Scientists shed light on causes of epilepsy

By Martina Fuchs

LONDON, Nov 24 (Reuters) - A breakdown in a reaction between immune cells and blood vessels in the brain appears to play a key role in epilepsy, Italian researchers said on Monday.

The discovery could mean that some modern antibody-based drugs designed to modify the immune system used in other diseases may one day help fight the debilitating disorder.

A study of mice showed how immune cells sticking to blood vessels in the brain caused inflammation that contributed to epileptic seizures, Gabriela Constantin of the University of Verona in Italy and colleagues reported.

The finding could lead to new treatments to prevent the condition that affects about 1 percent of the general population worldwide, said Constantin, who led the study published in the journal Nature Medicine.

"This mechanism was not previously suspected in epilepsy," she said in a telephone interview.

Epilepsy is considered incurable but medicines can control seizures in most people with the common neurological disorder, although sometimes they can have severe side effects.

Many seizures -- which are caused by excessive electrical activity in the brain -- involve loss of consciousness, with the body twitching or shaking. People who have more than one seizure are considered to have epilepsy.

The researchers found that during a seizure the brain released a chemical that caused the white blood cells, or leukocytes, to stick to blood vessels. The immune cells protect the body from threats such as bacteria, viruses, and infections.

But when these immune cells stuck to the brain blood vessels they caused damage by releasing molecules that caused inflammation and contributed to seizures in mice, Constantin said.

"We found a lot of inflammation in this process in the generation of a new seizure," she said.

Mice that received monoclonal antibodies to block the immune cells from sticking to blood vessels had a dramatic reduction of seizures, in some cases 100 percent, Constantin said.

The treatment worked in a similar way to Elan Corp Plc's (ELN.I) multiple sclerosis drug Tysabri and Genentech Inc's DNA.N Raptiva for psoriasis, she added.

This means these kinds of drugs might also one day be used to treat epilepsy and the findings could also lead to new anti-inflammatory treatments for epilepsy, she said.

"We predict other inflammatory drugs can work and be discovered for use in humans," she said. "We have preliminary data on other inflamatory mechanism." (Reporting by Martina Fuchs, Editing by Michael Kahn)