Hello and welcome to this lesson from the unit, stem cells and differentiation.

The title of today's lesson is using stem cells in medicine, potential benefits, risks, and ethical issues.

So we'll be looking into some examples of where research is being done into the use of stem cells, in some cases that has led to treatments, what the potential benefits of using stem cells are, but also the risks associated with that, and the ethical issues, whether it's right or wrong, how people feel about using stem cells, but also any clinical issues with using those two.

My name's Mrs. Barnard.

And I'm going to be taking you through today's lesson.

So by the end of today's lesson, you should be able to describe examples of how embryonic and adult stem cells could be used in medical treatments, including potential benefits, risks, and ethical issues.

And with all our lessons, we've got quite a few key terms. And our key terms for today's lesson are embryonic stem cell, adult stem cell, specialised cell, immune rejection, and ethical.

So what I'll do is I'll leave this slide up so you can pause the video if you wanna write those down.

But otherwise we'll be going through those definitions as we go through today's lesson.

Okay, so our lesson today is in two parts, stem cell uses in medicine and also in research before they work their way into treatments.

And then we're gonna look at weighing up the benefits, the risks, and the ethical issues associated with their use.

So let's get started with the first part of today's lesson, which is stem cell uses in medicine.

So just a little bit of a reminder for you.

There are two types of human stem cell.

They're the embryonic stem cells, and they can differentiate into any type of specialised cells.

So these are the first cells that form.

So when an egg is fertilised, we get a zygote.

And that is a single cell.

That cell will quite quickly undergo mitosis, making copies of itself.

But those cells all have the potential to become any type of cell in the body.

So here's a few examples of what an embryonic stem cell could become.

So it could become cardiac muscle cells, which are the muscle cells that are in your heart.

It could be red blood cells, which are the blood cells that carry oxygen.

It could be epithelial cells, which are those lining cells that, this particular image is of the ones on the surface of your skin, from your cheeks this one is, or neurons, which are those cells that make up the nervous system.

So they're all through the body, but this particular picture is from the spinal cord.

So that's just some examples of some specialised cells that embryonic stem cells can become.

The other type of stem cell is adult stem cells.

And adult stem cells can differentiate into a limited number of related specialised cells.

And they are only in certain regions of the body.

So we can see here examples of where you could find adult stem cells in the body.

So the brain and the eyes, the skin and the blood, the liver and the heart, and the muscle and the bone marrow.

Here's an example of what an adult stem cell could differentiate into.

So if we've got an adult stem cell here in the skin, there are different layers of tissue in the skin, and each of them have a different type of specialised cell.

So an adult stem cell in the skin could differentiate into epithelial tissue, which is the layer right on the top; the smooth muscle, which allows the movement of the skin, contraction and dilation; and then we've got fat tissue, which is an energy storage and insulation.

So we've got all of these layers within our skin.

And those stem cells can differentiate into those.

So you can see they're in a limited region in the body, this particular stem cell in the skin.

And it differentiates into specialised cells that are sort of related to each other.

So time for a quick check.

Choose the two sources of stem cells for use in medicine.

So pause the video while you decide, and then I'll let you know if you've got it right.

Okay, then.

So the two sources of stem cells for use in medicine are adult stem cells and embryonic stem cells.

So well done if you got that right.

So let's move on.

So embryonic stem cells can be taken from a five-day-old embryo before differentiation has occurred.

So as I already described, when we get that fertilisation and we get that one cell, that zygote, that's undifferentiated, it starts to divide.

So we have this ball of cells.

It doesn't take long just after the five days that those cells start to differentiate into other types of cells.

So if we're going to use embryonic stem cells in medicine, then it's really important that those are cells are taken before differentiation has started to take place.

So where do we get these embryos from? So embryos can source them from IVF clinics.

So when people undergo IVF, they make embryos.

So sperm and egg are put together in order to form a zygote, and then that zygote is left to divide.

So some of those embryos will be implanted into the mother's uterus, but some of them will be frozen just in case the couple want to use them again in the future.

