ufotruth at ix.netcom.com wrote:
>> On 1 Sep 1998 14:38:56 GMT, tdlaing at nospam.dres.dnd.ca (T.D. Laing)
> >Yes, of course. My mistake, and thank you for correcting it. The aging
> >cells used in that study were at a very late passage for that cell line,
> >almost at the point of senescence, which I think is why I confused the
>> Now, please forgive me for my ignorance but does this mean that
> younger cells do express more "growth factor" than older cells with
> shorter telomeres?
That may be true of those cell which produce TGF, but it was not what
the paper showed. The TGF was exogenous to the cells that were studied
in the paper. What the paper showed was a different response between
young and "nearly" senescent cells to the stimulation by this exogenous
I have requoted below the part of the original which makes this clear.
> Exp Gerontol 1996 Jan;31(1-2):207-223
>> Differential effects of transforming growth factor-beta 1 on the
> expression of matrix metalloproteinases and tissue inhibitors of
> metalloproteinases in young and old human fibroblasts.
>> Edwards DR, Leco KJ, Beaudry PP, Atadja PW, Veillette C, Riabowol KT
>> Department of Pharmacology and Therapeutics, University of Calgary,
> Alberta, Canada.
>> The balance between the activities of matrix metalloproteinases (MMPs)
and the tissue inhibitors of metalloproteinases (TIMPs) is an important
control point in tissue remodeling. Previous studies have demonstrated
elevated expression of the MMPs collagenase and stromelysin-1 by aged
human diploid fibroblasts compared to early-passage cultures. We show
here that aging cells display an altered response to transforming
> factor-beta 1 (TGF beta 1) that selectively affects MMP mRNA expression.
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