“Latest Stem Cells News”

CHICAGO (Reuters) – A new understanding of the genes that make muscle cells may change the way researchers think about stem cell transplants for muscular dystrophy and muscle injuries, U.S. researchers said on Wednesday.

In a surprise finding, they said genes important for forming muscle cells in embryos and newborns are not normally active in adult stem cells.
And researchers hoping to use muscle stem cells in stem-cell transplant therapies should not assume genes that control early muscle development serve the same purpose in repairing adult muscle, Christoph Lepper and colleagues at the Carnegie Institution in Baltimore reported in the journal Nature.

Earlier studies have shown that two genes — Pax3 and Pax7 — control cells that give rise muscle in embryos, and Pax7 also helps build muscle in newborn mice.
To get a better understanding of their function, Lepper and colleagues studied these genes at various stages of development in live mice.

“I thought that if they are so important in the embryo, they must be important for adult muscle stem cells,” Lepper said in a statement.
The team used genetic engineering to suppress both the Pax3 and Pax7 genes in adult muscle stem cells, and they found that adult stem cells were still able to function normally.

“I was totally surprised to find that the muscle stem cells are normal without them,” Lepper said
The researchers then looked at whether the same was true in injured muscles, when muscle stem cells go to work making new muscle tissue.

To study this, they injured mouse leg muscles between the knee and ankle, and found the muscle stem cells were able to make new muscle, even without the two key embryonic muscle stem cell genes.
The team said the embryonic muscle cell genes appear to only be active in mice within the first three weeks after birth. After that, they believe the genes go quiet and allow a different set of genes to take over.

Finding those genes will be important as scientists pursue new treatments for diseases like muscular dystrophy, a genetic, degenerative disease that affects voluntary muscles, they said.
And they said teams should look at other types of stem cells to see how age might affect their properties, and they should take age of stem cells into account in transplant-based treatments.

from Reuters

Scientists at the Ottawa Hospital Research Institute (OHRI) and the University of Ottawa have discovered a powerful new way to stimulate muscle regeneration, paving the way for new treatments for debilitating conditions such as muscular dystrophy.

The research, to be published in the June 5 issue of Cell Stem Cell, shows for the first time that a protein called Wnt7a increases the number of stem cells in muscle tissue, leading to accelerated growth and repair of skeletal muscle.

“This discovery shows us that by targeting stem cells to boost their numbers, we can improve the body’s ability to repair muscle tissue,” said senior author Dr. Michael Rudnicki. Dr. Rudnicki is the Scientific Director of Canada’s Stem Cell Network and a Senior Scientist at OHRI and Director of OHRI’s Sprott Centre for Stem Cell Research, as well as a Professor of Medicine at the University of Ottawa.

Stem cells give rise to every tissue and organ in the body. Satellite stem cells are specialized muscle stem cells that live in adult skeletal muscle tissue and have the ability to both replicate and differentiate into various types of muscle cells. Dr. Rudnicki’s team found that the Wnt7a protein, when introduced into mouse muscle tissue, significantly increased the population of these satellite stem cells and fueled the regeneration process, creating bigger and stronger muscles. Muscle tissue mass was increased by nearly 20 per cent in the study.

“Our findings point the way to the development of new therapeutic treatment for muscular diseases such as muscular dystrophy, sarcopenia and muscle wasting conditions resulting from extended hospital stays and surgeries,” said Dr. Rudnicki.

from physorg

In a genetic engineering breakthrough that could help everyone from bed-ridden patients to elite athletes, a team of American researchers—including 2007 Nobel Prize winner Mario R. Capecchi—have created a “switch” that allows mutations or light signals to be turned on in muscle stem cells to monitor muscle regeneration in a living mammal. For humans, this work could lead to a genetic switch, or drug, that allows people to grow new muscle cells to replace those that are damaged, worn out, or not working for other reasons (e.g., muscular dystrophy). In addition, this same discovery also gives researchers a new tool for the study of difficult-to-treat muscle cancers. The full report containing details of this advance is available online in The FASEB Journal.

Scientists have made a breakthrough in stem cell research which raises the prospect of regrowing damaged sections of a person’s liver, pancreas or even their brain.
Researchers at the University of NSW have found a way to improve the lifespan and competitiveness of stem cells, overcoming a problem which otherwise saw their regenerative powers fade in about an hour.

Adult stem cells were given a gene to make them resistant to chemotherapy, handing them an “advantage” when used to treat damaged tissue in conjunction with the cancer-fighting treatment.
University of NSW Professor Peter Gunning said as the chemotherapy cleaned out damaged cells, resistant stem cells were left behind to complete their amazing process of turning into healthy replacements thereby restoring the tissue.

“What has been the realm of science fiction is looking more and more like the medicine of the future,” Prof Gunning said.
“The beauty of this technique is that chemotherapy makes space for stem cells coming into muscle and also gives the stem cells an advantage over the locals.

Douglas A. Melton

Scientists have created stem cells from patients suffering from 10 incurable diseases, from Down syndrome to diabetes and Parkinson’s – immortal cells that might one day be turned into repair material for wasting muscles or damaged brains.
The Harvard University-led team has taken skin and bone marrow cells from diseased patients and re-programmed those cells to behave like cells from days-old embryos.

The feat allows scientists for the first time to watch muscular dystrophy and other diseases unfold in a petri dish, “that is, to watch what goes right or wrong,” said Doug Melton, co-director of the Harvard Stem Cell Institute. The cells will also allow researchers to screen new drugs to treat the diseases.
“In these complex genetic diseases, we’re so ignorant at the moment we don’t even know when a patient gets diabetes if they all get it the same way,” Melton said. “There could be 50 different ways to get Type 1 diabetes.” The stem cell lines could help researchers hone in on exactly which mutations are responsible and find “the weak point where you could try to prevent, or treat it.”
“We have good reason to believe that this will make it possible to find new treatments, and eventually drugs, to slow or even stop the course of a number of diseases,” Melton said.
The new cells are “pluripotent” cells that can be coaxed into making any tissue in the human body, and can grow forever.