This 37-year-old researcher, with two colleagues from the BB@C laboratory (Blood and Brain at Caen-Normandie Editor’s note), synthesized particles called PHySIOMIC to identify and destroy the tiny blood clots responsible for strokes, with more precision and less toxicity for the body than the current process.
Effective in mice, PHySIOMIC still needs to be tested on two “large animals”, then humans, and a procedure must be defined to mass produce it before marketing it, which will not happen for “five to ten years” , according to Thomas Bonnard.
“An ischemic stroke is caused by a clot that migrates from the carotid artery and blocks blood flow in the brain, thus killing neurons. Today, we know how to see large clots in MRI (magnetic resonance imaging, editor’s note)” recalls Mr. Bonnard, “on the other hand, we did not know how to detect the smaller clots, or “microthrombi”.
The PHySIOMIC contrast agent is made up of microparticles of iron oxide and polydopamine: an assembly of molecules of the neurotransmitter dopamine by which neurons usually communicate, used here as a material. Once injected into the bloodstream, it will attach to the microclot and will be visible on MRI thanks to its magnetic properties.
There are “concerns” with the contrast agents currently used based on Gadolinium, “associated in the past with certain risks of renal complications”, according to Thomas Bonnard. This is not the case, according to the researcher, of PHySIOMIC: “It will never have toxic effects, since it exclusively uses materials that are already present in the body. »
90% of strokes are preventable, by adopting the right “prevention” reflexes
A cerebrovascular accident (CVA) is the consequence of impaired blood circulation to the brain: either a blood vessel is blocked, it is then an ischemic accident (80% of strokes), or a blood vessel tears. It causes hemorrhage in or around the brain (this is a hemorrhagic stroke). Brain cells are thus deprived of oxygen and fuel (glucose), leading to neurological after-effects. This is why stroke is one of the leading causes of death worldwide, the leading cause of acquired disability in adults and the second leading cause of dementia in seniors.
Like a mussel to its rock
The “MIC” in PHySIOMIC stands for “Mussel Inspired Clusters” because the mussel, to attach itself to its rock, also uses dopamine. “When we inject something into the blood, proteins “clump” on it and participate in attaching to the microclot,” describes Charlène Jacqmarcq, 30 years old.
This post-doctoral student at BB@C sits in front of a “microfluidic station”: a network of tubes and pumps responsible for reproducing the blood system in which she “simulates strokes” on human blood recovered in partnership with the French establishment blood (EFS).
Once identified, the microthrombi must be destroyed, research carried out by Audrey Picot, a 27-year-old doctoral student at the BB@C laboratory, who adds a tissue plasminogen activator (tPA) to PHySIOMIC. The only pharmacological treatment currently delivered to stroke victims, tPA presents a risk of bleeding which will be reduced by targeting the contrast agent PHySIOMIC, according to Mr. Bonnard.
“We have set up a collaboration with the Australian pharmaceutical company CSL Behring, as well as Inserm Transfert, to develop this diagnostic tool and make it become a theranostic tool: this means that it will both diagnose and make visible microclots, allow their breakdown and restore blood flow in patients,” specifies Ms. Picot.
Private funds
Paid by Inserm from the private funds of CSL Behring, the entire team benefits from the tools of the BB@C laboratory. “Small animal” MRI, magnetic particle imaging scanner (the 1st in France), a super resolution 3D ultrasound machine… “We don’t find this equipment concentrated in a single place in all the research centers, we’re lucky to work here,” rejoices Charlène Jacqmarcq.
