Category Archives: Stem Cells

Mar. 21, 2013 Cells in the body need to be acutely aware of their surroundings. A signal from one direction may cause a cell to react in a very different way than if it had come from another direction. Unfortunately for researchers, such vital directional cues are lost when cells are removed from their natural environment to grow in an artificial broth of nutrients and growth factors.

Now, researchers at the Stanford University School of Medicine and the Howard Hughes Medical Institute have devised a way to mimic in the laboratory the spatially oriented signaling that cells normally experience.

Using the technique, they've found that the location of a "divide now" signal on the membrane of a human embryonic stem cell governs where in that cell the plane of division occurs. It also determines which of two daughter cells remains a stem cell and which will become a progenitor cell to replace or repair damaged tissue.

The research offers an unprecedented, real-time glimpse into the intimate world of a single stem cell as it decides when and how to divide, and what its daughter cells should become. But the implications stretch beyond stem cells.

"In the body, it is likely that every cell grows and differentiates in some kind of orientation," said Roeland Nusse, PhD, professor of developmental biology. "Without this guidance, specialized cells would end up in the wrong place. Now, we can study the division of single mammalian cells in real time and see them dividing and differentiating in an oriented way."

Understanding this process of self-renewal and specialization (or differentiation) is critical to learning how to truly harness the power of stem cells for future therapies. But polarity, or the ability of a cell to distinguish its top from bottom or left from right, is also vital to many other biological processes. For example, hair grows out of, rather than into, the body, and tissues develop with orderly layers of specific cell types.

Nusse is the senior author of the work, published March 23 in Science. He is also a member of the Stanford Cancer Institute, the Stanford Institute for Stem Cell Biology and Regenerative Medicine and HHMI investigator. Shukry Habib, PhD, a research associate and Siebel Scholar, is the lead author of the work. The study was funded in part by a grant from the California Institute of Regenerative Medicine.

Stem cells are unique in their ability to both self-renew and to generate progenitor cells that can become many cell types. A single stem cell can divide to make two new stem cells or, in a process called asymmetric division, give rise to one stem cell and one progenitor cell. Because the original parent cell is replaced by the two new daughter cells, this approach ensures that stem cells will not be depleted during periods of development or healing.

Things change when these cells are grown in the laboratory, however. Researchers usually choose growth conditions that favor specific outcomes: self-renewal or differentiation into specialized cell types. These growth or differentiation signals affect all parts of the cell equally, and it's not been possible under these conditions to ascertain whether and how the location of these signals may affect the outcome.

In the current study, Habib tested the effect on human embryonic stem cells of a protein called Wnt3a, which is known to play a critical role in embryonic development and in the growth and maintenance of stem cells. The stem cells have many receptors for Wnt proteins on their surfaces, and Wnt3a has been shown to promote self-renewal over differentiation in several types of stem cells.

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Stem cells use signal orientation to guide division, study shows

Public release date: 19-Mar-2013 [ | E-mail | Share ]

Contact: Robert Miranda cogcomm@aol.com Cell Transplantation Center of Excellence for Aging and Brain Repair

Putnam Valley, NY. (Mar. 19 2013) A team of researchers in Seoul, Korea have reported finding evidence that deer antlers - unique in that they regenerate annually - contain multipotent stem cells that could be useful for tissue regeneration in veterinary medicine.

The study appears as an early e-publication for the journal Cell Transplantation, and is now freely available on-line at http://www.ingentaconnect.com/content/cog/ct/pre-prints/ct0897seo.

"We successfully isolated and characterized antler tissue-derived multipotent stem cells and confirmed that the isolated cells are self-renewing and can differentiate into multiple lineages," said study co-author Dr. Kyung-Sun Kang of the College of Veterinary Medicine at Seoul National University. "Using optimized culture conditions, deer antler displayed vigorous cell proliferation."

Deer antler has been an issue in the news recently when professional athletes allegedly therapeutically used deer antler sprays, said to contain the insulin-like growth factor, IGF-1, to recover from injuries. The Korean research team did not investigate the potential for deer antler to be used in human therapies, but suggested that it could be used in veterinary medicine due to the impact of two important factors; the regenerative and the proliferative capabilities of the stem cells they isolated.

