In the brain and its borders, blood vessels coexist with lymphatic vessels exclusively in the dura mater, the outermost layer of meninges. Dural lymphatics are present in various vertebrate species, including humans, and a cluster of experimental studies in the mouse strongly suggest their relevance in the pathophysiology of chronic and acute neurological disorders in humans. Demonstrating this assumption is however still at stake and the lymphatic regulatory mechanisms involved remain poorly characterized. Our main objective is to assess dural lymphatics contribution to the pathophysiology of a rare neurological disorder: idiopathic intracranial hypertension (IIH). In IIH patients, intracranial hypertension causes severe headache and visual loss and is associated with a stenosis of dural sinuses and abnormal retention of fluids in the central nervous system. Angioplasty treatment by stent placement into venous sinuses is frequently followed by recurrent stenosis suggesting that, in addition to the blood vessels, the duro-lymphatic environment contributes to disease progression. Several studies have found hot spots of lymphatic uptake at confluence points between cerebral veins and dural sinuses. Based on this premise, the investigators predict a causal link between lymphatic and venous behavior around dural sinuses and the remodeling of dural lymphatics in neurovascular conditions such as IIH. Our approach will combine radiological observations from human patients with experimental analyses in mouse models. The investigators have recently developed a technique of high resolution vessel wall imaging to explore and compare the lymphatic networks between individuals. This advanced MR-imaging technique has been validated through a translational study comparing the lymphatic networks in mice and humans (Jacob et al. 2022, JExpMed). Using this tool, the investigators aim to monitor dural lymphatic and sinus wall abnormalities in patients with IIH. In this view, cohorts of IIH patients and controls without neurological disorders (n = 20/cohort) will be scanned by MRI to perform high resolution vessel wall imaging of the dural lymphatics, sinus and cerebral veins.
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Morphometric study of the dural lymphatic network in patients with IIH vs controls
Timeframe: Immediate