Download What is an adult stem cell?

Application of Neural Stem Cell
to the Treatment of
Urinary Incontinence &
Voiding dysfunction
Department of Urology
Soonchunhyang University
Song Yun Seob
What is a stem cell?
 A cell from the embryo, fetus, adult
 A cell that has the ability to divide (self replicate) for indefinite periods.
 SC can give rise (differentiate) to the many different cell types.
 Potential to develop into mature cells that have characteristic shapes
and specialized functions, such as heart cells, skin cells, or nerve cells.
Embryonic stem cell
Derived from a group of cells called the inner cell mass,
which is part of early embryo called blastocyst.
Embryonic germ cell
 Derived from fetal tissue
 Isolated from the primordial germ cells of the gonadal ridge of the 5 to
10 week fetus - gonadal ridge develops into the testes or ovaries
primordial germ cells give rise to eggs and sperm.
 EG cells are pleuripotent and share many of the characteristics of
human ESC - However, they are not identical in their properties and
characteristics.
Embryonal carcinoma cell
A type of pluripotent stem cell derived from teratocarcinoma
(usually a testis tumor)
Differentiation potential
 Totipotent
Meaning entire because it has the potential to generate all the cells and tissues
that make up an embryo and that support its development in utero including
extra embryonic tissues, placenta, and umbilical cord.
 Pleuripotent
A single SC has the ability to give rise to types of cells that develop from the
three germ layers (mesoderm, endoderm, and ectoderm) from which all the
body arise.
 Multipotent
Meaning the capability of developing cells of multiple germ layers.
Adult SC are typically unipotent and give rise to just one cell type under normal
conditions. However, if the replacement of multiple cell types is required, they
may become activated.
 Unipotent
A cell in a adult organisms capable of differentiating along only one lineage.
Research with ES cells
Research with EG cells
(Kerr et al, J Neurosci 2003)
- In a rat model of amyotrophic lateral sclerosis (ALS), rats are left with
paralyzed muscles.
- differentiated human EG cells that displayed the molecular markers of neural
SC
- injection of human EG cells into the fluid surrounding the spinal cords
- After 3 months, many of the injected rats were able to move and walk.
- At autopsy cells HEG cells had migrated throughout the spinal fluid and
continued to develop, displaying both the shape and molecular
markers characteristic of mature motor neurons.
What is an adult stem cell?
Adult SC
 can make identical copies of themselves for long periods of time.
 can give rise to mature cell types that have characteristic morphologies,
specialized functions.
Evidence for the presence of adult SC
 Three methods are used to determine whether candidate adult SC give
rise to specialized cells.
1. candidate adult SC can be labeled in vivo and then they can be tracked.
2. candidate adult SC can also be isolated, labeled, transplanted
back into the organism to determine what becomes of them.
3. candidate adult SC can be isolated, grown in vitro and manipulated, by
adding growth factors or introducing genes that help determine what
differentiated cells types they will yield.
 Adult SC have been identified in many animal and human tissues.
Distribution
 rare - 1 in 10,000 to 15,000 cells in the BM is a HSC.
 dispersed in tissues throughout the mature animal and behave very
differently, depending on their local environment.
Primary functions
 maintain the steady state functioning of a cell
 replace cells that die because of injury or disease with limitations.
 adult SC is somehow set aside during fetal development and restrained
from differentiating.
Clonogenic
A single adult SC can generate all the appropriate, differentiated cell types of
the tissue in which it resides.
 The list of adult SC
bone marrow
peripheral blood
brain
spinal cord
dental pulp
blood vessels
skeletal muscle
epithelia of the skin and digestive system
cornea
Retina
liver
pancreas
Research of adult stem cells
It should be demonstrated that adult SC
 fully integrated into the tissue
 give rise to fully differentiated cells that have mature phenotypes
 capable of specialized functions
The phenotype
 shape (morphology)
 interactions with other cells and the non-cellular environment
 proteins that appear on the cell surface (surface markers)
 cell’s behavior (secretion, contraction, synaptic transmission)
Neural adult stem cells
 Some parts of the adult human brain generate new neurons under certain
circumstances.
 These undifferentiated cells resemble cells in a developing fetus that give
rise to the brain and spinal cord.
 This includes neurons as well as neural-support cells called oligodendrocytes
and astrocytes.
 Adult neural SC can repair damage from degenerative diseases such as
Parkinson’s Disease or ALS as well as from brain and spinal cord injuries
resulting from stroke or trauma.
 Three groups of neural stem cells have been reported to date.
1. ventricles, regions known as the ventricular zone
2. subventricular zone. a streak of tissue that connects the lateral ventricle
and the olfactorybulb
3. hippocampus, a part of the brain thought to play a role in the formation of
certain kinds of memory
Fetal neural stem cells
 Neural SC are found in the fetal as well as the adult brain.
 Neural SC in the mammalian fetal brain are concentrated in
olfactory bulb
ventricular zone of the lateral ventricles
subventricular zone
hippocampus
spinal cord
cerebellum
cerebral cortex
Human fetal neural stem cells (Vescivi et al, J Neurotrauma 1999)
 isolated from the diencephalon and cortex of human fetuses, 10.5 weeks
 a serum-free growth medium that included EGF and FGF2 was devised to
grow the human fetal neural stem cells.
 neurospheres after one to two weeks in culture.
 differentiated cells consisted of astrocytes (75%), neurons (13%),
oligodendrocytes(1.2%).
 neurons generated expressed markers indicating GABA or catecholamine.
 maintained in vitro for a long time without differentiating, induced to
differentiate into the three major lineages of the nervous system in vivo.
