• aging;
  • Alzheimer's disease;
  • hypertension;
  • myoinositol;
  • proton magnetic resonance spectroscopy

OBJECTIVES: Hypertension is a risk factor for dementia and is associated with some of the brain changes that are found in Alzheimer's disease and other neurodegenerative diseases, such as atrophy and neurofibrillary tangles. We evaluated the cerebral white matter biochemical pattern in healthy older subjects, older patients with chronic hypertension, and patients with Alzheimer's disease (AD) using proton magnetic resonance spectroscopy (1H-MRS).

DESIGN: Cross-sectional study.

SETTING: University-affiliated outpatient clinic.

PARTICIPANTS: Ten healthy older subjects, 10 cognitively intact older patients with chronic hypertension, and 10 older patients with early AD.

MEASUREMENTS: All subjects underwent clinical examination, neuropsychological assessment, and 1H-MRS to measure N-acetylaspartate (NAA), myoinositol, choline, and creatine resonance signals in an 8-cm3 voxel located in the paratrigonal white matter region bilaterally. NAA/creatine, myoinositol/creatine, and choline/creatine ratios were measured, and the mean values were compared using one-way analysis of variance with Tukey test for post hoc analysis.

RESULTS: A significantly higher mean myoinositol/creatine (ratio ± standard deviation) was found in hypertensive patients (0.67 ± 0.05) and in AD patients (0.68 ± 0.08) than in controls (0.56 ± 0.04) (P < .001). Conversely neither NAA/creatine ratio nor choline/creatine ratio differed among the three groups.

CONCLUSIONS: In this study, cognitively intact chronic hypertensive older patients had a higher white matter myoinositol/creatine ratio compared with healthy older subjects, suggesting that myoinositol may be a sensitive marker of the effects of chronic hypertension on the brain. Moreover, the similar increase of myoinositol/creatine ratio in patients with hypertension and in those with early AD provides further evidence of common brain changes with these conditions.