👤 Christopher C Rowe

Sporadic late-onset Alzheimer's disease (AD) is characterized by a long pre-clinical phase where amyloid-beta (Aβ) and tau begin to accumulate in the brain. The primary objective was to determine the age at which AD starts by finding the average population age when both positron emission tomography (PET) Aβ (Aβ-PET) and plasma Aβ42/40 become abnormal. Two high performance immunoprecipitation-mass spectrometry (IP-MS) assays (WashU/C2N and Shimadzu) were tested on samples from 1,450 participants who were diagnosed as cognitively unimpaired (CU), mild cognitive impairment (MCI), or AD-dementia across 4 international cohorts. Natural history modeling and trajectory analyses of the combined Aβ-PET and plasma Aβ42/40 data were analyzed. Data from both assays demonstrated Aβ42/40 undergoes a rapid change at approximately 15 Centiloid (CL), at an average population disease age at 66 years. On average, plasma Aβ42/40 becomes abnormal approximately 2 years before Aβ-PET, whereby it falls sharply to a stable level at the onset of preclinical AD. Average disease age where Aβ42/40 becomes abnormal, and the corresponding Centiloid level are lower for APOE allele carriers compared with non-carriers. Plasma Aβ42/40 ratio presents a step-like function of peripheral change shortly before the detection of plaques by Aβ-PET. Results are consistent with plasma Aβ42/40 falling to a steady-state level in participants with Aβ-PET levels greater than approximately 14CL for both assays. The age at which this occurs is dependent on APOE ε4 carriership, consistent with the approximate 7-year age difference in Centiloid abnormality between carriers and non-carriers. ANN NEUROL 2026;99:1327-1342. Show less

The agreement between plasma Aβ42/40 and Aβ positron emission tomography (PET) is approximately 75 %, with ∼85 % of discrepancies due to positive plasma but negative PET results. It is unclear whether this reflects Aβ changes in plasma before PET-detectable. To assess the influence of Aβ42/40 positivity on risk of progression to Aβ PET positivity, and feasibility of using plasma Aβ42/40 tests to enrich a primary prevention trial. A prospective longitudinal cohort study. Participants of Australian Imaging, Biomarkers and Lifestyle study (AIBL), Alzheimer's Disease Neuroimaging Initiative (ADNI), and Open Access Series of Imaging Studies 3 (OASIS3). 507 cognitively unimpaired adults at baseline, with a baseline Aβ PET < 20 Centiloid (CL) and available longitudinal Aβ PET data. Baseline Aβ PET and plasma Aβ42/40 measurement by mass-spectrometry, followed by 1-6 additional Aβ PET scans every 1.5-3 years. Those < 5 CL were classified as PET- and 5-20 CL as PET At baseline, 283 were Plasma-/PET-, 97 Plasma+/PET-, 76 Plasma-/PET Cognitively unimpaired individuals with abnormal Aβ42/40 are at increased risk for future Aβ PET positivity. In the 5-20 CL subgroup, baseline CL is the main driver of this risk. Combining blood-based pre-screening with PET imaging may help efficiently enrich primary prevention trials. Show less

Lecanemab is an anti-amyloid monoclonal antibody, recently approved in the UK as a treatment for mild cognitive impairment (MCI) and mild dementia due to Alzheimer's disease (AD) in adults who are apolipoprotein E ε4 gene ( Show less

Alzheimer's disease (AD) is the leading cause of dementia and is often prefaced by mild cognitive impairment (MCI). Detection of AD-related changes via blood-based biomarkers would enable critical therapeutic interventions early in disease progression. Neuronal enriched extracellular vesicle (NEEV) miRNAs regulate peripheral genes as a response to early AD brain changes and hence may have biomarker potential. Plasma NEEVs were captured from plasma samples of Mexican Americans (MAs) and Non-Hispanic Whites (NHWs) using an antibody against the neuronal surface marker CD171. miRNAs isolated from NEEVs were sequenced and analyzed using miRDeep2/DEseq2 and QIAGEN RNA-seq portal for differential expression between cognitively impaired (CI) and cognitively unimpaired controls. hsa-miR-122-5p was significantly underrepresented in the CI group in both MAs and NHWs compared to the healthy control. Other population-specific miRNAs (MAs: hsa-miR-26a-5p, hsa-let-7f-5p, and hsa-miR-139-5p, NHWs: hsa-miR-133a-3p, hsa-miR-125b-5p, and hsa-miR-100-5p) identified may have biomarker potential in AD precision medicine. Some of these differentially expressed miRNAs were associated with key AD-related comorbidities such as APOE genotype, age, and metabolic burden and were predicted to target genes within NF-κB -regulated inflammatory pathways. Together, these findings suggest that dysregulated miRNA networks may serve as a mechanistic link between comorbidity burden and AD-related neuroinflammation and neurodegeneration. Show less

