👤 Henrik Zetterberg

Cerebrospinal fluid amyloid beta 42, total tau, and phosphorylated tau 181 are well accepted markers of Alzheimer's disease. These biomarkers better reflect disease pathogenesis compared to clinical diagnosis. Here, we perform a genome wide association study meta-analysis including 18,948 individuals of European ancestry and identify 12 genome-wide significant loci across all three biomarkers, eight of them novel. We replicate the association of biomarkers with APOE, CR1, GMNC/CCDC50 and C16orf95/MAP1LC3B. Novel loci include BIN1 for amyloid beta and GNA12, MS4A6A, SLCO1A2 with both total tau and phosphorylated tau 181, as well as additional loci on chr. 8, near ANGPT1 and chr. 9 near SMARCA2. We also demonstrate that these variants have significant association with Alzheimer's disease risk, disease progression and/or brain amyloidosis. The associated genes are implicated in lipid metabolism independent of APOE, coupled with autophagy and brain volume regulation driven by total tau and phosphorylated tau 181 dysregulation. Show less

To determine whether long-term residential air pollution [AP; ozone (O₃) and fine particulate matter (PM₂.₅)] is associated with (1) incident mild cognitive impairment (MCI) or Alzheimer’s disease (AD), (2) biomarkers of core and AD-relevant pathology, and (3) whether these relationships are moderated by APOE4+/- (carrier/non-carrier of one or both ε4 alleles) status or mediated by neuroinflammation. Sample included 795 participants (Mage 68.7 ± 7.9; 68% female) from the Wisconsin Alzheimer’s Disease Research Center and Wisconsin Registry for Alzheimer’s Prevention parent studies, both enriched for AD risk at enrollment based on parental AD history. Residential zip code and 2009–2021 EPA-based annual AP reports were used to estimate individual exposure. Cox proportional hazards models assessed MCI/AD risk. Linear regressions examined the relationships between AP exposure and biomarkers of core and AD-relevant pathology, with and without APOE4 + stratification. Causal mediation analysis examined whether markers of inflammation mediated the AP-AD pathology relationships. Neither O₃ nor PM₂.₅ exposure predicted MCI/AD incidence nor core AD pathology (Ps > 0.05). Higher PM₂.₅ was associated with higher CSF GFAP levels ( Show less

