technologyreview | Izpisúa Belmonte believes epigenetic
reprogramming may prove to be an “elixir of life” that will extend human
life span significantly. Life expectancy has increased more than
twofold in the developed world over the past two centuries. Thanks to
childhood vaccines, seat belts, and so on, more people than ever reach
natural old age. But there is a limit to how long anyone lives, which
Izpisúa Belmonte says is because our bodies wear down through inevitable
decay and deterioration. “Aging,” he writes, “is nothing other than
molecular aberrations that occur at the cellular level.” It is, he says,
a war with entropy that no individual has ever won.
But each generation
brings new possibilities, as the epigenome gets reset during
reproduction when a new embryo is formed. Cloning takes advantage of
reprogramming, too: a calf cloned from an adult bull contains the same
DNA as the parent, just refreshed. In both cases, the offspring is born
without the accumulated “aberrations” that Izpisúa Belmonte refers to.
What
Izpisúa Belmonte is proposing is to go one step better still, and
reverse aging-related aberrations without having to create a new
individual. Among these are changes to our epigenetic marks—chemical
groups called histones and methylation marks, which wrap around a cell’s
DNA and function as on/off switches for genes. The accumulation of
these changes causes the cells to function less efficiently as we get
older, and some scientists, Izpisúa Belmonte included, think they could
be part of why we age in the first place. If so, then reversing these
epigenetic changes through reprogramming may enable us to turn back
aging itself.
Izpisúa Belmonte cautions
that epigenetic tweaks won’t “make you live forever,” but they might
delay your expiration date. As he sees it, there is no reason to think
we cannot extend human life span by another 30 to 50 years, at least. “I
think the kid that will be living to 130 is already with us,” Izpisúa
Belmonte says. “He has already been born. I’m convinced.”
