Why and how does light therapy work in Parkinson’s disease?
This is a great article by Prof John Mitrofanis, the world leader in photobiomodulation and Parkinson’s. It has much detail explained with great clarity. Even better, it is only two pages.
It poses two critical questions:
Can red/near infrared light protect brain cells from dying?
If yes, then how does the light do that?
In Parkinson’s Disease, cells that live deep in the brain and produce dopamine are slowly killed, and do not regenerate. As more cells die, brain dopamine levels plummet, and the symptoms of Parkinson’s Disease appear. As even more of these cells die, Parkinson’s symptoms increase. By the time of first diagnosis, a good swathe of dopamine-producing cells are now dead.
Question 1: Can light protect brain cells from dying?
Yes, in two different ways.
Direct: if red/near infrared light can shine directly onto the ailing cells, then the cells will respond, start acting normally, and eventually start producing new dopamine-producing cells. However, it is hard to get red light to penetrate into the deepest parts of the brain where dopamine cells are living.
Indirect: if red/near infrared light shines somewhere on the body, then there is a system that transports the light energy to other parts of the body, most particularly the parts of the body that are not functioning well. It is not as efficient but it can be surprisingly effective in reducing symptoms.
Question 2: How does the light do it?
This is what is currently known:
light pops some energy into the brain cell which allows the cell to increase its activity and energy production
the boosted cell sets off a series of chemical cascades
releases a chemical that opens up the blood vessels and increases blood flow to the cell and its neighbours
activates genes that are responsible for maintaining the cell’s health
starts the process to generate new brain cells
different wavelengths in the red/near infrared spectrum activate different parts of the cell and set off different cascades. All of them seem to be good for the cell.
Have a read of this article. It is an excellent collation of very recent and very good quality research into the effect of red/near infrared light on the brain.
Reference:
Mitrofanis J. Why and how does light therapy offer neuroprotection in Parkinson’s disease? Neural Regen Res 2017;12:574-5.