A consensus protocol for the standardization of cerebrospinal fluid collection and biobanking

Vitamin D-An Effective Antioxidant in an Animal Model of Progressive Multiple Sclerosis

Vitamin D (VD) is the most discussed antioxidant supplement for multiple sclerosis (MS) patients and many studies suggest correlations between a low VD serum level and onset and progression of the disease. While many studies in animals as well as clinical studies focused on the role of VD in the relapsing-remitting MS, knowledge is rather sparse for the progressive phase of the disease and the development of cortical pathology. In this study, we used our established rat model of cortical inflammatory demyelination, resembling features seen in late progressive MS, to address the question about whether VD could have positive effects on reducing cortical pathology, oxidative stress, and neurofilament light chain (NfL) serum levels. For this purpose, we used male Dark Agouti (DA) rats, with one group being supplemented with VD (400 IE per week; VD+) from the weaning on at age three weeks; the other group received standard rodent food. The rat brains were assessed using immunohistochemical markers against demyelination, microglial activation, apoptosis, neurons, neurofilament, and reactive astrocytes. To evaluate the effect of VD on oxidative stress and the antioxidant capacity, we used two different oxidized lipid markers (anti- Cu++ and HOCl oxidized LDL antibodies) along with colorimetric methods for protective polyphenols (PP) and total antioxidative capacity (TAC). NfL serum levels of VD+ and VD- animals were analyzed by fourth generation single-molecule array (SIMOA) analysis. We found significant differences between the VD+ and VD- animals both in histopathology as well as in all serum markers. Myelin loss and microglial activation is lower in VD+ animals and the number of apoptotic cells is significantly reduced with a higher neuronal survival. VD+ animals show significantly lower NfL serum levels, a higher TAC, and more PP. Additionally, there is a significant reduction of oxidized lipid markers in animals under VD supplementation. Our data thus show a positive effect of VD on cellular features of cortical pathology in our animal model, presumably due to protection against reactive oxygen species. In this study, VD enhanced remyelination and prevented neuroaxonal and oxidative damage, such as demyelination and neurodegeneration. However, more studies on VD dose relations are required to establish an optimal response while avoiding overdosing.

CSF Synaptic Biomarkers in AT(N)-Based Subgroups of Lewy Body Disease

BACKGROUND AND OBJECTIVES

Patients with Lewy body disease (LBD) often show a co-occurring Alzheimer disease (AD) pathology. CSF biomarkers allow the detection in vivo of AD-related pathologic hallmarks included in the amyloid-tau-neurodegeneration (AT(N)) classification system. Here, we aimed to investigate whether CSF biomarkers of synaptic and neuroaxonal damage are correlated with the presence of AD copathology in LBD and can be useful to differentiate patients with LBD with different AT(N) profiles.

METHODS

We retrospectively measured CSF levels of AD core biomarkers (Aβ42/40 ratio, phosphorylated tau protein, and total tau protein) and of synaptic (β-synuclein, α-synuclein, synaptosomal-associated protein 25 [SNAP-25], and neurogranin) and neuroaxonal proteins (neurofilament light chain [NfL]) in 28 cognitively unimpaired participants with nondegenerative neurologic conditions and 161 participants with a diagnosis of either LBD or AD (at both mild cognitive impairment, AD-MCI, and dementia stages, AD-dem). We compared CSF biomarker levels in clinical and AT(N)-based subgroups.

RESULTS

CSF β-synuclein, α-synuclein, SNAP-25, neurogranin, and NfL levels did not differ between LBD (n = 101, age 67.2 ± 7.8 years, 27.7% females) and controls (age 64.8 ± 8.6 years, 39.3% females) and were increased in AD (AD-MCI: n = 30, AD-dem: n = 30, age 72.3 ± 6.0 years, 63.3% females) compared with both groups (p < 0.001 for all comparisons). In LBD, we found increased levels of synaptic and neuroaxonal degeneration biomarkers in patients with A+T+ (LBD/A+T+) than with A-T- profiles (LBD/A-T-) (p < 0.01 for all), and β-synuclein showed the highest discriminative accuracy between the 2 groups (area under the curve 0.938, 95% CI 0.884-0.991). CSF β-synuclein (p = 0.0021), α-synuclein (p = 0.0099), and SNAP-25 concentrations (p = 0.013) were also higher in LBD/A+T+ than in LBD/A+T- cases, which had synaptic biomarker levels within the normal range. CSF α-synuclein was significantly decreased only in patients with LBD with T- profiles compared with controls (p = 0.0448). Moreover, LBD/A+T+ and AD cases did not differ in any biomarker level.

DISCUSSION

LBD/A+T+ and AD cases showed significantly increased CSF levels of synaptic and neuroaxonal biomarkers compared with LBD/A-T- and control subjects. Patients with LBD and AT(N)-based AD copathology showed, thus, a distinct signature of synaptic dysfunction from other LBD cases.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that CSF levels of β-synuclein, α-synuclein, SNAP-25, neurogranin, and NfL are higher in patients with AD than in patients with LBD.

Thimet oligopeptidase as a potential CSF biomarker for Alzheimer's disease: A cross-platform validation study

INTRODUCTION

Our previous antibody-based cerebrospinal fluid (CSF) proteomics study showed that Thimet oligopeptidase (THOP1), an amyloid beta (Aβ) neuropeptidase, was increased in mild cognitive impairment with amyloid pathology (MCI-Aβ+) and Alzheimer's disease (AD) dementia compared with controls and dementia with Lewy bodies (DLB), highlighting the potential of CSF THOP1 as an early specific biomarker for AD. We aimed to develop THOP1 immunoassays for large-scale analysis and validate our proteomics findings in two independent cohorts.

