Excessive Blue Light from Screens May Accelerate the Aging Process
Smartphones. Laptops. TV screens. The latest versions of these devices have something in common for use in the dark — blue light. With more and more devices using blue light for artificial illumination, there are concerns about its potential health hazard to humans. Evidence suggests that acute blue light exposure may lead to the death of cells in the retina essential for sight.
Recent research has shown that chronic blue light exposure across a fly’s lifespan leads to accelerated aging. This rapid aging process results in reduced lifespan and brain neurodegeneration even in flies with without retinas, suggesting that blue light can damage cells and tissues not specialized for light perception. Now, investigators from Oregon State University show that blue light interferes with vital metabolic pathways key to aging human cells and flies, explaining the accelerated aging caused by this artificial light.
“Our study suggests that avoidance of excessive blue light exposure may be a good anti-aging strategy,” said Dr. Jadwiga Giebultowicz, a professor at the Department of Integrative Biology at Oregon State University and senior author of this study.
Artificial Light Damages the Eye and Many Other Cell Types
Natural light is necessary for life, but prolonged exposure to artificial light with a high content of blue wavelengths is a matter of increasing concern for human health, especially regarding retinal pathologies. However, recent data on model organisms like roundworms and flies demonstrate that cells and tissues not specialized for light perception, such as the brain, can be damaged in flies kept in blue light for an extended time.
Along these lines, blue light from everyday devices, such as TVs, laptops, and phones, has been shown to have detrimental effects on a wide range of cells in our body. Studies have demonstrated that blue light can affect cells in the skin and fat and some in the nervous system (sensory neurons).
Blue Light Drives Aging by Altering Metabolite Levels
Published in Frontiers of Aging, lead author Jun Yang and colleagues investigated the effects of chronic blue light on metabolic pathways in the heads of flies. “To understand why high-energy blue light is responsible for accelerating aging in fruit flies, we compared the levels of metabolites in flies exposed to blue light for two weeks to those kept in complete darkness,” explained Giebultowicz.
However, Yang and colleagues used genetically manipulated flies with eyes missing light-receiving cells. This allowed the researchers to study how light directly affects the other tissues instead of how the body is processing light through the eyes to regulate other cells. They then split these flies, keeping half in blue light and the other half in darkness for 14 days.
The Oregon State University researchers found differences in the levels of several metabolites between the fly groups. The authors report significant alterations in these flies' energy production and cellular pathways. In particular, Yang and colleagues observed dramatic metabolic rearrangements in the heads of flies kept in blue light. “We are the first to show that the levels of specific metabolites — chemicals essential for cells to function correctly — are altered in fruit flies exposed to blue light,” said Giebultowicz.
Yang and colleagues also report that accelerated aging in flies kept in blue light is associated with altered levels of several brain neurotransmitters — molecules critical for the communication between brain cells. These flies also show the onset of neurodegeneration, consistent with accelerated aging. The results provide new insights into the specific processes impaired by blue light in cells and tissues not specialized in sensing light.
Do Human Cells Respond to Blue Light in the Same Way?
This study's metabolites altered by blue light are the same in flies and human cells. So, the authors think prolonged exposure to blue light may have similar, albeit more subtle, effects on the skin, subcutaneous fat, and other cells in the human. “The signaling chemicals in the cells of flies and humans are the same, so there is potential for negative effects of blue light on humans,“ explains Giebultowicz.
However, the experiments performed on these flies were pretty extreme. Yang and colleagues used a relatively strong blue light on the flies. Humans are not typically exposed to blue light without any darkness for two weeks, let alone years to decades (which is what the fly experiments translate to in human time). “Humans are exposed to less intense light, so cellular damage may be less dramatic,” said Giebultowicz.
The results from this study suggest that future research involving human cells is needed to establish the extent to which human cells may show similar changes in metabolites involved in energy production in response to excessive exposure to blue light.
Yang J, Song Y, Law AD, Rogan CJ, Shimoda K, Djukovic D, Anderson JC, Kretzschmar D, Hendrix DA and Giebultowicz JM (2022) Chronic blue light leads to accelerated aging in Drosophila by impairing energy metabolism and neurotransmitter levels. Front. Aging 3:983373. doi: 10.3389/fragi.2022.983373