Cerebrospinal Fluid Changes Research Articles

Evaluation of cerebrospinal fluid levels for ALOX5, S100B, DEFA1, and GFAP in infectious meningitis.

The aim of this study was to determine how the levels of peptide and protein-based biomarkers in cerebrospinal fluid change in bacterial, tuberculous, and aseptic meningitis, and to determine the success of these agents in distinguishing between different types of infectious meningitis. The levels of arachidonate-5-lipoxygenase, S100 calcium-binding protein B, defensin-α 1, and glial fibrillary acidic protein in cerebrospinal fluid samples from 20 tuberculosis, 40 bacterial, 25 aseptic meningitis patients, and 55 control groups were measured and compared using an enzyme-linked immunosorbent assay. The mean age of the patients was 37.9 ± 14.4 years. The parameter that contributed the most to the differential diagnosis of the infectious meningitis groups was S100 calcium-binding protein B. The S100 calcium-binding protein B levels were significantly higher in the tuberculous meningitis group than in the other groups, and arachidonate-5-lipoxygenase levels were significantly higher in the tuberculous meningitis and bacterial meningitis groups (P < .05). This study showed that cerebrospinal fluid arachidonate-5-lipoxygenase, and S100 calcium-binding protein B levels may differ in bacterial, aseptic, and tuberculous meningitis, and the results obtained may be quite effective as important potential biomarkers in the differential diagnosis of different types of meningitis.

Prognostic Performance of Hematological and Serum Iron and Metabolite Indices for Detection of Early Iron Deficiency Induced Metabolic Brain Dysfunction in Infant Rhesus Monkeys

BackgroundThe current pediatric practice of monitoring for infantile iron deficiency (ID) via hemoglobin (Hgb) screening at one y of age does not identify preanemic ID nor protect against later neurocognitive deficits. ObjectivesTo identify biomarkers of iron-related metabolic alterations in the serum and brain and determine the sensitivity of conventional iron and heme indices for predicting risk of brain metabolic dysfunction using a nonhuman primate model of infantile ID. MethodsSimultaneous serum iron and RBC indices, and serum and cerebrospinal fluid (CSF) metabolomic profiles were determined in 20 rhesus infants, comparing iron sufficient (IS; N = 10) and ID (N = 10) infants at 2 and 4 mo of age. ResultsReticulocyte hemoglobin (RET-He) was lower at 2 wk in the ID group. Significant IS compared with ID differences in serum iron indices were present at 2 mo, but Hgb and RBC indices differed only at 4 mo (P < 0.05). Serum and CSF metabolomic profiles of the ID and IS groups differed at 2 and 4 mo (P < 0.05). Key metabolites, including homostachydrine and stachydrine (4-5-fold lower at 4 mo in ID group, P < 0.05), were altered in both serum and CSF. Iron indices and RET-He at 2 mo, but not Hgb or other RBC indices, were correlated with altered CSF metabolic profile at 4 mo and had comparable predictive accuracy (area under the receiver operating characteristic curve scores, 0.75–0.80). ConclusionsPreanemic ID at 2 mo was associated with metabolic alterations in serum and CSF in infant monkeys. Among the RBC indices, only RET-He predicted the future risk of abnormal CSF metabolic profile with a predictive accuracy comparable to serum iron indices. The concordance of homostachydrine and stachydrine changes in serum and CSF indicates their potential use as early biomarkers of brain metabolic dysfunction in infantile ID.

PICALM Variation Moderates the Relationships of APOE ɛ4 with Alzheimer's Disease Cerebrospinal Biomarkers and Memory Function Among Non-Demented Population.

APOE ɛ4 and PICALM are established genes associated with risk of late-onset Alzheimer's disease (AD). Previous study indicated interaction of PICALM with APOE ɛ4 in AD patients. To explore whether PICALM variation could moderate the influences of APOE ɛ4 on AD pathology biomarkers and cognition in pre-dementia stage. A total of 1,034 non-demented participants (mean age 74 years, 56% females, 40% APOE ɛ4 carriers) were genotyped for PICALM rs3851179 and APOE ɛ4 at baseline and were followed for influences on changes of cognition and cerebrospinal fluid (CSF) AD markers in six years. The interaction effects were examined via regression models adjusting for age, gender, education, and cognitive diagnosis. The interaction term of rs3851179×APOE ɛ4 accounted for a significant amount of variance in baseline general cognition (p = 0.039) and memory function (p = 0.002). The relationships of APOE ɛ4 with trajectory of CSF Aβ42 (p = 0.007), CSF P-tau181 (p = 0.003), CSF T-tau (p = 0.001), and memory function (p = 0.017) were also moderated by rs3851179 variation. APOE ɛ4 carriers experienced slower clinical and pathological progression when they had more protective A alleles of PICALM rs3851179. These findings firstly revealed the gene-gene interactive effects of PICALM with APOE ɛ4 in pre-dementia stage.