METHODS

We developed in-house CSF THOP1 immunoassays on automated Ella and Simoa platforms. The performance of the different assays were compared using Passing-Bablok regression analysis in a subset of CSF samples from the discovery cohort (n = 72). Clinical validation was performed in two independent cohorts (cohort 1: n = 200; cohort 2: n = 165) using the Ella platform.

RESULTS

THOP1 concentrations moderately correlated between proteomics analysis and our novel assays (Rho > 0.580). In both validation cohorts, CSF THOP1 was increased in MCI-Aβ+ (>1.3-fold) and AD (>1.2-fold) compared with controls; and between MCI-Aβ+ and DLB (>1.2-fold). Higher THOP1 concentrations were detected in AD compared with DLB only when both cohorts were analyzed together. In both cohorts, THOP1 correlated with CSF total tau (t-tau), phosphorylated tau (p-tau), and Aβ40 (Rho > 0.540) but not Aβ42.

DISCUSSION

Validation of our proteomics findings underpins the potential of CSF THOP1 as an early specific biomarker associated with AD pathology. The use of antibody-based platforms in both the discovery and validation phases facilitated the translation of proteomics findings, providing an additional workflow that may accelerate the development of biofluid-based biomarkers.

Charting the Next Road Map for CSF Biomarkers in Alzheimer's Disease and Related Dementias

Clinical prediction of underlying pathologic substrates in people with Alzheimer's disease (AD) dementia or related dementia syndromes (ADRD) has limited accuracy. Etiologic biomarkers - including cerebrospinal fluid (CSF) levels of AD proteins and cerebral amyloid PET imaging - have greatly modernized disease-modifying clinical trials in AD, but their integration into medical practice has been slow. Beyond core CSF AD biomarkers (including beta-amyloid 1-42, total tau, and tau phosphorylated at threonine 181), novel biomarkers have been interrogated in single- and multi-centered studies with uneven rigor. Here, we review early expectations for ideal AD/ADRD biomarkers, assess these goals' future applicability, and propose study designs and performance thresholds for meeting these ideals with a focus on CSF biomarkers. We further propose three new characteristics: equity (oversampling of diverse populations in the design and testing of biomarkers), access (reasonable availability to 80% of people at risk for disease, along with pre- and post-biomarker processes), and reliability (thorough evaluation of pre-analytical and analytical factors influencing measurements and performance). Finally, we urge biomarker scientists to balance the desire and evidence for a biomarker to reflect its namesake function, indulge data- as well as theory-driven associations, re-visit the subset of rigorously measured CSF biomarkers in large datasets (such as Alzheimer's disease neuroimaging initiative), and resist the temptation to favor ease over fail-safe in the development phase. This shift from discovery to application, and from suspended disbelief to cogent ingenuity, should allow the AD/ADRD biomarker field to live up to its billing during the next phase of neurodegenerative disease research.

Homeostasis of serine enantiomers is disrupted in the post-mortem caudate putamen and cerebrospinal fluid of living Parkinson's disease patients

L-serine generated in astrocytes plays a pivotal role in modulating essential neurometabolic processes, while its enantiomer, D-serine, specifically regulates NMDA receptor (NMDAR) signalling. Despite their physiological relevance in modulating cerebral activity, serine enantiomers metabolism in Parkinson's disease (PD) remains elusive. Using High-Performance Liquid Chromatography (HPLC), we measured D- and L-serine levels along with other amino acids known to modulate NMDAR function, such as L-glutamate, L-aspartate, D-aspartate, and glycine, in the post-mortem caudate putamen (CPu) and superior frontal gyrus (SFG) of PD patients. Moreover, we examined these amino acids in the cerebrospinal fluid (CSF) of de novo living PD, Alzheimer's disease (AD), and amyotrophic lateral sclerosis (ALS) patients versus subjects with other neurological disorders (OND), used as control. We found higher D-serine and L-serine levels in the CPu of PD patients but not in the SFG, a cerebral region that, in contrast to the CPu, is not innervated by nigral dopaminergic terminals. We also highlighted a significant elevation of both serine enantiomers in the CSF samples from PD but not in those of AD and ALS patients, compared with control subjects. By contrast, none or only minor changes were found in the amount of other neuroactive amino acids mentioned above. Our findings identify D-serine and L-serine level upregulation as a biochemical signature associated with nigrostriatal dopaminergic degeneration in PD.

Disease phenotype prediction in multiple sclerosis

Progressive multiple sclerosis (PMS) is currently diagnosed retrospectively. Here, we work toward a set of biomarkers that could assist in early diagnosis of PMS. A selection of cerebrospinal fluid metabolites (n = 15) was shown to differentiate between PMS and its preceding phenotype in an independent cohort (AUC = 0.93). Complementing the classifier with conformal prediction showed that highly confident predictions could be made, and that three out of eight patients developing PMS within three years of sample collection were predicted as PMS at that time point. Finally, this methodology was applied to PMS patients as part of a clinical trial for intrathecal treatment with rituximab. The methodology showed that 68% of the patients decreased their similarity to the PMS phenotype one year after treatment. In conclusion, the inclusion of confidence predictors contributes with more information compared to traditional machine learning, and this information is relevant for disease monitoring.

