On Mon, 26 Jun 2000, Bryan Moss wrote:
>Not exactly related to your post but: how much "age-related"
>damage to the brain do you think might be caused by the
>failure of the aging body supporting the brain rather than
>the aging of the brain itself? In other words, if we can
>only replace the body, and lack a way to treat the brain,
>how far will this get us?
One of the major failures of gerontology has been in cornering where are
the causes of aging located. For example: Does aging originate in the
brain, the immune system, or all organs? Does aging originate in
post-mitotic cells or mitotic cells? Does aging originate in errors in
translation, transcription, the DNA itself, or none of these? Does aging
originate in the nucleus, the mitochondria, or other organell? Personally,
I don't think the basic causes of aging are present in all cells of all
organs of the body. The question is where?
Answering your question, if aging is located in a single organ, then the
brain is probably the main candidate (e.g. Sacher's equations show a
stronger correlation using the brain). If aging is caused by senescence in
mitotic tissues then you would expect a diminished decline of the brain if
you avoid aging in the body. Obviously, if aging has its origin in some
organ, tissue or system not part of the brain, then you would avoid aging.
However, you must have in mind that many age-related pathologies (e.g.
Alzheimer, Creutzfeld-Jakob, Parkinson, Machado-Joseph, to mention just
brain age-related pathologies) are probably independant of aging and would
appear even if you were to eradicate aging (from evolutionary theory, it is
logical that if lifespan does not exceed 120 then lethal mutations acting
at late ages can accumulate in all organs; but these are pathologies, not
basic causes of aging). I have a few paragraphs in my website addressing
your particular question
UnitÚ de Biologie et Biochimie Cellulaire
FacultÚs Universitaires Notre-Dame de la Paix
61, rue de Bruxelles
tel : 32-81-724321
fax : 32-81-724135
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