Posted: May 16, 2014 at 8:43 pm
Dr. Broyles #39; Cartilage Regeneration: Why Bone Marrow Stem Cells?
Dr. Broyles highlights the differences between Dr. Saw #39;s methods and his own, including FDA regulations in the US regarding autologous stem cells. For more information visit - http://www.cartilageregenera...
By: boneandjointclinicbr
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Dr. Broyles' Cartilage Regeneration: Why Bone Marrow Stem Cells? - Video
Posted: May 16, 2014 at 7:48 pm
Dr. Broyles #39; Cartilage Regeneration: Why Bone Marrow Stem Cells?
Dr. Broyles highlights the differences between Dr. Saw #39;s methods and his own, including FDA regulations in the US regarding autologous stem cells. For more information visit - http://www.cartilageregenera...
By: boneandjointclinicbr
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Dr. Broyles' Cartilage Regeneration: Why Bone Marrow Stem Cells? - Video
Posted: May 16, 2014 at 7:48 pm
Concerns that stem cells could cause cancer in recipients are fading further with a new study
New bone formation (stained bright green under ultra-violet light) was seen in monkeys given their own reprogrammed stem cells. Courtesy of Nature magazine
A major concern over using stem cells is the risk of tumors: but now a new study shows that It takes a lot of effort to get induced pluripotent stem (iPS) cells to grow into tumors after they have been transplanted into a monkey. The findings will bolster the prospects of one day using such cells clinically in humans.
Making iPS cells from an animal's own skin cells and then transplanting them back into the creature also does not trigger an inflammatory response as long as the cells have first been coaxed to differentiate towards a more specialized cell type. Both observations, published inCell Reports today, bode well for potential cell therapies.
It's important because the field is very controversial right now, saysAshleigh Boyd,a stem-cell researcher at University College London, who was not involved in the work. It is showing that the weight of evidence is pointing towards the fact that the cells won't be rejected.
Pluripotent stem cells can be differentiated into many different specialized cell types in culture and so are touted for their potential as therapies to replace tissue lost in diseases such as Parkinsons and some forms of diabetes and blindness. iPS cells, which are made by reprogramming adult cells, have an extra advantage because transplants made from them could be genetically matched to the recipient.
Researchers all over the world are pursuing therapies based on iPS cells, and a group in Japan began enrolling patients for a human study last year. But work in mice has suggested controversially that even genetically matched iPS cellscan trigger an immune response, and pluripotent stem cells can also form slow-growing tumors, another safety concern.
Closer to human Cynthia Dunbar, a stem-cell biologist at the National Institutes of Health in Bethesda, Maryland, who led the new study, decided to evaluate both concerns in healthy rhesus macaques. Human stem cells are normally only studied for their ability to form tumors in mice as a test of pluripotency if the animals immune systems are compromised, she says.
We really wanted to set up a model that was closer to human. It was somewhat reassuring that in a normal monkey with a normal immune system you had to give a whole lot of immature cells to get any kind of tumour to grow, and they were very slow growing.
Dunbar and her team made iPS cells from skin and white blood cells from two rhesus macaques, and transplanted the iPS cells back into the monkeys that provided them. It took 20 times as many iPS cells to form a tumor in a monkey, compared with the numbers needed in an immunocompromised mouse. Such information will be valuable for assessing safety risks of potential therapies, Dunbar says. And although the iPS cells did trigger a mild immune response attracting white blood cells and causing local inflammation iPS cells that had first been differentiated to a more mature state did not.
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New Stem Cell Finding Bodes Well for Future Medical Use in Humans
Posted: May 16, 2014 at 7:48 pm
THURSDAY, May 15, 2014 (HealthDay News) -- Although the very concept of cancer stem cells has been controversial, new research provides proof that these distinct types of cells exist in humans.
Using genetic tracking, researchers found that a gene mutation tied to cancer's development can be traced back to cancer stem cells. These cells are at the root of cancer and responsible for supporting the growth and progression of the disease, the scientists report.
