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.
The direct effect is indeed the best way to stimulate the cell’s mitochondria into action. But that is not the only way that red light works.
Indirect effect of light
The indirect effect of red and near infrared light was first describe in 2014 by Dan Johnstone, who was then in Prof John Mitrofanis’s team at University of Sydney. The experiment was really clever, and showed that shining light on a body part away from the head could still improve symptoms of Parkinson’s disease. The best effect was from direct light, but the indirect light still had a significant and very positive effect and improved Parkinson’s symptoms.
At that stage it was thought to be because of the involvement of one or more immune cell types, and they are involved, as probably are circulating stem cells.
Then came the astonishing news that mitochondria can pop in and out of cells and, through the bloodstream, visit other parts of the body. Along the way, the mitochondria can pick up a light pulse and it seems that they can then deliver it to a cell that needs an extra energy boost.
Knowing now that mitochondria are so mobile and so active in the bloodstream is still an extraordinary thing to contemplate. But how the mitochondria know where to deliver a pulse of energy? There must be a very sophisticated signalling mechanism. We still have much to understand.
Clinical experience has consistently shown that indirect method used by red and near infrared light is powerful, much more so than is currently being appreciated.
The way that red light works is complex.
More in the next blog post…
Johnstone DM, El Massri N, Moro C, et al. Indirect application of near infrared light induces neuroprotection in a mouse model of parkinsonism – an abscopal neuroprotective effect. Neuroscience. 2014;274:93-101. doi:10.1016/j.neuroscience.2014.05.023
Al Amir Dache Z, Otandault A, Tanos R, et al. Blood contains circulating cell‐free respiratory competent mitochondria. The FASEB Journal. Published online 2020. doi:10.1096/fj.201901917RR