“We already knew that intense light can protect against heart attacks, but now we have found the mechanism behind it,” said the study’s senior author Tobias Eckle, MD, PhD.
Housing mice under intense light conditions for one week was revealed to “robustly enhance cardio protection,” which resulted in reduction of cardiac tissue damage after a heart attack; humans may also benefit from similar light exposure strategy according to the researchers.
The researchers developed a strategy to protect the heart using intense light to target and manipulate function of the PER2 gene expressed in circadia patterns in the brain region that controls circadian rhythms.
Amplifying the gene through light was found to protect cardiovascular tissues against low oxygen conditions such as myocardial ischemia which is caused by decreased oxygen flow to the heart. Light was also found to increase cardiac adenosine which is a chemical that plays a role in regulating blood flow. However, blind mice did not benefit to receive any cardio protection, indicating that there is a need for visual light perception.
Next the researchers moved on to human studies to investigate whether intense light would have similar effects. Participants were exposed to 30 minutes of intense light measured in lumens at 10,000 LUX on 5 consecutive days, along with serial blood draws. Light therapy was found to increase PER2 levels, and plasma triglycerides significantly decreased; overall metabolism was improved.
“The most dramatic event in the history of earth was the arrival of sunlight,” Eckle said. “Sunlight caused the great oxygen event. With sunlight, trillions of algae could now make oxygen, transforming the entire planet.”
“Giving patients light therapy for a week before surgery could increase cardio protection. Drugs could also be developed that offer similar protections based on these findings. However, future studies in humans will be necessary to understand the impact of intense light therapy and its potential for cardio protection,” says Eckle.
On a molecular level intensive light therapy may be a promising strategy for conditions such as myocardial ischemia, and if given before high risk cardiac and non-cardiac surgery it may offer protection against injury to heart muscle which can be fatal.