Stem cells, cells with the capability to differentiate into varieties of cells, have been isolated from a number of tissues, including bone marrow, fat tissues, umbilical cord blood, placenta and menstrual blood. Stem cell research in the last two decades has focused on both pluripotent stem cells, able to differentiate into all cell types of the body, and multipotent stem cells, able to differentiate into some but not all cell types, the latter of which has a longer history of study as they were identified earlier.

Researchers have sought to use transplanted stem cells for many regenerative purposes from using them to regenerate neural cells following stroke or spinal cord injuries, to using stem cells to help regenerate failing or injured organs.

Deer antler is of interest, said the researchers, "because antlers are very peculiar organs in that they are lost and re-grown annually.a rare example of a completely regenerating organ in mammals."

According to the researchers, they subjected deer antler to differentiation assays for osteogenic (bone), adipogenic (fat) and chondrogenic (cartilage) lineages under culture conditions specific for each lineage to confirm the multi-lineage differentiation ability of antler multipotent stem cells. They concluded that deer antler tissue might be a "valuable source of stem cells" that could "be a potentially useful source of regenerative therapeutics in veterinary science."

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Cell Transplantation study finds stem cells in deer antler

Stem cells that can morph into any type of cell are being tested for their ability to reduce scar tissue and improve the heart's function after a heart attack.

Boston, MA (PRWEB) March 19, 2013

A recent study from Cedars-Sinai Heart Institute in Los Angeles suggests that stem cells may, indeed, heal damaged hearts. The researchers treated 17 heart attack survivors with an infusion of stem cells taken from their own hearts. A year later, the amount of scar tissue had shrunk by about 50%.

These results sound dramatic, but are they an indication that we're getting close to perfecting stem cell therapy? "This is a field where, depending on which investigator you ask, you can get incredibly different answers," says Dr. Richard Lee, professor of medicine at Harvard Medical School and a leading expert on stem cell therapy.

"The field is young. Some studies show only modest or no improvement in heart function, but others have shown dramatically improved function," he says. "We're waiting to see if other doctors can also achieve really good results in other patients."

Studies are producing contradictory results partly because researchers use different methods to harvest and use stem cells. Some are taken from the bone marrow of donors, others from the recipient's own heart. It's not clear which approach works the best.

"Some investigators think this is just a few years away," says Dr. Lee. "And then there are others who feel that there is much more work to be done."

Right now, stem cell therapy is available only to people who participate in a research trial. Anyone who has had a heart attack or who is living with heart failure and wants to take part in a stem cell study can visit http://www.clinicaltrials.gov and search for trials in their area (for example, search "stem cells," "heart," "Los Angeles").

Read the full-length article: "Repairing the heart with stem cells"

Also in the March 2013 issue of the Harvard Women's Health Watch:

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Repairing the Heart with Stem Cells , From the March 2013 Harvard Women's Health Watch

A team of researchers in Seoul, Korea have reported finding evidence that deer antlers - unique in that they regenerate annually - contain multipotent stem cells that could be useful for tissue regeneration in veterinary medicine.

The study appears as an early e-publication for the journal Cell Transplantation, and is now freely available on-line.

"We successfully isolated and characterized antler tissue-derived multipotent stem cells and confirmed that the isolated cells are self-renewing and can differentiate into multiple lineages," said study co-author Dr. Kyung-Sun Kang of the College of Veterinary Medicine at Seoul National University. "Using optimized culture conditions, deer antler displayed vigorous cell proliferation."

Deer antler has been an issue in the news recently when professional athletes allegedly therapeutically used deer antler sprays, said to contain the insulin-like growth factor, IGF-1, to recover from injuries. The Korean research team did not investigate the potential for deer antler to be used in human therapies, but suggested that it could be used in veterinary medicine due to the impact of two important factors; the regenerative and the proliferative capabilities of the stem cells they isolated.

Stem cells, cells with the capability to differentiate into varieties of cells, have been isolated from a number of tissues, including bone marrow, fat tissues, umbilical cord blood, placenta and menstrual blood. Stem cell research in the last two decades has focused on both pluripotent stem cells, able to differentiate into all cell types of the body, and multipotent stem cells, able to differentiate into some but not all cell types, the latter of which has a longer history of study as they were identified earlier.