The apolipoprotein E (APOE) gene ε4 allele leads to increased Alzheimer disease risk and neuroinflammation and is also believed to play a role in postoperative delirium. However, the safety and feasibility of modulating apoE protein signaling to reduce postoperative neuroinflammation and delirium in older adults are unclear. To assess the safety and feasibility of the apoE mimetic peptide CN-105 for reducing delirium incidence and severity and neuroinflammation after noncardiac or nonintracranial surgery in older adults. This triple-blind, escalating dose, phase 2 randomized clinical trial enrolled patients from April 17, 2019, to December 28, 2022, at a tertiary academic medical center. Included patients were 60 years or older and scheduled for a noncardiac or nonintracranial surgery. Exclusion criteria were incarceration, planned chemotherapy within 6 weeks after surgery, or inability to undergo lumbar punctures. Data analyses were based on a modified intention-to-treat approach and were performed from August 14, 2023, to August 22, 2025. Patients were randomly assigned 3:1 to the CN-105 group or placebo group. The CN-105 group received intravenous CN-105 doses of 0.1, 0.5, or 1 mg/kg starting within 1 hour before surgery and administered every 6 hours afterward until hospital discharge or 13 doses were received. Patients in the placebo group followed the same administration schedule. The primary outcome was safety-the incidence and number of postoperative adverse events (AEs). Secondary outcomes included feasibility (rate of drug doses administered within 90 minutes of schedule), postoperative delirium incidence and severity, and postoperative changes in cerebrospinal fluid (CSF) cytokine levels (interleukin [IL] 6, granulocyte-colony stimulating factor [G-CSF], monocyte chemoattractant protein-1 [MCP-1], and IL-8). Among 203 enrolled patients, 186 (mean [SD] age, 68.7 [5.2] years; 119 males [64.0%]) were randomized (137 to the CN-105 group, 49 to the placebo group) and underwent surgery. The rates of grade 2 or higher AEs among patients in the CN-105 and placebo groups were 76.6% and 87.8% (relative risk [RR], 0.87; 95% CI, 0.76-1.00; P = .10). The CN-105 vs placebo group had fewer grade 2 or higher AEs per patient (median [IQR], 1 [1-3] vs 2 [1-5]; P = .03). The percentage of CN-105 doses administered within the time window was 94.6% (860 of 909; 95% CI, 92.9%-96.0%) in the CN-105 group and 93.8% (346 of 369; 95% CI, 90.8%-96.0%) in the placebo group. Among patients in the CN-105 vs placebo group, the postoperative delirium incidence was 19.3% vs 26.5% (odds ratio [OR], 0.66; 95% CI, 0.31-1.42; P = .29); the median (IQR) postoperative delirium severity scores were 1 (1-2) vs 2 (1-2) (P = .19); and the median difference in preoperative to 24-hour postoperative CSF cytokine-level changes were as follows: -0.39 pg/mL (95% CI, -0.93 to 0.14 pg/mL, P = .12) for IL-6, -0.84 pg/mL (95% CI, -3.06 to 1.40 pg/mL; P = .18) for G-CSF,-23.32 pg/mL (95% CI, -94.36 to 44.93 pg/mL; P = .57) for IL-8, and -2.36 pg/mL (95% CI, -58.57 to 58.62 pg/mL; P = .50) for MCP-1. In this phase 2 randomized clinical trial of older surgical patients, CN-105 (vs placebo) administration was feasible and did not increase AEs. A phase 3 trial is warranted to further evaluate the efficacy of CN-105 for reducing postoperative AEs and to more precisely determine its effects on postoperative delirium incidence and severity. ClinicalTrials.gov Identifier: NCT03802396. Show less

BackgroundInterpreting blood-based biomarkers of Alzheimer's disease and related dementias (ADRD) in a multicultural cohort is complicated by inconsistent evidence on racial differences. Kidney function, which varies by race and influences biomarker levels, is often overlooked, potentially contributing to these inconsistencies.ObjectiveTo characterize racial differences in plasma levels of ADRD biomarkers after adjusting for comorbidities and assessed the impact of estimated glomerular filtration rate (eGFR) adjustment using either race-specific or race-neutral equations.MethodsData from the Einstein Aging Study, a multicultural cohort of older adults, included plasma biomarkers (Aβ Show less

Subjective cognitive complaints (SCC) can precede cognitive decline and are associated with demographic, exposure, lifestyle, and psychological factors. Prevalences of SCC and their correlates in individuals with repetitive head impacts (RHI) are poorly understood. This study characterized SCC in former elite American football players by frequency, mood and behavioral correlates, concordance with informant reports, and associations with neuropsychological test performance, cerebrospinal fluid (CSF), and magnetic resonance imaging (MRI) markers of neurodegeneration. Former American football players ( Rates of SCC ranged from 43 to 77% depending on the domain. Symptoms of depression, impulsivity, and anxiety were strongly associated with SCC. Self- and informant-reported SCC showed moderate inter-rater agreement. Adjusting for age, race, education, SCC are strongly associated with neuropsychiatric factors in former American football players. SCC may also be a marker of cognitive decline and neurodegeneration. Show less

