From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med
Subject: Re: Aging of cells stopped?
Date: 22 Jan 1998 17:37:30 GMT

In <34C76FB2.167EB0E7@ithe.rwth-aachen.de> Andreas John
<aj@ithe.rwth-aachen.de> writes:

>Hallo!
>
>Last week I heard that researchers found a way to stop the aging of
>cells and of creatures. Can someone please explain to somebody who
>is not an expert in this field how aging works and how they have
>stopped it? Please answer to aj@ithe.rwth-aachen.de
>
>Andreas John



   Nobody found a way to stop the aging of creatures, which isn't
connected very strongly with the failure of some cells to divide with
age.  They did figure out how to make some cells keep dividing with age
in a dish.  But these are cells which generally divide fine right up to
the time aging kills you by some other means.  So what they
accomplished in terms of keeping complicated organisms from dying of
old age, is very much unclear.  An interesting experiment, but
meanwhile keep taking your vitamins, stay thin on a low fat high plant
diet, exercise, don't smoke, do drive a large car, and see your doc for
those cancer and cholesterol screens.

                                       Steve Harris, M.D.

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.med
Subject: Re: Aging of cells stopped?
Date: 23 Jan 1998 00:45:52 GMT

In <6a8bbd$oo2@crl3.crl.com> bny@crl3.crl.com (Bradley Yearwood)
writes:

>In article <6a804q$mos@dfw-ixnews5.ix.netcom.com>,
>Steven B. Harris <sbharris@ix.netcom.com> wrote:
>>
>>   Nobody found a way to stop the aging of creatures, which isn't
>>connected very strongly with the failure of some cells to divide with
>>age. They did figure out how to make some cells keep dividing with age
>>in a dish. But these are cells which generally divide fine right up to
>>the time aging kills you by some other means.
>
>My not-particularly-informed intuitive prediction is that if one were to
>inhibit this cell aging process (telomere trimming) in a whole critter,
>you'd soon end up with a generous selection of tumors.
>
>Brad Yearwood
>Cotati, CA


   Mine, too.  We'll see.

From: Ian A. York
Newsgroups: sci.life-extension,sci.med,sci.cryonics
Subject: Re: Telomerase
Date: 8 Apr 1998 15:24:46 -0400

In article <6gfsgu$4fq@sjx-ixn10.ix.netcom.com>,
Steven B. Harris  <sbharris@ix.netcom.com> wrote:

>      Not clear cut when you consider that no cell line has a clear cut cell
>division limit. That's the biggest myth in gerontology. All that happens
>is that they slow down. If you're willing to culture for longer periods
>of time, they'll divide forever (apparently). Telomere's may explain why
>many cells in such cultures quit dividing. But not all.

I'm not quite sure what you're saying, Steven, presumably because this is
being cross-posted to sci.med for the first time; I do agree with your
fundamental point, though.  The telomere field is one that's exploded in
the past while, and the hype on it has led to widespread
misunderstandings.

Normal cells, in culture, almost always stop cell division after a certain
number of mean population doublings.  This is not a hard-and-fast, every
cell in the population stops all at once, thing; and this is probably
*not* directly due to telomere shortening.  This phase is called
"senescence".

IF you push cells past this point (which is most easily done by infecting
them with certain viruses or by transferring some oncogenes), the cells
will continue to divide AND THEY ARE QUITE HAPPY, for a while.  I
re-emphasize, the cells are competent to divide, and do not run into
problems with short telomeres.

BUT if you wait for a relatively short while, the cells WILL run into
major trouble; most of them die, there are massive chromosomal
abnormalities, and so on.  This period is called "crisis" and probably
*is* caused directly by short telomeres; the telomeres have reached a
point where they no longer protect the ends of chromosomes and there is
abnormal replication.

Senescence is an interesting and still poorly understood phase.  For
several reasons, not least because of the elegance of the explanation,
this is probably an indirect effect of telomere shortening.  That is, the
telomeres have not yet reached a critically-short length, but a read-out
of their length triggers a warning that this length is on the horizon.
What these putative signalling components are, is not known.

