neural stem cells as a possible medical treatment of parkinson's disease

8/14/2019 neural stem cells as a possible medical treatment of parkinson's disease

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Stem Cells asStem Cells as

A Possible Medical TreatmentA Possible Medical Treatment

of Parkinsons Diseaseof Parkinsons Disease

Leonardo PlatonLeonardo Platon

Major in Cell and Molecular BiologyMajor in Cell and Molecular Biology

Undergraduate Seminar in BiologyUndergraduate Seminar in Biology


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SignificanceSignificance

Parkinsons disease is one of the leading

neurological disorder today. Through the seminar,

the audience will be informed on how neural stem cell

transplantation can address the cause of this disorderby replacing degraded dopamine neurons and

providing neuroprotection to existing ones. This

seminar summarizes significant experimental studies

in animal models which demonstrate safety andefficacy prior to human clinical trials.


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ObjectivesObjectives

To characterize and identify uses of neural stem cells

To describe how stem cell transplantation can be a

potential treatment to Parkinsons disease To present studies showing the application of stem

cells in treatment of model animals with Parkinsons

disease


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Neural Stem CellsNeural Stem Cells

Stem cells are capable of generating variouscommitted progenitor cells and ultimatelydifferentiate into mature cells

Neural stem cells are not only present in thedeveloping mammalian central nervous system butalso in the adult nervous system of all mammalian

organisms including humans

Neural stem cells can also be derived from moreprimitive embryonic stem cells


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Fig. 1. An illustration proposing the classes of mammalianFig. 1. An illustration proposing the classes of mammalian

stem cells that can give rise to neurons.stem cells that can give rise to neurons.


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The location of adult stem cells and the brain regions towhich their progeny migrate is still unclear but a number ofviable locations have been identified.

In the adult mammalian brain, the genesis of new neurons has

been consistently documented in the subgranular layer of thedentate gyrus and the subventricular zone of the lateralventricles

The subventricular zone is the adult brain region with thehighest neurogenetic rate, from neural stem cells had first

been isolated

Neural stem cells are also found in the spinal cord

Location of Neural Stem CellsLocation of Neural Stem Cells


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Fig. 2. View of the adult rodent brain that depicts (in gray) theFig. 2. View of the adult rodent brain that depicts (in gray) theregions where continous neurogenesis occurs throughoutregions where continous neurogenesis occurs throughout

adulthood which are the olfactory bulb and the hippocampus.adulthood which are the olfactory bulb and the hippocampus.

Areas known to contain NSCs (in black) are the subventricularAreas known to contain NSCs (in black) are the subventricular

zone and the dentate gyrus of the hippocampus.zone and the dentate gyrus of the hippocampus.


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1) Cells are harvested from human

brain tissue or the spinal cord

2) Cell suspension is stained with

monoclonal antibodies (mAbs)

3) Proprietary mAbs are placed in cells

sorter which separates non-stem cells

from stem cells

4) Cells are cultured and readied for

transplantation

Isolation of Neural Stem CellsIsolation of Neural Stem Cells


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Fig. 3. Procedure for isolation of neural stem cells.Fig. 3. Procedure for isolation of neural stem cells.


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Brain sites targeted for stem cell transplantation of

different studies vary in location. Common sites of

transplantation are areas of the brains wheredopamine neurons degrade such as the substantia

nigra and corpus striatum

Specific dosage of stem cells to be transplanted isstill to be determined

Transplantation of Neural StemTransplantation of Neural Stem

CellsCells


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A total of 5x105 GDNF-c17.2 NSCswere grafted in four deposits in the

striatum of mice models

Single intrastriatal injection of 4ug of6-OHDA to induce Parkinsons disease

Fig. 4. Neural stem cell transplation procedureFig. 4. Neural stem cell transplation procedureused by Akerud et al. (2001).used by Akerud et al. (2001).