Microglia, the resident immune cells of the central nervous system (CNS), play a pivotal role in health and disease maintaining homeostasis and mediating neuroinflammatory responses. Their activation is a dynamic and context-dependent process characterized by diverse phenotypic states defined by transcriptomic, proteomic, and morphological characteristics. While lipopolysaccharide (LPS) is widely used as an inflammatory stimulus in microglial research, its physiological relevance remains debated. Interferon gamma (IFNγ), a key pro-inflammatory cytokine involved in immune priming, more closely mimics CNS inflammatory conditions. In this study, we systematically investigated the temporal activation profiles of human iPSC-derived microglia (hiMG) in response to LPS, IFNγ, and their combination. Transcriptomic analysis at 24 h revealed robust differential gene expression, with over 7,000 genes altered by LPS and more than 8,500 by LPS/IFNγ co-stimulation. These profiles partially overlapped with disease-associated microglia (DAM) signatures, including upregulation of Show less

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with exposure to repetitive head impacts (RHIs), characterized by tau tangles around small blood vessels at the depths of the sulci. Currently, CTE can be diagnosed only Show less

Vascular damage, including cerebral amyloid angiopathy (CAA) and non-amyloid cerebral small vessel disease (CSVD), has been linked to glymphatic dysfunction, which may contribute to Alzheimer's disease (AD) pathology and cognitive decline. We investigated the associations among vascular damage, glymphatic function measured by the DTI-ALPS (Diffusion Tensor Imaging-Analysis Along the Perivascular Space) index, AD plasma biomarkers, and cognitive decline. This study includes 1,249 participants recruited from Samsung Medical Center. We performed linear regression analysis to identify factors associated with the DTI-ALPS index. Further, linear regression analysis with vascular imaging markers, including CAA and CSVD summary scores, as predictors and DTI-ALPS index as an outcome was performed to investigate the effect of vascular pathology on glymphatic function. We conducted mediation analyses to investigate whether the DTI-ALPS index mediates the effect of vascular imaging markers on plasma biomarkers (phosphorylated tau 217 [p-tau 217], glial fibrillary acidic protein [GFAP], and neurofilament light chain [NFL]). Additionally, mediation analyses with the DTI-ALPS index as a predictor, each plasma biomarker as a mediator, and annual MMSE or CDR-SOB change as an outcome to investigate whether plasma biomarkers mediate the effect of the DTI-ALPS index on longitudinal cognitive decline. First, the DTI-ALPS index was negatively associated with both CAA (β [95% CI] = -0.163 [-0.214, -0.112], p < 0.0001) and CSVD (β [95% CI] = -0.195 [-0.247, -0.143], p < 0.0001) summary scores after controlling for age, sex, BMI status, and APOE genotype. Second, the DTI-ALPS index fully mediated the relationship between these vascular markers and p-tau 217 (CSVD summary score, indirect effect β [95% CI] = 0.016 [0.010, 0.023], p < 0.001; CAA summary score, indirect effect β [95% CI] = 0.013 [0.008, 0.020], p < 0.001) and GFAP (CSVD summary score, indirect effect β [95% CI] = 0.015 [0.008, 0.022], p < 0.001; CAA summary score, indirect effect β [95% CI] = 0.012 [0.007, 0.019], p < 0.001), while partially mediating the relationship for NFL, regardless of Aβ uptake on PET. Finally, the DTI-ALPS index was significantly associated with cognitive decline and this association was partially mediated by plasma biomarkers. These findings highlight glymphatic dysfunction as a key mechanism linking vascular pathology with tau, inflammation and neurodegeneration, independent of Aβ uptakes. Show less