A Phase 2a proof‐of‐concept double‐blind, randomized, placebo‐controlled trial of nicotinamide in early Alzheimer’s disease

AbstractBackgroundNicotinamide is a co‐enzyme involved in cellular oxidation‐reduction reactions that can act as an inhibitor of the class III histone deacetylases (HDACs), or sirtuins. HDAC inhibition may have myriad therapeutic pathways, including reducing phosphorylation of tau.MethodWe performed a randomized, placebo‐controlled, Phase 2a proof‐of‐concept trial to evaluate the safety and tolerability of nicotinamide, and its effects on change in cerebrospinal fluid (CSF) levels of tau phosphorylated at threonine 231 (p‐tau231) and other Alzheimer’s disease (AD) biomarkers and clinical measures in participants with early AD (Mild Cognitive Impairment or mild dementia) as confirmed by CSF biomarkers. We tested whether 1500 mg BID nicotinamide was superior to placebo in reducing CSF p‐tau231 (primary outcome), with secondary outcomes of p‐tau181, total tau, amyloid beta 40 (Ab40), Ab42, ADAS‐cog13, ADCS‐ADL‐MCI, and CDR‐SB.ResultArms were well balanced for demographic and clinical characteristics (Table 1). Of 47 participants enrolled, one dropped out prior to treatment initiation and six dropped before completion, 2 in the nicotinamide and 4 in the placebo arm. Nicotinamide was well‐tolerated; adverse events were largely balanced by study arm, with few attributed to treatment. There was no statistically significant benefit of nicotinamide on the primary outcome of change in CSF p‐tau231 (ANCOVA; estimated mean difference in change between arms = 2.06, std. error = 4.03; p = 0.61), although the observed mean decline in CSF p‐tau231 was greater in the nicotinamide arm (‐4.7±14.5) than in the placebo arm (‐2.3±10.6; Table 2). No significant effects of treatment were observed on secondary biomarker outcomes (CSF p‐tau181, Ab40, Ab42, and total tau) in similar models (all p‐values&gt;0.05), although observed mean changes in CSF p‐tau181 (0.4±29.8 vs 10.4±41.8) and total tau (8.4±228.6 vs 60.5±237.5) favored nicotinamide compared to placebo. Nicotinamide was associated with significantly less change on CDR‐SB (MMRM; estimate = ‐1.42, std. error = 0.65; p = 0.03), but not on cognitive (ADAS‐cog; estimate = ‐1.93, std. error = 1.93; p = 0.32) or functional (ADCS‐ADL‐MCI; estimate = ‐3.10, std. error = 1.86; p = 0.10) assessments. No adjustments for multiple comparisons were performed.ConclusionThese results may suggest that nicotinamide warrants further study as a treatment for early AD.

Longitudinal change in CSF β‐amyloid1−42 predicts PTSD symptomatology after the COVID‐19 lockdown in cognitively unimpaired older adults

AbstractBackgroundCognitively unimpaired (CU) adults with Alzheimer’s disease (AD) pathologic change may be more vulnerable to developing neuropsychiatric symptoms. We reported an association of higher β‐amyloid (Aβ) and increased anxiety/depression during the COVID‐19 lockdown in CU adults (Akinci et al., 2022). Here, we investigated whether changes in Aβ1−42 predict post‐traumatic stress disorder (PTSD) symptomatology following COVID‐19 lockdown in CU adults at risk for AD.MethodWe included 128 CU participants who underwent lumbar puncture 2.3±0.6 years before and 1.1±0.4 years after the lockdown. The outcome of interest was self‐reported PTSD symptomatology (Impact of Event Scale Revised) measured 1.7±0.1 years after the lockdown. The main predictor was annual rate of change in cerebrospinal fluid (CSF) Aβ1−42 measured with the NeuroToolKit panel of robust prototype assays (Roche Diagnostics International Ltd, Rotkreuz, Switzerland). Other predictors included sex, age, years of education, stressors during COVID‐19, and anxiety/depression (Hospital Anxiety and Depression Scale, HADS) and perceived stress (Perceived Stress Scale, PSS) measured during lockdown. We performed regression analyses to explore the association between annual rate of change in Aβ1‐42 with PTSD scores adjusting for demographic and stressor variables, and further adjusting for HADS and PSS scores. We then explored the mediating effect of HADS and PSS on the association between change in Aβ1‐42 and PTSD scores.ResultParticipant age ranged from 53−72 and 59% were women (Table 1). Independent of demographic variables and stressors experienced during COVID‐19, the rate of annual change in Aβ1‐42 predicted PTSD scores (p = .008; Table 2). This association attenuated after introducing HADS and PSS scores into the model (p = .066). We found full mediation effects of HADS and PSS scores, explaining 46% and 40% of the effect of annual change in Aβ1‐42 on PTSD scores, respectively (Figure 1).ConclusionCU older adults with longitudinal CSF Aβ1−42 increases are more vulnerable to developing PTSD symptomatology after a stressful event, such as the pandemic. Anxiety/depression is one plausible mechanism through which increases in Aβ might exacerbate PTSD symptomatology. The results suggest a window for stress regulation during stressful events to prevent further mental health worsening in people at risk for AD.

