Baseline Cerebrospinal Fluid Research Articles

Association of CSF soluble TREM1 levels with hippocampal atrophy in cognitively impaired older adults

BackgroundRecent studies have shown that cerebrospinal fluid (CSF) levels of soluble triggering receptor expressed on myeloid cells 1 (sTREM1) are elevated in individuals with Alzheimer’s disease (AD), though the relationship between CSF sTREM1 and hippocampal atrophy remains to be elucidated. The primary aim of this study was to investigate the association between CSF sTREM1 levels and longitudinal changes in hippocampal volumes, and to determine if this relationship is moderated by cognitive status.MethodsWe included 576 participants, comprising 152 cognitively unimpaired (CU) and 424 cognitively impaired (CI) individuals. In the cross-sectional analyses, Pearson’s correlation tests were conducted to examine the relationship between baseline CSF sTREM1 levels and hippocampal volumes in both CU and CI participants. For the longitudinal analyses, a linear mixed-effects model was employed to assess the significance of the three-way interaction between CSF sTREM1 levels, cognitive status, and follow-up time on adjusted hippocampal volume (aHV). Further stratified analyses based on cognitive status were performed to dissect the specific effects within each group.ResultsOur findings revealed significantly elevated baseline CSF sTREM1 levels in CI participants compared to CU participants. Cross-sectional analyses demonstrated that CSF sTREM1 levels were negatively associated with hippocampal volumes in both CU and CI participants. In the longitudinal analyses, the three-way interaction between CSF sTREM1 levels, cognitive status, and follow-up time was found to be significant for aHV. Stratified analyses indicated that, in CI participants, higher CSF sTREM1 levels were associated with a more accelerated rate of hippocampal atrophy, whereas no such association was observed in CU participants.ConclusionThese results underscore the complex interplay between neuroinflammation, as reflected by CSF sTREM1 levels, hippocampal atrophy, and cognitive decline. The data suggest that neuroinflammation may contribute differently to hippocampal atrophy rates in CI versus CU individuals, highlighting the potential for targeted anti-inflammatory interventions in the prevention and treatment of AD.

Brain aging rejuvenation factors in adults with genetic and sporadic neurodegenerative disease.

The largest risk factor for dementia is age. Heterochronic blood exchange studies have uncovered age-related blood factors that demonstrate 'pro-aging' or 'pro-youthful' effects on the mouse brain. The clinical relevance and combined effects of these factors for humans is unclear. We examined five previously identified brain rejuvenation factors in cerebrospinal fluid of adults with autosomal dominant forms of frontotemporal dementia and sporadic Alzheimer's disease. Our frontotemporal dementia cohort included 100 observationally followed adults carrying autosomal dominant frontotemporal dementia mutations (Mage = 49.6; 50% female; 43% C9orf72, 24% GRN, 33% MAPT) and 62 non-carriers (Mage = 52.6; 45% female) with cerebrospinal fluid analysed on Somascan, and longitudinal (Mvisits = 3 years, range 1-7 years) neuropsychological and functional assessments and plasma neurofilament light chain. Our Alzheimer's disease cohort included 35 adults with sporadic Alzheimer's disease (Mage = 69.4; 60% female) and 56 controls (Mage = 68.8, 50% female) who completed the same cerebrospinal fluid and clinical outcome measures cross-sectionally. Levels of C-C motif chemokine ligand 11, C-C motif chemokine ligand 2, beta-2-micorglobulin, bone gamma-carboxyglutamate protein (aka Osteocalcin) and colony stimulating factor 2 in cerebrospinal fluid were linearly combined into a composite score, with higher values reflecting 'pro-youthful' levels. In genetic frontotemporal dementia, higher baseline cerebrospinal fluid rejuvenation proteins predicted slower decline across cognitive, functional, and neurofilament light chain trajectories; estimates were similar across genotypes. In transdiagnostic analyses, higher cerebrospinal fluid rejuvenation proteins associated with better functional, cognitive, and neurofilament light chain outcomes in adults with sporadic Alzheimer's disease. Proteins with pre-clinical evidence for brain rejuvenation show translational clinical relevance in adults with Alzheimer's disease and related dementias and warrant further investigation.

Longitudinal associations between cerebrospinal fluid glial activation markers, depression, and dopamine transporter availability in patients with Parkinson's disease.

