- Toronto team spots missing link

Toronto researchers have discovered the key to keeping brain cells alive much longer during a stroke, opening the door for new treatments that would make the brain resistant to a stroke's debilitating effects.

Five years of study determined that an ion channel, known as TRPM7, on the surface of brain cells is switched on when the cells are deprived of oxygen and vital nutrients, as happens during a stroke. The channel then funnels a flood of toxins into the cells. Blocking the channel extends the time doctors have to treat the brain's impasse and save brain tissue.

"We were able to make tissues survive in the absence of oxygen and glucose for over three hours," said Dr Michael Tymianski, a neurosurgeon at Toronto Western hospital, who made the discovery along with John MacDonald, a professor of physiology at the University of Toronto.

The finding, published recently in the journal Cell, provides the missing link in cell research to a way to keep brain tissue alive.

"What we've missed in the past - the big gap in our knowledge - was the knowledge about this ion channel," Tymianski said.

"Clot-busting medications are the only treatment we have, but only 2 per cent (of stroke patients) make it to hospital in time for clot-busting drugs to be given."

Tymianski believes it will take scientists a mere three years to turn this discovery into a drug, one that ideally could be administered by paramedics as they rush stroke patients to hospital.

The discovery could also lead to treatments for all kinds of disorders where lack of blood flow is the root of the problem, including mini-strokes, brain trauma, glaucoma, heart disease and blood pressure problems.

Extracted from a report printed in the “Toronto Star” on 26 Dec 2003