cc
our PLATO Frontiers in Life >> TSciences presentation. to
Today's speaker is Gary Lyons.
Anatomy here at UW-Madison. And he's also with the new Stem
Cell and Regenerative Medicine
recently. He'll be talking about heart
disease and cardiac stem cells. Please join me in welcoming Gary
Lyons to the PLATO series.
It's a pleasure to be here. I'm glad Tom was actually
outside and helped me find where
Otherwise, I'd probably still be this is.
get very worried. So I'm a professor in Anatomy in
the School of Medicine and
I'm not an MD, so I can not answer any of your clinical
questions.
heart, less about heart disease. But I know quite a bit about the
cells, and how those stem cells might be useful in current
studies that are ongoing
And also, we'll discuss a little clinical trials.
possibilities for using stem bit about what are the future
heart. cells to help regenerate the
heart disease is the leading So you may be well aware that
and in fact around the world. And unfortunately, approximately
every 45 seconds in this
heart disease. country, someone succumbs to
health problem in our society. So this is obviously a major
able to do is to, using various Amethods, such as behaviorbe
modification and certainly
these numbers so it's no longer as prevalent a problem as it isn
at the moment.
deaths from heart disease have The good news is that over all,
These particular numbers are decreased.
It was found that cardiovascular from 1993 to 2003.
about 22%. disease death rates dropped
Statins, yes. But it's smoking actually,
convincing people not to smoke
difference in cardiovascular has made this much of a
So what are the causes of heart disease ratdisease?is country.
What are the risk factors?
nothing about. Well, there are things we can do
are the genetic factors, the The things that we cannot change
parents. genes that we inherit from our
history of cardiovascular I'm come frdisease.ily with a
My father's mother died of a
My Aunt had a heart attack, and fortunately didn't die from it.
My dad died from a ruptured aneurysm.
So all of these things, we
And of course, with increasing cannot escape.
And I apologize, gentlemen, but we're at much greater risk than
women are, particularly in
disease. advanced age, for having heart
can change that will reduce our risk of having heart disease.
We can avoid high cholesterol.
mentioned. These are the statins that were
our society. These are very prevalent now in
at the moment. Half of my family is on Lipitor
also inherited from my dad. That can be treated in a couple
of ways.
exercise. But if that doesn't work, you
can also take medications that
by reducing your blood volume. will reduce your blood pressure
Diabetes, unfortunately if you That is, diuresis and diuretics.
risk of heart disease. have it, it will increase your
And diet, a high fat diet, and Smoking, definitely do not.
presently obese, this is a certainly in people who are
Carrying around the extra weight significant strain on the heart.
ultimately heart disease down leads to cathe road.ertrophy and
Don't be a couch potato, because
exercise, even just walking if you garound.there and
This is a good reason to have a dog.
If the dog has to go out and
It's a very good idea. walk around, then so do you.
assure you that that's a good Being a dog othing.yself, I can
A little bit of alcohol is a
A lot of alcohol is a bad thing. good thing.
two drinks per day, will So it's on the order of one to
heart disease. actually reduce your risk of
that, that can be a real But if you drink a lot more than
And then something else that we face every day in our society is
stress. And stress will increase your
risk of getting heart disease.
many different things help to So you relieve stress.xercise,
So these are the things that we can change.
And these the things that we
And throughout my talk, you'll cannot change.
that are very useful. The American Heart Association
has been a very strong
public, raising funds, making proponenpeople aware.t to the
Their big drive now is to make
heart disease. women aware of their risks for
disease, what are we actually So whentalking about? heart
Well, most of us, when we think of heart disease, think of
coronary heart disease. And this is something that most
of us are aware of. It's fairly routinely on
television. It's available to you on the
Internet. Information about
atherosclerosis, the presence of
artery walls that ultimately fatty deposits in your coronary
or a blockage, which leads to bthe cutting off of blood flown
from a certain area of the
This is what I refer to as acute heart.
up silently within you and then hall of a sudden, you have thiss
major chest pain, or you don't
And that's the onset of a heart feel attack.ight.
Other types of heart disease I
These are long-term problems. The most common of these is a
cardiomyopathy called Dilated Cardiomyopathy.
So the function, the heart, in
blood around the body, has to ohave a very strong wall, which
contracts regularly from about
through your very last day. And it normally has ventricles
that are a certain size.
muscle and the size of the And the combination of the
efficient organ for pumping ventriclesblood. it a very
As you can guess from the adjective "dilated," that what
has happened here is the
significantly. ventricles have expanded
the walls of the ventricles have And the other problem is that
makes the heart much less tefficient in terms of itsch
necessary function. That then, leads to lots of
other problems. Also within this category, we
can put ischemic heart disease. So ischemia refers to an area of
the heart that has been cut off from blood.
And basically, that is becoming connective tissue, rather than
healthy functioning muscle. And congestive heart failure
refers to a particular long-term
up of fluid in the body. problem which leads to a build
surprisingly enough, with It camedication.lled,
These are the things that we
heart disease or cardiovascular think about disease.think about
But this is just a very brief list.
If you want more information, go
Look up WebMD. to the Internet.
Association Web site. There are actually a very large
number of very good, well informed Web sites that will
give you all of the information that you'd be interested in.
