Damaging Effects of Blue Light Exposure Worsen with Age

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Blue light is a predominant component of light emitting devices, which are increasingly present in our environment. There is already accumulating evidence that blue light exposure causes damage to retinal cells. However, much less is known about potential effects of blue light on non-retinal cells. In a new study, researchers at Oregon State University investigated the effects of blue light exposure across the lifespan of the fruit fly (Drosophila melanogaster) — an important model organism because of the cellular and developmental mechanisms it shares with other animals and humans — and found that susceptibility to blue light stress is strongly age-dependent.

In general, aging is accompanied by a decline in tolerance to environmental stresses,” said study senior author Dr. Jaga Giebultowicz and her colleagues.

“Blue light-enriched light-emitting diodes (LEDs) are a relatively new factor in our homes and workspaces.”

“Therefore, it is unknown whether chronic blue light exposure across organismal lifespan could be detrimental to cellular functions and whether susceptibility to blue light may change with age.”

In their study, the researchers examined the survival rate of flies kept in darkness and then moved at progressively older ages to an environment of constant blue light from LEDs.

The darkness-to-light transitions occurred at the ages of two, 20, 40 and 60 days, and the study involved blue light’s effect on the mitochondria of the flies’ cells.

Mitochondria act as a cell’s power plant, generating adenosine triphosphate (ATP), a source of chemical energy.

In earlier research, the authors showed that prolonged exposure to blue light affected flies’ longevity, regardless of whether it shined in their eyes.

“The novel aspect of this new study is showing that chronic exposure to blue light can impair energy-producing pathways even in cells that are not specialized in sensing light,” Dr. Giebultowicz said.

“We determined that specific reactions in mitochondria were dramatically reduced by blue light, while other reactions were decreased by age independent of blue light.”

“You can think of it as blue light exposure adding insult to injury in aging flies.”

“Natural light is crucial for a person’s circadian rhythm — the 24-hour cycle of physiological processes such as brain wave activity, hormone production and cell regeneration that are important factors in eating and sleeping patterns.”

“But there is evidence suggesting that increased exposure to artificial light is a risk factor for sleep and circadian disorders.”

And with the prevalent use of LED lighting and device displays, humans are subjected to increasing amounts of light in the blue spectrum since commonly used LEDs emit a high fraction of blue light.

“This technology, LED lighting, even in most developed countries, has not been used long enough to know its effects across the human lifespan,” Dr. Giebultowicz said.

“There are increasing concerns that extended exposure to artificial light, especially blue-enriched LED light, may be detrimental to human health.”

“While the full effects of blue light exposure across the lifespan are not yet known in humans, accelerated aging observed in short-lived model organism should alert us to the potential of cellular damage by this stressor.”

In the meantime, there are a few things people can do to help themselves that don’t involve sitting for hours in darkness.

Eyeglasses with amber lenses will filter out the blue light and protect your retinas.

And phones, laptops and other devices can be set to block blue emissions.

“Our previous work demonstrated that daily lifelong exposure to blue light, but not other visible wavelengths, has damaging effects on the brain, motor abilities and lifespan of the model organism,” Dr. Giebultowicz said.

“Now we’re reporting that the damaging effects of blue light on the flies are strongly age dependent — the same length of exposure to the same intensity of light decreases lifespan and increases neurodegeneration more significantly in old flies than in young ones.”

The study was published in the journal npj Aging.

Y. Song et al. 2022. Age-dependent effects of blue light exposure on lifespan, neurodegeneration, and mitochondria physiology in Drosophila melanogaster. npj Aging 8, 11; doi: 10.1038/s41514-022-00092-z

https://www.sci.news/medicine/blue-ligh ... 11041.html