13 Jul 2017

Migraines - much more than a headache

From Our Changing World, 9:06 pm on 13 July 2017

“A migraine is not just a bad headache. It’s far worse than that. It affects the whole physiology of the sufferer.

“These are things that take people out of action for days – and they cannot be treated with simple painkillers.”

But migraine expert Debbie Hay says there is good news out there for migraine sufferers.

“We really are right on the edge of a new era in the treatment of migraines.”

Migraine sufferer in a darkened room

Migraine sufferers experience visual disturbances and sensitivity to light and noise, as well as severe headaches. Photo: CC BY 2.0 Brian/Flickr

Professor Debbie Hay is a research fellow at the University of Auckland and the Maurice Wilkins Centre for Molecular Discovery. She says that about 20% of people experience migraines, with women three times more likely to suffer them than men.

The exact cause of migraines isn’t known, but there is a strong genetic link, and Debbie says that hormones are probably important as well.

“Because migraines exhibit differently in each person, it’s very hard to determine exactly how they’re caused, what triggers them – it’s different in each person – and we’re not there at all in understanding the underlying mechanisms,” says Debbie.

A new era in migraine treatment

Debbie Hay.

Debbie Hay. Photo: University of Auckland

Despite this, Debbie says that some exciting new treatments might be available as early as 2018.

“We’ve got five pharmaceutical companies fighting to win the race to be the first with a new migraine treatment.”

This race is the result of research which shows that people suffering from migraines are sensitive to a pain-causing hormone called CGRP, or calcitonin gene-related peptide.

“If you give CGRP to a person who suffers from migraine, when they’re not having a migraine,’ says Debbie, “it will trigger a migraine.” In a normal person, a dose of CGRP will only trigger a mild headache.

Debbie says that the pharmaceutical companies are all trying to block the effect of CGRP, although they are tackling it in different ways.

Some have developed antibodies which “mop up this hormone in the bloodstream’, while others have developed antibodies which “target the so-called CGRP receptor in the brain”. Others have developed small molecule drugs that block the hormone.

All five companies are in late stage clinical trials, which include some New Zealand participants. Debbie agrees that there are pros and cons for each of the treatment approaches, but the exciting thing is they appear to be able to stop migraines in chronic sufferers.

Understanding CGRP in the brain

Debbie’s research is focused on understanding the cellular receptors in the brain which are targeted by CGRP. A recent breakthrough was her discovery that there are two cellular receptor targets in the brain, not just one as was commonly believed.

“They are likely to have different effects. One may cause migraines and one may not,” says Debbie. “And we’re trying to understand all the molecular mechanisms that relate to those particular receptors.”

She says it is important to understand how the new drugs that are currently being trialled interact with both these receptors. Debbie studies these interaction using cells in the lab as well as human brains, which have been donated to the Neurological Foundation Douglas Human Brain Bank at the Centre for Brain Research.

Her current work, which is funded by a James Cook Fellowship from the Royal Society Te Aparangi, as well as a Marsden grant, involves looking at brains to find out where the two different CGRP receptors are located. Debbie says that this is a huge task, as the human brain is very large, but to date she has identified both receptors in the brain stem.

Debbie believes that the new migraine treatments being tested at the moment are just the first step and that over time they will be refined to be more effective and have fewer potential side effects. They may also herald a new era in the management of other forms of pain, such as cluster headaches.