Immune profiling in multiple sclerosis: a single-center study of 65 cytokines, chemokines, and related molecules in cerebrospinal fluid and serum

Introduction

The understanding of the pathophysiology of multiple sclerosis (MS) has evolved alongside the characterization of cytokines and chemokines in cerebrospinal fluid (CSF) and serum. However, the complex interplay of pro- and anti-inflammatory cytokines and chemokines in different body fluids in people with MS (pwMS) and their association with disease progression is still not well understood and needs further investigation. Therefore, the aim of this study was to profile a total of 65 cytokines, chemokines, and related molecules in paired serum and CSF samples of pwMS at disease onset.

Methods

Multiplex bead-based assays were performed and baseline routine laboratory diagnostics, magnetic resonance imaging (MRI), and clinical characteristics were assessed. Of 44 participants included, 40 had a relapsing-remitting disease course and four a primary progressive MS.

Results

There were 29 cytokines and chemokines that were significantly higher in CSF and 15 in serum. Statistically significant associations with moderate effect sizes were found for 34 of 65 analytes with sex, age, CSF, and MRI parameters and disease progression.

Discussion

In conclusion, this study provides data on the distribution of 65 different cytokines, chemokines, and related molecules in CSF and serum in newly diagnosed pwMS.

Differential associations of clinical features with cerebrospinal fluid biomarkers in dementia with Lewy bodies and Alzheimer's disease

AIM

To explore associations of cerebrospinal fluid biomarkers of neurodegeneration and amyloidosis with caregiver burden, cognition and functionality in dementia with Lewy bodies (DLB) paired with late-onset Alzheimer's disease (AD) and healthy older people.

METHODS

Consecutive outpatients with DLB were matched with outpatients with AD according to sex, cognitive scores and dementia stage, and with cognitively healthy controls according to age and sex to investigate associations of cerebrospinal fluid amyloid-β (Aβ₄₂,Aβ₄₀,Aβ₃₈), tau, phospho-tau Thr₁₈₁, ubiquitin, α-synuclein and neurofilament light with caregiver burden, functionality, reverse digit span, a clock drawing test, Mini-Mental State Examination (MMSE) and Severe MMSE, adjusted for sex, age, education, dementia duration and APOE-ε4 alleles.

RESULTS

Overall, 27 patients with DLB (78.98 ± 9.0 years-old; eleven APOE-ε4 +) were paired with 27 patients with AD (81.50 ± 5.8 years-old; twelve APOE-ε4 +) and 27 controls (78.98 ± 8.7 years-old; four APOE-ε4 +); two-thirds were women. In AD, Aβ₄₂/Aβ₃₈ and Aβ₄₂ were lower, while tau/Aβ₄₂ and phospho-tau Thr₁₈₁/Aβ₄₂ were higher; α-synuclein/Aβ₄₂ was lower in DLB and higher in AD. The following corrected associations remained significant: in DLB, instrumental functionality was inversely associated with tau/phospho-tau Thr₁₈₁ and tau/Aβ₄₂, and reverse digit span associated with α-synuclein; in AD, instrumental functionality was inversely associated with neurofilament light, clock drawing test scores inversely associated with phospho-tau Thr₁₈₁/Aβ₄₂ and α-synuclein/Aβ₄₂, and Severe MMSE inversely associated with tau/Aβ₄₂ and tau/phospho-tau Thr₁₈₁.

CONCLUSIONS

Cerebrospinal fluid phospho-tau Thr₁₈₁ in DLB was similar to AD, but not Aβ₄₂. In associations with test scores, biomarker ratios were superior to isolated biomarkers, while worse functionality was associated with axonal degeneration only in AD.

Review and standard operating procedures for collection of biospecimens and analysis of biomarkers in new onset refractory status epilepticus

New onset refractory status epilepticus (NORSE), including its subtype with a preceding febrile illness known as febrile infection-related epilepsy syndrome (FIRES), is one of the most severe forms of status epilepticus. The exact causes of NORSE are currently unknown, and there is so far no disease-specific therapy. Identifying the underlying pathophysiology and discovering specific biomarkers, whether immunologic, infectious, genetic, or other, may help physicians in the management of patients with NORSE. A broad spectrum of biomarkers has been proposed for status epilepticus patients, some of which were evaluated for patients with NORSE. Nonetheless, none has been validated, due to significant variabilities in study cohorts, collected biospecimens, applied analytical methods, and defined outcome endpoints, and to small sample sizes. The NORSE Institute established an open NORSE/FIRES biorepository for health-related data and biological samples allowing the collection of biospecimens worldwide, promoting multicenter research and sharing of data and specimens. Here, we suggest standard operating procedures for biospecimen collection and biobanking in this rare condition. We also propose criteria for the appropriate use of previously collected biospecimens. We predict that the widespread use of standardized procedures will reduce heterogeneity, facilitate the future identification of validated biomarkers for NORSE, and provide a better understanding of the pathophysiology and best clinical management for these patients.

Remodeling of the neuromuscular junction in myasthenia gravis increases serum neurofilament heavy chain levels

INTRODUCTION/AIMS

In myasthenia gravis, prolonged muscle denervation causes muscle atrophy. We re-visited this observation using a biomarker hypothesis. We tested if serum neurofilament heavy chain levels, a biomarker for axonal degeneration, were elevated in myasthenia gravis.

