Systemic Vascular Health Associated With Widespread Brain Changes
The association of systemic vascular health with structural MRI measures was greatest primarily in the medial temporal lobes
Systemic vascular health has an impact on the structure and function of the brain, with several cardiovascular and metabolic conditions associated with and potentially predictive of thinning of the temporal lobe, cerebral hypoperfusion, and loss of white matter microstructural integrity, according to study results published in Annals of Neurology.
Patients in the discovery dataset (n=390) had systemic vascular health assessed via measurement of cardiovascular and metabolic conditions (eg, hypertension, hyperlipidemia, cardiac-arrhythmias, coronary artery disease, congestive heart failure, diabetes mellitus, and stroke) on brain structure, as well as brain perfusion and diffusion. In an independent validated data set (n=1035), investigators assessed the rationale of using cerebrovascular health as a biomarker for cognition and amyloidosis. All patients' data were obtained from a population-based study in Olmsted County, Minnesota. Associations between cardiovascular and metabolic conditions and brain health were assessed in analyses adjusted for age, sex, education/occupation, and Alzheimer's disease (AD) burden.
A greater burden of cardiovascular and metabolic conditions was associated with decreased thickness of the medial temporal lobe and middle temporal pole (P <.05). A higher vascular risk was also associated with increased superior parietal lobe thickness (P <.05). In addition, patients with a greater number of cardiovascular and metabolic conditions had reduced perfusion throughout the brain (P <.05).
Microstructural integrity of the genu of the corpus callosum was found to be a good predictive biomarker for cognitive performance to a greater degree than amyloid deposition. Cardiovascular and metabolic conditions were also predictive of genu fractional anisotropy in the validation cohort (estimate −0.003; standard error 0.001; P =.004).
The investigators highlighted the use of global measures, including cardiovascular and metabolic conditions and global cognition for developing a cerebrovascular biomarker, as a potential study limitation but noted that this allowed them to develop a cerebrovascular biomarker with broader utility.
In addition, the study's investigators suggested that additional research “is warranted to evaluate the performance of the proposed biomarker for longitudinal measurements, in different samples as well as among midlife participants.”
Vemuri P, Lesnick TG, Przybelski SA, et al. Development of a cerebrovascular MRI biomarker for cognitive aging. Ann Neurol.2018;84(5):705-716.