Stem cells can improve memory after brain injury

Stem cells can improve memory after brain injury

New UC Irvine research is among the first to demonstrate that neural stem cells may help to restore memory after brain damage.

In the study, mice with brain injuries experienced enhanced memory -- similar to the level found in healthy mice -- up to three months after receiving a stem cell treatment. Scientists believe the stem cells secreted proteins called neurotrophins that protected vulnerable cells from death and rescued memory. This creates hope that a drug to boost production of these proteins could be developed to restore the ability to remember in patients with neuronal loss.

"Our research provides clear evidence that stem cells can reverse memory loss," said Frank LaFerla, professor of neurobiology and behavior at UCI. "This gives us hope that stem cells someday could help restore brain function in humans suffering from a wide range of diseases and injuries that impair memory formation."

The results of the study appear Oct. 31 in the Journal of Neuroscience.

LaFerla, Mathew Blurton-Jones and Tritia Yamasaki performed their experiments using a new type of genetically engineered mouse that develops brain lesions in areas designated by the scientists. For this study, they destroyed cells in the hippocampus, an area of the brain vital to memory formation and where neurons often die.

To test memory, the researchers gave place and object recognition tests to healthy mice and mice with brain injuries. Memories of place depend upon the hippocampus, and memories of objects depend more upon the cortex. In the place test, healthy mice remembered their surroundings about 70 percent of the time, but mice with brain injuries remembered it just 40 percent of the time. In the object test, healthy mice remembered objects about 80 percent of the time, while injured mice remembered as poorly as about 65 percent of the time.

The scientists then set out to learn whether neural stem cells from a mouse could improve memory in mice with brain injuries. To test this, they injected each mouse with about 200,000 neural stem cells that were engineered to appear green under ultraviolet light. The color allows the scientists to track the stem cells inside the mouse brain after transplantation.

Three months after implanting the stem cells, the mice were tested on place recognition. The researchers found that mice with brain injuries that also received stem cells remembered their surroundings about 70 percent of the time - the same level as healthy mice. In contrast, control mice that didn't receive stem cells still had memory impairments.

Next, the scientists took a closer look at how the green-colored stem cells behaved in the mouse brain. They found that only about 4 percent of them turned into neurons, indicating the stem cells were not improving memory simply by replacing the dead brain cells. In the healthy mice, the stem cells migrated throughout the brain, but in the mice with neuronal loss, the cells congregated in the hippocampus, the area of the injury. Interestingly, mice that had been treated with stem cells had more neurons four months after the transplantation than mice that had not been treated.

"We know that very few of the cells are becoming neurons, so we think that the stem cells are instead enhancing the local brain microenvironment," Blurton-Jones said. "We have evidence suggesting that the stem cells provide support to vulnerable and injured neurons, keeping them alive and functional by making beneficial proteins called neurotrophins."

If supplemental neurotrophins are in fact at the root of memory enhancement, scientists could try to create a drug that enhances the release or production of these proteins. Scientists then could spend less time coaxing stem cells to turn into other types of cells, at least as it relates to memory research.

"Much of the focus in stem cell research has been how to turn them into different types of cells such as neurons, but maybe that is not always necessary," Yamasaki said. "In this case, we did not have to make neurons to improve memory."

UCI scientists Debbi Morrissette, Masashi Kitazawa and Salvatore Oddo also worked on this study, which was funded by the National Institute on Aging, the National Institutes of Health, and a California Institute for Regenerative Medicine postdoctoral scholar award.

Technorati : Stem, brain, cells, improve, injury, memory

The Google phone is inching closer to reality

The Google phone: Has a wireless upheaval begun?Questions remain, but analysts expect a Google phone by mid-2008
The Google phone is inching closer to reality, with wireless handhelds running Google Inc. applications and operating software expected in the first half of 2008, several industry analysts said today.
Some see Google's model as revolutionary in the U.S., where nearly all customers buy their cellular phones from a wireless carrier and are locked into a contract with that carrier. But Google's entry could signal a more open system where a customer buys the Google phone and then chooses a carrier, they noted.
The Wall Street Journal today cited unnamed sources and said that Google is expected to announce software within two weeks that would run on hardware from other vendors. The Google phone is expected to be available by mid-2008. The company did not comment.
Last week at the semiannual CTIA show in San Francisco, several analysts said they had heard rumors that Google would be offering software to Taiwan-based device maker High Tech Computer Corp. (HTC) for the Google phone.
Today, Gartner Inc. analysts Phillip Redman said the rumor was still that the Google phone "is coming from HTC for next year, [with] 50,000 devices initially."
HTC could not be reached for immediate comment.
Lewis Ward, an analyst at Framingham, Mass.-based market research company IDC, said Google is clearly working on software for a phone, but after making a presentation at CTIA on emerging markets last week, he said, "It didn't sound like it was on HTC after all."
Unlike several analysts who said that Google could face a fight from carriers opposed to open networks and open devices, Ward and Redman said some carriers will cooperate with Google. "It's possible some carriers will work with Google," Ward said. "AT&T seems to be more open already with its iPhone support and other things, while T-Mobile and Sprint Nextel may be more open than Verizon Wireless."
Redman said that Google's "brand is attractive, so I think there will be takers" for building hardware and for providing network support.
At CTIA, Ward said a Google phone would make a wireless portal out of what Google already provides on a wired network to a PC, such as maps, social networking and even video sharing.
"This is about Google as a portal," Ward said last week. "This is fundamentally about wireless and wire-line converging."
Ward said Google's plans for its phone software are still up in the air. "What's unclear also is whether it will be a Linux free and open [operating system] running on top of the hardware, with applets and widgets and search and all the advanced stuff that Google has done in the past."
Jeffrey Kagan, an independent wireless analyst based in Atlanta, said many questions are raised by Google's proposition, including what the phone could be named. "Will it be a regular phone, or will it be more like the Apple iPhone? How will customers pay for it? Will it be different from the traditional way we use and pay for wireless phones? There are so many questions," Kagan said.
Like Apple Inc. with the iPhone, "Google could be very successful if they crack the code." Kagan added. "The cell phone industry ... is going through enormous change and expansion. Many ideas will be tried. Some will work, and some will fail."

Technorati : Google phone