METHODS

We enrolled 70 patients with isolated ocular myasthenia gravis and 74 controls recruited from patients in the emergency department. Demographic data were collected alongside serum samples. Serum samples were analyzed by enzyme-linked immunosorbent assay (ELISA) for the neurofilament heavy chain (NfH-SMI35). The statistical analyses included group comparisons, receiver operator characteristic (ROC) curves, area under the curve (AUC), sensitivity, specificity, and positive and negative predictive values.

RESULTS

Serum neurofilament heavy chain levels were significantly (p < 0.0001) higher in individuals with myasthenia gravis (0.19 ng/mL) than in healthy control subjects (0.07 ng/mL). A ROC AUC optimized cutoff level of 0.06 ng/mL gave a diagnostic sensitivity of 82%, specificity of 76%, positive predictive value of 0.77 and a negative predictive value of 0.81.

DISCUSSION

The increase of serum neurofilament heavy chain levels in myasthenia gravis is consistent with observations of muscle denervation. We suggest that there is ongoing remodeling of the neuromuscular junction in myasthenia gravis. Longitudinal quantification of neurofilament isoform levels will be needed to investigate the prognostic value and potentially guide treatment decisions.

Neuroinflammatory CSF biomarkers MIF, sTREM1, and sTREM2 show dynamic expression profiles in Alzheimer's disease

BACKGROUND

There is a need for novel fluid biomarkers tracking neuroinflammatory responses in Alzheimer's disease (AD). Our recent cerebrospinal fluid (CSF) proteomics study revealed that migration inhibitory factor (MIF) and soluble triggering receptor expressed on myeloid cells 1 (sTREM1) increased along the AD continuum. We aimed to assess the potential use of these proteins, in addition to sTREM2, as CSF biomarkers to monitor inflammatory processes in AD.

METHODS

We included cognitively unimpaired controls (n = 67, 63 ± 9 years, 24% females, all amyloid negative), patients with mild cognitive impairment (MCI; n = 92, 65 ± 7 years, 47% females, 65% amyloid positive), AD (n = 38, 67 ± 6 years, 8% females, all amyloid positive), and DLB (n = 50, 67 ± 6 years, 5% females, 54% amyloid positive). MIF, sTREM1, and sTREM2 levels were measured by validated immunoassays. Differences in protein levels between groups were tested with analysis of covariance (corrected for age and sex). Spearman correlation analysis was performed to evaluate the association between these neuroinflammatory markers with AD-CSF biomarkers (Aβ42, tTau, pTau) and mini-mental state examination (MMSE) scores.

RESULTS

MIF levels were increased in MCI (p < 0.01), AD (p < 0.05), and DLB (p > 0.05) compared to controls. Levels of sTREM1 were specifically increased in AD compared to controls (p < 0.01), MCI (p < 0.05), and DLB patients (p > 0.05), while sTREM2 levels were increased specifically in MCI compared to all other groups (all p < 0.001). Neuroinflammatory proteins were highly correlated with CSF pTau levels (MIF: all groups; sTREM1: MCI, AD and DLB; sTREM2: controls, MCI and DLB). Correlations with MMSE scores were observed in specific clinical groups (MIF in controls, sTREM1 in AD, and sTREM2 in DLB).

CONCLUSION

Inflammatory-related proteins show diverse expression profiles along different AD stages, with increased protein levels in the MCI stage (MIF and sTREM2) and AD stage (MIF and sTREM1). The associations of these inflammatory markers primarily with CSF pTau levels indicate an intertwined relationship between tau pathology and inflammation. These neuroinflammatory markers might be useful in clinical trials to capture dynamics in inflammatory responses or monitor drug-target engagement of inflammatory modulators.

Misfolded α-Synuclein Assessment in the Skin and CSF by RT-QuIC in Isolated REM Sleep Behavior Disorder

BACKGROUND AND OBJECTIVES

Real-time quaking-induced conversion (RT-QuIC) assay detects misfolded α-synuclein (AS) in the skin and CSF of patients with the synucleinopathies Parkinson disease and dementia with Lewy bodies. Isolated REM sleep behavior disorder (IRBD) constitutes the prodromal stage of these synucleinopathies. We aimed to compare the ability of RT-QuIC to identify AS in the skin and CSF of patients with IRBD.

METHODS

This was a cross-sectional study where consecutive patients with polysomnographic-confirmed IRBD and age-matched controls without RBD underwent skin biopsy and lumbar puncture the same day. Three-millimeter skin punch biopsies were obtained bilaterally in the cervical region from dorsal C7 and C8 dermatomes and in distal legs. RT-QuIC assessed AS in these 6 skin sites and the CSF.

RESULTS

We recruited 91 patients with IRBD and 41 controls. In the skin, sensitivity to detect AS was 76.9% (95% CI 66.9-85.1), specificity 97.6% (95% CI 87.1-99.9) positive predictive value 98.6% (95% CI 91.0-99.8), negative predictive value 65.6% (95% CI 56.6-73.6), and accuracy 83.3% (95% CI 75.9-89.3). In the CSF, the sensitivity was 75.0% (95% CI 64.6-83.6), the specificity was 97.5% (95% CI 86.8-99.9), the positive predictive value was 98.5% (95% CI 90.5-99.8), the negative predictive value was 63.9% (95% CI 55.2-71.9), and the accuracy was 82.0% (95% CI 74.3-88.3). Results in the skin and CSF samples showed 99.2% agreement. Compared with negative patients, RT-QuIC AS-positive patients had a higher likelihood ratio of prodromal Parkinson disease (p < 0.001) and showed more frequently hyposmia (p < 0.001), dopamine transporter imaging single-photon emission CT deficit (p = 0.002), and orthostatic hypotension (p = 0.014). No severe or moderate adverse effects were reported. There was no difference between the percentage of participants reporting mild adverse events secondary to skin biopsy or lumbar puncture (9.1% vs 17.2%; p = 0.053). One hundred and ten (83%) and 104 (80%) participants, respectively, stated they would accept to undergo skin biopsy and lumbar puncture again for research purposes.

