Migraines alter the brain at the microscopic level

Work by American researchers has highlighted microscopic changes in the brain in patients suffering from migraines.

Using magnetic resonance imaging, researchers have identified a clear anatomical change that occurs in the brains of migraine patients. This is the first time that a study has illustrated this impact with this level of precision. This work may perhaps lead to new therapeutic avenues for treating them.

Migraines are recurring headaches, often quite violent, that usually affect only one side of the head. They are often accompanied by a slew of other disabling symptoms. One can in particular cite the famous “aura” which accompanies certain migraines, and which led to the introduction of the term “ophthalmic migraine”.

Headaches still misunderstood

Without being a major public health problem, migraines are still disabling, and sometimes even almost disabling for people who suffer from them. And this represents a considerable number of patients. According to this study, 12% of the world’s population suffers from episodic migraines. 1 to 2% would be subject to chronic migraines.

The problem is that their exact origin is still quite mysterious. At present, no one is able to say with certainty what physiological mechanisms cause these headaches. There is therefore no satisfactory therapeutic solution that would take the problem to the root. In most cases, those concerned must content themselves with fighting the symptoms, often with painkillers.

But that could be starting to change thanks to the work of researchers at the University of South California (USC). They used a fairly recent magnetic resonance imaging (MRI) technique to observe the brains of migraine patients, with very interesting results.

The technique in question is called 7T MRI (for 7 Tesla, the unit that represents the intensity of a magnetic field). It delivers images with extremely high spatial resolution and contrast. This allows researchers (and even clinicians today) to perform extremely thorough examinations. The perfect tool for tracking down subtle changes in the human body.

Small “holes” in the brain

The researchers used it to explore the ciboulot of 25 people. 20 of them were prone to episodic or chronic migraines. The other 5 were healthy subjects who served as a control group.

In the 20 migraine subjects, they identified a strange peculiarity in structures called spaces of Virchow-Robin, or perivascular spaces. These are small fluid-filled spaces that surround blood vessels. Specialists consider that they play an important role in the maintenance of the brain.

The small black dots correspond to the enlarged perivascular spaces, or EPEs. © Xu et al.

Sometimes these spaces are dilated; if present, they appear on MRI scans as small black holes. This is a normal phenomenon observed even in healthy brains. But several studies suggest that a large number of dilatations could be a warning sign of a neurodegenerative disease.

However, the USC team discovered that the number of dilatations was significantly higher in the brains of migraine patients. These spaces were notably concentrated in the semi-oval centre. It is an abundant layer of white matter (very vulgarly, the material made up of the “tails” of neurons) located in the middle of the brain.

According to the authors, this is the first time that this type of change has been identified in this region of the brain. This study therefore opens up a new avenue of research that could help to understand the mechanisms of migraine.

The white dots correspond to small lesions associated with enlarged perivascular spaces. © Xu et al.

These perivascular spaces are part of the draining system of the brain says Wilson Xu, a medical doctor at USC. ” Studying how they contribute to migraines could help us understand how they arise “, he suggests.

A tenuous but promising line of research

The researchers also offer a first element of response in this direction. They also showed that there is a correlation between enlarged perivascular spaces (EPE) and small lesions observed in the white matter. ” These lesions are significantly related to the presence of EPEs says Xu. “ This suggests that these changes could lead to the development of new lesions. “.

But the authors also point out that we must be cautious with regard to this last hypothesis. In practice, we are faced with a chicken and egg problem. Are these lesions at the origin of EPE, which would then cause migraines? Or is it some other physiological change associated with these headaches that causes the observed changes in the brain? It is very difficult to determine the exact causal relationship.

The USC researchers therefore hope that their findings will pave the way for further work on a larger scale. ” The results of our study could inspire further large-scale studies to investigate how these microscopic brain changes contribute to different types of migraines. says Xu. ” Ultimately, this could help us develop new ways to diagnose and treat migraines. “, he concludes.

The text of the study will be available here on December 1, at the end of the annual meeting of the Radiological Society of North America.

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