Transcript Moral Issues of our Day

Cloning & Stem Cells
Dr. Heinz Lycklama
[email protected]
www.osta.com/messages
@ Dr. Heinz Lycklama
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Stem Cells and Cloning
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The Human Cell, DNA, Nucleus, Chromosomes
Early Stages of Embryo Development
Stem Cells – Embryo & Adult
The Cloning of Dolly
Cells, DNA, Chromosomes, Telomeres
Cloning of Humans?
Comparison of stem cells and cloning techniques
Medical & Ethical Challenges
History & Summary
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The Human Cell
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Cell size – 10 micron in diameter
220 types of human cells – blood, bone, skin, heart, etc.
From conception to birth, baby adds
15,000 cells per minute
~50 trillion cells in human body
Each cell more complex than space shuttle
DNA (chromosomes) are most complex
molecules in universe
All chromosomes from one person would
stretch from earth to moon and back 5,000,000 times
Information in chromosomes would fill books that would fill
Grand Canyon 40 times
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The
Human
Cell
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The Cell Nucleus
The nucleus is a highly specialized
organelle that serves as the information
and administrative center of the cell. This
organelle has two major functions. It
stores the cell's hereditary material, or
DNA, and it coordinates the cell's
activities, which include intermediary
metabolism, growth, protein synthesis, and
reproduction (cell division).
DNA molecule – double-helix, two
strings twisted together in a long spiral
Packed inside the nucleus of every
human cell is nearly 6 feet of DNA,
which is divided into 46 individual
molecules, one for each chromosome
and each about 1.5 inches long.
http://www.cartage.org.lb/en/themes/Sciences/Zoology/AnimalPhysiology/Anatomy/AnimalCellStructure/Nucleus/cellnucleus.jpg
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Early Stage of Embryo Development
•Egg + sperm = 1st cell
•2 genetically identical
cells within 12-15 hours
•8 cell stage in 2 days
•Blastocyst in 4-5 days
•Chemical exchange
occurs between blastocyst
and mother’s tissue
http://departments.weber.edu/chfam/Prenatal/blastocyst.html
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Stem Cells – What Are They?
A stem cell is essentially the building block
of the human body. The stem cells inside an
embryo will eventually give rise to every cell,
organ and tissue in the fetus's body.
Unlike a regular cell, which can only replicate
to create more of its own kind of cell, a stem
cell is pluripotent. When it divides, it can
make any one of the 220 different cells in the
human body.
Stem cells are pluripotent, which means that
they can develop into every cell, every tissue
and every organ in the human body.
Stem cells also have the capability to selfrenew -- they can reproduce themselves
many times over.
http://science.howstuffworks.com/cellular-microscopic-biology/stem-cell.htm
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Embryonic Stem Cells
1. They can generate large
quantities of tissue rapidly
Human Embryonic Stem Cells
2. They can become any cell in the body
Embryonic stem
cells
Brain
Heart
Fat
Bone marrow
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Cartilage
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More on Stem Cells
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Stem cells are capable of self-renewal and
becoming many different cell types (e.g. blood,
nerve, bone, etc.) to form tissue in humans
Two types of stem cells
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Embryonic stem cells (ESC)
Adult stem cells (ASC)
Each individual begins as a single cell or zygote
but as the embryo grows, different cells in
different places have to specialize, so that only
certain instructions are executed—the cells
become differentiated. The instructions are there,
but turned off somehow
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Stem Cells – How They Work
There are two types of stem cells: embryonic stem
cells and adult stem cells. Embryonic stem cells
come from an embryo -- the mass of cells in the
earliest stage of human development that, if
implanted in a woman's womb, will eventually grow
into a fetus. When the embryo is between three and
five days old, it contains stem cells, which are busily
working to create the various organs and tissues that
will make up the fetus.
