HOW STEM CELLS WORK
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How do stem cells work?
All of us have marveled at one point or another at how
a baby can be created simply from various cells. And looking at any fetal growth
chart will quickly tell you that two cells turns into dozens of cells that turn
into hundreds and thousands of cells, until you can see a baby beginning to
form. But just how does the human body do this? And how do those cells that make
up the fetal form know that they are going to turn into a heart, an arm, or
hair? It’s no wonder that creating another living being is so fascinating to us!
The secret behind all of human life are stem cells.
These cells are packed into tiny embryos, which are what fetuses are called
before they form fully enough to take on a visible form. Embryos are tiny, tiny
masses of cells. They are so small in fact that they can fit onto the head of a
pin. The cells that embryos are made up are called stem cells. Stem cells are
known as being pluripotent, which means that they can develop into any cell, any
muscle, any tissue, or any organ within the human body. While this allows for
embryos to develop everything they need to in order for the human body to
survive outside of the womb, stem cells also have another incredible power.
Because they are pluripotent, they can also be used to treat different diseases
and medical conditions.
Today stem cells are used to treat things such as
adult diabetes, kidney cancer, and liver diseases. But doctors, researchers, and
scientists are investigating ways to use stem cells even further and make their
medical advancements even more fantastic! Imagine being able to restore memory
cells to a person living with Alzheimer’s, or replacing skin that was lost in a
terrible fire. These are just two of the things that stem cells have the
capability to do. But first, researchers must first learn how to extract stem
cells and properly use them, manipulate them, and capture their power.
What is a Stem Cell?
There are 220
different types of cells within the human body. Regular cells only have the
ability to replicate and duplicate themselves. This means that tissue cells can
only create tissue and organ cells can only create other cells for that
particular organ. Stem cells on the other hand, are like a blank slate. They can
be used to create any cell in the body. And because they also have the ability
to self-renew, they can replicate themselves over and over again.
There are two different types of stem cells. The
first type is embryonic stem cells and the other type is adult stem cells.
Embryonic stem cells are what form a fetus in the earliest stages of life. These
stem cells will grow into a fetus, which will grow into a baby and a person when
they are implanted into a woman’s uterus. The embryo only has to be three to
five days old before it becomes full of stem cells that will eventually make up
the fetuses heart, eyes, brain, skin, and other parts of the body.
Adults also have stem cells within them. These lie
within certain vital organs such as the heart, brain, bone marrow, lungs, and
other organs. Adults have these stem cells so that their bodies can repair their
organs when they become damaged. Whether it’s from an accident, an illness, or
just everyday wear and tear on the organs, they begin to break down and become
damaged. Adult stem cells can step in and reproduce the damaged cells, so that
the organ works as effectively as it should. It was once believed that embryonic
stem cells were more powerful than adult stem cells. This was because it was
once thought that while embryonic stem cells can be reproduced to create any
other cell in the human body, adult stem cells could only reproduce the same
type of tissue from which they came. But, with more research being done all the
time, this is being proven as untrue. For instance, it’s been proven that adult
liver stem cells can also produce insulin, a job usually reserved for the
pancreas. This capability known as plasticity or transdifferentiation, might
only be one thing that adult stem cells have the powers to do.
How Stem Cells are Acquired and Worked in a Lab
Using stem cells for research first began in the
1980s when scientists started pulling these cells from mice and discovered ways
to grow them in laboratories. Then in 1998 scientists also found ways to
reproduce human embryonic cells. These human stem cells can be acquired through
two different ways. Either reproduction of the human body using a sperm and an
egg can be used, or through therapeutic cloning. To reproduce stem cells using a
sperm and an egg, researchers and scientists have embryos donated to them from
fertility clinics. This happens when a couple is trying to become pregnant and
so they create the embryos outside of the body. Sometimes, too many embryos are
created and the couple cannot have them all implanted. The extra embryos that
are not implanted are then donated to science so that these researchers can
continue to study the stem cells they contain.
Therapeutic cloning is a very complicated process
that to fully understand would take an article of its own. But here we’ll break
it down as simply as possible. Cloning uses a cell from the patient that needs
the treatment and merges it with an egg given by a donor. The nucleus is then
taken out of the egg and replaced with the cell taken from the patient. The egg
is then activated through either electricity or with chemicals and it then
divides. This creates a new embryo that contains the patient’s genetic matter.