Blood‐based biomarkers for Alzheimer’s Disease in Down Syndrome

AbstractBackgroundPeople with DS are at high risk to develop Alzheimer’s disease dementia (AD) (Lott &amp; Head, 2001). Predicting and monitoring decline and onset of dementia is a diagnostic challenge and of essence in daily care and support for people with DS. Behavioral and Psychological Symptoms of Dementia (BPSD) are an easily accessible tool for the prediction of dementia onset in the DS population. The BPSD‐DS II scale was developed and validated by our team to identify behavioral changes linked to AD between the last six months and pre‐existing behavior in an individual with DS (Dekker et al., 2021). This project is based on a cohort of DS individuals without AD (n = 94), with AD (n = 43), or with questionable AD (qAD) (n = 54) aged &gt;35 years. At inclusion, the BPSD‐DS II was applied to assess AD‐linked behavioral changes, and biofluid sampling was performed as well. Changes in cerebrospinal fluid (CSF) levels of monoaminergic neurotransmitters and metabolites have been associated with BPSD in AD (Dekker et al., 2015). However, CSF sampling procedures remain difficult in DS, illustrating the need for blood biomarkers. BPSD‐DS II results will be correlated with the serum levels of monoaminergic and classical AD biomarkers. Three years post‐inclusion, a follow‐up study was conducted to assess the evolution of possible AD dementia within this group and to determine the predictive values of the BPSD‐DS II scale and the different analytes.MethodWe will use reversed‐phase ultra‐high performance liquid chromatography with electrochemical detection to determine the levels of (nor)epinephrine, dopamine, serotonin and their metabolic products in serum. We will use the Simoaâ platform on the serum of clients with DS without or with (q)AD to detect the levels of Ab40, Ab42, total tau, phosphorylated tau, Glial Fibrillary Acidic Protein and Neurofilament Light chain.ResultWe expect a correlation between the results of the BPSD‐DS II and the levels of the monoamines and classical biomarkers in patients with DS without or with (q)AD.ConclusionThe diagnosis predicted by the results of the BPSD‐DS II correlates with the levels of monoamines and classical biomarkers in individuals with DS without or with (q)AD.

Sex‐dependent effects on the association between air pollution and longitudinal changes in CSF and plasma biomarkers of Alzheimer’s disease

AbstractBackgroundA growing body of research links environmental factors with neurodegeneration and premature mortality. However, the biological mechanisms through which the different pollutants may be affecting Alzheimer’s disease (AD) pathology in the early asymptomatic stages of AD and the downstream consequences are unknown. We aimed to evaluate the association between air pollution and longitudinal change rates of cerebrospinal fluid (CSF) and plasma biomarkers of AD in cognitively unimpaired individuals.MethodThe study included 195 middle‐aged cognitively unimpaired participants from the ALFA+ study, many within the Alzheimer’s continuum, with baseline and one follow‐up measurement of biomarkers of primary pathology of AD such as cerebrospinal fluid (CSF) β‐amyloid (Aβ) Aβ42/40 ratio (exploratory Roche NeuroToolKit assays [Roche Diagnostics International Ltd, Rotkreux, Switzerland]), plasma Aβ42/40 (Quanterix Simoa Neurology 4‐Plex E Advantage Kit), and CSF phosphorylated tau181 (p‐tau181) (Roche Elecsys® Phospho‐Tau [181P] CSF assay). Land use regression models were used to estimate individual levels of air pollution, including nitrogen oxide (NO2) and particulate matter (PM2.5, PM10), at the participants’ residential area. General linear models corrected by age, sex, APOE‐ε4 status, and time between measurements were conducted to assess the association between environmental exposures and biomarker changes. Sex‐specific effects were also investigated by including an interaction term.ResultHigher levels of exposure to PM2.5 were significantly associated with greater longitudinal reduction in plasma Aβ42/40 (β = ‐0.188, padjusted = 0.024). In addition, significant interactions between sex and NO2 (padj = 0.016), PM2.5 (padjusted = 0.008), and PM10 (padjusted = 0.007) on longitudinal change rates of plasma Aβ42/40 were found. Results showed that as the level of exposure increased, men presented reductions in plasma Aβ42/40 levels while women did not show significant changes (Figure 1). No significant results were found for longitudinal change rates of CSF biomarkers.ConclusionThese results reinforce the role of air pollution as a sex‐dependent environmental risk factor for AD pathology in asymptomatic individuals. Although more research is needed to elucidate the mechanisms involved in these associations, our results may inform better personalized prediction and prevention practices.