DISCUSSION

Our study in IRBD shows that (1) RT-QuIC detects AS in the skin and CSF with similar high sensitivity, specificity, and agreement, (2) AS RT-QuIC positivity is associated with supportive features and biomarkers of synucleinopathy, and (3) skin punch biopsy and lumbar puncture have comparable mild adverse effects, tolerance, and acceptance. RT-QuIC in the skin or CSF might represent a patient selection strategy for future neuroprotective trials targeting AS in IRBD.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that RT-QuIC-detected AS in the skin and CSF distinguishes patients with IRBD from controls.

A multimodal marker for cognitive functioning in multiple sclerosis: the role of NfL, GFAP and conventional MRI in predicting cognitive functioning in a prospective clinical cohort

BACKGROUND

Cognitive impairment in people with MS (PwMS) has primarily been investigated using conventional imaging markers or fluid biomarkers of neurodegeneration separately. However, the single use of these markers do only partially explain the large heterogeneity found in PwMS.

OBJECTIVE

To investigate the use of multimodal (bio)markers: i.e., serum and cerebrospinal fluid (CSF) levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) and conventional imaging markers in predicting cognitive functioning in PwMS.

METHODS

Eighty-two PwMS (56 females, disease duration = 14 ± 9 years) underwent neuropsychological and neurological examination, structural magnetic resonance imaging, blood sampling and lumbar puncture. PwMS were classified as cognitively impaired (CI) if scoring ≥ 1.5SD below normative scores on ≥ 20% of test scores. Otherwise, PwMS were defined as cognitively preserved (CP). Association between fluid and imaging (bio)markers were investigated, as well as binary logistics regression to predict cognitive status. Finally, a multimodal marker was calculated using statistically important predictors of cognitive status.

RESULTS

Only higher NfL levels (in serum and CSF) correlated with worse processing speed (r = - 0.286, p = 0.012 and r = - 0.364, p = 0.007, respectively). sNfL added unique variance in the prediction of cognitive status on top of grey matter volume (NGMV), p = 0.002). A multimodal marker of NGMV and sNfL yielded most promising results in predicting cognitive status (sensitivity = 85%, specificity = 58%).

CONCLUSION

Fluid and imaging (bio)markers reflect different aspects of neurodegeneration and cannot be used interchangeably as markers for cognitive functioning in PwMS. The use of a multimodal marker, i.e., the combination of grey matter volume and sNfL, seems most promising for detecting cognitive deficits in MS.

CSF neurochemical profile and cognitive changes in Parkinson's disease with mild cognitive impairment

Pathophysiological substrate(s) and progression of Parkinson's disease (PD) with mild cognitive impairment (PD-MCI) are still matter of debate. Baseline cerebrospinal fluid (CSF) neurochemical profile and cognitive changes after 2 years were investigated in a retrospective series of PD-MCI (n = 48), cognitively normal PD (PD-CN, n = 40), prodromal Alzheimer's disease (MCI-AD, n = 25) and cognitively healthy individuals with other neurological diseases (OND, n = 44). CSF biomarkers reflecting amyloidosis (Aβ42/40 ratio, sAPPα, sAPPβ), tauopathy (p-tau), neurodegeneration (t-tau, NfL, p-NfH), synaptic damage (α-syn, neurogranin) and glial activation (sTREM2, YKL-40) were measured. The great majority (88%) of PD-MCI patients was A-/T-/N-. Among all biomarkers considered, only NfL/p-NfH ratio was significantly higher in PD-MCI vs. PD-CN (p = 0.02). After 2 years, one-third of PD-MCI patients worsened; such worsening was associated with higher baseline levels of NfL, p-tau, and sTREM2. PD-MCI is a heterogeneous entity requiring further investigations on larger, longitudinal cohorts with neuropathological verification.

Serum but not cerebrospinal fluid levels of allantoin are increased in de novo Parkinson's disease

Oxidative stress supposedly plays a role in the pathogenesis of Parkinson's disease (PD). Uric acid (UA), a powerful antioxidant, is lowered in PD while allantoin, the oxidation product of UA and known biomarker of oxidative stress, was not systematically studied in PD. We aim to compare serum and cerebrospinal fluid (CSF) levels of UA, allantoin, and allantoin/UA ratio in de novo PD patients and controls, and evaluate their associations with clinical severity and the degree of substantia nigra degeneration in PD. We measured serum and CSF levels of UA, allantoin, and allantoin/UA ratio in 86 PD patients (33 females, mean age 57.9 (SD 12.6) years; CSF levels were assessed in 51 patients) and in 40 controls (19 females, 56.7 (14.1) years). PD patients were examined using Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Montreal Cognitive Assessment (MoCA), Scales for Outcomes in Parkinson Disease-Autonomic (SCOPA-AUT), the University of Pennsylvania Smell Identification Test (UPSIT), one-night video-polysomnography, and dopamine transporter single-photon emission computed tomography (DAT-SPECT). Serum allantoin and allantoin/UA ratio were significantly increased in the PD group compared to controls (p < 0.001 and p = 0.002, respectively). Allantoin/UA ratios in serum and CSF were positively associated with the SCOPA-AUT score (p = 0.005 and 0.031, respectively) and RBD presence (p = 0.044 and 0.028, respectively). In conclusion, serum allantoin and allantoin/UA ratio are elevated in patients with de novo PD. Allantoin/UA ratio in serum and CSF is associated with autonomic dysfunction and RBD presence, indicating that higher systemic oxidative stress occurs in PD patients with more diffuse neurodegenerative changes.

