I'm
determined to age gracefully. Though my wife plucks every gray hair she
finds, I'd be bald if I did. Even so, I've kept myself up over the
years, prompting my college girlfriend, whom I recently reconnected with
to exclaim, “You haven't aged at all!" Except for more gray hair, that
is. Perhaps it's just good genes. I've always chalked it up to
stress-free living. So what can be done to overcome the aging process?
Creams, lotions, and other products fill pharmacy shelves, but few have a
truly substantial impact.
Now, researchers at the Salk Institute
in La Jolla, California have discovered a way to turn back the hands of
time. Juan Carlos Izpisua Belmonte led this study, published in the
journal Cell.
Here, elderly mice underwent a new sort of gene therapy for six weeks.
Afterward, their injuries healed, their heart health improved, and even
their spines were straighter. The mice also lived longer, 30% longer.
Today,
we target individual age-related diseases when they spring up. But this
study could help us develop a therapy to attack aging itself, and
perhaps even target it before it begins taking shape. But such a therapy
is at least ten years away, according to Izpisua Belmonte.
Many
biologists now believe that the body, specifically the telomeres—the
structures at the end of chromosomes, after a certain time simply wear
out. Once degradation overtakes us, it's the beginning of the end. This
study strengthens another theory. Over the course of a cell's life,
epigenetic changes occur. This is the activation or depression of
certain genes in order to allow the organism to respond better to its
environment. Methylation tags are added to activate genes. These changes
build up over time, slowing us down, and making us vulnerable to
disease.
Chromosomes with telomeres in red.
Though
we may add life to years, don't consider immortality an option, at
least not in the near-term. “There are probably still limits that we
will face in terms of complete reversal of aging," Izpisua Belmonte
said. “Our focus is not only extension of lifespan but most importantly
health-span." That means adding more healthy years to life, a noble
prospect indeed.
The technique
employs induced pluripotent stem cells (iPS). These are similar to those
which are present in developing embryos. They are important as they can
turn into any type of cell in the body. The technique was first used to
turn back time on human skin cells, successfully.
By switching around four essential genes, all active inside the womb, scientists were able to turn skin cells into iPS cells.
These four genes are known as Yamanaka factors. Scientists have been
aware of their potential in anti-aging medicine for some time. In the
next leg, researchers used genetically engineered mice who could have
their Yamanaka factors manipulated easily, once they were exposed to a
certain agent, present in their drinking water.
Since
Yamanaka factors reset genes to where they were before regulators came
and changed them, researchers believe this strengthens the notion that
aging is an accumulation of epigenetic changes. What's really exciting
is that this procedure alters the epigenome itself, rather than having
the change the genes of each individual cell.
The mechanics of epigenetics.
In
another leg of the experiment, mice with progeria underwent this
therapy. Progeria is a disease that causes accelerated aging. Those who
have seen children who look like seniors know the condition. It leads to
organ damage and early death. But after six months of treatment, the
mice looked younger. They had better muscle tone and younger looking
skin, and even lived around 30% longer than those who did not undergo
the treatment.
Luckily for the mice,
time was turned back the appropriate amount. If turned back too far,
stem cells can proliferate in an uncontrolled fashion, which could lead
to tumor formation. This is why researchers have been reticent to
activate the Yamanaka factors directly. However, these scientists
figured out that by intermittently stimulating the factors, they could
reverse the aging process, without causing cancer. The next decade will
concentrate on perfecting this technique.
Since
the threat of cancer is great, terminally ill patients would be the
first to take part in a human trial, most likely those with progeria.
Unfortunately, the method used in this study could not directly be
applied to a fully functioning human. But researchers believe a drug
could do the job, and they are actively developing one.
“This
study shows that aging is a very dynamic and plastic process, and
therefore will be more amenable to therapeutic interventions than what
we previously thought," Izpisua Belmonte said. Of course, mouse systems
and human one's are far different. This only gives us an indication of
whether or not it might work. And even if it does, scientists will have
to figure out how far to turn back the clock. But as Izpisua Belmonte
said, “With careful modulation, aging might be reversed."