But if they are no longer required, then the couple can choose whether they want to have them destroyed or whether they can be donated.

So that's where embryos can be sourced from for stem cells.

So in the lab, the stem cells can then be differentiated to divide into many types of specialised cells.

So given the correct chemicals that can stimulate them to divide into different types of cells.

And then those cells can be used to treat disease, genetic disorders, or injuries.

So we have our embryonic stem cell, differentiation is stimulated, and then we get a specialised cell.

So here's an example of where it could be used.

Now, you might have heard about diabetes before.

So diabetes is a condition where certain cells in the pancreas are destroyed.

They're actually destroyed by a person's own immune system.

So it's not something that can be helped in type 1 diabetes or controlled by lifestyle factors.

So it means that the patient can't control their blood sugar level.

And that's quite dangerous 'cause it can lead to other long-term consequences.

Now, the cells in the pancreas that are destroyed are called beta cells.

And the beta cells are the ones that make the insulin.

So what we can do is that we can replace those beta cells with stem cells that have been differentiated to form beta cells.

So as scientists are researching a potential treatment, embryonic stem cells are stimulated to differentiating into beta cells, and then they could potentially be transplanted into a pancreas.

So we can see that in this image that we've got these embryonic stem cells, they can be stimulated to differentiate, then the beta cells, and then they go into the pancreas.

And there's just an image there just to make sure that you know where the pancreas is.

Okay, here's another example.

Again another disease you might have heard of, called multiple sclerosis.

Now that's a condition in which the myelin sheath around the axon of neurons is damaged.

So just a quick recap.

In neurons, you've got the cell body, and then you've got this long axon, looks like a bit like a tail, but a long axon that comes down from it where the electrical impulses that allow signals to be carried around the body travels down there.

Now, wrapped around that are these cells which give it a fatty layer, and that insulates that electrical impulse.

So what happens is if that starts to break down, and again this is a condition that's often caused by your own immune system attacking your neurons.

So it's an autoimmune disease.

Then that means that those electrical signals, those impulses that are being carried along the axon, are slowed down because it's not insulated.

And that affects the way that somebody with multiple sclerosis can control their own body.

So if you have damage to the brain and the spinal cord, neurons that are affected can be permanently damaged, and then they can affect the functioning of your body.

The reason for that is if you damaging neuron, it doesn't really divide by mitosis.

So you know if you cut your skin and you get a scab that forms over that, then your skin cells will differentiate, make new skin cells, and then your skin heals up.

The problem is with neurons, that they don't really undergo mitosis, which means if you damage them, you can't easily have them replaced by new cells that have divided.

So therefore, stem cells are really important in treating injuries that have affected the brain and the spinal cord.

So scientists are in the process of researching how we can use stem cells, from embryonic stem cells, in order to treat these injuries.

So time for a quick check.

Couple of big examples there.

Diabetes, multiple sclerosis, and injuries.

So in the procedure below, which one of these is a specialised cell? So pause the video, and then when you come back, we'll see if you've got it right.

Okay, so which one was the specialised cell? Was it the five-day-old embryo, the embryonic stem cell, or the neuron? And the correct answer is the neuron.

So hopefully everybody got that right.

Okay, so adult stem cells can also be potentially used as treatments, so not just embryonic stem cells.

So let's have a look at some examples for adult stem cells.

So all blood cells that we have are made from adult stem cells that are in our bone marrow.

So our bones are actually hollow.

So they're not solid all the way through.

And in the middle, we've got this living tissue.

And that tissue is made up of lots of different cells.

So you can see in this image here, if you zoom in, what it's made up of.

So we've got these bone marrow stem cells that are gonna differentiate into other types of cells.

We've got red blood cells in there that you'll be familiar with, white blood cells that are involved in our immune response.

Also, some fat cells, which are those big yellow ones.

Okay? But what we're interested in is those bone marrow stem cells, okay? So leukaemia, again another disease you might have heard of, is a type of cancer.

And that results in faulty blood cells being made.