I don't think I really agree with your paragraph above; most of the cells
I know of (fibroblasts and lymphocytes) will actually stop growing unless
they're given at least a small push past senescence.  However, note that
telomere shortening is a stochastic process, and that there are 92
telomeres per normal cell (each chromosome has two ends); presumably, only
one chromosome-end per cell has to reach a significant point to trigger
the signal; so this means that (1) it will happen unevenly in the cell
population (the culture will not stop growing; individual cells in the
culture will) and (2) if you look at telomere length at this point the
average will be considerably longer than the trigger length, which leads
to obvious difficulties in interpretation.

>NOT a property of cancer cells.  Cancer cells (in solid tumors) don't have
>contact inhibition.  In the body they invade and metastasize.   Telomerase
>explains none of this.  Or organismal aging, either.  Sorry.

Absolutely true.  There is a gradient from normal to completely cancerous
cell, there is not a single sharp division.  There are degrees of
transformation.  It's not an all-or-nothing switch.  In many, but not all,
cancer cells, telomerase probably switches on somewhere in this gradient,
but it probably switches on pretty late in the process.  It is certainly
not the sine qua non for cancer.

Another way to think about this is to do some calculations.  The mean
population doubling time for cells to hit senescence in culture is
something like 70.  If this is a telomere-related effect, and if telomeres
are the sole checkpoint, then a single cell would generate 2^69 (two to
the power of 69) progeny cells *before* it needs telomerase.  That means
that the progeny of that single cell would weight roughly as much as the
Queen Mary.

Now, most of us aren't walking around with battleship-size tumours hanging
off us.  But if telomerase was the sole, or major, cancer checkpoint, then
that's what you'd expect.  Obviously, telomerase is not the major cancer
checkpoint, at least in the early stages.  In *late* stages (which may
well be before any cancer is clinically detectable) the cell has gone
through many changes already, has already become grossly abnormal, and now
it needs to turn on telomerase (or otherwise deal with short telomeres;
there are many other strategies besides telomerase) to continue to divide.

Ian
--
    Ian York   (iayork@panix.com)  <http://www.panix.com/~iayork/>
    "-but as he was a York, I am rather inclined to suppose him a
     very respectable Man." -Jane Austen, The History of England

From: Ian A. York
Newsgroups: sci.life-extension,sci.med,sci.cryonics
Subject: Re: Telomerase
Date: 9 Apr 1998 11:00:50 -0400

In article <352CD50B.4C4F@nospam.com>, James  <james@nospam.com> wrote:

>I don't know of anyone working on a telomerase knock-in organism, but I
>bet someone is.  So maybe we'll have more concrete answers in a year or
>two once the mice/hamsters/whatever grow old.

Not likely to be helpful.  Lab mice have very long telomeres to start
with--much longer than humans.  In the knockout mice that lack telomerase,
there were no problems for several generations.  However, with each
generation the telomeres became shorter and shorter; after enough
generations the mice run into problems with spermatogenesis, and I think
with hematopoiesis as well.  This is, of course, further evidence that
telomeres per se are not the sole factor in organismal aging.

Since telomerase deficiency didn't cause any problems in the first few
generations, adding it in isn't likely to cause huge differences.

(There are some mouse species--M. spretus, I think--that have short
telomeres, but I don't think you can readily do the genetics on them.)

Ian
--
    Ian York   (iayork@panix.com)  <http://www.panix.com/~iayork/>
    "-but as he was a York, I am rather inclined to suppose him a
     very respectable Man." -Jane Austen, The History of England

From: Steven B. Harris <sbharris@ix.netcom.com>
Newsgroups: sci.med
Subject: Re: Aging (was "telomerase")
Date: Mon, 13 Apr 1998 01:46:04 GMT

In article <6gntt1$p9t@panix3.panix.com>,
	iayork@panix.com (Ian A. York) wrote:

