Stem Cell Research---Are You For or Against It? (page 3)

jschwehm

Hi:

I am for Adult Stem Cell Research and treating disease with those cells. Embryonic Stem Cell Research has many problems including severe ethical problems.

The following website has some interesting articles on the subject:

http://www.stemcellresearch.org/

Jeff S.

Double Edge

I'm for it (for the most part)....

article:

What are stem cells?

Stem cells are unspecialized cells that have two important characteristics that distinguish them from other cells in the body. First, they can replenish their numbers for long periods through cell division. Second, after receiving certain chemical signals, they can differentiate, or transform into specialized cells with specific functions, such as a heart cell or nerve cell.

Research is now being conducted on both adult and embryonic stem cells to determine the characteristics and potential of both to cure disease.

What are the sources of stem cells?

There are three sources of stem cells:

Embryonic stem cells (ESCs) are derived from 4- to 5-day-old embryos . At this stage, the embryos are spherical and are known as blastocysts. Each blastocyst consists of 50 to 150 cells and includes three structures: an outer layer of cells, a fluid-filled cavity, and a group of about 30 pluripotent cells at one end of the cavity. This latter group of cells, called the inner cell mass, form all the cells of the body.

ESC cultures are created in the laboratory by transferring the inner cell mass from a blastocyst into a specially treated plastic culture dish. The cells divide and, after several days, begin to crowd the culture dish. When this happens, the cells are removed and plated into several fresh culture dishes. This process is repeated many times, eventually yielding millions of ESCs. If, after six months, the cells keep dividing without differentiating, are still pluripotent, and are genetically normal, they are referred to as an ESC line.

The blastocysts used for creating ESC lines are derived from eggs that were fertilized in in vitro fertilization clinics but never implanted in a woman’s uterus. The resulting embryos were frozen and later donated for research purposes with the informed consent of the donors. Currently, there are over 400,000 unused frozen embryos in U.S. fertility clinics.

Because ESCs are pluripotent and relatively easy to grow in cell culture, they are attractive candidates for use in stem cell therapies. However, just injecting ESCs into a site of injury would probably result in a tumor growing in that spot. ESCs must first be directed to differentiate into the desired cells, such as heart muscle cells, blood cells, or nerve cells. To control ESC differentiation in cell cultures, scientists try different techniques, such as changing the chemical composition of the culture medium, altering the surface of the culture dish, or inserting specific genes into the cells.

One possible drawback to using differentiated ESC lines in stem cell therapies is that ESCs from one person might illicit an immune response when placed into another person, because the proteins on the ESC surfaces might be viewed as foreign by the recipient’s immune system. However, this is far from certain. ESC derivatives have been transplanted between species (for example, pigs to rats) without being rejected, so the possibility exists that ESC derivatives from one person might be safely transplanted into another person. Studies investigating this have yet to be done.
Adult stem cells are undifferentiated cells that are found in small numbers in most adult tissues. However, they are also found in children and can be extracted from umbilical cord blood. A more accurate phrase is “somatic stem cells,” although this phrase has yet to be generally adopted.

The primary roles of adult stem cells in the body are to maintain and repair the tissues in which they are found. They are usually thought of as multipotent cells, giving rise to a closely related family of cells within the tissue. An example is hematopoietic stem cells, which form all the various cells in the blood.

Recent evidence, however, indicates that some adult stem cell types may be pluripotent, or at least able to differentiate into multiple cell types. For example, hematopoietic stem cells can differentiate into neurons, glia, skeletal muscle cells, heart muscle cells, and liver cells. Whether they actually do this ordinarily within the body is unknown.

Blood from the placenta and umbilical cord that are left over after birth is a rich source of hematopoietic stem cells. These so-called umbilical cord stem cells have been shown to be able to differentiate into bone cells and neurons, as well as the cells lining the inside of blood vessels.

A potential advantage of using adult stem cells from a patient is that the patient’s own cells could be expanded in culture, treated to differentiate into the desired cells, and then reintroduced into the patient. The use of the patient’s own cells would eliminate any possibility that they might be rejected by the immune system. Disadvantages of using adult stem cells are that they are rare in mature tissues and it is more difficult to expand their numbers in cell culture, compared with ESCs
Embryonic (or fetal) germ cells are pluripotent stem cells derived from so-called primordial germ cells, which are the cells that give rise to the gametes (sperm and eggs) in adults. Scientists obtain primordial germ cells from the area in a 5- to 9-week-old embryo/fetus destined to become either the testicles or the ovaries (the dividing line between embryo and fetus is the end of the 8th week). Like ESCs, the primordial germ cells are transferred into a specially treated plastic culture dish, where they form germ cell colonies.
Less research has been performed using embryonic germ (EG) cells than ESCs, mostly because the embryos used for deriving EG cells are deliberately aborted, while the blastocysts used for deriving ESCs are produced through in vitro fertilization in a fertility clinic. EG cells are also difficult to maintain in cell culture because they have a tendency to differentiate spontaneously.

daniel-p

Which is more of an ethical problem: producing thousands of embryos at a fertility clinic, using one to impregnate a woman, and destroying the rest? or using those that were going to be destroyed to save exisitng lives?

I find it comical anyone could stand by an argument against stem cell research. But then again, religious conviction will always be at odds with the freedom pure science brings.

apfergus

I support all forms of stem cell research. Frankly I don't understand the ethical objections to embryonic stem cell research--which seems to be a byproduct of the opposition to abortion, another objection I don't understand. It's very common for a zygote to fail to attatch to the walls of the uterus and simply be flushed out with the next cycle. How is taking a 4-5 day embryo that would otherwise fail to develop or--in the case of elective abortion--be discarded (or develop into a miserable, neglected, unwanted child) wrong? It seems to be advantageous for multiple reasons.

crownboy

I'm for embryonic stem cell research, and especially for the one that the US Congress is advocating. The embryos that are going to be used are ones that would have been discarded and destroyed anyway, so if we're OK with that happening (for the purpose of helping people "create life"), why is this any different in this case (the goal of the research is to preserve and enhance life after all)?

And as others have already mentioned, we're talking about undifferentiated cells here, not actual people or near term fetuses, etc.

Kudra

OK I read a little on the issue and I think most people are ok with the embryonic stem cells (grown for 14 days) but the trouble starts when the researchers want to grow them longer to harvenst the cell types (liver, bone) that are hard for the undifferentiated cells to grow into. I think folks assume that you'll get runaway "fetus harvesting" and be farming out like, 5 month old fetuses...
I guess that the limitations of the 14 day embryonic stem cells necessitate a longer germination time?
-K

Midget-Sasquatch

I'm all for it. But like a couple of posters on here have also expressed, I think that all the unwanted zygotes and embryos slotted for destruction, should be used first, before creating other batches.

joe_black

From all the info I've read both pro and con, I believe the benefits are too overwhelming to be against it. Millions of lives can be saved, therefore I am supportive of of stem cell research.

rebel8

I am for it, but I'm not exactly a neutral party. I expect to be treated and cured by stem cells within the next decade.

daniel-p

Bush just vetoed the bill - of course. He made it an issue of pro-life, which it is not. One of his closing statements: "American taxpayers would, for the first time in our history, be compelled to fund the deliberate destruction of human embryos. I'm not going to allow it."

As a side note: in 2003, US subsidy payments to tobacco farmers amounted to $328,000,000. So American taxpayers are compelled instead to fund the destruction of full-grown humans.

Stem Cell Research---Are You For or Against It?

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