1 Department of Biomedical Sciences, Clinical Metabolomics Unit, University of Cagliari, Cagliari, Italy. Electronic address: federica.murgia@unica.it.
3 Department of Medical Science and Public Health, University of Cagliari, Cagliari, Italy; Multiple Sclerosis Center, Binaghi Hospital, ATS Sardegna, ASSL Cagliari, Cagliari, Italy.