>In article <352EACC4.6A2A@nospam.com>, James  <james@nospam.com> wrote:
>
>>aging, all this research was done over a decade (or two) ago.  Try the
>>names Kirkwood and Cremer (1982), Botkin and Miller (1974), Cutler
>>(don't know date), and a book called "Evolution of Longevity in Animals"
>>by Woodhead and Thompson (1986).
>
>Much more than a decade ago.  The evolutionary explanation of aging was
>put forth by Sir Peter Medewar in 1952.
>
>Followups set.
>
>Ian



Yeah, but he hardly has the definitive word.  His idea is that aging is
caused by pleiotropic genes which have negative effects in old age.  That
idea sort of presumes that the machine would run forever if there weren't
these genes actively causing problems later in life.  Kirkwood et all
merely point out how silly this is-- that there are some things which
simply wear out (like your teeth) which don't have any repair systems.
And that probably includes a lot of complex structures like syncycial
myocytes, neurons, alveoli, glomeruli, etc.  You don't need antagonistic
pleiotropy to explain why these things don't undergo repair-- all you
need to do is point out that repair costs energy, and in addition would
involve programs and systems that often nature hasn't invented (because
there has been no need to).  And that's it.  Medawar had part of the
answer, but by no means all or even most of it.  His theory is akin to
saying that the reason your car doesn't last forever is because of
planned obsolescence-- built in design features which actually cause
damage in an otherwise intrinsically ageless piece of machinery.  Not
likely, says Kirkwood.  Sometimes it happens that way (semmelparous
species), but usually not.

BTW-- I'll have more to say about what REALLY happens after the so-called
"crisis" in cell cultures, after I get back home to my own computer.
Right now I'm working on laptop which is programmed with stuff that
definitately exhibits negative pleiotropy.

                                           Steve Harris, M.D.

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.life-extension,sci.med,misc.health.alternative
Subject: Re: Can a cell grow new mitochondria after they have been damaged by 
	free radicals?
Date: 4 Aug 1998 07:05:58 GMT

In <35c67bba.408744031@nntp.ix.netcom.com> ufotruth@ix.netcom.com
("William") writes:

Harris:
>Well, obviously it doesn't, since there are plenty of
complicated organisms which reproduce or simply propagate quite
well without resort to sex.  Not only corals and plants, but
insects, and even some parthenogenic lizards.  We have those
counterexamples, even if sexual reproduction were somehow to
magically repair mitochondria (which, BTW, I know of no evidence
for).<

William:
>I do not think I worded my previous question/comment clearly.
>You see according to the Mitochondrial Theory of aging free
>radicals cause an accumilation of Mitochondrial damage which is
>passed down from parent cells to daughter cells.

>Well, to test this theory it seems like they could take some
>human cells, lets just say human skin cells for example,
>immortalize them with the telomerase gene, and let them divide a
>few hundred times. While they are letting them divide every
>couple dozen of divisions they could test them for accumilated
>mitochondrial damage.


    Comment:  Look, you don't anything fancy like telomerase to
do this experiment.  Anything that immortalizes cells will do.  A
cancer virus like SV-40 will do it with just a gene or two.  Even
just letting rodent cells divide spontaneously will immortalize
them.

    And yes, they've been tested for accumulated mitochondrial
damage.  They have some, but not enough to take out mitochondrial
function.  HeLa cells, taken from a 30 year old woman named Henrietta
Lacks, in early 1951, are still dividing rapidly without sign of pause,
47 years later.  Such cells undergo a doubling in less than a day
if properly cared for.  For some continuous cultures (and they've
been in continuous cultivation somewhere over this entire time,
surely) that's around 20,000 doublings.  Maybe 100 times the
Hayflick limit which some people naively think limits human life
time due to free radical damage.  And they can still use oxygen,
so they still have working mitochondria.  In fact, they can even be
adapted to grow in abnormally high oxygen concentrations like 80%,
and when they are, their mitochondria change to use oxygen in THAT
environment.  That was done three decades after Henrietta Lacks had
died of her cancer (late in 1951).