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Medical Properties of NeuralMedical Properties of Neural

Stem CellsStem Cells

As the central nervous systems most primordialcells, neural stem cells have attributes that appearto promote anatomical and functional preservationor restoration in neurodegenerative diseases

Multipotent neural stem or progenitor cell lines candifferentiate to neuronal and glial phenotypes, bothin vitro and after transplantation into thedeveloping or adult brain

Possible medical applications is also based on thefact that neurogenesis still continues duringadulthood within restricted areas of the centralnervous system


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Present Knowledge on NeuralPresent Knowledge on Neural

Stem CellsStem Cells

It is presently known that isolated fetus or adult-

derived neural stem cells from rat, mouse and

human brain tissue survive well in the developingand adult, intact or damaged brain and can migrate

over sizable distances

Neural stems may need to be accustomed toneighboring cells of transplantation site to induce

their differentiation toward specific lineages and to

function properly


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About 60,000 Americans are newly diagnosed withParkinsons disease each year with more than 1.5million Americans affected at any one time.

In 2002, there was an estimated 200 total deaths or0.3 per 100,000 people in the Philippines died due tothe disease.

It is estimated that four million people worldwidehave Parkinsons disease.


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Parkinsons DiseaseParkinsons Disease

Parkinsons disease is a degenerative disorder of the centralnervous system. It is characterized by a massivedegeneration of dopamine-containing neurons in thesubstantia nigra which is in the mid-brain

It is both a chronic, meaning it persists over a long period of

time, and progressive, meaning its symptoms grow worseover time

The disease by itself does not cause people to die. However,general physical and emotional condition of people who areseverely affected can cause or exacerbate other illnesses and

so contribute to the final cause of death

Parkinsons is not contagious. Some cases appear to behereditary but most cases are sporadic.


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What causes Parkinsons?What causes Parkinsons?

Degeneration of dopamine (DA) neurons in the substantia nigra (SN) andthe consequent deficit of DA release appear to be responsible for thecharacteristic manifestations of Parkinsons disease.

Dopamine is a chemical messenger responsible for transmitting signalsbetween the substantia nigra and the next relay station of the brain, the

corpus striatum, to produce smooth and purposeful movement

Dopamine work in balance with acetylcholine to transmit messagesbetween nerve cells and muscles. The transmitted messages allow forperformance of coordinated movements. In people with Parkinsons,this balance is upset because of the degeneration of dopamine neuronsleading to lack of dopamine release.

Loss of dopamine results in abnormal nerve firing patterns within thebrain that cause impaired movement. Neurons are not well-regulatedand do not behave in a normal manner.

The reason why dopamine neurons degenerate in the brain of people

with Parkinsons is still unknown.


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Fig. 5. Neuronal pathways that degenerate in ParkinsonsFig. 5. Neuronal pathways that degenerate in Parkinsons

disease.disease.


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What are the symptoms of theWhat are the symptoms of the

disease?disease? Parkinsons disease does not affect everyone in the

same way and the rate of progression differs amongpatients.

1) Tremor is one of the primary symptoms and isusually the reason that causes people to seekmedical help.

2) Rigidity or resistance to movement affects most

people with Parkinsons disease.

3) Postural instability or impaired balance causespatients to fall off easily. A stooped posture inwhich the head is bowed and the shoulders are

drooped may develop in affected persons.


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Hoehn and Yahr Staging ofHoehn and Yahr Staging of

Parkinsons DiseaseParkinsons Disease Stage 1 symptoms on one side of the

body only

Stage 2 symptoms on both sides of

the body. No impairment of balance Stage 3 balance impairment. Still

physically independent

Stage 4 severe disability but still ableto walk or stand unassisted

Stage 5 wheelchair-bound orbedridden unless assisted


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How is Parkinsons diseaseHow is Parkinsons disease

diagnosed?diagnosed?

