Stem Cell Technology

1. Stem Cell Stem Cell
TechnologyTechnology

2. About the presenterAbout the presenter
Dr.B.Victor is a highly experienced postgraduate biology Dr.B.Victor is a highly experienced postgraduate biology
teacher, recently retired from the reputed educational teacher, recently retired from the reputed educational
institution St. Xavier’ s College, Palayamkottai, institution St. Xavier’ s College, Palayamkottai,
India-627001.India-627001.
He was the dean of sciences and assistant controller of He was the dean of sciences and assistant controller of
examinations.examinations.
He has more than 32 years of teaching and research He has more than 32 years of teaching and research
experienceexperience
He taught a diversity of courses ranging from pre- He taught a diversity of courses ranging from pre-
university to post graduate classes.university to post graduate classes.
Send your comments to : [email protected] your comments to : [email protected]

3. Presentation outlinePresentation outline
Stem cell characteristicsStem cell characteristics
Embryonic stem cells Embryonic stem cells
(ESC)(ESC)
Adult Stem cells (ASC)Adult Stem cells (ASC)
Stem Cell LinesStem Cell Lines
Classification of stem Classification of stem
cells cells
Culture andCulture and
Stem cell therapy Stem cell therapy
Recent DevelopmentsRecent Developments

4. Diversity of Human CellsDiversity of Human Cells
Adult humans consist of more than 200 kinds of cells.Adult humans consist of more than 200 kinds of cells.
They are nerve cellsThey are nerve cells ( (neuronsneurons), ), muscle cellsmuscle cells
((myocytesmyocytes), ), skinskin (epithelial) (epithelial) cellscells, , blood cellsblood cells
(erythrocytes, (erythrocytes, monocytesmonocytes, , lymphocyteslymphocytes, etc.), , etc.), bone bone
cellscells ( (osteocytesosteocytes), and ), and cartilage cellscartilage cells ( (chondrocyteschondrocytes).).
cells essential for embryonic development but not cells essential for embryonic development but not
incorporated into the body of the embryo, include incorporated into the body of the embryo, include
the the extra-embryonic tissuesextra-embryonic tissues, , placentaplacenta, and umbilical , and umbilical
cord. cord.
All of these cells are generated from a single, All of these cells are generated from a single,
totipotent cell, totipotent cell, the the zygotezygote, or fertilized egg. , or fertilized egg.

6. What is a stem cell?What is a stem cell?
A A stem cell is a "blank" cell/ precursor stem cell is a "blank" cell/ precursor
cell that can give rise to multiple tissue cell that can give rise to multiple tissue
types such as a skin, muscle, or nerve types such as a skin, muscle, or nerve
cell.cell.
 A stem cell is essentially the building A stem cell is essentially the building
block of the human body. block of the human body.

7. Features of Stem CellsFeatures of Stem Cells
1.1.Stem Cells are very unique cells.Stem Cells are very unique cells.
2.2. Stem Cells have the amazing ability to develop into Stem Cells have the amazing ability to develop into
several distinct cell types in the body. several distinct cell types in the body.
3.3.Stem Cells can be used as a repair system for the Stem Cells can be used as a repair system for the
body.body.
4.4. Stem Cells can theoretically divide without limit in Stem Cells can theoretically divide without limit in
a living organism in order to replenish various a living organism in order to replenish various
types of cells. types of cells.
5.5.When a stem cell divides, each new cell has the When a stem cell divides, each new cell has the
potential to either remain a stem cell or become potential to either remain a stem cell or become
another type of cell with a more specialized another type of cell with a more specialized
function (i.e. a muscle cell, a red blood cell, a brain function (i.e. a muscle cell, a red blood cell, a brain
cell, etc.). cell, etc.).

9. Three unique properties of stem cellsThree unique properties of stem cells
 Stem cells are capable of Stem cells are capable of dividing and dividing and
renewing themselves for long periodsrenewing themselves for long periods;;
 They are They are ““unspecialized”unspecialized” and they can and they can
give rise to specialized cell types. give rise to specialized cell types.
 A stem cell is A stem cell is "uncommitted,""uncommitted," until it until it
receives a signal to develop into a receives a signal to develop into a
specialized cell.specialized cell.

