Cerebral amyloid angiopathy is associated with decreased functional brain connectivity

Cerebral amyloid angiopathy (CAA) is a major cause of intracerebral hemorrhage and neurological decline in the elderly. CAA results in focal brain lesions, but the influence on global brain functioning needs further investigation. Here we study functional brain connectivity in patients with Dutch type hereditary CAA using resting state functional MRI. Twenty-four DNA-proven Dutch CAA mutation carriers (11 presymptomatic, 13 symptomatic) and 29 age-matched control subjects were included. Using a set of standardized networks covering the entire cortex, we assessed both within- and between-network functional connectivity. We investigated group differences using general linear models corrected for age, sex and gray matter volume. First, all mutation carriers were contrasted against control subjects and subsequently presymptomatic- and symptomatic mutation carriers against control subjects separately, to assess in which stage of the disease differences could be found. All mutation carriers grouped together showed decreased connectivity in the medial and lateral visual networks, default mode network, executive control and bilateral frontoparietal networks. Symptomatic carriers showed diminished connectivity in all but one network, and between the left and right frontoparietal networks. Presymptomatic carriers also showed diminished connectivity, but only in the frontoparietal left network. In conclusion, global brain functioning is diminished in patients with CAA, predominantly in symptomatic CAA and can therefore be considered to be a late consequence of the disease.Paroxysmal Cerebral Disorder

[Accepted Manuscript] Presymptomatic atrophy in autosomal dominant Alzheimer's disease: A serial MRI study.

Identifying at what point atrophy rates first change in Alzheimer's disease is important for informing design of presymptomatic trials. Serial T1-weighed magnetic resonance imaging scans of 94 participants (28 noncarriers, 66 carriers) from the Dominantly Inherited Alzheimer Network were used to measure brain, ventricular, and hippocampal atrophy rates. For each structure, nonlinear mixed-effects models estimated the change-points when atrophy rates deviate from normal and the rates of change before and after this point. Atrophy increased after the change-point, which occurred 1-1.5 years (assuming a single step change in atrophy rate) or 3-8 years (assuming gradual acceleration of atrophy) before expected symptom onset. At expected symptom onset, estimated atrophy rates were at least 3.6 times than those before the change-point. Atrophy rates are pathologically increased up to seven years before "expected onset". During this period, atrophy rates may be useful for inclusion and tracking of disease progression

Amyloid imaging of dutch‐type hereditary cerebral amyloid angiopathy carriers

Objective To determine whether amyloid imaging with the positron emission tomography (PET) agent Pittsburgh compound B (PiB) can detect vascular β‐amyloid (Aβ) in the essentially pure form of cerebral amyloid angiopathy associated with the Dutch‐type hereditary cerebral amyloid angiopathy (D‐CAA) mutation. Methods PiB retention in a cortical composite of frontal, lateral, and retrosplenial regions (FLR) was measured by PiB‐PET in 19 D‐CAA mutation carriers (M+; 13 without neurologic symptoms, 6 with prior lobar intracerebral hemorrhage) and 17 mutation noncarriers (M−). Progression of PiB retention was analyzed in a subset of 18 serially imaged individuals (10 asymptomatic M+, 8 M−). We also analyzed associations between PiB retention and cerebrospinal fluid (CSF) Aβ concentrations in 17 M+ and 11 M− participants who underwent lumbar puncture and compared the findings to PiB‐PET and CSF Aβ in 37 autosomal dominant Alzheimer disease (ADAD) mutation carriers. Results D‐CAA M+ showed greater age‐dependent FLR PiB retention (p < 0.001) than M−, and serially imaged asymptomatic M+ demonstrated greater longitudinal increases (p = 0.004). Among M+, greater FLR PiB retention associated with reduced CSF concentrations of Aβ40 (r = −0.55, p = 0.021) but not Aβ42 (r = 0.01, p = 0.991). Despite comparably low CSF Aβ40 and Aβ42, PiB retention was substantially less in D‐CAA than ADAD (p < 0.001). Interpretation Increased PiB retention in D‐CAA and correlation with reduced CSF Aβ40 suggest this compound labels vascular amyloid, although to a lesser degree than amyloid deposits in ADAD. Progression in PiB signal over time suggests amyloid PET as a potential biomarker in trials of candidate agents for this untreatable cause of hemorrhagic stroke. ANN NEUROL 2019;86:616–62

Amyloid imaging of dutch-type hereditary cerebral amyloid angiopathy carriers

Functional Genomics of Muscle, Nerve and Brain Disorder