So this is one example of cardiomyopathy.
At the top, we have a normal
ventricles and atria opened up, and also the aorta and pulmonary
artery. And you can see that the walls
are nice and thick and robust.
at the volume here of the And there ventricles.vely, look
Compare that down to the bottom,
ventricles. Notice the thinning walls.
This is part of the problem.
show you a little cartoon of Now if it works, I'm going to
builds up over time, leading to what we call a heart attack or
MI, a myocardial infarction.
I'm not getting volume here.
connection, because you guys I'm wondering if there is a
It's part of it. can't hear this at all, right?
through my microphone. Well, what I can do is do it
I apologize for the delay.
Atherosclerosis is a
heart disease. contributing cause of coronary
lesions, which grow within the It is characterized by fatty
class which includes the walls if the incised arteries, a
These lesions, or plaques, form in a layer of the arterial wall
called the intima.
endothelium and a thin layer of active tissue, or collagen.
The high turbulence of blood at the bifurcations of the coronary
arteries begins the process of
endothelial layer. atherosclerosis by entering the
its permeability to monocytes, Injured endothelials increases
and change it to macrophages. whThese macrophages expressma
receptors for oxidized
LDLs. loInjured endothelium alsoor
increases its permeability to LDLs, which in the presence of
free radicals are oxidized and
The macrophages continue to babsorb oxidized LDLs.s.
And enlarged, become foam cells.
substances which cause the These macrophages also secrete
from the media and the migration of smooth muscle cells
and collagen in the intima. The presence of foam cells and
smooth muscle cells gives the appearance of a fatty streak.
The further proliferation of
collagen, and an increased smooth muscle cells and
formation of a fibrous plaque. absorption of lipid leads to
expands, necrosis occurs as the cells inside the lesion die from
lack of oxygen. This lipid-rich plaque, the
necrotic center, is called an atheromata.
Eventually, the necrotic region is walled off by calcification
of the plaque base, and a thickening of the fibrous cap,
giving rise to the complicated
A rupture of a lesion induces clotting, which begins with the
aggregation of platelets, followed by the accumulation of
fibrin, forming a thrombus. If this thrombus blocks the
blood flow, a coronary infarct
I apologize for the not-so-wonderful quality of the
images. We had to turn down the
resolution of the computer
weren't quite so nice. earlier on, and that's why they
idea of what we're trying to get But I think you got the general
Over time, because of a high-fat diet and too much
cholesterol in the blood, and normal physiological arrangement
of how the blood flows through
an abrasion to the blood vessel wall, which leads to invasion of
the cells called macrophages, which are beneficial cells
normally. But under this circumstance,
because they reside, and they start to take up LDL, what
happens is you have a build-up
which gradually gets larger, of a fatty deposit in the wall,
situation where it will rupture, ultimately leading to a
And that clot is what causes the causing a clot to form.
of the coronary vessel, cutting poff a small or a major portion
of the heart wall itself, which without direct, immediate
intervention, ultimately will lead just to scar tissue taking
the place of normal, healthy
And of course, that significantly reduces the
ability of the heart to contract
So what is the present and for and to function.
treatment for this problem? You've probably heard of bypass
surgery.
what is normally referred to as Mya massive heart attack.had
He was out playing tennis with
And fortunately one of his kids is an ER nurse.
So when he had this heart attack, she immediately got him
to the ER and they had to do a
Thanks to early intervention, he's doing extremely well.
And probably lost a lot less of his heart muscle than he would
have otherwise. So bypass surgery is common.
Stent placement is used to open up the occluded vessel and keep
it open.
that you put inside of the So it's sort of like a spring
Then, when it opens up, it vessel.
the vessel open, so that blood actually is a support to keep
Another possibility is can continue to flow.
But there are too few hearts and transplant.
so this has not really been a too mgood option in most them,
circumstances.
people who have heart disease go So often what happens, is
intervention. on One of the obvious ones isal
keeping your blood thin.
prescribe for people who are So doctors will actually
Aspirin thins your blood. This reduces the possibility of
clotting. A glass of red wine will help
thin your blood.
a nice red wine with dinner, So if you need an excuse to have
Of course, anti-hypertensives, here it is.
pressure down because the higher you want to keep your blood
risk you are for certain the blood pressure, the more at
Statins, everybody's favorite. problems.
regulate or control heart contraction and of course chest
pain. So that's what's going on now.
What's going on behind the
There are a number of clinical scenes?
therapies. trials for drugs and other
go to: clinicaltrials.gov If youThey list everythingshould
nationally and internationally. And basically, using that list,
which is quite lengthy, what I'm
idea of using your own stem cells for your own treatment.
So what's happening here is that
being taken out of your bone most frequently, stem cells are
So that's a relatively common procedure nowadays, where an MD
will simply go in with a needle into your hip and aspirate some
of your bone marrow, which is full of cells.
Not all of those cells are stem cells.
But the stem cells can be isolated, and then those stem
cells can be used to treat a
I'm listing this one about the variety of diseases.
chronic heart disease because this one is going on in Madison.