Depression and decreased dopamine transporter (DAT) availability are prevalent in Parkinson's disease (PD), yet early predictive biomarkers are lacking. This study investigates the longitudinal associations between cerebrospinal fluid (CSF) neuroglial activation markers, sTREM2 and YKL-40, and depression, as well as DAT availability, in PD patients. We analyzed data from 172 PD subjects and 80 matched healthy controls from a large longitudinal study. A generalized linear mixed-effects model assessed the longitudinal associations of CSF sTREM2 and YKL-40 with depression and DAT availability. Causal mediation analysis determined if DAT decline mediated the effects of sTREM2 and YKL-40 on depression. Cross-sectional analysis revealed a negative correlation between CSF sTREM2 and baseline depression scores in PD patients. CSF YKL-40 negatively correlated with baseline left caudate nucleus, left anterior putamen, and right anterior putamen specific binding ratios (SBR). Longitudinally, higher baseline CSF sTREM2 predicted faster depression progression (β = 0.828, p < 0.001) and a rapid decline in right putamen SBR (β = 0.072, p = 0.016). Similarly, higher baseline CSF YKL-40 predicted faster depression progression (β = 0.586, p = 0.004) and a decline in left anterior putamen SBR (β = 0.058, p = 0.035). Causal mediation analysis indicated that baseline CSF sTREM2 accelerated depression progression via its effect on right putamen and right anterior putamen SBR (Indirect effect = 0.103, p = 0.020; Indirect effect = 0.129, p = 0.016). CSF sTREM2 and YKL-40 are effective predictors for depression and DAT decline in PD, suggesting that neuroglial activation-induced dopaminergic neuron apoptosis significantly contributes to depression onset in PD.

Cerebrospinal Fluid Biomarkers of Central Nervous System Inflammation Predict Cortical Decline in Bipolar Disorder and Ventricular Enlargement in Healthy Controls

Introduction: Bipolar disorder has been associated with significant structural brain changes, potentially driven by central nervous system (CNS) inflammation. This study aimed to investigate the relationship between inflammation biomarkers in cerebrospinal fluid (CSF) and longitudinal structural brain changes. Methods: We included 29 individuals with bipolar disorder and 34 healthy controls, analyzing three selected inflammation-related biomarkers – interleukin-6 (IL-6), interleukin-8 (IL-8), and chitinase-3-like protein 1 (YKL-40) – in both blood serum and CSF. Structural brain changes were assessed through magnetic resonance imaging at two timepoints, focusing on cortical thickness of the middle temporal cortex and inferior frontal gyrus, as well as ventricular volume. Results: In healthy controls, baseline CSF levels of YKL-40 predicted ventricular enlargement in both hemispheres. Among individuals with bipolar disorder, higher baseline levels of IL-8 were associated with a decline in cortical thickness in the right and left middle temporal cortex, as well as the right inferior frontal gyrus. No significant associations were observed with serum biomarkers. Conclusions: These findings suggest that CSF IL-8 may contribute to cortical decline in bipolar disorder. The lack of association between serum biomarkers and brain changes highlights the specificity of CNS inflammation in these processes. Additionally, the observed link between CSF YKL-40 and ventricular enlargement in healthy controls may indicate a role of CNS inflammation processes in normal brain aging.

Longitudinal correlation of cerebrospinal fluid GFAP and the progression of cognition decline in different clinical subtypes of Parkinson's disease.

Glial fibrillary acidic protein (GFAP) is an intermediate filament protein expressed mainly in astrocytes of the central nervous system (CNS), a potential biomarker of cognitive decline in Parkinson's disease (PD). The central motor subtypes of PD include tremor-dominant (TD), postural instability and gait disorder (PIGD), and indeterminate subtypes, whose different course of disease requires the development of biomarkers that can predict progression based on motor subtypes. In this study, we aimed to assess the predictive value of cerebrospinal fluid (CSF) GFAP for PD motor subtypes in PD. Two hundred and sixteen PD patients were recruited in our study from the progression markers initiative. Patients were subgrouped into TD, PIGD, and indeterminate subtypes. Longitudinal relationships between baseline CSF GFAP and cognitive function and CSF biomarkers were assessed using linear mixed-effects models. Cox regression was used to detect cognitive progression in TD patients. The baseline and longitudinal increases in CSF GFAP were associated with a greater decline in episodic memory, CSF α-syn, and a greater increase of CSF NfL in TD and TD-male subtypes. Cox regression showed that higher baseline CSF GFAP levels were corrected with a higher risk of developing mild cognitive impairment (MCI) over a 4-year period in the PD with normal cognition (NC) group (adjusted HR = 1.607, 95% CI 1.907-2.354, p = 0.01). CSF GFAP might be a promising predictor of cognition decline in TD.

Serum neurofilament light chain predicts disease severity in axonal variants of acute immune neuropathies: A retrospective monocentric cohort study.