Brain metabolism during delirium

AbstractBackgroundAltered cerebral glucose metabolism manifested by increased cerebrospinal fluid (CSF) lactate and decreased neuron specific enolase during delirium has been found in CSF analyses in multiple settings, although without change in CSF or blood glucose. These changes correlate with markers of delirium severity and outcomes of delirium.However, patients with delirium are acutely unwell in hospital and have multiple comorbidities. The contribution of acute illness and dementia have not been excluded.MethodWe studied two groups of acutely unwell older people in hospital after excluding underlying dementia by history and the Informant Questionnaire on Cognitive Decline in the Elderly. The first group had delirium and the second group had no delirium. All patients underwent a 18F‐fluorodeoxyglucose positron emission tomography (FDG‐PET) scan in hospital while unwell, and during delirium for the first group. Confounders on FDG‐PET such as structural brain lesions and medications that affect brain metabolism were excluded.Then we also compared the delirium FDG‐PET scans to a group with Alzheimer’s dementia.ResultPatients with delirium demonstrated a unique, novel pattern of brain hypometabolism that reflected symptoms of delirium. The affected areas included: bilateral thalami; right posterior cingulate cortex (PCC); right superior frontal, right infero‐lateral anterior temporal and left superior parietal cortices. The areas highly negatively correlated with delirium severity scores (Spearman’s rank correlation coefficients between ρ = ‐0.39 and ‐0.71; p values from 0.089 to 0.001) and performance on a range of relevant neuropsychological tests, for example thalami and Trail Making Test B (Spearman’s ρ = ‐0.52; p = 0.028). Direct comparison to AD scans significant thalamic hypometabolism (p&lt;0.01) in delirium, but the PCC was not different.ConclusionIn patients with acute illness but without dementia, delirium is accompanied by regional cerebral hypometabolism in a distribution that is not consistent with any known pattern of dementia. While there is some overlap with AD, thalamic hypometabolism is atypical of AD and consistent with the clinical features of delirium.ReferencesNitchingham AR, Pereira JV‐B, Wegner EA, Oxenham V, Close J Caplan GA. Regional cerebral hypometabolism on 18F‐FDG PET/CT scan in delirium is independent of acute illness and dementia. Alzheimers &amp; Dementia 2022; 1‐10.

Associations of physical activity with cerebrospinal fluid biomarkers of neurodegeneration, neuroinflammation, and Alzheimer’s disease

AbstractBackgroundAlzheimer’s disease (AD) and related dementias are public health concerns often with long preclinical phases. Thus, intervention and prevention methods in midlife could prove efficacious. Cerebrospinal fluid (CSF) biomarkers can change early in the disease process and have been utilized for dementia diagnostics. Multiple health‐related lifestyle factors have been associated with risk for AD, yet existing research on lifestyle factors has focused on clinical outcomes such as cognitive decline, mild cognitive impairment and/or AD dementia; their associations with early changes in CSF are less understood. Our aim was to determine whether physical activity (PA), a modifiable lifestyle factor, is associated with biomarkers for neurodegeneration, glial activation, and inflammation.MethodParticipants were N = 204 cognitively unimpaired adults (aged 45–80 years) from the Wisconsin Registry for Alzheimer’s Prevention and the Wisconsin Alzheimer’s Disease Research Center, two on‐going, longitudinal studies of preclinical AD. PA was defined as the weekly metabolic equivalent (MET), calculated by scoring amount and intensity of mild, moderate, and vigorous exercises per week (range 0–79 METS). We assessed CSF biomarkers using robust exploratory prototype assays from the NeuroToolKit research platform (Roche Diagnostics International, Switzerland). Participants also completed demographic and health questionnaires (Table 1). We used linear regression models to assess associations between PA and CSF biomarkers, adjusting for age at biomarker assessment, sex, education, and chronic health conditions (diabetes, hypertension, cardiovascular disease).ResultPreliminary results showed that participants who engage in more PA had higher CSF S100B concentrations, a pro‐inflammatory calcium‐binding protein (standardized b change per MET = 0.0013, 95% confidence interval: 0.0003–0.0023; p = .01). No other PA‐biomarker associations were significant.ConclusionHigher PA was significantly associated with higher CSF concentration of S100B, a marker of (astro‐)glial activation. Future studies will need to examine whether PA is associated with higher S100B in individuals along the disease continuum of AD, and whether this is reflected in the blood. Longer follow‐ups may be needed to determine associations of PA with other biomarkers, where we had limited variation in this primarily healthy study cohort.

What do elevated cerebrospinal fluid p‐tau levels signify in the absence of beta‐amyloid pathology?

