Hemodynamic correlates of vascular risk factors in patients with Alzheimer's disease

Abstract

Background: Although hypertension, diabetes, dyslipidemia, congestiveheart failure (CHF), and unsaturated fatty acid (UFA) are now considered asvascular risk factors of Alzheimer's disease (AD), there were only a fewreports concerning the influence those risk factors on the hemodynamicpahtophysiology underlying AD patients. Recent literature reported an influenceof eiocosapentaenoic Acid (EPA) in AD patients. Only a few evidence draw attention to the participation of UFA in the pathophysiology underlying AD. To clarify thehemodynamic influence from the vascular risk factors in patients with AD, weinvestigated the relationship between the cerebral blood flow images providedby SPECT and HOMA-R, LDL-C/HDLC (L/H ratio), brainnatriuretic peptide (BNP), arachidonic acid / EPA (AA/ EPA) ratio in ADpatients. Methods: The present study was based on 72 patients (28 menand 44 women) who were diagnosed as having a probable AD according to theNINCDS-ADRDA criteria. Their mean age was 77.5±6 7.4 years old. All patients underwent laboratory testings, neuropsychological evaluation including Min-Mental State Exam (MMSE) and Clock Drawing Test (CDT), MRI and ,99mTcECD SPECT. The relationship between MMSE and vascular riskfactors was analyzed statistically. Based on the evaluationaccording to the level of AA/EPA ratio, all patients were classified into 3groups: those with high (Group A), moderate (Group B) and low level (Group C). The statistical parametric mapping (SPM) was used in the comparison ofthe hypoperfusion patterns of SPECT images. Results: MMSE score negatively correlated with AA/EPA ratio (p < 0.01) as well as with L/Hratio (p < 0.01). CDT score negatively corrected with onlyAA/EPA ratio. As compared with Group A, Group C showed a significanthypoperfusion in the right angular gyrus and supramarginal gyrus, although GroupB showed no significant difference on SPM. Conclusions: Since the parietal hypoperfusion which was associated withthe increase in AA/EPA in our results in elderly AD patients, the AA/EPA ratio may strongly influence on the hemodynamic pathophysiology underlying AD.