The purpose was to explore the prognostic utility of neurofilament light chain (NfL) in patients with immune-mediated polyradiculoneuropathies (IMPs). This retrospective monocentric study analysed serum and cerebrospinal fluid samples from patients diagnosed with IMP collected prior to treatment initiation. NfL concentrations were correlated with clinical outcomes, including F score and hospitalization duration. Amongst 115 IMP patients tested, baseline cerebrospinal fluid and serum NfL (sNfL) concentrations were higher in acute inflammatory axonal polyradiculoneuropathy (AIAP) than other IMP variants. In the AIAP cohort, a positive correlation was observed between baseline sNfL concentrations, F score and hospitalization duration. Multivariate linear regression analysis further supported the predictive relationship between elevated baseline sNfL concentrations and clinical outcomes. Using receiver operating characteristic analysis, a cut-off value for sNfL of 351 pg/mL was found to predict an F score >3 in AIAP with a sensitivity of 40% and specificity of 81.8%. AIAP patients with sNfL concentrations above this threshold required longer hospitalization (extended by 15 days). Our findings highlight the potential of baseline sNfL as an effective marker for distinguishing between IMP variants and predicting the prognosis of AIAP. Further validation may facilitate translation of sNfL into clinical practice, potentially identifying high-risk patients for tailored treatment approaches.

BIOM-08. LEVERAGING CSF PROTEOMICS TO OPTIMIZE CNS LYMPHOMA MANAGEMENT

Abstract INTRODUCTION Despite exquisite responses to initial therapy for CNS lymphoma (CNSL), relapse is common and overall responses are disappointing compared to other non-CNS diffuse large B-cell lymphomas. Incorporation of multi-agent intraventricular chemotherapy (MAIVC) alongside systemic therapy is novel. Identification of minimally-invasive biomarkers of response to MAIVC are necessary but lacking. The objectives of this study were to 1) identify baseline cerebrospinal fluid (CSF)-based proteomic predictive biomarkers of MAIVC treatment response and 2) identify tumor burden markers for longitudinal monitoring of MAIVC treatment response in CNSL. METHODS A cohort of patients with primary or secondary CNSL that were treated with MAIVC at Penn State Health (2015-2021) was included. Each MAIVC cycle was administered via Ommaya reservoir and included a 2-drug combination comprised of methotrexate, rituximab, cytarabine, etoposide, topotecan, gemcitabine, or thiotepa. Patient-matched CSF was sampled at pre- and post-therapeutic endpoints and profiled using shotgun proteomics. Patients were grouped by treatment response status. Early responders were defined as patients that achieved malignant cell-free CSF within 6 MAIVC cycles, whereas never responders were those patients that i) did not achieve malignant cell-free CSF by endpoint or ii) required salvage surgery or radiation during MAIVC. RESULTS 59 patients were included (21 primary; 38 secondary CNSL) with a median age of 66 years (range 25-90) and median number of MAIVC cycles of 8 (range 2-23). A proteomic-based classifier, comprised of SGCE, LCP1 and AGRN, discriminated between early and never responders with an AUROC of 0.95. Comparison of CSF at baseline (&amp;lt;3 cycles MAIVC) vs. post-treatment (&amp;gt;12 cycles MAIVC) identified H3F3A, YWHAE, LCP1, CA1 and GAPDH as tumor burden biomarkers. CONCLUSION Here we developed a proteomic signature capable of predicting CNSL patient response to MAIVC, with potential to improve clinical decision making. Furthermore, the biomarkers associated with tumor burden represent important indicators of treatment response. Ongoing efforts are underway to evaluate these candidates as actionable therapeutic targets.

CSF complement proteins are elevated in prodromal to moderate Alzheimer's disease patients and are not altered by the anti-tau antibody semorinemab.

Growing evidence suggests a role for neuroinflammation in Alzheimer's disease (AD). We investigated complement pathway activity in AD patient cerebrospinal fluid (CSF) and evaluated its modulation by the anti-tau antibody semorinemab. Immunoassays were applied to measure CSF complement proteins C4, factor B (FB), C3 and their cleavage fragments C4a, C3a, and factor Bb (Bb) in AD patients and a separate cognitively unimpaired (CU) cohort. All measured CSF complement proteins were increased in AD versus CU subjects, with C4a displaying the most robust increase. Finally, semorinemab did not have a significant pharmacodynamic effect on CSF complement proteins. Elevated levels of CSF C4a, C4, C3a, C3, Bb, and FB are consistent with complement activation in AD brains. Despite showing a reduction in CSF soluble tau species, semorinemab did not impact complement protein levels or activity. Further studies are needed to determine the value of complement proteins as neuroinflammation biomarkers in AD. Cerebrospinal fluid (CSF) complement proteins C4a, C3a, Bb, C4, C3, and factor B levels were increased in Alzheimer's disease (AD) patients compared to a separate cognitively unimpaired (CU) cohort. Baseline CSF complement protein levels were correlated with neuro-axonal degeneration and glial activation biomarkers in AD patients. The investigational anti-tau antibody semorinemab did not impact CSF complement protein levels or activity relative to the placebo arm.