Autosomal dominant Alzheimer's disease (ADAD) serves as a model for presymptomatic biomarker discovery. Characterising the temporal profile of plasma biomarker levels in presymptomatic individuals may enhance understanding of disease pathogenesis, inform future clinical trials, and guide clinical interpretation. We evaluated 124 proteins using a NUcleic acid-Linked Immuno-Sandwich Assay (NULISA) panel in 270 plasma samples from a longitudinal cohort study of ADAD, comprising 113 individuals (73 mutation carriers and 40 non-carriers). We determined the plasma proteomic changes that distinguished mutation carriers from non-carriers. We then used predicted age at symptom onset to determine the approximate timing of presymptomatic divergence in biomarker levels in carriers relative to non-carriers. Nine proteins (Aβ42, BACE1, GFAP, pTau181, pTau231, pTau217, MAPT, NfL, and AChE) robustly differed between carriers and non-carriers, cross-sectionally. Longitudinal analyses showed Aβ42 levels were elevated in carriers at least 26 years before expected symptom onset. Carriers diverged from non-carriers in phosphorylated tau markers at 21-24 years before expected symptoms, total-tau at 19 years, GFAP and BACE1 at 14 years, and NfL at 6 years. Differences in AChE were seen in symptomatic individuals, likely reflecting cholinesterase inhibitor use. Multiple plasma proteins are elevated in presymptomatic and symptomatic autosomal dominant AD mutation carriers relative to non-carriers. Changes in eight biomarkers occur sequentially from 26 to 6 years prior to symptom onset. Combining biomarkers may help in staging presymptomatic AD and optimise clinical trial inclusion. Further work is needed to assess how these findings generalise to non-monogenic AD. The molecular pathology of Alzheimer's disease develops many years before the onset of symptoms, and multiple plasma biomarkers of Alzheimer's pathology have been identified. Understanding the timing of biomarker abnormality is important to guide trial design for the timing of interventions to prevent the onset of dementia. Using an autosomal dominant Alzheimer's disease cohort, we identify multiple plasma biomarkers that distinguish mutation carriers from non-carrier familial controls and characterise the timing of these changes relative to symptom onset. We demonstrate that biomarkers show change many years before symptom onset: markers of abnormal tau phosphorylation more than 20 years prior, followed by markers of reactive astrocytosis and synaptic dysfunction approximately 15 years prior, and neurodegenerative markers within 10 years of symptoms. Plasma biomarkers could be used in pre-clinical autosomal dominant Alzheimer's disease to chart disease trajectories and predict symptom onset, allowing targeted disease-modifying therapy implementation and optimised clinical trial design. Show less

Contact sports, including rugby union, are associated with higher rates of neurodegenerative dementia, due to various underlying pathologies such as Alzheimer's disease (AD) and chronic traumatic encephalopathy (CTE). New ultrasensitive multiplexed immunoassays may clarify disease mechanisms after repetitive head impacts (RHI) and traumatic brain injury, potentially aiding risk-stratification, early diagnosis and dementia treatment. Midlife participants in the ABHC cohort underwent plasma biomarker quantification (NULISA - NUcleic acid Linked Immuno-Sandwich Assay; n=124 markers), 3T MRI, trauma exposure ascertainment and phenotyping. Regressions quantified exposure-specific protein expression, relationship to trauma (including position) and brain atrophy, using cluster analysis to test correlates of traumatic encephalopathy syndrome (TES). 197 former elite rugby players and 33 controls were assessed. 24 (12.2%) met criteria for TES but none had dementia. Ex-players returned reduced plasma glial fibrillary acidic protein (GFAP), kallikrein-6 (KLK6) and synaptosomal-associated protein 25 (SNAP25). Ex-forwards specifically showed reduced plasma beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), amyloid beta-38 (Aβ38), and increased phospho-tau Ex-players showed distinctive plasma biomarker changes, more prominently in ex-forwards, possibly reflecting greater RHI exposure. Plasma KLK6, an endothelial serine protease, was reduced across the ex-player group, with potential diagnostic or prognostic utility in future. Reduced GFAP and SNAP25 in ex-forwards has an uncertain basis, while elevated p-tau- Show less

