Hope for common cold treatment
Hopes for a treatment for common cold have been raised after scientists discovered how it causes symptoms such as sneezing and a runny nose.
By Rebecca Smith, Medical Editor
Last Updated: 1:42PM BST 24 Oct 2008
The characteristic effects of a cold are not brought about directly by the virus but by its ability to turn the body's own defences against itself, scientists have found.
Up to half of common colds are caused by various strains of the human rhinovirus and new research has shown the bug triggers a domino effect where the body's own defences over-react causing the familiar symptoms.
The findings could result in treatments for common colds caused by rhinovirus which strike hundreds of thousands of people each year in the UK.
Current treatments only work on allievating the symptoms rather than tackling the cause of the cold.
A team at the University of Calgary, in Canada, took samples from the noses of 35 volunteers, 17 of whom had been infected with a rhinovirus.
Samples taken eight hours after the inoculation showed no changes but after two days the researchers found more than 6,500 genes had been changed in the group who had the rhinovirus compared to those who were not infected.
The response seems to be "out of proportion" to the threat posed to the cold, experts said.
The genes that had been altered by the virus included those which make anti-viral proteins which fight the infection and also those involved in inflammation and would cause the stuffy blocked nose feeling and cause a runny nose.
The production of a protein that is known to help fight off flu was also found to be much higher in those infected with rhinovirus who had levels 6.5 times higher than people not infected with the bug. This shows the body tries to fight off a cold in a similar way it would deal with flu.
Prof David Proud, Department of Physiology and Biophysics at the University of Calgary, and lead author of the study, said: "The study's findings are a major step toward more targeted cold prevention and treatment strategies while also serving as a valuable roadmap for the broader respiratory science community.
"This is the first comprehensive picture to identify several groups of genes that are likely to contribute to the pro-inflammatory and antiviral response,"
Prof Proud added that while colds are usually considered to be minor infections of the nose and throat, they can cause serious complications for patients who have long-term ill health.
"Rhinovirus is the major cause of the common cold, but it is also an important pathogen in more serious conditions, such as asthma and chronic obstructive pulmonary disease (COPD)," he said.
The study was carried out in collaboration with scientists at the University of Virginia and Procter & Gamble, which makes over-the-counter cold treeatmentes.
"Advances in our understanding of the biology of the common cold may eventually lead to improvements in treatment or methods for prevention of colds," said Dr. Ron Turner, of the University of Virginia, one of the study's authors.
Specifically the researchers found that cells that had a faulty gene that produces a protein called viperin had more rhinovirus. This suggests that viperin may disrupt the rhinovirus' ability to grow and multiply.
Scientists will now work on ways to manipulate viperin in the hope of finding new ways to treat rhinovirus.
Prof Proud said: "Overall these data provide new insights into the host response to HRV infection and identify several novel candidate genes that require further study to clarify their role in disease pathogenesis.
"This may identify proinflammatory, or host defense pathways that could be targeted for drug development, not only as treatments for colds but also for viral exacerbations of asthma and COPD.
The research is published in the American Journal of Respiratory and Critical Care Medicine. |
