Health is the most valuable thing we have in life, but we tend to forget that until we lose it.
We're living longer than ever before, which
is great, but an unforeseen consequence of this is that we also spend a larger and larger portion of our lives being sick.
Getting old currently means spending
more time in pain.
So scientists are trying to shift the attention of the medical community from optimizing lifespans to optimizing healthspans, the part of our lives during which we're disease free.
To do this, we need to attack the root
cause of almost all bodily defects: aging
itself.
Let's look at three examples of discoveries that might benefit people who are alive right now.
1 : Senescent cells.
Your cells have an expiration date. Each time one of your cells divides, it copies its chromosomes. Because of the way this works, they lose a tiny bit of DNA at the ends.
This could be catastrophic, so to protect
themselves we have long segments of
DNA called telomeres that sort of act like the stiff bits at the end of shoelaces, but they shrink with every cell division.
In some cells, after a number of divisions
the telomeres are gone, and the cell becomes a zombie, a senescent cell.
Senescent cells stay around and don't
die. The older you get the more of them
are inside you.
They harm tissue around them and are
linked to many diseases that accompany
old age like diabetes and kidney failure.
But what if you could kill them off?
Scientists genetically engineered mice so
that they could destroy their senescent
cells as they pleased.
Older mice without senescent cells were
more active. Their hearts and kidneys
worked better, and they were less prone
to cancer.
Overall, they lived up to 30 percent longer
and in better health than average mice.
Since we can't genetically engineer all the
cells in the human body, we need to find
another way to get rid of our senescent
cells.
But how do we kill them without harming
healthy cells?
Most cells in the body commit a programmed cell suicide when they're
damaged, but senescent cells don't.
It turns out that they underproduce a protein that tells them when it's time to
die.
So in a late 2016 study, mice were given
an injection of this protein.
It killed 80 % of all their senescent cells,
while causing almost no harm to healthy
cells.
The treated mice became generally healthier and even regrew lost hair.
As a result, there are a number of new
companies looking at treatments involving senescent cells and the first human trials will start soon.
2: NAD+
Cells are made of hundreds of millions of
parts.
They're the structures, machines,
messages, and the catalysts that make
reactions happen.
All these parts constantly need to be
destroyed, cleaned up, and rebuilt.
As we age, this process becomes less
effective and so parts become crumpled,
bunched up, or are removed slower, or they are no longer produced in the quantities we need.
One of these parts is NAD+, a coenzyme
that tells ourselves to look after
themselves.
At age 50, we only have about half as
much in our bodies as we do at age 20.
Low amounts of it are linked to a whole
bunch of diseases from skin cancer to
Alzheimer's, cardiovascular disease, and
multiple sclerosis.
But NAD+ can't enter cells so we can't get
it as a pill.
But scientists notice that other more
flexible substances could enter cells and
would then turn into an NAD+ inside.
In 201 6, multiple trials on mice showed
that they boosted the multiplication of
skin, brain, and muscle stem cells.
They were rejuvenated, had a higher
ability to repair their DNA, and had a
slightly increased lifespan, This even got NASA interested, which is looking for a way to minimize the DNA damage, astronauts would be exposed to from cosmic radiation on Mars missions.
There are human trials being planned
right now, but it's too soon to say if this will boost our healthspan or even lifespan.
But NAD+ is a serious candidate and
could become the first human anti-aging
pill.
3: stem cells
Stem cells are like cell blueprints that sit
at various places in the body and copy
themselves to produce a steady flow of
fresh young cells, but they decline as we age and so we decline too.
Without new parts, human bodies break.
In mice, scientists observed that as the
stem cells in their brains disappeared,
they started to develop diseases.
So they took stem cells from baby mice
brains and injected them directly into the
brains of middle-aged mice, more specifically the hypothalamus, a
polyp that's involved in regulating a lot of
bodily functions.
The fresh stem cells reinvigorated older
brain cells by secreting micro RNAs that
regulated their metabolism.
After 4 months, brain and muscles
worked better than those of untreated
mice and on average, they lived ten
percent longer.
Another study took stem cells from mice
embryos and injected them directly into
the hearts of older mice.
As a consequence, they had improved
heart function, could exercise 20% longer,
and weirdly enough their hair regrew
faster.
a single magic bullet with which to cure
aging.
It requires a complex array of different
therapies.
We can kill off senescent cells to clear
away the junk, give ourselves fresh new stem cells to fill the gap, all while regulating the metabolism of the other cells using
medication.
There's no guarantee the same therapies
would work in us to the same extent, but
they are proof of concepts.
To learn more about how we can modify
our own healthspan, we need human
trials.
We've only covered a tiny part of the
research that's being done right now,
and only scratched the surface of these
ideas.
The field of healthspan extension needs
more attention and funding.
If it gets it, all of us might enjoy growing
old without pain.