The profile of autoantibodies is dysregulated in patients with Alzheimer's disease (AD). Autoantibodies to beta-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) are present in human blood. This study aims to investigate the clinical relevance and pathophysiological roles of autoantibodies to BACE1 in AD. Clinical investigations were conducted in two independent cohorts, the Chongqing cohort, and the Australian Imaging, Biomarkers, and Lifestyle (AIBL) cohort. The Chongqing cohort included 55 AD patients, 28 patients with non-AD dementia, and 70 cognitively normal subjects (CN). The AIBL cohort included 162 Aβ-PET Show less

Neuronal ceroid lipofuscinosis is a group of neurodegenerative disorders with varying visual dysfunction. CLN3 is a subtype which commonly presents with visual decline. Visual symptomatology can be indistinct making early diagnosis difficult. This study reports ocular biomarkers of CLN3 patients to assist clinicians in early diagnosis, disease monitoring, and future therapy. Retrospective review of 5 confirmed CLN3 patients in our eye clinic. Best corrected visual acuity (BCVA), electroretinogram (ERG), ultra-widefield (UWF) fundus photography and fundus autofluorescence (FAF), and optical coherence tomography (OCT) studies were undertaken. Five unrelated children, 4 females and 1 male, with median age of 6.2 years (4.6-11.7) at first assessment were investigated at the clinic from 2016 to 2021. Four homozygous and one heterozygous pathogenic CLN3 variants were found. Best corrected visual acuities (BCVAs) ranged from 0.18 to 0.88 logMAR at first presentation. Electronegative ERGs were identified in all patients. Bull's eye maculopathies found in all patients. Hyper-autofluorescence ring surrounding hypo-autofluorescence fovea on FAF was found. Foveal ellipsoid zone (EZ) disruptions were found in all patients with additional inner and outer retinal microcystic changes in one patient. Neurological problems noted included autism, anxiety, motor dyspraxia, behavioural issue, and psychomotor regression. CLN3 patients presented at median age 6.2 years with visual decline. Early onset maculopathy with an electronegative ERG and variable cognitive and motor decline should prompt further investigations including neuropaediatric evaluation and genetic assessment for CLN3 disease. The structural parameters such as EZ and FAF will facilitate ocular monitoring. Show less

To identify gene expression patterns and interaction networks related to BCR-ABL status and clinical outcome in adults with acute lymphoblastic leukemia (ALL). DNA microarrays were used to profile a set of 54 adult ALL specimens from the Medical Research Council UKALL XII/Eastern Cooperative Oncology Group E2993 trial (21 p185BCR-ABL-positive, 16 p210BCR-ABL-positive and 17 BCR-ABL-negative specimens). Using supervised and unsupervised analysis tools, we detected significant transcriptomic changes in BCR-ABL-positive versus -negative specimens, and assessed their validity in an independent cohort of 128 adult ALL specimens. This set of 271 differentially expressed genes (including GAB1, CIITA, XBP1, CD83, SERPINB9, PTP4A3, NOV, LOX, CTNND1, BAALC, and RAB21) is enriched for genes involved in cell death, cellular growth and proliferation, and hematologic system development and function. Network analysis demonstrated complex interaction patterns of these genes, and identified FYN and IL15 as the hubs of the top-scoring network. Within the BCR-ABL-positive subgroups, we identified genes overexpressed (PILRB, STS-1, SPRY1) or underexpressed (TSPAN16, ADAMTSL4) in p185BCR-ABL-positive ALL relative to p210BCR-ABL-positive ALL. Finally, we constructed a gene expression- and interaction-based outcome predictor consisting of 27 genes (including GRB2, GAB1, GLI1, IRS1, RUNX2, and SPP1), which correlated with overall survival in BCR-ABL-positive adult ALL (P = .0001), independent of age (P = .25) and WBC count at presentation (P = .003). We identified prominent molecular features of BCR-ABL-positive adult ALL, which may be useful for developing novel therapeutic targets and prognostic markers in this disease. Show less