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Stem Cells:
"Repairmen of the Body"
Young or old, most people will
suffer from pain caused by wear
and tear on joints and
ligaments. For
some, it is a gradual,
degenerative process; cartilage
is lost to the point where bone
rubs on bone, or ligaments and
tendons fray in and around
knees, shoulders, ankles, and
hips. For others,
pain and tissue damage comes
quickly through an acute injury
such as partial tear of
ligaments in the knee, the
rotator cuff of the shoulder, a
disc herniation in the neck or
back, or chipping off a chunk of
cartilage within a joint.
Regardless of the cause,
these degenerative conditions are
debilitating and painful, often
requiring lengthy periods of
curtailed activity and
rehabilitation.
Surgical interventions, if even an
option, are not always successful at
fully repairing the damage and
alleviating the pain.
In short, athletes with these
degenerative conditions often have
to decrease, or even stop
altogether, the activities that they
have grown to love.
How Are These Conditions
Treated?
Traditionally,
definitive treatment has been
surgery. In
general, surgeries will either
1) replace what is damaged or
missing, as in the case of ACL
replacement, 2) stitch what is
torn, as with a rotator cuff
repair, or 3) remove what is
torn or detached, as with
arthroscopic debridement of
frayed or torn knee menisci.
Newer surgical repair
techniques include microfracture
and cartilage transplant.
While they have had some
success, they are also invasive
and require a lengthy
rehabilitation process
Stem Cell Basics
Stem cells
are primal cells found in
all multi-cellular organisms.
They retain the ability to renew
themselves through mitotic cell
division and can differentiate
into a diverse range of
specialized cell types.
The three broad categories of
mammalian stem cells are:
embryonic stem cells, derived
from blastocysts, adult stem
cells, which are found in adult
tissues, and cord blood stem
cells, which are found in the
umbilical cord. In a developing
embryo, stem cells can
differentiate into all of the
specialized embryonic tissues.
In adult organisms, stem cells
and progenitor cells act as a
repair system for the body,
replenishing specialized cells.
Stem cells are, in essence,
the building blocks of the body.
In adults, they are produced
in the bone marrow, fat, and
joint fluid. When released into
the bloodstream, they migrate to
areas that need repair.
Research has shown that
they hone in on areas of injury,
and are more effective if placed
at or near the damaged site. [
] Once there, they
become whatever kind of tissue
needs help regenerating itself.
Mesenchymal stem cells
(MSCs) are the class of stem
cells that most commonly repair
cartilage, bones, and muscle.
As we age, we produce
fewer and fewer MSCs, which
explains, in large part, why we
have more trouble healing
ourselves now than when we were
children.
Stem Cells In Human
Medicine
For many
years, researchers and
clinicians have known that stem
cells can repair and regenerate
damaged tissues. Most of these
experiments have been done in
animal models. Research has
shown that stem cells can
improve function of heart muscle
after a heart attack [1],
increase insulin secretion from
the pancreas in diabetes [ 2 ],
and heal brain tissue after a
stroke [ 3 ]. Only recently have
there been published studies of
bone and cartilage regeneration
in humans using autologous adult
mesenchymal stem cells.[ 4,5 ].
Currently there is a lot of
confusing information about the
use of stem cells in medicine.
This arises, in large part, from
the fact that while the concept
of using stem cells sounds easy
and appealing, the actual
practice is much more involved.
The result is a lot if
misinformation that sounds
promising at first glance, but
does not make sense when looked
at scientifically. Some
examples are:
1. Pills or drugs to mobilize
stem cells: There are new
supplements claiming to
regenerate every tissue in the
body from muscle to brain to
liver to kidney. The best of
these have actually
had blood samples tested using
Fluorescence
Activated Cell Sorting to
show some increase in
circulating blood stem cells.
The problem? The types of stem
cells mobilized into the blood
stream are cells destined to
produce more blood, not repair
tissues. In particular, one of
the MVP's
of the adult stem cell world (MSC's)
don't circulate in the blood, so
they stay put where they're
located. These supplements might
help if you had anemia, but not
much else.
2. Embryonic stem cell
injections or cord blood
injections: These are stem cells
from someone else injected IV.