There is currently no blood or laboratory tests thathave been proven to help in diagnosing the disease

The diagnosis is based on medical history and aneurological examination

The disease is difficult to diagnose since itssymptoms can also been as signs of normal aging

Doctors may sometimes request brain scans to ruleout other diseases. However, CT and MRI brainscans of people with Parkinsons disease usuallyappear normal


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Findings of Recent StudiesFindings of Recent Studies


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Neuroprotection through Delivery of Glial Cell-LineNeuroprotection through Delivery of Glial Cell-Line

Derived Neurotrophic Factor By Neural Stem CellsDerived Neurotrophic Factor By Neural Stem Cells

in a Mouse Model of Parkinsons Diseasein a Mouse Model of Parkinsons Disease

By Akerud et al. (2001)

Objective: to demonstrate that neural stem cells engineered

to release glial cell line-derived neurotrophic factor (GDNF)

can differentiate into multiple, stable neural cells and prevent

degeneration of dopaminergic neurons in the substantia nigra


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Materials and MethodsMaterials and Methods

A total of 5x105 GDNF-c17.2 NSCswere grafted in four deposits in the

striatum of mice models

56 mice models (32 grafted and 24non-grafted) received a single

intrastriatal injection of 4ug of 6-OHDA

to induce Parkinsons disease

Neuroprotective effects of GDNF-

c.17 NSCs on substantia nigra

dopaminergic neurons were

characterized through

immunohistochemistry


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ResultsResults

Morphological analysis of brains engrafted with GDNF-c17.2NSCs after 30 days showed that the NSCs was able to survivethroughout the striatum

Immunohistochemisty showed that GDNF-c17.2 NSCsdifferentiated into different types of multipotent neural stemcells

Grafting of GDNF-c17.2 NSCs was able to protect the substantianigra dopaminergic neurons from degradation


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Fig. 6. Immunochemistry showed that GDNF-c17.2 NSCs giveFig. 6. Immunochemistry showed that GDNF-c17.2 NSCs give

rise to neurons (D), astrocytes (E) and oligodendrocytes (F).rise to neurons (D), astrocytes (E) and oligodendrocytes (F).


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Fig. 7. Grafts of GDNF-c17.2 NSCs protected SN dopaminergicFig. 7. Grafts of GDNF-c17.2 NSCs protected SN dopaminergic

neurons against degradation done by 6-OHDA.neurons against degradation done by 6-OHDA.


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ConclusionsConclusions

Neural stem cells engineered to release GDNF were

able to survive and differentiate to different neural

cell types

GDNF-c17.2 NSCs was also able to provide

neuroprotection to the substantia nigra dopaminergic

neurons against degradation


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Transplantation of Human Neural Stem CellsTransplantation of Human Neural Stem Cells

Exerts Neuroprotection in a Rat Model ofExerts Neuroprotection in a Rat Model of

Parkinsons DiseaseParkinsons Disease

By Yasuhara et al. (2006)

Objective: to demonstrate the neuroprotective effects of

transplanted HB1.F3 human neural stem cells lines against

dopaminergic degradation in rats induced with Parkinsons

disease


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72 Sprague Dawley rats received 6-hydroxydopamine (6-OHDA) injections in the right

medial forebrain to induce Parkinsons disease

32 of the rats immediately received HB1.F3 NSCs

transplantation while 40 of the rats served as

control

morphological analysis to show degree of dopaminergic preservation


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ResultsResults

Staining of the striatum and analyzed at three different coronalsection levels, demonstrated that the dopaminergic nigrostriatalsystem of the HB1.F3 transplanted rats was significantlypreserved in all levels examined

Thyroxine hydroxylase fibers in the striatum and neurons in thesubstantia nigra were preserved by HB1.F3 cell grafts

HB1.F3 cells were able to survive in the lesioned striatum


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Fig. 8. HB1.F3 cell grafts were able to preserve theFig. 8. HB1.F3 cell grafts were able to preserve the

dopaminergic nigrostriatal system. Dopamine neurons in thedopaminergic nigrostriatal system. Dopamine neurons in the

SN of rats that received HB1.F3 cell grafts were markedlySN of rats that received HB1.F3 cell grafts were markedly

preserved (C and F) compared with vehicle-treated rats (B andpreserved (C and F) compared with vehicle-treated rats (B and

E).E).