So just in our back yard, Dr. Lavalle is heading a study
in which the cells that will
blood vessels, that are called make the cells that line your
precursors, or progenitor cells ento those, out of the blood.he
He then uses those and injects
individuals that have a specific them into the heart of
And what the idea behind this clinical trial is that the blood
vessel cells will restore blood vessels to the ischemic heart.
Thereby increasing function and prolonging the life of the
patient, making the patient's life better.
So that's a particular type of
Yeah, go ahead. >> The vessel and wall, nothing
to do with the heart muscle?
muscle. But you cannot have heart muscle
without a very extensive blood
So each cardiac muscle cell is supply.
capillaries. associated with four different
dependent the heart muscle is upon its blood vessels.
So improving the blood supply to
function of the heart, not the heart will improve the
but overall by affecting the directly to the cardiac muscle,
oxygen to the heart. overall supply of nutrients and
study that you will find on this And the other major type of
marrow or mesenchymal stem particular Web site is for bone
So mesenchymal stem cells is a cells.
It doesn't refer to a very very general term.
It refers to a broad group of cell types that can be defined
by the proteins that they express on their surface.
And frequently, these mesenchymal stem cells come from
the bone marrow.
marrow and into the circulation. They will come out of the bone
discovered within the last few Another source that has been
cells is fat. yAnd you say, great, everybodyem
has fat.
into those areas. SThere are two types of fat.o
One is white fat, which is most of what we have.
Then there's brown fat, which we
baby. But as an adult, you still have
some, like underneath your
fat. shoulder blades, there's brown
within these areas of brown fat, So it's been discovered that
fat, you have stem cells. And these stem cells are your
own.
All they have to do is be isolated, and perhaps stimulated
in some fashion.
cardiac muscle, or more blood They could bvessels.o make more
And I noted that one planned
suggests that they will isolate stcardiac stem cells from thely
heart directly. And I will tell you about these
stem cells in just a minute.
dish and then inject them back Or to expand in a tissue culture
That's not yet started. So those are the clinicals.
I've shown you the traditional
using to treat heart disease. I have now talked to you about
ones that are in planning, are
trials. And now I'm going to talk to you
about things that will happen in
probably not for five or ten, or the future at some point, but
I think we've all heard about human embryonic stem cells.
They're quite controversial.
campus, thanks to the work of TheyJamie Thomson and his this
collaborators.
and culture human embryonic stem Jamie was the first to isolate
And the beauty of these cells is cells.
cell type you want, from that they can give rise to any
to heart, to skeletal muscle, neuanything you want, liver,ge,
kidney. These human embryonic stem cells
can make these cells. And they can make endothelial
progenitors, cardiac stem cells,
But there are some issues. neuro stem cells, etc.
about that. I'm nBut they're not easy.etail
And they probably will not, in
of clinical therapy. the near future, be for any sort
that. But they are a possible source,
because they are an unlimited source.
You can make as many of these cells as you want.
And that is the beauty of it. But more recently, Dr. Thomson
and several other labs, a lab in
labs in the US have reported the Japan, and a couple of other
induced pluripotent stem cells. isolWhat does this mean?led
It means that I could take a
into a tissue culture dish, and biothose cells would grow.t it
And then I would genetically
four different gene products, moand be able to isolate from or
those modified cells, things
like embryonic stem cells. that look almost exactly
They're nobody else's. Except they're yours.
these induced pluripotent stem So the potential here is that
specific, and because they don't cells, because they are patient
embryos, they're not require the destruction of any
They're not unethical. controversial.
so you don't have to worry about And they are patient specific,
Potentially, these may be the cells that will be used in cell
therapies of the future.
learn about these cells. But again, we have a lot to
isolated. And probably will not be used
for at least ten years down the road, unless something unusual
happens.
what's happening in the future, or could happen in the future,
so that we can focus our
most productive, particularly in energies in a way that would be
So, I've been talking a lot tabout stem cells..
What are stem cells?
day in the news, it seems. We hear stem cells almost every
Internet. On telWhat is a stem cell?on the
A stem cell is quite an amazing cell in that it can replicate
itself and make identical copies
appropriate stimulus, give rise to cells that will then go on
and differentiate to form neurons, to form blood, to form
muscle, etc.
pluripotent, because they have a So stem cells are called
that they can form. This is an incredible source of
cells and tissue that could be
So, just a few definitions to help clarify what we're talking
about.
That means they can make copies of themselves for years on end,
with no problem, without
They are pluripotent or multipotent, depending upon how
many different cell types they
So pluripotent cells from an can form.
form any cell type in your body at all, whereas multipotent stem
cells might be able to form,
blood cells, and cardiac muscle cells, but only those three
types.
pluripotent and multipotent. That's the difference between
step away from a stem cell, it Then once a cell has taken a
progenitor cell rather than a is generastem cell.t of as a
It has limited ability to self-renew.
It will only self-renew so many times before it no longer can.
And it's usually multipotent. That is, it can only make two,
three or maybe four different cell types.