Cancer stem cells are able to replenish themselves and produce other types of cancer cells, just as healthy cells produce other normal cells, the study's British and European authors explained.
"It's like having dandelions in your lawn. You can pull out as many as you want, but if you don't get the roots they'll come back," study first author Dr. Petter Woll, of the MRC Weatherall Institute for Molecular Medicine at the University of Oxford, said in a university news release.
The researchers, led by a team of scientists at Oxford and the Karolinska Institute in Sweden, said their findings could have significant implications for cancer treatment. They explained that by targeting cancer stem cells, doctors could not only get rid of a patient's cancer but also prevent any remaining cancer cells from sustaining the disease.
The study, published May 15 in Cancer Cell, involved 15 patients diagnosed with myelodysplastic syndromes (MDS), a type of cancer that often develops into acute myeloid leukemia, a form of blood cancer.
The researchers examined the cancer cells in the patients' bone marrow. Four of the patients were also monitored over time. One patient was followed for two years. Two patients were followed for 30 months and another patient was monitored for 10 years.
According to the researchers, in prior studies citing the existence of cancer stem cells, the lab tests that were used to identify these cells were considered by many to be unreliable.
However, "In our studies we avoided the problem of unreliable lab tests by tracking the origin and development of cancer-driving mutations in MDS patients," explained study leader Sten Eirik Jacobsen, of Oxford's MRC Molecular Haematology Unit and the Weatherall Institute for Molecular Medicine.
According to the research, a distinct group of MDS cells had all the characteristics of cancer stem cells, and only these particular cancer cells appeared able to cause tumor spread.
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Scientists get closer to the stem cells that may drive cancers
Posted: May 16, 2014 at 7:48 pm
Mice crippled by version of MS could walk again after less than two weeks Were previously so disabled they couldn't stand long enough to be fed Researchers say they had not expected the stem cell treatment to work These cells may have worked as they were grown in a crowded lab dish
By Anna Hodgekiss
Published: 03:28 EST, 16 May 2014 | Updated: 03:50 EST, 16 May 2014
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Progress: The brain of someone with MS, which in later stages, can leave patients unable to walk
Stem cells could hold the key to treating people paralysed by multiple sclerosis, landmark research has revealed.
Treatment with human stem cells has allowed mice crippled by a version of MS to walk again after less than two weeks.
Scientists admit to being astonished by the result and believe it opens up a new avenue of research in the quest for solutions to MS.
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Could stem cells help people paralysed by MS? Scientists reveal they are 'astonished' by landmark study
Posted: May 16, 2014 at 7:47 pm
Meet HSCI #39;s Amar Sahay, PhD
Amar Sahay, PhD, is an Assistant Professor at the Center for Regenerative Medicine and the Department of Psychiatry at Massachusetts General Hospital, Harvar...
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Meet HSCI's Amar Sahay, PhD - Video
Posted: May 16, 2014 at 7:47 pm
BioLamina Symposium 2014 Biorelevant Approaches to Regenerative Medicine Cell-Based Assays Part II
Prof. Outi Hovatta explains human embryonic stem cells from the first derivation to clinical grade cells Human embryonic stem cells (hESC) were originally derived using mouse fetal fibroblasts...
By: BioLamina
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BioLamina Symposium 2014 Biorelevant Approaches to Regenerative Medicine & Cell-Based Assays Part II - Video
Posted: May 16, 2014 at 7:47 pm
BioLamina Symposium 2014 Biorelevant Approaches to Regenerative Medicine Cell-Based Assays Part VI
PhD Anna Falk from the Karolinska institute talks about The role of neural stem cells in neurodevelopmental disorders For psychiatric diseases, which later in life manifest in impairment of...
By: BioLamina
Posted: May 15, 2014 at 11:41 pm
Mice have been poked, prodded, injected and dissected in the name of science. But there are limits to what mice can teach us especially when it comes to stem cell therapies. For the first time, researchers haveturned skin cells into bone in a creature more closely related to humans: monkeys.
