Tuesday, 30 October 2012

Research: Repair of grey matter lesions

Chang A, Staugaitis SM, Dutta R, Batt CE, Easley KE, Chomyk AM, Yong VW, Fox RJ, Kidd GJ, Trapp BD.  Cortical remyelination: A new target for repair therapies in multiple sclerosis. Ann Neurol. 2012  doi: 10.1002/ana.23693. [Epub ahead of print]

OBJECTIVE: Generation and differentiation of new oligodendrocytes in demyelinated white matter is the best described repair process in the adult human brain. However, remyelinating capacity falters with age in patients with multiple sclerosis (MS). Because demyelination of cerebral cortex is extensive in brains from MS patients, we investigated the capacity of cortical lesions to remyelinate and directly compared the extent of remyelination in lesions that involve cerebral cortex and adjacent subcortical white matter.

METHODS: Post-mortem brain tissue from 22 patients with MS (age 27-77 years) and 6 subjects without brain disease were analyzed. Regions of cerebral cortex with reduced myelin were examined for remyelination, oligodendrocyte progenitor cells, reactive astrocytes, and molecules that inhibit remyelination.

RESULTS: New oligodendrocytes that were actively forming myelin sheaths were identified in 30 of 42 remyelinated subpial cortical lesions, including lesions from 3 patients in their 70s. Oligodendrocyte progenitor cells were not decreased in demyelinated or remyelinated cortices when compared to adjacent normal-appearing cortex or controls. In demyelinated lesions involving cortex and adjacent white matter, the cortex showed greater remyelination, more actively remyelinating oligodendrocytes, and fewer reactive astrocytes. Astrocytes in the white matter, but not in cortical portions of these lesions, significantly upregulate CD44hyaluronan, and versican, molecules that form complexes that inhibit oligodendrocyte maturation and remyelination.

INTERPRETATION: Endogenous remyelination of the cerebral cortex occurs in individuals with MS regardless of disease duration or chronological age of the patient. Cortical remyelination should be considered as a primary outcome measure in future clinical trials testing remyelination therapies.


MS is a chronic inflammatory-demyelinating disease of the white matter (WM) of central nervous system. In addition studies have shown that a large number of lesions are located in the cortical and deep gray matter.  The available MRI data obtained on large cohorts of MSers, having different clinical forms of the disease, indicate that cortical lesions can be detected early in the disease course, sometimes even before the appearance of WM lesions, and correlate with the severity of physical disability and cognitive impairment. Remyelination in the white matter occurs but this is hampered by loss of immature oligodendrocyte (myelin-forming cell) surrounding the lesions and the production of an astrocytic scar. This study shows that in lesions in the grey matter there is evidence of robust remyelination and no loss of the immature oligodendrocyte cells. This indicates that there is nothing inherently wrong with the repair mechanism. This suggests that if we could change the environment in the white matter such that it is not hostile to repair, then it may be feasible to promote repair. Also DoctorKlaus pointed out to me that the repairing cells are lining the lesions and this will help repair the lesions.This is going to be a more difficult task than in the grey matter. If we are looking for drugs to promote repair, then it may be best to look at grey matter lesions for evidence of efficacy.

7 comments:

  1. Very interested in above,from a personal point of view I've always been interested in the possible link with Diabetes. Re promoting the correct environment I find the writings of T Wahls very interesting where diet is concerned. I'm trying to get my head round Sodium/ Potassium channels and the connection to Vit D and Calcium. I have a link to a paper it's an older one, but would appreciate anyone's more trained eye casting over it.http://star.tau.ac.il/~eshel/Bio_complexity/8.Human%20Brain/New%20roles%20for%20astrocytes-Redefining%20of%20functionl%20architecture-needergaard.pdf

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  2. Dietary Vitamin D and calcium are very different from sodium/potassium channels and calcium in neurvous function. Their involvement in the disease processes will be at very different levels.

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    1. Yes I see that. I was just broadly speaking of my interest, I know I was probably going off piste,I might go and ramble on the unrelated blog section re Diabetes/ diet/ Vit D etc etc.

      Would still like your thoughts re New roles for astrocytes: Redefining the functional architecture of the brain link (2003) and IF it fits in with your paper above ?.

      Also back to the paper you posted, is this supporting the inside - out theory ? re such papers as Will the real multiple sclerosis please stand up? and do you think there may be a change in which MS is looked at re auto-immunity ? btw this isn't going where you think it might,

      Thanks

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    2. Doesn't matter, I see the last link 'The Real MS' has been discussed (will go and take a look), but would still appreciate your thoughts re the older link.
      Thanks

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    3. http://star.tau.ac.il/~eshel/Bio_complexity/8.Human%20Brain/New%20roles%20for%20astrocytes-Redefining%20of%20functionl%20architecture-needergaard.pdf

      This link did not work for me. Maybe you can send title and journal and I will look.

      In terms of outside in and inside out I do not think it makes a difference one way on the other. The work is about repair, and not what causes the damage to oligodencrocyte in the first place. However if there was something inherently killing them you would think that they (precursors) would decline which they do not appear to do.
      The cortex has few infiltrates of immune cells in contrast to the white matter.

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  3. Hi 'MD'. I'm coming at this from my armchair :-) and since you referenced this paper in August it has got me looking at the role of the Astrocyte and whether or not they are failing in MS. It would appear my thoughts re Astrocyte failure is talking me towards Alzheimer's and Aids ( I think)

    I have spoken to another Dr who disagrees with a lot of what you're saying , although he does seem to agree and says there is no evidence of failure of the Astrocyte (I think).

    Re scarring, I've always thought this was a double edged sword, there to prevent further damage, but also inhibits repair, would that be close ?

    Speaking broadly again, I'm keen on Vit D and it's relationship to Calcium, also sodium and potassium and cell energy, glutamate receptors etc, maybe some external trauma re ..... I know it's a case of throwing all these up in the air and hope they come down in the right order, but it keeps me out of trouble, ( or does it ?)


    Anyway, what has got me all excited is the work of Maiken Nedergaard, M.D., D.M.Sc.. Not sure why the link doesn't work, but I'm sure if you Google Scholar this Lady it will bring up some interesting papers.

    https://www.urmc.rochester.edu/people/23788299-maiken-nedergaard/articles

    Regards as always.

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    1. P.S try
      Functions of astrocytes and their potential as therapeutic targets,Harold K. Kimelberg and Maiken Nedergaard

      Thanks.

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