Serum proteins for monitoring and predicting visual function in patients with recent optic neuritis

It is unclear whether serum proteins can serve as biomarkers to reflect pathological changes and predict recovery in inflammation of optic nerve. We evaluated whether serum proteins could monitor and prognosticate optic neuritis (ON). We prospectively recruited consecutive patients with recent ON, classified as ON with anti-aquaporin-4 antibody (AQP4-ON), ON with anti-myelin oligodendrocyte glycoprotein antibody (MOG-ON), and double-seronegative ON (DSN-ON). Using ultrasensitive single-molecule array assays, we measured serum neurofilament light chain and glial fibrillary acidic protein (GFAP), and brain-derived neurotrophic factor (BDNF). We analyzed the markers according to disease group, state, severity, and prognosis. We enrolled 60 patients with recent ON (15 AQP4-ON; 14 MOG-ON; 31 DSN-ON). At baseline, AQP4-ON group had significantly higher serum GFAP levels than did other groups. In AQP4-ON group, serum GFAP levels were significantly higher in the attack state than in the remission state and correlated with poor visual acuity. As a prognostic indicator, serum BDNF levels were positively correlated with follow-up visual function in the AQP4-ON group (r = 0.726, p = 0.027). Serum GFAP reflected disease status and severity, while serum BDNF was identified as a prognostic biomarker in AQP4-ON. Serum biomarkers are potentially helpful for patients with ON, particularly those with AQP4-ON.

Cerebrospinal fluid sulfatide isoforms lack diagnostic utility in separating progressive from relapsing-remitting multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated demyelinating disorder of the central nervous system. The glycosphingolipid sulfatide, a lipid particularly enriched in the myelin sheath, has been shown to be involved the maintenance of this specific membrane structure. Sulfatide in cerebrospinal fluid (CSF) may reflect demyelination, a dominating feature of MS. We investigated the diagnostic utility of CSF sulfatide isoform levels to separate different courses or phenotypes of MS disease.

MATERIAL AND METHODS

This was a mono-center, cross-sectional study of relapsing-remitting MS (RRMS) (n = 45) and progressive MS (PMS) (n = 42) patients (consisting of primary PMS (n = 17) and secondary PMS (n = 25)) and healthy controls (n = 19). In total, 20 sulfatide isoforms were measured in CSF by liquid chromatography-mass spectrometry.

RESULTS

CSF total sulfatide concentrations, as well as CSF sulfatide isoform distribution, did not differ across the study groups, and their levels were independent of disease course/phenotype, disease duration, time to conversion to secondary PMS, age, and disability in MS patients.

CONCLUSION

CSF sulfatide isoforms lack diagnostic and prognostic utility as a biomarker for progressive MS.

Comparisons of 25 cerebrospinal fluid cytokines in a case-control study of 106 patients with recent-onset depression and 106 individually matched healthy subjects

BACKGROUND

Neuroinflammation has been suggested as a contributor to the pathophysiology of depression; however, large case-control studies investigating cytokine levels in the cerebrospinal fluid (CSF) from patients with recent-onset depression by multiplex analyses are missing.

METHODS

An individually matched (sex and age) prospective case-control study comparing patients with recent-onset depression to healthy controls. CSF was analyzed with the Mesoscale V-PLEX Neuroinflammation Panel 1.

OUTCOMES

comparisons of analyte levels in the CSF between groups with interleukin (IL)-6 and IL-8 as primary outcomes and 23 other cytokines as secondary outcomes.

RESULTS

We included 106 patients (84.0% outpatients) with recent-onset depression and 106 healthy controls. There were no significant differences in the primary outcomes IL-6 (relative mean difference (MD): 1.10; 95% confidence interval (CI) 0.93-1.30; p = 0.276) or IL-8 levels (MD: 1.05; 95% CI 0.96-1.16; p = 0.249) relative to healthy controls. IL-4 was 40% higher (MD: 1.40; 95% CI 1.14-1.72; p = 0.001), monocyte chemoattractant protein (MCP)-1 was 25% higher (MD: 1.25; 95% CI 1.06-1.47; p = 0.009) and macrophage inflammatory protein (MIP)-1β was 16% higher (MD: 1.16; 95% CI 1.02-1.33; p = 0.025) in patients with depression relative to healthy controls. However, only IL-4 was significantly elevated after correction for multiple testing of secondary outcomes (p = 0.025).

CONCLUSION

We found no significant differences in CSF levels of the co-primary outcomes IL-6 and IL-8, however, the higher CSF levels of IL-4, MCP-1 and MIP-1β among patients with recent-onset depression compared to healthy controls indicate a potential role of these cytokines in the neuroinflammatory response to depression.

Determinants of informal care time, distress, depression, and quality of life in care partners along the trajectory of Alzheimer's disease

Introduction

We evaluated determinants associated with care partner outcomes along the Alzheimer's disease (AD) stages.