 Bjorkland et al (Nature 2000)
Transplantation of fetal tissue into the damaged areas of the brains of rats
and monkeys used as models of the Parkinson’s disease could reverse
their Parkinson’s disease.
 Freed et al (N Eng J Med 2001)
 Human fetal brain SC from aborted seven to nine weeks after conception
 Patients with Parkinson’s disease receiving human fetal neural SC
transplants showed a clear reduction in the severity of their symptoms.
- increase in dopamine neuron function in the striatum by brain PET
 Autopsies revealed
- robust survival of the grafted neurons and sent outgrowths to target.
Adult stem cell plasticity
 Plasticity means that a SC from one adult tissue can generate the
differentiated cell types of another tissue.
 Evidence of adult SC plasticity
tracked in their new environment in vitro or in vivo
integrated into their new tissue environment
survived in the new tissue
structural and biochemical characteristics of the new tissue function
 Most of the studies that show the plasticity of adult SC involve cells that are
derived from the BM or brain.
 Neural SC lines cultured from adult brain tissue may differentiate to
many different cell types.
 If the phenomenon of plasticity is to be used as a basis for generating tissue
for transplantation
- it will need to be reproducible and reliable.
Plasticity of neural stem cell
Transfer of neural stem cells to the bladder or urethra
- Neural stem cell have plasticity and can differentiate to muscle
as well as nerves.
- Both of detrusor muscle and their supplied nerves can be repaired.
- Treatment of neuromuscular dysfunction of the bladder or urethra can be
expected.
Treatment of sphincteric incontinence
Periurethral injection
 Simple office procedures under local anesthesia
 The injected bulking agents include collagen, autologuous fat,
silicone microimplants, polydimethylsilixane, Teflon.
 The injected bulking agents cause passive occlusion of the urethra and
presumed to enhance mucosal sealing and coaptation.
Myoplasty for functional sphincter reconstruction
 Deming et al (1922) - gracilis muscle, transposed around the urethra
 Stenzl et al (1998) - unstimulated graciloplasty
 Janknegt et al (1995) - electrical stimulated muscle transfer
 Chancellor et al (1997) - gracilis muscle urethral wrap with pulse generator
 Palacio et al (1998) - free innervated flap of well-vasculized gracilis muscle
Periurethral injection of Stem cell
Transfer of neural stem cells to the periurethral area
- Neural stem cell have plasticity and can differentiate to muscle
as well as their supplied nerves.
- Both of detrusor muscle and their supplied nerves can be repaired
simultaneously.
- The injected neural stem cell cause active contraction of urethra as
well as passive occlusion of the urethra from mucosal sealing and
coaptation.
- The control of sphincteric incontinence can be expected.
Therapy to facilitate bladder emptying bladder
 Transfer of innervated skeletal muscle
Chancellor et al (1994) - rectus abdominis
Stenzl et al (1998) - latissimus dorsi
Van Savage et al (2000) - detrusor myoplasty with rectus muscle in cadavers
 Transfer of myoblast
Yokoyama et al(2000) - Myoplasty with myoblast
 Transfer of neural stem cells to the bladder
- Neural stem cell can differentiate to muscle as well as nerves.
- Both of detrusor muscle and their supplied nerves can be repaired
simultaneously.
- Therapy to facilitate bladder emptying bladder can be expected.
Diabetic Cystopathy
 Peripheral and autonomic neuropathy
- detrusor distention, overdistention, decompensation
 Loss of mylinated and unmyelinated fibers, wallerian degeneration
- blunted nerve fiber reproduction and function
 Currently, both a sensory and a motor neuropathy as being involved
in the pathogenesis
- motor aspect contributing to the impaired detrusor contractility
 Injection of neural stem cell into the bladder of a diabetic bladder may
promote the recovery of detrusor smooth muscles as well as peripheral
and autonomic neuropathy.
Direct Effects of Fluoxetine on
Electrophysiological properties
of Male Rat Major Pelvic Ganglia
Department of Urology, Soonchunhyang University
Yun Seob Song
Fluoxetine
 A kind of world-wide used SSRIs for treatment of depression
- exerts its effect increased concentration of serotonin by inhibiting
the reuptake of serotonin as well as norepinephrine in the CNS.
 SSRIs enhances external urethral sphincter activity in the cat through
serotonergic mechanisms, probably a central level (Campbell’s Urology 8th ed).
 SSRIs also produces a central mediated increase In bladder capacity through
a serotonergic mechanism (Campbell’s Urology 8th ed).
 SNRI such as duloxetine has the peripheral effects through the neurons in
Onuf’s nucleus of somatic nerves.
 As the inhibition of voltage-dependent Na+, K+ and Ca2+ channels by
fluoxetine has been reported, fluoxetine also may be expected to have an direct
effect on the peripheral neurons.
 This study was performed to determine whether fluoxetine have direct effects
on electrophysiological properties of neurons in MPG of autonomic nerves.
Major pelvic ganglia (MPG)
 take parts in the regulation of voiding as a relay center peripherally.
 When pathological processes involving these functions, alterations in MPG
neuronal structure and function have been observed.
 MPG provides a useful model for studying the peripheral physiological views of
the neural control of the voiding.
Major pelvic ganglion of male rat
Materials and Method
We examined the direct effect of fluoxetine on voltage-dependent Ca2+ and
K+ channels of MPG neurons using the patch-clamp technique
in the whole-cell configuration.
Figure. Patch-clamp technique in the whole-cell configuration
Conclusions
 Direct inhibition of Ca2+ and K+ currents by fluoxetine in MPG.
 Fluoxetine has the effects on the neurons in MPG through direct action of
fluoxetine as well as increased serotonin concentration.
 These new physiological findings may be expected for the development
of new drug.