Association between myelin content variation and clinical-radiological activity in multiple sclerosis

Introduction: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system, characterized by focal demyelinating lesions and neurodegeneration, resulting in a variety of neurological impairments, leading the remyelination to plays a key role in patients' recovery and preventing disease progression. REMIT-MS is an ongoing observational study that aims to evaluate the relationship between clinical factors and remyelination activity in MS patients treated with disease-modifying drugs (DMDs), including natalizumab (NTZ).
Methodology: In the study, 27 patients have been included (18 in the NTZ group) and underwent two evaluations over 6 months, during which clinical and magnetic resonance imaging assessments were performed using advanced sequences, including myelin evaluation through the q-space myelin map sequence, using the calculation of normalized leptokurtic diffusion (NLD). Treatment group, clinical changes, conventional neuroimaging radiological activity and NLD variation in lesions and in normal appearing white matter (NAWM) over 6 months were tested for correlations.
Results: Regarding treatment, there was a trend for NTZ group to have lower risk of new T2 lesions (OR 0.11; p = 0.07) and negative association between new T2 or enhancing lesions and the Timed 25-foot walked test (p < 0.01 and p = 0.01, respectively). NLD lesion variation was negatively associated with occurrence of new T2 lesions (p < 0.01) and new Gd+ enhancing lesions (p = 0.05). Moreover, patients with an average NLD variation < 5 a.u over 6 months (lower quartile of the sample) had a significantly increased risk for occurrence of new T2 lesions (OR 25.7 [2.2-698.5], p < 0.01).
Conclusion: This was the first study to evaluate the association of NLD lesion variation with conventional metrics used in the radiological monitoring for MS activity. We conclude that patients with increased NLD, thus higher remyelinating activity, had a lower incidence of new T2 and Gd+ lesions.