Stem Cells Flashcards
What are Stem Cells?
Unspecialised cells that have the ability to self-renew and divide to replenish lost cells without limit.
Potential to develop into many different cell types in the body, during early life and growth
Under the right conditions in the body or a laboratory, stem cells divide to form more cells called daughter cells.
What can happen when stem cells divide?
When they replicate, it produce two stem cells that has the potential either to remain a stem cell or become another type of cell with a more specialised function, eg. muscle cell, red blood cell
State an important characteristic, that distinguish it from other cell types?
Unspecialised cells capable of renewing themselves through cell division
Only under certain physiologic or experimental conditions
Give examples to why replication occurs only under certain physiologic or experimental conditions. (Bone marrow/Gut and pancreas/heart
Gut and bone marrow, etc
Stem cells regularly divide to repair and replace worn out or damaged tissue
Pancreas and heart etc..
divide under special conditions
What are the 4 types stem cells?
Somatic (Adult stem cell)
Embryonic
Umbilical
Peripheral blood
What are somatic stem cells?
Exist naturally in the body
It is important for growth, healing, replacing cells that are lost through daily war and tear
Produce all different cell types that make up our blood
What can somatic stem cells be used for? (2) advantage/disadvantage
Stem cells from the blood and bone marrow are routinely used as a treatment for blood related diseases.
Natural circumstances, they become only a subset of related cell types. Partial differentiation can be an advantage when you want to produce blood cells. A disadvantage is the inability to producing an unrelated cell type
What are 3 special conditions for Somatic stem cells?
Present in low abundance and are difficult to isolate and grow in culture.
Isolation of some types could cause considerable tissue or organ damage, as in the heart or brain.
Somatic stem cells can be transplanted from donor to patient, but without drugs that suppress the immune system, a patient’s immune system will recognise transplanted cells as foreign and attack them.
What are the ethical considerations with somatic stem cells?
Therapy involving somatic stem cells is not controversial; however, it is subject to the same ethical considerations that apply to all medical procedures.
What are Embryonic stem cells?
Formed as a normal part of embryonic development. They can be isolated from an early embryo and grown in a dish.
What is the potential of Embryonic stem cells?
potential to become any type of cell in the body, making them a promising source of cells for treating many diseases.
What is a special considerations for Embryonic stem cells?
Without drugs that suppress the immune system, a patient’s immune system will recognise transplanted cells as foreign and attack them.
What is a ethical considerations with Embryonic stem cells?
isolate human embryonic stem (hES) cells in the lab, they destroy an embryo
What are the 5 special steps for iPS stem cell differentiation in medical treatment. I T W P D
Isolate Treat Wait Pluripotent Differentiate
Describe the 1st step of iPS stem cell differentiation in medical treatment. (I)
Isolate cells from patient (skin or fibroblasts) grown in a dish
Describe the 2nd step of iPS stem cell differentiation in medical treatment. (T)
Treat cells with ‘reprogramming’ factors
Describe the 3rd step of iPS stem cell differentiation in medical treatment. (W)
Wait a few weeks
Describe the 4th step of iPS stem cell differentiation in medical treatment. (P)
Pluripotent stem cells
Describe the 5th step of iPS stem cell differentiation in medical treatment. (D)
Change culture conditions to stimulate cells to differentiate into a variety of cell types
What are four difficult questions raised for Embryonic stem cells?
Does life begin at fertilisation, in the womb, or at birth?
Is a human embryo equivalent to a human child?
Does a human embryo have any rights?
Might the destruction of a single embryo be justified if it provides a cure for a countless number of patients?
Since ES cells can grow indefinitely in a dish and can, in theory, still grow into a human being, is the embryo really destroyed?
What are iPS stem cells (Induced Pluripotent Stem Cells)?
created artificially in the lab by “reprogramming” a patient’s own cells. iPS cells can be made from readily available cells including fat, skin, and fibroblasts (cells that produce connective tissue).
What can iPS stem cells do?
become any cell in the body
iPS cells can be made from a patient’s own cells, there is no danger that their immune system will reject them.
What are 2 special conditions for iPS stem cells treatment?
much less expensive to create than ES cells generated through therapeutic cloning
“reprogramming” process introduces genetic modifications, the safety of using iPS cells in patients is uncertain.
State the 5 steps of Isolating ES cells?
J D R G D
Joining Development Remove Grow Differentiation
Describe the 1st step of Isolating ES cells. (J)
Sperm and egg join
Describe the 2nd step of Isolating ES cells. (D)
Embryo develops for 5-7 days into a Blastocyst
Describe the 3rd step of Isolating ES cells. (R)
Remove the inner mass of the Blastocyst
Describe the 4th step of Isolating ES cells. (G)
Grow in a dish
Describe the 5th step of Isolating ES cells. (D)
Change culture conditions to stimulate cells to differentiate into a variety of cell types
What is Therapeutic cloning?
creating patient-specific embryonic stem (ES) cells.
