Role of myelin sheath energy metabolism in neurodegenerative diseases

More than any other organs, brain energy demand is entirely dependent on glucose catabolism through the oxidative phosphorylation (OXPHOS). Glucose is the major cerebral energy substrate in the nervous system (NS). Ketone bodies can be utilized as an additional substrate, but in any case, neurons critically depend on oxygen supply. This sounds quite surprising considering that NS contains few mitochondria, which are universally considered the exclusive site of OXPHOS. Several authors have hypothesized that glia may be involved in the energetic support of the axon, supposing an unknown trophic role played by myelin sheath. In fact, the myelin-forming cells, i.e., oligodendrocytes and Schwann cells in central and peripheral NS, respectively, appear fundamental for the maintenance of long-term axonal functional integrity