Photobiomodulation (PBM) – Red lights on the brain

Red light’s many ways of working

Don’t discount the indirect effect of red and near infrared light.

I’ve had a number of queries lately about the importance of penetration of red and near infrared light into the brain. The questions stem from an assumption that red and near lights will only be effective if they act directly onto the cell. This assumption isn’t correct. Red light doesn’t rely on just one method to be effective.

Wavelengths matter

A recent article compared the action of visible red 660nm with near-infrared 980nm.

The 660nm wavelength is a very lovely and rich shade of red, very much like the red velvet in Gwen’s photo of theatre curtains. In contrast, the wavelength 980nm is way out of the visible range and our eyes cannot see it at all.

This study showed that both wavelengths stimulated the cells into action through the mitochondria, the powerhouses inside cells. When the 980nm wavelength was used, it quickly stimulated the cell, but the effect died away pretty quickly.

In contrast, the visible red 660nm was slower to get going, but the effect lasted for at least 24 hours.

What does this finding mean?

Remember that mitochondria are like batteries, powering the cell to keep it healthy and active. The longer the mitochondrial batteries remain powered up, the longer the cell will function and – very importantly – the longer it will live.

Visible red 660nm, a rich colour to our eyes, is also a rich source of energy for our cells, and the energy that this wavelength generates will last for well over a day.

There has been interest in the use of longer wavelengths (900-1100nm) for light hats. This research article strongly suggests that it would be better to stick to visible red wavelengths.

Reference:

Fuchs, Christiane, Merle Sophie Schenk, Linh Pham, Lian Cui, Richard Rox Anderson, and Joshua Tam. “Photobiomodulation Response From 660 Nm Is Different and More Durable Than That From 980 Nm.” Lasers in Surgery and Medicine 53, no. 9 (November 1, 2021): 1279–93.

Thanks to Gwen King on Unsplash for the lovely image.

Transcranial lights are the way to go.

Here’s a new journal article from the Journal of Alzheimer’s Disease. I’m a co-author, but don’t let that get in the way.

This article looks at the animal and clinical evidence for the use of transcranial and intracranial red and near infrared light devices. There is a lot of detailed information, including and in-depth description of the effect of transcranial red and near infrared lights in people with Parkinson’s disease.

As for which is best – intracranial or transcranial? The verdict is that neither is best on its own. The best is having both working together. It makes sense, having light shining from inside and outside the brain.

Alas, you might be waiting a while before you get access to an intracranial light implant (think DBS with a 670nm LED light), but you can use transcranial lights right now. You can make your own (instructions are here) or look at the Duo Coronet (link is here) .

Meanwhile, have a read…

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Reference

Johnstone DM, Hamilton C, Gordon LC, Moro C, Torres N, Nicklason F, Stone J, Benabid AL, Mitrofanis J. Exploring the Use of Intracranial and Extracranial (Remote) Photobiomodulation Devices in Parkinson’s Disease: A Comparison of Direct and Indirect Systemic Stimulations. J Alzheimers Dis. 2021;83(4):1399-1413. doi: 10.3233/JAD-210052. PMID: 33843683.

Wavelengths

I had an interesting query today regarding the penetration of red and near infrared light into the body.

Question:

Does the penetration of red and near infrared light increase as the wavelength increases?

Answer:

Alas, no. The human body isn’t going to make life that easy for us!

Penetration studies have shown that 810 nanometres (written as 810nm) has the best ability to penetrate through the skin and into the body tissues.

There are some wavelengths in the red and near infrared spectrum that hardly penetrate at all, while others are better. 810nm is the best.

810nm is in the near infrared range. Because it is at the very edge of our ability to see, an 810nm light looks very pale.

Visible red 670nm is pretty good, but not as good as 810nm. However, when the 670nm wavelength reaches the cell, it is highly efficient at getting the cell batteries (mitochondria) to recharge and kickstart the cell.

Thanks To Steve Harvey on Unsplash for the great photo from Nottingham.

Blood glucose and red light

There’s been increasing interest in photobiomodulation and muscles.

Researchers from Brazil have been looking further into this, curious to see what happens to blood glucose (often called blood sugar) when a combination of red and near infrared light is shone into muscles. Their interest was piqued by reports that photobiomodulation can help lower blood glucose levels in people with diabetes. Blood glucose levels stay high in diabetes and that causes all sorts of problems for the rest of the body.

Magnificent mitochondria

Thomas Ryan and David Tumbarello, two British researchers, published a very interesting two-page review article due to be published in September 2021, but made available early.

It seems that mitochondria, the batteries in our cells, aren’t merely being driven by other, more high-status, parts of the cell. It looks like the mitochondria themselves might be in the driver’s seat, at least for some aspects of their activity. We should take more notice of them.