Stem cells can differentiate into other types of cells and divide to produce more stem cells. There are two main types: embryonic stem cells which are pluripotent and can become any cell type but raise ethical issues, and adult stem cells which are multipotent and found in specific tissues where they aid in repair. Stem cell research aims to understand development and treat diseases like Alzheimer's, Parkinson's, diabetes, and spinal cord injuries by replacing damaged cells. Dental stem cells from the pulp have potential for tissue regeneration.

1. STEM
CELLS

2. contents
• Introduction
• Properties
• Potency
• Embryonic SC
• Adult SC
• Treatments
• Dental stem cells
• Research
• Conclusion
• References

3. Introduction
• Stem cells are biological cells that can differentiate into other types of
cells and can divide to produce more of the same type of stem cells.
• They are found in multicellular organisms.
• Stem cells playing a crucial role in homeostasis and tissue repair.

4. STEM CELL – DEFINITION
 A cell that has the ability to continuously divide
and differentiate (develop) into various other
kind(s) of cells/tissues

5. WHAT MAKES A CELL A STEMCELL?
• Plasticity: Stem cell - plastic, meaning - develop into another type of cell.
• Differentiation: Process where a stem cell specializes or develops into
another type of cell.
• Self-Renewal: Stem cell can divide (renew itself) indefinitely (go through
mitosis) & without always developing into another cell.

6. STEM CELL HISTORY
 1998 - Researchers first extract stem cells from human embryos
 1999 - First Successful human transplant of insulin-making cells from
cadavers
 2001 - President Bush restricts federal funding for embryonic stem- cell
research
 2002 - Juvenile Diabetes Research Foundation International creates $20
million fund-raising effort to support stem-cell research
 2004 - Harvard researchers grow stem cells from embryos using private
funding

7. WHAT ARE STEM CELLS?
• Stem cells - raw material from which all -
body’s mature, differentiated cells are made.
• Stem cells give rise - brain cells, nerve cells,
heart cells, pancreatic cells, etc.

8. MAJOR TYPES OF STEM CELLS
EMBRYONIC STEM CELLS
• Totipotent: cell can develop into all cell
cell types
• “Immortal”: can self-renew indefinitely
• Plentiful
ADULT STEM CELLS
• Multipotent: cell can develop into a
few cell types but not all
• Located in few organs or may be
unidentified
• Hard to find

9. STEM CELL – ARE DYNAMIC
 Undifferentiated
“master” cell that do not
yet have a specific
function
 Can change - one or several
different cell types
(differentiate) under proper
conditions
 Can undergo unlimited cell
division, self-renewal)

10. ONE CELL - SEVERAL LINEAGES

11. EMBRYOGENESIS AND DIFFERENTIATION
Specific regions of the embryo give rise to the specific organ systems
 Ectoderm generates - outer layer - embryo & produces - surface layer (epidermis) - skin

12. • TOTIPOTENT STEM CELLS - differentiate - embryonic & extraembryonic cell types. Such
cells - construct - complete, viable organism. Cells 1st few divisions - fertilized egg -
• PLURIPOTENT STEM CELLS - descendants - totipotent cells & differentiate - nearly all cells
i.e. cells derived from - three germ layers.
• MULTIPOTENT STEM CELLS - differentiate - number of cell types, - closely related family of
cells.
• OLIGOPOTENT STEM CELLS - differentiate - only a
few cell types - lymphoid or myeloid stem cells.
• UNIPOTENT CELLS - one cell type, - property of
self-renewal, which distinguishes - non-stem cells
(e.g.progenitor cells, which cannot self-renew)
Stem cell types – over view

13. THE SCIENCE OF STEM CELLS
 Stem cells - ability - continually reproduce themselves while maintaining
- capacity - give rise - other more specialized cells.
 Stem cells - found - all stages of development, from embryonic stem
(ES) cells that - differentiate - all specialized cells found - human body, to
adult stem cells capable - regenerating - tissue of origin.
 Stem cells occur - earliest stages - development & provide - starting

14. EMBRYONIC STEM (ES) CELLS
 ES cells - found - blastocyst stage, four - five
days after - union - sperm & egg, before -
embryo implants - uterus
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15. ES CELLS - "PLURIPOTENT" - I.E. CAPABLE OF FORMING EMBRYONIC
TISSUES

16.  Stem cells - derived from autologous, allogeneic
or xenogeneic sources.
 Histocompatibility - prerequisite - transplantation
- allogeneic stem cells.
 Fetal tissue is the best current tissue source for
human neural stem cells, however ethical issues
are a major concern.
SOURCE OF STEM CELLS

17. PLACENTA A SOURCE OF STEM CELLS
 Placental stem cells - umbilical cord
blood & bone marrow stem cells, - used
to cure chronic blood-related disorders
such as sickle cell disease, Thalassemia,
& leukaemia.

