GROUP 4 PROJECT- STEM CELL
RESEARCH
By: Jeet Mehta, Chelsea Bodoe, Jayneel
Limbachia and Davina Sran.
WHAT ARE STEM CELLS?
Stem cells are basically cells found in every
multi-cellular organism.
 The difference between them and other cells is
their ability to renew themselves.
 While renewing, they can differentiate (specialize
or transform) into many different cell types.
 Stem-cell research started during the early
1960’s.

SCIENTIFIC DEFINITION
Stem cells are mainly defined by 2 important
properties:
1.
Self-Renewal: It is their ability to complete
many cell division cycles while maintaining the
same state.
2.
Potency: It is their capacity to specialize into
many different cell types. Potency describes the
cell’s potential to differentiate into different cell
types (differentiation potential).
SELF-RENEWAL
Self-Renewal also has two main mechanisms, and
these exist so the cell’s population can maintain a
certain state.
1.
Obligatory Asymmetric Replication:
The stem cell divides into 1 identical daughter cell
and 1 differentiated (transformed) daughter
cell.
2. Stochastic Differentiation:
One Stem cell divides into 2 transformed daughter
cells and another stem cell divides into 2
identical daughter cells.
POTENCY
As mentioned earlier, potency of a cell describes its
potential to specialize or differentiate.
There are 5 types of cell potency:
1.
Totipotent:

Totipotent cells can differentiate into
embryonic and extra- embryonic (located
outside the embryonic body) cell types

They can construct a complete functioning
organism.

Produced from the fusion of a egg and sperm
cell

Totipotent cells can also be produced from the
early divisions of a fertilized egg.
POTENCY CONT…
2. Pluripotent:
 Pluripotent stem cells come from totipotent cells.
 They can differentiate into almost all cell types.
 They can create fetal and adult cells but cannot
develop into the fetus or animal itself because
they do not contribute towards non-embryonic
tissue.
 Pluripotent cells can also be forcefully create
from non-pluripotent cells, usually somatic cells.
POTENCY CONT…
3. Multi-Potent:
 Multi-potent stem cells can transform into many
different cells, as long as they are in the same
“family” of cells (originate from the same organ)
4. Oligopotent:
 Oligiopotent cells can specialize into only a few
cells
5. Unipotent:
 Unipotent stem cells can only produce their own
cell types
 The only difference between them and normal
cells is their ability of self-renewal.
PRACTICAL DEFINITION
The definition of stem cells practially is this:
Stem Cells – a cell that can regenerate tissue and
sustain it over a lifetime.
This definition can be applied in many medical
uses of stem cells such as bone-marrow
operations, hematopoietic cells etc.
There are two main types of stem cells:
1. Embryonic
2. Adult (Somatic)
EMBRYONIC STEM CELLS
Embryonic stem cells are pluripotent cells
 They are found in the inner cell mass of the
blastocyst (structures inside an early stage
embryo)
 Embryo’s reach blastyocst stage 4-5 days after
egg fertilization
 The problem with embryonic stem cells is that
isolating the inner cell mass to obtain these cells
kills the embryo, thus creating many ethical
issues.

WHERE DO THEY COME FROM?
Formation of Embryonic Stem Cells and the types of organs they can
HUMAN EMBRYONIC STEM CELLS
ADULT STEM CELLS (SOMATIC CELLS)
They are Undifferentiated cells (cells that have
not changed)
 Found throughout the body after the embryo is
developed
 Somatic stem cells multiply through cell division
 They are used to replenish or revive dying cells
and tissues.

SOMATIC CELLS CONT…
They can be found in both juvenile and adult
humans and animals.
 The main property of somatic cells is that they
can divide indefinitely and create cells of all
types from the organ of their origin, possibly
creating the whole organ.
 They are not controversial because instead of
deriving them from a dead embryo, they are
found in normal adult muscle tissue.

HUMAN SOMATIC STEM CELLS
USES OF STEM CELLS
WHY IS STEM
CELL RESEARCH
DONE?
STEM CELLS

Stem cells can be made into any kind of cell,
therefore, they are manipulated to do the job
that another group of cells may lack
CANCER
Cancer is an
example of
manipulated stem
cells
 Stem cells leads to
cancer as they are
mutated
 Normal mature cells
do their assigned
job

TO
SUM UP…
Research is done to visualize how to
create these other wanted cells
OTHER
POTENTIAL USES
Research also leads to other potentials such
as:
 human cloning or
 whether these embryos are human life

CONTROVERSY
 Research
is the primary reason for
controversy
 Human cloning is a part of research
and leads to many ethical arguments
 Many humans argue that it not within
a man’s preview to manufacture,
manipulate or destroy human life
HOWEVER…
Research is needed to carry out the methods
to create these other cells
 Proper procedure and precautions must be
taken

METHODS OF
EXTRACTING
STEM CELLS
USES FOR THE BODY

Sometimes useful in helping body replenish itself
& repair disease


Ex. Heart failure
Process of removal/re-admittance:
Patient's stem cells extracted from the blood
 cultivated in a lab within 5 days into several tens of
millions of synergetic cells of the patient,
 then injected into the patient

USES FOR THE BODY CONT’D

Stem cells widely known for role in in-vitro
fertilization


extracted from ovaries
Stem cells can also be conceived as unborn fetus
Hence reason research is a major ethical issue in
society
 Are humans really killing fetuses, even if they are
undeveloped?

