[Neuroscience] Re: News on Alzheimer's Disease
j_hasenkam at yahoo.com.au
Fri Apr 7 19:29:18 EST 2006
I saw that program and found it interesting. My problem with it was the
idea that Alz has a single line of causation. Many things can lead to
Alz, from low antioxidant status, elevated cytokines, brain injury -
even in childhood (TBI is the probably the biggest risk factor, though
the APOE4 allele, typically associated with heart disease, may top
that). I've even read epidemiological studies showing, across 12
countries, a direct correlation between saturated fat intake and the
incidence of Alz.
The vascular argument undoubtedly has merit but I think it is one cause
amongst many. The question they failed to address in that program was
whether or not those big plaques were caused by the vascular leakage or
caused it. There are studies indicating that people can have
considerable plaque build up without obvious symptoms, my take on that
is that Alz becomes apparent when inflammation ensues as a result of
the plaque, possibly being initiated after tau gets in on the act.
As to the idea that one can repair the damage, I doubt that. Adult
neurogenesis is well documented but the evidence of neocortical
cellular replacement is scant, the hippocampus can obviously take up
these new cells, though approximately 50% of these cells will not make
it. Additionally, any type of inflammation, even at low levels, or
chronic glucocorticoid expression, will strongly inhibit neurogenesis.
The Alz brain is inflamed, so before one can assume repair one must
find ways to dampen the inflammation, and of course remove the plaque
The latter is possible. Microglia and perhaps astrocytes can "mop up"
amyloid. Nicotine, omega 3's, and ginkgo biloba generate transcription
of transthyretin, which facilitates this mopping up function. Once Alz
is manifesting significant symptoms though repair is unlikely. It may
be possible to prevent further damage but at this point in time and for
a long time to come the prospect of reversal remains very problematic.
Strangely however, even reducing inflammation may go a long way to
alleviating symptoms. Hell, even in normal brains low levels of
pro-inflammatory cytokines can impact on cognition. Have a look at the
research of Pollmacher, in one conference presentation he mentioned one
experiment which showed even v. low levels of cytokines, via iv LPS
infusion, where no sickness behaviour is present, will impact on
cognition. Generallyspeaking, in the elderly population, inflammation
markers such as haptoglobin and C reactive protein, are indicators of
bad things ahead.
Avoiding excess stress, maintaining good antioxidant status, regular
exercise (perhaps the most important), avoiding neuroticism, treating
depression rapidly, these and other strategies are the way to go. Once
the process starts however, it is often too late.
Anup Pillai wrote:
> The link below to the article about *Alzheimer's Disease* gives new insights
> - Thanks Peter for mentioning it.
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