Metabolite changes in early relapsing-remitting multiple sclerosis. A two year follow-up study

Area of Science:

• Neuroimaging
• Biochemistry
• Neurology

Background:

• Multiple Sclerosis (MS) is characterized by neuronal and axonal damage, indicated by reduced N-acetyl-aspartate (NAA) in brain tissues.
• Metabolite changes in MS, including myoinositol (Ins), creatine (Cr), choline (Cho), and glutamate plus glutamine (Glx), are known but their temporal dynamics are unclear.

Purpose of the Study:

• To investigate the longitudinal changes in brain metabolite concentrations in early relapsing-remitting MS (RRMS).
• To characterize metabolite profiles in normal-appearing white matter (NAWM) and cortical grey matter (CGM) in early RRMS.
• To explore the relationship between metabolite changes and clinical outcomes in RRMS.

Main Methods:

• Proton magnetic resonance spectroscopic imaging ((1)H-MRSI) was performed annually for two years on 20 RRMS patients and 10 healthy controls.
• LCModel was used to quantify concentrations of total NAA (tNAA), Cr, Cho, Ins, and Glx in NAWM and CGM.
• Statistical analyses compared metabolite levels between groups and over time.

Main Results:

• Baseline tNAA was significantly reduced in the NAWM (-7%) and CGM (-8.7%) of MS patients compared to controls.
• NAWM tNAA concentrations showed a trend towards recovery from baseline in MS patients.
• No other significant longitudinal changes in metabolite profiles were observed in MS subjects or between MS and control groups.

Conclusions:

• Early neuronal and axonal damage in MS, reflected by reduced tNAA, may be partly reversible.
• Serial (1)H-MRSI may be less sensitive to progressive pathological changes in early RRMS compared to other MRI techniques.
• Further research is needed to understand the long-term implications of these metabolite dynamics in MS progression.