Transcript Stem Cells - tfss-g4p

Stem Cells
Ridhi Singh, Akshita Sahi,
Pavitura Kanagasabai, Siddhesh
Anand, Nimalan Chandrasekara,
Reuben Gurupatham
History of Stem Cells
• Scientists have been looking into stem cells since
the 1960s, this is because cell propagation and
differentiation were seen to be the building
blocks of humans
History of Stem Cells
• In 1963, a scientist named Dr.
Ernest McCulloch, discovered
stem cells but oddly that was
not the main goal of his
experiment.
▫ Medical Researcher at the
Ontario Cancer Institute in
Toronto, Canada.
History of Stem Cells
• Experiment: Exposed mice to powerful radiation
that all the blood and bone marrow cells were
killed. After, he injected normal house bone
marrow cells into some of the experimental mice
and irradiated bone marrow cells into others.
• Bone Marrow: where new blood cells are grown,
both in mice and people
History of Stem Cells
• Because radiation was used to kill cancer, Dr.
Ernest conducted the experiment to calculate
how sensitive bone marrow cells were to
radiation
• When examining the results, it was concluded
that there was no difference between mice with
irradiated bone marrow and mice with normal
bone marrow.
History of Stem Cells
• Dr. Ernest though realized that the mice’s
spleens had small whitish bumps in them.
• He also knew that mouse spleens and bone
marrow grew new blood cells
• After plotting the data on a graph, Dr. Ernest
concluded that the number of cell injections and
the number of spleen bumps had matched up.
History of Stem Cells
• This was the discovery of stem cells
• Though it was discovered in 1960, it wasn’t until
1963 that it was published (scientific papers)
• Proved that colonies were formed from single
cells that were able to duplicate themselves and
create colonies of different kinds of blood cells.
• They were called stem cells as new blood cells
‘stemmed’ from those cells.
History of Stem Cells
• This discovery set many scientists off to further
develop stem cells
• They were amazed at this particular property as
if they had developed it properly, could cure
cancer
What are stem cells?
• Cells in the body which have the capacity to
develop to many other types of cell in a body.
• Classified into 2 main types: Adult and
embryonic Stem cells
• Further research upon the functioning of these
cells can enable one in the future to make cells
and tissues for therapeutic purposes
Pictures/Diagram showing the
structure of a cell
• The Stem cells can be found in
the bone marrow.
• The cells are also known as the
future of medicine.
Importance
• In the body, stem cells are used for tissue
development and repair.
• As they are unspecialised
and undifferentiated, they
hold the potential to treat
countless medical conditions.
Cosmetic Uses
• Breast Implants
▫ Current breast implants are composed mainly of
silicone, which is unnatural and can cause side effects.
▫ Stem cells can be used to repair damaged breast tissue
and to enlarge breasts for cosmetic purposes.
• Hair Treatment
▫ Medical treatments and genetics can
cause hair loss.
▫ Stem cells can be used to repair damaged
scalp and create new hair follicles.
Medical Uses
• There are countless medical conditions than can
potentially be treated with stem cells.
• Cancer
▫ Stem cells replenish the blood cells of cancer patients,
as chemotherapy destroys both cancerous cells and
bone marrow cells.
• Organ
▫ As stem cells are undifferentiated and unspecialised,
they can become specified to fulfil the purpose of vital
organs, such as the liver.
▫ They can be used to repair damaged organs and can
even be used to create new organs for a patient.
Medical Uses – cont.
• Gene Therapy
▫ The stem cells of a patient with
a genetic disease and mixed with
a virus with the correct gene.
▫ Once the virus has transferred the
normal gene into the stem cells, the stem cells are
fused with the bone marrow.
▫ This is a promising procedure because it effectively
replaces the abnormal gene with the normal gene.
Research
• It is believed that birth defects and cancer are
due to an abnormal reproduction of stem cells.
• Further research of stem cells can allow more
effective treatments and cures to be developed.
• In addition, more
knowledge of the specific
causes for cancer can
allow researchers to
develop tips to prevent
such conditions.
