A fundamental assumption in neuroscience has long held that myelin's primary role is electrical insulation — speeding signal conduction along axons. A discovery that myelin also actively stores and releases oxygen to power axonal metabolism reframes our understanding of white matter biology and has significant implications for multiple sclerosis, aging-related cognitive decline, and any condition where myelination is compromised.
Published in PNAS, this research demonstrates that the lipid-rich myelin sheath is not metabolically inert but instead functions as a dynamic oxygen reservoir. The study shows that myelin stores molecular oxygen within its hydrophobic lipid layers and releases it to support aerobic ATP production in the underlying axon. This oxygen buffering capacity appears critical for sustaining axonal function during periods of high metabolic demand or transient vascular insufficiency — conditions that neurons in the central nervous system regularly encounter. The finding positions myelin as an active participant in axonal bioenergetics rather than a passive structural coating.
This work intersects with an emerging body of research recognizing white matter as metabolically active tissue. Previous models struggled to explain how long axonal segments — sometimes far from capillaries — maintain sufficient energy supply during intense neural activity. An oxygen-storing myelin layer provides a mechanistically elegant answer. For healthy aging adults, this finding carries particular weight: myelin integrity declines with age, and the cumulative bioenergetic deficit from diminished oxygen buffering could contribute to the white matter lesions and cognitive slowing observed in older populations. For demyelinating diseases like MS, the metabolic consequences of myelin loss may extend well beyond conduction failure. The primary limitation at this stage is whether these findings, established in experimental models, translate cleanly to intact human neural tissue. If confirmed, targeting myelin oxygen capacity could open entirely new therapeutic angles for neuroprotection.