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The plot thickens...



Contrasting Roles for Axonal Degeneration in an Autoimmune versus Viral Model of Multiple Sclerosis: When Can Axonal Injury Be Beneficial?

Am J Pathol. 2007 Jan;170(1):214-26.
Tsunoda I, Tanaka T, Terry EJ, Fujinami RS.
Department of Neurology, University of Utah School of Medicine, 30 North 1900 East, Room 3R330, Salt Lake City, UT 84132. robert.fujinami@hsc.utah.edu.

Although demyelination is a cardinal feature in multiple sclerosis, axonal injury also occurs. We tested whether a delay in axonal degeneration could affect the disease severity in two models for multiple sclerosis: experimental autoimmune encephalomyelitis (EAE) and Theiler's murine encephalomyelitis virus (TMEV) infection.

We compared wild-type C57BL/6 (B6) mice with C57BL/Wld(s) (Wld) mice, which carry a mutation that delays axonal degeneration. In EAE, both mouse strains were sensitized with myelin oligodendrocyte glycoprotein (MOG)(35-55) peptide and showed a similar disease onset, MOG-specific lymphoproliferative responses, and inflammation during the acute stage of EAE. However, during the chronic stage, B6 mice continued to show paralysis with a greater extent of axonal damage, demyelination, and MOG-specific lymphoproliferative responses compared with Wld mice, which showed complete recovery. In TMEV infection, only Wld mice were paralyzed and had increased inflammation, virus antigen-positive cells, and TMEV-specific lymphoproliferative responses versus infected B6 mice.

Because TMEV can use axons to disseminate in the brain, axonal degeneration in B6 mice might be a beneficial mechanism that limits the virus spread, whereas slow axonal degeneration in Wld mice could favor virus spread. Therefore, axonal degeneration plays contrasting roles (beneficial versus detrimental) depending on the initiator driving the disease.

Pubmed reference

Huh???

I thought it was interesting because axonal degeneration is now widely acknowledged to be an important aspect of MS progression, and this research suggests that in cases where a virus is involved, axonal degeneration can actually be of benefit by slowing the spread of the virus...or at least that's my layperson's take on this abstract.

So, if some / all MS cases are linked to a virus, it's possible that a bit of axonal degeneration could be beneficial. Since this was done on mice, not people, I guess no firm conclusions about MS can really be drawn from it though.

I think you understood the article correctly, however I think (ie I could be way wrong) that most people who believe in a virus association with MS see it as some form of trigger not actually causing the damage as in the above example.

Good point, I guess there aren't many who believe viruses are eating our CNS's.