Then we have yet another beast, which comes from stem cell to
progenitor. Then we have the transit
amplifying cell, which come from
And these have a very limited number of times they divide
before they actually
So if you think of your skin. You have stem cells on the very
bottom layer. Then when they divide, they have
to give rise to all of those
protect us from the outside layers of world.ells that
And you can think of those stem cells, at least at the bottom,
as being transit amplifying cells, which then lead to the
differentiated cells that we
outside of our body. recognized as the skin on the
unipotent cells. And differentiated cells are
are at least 200 different types What's kind of amazing is there
So what's a cardiac stem cell? of these cells in our bodies.
gentleman rediscovered for the Well, a number of years ago, a
the cells in the heart can world that the heart can divide,
which was a shock, because the divide, but to a limited extent,
years ago, said that once you were born, you couldn't get any
more cardiac muscle cells.
With normal wear and tear, the He said, no, that's wrong.
get worn out. But if you have heart disease or
have a heart attack, there
to replace what is lost. aren't enough stem cells there
occasional day-to-day cells that It's only there to replace the
functions. are lost in normal body
multipotent. So cardiac stem cells are
three different cell parts. YoMost important, the cardiacorm
muscle cell, but also endothelial cells, because you
need a blood supply.
have very important coronary And smooth muscle, because you
about in the cartoon not too arteries, as we just learned
to the cardiac muscle. long ago that supply the blood
considered multipotent, because So ait can make these threed be
different types.
cell is that it needs to be self-renewing for a lifetime
supply. So we have to have these cells
around for our entire lives so
myocytes as needed. In a scientist's definition, you
have to be able to take these stem cells out of the body and
put them in a tissue culture
maintaining them as stem cells. Because ultimately, you want to
expand the numbers so that you
cells. can do a cell therapy with these
And finally, they need the So they need to be expandable.
the region of the heart attack, abilthe ischemic area of apair
myocardial infarction.
life revolves around. And there are hundreds of other
labs around the world that are
together to try to figure out also how this will work.minds
So, where do these stem cells come from?
First, I'm going to tell you
live in the heart, which you say about the ones that actually
place for them to be. So, frequently we'll use rodents
in the lab as a model to look at
system, understand its things like the cardiovascular
and function. deSo the focus has been on then
mouse or the rat. And basically, what I'd like you
to take home here is not the
important. names, which are really not
developmental sequence. BThere are cells that live ina
and among the muscle cells in the ventricle and the atrium.
And they express certain
mark them as stem cells, that prosays it is a stem cell.that
That is the only thing at the moment that says this is a
cardiac stem cell.
proteins. And it does not make any nucleic
proteins that say this is a cardiac cell.
All it says is this is a stem cell.
Now, when this cell stops being a stem cell and divides, and
starts the process of differentiation, not only does
it maintain the stem cell antigens or proteins on the
surface, but it now starts to express the nucleic proteins
that say cardiac or smooth
Then the next step in the process is the expression of
cytoplasmic and membrane
express the stem cell markers as proteins, but they continue to
Then the final step kind of becomes a differentiated
definitive muscle cell. It loses the cell surface
markers that say stem cell. It only makes the cytoplasmic
and the nucleic protein.
It's a way to think about So thisthings.rocess.
You have cells in the heart that
waiting for some kind of a are sort of sitting there,
They will divide occasionally, signal.
But when they get a signal, they but not often.
progenitor cell, to a precursor cell, and ultimately to a
differentiated muscle cell. This is how the process works,
and how it has been characterized so far.
And all of this occurs in the mouse, but it also occurs in us.
It's just a lot harder to study in humans.
What do these cells look like?
see what it actually looks like. This is always cool when you can
cells, which are very large On the outsidcells. have muscle
They're stained red because they're stained with what's
called an antibody. And the antibody recognizes a
particular protein. Then it's labeled with a
fluorescent marker, which could be red, green, yellow or blue.
And what is unique about the
small. stem cells is they're very, very
a stem cell is a nucleus. So It has a very thin rim ofcall
cytoplasm around it.
They're mostly nucleus, and Tvery, very little cytoplasm..
This was stained for a couple of different proteins.
These are two nucleic proteins
specific. This is a stem cell cartoon.
Don't worry too much about the
But I guess what I'd like you to colors and where they are.
there are little pockets of take hothese stem cells. heart,
And they are sitting there, occasionally dividing, but
they're waiting for a signal, which says divide, amplify and
replace some cells over here
This is normal. This happens throughout your
life. ( inaudible )
In the individual stem cell,
it's gone? progresses and differentiates,
a limited supply? >> There can be a limited
supply. That's actually a very good
question. So there's a group of stem
cells.
Let's say there are 1,000 stem
to diminish. And over time, they will start
particularly when you're But they're very robust,
to increase in size. growing, because your heart has
adult, you're not going to grow But ththat much any more. be an
Then they would sort of plateau.
or older, they're going to be in And by the time you're say, 60
to be there in some numbers declbecause they divide andgoing
replicate themselves at the same
cells that will go on and make time that they divide and make
Very good question. mYeah?.
Stimulate that continuing debate.
You got it. Excellent.
Would you like to come and work in my lab?
( laughter )
more about-- Let me tell you a little bit
( inaudible ) ( laughter ) what?
Okay, so what is this place that the stem cells live
look like?
another vocabulary term, which Now I'm going to give you
different context. you've probably heard in a
Everybody in the stem cell world This is the stem cell niche.
context of a stem cell niche, which means sort of a home and
a supporting structure of extracellular matrix, and also
more importantly, other cells.