18. UMBILICAL CORD BLOOD STEM CELL TRANSPLANT
 Umbilical cord blood stem cell transplants -
less prone to rejection than either bone marrow
or peripheral blood stem cells.
 This is probably because - cells have not yet
developed - features - recognized & attacked -
recipient's immune system

19. • They have the potential to replace cell tissue that
has been damaged or destroyed by severe
illnesses.
• They can replicate themselves over and over for a
very long time.
• Understanding how stem cells develop into healthy
and diseased cells will assist the search for cures.
WHAT’S SO SPECIAL ABOUT STEM CELLS?

20. EMBRYONIC STEM CELLS
• Researchers extract stem cells - 5-7 days old blastocyst.
• Stem cells - culture - form more - own kind, thereby creating a stem cell
line.
• The research aims to induce these cells to generate healthy tissue needed
by patients.

21. • Adult stem cells - somatic or body stem cells.
• Some researchers - adult because - found after an
embryo develops - fetus & no longer - ESC.
• Some organs - believed - lack stem cells & replace dead
cells - mitosis.
ADULT STEM CELLS

22. • Adult stem cells develop into a few cell types.
• These Multipotent cells - used - bone-marrow
transplants & develop - all the blood cells.
• These cells - important, but some organs may not
have adult stem cells & these cells - difficult to find.
ADULT STEM CELLS

23. AUTOLOGOUS – STEM CELLS
 Sources - patient's own stem cells (autologous) - either
the cells from patient's own blood or bone marrow.
 For autologous transplants physicians - collect stem
cells - peripheral blood rather than the marrow.
 This procedure is easier, unlike a bone marrow
harvest.

24.  Sources of stem cells from another donor
(allogeneic) are primarily relatives (familial-
allogeneic) or completely unrelated donors
(unrelated-allogeneic).
 The stem cells in this situation are extracted from
either the donor's body or cord blood
ALLOGENEIC – STEM CELLS

25. • Stem cells from different species -
transplanted, e.g. striatal porcine fetal ventral
mesencephalic (FVM) xenotransplants for
Parkinson's disease.
• This has no major ethical concerns and a large
amount of tissue is available, however life
long immunosupression and risk of rejection
are the major limitations.
XENOGENEIC - STEM CELLS

26. HOW DOES CELL THERAPY WORK?
 Bone marrow transplants - example of cell therapy - donor's marrow
- used to replace - blood cells - victims of leukemia.
 Cell therapy - used in experiments - graft new skin cells to treat serious
burn victims, & grow new corneas for - sight-impaired.
 Goal is for the healthy cells to become integrated into body & begin -
function like pt's own cells.

27. MAJOR PROGRESS IN SEVERAL IMPORTANT HEALTH PROBLEMS
 Alzheimer’s
disease
 Parkinson’s
disease
 Spinal cord
injury
 Heart disease
 Severe burns
 Diabetes

28. ALZHEIMER’S DISEASE AND CAN STEM CELLS HELP?
 Stem cells could, however, be genetically
modified so as to deliver substances -
Alzheimer brain, to stop cells from dying &
stimulate - function of existing cells.
 A recent clinical trial - approach - some benefit
– pt's - Alzheimer’s disease, by slowing down -
progression - disease.

29. DRUG TESTING
Stem cells - allow scientists - test new drugs - human cell
line which could speed up new drug development.
Only drugs - safe & had beneficial effects - cell line
testing would graduate to whole animal or human
testing.
It would allow quicker & safer development - new
drugs.

30. STEM CELLS ACT AS PROGENITOR CELLS
 In adult organisms, stem cells and
progenitor cells act as a repair system for

31. APPLICATIONS OF STEM CELLS
Cell ReplacementTherapies
 Cells - stimulated - develop - specialized cells - represent renewable
sources - cells & tissue - transplantation.
 Cell replacement therapy could treat injuries & various genetic &
degenerative conditions including muscular dystrophies, retinal
degeneration, Alzheimer disease, Parkinson's disease, arthritis,
diabetes, spinal cord injuries, & blood disorders such as hemophilia.

