UP #7: Human Embryonic Stem Cells
With selected student responses
QUESTION 1: Where do Human Embryonic Stem Cells (hES cells) come from? What are some of the ethical implications of using hES cells for medical research?
From LIL Q1 = hES cells are cells derived from the Inncer Cell Mass of a surplus embryos from the In Vitro Fertilization. That it is killing embryos that could become a full grown human being.
From LF Q1 = The hES cells come form the inner cell masses of human blastocysts, in vitro fertilized embryos less than a week old. The embryos from which the hES cells are derived from are extra embryos donated (with written consent) from patients who have gone through successful clinical procedures to treat infertility. Some of the ethical issues about using hES cells for medical research are that some believe that at the moment when an egg and sperm combine, that a life has been created. That to use hES cells from this life that has been created is to some considered murder of a human being. Once hES cells have been taken from the embryo, it can no longer become a human being.
From JR Q1 = They are cells derived from the inner cell mass of surplus embryos from IVF. If imaplanted into a woman's uterus, the cells may develop into a baby. Ethical issuse . . well using the cell of a potential baby to treat disease and help repair other tissues and such . . kind of taking the life of a child I would say.
From ASH: Q1 = Human Embryonic cells come from the Inner Cell Mass of surplus embryos from In Vitro fertilization. They can also come from developing germ cells in a 5-9 week fetus. Things that some fear may happen are: harvesting babies specifically for hes cells, money exchange for donation of embryos, or that donors might receive some benefits from commercial development. Basically, we are using cells from extra fetuses, and that will cause controversy.
From P: Q1 = hES cells come from early developed cells in the embryo. They are what forms the different tissues in our body...Some ethical implications of using them would include that of abortion. If there are genetic problems with the develeping embryo then the parent may be informed to determine it's destiny. This will most surely cause severe debate among prolife, prochoice individuals.
QUESTION 2: hES cells can form virtually every tissue in the body - skin, muscles, nervous system tissue, etc. How do you think scientists control the types of tissues that they are interested in using for research?
From RW Q2 = I am not sure how scientists control for this. i do not think i really understand this question either.
From Nick Q2 = They control what type of tissues are made by only giving the cells the required items for a certain tissue.
From BT Q2 = I have no idea. I would imagine that they can use any type they want. Maybe they can all the cells and then wait for them to specialize or perhaps they put them in with cells of that type and they automatically specialize to that type. I honestly don't know.
Response from Dr. Marrs: Scientists use different growth factors and hormones to 'turn on' the genes that will make the specific cell type needed.
QUESTION 3: hES cells are pleuripotent. What do you think this means? (Look in the web notes). What is NOT known is if human cells are totipotent. What do you think totipotent means and why do you think we do not know whether human cells are totipotent?
From Mo Q3 = That means that they can form any cell in the body, all three cell layers. I'm not sure what totipotent means, but it might be that any part of the body can be formed. Honestly, I have no idea.
From RV Q3 = Pleuripotent means that the cell can form virtually any cell in the body. Totipotent means that it is capable of developing into a complete organism or differentiating into any of its cells or tissues. We don't know if humans cells are capable of developing into a complete organism. They are able to specialize but don't know if they can form a complete organism.
From GS Q3 = They can form any cell in the body because they contain all three cellular layers. A totipotent cell is a cell that is capable of giving rise to all types of differentiated cell found in that organism. One single totipotent cell could, by cell division, reproduce the whole organism. Because when cells divide into different parts of the body they specialize in those parts making it hard for us to determine if they would produce different organisms.
From DJ Q3 = I think pleuripotent means that the hES cells are able to form virtually any cell in the body. Totipotent means capable of developing into a complete organism or differentiating into any of its cells or tissues. We probably do not know if human cells are totipotent because the only complete organism we know of is our human body.
From Dr. Marrs: Great answers - and we will NOT know whether human cells are totipotent until someone takes the step of cloning a human being. There is no reason to think they would not be, but the idea is strongly condemned by our government, scientists, and religious organizations.
QUESTION 4: [Totally optional] There are tremendous benefits to developing hES cells for treatment of diabetes, Alzheimers. etc. In your opinion, do these benefits justify their use in medical research, given that a human blastocyst must be used to obtain the cells?? Remember that only surplus embryos can be used to obtain hES cells. Embryos CANNOT be created for hES cells. (Your answers will be kept confidential!)
From Dr. Marrs: Thanks for all your thoughtful responses.