10. Asymmetric division ofAsymmetric division of
stem cells stem cells
Stem cells have the ability to Stem cells have the ability to
divide asymmetrically .divide asymmetrically .
One portion of the cell division One portion of the cell division
becomes a differentiated cell becomes a differentiated cell
while the other becomes while the other becomes
another stem cell.another stem cell.

11. 1. Stem cells are unspecialized1. Stem cells are unspecialized
A stem cell A stem cell does not have any tissue-specific does not have any tissue-specific
structuresstructures that allow it to perform specialized that allow it to perform specialized
functions. functions.
A stem cell cannot work with its neighbors to A stem cell cannot work with its neighbors to
pump blood through the body (pump blood through the body (like a heart like a heart
muscle cell); muscle cell);
It cannot carry molecules of oxygen through It cannot carry molecules of oxygen through
the bloodstream (the bloodstream (like a red blood celllike a red blood cell); and); and
 It cannot fire electrochemical signals to other It cannot fire electrochemical signals to other
cells that allow the body to move (cells that allow the body to move (like a nerve like a nerve
cell).cell).

12. 2.2.Stem cells are capable of dividing and Stem cells are capable of dividing and
renewing themselves for long periods.renewing themselves for long periods.
Stem cells may replicate many times. Stem cells may replicate many times.
When cells replicate themselves many times it When cells replicate themselves many times it
is called proliferation. is called proliferation.
The stem cells that proliferate for many The stem cells that proliferate for many
months in the laboratory can yield millions of months in the laboratory can yield millions of
cells. cells.
Stem cells are capable of long-term self-Stem cells are capable of long-term self-
renewal.renewal.

13. 3.3.Stem cells can give rise to Stem cells can give rise to
specialized cellsspecialized cells

When unspecialized stem cells give rise to specialized When unspecialized stem cells give rise to specialized
cells, the process is called cells, the process is called differentiation. differentiation.
There are signals inside and outside cells that trigger There are signals inside and outside cells that trigger
stem cell differentiation.stem cell differentiation.
 The The internal signalsinternal signals are controlled by a cell's genes. are controlled by a cell's genes.
The The external signalsexternal signals include chemicals secreted by include chemicals secreted by
other cells, physical contact with neighboring cells, other cells, physical contact with neighboring cells,
and certain molecules in the microenvironmentand certain molecules in the microenvironment

14. In embryosIn embryos, stem cells function to , stem cells function to
generate new organs and tissues. generate new organs and tissues.
 In adultsIn adults, they function to replace , they function to replace
cells during the natural course of cell cells during the natural course of cell
turnover. turnover.
4.Stem cells exist in both embryos
and adults.

15. Distinguishing Features of Distinguishing Features of
Progenitor/Precursor Cells and Stem Cells.Progenitor/Precursor Cells and Stem Cells.
A stem cellA stem cell is an unspecialized cell that develops is an unspecialized cell that develops
into a variety of specialized cell types. into a variety of specialized cell types.
a stem cell divides and gives rise to one additional a stem cell divides and gives rise to one additional
stem cell and a specialized cell. stem cell and a specialized cell.
Example:Example: a hematopoietic stem cell produce a a hematopoietic stem cell produce a
second generation stem cell and a neuron. second generation stem cell and a neuron.
A progenitor cell (a precursor cellA progenitor cell (a precursor cell)) is unspecialized is unspecialized
that is capable of undergoing cell division and that is capable of undergoing cell division and
yielding two specialized cells. yielding two specialized cells.
Example:Example: a myeloid progenitor/precursor cell a myeloid progenitor/precursor cell
undergoing cell division to yield two specialized undergoing cell division to yield two specialized
cells (a neutrophil and a red blood cell). cells (a neutrophil and a red blood cell).

17. Stem cell ClassesStem cell Classes

18. Embryonic Type stem cellsEmbryonic Type stem cells
1.Embryonic Type
Embryonic Stem Cells Embryonic Germ Cells

19. 2. Adult Type
Umbilical Cord Stem Cells
Placental Stem Cells Adult Stem Cells
Adult type Stem cellsAdult type Stem cells

20. Sources of embryonic type stem Sources of embryonic type stem
cellscells
* * Embryos -Embryos - Embryonic stem cells are obtained Embryonic stem cells are obtained
by harvesting living embryos which are by harvesting living embryos which are
generally 5-7 days old. The removal of generally 5-7 days old. The removal of
embryonic stem cells invariably results in the embryonic stem cells invariably results in the
destruction of the embryo.destruction of the embryo.
* Fetuses -* Fetuses - Another kind of stem cell, called an Another kind of stem cell, called an
embryonic germ cell, can be obtained from embryonic germ cell, can be obtained from
either miscarriages or aborted fetuses. either miscarriages or aborted fetuses.