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ConclusionConclusion

Transplanted human neural stem cells in rat models

was able to exert significant neuroprotection against

dopaminergic degradation


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Behavioral Improvement in a Primate ParkinsonsBehavioral Improvement in a Primate Parkinsons

Model is Associated with Multiple HomeostaticModel is Associated with Multiple Homeostatic

Effects of Human Neural Stem CellsEffects of Human Neural Stem Cells

By Redmond et al. (2007)

Objective: to demonstrate that Parkinson-induced adult

monkey brain retains intrinsic microenvironmental signals

that may direct differentiation of an uncommitted human

neural stem cell (hNSCs) toward a dopamine (DA) phenotype

and that hNSCs have the capacity to respond to DA deficiency

resulting to significant functional and behavioral recovery


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25 African green monkeys were injectedsystematically with 1-methyl-4-phenyl-1,2,3,6-

tetrahydropyridine (MPTP) to induce Parkinsonsdisease

behavioral scoring and statistical analysis

transplantation or injection of hNSCs in to the right substantia nigra

histological analysis


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ResultsResults

Observations of monkeys with Stage 5 Parkinsons diseaseshowed greater improvements in activities of daily living

(such as ability to sit, walk and self-feed) compared to shamoperated monkeys


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Fig. 9. Comparison of behavioral recovery in severelyFig. 9. Comparison of behavioral recovery in severely

Parkinsonian monkeys after hNSC injections and sham-Parkinsonian monkeys after hNSC injections and sham-

operated monkeys.operated monkeys.
http://www.pnas.org/content/vol104/issue29/images/large/zpq0240766650001.jpeg


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Histological sections from the brains of the monkeys wereanalyzed to further understand the basis of the behavioral andfunctional recovery

Histological analysis showed that hNSCs, which aretransplanted in monkeys with severe Parkinsons disease,could survive, migrate and yield dopamine neurons


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Fig. 10. Survival and migration ofFig. 10. Survival and migration of

hNSCs into the nigrostriatalhNSCs into the nigrostriatal

system. hNSCs were injectedsystem. hNSCs were injected

unilaterally, dorsal to the rightunilaterally, dorsal to the right

substantia niagra (white arrow).substantia niagra (white arrow).

Migration of donor-derived cellsMigration of donor-derived cells

(green stars).(green stars).

Figure 11. Some transplanted hNScs

showed key markers of DA neurons.


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ConclusionsConclusions

Uncommitted human neural stem cells (hNSCs) were

able to differentiate to dopamine phenotype because

of certain microenvironmental signals

Differentiation of hNSCs to dopamine neurons led to

capacity to respond to dopamine deficiency which

resulted to behavioral and functional recovery

R fReferences


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ReferencesReferencesAkerud, Peter. 2001. Neuroprotection through delivery of glial cell line-

derived neurotrophic factor by neural stem cells in a mouse

model of Parkinsons disease. Journal of Neuroscience. 21(20):

8108-8118.

Gage, Fred. 2000. Mammalian neural stem cells. Science. 287(5457):1433-

1438.

Galli, Rossella. 2003. Neural stem cells. Circulation Research. 92:598.

Redmond, Eugene et al. 2007. Behavioral improvement in a primate

Parkinsons model is associated with multiple homeostatic effects of

human neural stem cells. PNAS. 104(29): 12175-12180.

Sanberg, Peter. 2007. Neural stem cells for Parkinsons disease: to

protect and repair. PNAS. 104(29): 11869-11870.

Uchida, Nobuko. 2000. Direct isolation of human central nervous

system stem cells. PNAS. 97(26): 14720-14725.

Yasuhara, Takao et al. 2006. Transplantation of human neural stem cells

exerts neuroprotection in a rat model of Parkinsons disease. Journal ofNeuroscience. 26 48 : 12497-12511.


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neural stem cells as a possible medical treatment of parkinson's disease