In a study published Thursday in the journal Cell Reports, scientists report that they regrew bone in 25rhesus macaques using induced pluripotent stem cells (iPSCs) taken from the creatures skin. Since macaques are more closely related to humans, their discovery could help push stem cell therapies into early clinical trials in humans.
While this is the good news, the bad news is that iPSCs can also seed tumors in monkeys; however, the tumors grew at a far slower rate than in previous studies in mice. This finding further emphasizes the key role primates likely will play in testing the safety of potential stem cell therapies.
Repairing Bone
Researchers used a common procedure to reprogram macaque skin cells, and coaxed them into pluripotent cells that were capable of building bone. They seeded these cells into ceramic scaffolds, which are already used by surgeons used to reconstruct bone. The cells took, and the monkeys successfully grew new bone.
In some experiments, the monkeys formed teratomas nasty tumors that can contain teeth and hair when they were injected with undifferentiated iPSCs, or cells that have the potential to change into any kind of cell. However, the tumors grew 20 times slower than in mice, highlighting an important difference between mice and monkeys.
Fortunately, tumors did not form in monkeys that were injected with differentiated iPSCs, or cells that were programmed to createbone cells.
Advancing Research
Researchers say their successful procedure proves that monkeys willplay an important rolein research on therapies using iPSCs. These monkeys will help scientists test and analyze risks associated with the therapies and improve their safety.
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Succssful Stem Cell Therapy in Monkeys is First of Its Kind
Posted: May 15, 2014 at 11:41 pm
Researchers have shown for the first time in an animal that is more closely related to humans that it is possible to make new bone from stem-cell-like induced pluripotent stem cells (iPSCs) made from an individual animal's own skin cells. The study in monkeys reported in the Cell Press journal Cell Reports on May 15th also shows that there is some risk that those iPSCs could seed tumors, but that unfortunate outcome appears to be less likely than studies in immune-compromised mice would suggest.
"We have been able to design an animal model for testing of pluripotent stem cell therapies using the rhesus macaque, a small monkey that is readily available and has been validated as being closely related physiologically to humans," said Cynthia Dunbar of the National Heart, Lung, and Blood Institute. "We have used this model to demonstrate that tumor formation of a type called a 'teratoma' from undifferentiated autologous iPSCs does occur; however, tumor formation is very slow and requires large numbers of iPSCs given under very hospitable conditions. We have also shown that new bone can be produced from autologous iPSCs, as a model for their possible clinical application."
Autologous refers to the fact that the iPSCs capable of producing any tissue typein this case bonewere derived from the very individual that later received them. That means that use of these cells in tissue repair would not require long-term or possibly toxic immune suppression drugs to prevent rejection.
The researchers first used a standard recipe to reprogram skin cells taken from rhesus macaques. They then coaxed those cells to form first pluripotent stem cells and then cells that have the potential to act more specifically as bone progenitors. Those progenitor cells were then seeded onto ceramic scaffolds that are already in use by reconstructive surgeons attempting to fill in or rebuild bone. And, it worked; the monkeys grew new bone.
Importantly, the researchers report that no teratoma structures developed in monkeys that had received the bone "stem cells." In other experiments, undifferentiated iPSCs did form teratomas in a dose-dependent manner.
The researchers say that therapies based on this approach could be particularly beneficial for people with large congenital bone defects or other traumatic injuries. Although bone replacement is an unlikely "first in human" use for stem cell therapies given that the condition it treats is not life threatening, the findings in a primate are an essential step on the path toward regenerative clinical medicine.
"A large animal preclinical model for the development of pluripotent or other high-risk/high-reward generative cell therapies is absolutely required to address issues of tissue integration or homing, risk of tumor formation, and immunogenicity," Dunbar said. "The testing of human-derived cells in vitro or in profoundly immunodeficient mice simply cannot model these crucial preclinical safety and efficiency issues."
The NIH team is now working with collaborators on differentiation of the macaque iPSCs into liver, heart, and white blood cells for eventual clinical trials in hepatitis C, heart failure, and chronic granulomatous disease, respectively.
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The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.
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First test of pluripotent stem cell therapy in monkeys is successful
