Efficient process using microRNA converts human skin cells into neurons

Posted on 20 May 2013 by Stem Man

The addition of two particular gene snippets to a skin cell’s usual genetic material is enough to turn that cell into a fully functional neuron, report researchers from the Stanford University School of Medicine. The finding, published online July 13 in Nature, is one of just a few recent reports of ways to create human neurons in a lab dish.

The new capability to essentially grow neurons from scratch is a big step for neuroscience research, which has been stymied by the lack of human neurons for study. Unlike skin cells or blood cells, neurons are not something that’s easy for a living human to donate for research.

“A major problem in neurobiology has been the lack of a good human model,” said senior author Gerald Crabtree, MD, professor of pathology and of developmental biology. “Neurons aren’t like blood. They’re not something people want to give up.”

Generating neurons from easily accessible cells, such as skin cells, makes possible new ways to study neuronal development, model disease processes and test treatments.

It also helps advance the effort, still in its infancy, to replace damaged or dead neurons with new ones.

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Adult stem cell: blind can now see

Posted on 20 May 2013 by Stem Man

: Image via Wikipedia

Dozens of people who were blinded or otherwise suffered severe eye damage when they were splashed with caustic chemicals had their sight restored with transplants of their own stem cells — a stunning success for the burgeoning cell-therapy field, Italian researchers reported Wednesday.

The treatment worked completely in 82 of 107 eyes and partially in 14 others, with benefits lasting up to a decade so far. One man whose eyes were severely damaged more than 60 years ago now has near-normal vision.

“This is a roaring success,” said ophthalmologist Dr. Ivan Schwab of the University of California, Davis, who had no role in the study — the longest and largest of its kind.

Stem cell transplants offer hope to the thousands of people worldwide every year who suffer chemical burns on their corneas from heavy-duty cleansers or other substances at work or at home.

The approach would not help people with damage to the optic nerve or macular degeneration, which involves the retina. Nor would it work in people who are completely blind in both eyes, because doctors need at least some healthy tissue that they can transplant.

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Human Neural Stem Cells Restore Memory in Models of Alzheimer’s Disease

Posted on 19 May 2013 by Stem Man

StemCells Inc. announced preclinical data demonstrating that its proprietary human neural stem cells restored memory and enhanced synaptic function in two animal models relevant to Alzheimer’s disease (AD). The data was presented today at the Alzheimer’s Association International Conference 2012 in Vancouver, Canada.

The study results showed that transplanting the cells into a specific region of the brain, the hippocampus, statistically increased memory in two different animal models. The hippocampus is critically important to the control of memory and is severely impacted by the pathology of AD. Specifically, hippocampal synaptic density is reduced in AD and correlates with memory loss. The researchers observed increased synaptic density and improved memory post transplantation. Importantly, these results did not require reduction in beta amyloid or tau that accumulate in the brains of patients with AD and account for the pathological hallmarks of the disease.

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Protecting the future: how plant stem cells guard against genetic damage

Posted on 19 May 2013 by Stem Man

Scientists at the John Innes Centre in Norwich, UK, have shown how plants can protect themselves against genetic damage caused by environmental stresses. The growing tips of plant roots and shoots have an in-built mechanism that, if it detects damage to the DNA, causes the cell to ‘commit suicide’ rather than pass on its defective DNA.

Plants have, at the very tips of their roots and shoots, small populations of stem cells, through which they are able to grow and produce new tissue throughout the plant’s life. These stem cells are the precursors to producing plant tissues and organs. This means that any defect that arises in the stem cell’s genetic code will be passed on and persist irreversibly throughout the life of the plant, which may last thousands of years.

It is therefore critical that there are safeguards that prevent stem cell defects becoming fixed, particularly as the stem cells exist at the growing tips of shoots and roots where they are especially exposed to potentially hazardous environments.

Nick Fulcher and Robert Sablowski, with funding from the Biotechnology and Biological Sciences Research Council (BBSRC), set out to discover what these safeguards could be. By using X-rays and chemicals they were able to induce damage to DNA, and found that stem cells were much more sensitive to DNA damage than other cells. The cells are able to detect the DNA damage, triggering the death of these cells, thus preventing the damaged genetic code becoming fixed in the rest of the plant tissues.

A similar system exists in animal cells, which has been very well investigated, as the failure of this system can lead to cancer. The discovery of a similar, although distinct system in plants is therefore of great interest in the field of plant development, as well as in the efforts of scientists to develop plants better able to cope with environmental stress.

Drought, high salinity and the accumulation of hazardous chemicals in the soil are side-effects of a changing climate, so knowledge of how plants cope with theses stresses is of fundamental importance to agricultural science’s response to climate change. This is one aim of the research carried out by the John Innes Centre, an institute of the BBSRC.

from http://www.jic.ac.uk/corporate/media-and-public/current-releases/sablowskiDNAdamage.htm

No Barriers to Stem Cell Transplantation for Older Patients with Blood Cancers

Posted on 18 May 2013 by Stem Man

Age alone no longer should be considered a defining factor when determining whether an older patient with blood cancer is a candidate for stem cell transplantation. That’s the conclusion of the first study summarizing long-term outcomes from a series of prospective clinical trials of patients age 60 and over who were treated with the mini-transplant, a “kinder, gentler” form of allogeneic (donor cell) stem cell transplantation developed at Fred Hutchinson Cancer Research Center. The findings are published Nov. 2 in JAMA, The Journal of the American Medical Association.

“Age is no longer a barrier to allogeneic transplant,” said Mohamed Sorror, M.D., M.Sc., an assistant member of the Hutchinson Center’s Clinical Research Division and corresponding author of the paper.

Sorror and colleagues found that the five-year rates of overall and disease-progression-free survival among mini-transplant patients were 35 percent and 32 percent, respectively. Patients in three age groups – 60 to 64, 65 to 69 and 70 to 75 – had comparable survival rates, which suggested that age played a limited role in how patients tolerate the mini-transplant. Increased medical problems unrelated to cancer (comorbidities) and a higher degree of cancer aggressiveness were the two factors that affected survival among those older patients. For example, patients who had less-aggressive cancer and fewer comorbidities had a five-year survival rate of 69 percent, while patients with more aggressive cancer and a significant number of comorbidities had a survival rate of 23 percent, regardless of age.Although a long-term survival rate of one-third of patients may seem low, these patients all would have died of their diseases within a matter of months without a transplant. “The majority of patients were referred for a transplant after they had exhausted all forms of conventional therapy,” said Sorror, who works in the research group led by Rainer Storb, M.D., who developed the mini-transplant.

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