamin C may also help to lessen the damaging effects of dust mites.

A version of this article appeared in the print edition of The Straits Times on May 16, 2016, with the headline 'Dust mites more harmful to asthmatics than thought'. Print Edition | Subscribe