Clinical importance of cerebrospinal fluid protein levels in HIV-associated cryptococcal meningitis: Insights from a prospective cohort study in Uganda.

Cerebrospinal fluid (CSF) protein levels exhibit high variability in HIV-associated cryptococcal meningitis; however, its clinical implications remain unclear. We analyzed data from 890 adults with HIV-associated cryptococcal meningitis randomized into two clinical trials in Uganda between 2015 and 2021. CSF protein was grouped into < 100mg/dl (72%, n =641) and ≥ 100mg/dl (28%, n =249). We described baseline clinical variables and 18-week mortality by CSF protein groups. Those with CSF protein ≥ 100mg/dl were more likely to present with Glasgow coma scale score<15 (P < .01), self-reported seizures at baseline (P = .02), higher CD4 T-cell count (P < .001), and higher CSF white blood cells (P < .001). Moreover, those with a baseline CSF protein ≥ 100mg/dl also had a lower baseline CSF fungal burden (P < .001) and a higher percentage of sterile CSF cultures at day 14 (P = .02). Individuals with CSF protein ≥ 100mg/dl demonstrated a more pronounced immune response consisting of upregulation of immune effector molecules, pro-inflammatory cytokines, T-helper cell type 1 and 17 cytokines, and immune-exhaustion marker (P < .05). 18-week mortality risk in individuals with a CSF protein < 100mg/dl was 34% higher (unadjusted Hazard Ratio 1.34; 95% Confidence Interval, 1.05-1.70; P = .02) than those with CSF protein ≥ 100mg/dl. In HIV-associated cryptococcal meningitis, individuals with baseline CSF protein ≥ 100mg/dl more frequently presented with neurological symptoms, higher CSF inflammatory cytokines, reduced fungal burden, and lower mortality risk. The findings underscore the prognostic significance of baseline CSF protein levels in predicting disease severity and mortality risk in cryptococcal meningitis.

Neurofilaments light chains as a diagnostic and predictive biomarker for Tunisian Multiple Sclerosis patients

BackgroundMultiple Sclerosis (MS) course was shown to be more severe among North Africans compared to Caucasians. Validation of prognostic biomarkers of disease activity and severity is a priority in our practice. ObjectiveWe aimed to investigate the association between baseline cerebrospinal fluid (CSF) and serum NfL (sNFL) levels and disease activity and disability accrual in a cohort of Tunisian patients with MS. MethodsA cross-sectional study was conducted, in the department of Neurology of Razi Hospital, including patients diagnosed with MS. Patient's data were retrieved from our local MS database. Blood and CSF sampling were performed at the first visit. sNFL levels were measured using the Enzyme-Linked Immuno-Sorbent Assay (ELISA) sandwich technique. ResultsThree hundred MS patients were enrolled (sex-ratio= 3.05; mean age at MS onset=28.83 years+9.55, mean MS course = 10.21 years+8.96). MS phenotype was predominately relapsing (73%). CSF NfL levels were significantly correlated to the serum ones. NfL concentrations were significantly associated with MS activity (p = 0.012), disease progression (p = 0.001), and higher Multiple Sclerosis Severity Scores (MSSS) (p = 0.0017, r = 0.28). ConclusionsThese results support the value of NfL as a sensitive and clinically meaningful CSF and blood biomarker to evaluate MS activity and outcomes among Tunisian MS patients.

Cerebrospinal Fluid Lactate Levels as a Prognostic Indicator in Patients With Cryptococcal Meningitis Who Are HIV Negative: A Retrospective Cohort Study.

Cryptococcal meningitis (CM) is a severe central nervous system infection. In patients with HIV infections and coexisting CM, elevated baseline cerebrospinal fluid (CSF) lactate levels can predict increased mortality. However, the CSF lactate level's significance in patients with CM who are HIV negative remains unclear, necessitating further investigation to elucidate the potential distinctions and enhance patient management. This study investigated the significance of CSF lactate levels in patients with CM who were HIV negative. This retrospective study utilized data from the clinical databases of patients who underwent lumbar punctures at a medical center in Kaohsiung City, southern Taiwan. Demographic data, CSF lactate levels, routine CSF analyses, and hematologic and neurologic findings were evaluated. The optimal CSF lactate threshold value was determined by the Youden index. This retrospective study included 70 patients with CM, among whom 44 (63%) and 26 (37%) tested negative and positive for HIV, respectively. The group without HIV exhibited higher CSF lactate levels, with an optimal CSF lactate cutoff point of 7.935 mmol/L for predicting 90-day mortality, resulting in significant predictive accuracies (area under the curve, 0.755; sensitivity, 57.1%; specificity, 100%); this value was an independent mortality predictor in patients who were HIV negative. In patients with CM who were HIV negative, CSF lactate levels ≥7.935 mmol/L correlated with higher mortality rates but without statistical significance. All patients with CM who were HIV negative and had CSF lactate levels ≥7.935 mmol/L died within 3 months of admission. Patients with CM who were HIV negative had elevated CSF lactate levels that correlated with adverse outcomes, enabling early identification of high-risk individuals.

