Replies to post #106840 on Amarantus Bioscience Holdings Inc (AMBS)

[breezy1]

Arendt and his colleagues discovered that hyperphosphorylated tau accumulates in the brains of hibernating European ground squirrels (Spermophilus citellus). The more synapses the rodents' brains lost during hibernation, the more hyperphosphorylated tau accrued in their neurons. Within a few hours of emerging from hibernation into a period of arousal, however, the squirrels somehow scoured tau from their brains. As one way of revealing this process Arendt stained slices of brain tissue from hibernating and aroused squirrels with a dye that binds specifically to tau proteins that carry extra phosphate groups. The difference was startling. Brain tissue from hibernating squirrels was generally dark and as black as ink in some areas, whereas tissue from aroused and non-hibernating animals was completely unblemished. Arendt thinks that hyperphosphorylated tau proteins accumulate during hibernation to prevent neurons from losing even more synapses than they do and, possibly, to play a role in the swift recovery of synapses during arousal. Hyperphosphorylated tau also accumulates in the developing mammalian brain, but largely disappears soon after birth, when the brain is pruning unnecessary connections. Perhaps, Arendt proposes, tau usually protects neurons, but malfunctions in the brains of people with Alzheimer's, analogous to an overreactive immune systems in people with autoimmune disorders.
Recently, Arendt and Barnes collaborated on a study that further investigated tau proteins in hibernating ground squirrels, hamsters and black bears.
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Without intermittent arousals to clear hyperphosphorylated tau from their brains, Arendt proposes, hibernating black bears tiptoe perilously close to neurodegeneration, but somehow manage to reverse the damage when they wake up in the spring. Although these ideas about tau are controversial, Arendt and other scientists are pursuing related research because hibernating animals offer an opportunity to study Alzheimer's and related disorders in ways that would be unethical to replicate with the human brain. "
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http://www.zoominfo.com/p/Thomas-Arendt/137834653