32. DEVELOPMENT AND TESTING OF DRUGS
 Researchers could study the beneficial
and toxic effects of new medications on
human pluripotent stem cells that have
been developed to mimic the disease
processes.
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33. STEM CELLS – BLINDNESS
 In clinical trials - Moorfields Eye Hospital in
London, surgeons restored eye sight - six
patients - after chemical accidents & genetic
diseases.
 Patients - successful stem-cell transplant.
 Treatment - known as limbal stem cell therapy.
 By replacing - limbal stem cells, the cornea
begins to clear up as the cells - replaced -

34. Anatomy of dental pulp
• Dental pulp - centre of a tooth - living soft tissue & cells - odontoblasts.
• The central region - coronal & radicular pulp contains large nerve trunks & blood
vessels.
• This area is lined peripherally - aspecialized odontogenic area - four layers –zone of
odontoblastic layer, cell free zone, cell rich zone & Pulpal core.
Dental stem cells

35. • During tooth formation, interactions b/n epithelial & dental papilla cells promote tooth
morphogenesis by stimulating a subpopulation of mesenchymal cells to differentiate into
odontoblasts - form primary dentin.
• These odontoblasts - thought to arise - proliferation & differentiation - precursor
population, residing somewhere within the pulp tissue.

36. Types of dental stem cells
At least five different types of postnatal mesenchymal stem cells have been
reported to differentiated to odontoblast-like cells.
1. Dental pulp stem cells(DPSC)
2. Dental pulp of human exfoliated deciduous teeth(SHED)
3. Stem cells of apical papilla(SCAP)
4. Dental follicle progenitor cells(DFPC)
5. Bone marrow-derived mesenchymal stem cells(BMMCS)

37. 1. Dental pulp stem cells: (DPSCs)
• 1.Dental pulp stem cells: (DPSCs) - adult cell colony - potent capacity - self-
renewing & multilineage differentiation.
• Origin - DPSCs – not - determined & seem to be - source of odontoblasts -
contribute - dentin-pulp complex.
• Some studies - DPSCs - producing dental tissues in vivo including dentin, pulp, &
crown-like structures.
• Theoretically, a bio-tooth made from autogenous DPSCs should be the best choice

38. 2. Dental pulp of human exfoliated deciduous teeth
• Multipotent stem cells - human exfoliated deciduous teeth (SHED).
• Highly proliferative, clonogenic cells capable – differentiating - variety of
cell types including neural cells, adipocytes, and odontoblasts.
• Thus, exfoliated teeth may be - unexpected unique resource - stem-cell
therapies including autologous stem-cell transplantation & tissue
engineering.

39. 3. Stem cells of apical papilla
• A unique population - dental stem cells known as (SCAP) - islocated - tips -
growing tooth roots .
• Apical papilla tissue - present during root development before - tooth
erupts - oral cavity.
• SCAP - capacity - differentiate – odontoblasts and adipocytes.
• These cells - CD24+ but expression - downregulated upon odontogenic
differentiation – in vitro coincident with alkaline phosphatase upregulation.

40. 4. Dental follicle progenitor cells
• Dental follicle - loose ectomesenchyme-derived connective tissue sac
surrounding - enamel organ & dental papilla - developing tooth germ
before eruption.
• It is believed - contain progenitors for cementoblasts, PDL & osteoblasts.
• Dental follicle cells (DFC) form - PDL - differentiating - PDL fibroblasts -
secrete collagen & interact - fibres - surfaces of adjacent bone &
cementum

41. 5. Bone marrow derived cells
• BMDCs - potential - engraft - several tissues after injury, but - dental
tissue-specific progenitor cells - normal conditions & relationship - cells
to the tissue-resident cells - unknown.
• Bone marrow progenitor cells communicate - dental tissues & become
tissue-specific mesenchymal progenitor cells - maintain tissue
homeostasis.

42. INDICATIONS
Dental tissue repair:
• Dental stem cells - currently considered - potential for tissue regeneration.
• Repair damaged tooth tissues - dentine, PDL & dental pulp.
• Even enamel tissue engineering - suggested as well as - use of dental stem
cells as sources of cells to facilitate repair of non-dental tissues – bone.

43. 2.Periodontal regeneration:
• Periodontium - set - specialized tissues - surround & support - teeth to maintain
them - jaw.
• Periodontitis - inflammatory disease - irreversible loss - CT attachment &
supporting alveolar bone.
• One aim of current research - dental stem cells - replicate - key events -
periodontal development both temporally & spatially, so that healing can occur
- sequential manner to regenerate the periodontium.