AMNIOTIC STEM CELLS


amniotic sac fills with water after fertilization
 ‘liquid’ contains proteins, carbohydrates, lipids
and phospholipids, urea and electrolytes, all of
which aid in the growth of the fetus
Amniocentesis = process to remove amniotic stem
cells to check on fetus
AMNIOCENTESIS
Regular procedure
 Many amniotic stem cells can be removed
without harming the fetus

 Therefore,

not as much controversy!
Process:
 Needle
 then
first inserted through mother's abdominal wall
through wall of the uterus, & finally into amniotic sac.
ADVANTAGES/DIS
ADVANTAGES OF
STEM CELLS
ADVANTAGES OF STEM CELLS


Form cells and tissues for medical therapies.
Treat diseases as replacement cells.


Potentially reduce the illness and mortality for those
awaiting transplant.
Diseases that could be cured by stem cells:





Cardiovascular diseases
Burn victims
Type I diabetes
Parkinson’s disease
Arthritis
ADVANTAGES (CONT’D)


A renewable source of replacement cells is
possible if the stem cells are differentiated into
specialized cell types.
The ability to reverse diseases
Ex: Replaced healthy new muscle cells for a patient
suffering from heart attack.
 New brain cells for damaged brain cells as a result of
Parkinson’s disease.
 treat genetic defects by introducing normal healthy
cells that do not have the defects.


Burn victims’ suffering can be put to an end by
creating new and healthy tissues from stem cells.
ADVANTAGES (CONT’D)

Stem cells are used to create specialized blood
cells for bone-marrow transplants.


They are removed from a tissue and then are differentiated
outside the body before transplanting them back into the
patient to replace damaged tissues.
usage in pharmacy:
Stem cells can be used as testing grounds for new
drugs, avoiding animal and human testing.
 ex: to test an anti-tumour drug, a cancer cell line
could be created.

ADVANTAGES (CONT’D)

Organ donating problem can be avoided by
extracting stem cells from a cloned embryo
and use it to grow organs.


Results in a much lesser chance of tissue rejection as well.
Regarding the ethical implications of stem
cells; it is important to mention that embryos
are leftover from intro fertilisation and would
be other wise be destroyed

Thus, a better use fo the embryos includes
advancing human health.
DISADVANTAGES OF STEM CELL
RESEARCH
Includes Ethical implications as well
DISADVANTAGES OF STEM CELLS
Stem cells tend to divide indefinitely, leading
to a tumour
 The transplanted cells may differ from the
patient’s immune profile and thus get rejected
by the immune system.
 Unknown side effects and results from stem
cell usage.


Example: stem cell therapy may pass on disease
causing viruses or other microorganisms in an
individual’s body.
DISADVANTAGES (CONT’D)

A patient receiving transplants is subject to
drug intake that weaken the immune system,
necessary for a successful transplant.


Clearly, if any diseases causing viruses are present in the
transplanted cells, then the immune system would not be
able to save the body.
The animal sources, used to provide nutrients
to the stem cells may contain potential diseases
which pass onto the individual receiving the
therapy.

Concern: Present diseases are not detected in the
screening of the stem cells
DISADVANTAGES (CONT’D)
It is possible that the stem cells differentiate
into the wrong type of tissue
 Currently, scientists are uncertain about how
the differentiation of stem cells can be
controlled.


Ex: In 2001, scientists claimed to have created
cells that produced insulin, which later on was
proved wrong because the cells had never
produced insulin, rather had absorbed it from the
environment.
DISADVANTAGES (CONT’D)

genetic dysfunctions are developed by the usage
of older stem cells that have been approved for
use.
As they divide, a tumour is developed due to the
genetic disorders, putting the cells at risk.
 Thus the consequences may be very dangerous in
stem cell transplants.

ETHICAL IMPLICATIONS

People believe that life begins at conception
and therefore research on human embryos is
unethical.
They believe that early-stage embryos, known as
blastocycts, have the potential to grow into a
human being.
 It is inhumane to kill one life in order to save
another.

• Destroying the embryos signifies the
minor value of human life over
scientific research that de-values life.
ETHICAL IMPLICATIONS (CONT’D)


Additionally, animal testing is done in the
process of preparing or experimenting stem cells.
Arguments against stem cell research include the
idea that Embryos are divine creations.

It is against the will of god to destroy an embryo, and
thus they are not to be created or destroyed by
humans.
BIBLIOGRAPHY:





Benefits of Stem Cells. In: Explore Stem Cells [discussion list on the Internet]. n.d.;
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Ethical Implications of Stem Cell Research. In: ISCID - International Society for
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Key Ethical Issues in Embryonic Stem Cell Research. In: Commonwealth of
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http://www.aph.gov.au/library/pubs/CIB/2002-03/03cib05.pdf
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BIBLIOGRAPHY CONT’D
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
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


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