The need for remyelinating drugs is essential for healing disabling diseases such as multiple sclerosis (MS). One of the reasons for the lack of this class of therapies is the impossibility to monitor remyelination in vivo, which is of utmost importance to perform effective clinical trials. Here, we show how optical coherence tomography (OCT), a cheap and non-invasive technique commonly used in ophthalmology, may be used to assess remyelination in vivo in MS patients. Our pioneer approach validates OCT as a technique to study remyelination of the optic nerve and reflects what is occurring in non-accessible central nervous system (CNS) structures, like the spinal cord. In this study we used the orally bioavailable small molecule VP3.15, confirming its therapeutical potential as a neuroprotective, anti-inflammatory, and probably remyelinating drug for MS. Altogether, our results confirm the usefulness of OCT to monitor the efficacy of remyelinating therapies in vivo and underscore the relevance of VP3.15 as a potential disease modifying drug for MS therapy.

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ApTOLL is an aptamer specifically designed to antagonize toll-like receptor 4 (TLR4), which is involved in the innate immunity that promotes inflammatory responses in several diseases, including multiple sclerosis (MS). MS is a chronic, immune, demyelinating and neurodegenerative disease of the central nervous system that represents the second most important cause of neurological disability in young adults. The drugs currently available to treat this disease are immunomodulators and, to date, there are no therapeutic remyelinating drugs available to manage MS. In this study, we show that TLR4 is located in post-mortem cortical lesions of MS patients and as a result, we evaluated the effect of its inhibition by ApTOLL in two different animal models of MS, that of experimental autoimmune encephalomyelitis (EAE) and the cuprizone model. ApTOLL administration ameliorated the clinical symptomatology of the affected mice, which was associated with better preservation and restoration of myelin and oligodendrocytes in the demyelinated lesions of these animals. This revealed not only an immunomodulatory but also a remyelinating effect of the treatment with ApTOLL which was corroborated on purified cultures of rodent and adult human oligodendrocyte precursor cells (OPCs). In summary, the molecular nature of ApTOLL and its mechanism of action strongly supports its further study and use in novel strategies to treat MS and eventually, other demyelinating diseases.