Download Stem Cells and Ethics

The diversity of cellular
life
Colonies of primitive unicellular organisms
don’t show emergent properties
 Prokaryotic organisms or
primitive eukaryotic
organisms (algae, protistae)
exist in colonies of identical
cells
 While the cells co-operate,
they do not fuse to form a
single mass and so don’t
form a single organism
 Each cell has identical
structure and function
Multicellular organisms have
differentiated cells
Cells are specialised:
 Blood cells
 Muscle cells
 Retinal cells
 Glandular cells
 Epithelial cells
Each cell type has a special
task and structure
Each cell has the same DNA,
but only a section of it is
expressed
Levels of ‘organisation’ in a
multicellular organism
1.CELL
2.TISSUE
3.ORGANS
4.ORGAN SYSTEMS
Cardiac myocytes
Heart
Cardiovascular system
4 key animal tissue types
1.Epithelial
2.Connective
3.Muscle
4.Nervous
Human Anatomy, Larry M.
Frolich, Ph.D.
Classes of Epithelia
 Simple: just one
layer or cell
shape
 Stratified:
multiple layers
and cell shapes
Human Anatomy, Larry M.
Frolich, Ph.D.
“ciliated” literally =
eyelashes
(see next page)
Stratified: regenerate from below
CONNECTIVE TISSUES
 “Areolar tissue” as model
 Universal in body
 Underlies epithelium, supports capillaries, small
nerves
Cells of Connective Tissues
 Fibroblasts make fibres – cartilage, ligaments, blood,
bone
 Immune cells in areolar tissue
Different types of Connective
tissues
Dense
 Ligaments
 Cartilage
 Bone
Human Anatomy, Larry M. Frolich, Ph.D.
Loose
 Fat
 Areolar
Tissue types
3. Muscle tissue
Skeletal
Cardiac
Smooth
Tissue types
3. Nervous tissue
Skeletal
Cardiac
Smooth
Neuroglia
Cell Differentiation
 Harvard Animation
What are stem cells?
 Cells that are able to generate more specialised types of
cell types through the process of cell differentiation
 Cells that can divide to make identical copies of
themselves, through self-renewal
 You can learn all about stem cells by watching the
beautiful animation from Utah Genetics here:
 Stem Cells
Different types of stem cells
1. Embryonic Stem Cells
 Here, you can learn how
embryonic stem cells are
made:
 Quck guide to Embryonic
stem cells
 Here is the BBC video on
how embryonic stem cells
are made:
 How to make stem cells
Different types of stem cells
2. Somatic Stem Cells
 (also called adult stem cells)
 Exist naturally in the body
 Used for bone marrow
transplants
 Can only differentiate into
dedicated cell types
Adult Stem Cells are committed to
become one type of cell
Stem cells in the adult brain:
Are they still working for us now?
Stem cells in mature skeletal muscle:
Is there power still in our stem cells?
Different types of stem cells
3. Induced pluripotential Stem
Cells
 Created artificially in the lab
by ‘reprogramming’ a
patients own cells
 Made from patient’s own
cells – fat, skin, fibroblasts
 Can become any cell in the
body (even a whole mouse!)
Induced pluripotential Stem
Cells – The future!
 Learn the story of iPS stem cells from Utah Genetics…
 IPS stem cells
Pros and Cons to iPS cell
technology
Pros:
 Cells would be genetically identical to patient or donor of skin
cells (no immune rejection!)