And basically, we're looking at an area here, which is now in an
expanded view.
muscle cells. ThThe cells right here in theac
middle that have what's called
extracellular matrix surrounding a basal lamina, which is an
But they don't want to live all them, thoby themselves.m cells.
They want to be surrounded by cells that they know and love.
So you have these other cells.
amplifying cells. So these cells that are larger
and kind of purplish in the middle are no longer stem cells.
They've taken a step away from
They walked out the door and the niche.
The stem cells that are here they can't go back.
of themselves, whereas these stay, and continue to make more
muscle cells, endothelial cells, guys will go on and make cardiac
So what do these cells need? or smooth muscle cells.
other. They need to be close to each
cells. There are proteins that connect
seems to be very important in maintaining stem cells as stem
cells.
like gap junctions, where the But ycells are directly inthings
cytoplasmic contact with each other.
And you have to have other
You have to have other cell types, maybe cardiac
fibroblasts.
this point. But what is emerging is kind of
a support structure, if you will, for the stem cells, which
we call the niche.
Can you can actually see them Whin the heart, rather thanke?
just in a drawing.
This is a paper from 2005, Yes, you can.
And basically, they were published in Nature.
protein called Violet 1. staining for a particular
see the dark brown nuclei, the And if you look in here and you
are the stem cells based upon da nucleic protein that they're
making. So we can actually see these
things. We're starting to understand
what they look like.
scientist is to recreate that stem cell niche outside the
heart in order to be able to
particular patient, expand them and then put them back into the
heart of that patient to see if that will benefit the patient by
regenerating cardiac muscle and blood vessels.
So all around the world, are
regenerative medicine. popping up study centers for
medicine, regeneration, figuring This is the new wave of
more, to regenerate their cells, out ways to get organs to make
functioning day-to-day life. that are part of their normal
take everything but the cardiac myocytes from a heart, from a
rodent, and you put that in a tissue culture dish.
Then you take out the stem
that they express on the cells, based upon the proteins
You put them into culture, and surface.
are ways of detecting if they you folremain stem cells. there
And of course, if they go off and differentiate into
something, you can see
cardiac muscle cells. And there are also ways of
detecting smooth muscle for the vascular and endothelial
cells, as well. What has been found, as we look
at these things, is that they won't just grow in any old
tissue culture dish.
conditions, in particular growth They need special media
cytokines, are important for factors, which we sometimes call
maintaining them as undifferentiated cells so that
they can be expanded. This is a diagramatic way of
thinking about it, which often
generate different pictures in helps, because words sometimes
So if you start with what we different people's minds.
or cardiac stem cell, it call a cardiac progenitor cell
on the surface and one on the expresses cenucleus.oteins, one
It will go on and some will stay
That's what this little diagram stemeans.s.
The arrow out to the side is the
But another stem cell will duplication of the stem cell.
we call mesoderm, which is what dividmakes all of muscle. what
And then, within that mesoderm, you have a differentiation into
a lineage that will make a
cell, and an endothelial cell. smooth muscle, cardiac muscle
This is the smooth muscle This is thlineage.c lineage.
This is the endothelial lineage.
thinking about stem cells, So this is a conceptual way of
amplifying cells, to progenitor cells, to transit
will. In the meantime, of course,
these cells can be used for drug
will ultimately benefit people studies and other things that
therapies. down the road for different
to a person which would expand Because if we could give a drug
a huge benefit. theIt would allow them to do be
things, like regenerate parts of
That's the ultimate goal. You want to do this in a
minimally invasive fashion. So if you need to put in cells,
that's one thing. But if you can simply give a
drug that will stimulate the
that's even better. ceAnd if you can do somethingt,
that's not a drug and have side effects, that would be even
better. That's the sort of way we're
thinking about it.
precisely what a stem cell looks Now, because we don't know
don't know all the defining like, a cafeatures.m cell, we
We can't isolate a cell and say yes, this is a cardiac stem
cell, without killing it. Because to define it, you have
to get inside to the proteins that define the cell, as far as
we know it. So you don't want to do that,
because you want to keep the
What other labs have done is to use a transgenic approach in
rodents to define these cells.
They exist based on a definition And yes, they do exist.
express. of what genes and proteins they
these cells can form all three And the bottom line here is that
endothelial cell, and the smooth types, the cardiac myocyte, the
Two different labs have found this using completely different
approaches. Another lab found that you could
get at least smooth muscle and
The way that development works cardiac myocytes.
of the capability of the cell from the pluripotent cell to the
adult cell. So here, they have found a cell
that is multipotent and can make
Both of these two labs did it thindependently..
This lab said it could make at
So those are the adult sources. To summarize, the cells that
live in the heart is what we
And now what I'm going to talk have just discussed.
mesenchymal stem cells, which acome from bone marrowd
predominantly.
sources in the body, such as But they can come from other
What's in bone marrow? fat.
Most of us think of it as a Alsource of new blood cells..
