Researchers make key memory cells in lab dish

CHICAGO: U.S. researchers have coaxed stem cells into becoming a type of brain cell that dies off early in people with Alzheimer's disease.

The new technology would provide a ready supply of cells for use in testing new drugs or even transplants to help restore lost memory, the team reported on Friday in the journal Stem Cell.

While most Alzheimer's research is done in genetically modified mice, the new technique would allow researchers to study a key aspect of the disease in human cells.

"These are cells that are critically important for memory functions," said Dr. Jack Kessler of Northwestern University Feinberg School of Medicine in Chicago, who worked on the study.

Kessler said the team used embryonic stem cells to create the neurons, which are thought to be among the earliest brain cells lost in Alzheimer's disease.

Stem cells are the body's master cells, the source of all other cells. Embryonic stem cells, taken from days-old human embryos, are especially pliable.

The technique to convert stem cells into neurons was developed by Christopher Bissonnette, a former doctoral student in Kessler's lab, who was inspired by the death of his own grandfather from Alzheimer's disease, a fatal brain-wasting form of dementia that affects memory, thinking and behavior.

When Kessler and Bissonnette implanted the newly grown nerve cells into the brains of mice, they functioned normally, producing nerve fibers called axons and making the brain chemical acetylcholine, used to retrieve memories from other parts of the brain.

The researchers say the technique can produce an almost infinite number of these cells, giving other scientists the chance to study these cells.

ORDINARY SKIN CELLS

The team has used the same approach to make induced pluripotent stem cells, in which ordinary skin cells are reprogrammed into an embryonic-like state. Using these cells, also known as iPS cells, the researchers converted them into brain cells or neurons.

The advantage of iPS cells, Kessler said, is they can be made from people with known Alzheimer's disease, allowing researchers to study differences between healthy cells and diseased cells.

The team made neurons from Alzheimer's patients, healthy people with no family history of Alzheimer's, and people who are healthy but have a genetic predisposition to develop the disease.

"These are real people with real disease. That's why it's exciting," Kessler said.

Kessler said the technology is far from ready, but that eventually it may be possible to make replacement memory cells that can be transplanted into people with Alzheimer's.

"This is exactly the type of fundamental research that is needed," William Thies, chief medical and scientific officer of the Alzheimer's Association, said in an e-mail.

"Knowing more about what causes and prevents brain cell death in Alzheimer's disease will undoubtedly be important for the development of future Alzheimer's treatments."

Write your stress away

CHICAGO: Spending a few minutes before a test to write down their anxieties could help students perform better, researchers report in the journal Science.

Psychologists at the University of Chicago have discovered a quick and easy way for stressed-out students to avoid choking on a high-stakes test: Take a few minutes right before the exam to write about all those fears.

A study published online Thursday by the journal Science found that anxious students given 10 minutes to put their feelings down on paper performed significantly better than their peers who wrote about other topics or did nothing at all.

The idea that there are simple steps to improve test scores — outside of, say, private tutors or SAT prep courses — is sure to be welcome news for students, parents and educators who have long struggled to get students to perform their best on midterms, finals and college entrance exams.

"You don't have to wield these expensive or time-consuming tools," said psychology professor Sian L. Beilock, who conducted the study with graduate student Gerardo Ramirez.

Writing about emotional events had been shown to reduce rumination — which is when people devote mental energy to revisiting distressing ideas — in the clinically depressed, Beilock said. Perhaps writing about one's emotions before an exam would free up that brain power for the task at hand.

The pair performed a series of experiments to test their hypothesis. First, they asked 20 college students to take a math test just to get a base-line score, and simply told them to do their best. Next, to raise the stakes, they told the students that they could receive a monetary award if they got a good grade, and that they were being videotaped.

Before beginning the main test, the researchers asked one group of students to spend 10 minutes writing down their feelings about the test, and the other group sat quietly for that time. Everyone then took the same exam.

The researchers found that students who sat quietly did 12% worse than they had on the pre-test, and the ones who wrote about their anxieties improved their scores by 5%.

They repeated the experiment with three groups of college students: one that wrote about their test-related anxieties, one that sat quietly and a third that was asked to write about an unemotional event unrelated to the test. This time, the group that wrote about their fears improved their scores by 4%, and students in the other two groups saw their scores fall 7%. The results showed that it was writing about anxieties — not the mere act of writing — that made the difference.

Beilock and Ramirez then went to see 106 ninth-grade biology students at a Chicago-area private school six weeks before their final exam and asked the students to rate how anxious they became in testing situations. The researchers found that anxious students who spent 10 minutes writing about their feelings about the final exam earned an average grade of B-plus, compared with the B-minus received by anxious students who were told to write about a topic they thought would not be on the test.

But the coolheaded students didn't see the same bump. The researchers concluded that the writing exercise probably helped put anxious students on more equal footing with their less flappable peers.

"There's something about writing, just putting your vague thoughts and feelings into words, that seems to have a powerful influence," said Akira Miyake, a psychologist at the University of Colorado at Boulder, who was not involved in the study. "This opens up a lot of interesting issues."

But he cautioned against applying the findings too soon: "It's possible someone might start thinking about those negative thoughts over and over, so that might be another issue to be examined."