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INTRODUCTION: Blood biomarkers accurately identify Alzheimer's disease (AD) pathophysiology and axonal injury. We investigated the influence of food intake on AD‐related biomarkers in cognitively healthy, obese adults at high metabolic risk. METHODS: One‐hundred eleven participants underwent repeated blood sampling during 3 h after a standardized meal (postprandial group, PG). For comparison, blood was sampled from a fasting subgroup over 3 h (fasting group, FG). Plasma neurofilament light (NfL), glial fibrillary acidic protein (GFAP), amyloid‐beta (Aβ) 42/40, phosphorylated tau (p‐tau) 181 and 231, and total‐tau were measured via single molecule array assays. RESULTS: Significant differences were found for NfL, GFAP, Aβ42/40, p‐tau181, and p‐tau231 between FG and PG. The greatest change to baseline occurred for GFAP and p‐tau181 (120 min postprandially, p < 0.0001). CONCLUSION: Our data suggest that AD‐related biomarkers are altered by food intake. Further studies are needed to verify whether blood biomarker sampling should be performed in the fasting state. Highlights: Acute food intake alters plasma biomarkers of Alzheimer's disease in obese, otherwise healthy adults.We also found dynamic fluctuations in plasma biomarkers concentration in the fasting state suggesting physiological diurnal variations.Further investigations are highly needed to verify if biomarker measurements should be performed in the fasting state and at a standardized time of day to improve the diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Introduction: Studies have shown that blood biomarkers can differentiate dementia disorders. However, the diagnosis of dementia still relies primarily on cerebrospinal fluid and imaging modalities. The new disease-modifying treatments call for more widely applicable biomarkers., Methods: Plasma samples ( n  = 250) from two mixed memory clinic were included. Participants were divided into amyloid beta positives (Aβ+) and Aβ negatives (Aβ-). Plasma phosphorylated tau (p-tau) 181, p-tau231, Aβ1-42 (Aβ42), Aβ40, Aβ42/Aβ40, glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) were measured by single molecule array., Results: Significant differences were found among cognitively unimpaired, mild cognitive impairment, Alzheimer's disease (AD), and non-AD, and nearly all of the biomarkers were able to predict amyloid status. When combining p-tau181 and p-tau231 they predicted Aβ positivity with an area under the curve (AUC) of 0.75, and when combining all biomarkers an AUC of 0.86 was found., Discussion: This study supports previous findings on plasma biomarkers, even when investigated in a typical clinical setting in a consecutive, heterogeneous, mixed memory clinic., Highlights: This study investigated seven plasma biomarkers in a mixed memory clinic, regardless of amyloid co-pathology or atypical phenotypes.These findings support previous promising results on plasma biomarkers, even when investigated in a heterogeneous population.The combination of phosphorylated tau (p-tau)181 and p-231 performed only slightly worse than a panel of multiple biomarkers, aligning with previous studies.Plasma biomarkers show potential for future applications in primary care, treatment monitoring, and trial selection., Competing Interests: H.Z. has served on scientific advisory boards and/or as a consultant for Abbvie, Acumen, Alector, Alzinova, ALZPath, Amylyx, Annexon, Apellis, Artery Therapeutics, AZTherapies, Cognito Therapeutics, CogRx, Denali, Eisai, LabCorp, Merry Life, Nervgen, Novo Nordisk, Optoceutics, Passage Bio, Pinteon Therapeutics, Prothena, Red Abbey Labs, reMYND, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics, and Wave; has given lectures in symposia sponsored by Alzecure, Biogen, Cellectricon, Fujirebio, Lilly, Novo Nordisk, and Roche; and is a co‐founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program (outside submitted work). KB has served as a consultant and on advisory boards for Acumen, ALZPath, AriBio, BioArctic, Biogen, Eisai, Lilly, Moleac Pte. Ltd, Novartis, Ono Pharma, Prothena, Roche Diagnostics, and Siemens Healthineers; has served on data monitoring committees for Julius Clinical and Novartis; has given lectures, produced educational materials, and participated in educational programs for AC Immune, Biogen, Celdara Medical, Eisai, and Roche Diagnostics; and is a co‐founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program, outside the work presented in this paper. H.S.G., A.H.S., L.G., N.A., S.G.H., M.G., and P.H. report no conflicts of interest. Author disclosures are available in the supporting information., (© 2025 The Author(s). Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals, LLC on behalf of Alzheimer's Association.)

