Europe South Asia Asia Pacific Americas Middle East Africa BBC Homepage World Service Education

Front Page



UK Politics







Talking Point

In Depth

On Air

Low Graphics

Wednesday, August 4, 1999 Published at 13:01 GMT 14:01 UK


Immune system 'worsens Alzheimer's'

The interaction could destroy neurons

The body's attempts to fight off Alzheimer's disease could do more damage to the brain than the plaques that are thought to cause the condition but a common painkiller could be used to slow its progress, scientists have said.

When the painkiller ibuprofen was given to rats in the laboratory injected with a substance to cause Alzheimer's it kept the disease at bay for 90 days.

One characteristic of Alzheimer's is that plaques - made of a protein called beta-amyloid - are formed in the brain.

It had been thought that these were what caused the degeneration of brain tissue associated with the disease, and that they were thus responsible for the impaired function and dementia it causes.

However, researchers at the University of Ulster have found that more damage is done to the brain when particles produced by the body's immune system came into contact with the plaques.

They said the two react to produce toxins that destroy brain tissue, while the amyloid plaques on their own probably do little damage.

Rat model

The team, led by Dr Eugene O'Hare, conducted their experiments on rats, injecting them to stimulate the growth of plaques and then monitored them.

Nothing happened for 35 days, and then the animals started to show signs of impaired function. The researchers realised that was when the immune system became aware of the plaques and started to fight them off.

They found that when immune system chemicals came into contact with the plaques, they produced inflammatory toxins that washed over surrounding brain cells and damaged them.

"Most probably, the amyloid itself has a minimal effect on the immune system on the neurons, especially in the early stages of the disease - in fact, it's the immune system's efforts to help that are causing a bigger problem," Dr O'Hare said.

Slow progress

The team combined their findings with those of another study, which noted that arthritis patients who took anti-inflammatory drugs had a lower incidence of Alzheimer's than the general population.

They gave ibuprofen - an anti-inflammatory drug - to another set of rats and found that it slowed down progress of the disease, with the rats showing no impairments 90 days later.

"The anti-inflammatory drug protected them from the memory and learning deficits that occur normally when they are untreated," Dr O'Hare said.

However, he stressed that this was only the case in their rat model.

A spokeswoman for the Alzheimer's Disease Society said it was too early to comment on the significance of the findings.

However, she added: "It's been known for some time that anti-inflammatories may have a preventive effect on Alzheimer's Disease."

Advanced options | Search tips

Back to top | BBC News Home | BBC Homepage | ©

Health Contents

Background Briefings
Medical notes

Relevant Stories

02 Aug 99 | Health
Dame Iris's brain aids Alzheimer's research

05 Mar 99 | Health
Alzheimer's drug success

16 Sep 98 | Health
Alzheimer's risk pinned on dad

05 Jun 98 | Health
Scientists find dementia gene

Internet Links

Alzheimer's Disease Society

Alzheimer's Europe

The BBC is not responsible for the content of external internet sites.

In this section

Disability in depth

Spotlight: Bristol inquiry

Antibiotics: A fading wonder

Mental health: An overview

Alternative medicine: A growth industry

The meningitis files

Long-term care: A special report

Aids up close

From cradle to grave

NHS reforms: A guide

NHS Performance 1999

From Special Report
NHS in crisis: Special report

British Medical Association conference '99

Royal College of Nursing conference '99