ESL Video Quiz: TOEFL Quiz 20: Creating Human Tissues

Quiz by: Danielle_BIA
Quiz #: 14536
(ESL Category: listening) Listening comprehension
Listening comprehension 7776

I'd like to show you a video of some of the models I work with.
They're all the perfect size, and they don't have an ounce of fat. Did
I mention they're gorgeous? And they're scientific models? (Laughs)

As you might have guessed, I'm a tissue engineer, and this is a
video of some of the beating heart that I've engineered in the lab.
And one day we hope that these tissues can serve as replacement
parts for the human body. But what I'm going to tell you about
today is how these tissues make awesome models.

Well, let's think about the drug screening process for a moment.
You go from drug formulation, lab testing, animal testing, and then
clinical trials, which you might call human testing, before the drugs
get to market. It costs a lot of money, a lot of time, and sometimes,
even when a drug hits the market, it acts in an unpredictable way
and actually hurts people. And the later it fails, the worse the

It all boils down to two issues. One, humans are not rats, and two,
despite our incredible similarities to one another, actually those tiny
differences between you and I have huge impacts with how we
metabolize drugs and how those drugs affect us.

So what if we had better models in the lab that could not only mimic
us better than rats but also reflect our diversity? Let's see how we
can do it with tissue engineering.

One of the key technologies that's really important is what's called
induced pluripotent stem cells. They were developed in Japan pretty
recently. Okay, induced pluripotent stem cells. They're a lot like
embryonic stem cells except without the controversy. We induce
cells, okay, say, skin cells, by adding a few genes to them, culturing
them, and then harvesting them. So they're skin cells that can be
tricked, kind of like cellular amnesia, into an embryonic state. So
without the controversy, that's cool thing number one. Cool thing
number two, you can grow any type of tissue out of them: brain,
heart, liver, you get the picture, but out of your cells. So we can
make a model of your heart, your brain on a chip.

Generating tissues of predictable density and behavior is the second
piece, and will be really key towards getting these models to be
adopted for drug discovery. And this is a schematic of a bioreactor
we're developing in our lab to help engineer tissues in a more
modular, scalable way. Going forward, imagine a massively parallel
version of this with thousands of pieces of human tissue. It would
be like having a clinical trial on a chip.

But another thing about these induced pluripotent stem cells is that
if we take some skin cells, let's say, from people with a genetic
disease and we engineer tissues out of them, we can actually use
tissue-engineering techniques to generate models of those diseases
in the lab. Here's an example from Kevin Eggan's lab at Harvard. He
generated neurons from these induced pluripotent stem cells from
patients who have Lou Gehrig's Disease, and he differentiated them
into neurons, and what's amazing is that these neurons also show
symptoms of the disease. So with disease models like these, we can
fight back faster than ever before and understand the disease better
than ever before, and maybe discover drugs even faster. This is
another example of patient-specific stem cells that were engineered
from someone with retinitis pigmentosa. This is a degeneration of
the retina. It's a disease that runs in my family, and we really hope
that cells like these will help us find a cure.

So some people think that these models sound well and good, but
ask, "Well, are these really as good as the rat?" The rat is an entire
organism, after all, with interacting networks of organs. A drug for
the heart can get metabolized in the liver, and some of the
byproducts may be stored in the fat. Don't you miss all that with
these tissue-engineered models? Well, this is another trend in the
field. By combining tissue engineering techniques with
microfluidics, the field is actually evolving towards just that, a
model of the entire ecosystem of the body, complete with multiple
organ systems to be able to test how a drug you might take for your
blood pressure might affect your liver or an antidepressant might
affect your heart. These systems are really hard to build, but we're
just starting to be able to get there, and so, watch out.

But that's not even all of it, because once a drug is approved, tissue
engineering techniques can actually help us develop more
personalized treatments. This is an example that you might care
about someday, and I hope you never do, because imagine if you
ever get that call that gives you that bad news that you might have
cancer. Wouldn't you rather test to see if those cancer drugs you're
going to take are going to work on your cancer? This is an example
from Karen Burg's lab, where they're using inkjet technologies to
print breast cancer cells and study its progressions and treatments.
And some of our colleagues at Tufts are mixing models like these
with tissue-engineered bone to see how cancer might spread from
one part of the body to the next, and you can imagine those kinds
of multi-tissue chips to be the next generation of these kinds of

And so thinking about the models that we've just discussed, you
can see, going forward, that tissue engineering is actually poised to
help revolutionize drug screening at every single step of the path:
disease models making for better drug formulations, massively
parallel human tissue models helping to revolutionize lab testing,
reduce animal testing and human testing in clinical trials, and
individualized therapies that disrupt what we even consider to be a
market at all. Essentially, we're dramatically speeding up that
feedback between developing a molecule and learning about how it
acts in the human body. Our process for doing this is essentially
transforming biotechnology and pharmacology into an information
technology, helping us discover and evaluate drugs faster, more
cheaply and more effectively. It gives new meaning to models
against animal testing, doesn't it? Thank you. (Applause)

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