Vitamin relative may aid stroke repair
By Nathan Seppa
Vitamin C can’t pass through the so-called blood-brain barrier to gain entry into
the brain, but its precursor, dehydroascorbic acid (DHA), can. Thanks to this
trait, DHA might help stroke patients retain the use of endangered parts of their
brains, a new study finds.
When a clot shuts off blood flow to part of the brain, patients sometimes receive
powerful clot-busting drugs to reopen the blocked vessel. In other people, blood
finds alternate routes to threatened areas. This resurgence of blood can’t save
brain cells that are dead, but it can salvage nearby tissue that faces a dwindling
blood supply.
Meanwhile, blood flow shut-off and restoration both unleash free radicals–highly reactive molecules that disrupt cells and complicate the capability of the smallest blood vessels, called capillaries, to nourish tissue and keep it alive.
Antioxidants such as DHA and vitamin C neutralize free radicals. To assess their
value in limiting stroke damage, David W. Golde of Memorial Sloan-Kettering Cancer
Center in New York, and his colleagues experimented with mice. The researchers
modeled strokes in people by shutting off blood flow to parts of the animals’
brains and then restoring it in some mice.
The mice getting DHA infusions as much as 3 hours after an induced stroke
preserved function in more of the brain than did mice getting vitamin C or an
inert substance, the scientists report in the Sept. 25 Proceedings of the National Academy of Sciences. Further testing is needed, but the work suggests that DHA might limit the brain area damaged by stroke, Golde says.
