Stem Cells andEmbryonic

Development

How old is this?What is it?

What is this?How old is it?

© Mark Hill, UNSW

Central ethical question surrounding embryonic stem cell

research:

Under what circumstances, if any, can 5-14 day old human embryos be:

1. Created and destroyed (prevented from developing further, then immortalized) for research purposes?

2. Donated as research material as a result of the In Vitro Fertilization procedure?

3. Checked and screened for certain genes then selected for or against?

Outline of Presentation

• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?

Natural Fertilization

The “Old Fashioned Way”

+ =

Outline of Presentation

• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?

In the IVF procedure, sperm and eggs “interact” in a dish leading to insemination.They literally swim up to the egg and burrow toward the nucleus.The first one to get there wins, and all others are blocked out.

Male fertility issue: Sometimes sperm cannot latch onto and penetrate the egg. They may choose to have Intra(within)-Cytoplasmic Sperm Injection (ICSI)

Day 1

EmbryonicStemCells

Outline of Presentation

• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?

Embryonic Development: Fish model

Keller et al. 2008

At what point is it a fetus? • Days 7-14: Uterine implantation• Day 14: Three distinct layers begin to form (no

more pluripotent stem cells)• Days 14-21: Beginning of future nervous system• Days 21-24: Beginning of future face, neck,

mouth, and nose• Weeks 3-8: Beginning of organ formation

This picture is Week 5

• Week 5-8+: Now it’s called a fetus (no consensus on a single timepoint)

Outline of Presentation

• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?

This cellCan form the

entire human being

This cellCannot form the

entire human being

Fully mature

Symmetric cell division

Asymmetric cell division

1. Self-renews 2. Differentiates

Progenitor cell

Stem cell Stem cell

Outline of Presentation

• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?

What is stem cell research?

• Understand more about development, aging, disease– Experimental model systems

• Prevent or treat diseases and injuries– Cell-based therapies– Pharmaceutical development

• Includes testing and drug delivery

Spinal cord injury:Example of embryonic stem cell-based therapy

Geron video: http://www.geron.com/grnopc1clearance/

CIRM funding breakdown: Cell Type

CIRM funds many types of Stem Cell Research

Outline of Presentation

• Natural Fertilization • In vitro fertilization• Embryonic development• Where are embryonic stem cells found?• What are the other types of stem cells?• How do CIRM scientists use embryonic SCs?• Can and should we select for genetic makeup?

Pre-implantation Genetic Diagnosis• A procedure to see if the baby has a chance of

inheriting genetic diseases• One-two test cells taken from morula stage• The embryo can grow normally if chosen for

implantation• Two techniques:

– Heteroduplex Analysis: DNA is tested for structural abnormalities

– Fluorescence In Situ Hybridization (FISH): Chromosomes are dyed to look for translocations and check the number of chromosomes

Ethics of Pre-implantation Genetic Diagnosis

• If the embryo shows a genetic variation linked with a genetic disease the parents could decide to terminate that pregnancy or not use that embryo

Discuss:

Under what circumstances, if any, can 5-14 day old human embryos be:

1.Created and destroyed (prevented from developing further, then immortalized) for research purposes?

2.Donated as research material as a result of the In Vitro Fertilization procedure?

3.Checked and screened for certain genes then selected for or against?