Okay? So the stem cells are not making the correct blood cell.

So adult stem cells can be taken from a donor's bone marrow, and then they can be used as a treatment.

So they can be treated to differentiate it from the right kind of cells for the patient, okay? So where do we get these from? Where do we get these adult stem cells from? People donate them.

It's a very kind act.

And there are charities that really promote the opportunity for people to give stem cells.

It is a surgical procedure.

And you can see in this image here what they do.

So they have to go into the bone 'cause that's where they are.

And you can see they go into the top here by the pelvis.

And they extract some of those adult stem cells from there in that procedure.

So then these stem cells can then be directly transplanted into a patient that's got leukaemia, and then that will replace their faulty bone marrow stem cells.

So time for a quick check.

True or false.

Adult stem cells are used in treatments for leukaemia.

So pause the video while you decide whether this is true or false.

But then also decide which of these statements you think best justifies your answer.

And then when you come back, we'll see if you've got it right.

Okay, adult stem cells are used in the treatments for leukaemia.

This is true.

And the statement that best justifies this is that they are used to replace blood cells that have been damaged by the disease.

So if you've got those right, then well done.

So adult stem cells can be donated as we've said, or we can harvest them from a patient's own cells.

Another source of stem cells is in a process called therapeutic cloning.

Now, therapeutic cloning takes place when you take an egg cell.

So the egg cell comes from a donor.

So you can see that that is the grey one there.

So that's from the donor.

Now, we don't want the nucleus, which is the genetic information of the donor as part of our stem cell.

So what we do is we remove the nucleus, and now you've got an empty egg cell, okay? And then what you're gonna do is you're going to take the patient's own body cell, and you're gonna take a nucleus out of it, and the nucleus will then contain all the genetic material, all the DNA and the genetic code from the patient.

And you put that nucleus into the empty X cell.

Once you have this cell then with its new nucleus in, you can then get it to divide, and it will form an embryo.

And that embryo will be made up of cells where all of the DNA comes from that patient.

So it hasn't been mixed with anybody else's DNA.

It's not half and half.

So those M cells will be genetically identical to the patient.

So once you've formed an embryo, then you can remove the stem cells, again at that five-day stage before they start to differentiate.

And then you can use those stem cells to treat the patient because they're not going to reject them in the same way because they're from their, they have the same genetic information.

So time for a quick check.

Choose the conditions that stem cells could be used to treat.

So again, pause the video, and then when you come back, we'll see if you've got it right.

Okay, so stem cells could be used to treat spinal cord damage, diabetes, but not malaria and not measles.

Both of those are infectious diseases caused by pathogens.

So if you've got that right, then well done.

Okay, time for a practise task now.

So we've given you loads of different examples of where stem cells are being used in research or potential treatments.

And so the first line of our practise task is stem cells could potentially be used to treat a number of disorders, in addition to those examples that we've already seen.

I would like you to carry out some research into Parkinson's disease and to write a summary of the use of stem cells in their treatment.

So what I would like you to include after you have done some research is some basic details of the condition.

So what is Parkinson's? What are its symptoms? What are the long-term effects? The process, so the process of using stem cells.

So how could we use them? And then any outcomes that have so far been achieved in research.

Okay, you'll need a little bit of time to do this.

This is quite an involved task.

But when you come back, I'll show you an example of what your work could look like.

Okay, time to pause the video.

Okay, I wonder how you got on with that.

It was quite an involved task in terms of research.

You might have looked at other disorders and diseases instead.

But here's our example for Parkinson's.

So Parkinson's disease causes the destruction of neurons which helps to control movement and mood.

Embryonic stem cells can be used and differentiated into neurons.

The neurons are then transplanted into the brain of a patient with Parkinson's disease.

And the outcomes they've got so far is that there has been improvements in symptoms, but research still continues.

Now, you might have more than that, but those are some of the basics that answer the question of the task.

All right, time to move on to the second part of our lesson, which is the benefits, risks and ethical issues.

So there's lots of potential uses of stem cells, many of which we've already talked about.