AbstractBackgroundThe introduction of the A/T/(N) (β‐amyloid/tau/neurodegeneration) framework has revealed an A‐T+ (β‐amyloid‐negative/tau‐positive) group which has been named suspected non‐Alzheimer’s pathophysiology. Cerebrospinal fluid (CSF) markers are often utilized to divide individuals in the A and T categories, but it is unclear what elevated CSF p‐tau levels signify in the absence of β‐amyloid. We aim to better understand A‐T+ as defined by CSF markers in two independent samples of cognitively unimpaired and impaired individuals by assessing baseline and longitudinal change in CSF, magnetic resonance (MRI), positron emission tomography (PET) and cognition measures.MethodCognitively normal (CN) and Mild Cognitive Impairment subjects from BioFINDER‐1 and 2 were included. A status was based on two CSF measures of β‐amyloid 42/40 (Aβ42/40) where A‐ individuals had to be negative on both measures using previously established cut offs. T status was determined by the 75th, 80th and 85th percentile of A‐ CN subjects for Roche Elecsys p‐tau181 (Table 1). Analyses of covariance and linear mixed models were performed to assess baseline and change differences in CSF (p‐tau181, Aβ42/40 ratio, neurofilament light (NFL)), MRI (hippocampal volume, entorhinal cortex and temporal meta‐region of interest thickness), cognition (modified Preclinical Alzheimer’s Cognitive Composite and delayed recall), and PET measures (entorhinal cortex Tau‐PET and early and global Alzheimer’s Disease composite β‐amyloid‐PET uptake) over 8 years (10 for cognition) for BioFINDER‐1 and 4 years for BioFINDER‐2.ResultIn A‐T+ versus A‐T‐, higher baseline NFL levels were found. No other baseline differences were found except for p‐tau181 and Aβ42/40 ratio by design. A‐T+ did not show significant change compared to A‐T‐ on any measure. Using different cut offs for p‐tau181 did not notably change the results. Comparisons with the A+ groups are shown in Figures 1‐2.ConclusionOur results indicate that A‐T+ as determined by p‐tau181 does not seem to be clinically meaningful as this group shows no decline on any of the biomarkers or cognitive measures over several years. The high NFL levels in the A‐T+ group suggest the presence of a latent factor that affects both NFL and p‐tau levels. Analyses will be repeated with other p‐tau isotopes and assays.

Safety of spinal anesthesia and analysis of cerebrospinal fluid in SARS-CoV-2 pregnant women undergoing cesarean section: an observational prospective study

BackgroundSystemic infection has always been considered a relative contraindication to neuraxial anesthesia, despite the fact that infectious complications are relatively uncommon. Pregnancy-related physiological changes and coronavirus disease (COVID-19) neurotropic features may facilitate the virus’ entry into the central nervous system. The principal aim of this study was to test the safety of spinal anesthesia in “severe acute respiratory syndrome coronavirus 2” (SARS-CoV-2)-positive pregnant women and to examine cerebrospinal fluid (CSF) characteristics.MethodsWe conducted a prospective observational single-center study in asymptomatic or paucisymptomatic consecutive pregnant SARS-CoV-2 patients who underwent spinal anesthesia for cesarean section. Women with severe infection were excluded because they underwent general anesthesia. At the time of spinal anesthesia, we collected CSF samples, and then we performed a chemical-physical analysis to look for signs of inflammation and for SARS-CoV-2 genome.ResultsWe included 26 women. No spinal anesthesia complications were reported in the perioperative period and after 2 months. All CSF samples were crystal clear, and all physical-chemical values were within physiological ranges: the median concentration of CSF/plasma glucose ratio was 0.66, IQR 0.5500 (0.6000–0.7100), and the average CSF protein concentration value was 23.2 mg/dl (SD 4.87). In all samples, genomes of SARS-CoV-2 and other neurotropic viruses were not detected.ConclusionsSpinal anesthesia was safe in SARS-CoV-2 pregnant women with mild disease; no clinical maternal complications were detected, and no CSF changes indicative of inflammatory or infectious diseases that would compromise the safety of the procedure were found.

Changes in Cerebrospinal Fluid, Liver and Intima-media-thickness Biomarkers in Patients with HIV-associated Neurocognitive Disorders Randomized to a Less Neurotoxic Treatment Regimen

The prevalence of neurocognitive impairment in people living with HIV is estimated between 30 and 50%. The pathogenesis of HIV-associated neurocognitive disorders is complex and multifactorial. Aim of the study was to measure the change in CSF biomarkers, Fibroscan and IMT measurements in PLWH with HAND randomized to a less neurotoxic regimen, or continuing their treatment. Adult patients with HAND were screened and enrolled if presenting no major resistance associated mutations, no HIV viral replication, not on efavirenz or darunavir, with R5-tropic HIV and without major confounding conditions. Lumbar puncture, IMT and Fibroscan measurements were performed. After 1:1 randomization to a less neurotoxic regimen consisting of darunavir/cobicistat plus emtricitabine plus maraviroc, or mantaining actual care, tests were repeated after 24 weeks: CSF biomarkes (HIV RNA, tau, p-tau, Beta-amyloid1-42, S100Beta and neopterin) were included. Non-parametric tests (Mann–Whitney and Wilcoxon’s) were used. 28 participants completed the study. Male and European ancestry were prevalent; median age was 55 years (51–60). All patients were virally suppressed; median CD4 + count was 626 cell/uL (469–772). Baseline characteristics were similar between the study arms. A significant decrease in CSF p-tau and an increase in CSF neopterin and NFL were observed. We observed a significant reduction in liver stiffness at W24. Despite a small sample size we observed changes in neuromarkers and in hepatic stiffness in patients randomized to the experimental arm. We observed changes in CSF biomarkers (lower phosphorylated-tau and higher neopterin and NFL) that need to be replicated in large cohorts. Subclinical neurotoxicity may be observed in patients with HAND and warrants prospective studies.Graphical

