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Good afternoon.
There's a medical revolution happening all around us,
and it's one that's going to help us conquer
some of society's most dreaded conditions,
including cancer.
The revolution is called angiogenesis,
and it's based on the process
that our bodies use to grow blood vessels.
So why should we care about blood vessels?
Well, the human body is literally packed with them:
60,000 miles worth in a typical adult.
End to end, that would form a line
that would circle the earth twice.
The smallest blood vessels are called capillaries;
we've got 19 billion of them in our bodies.
And these are the vessels of life, and,
as I'll show you,
they can also be the vessels of death.
Now the remarkable thing about blood vessels
is that they have this ability
to adapt to whatever environment they're growing in.
For example, in the liver they form channels
to detoxify the blood;
in the lung they line air sacs for gas exchange;
in muscle they corkscrew so that muscles can contract
without cutting off circulation;
and in nerves they course along like power lines,
keeping those nerves alive.
We get most of these blood vessels
when we're actually still in the womb,
And what that means is that as adults,
blood vessels don't normally grow.
Except in a few special circumstances:
In women, blood vessels grow every month
to build the lining of the uterus;
during pregnancy, they form the placenta,
which connects mom and baby.
And after injury, blood vessels
actually have to grow under the scab
in order to heal a wound.
And this is actually what it looks like,
hundreds of blood vessels
all growing toward the center of the wound.
So the body has the ability to regulate
the amount of blood vessels that are present at any given time.
It does this through an elaborate
and elegant system of checks and balances,
stimulators and inhibitors of angiogenesis,
such that, when we need a brief burst of blood vessels,
the body can do this by releasing stimulators,
proteins called angiogenic factors
that act as natural fertilizer
and stimulate new blood vessels to sprout.
And when those excess vessels are no longer needed,
the body prunes them back to baseline
using naturally occurring inhibitors of angiogenesis.
Now there are other situations where we start beneath the baseline
and we need to grow more blood vessels just to get back to normal levels --
for example, after an injury --
and a body can do that too,
but only to that normal level,
that set point.
But what we now know is that for a number of diseases,
there are defects in the system
where the body can't prune back extra blood vessels
or can't grow enough new ones
in the right place at the right time.
And in these situations, angiogenesis
is out of balance.
And when angiogenesis is out of balance,
a myriad of diseases result.
For example, insufficient angiogenesis --
not enough blood vessels --
leads to wounds that don't heal, heart attacks,
legs without circulation, death from stroke,
nerve damage.
And on the other end, excessive angiogenesis --
too many blood vessels -- drives disease,
and we see this in cancer, blindness,
arthritis, obesity,
Alzheimer's disease.
In total, there are more than 70 major diseases
affecting more than a billion people worldwide,
that all look on the surface to be different from one another,
but all actually share
abnormal angiogenesis
as their common denominator.
And this realization is allowing us
to reconceptualize
the way that we actually approach these diseases
by controlling angiogenesis.
Now I'm going to focus on cancer
because angiogenesis is a hallmark of cancer,
every type of cancer.
So here we go.
This is a tumor: dark, gray, ominous mass
growing inside a brain.
And under the microscope, you can see
hundreds of these brown staining blood vessels,
capillaries that are feeding cancer cells,
bringing oxygen and nutrients.
But cancers don't start out like this.
And, in fact, cancers don't start out
with a blood supply.
They start out as small, microscopic nests of cells
that can only grow to
one half a cubic millimeter in size;
that's the tip of a ballpoint pen.
Then they can't get any larger because they don't have a blood supply,
so they don't have enough oxygen or nutrients.
In fact, we're probably forming these
microscopic cancers all the time in our body.
Autopsy studies from people who died in car accidents
have shown that about 40 percent of women
between the ages of 40 and 50
actually have microscopic
cancers in their breasts,
about 50 percent of men in their 50s and 60s
have microscopic prostate cancers,
and virtually 100 percent of us,
by the time we reach our 70s,
will have microscopic cancers growing in our thyroid.
Yet, without a blood supply,
most of these cancers
will never become dangerous.