And they are the subject of lots of research.

However, the full extent of what we can use them for is still not known.

So lots of research is still on its way.

However, in some cases, stem cells have been used to help patients with currently untreatable conditions.

So that's quite amazing.

If a condition has no treatment and you can improve their symptoms. It has been used to grow organs like skin for transplants, for example, if somebody's been really badly burned, not having any skin is a real risk of infection.

So being able to grow skin, particularly if you can use the person's own stem cells and that process that we just looked at in therapeutic cell cloning.

That means that you wouldn't risk rejection, and you can make skin for that person to help them combat infection or stop infection.

It can also be used to reduce symptoms of progressive diseases.

So diseases we've talked about like Parkinson's which will progress and multiple sclerosis over time, and it can reduce the symptoms and slow down that process.

They can also be used in research.

So sometimes it's not about putting the cells back into the patient.

It's about seeing the effect of drugs and vaccines and other treatments on the cells as they are in lab-based conditions so that we can see how the cells respond to those particular drugs.

It also allows us to look for things like toxicity.

So whether the cells will immediately, you know, stop functioning if you use that particular drug or vaccine.

So adult stem cell transplants are a treatment for leukaemia, as we've already talked about.

And in using a patient's own stem cells, so by therapeutic cloning, this prevents immune rejection because the cells are all genetically identical to the patient, and therefore body with the immune system would recognise it itself.

So therefore the body wouldn't reject them.

And in this case, we would remove the stem cells from the patient, and they would be stimulated to divide, and then they would be genetically identical to the patient.

So then we could use them in treatments.

So we use this term immune rejection.

And the reason that that is important is because the immune rejection is when the body recognises, or the immune system recognises, that there's pathogens or cells in the body that don't belong in the body.

And the immune system recognises this because there'll be markers on the surface of the cells that indicate that they're not cells.

The immune system will try to attack them.

And we don't want that to happen if something's been transplanted.

So people who do have a transplant have to take medication to sort of suppress their immune systems. They're called immunosuppressants.

And the risk of taking immunosuppressants is that you can get infections from other sources like other pathogens.

So it does make you a more high risk person from that point forward.

So stem cells from a close relative can be used if the patient's own stem cells are faulty.

But if they do, a person has to take immunosuppressants.

And this makes the patient more susceptible to other infections.

So it would be good if they could use their own stem cells which are genetically identical.

So if you can select from this list, please, the current uses of stem cells.

So pause the video while you do that.

And then we'll come back and we'll see if you've got it right.

Okay, so the correct uses of stem cells at present are to grow tissues and organs for transplant, to replace cells that have been damaged by drug treatments, and to replace cells damaged by diseases.

So if you've got that right, then well done.

Next one, true or false.

It is more effective to use a donor rather than a patient's own cells for stem cell transplants.

If you think that's true, then justify your answer with one of the statements below.

And if you think it's false, then choose one of the statements that would justify that below.

So pause the video while you decide.

Okay, so it is more effective to use a donor rather than the patient's own stem cells for transplants.

That is false, because a donor is genetically different, so their cells may be rejected by the patient's immune system.

So if you chose that one, then well done.

So the use of embryos for stem cells in therapeutic colonial raises some ethical issues.

Now, you might have heard of this word before.

Now in this context, an ethical issue relates to whether an action and its consequences could be considered right or wrong.

And different people would have different views on this.

The embryos used in medical research are those that would've been destroyed as medical waste.

They are also though the first stage of development of a human being.

So you would go from an embryo through differentiation and growth to a foetus.

And certain individuals and groups will have differing opinions on when life begins.

And using embryos for IVF or making them in therapeutic cloning risks them being seen as a commodity.

So instead of each embryo being seen as the potential for life, it might just be seen as something that could easily be made and bought and sold.

In the UK, the Human Fertilisation and Embryology Authority, they oversee the use of gametes and embryos.

So there's strict rules and regulations about the using them, who can use them, and their growth, and development in lab conditions.

The owners of the gametes of that embryo must consent to an embryo's use.

