Nouvelles 2019

Cette section vous fera découvrir les plus récents travaux des membres de la SQHA. Chaque mois, vous trouverez le résumé d’un nouvel article scientifique publié par un de nos membres, ainsi qu’un lien vous permettant d’aller lire l’article scientifique en question.

• La rigidité artérielle résultant d’une calcification aortique affecte le débit sanguin cérébral et mène à des déficits cognitifs

  Muhire G, Iulita MF, Vallerand D, Youwakim J, Gratuze M, Petry FR, Planel E, Ferland G, Girouard H.

  Background : Arterial stiffness is associated with cognitive decline and dementia; however, the precise mechanisms by which it affects the brain remain unclear. Methods and Results : Using a mouse model based on carotid calcification this study characterized mechanisms that could contribute to brain degeneration due to arterial stiffness. At 2 weeks postcalcification, carotid stiffness attenuated resting cerebral blood flow in several brain regions including the perirhinal/entorhinal cortex, hippocampus, and thalamus, determined by autoradiography ( P<0.05). Carotid calcification impaired cerebral autoregulation and diminished cerebral blood flow responses to neuronal activity and to acetylcholine, examined by laser Doppler flowmetry ( P<0.05, P<0.01). Carotid stiffness significantly affected spatial memory at 3 weeks ( P<0.05), but not at 2 weeks, suggesting that cerebrovascular impairments precede cognitive dysfunction. In line with the endothelial deficits, carotid stiffness led to increased blood-brain barrier permeability in the hippocampus ( P<0.01). This region also exhibited reductions in vessel number containing collagen IV ( P<0.01), as did the somatosensory cortex ( P<0.05). No evidence of cerebral microhemorrhages was present. Carotid stiffness did not affect the production of mouse amyloid-β (Aβ) or tau phosphorylation, although it led to a modest increase in the Aβ40/Aβ42 ratio in frontal cortex ( P<0.01). Conclusions : These findings suggest that carotid stiffness alters brain microcirculation and increases blood-brain barrier permeability associated with cognitive impairments. Therefore, arterial stiffness should be considered a relevant target to protect the brain and prevent cognitive dysfunctions.

  J Am Heart Assoc 2019 8(9):e011630. Doi: 10.1161/JAHA.118.011630