The Promise of Adult Stem Cells
Adult stem cell science has been making waves lately, thanks to recent headlines about 'major breakthroughs' and high-profile supporters like Rick Perry and Suzanne Somers. Does the research live up to the hype?
FRIDAY, Dec. 16, 2011 - Stem cell research is
one of the most talked-about fields in modern medication. It’s also one of the
most misinterpreted. Many people associate it with only embryonic stem cells,
which are a source of much ethical debate, but there’s actually an complete
world of data and inquiry that includes adult stem cells, which can be found in
our own bodies and may hold the key to treating some significant health conditions.
Recent headlines, for example, have touted “major
breakthroughs” in adult stem cell science and cardiovascular disease, and a
number of high-profile celebrities, politicians,
and athletes have undergone experimental stem cell treatments for pain and
nerve damage. As more and more people seek out information about these
procedures, here’s what you need to know.
Embryonic Stem Cells vs. Adult Stem Cells
Compared with the field of embryonic stem cell research,
adult stem cell research is relatively new territory. For a long period time,
the medical community was interested primarily in embryonic stem cells, which
are pluripotent, meaning they have the possible to generate any one of the 200
other cell types in the human body. Recent research has suggested that some
types of stem cells may be able to transform into other cells via a process
called Trans differentiation, but data - and scientific opinion - is mixed on
this point. Adult stem cells, conversely, are thought to be limited to forming
types of cells based on their tissue of origin. For example, hematopoietic stem
cells, found in bone marrow, give rise to blood cells, while adipose-derived
stem cells, found in fat, give rise to adipocyte (fat) cells.
For one thing, Kohn says, there may be less risk of
rejection with adult stem cells, since they’re often autologous, meaning they
come from a person’s own body
Stem Cell Procedures in the News
Most recently, actress Suzanne Somers revealed that
she had undergone a new stem cell treatment to regrow her right breast after
losing most of it to cancer more than a decade ago. Somers’ procedure, unlike
others mentioned here, was part of an approved clinical trial and involved
injecting stem cell-enriched fat into her breast to replace the damaged tissue.
You can learn more about her treatment here.
Caplan’s worry that high-profile procedures like Perry’s
send the wrong message to patients is a concern shared by many in the stem cell
research community. “When a highly visible celebrity/athlete chooses to undergo
an untested/unproven therapy, and if they happen to get better without knowing
whether the therapy is what caused the improvement, they encourage many other
people to ignore scientific evidence and to substitute hope and blind trust for
proof,” said Lawrence Goldstein, PhD, director of the University of
California-San Diego Stem Cell Program, in an e-mail to ABCNews.com. “The
downside is that many people might be hurt by subjecting themselves to a risky
procedure, or a procedure with unknown risks, when there is no evidence of
benefit to be gained.”
The Current and Future State of Adult
Stem Cell Research
More research is needed, but if future studies can build on
these results, stem cells may revolutionize our ability to treat heart disease,
which is currently the No. 1 killer of both men and women in the United States.
In situations where an autologous transplant is not possible
or has already been done, doctors may use cells from a donor whose tissue type
matches the patient’s. This is riskier, because of the chance of rejection, but
it’s not uncommon.
In most cases, Kohn notes, the stem cells used are
autologous (your own). Doctors extract them from your blood or bone marrow
prior to administering the chemo, freeze them, and then reinject them into your
bloodstream after treatment. Over time, they return to the bone, replacing the
marrow and generating new blood cells.
Heartening Progress Against
Cardiovascular Disease
Researchers at Cedars Sinai Medical Center in Los Angeles
saw similarly promising results when they gave stem cell transplants to 17
people who had experienced major heart attacks about six weeks earlier. After
the surgery, the patients’ scar tissue retreated between 30 and 47 percent, and
recipients regrew the equivalent of 600 million new heart cells - more than
half of the billion that are typically destroyed by a major cardiac event.
In many cases, however - such as those in which the cancer
comes back after a period of remission or is initially unresponsive to
treatment - patients may require high-dose chemo, which destroys not only the
cancer cells but also some of the individual’s healthy cells.
In one such study, at the University of Louisville’s Jewish
Hospital, 16 patients with serious heart damage received a purified infusion of
their own cardiac stem cells. Within a year, their heart function had improved
significantly, from an average LVEF (left ventricle ejection fraction) score of
30.3 percent to an average LVEF score of 42.5 percent. (Less than 40 percent is
considered severe heart failure.)
Other Stem Cell Research on the Horizon
Other research is ongoing in orthopedic surgery, spinal cord
injuries, and even baldness, so in the future, stem cells may be used routinely
to replace hips, repair nerves, or regrow hair. For now, though, experts say we
should be cautiously hopeful.
Blindness: Last year, Italian researchers from
the University of Modena's Centre for Regenerative Medicine reported that they
had used stem cells to successfully restore vision in patients who had been blinded
or left with severely impaired sight due to chemical burns. In the study,
reported in the New England Journal of Medicine, the scientists
extracted stem cells from the limbus of the patients’ healthy eyes and then
grew them into a thin sheet, which was then grafted to the damaged eye to
create a regenerating cornea. Other research has shown similar promise using
healthy cells from a donor’s eye.