It is unclear whether the different Alzheimer's disease (AD) progression trajectories of apolipoprotein E (APOE) ɛ4 carriers is reflected by blood phosphorylated tau (p-tau) analytes. We assessed longitudinal trajectories in plasma p-tau181, 217, and 231, in amyloid beta-positive (A+) and negative (A-) APOE ɛ4 carriers (E+) or non-carriers (E-). We included 2039 participants from the observational Translational Biomarkers in Aging and Dementia (TRIAD) and Alzheimer's Disease Neuroimaging Initiative cohorts, categorized into 840 A-E-, 251 A-E+, 386 A+E4-, and 616 A+E4+. Longitudinal data were available for 1045 participants. In TRIAD, ALZpath p-tau217 (β = 0.45, p = 0.02) and p-tau217+ These findings suggest p-tau217 as a marker of faster progression in APOE ɛ4 carriers, highlighting its potential in disease stratification. Blood phosphorylated tau (p-tau)217 increases faster in apolipoprotein E (APOE) ɛ4 carriers with amyloid pathology. p-tau181 and p-tau231 do not increase faster in APOE ɛ4 carriers. APOE ɛ4 carriership does not change p-tau in individuals without amyloid pathology. Show less

Neuroprotective properties of estrogen have poorly translated to reduced neurodegeneration in clinical trials of systemic estrogen replacement therapy. To more directly assess biological processes associated with brain estrogen (estrone, estradiol) levels, we recruited 81 women (42 non-white) and 28 men (13 non-white) for cerebrospinal fluid (CSF) hormone, targeted proteomic, and volumetric brain analysis. In the mostly post-menopausal women, we found CSF estrogen levels to only modestly correlate with their corresponding plasma levels, and were additionally influenced by body mass index or age. CSF estrone was also correlated with a marker of Alzheimer’s disease (AD) neuropathologic change (CSF Aβ42/Aβ40), but this was not the case for the more biologically active CSF estradiol. Aptamer-based proteomic analysis of 1,075 CSF markers for inflammation, proteolysis, signaling, and DNA/RNA regulation revealed CSF estrogen levels to associate with alternative complement pathway proteins, and shifts observed in AD (apoE, RAGE). Parallel MRI analysis correlated higher CSF estrogen with smaller volumes of the brain somatosensory and posterior-medial networks without influence from cognition or neurodegeneration. Analysis using plasma estrogens only partially reproduced CSF estrogens’ biochemical correlates but provided inconclusive relationships with brain volume correlates. These findings highlight the association between CSF levels of the more biologically active estradiol and CSF inflammatory pathways involving AD risk genes as potential mechanisms linking hormone status to AD risks, and suggest caution in using CSF estrone or plasma estrogens when interpreting treatment or preventive studies. The online version contains supplementary material available at 10.1186/s12974-025-03657-3. Show less

We test the hypothesis that high levels of neuroplasticity in the context of Alzheimer's disease (AD) risk factors are involved in AD pathogenesis by investigating interactions between cerebrospinal fluid (CSF) levels of growth-associated protein-43 (GAP-43) and AD risk factors (female sex, cerebrovascular risk, mild cognitive impairment, apolipoprotein E [APOE] ε4 genotype, amyloid positivity) on CSF biomarkers of AD pathology (amyloid beta 42/40[Aβ42/40], phosphorylated tau (p-tau)) and neurodegeneration (tau). Baseline GAP-43 levels in 161 non-demented older adults were related to cross-sectional and longitudinal (mean follow-up = 4 years) CSF biomarkers of AD, adjusting for covariates, with GAP-43 x AD risk factor interaction terms. Higher GAP-43 was cross-sectionally related to all AD biomarkers (p-values < 0.0001) and predicted longitudinal reductions in Aβ42 (p < 0.0001). Associations were stronger in AD risk groups. We found strong support linking increased levels of neuroplasticity in the context of AD risk factors to the pathological cascade of AD over a 4-year mean follow-up period. Cerebrospinal fluid growth-associated protein-43 (GAP-43) is associated with Alzheimer's disease (AD) biomarkers cross-sectionally and longitudinally. GAP-43 interacts with AD risk factors to predict AD biomarkers. Increased neuroplastic activity may play a role in AD pathogenesis. Show less