Researchers have sought to use transplanted stem cells for many regenerative purposes from using them to regenerate neural cells following stroke or spinal cord injuries, to using stem cells to help regenerate failing or injured organs.

Deer antler is of interest, said the researchers, "because antlers are very peculiar organs in that they are lost and re-grown annually.a rare example of a completely regenerating organ in mammals."

According to the researchers, they subjected deer antler to differentiation assays for osteogenic (bone), adipogenic (fat) and chondrogenic (cartilage) lineages under culture conditions specific for each lineage to confirm the multi-lineage differentiation ability of antler multipotent stem cells. They concluded that deer antler tissue might be a "valuable source of stem cells" that could "be a potentially useful source of regenerative therapeutics in veterinary science."

The researchers noted that the development of deer-specific antibodies "is essential to confirm the identification of antler multipotent stem cells".

They specifically noted that injury to wild animals, including deer, might be treated using deer antler derived cells. They also pointed out that studies involving the use of horse stem cells have found clinical application of equine-derived stem cells.

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Study finds stem cells in deer antler

Mar. 15, 2013 Transplantation of mesenchymal stem cells cultivated on the surface of nanofibrous meshes could be a novel therapeutic strategy against post-prostatectomy erectile dysfunction (ED), conclude the authors of a study which is to be presented at the 28th Annual EAU Congress later this week.

The study was conducted by a group of Korean scientists and will be awarded 3rd prize for best abstract in non-oncology research on the opening day of the congress.

During their investigation, the group aimed to examine the differentiation of human mesenchymal stem cells cultivated on the surface of nanofibrous meshes (nano-hMSCs) into neuron-like cells and repair of erectile dysfunction using their transplantation around the injured cavernous nerve (CN) of rats.

"The objectives of the study reflect a very pertinent need in today's urology practice," said the lead author of the investigation Prof. Y.S. Song of Soonchunhyang University School of Medicine in South Korea. "Post-prostatectomy erectile dysfunction results from injury to the cavernous nerve that provides the autonomic input to erectile tissue. It is a common complication after radical prostatectomy which decreases the patient's quality of life."

"Although advances in equipment and surgical techniques reduce this complication, patients still experience erectile dysfunction after radical prostatectomy," he explained.

Treatment of phosphodiesterase 5 inhibitors shows insufficient effectiveness in the treatment of post-prostatectomy ED and it is believed that the transplantation of stem cells cultivated on the surface of nanofibrous meshes can promote cavernous neuronal regeneration and repair erectile dysfunction.

In the course of the study, the synthesised polymer was electrospun in a rotating drum to prepare nanofibrous meshes and hMSCs were prepared and confirmed. Eight week old male Sprague-Dawley rats were divided into 4 groups of 10 each, including sham operation (group 1), CN injury (group 2), hMSCs treatment after CN injury (group 3) and nano-hMSCs treatment after CN injury (group 4). Immediately after the CN injury in group 4, nano-hMSCs encircled the injured CN. Erectile response was assessed by CN stimulation at 2, 4 weeks. Thereafter, penile tissue samples were harvested and examined using morphological analysis and immuno-histochemical stain against nerves (nestin, tubulin III and map2), endothelium (CD31,vWF) and smooth muscle (smooth muscle actin).

The results of the study revealed that at 2, 4 weeks, transplantation of nano-hMSCs increased the expression levels of cavernous neuronal, endothelial and smooth muscle makers more than hMSCs alone.

Additionally, nano-hMSCs increased the neuronal differentiation of mesenchymal stem cells more than hMSCs alone. At 2, 4 weeks, the mean percent collagen area of caversnosum increased following CN injury and recovered after transplantation of nano-hMSCs more than hMSCs alone.

At 2, 4 weeks, the group with CN injury had significantly lower erectile function than the group without CN injury (p<0.05). The group transplanted with hMSCs showed higher erectile function than the sham operation group (p<0.05), whereas the group transplanted with nano-hMSCs showed higher erectile function than the group with hMSCs alone (p<0.05).