And embryos cannot be developed in a lab for more than 14 days.

They can be frozen before that point and used later, but they can't be developed for more than 14 days.

There are also some clinical issues, so not necessarily ethical issues, but clinical issues that limit the use of stem cell technology.

And those are things like the success rate for therapies.

It does really vary between people.

So it's not a quick win for everybody.

Getting hold of stem cells is quite limited, okay, because as we said, you can't just make embryos.

They have to be used as a waste product.

And there is difficulty in recruiting stem cell donors, as you might imagine, because we looked at it is a surgical procedure and people may not want to volunteer for that.

And stem cells do have a higher rate of mutations that lead to cancer.

So in a lot of research that's been done into stem cells, what they've found is cancer developing from those stem cells because they do have a very good ability to divide stem cells more than other cells.

And the other thing is that viruses can spread between the stem cells even before that they've been used for transplant, so in lab-based conditions.

There's also some problems with society's understanding and opinion of the use of stem cells.

So support for the research and the use of stem cells does require education.

So for people to know what stem cells are and what their uses are and why they're important.

And the public needs to know what the benefits are and where the current research is.

So it's not really clear whether the benefits at the moment outweigh the risks and the ethical objections.

And a lot of research is being carried out by clinics that make profit.

So therefore it could mean that some patients have their hopes raised are exploited for money.

So time for a quick check.

Which of these is an ethical issue with using stem cells in medicine? So pause video while you decide.

And then we'll come back and we'll check if you've got it right.

Okay.

So which of these is an ethical issue? So using an adult's own stem cells to avoid immune rejection is not one.

Lack of public understanding is not ethical.

But objections to the use of embryos is ethical.

Varied success rates of treatments is not ethical.

So Laura and Andeep describe how to write an evaluation.

So we've got a practise test now.

And you've probably come across this word evaluation before.

They are looking at an application of science, such as the use of stem cells.

And Laura says, "An evaluation must state some uses and describe them with scientific detail." And Andeep says, "An evaluation must give both pros and cons." So what I would like you to do is to write an evaluation of the use of stem cells in medicine.

I'd like you to include some of the scientific ideas behind their use, and also discuss the benefits, risks and possible issues.

So this, again, is an extended piece of writing.

So it's gonna take you a little bit of time.

So when you come back, we will have a look at a model answer.

Okay, let's see how you got on with that.

Then let's have a look at a model answer.

So we're writing an evaluation of the use of stem cells in medicine.

So stem cells are undifferentiated cells.

Embryonic stem cells can differentiate into any specialised cell, and adult stem cells can differentiate it into a limited number.

So we're stating our scientific detail there.

Then we move on.

Stem cells can be stimulated then to differentiate into specialised cells and then can be used to replace those that have been damaged in treatments, like in leukaemia.

And the specialised cells can also be used to test drugs for some conditions, like heart disease.

The use of embryos raises ethical concerns as an embryo is the first stage in human development.

There are also issues to consider, such as profit making from vulnerable patients and a lack of understanding of the potential use and limits of stem cells in medicine.

Stem cells have a higher rate of mutations that can lead to cancer, and viruses can spread between stem cells in culture.

Okay, so if you've got at least some of those points, then well done.

Hopefully you manage to write in depth.

Okay, guys, that brings us to the end of our lesson.

So using stem cells in medicines: potential benefits, risks and ethical issues.

So embryonic and adult stem cells can be used in treatments to make new specialised cells to replace damaged ones.

They can also be used to test drugs for toxicity.

Examples of the uses include bone marrow transplants for leukaemia and potential treatments for type 1 diabetes and multiple sclerosis.

Transplanting stem cells into a patient has risks including immune rejection if they are not the patient's own cells, infection with viruses and cancer due to mutations and uncontrolled cell division.

There are ethical objections to using embryos as a source of embryonic stem cells.

And when evaluating the use of stem cells in medicine, we must consider whether benefits outweigh risks and ethical issues.

So well done for your work in today's lesson.

And we will see you soon.