Biomarker profiling from biofluids such as blood are widely measured in clinical research, using for example Olink proteomics panels. One such research focus area is cardiovascular disease (CVD), for which chronic sleep restriction (SR) is a risk factor. However, it remains unclear whether blood levels of commonly measured CVD biomarkers are sensitive to acute dynamic factors such as SR, physical exercise (PEx), and time of day. In this crossover design, 16 normal-weight, healthy men underwent three highly standardized in-lab nights of SR (4.25 h/night) and normal sleep (NS, 8.5 h/night) in randomized order, with 88 CVD blood protein biomarkers quantified using the Olink technology (and selected validation using ELISA) in the morning, evening, and immediately before and repeatedly after 30 min of high-intensity exercise. We found significant time-of-day-dependent changes in several CVD biomarkers. Whereas several proteins were exercise-induced across sleep conditions (such as the canonical exerkines IL- 6 and BDNF), exercise-induced proteomic dynamics differed in response to recurrent SR, compared with following NS. Moreover, SR compared with NS resulted in a biomarker profile previously associated with increased prospective risk of several CVDs across large-scale cohorts (such as higher circulating levels of IL-27 and LGALS9). Our findings highlight how dynamic physiology can modulate CVD biomarker levels. These results also underscore the need to consider sleep duration as a key determinant of cardiovascular health-an emphasis reflected in recent American Heart Association guidelines. Further studies in women, older individuals, and patients with prior CVD, and across different chronotypes and dietary schedules are warranted. Show less

High-throughput quantitative analysis of protein conformational changes has a profound impact on our understanding of the pathological mechanisms of Alzheimer's disease (AD). To establish an effective workflow enabling quantitative analysis of changes in protein conformation within multiple samples simultaneously, here we report the combination of Show less

Alzheimer's disease (AD) is characterized pathologically by amyloid β (Aβ)-containing plaques. Generation of Aβ from amyloid precursor protein (APP) by two enzymes, β- and γ-secretase, has therefore been in the AD research spotlight for decades. Despite this, how the physical interaction of APP with the secretases influences APP processing is not fully understood. Herein, we compared two genetically identical human iPSC-derived neuronal cell types: low Aβ-secreting neuroprogenitor cells (NPCs) and high Aβ-secreting mature neurons, as models of low versus high Aβ production. We investigated levels of substrate, enzymes and products of APP amyloidogenic processing and correlated them with the proximity of APP to β- and γ-secretase in endo-lysosomal organelles. In mature neurons, increased colocalization of full-length APP with the β-secretase BACE1 correlated with increased β-cleavage product sAPPβ. Increased flAPP/BACE1 colocalization was mainly found in early endosomes. In the same way, increased colocalization of APP-derived C-terminal fragment (CTF) with presenilin-1 (PSEN1), the catalytic subunit of γ-secretase, was seen in neurons as compared to NPCs. Furthermore, most of the interaction of APP with BACE1 in low Aβ-secreting NPCs seemed to derive from CTF, the remaining APP part after BACE1 cleavage, indicating a possible novel product-enzyme inhibition. In conclusion, our results suggest that interaction of APP and APP cleavage products with their secretases can regulate Aβ production both positively and negatively. β- and γ-Secretases are difficult targets for AD treatment due to their ubiquitous nature and wide range of substrates. Therefore, targeting APP-secretase interactions could be a novel treatment strategy for AD. Colocalization of APP species with BACE1 in a novel model of low- versus high-Aβ secretion-Two genetically identical human iPSC-derived neuronal cell types: low Aβ-secreting neuroprogenitor cells (NPCs) and high Aβ secreting mature neurons, were compared. Increased full-length APP (flAPP)/BACE1 colocalization in early endosomes was seen in neurons, while APP-CTF/BACE1 colocalization was much higher than flAPP/BACE1 colocalization in NPCs, although the cellular location was not determined. Show less