Earth Science: Human – Gene Technology – Stem cell Research
Stem cells are undifferentiated body cells; they do not belong to cells of a definite cell type in an organism. They are divided into adult or somatic stem cells (originating from a fetus or adult) and embryonic stem cells.
Adult stem cells are responsible for producing replacement cells for renewing certain tissues. For example bone marrow stem cells can continuously restore blood components, while others can renew muscle or nerve cells. Adults have about 20 different kinds of stem cells.
Researchers hope to be able to apply this cell replacement ability to the therapeutic treatment of organ damage by taking a sample of a patients stem cells, allowing them to differentiate into specialized types in the lab, and reimplanting them into the body.
Although adult stem cells have a much lower development potential than that of embryonic stem cells, their removal directly from the body, for example by biopsy, is not controversial and therefore most development and funding is directed into this branch of human stem cell research. Embryonic stem cells Embryonic stem cells are formed during the early phase of embryonic development.
Cells of this type are able to divide infinitely. Theoretically they can develop into cells to fit any of the approximately 210 types of tissue found in the human body. This ability is called pluripotentiality. The possibility of producing embryonic stem cells, which can be multiplied in vitro almost infinitely, opens new doors for developmental research, especially in medicine.
In the future it may be possible to treat a heart attack victim by removing DNA from the patients body cell and transferring it into an egg cell without a nucleus. An embryo blastocyst, carrying the genetic information of the patient, could be grown in vitro. Embryonic stem cells could then be removed and treated in a way that would result in the development of heart muscle tissue, which could be used to replace damaged tissue.
Rejection by the body would be unlikely as, after all, it consists of the bodies own tissue. One day such therapeutic cloning could theoretically cure numerous diseases. However, this area of stem cell research is still very controversial.
ETHICAL DISPUTE
Some people are opposed to embryonic stem cell research, because although the embryos are at an extremely immature stage (an assemblage of cells called a blastocyst), they are destroyed during the stem-cell production process.
At the center of this ethical discussion is the question of when an embryo begins to be a human being and should therefore be protected by human rights. Meanwhile researchers have been able to reprogram human skin cells so that their properties are almost equivalent to that of embryonic stem cells.
This may offer a solution and render the discussion about ethical values irrelevant.
BASICS
RESEARCH RESTRIC TIONS In some countries, for exam pie, Germany and Ireland, it is illegal to use human embryos for stem cell production.
Others allow their use but impose varying restrictions and conditions.