1. Stem Cells & Neurological Disorders
Said Ismail
Faculty of Medicine
University of Jordan

2. Stem Cells and Neurological Disorders
Outline:
Introduction
Types & Potency of Stem Cells
Embryonic Stem Cells
Adult Stem Cells
iPSCs
Tissue Engineering and Regenerative Medicine
Stem Cells & Neurological Disorders:
- Neural Stem Cells
- Examples of Therapeutic Applications
- Conclusion
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3. Stem Cells and Neurological Disorders
Introduction
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Benefits of stem cell research :
Treatment of complex diseases:
Chronic Disorders: Diabetes
Neurological Disorders:
Alzhimer’s
Parkinson’s
Spinal Cord Injuries
Heart disorders: MI
Regenerative medicine (Spare parts !)
Skin Cartilage
Bone Cornea
Heart Valves
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5. Stem Cells and Neurological Disorders
Definition:
stem cells:
renew itself indefinitely
(ii) differentiate to multiple tissue types
A stem cell is not committed to
a specific function until it receives
a signal to differentiate into a
specialized cell
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6. Stem Cells and Neurological Disorders
Types & Potency
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Embryonic:
- Blastomere (4-5 day embryo)
- Pluripotent
Adult:
- Adult tissue
- multi or uni potent
Other :
- Fetal:
- Aborted embryos
- Umbilical:
- Umbilical cord blood
- Multipotent
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8. Stem Cells and Neurological Disorders
Potency:
1.Totipotent (Fertilized egg) Generate: - all embryonic cells and tissues - supporting tissue like placenta and umbilical cord 2. Pluripotent - Give rise to cells of all 3 germ layers (ecto-, meso-, and endoderm - Come from embryos and fetal tissue - Have active telomerase (maintain long telomers) 3. Multipotent - Give rise to multiple different cell types 4. Unipotent - Cell differentiating along only one lineage
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Embryonic Stem Cell
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13. Stem Cells and Neurological Disorders
The Embryonic Stem Cell Source: 1. IVF embryos 2. Aborted Fetus 3. Therapeutic cloning
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14. IVF embryos
Thousands of frozen embryos are routinely destroyed when couples finish their treatment.

15. Somatic Cell Nuclear Transfer
The nucleus of a donated egg is removed and replaced with the nucleus of a mature, "somatic cell" (a skin cell, for example).

16. Stem Cells and Neurological Disorders
Embryonic Stem Cell
First isolated and cultured in 1998
From inner cell mass of blastocyst (4-5 day embryo).
Pluripotent with long-term self-renewal
Capable of unlimited number of divisions without differentiation
Can essentially live forever without forming tumors
Maintain normal diploid complement of chromosomes (stable karyotype)
Telomerase activity
Clonogenic: give rise to genetically identical group of cells
Expresses transcription factor Oct-4 (+ or – genes needed for proliferative state)
Spend most of their time in S phase
In-Vitro: 300 population doublings
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17. Stem Cells and Neurological Disorders
Human Blastocyst showing Inner Cell Mass
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18. GROWING HESC IN VITRO:

19. Stem Cells and Neurological Disorders
Advantages:
Immortal: supply endless amount of cells
Flexible: can make any body cell
Available: IVF clinics
Disadvantages:
Hard to control their differentiation
Ethics
Immune rejection
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20. Stem Cells and Neurological Disorders
Avoiding Immune rejection:
Genetically engineering stem cell to:
a. Express MHC antigens of recipient
b. produces stem cells with deleted MHC genes
2. Therapeutic Cloning:
Clone somatic Cell nucleus of recipient into egg
develop into blastocyst and isolate ES cells
Such ES cells have recipient immunological profile
Co-transplantation with Hematopoitic Stem cells
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21. Avoiding Immune rejection

