Smoking, viral infection reduce efficiency of lung medications

Exposure to cigarette smoke and flu virus may prevent lung medications from working properly, a new study has claimed. Chronic Obstructive Pulmonary Disease (COPD) is the collective name for lung diseases including emphysema, chronic bronchitis and chronic obstructive airways disease.

Smoking is currently the main cause of COPD and the chances of developing COPD increases the longer an individual has been smoking, researchers said.

Patients suffering from COPD have difficulties breathing, mainly due to the airflow becoming obstructed, persistent production of phlegm and frequent chest infections, they said.

Over time, the inflammation leads to permanent changes in the lung and walls of the airways thicken with more mucus being produced, researchers said.

This inflammation is caused by inflammatory proteins, for example tumour necrosis factor-alpha and interleukin-1 beta, which are involved in systemic inflammation or chronic activation of the immune system.

According to researchers from RMIT University in Australia, the effectiveness of the commonly used COPD symptom-reliever medication salbutamol is reduced on exposure to cigarette smoke and influenza A infection in an animal model of the respiratory disease.

“There is a clear need for new therapies that can overcome the limitations of current drugs used to treat COPD and associated flare-ups,” said Ross Vlahos from RMIT University.

“When combined with knowledge gained through clinical research, animal models utilising cigarette smoke exposure are a valuable tool in the quest to identify new therapies for this life-changing condition,” said Vlahos.

Cigarette smoke is a major contributor to COPD as it alters immunity and can increase a patient’s susceptibility to infection, which can worsen symptoms and cause flare-ups, researchers said. One of the most common reliever drugs used to treat flare-ups of the common lung disease known as COPD is salbutamol, they said.

This drug, which is also used to treat asthma, works by dilating a patients airways making it easier for them to breathe. The effectiveness of drugs such as salbutamol in cigarette smoke-induced lung diseases such as COPD is limited, researchers said.

The study assessed sections of lung exposed to cigarette smoke and a version of the influenza A virus. Overall, researchers found that the lung tissue exposed to cigarette smoke and viral infection was less responsive to salbutamol than tissue that was not. The findings were published in the journal Clinical Science.