 Do not need to use an embryo
Cons:
 Cells would still have genetic defects
 One of the pluripotency genes is a cancer gene
 Viruses might insert genes in places we don’t want them
(causing mutations)
Different types of stem cells
4. Therapeutic Cloning: ‘patientspecific embryonic stem cells’
 Can theoretically create
pluripotent stem cells from
patient’s own cells
 Ethically highly controversial
 Scientists have not yet grown
a cloned human to the
blastocyst stage
Different types of stem cells
Stem Cells used in medicine: Treatment of
leukaemia
 Stem cell transplants have been
successfully used since 1968 to treat
patients with leukaemia
 Patients with leukaemia first have their own
abnormal blood cells destroyed by
radiotherapy
 Then the patients own bone marrow stem
cells are replaced with a transplant (into the
bloodstream) from a healthy patient’s bone
marrow
 If the transplant is successful, then the
stem cells will migrate into the bone marrow
and begin to produce new, healthy
leucocytes
 You can learn all about leukaemia
treatment by linking here onto Utah Inc:
 Utah Genetics
Stem Cells used in medicine:
Umbilical Cord Blood
 Umbilical cord blood stem
cell transplants have been
used for treatment of
leukaemia.
 Unbilical cord blood stem
cells are less prone to
immune rejection
 They are considered a potent
resource for transplant
therapies
Embryonic Stem cells are
pluripotent
What can we use Stem Cells
for?
 To provide lab-grown human or animal tissue for identifying new
treatments for disease (rather than using animals in research)
 TO produce new human tissue and organs to replace damaged
ones
 To repair tissue by stimulating stem cells already in the body
 To use stem cells from patients with inherited genetic diseases
(e.g. cystic fibrosis, some forms of Parkinson’s disease) to study
the disease
 To better understand diseases like cancer
 To investigate human development
Stem Cell Research is a fastmoving subject
 Stem cell grandparents
 Brand new sperm
 First trial of human embryonic stem cells
 Tracheal transplant
 Stem cell nobel prize
The Stem Cell Ethical Debate
The Ethical Questions
Until recently, the only way to get pluripotent stem
cells for research was to remove the inner cell mass
of an embryo and put it in a dish. The thought of
destroying a human embryo can be unsettling, even
if it is only five days old. Stem cell research thus
raised difficult questions:
• Does life begin at fertilization, in the womb, or at
birth?
• Is a human embryo equivalent to a human child?
• Does a human embryo have any rights?
• Might the destruction of a single embryo be
justified if it provides a cure for a countless
number of patients?
• Since ES cells can grow indefinitely in a dish and
can, in theory, still grow into a human being, is
the embryo really destroyed?
Ethics and iPS: Problem solved?
With iPS cells now available as an alternative to hES cells, the
debate over stem cell research is becoming increasingly
irrelevant. But ethical questions regarding hES cells may not
entirely go away. Inevitably, some human embryos will still
be needed for research. iPS cells are not exactly the same as
hES cells, and hES cells still provide important controls: they
are a gold standard against which the "stemness" of iPS cells
is measured. Some experts believe it's wise to continue the
study of all stem cell types, since we're not sure yet which one
will be the most useful for cell replacement therapies. An
additional ethical consideration is that iPS cells have the
potential to develop into a human embryo, in effect producing
a clone of the donor. Many nations are already prepared for
this, having legislation in place that bans human cloning.
Key Ethical Questions (1)
MORALITY AND HUMANITY OF
EMBRYOS
1. At what point does an embryo/
blastocyst have full moral status?
2. Is there a ‘moral cut-off’ at 14 days
after fertilisation?
3. Does an embryo’s moral status
increase as it develops?
Key Ethical Questions (2)
1. Is there anything wrong with using spare embryos left
over from fertility treatment?
2. Is it morally justifiable to use embryonic stem cells as a
means to an end, if they will provide huge benefits from
human health?
3. Should we be using embryonic stem cells at all, if we
have the alternatives of stem cell lines derived from
umbilical cord blood or induced pluripotential stem cells?
Arguments about embryonic
cells
Arguments about Somatic Cell
Nuclear Transfer
Arguments about the Moral
Status of the Embryo (1)
Arguments about the Moral
Status of the Embryo (2)
Arguments about the moral
status of the embryo (3)
Arguments about the moral
status of the embryo (4)
Links on ethics related to Stem
Cell research
 Stem Cell Ethics Factsheet
 Ethics and Embryos Factsheet
 Are embryos human? – a conversation…