A new study by scientists at Yale University have identified a flaw in our protection from colds. First and foremost, the risk group includes smokers, but a new discovery for everyone who is faced with toxic substances in the air. The results of their study published in the journal Cell Reports, show that the protective forces of the body at the same time difficult to cope with viruses and other harmful influences.
Rhinovirus is the main cause of colds and exacerbations of asthma. When this virus enters the nose, the epithelial cells of the respiratory tract react and often clean the body from him before the virus can multiply and cause symptoms. However, in other cases people who gets the virus become ill. And a group of American researchers led by Ellen Foxman (Foxman Ellen) has identified why this is happening.
The research team used the epithelial cells from the nasal passage and lungs, taken from healthy donors. The obtained cells were exposed to the rhinovirus. To their surprise, the researchers found a more powerful response to the virus in the cells of the nose.
The researchers then activated the tracking mechanism of the virus, known as RIG-I, as in the cells of the nose and lung cells. They found that both types of cells generate the antiviral response and protective response to oxidative stress (the cell damage caused by viruses and other inhaled irritants such as cigarette smoke or pollen). In the nasal cells antiviral response was stronger, and in bronchial cells, the stronger was the response to oxidative stress.
In the course of further experiments, the research team found that both the reaction mechanism are activated alternately: the reaction of protection from oxidative stress disables the antivirus protection.
Then a group of researchers subjected the cells of the nose the effects of oxidative stress in cigarette smoke, and then the effects of the common cold virus and found that the nasal cells become more susceptible to the virus.
They survive after exposure to cigarette smoke, but then can’t fight a virus that begins to multiply faster, says Foxman. However, according to Foxman, it is not only a problem of smokers and non-smokers daily exposed to other chemical substances in the inhaled air.
According to Foxman, the data indicate the existence of a delicate balance between the different protection mechanisms of the body.
The protection system protects the respiratory tract from viruses and harmful substances that get into the Airways. And it works fine, when faced with only one of these factors. But when she immediately affect two different factors, it works on the principle of either-or.
We found that when our Airways are trying to cope with one type of stress, they cope well, but at the expense of susceptibility to another type of stress in this case, rhinovirus, says Foxman.
The study, she said, shows the mechanistic link between environmental exposures and susceptibility to colds, and also may explain why smokers are more susceptible to rhinovirus infection. The researchers hope that their study will lead to new strategies against respiratory viruses.
Dmitry Kolesnik