Researchers develop treatment for overactive bladder

SYDNEY - Those who suffer from an overactive bladder have reason to be hopeful. Medical researchers have developed an effective treatment for the embarrassing condition.

The treatment was developed by researchers at the University of New South Wales (UNSW).

An overactive bladder is characterised by a frequent urge to urinate. Sufferers live in fear of wetting themselves, which can have a debilitating effect on their lifestyle. Its causes, however, remain a mystery, the website Science Alert reported.

Now researchers investigating bladder function in animals have found that acid inside urine is an important stimulant of cells lining the bladder wall. These in turn release a chemical, ATP, which fires up nerve receptors that signal to the brain that the bladder is full. Researchers have found the existence of specific receptors for acid (ASICs) on the bladder lining.

It is the first connection to be made between acid and bladder function, and raises the possibility that pH levels in urine — which is routinely acidic — can be modified to control the urge to urinate.

“No one really knows what causes overactive bladder - that’s what makes it such a difficult thing to treat,” said lead author Elizabeth Burcher from UNSW’s School of Medical Sciences.

Until now it’s been assumed that the release of the chemical ATP was stimulated primarily by the bladder’s ’stretch’ as it becomes full.

“Acid is a new stimulus that we haven’t been aware of before,” Burcher said.

Current treatments for overactive bladder centre on drugs that reduce the activity of neurotransmitter receptors in the bladder wall.

“These drugs make an awful lot of money for drug companies because people have to take them all the time, but there are side effects such as dry mouth, constipation and drowsiness, and they are only effective in some people,” Burcher said.

“A new more cost-effective approach would be terrific. There’s no doubt it’s an area of unmet need.”

Burcher said the next step would be to conduct similar investigations in humans.

“It’s always difficult to relate animal findings to human tissue, and there are species differences,” she said. “But we’ve shown that acid is a stimulus in two animals - the pig and the rat. There’s no reason to believe it wouldn’t be the case in humans too.”

The findings appeared in the British Journal of Pharmacology.