State 2 statement of the potential as the therapy of therapeutic cloning.
Generate ES cells with the potential to become any type of cell in the body.
In addition, since these cells are made from a patient’s own DNA, there is no danger of rejection by the immune system.
What are some special considerations for therapeutic cloning?
time consuming, inefficient, and expensive.
What are some ethical considerations for therapeutic cloning?
Involves in creating a clone of a human being and destroying the cloned embryo, and it requires a human egg donor.
What are 6 steps of Creating ES cells through therapeutic cloning (somatic cell nuclear transfer)? I R T R S I
Isolate Remove Transfer Reprogram Stimulate Isolate
Describe the 1st step of Creating ES cells through therapeutic cloning (I)
Isolate cells from patient
Describe the 2nd step of Creating ES cells through therapeutic cloning (R)
Remove nucleus from an egg cell
Describe the 3rd step of Creating ES cells through therapeutic cloning (T)
Transfer nucleus (contains DNA) from the patient’s cells to the egg.
Describe the 4th step of Creating ES cells through therapeutic cloning (R)
Egg cell reprograms the patients DNA
Describe the 5th step of Creating ES cells through therapeutic cloning (S)
Stimulate the cell to begin dividing, let develop to the blastocyst stage
Describe the 6th step of Creating ES cells through therapeutic cloning (I)
Isolate the inner cell mass from the blastocyst and grow it in a dish
What is the source of somatic stem cells?
Bone marrow
What is the source of Peripheral Blood stem cells?
Bloodstream
What is the source of Umbilical cord stem cells?
Umbilical cord
What is Somatic Stem Cell Therapy?
Using a Bone Marrow Transplant to Cure Leukemia
What is leukemia? (2)
Cancer of white blood cells, or leukocytes. Mature leukocytes are released into the bloodstream, where they work to fight off infections in our bodies.
Leukemia results when leukocytes begin to grow and function abnormally, becoming cancerous. These abnormal cells cannot fight off infection, and they interfere with the functions of other organs.
How is Leukemia treated successively?
getting rid of all the abnormal leukocytes in the patient, allowing healthy ones to grow in their place.
What are the two ways abnormal leukocytes can be removed?
Chemotherapy
Bone marrow transport
Describe what chemotherapy does to leukocytes
One way to do this is through chemotherapy, which uses potent drugs to target and kill the abnormal cells. When chemotherapy alone can’t eliminate them all, physicians sometimes turn to bone marrow transplants.
Describe what Bone marrow transplants does to leukocytes
patient’s bone marrow stem cells are replaced with those from a healthy, matching donor.
All of the patient’s existing bone marrow and abnormal leukocytes are first killed using a combination of chemotherapy and radiation.
Next, a sample of donor bone marrow containing healthy stem cells is introduced into the patient’s bloodstream.
What happens when Bone marrow transplant is successful?
the stem cells will migrate into the patient’s bone marrow and begin producing new, healthy leukocytes to replace the abnormal cells.
What are Peripheral blood stem cells?
sed just like bone marrow stem cells to treat leukemia, other cancers and various blood disorders.
How are Peripheral blood stem cells obtained?
obtained from drawn blood
a less invasive treatment option than bone marrow stem cells.
PBSCs are sparse in the bloodstream, however, so collecting enough to perform a transplant can pose a challenge.
What are Umbilical cord blood stem cells?
the stem-cell–rich blood found in the umbilical cord has proven useful in treating the same types of health problems as those treated using bone marrow stem cells and PBSCs.
Why are Umbilical cords less prone to rejection than either bone marrow or peripheral blood stem cells? (2)
This is probably because the cells have not yet developed the features that can be recognised and attacked by the recipient’s immune system.
Also, because umbilical cord blood lacks well-developed immune cells, there is less chance that the transplanted cells will attack the recipient’s body, a problem called graft versus host disease.
What is the difference between stem cell and differentiated cells?
It is reflected in the cell’s DNA
In a stem cell, the DNA is arranged loosely, with its genes ready to spring into action. As signals enter the cell and differentiation begins, genes that will not be needed are shut down, and genes that will be required for a specialized function remain open and active.
How can iPS cells be reversed? (differentiated to stem)
Introducing just 4 of these genes back into differentiated cells made them behave like stem cells. The genes appear to be remodelling the cells’ DNA, unlocking the genes that were shut down during differentiation.
How can STAP cells be reversed? (differentiated to stem)
By stressing them.
This surprisingly simple process, they claimed, quickly and efficiently generates stem cells without using any kind of genetic manipulation.
Didn’t hold up under scrutiny, and they ended up retracting their articles. iPS cells and other types of stem cells, however, are real.
What can stem cells be implanted for?
Plastic surgery
Either embryonic or adult stem cells, it offers possibility of creating natural implant materials for reconstruction
Eg. Replace a breast, Fill in facial tissue after cancer, reduce wrinkles
What can Neural stem cells treat?
That Parkinson disease and other forms of neurodegeneration or traumatic damage to the CNS
