Abstract 2749: Amyloid-beta (1-42) is Reduced in CSF in Vascular Cognitive Impairment
Introduction: Vascular cognitive impairment (VCI) and Alzheimer’s disease (AD) have a high degree of overlap in a number of large autopsy series. However, few studies have examined the overlap during life. VCI is a heterogeneous disorder due to large and small vessel vascular disease (SVD). Biomarkers of inflammation are present in the SVD, which is a progressive form of VCI that is characterized by MRI findings of lacunar strokes and white matter hyperintensities (WMHs), executive dysfunction, focal neurological findings, apathy, urinary problems and gait imbalance. Recently, we showed an association between a reduced matrix metalloproteinase-2 (MMP-2) CSF index and disruption of the blood-brain barrier (BBB) in SVD. We hypothesized that patients with both VCI and AD would show CSF and MRI biomarkers for both diseases.
Patients and Methods: Patients (N=60) with VCI underwent neurological and neuropsychological testing. MRI was done with FLAIR, proton magnetic resonance spectroscopy (1H-MRS) to measure ischemia with N-acetylaspartate (NAA), and dynamic contrast-enhanced MRI (DCEMRI) to measure BBB transfer constants (Ki). CSF (N=37) was obtained by lumbar puncture for measurements of albumin index, MMP-2 and MMP-9 indexes, ABeta 1-42, total-tau (T-Tau) and hyperphosphorylated-tau (P-Tau).
Results: BD patients had large WMHs, while large vessel (multi-infarct and single strategic stroke) patients had small WMHs. NAA was used as a biomarker of lesion size due to ischemic damage in the white matter. ROC plots showed that a NAA cut-point of 12 separated patients with large WMHs (low NAA) from small WMHs (p<0.0001). Ki transfer constants above 0.0018 (ROC; p<0.0001) and MMP-2 below 0.0099 (ROC; p<0.0001) were considered abnormal. SVD patients had reduced ABeta 1-42 compared to control CSF. P-Tau was unaffected. Abnormal values for Ki and MMP-2 index were present in both large and small vessel disease patients.
Conclusions: Our results show that SVD patients have significantly reduced levels of ABeta 1-42 in CSF, suggesting impairment in amyloid metabolism associated with vascular disease. These findings conform to the autopsy findings and suggest that multimodal biomarkers may provide information during life about the presence of both AD and VCI.
- © 2012 by American Heart Association, Inc.