Perhaps where red blood cell
white blood cell precursors. precursors come from, as well as
vessels. And cells that will make blood
that have been defined by a Andgroup in Minnesota, calledngs
multipotent adult progenitor
It sounds very impressive. cells.
they're not that impressive, at Theyleast in my book., so
But they do make lots of other
And then we have this sort of vaguely defined mesenchymal stem
cell population.
types which have not yet been discovered which like to live in
the bone marrow, as well. So don't worry about these
names.
this particular group did a But what wastudy.resting was
And what they got to occur, was that they mobilized the cells
that normally are happy and comfy in the bone marrow to get
out of the bone marrow, come up to the heart because the heart
has problems. They damaged the heart and then
they used certain cytokines or
come out of the bone marrow, growth factors and got cells to
contribute to the cells within hone in on the heart, and
Isn't that amazing? ( inaudible )t.
Yes, just on rodents. But you know people are thinking
about how to do this in people. We just don't know exactly what
signal to send. So a question that I posed was
you have these cells which
surface in the bone marrow and expressed the same thing on the
difference between them, or are in the hethey the same.at's the
Is there really an endogenous population, or does it all come
from the bone marrow? Or does it only get supplemented
by the bone marrow? It's an interesting question.
And there are other cells that
have not yet identified in any exist in the bone marrow that we
contribute to cells in the way, which nonetheless can
So what is it that stimulates these cells to take part in
cardiac regeneration? There are these growth factors,
cytokines, called stem cell factor, or granulocyte colony
stimulating factor, G-CSF for short.
And again, if you give a mouse
infarction, usually the way that's done is by tying off one
of their coronary arteries, which basically mimics what
happens in a human heart attack patient, and then give them one
or both of these growth factors,
And the way that the group they found that rats did better.
things coming out of the bone marrow that are playing ae
beneficial effect directly with cells of the heart.
Mesenchymal cells are usually bone marrow derived.
They circulate in our blood.
umbilical cord blood. There are a number of people who
are starting to save umbilical
the idea that down the road, cord blood from their kids, with
some stem cells, and this is maybe the kid's going to need
here in their own blood. their only stem cells, right
These cells, once you take them out of the body, are very happy
to grow and expand in numbers.
what we call the micro But they require something in
them to do what we want, because environment that will stimulate
apparently. theThey can make bone.ings
They can make fat.
But if you want it to make They can make cartilage.
certain combination of things, heart, you have to give them a
we call paracrine factors, which either cell-cell contact or what
factors for which there are receptors on these particular
cells.
mesenchymal stem cells is that The wonderful thing about
They prevent an immune response. they suppress the immune system.
certain clinical situations, for So what has been happening in
kidney transplant, at the same people who have, for example, a
of mesenchymal stem cells from time they will get an injection
And the presence of those stem the bone.
transplant actually suppresses cells at the same time as the
tolerance of the transplanted the immune sorgan.and leads to
This is how it does it. I'm not going to go into this in
detail. But generally there are several
mechanisms by which mesenchymal stem cells can suppress the
immune response, and thereby
organ transplant, which is facilitate either a cellular or
Brown fat, or adipose tissue. So the stem cells are thought to
be much higher in concentration in brown fat than in white fat,
but they do exist in white fat. Brown fat is much less in us
than when we were kids, but we
They're multipotent. still have some.
vascular smooth muscle and They can form cardiac myocytes,
what we need. eAnd if you were to look at a
mouse model, which is the results are shown here, they
were basically looking for three
from the adipose stem cell. diBasically, this lab isolatede
adipose stem cells based on a surface marker and injected them
into a rat. And I don't recall if it was
directly into the heart, or if
circulation. it was just into the peripheral
these cells were able to graft But what they found was that
needed to be done, such as and do all of the things that
myocytes. And all of these are antibody
stained.
But this is the sort of evidence I won't go into it in detail.
okay, this is a stem cell. that is presented when you say,
there you are, you've got cardiac muscle, and all of the
different cell types that you need.
So we know it works.
really need the cells at all, which alludes to something that
I mentioned earlier.
the years has been that no An interesting observation over
you put into an infarcted heart, matter what type of cell type
It reduces the amount of it helps.
the function of the heart. scarring and overall it helps
You would think you'd want to put in something that you would
normally find in a heart. You don't have to.
You can put in skeletal muscle
You can put in bone marrow cells.
There are a number of other cell cells.
And all of these have led to types that have been tried.
can't be the cells by themselves some benefit, which says it
different cell types. Now we're asking what it is
that the cells secrete when they're implanted that makes the
difference. Because you don't actually get
many cardiac muscle cells actually forming, but you do get
a much greater benefit to the functioning of the heart than
you would expect, based upon the
differentiate. number of cells that
cells, they also seem to prevent And not only do they replace the
They're secreting something which says to the cardiac
myocytes that are in there, you don't have to die.
This is what we call a paracrine
This is just a little diagram. signal.
endocrine, which is at the top Many of us have heard of
gland is making thyroid hormone, here, which is say, your thyroid
distance in the blood and acts which then goes down quite a
Paracrine signaling is at the on upper right here.ce.