   The bottom line is that such experiments have already been
done, and they say what you suggest: that the "free radical
mitochondrial damage theory of aging" does not describe the
rapidly dividing cells, which don't age if they have their growth
limits removed.  True, such a free radical process may cause some
"aging" or accumulated damage in non-dividing tissues like adult
insects, and mammalian muscle and CNS--- so your vitamin E may
still help fruit flies and your muscles, without making you age
as an organism any slower.  But elsewhere, rapid cell division
can make up for any reasonable amount of free radical damage,
apparently indefinitely.  Which is just what you'd guess, since
life on Earth has been going on in oxygen for more than a billion
years, and shows no signs of dying out due to the Hayflick limit
yet.

   Cells that "age" in vitro due to the Hayflick limit have been
looked at, also.  Free radicals apparently aren't involved.  For
example, you can take non cancerous mammalian cells (example:
adrenocortical cells) and grow them in oxygen free environments,
or without antioxidants (no vitamin E or selenium), and they
still grow just as fast, and double just as many times.   That
looks very bad for the free radical theory of aging in many
non-cancerous tissues, too.

                                 Steve Harris


Lab Invest 1985 Apr;52(4):420-428
Some characteristics of hyperoxia-adapted HeLa cells. A tissue culture
model for cellular oxygen tolerance.

Joenje H, Gille JJ, Oostra AB, Van der Valk P

By culturing HeLa cells at stepwise increased oxygen tensions over a
prolonged period of time (approximately 21 months) we selected a
substrain capable of growing under 80% O2/19% N2/1% CO2, an oxygen
level that is lethal to normal HeLa cells, adapted to 20% O2/79% N2/1%
CO2. The 80% O2-adapted cells exhibited the following characteristics.
At the ultrastructural level an abnormal mitochondrial morphology was
observed: compared to normal cells, mitochondria of the
hyperoxia-adapted cells exhibited a 3-fold larger mean profile area in
sections and were slightly decreased in number; the relative
mitochondrial volume was increased 2-fold, whereas the size of both
cell types was the same. Mitochondrial matrix appeared less dense in
the hyperoxia-adapted cells; no structural damage was detected.
Compared to the 20% O2-adapted cells O2 consumption per cell was
approximately 40% decreased in the 80% O2-adapted cells. Under
hyperoxic conditions 20% O2-adapted and 80% O2-adapted cells
exhibited very similar cyanide-resistant respiration rates (0.16 +/-
0.04 and 0.15 +/- 0.02 fmoles/cell/minute, respectively), suggesting
that the increased O2 tolerance of the 80% O2-adapted cells was not due
to a decreased cellular production of activated oxygen species at
hyperoxia. Cellular levels of the enzymes directly involved in
protection against activated oxygen species, i.e., superoxide
dismutases, catalase, and glutathione peroxidase, were normal or
slightly below normal in the 80% O2-adapted cells, implying that these
enzymes were of no significance for the increased O2 tolerance. In
addition, the specific activity of glucose-6-phosphate dehydrogenase, a
key enzyme for cellular production of NADPH, was not related to the
degree of O2 tolerance. Our results suggest that the increased O2
tolerance of the 80% O2-adapted cells is neither based on cellular
properties controlling the formation or removal of intracellular
activated oxygen species nor on the cellular capacity to repair
or replace damaged cellular components. We speculate that the increased
O2 tolerance is largely due to a genetically determined increased
resistance of oxygen-sensitive cellular targets.

PMID: 2984461, UI: 85161893

From: Ian A. York
Newsgroups: sci.med
Subject: Re: Can a cell grow new mitochondria after they have been damaged by 
	free radicals?
Date: 5 Aug 1998 10:15:25 -0400

In article <1998080500275500.UAA28133@ladder01.news.aol.com>,
DORFDJA <dorfdja@aol.com> wrote:
>
>Do bacteria experience an end-replication crisis of any kind?

Many viruses have an end-replication problem (all double stranded, linear
DNA viruses, such as the adenoviruses, the pox viruses and the
herpesviruses).  Interestingly, they have solved the end-replication
problem without telomerase, and by different mechanisms.

Adenoviruses get round the problem by doing this fancy bit of priming with
a protein.  Pox viruses have a whacky loop-back system for self-priming.
Herpesviruses circularize, so during replication they don't have ends.
(Although, for some really weird reason, there's at least one herpesvirus
which has telomeric sequences, apparently stolen from the host.  Why?
Lord knows.)

