a new contrast agent is able to detect the smallest clots

A revolution is underway in magnetic resonance imaging technology. This examination technique makes it possible to produce images of the body in two or three dimensions. It is used in particular to detect a cerebrovascular accident (CVA). At the University of Caen – Normandy, researchers are at the origin of an innovation that could improve its care. They created a new contrast agent, a substance injected to make certain parts of the body more visible, allowing tiny clots to be spotted. This work, carried out as part of the thesis by Dr Charlène Jacqmarcq, under the direction of Dr Thomas Bonnard, research fellow at Inserm, were published in Nature Communications.

Stroke: what are microthrombi, responsible for many after-effects?

Stroke is caused by the presence of a thrombus, or clot, in a blood vessel. “When a patient has an ischemic stroke, it is essential to quickly eliminate this thrombus to restore blood flow to the affected area of ​​the brain in order to limit damage.”specify the authors in a press release. Two techniques can eliminate these clots to restore blood circulation. But in 30% of cases, blood microcirculation remains blocked. “Sometimes thrombi fragment into smaller thrombi (called microthrombi) and obstruct downstream microcirculation, explain the Norman researchers. These microthrombi are particularly harmful and are responsible for a large part of the after-effects of patients suffering from significant disability after a stroke..” However, these microthrombi are very difficult to identify because they are not visible on medical imaging.

MRI and stroke: a contrast product inspired by mussels

Called PHySIOMIC, the new product makes it possible to detect them during an MRI. Researchers have developed magnetic microparticles intended to be injected into the bloodstream that are capable of attaching to microthrombi. This makes it possible to identify them during the MRI. “The challenge was particularly complex because it was necessary to find a material which allowed both the targeting of blood clots while providing sufficient magnetic signal and being completely inert for the body; a material therefore ideally organic”note the authors. They found the answer in marine biology: they were inspired by a material discovered in the byssus of mussels, the filament that allows them to attach to a rock, polydopamine. “Tests carried out on mouse models of ischemic stroke demonstrated that the injection of PHySIOMIC can detect microthrombi with high precision.summarize the researchers. Additionally, PHySIOMIC particles also demonstrated good biocompatibility and biodegradation capability, making them safe to use for in vivo diagnostics.”

A promising technique for detecting and treating strokes

For researchers, this technique could make it possible to create new strategies both for the diagnosis, but also for the management of strokes. Further work will assess the product’s effectiveness in larger trials. In an article from South WestThomas Bonnard specifies that it will take another five to ten years before the product is marketed.