Adult Stem Cells vs. Embryonic Stem
Cells
Adult Stem Cells
Embryonic Stem Cells
• Mulitpotent
▫ Cells are limited to the types
they can produce
• Abundance is rare
• Harder to identify
• No chance of immume
rejection
• Pluripotent
▫ Cells are able to produce
any type of cell
• Found abundantly
• Easier to identify
• High chance of immune
rejection
The Ethical Issue: Using Embryonic
Stem Cells
• Embryonic stem cells are those which are taken
from the embryo or fetus
• Most cells are taken from eggs that have been
through IVF with informed consent
• Debate about whether it is right to take away a life
that could have existed as the egg would have to be
destroyed in order to conduct research
▫ Can be seen as a human life being taken for the sake of
science
▫ People believe that it is not right to ‘play god’
• Most agree that the research, however, should
continue with limits
Applications of Stem Cells
• Stem cells are differentiated to turn
into specialized cells that are used
to recover damaged tissues and
organs.
• Turning genes on and off is central
to cell differentiation.
• Human stem cells are used to test
new drugs.
• Medications are tested for safety on
differentiated cells generated from
human pluripotent cell lines.
• Stem cells create the generation of
cells and tissues that could be used
for cell therapies.
• Differentiated stem cells provide a
renewable source of replacement
cells and tissues to treat diseases.
Applications of Stem Cells
• Stem cells can:
▫
▫
▫
▫
▫
▫
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renew blood and bones after chemotherapy
be used in skin replacement
be used in brain cell transplantation
provide dopamine for patients of Parkinson’s
disease
be used to possibly reverse blindness
be used in bone marrow transplants
be used in general to replace cells and tissues to treat
diseases including Alzheimer's diseases, spinal cord
injury, stroke, burns, skin and heart disease, diabetes,
osteoarthritis, rheumatoid arthritis, Parkinson's
disease, rheumatoid arthritis, muscular dystrophies
and liver diseases
After chemotherapy…
Bone marrow stem cells
• Stem cells offer the opportunity
of transplanting a live source for
self-regeneration.
• Bone marrow transplants
(BMT) are a well known clinical
application of stem cell
transplantation.
• BMT can repopulate the
marrow and restore all the
different cell types of the blood
after high doses of
chemotherapy, our main
defense used to eliminate
endogenous cancer cells
Skin replacement
• Stem cells made it possible for scientists to grow skin from a
patient’s plucked hair.
• Skin stem cells or keratinocytes reside in the hair follicle and
can be removed when a hair is plucked.
• These cells are cultured to form an epidermal same as the
patients own skin and provides tissue for an autologous graft,
avoiding problems of rejection.
• Autologous skin grafting is limited since only a fraction of the
skin can be repaired by this method and it creates additional
injuries at the donor sites.
Brain cell transplantation
• Neural stem cells were only
until recently thought to be
embryonic, but many
researchers prove otherwise.
• Applying stem cells for brain
cell transplantation is difficult.
• Potential targets of neural stem
cell transplants include stroke,
spinal cord injury, and diseases
like Parkinson’s Disease.
• So, neural stem cells can’t
easily be used in brain cell
transplantations.
A group of cultured adult
human neural stem cells.
Treating Parkinson’s Disease
• Stem cells provide dopamine, a chemical lacking
in victims of Parkinson’s Disease.
• Parkinson’s Disease involves the loss of cells
which produce the neurotransmitter dopamine.
• Fetal cell transplants for Parkinson’s Disease
reported survival and release of dopamine from
the transplanted cells.
• Use of stem cells for this disease has some side
effects which include autosensitization
(automatic immunization) to dopamine.
Reversing blindness
• Stem cells isolated from
the eyes can help
retinal regeneration.
• This can lead to a
possible cure for
damaged or diseased
eyes and may help
reverse blindness.
A human eye repaired using
stem cells.
Bone marrow transplants
• Bone marrow transplantation is a wellestablished treatment for blood cancers and
other blood disorders.
• Hematopoietic stem cells (HSCs) or blood stem
cells, present in the bone marrow are currently
the only type of stem cells commonly used for
therapy.
• HSCs are used to treat leukemia, lymphoma and
several inherited blood disorders.
Treating genetic skin diseases
Human epidermal
keratinocytes (HEK)
• Epidermolysis bullosa, which is
characterized by an extreme fragility
of the skin, is treated using skin stem
cells.
• Correction of a severe epidermolysis
bullosa can be achieved by
transplantation of genetically
modified keratinocyte stem cells.
• Genetically corrected skin tissue
heals perfectly well and biopsies from
the graft demonstrate that the
recombinant skin has a normal
histology and expression of the
transgene remains stable even a year
after treatment.
Organizations involved
• Stem cell research has been expanded to
international grounds as it has evolved.