Evaluation of cerebrospinal fluid levels of synaptic vesicle protein, VAMP-2, across the sporadic Alzheimer’s disease continuum

BackgroundSynapse loss is an early event that precedes neuronal death and symptom onset and is considered the best neuropathological correlate of cognitive decline in Alzheimer’s disease (AD). Vesicle-associated membrane protein 2 (VAMP-2) has emerged as a promising biomarker of AD-related synapse degeneration in cerebrospinal fluid (CSF). The aim of this study was to explore the CSF profile of VAMP-2 across the AD continuum in relation to core AD biomarkers, other synaptic proteins, neurogranin (Ng) and synaptosomal-associated Protein-25 kDa (SNAP-25) and cognitive performance.MethodsWe developed a digital immunoassay on the Single Molecule Array platform to quantify VAMP-2 in CSF and used existing immunoassays to quantify Ng, SNAP-25 and core CSF AD biomarkers. The clinical study included 62 cognitively unimpaired AD biomarker-negative subjects and 152 participants across the AD continuum from the SPIN cohort (Sant Pau Initiative on Neurodegeneration). Cognitive measures of episodic, semantic, executive and visuospatial domains and global cognition were included. Statistical methods included χ2 tests, spearman correlation, and ANCOVA analyses.ResultsThe VAMP-2 assay had a good analytical performance (repeatability 8.9%, intermediate precision 10.3%). Assay antibodies detected native VAMP-2 protein in human brain homogenates. CSF concentrations of VAMP-2, neurogranin and SNAP-25 were lower in preclinical AD stage 1 compared to controls and higher at later AD stages compared to AD stage 1 and were associated with core AD biomarkers, particularly total tau (adj. r2 = 0.62 to 0.78, p < 0.001). All three synaptic proteins were associated with all cognitive domains in individuals on the AD continuum (adj. r2 = 0.04 to 0.19, p < 0.05).ConclusionsOur novel digital immunoassay accurately measures VAMP-2 changes in CSF, which reflect AD biomarkers and cognitive performance across multiple domains.

Clinical characteristics of tuberculous meningitis in older patients compared with younger and middle-aged patients: a retrospective analysis

BackgroundFew studies have analyzed the clinical characteristics and adverse factors affecting prognosis in older patients with tuberculous meningitis (TBM). This study aimed to compare the clinical characteristics of TBM in older patients with those in younger and middle-aged patients.MethodsThis single-center retrospective study extracted data on the clinical features, cerebrospinal fluid changes, laboratory results, imaging features, and outcomes of patients with TBM from patient medical records and compared the findings in older patients (aged 60 years and older) with those of younger and middle-aged patients (aged 18–59 years).ResultsThe study included 197 patients with TBM, comprising 21 older patients aged 60–76 years at onset, and 176 younger and middle-aged patients aged 18–59 years at onset. Fever was common in both older (81%) and younger and middle-aged patients (79%). Compared with younger and middle-aged patients, older patients were more likely to have changes in awareness levels (67% vs. 40%), peripheral nerve dysfunction (57% vs. 29%), changes in cognitive function (48% vs. 20%), and focal seizures (33% vs. 6%), and less likely to have headache (71% vs. 93%), neck stiffness on meningeal stimulation (38% vs. 62%), and vomiting (47% vs. 68%). The Medical Research Council staging on admission of older patients was stage II (52%) and stage III (38%), whereas most younger and middle-aged patients had stage I (33%) and stage II (55%) disease. Neurological function evaluated on the 28th day of hospitalization was more likely to show poor prognosis in older patients than in younger and middle-aged patients (76% vs. 25%). Older patients had significantly higher red blood cell counts and blood glucose levels, and significantly lower serum albumin and sodium levels than those in younger and middle-aged patients. The cerebrospinal fluid protein levels, nucleated cell counts, glucose levels, and chloride levels did not differ significantly by age.ConclusionIn patients with TBM, older patients have more severe clinical manifestations, a higher incidence of hydrocephalus and cerebral infarction, and longer hospital stays than younger and middle-aged patients. Older patients thus require special clinical attention.

Detecting macromolecular differences of the CSF in low disability multiple sclerosis using quantitative MT MRI at 3T.

