Lecture 15

Stem Cell Research Sources of Stem Cells [figure 13.2] ? ? Embryonic Stem Cells o leftover embryos from in vitro fertilization (IVF) attempts ? usually a 3-5 day old blastocyst ? couple must give consent to donate to science ? generally asked before IVF begins and again when finished with pregnancy attempts ? could also be donated to other couples ? otherwise embryos will remain stored indefinitely or will be destroyed o embryos created for this purpose ? mix egg & sperm ? sperm easily obtainable ? eggs must be induced, harvested ? hormone shots to induce superovulation ? surgical harvesting ? some risk to donor o either way, requires destruction of embryo ? is this destroying a human life? ? is it OK if it was going to happen anyway? ? is it worse if we create an embryo just to destroy it? o might, in future, be possible to extract some stem cells without destroying embryo ? is this better? ? does it mean we must implant (can't destroy) rest of embryo? ? are we destroying the twin to the embryo? ? Fetal Germ Line Stem Cells o from aborted fetuses ? can be from spontaneous abortions (miscarriages) ? are these cells chromosomally abnormal? ? when do they happen? (after 8 weeks?) ? can be from induced abortions ? timing & health of cells likely to be more optimal o germ line cells should be least determined, most pluripotent of fetal cells ? Umbilical Cord/Placenta Stem Cells o generally for blood stem cells o are pluripotent, not totipotent ? Adult Stem Cells (Somatic Stem Cells) o stem cells are found in some adult tissues ? brain, intestine, muscle, skin blood o are a small fraction of cells in those tissues ? ultimate source of new cells o are pluripotent, not totipotent ? under right conditions can be induced into other cell types o still must get consent of patient ? Via Non-Reproductive Cloning o reverse inactivation of developmental genes o transfer somatic nucleus to enucleated egg o now have totipotent cell ? could be induced to develop into particular tissue ? is this now (at least transitionally) a person? ? does it open the door to reproductive cloning? Uses for Stem Cells ? Repair or replacement of damaged tissue o heart disease & stroke- heart tissue o Parkinson's, Alzheimer's- brain tissue o replacement cells for those who've undergone radiation treatment for cancer o skin tissue for burn victims o whole new organs? Stem Cell Laws ? Federal funds cannot be used for research which involves destroying embryos, nor for research involving human cloning ? Federal funds can be used to study embryonic stem cell lines provided: o removal of cells from the embryo must have been initiated before August 9, 2001 (when President Bush announced this policy) o the embryo from which the stem cell line was derived must no longer have the possibility of developing further as a human being o the embryo must have been created for reproductive purposes but no longer be needed for them o informed consent must have been obtained from the parent(s) for the donation of the embryo o no financial inducements for donation are allowed ? There are 22 cell lines which meet these criteria ? States and private foundations are free to fund such research o California, Illinois, Ohio, Connecticut, Massachusetts and New Jersey have passed, or are considering passing, appropriations to fund embryonic stem cell research o Virginia and Indiana have created funds/research centers to support adult stem cell research, but have thusfar not appropriated monies ? States are free to pass laws banning this research, however funded o South Dakota strictly forbids research on embryos regardless of the source o Louisiana specifically prohibits research on in vitro fertilized (IVF) embryos o Illinois and Michigan prohibit research on live embryos o Arkansas, Indiana, Iowa, Michigan, North Dakota and South Dakota prohibit research on cloned embryos o Missouri forbids the use of state funds for reproductive cloning but not for cloning for the purpose of stem cell research o Arizona prohibits the use of public monies for reproductive or therapeutic cloning o Nebraska limits the use of state funds for embryonic stem cell research. Restrictions only apply to state healthcare cash funds provided by tobacco settlement dollars ? State by state regulations at http://www.ncsl.org/programs/health/genetics/embfet.htm Issues ? Source of Stem Cells o personhood of an embryo ? detroying some to help others? o complicity with evil? ? compare organ donation from a murder victim to stem cell research using embryonic tissue o degree of separation between source and use ? stem cell researcher who offers to perform abortions (perhaps at lower cost?) to obtain source material ? urging women to make abortion decision quickly, so tissue can be used in research ? increasing the likelihood or diluting the "badness" of abortion by allowing some "good" to come out of it ? should the "termination" conversation be entirely separate from "donation" conversation? o should we put off most promising areas of research today (embryonic stem cells) in hopes we will learn enough later on to use less ethically-conflicted sources (adult stem cells)? ? How to handle patchwork quilt of laws