Adults also have stem cells in the heart, brain, bone
marrow, lungs and other organs. They are our builtin repair kits, regenerating cells damaged by disease,
injury and everyday wear and tear. Adult stem cells
were once believed to be more limited than stem
cells, only giving rise to the same type of tissue from
which they originated. But new research suggests
that adult stem cells may have the potential to
generate other types of cells, as well.
http://science.howstuffworks.com/cellular-microscopic-biology/stem-cell.htm
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How Cloning Works
Cloning is the process of making a
genetically identical organism through
nonsexual means. It has been used for many
years to produce plants. Animal cloning has
been the subject of scientific experiments for
years, but garnered little attention until the
birth of the first cloned mammal in 1997, a
sheep named Dolly.
Sexual reproduction involves the merging of
two sets of DNA (one from the father's sperm
and one from the mother's egg) to produce a
new offspring that is genetically different
from either parent.
Asexual reproduction (without sex)
produces offspring that are genetically
identical to the single parent organism.
Since Dolly, several scientists have cloned other
animals, including cows and mice. The recent
success in cloning animals has sparked fierce
debates among scientists, politicians and the
general public about the use and morality of
cloning plants, animals and possibly humans.
http://science.howstuffworks.com/genetic-science/cloning.htm
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Dolly – The First Cloned Mammal
In 1997, cloning was revolutionized when Ian Wilmut
and his colleagues at the Roslin Institute in Edinburgh,
Scotland, successfully cloned a sheep named Dolly.
Dolly was the first cloned mammal.
Wilmut and his colleagues transplanted a nucleus from a
mammary gland cell of a Finn Dorsett sheep into the
enucleated egg of a Scottish blackface ewe. The
nucleus-egg combination was stimulated with
electricity to fuse the two and to stimulate cell division.
The new cell divided and was placed in the uterus of a
blackface ewe to develop. Dolly was born months later.
Dolly was shown to be genetically identical to the Finn
Dorsett mammary cells and not to the blackface ewe,
which clearly demonstrated that she was a successful
clone (it took 276 attempts before the experiment was
successful).
http://science.howstuffworks.com/genetic-science/cloning3.htm
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Cloning, Cells, Chromosomes
Chromosome
Cell Nucleus
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Chromosomes and Telomeres
Telomeres
Gene 1
TTAGGG
Gene 2
Chromosome
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DNA
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Telomere
Length in
Base Pairs
Declines
With Age
(human
white blood
cells)
8,000
3,000
1,500
0 35 65
Age (years)
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The Cloning of Dolly
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Cloned from a healthy 6 year-old sheep
Used 277 cloned embryos to produce one
cloned sheep
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Failed 276 times
Took 277 attempts to clone Dolly
Showed signs of premature aging at age 3
Died at age 6 (average life = 13) from
progressive lung disease (old age)
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DNA was already 6 years old when born
Telomere length declines with age *
* Can be increased by telomerase enzyme
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Technology
of cloning
Human Cloning?
If human reproductive cloning proceeds, the
primary method scientists will likely use is
somatic cell nuclear transfer (SCNT), which is
the same procedure that was used to create Dolly
the sheep. Somatic cell nuclear transfer begins
when doctors take the egg from a female donor
and remove its nucleus, creating an enucleated
egg. A cell, which contains DNA, is taken from
the person who is being cloned. Then the
enucleated egg is fused together with the cloning
subject's cell using electricity. This creates an
embryo, which is implanted into a surrogate
mother through in vitro fertilization.
If the procedure is successful, then the surrogate
mother will give birth to a baby that's a clone of
the cloning subject at the end of a normal
gestation period.
http://science.howstuffworks.com/genetic-science/human-cloning1.htm
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Types of Cloning
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Reproductive – scientists transfer genetic material from the
nucleus of a donor adult cell to an egg whose nucleus, and thus its
genetic material, has been removed. The reconstructed egg
containing the DNA from a donor cell must be treated with
chemicals or electric current in order to stimulate cell division.
Once the cloned embryo reaches a suitable stage, it is transferred to
the uterus of a female host where it continues to develop until birth
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Therapeutic – the production of human embryos for use in
research. The goal of this process is not to create cloned human
beings, but rather to harvest stem cells that can be used to study
human development and to treat disease.
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To produce stem cells for research or treatment
Recombinant DNA – also called genetic engineering
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To correct a defect/disease in a person
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Recombinant DNA Cloning
Recombinant DNA – Hybrid DNA
produced in the lab by joining pieces of
DNA from different sources.