Basically, a cell makes a growth
one or two cell distances away factor or cytokine and then just
that has a receptor. from that, there's another cell
paracrine signaling. This is what we mean by
that makes a difference when It's short distance signaling
the heart. you're transplanting cells into
cardiac progenitor cells. I told you about the bone marrow
mesenchymal stem cells, also
Let's now talk about embryonic some brown fat stem cells.
ones. steEmbryonic stem cells areal
derived from embryos. They are the part of the embryo
that will give rise to
organism itself, not the everything in the body of the
placenta, not the amnion, not the yolk sac, none of that, just
the cells in the embryo proper. And it's been found that these
can be cultured outside the animal, with no loss of
pluripotency for years. No other cell types do this,
except cancer, and that's a completely different mechanism.
Cancer is not normal. These are normal cells.
They can differentiate in the tissue culture dish to form
cardiac progenitor cells, and cardiac myocytes.
And myocytes that are in these
in clusters of cells. ceSo it's not like you get anre
entire patch of muscle cells all
They're intermixed, which actually makes them a little bit
difficult to manipulate, because
cells away from the rest. This is a way of thinking about
it. You start with, say, a human
embryonic stem cell, which is pluripotent.
It expresses certain proteins that say it's an embryonic stem
cell. It goes on and makes more of
itself, but also sometimes, it
differentiate. divides and starts to
endoderm, mesoderm or ectoderm. It The muscle comes from thether
mesoderm. So it differentiates to form a
mesodermal stem cell, which expresses a certain nucleic
protein.
becomes more limited to blood Then it goeand heart.urther and
Then it expresses something else.
And some of these will go on to form exclusively blood, or blood
and endothelial cells.
smooth muscle cells. Another branch will go and form
form cardiac progenitor cells and ultimately cardiac myocytesd
over the course of about a week to ten days in tissue culture.
So that is one view.
slightly more colorful. You start with an embryonic stem
cell and then you gradually progress through the
accumulation of different membrane proteins, cytoplasmic
proteins, and nucleic proteins. I don't want you to worry about
the names, just the overall process.
Some of these will then become
And then ultimately, our hope is mesodermal cells.
combination of membrane protein markers on these cells so that
we can say, this is a cardiac muscle stem cell.
We haven't found that yet.
the cardiac muscle cell. Ultimately, that will form
direction. It might come from more than one
fashion. It may not come in a linear
the way that these cells It may have some flexibility in
This is not a great picture. develop.
staining of different cell It's something in a fluorescence
It shows you that indeed you can proteins within cardiac muscle.
cells. get cardiac muscle from the
various groups have shown is And one of the things that
stem cells and you inject them that you take different types of
infarction or heart attack, that into a mouse model of myocardial
form the cell types that are you can get these stem cells to
So, whether it's needed to regenerate the heart.
mesodermal stem cells, or even undifferentiated stem cells, or
differentiated, all of these can cardiac myocytes that have
myocardial infarction and they be injected into an area of
functional parts of the heart. will sit there and become
own, have shown that in a rodent A number of labs, including our
And it can work. model, this is the way it works.
should work equally well in Therefore,people.nciple, it
I'm not going to go into this.
to show that they have stayed where we injected them, and that
they have differentiated. This is the end result.
The most important thing is function.
It's nice if you have different cell types in the heart.
The most important thing is improved function.
And what we're doing here is
the heart after contraction. we're looking at the diameter of
injection of cells improves, And we're showing that
diameter, so that the blood flows out of the heart more
efficiently.
the shortening of the muscle. ThAgain, after heart attack,f
injection of cells increases the
It puts them back into a normal range of function, which is
shown here at the left, gradually getting improvement of
the physiological parameters of the heart.
That is the bottom line.
And what we showed was that Thmouse ES cells in the mouset.
heart can survive, differentiate
cells that we needed. More importantly, it blunted
remodeling, prevented scar
And we showed in a separate paper that it increased survival
of the cells that were already
We were able to do this with a there.
cells. relatively small number of
invasive therapy that's introducing cells, you want to
minimize the cells that you have
don't want other funny things to inject,going on.ecause you
The less cells, the less likely there is to be a problem.
You have to have enough cells to
The problem with ES cells is get a response that is desired.
We don't yet have a way of tumor formation.
the cells that we want. proIf they are used, becausecing
they're not from the individual,
immunosuppression. we will need to have
think about this is to increase Athe number of ES cells that we
have, that will match all of the
that represent an immune system and a response to anything that
is introduced into the body.
in people. These are called the HLA markers
tolerance. We need to think about
system accept these cells, and That is, making the immune
So you can see the use of human embryonic stem cells, as we have
them now, faces a lot of
ones, before anything happens with them in a clinical setting.
Yeah? ( inaudible )
Are the tumors cancerous? No.
( inaudible ) That's something different.
In this particular explanation, embryonic stem cells, because
they are pluripotent, make lots of different cell types, a lot
of different cell types.
lining of the gut, and They make neurons, and bone, and
And sometimes, these cells will make little tumors.
They're not what we think of as tumors.
They're benign structures that
types. have lots of differentiated cell
them is that they will interfere The only threat that is posed by
You don't want to have a blob of with the function of the heart.
your heart, which is potentially cells growing on the outside of
But yes, if I can get back to your question about stimulating
cells into a cancer, that's a completely different subject.
( inaudible ) Perhaps, as you wish.