Neurological disorders: Researchers are hard at
work on experiments involving stem cells as a treatment for neurodegenerative
disorders such as Alzheimer’s disease and Parkinson’s. Recently, scientists at
the University of Edinburgh and University College London were able to generate
brain nerve cells using skin stem cells from a patient with progressive
Parkinson’s, which they hope will allow them to develop and monitor new drugs
to halt or reverse the condition.
There are also studies trying to actually put new nerve
cells into the brain, Kohn explains. Many of these trials involve embryonic
cells, but at least a few have used induced pluripotent stem cells, which are
adult cells that have been genetically modified to mimic the abilities of
embryonic cells. As with many of these other procedures, however, research is
only just beginning. Much of the evidence that has been gathered thus far is
from animal studies.
FRIDAY, Dec. 16, 2011 - Stem cell research is
one of the most talked-about fields in modern medication. It’s also one of the
most misinterpreted. Many people associate it with only embryonic stem cells,
which are a source of much ethical debate, but there’s actually an complete
world of data and inquiry that includes adult stem cells, which can be found in
our own bodies and may hold the key to treating some significant health conditions.
Recent headlines, for example, have touted “major
breakthroughs” in adult stem cell science and cardiovascular disease, and a
number of high-profile celebrities, politicians,
and athletes have undergone experimental stem cell treatments for pain and
nerve damage. As more and more people seek out information about these
procedures, here’s what you need to know.
Embryonic Stem Cells vs. Adult Stem Cells
Compared with the field of embryonic stem cell research,
adult stem cell research is relatively new territory. For a long period time,
the medical community was interested primarily in embryonic stem cells, which
are pluripotent, meaning they have the possible to generate any one of the 200
other cell types in the human body. Recent research has suggested that some
types of stem cells may be able to transform into other cells via a process
called Trans differentiation, but data - and scientific opinion - is mixed on
this point. Adult stem cells, conversely, are thought to be limited to forming
types of cells based on their tissue of origin. For example, hematopoietic stem
cells, found in bone marrow, give rise to blood cells, while adipose-derived
stem cells, found in fat, give rise to adipocyte (fat) cells.
For one thing, Kohn says, there may be less risk of
rejection with adult stem cells, since they’re often autologous, meaning they
come from a person’s own body
In current years, however, scientists have shifted some of
the focus to adult stem cells, partly out of necessity - federal and state
legislation restricts funding for projects involving the creation, treatment,
or destruction of embryos for research purposes - and partly because of new
discoveries about the benefits of adult cells. . “Embryonic stem cells don’t
match your patient,” he explains. There’s a risk, as with any transplant, that
the body won’t accept them.
Stem Cell Procedures in the News
Which is not to say, however, that adult stem cell research
is immune to controversy.
Earlier this year, in July, Texas governor and Republican
presidential hopeful Rick Perry raised some eyebrows - and red flags - when he
underwent an experimental stem cell procedure to fuse part of his spine. The
treatment, which was done outside of an approved clinical trial, involved lip
suctioning fat from Perry’s body, separating and re-growing the stem cells from
that fat, and then reinjecting the cells into Perry’s back and bloodstream in
the hopes that they would form bone or cartilage. At the time, experts in the
field balked at Perry’s decision to have the procedure, saying there was no
scientific evidence to support its effectiveness - or, more importantly, its
safety - and that by choosing to pursue an untested treatment, the politician
risked blood clots, infection, even cancer cell growth.
Most recently, actress Suzanne Somers revealed that
she had undergone a new stem cell treatment to regrow her right breast after
losing most of it to cancer more than a decade ago. Somers’ procedure, unlike
others mentioned here, was part of an approved clinical trial and involved
injecting stem cell-enriched fat into her breast to replace the damaged tissue.
You can learn more about her treatment here.
Caplan’s worry that high-profile procedures like Perry’s
send the wrong message to patients is a concern shared by many in the stem cell
research community. “When a highly visible celebrity/athlete chooses to undergo
an untested/unproven therapy, and if they happen to get better without knowing
whether the therapy is what caused the improvement, they encourage many other
people to ignore scientific evidence and to substitute hope and blind trust for
proof,” said Lawrence Goldstein, PhD, director of the University of
California-San Diego Stem Cell Program, in an e-mail to ABCNews.com. “The
downside is that many people might be hurt by subjecting themselves to a risky
procedure, or a procedure with unknown risks, when there is no evidence of
benefit to be gained.”
The Current and Future State of Adult
Stem Cell Research
Of course, not all stem cell procedures are as polarizing as
those performed on Perry and Manning. Bone marrow stem cell transplants, using
hematopoietic (blood) cells, have actually been used for decades - since about
1970 - as a treatment for certain genetic diseases and cancers, namely those
affecting the blood, bone marrow, and lymphatic system. In fact, Everyday
Health television show host and former Survivor winner Ethan Zohn had one in
2009 after he was diagnosed with and treated for a rare form of Hodgkin lymphoma.
