Stem Cells
What makes stem cells unique is their capacity to divide indefinitely and differentiate along different pathways, which is necessary in embryonic development. This is also what makes stem cells useful for therapeutic uses.
There are primarily two types of stem cell: embryonic and adult stem cells.
Embryonic stem cells are the first cells that are created after fertilization when the zygote splits into two for the first time. These in specific have an immense capacity to divide again and again to produce copious quantities of new cells. And also, more importantly, they are yet not defined and therefore can potentially become any of the 200 different cells types that exist in the human body. These are known as totipotent because of this capacity.
Embryonic stem cells are therefore potentially very useful. These could produce new specifically wanted biological tissues in order to serve as a replacement to damaged or missing ones of an individual.
Even though the use of embryonic stem cells could make medicine flourish, it does present some ethical issues. Some of these for instance are that embryonic cells, due to their great dividing capacity, could form tumors. This would put a patient at great risk especially when the treatment is only being tested.
Another downside to embryonic stem cells is that these cells do in fact come from another individual and could be rejected by the receiver.
I completely agree that these two factors are an issue, not until doctors know how to safely control these cells they shouldn´t be using them openly on patients.
On the other hand I do not agree with the ‘ethical issue’ that using these for treatment is killing an embryo. Embryonic stem cells are obtained from IVF leftover embryos. By using these for science we are actually making a use of these cells, otherwise they would be thrown away since they are an excess and waste product.
Adult stem cells do not have the same capacity as embryonic stem cells. These are only pluripotent instead of totipotent. Their dividing capacity is much more limited. In the bone marrow and skin they are capable of duplicating themselves in order to replace damaged tissue. Whereas in areas such as the brain, it can only produce a limited amount of repairs.
Ideally, cord blood stem cells would be the best solution. These do not have many ethical issues, like embryonic stem cells do, but are much more functional than the adult ones.
The only issue is that these have to be obtained as soon as an individual is born in order to obtain them from the umbilical cord. Adults that haven’t obtained these cells at birth do not have any other way to recruit them.
Setting aside the fact of the potential issues using stem cells, they are still currently being used. Two examples for which stem cell therapy is used are Stargardt’s disease and Leukemia.
Stargardt´s Disease
(stargardts macular dystrophy)
This disease is genetic that develops when the individual is between the ages of 6-12. Most cases are due to the mutation of a gene called ABCA4. As a consequence retina cells are damaged and vision gets progressively worse and can potentially completely be lost.
With embryonic stem cells scientists were able to produce retina cells. The method was first tested on mice suffering a similar condition. The experiment worked successfully. In 2010 the method was approved to be used on humans.
They injected 50000 retina cells into a 50 years old suffering stargardts disease. These attached themselves effectively, improving the patient’s vision, and no negative side effects emerged.
Even so the stem cells treatment is still under provision. There has been approximately only 13 people which have received the treatment as a participation in the study.
Leukemia
Leukemia is a type of very dangerous cancer. Like all cancers, it is caused by mutations in the cells and specifically affects the way that they divide (the cell cycle). In leukemia, white blood cells mutate and far too many are produced.
The procedure to heal a patient with stem cell therapy goes as follows:
Thanks to the capacity of regenerating themselves, the stem cells in the blood will be able to multiply themselves into the right number of red and white blood cells, since all the cancerous ones will have been killed in chemotherapy.
What makes stem cells unique is their capacity to divide indefinitely and differentiate along different pathways, which is necessary in embryonic development. This is also what makes stem cells useful for therapeutic uses.
There are primarily two types of stem cell: embryonic and adult stem cells.
Embryonic stem cells are the first cells that are created after fertilization when the zygote splits into two for the first time. These in specific have an immense capacity to divide again and again to produce copious quantities of new cells. And also, more importantly, they are yet not defined and therefore can potentially become any of the 200 different cells types that exist in the human body. These are known as totipotent because of this capacity.
Embryonic stem cells are therefore potentially very useful. These could produce new specifically wanted biological tissues in order to serve as a replacement to damaged or missing ones of an individual.
Even though the use of embryonic stem cells could make medicine flourish, it does present some ethical issues. Some of these for instance are that embryonic cells, due to their great dividing capacity, could form tumors. This would put a patient at great risk especially when the treatment is only being tested.
Another downside to embryonic stem cells is that these cells do in fact come from another individual and could be rejected by the receiver.
I completely agree that these two factors are an issue, not until doctors know how to safely control these cells they shouldn´t be using them openly on patients.
On the other hand I do not agree with the ‘ethical issue’ that using these for treatment is killing an embryo. Embryonic stem cells are obtained from IVF leftover embryos. By using these for science we are actually making a use of these cells, otherwise they would be thrown away since they are an excess and waste product.
Adult stem cells do not have the same capacity as embryonic stem cells. These are only pluripotent instead of totipotent. Their dividing capacity is much more limited. In the bone marrow and skin they are capable of duplicating themselves in order to replace damaged tissue. Whereas in areas such as the brain, it can only produce a limited amount of repairs.
Ideally, cord blood stem cells would be the best solution. These do not have many ethical issues, like embryonic stem cells do, but are much more functional than the adult ones.
The only issue is that these have to be obtained as soon as an individual is born in order to obtain them from the umbilical cord. Adults that haven’t obtained these cells at birth do not have any other way to recruit them.
Setting aside the fact of the potential issues using stem cells, they are still currently being used. Two examples for which stem cell therapy is used are Stargardt’s disease and Leukemia.
Stargardt´s Disease
(stargardts macular dystrophy)
This disease is genetic that develops when the individual is between the ages of 6-12. Most cases are due to the mutation of a gene called ABCA4. As a consequence retina cells are damaged and vision gets progressively worse and can potentially completely be lost.
With embryonic stem cells scientists were able to produce retina cells. The method was first tested on mice suffering a similar condition. The experiment worked successfully. In 2010 the method was approved to be used on humans.
They injected 50000 retina cells into a 50 years old suffering stargardts disease. These attached themselves effectively, improving the patient’s vision, and no negative side effects emerged.
Even so the stem cells treatment is still under provision. There has been approximately only 13 people which have received the treatment as a participation in the study.
Leukemia
Leukemia is a type of very dangerous cancer. Like all cancers, it is caused by mutations in the cells and specifically affects the way that they divide (the cell cycle). In leukemia, white blood cells mutate and far too many are produced.
The procedure to heal a patient with stem cell therapy goes as follows:
- A sample of blood, containing adult stem cells, is removed from a large bone.
- Chemotherapy kills the excess white blood cells.
- The extracted blood is re-introduced into the patient.
Thanks to the capacity of regenerating themselves, the stem cells in the blood will be able to multiply themselves into the right number of red and white blood cells, since all the cancerous ones will have been killed in chemotherapy.