21. Sources of adult type stem cellsSources of adult type stem cells
Umbilical Cords, Placentas and Amniotic Umbilical Cords, Placentas and Amniotic
Fluid -Fluid - Adult type stem cells can be derived Adult type stem cells can be derived
from various pregnancy-related tissues.from various pregnancy-related tissues.
Adult Tissues -Adult Tissues - In adults, stem cells are In adults, stem cells are
present within the bone marrow, liver, present within the bone marrow, liver,
epidermis, retina, skeletal muscle, intestine, epidermis, retina, skeletal muscle, intestine,
brain, dental pulp and elsewhere. brain, dental pulp and elsewhere.
Cadavers -Cadavers - Neural stem cells have been Neural stem cells have been
removed from specific areas in post-mortem removed from specific areas in post-mortem
human brains as late as 20 hours following human brains as late as 20 hours following
death. death.

22. Comparison of embryonic and Comparison of embryonic and
adult stem cellsadult stem cells
Advantages of Embryonic Stem Cell Advantages of Embryonic Stem Cell
1. Flexible1. Flexible - appear to have the potential - appear to have the potential
to make any cell.to make any cell.
2. Immortal2. Immortal - one embryonic stem cell - one embryonic stem cell
line can potentially provide an endless line can potentially provide an endless
supply of cells with defined supply of cells with defined
characteristics.characteristics.
3. Availability 3. Availability - embryos from - embryos from in vitroin vitro
fertilization clinics. fertilization clinics.

23. Disadvantages of Embryonic Disadvantages of Embryonic
Stem CellStem Cell
–Difficult to differentiate uniformly and Difficult to differentiate uniformly and
homogeneouslyhomogeneously into a target tissue. into a target tissue.
–Immunogenic -Immunogenic - embryonic stem cells embryonic stem cells
from a random embryo donor are likely from a random embryo donor are likely
to be rejected after transplantationto be rejected after transplantation
–Tumorigenic Tumorigenic - capable of forming tumors - capable of forming tumors
or promoting tumor formation.or promoting tumor formation.
–Destruction of developing human lifeDestruction of developing human life. .

24. Advantages of Adult Stem CellAdvantages of Adult Stem Cell
–Adult stem cells from bone marrow and umbilical Adult stem cells from bone marrow and umbilical
cords appear to be as cords appear to be as flexible as the embryonic flexible as the embryonic
typetype
–Somewhat specialized -Somewhat specialized - inducement may be inducement may be
simpler.simpler.
– Not immunogenic -Not immunogenic - recipients who receive the recipients who receive the
products of their own stem cells will not products of their own stem cells will not
experience immune rejection.experience immune rejection.
– Relative ease of procurementRelative ease of procurement - some adult stem - some adult stem
cells are easy to harvest (skin, muscle, marrow, cells are easy to harvest (skin, muscle, marrow,
fat) fat)
– Non-tumorigenic-Non-tumorigenic-tend not to form tumors.tend not to form tumors.
– No harm doneNo harm done to the donor. to the donor.

25. Disadvantages of Adult stem cells
1. Limited quantity1. Limited quantity - can - can
sometimes be difficult to obtain in sometimes be difficult to obtain in
large numbers.large numbers.
2. Finite - 2. Finite - may not live as long as may not live as long as
embryonic stem cells in culture.embryonic stem cells in culture.
3. Less flexible - 3. Less flexible - may be more may be more
difficult to reprogram to form other difficult to reprogram to form other
tissue types tissue types

26. Why are adult stem cells preferable to Why are adult stem cells preferable to
embryonic stem cells?embryonic stem cells?
Adult stem cells are naturally exist in our Adult stem cells are naturally exist in our
bodies, and they provide a natural repair bodies, and they provide a natural repair
mechanism for many tissues. mechanism for many tissues.
They belong in the microenvironment of an They belong in the microenvironment of an
adult body, while embryonic stem cells adult body, while embryonic stem cells
belong in the microenvironment of the early belong in the microenvironment of the early
embryo, where they tend to cause tumors embryo, where they tend to cause tumors
and immune system reactions.and immune system reactions.

