After Heart Attack, Turning Scar Tissue Into Heart Cells

After Heart Attack, Turning Scar Tissue Into Heart Cells

After Heart Attack, Turning Scar Tissue Into Heart Cells

A study published Wednesday in the journal Nature revealed that scientists have managed to convert damaged tissue into functioning heart muscle by inducing mild heart attacks on lab mice then coaxing their hearts into rebuilding themselves. In collaboration with KQED’s QUEST program, correspondent Spencer Michels reports.


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0.29 -> bjbjLULU GWEN IFILL: Next, a development that could be good news for millions of heart attack
3.75 -> victims.
5.1 -> Scientists announced they have managed to convert damaged tissue into functioning heart
8.84 -> muscle.
9.84 -> The research appeared today in the science journal Nature.
12.79 -> NewsHour correspondent Spencer Michels has our story, produced in collaboration with
16.64 -> KQED San Francisco's QUEST program.
19.93 -> And a note: Some of the pictures of the medical procedures are graphic.
24.1 -> SPENCER MICHELS: In hospitals all over the country, doctors try to keep alive the more
30.39 -> than five million Americans with damaged hearts, a result of heart attacks.
35.43 -> Damage means their hearts can no longer beat at full capacity.
40.25 -> When the heart muscle cells are deprived of oxygen during an attack, scar tissue forms
45.68 -> in the heart, tissue that doesn't beat like other heart cells do.
49.99 -> Now, in what they consider a dramatic development, scientists at the Gladstone Institutes in
55.6 -> San Francisco have figured out a way to transform scar-forming cardiac cells into beating heart
62.36 -> muscle in mice, and hope they can replicate the feat in humans.
68.33 -> Deepak Srivastava directs cardiovascular and stem cell research at Gladstone, an independent
73.99 -> biomedical research institution.
76.79 -> He led the team that published results in Nature and explained the challenge and what
81.58 -> he called the breakthrough.
82.59 -> DR.
83.59 -> DEEPAK SRIVASTAVA, Gladstone Institutes: From the moment an embryo is three weeks old until
87.64 -> the day an organism dies, the heart never takes a break.
92.37 -> The heart cell is unique in that it incorporates some features of brain cells, and some features
97.53 -> of muscle cells all together.
100.47 -> It's actually an amazing thing to see cells in a dish that just without any stimulus just
105.47 -> start contracting.
107.28 -> And it's that property that allows the cells in unison to generate force and pump blood
112.61 -> through the body.
113.61 -> SPENCER MICHELS: Though doctors can save most patients' lives after a heart attack, they
118.27 -> can't always preserve all of their heart function.
120.83 -> DR.
121.83 -> DEEPAK SRIVASTAVA: An individual may have trouble walking up a flight of stairs.
125.02 -> They may have to stop several times trying to walk across the street to get to work.
129.86 -> There are a variety of approaches we use right now to help people who are left with damaged
133.4 -> hearts.
134.4 -> But none of them actually get to the root of the problem, which is replacing that damaged
140.249 -> heart muscle.
141.329 -> And that's where our focus has been at Gladstone.
143.249 -> And you have enough for how many mice today?
145.43 -> WOMAN: So I have enough for like three mice.
148.01 -> SPENCER MICHELS: Researchers here have discovered a way to coax mouse hearts into rebuilding
152.879 -> themselves.
154.059 -> In their experiments, they first give lab mice a mild heart attack.
157.65 -> DR.
158.65 -> DEEPAK SRIVASTAVA: We do a more limited type of heart attack that doesn't result in too
162.779 -> many symptoms in the mice and doesn't cause death.
165.76 -> So we first anesthetize the mice, so they don't feel any of the pain.
169.65 -> It's almost out.
171.659 -> There are billions of muscle cells in the heart that are important for the squeeze of
175.969 -> the heart.
177.099 -> But there's an equal number of cells that are really there to support the muscle cells,
181.809 -> and sort of form the architecture of the organ.
185.099 -> The support cells are the ones that actually make the scar after a heart attack, and the
190.23 -> breakthrough we have made is that we have found a way to genetically engineer these
195.06 -> cells to make new muscle, instead of scar.
198.529 -> SPENCER MICHELS: First, the researcher mimics a heart attack by cutting off blood to parts
203.14 -> of the heart.
204.14 -> Then, she injects three genes that will transform the scar cells into beating heart muscle cells.
210.569 -> DR.
211.569 -> DEEPAK SRIVASTAVA: Three months after the injury, what we find is quite remarkable.
216.299 -> Using ultrasounds on these animals, what we see is that the heart's function is greatly
222.059 -> restored.
223.579 -> The ultrasound provides us an image of the walls of the heart and the valves in the heart,
228.92 -> and shows how it squeezes and relaxes with each heartbeat.
233.56 -> It's very close to normal in the amount of blood it's able to pump out to the rest of
239.4 -> the body.
240.439 -> There's still some scar.
241.909 -> We can see that, but embedded within the scar tissue is new muscle.
246.15 -> SPENCER MICHELS: This new research has impressed Yerem Yeghiazarians, director of the Translational
251.629 -> Cardiac Stem Cell Program at the University of California, San Francisco, though he had
257.47 -> some questions.
258.47 -> DR.
259.47 -> YEREM YEGHIAZARIANS, University of California, San Francisco: So what we need to know is
261.59 -> if we can do the same thing using non-retroviral techniques with small molecules, if we can
267.95 -> replicate the experiments in larger animal models and eventually do this safely in humans,
273.01 -> because if we can do that, that could potentially revolutionize the way we treat our patients
278.17 -> with weakened hearts either after a heart attack or other causes for cardiac failure.
283.86 -> It is the first time that anybody has described this as a novel way of treating damaged hearts,
290.31 -> because up to this point, there are no medications and no devices that replace a scar in the
295.9 -> heart with beating functional heart muscle cells.
298.55 -> SPENCER MICHELS: Srivastava admits there is a long road ahead before the procedure can
303.94 -> save human lives.
305.2 -> DR.
306.2 -> DEEPAK SRIVASTAVA: We have to make sure that it's scalable to the size of a human heart
310.68 -> where, where instead of thousands of cells that we might need to regenerate in the mouse,
315.3 -> we may need millions in the human heart.
318.75 -> The second thing that we have to do is to make sure that this will be a safe approach.
322.81 -> And for that, we will likely use a larger animal model that's closer to human, such
328.03 -> as a pig.
329.46 -> And then the final thing that we really have to work out is, what is the best way to deliver
334.74 -> the reprogramming genes into the cells of the heart.
338.32 -> SPENCER MICHELS: Srivastava estimates it will be six or seven years before treatments might
342.84 -> be available for humans.
344.42 -> GWEN IFILL: On our website, we have more reporting on the science behind the genetic technique
349.43 -> researchers are using to repair hearts.
351.87 -> That's in a blog post from our colleagues at KQED QUEST on the NewsHour home page.
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358.211 -> City GWEN IFILL: Next, a development that could be good news for millions of heart attack
359.211 -> victims Normal Microsoft Office Word GWEN IFILL: Next, a development that could be good
360.211 -> news for millions of heart attack victims Title Microsoft Office Word Document MSWordDoc
361.211 -> Word.Document.8

Source: https://www.youtube.com/watch?v=ykapXgIR9nA