Evidence that glatiramer acetate helps brain tissue recover lost structure

While traditional MRI technologies have been very useful in MS for finding and measuring lesions in the brain and spinal cord, some newer techniques are also proving useful for measuring other things, such as damage in normal-appearing (non-lesioned) tissue. One of these techniques is diffusion-weighted imaging (DWI), which analyzes how water molecules move about in a tissue. In an area of tissue that is intact and structured, such as a white matter region which contains long, ordered bundles of axons, water molecules will move around (diffuse) differently than they will in an area that has experienced damage, such as loss of myelin and severing of axons. A few DWI studies have been successfully performed in MS already but none have examined whether disease-modifying drugs affect diffusivity, so a team from the University of Buffalo conducted a small study involving MS subjects taking glatiramer acetate (Copaxone).

This study included 19 people with MS taking glatiramer acetate and 16 healthy controls for comparison. MRI scans and clinical assessments were performed at baseline, and again after one and two years. At baseline, the mean diffusivity scores were significantly higher in the MS group than the controls (1200 vs 1125 10^−6/mm2/s), reflecting more damage. However, by the end of the second year, the MS group's scores had decreased by an average of 10% while the control group's score had increased by 0.7%. A similar result was found for another DWI measure called entropy. There was no significant difference in atrophy (loss of brain volume) between the two groups over the two years.

Other studies have produced evidence that glatiramer acetate may be neuroprotective, so perhaps the decrease in diffusivity in the MS group reflects structural repair in the brain. With more study, DWI might be validated as a measure of neuroprotection -- and such measures will (hopefully) be needed as additional drugs with reparative effects are developed and tested for use in MS.

As the authors point out, this study didn't have a comparison group of MS subjects not taking glatiramer acetate, which would have been informative. The authors also hope that follow-up studies will incorporate other imaging techniques, such as MR spectroscopy which can measure quantities of different proteins used in different types of cells, or functional MRI which shows brain activation while performing tasks, and can indicate re-routing of pathways when normal pathways are damaged. Combining these different techniques will give a fuller picture of how therapies help to boost regeneration.