Standard first line of treatment for both leukemia and lymphoma depends on a
variety of factors but generally includes some amount of chemotherapy with or
without radiation and/or surgery. In many cases, however - such as those in
which the cancer comes back after a period of remission or is initially
unresponsive to treatment - patients may require high-dose chemo, which
destroys not only the cancer cells but also some of the individual’s healthy
cells.
More research is needed, but if future studies can build on
these results, stem cells may revolutionize our ability to treat heart disease,
which is currently the No. 1 killer of both men and women in the United States.
In situations where an autologous transplant is not possible
or has already been done, doctors may use cells from a donor whose tissue type
matches the patient’s. This is riskier, because of the chance of rejection, but
it’s not uncommon.
In most cases, Kohn notes, the stem cells used are
autologous (your own). Doctors extract them from your blood or bone marrow
prior to administering the chemo, freeze them, and then reinject them into your
bloodstream after treatment. Over time, they return to the bone, replacing the
marrow and generating new blood cells.
Heartening Progress Against
Cardiovascular Disease
One of the biggest areas of interest involving adult stem
cells is improving heart function after a major cardiac event such as a heart
attack. Researchers all over the world - including many in the United States -
have been conducting trials for years to test whether stem cell therapy can
reverse heart damage or regrow new heart tissue.
Researchers at Cedars Sinai Medical Center in Los Angeles
saw similarly promising results when they gave stem cell transplants to 17
people who had experienced major heart attacks about six weeks earlier. After
the surgery, the patients’ scar tissue retreated between 30 and 47 percent, and
recipients regrew the equivalent of 600 million new heart cells - more than
half of the billion that are typically destroyed by a major cardiac event.
In many cases, however - such as those in which the cancer
comes back after a period of remission or is initially unresponsive to
treatment - patients may require high-dose chemo, which destroys not only the
cancer cells but also some of the individual’s healthy cells.
In one such study, at the University of Louisville’s Jewish
Hospital, 16 patients with serious heart damage received a purified infusion of
their own cardiac stem cells. Within a year, their heart function had improved
significantly, from an average LVEF (left ventricle ejection fraction) score of
30.3 percent to an average LVEF score of 42.5 percent. (Less than 40 percent is
considered severe heart failure.)
Other Stem Cell Research on the Horizon
Kohn cautions that most research involving adult stem cells,
like that for cardiovascular disease, is still in the early stages, so it could
be a long time - probably five to 10 years, he thinks - before regular patients
have access to stem cell procedures as part of their standard care. “But it’s
exciting,” he says. Among the many health conditions scientists hope to reverse
or cure with stem cells are:
Diabetes: “In the future, what we’d like to be
able to do is grow new pancreas cells to treat diabetes,” Kohn says, noting
that a breakthrough like that could change millions of lives. Indeed, according
to the National Institutes of Health, diabetes affects more people and causes
more deaths each year - about 200,000 - than breast cancer and AIDS combined.
Healthy people have about a million functioning islets, or
clusters, in their pancreas, each comprised of about 1,000 beta cells that help
regulate and produce the insulin necessary for your body to function. In type 1
diabetes, however, those islets are destroyed. Restoring the islet cells to the
pancreas could cure the disease.
Other research is ongoing in orthopedic surgery, spinal cord
injuries, and even baldness, so in the future, stem cells may be used routinely
to replace hips, repair nerves, or regrow hair. For now, though, experts say we
should be cautiously hopeful.
Scientists have been successful with islet transplants in
the past, but mostly using donor cells from cadavers, which are both hard to
come by and require the recipients of the cells to take immunotherapy drugs for
the rest of their lives, putting them at risk for a host of other diseases.
Some research with embryonic stem cells has shown promise in addressing these
complications, but recently, doctors have also been looking at the possibility
of manipulating the patient’s own stem cells to either produce beta cells or
create an entirely new immune system that doesn’t destroy the islets in the
first place.
Blindness: Last year, Italian researchers from
the University of Modena's Centre for Regenerative Medicine reported that they
had used stem cells to successfully restore vision in patients who had been blinded
or left with severely impaired sight due to chemical burns. In the study,
reported in the New England Journal of Medicine, the scientists
extracted stem cells from the limbus of the patients’ healthy eyes and then
grew them into a thin sheet, which was then grafted to the damaged eye to
create a regenerating cornea. Other research has shown similar promise using
healthy cells from a donor’s eye.
Neurological disorders: Researchers are hard at
work on experiments involving stem cells as a treatment for neurodegenerative
disorders such as Alzheimer’s disease and Parkinson’s. Recently, scientists at
the University of Edinburgh and University College London were able to generate
brain nerve cells using skin stem cells from a patient with progressive
Parkinson’s, which they hope will allow them to develop and monitor new drugs
to halt or reverse the condition.
There are also studies trying to actually put new nerve
cells into the brain, Kohn explains. Many of these trials involve embryonic
cells, but at least a few have used induced pluripotent stem cells, which are
adult cells that have been genetically modified to mimic the abilities of
embryonic cells. As with many of these other procedures, however, research is
only just beginning. Much of the evidence that has been gathered thus far is
from animal studies.
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