44. 3.Regeneration of dental pulp
• Dental pulp needs – removed - infected, and particularly - root
pulp - requires endodontic treatment.
• A recent study demonstrated denovo regeneration of dental pulp
in emptied root canal space using dental stem cells .

45. 4. Whole tooth regeneration
• Current state - tooth replacement - dental implant - screwing a threaded
metal rod - predrilled hole in the bone - capped - plastic or ceramic
crown.
• Implants attach directly - bone without - PDL ‘shock absorber’ - forces -
mastication - transmitted directly – bone - one reason implants can fail.
• In case - insufficient bone for implants, such as tooth loss - consequence
- bone loss - occurs - postmenopausal osteoporosis, implants - preceded -
bone grafts.
• Ultimate goal - biologically replace lost teeth.

46. Techniques:
A. Idea - take adult stem cells - cell culture - programmed - develop - teeth &
transplanted - patients jaw - gap.
Placement tooth grows - happens - humans grow - original adult teeth.
Two - three months - tooth - fully develop.
Cost - more than existing treatments - attractive - other technologies such as
implants & dentures.

47. B. Tooth bud - implanted - jaw & gum stitched.
They - not started human clinical trials yet, however - expect - procedure - less
tooth extraction & requirements – post procedure - would be similar.
After implantation - takes - tooth about 3weeks - set - jaw of a mouse.
As long as - tooth - not under heavy load, it sets well.
Technology - grow replacement teeth - end of dentures.

48. Advantages.
1. It provides medical benefits - fields of therapeutic cloning & e-generative
medicine.
2. It provides great potential - treatments & cures - plethora of diseases including
Parkinsons disease, schizophrenia, Alzheimers disease, cancer, spinal cord injuries,
diabetes & many others
3. Regenerated pulp - re-build - damaged tooth from – inside.
4. Tooth - regenerated pulp - require markedly smaller restorations
5. Tooth - regenerated pulp - uphold the proprioceptive function - tooth

49. Disadvantages:
1. Use - ESC - destruction - blastocysts - laboratory- fertilized human eggs.
2. Like any other new technology, it is also completely unknown what the
long-term effects – interference - nature could materialize.
3. These are derived from embryos - not a patients own & patients immunity -
reject them.

50. POSSIBLE USES OF STEM CELL TECHNOLOGY
 Replaceable
tissues/organs
 Repair of defective cell types
 Delivery of genetic
therapies
 Delivery chemotherapeutic
agents
63

51. OBSTACLES OF STEM CELL RESEARCH
How to find the right type of stem cells?
How to put the stem cells into the right place?
Will the stem cells perform the desired function in the
body?
Differentiation protocols for many cell types have not
been developed.

52. • If stem cells have such potential to relieve
suffering, why are so many people so upset
about their use?
• The reason is that the most powerful type of
stem cell - embryonic stem (ES) cells - can only
be obtained from human embryos.
• Many people think that it's wrong to create and
destroy human embryos to treat disease
DESTROYING LIFE TO CURE SOME ONE – ETHICAL ?

53. FUTURE APPLICATIONS
Stem Cells may one day help scientists to regenerate cells lost in
diseases like:
• Repair heart muscle after a heart attack
• Pancreas cells lost in diabetes
• Neurons lost in Alzheimer’s
• Retinal cells causing blindness
• Understand the cell growths of cancers
• Help organ transplantation

54. conclusion
• Stem cells derived from all sources hold immense medical promises.
• Stem cell therapies have virtually unlimited medical & dental
applications.
• While there are several barriers that need to be broken down before this
novel therapy can be translated from lab to clinics, it is certain that the
future is going to be exciting for all of us.

55. References
1. Dental and skeletal stem cells : Potential cellular therapeutics for craniofacial
regeneration; Journal of Dental education, 2002; Vol. 66 (6): 766-773.
2. Stem cell based tissue engineering of murine teeth; J Dent Research, 2004; 83(7): 518-
522.
3. Mesenchymal stem cells acquire characteristics of cells in the periodontal ligament in
vitro; J Dent Research 2004; 83(1): 27-34.
4. Stem cells in craniofacial and dental tissue engineering; Orthod Craniofacial Res, 2005; 8:
54-59.
5. SHED: Stem cells from human exfoliated deciduous teeth: PNAS, 2003; 100 (10): 5807–