Dr. Judah Folkman, who was my mentor
and who was the pioneer of the angiogenesis field,
once called this "cancer without disease."
So the body's ability to balance angiogenesis,
when it's working properly,
prevents blood vessels from feeding cancers.
And this turns out to be
one of our most important defense mechanisms
against cancer.
In fact, if you actually block angiogenesis
and prevent blood vessels from ever reaching cancer cells,
tumors simply can't grow up.
But once angiogenesis occurs,
cancers can grow exponentially.
And this is actually how
a cancer goes from being
harmless to deadly.
Cancer cells mutate
and they gain the ability to release
lots of those angiogenic factors, natural fertilizer,
that tip the balance in favor of blood vessels
invading the cancer.
And once those vessels invade the cancer,
it can expand, it can invade local tissues.
And the same vessels that are feeding tumors
allow cancer cells to exit into the circulation
as metastases.
And, unfortunately, this late stage of cancer
is the one at which it's most likely
to be diagnosed,
when angiogenesis is already turned on
and cancer cells are growing like wild.
So, if angiogenesis
is a tipping point
between a harmless cancer and a harmful one,
then one major part of the angiogenesis revolution
is a new approach to treating cancer
by cutting off the blood supply.
We call this antiangiogenic therapy,
and it's completely different from chemotherapy
because it selectively aims
at the blood vessels that are feeding the cancers.
And we can do this because
tumor blood vessels are unlike normal, healthy vessels
we see in other places of the body:
They're abnormal;
they're very poorly constructed;
and, because of that, they're highly vulnerable
to treatments that target them.
In effect, when we give cancer patients
antiangiogenic therapy --
here, an experimental drug for a glioma,
which is a type of brain tumor --
you can see that there are dramatic changes that occur
when the tumor is being starved.
Here's a woman with a breast cancer
being treated with the antiangiogenic drug called Avastin,
which is FDA approved.
And you can see that the halo of blood flow
disappears after treatment.
Well, I've just shown you
two very different types of cancer
that both responded to antiangiogenic therapy.
So, a few years ago, I asked myself,
"Can we take this one step further
and treat other cancers,
even in other species?"
So here is a nine year-old boxer named Milo
who had a very aggressive tumor
called a malignant neurofibroma growing on his shoulder.
It invaded into his lungs.
His veterinarian only gave him three months to live.
So we created a cocktail of antiangiogenic drugs
that could be mixed into his dog food
as well as an antiangiogenic cream
that could be applied on the surface of the tumor.
And within a few weeks of treatment,
we were able to slow down that cancer's growth
such that we were ultimately able to extend milo's survival
to six times what the veterinarian had initially predicted,
all with a very good quality of life.
And we subsequently treated more than 600 dogs.
We have about a 60 percent response rate
and improved survival for these pets
that were about to be euthanized.
So let me show you a couple of
even more interesting examples.
This is 20-year-old dolphin living in Florida,
and she had these lesions in her mouth
that, over the course of three years,
developed into invasive squamous cell cancers.
So we created an antiangiogenic paste.
We had it painted on top of the cancer
three times a week.
And over the course of seven months,
the cancers completely disappeared,
and the biopsies came back as normal.
Here's a cancer growing on the lip
of a Wuarter horse named Guinness.
It's a very, very deadly type of cancer called an angiosarcoma.
It had already spread to his lymph nodes,
so we used an antiangiogenic skin cream for the lip
and an oral cocktail, so we could treat from the inside
as well as the outside.
And over the course of six months,
he experienced a complete remission.
And here he is six years later,
Guinness, with his very happy owner.
(Applause)
Now, obviously, antiangiogenic therapy
could be used for a wide range of cancers.
And, in fact, the first pioneering treatments
for people, as well as dogs,
are already becoming available.
There's 12 different drugs, 11 different cancer types.
But the real question is:
How well do these work in practice?
So here's actually the patient survival data
from eight different types of cancer.
The bars represent survival time
taken from the era
in which there was only chemotherapy,
or surgery, or radiation available.
