Stem cells?

Question

Could someone tell me where they come from? You hear a lot about stem cell research and extracting stem cells, but where do you extract them? Does it always involve the killing of an embryo or can u get the exact same thing from an umbilical cord?

Also, I am interested in arguments for and against.

Thanks =)

Answer 1

Stem cells are cells that retain the potential to differentiate into more than one mature cell type and have the capacity to self-renew (make more of themselves). There are many different kinds of stem cells. Pluripotent stem cells are capable of giving rise to any cell type, multipotent stem cells are limited to their specific tissue or a given lineage (neural stem cells, hematopoietic stem cells, mesenchymal stem cells, etc.). Totipotent stem cells can give rise to an entire organism. When people refer to stem cell research, most assume it is on pluripotent stem cells (i.e. embryonic stem cells). Embryonic stem cells are completely a laboratory artifact, they do not exist in normal organisms. Scientists derive pluripotent stem cells from the inner cell mass of a very early pre-implantation embryo, this does not hurt it and it could go on to give a complete organism. They culture these cells and select for ones that can be propagated indefinitely given the right conditions. It is these cells that are called embryonic stem cells (ES cells). Any normal cells from an organism will undergo senescence (stop dividing) after a set number of cell divisions and either die or sit around for a while but is completely and irreversibly out of the cell cycle (cannot divide again). Umbilical cord stem cells are multipotent, anyone who says they are pluripotent or ES-cell equivalent are not being truthful, they fail the most important test of pluripotent stem cells in that they cannot contribute in any substantial manner to all the lineages and cell types of an organism or integrate into the germ line. Mostly these are hematopoietic stem cells, and these only give rise to blood cells. The lady who did the lion's share of work on umbilical cord stem cells as "multipotent adult progenitors" (MAPs) that give rise to essentially all cell types and lineages was found to have been involved in major scientific misconduct and her work was never repeated in any other independent lab although many tried. If you want arguments for or against, you can find them on the NIH or NSF websites. At least those are based on science, logic, and even-tempers.

Answer 2

i think stem cells are cells that have no specific "job" i think they can be used to grow organs. im not positive

Answer 3

A stem cell is basically a "blank" cell that hasn't differentiated yet....meaning...it hasn't really been assigned a purpose, so we can create a purpose for it.

Stem cells are found on the umbilical cord, or can be extracted from an embryo.  You don't have to kill an embryo to remove stem cells.  This is a common misconception.  If you think of an embryo that is still in a small stage, maybe only a few dozen cells.  Those cells are just a blob...no bones, no organs, etc.  You can take out one or two cells, and it won't slow down the division of the other cells, or make the embryo develop slower....you are just brushing off a couple of blank cells.  Those "stem cells" can then be used to make stem cell colonies, and their removal didn't hurt the embryo in the least.

So in theory, anytime somebody wants to have a baby using artificial means....like invitro...before the embryo is placed in the woman's uterus, it would be possible to remove a cell or two, then place the embryos, and we'd have a big supply of stem cells each year, without having to harm any babies.

You can also create a pseudo stem cell by applying a super high electric charge to a cell, and blanking it...but it does retain its DNA, so some genentic material remains.

Stem cell research is a great thing that can help us solve diseases, injuries, etc.  What if somebody severed their spinal cord, but with stem cell treatment, we could get the stem cells to re-grow nerve tissue, and reverse paralysis?

Its really an interesting topic with tons of benefits.

Answer 4

Stem cells are undifferentiated cells that are found in any tissue of the body as well as in umbilical cord blood and embryo. Embryonic stem cells can differentiate to ANY cell type in body but the stem cells in the adult tissues can ONLY differentiate to the cells of the tissue that they come from. For example, the stem cells in your skin are responsible for replacing all the different type of cells that you can find in your skin. When you cut your finger, these cells become activated and produce all the cells necessary to repair your skin.

A more differentiable type of stem cells are taken from bone marrow. These stem cells can produce more different types of cells than stem cells of other tissues but they can not reproduce all types of cells like embryonic stem cells.

Embryonic stem cells are taken from the EXCESS embryos that fertility banks and clinics have and would destroy anyways. When a man and woman go to these clinics to get pregnant, many embryos are produced from their egg and sperm. A few of them will be implanted in the woman's womb and the rest are frozen to be used later in case non of the implanted embryos survive. Some time after a successful pregnancy and birth of a child, the frozen embryos will be destroyed. These are the embryos that can be used for stem cell research. The impression that an embryo will be killed to extract stem cells is not correct as these embryos would have been destroyed any ways.

Stem cells research promise a great future for many patients. In Europe scientists have been able to produce living and functioning bladders for kids who's bladders had to been removed for different reasons. Can you imagine what it means to kid to have his or her own bladder rather than having to carry a bag of urine with him/her?

Other organs will come soon after. And very soon paralyzed people will be able to walk and move again because of stem cell research. I think this is the least we can do for who put their lives in danger for us and get hurt in the line of duty.

I am a genetics student and if one day my knowledge and my research help one kid to be normal or help one person to walk again, I will be very proud.