Transcript Building New Bones with Stem Cells

Stem Cells, Cloning, Genetically
Modified Organisms and Gene
Therapy…
Stem Cells
The promise and the
protest
Documentary: Leslie
MacKinnon
Online: Owen Wood
June 5, 2001
Thirty-eight-year-old Marc Bergeron was diagnosed
with Parkinson's Disease four years ago. The
disease, which usually strikes people over 60, is
slowly taking control of his body.
Currently, there is no way to predict who the disease
will hit, there is no way to prevent it, and there is no
cure.
But all that could change.
Scientists have found something they believe could
revolutionize medicine by giving them the power to
repair tissue damaged by disease or injury.
"Stem cells… are going to usher in a new phase in medical
research and treatment," says Roger Gosden, a research
scientist at the Royal Victoria Hospital in Montreal.
They're called stem cells. Essentially, stem cells are cells
that haven't matured. This means they are just waiting to
become any type of cell in the body – skin, bone, brain
tissue.
The promise of stem cells is that if doctors can harvest
enough of them, they could grow new skin for burn victims
or treat neurological diseases or repair spinal injuries or do
a whole bunch of things that are only a dream today. The
possibilities seem endless.
But there's a catch.
What are stem cells?
• Cells that can differentiate (evolve) into many
different types of cells
• Some stem cells are totipotent: can transform into
many different types of cells
How can we use stem cells?
• To repair damaged tissue,
ex. Neural injury
• Instead of transplants
Where are stem cells present?
• …in the bone marrow of adults
• …in the adult brain
• …the catch: in embryo tissue
WORKER CELL: An adult stem cell,
collected from human bone marrow. It
can replace blood cells killed by cancer
or by cancer treatments like radiation
and chemotherapy.
To produce large numbers of stem
cells…
• It is necessary to clone embryos
• Stem cells are collected when embryo is 5
days old and contains nearly 150 cells
• The rest of the embryo is DESTROYED!!
(The ethical dilemma!!!)
Cloning Embryonic Stem Cells
• Nucleus from an adult body cell is
transferred into an empty unfertilised egg
cell.
• The embryo grows and the stem cells are
taken and induced to differentiate into the
cells that are needs (ie: insulin producing
cells, muscle cells, cardiac cells).
How can we avoid dealing with
embryonic stem cells but still use
stem cells?
• Harvest from adults
• Grow in Petri plates
• Use for therapy not
for cloning people!!!
Induced pluripotent stem cells…
a new hope???
• Scientists have recently made a break through in
stimulating adult mouse cells to revert back into
pluripotent cells (Cells that have the ability to give
rise to any type of cell in an organisms body.).
• Scientists in Japan have introduced genes into
adult cells that are normally only active in
embryos. The result was that these cells were
`reprogrammed` into pluripotent cells.
Therapeutic cloning
• Used to produce
tissue that is identical
to the donor, to
prevent rejection
Reproductive Cloning
• Creates an organism with the same
genetic material (DNA) as the
original organism – an EXACT
COPY of the donor
Dolly the Sheep
• The first cloned sheep
Cloning Genetically Modified
Organisms
• Biotechnology has given scientists the
ability to alter the genetic material in an
organism.
• Genetically modified organisms can carry
genes from other species.
• IE: Insulin is produced by bacteria and yeast
that have been genetically modified to
contain copies of the human gene that codes
for insulin.
• Scientists at the
University of Calgary
recently inserted the
human insulin gene into
a safflower plant.
• It is a very cost effective
way to mass produce
insulin.
• The entire world’s
supply of insulin could
be produced on 65
square km of prairie
farmland.
Gene therapy
The desired gene is
inserted into a cells
nucleus using a
retrovirus as a carrier
The defective gene is
replaced by functional
gene
Gene Therapy … use to correct
defective genes??
• Successes:
– Restoring vision in patients with inherited
retinal disease
– Repairing the gene responsible for Duchenne
Muscular Dystrophy
– Restore hearing in Guinea Pigs
– Video…
Plenary
• 1. What are stem cells?
• 2. What is the difference between therapeutic
cloning and reproductive cloning?
• 3. In the video clip at the beginning of class, what
type of cloning were scientists interested in?
• 4. What are genetically modified organisms and
how are they being used today?
• 5. What is gene therapy and what are some
success associated with it?
• 6. What is the big deal with cloning embryos?
Why are some people up in arms about it?