MRI Signature of α-Synuclein Pathology in Asymptomatic Stages and a Memory Clinic Population

The lack of an in vivo measure for α-synuclein (α-syn) pathology until recently has limited thorough characterization of its brain atrophy pattern, especially during early disease stages. To assess the association of state-of-the-art cerebrospinal fluid (CSF) seed amplification assays (SAA) α-syn positivity (SAA α-syn+) with magnetic resonance imaging (MRI) structural measures, across the continuum from clinically unimpaired (CU) to cognitively impaired (CI) individuals, in 3 independent cohorts, and separately in CU and CI individuals, the latter reflecting a memory clinic population. Cross-sectional data were used from the Swedish BioFINDER-2 study (inclusion, 2017-2023) as the discovery cohort and the Swedish BioFINDER-1 study (inclusion, 2007-2015) and Alzheimer's Disease Neuroimaging Initiative (ADNI; inclusion 2005-2022) as replication cohorts. All cohorts are from multicenter studies, but the BioFINDER cohorts used 1 MRI scanner. CU and CI individuals fulfilling inclusion criteria and without missing data points in relevant metrics were included in the study. All analyses were performed from 2023 to 2024. Presence of α-syn pathology, estimated by baseline CSF SAA α-syn. The primary outcomes were cross-sectional structural MRI measures either through voxel-based morphometry (VBM) or regions of interest (ROI) including an automated pipeline for cholinergic basal forebrain nuclei CH4/4p (nucleus basalis of Meynert [NBM]) and CH1/2/3. Secondary outcomes were domain-specific cross-sectional cognitive measures. Analyses were adjusted for CSF biomarkers of Alzheimer pathology. A total of 2961 participants were included in this study: 1388 (mean [SD] age, 71 [10] years; 702 female [51%]) from the BioFINDER-2 study, 752 (mean [SD] age, 72 [6] years; 406 female [54%]) from the BioFINDER-1 study, and 821 (mean [SD] age, 75 [8] years; 449 male [55%]) from ADNI. In the BioFINDER-2 study, VBM analyses in the whole cohort revealed a specific association between SAA α-syn+ and the cholinergic NBM, even when adjusting for Alzheimer copathology. ROI-based analyses in the BioFINDER-2 study focused on regions involved in the cholinergic system and confirmed that SAA α-syn+ was indeed independently associated with smaller NBM (β = -0.271; 95% CI, -0.399 to -0.142; P <.001) and CH1/2/3 volumes (β = -0.227; 95% CI, -0.377 to -0.076; P =.02). SAA α-syn+ was also independently associated with smaller NBM volumes in the separate CU (β = -0.360; 95% CI, -0.603 to -0.117; P =.03) and CI (β = -0.251; 95% CI, -0.408 to -0.095; P =.02) groups. Overall, the association between SAA α-syn+ and NBM volume was replicated in the BioFINDER-1 study and ADNI cohort. In CI individuals, NBM volumes partially mediated the association of SAA α-syn+ with attention/executive impairments in all cohorts (BioFINDER-2, β = -0.017; proportion-mediated effect, 7%; P =.04; BioFINDER-1, β = -0.096; proportion-mediated effect, 19%; P =.04; ADNI, β = -0.061; proportion-mediated effect, 20%; P =.007). In this cohort study, SAA α-syn+ was consistently associated with NBM atrophy already during asymptomatic stages. Further, in memory clinic CI populations, SAA α-syn+ was associated with NBM atrophy, which partially mediated α-syn-induced attention/executive impairment.

CSF glial biomarkers are associated with cognition in individuals at risk of Alzheimer's disease.

We examined whether baseline glial markers soluble triggering receptor expressed on myeloid cell 2 (sTREM2), chitinase 3-like protein 1 (YKL-40), and glial fibrillary acidic protein (GFAP) in cerebrospinal fluid (CSF), and plasma GFAP are associated with cognitive change in cognitively unimpaired (CU) individuals at risk of Alzheimer's disease (AD). A total of 353 CU (mean age 60.9 years) participants were included (mean follow-up time 3.28 years). Linear regression models with cognition as outcome were used. We also tested whether amyloid beta (Aβ) status modified these associations. Higher baseline CSF sTREM2 was associated with a positive global cognition (Preclinical Alzheimer's Cognitive Composite) rate of change, and better memory and executive outcomes, independently of AD pathology. Higher baseline plasma GFAP was associated with a decline on attention rate of change. Stratified analyses by Aβ status showed that CSF sTREM2 and YKL-40 were positively associated with executive functioning in amyloid negative (Aβ-) individuals. Our results suggest that a TREM2-mediated microglial response may be associated with better longitudinal cognitive performance. Higher cerebrospinal fluid (CSF) soluble triggering receptor expressed on myeloid cell 2 (sTREM2) relates to better longitudinal cognitive performance. The association between CSF sTREM2 and cognition is independent of Alzheimer's disease (AD) pathology. Targeting microglial reactivity may be a therapeutic strategyfor AD prevention.