27. Superior features of ESCsSuperior features of ESCs
Embryonic stem cells are easier to Embryonic stem cells are easier to
identify, isolate and harvest.identify, isolate and harvest.
There are more of them.There are more of them.
They grow more quickly and easily in They grow more quickly and easily in
the lab than adult stem cells.the lab than adult stem cells.
They can be more easily manipulated They can be more easily manipulated
(they are more plastic)(they are more plastic)

28. Classification based on level Classification based on level
of differentiationof differentiation
 TTotipotentotipotent
 PluripotentPluripotent
 Multipotent Multipotent
 Unipotent stem cellsUnipotent stem cells

29. Types of Stem cells

30. Totipotent stem cellsTotipotent stem cells
•The fertilized egg is said to be The fertilized egg is said to be totipotent totipotent
from the Latin from the Latin totus,totus, meaning meaning “entire”.“entire”.. .
• It has the potential to generate all the cells It has the potential to generate all the cells
and tissues that make up an and tissues that make up an embryoembryo. .
• It supports embryonic development It supports embryonic development in in
uteroutero. .

31. Pluripotent stem cellsPluripotent stem cells
Pluripotent stem cellsPluripotent stem cells are descendants of are descendants of
the totipotent stem cells of the embryo. the totipotent stem cells of the embryo.
These cells develop about four days after These cells develop about four days after
fertilizationfertilization
They can differentiate into any cell They can differentiate into any cell
type, except for totipotent stem cells and type, except for totipotent stem cells and
the cells of the placenta.the cells of the placenta.

33. Pluripotent stem cellsPluripotent stem cells
 ““Pluri”Pluri” is derived from the Latin is derived from the Latin
plures plures means means several or many. several or many.
Thus, pluripotent cells have the Thus, pluripotent cells have the
potential to give rise to any type of cell. potential to give rise to any type of cell.

34. Pluripotent stem cellsPluripotent stem cells
These cells cannot re-create a These cells cannot re-create a
complete organism but differentiate complete organism but differentiate
to a large number of mature tissue to a large number of mature tissue
types, for example, brain and types, for example, brain and
muscle. muscle.

36. Multipotent stem cellsMultipotent stem cells
Multipotent stem cells are Multipotent stem cells are descendents of descendents of
pluripotent stem cells and antecedents of pluripotent stem cells and antecedents of
specialized cells inspecialized cells in particular tissues. particular tissues.
For example, hematopoietic stem cells, which For example, hematopoietic stem cells, which
are found primarily in the are found primarily in the bone marrow,bone marrow,
give rise to all of the cells found in the give rise to all of the cells found in the
blood,including red blood cells, white blood blood,including red blood cells, white blood
cells, and platelets.cells, and platelets.

37. Unipotent stem cellUnipotent stem cell
Unipotent stem cellUnipotent stem cell,, a term that is a term that is
usually applied to a cell in adult usually applied to a cell in adult
organisms, means that the cells in organisms, means that the cells in
question are capable of differentiating question are capable of differentiating
along only one lineage. along only one lineage.
"Uni""Uni" is derived from the Latin word is derived from the Latin word
unus,unus, which means one. which means one.

38. Progenitor cellsProgenitor cells
Progenitor cellsProgenitor cells (or (or
unipotent stem cellsunipotent stem cells) can ) can
produce only one cell type. produce only one cell type.
For example, For example, erythroid erythroid
progenitor cellsprogenitor cells differentiate differentiate
into only red blood cells.into only red blood cells.

39. Blood is made in the Bone Marrow-Blood is made in the Bone Marrow-
Blood Cell DevelopmentBlood Cell Development

40. ““Terminally differentiated" cellsTerminally differentiated" cells
At the end of the long chain of cell At the end of the long chain of cell
divisions are divisions are "terminally "terminally
differentiated"differentiated" cellscells, such as a liver cell , such as a liver cell
or lung cell, which are permanently or lung cell, which are permanently
committed to specific functions.committed to specific functions.