Not only that, there are much more complicated organisms that don't bother
with telomeres.  Drosophila (fruit flies) don't have telomeres; they use a
Rube Goldbergesque system of transposition to look after their chromosome
ends.

And let's also keep firmly in mind that not even human cells require
telomerase for immortality.  Many cancer cells do not have activated
telomerase: they use different mechanisms for maintaining chromosome ends.
And if you inactivate telomerase in yeast, the little buggers hang on
pretty well; you have to knock out other DNA repair systems before they
really run into trouble with a concommitant telomerase knockout.

Telomerase is undoubtedly a fascinating and important enzyme, but the
fuss over it has led to a lot of basic cell biology being overlooked.
There are plenty of non-telomerase options out there.

Ian
--
    Ian York   (iayork@panix.com)  <http://www.panix.com/~iayork/>
    "-but as he was a York, I am rather inclined to suppose him a
     very respectable Man." -Jane Austen, The History of England

From: Ian A. York
Newsgroups: sci.med
Subject: Re: Can a cell grow new mitochondria after they have been damaged by 
	free radicals?
Date: 6 Aug 1998 10:32:48 -0400

In article <1998Aug5.150140.15103@jarvis.cs.toronto.edu>,
Beverly Erlebacher <bae@cs.toronto.edu> wrote:
>
>a lot longer than they 'need' to be.  Cat telomeres are 15 times longer than
>human ones, even though cats are much smaller and have a much smaller life

Lab mouse telomeres are much longer than humans' too, so it's not clear
whether telomere data from mice is strictly or even loosely applicable to
humans.  (Mus spretus, which is not the common lab mouse, does have
telomeres that are more like humans' in length, so there might be more
interesting data coming from them.)

>Btw, don't just read the Geron paper.  Read Vaziri's paper.  Much nicer
>method.

I think that's one of the ones I'm acknowledged in, but I can't remember
for sure.

Ian

--
    Ian York   (iayork@panix.com)  <http://www.panix.com/~iayork/>
    "-but as he was a York, I am rather inclined to suppose him a
     very respectable Man." -Jane Austen, The History of England

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: misc.health.alternative
Subject: Re: Cause of aging
Date: 14 Aug 1998 21:41:15 GMT

In <35D45F39.E9F946E@castles.com> gtwolke <gtwolke@castles.com> writes:

>
>Doug Skrecky (hope I spelled that right,) who I believe posts to this
>newsgroup occasionally, wrote a fascinating article positing that the
>cause of aging is now known. Since much degenerative disease is linked
>to the aging process this could be good news, indeed. You can read it at
>http://www.longevb.demon.co.uk/lr33.htm
>
>Presuming that he is correct and that aging is a function of free
>radical damage in the mitochondria caused by hydrogen peroxide and the
>hydroxyl radical, rather than the superoxide radical, what are the best
>antioxidants for this species? I have come up with melatonin and
>curcurmin. Also, Microhydrin may also be a good choice.
>Are there any others?



   There isn't any reason to think that "aging" is caused by entirely
or mostly by free radicals from the mitochondria.  Many organisms have
mitochrondria, but don't age-- therefore the free radical made by
mitochondria are obviously fully containable by a healthy organism.  If
they do damage in aging, that may be because aging screws up the repair
systems.  But that doens't mean the mitochondria are the cause of
aging-- in that cause they would simply be one more system that causes
problems as aging takes out the control and repair systems.  Attempts
to influence rate of aging in cells by fooling with mitochondria
haven't been sucessful.  The Hayflick limit, for example, is not
influencable by damping out oxidative metabolism in mitochondria.

   As organisms that do age get older, their mitochondria take a
beating.  But so does the rest of them.  That's not good evidence.

                                          Steve Harris, M.D.

