Aortic reservoir characteristics and brain structure in people with type 2 diabetes mellitus; a cross sectional study

Abstract

Background: Central hemodynamics help to maintain appropriate cerebral and other end-organ perfusion,and may be altered with ageing and type 2 diabetes mellitus (T2DM). We aimed to determine the associationsbetween central hemodynamics and brain structure at rest and during exercise in people with and without T2DM.Methods: In a sample of people with T2DM and healthy controls, resting and exercise measures of aortic reservoircharacteristics (including excess pressure integral [Pexcess]) and other central hemodynamics (includingaugmentation index [AIx] and aortic pulse wave velocity [aPWV]) were recorded. Brain volumes (including graymatter volume [GMV] and white matter lesions [WML]) were derived from magnetic resonance imaging (MRI) scans.Multivariable linear regression was used to study the associations of hemodynamic variables with brain structure inthe two groups adjusting for age, sex, daytime systolic BP (SBP) and heart rate. Results: There were 37 T2DM (63 ± 9 years; 47% male) and 37 healthy individuals (52 ± 8 years; 51% male). In T2DM,resting aPWV was inversely associated with GMV (standardized β = -0.47, p = 0.036). In healthy participants, restingPexcess was inversely associated with GMV (β = -0.23, p = 0.043) and AIx was associated with WML volume (β = 0.52,p = 0.021). There were no associations between exercise hemodynamics and brain volumes in either group. Conclusions: Brain atrophy is associated with resting aortic stiffness in T2DM, and resting Pexcess in healthyindividuals. Central vascular mechanisms underlying structural brain changes may differ between healthy individualsand T2DM.