Stress study offers clues for new antidepressant drugs

LONDON (Reuters) - Scientists have worked out the way in which stress hormones reduce the number of new brain cells - a process linked to depression - and say their work should help researchers develop more effective antidepressants.

The scientists identified a protein largely responsible for the long-term detrimental effect of stress on cells.

They also successfully used an experimental drug compound to block this effect, pointing to a possible way of developing new antidepressants, the study published in the Proceedings of the National Academy of Sciences said.

Major depression affects about 20 percent of people at some time in their lives. The World Health Organization (WHO) predicts that by 2020, depression will rival heart disease as the health disorder with the highest global disease burden.

Treatment for depression involves either medication or counseling - and often a combination of both.

But while there are many antidepressants on the market, including top sellers such as Prozac and Seroxat, it is widely accepted that many antidepressants work in only half of patients half of the time, and drugmakers are struggling to come up with a new generation of drugs.

Depression is linked to changes in a process called neurogenesis - the ability of the adult brain to continue producing new brain cells.

At a molecular level, stress is known to increase levels of a hormone called cortisol, which in turn acts on a receptor called the glucocorticoid receptor. But the exact mechanism behind this process has been unclear.

A team under Carmine Pariante of King's College London's Institute of Psychiatry, who led the research, studied human hippocampal stem cells - source of new cells in the human brain.

They gave the cells cortisol to measure the effect on neurogenesis and found that a protein called SGK1 was important in mediating the effects.

By measuring the effect of cortisol over time, they found that increased levels of SGK1 prolong the damaging impact of stress hormones on neurogenesis.

Next, the researchers used an experimental drug compound known to inhibit SGK1 and found it blocked the negative effects of stress hormones, leading to an increase in new brain cells.

The team confirmed the results by studying levels of SGK1 in animals and then in blood samples from people with depression.

(Editing by Louise Ireland)

Paveikslėlis: http://www.sailorspouse.com/spotting-signs-of-depression/

Reguliarus aspirino vartojimas didina apakimo riziką?

Nacionalinė Medikų Asociacija paskelbė 2013-01-25 00:28

Reuters Health. Vartojant nors vieną aspirino tabletę per savaitę, didėja su amžiumi susijusio apakimo rizika. Europoje atlikto tyrimo duomenimis, vartojantys kasdien aspiriną turi du kartus didesnę išsivystyti makulos degeneracijai nei nevartojantys aspirino. Plačiau...

Regular aspirin use tied to age-related vision loss

NEW YORK (Reuters Health) - Taking at least one aspirin every week is linked to the development of age-related vision loss, according to a new study.

The Australian researchers, however, caution that there's still not enough evidence to say taking the popular pain reliever leads to age-related macular degeneration, which is the leading cause of blindness in older people.

"I don't think the current evidence is strong enough to conclude cause. We still need to accumulate more evidence," said Jie Jin Wang, the study's lead author from the University of Sydney.

Currently, over 100 billion aspirin tablets are consumed every year, Wang and her colleagues write in JAMA Internal Medicine. They add that it's commonly used in the prevention of heart attacks or strokes.

In 2011, a European study found seniors who take a daily aspirin were twice as likely to develop vision loss, compared to those who did not (see Reuters Health article of September 30, 2011 here: http://reut.rs/Tmi8Er.)

Wang told Reuters Health that her team saw that 2011 report and wanted to confirm its findings by using information it had collected on a group of Australians over a 15-year period.

Overall, Wang and her colleagues had information on 2,389 people who were over 45 years old. Of those, 257 said they took at least one aspirin every week.

At the end of the study, 63 people had developed so-called wet macular degeneration - the most severe form.

The researchers found 5.8 percent of regular aspirin users ended up with wet macular degeneration, compared to 2.3 percent of people who did not regularly take aspirin.

That difference remained even when the researchers accounted for the participants' age, sex, weight, blood pressure, history of smoking and heart disease.

'CAUTIONARY NOTE'

In a commentary published with the new study, Drs. Sanjay Kaul and George Diamond caution that the study had limitations and previous studies found mixed results when looking at aspirin use and vision loss.

They write that the evidence is not convincing enough for doctors to change how they prescribe aspirin, especially with its benefits in preventing heart attacks and strokes.

"In the final analysis, decisions about aspirin use are best made by balancing the risks against the benefit in context of each individual's medical history and value judgments," they write.

Wang agreed that the findings are not strong enough to support a change in clinical practice, but she said some doctors may want to keep a closer watch on patients at high risk for macular degeneration who are also using aspirin.

Dr. Jack Cioffi, chair of Columbia University Medical Center's department of ophthalmology in New York, agreed with the commentary and said people should stay on aspirin if their doctors have them on it.

"Even if there is an increased incidence of macular degeneration, it's relatively small," said Cioffi, who was not involved with the new research.

He also added that people shouldn't start taking aspirin for no particular reason, either.

"I think this is a cautionary note, and it reminds us that every medicine has a risk-benefit profile that we have to be aware of - even aspirin," said Cioffi.

SOURCE: http://bit.ly/10IL4sm and http://bit.ly/UUEuKd JAMA Internal Medicine, online January 21, 2013.