CSF formation rate—a potential glymphatic flow parameter in hydrocephalus?

BackgroundStudies indicate that brain clearance via the glymphatic system is impaired in idiopathic normal pressure hydrocephalus (INPH). This has been suggested to result from reduced cerebrospinal fluid (CSF) turnover, which could be caused by a reduced CSF formation rate. The aim of this study was to determine the formation rate of CSF in a cohort of patients investigated for INPH and compare this to a historical control cohort.MethodsCSF formation rate was estimated in 135 (75 ± 6 years old, 64/71 men/women) patients undergoing investigation for INPH. A semiautomatic CSF infusion investigation (via lumbar puncture) was performed. CSF formation rate was assessed by downregulating and steadily maintaining CSF pressure at a zero level. During the last 10 min, the required outflow to maintain zero pressure, i.e., CSF formation rate, was continuously measured. The values were compared to those of a historical reference cohort from a study by Ekstedt in 1978.ResultsMean CSF formation rate was 0.45 ± 0.15 ml/min (N = 135), equivalent to 27 ± 9 ml/hour. There was no difference in the mean (p = 0.362) or variance (p = 0.498) of CSF formation rate between the subjects that were diagnosed as INPH (N = 86) and those who were not (N = 43). The CSF formation rate in INPH was statistically higher than in the reference cohort (0.46 ± 0.15 vs. 0.40 ± 0.08 ml/min, p = 0.005), but the small difference was probably not physiologically relevant. There was no correlation between CSF formation rate and baseline CSF pressure (r = 0.136, p = 0.115, N = 135) or age (-0.02, p = 0.803, N = 135).ConclusionsThe average CSF formation rate in INPH was not decreased compared to the healthy reference cohort, which does not support reduced CSF turnover. This emphasizes the need to further investigate the source and routes of the flow in the glymphatic system and the cause of the suggested impaired glymphatic clearance in INPH.

Neuroimaging biomarkers and CSF sTREM2 levels in Alzheimer’s disease: a longitudinal study

Understanding the exact pathophysiological mechanisms underlying the involvement of triggering receptor expressed on myeloid cells 2 (TREM2) related microglia activation is crucial for the development of clinical trials targeting microglia activation at different stages of Alzheimer’s disease (AD). Given the contradictory findings in the literature, it is imperative to investigate the longitudinal alterations in cerebrospinal fluid (CSF) soluble TREM2 (sTREM2) levels as a marker for microglia activation, and its potential association with AD biomarkers, in order to address the current knowledge gap. In this study, we aimed to assess the longitudinal changes in CSF sTREM2 levels within the framework of the A/T/N classification system for AD biomarkers and to explore potential associations with AD pathological features, including the presence of amyloid-beta (Aβ) plaques and tau aggregates. The baseline and longitudinal (any available follow-up visit) CSF sTREM2 levels and processed tau-PET and Aβ-PET data of 1001 subjects were recruited from the ADNI database. The participants were classified into four groups based on the A/T/N framework: A+ /TN+ , A+ /TN− , A− /TN+ , and A− /TN− . Linear regression analyses were conducted to assess the relationship between CSF sTREM2 with cognitive performance, tau and Aβ-PET adjusting for age, gender, education, and APOE ε4 status. Based on our analysis there was a significant difference in baseline and rate of change of CSF sTREM2 between ATN groups. While there was no association between baseline CSF sTREM2 and cognitive performance (ADNI-mem), we found that the rate of change of CSF sTREM2 is significantly associated with cognitive performance in the entire cohort but not the ATN groups. We found that the baseline CSF sTREM2 is significantly associated with baseline tau-PET and Aβ-PET rate of change only in the A+ /TN+ group. A significant association was found between the rate of change of CSF sTREM2 and the tau- and Aβ-PET rate of change only in the A+ /TN− group. Our study suggests that the TREM2-related microglia activation and their relations with AD markers and cognitive performance vary the in presence or absence of Aβ and tau pathology. Furthermore, our findings revealed that a faster increase in the level of CSF sTREM2 might attenuate future Aβ plaque formation and tau aggregate accumulation only in the presence of Aβ pathology.