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Stem cells transplantation technique has high potential as a novel therapeutic strategy for erectile dysfunction

Durham, NC (PRWEB) March 15, 2013

Bone transplantation is a major strategy for the repair of bone defects. However, reconstruction of the mandible (jawbone) has long been a difficult challenge for oral surgeons at least up to now. A new study in the latest issue of STEM CELLS Translational Medicine shows how stem cells can be used to successfully repair the mandible after a molar extraction and, years later, the new bone is still functioning properly.

Interestingly, the regenerated bone is also hard, rather than the spongy kind normally found in the jaw.

The new study is a follow-up to previous investigations by an international team of researchers in which they discovered that mesenchymal stem cells taken from dental pulp and seeded on a collagen scaffold successfully repaired the mandible bone. In this latest work, they checked on patients who had received the mandible bone grafts three years earlier to assess the stability and quality of the regenerated bone and vessel network.

They found the new bone had normal function and was richly vascularized, although was much more compact than the spongy type normally found in the mandible. The team theorized that, most probably, regeneration of compact bone occurs because grafted dental-pulp stem cells do not follow the local signals of the surrounding spongy bone.

The mandible is constructed from spongey bone on account of its role linked to the presence of teeth and their movements, so regeneration of a compact, rather than a spongy bone type, is difficult to justify physiologically. We concluded, therefore, that grafted dental pulp stem cells do not pursue the local environmental signals emanating from the alveolar bone surrounding the graft site, said Gianpaolo Papaccio, M.D., Ph.D., of the Department of Experimental Medicine at Second University of Naples, Naples, Italy. He led the study team that included colleagues from Second University as well as researchers from Universit Politecnica delle Marche, Ancona, Italy; Universit CB, Lyon; European Synchrotron Radiation Facility, Grenoble, France; and the University of Michigan in the United States.

This must be taken into consideration when grafting stem cells, Dr. Papaccio continued. Their behavior may be quite variable and, consequently, their differentiation fate in some cases may be affected more by their specific origin than by the local signals of the treated area.

Although the bone regenerated at the graft sites is not of the proper type found in the mandible, he added, it does seem to have a positive clinical impact. In fact, it creates steadier mandibles, may well increase implant stability and, additionally, may improve resistance to mechanical, physical, chemical and pharmacological agents.

Dental pulp is an interesting source of ready-to-use stem cells to treat bone defects, said Anthony Atala, M.D., Editor of STEM CELLS Translational Medicine and Director of the Wake Forest Institute for Regenerative Medicine. The finding that these cells regenerate compact bone in the mandible indicates a potential role in the treatment of oral cancer.

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Stem cells produce compact, regenerated bone in mandible transplants

Washington, Mar 16 (ANI): Transplantation of mesenchymal stem cells cultivated on the surface of nanofibrous meshes could be a novel therapeutic strategy against post-prostatectomy erectile dysfunction (ED), researchers have claimed.

The study was conducted by a group of Korean scientists and will be awarded 3rd prize for best abstract in non-oncology research on the opening day of the congress.

During their investigation, the group aimed to examine the differentiation of human mesenchymal stem cells cultivated on the surface of nanofibrous meshes (nano-hMSCs) into neuron-like cells and repair of erectile dysfunction using their transplantation around the injured cavernous nerve (CN) of rats.

"The objectives of the study reflect a very pertinent need in today's urology practice," the lead author of the investigation Prof. Y.S. Song of Soonchunhyang University School of Medicine in South Korea said.

"Post-prostatectomy erectile dysfunction results from injury to the cavernous nerve that provides the autonomic input to erectile tissue. It is a common complication after radical prostatectomy which decreases the patient's quality of life.

"Although advances in equipment and surgical techniques reduce this complication, patients still experience erectile dysfunction after radical prostatectomy," he said.

Treatment of phosphodiesterase 5 inhibitors shows insufficient effectiveness in the treatment of post-prostatectomy ED and it is believed that the transplantation of stem cells cultivated on the surface of nanofibrous meshes can promote cavernous neuronal regeneration and repair erectile dysfunction. (ANI)

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Stem cells transplantation technique could help repair erectile dysfunction