41. Adult stem cells (ASC)Adult stem cells (ASC)

42. Adult stem cells or Adult stem cells or
somatic stem cellssomatic stem cells
Adult stem cells are undifferentiated cells.Adult stem cells are undifferentiated cells.
They are found in They are found in small numberssmall numbers in most in most
adult tissues.adult tissues.
They can also be extracted from umbilical They can also be extracted from umbilical
cord blood. cord blood.
They are also called They are also called “somatic stem cells,”“somatic stem cells,”
They are multipotent in nature. They are multipotent in nature.
They give rise to a closely related family of They give rise to a closely related family of
cells within the tissuecells within the tissue. .
An example is hematopoietic stem cells, An example is hematopoietic stem cells,
which form all the various cells in the blood.which form all the various cells in the blood.

44. Adult stem cell plasticity and Adult stem cell plasticity and
transdifferentiationtransdifferentiation
This ability to differentiate into This ability to differentiate into
multiple cell types is called multiple cell types is called
plasticity or plasticity or
transdifferentiationtransdifferentiation..

45. DifferentiationDifferentiation
pathways of adult stem cells pathways of adult stem cells
Neural stem cellsNeural stem cells in the brain give rise to its three major in the brain give rise to its three major
cell types: nerve cells (neurons) and two categories of cell types: nerve cells (neurons) and two categories of
non-neuronal cells — astrocytes and oligodendrocytes. non-neuronal cells — astrocytes and oligodendrocytes.
Epithelial stem cellsEpithelial stem cells in the lining of the digestive tract in the lining of the digestive tract
occur in deep crypts and give rise to several cell types: occur in deep crypts and give rise to several cell types:
absorptive cells, goblet cells, Paneth cells, and absorptive cells, goblet cells, Paneth cells, and
enteroendocrine cells. enteroendocrine cells.
Skin stem cellsSkin stem cells occur in the basal layer of the epidermis occur in the basal layer of the epidermis
and at the base of hair follicles.and at the base of hair follicles.
 The epidermal stem cellsThe epidermal stem cells give rise to keratinocytes, give rise to keratinocytes,
which migrate to the surface of the skin and form a which migrate to the surface of the skin and form a
protective layer.protective layer.
 The follicular stem cellsThe follicular stem cells can give rise to both the hair can give rise to both the hair
follicle and to the epidermis follicle and to the epidermis

46. The similarities and differences between
embryonic and adult stem cells
Embryonic stem cellsEmbryonic stem cells can become all cell types of can become all cell types of
the body because they are the body because they are pluripotentpluripotent..
 Adult stem cells are generally limited to Adult stem cells are generally limited to
differentiating into different cell types of their differentiating into different cell types of their
tissue of origin. tissue of origin.
However, some evidence suggests that adult stem However, some evidence suggests that adult stem
cell cell plasticityplasticity may exist, increasing the number of may exist, increasing the number of
cell types a given adult stem cell can become.cell types a given adult stem cell can become.

47. Human embryonicHuman embryonic and and adult stem adult stem
cellscells
A potential advantage of using stem cells from an A potential advantage of using stem cells from an
adult is that the patient's own cells could be adult is that the patient's own cells could be
expanded in culture and then reintroduced into expanded in culture and then reintroduced into
the patient.the patient.
The use of the patient's own adult stem cells The use of the patient's own adult stem cells
would mean that the cells would not be rejected by would mean that the cells would not be rejected by
the immune system. the immune system.
Embryonic stem cells from a donor introduced Embryonic stem cells from a donor introduced
into a patient could cause transplant rejection. into a patient could cause transplant rejection.

48. Umbilical cord stem cells
Blood from the placenta and umbilical cord Blood from the placenta and umbilical cord
that are left over after birth is a rich source that are left over after birth is a rich source
of hematopoietic stem cells. of hematopoietic stem cells.
 These so-called These so-called umbilical cord stem cellsumbilical cord stem cells
have been shown to be able to differentiate have been shown to be able to differentiate
into bone cells and neurons, as well as the into bone cells and neurons, as well as the
cells lining the inside of blood vessels.cells lining the inside of blood vessels.

49. Importance of Importance of
Cord blood stem cellsCord blood stem cells
Cord blood stem cells have been used to Cord blood stem cells have been used to
treat 70 different diseases, including treat 70 different diseases, including
leukemia, lymphoma, and inherited leukemia, lymphoma, and inherited
diseases (of red blood cells, the immune diseases (of red blood cells, the immune
system, and certain metabolic system, and certain metabolic
abnormalities). abnormalities).
Cord blood collection is a safe, simple Cord blood collection is a safe, simple
procedure that poses no risk to the mother procedure that poses no risk to the mother
or newborn baby.or newborn baby.

