The fountain of youth legend
goes back to the fifth century BC, appearing in writings by Herodotus,
but not until recently did scientists make a real breakthrough in
reversing aging.
The
Stuart Kim Lab of Stanford University School of Medicine has
successfully rejuvenated nematodes. Generally, nematodes live about 20
days. An 18-day-old nematode can hardly move, under normal
circumstances. However, the Stuart Kim Lab has managed to double a
nematode’s life span and make the 40-day-old stay as active as a
10-day-old!
“The
key to the nematode’s rejuvenation is ELT-3, a transcription factor
that regulates a large number of downstream genes,” said Dr. Stuart Kim,
professor of the departments of Developmental Biology and Genetics at
Stanford University.
Dr.
Kim explained that ELT-3 declines in the nematode with age, and that
subsequently leads to the degeneration of all the cells it regulates.
However, once ELT-3 is artificially enhanced in the lab, all the cells
are recharged, and the nematode regains its youth.
Can
the nematode experience be applied to human beings? According to Dr.
Kim, comparable mechanisms have been found in the human brain, heart,
muscles, and kidneys.
Wear & Tear vs. Developmental Drift
The
discoveries of the so-called “master regulators” in human beings
challenge the traditional view of aging which attributes its cause to
only wear and tear. The new theory of aging, developmental drift, states
that aging happens when master regulators become less functional and
organismal development goes awry.
To make the two theories easier to understand, Dr. Kim compares the human body to an automobile.
“An
old person doesn’t move very fast, just like an old car,” said Dr. Kim.
“The old theory says the car gets old because its parts are worn out,
but we think there’s more to it. We’ve found master regulators, each of
which can turn on or turn off hundreds of genes.”
“In
a car, the master regulator is the gas pedal,” he explained. “In
animals and people, the master regulators are transcription factors and
growth factors. It’s exciting to know these master regulators. Think
about it. With the wear and tear model, we cannot fix all the parts that
have been worn out. But if aging is just the gas pedal not being pushed
down hard enough, you can push it harder. It’s much easier to fix.”