STEM CELL ETHICS: THE NEGLECTED ISSUES. Dr. Christie Holland Rev. Dr. Karen Lebacqz

Transcription

1 STEM CELL ETHICS: THE NEGLECTED ISSUES Dr. Christie Holland Rev. Dr. Karen Lebacqz

2 Stem Cell Science -- some basic terms totipotent = able to make an entire organism. pluripotent = able to make all types of cells in the body (all three body layers). multipotent = able to make several types of cells, but not all types. Embryonic stem cells are pluripotent; adult stem cells are multipotent.

3 Stem cell science: Origin of stem cells 1. IVF-created blastocysts (+) Plentiful (-) Freezing damage -- low quality lines 2. Nuclear transfer blastocysts (SCNT) (+) Reduce rejection (patient s own cells) (-) Requires large numbers of eggs

4 Origin of stem cells cont. Umbilical cords/placentas (+) Easy to retrieve/bank (-) May not be pluripotent; may not contain enough stem cells Adult stem cells (includes newborns!) (+) No embryo destruction (-) Difficult to culture; limited potency Gene transfer? -- too new to predict

5 How are stem cells isolated? Embryo (fertilized/nuclear transfer)--> Blastocyst ( Hollow ball - c. 5 days)--> Take inner cell mass of stem cells--> Grow in culture; create stem cell line--> Differentiate into specific tissues (nerve, muscle, islet cells, etc.);

6 Clinical Trials: The New Frontier in science Cell lines: limited genetic diversity chromosomal changes due to aging created with old culture techniques (eg mouse feeder cells) contain animal products Tumorogenic potential Immune responses graft vs. host disease Methods to evaluate effectiveness of therapy

7 Moving from science to ethics Some neglected ethical and theological issues

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9 1. Justice Issues: The greatest good vs. the poor If justice requires wide access, then: We need new cell lines, as current lines will not assist all ancestral groups. How do we procure these? (Faden et.al.; also NRC/IOM Guidelines). How does the current market setting impact possible availability of therapies?

10 1a. New cell lines: Generation of new cell lines must be approved by ESCRO (Embryonic Stem Cell Research Oversight) committees. ESCRO committees must include community representatives and ethics experts -- here is a role for clergy or concerned lay people!

11 1b. New Cell Lines-- Creation of embryos for research Nuclear transfer or Therapeutic cloning But: it s not therapy and not cloning! Using embryos as means, not ends. Altered nuclear transfer (Hurlbut); Can ethical issues be avoided by use of amniotic fluid, cord blood, or other sources? -- Limitations...

12 1c. New cell lines: acquisition of tissue/eggs 1. Should donors be paid? Undue influence vs. Unfair advantage 2. Therapy-- first crack for donors? Therapeutic misconception vs. therapeutic hope 3. Recruitment: Advertising? [the UK furor] Vulnerable populations?

13 2. Moving to Clinical Trials: What prior research must be done? Adult stem cell work? Animal research? What level of purity of cells is required? Therapeutic vs. non-therapeutic trials? Unknown risks Modifications to phases of clinical trials? Premature therapy claims ( Medra ) recent statement from UK condemning claims of therapy

14 3. Impact on the future Quality of life vs. quantity of life Ethical issues in contributing to an already aging/graying society? International justice issues?

15 4a. Chimeras ( Mixing kinds ) Much current research = human ES cells into animals -- this creates a chimera. What is the moral status of chimeras? Do humans have a special dignity and is it threatened by creation of chimeras? What about animal dignity (Integrity of species)? Does it make sense to talk about species anymore?

16 4b. Chimeras: Xenotransplants etc. Religious prohibitions against the mixing of kinds But: xenotransplants are common today Specific issues: should chimeras be allowed to reproduce? Should implants into primate brains be prohibited?

17 5. Theological Grounding: God is still speaking! (Creation is ongoing; we are called to participate) We are created for salvation/wholeness (Genesis is not the final word!) We are created for justice and love Relationship is at the heart of being

18 Questions to ponder: What does it mean to be human? Or made in God s image? How much risk should people be allowed to take for themselves? How do we create justice in an unjust world? What is God still speaking about stem cells?...