Methods

We included n = 270 care partners of amyloid-positive patients in the pre-dementia and dementia stages of AD. Using linear regression analysis, we examined determinants of four care partner outcomes: informal care time, caregiver distress, depression, and quality of life (QoL).

Results

More behavioral symptoms and functional impairment in patients were associated with more informal care time and depressive symptoms in care partners. More behavioral symptoms were related with more caregiver distress. Spouse care partners spent more time on informal care and QoL was lower in female care partners. Behavioral problems and subtle functional impairment of the patient predisposed for worse care partner outcomes already in the pre-dementia stages.

Discussion

Both patient and care partner determinants contribute to the care partner outcomes, already in early disease stages. This study provides red flags for high care partner burden.

A blood mRNA panel that differentiates Alzheimer's disease from other dementia types

BACKGROUND

Messenger RNAs (mRNAs) have been reported to be associated with Alzheimer's disease (AD). In this study, we investigated whether plasma-based mRNAs could distinguish AD from cognitively normal controls and other types of dementia, including vascular dementia (VaD), Parkinson's disease dementia (PDD), behavioral variant frontotemporal dementia (bvFTD), and dementia with Lewy body (DLB).

METHODS

Plasma mRNA expression was measured in three independent datasets. Dataset 1 (n = 40; controls, 20; AD, 20) was used to identify the differentially expressed mRNAs. Dataset 2 (n = 122; controls: 60; AD: 62) was used to develop a diagnostic AD model using an mRNA panel. Furthermore, we applied the model to Dataset 3 (n = 334; control, 57; AD, 58; VaD, 55; PDD, 54; bvFTD, 55; DLB, 55) to verify its ability to identify AD and other types of dementia.

RESULTS

Dataset 1 showed 22 upregulated and 21 downregulated mRNAs. A panel of six mRNAs distinguished AD from the control group in Dataset 2. The panel was used to successfully differentiate AD from other types of dementia in Dataset 3.

CONCLUSIONS

An AD-specific panel of six mRNAs was created that can be used for AD diagnosis.

Cerebrospinal fluid lipoproteins inhibit α-synuclein aggregation by interacting with oligomeric species in seed amplification assays

BACKGROUND

Aggregation of α-synuclein (α-syn) is a prominent feature of Parkinson's disease (PD) and other synucleinopathies. Currently, α-syn seed amplification assays (SAAs) using cerebrospinal fluid (CSF) represent the most promising diagnostic tools for synucleinopathies. However, CSF itself contains several compounds that can modulate the aggregation of α-syn in a patient-dependent manner, potentially undermining unoptimized α-syn SAAs and preventing seed quantification.

METHODS

In this study, we characterized the inhibitory effect of CSF milieu on detection of α-syn aggregates by means of CSF fractionation, mass spectrometry, immunoassays, transmission electron microscopy, solution nuclear magnetic resonance spectroscopy, a highly accurate and standardized diagnostic SAA, and different in vitro aggregation conditions to evaluate spontaneous aggregation of α-syn.

RESULTS

We found the high-molecular weight fraction of CSF (> 100,000 Da) to be highly inhibitory on α-syn aggregation and identified lipoproteins to be the main drivers of this effect. Direct interaction between lipoproteins and monomeric α-syn was not detected by solution nuclear magnetic resonance spectroscopy, on the other hand we observed lipoprotein-α-syn complexes by transmission electron microscopy. These observations are compatible with hypothesizing an interaction between lipoproteins and oligomeric/proto-fibrillary α-syn intermediates. We observed significantly slower amplification of α-syn seeds in PD CSF when lipoproteins were added to the reaction mix of diagnostic SAA. Additionally, we observed a decreased inhibition capacity of CSF on α-syn aggregation after immunodepleting ApoA1 and ApoE. Finally, we observed that CSF ApoA1 and ApoE levels significantly correlated with SAA kinetic parameters in n = 31 SAA-negative control CSF samples spiked with preformed α-syn aggregates.

CONCLUSIONS

Our results describe a novel interaction between lipoproteins and α-syn aggregates that inhibits the formation of α-syn fibrils and could have relevant implications. Indeed, the donor-specific inhibition of CSF on α-syn aggregation explains the lack of quantitative results from analysis of SAA-derived kinetic parameters to date. Furthermore, our data show that lipoproteins are the main inhibitory components of CSF, suggesting that lipoprotein concentration measurements could be incorporated into data analysis models to eliminate the confounding effects of CSF milieu on α-syn quantification efforts.

Biobanking for Neurodegenerative Diseases: Challenge for Translational Research and Data Privacy

Biobanking has emerged as a strategic challenge to promote knowledge on neurological diseases, by the application of translational research. Due to the inaccessibility of the central nervous system, the advent of biobanks, as structure collecting biospecimens and associated data, are essential to turn experimental results into clinical practice. Findings from basic research, omics sciences, and in silico studies, definitely require validation in clinically well-defined cohorts of patients, even more valuable when longitudinal, or including preclinical and asymptomatic individuals. Finally, collecting biological samples requires a great effort to guarantee respect for transparency and protection of sensitive data of patients and donors. Since the European General Data Protection Regulation 2016/679 has been approved, concerns about the use of data in biomedical research have emerged. In this narrative review, we focus on the essential role of biobanking for translational research on neurodegenerative diseases. Moreover, we address considerations for biological samples and data collection, the importance of standardization in the preanalytical phase, data protection (ethical and legal) and the role of donors in improving research in this field.