This reduces the chance that the patient’s body will reject the new embryo once
Once an embryo has grown for three to five days,
it’s then called a blastocyst. Blastocysts are made up of about 100 cells. The
stem cells are those that are found in the innermost part of the blastocyst. And
it is from here that researchers will remove the stem cells and place them into
a Petri dish to grow in a solution that’s rich with nutrients. The stem cells
will then begin to grow and multiply and eventually, become far too large to
continue to sit in the Petri dish. Then at this time, the cells will be divided
up into multiple Petri dishes so that they can continue to be cultivated. This
will continue on for several months until the stem cells make up a stem cell
line. A stem cell line is a group of stem cells that have been grown and
cultivated, without differentiating in any way. Cell lines are often frozen and
shared amongst different laboratories.
While this may all sound quite basic, acquiring and
controlling stem cells within a laboratory environment is very difficult.
Researchers are always trying to find new and better ways to control stem cells,
and manipulate them to do what they want them to do. Adult stem cells are
especially difficult to work with in the laboratory. This is because stem cells
are more difficult to find in adults and also because adult stem cells don’t
replicate as well within the lab.
The Rewards and Challenges of Stem Cells
What scientists are working mostly on now is using
stem cells to treat disease. They’d like to be able to do this by simply
injecting new stem cells into a patient’s body where it would replace any
damaged cells. While this is the ideal situation, it’s still not possible
because scientists haven’t yet been able to direct a cell to differentiate into
a particular cell or tissue. This means that scientists haven’t yet found a way
to get a stem cell to develop into a liver or a brain cell once it’s inside the
human body. And even if they do find a way to differentiate the cells,
scientists still don’t know how they would control them once inside the patient.
Another problem found when working with stem cells is that there’s no way to
make sure that the patient’s body won’t reject the cell once it’s injected into
their body. This sometimes happens when the person’s immune system senses that
the stem cell is a foreign body within the human body. Because of its natural
abilities, the immune system will then label the cell as a danger and will
In nature, stem cells are given external and
internal cues that tell the stem cells what to do and how to function within the
body. The internal cues come from the genes found inside the stem cells. The
external cues are chemicals given by the body and surrounding cells that tell it
how to act. Being able to turn the genes on and off within a stem cell is
crucial to getting stem cells to differentiate. Scientists know this and so they
try to replicate that process by injecting certain genes into Petri dishes. This
will hopefully get the stem cells to develop into a certain type of tissue,
muscle, or other cell. But there is still a long way to go. In order to make
this occur within the Petri dish, a signal needs to be given to the cells and it
is this signal that researchers are still trying to create to get the process
But, if these challenges can be overcome and scientists can find a way to
control and manipulate the stem cells once they are injected, the benefits of
stem cells are immeasurable!
The first way that stem cells could be used is to
test new medications. Today these medications need to go through rigorous
testing and clinical trials, which take a lot of time and money. However, stem
cells could replace this to test the safety and effectiveness of these new
medications. For instance, cancer medication could be applied onto stem cells
that have tumor growth on them. The cells can then be studied to see if the
medication stops the tumors from growing, and if the cells have any adverse
effect on the stem cells.
Of course, stem cells could also be used to
recreate damaged cells and inject them into a patient to treat them for a
disease or medical condition. But scientists want to expand on this idea even
more and be able to eventually produce entire organs right in a laboratory
setting. Imagine what a medical breakthrough this could be with people no longer
being on mile-long wait lists while they wait for a transplant for a heart,
kidney, or other type of organ.
So Why the Controversy?
With all the fabulous medical advancements that stem
cells seem to be creating, why would anyone fight the development and production
of them? The reason is that stem cells cannot be made on their own and that they
must be taken from embryos. And in order to do that, the embryo must be
destroyed. Although the embryos are only three to five days old when this
happens, some religious and pro-life activists argue that this is the
destruction of human life. Even though that life is still only a clump of cells
in a dish, if it’s not destroyed for stem cells, it could grow into being a
human being. The argument is that taking a human life for any reason is wrong.
The other argument against sperm cell research is
that it makes cloning problem. Although this was always at the back of the minds
of those that opposed stem cell research, the fear became a reality in 1997,
when researchers in Scotland were able to clone a sheep, that they named Dolly.
The thought is that if researchers can clone a sheep they can also clone a human
being. The problem with this is that arguers state that people should not be
allowed to play God, and dictate what life is given. Also, another fear with
cloning humans is that researchers and scientists might try to create
superhumans. These humans might have greater intellectual abilities than even
the brightest minds, or have superhuman strength that could pose a real danger
to today’s society.
Scientists are also doing a lot to reduce the fears
that people associate with stem cell research. One thing they are doing is
working more with adult stem cells so that embryos needn’t be destroyed in the
process of research. While these stem cells are more difficult to obtain and
manipulate, advances are being made in this area as well to make them more
workable and flexible. However, because there are still many advocates against
stem cell research, the research is now being heavily monitored by governments
across the world. Stem cell funding is also restricted to appease the