Researchers rejuvenate stem cell population from elderly mice, enabling muscle recovery

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PUBLIC RELEASE DATE:

16-Feb-2014

Contact: Krista Conger kristac@stanford.edu 650-725-5371 Stanford University Medical Center

STANFORD, Calif. Researchers at the Stanford University School of Medicine have pinpointed why normal aging is accompanied by a diminished ability to regain strength and mobility after muscle injury: Over time, stem cells within muscle tissues dedicated to repairing damage become less able to generate new muscle fibers and struggle to self-renew.

"In the past, it's been thought that muscle stem cells themselves don't change with age, and that any loss of function is primarily due to external factors in the cells' environment," said Helen Blau, PhD, the Donald and Delia B. Baxter Foundation Professor. "However, when we isolated stem cells from older mice, we found that they exhibit profound changes with age. In fact, two-thirds of the cells are dysfunctional when compared to those from younger mice, and the defect persists even when transplanted into young muscles."

Blau and her colleagues also identified for the first time a process by which the older muscle stem cell populations can be rejuvenated to function like younger cells. "Our findings identify a defect inherent to old muscle stem cells," she said. "Most exciting is that we also discovered a way to overcome the defect. As a result, we have a new therapeutic target that could one day be used to help elderly human patients repair muscle damage."

Blau, a professor of microbiology and immunology and director of Stanford's Baxter Laboratory for Stem Cell Biology, is the senior author of a paper describing the research, which will be published online Feb. 16 in Nature Medicine. Postdoctoral scholar Benjamin Cosgrove, PhD, and former postdoctoral scholar Penney Gilbert, PhD, now an assistant professor at the University of Toronto, are the lead authors.

The researchers found that many muscle stem cells isolated from mice that were 2 years old, equivalent to about 80 years of human life, exhibited elevated levels of activity in a biological cascade called the p38 MAP kinase pathway. This pathway impedes the proliferation of the stem cells and encourages them to instead become non-stem, muscle progenitor cells. As a result, although many of the old stem cells divide in a dish, the resulting colonies are very small and do not contain many stem cells.

Using a drug to block this p38 MAP kinase pathway in old stem cells (while also growing them on a specialized matrix called hydrogel) allowed them to divide rapidly in the laboratory and make a large number of potent new stem cells that can robustly repair muscle damage, Blau said.

"Aging is a stochastic but cumulative process," Cosgrove said. "We've now shown that muscle stem cells progressively lose their stem cell function during aging. This treatment does not turn the clock back on dysfunctional stem cells in the aged population. Rather, it stimulates stem cells from old muscle tissues that are still functional to begin dividing and self-renew."

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Researchers rejuvenate stem cell population from elderly mice, enabling muscle recovery

Over 5,000 Cubans receive stem cell treatment: Expert

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Havana, Feb 16 (IANS): More than 5,000 patients have received stem cell treatment in Cuba since its procedure was introduced in 2004, a medical expert said.

Porfirio Hernandez, researcher and vice director at the Hematology and Immunology Institute in Cuba, said the stem cell treatment method has been implemented in 13 of the 15 provinces in Cuba.

As a widely acknowledged pioneer of this practice, Hernandez said that more than 60 percent of patients receiving the treatment had suffered from severe ischemia at lower limbs and other blood vessel related ailments, reported Xinhua.

The therapy has also been used to reduce the sufferings of patients with severe orthopedic and cardiac problems, Hernandez added.

Stem cells are capable of self-renewing, regenerating tissues damaged by diverse disease, traumas, and ageing, and stimulating the creation of new blood vessels.

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Over 5,000 Cubans receive stem cell treatment: Expert

Let’s Play Space Engineers – Episode 84: Space Station Project Part 14 – Video

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Let #39;s Play Space Engineers - Episode 84: Space Station Project Part 14
On this episode of Space Engineers, we continue the Space Station Project. This is kind of a multi-part episode. First we work on the lighting in the lounge/...

By: Sleepless Knights Studios

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Let's Play Space Engineers - Episode 84: Space Station Project Part 14 - Video

Red Knights win first sectional game in 8 years

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MORRISTOWN - To some teams, a first-round playoff game is just a bump on the road toward a district, regional or even a state title.

To the Toronto girls basketball team, the first game was a hurdle that hadn't been cleared in eight years.

On Saturday at Union Local, the Red Knights took a strong leap over the daunting barrier with a 54-51 win over Bellaire St. John in the opening sectional game of the Division IV tournament.

Matthew Peaslee DEFENSE Torontos Malaysia Harrison defends St. John Centrals Marissa Rose during Saturdays Division IV?sectional game at Union Local.

"We came in and knew we had to do something to change the history of our school," said point guard Lexie Berger. "The only way to do that was to win this sectional game."

The Red Knights (12-10) previously topped the Fighting Irish twice in the regular season.

"It's very hard to beat a team three times," said Toronto coach Mallory Blanton said. "That's another goal we had."

Toronto 54, St. John 51

Toronto 13 19 8 14 54

St. John 8 5 19 19 51

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Red Knights win first sectional game in 8 years