But starting in 2004,
when antiangiogenic therapies first became available,
well you can see that there has been
a 70 to 100 percent
improvement in survival
for people with kidney cancer, multiple myeloma,
colorectal cancer, and gastrointestinal stromal tumors.
That's impressive.
But for other tumors and cancer types,
the improvements have only been modest.
So I started asking myself,
"Why haven't we been able to do better?"
And the answer, to me, is obvious;
we're treating cancer too late in the game,
when it's already established
and, oftentimes, it's already spread or metastasized.
And as a doctor, I know
that once a disease progresses to an advanced stage,
achieving a cure
can be difficult, if not impossible.
So I went back to the biology
of angiogenesis
and started thinking:
Could the answer to cancer
be preventing angiogenesis,
beating cancer at its own game
so the cancers could never become dangerous?
This could help healthy people
as well as people who've already beaten cancer
once or twice
and want to find a way to keep it from coming back.
So to look for a way to prevent angiogenesis in cancer,
I went back to look at cancer's causes.
And what really intrigued me
was when I saw that diet
accounts for 30 to 35 percent
of environmentally caused cancers.
Now, the obvious thing is to think about
what we could remove from our diet, what to strip out, take away.
But I actually took a completely opposite approach
and began asking: What could we be adding to our diet
that's naturally antiangiogenic,
that could boost the body's defense system
and beat back those blood vessels that are feeding cancers?
In other words, can we eat to starve cancer? (Laughter)
Well, the answer's yes,
and I'm going to show you how.
Our search for this
has taken us to the market, the farm and to the spice cabinet,
because what we've discovered
is that mother nature has laced a large number
of foods and beverages and herbs
with naturally occurring inhibitors
of angiogenesis.
So here's a test system we developed.
At the center is a ring from which hundreds of blood vessels
are growing out in a starburst fashion.
And we can use this system
to test dietary factors
at concentrations that are obtainable by eating.
So let me show you what happens when we put in
an extract from red grapes.
The active ingredient's resveratrol,
it's also found in red wine.
This inhibits abnormal angiogenesis
by 60 percent.
Here's what happens when we added an extract from strawberries;
it potently inhibits angiogenesis.
And extract from soybeans.
And here is a growing list of our
antiangiogenic foods and beverages
that we're interested in studying.
For each food type,
we believe that there are different potencies
within different strains and varietals.
And we want to measure this because,
well, while you're eating a strawberry
or drinking tea,
why not select the one that's most potent
for preventing cancer.
So here are four different teas that we've tested.
They're all common ones:
Chinese jasmine, Japanese sencha,
Earl Grey and a special blend that we prepared.
And you can see clearly
that the teas vary in their potency
from less potent to more potent.
But what's very cool
is when we actually combined the two
less potent teas together,
the combination, the blend,
is more potent than either one alone.
This means there's food synergy.
Here's some more data from our testing.
Now, in the lab, we can simulate tumor angiogenesis
represented here in a black bar.
And using this system, we can test the potency of cancer drugs.
So the shorter the bar,
less angiogenesis, that's good.
And here are some common drugs
that have been associated with reducing the risk
of cancer in people.
Statins, nonsteroidal anti-inflammatory drugs
and a few others,
they inhibit angiogenesis too.
And here are the dietary factors
going head to head against these drugs.
You can see, they clearly hold their own
and, in some cases, they're more potent
than the actual drugs.
Soy, parsley, garlic,
grapes, berries;
I could go home and cook a tasty meal
using these ingredients.
So imagine if we could create
the world's first rating system
in which we could score foods
according to their antiangiogenic,
cancer-preventative properties.
And that's what we're doing right now.
Now, I've shown you a bunch of lab data,
and so the real question is:
What is the evidence in people
that eating certain foods can reduce
angiogenesis in cancer?
Well, the best example I know
is a study of 79,000 men
followed over 20 years,
in which it was found that men who consumed
cooked tomatoes two to three times a week
had up to a 50 percent reduction
in their risk of developing prostate cancer.
Now, we know that tomatoes are a good source of lycopene,
and lycopene is antiangiogenic.