Growth-Associated Protein43 and Tensor-Based Morphometry Indices in Mild Cognitive Impairment.

Growth-associated protein 43 (GAP-43) is found in the axonal terminal of neurons in the limbic system, which is affected in people with Alzheimer's disease (AD). We assumed GAP-43 may contribute to AD progression and serve as a biomarker. So, in a two-year follow-up study, we assessed GAP-43 changes and whether they are correlated with tensor-based morphometry (TBM) findings in patients with mild cognitive impairment (MCI). We included MCI and cognitively normal (CN) people with available baseline and follow-up cerebrospinal fluid (CSF) GAP-43 and TBM findings from the ADNI database. We assessed the difference between the two groups and correlations in each group at each time point. CSF GAP-43 and TBM measures were similar in the two study groups in all time points, except for the accelerated anatomical region of interest (ROI) of CN subjects that were significantly greater than those of MCI. The only significant correlations with GAP-43 observed were those inverse correlations with accelerated and non-accelerated anatomical ROI in MCI subjects at baseline. Plus, all TBM metrics decreased significantly in all study groups during the follow-up in contrast to CSF GAP-43 levels. Our study revealed significant associations between CSF GAP-43 levels and TBM indices among people of the AD spectrum.

Plasma Insulin Predicts Early Amyloid-β Pathology Changes in Alzheimer's Disease.

Evidence suggests that type 2 diabetes (T2D) is an independent risk factor for Alzheimer's disease (AD), sharing similar pathophysiological traits like impaired insulin signaling. To test the association between plasma insulin and cerebrospinal fluid (CSF) AD pathology. A total of 304 participants were included in the Alzheimer's Disease Neuroimaging Initiative, assessing plasma insulin and CSF AD pathology. We explored the cross-sectional and longitudinal associations between plasma insulin and AD pathology and compared their associations across different AD clinical and pathological stages. In the non-demented group, amyloid-β (Aβ)+ participants (e.g., as reflected by CSF Aβ42) exhibited significantly lower plasma insulin levels compared to non-demented Aβ-participants (p < 0.001). This reduction in plasma insulin was more evident in the A+T+ group (as shown by CSF Aβ42 and pTau181 levels) when compared to the A-T- group within the non-dementia group (p = 0.002). Additionally, higher plasma insulin levels were consistently associated with more normal CSF Aβ42 levels (p < 0.001) across all participants. This association was particularly significant in the Aβ-group (p = 0.002) and among non-demented individuals (p < 0.001). Notably, baseline plasma insulin was significantly correlated with longitudinal changes in CSF Aβ42 (p = 0.006), whereas baseline CSF Aβ42 did not show a similar correlation with changes in plasma insulin over time. These findings suggest an association between plasma insulin and early Aβ pathology in the early stages of AD, indicating that plasma insulin may be a potential predictor of changes in early Aβ pathology.

Alzheimer's Disease and Small Vessel Disease Differentially Affect White Matter Microstructure.

Alzheimer's disease (AD) and cerebral small vessel disease (cSVD), the two most common causes of dementia, are characterized by white matter (WM) alterations diverging from the physiological changes occurring in healthy aging. Diffusion tensor imaging (DTI) is a valuable tool to quantify WM integrity non-invasively and identify the determinants of such alterations. Here, we investigated main effects and interactions of AD pathology, APOE-ε4, cSVD, and cardiovascular risk on spatial patterns of WM alterations in non-demented older adults. Within the prospective European Prevention of Alzheimer's Dementia study, we selected 606 participants (64.9 ± 7.2 years, 376 females) with baseline cerebrospinal fluid samples of amyloid β1-42 and p-Tau181 and MRI scans, including DTI scans. Longitudinal scans (mean follow-up time = 1.3 ± 0.5 years) were obtained in a subset (n = 223). WM integrity was assessed by extracting fractional anisotropy and mean diffusivity in relevant tracts. To identify the determinants of WM disruption, we performed a multimodel inference to identify the best linear mixed-effects model for each tract. AD pathology, APOE-ε4, cSVD burden, and cardiovascular risk were all associated with WM integrity within several tracts. While limbic tracts were mainly impacted by AD pathology and APOE-ε4, commissural, associative, and projection tract integrity was more related to cSVD burden and cardiovascular risk. AD pathology and cSVD did not show any significant interaction effect. Our results suggest that AD pathology and cSVD exert independent and spatially different effects on WM microstructure, supporting the role of DTI in disease monitoring and suggesting independent targets for preventive medicine approaches.

Phosphorylated neurofilament heavy chain in cerebrospinal fluid and plasma as a Nusinersen treatment response marker in childhood-onset SMA individuals from Serbia.