Imaging investigation of cerebrospinal fluid (CSF) in multiple sclerosis (MS) is understudied. Development of noninvasive methods to detect pathological CSF changes would have a profound effect on MS diagnosis and would offer insight into MS pathophysiology and mechanisms of neurological impairment. We propose magnetization transfer (MT) MRI as a tool to detect macromolecular changes in spinal CSF. MT and quantitative MT (qMT) data were acquired in the cervical region in 27 people with relapsing-remitting multiple sclerosis (pwRRMS) and 38 age and sex-matched healthy controls (HCs). MT ratio (MTR), the B1, B0, and R1 corrected qMT-derived pool size ratio (PSR) were quantified in the spinal cord and CSF of each group. Both CSF MTR and CSF qMT-derived PSR were significantly increased in pwRRMS compared to HC (p = 0.027 and p = 0.020, respectively). CSF PSR of pwRRMS was correlated to Expanded Disability Status Scale Scores (p = 0.045, R = 0.352). Our findings demonstrate increased CSF macromolecular content in pwRRMS and link CSF macromolecular content with clinical impairment. This highlights the potential role of CSF in processing products of demyelination.

A microglial activity state biomarker panel differentiates FTD-granulin and Alzheimer’s disease patients from controls

BackgroundWith the emergence of microglia-modulating therapies there is an urgent need for reliable biomarkers to evaluate microglial activation states.MethodsUsing mouse models and human induced pluripotent stem cell-derived microglia (hiMGL), genetically modified to yield the most opposite homeostatic (TREM2-knockout) and disease-associated (GRN-knockout) states, we identified microglia activity-dependent markers. Non-targeted mass spectrometry was used to identify proteomic changes in microglia and cerebrospinal fluid (CSF) of Grn- and Trem2-knockout mice. Additionally, we analyzed the proteome of GRN- and TREM2-knockout hiMGL and their conditioned media. Candidate marker proteins were tested in two independent patient cohorts, the ALLFTD cohort (GRN mutation carriers versus non-carriers), as well as the proteomic data set available from the EMIF-AD MBD study.ResultsWe identified proteomic changes between the opposite activation states in mouse microglia and CSF, as well as in hiMGL cell lysates and conditioned media. For further verification, we analyzed the CSF proteome of heterozygous GRN mutation carriers suffering from frontotemporal dementia (FTD). We identified a panel of six proteins (FABP3, MDH1, GDI1, CAPG, CD44, GPNMB) as potential indicators for microglial activation. Moreover, we confirmed three of these proteins (FABP3, GDI1, MDH1) to be significantly elevated in the CSF of Alzheimer’s (AD) patients. Remarkably, each of these markers differentiated amyloid-positive cases with mild cognitive impairment (MCI) from amyloid-negative individuals.ConclusionsThe identified candidate proteins reflect microglia activity and may be relevant for monitoring the microglial response in clinical practice and clinical trials modulating microglial activity and amyloid deposition. Moreover, the finding that three of these markers differentiate amyloid-positive from amyloid-negative MCI cases in the AD cohort suggests that these proteins associate with a very early immune response to seeded amyloid. This is consistent with our previous findings in the Dominantly Inherited Alzheimer’s Disease Network (DIAN) cohort, where soluble TREM2 increases as early as 21 years before symptom onset. Moreover, in mouse models for amyloidogenesis, seeding of amyloid is limited by physiologically active microglia further supporting their early protective role. The biological functions of some of our main candidates (FABP3, CD44, GPNMB) also further emphasize that lipid dysmetabolism may be a common feature of neurodegenerative disorders.

Evolution of neurodegeneration in patients with normal pressure hydrocephalus: a monocentric follow up study

BackgroundThe aim of this study was to examine in patients with idiopathic and neurodegenerative normal pressure hydrocephalus (NPH) if motor and cognitive performance as well as changes in biomarkers in cerebrospinal fluid (CSF) evolve differently.Methods41 patients with a typical clinical and MR-/CT-morphological presentation of NPH divided into an Alzheimer-negative (AD–, n = 25) and an Alzheimer-positive (AD+, n = 16) group according to neurodegenerative biomarkers (S100 protein, neuron-specific enolase, β-amyloid 1–42, Tau protein, phospho-Tau, protein-level and CSF pressure) in CSF. Follow-up of cognitive and gait functions before and after a spinal tap of 40–50 ml CSF of up to 49 months. Clinical, motor, neuropsychological and CSF biomarkers were analyzed using a repeated multifactorial analysis of variance (ANOVA) with post-hoc testing.ResultsGait and neuropsychological performance and CSF biomarkers evolved differently between the AD− and AD+ patients. In particular, the AD+ patients benefited from the spinal tap regarding short-term memory. In contrast, gait parameters worsened over time in the AD+ patients, although they showed a relevant improvement after the first tap.ConclusionsThe results substantiate the recently reported association between a tap-responsive NPH and CSF changes of Alzheimer disease. Furthermore, they suggest that the AD changes in CSF manifest in an age-related fashion in AD− patients presenting with NPH.

