Blood–Brain Barrier Breakdown in Relationship to Alzheimer and Vascular Disease

• Published in: Annals of neurology Vol. 90; no. 2; pp. 227 - 238
• Main Authors: Lin, Zixuan, Sur, Sandeepa, Liu, Peiying, Li, Yang, Jiang, Dengrong, Hou, Xirui, Darrow, Jacqueline, Pillai, Jay J., Yasar, Sevil, Rosenberg, Paul, Albert, Marilyn, Moghekar, Abhay, Lu, Hanzhang
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.08.2021; Wiley Subscription Services, Inc
• Subjects: Aged; Albumin; Alzheimer Disease - cerebrospinal fluid; Alzheimer Disease - diagnostic imaging; Alzheimer's disease; Amyloid beta-Peptides - cerebrospinal fluid; Biomarkers; Blood-brain barrier; Blood-Brain Barrier - diagnostic imaging; Blood-Brain Barrier - metabolism; Breakdown; Capillary Permeability - physiology; Cerebrospinal fluid; Cognitive ability; Cognitive Dysfunction - cerebrospinal fluid; Cognitive Dysfunction - diagnostic imaging; Cross-Sectional Studies; Female; Humans; Hypercholesterolemia; Imaging techniques; Impairment; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Marking and tracking techniques; Membrane permeability; Middle Aged; Neurodegenerative diseases; Neuroimaging; Pathology; Peptide Fragments - cerebrospinal fluid; Permeability; Phase contrast; Risk analysis; Risk factors; Serum albumin; Serum Albumin, Human - cerebrospinal fluid; tau Proteins - cerebrospinal fluid; Vascular diseases; Vascular Diseases - cerebrospinal fluid; Vascular Diseases - diagnostic imaging
• ISSN: 0364-5134; 1531-8249; 1531-8249
• DOI: 10.1002/ana.26134

Objective Blood–brain barrier (BBB) breakdown has been suggested to be an early biomarker in human cognitive impairment. However, the relationship between BBB breakdown and brain pathology, most commonly Alzheimer disease (AD) and vascular disease, is still poorly understood. The present study measured human BBB function in mild cognitive impairment (MCI) patients on 2 molecular scales, specifically BBB's permeability to water and albumin molecules. Methods Fifty‐five elderly participants were enrolled, including 33 MCI patients and 22 controls. BBB permeability to water was measured with a new magnetic resonance imaging technique, water extraction with phase contrast arterial spin tagging. BBB permeability to albumin was determined using cerebrospinal fluid (CSF)/serum albumin ratio. Cognitive performance was assessed by domain‐specific composite scores. AD pathology (including CSF Aβ and ptau) and vascular risk factors were examined. Results Compared to cognitively normal subjects, BBB in MCI patients manifested an increased permeability to small molecules such as water but was no more permeable to large molecules such as albumin. BBB permeability to water was found to be related to AD markers of CSF Aβ and ptau. On the other hand, BBB permeability to albumin was found to be related to vascular risk factors, especially hypercholesterolemia, but was not related to AD pathology. BBB permeability to small molecules, but not to large molecules, was found to be predictive of cognitive function. Interpretation These findings provide early evidence that BBB breakdown is related to both AD and vascular risks, but their effects can be differentiated by spatial scales. BBB permeability to small molecules has a greater impact on cognitive performance. ANN NEUROL 2021;90:227–238