Researchers: Short Telomeres Increased Risk of Emphysema in Mice
smoking cigarettes is the most common risk factor for emphysema, it is not
known why some people are more prone to developing the disease than others.
from Johns Hopkins University suggest that telomeres, the body’s own cellular
clocks, may be a crucial factor underlying the development of emphysema, according to a press release issued by the American Thoracic Society.
found that in mice that have short telomeres, there was a significant increased
risk of developing emphysema after exposure to cigarette smoke,” said Mary
Armanios, MD, assistant professor of oncology at the Johns Hopkins School of
study appears online ahead of the print edition of the American Journal of
Respiratory and Critical Care Medicine.
are DNA protein structures that protect chromosome ends from degradation. Their
length is genetically determined, but they also shorten progressively with cell
division. Short telomeres are considered one marker of aging in cells.
Dr. Armanios and her colleagues examined the
role of telomeres in lung disease by studying mice that have shortened
telomeres. The mice were exposed to cigarette smoke for six hours a day, five
days a week for six months. After exposure to cigarette smoke, they
surprisingly developed emphysema. In contrast, mice with long telomeres did not
develop lung disease.
“We found that cells with damaged DNA stopped dividing, and lung
cells with too much damage could no longer be repaired, thus contributing to
the emphysema,” Dr. Armanios said. “These results are one of the clearest
examples of telomere length, which is an inherited factor, interacting with an
environmental insult to cause disease. In fact, our results in mice suggest
that short telomeres might contribute to how cigarette smoke accelerates aging in
the lung in some individuals.”
Dr. Armanios hopes that this new research will lead into new
insights into identifying new ways to preserve lung function with age.
Previously, Dr. Armanios and her group had shown that shortened
telomeres cause idiopathic pulmonary fibrosis. IPF occurs with emphysema in
some individuals, and the incidence of both disorders increases with age and
with smoking. “By linking telomere length to both disorders, there is now clear
suggestion that they may share a common mechanism that can be traced to
Further research must be
done to confirm that the observed findings are applicable to humans, and, if
so, what mechanisms might underlie them.