12.04.2012

"Positive stress" can prevent glaucoma

"Positive stress" can prevent glaucoma

By Adrian Galbreth

Glaucoma is one of the leading causes of blindness in the UK, but new research has claimed that there may be a simple way of helping to combat the development and progression of the disease.

According to specialists at Washington University School of Medicine in St Louis, they have developed a treatment that prevents the optic nerve injury experienced by sufferers of the neurodegenerative disease.

In the study, which is published online in the journal Molecular Medicine, researchers reveal how they increased the resistance of optic nerve cells to damage by repeatedly exposing the mice to low levels of oxygen similar to those found at high altitudes.

The resulting stress of the intermittent low-oxygen environment – termed 'positive stress' by the experts - induces a protective response called tolerance that makes nerve cells in the eye less vulnerable to harm.

Senior author Dr Jeffrey Gidday, associate professor of neurological surgery and ophthalmology at the facility, said stress is typically thought of as a negative thing.

However, this study shows that the right kinds of stress, such as exercise and low-oxygen environments, can precondition cells and induce changes that make them more resistant to injury and disease, he explained.

Although experts previously thought tolerance in the central nervous system only lasted for a few days, Dr Gidday's preconditioning protocol extended the effects of tolerance from days to months.

By exposing mouse models to low oxygen concentrations several times over a two-week period, researchers triggered an extended period of tolerance, with the brain protected from stroke damage for at least eight weeks after pre-conditioning.

"Once we discovered tolerance could be extended, we wondered whether this protracted period of injury resistance could also protect against the slow, progressive loss of neurons that characterises neurodegenerative diseases," Dr Gidday explained.

New clinical trials are now exploring whether stress-induced tolerance can reduce brain damage after acute injuries like stroke, subarachnoid haemorrhage or trauma.

by Martin Burns


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