More than an insulator: new role discovered for myelin as an oxygen reservoir in the brain
Sketches, O2 not to scale. (A) Sketch of myelinated axon. (B) Sketch of capillary and myelinated axons. (C) Model of oxygen transport from a capillary to a myelinated axon.
(25-06-2025) The role of myelin in the brain as an electrical insulator is well known, but recent research, published in PNAS USA, reveals that myelin also has a surprising secondary function: temporarily storing and releasing oxygen.
Nerve cells communicate through electrical impulses that travel along the cell’s projections and contact points (axons, synapses, and dendrites), thereby enabling information transfer in the brain. To facilitate efficient conduction, some axons are surrounded by a myelin sheath: an insulating layer composed of stacked cell membranes. This structure prevents current loss and increases the speed of signal transmission.
Oxygen from an unexpected source
What this new research uncovers is that myelin functions not only as an electrical insulator but also serves as a temporary oxygen reservoir. Specifically, it appears that myelin can supplement the oxygen supply from the blood during periods of sudden, intense neuronal activity.
During heightened brain activity, the oxygen demand of neurons rises sharply. The blood supply—normally the primary source of oxygen—responds with a delay: it takes several hundred milliseconds before additional oxygen from the bloodstream reaches the active brain regions. In that critical first 100 milliseconds, a noticeable drop in oxygen levels occurs, known as the initial dip.
Researchers from the BioMMedA group in the Department of Electronics and Information Systems have shown that myelin can partially compensate for these temporary oxygen shortages. Using detailed molecular simulations, they demonstrated that the cell membranes that largely make up myelin can act as small storage units for oxygen molecules. The researchers then used a mathematical model based on an RC ladder network (resistor-capacitor model) to calculate how the stored oxygen in the myelin sheath could mitigate the extent of the initial oxygen dip. The results suggest that myelin provides additional metabolic support to neurons.
Implications for neurological disorders
These new insights into the role of myelin may have important implications for the understanding and treatment of neurological disorders. In various neurological diseases where myelin is damaged, not only electrical conduction but also the oxygen supply to nerve cells can be impaired. The findings suggest that treatments aimed at improving oxygen delivery in the brain may contribute to better outcomes for such conditions.
Although further research is needed, this discovery opens up a new perspective on the role of myelin in brain function.
More information
Wouter Vervust, Sina Safaei, Katja Witschas, Luc Leybaert and An Ghysels, Myelin sheaths can act as compact temporary oxygen storage units as modeled by an electrical RC circuit model, PNAS Vol. 122 | No. 20, May 20, 2025.
Contact
Prof. dr. ir. An Ghysels
IBiTech - BioMMedA group
Ghent University
Corneel Heymanslaan 10
Entrance 97, 2nd floor
9000 Gent
Belgium
https://www.ugent.be/ea/ibitech/en/research/biommeda
Em. Prof. Dr. Luc Leybaert
Physiology group, Dept. Basic and Applied Medical Sciences (BAMS)
Corneel Heymanslaan 10
Entrance 36 - 3rd floor
9000 Gent
Belgium