Regional structural differences in the brain related to high blood pressure

OBJECTIVE: Hypertension is characterized by elevations in sympathetic nerve activity that are consistently observed regardless of severity and treatment status. Structural changes in the brain occur with hypertension, including grey matter changes, which are associated with elevated blood pressure (BP). However, whether or not these changes are associated with increased sympathetic nerve activity in hypertensives has not been investigated. The present study aimed to determine the relationship between regional grey matter density, muscle sympathetic nerve activity (MSNA) and BP in people with hypertension, compared to normotensive participants. METHODS: T1-weighted anatomical scans (3T MRI) were acquired from 35 hypertensive and 57 normotensive participants; MSNA was successfully obtained from the right peroneal nerve in 26 hypertensives and 55 normotensives. Voxel-based morphometry (VBM) analysis was conducted to determine regional grey matter density and the relationships between MSNA and BP in both groups. RESULTS: An inverse relationship between MSNA and grey matter density was found in the left dorsolateral prefrontal cortex, right precentral gyrus, left superior parietal lobule, and right cuneus in hypertensives but not in normotensives. In addition, hypertensive participants showed a negative correlation between grey matter density and DBP in the right precentral gyrus and left postcentral gyrus, which was not observed in controls. CONCLUSION: We have shown an association between specific nuclei of the brain with elevated MSNA and BP in hypertension. These findings suggest a functional link between grey matter density in specific brain nuclei and MSNA and BP in patients with hypertension.