Re: Enzyme takes us a step closer to eternal youth (New Scientist)

[Guest guest]

There has been a poster to alt.sci.life-ext and I think also this group

(years ago), who wrote by the name Effros. So when I had first read

this story I wondered if it was the same Effros as the scientist

referenced in this study. I suspect one and the same based on quality

of information posted. Anyone gone out to buy astragalus yet?

alistair tweed wrote:

>

> Enzyme takes us a step closer to eternal youth

> * 19 November 2008 by Geddes

>

> COULD artificially raising levels of a key enzyme hold back the

> effects of ageing? It has long been a hope but now two lab experiments

> - one with human cells and one in animals - are providing the first

> evidence that this may actually be possible.

> The

> enzyme in question is telomerase, which is present naturally in some

> mammalian cells. Its function is to maintain the protective caps

> called telomeres at the ends of our chromosomes, which unravel with

> each cell division

> as we get older. It has been suggested that this shortening triggers

> some of the negative effects of ageing at a cellular level. As a

> result, telomerase has been hailed by some as a potential elixir of life.

> One

> of the latest studies confirms that at least one type of human cell can

> indeed be restored to a youthful state by boosting telomerase levels.

> The other suggests that boosting telomerase can result in longer life

> in animals. While an elixir of life in people remains a very long way

> off, the prospect of boosting telomerase to fight disease, including

> age-related diseases, may be much closer.

> With the aim of fighting HIV, immunologist Rita Effros at the

> University of California, Los Angeles, previously inserted part

> of the telomerase gene into immune cells called killer T-cells. While

> this did indeed boost their ability to fight viral infections, such

> gene therapy is considered too dangerous to be used in practice.

> So in her latest experiments, Effros has turned to a drug called TAT2,

> developed by Geron of Menlo Park, California, that boosts telomerase

> production without

> altering anyone's DNA.. When killer T-cells from people with HIV were

> exposed to TAT2, it enhanced the cells' ability to fight the virus,

> suggesting that TAT2 might be used to supplement existing

> anti-retroviral drugs by boosting the immune systems of people with HIV

> (The Journal of Immunology, vol 181, p 7400).

> This

> idea is supported by a previous study which indicated that some people

> with HIV who go for years without developing AIDS have killer T-cells

> with high telomerase activity and longer telomeres. Since T-cells fight

> many viruses, TAT2 might eventually be deployed to boost resistance to

> a whole range of diseases.

> TAT2

> also increased the cells' ability to divide and stopped their telomeres

> from shortening, which raises the possibility that it might be used to

> wind back the clock of other ageing cells and provide more general

> treatments for ageing.

> Aubrey de Grey of the Virginia-based Methuselah Foundation,

> which promotes research into extending lifespan, certainly sees the

> study as a big step in that direction. " It is what we would have

> hoped, " he says. He is particularly interested in the fact that the

> cells seemed to be " fully functional " in their new role as youthful

> immune cells, raising hopes that telomerase might wind back the

> cellular clock more generally.

> Some safety concerns remain, however, not least because cancer cells

> produce telomerase at higher than normal rates.

> " With anything that boosts telomerase, you may have unwanted cell

> growth like in cancers, " says Arne Akbar, an immunologist at University

> College London.

> However,

> when TAT2 was added to tumour cells it did not affect the amount of

> telomerase they produced. Nor did it change the growth characteristics

> of immune cells that were cultured with a virus that can trigger

> cancer. " We are fairly confident at this point that TAT2 won't enhance

> cancer development, " says Effros, although further trials are needed to

> confirm this.

> Telomerase is extracted from the Astragalus plant, which is used in

> Chinese medicine without any obvious adverse

> effects. While this may help pave the way to pilot studies in humans in

> the near future, Effros warns against taking large doses of Astragalus

> to try and mimic the TAT2 effect. " Uncontrolled use of any herbal drug

> is not wise and I would not advocate it, " she says.

> Even

> if telomerase proves successful at holding back some of the effects of

> ageing at a cellular level, it is still a big jump from there to

> something that stops a person as a whole from ageing. Yet this prospect

> too has been brought a step closer with an announcement last week from

> Blasco at the Spanish National Cancer Centre in Madrid and her

> colleagues.

> Telomerase

> has previously been shown capable of turning " a normal, mortal cell

> into an immortal cell " , as Blasco puts it. But whether this translates

> into delaying ageing in live mammals has previously been difficult to

> test, as high levels of telomerase tend to promote cancer, which

> shortens their lives.

> So

> Blasco's team bred mice engineered to be resistant to cancer with mice

> engineered to produce 10 times the normal levels of telomerase in

> epithelial tissue, which lines the cavities and surfaces of the body.

> These animals lived up to 50 per cent longer than normal mice (Cell,

> DOI: 10.1016/j.cell.2008..09.034). " You can delay the ageing of mice

> and increase their lifespan, " says Blasco.

> Blasco's

> mice also had less subcutaneous fat, healthier epithelial tissue and

> improved neuromuscular coordination and glucose tolerance, which are

> all signs of youth. Boosting telomerase also seemed to have beneficial

> effects on the animals' brains and muscles, even though the enzyme was

> not expressed in these tissues.

> Effros

> warns against concluding that this means we can prevent ageing in

> humans. " I think it is very hard to extrapolate data from mouse ageing

> to human ageing, " she says. In particular, she points out that all mice

> have longer telomeres than humans, and the lab mice are bred in sterile

> conditions.

> Blasco,

> however, is optimistic that a similar approach may eventually extend

> human lifespans. She suggests that the treatment could be combined with

> cancer drugs to offset any enhanced cancer risk.

> " We're

> learning to control cell division in a manner that gets the best of

> both worlds, " says de Grey, " allowing it to happen when we need it, and

> not to happen when we don't. "

> We're getting the best of both worlds - allowing cell division to

> happen when we need it but not to happen when we don't

> http://aging-management.com/ <http://aging-management.com/> -

> Optimising Health for Longevity

>

>