To splice a human gene (in this case, the
one for insulin) into a plasmid, scientists
take the plasmid out of an E. coli
bacterium, cut the plasmid with a
restriction enzyme, and splice in insulinmaking human DNA. The resulting hybrid
plasmid can be inserted into another E.
coli bacterium, where it multiplies along
with the bacterium. There, it can produce
large quantities of insulin.
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Recombinant DNA Cloning
The production of a recombined
bacterium using a gene from a
foreign donor and the synthesis of
protein encoded by the
recombinant DNA molecule.
The genes used in DNA
technology are commonly
obtained from host cells or
organisms called gene libraries.
A gene library is a collection of
cells identified as harboring a
specific gene. For example, E.
coli cells can be stored with the
genes for human insulin in their
chromosomes.
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The Goal of Stem Cell Research
The goal of any stem cell therapy is
to repair a damaged tissue that can't
heal itself.
This might be accomplished by
transplanting stem cells into the
damaged area and directing them to
grow new, healthy tissue.
It may also be possible to coax
stem cells already in the body to
work overtime and produce new
tissue.
To date, researchers have found
more success with the first method,
stem cell transplants.
http://learn.genetics.utah.edu/content/tech/stemcells/scresearch/
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Creating Stem Cells for Research
http://learn.genetics.utah.edu/content/tech/stemcells/sccreate/
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Getting ESC’s Using Reproduction
http://www.crystalinks.com/stemcellmap.jpg
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“Consensus” View of Stem Cells
http://dels.nas.edu/bls/stemcells/images/comparison_types_of_stem_cells.jpg
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Known ESC Problems/Concerns
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Require lifelong use of drugs to prevent
rejection of tissue
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Can produce tumors from rapid growth when
injected into adult patients
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Can produce tragic side effects (New England
Journal of Medicine)
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Mice clones using ESC were genetically
defective
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Most clonings do not produce viable offspring
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Most clones have serious defects and die early
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Conclusions – ASC/ESC Research
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Adult Stem Cell research/therapy
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Does not destroy life
Able to produce differentiated stem cells
Successfully treated 70+ conditions
Embryonic Stem Cell research/therapy
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Destroys original embryos (life)
Not successful in treating any condition
Many side effects
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Medical/Ethical Issues
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Embryonic stems cells can be developed from
discarded fertilized eggs in fertility clinics,
aborted or miscarried fetuses. Whenever a human
fetus is cultivated in the laboratory to develop into
stem cells, it is no longer viable as a human fetus.
In other words, the embryo is destroyed.
While a majority of Americans supports stem cell
research, a majority of them oppose it if they
know that it involves embryo destruction.
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Ethical Challenges
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There are web sites offering human
sex cells for sale.
Sperms of Nobel laureates and eggs
of beautiful models or female
students of prestigious institutions
of higher learning are collected and
sold to the highest bidders
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Special Egg Donor Needed
• Preferred donor will
meet the following
criteria:
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Height 5’-6” or taller
Caucasian
High ACT or SAT score
College student or
graduate under 30
– No genetic medical issues
– Extra compensation for
gifted athlete,
science/math student or
musician
$80,000
Stem Cell & Cloning Risks
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David Prentice, Ph.D. Genetics:
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Cloning Expert Dr. Dixon states:
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“Adult stem-cell research … has already shown
itself to be extremely promising for treating numerous
degenerative diseases such as heart disease, stroke,
Parkinson’s, Alzheimer’s, and diabetes.
“The greatest worry many scientists have is that
human clones - even if they don’t have monstrous
abnormalities in the womb - will need hip
replacements in their teenage years and perhaps
develop senile dementia by their twentieth birthday
The media has distorted the truth
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Summary
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Some stem cell history
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Michael Fox & Parkinson disease
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Breakthrough with ASC in 2009
Touts ESC research but treated using ASC
Many ASC success stories
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Spinal operation
Stems cells from own hip to repair heart
Stem cells from own bone marrow injected in
coronary arteries result in increased function
Stem cells from good eye to repair bad one
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