Hypertension puts the brain under pressure

Elevated blood pressure and brain inflammation are recognized as important contributors damaging the small cerebral vessels, also known as small vessel disease (SVD), the latter being a very early cause of neurological diseases like stroke and dementia. Unfortunately, most studies investigating  inflammation linked to SVD rely on peripheral blood markers, which might not accurately capture inflammatory changes within the cerebral white matter (WM).

PhD candidate Gemma Solé-Guardia studied the association between hypertension and cerebral inflammation in WM in a post-mortem study including brains of hypertensive and age-matched normotensive individuals. The research group, led by Amanda Kiliaan, department of Medical Imaging, Anatomy, in collaboration with the departments Neurology (De Leeuw), Geriatrics (Claassen) and Pathology (Kusters) published the results in Acta Neuropathologica Communications on 4 January 2023.

Within this post-mortem study, they studied the foremost common MRI marker of SVD, white matter hyperintensities (WMH; loss of myelinated nerve fibres), and regions at risk of conversion into WMH; the normal-appearing white matter (NAWM), using 7 Tesla MRI and stainings of cerebral inflammatory markers (astroglia and microglia). To accurately investigate inflammatory changes within the WM at microscopical resolution, MRI was aligned to sections stained for neuroinflammatory markers. In older hypertensive adults, cerebral inflammation in WM and surrounding the smallest vessels was found in areas with WMH extending into NAWM. This suggests that cerebral inflammation is a key mechanism of (NAWM conversion to) WMH in individuals with hypertension.

Recently, they are studying the impact of elevated blood pressure on important pathological mechanisms of SVD such as blood-brain barrier integrity, amyloid-beta deposition and neurodegeneration in the same individuals. Eventually this research will contribute to better understanding of the pathology of SVD, and therewith to development of preventative strategies and treatments to attenuate the burden of SVD.

Publication

Association between hypertension and neurovascular inflammation in both normal-appearing white matter and white matter hyperintensities | Acta Neuropathologica Communications | Full Text (biomedcentral.com) Solé-Guardia G, Custers E, de Lange A, Clijncke E, Geenen B, Gutierrez J, Küsters B, Claassen JAHR, de Leeuw FE, Wiesmann M, Kiliaan AJ. Association between hypertension and neurovascular inflammation in both normal-appearing white matter and white matter hyperintensities. Acta Neuropathol Commun. 2023 Jan 4;11(1):2. doi: 10.1186/s40478-022-01497-3. PMID: 36600303.