Friday, 26 February 2016

Imaging myelination

Dynamic imaging of individual remyelination profiles in multiple sclerosis.Bodini B, Veronese M, García-Lorenzo D, Battaglini M, Poirion E, Chardain A, Freeman L, Louapre C, Tchikviladze M, Papeix C, Dollé F, Zalc B, Lubetzki C, Bottlaender M, Turkheimer F, Stankoff B. Anals Neurol. 2016. doi: 10.1002/ana.24620. [Epub ahead of print]

BACKGROUND: Quantitative in vivo imaging of myelin loss and repair in patients with multiple sclerosis (MS) is essential to understand the pathogenesis of the disease and to evaluate promyelinating therapies. Selectively binding myelin in the central nervous system white matter, [11C]PIB can be used as a positron emission tomography (PET) tracer to explore myelin dynamics in MS.
METHODS: Patients with active relapsing-remitting MS (n=20) and healthy controls (n=8) were included in a longitudinal trial combining PET with [11 C]PIB and magnetic resonance imaging. Voxel-wise maps of [11 C]PIB distribution volume ratio, reflecting myelin content, were derived. Three dynamic indices were calculated for each patient: the global index of myelin content change; the index of demyelination; and the index of remyelination.
RESULTS: At baseline, there was a progressive reduction in [11 C]PIB binding from the normal-appearing white matter to MS lesions, reflecting a decline in myelin content. White matter lesions were characterized by a centripetal decrease in the tracer binding at the voxel level. During follow-up, high between-patient variability was found for all indices of myelin content change. Dynamic remyelination was inversely correlated with clinical disability (p=0.006 and beta-coefficient=-0.67 with the Expanded Disability Status Scale; p=0.003 and beta-coefficient=-0.68 with the MS Severity Scale), whereas no significant clinical correlation was found for the demyelination index.
CONCLUSIONS:[11 C]PIB PET allows quantification of myelin dynamics in MS and enables stratification of patients depending on their individual remyelination potential, which significantly correlates with clinical disability. This technique should be considered to assess novel promyelinating drugs
If you want to promote remyelination. The key is to measure it.
This has relied on electrophysiology but this means that the optic system has been the focus for studies. If you want to look in brain or spinal cord you need to be able to image it. Using a radioactive tracer this was achieved. However PIB is not specific for myelin and detects beta amyloid 

3 comments:

  1. MD then what would be the best tool to measure the amount of myelin in the brain and spinal cord?

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    1. In the living person we need an imaging tool this is one of them there are others not being my field I can't say which is best. I heard could be fingolimod PET was pretty good

      Look at 7 day image in rat slice
      http://www.ncbi.nlm.nih.gov/pubmed/17682127
      The wite matter stands out a treat.

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