Biomarkers capable of reflecting disease onset and short- and long-term therapeutic effects in individuals with spinal muscular atrophy (SMA) are still an unmet need and phosphorylated neurofilament heavy chain (pNF-H) holds significant promise. We conducted a longitudinal prospective study to evaluate pNF-H levels in the cerebrospinal fluid (CSF) and plasma of 29 individuals with childhood-onset SMA treated with Nuinersen (SMA type 1: n = 6, 2: n = 17, 3: n = 6). pNF-H levels before and during treatment were compared with the levels of controls (n = 22), patients with Duchenne muscular dystrophy (n = 17), myotonic dystrophy type 1 (n = 11), untreated SMA individuals with chronic type 3 disease (n = 8), and children with presymptomatic SMA (n = 3). SMA type 1 showed the highest mean CSF pNF-H levels before treatment initiation. All Nusinersen-treated individuals (types 1, 2, and 3) showed significantly elevated mean baseline CSF pNF-H compared to controls, which inversely correlated with age at disease onset, age at first dose, disease duration and the initial CHOP INTEND result (SMA type 1 and 2). During 22 months of treatment, CSF pNF-H levels declined during loading doses, stabilizing at reduced levels from the initial maintenance dose in all individuals. Baseline plasma pNF-H levels in type 1 and 2 SMA were significantly increased compared to other cohorts and decreased notably in type 1 after 2 months of treatment and type 2 after 14 months. Conversely, SMA type 3, characterized by lower baseline pNF-H levels, did not show significant fluctuations in plasma pNF-H levels after 14 months of treatment. Our findings suggest that CSF pNF-H levels in untreated SMA individuals are significantly higher than in controls and that monitoring of CSF pNF-H levels may serve as an indicator of rapid short-term treatment response in childhood-onset SMA individuals, irrespective of the subtype of the disease, while also suggesting its potential for assessing long-term suppression of neurodegeneration. Plasma pNF-H may serve as an appropriate outcome measure for disease progression and/or response to treatment in types 1 and 2 but not in type 3. Presymptomatic infants with SMA may show elevated pNF-H levels, confirming early neuronal degeneration.

Emerging Cerebrospinal Fluid Biomarkers of Disease Activity and Progression in Multiple Sclerosis

Biomarkers distinguishing nonrelapsing progressive disease biology from relapsing biology in multiple sclerosis (MS) are lacking. Cerebrospinal fluid (CSF) is an accessible fluid that most closely reflects central nervous system biology. To identify CSF biological measures associated with progressive MS pathobiology. This cohort study assessed data from 2 prospective MS cohorts: a test cohort provided serial CSF, clinical, and imaging assessments in a multicenter study of patients with relapsing MS (RMS) or primary progressive MS (PPMS) who were initiating anti-CD20 treatment (recruitment: 2016-2018; analysis: 2020-2023). A single-site confirmation cohort was used to assess CSF at baseline and long-term (>10 year) clinical follow-up (analysis: 2022-2023). Test-cohort participants initiated standard-of-care ocrelizumab treatment. Confirmation-cohort participants were untreated or received standard-of-care disease-modifying MS therapies. Twenty-five CSF markers, including neurofilament light chain, neurofilament heavy chain, and glial fibrillary acid protein (GFAP); 24-week confirmed disability progression (CDP24); and brain magnetic resonance imaging measures reflecting focal injury, tissue loss, and progressive biology (slowly expanding lesions [SELs]). The test cohort (n = 131) included 100 patients with RMS (mean [SD] age, 36.6 [10.4] years; 68 [68%] female and 32 [32%] male; Expanded Disability Status Scale [EDSS] score, 0-5.5), and 31 patients with PPMS (mean [SD] age, 44.9 [7.4] years; 15 [48%] female and 16 [52%] male; EDSS score, 3.0-6.5). The confirmation cohort (n = 68) included 41 patients with RMS and 27 with PPMS enrolled at diagnosis (age, 40 years [range, 20-61 years]; 47 [69%] female and 21 [31%] male). In the test cohort, GFAP was correlated with SEL count (r = 0.33), greater proportion of T2 lesion volume from SELs (r = 0.24), and lower T1-weighted intensity within SELs (r = -0.33) but not with acute inflammatory measures. Neurofilament heavy chain was correlated with SEL count (r = 0.25) and lower T1-weighted intensity within SELs (r = -0.28). Immune markers correlated with measures of acute inflammation and, unlike GFAP, were impacted by anti-CD20. In the confirmation cohort, higher baseline CSF GFAP levels were associated with long-term CDP24 (hazard ratio, 2.1; 95% CI, 1.3-3.4; P = .002). In this study, activated glial markers (in particular GFAP) and neurofilament heavy chain were associated specifically with nonrelapsing progressive disease outcomes (independent of acute inflammatory activity). Elevated CSF GFAP was associated with long-term MS disease progression.