Neurodegeneration or dysfunction in Phelan-McDermid syndrome? A multimodal approach with CSF and computational MRI

BackgroundPhelan-McDermid syndrome (PMS) is a rare multisystem disease with global developmental delay and autistic features. Genetically, the disease is based on a heterozygous deletion of chromosome 22q13.3 with involvement of at least part of the SHANK3 gene or heterozygous pathogenic variants in SHANK3. Pathophysiologically, this syndrome has been regarded as a synaptopathy, but current data suggest an additional concept, since axonal functions of neurons are also impaired, thus, the specific pathophysiological processes in this disease are not yet fully understood. Since symptoms of the autism spectrum, regression, and stagnation in development occur, we investigated whether neuroinflammatory and neurodegenerative processes may also play a role. To this end, we analysed biomarkers in cerebrospinal fluid (CSF) and parameters from magnetic resonance imaging with high-resolution structural T1w volumetry and diffusion tensor imaging analysis in 19 Phelan-McDermid syndrome patients.ResultsCSF showed no inflammation but abnormalities in tau protein and amyloid-ß concentrations, however, with no typical biomarker pattern as in Alzheimer’s disease. It could be demonstrated that these CSF changes were correlated with integrity losses of the fibres in the corticospinal tract as well as in the splenium and dorsal part of the cingulum. High CSF levels of tau protein were associated with loss of integrity of fibres in the corticospinal tract; lower levels of amyloid-ß were associated with decreasing integrity of fibre tracts of the splenium and posterior cingulate gyrus. Volumetric investigations showed global atrophy of the white matter, but not the grey matter, and particularly not in temporal or mesiotemporal regions, as is typical in later stages of Alzheimer’s disease.ConclusionsIn summary, alterations of neurodegenerative CSF markers in PMS individuals could be demonstrated which were correlated with structural connectivity losses of the corticospinal tract, the splenium, and the dorsal part of the cingulum, which can also be associated with typical clinical symptoms in these patients. These findings might represent a state of dysfunctional processes with ongoing degenerative and regenerative processes or a kind of accelerated aging. This study should foster further clinical diagnostics like tau- and amyloid-PET imaging as well as novel scientific approaches especially in basic research for further mechanistic proof.

The Association of Selected GWAS Reported AD Risk Loci with CSF Biomarker Levels and Cognitive Decline in Slovenian Patients.

Alzheimer's disease (AD) is the most common neurodegenerative disease, with a complex genetic background. Apart from rare, familial cases, a combination of multiple risk loci contributes to the susceptibility of the disease. Genome-wide association studies (GWAS) have identified numerous AD risk loci. Changes in cerebrospinal fluid (CSF) biomarkers and imaging techniques can detect AD-related brain changes before the onset of clinical symptoms, even in the presence of preclinical mild cognitive impairment. In this study, we aimed to assess the associations between SNPs in well-established GWAS AD risk loci and CSF biomarker levels or cognitive test results in Slovenian patients with cognitive decline. The study included 82 AD patients, 28 MCI patients with pathological CSF biomarker levels and 35 MCI patients with normal CSF biomarker levels. Carriers of at least one polymorphic TOMM40 rs157581 C allele had lower Aβ42 (p = 0.033) and higher total tau (p = 0.032) and p-tau181 levels (p = 0.034). Carriers of at least one polymorphic T allele in SORCS1 rs1358030 had lower total tau (p = 0.019), while polymorphic SORCS1 rs1416406 allele was associated with lower total tau (p = 0.013) and p-tau181 (p = 0.036). In addition, carriers of at least one polymorphic T allele in BCHE rs1803274 had lower cognitive test scores (p = 0.029). The study findings may contribute to the identification of genetic markers associated with AD and MCI and provide insights into early disease diagnostics.

Diagnostic challenge of tuberculosis in systemic lupus erythematosus: a case report and literature review.

Patients with systemic lupus erythematosus (SLE) are at increased risk of tuberculosis (TB) infection due to immune dysfunction and immunosuppressive therapy. We present a case study of a 40-year-old woman with systemic lupus erythematosus (SLE). Initially, she was diagnosed with a lupus flare based on her clinical symptoms and laboratory results. However, upon further investigation, positive polymerase-chain reaction results for M. tuberculosis in the cerebrospinal fluid and lung parenchymal changes on chest computed tomography scan were indicative of TB infection. There was initial uncertainty regarding whether TB had triggered a flare-up of SLE or if TB was merely mimicking the symptoms of a SLE flare-up. However, as increasing the prednisolone dose did not have a positive effect and the patient's condition improved significantly with anti-TB treatment alone, it became clearer that the deterioration observed upon admission was primarily due to TB progression rather than an SLE flare-up. Additionally, we review the current literature on TB and SLE, including risk factors, diagnostic challenges, and treatment considerations, highlighting the importance of considering TB infection in patients with SLE who present with overlapping manifestations. Prompt diagnosis and treatment are essential for improving outcomes in these patients.