50. Embryonic Stem Cells (ESC). Embryonic Stem Cells (ESC).

51. Embryonic Stem CellsEmbryonic Stem Cells
Embryonic Stem Cells are derived from Embryonic Stem Cells are derived from
embryos that develop from eggs that have embryos that develop from eggs that have
been fertilized been fertilized in vitroin vitro..
 Embryonic Stem Cells are never derived Embryonic Stem Cells are never derived
from eggs fertilized inside of a woman's body. from eggs fertilized inside of a woman's body.
The embryos from which Human Embryonic The embryos from which Human Embryonic
Stem Cells are derived are typically four or Stem Cells are derived are typically four or
five days old and are a hollow microscopic five days old and are a hollow microscopic
ball of cells called the blastocyst ball of cells called the blastocyst

52. Embryonic stem cells (ESC)Embryonic stem cells (ESC)
Embryonic stem cells (ESC), as their name Embryonic stem cells (ESC), as their name
suggests, are derived from embryos.suggests, are derived from embryos.
 Specifically, embryonic stem cells are derived Specifically, embryonic stem cells are derived
from embryos that develop from eggs that have from embryos that develop from eggs that have
been fertilized been fertilized in vitro in vitro —donated for research —donated for research
purposes with informed consent of the donors.purposes with informed consent of the donors.
 They are They are not not derived from eggs fertilized in a derived from eggs fertilized in a
woman's body. woman's body.

55. Properties of Embryonic Stem Properties of Embryonic Stem
CellsCells
a Derived from the inner cell mass of the blastocyst. a Derived from the inner cell mass of the blastocyst.
a Capable of undergoing an unlimited number of a Capable of undergoing an unlimited number of
symmetrical divisions without differentiating (long-symmetrical divisions without differentiating (long-
term self-renewal). term self-renewal).
Exhibit and maintain a stable, full (diploid), normal Exhibit and maintain a stable, full (diploid), normal
complement of chromosomes (karyotype). complement of chromosomes (karyotype).
Pluripotent ES cells can give rise to differentiated Pluripotent ES cells can give rise to differentiated
cell types that are derived from all three primary cell types that are derived from all three primary
germ layers of the embryo (endoderm, mesoderm, germ layers of the embryo (endoderm, mesoderm,
and ectoderm). and ectoderm).

56. Potential sources of stem cells are:Potential sources of stem cells are:
fetal tissue that becomes available after an abortion fetal tissue that becomes available after an abortion
excess embryos from assisted reproductive technologies excess embryos from assisted reproductive technologies
such as commonly used in fertility clinics such as commonly used in fertility clinics
embryos created through in vitro fertilization specifically embryos created through in vitro fertilization specifically
for research purpose, and for research purpose, and
embryos created asexually as a result of the transfer of a embryos created asexually as a result of the transfer of a
human somatic cell nucleus to an egg with its own nucleus human somatic cell nucleus to an egg with its own nucleus
removed.removed.
Other sources of stem cells are those from umbilical cord Other sources of stem cells are those from umbilical cord
blood, and bone marrow.blood, and bone marrow.
In addition, neural stem cells, haematopoetic stem cells In addition, neural stem cells, haematopoetic stem cells
and mesenchymal stem cells can be harvested from fetal and mesenchymal stem cells can be harvested from fetal
blood and fetal tissue.blood and fetal tissue.

58. Cell therapy.Cell therapy.
Treatment of neural diseases such as Treatment of neural diseases such as
Parkinson's disease, Huntington’s disease and Parkinson's disease, Huntington’s disease and
Alzheimer's disease. Alzheimer's disease.
Stem cells could be used to repair or replace Stem cells could be used to repair or replace
damaged neurons.damaged neurons.
Repair of damaged organs such as the liver Repair of damaged organs such as the liver
and pancreas. and pancreas.
Treatments for AIDS. Treatments for AIDS.

