Genetics/Embryonic stem cell therapy for cardiacmyogenesis
I have read many research papers on using embryonic stem cells for replacing damaged heart cells in human.
However, I still don't understand why using embryonic stem cells as source is better than using bone marrow or other type of stem cells in clinical use.
Besides, i don't understand why they say that using embryonic stem cell will cause immunorejection, since we just use patient's stem cell + enucleated eggs for generating the stem cells(is it called "somatic cell transfer"?
On the other hand, with regard to the general mechanism, I would like to ask if my concept is right or wrong. First the enucleated egg fused with patient cell, with some stimulating factors (growth factors, esp for cardiac muscle cells grwoth) stimulate the cell to form embryonic stem cell --> cultre --> selection of pure cardiac muscle cells from heterogenous mixtuer of ES cells --> inject into patient's heart?
However, i aslo read from researches that there are a number of stimulating factors, selection process (selection marker, fluorense) and injection method(directly to heart. veins)
Thanks you for your help. I don't really know if my concept is right or wrong. Thanks!!
Answering the first part of your question:
".....don't understand why using embryonic stem cells as source is better than using bone marrow or other type of stem cells in clinical use".
Embryonic stem cells are Pluripotent as opposed to adult stem cells like marrow cells. The latter have a lot of stem cell characteristics and can become a variety of tissues. However it cannot create an embryo. Therefore it is not "totipotent".
Your second half of the question: "using embryonic stem cell will cause immunorejection, since we just use patient's stem cell + enucleated eggs for generating the stem cells(is it called "somatic cell transfer"?
This approach is only an instance where cloning of an organism is the goal. As for rejection, this has nothing to do with what happens in cloning. In cloning you are dealing with a single cell. In immunorejection, you are transferring stem cells to an entire organism where immune reaction can be triggered by non-compatibility of the proteins on the stem cell. Stem cell transfer is not a simple procedure and using stem cells does not mean that it will be accepted by any organism. Only immuno-compatible stem cells can be transferred to a person and the procedure is used where treatment is the goal.
As for your third part of question- I think you have mixed up procedures from different protocols with different end points. In therapeutic procedure you dont have to enucleate anything. Stem cells can be taken from body and separated out from other stuff like fat. Then the SCs are activated with stimulating factor and suspended in saline solution. This final solution is transferred to the patient body like blood transfusion.
Please note that SCs related procedures are many depending on the goal. The above is a general simplified procedure.