But what's even more interesting from this study
is that in those men who did develop prostate cancer,
those who ate more servings of tomato sauce
actually had fewer blood vessels
feeding their cancer.
So this human study is a prime example
of how antiangiogenic substances
present in food and consumed at practical levels
can impact on cancer.
And we're now studying
the role of a healthy diet
with Dean Ornish at UCSF and Tufts University
on the role of this healthy diet on markers of angiogenesis
that we can find in the bloodstream.
Now, obviously, what I've shared with you has some far-ranging implications,
even beyond cancer research.
Because if we're right, it could impact on consumer education,
food services, public health
and even the insurance industry.
And, in fact, some insurance companies
are already beginning to think along these lines.
Check out this ad from Blue Cross Blue Shield of Minnesota.
And for many people around the world,
dietary cancer prevention
may be the only practical solution
because not everybody can afford expensive end-stage cancer treatments,
but everybody could benefit from
a healthy diet based on local, sustainable,
antiangiogenic crops.
Now, finally,
I've talked to you about food,
and I've talked to you about cancer,
so there's just one more disease that I have to tell you about
and that's obesity.
Because it turns out that
adipose tissue, fat,
is highly angiogenesis dependent.
And, like a tumor, fat grows when blood vessels grow.
So the question is: Can we shrink fat
by cutting off its blood supply?
So the top curve shows the body weight
of a genetically obese mouse
that eats nonstop
until it turns fat, like this furry tennis ball.
And the bottom curve is the weight of a normal mouse.
If you take the obese mouse and give it
an angiogenesis inhibitor, it loses weight.
Stop the treatment, gains the weight back.
Restart the treatment, loses the weight again.
Stop the treatment, it gains the weight back.
And, in fact, you can cycle the weight up and down
simply by inhibiting angiogenesis.
So this approach that we're taking for cancer prevention
may also have an application
for obesity.
The really, truly interesting thing about this
is that we can't take these obese mice
and make them lose more weight
than what the normal mouse's weight is supposed to be.
In other words, we can't create supermodel mice.
(Laughter)
And this speaks to the role of angiogenesis
in regulating healthy set points.
Albert Szent-Gyorgi once said that,
"Discovery consists of seeing what everyone has seen,
and thinking what no one has thought."
I hope I've convinced you
that, for diseases like cancer, obesity and other conditions,
that there may be a great power
in attacking their common denominator: angiogenesis.
And that's what I think the world needs now. Thank you.
(Applause)
June Cohen: I have a quick question for you. So these drugs aren't exactly ...
they're not exactly in mainstream cancer treatments right now.
For anyone out here who has cancer,
what would you recommend?
Do you recommend pursuing these treatments now, for most cancer patients?
William Li: So there are antiangiogenic treatments
that are FDA approved,
and if you're a cancer patient
or working for one or advocating for one,
you should ask about them.
And there are many clinical trials.
The Angiogenesis Foundation is following almost 300 companies,
and there are about 100 more
drugs in that pipeline.
So consider the approved ones,
look for clinical trials,
but then between what the doctor can do for you,
we need to start asking what can we do for ourselves.
And this is one of the themes that I'm talking about
is we can empower ourselves to do the things
that doctors can't do for us,
which is to use knowledge and take action.
And if Mother Nature has given us some clues,
we think that there might be a new future
in the value of how we eat.
And what we eat is really our chemotherapy three times a day.
JC: Right. And along those lines,
for people who might have risk factors for cancer,
would you recommend pursuing any treatments sort of prophylactically
or simply pursuing the right diet
with lots of tomato sauce?
WL: Well, you know, there's abundant epidemiological evidence.
And I think in the information age,
it doesn't take long to go to a credible source
like PubMed, the National Library of Medicine,
to look for epidemiological studies
for cancer risk reduction
based on diet and based on common medications.
And that's certainly something that anybody can look into.
JC: Okay. Well, thank you so much.
(Applause)
コツ:単語をクリックしてすぐ意味を調べられます!

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【TED】ウィリアム・リー: 癌が消滅する食し方 (Can we eat to starve cancer? | William Li)

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VoiceTube 2013 年 7 月 10 日 に公開
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