towards better care thanks to molds?

What if mussels could improve the treatment of strokes? The PhIND (Physiopathology and Imaging of Neurological Disorders) laboratory at the University of Caen recently developed PHySIOMIC*, a new contrast agent inspired by the adhesive structure of mussels, making it possible to precisely detect microthrombi – tiny blood clots. which worsen the after-effects of a stroke- in the brain via MRI. These promising results were published in June 2024 in the prestigious scientific journal Nature communications.

What is a thrombus?

A thrombus is a clot that blocks a blood vessel. When it blocks blood flow to the brain, it causes an ischemic stroke. “It is then essential to quickly eliminate this thrombus to restore blood circulation in the affected area of ​​the brain, in order to limit the damage,” explain the authors of the study. “Doctors currently have two options to get rid of it: inject a drug, tissue plasminogen activator (tPA), into the bloodstream, which induces the enzymatic dissolution of the blood clot, or extract it mechanically by catheterization . »

Current methods are insufficient

Despite the virtues of these methods, there remain many cases (around 30%) in which, although the main clot has been successfully removed, the cerebral microcirculation remains blocked. Concretely, the thrombi sometimes fragment into smaller thrombi (called microthrombi) and obstruct the downstream microcirculation. Particularly harmful, “they are responsible for a majority of the after-effects of patients with significant disability after a stroke”, which, let us remember, is the second cause of acquired disability in France. Problem: they are very difficult to identify, even with the latest generation imaging. “PHySIOMIC offers a new method to visualize them, predict the extent of brain damage and evaluate the effectiveness of thrombolytic treatments,” welcomes Doctor Charlène Jacqmarcq, co-author of the study.

Exceptionally adhesive microparticles

This contrast agent is based on magnetic microparticles capable of attaching to microthrombi. “Their magnetic properties provide an MRI signal and thus enable their diagnosis”indicate the researchers. To find this material ” ideal “, they were inspired by marine biology. More precisely from a substance discovered on the byssus of marinière mussels (solid and adhesive filaments produced by these molluscs to attach to rocks and other underwater surfaces): polydopamine. Its exceptional adhesion properties have won over scientists!

Conclusive tests on mice

Tests carried out on mouse models of ischemic stroke were conclusive. Moreover, “PHySIOMIC particles demonstrated good biocompatibility and biodegradation capacity, making them safe to use for in vivo diagnostics. These particles are primarily eliminated by macrophage cells in the liver and spleen, without unwanted accumulation in other organs. rejoice its designers. They now plan to continue their studies with “broader and more diversified clinical models”, and to evaluate its effectiveness with targeted thrombolytic agents (drugs designed to dissolve blood clots). A promising prospect for the 110,000 people affected by this type of stroke in France.

* Polydopamine hybridized iron oxide mussel inspired clusters

© Stocklib / hakule