Most of this is happening in
third world countries. A few
issues. One question is how
these stem cells were isolated,
as there has been at least one
significant allergic reaction
(which should never happen with
a true stem cell) reported on a
California company offering
embryonic stem cells in Mexico.
Assuming they are stem cells,
the second issue is disease
transmission. First, there are
the common diseases such as HIV,
Hepatitis, and other viral
infections we can detect.
Second, there is the issue of
stem cells being able to
transmit genetic disease such as
an increased risk for
osteoporosis (see earlier post).
Finally, there isn't much data
that shows that if you have a
bum knee, a bad kidney, and
liver spots on your skin, that
these cells will be able to home
to one of these areas to allow
repair. In fact, most studies
show that even in severe injury
models (where a severe life
threatening injury is created
like a heart attack or a lung
injury) direct infusion of cells
to the damaged area results in
more repair than placing the
cells in the blood stream.
3. Adult stem cell injections
IV: I have seen clinics
beginning to use various
marrow concentrate systems to
inject marrow nucleated cells
into the veins (IV). Again, the
issues with IV infusion as
discussed above apply here as
well. The other big issue that
that MSC's make up
about 1 in 50,000 to 1 in
500,000 of these marrow
nucleated cells. This means a
very dilute stem cell population
is actually being
injected. As an example,
50 cc of bone marrow might
contain trillions of cells, but
only less than 0.0002% (in some
older patients) are
actually stem cells
capable of tissue repair.
4. Bone Marrow concentration via
bedside centrifuge: There are
companies advertising systems
(as above) that take whole bone
marrow and magically produce
millions upon millions of stem
cells. Actually,
the stem cells they refer to are
CD34+ heme progenitors (stem
cells that make more blood
products) and not MSC's
which can repair tissue. So the
same issues as above apply
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What About
Safety?
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How
Autologous
Mesenchymal Stem Cells Are Properly Used
The process begins by isolating a
person’s own (Autologous)
Mesenchymal stem cells (MSCs) from a
sample of bone marrow drawn from their
hip. The MSCs then divide
in a natural growth medium that comes
from the same person’s blood platelets.
The result is to take the
relatively small number of MSCs found in
a sample bone marrow, say 2 million, and
expand them to a population of 20 – 50+
million. With these
numbers, substantial tissue growth is
made possible. The MSCs
are then injected with a small needle,
under live x-ray, into areas of bone,
cartilage, and ligament/ tendon damage.
Cartilage can be regrown in generalized
arthritis and/or solitary cartilage defects
in
knees,
shoulders,
ankles,
hips, and fingers. It can
also grow to repair partial meniscus tears,
ligaments and tendon injuries, such as
sprains or partial tears of the ACL, PCL and
MCL of the knee, the rotator cuff and
supporting ligaments of the
shoulder,
ankle and hand/wrist, as well as plantar
fasciitis, golfer’s and tennis elbow, can
also be repaired. Bone can be
re-grown in
chronic non-healing stress fractures or
fractures of larger bones that have not
healed in spite of casting or even surgery.
Chronic conditions such as
avascular necrosis have also been
successfully treated.
Finally, some painful
disc bulges in lumbar spine (low back)
can be corrected to relieve back and leg
pain. People undergoing these
treatments are back on their feet the same
day.
Those undergoing hip, knee, and
ankle injections can begin walking longer
distances after the first week.
Their activity levels are gradually
increased over the following month, with the
expectation that they will be back to their
pre injury activity level after three
months.
References - these are
links directly to the web based abstract or
article
1.
Int J Cardiol.
2008 Jul 19
2.
Stem Cells.
2008 Jan;26(1):244-53. Epub
2007 Oct 11
3. Neuroimage.
2005 Nov 15;28(3):698-707. Epub 2005 Aug 19
Check Out Dr. Busse' Contribution on
Stemcell Doctor Blog
For informational Videos on how stem cells
work and grow Click here
Do you need to know how safe cell are grown?
Click here
FAQ for
Stem Cell Questions
Questions?
Ask The Spinal Injury
Foundation Institutional Review Board
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