The brake on neurodegeneration

In this issue of Neurology®, Ciccarelli et al.¹ present an intriguing study assessing 14 patients with multiple sclerosis (MS) at the time of an acute relapse related to a lesion at the spinal C1–C3 level. The authors performed magnetic resonance spectroscopy (MRS) and atrophy measurements on spinal cords of these 14 patients with MS and 13 age- and gender-matched healthy controls. Spinal N-acetylaspartate (NAA) concentrations were calculated at baseline and followed for 1, 3, and 6 months, as was spinal cord cross-sectional area. The investigators found that after an initial decrease in the first month, NAA levels recovered partially in the months after the inflammatory demyelinating event, and that patients who recovered showed a greater increase in NAA after 1 month. Spinal cord cross-sectional area gradually decreased over time and was independent of NAA recovery and, interestingly, of clinical outcome. The authors report that longer disease duration at baseline predicted less NAA recovery over time, suggesting that repair processes become “burnt-out” (i.e., less effective) with progressing disease.

NAA is abundantly present in the human CNS, especially in neurons, and decreased levels of NAA, …