00:00Health is the most valuable thing we have in life, but we tend to forget that until we lose it.
00:07We're living longer than ever before, which is great.
00:10But an unforeseen consequence of this is that we also spend a larger and larger portion of our lives being sick.
00:17Getting old currently means spending more time in pain.
00:21So scientists are trying to shift the attention of the medical community from optimizing life spans to optimizing health spans.
00:29The part of our lives during which we're disease-free.
00:33To do this, we need to attack the root cause of almost all bodily defects, aging itself.
00:39Unbeknown to most people, the science of aging has made enormous progress in the last few years, with human trials about to begin in the near future.
00:47Let's look at three examples of discoveries that might benefit people who are alive right now.
00:53One, senescent cells.
00:57Your cells have an expiration date.
01:00Each time one of your cells divides, it copies its chromosomes.
01:04Because of the way this works, they lose a tiny bit of DNA at the ends.
01:08This 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.
01:17But they shrink with every cell division.
01:20In some cells, after a number of divisions, the telomeres are gone and the cell becomes a zombie.
01:26A senescent cell.
01:28Senescent cells stay around and don't die.
01:31The older you get, the more of them there are inside you.
01:34They harm tissue around them and are linked to many diseases that accompany old age, like diabetes and kidney failure.
01:42But what if you could kill them off?
01:45Scientists genetically engineered mice so that they could destroy their senescent cells as they pleased.
01:51Older mice without senescent cells were more active.
01:54Their hearts and kidneys worked better and they were less prone to cancer.
01:58Overall, they lived up to 30% longer and in better health than average mice.
02:03Since we can't genetically engineer all of the cells in the human body, we need to find another way to get rid of our senescent cells.
02:10But how do we kill them without harming healthy cells?
02:14Most cells in the body commit a programmed cell suicide when they're damaged.
02:19But senescent cells don't.
02:21It turns out that they underproduce a protein that tells them when it's time to die.
02:26So, in a late 2016 study, mice were given an injection of this protein.
02:31It killed 80% of all their senescent cells while causing almost no harm to healthy cells.
02:37The treated mice became generally healthier and even re-grew lost hair.
02:42As a result, there are a number of new companies looking at treatments involving senescent cells and the first human trials will start soon.
02:512. NAD+.
02:54Cells are made from hundreds of millions of parts.
02:57They're the structures, machines, messages and the catalysts that make reactions happen.
03:03All these parts constantly need to be destroyed, cleaned up and rebuilt.
03:08As we age, this process becomes less effective and so parts become crumpled, bunched up or are removed slower.
03:15Or they are no longer produced in the quantities we need.
03:19One of these parts is NAD+, a coenzyme that tells our cells to look after themselves.
03:25At age 50, we only have about half as much in our bodies as we do at age 20.
03:31Low amounts of it are linked to a whole bunch of diseases from skin cancer to Alzheimer's, cardiovascular disease and multiple sclerosis.
03:39But NAD++ can't enter cells, so we can't get it as a pill.
03:44But scientists noticed that other, more flexible substances could enter cells and would then turn into NAD+.
03:51In 2016, multiple trials on mice showed that they boosted the multiplication of skin, brain and muscle stem cells.
03:59They were rejuvenated, had a higher ability to repair their DNA and had a slightly increased lifespan.
04:06This 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.
04:15There are human trials being planned right now, but it's too soon to say if this will boost our healthspan or even lifespan.
04:22But NAD++ is a serious candidate and could become the first human anti-aging pill.
04:293. Stem cells
04:32Stem 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.
04:40But they decline as we age, and so we decline too.
04:44Without new parts, human bodies break.
04:48In mice, scientists observed that as the stem cells in their brains disappeared, they started to develop diseases.
04:55So they took stem cells from baby mice brains and injected them directly into the brains of middle-aged mice.
05:02More specifically, the hypothalamus, a part that's involved in regulating a lot of bodily functions.
05:08The fresh stem cells reinvigorated older brain cells by secreting microRNAs that regulated their metabolism.
05:15After four months, brain and muscles worked better than those of untreated mice and, on average, they lived 10% longer.
05:23Another study took stem cells from mice embryos and injected them directly into the hearts of older mice.
05:30As a consequence, they had improved heart function, could exercise 20% longer, and, weirdly enough, their hair regrew faster.
05:43What all of this tells us is that there is not a single magic bullet with which to cure aging.
05:48It requires a complex array of different therapies.
05:52We can kill off senescent cells to clear away the junk, give ourselves fresh new stem cells to fill the gap,
05:57all while regulating the metabolism of the other cells using medication.
06:02This video comes with a big caveat.
06:05After all, these studies have been carried out on mice.
06:08There's no guarantee the same therapies would work in us to the same extent, but they are proof of concepts.
06:15To learn more about how we can modify our own health span, we need human trials.
06:20We've only covered a tiny part of the research that's being done right now and only scratched the surface of these ideas.
06:26The field of health span extension needs more attention and funding.
06:30If it gets it, all of us might enjoy growing old without pain.
