Thursday, 3 July 2014

Nerve damage to nerve pathways above and below the site of damage

Balk LJ, Steenwijk MD, Tewarie P, Daams M, Killestein J, Wattjes MP, Vrenken H, Barkhof F, Polman CH, Uitdehaag BM, Petzold A. Bidirectional trans-synaptic axonal degeneration in the visual pathway in multiple sclerosis. J Neurol Neurosurg Psychiatry. 2014 Jun 27. pii: jnnp-2014-308189

OBJECTIVE:To investigate the coexistence of anterograde and retrograde trans-synaptic axonal degeneration, and to explore the relationship between selective visual pathway damage and global brain involvement in longstanding multiple sclerosis (MS).
METHODS: In this single-centre, cross-sectional study, patients with long standing MS (N=222) and healthy controls (HC, N=62) were included. We analysed thickness of retinal layers (optical coherence tomography), damage within optic radiations (OR) (lesion volume and fractional anisotropy and mean diffusivity by diffusion tensor imaging) and atrophy of the visual cortex and that of grey and white matter of the whole-brain (structural MRI). Linear regression analyses were used to assess associations between the different components and for comparing patients with and without optic neuritis and HC.
RESULTS: In patients with MS, an episode of optic neuritis (MSON) (inflammation of the optic nerve) was significantly associated with decreased integrity of the ORs and thinning of the peripapillary retinal nerve fibre layer (pRNFL) and macular ganglion cell complex (GCC). Lesion volume in the OR was negatively associated with pRNFL and GCC thickness in patients without optic neuritis (MSNON). The pRNFL and GCC showed associations with integrity of the OR, thickness of the primary visual cortex (only in patients with MSON), and also with global white and grey matter atrophy. In HCs, no such relationships were demonstrated.
INTERPRETATION: This study provides evidence for presence of bidirectional (both anterograde and retrograde) trans-synaptic axonal degeneration in the visual pathway of patients with MS. Additionally, thinning of the retinal pRNFL and GCC are related to global white and grey matter atrophy in addition to pathology of the visual pathway.

So if you have nerve damage in the optic nerve then you can see damage in the eye but also in the opposite direction in the brain in areas that control visual function. Suggesting that damage to the brain could have their origins in other distant sources. Therefore if you did pathology in one place the actual cause of the problem could be elsewhere....is this why pathologists have not provided a clear picture of what is occurring in MS.

3 comments:

  1. "Suggesting that damage to the brain could have their origins in other distant sources."

    Prof Mouse what do you mean by other distant sources? Outside the CNS?

    Can I ask two questions: (i) any idea when the videos from the research day will be available; (ii) what happened to the white knights posts? (it looked like something was about to happen, but it didn't).

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    1. I was meaning effects in one part of the brain affecting another.
      Not sure about videos i habe yet to see rough cut
      knights your areroght there was and it didnt

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  2. Hi guys, mouse doc and prof g , i have an big problem and big question so plz if u have an advice or anwser i will preciate this and sry for bad spelling but im from croatia .
    at 2004 i notice first symptoms like tingling at right arm and face and i had and still have visual snow , u can google it , visual snow across all my visual field i see static, so i went to neuro and i did vep test witch was abnormal neuro told me that i dont need to worry coz my mr and ct of brain where fine , so at 2009 i repeat vep witch was abnormal and at this time i found out for ms// googling and trying 4 self dx :) u know how this works :) // so i went to ms specialist at this point i did MR brain and Mr spine at yrs 09/10/11/12/13/14 all of them where normal exept 2012 witch indicates on signal at right retinal nerve witch indicates for optic neuritis, afther this my neuro send me to lumbar puncture witch was fine and test for NMO withc is fine to.Then i went to neuro opthamologist trying to get dx , i did otc test and otc where abnormal indicates on retinal thicknes after that i did octopus normal program witch where normal and octopus N1 program witch show peripheral vision loss, finally after 10 yrs of vision syptoms they gave me an dx bilateral subclinic optic neuritis , at this point they say that they cant do nothing exept monitoring coz my lubar and mr was clear ..but since i read your blog every day and i aprove your theory hit early and hard how long do i have to wait for dx .
    ps dont know if is this right thread to post this but plzz i need some advice ..and this is interesting i did 8 vep , 3 of them where abnormal 2004/2009/2011 and 5 of them where normal 2011*2/2012/2013/2014, mr all clear , lumbar clear, nmo clear , dx with hypotheriosis. ex dx rheumatic fever since i was an kid a reaction on penicilin and streptococcus, spine problems ..thnx

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