Introduction: Heterozygous mutations in the progranulin gene (GRN) leading to decreased progranulin levels are one of the most frequent causes of inherited frontotemporal dementia (FTD). We evaluated progranulin levels in dried blood spots from capillary finger-stick collection (DBS capillary )., Methods: Paired venous Ethylenediaminetetraacetic acid (EDTA) plasma and DBS capillary samples were collected from each participant with or without pathogenic GRN mutations., Results: DBS capillary progranulin levels in GRN mutation carriers (mean [SD] age, 55 [13] years; n = 16) were reduced compared to non-mutation carriers (64 [11] years; n = 44) (2.38 ng/mL [1.0] vs 4.37 [0.68] ng/mL; U = 42; p < 0.0001, ROC AUC = 0.94 [95% CI: 0.83 to 1.00]) and highly associated with venous plasma levels (R = 0.819; p < 0.001)., Discussion: Progranulin levels can be accurately determined from finger-stick blood samples. This can enable regular and remote monitoring of this protein in FTD therapeutic trials and potentially serve as a first-level screening test for GRN mutations., Highlights: Progranulin levels measured using capillary dried blood spots were significantly reduced in GRN mutation carriers compared to non-mutation carriers. Progranulin levels measured using capillary dried blood spots strongly correlated with levels from venous EDTA plasma. DBS capillary progranulin levels were able to identify GRN mutation carriers with high accuracy. DBS capillary might allow repeated measurements of progranulin levels in a remote and unsupervised setting, circumventing the restrictions of traditional venous blood collection. DBS capillary might be used to assess the biological efficacy of disease-modifying therapies in clinical trials aiming to increase baseline progranulin levels or as a first-level screening for GRN mutations in primary settings., (© 2024 The Author(s). Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Neurofilament light (NfL) concentration in cerebrospinal fluid (CSF) and blood serves as an important biomarker in neurology drug development. Changes in NfL are generally assumed to reflect changes in neuronal damage, while little is known about the clearance of NfL from biofluids. We observed an NfL increase of 3.5-fold in plasma and 5.7-fold in CSF in an asymptomatic individual at risk for genetic prion disease following 6 weeks' treatment with oral minocycline for a dermatologic indication. Other biomarkers remained normal, and proteomic analysis of CSF revealed that the spike was exquisitely specific to neurofilaments. NfL dropped nearly to normal levels 5 weeks after minocycline cessation, and the individual remained free of disease 2 years later. Plasma NfL in dermatology patients was not elevated above normal controls. Dramatically high plasma NfL (>500 pg/mL) was variably observed in some hospitalized individuals receiving minocycline. In mice, treatment with minocycline resulted in variable increases of 1.3- to 4.0-fold in plasma NfL, with complete washout 2 weeks after cessation. In neuron-microglia co-cultures, minocycline increased NfL concentration in conditioned media by 3.0-fold without any visually obvious impact on neuronal health. We hypothesize that minocycline does not cause or exacerbate neuronal damage, but instead impacts the clearance of NfL from biofluids, a potential confounder for interpretation of this biomarker.

Introduction: Blood biomarkers accurately identify Alzheimer's disease (AD) pathophysiology and axonal injury. We investigated the influence of food intake on AD-related biomarkers in cognitively healthy, obese adults at high metabolic risk., Methods: One-hundred eleven participants underwent repeated blood sampling during 3 h after a standardized meal (postprandial group, PG). For comparison, blood was sampled from a fasting subgroup over 3 h (fasting group, FG). Plasma neurofilament light (NfL), glial fibrillary acidic protein (GFAP), amyloid-beta (Aβ) 42/40, phosphorylated tau (p-tau) 181 and 231, and total-tau were measured via single molecule array assays., Results: Significant differences were found for NfL, GFAP, Aβ42/40, p-tau181, and p-tau231 between FG and PG. The greatest change to baseline occurred for GFAP and p-tau181 (120 min postprandially, p < 0.0001)., Conclusion: Our data suggest that AD-related biomarkers are altered by food intake. Further studies are needed to verify whether blood biomarker sampling should be performed in the fasting state., Highlights: Acute food intake alters plasma biomarkers of Alzheimer's disease in obese, otherwise healthy adults. We also found dynamic fluctuations in plasma biomarkers concentration in the fasting state suggesting physiological diurnal variations. Further investigations are highly needed to verify if biomarker measurements should be performed in the fasting state and at a standardized time of day to improve the diagnostic accuracy., (© 2023 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)