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: misc.health.alternative,bionet.molbio.ageing,sci.med,
	sci.life-extension
Subject: Re: Cause of aging
Date: 16 Aug 1998 19:58:06 GMT

In <6r6n7u$r6t$1@pegasus.csx.cam.ac.uk> ag24@mole.bio.cam.ac.uk (Aubrey
de Grey) writes:


Harris:
>> There isn't any reason to think that "aging" is caused by entirely
>> or mostly by free radicals from the mitochondria.  Many organisms have
>> mitochondria, but don't age-- therefore the free radical made by
>> mitochondria are obviously fully containable by a healthy organism
>
>Convincing though this may sound on the surface, it is completely
>wrong. The cells in the human body which appear to suffer
>mitochondrial damage are the non-dividing (or rarely-dividing) ones;
>the rapidly dividing ones remain mitochondrially healthy.  Our
>possession of (and reliance on) cell types which do not divide is,
>according to the mitochondrial theory
>of aging, the thing that renders us vulnerable.


Comment:

     Then all I can say is that it's a really stupidly named "theory."
If failure of cells to divide led to non-repair of membranes (which
otherwise happens in dividing cells), would you call this the
"membrane" theory of aging?  If failure of cells to divide led to non
repair of of DNA, would you call this the "DNA theory of aging?"   If
non division let to protein turnover problems and clinker enzymes,
would you refer to this as the error catastrophe theory of aging?

    Though all these mistakes have been made in gerontology, I hope you
would not perpetuate them, since in all cases it's clear that the
damage problem is secondary to the failure of repair, which in dividing
cells does not even exist.  Repair in many dividing cells is quite
sufficient for functional immortality, and I can hardly overemphasize
this point.  Thus, if failure of this repair process to keep up with
free radical damage in non-dividing cells leads to increasing free
radical damage, it's simply obfuscatory to refer to this as a "free
radical" theory of aging.  Free radicals are not the primary problem in
that case.  If your gardner doesn't spray for bugs and the bugs eat
your garden, you don't say you have a bug problem.  If you're
intelligent you realize that you have a gardener problem.  Go to
primary sources.  Since some cells deal with free radicals well enough
to be immortal, free radicals are not the primary cause of aging.  They
are intermediate cause of damage when the PRIMARY problem (whatever it
is) interfers with the repair systems which keep radical damage from
accumulating.

   Hope my position is now clear.

                                       Steve Harris, M.D.

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: sci.life-extension,sci.med.nutrition
Subject: Re: Experimentation shows Vitamin C inhibits telomerase?!
Date: 18 Aug 1998 02:43:03 GMT

In <35d959d5.206655828@nntp.ix.netcom.com> ufotruth@ix.netcom.com
writes:

>If turning the telomerase gene on in normal human cells increased the
>chance of cancer then it would be a major drawback in trying to
>reverse human aging.... I wonder if any other organizations, other
>than GERON, have confirmed that immortalizing cells with the
>telomerase gene makes them more likely to become cancerous.


   Last I heard, GERON was telling half their investors that more
telomerase would make you immortal, and the other have that new
telomerase inhibitors under development would be the answer to cancer.
ROFL.  Have to do this very delicately.

From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: misc.health.alternative,bionet.molbio.ageing,sci.med,
	sci.life-extension
Subject: Re: Cause of aging
Date: 18 Aug 1998 02:53:38 GMT

In <6r98va$8vc$1@pegasus.csx.cam.ac.uk> ag24@mole.bio.cam.ac.uk (Aubrey
de Grey) writes:

>I have plenty of sympathy with the above, but not with this:
>
>> in all cases it's clear that the
>> damage problem is secondary to the failure of repair
>
>This is not the case with the "mitochondrial theory of aging", at least
>not any more.  Formally, it's of course correct that if repair kept up
>with damage then we'd be OK, but the question (as James stresses) is
>whether that's achievable.

   Obviously it's achievable.  There are immortal plants (aspens) and
animals (corals, maybe even lobsters).  Their mitochondria obviously
don't give them any problems, and they don't get new ones from Mars.
Whether old mitochondria are repaired, or just produced anew and free
of defect at a sufficient pace, is immaterial.  For the cell, it's
repair either way.  Any process that makes new fresh cell organelles
counts as "cell repair" in my book.