Since we can't use ES cells,
induced pluripotent stem cell. a new player on the scene is the
isolated in a number of labs. There was the big broo-ha-ha,
even on the regular news saying,
And what are these cells? These are just cells that are
growing in your skin, what we call the dermis part, underneath
the epidermis.
transform them into pluripotent stem cells by introducing ad
couple of different gene
The Thomson lab used several products.
Other labs have also used nucleic proteins, but different
ones. So there's some combination
which will work, and it's not just one combination, it could
be several different things.
reprogramming these cells, which The problem is that when you're
you're changing their phenotypes is what you're really doing,
fibroblast. They're not a skin cell anymore,
they're a stem cell now.
abilities to make cardiac, And that stem cell has the same
neuron, glial, fat, bone, etc. smooth muscle, skeletal muscle,
manipulated. But they have been genetically
else? Could thYes, possibly.mething
That's a major concern. So we'd like to be able to do
this, but we'd like to be able
People haven't yet discovered how to do that in a way that
does not require genetic
It's something that's a very manipulation of the cells.
But what could it do for us? intensive subject of research.
start to analyze skin samples from people who have diseases.
And it will allow us to have a
recreate, in a tissue culture podish, what goes on in thell
diseased individual, and thereby
knowledge to the process of disease and its development in
some patients that we don't know
disease works. very much at all about how the
cells are patient specific, they Down the road, because these
response. You can take these cells and put
them right back into the patient
And they won't suffer any adverse effects due to the
immune response, which is really
But again, this work is down the exciting.
Let me finish up, because I'm probably running over.
I like to talk. So you can get cardiac stem
cells from several different
There are some that live in the sheart..
There are some that live
and in other places such as apparenadipose tissue. marrow
And outside sources, or different sources, are embryonic
stem cells and induced
of the future. pluripotent stem cells, the wave
to differentiate into three All of different types.be able
And we have found that they have
we're still learning about. And as I've said several times
during the course of my talk, a definitive marker for cardiac
stem cells has not yet been discovered.
They express stem cell proteins,
combination that says it's a but we haven't yet found the
stem cell, for example. caThat's the end of my talk.er
I'll be happy to answer any questions that I can.
Remember, I'm not an MD.
( inaudible ) >> The study that's going on
here. >> Oh, yes, the clinical study
on the endothelial progenitors. >> You get the stimulation of
blood vessels?
doctors take blood from the patient, and isolate from the
blood, certain cells that have
These are called endothelial certain surface markers.
When they differentiate, they go progenitor cells.
line our blood vessels. They can make new blood vessels.
If there's already an area of infarct and compromised muscle,
aren't those cardiac cells
Yes. already dead?
blood flow to a dead area help >> So then how does increasing
A good question. anything?
can't give you a detailed answer What I would propose to you, I
But what I would propose to you is if you can induce an area
that has poor blood supply to form new blood vessels, that
will permit the opportunity for other stem cells to get in and
repopulate the area.
looking at it. That's a simplistic way of
is. B>> The second question was inal
relation to the issue of
potential for things going off differentiation and the
stem cells. inDoes the area of epigeneticse
intersect with these issues?
question. Under normal circumstances, as
stem cells differentiate, if
supposed to do, such as form a they do something they're not
that particular location, there care cellular mechanisms thatr
will lead to what is called cell
The body has its own internal mechanisms which prevent cells
from doing inappropriate things.
not all of the chromosomes go Sointo each cell, for example.,
And those sorts of cells, because of what we call cell
checkpoints, would end up dying and being re-absorbed by the
surrounding tissue. That's the normal situation.
Now, you go outside, you
the stuff that's coming out of breathe in diesel exhaust and
that has mercury introduced into factories, and you drink water
and it's all rained down into our ponds, and you have the loss
of certain chemicals into our environment, that's where you
have problems.
things happening. And I can't say much about this,
because I am in no way an expert.
There are experts on campus.
talking about stem cells in Ancancer, I think you shouldle
invite people along that line.
people on campus who are very much interested in cancer stem
cells, which I could easily try to talk about for a much longer
time, but I'd be wasting your time because I'm not an expert.
But yes, these things can happen.
But normally, they should not happen.
And it's only when something
reason, gets in and influences outside the body, for whatever
that we start to have problems. I hope that at least a little,
bit addresses your question.
My niece's father-in-law went to Thailand and was supposed to
have stem cells, somehow, put into his heart because he had
heart problems. My question is, is there real
research being done on human
He did die. >> Unfortunately, most of us
will go on to not survive.
I'm sorry for the humor. That's a normal part of life.
gave you before about the If clinical trials, those aret I
international trials. As far as I know, no one is
introducing cardiac stem cells
In other countries, bone marrow istem cells are being injected.
into the heart. So it's possible that in
Thailand there was a legitimate study, a clinical trial, that
only could occur because it's not governed by US policies.
We have very restrictive
best for us, though some people powould argue that they'rely
restrictive.
opinion in that regard, because I'I'm not qualified to.an
But yes, there are studies, ongoing, in the world in
different locations, where stem cells are being introduced into
the heart.
There will always be someone to But yotake advantage. point.
So it behooves you before going to a place like that to get some
information that legitimizes
Because sometimes emotions run that particular circumstance.
faster than logic.