Association between cardiovagal baroreflex sensitivity and baseline cerebral perfusion of the hippocampus.
OBJECTIVE
A failure to control perfusion pressure due to impaired baroreflex sensitivity (BRS) could potentially cause chronic brain hypoperfusion, leading to cognitive dysfunction. The primary aim of this study was to determine whether BRS was associated with regional cerebral blood flow as measured by MRI arterial spin labeling (ASL) technique.


METHODS
Baroreflex sensitivity was measured using the Valsalva maneuver technique in 52 middle-aged normotensive adults (49 ± 1 years), and phase IV of the Valsalva maneuver was used for analyses. Cerebral perfusion was measured using the ASL MRI technique in 10 pre-determined brain regions of interest.


RESULTS
Hippocampal perfusion was correlated with BRS (R (2) = 0.17, P = 0.01). No association was observed between BRS and cerebral perfusion in the other brain regions of interest. Partial correlational analyses revealed that BRS was an important predictor of hippocampal perfusion, explaining 11 % of the variability independent of other covariates. When participants were divided into tertiles of BRS (11.8 ± 1.9 and 3.5 ± 0.1 ms/mmHg for the highest and lowest tertiles), regional cerebral perfusion of the hippocampus was significantly lower in the lowest BRS tertile than in the highest tertile (39.1 ± 4.3 and 60.5 ± 8.4 ml/100 g/min).


CONCLUSIONS
Baroreflex sensitivity in midlife is positively associated with regional cerebral perfusion of the hippocampus, and impaired BRS appears to be related to brain hypoperfusion even in apparently healthy middle-aged adults. Future longitudinal studies based on the present cross-sectional findings may help to further define the relationship between BRS to cognitive dysfunction.
Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, 78712, USA.
Jitanan
J
Laosiripisan
Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, 78712, USA.
Takashi
T
Tarumi
Department of Psychology, University of Texas at Austin, Austin, TX, 78712, USA.
Mitzi M
MM
Gonzales
Department of Psychology, University of Texas at Austin, Austin, TX, 78712, USA.
Andreana P
AP
Haley
Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, 78712, USA. htanaka@austin.utexas.edu.
Hirofumi
H
Tanaka
D000328:Adult; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006624:Hippocampus / Q000098:blood supply* / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014636:Valsalva Maneuver / Q000502:physiology*
Alzheimer’s disease; Arterial spin labeling; Autonomic dysfunction; MRI