Fig. 1

Primary demyelination may be caused either by genetic abnormalities affecting OLs or by inflammatory damage affecting myelin and OLs, as is the case in MS. While some nutrients may play a protective role against demyelination (green line), others may play a negative role (red arrow). Remyelination is the physiological response to demyelination. During remyelination, some molecules act positively (green arrows) on the process, such as chemokines and growth factors, while others may play a dual role (green arrows for positive, red lines for negative), such as certain signaling cascades and cytokines. Among environmental factors, nutrients may also play a dual role, and finally, aging has an unequivocally negative impact on the process. The interplay of these factors determines the fate of the remyelination process, whose failure leads to neurodegeneration