22. Stem Cells and Neurological Disorders
Laboratory tests to identify ESC :
1. Immortality: Sub-culturing stem cells for many months (long-term self-renewal)
2. Morphology: Inspecting culture by microscope (for undifferentiation)
3. Surface markers & Stemnss genes: (e.g. Oct-4)
4. Karyotype stability: Examining the state of chromosomes
5. Telomerase Activity
6. Pluripotency: testing differentiation potential into diff. cells types
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23. Stem Cells and Neurological Disorders
Ethics and ESCs:
Here Here or Here
When is it OK….when is it NOT
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Group of cells or Human life
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Adult Stem Cells
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The Adult Stem Cell
Undifferentiated cell found in a specialized tissue in adult.
Capable of self-renewal
Become specialized to cell types of the tissue from which it originated.
Properties:
Somatic
Long-term self-renewal
give rise to mature cell types
Generate intermediate cell (progenitors) “committed”
Can migrate whenever needed
Uni- or Multipotent
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29. Stem Cells and Neurological Disorders
Sources of adult stem cells :
Bone marrow
Blood stream
Umbilical cord blood
Dental pulp of the tooth
Cornea and retina
Skeletal muscle
Liver
Skin (epithelia)
Gastrointestinal tract
Pancreas
Brain & spinal cord
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Bone marrow
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umbilical cord blood
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32. Stem Cells and Neurological Disorders
Dental Pulp
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33. Stem Cells and Neurological Disorders

34. Adult stem cell plasticity
stem cell from one adult tissue can generate the differentiated cell types of another tissue:
“unorthodox differentiation” or “transdifferentiation”
EX. Hematopoietic stem cell Neurons
Possible under specific conditions
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35. Plasticity of adult stem cells
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Advantages :
No immune rejection
Available: eg HSC
Partly specialized: easier to control differentiation
Flexible: under the right conditions
Disadvantages :
Scarce (Rare): True for many Adult SCs
Unavailable: Some are difficult to isolate like Neural stem cells
Vanishing: Don’t live in culture as long as ES cells
Questionable quality: more prone to DNA abnormalities
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37. Induced Pluripotent Stem Cells Stem Cells and Neurological Disorders
(iPSCs)
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38. Stem Cells and Neurological Disorders
Induced Pluripotent Stem Cells (iPSCs): = Retro-differentiation = Re-programming
Producing stem cells from differentiated cells !!!
Pluripotent embryonic like stem cells are produced
Reversal of normal process
Does Not require human embryos
No donor…..No rejection
Less expensive
No Ethical issues
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39. Stem Cells and Neurological Disorders
Main Key Genes:
iPSCs are derived from adult somatic cells by inducing expression
of certain Stemness genes: (usually by viral vectors: risk !!!)
- eg: Master transcriptional regulators:
Oct-4
Sox2
Nonog
- other genes: c-Myc (oncogene: cancer risk !!!!)
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40. Stem Cells and Neurological Disorders
Pluripotency:
Believed to be identical to embryonic stem (ES) cells in many respects:
- expression of certain stemness genes
- chromatin methylation patterns
- doubling time
- embryoid body formation
- teratoma formation
- viable chimera formation
- potency and differentiability
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41. Stem Cells and Neurological Disorders
Generation of induced pluripotent stem (iPS) cells
Isolate and culture donor cells.
(2) Transfect stemness genes into cells by viral vectors. Red cells express those genes
(3) Harvest and culture the cells according to ES cell culture, on feeder cells (light gray)
(4) A subset of the transfected cells become iPS cells and generate ES-like colonies   
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42. Neurogenesis of iPS Pluripotent Neuronal Stem Cells derived from Adult Leukocytes

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Potential target disorders for Stem Cell Therapy:
Leukemia
Heart damage
Anemia
Cornea damage
Retinal damage
Parkinson’s
Alzhimer’s
Diabetes
Spinal Cord Injury
Kidney Failure
Skin grafts
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44. Stem Cells and Neurological Disorders
leukemia
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Heart damage
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Diabetes
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47. Regenerative Medicine Stem Cells and Neurological Disorders
Tissue Engineering
&
Regenerative Medicine
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Bone Repair
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Skin graft grown from stem cells
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Cornea
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trachea from stem cells
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A grown ear seeded with cartilage cells
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53. Neurological Disorders Stem Cells and Neurological Disorders
&
Neurological Disorders
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54. Which Stem Cell: Delivery Strategy: Graft type: 1. Neural stem cells
2. Other Adult SC (HSCs & MSCs)
3. Cord Blood SC
3. Embryonic SC
4. iPSCs
Delivery Strategy:
Injection into brain
Into Blood stream (Homing + immobilization by cytokines)
Graft type:
Stem cells + Biomaterial
Stem Cells + Gene therapy
All have been shown to
generate neural tissue
(Adult SCs are the mostly
used in clinical trials)
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55. Stem Cells and Neurological Disorders
Comparison:
Stem Cell  
Embryonic Pluirpotent Ethics
Fetal Pluripotent Ethics
Cord Blood Potent Rejection
Available
Adult Neural / Autologus Self low Numbers Same tissue Isolation
Adult (HSCs, MSCs,…) Easy isolation rejection (if allo.) Easy culture Plasticity ?!!
iPCs Pluripotent vector safety
Self
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56. Ongoing clinical
Trials in US and
the world 2012
Sanberg et al.
February 2012

