 <p class="lead" id="first">Intense light activates proteins shown to protect against lung damage in mice, a discovery that could have major therapeutic implications for treating diseases like acute lung injury in humans, according to a new study from researchers at the University of Colorado Anschutz Medical Campus.</p><p>"Acute lung injury has a mortality rate of 40%," said the study's lead author Tobias Eckle, M.D., professor of anesthesiology at the University of Colorado School of Medicine. "No specific therapy exists, and novel treatment options are needed."</p><p>The study was published this week in the <em>American Journal of Physiology -- Lung Cellular and Molecular Physiology.</em></p><p>Eckle's team, which previously demonstrated that light can protect against cardiovascular disease, housed mice under intense rather than ambient light for seven days. This prompted a strong increase in the trough and peak levels of the pulmonary circadian rhythm protein -- Period 2 or PER2.</p><p>If the protein was deleted in a specific lung cell known as the alveolar type 2 cell, acute lung injury was fatal. If the protein was not deleted, 85% of the mice survived. Alveolar type 2 cells have long been recognized as playing an important role during acute lung injury but have never been linked to the light regulated protein PER2.</p><p>The study also showed that intense light therapy reduced lung inflammation or improved the function of the alveolar barrier -- the blood-air barrier -- in lung infections. Researchers saw the same reaction when using the flavonoid, nobiletin, found in orange peel, which also enhances the amplitude of PER2.</p><p>At the same time, the researchers found that intense light stimulated production of the BPIFB1 protein, known to be anti-bacterial and secreted within the mucus membranes of the large airways. They believe this also likely plays a role in protecting the lungs.</p><p>Discovering that intense light can protect against lung damage, Eckle said, is important due to the lack of therapies currently available to treat the condition.</p><p>"If you develop lung injury there is essentially no good therapy left," he said. "Our study has shown that intense light elicited lung-protective mechanisms could lead to new therapies even after the onsetof acute lung injury in the future."</p>