• Some international organizations involved in
stem cell research and their applications include:
▫ International Stem Cell Forum
▫ ISSCR : The International Society for Stem Cell
▫ MRC: The UK Medical Research Council sponsors
the UK Stem Cell Bank
Nations involved in research
• Australia
▫ Australian Stem Cell Centre
• Canada
▫ Canadian Institutes of Health Research (CIHR)
• China
▫ Human Embryonic Stem Cell Research in China
• Europe
▫ EuroStemCell
Nations involved in research
• Japan
▫ RIKEN Center for Developmental Biology
• United Kingdom
▫ Centre for Stem Cell Biology (Part of the
University of Sheffield)
▫ Institute for Stem Cell Research
▫ Institute of Human Genetics at the University of
Newcastle upon Tyne
▫ UK National Stem Cell Network
Evolution of Stem Cells
• In the past, scientists have worked with two types of
stem cells (from animals and humans): embryonic
and non-embryonic stem cells
Embryonic Stem Cell
▫ Embryonic stem cell: undifferentiated cells derived
from an early-stage embryo
▫ Non-embryonic stem cell: rare undifferentiated cells
found in many organs and tissues
Evolution of Stem Cells
• Promising results from animal studies have
served as the basis for a small number of
exploratory studies in humans
• 1956: after experimenting with irradiated mice,
the first bone marrow transplant was performed
in New York
▫ Patient had leukemia and was treated with a bone
marrow from an identical twin
Evolution of Stem Cells
• 1960: it is discovered that bone marrow contains
at least two kinds of stem cells: blood or
haematopoietic stem cells
▫ both kinds form all the types of blood cells in the
body and stromal stem cells that form bone and
connective tissue
Evolution of Stem Cells
• 1968: British scientists became the first to
fertilise a human egg in a test tube
▫ Beginning of in-vitro fertilisation (IVF) technology
Human embryo used for IVF
• 1968: first ever bone marrow treatment used for
non-cancer treatment to treat an eight-year old
boy with a genetic disorder
Evolution of Stem Cells
• 1973: New York, first bone marrow transplant
between two unrelated patients (received from
donor in Denmark)
• 1978: first IVF baby born in England
• 1978: first blood stem cells are discovered in
human umbilical cord blood
Evolution of Stem Cells
• 1984-1998: retinoic acid is found to direct
pluripotent stem cells (most primitive cell) in
differentiation
Pluripotent stem cells
• 1989: pre-implantation genetic diagnosis (PGD) is
developed
▫ Single stem cell can be removed from an IVF embryo
and tested for inherited diseases
Evolution of Stem Cells
• 1990: bone marrow programme initiated
• 1995: scientists at the University of Wisconsin derive
the first embryonic stem cells from non-human
primates
• 1998: scientists at the University of Wisconsin
isolate and grow the first stem cells from human
embryos (from IVF)
▫ Embryos were created and used for reproductive
purposes
• 2001: US President George W. Bush permits
government funding of embryonic stem cell research
Evolution of Stem Cells
• 2004: California becomes first US state to provide
its own funding to embryonic stem cell research
• 2006: researchers discovered specialized adult cells
could be "reprogrammed" genetically to assume a
stem-cell like state---this new type of stem cell was
known as "induced pluripotent stem cells (IPSCs)“
In the Future...
• Research on how “cell-based therapies" could
treat disease
▫ also known as "regenerative or reparative
medicine"
• Have the potential to cure:
▫ Alzheimer's diseases, spinal cord injury, stroke,
burns, heart disease, diabetes, osteoarthritis,
rheumatoid arthritis...
In the Future...
• Stem cell research continues to advance
knowledge on the development of an organism
from a single cell and the replacement of
damaged cells in adult organisms
• Used in laboratories to test new drugs and to
develop model systems to study normal growth
and identify birth defect causes
In The Future...
• Scientific questions about the research are
growing as rapidly as its’ discoveries
• Human umbilical cord blood is rich in
hematopoietic (blood) stem cells and is currently
being used as an experimental alternative to
bone marrow transplantation, and is being
further researched
In The Future...
• Possibilities of the research being misused in the
future
• Could lead humanity to better treat/cure
diseases in future
▫ Gives social benefits for individuals and economic
gains for society
Concluding Statement
• Stem cell research sets the basis for medical
progress.
• These cells can be used to further study the
development of organisms.
• Through stem cell research, cures for several cell
diseases, such as cancer, may be discovered.
• Stem cells can be the key component in the
research and development of cytology.
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