Transcript Income Forecasts: 1998/99

Embryonic Stem Cells &
Cloning
Fiona Cunningham
Embryonic stem cells
• New hope for patients with Parkinson or
Alzheimer disease?
• Potentially - an unlimited source of cells,
tissues and organs for transplants and cell
therapy
What are embryonic stem cells?
• Derived from the inner cell
mass of a 1-week-old embryo
(blastocyst)
• Unlimited, prolonged selfrenewal
• Can divide and differentiate
into any type of body cell
Embryonic stem cells
• Can be driven down different differentiation
pathways in a controlled way in culture
• We don’t yet know the different signals that
control this
• Most research done to date has been on
mouse ES cells
• But mouse & human ES cells do not
respond in the same way
Uses of ES cell line
• Screening of drugs that may cause birth
defects
• Discovery & study of rare human proteins
• Study of early human development
• Gene therapy vector
• For transplantation of tissues
– still problem with rejection from patient
Overcoming rejection
• Banking of many ES cell lines representing
MHC alleles – will increase probability of finding a tissue
match
• Genetic modification of ES cell line so
‘immunologically naked’
Combining cloning & ES cell technologies
Cloning
• Cloning: producing a genetically identical
copy
• gene, cell, tissue, organism
• Reproductive cloning vs therapeutic cloning
• Nuclear transfer technology
• Dolly
Nuclear transfer
Human application
ES cell lines:
tissue for
transplantation
Why the controversy?
Deriving stem cells from
embryos destroys them!
In Australia
• Destructive embryo research is prohibited
in Vic and WA
• Human cloning is prohibited in Vic, WA, SA
(& possibly NSW)
In US
• Reproductive cloning has only recently
been prohibited (August 2001)
• Research using stem cells is permitted and
will now be govt as well as privately funded
• Private companies hope to ‘cash in’
– Geron Corporation + Roslin Bio-Med
– American Cell Technology (ACT)
Are there alternatives?
• Adult stem cells
• Human-animal chimera
• fusion of human DNA from a somatic cell with
enucleated animal eggs
• Change legislation
• exempt research on ES cell lines from bans on
embryo research (ES cells  embryos)
• De-differentiation of somatic
transform into ES cells??
cells
to
In the future ….
• Jenny (2 years old) has leukaemia.
• She needs a bone marrow transplant within 2
years.
• No donor found.
• We could clone Jenny - create an embryo
• then remove ES cells from the embryo
• to generate compatible bone marrow.
4. Fused cell develops to
blastocyst stage. New embryo
develops from inner cell mass
1. Healthy cell removed
from Jenny.
3. Jenny’s cell and
enucleated egg fused.
2. Nucleus removed
from donor egg.
6. Bone marrow
cells transplanted
into Jenny.
5. Cells removed from inner
cell mass. Directed to
develop into bone marrow
tissue
Should Jenny be cloned?
Consider this from the points of view of:
a) Jenny’s parents
b) Jenny’s doctor
c) Jenny herself
d) the cloned embryo
e) Jenny’s family minister
f) the Minister for Health (federal)
g) a ‘right-to-life’ activist
h) Jenny’s brother (5 years older)