59. Stem cell transplantation (SCT)Stem cell transplantation (SCT)
Stem cell transplantation (SCT) is the term Stem cell transplantation (SCT) is the term
now used in preference to bone marrow now used in preference to bone marrow
transplantation (BMT). transplantation (BMT).
When a patient's bone marrow fails to When a patient's bone marrow fails to
produce new blood cells, for whatever reason, produce new blood cells, for whatever reason,
he or she will develop anaemia, be prone to he or she will develop anaemia, be prone to
frequent, persistent infections and may frequent, persistent infections and may
develop serious bleeding problems.develop serious bleeding problems.
 In order to restore blood cell production a In order to restore blood cell production a
patient may be given healthy stem cells. patient may be given healthy stem cells.

60. Therapeutic cloning/ somatic cell Therapeutic cloning/ somatic cell
nuclear transfernuclear transfer
Scientists first remove Scientists first remove the nucleusthe nucleus from a normal egg from a normal egg
cell of a womancell of a woman. They then extract . They then extract a nucleus from a a nucleus from a
somatic cellsomatic cell - that is, any body cell other than an egg - that is, any body cell other than an egg
or sperm—from a patient who needs an infusion of or sperm—from a patient who needs an infusion of
stem cells to treat a disease or injury, and stem cells to treat a disease or injury, and insert the insert the
nucleus into the egg. nucleus into the egg.
The egg, which now contains the patient's genetic The egg, which now contains the patient's genetic
material, is allowed to divide and soon forms a hollow material, is allowed to divide and soon forms a hollow
sphere of cells called a sphere of cells called a blastocystblastocyst..
 Cells from Cells from the inner cell massthe inner cell mass are isolated and used are isolated and used
to develop new embryonic stem cell (ESC) lines.to develop new embryonic stem cell (ESC) lines.

61. Strategy for therapeutic cloning Strategy for therapeutic cloning
and tissue engineeringand tissue engineering

62. Stem cells and cancer treatmentStem cells and cancer treatment
Intense chemotherapy damages a person’s bone Intense chemotherapy damages a person’s bone
marrow, where the stem cells for blood reside.marrow, where the stem cells for blood reside.
Depleted of a fresh supply of blood cells, the patient is Depleted of a fresh supply of blood cells, the patient is
left vulnerable to infection, anemia and bleeding. left vulnerable to infection, anemia and bleeding.
These side effects of chemotherapy are often treated These side effects of chemotherapy are often treated
with a bone marrow transplant.with a bone marrow transplant.
“ “Transplanting bone marrow tissue into a chemo-Transplanting bone marrow tissue into a chemo-
cancer patient may involve hundreds of thousands or cancer patient may involve hundreds of thousands or
millions of cells – of which only two or three may be millions of cells – of which only two or three may be
actual stem cells. actual stem cells.
It would be much more efficient if you could inject a It would be much more efficient if you could inject a
thousand purified stem cells,”thousand purified stem cells,”

63. Therapeutic cloning for tissue
repair
One human organ, skin, is readily One human organ, skin, is readily
cultured to provide replacement tissue cultured to provide replacement tissue
for burns victims.for burns victims.
Healthy skin cells from the patient can Healthy skin cells from the patient can
be grown rapidly be grown rapidly in vitro in vitro to provide self-to provide self-
compatible skin grafts.compatible skin grafts.

64. Is Stem Cell Research Ethical?Is Stem Cell Research Ethical?
* * Embryonic Stem CellsEmbryonic Stem Cells - - always morally objectionable, always morally objectionable,
because the human embryo must be destroyed in order to because the human embryo must be destroyed in order to
harvest its stem cells.harvest its stem cells.
* * Embryonic Germ CellsEmbryonic Germ Cells - - morally objectionable when morally objectionable when
utilizing fetal tissue derived from elective abortions, but utilizing fetal tissue derived from elective abortions, but
morally acceptable when utilizing material from spontaneous morally acceptable when utilizing material from spontaneous
abortions (miscarriages) if the parents give informed consent.abortions (miscarriages) if the parents give informed consent.
* * Umbilical Cord Stem CellsUmbilical Cord Stem Cells - - morally acceptable, since the morally acceptable, since the
umbilical cord is no longer required once the delivery has been umbilical cord is no longer required once the delivery has been
completed.completed.
* * Placentally-Derived Stem CellsPlacentally-Derived Stem Cells - - morally acceptable, since morally acceptable, since
the afterbirth is no longer required after the delivery has been the afterbirth is no longer required after the delivery has been
completed.completed.
* * Adult Stem CellsAdult Stem Cells - - morally acceptable. morally acceptable.

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