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Different strategies for stem cell delivery to repair degenerated tissue
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Neural stem cells:
Generate new neural cells throughout the lifetime
Can migrate and replace dying neurons
Give rise to all types of neurons, astrocytes and oligodendrocytes, …
Capable of only Minor repairs
Their activity is up-regulated following injury
- Found in:
- Sub-ventricular zone of lateral ventricles (Most neurogenic area)
- Dentate gyrus of Hippocampus (2nd)
fewer in:
- Cerebellum   
- Spinal Cord
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Therapeutic Applications:
Main target disorders:
- Parkinson’s: localized degeneration (in substantia nigra) easier cell therapy
Huntington’s: clear etiology, single gene disorders (Gene/Cell Therapy)
Alzheimer : damage is less defined, widespread neuro-degeneration
Spinal Cord injuries: very promising prospects
Other: - Multiple Sclerosis (Siatskas and Bernard, 2009)
Ischemia / stroke
Epilepsy (Naegele et al., 2010)
Amyotrophic Lateral Sclerosis (ALS) (Wolfson et al., 2009).
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Parkinson’s:
Main Strategy:
- Replacing degenerated neurons with
dopamine-producing cells
Site:
- Substantia nigra: area were most degeneration occurs in PD
- Source of SCs:
- Pieces of fetal midbrain tissue (Mendez et al., 2005)
- Autologous adult neural stem/progenitor cells (Michel et al., 2009)
- Embryonic SCs (Friling et al. 2009)
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63. Stem Cells and Neurological Disorders
Huntington’s:
Good Model: well characterized single gene disorder
Main Strategy:
Blocking neuronal cell death & replacing lost neurons in striatum
- Source of SCs:
- SCs of fetal striatal primordium into striatum of HD patients
(Bachoud-Lévi et al., 2006)
- Autologous adult neural stem/progenitor cells
(Yu and Silva, 2008; Visnyei et al., 2006).
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64. Stem Cells and Neurological Disorders
Alzheimer’s:
Neuro-genesis in hippocampus deteriorates in AD patients
Example approaches: (Lunn et al., 2011)
1. Implanting Neural Stem Cells:
- Replace lost neurons
- Delay degeneration by producing Brain-Derived Neurotrophic Factor (BDNF)
2. Nerve growth factor (NGF) production:
- Genetically engineered patient fibroblasts that produce NGF …!!!
- Integration of NGF fibroblasts into a major cholinergic center of the basal
forebrain provided some benefit to AD patients
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65. Stem Cells and Neurological Disorders
Spinal cord injuries: (Salewski et al., 2010; Hu et al., 2010, Mathai et al 2008).
Stem cells can:
1. Replace neurons that died from injury
2. Generate supporting cells to re-form the myelin sheath & stimulate re-
growth of damaged nerves
3. Protect cells at injury site from further damage, by releasing protective factors
Stem cells under trials:
- Embryonic SCs
- Umbilical cord SCs
- Adult neural SCs
- Mesenchymal / bone marrow SCs
- induced pluripotent Scs
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66. Stem Cells and Neurological Disorders
Christopher Reeve
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67. Paralyzed Patients Walking Again Stem Cells and Neurological Disorders
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Conclusion:
Very promising clinical trial results in the last few years
More research needed to optimize diff. SC replacement protocols:
- Cell type
- Route
- No. of cells
- Single or multiple cell doses
Choice between ESCs / ASCs / iPSCs: yet to be resolved
Ethics (ESCs and Fetal tissue): Each Country has to decide
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69. Stem Cells and Neurological Disorders
THANK YOU
Stem Cells and Neurological Disorders