Prospective evaluation of plasma phosphorylated tau in a real-life memory clinic in Thailand

INTRODUCTION

Despite the substantial accuracy of plasma p-tau in diagnosing Alzheimer's disease (AD) in research cohorts, data on real-life memory clinic patients are lacking.

METHODS

Memory clinic patients at their early symptomatic stages were prospectively enrolled to undergo routine clinical assessment, plasma p-tau181 quantification (Simoa), amyloid and tau-positron emission tomography (PET). The diagnostic performance of plasma p-tau181, neurocognitive specialists, and regional tau-PET were compared head-to-head using amyloid-PET as the reference standard.

RESULTS

Plasma p-tau181 has the area under the curve (AUC), sensitivity, specificity, and accuracy of 0.84 (95% confidence interval [CI] 0.73-0.94), 0.80 (95% CI 0.64-0.90), 0.75 (95% CI 0.51-0.90), and 0.78 (95% CI 0.65-0.88) for detecting amyloid-PET positivity in early symptomatic patients, respectively. The AUC of clinical diagnosis and tau-PET were 0.70 (95% CI 0.56-0.85) and 0.88 (95% CI 0.79-0.97), respectively.

DISCUSSION

Plasma p-tau181 also performed well in real-life memory clinic settings and its role in clinical practice is supported.

Phenotypic correlates of serum neurofilament light chain levels in amyotrophic lateral sclerosis

Objective

To investigate the relationship between serum levels of the neuroaxonal degeneration biomarker neurofilament light chain (NFL) and phenotype in ALS.

Materials and methods

Serum NFL (sNFL) concentration was quantified in 209 ALS patients and 46 neurologically healthy controls (NHCs).

Results

sNFL was clearly increased in ALS patients and discriminated them from NHCs with AUC = 0.9694. Among ALS patients, females had higher sNFL levels, especially in case of bulbar onset. sNFL was more increased in phenotypes with both upper (UMN) and lower motor neuron (LMN) signs, and particularly in those with UMN predominance, compared to LMN forms. At the same time, primary lateral sclerosis (PLS) had significantly lower levels compared to UMN-predominant ALS (AUC = 0.7667). sNFL correlated negatively with disease duration at sampling and ALSFRS-R score, positively with disease progression rate, differed among King’s stages, and was negatively associated with survival. It also correlated with clinical/neurophysiological indices of UMN and LMN dysfunction (Penn UMN Score, LMN score, MRC composite score, active spinal denervation score). On the contrary, sNFL was not associated with cognitive deficits nor with respiratory parameters. Notably, we found a negative correlation between sNFL and estimated glomerular filtration rate (eGFR).

Interpretation

We confirm that ALS is characterized by increased sNFL levels, whose main determinant is the rate of degeneration of both UMNs and LMNs. sNFL is a biomarker of only motor, not of extra-motor, disease. The negative correlation with kidney function might reflect varying renal clearance of the molecule and deserves further investigation before introducing sNFL measurement as routine test in clinical care of ALS patients.

Sphingolipids in Cerebrospinal Fluid and Plasma Lipoproteins of APOE4 Homozygotes and Non-APOE4 Carriers with Mild Cognitive Impairment versus Subjective Cognitive Decline

Background: Alzheimer’s disease (AD) patients display alterations in cerebrospinal fluid (CSF) and plasma sphingolipids. The APOE4 genotype increases the risk of developing AD. Objective: To test the hypothesis that the APOE4 genotype affects common sphingolipids in CSF and in plasma of patients with early stages of AD. Methods: Patients homozygous for APOE4 and non-APOE4 carriers with mild cognitive impairment (MCI; n = 20 versus 20) were compared to patients with subjective cognitive decline (SCD; n = 18 versus 20). Sphingolipids in CSF and plasma lipoproteins were determined by liquid-chromatography-tandem mass spectrometry. Aβ42 levels in CSF were determined by immunoassay. Results: APOE4 homozygotes displayed lower levels of sphingomyelin (SM; p = 0.042), SM(d18:1/18:0) (p = 0.026), and Aβ 42 (p < 0.001) in CSF than non-APOE4 carriers. CSF-Aβ 42 correlated with Cer(d18:1/18:0), SM(d18:1/18:0), and SM(d18:1/18:1) levels in APOE4 homozygotes (r > 0.49; p < 0.032) and with Cer(d18:1/24:1) in non-APOE4 carriers (r = 0.50; p = 0.025). CSF-Aβ 42 correlated positively with Cer(d18:1/24:0) in MCI (p = 0.028), but negatively in SCD patients (p = 0.019). Levels of Cer(d18:1/22:0) and long-chain SMs were inversely correlated with Mini-Mental State Examination score among MCI patients, independent of APOE4 genotype (r< –0.47; p < 0.039). Nevertheless, age and sex are stronger determinants of individual sphingolipid levels in CSF than either the APOE genotype or the cognitive state. In HDL, ratios of Cer(d18:1/18:0) and Cer(d18:1/22:0) to cholesterol were higher in APOE4 homozygotes than in non-APOE4 carriers (p = 0.048 and 0.047, respectively). Conclusion: The APOE4 genotype affects sphingolipid profiles of CSF and plasma lipoproteins already at early stages of AD. ApoE4 may contribute to the early development of AD through modulation of sphingolipid metabolism.

Disease characteristics of idiopathic transverse myelitis with serum neuronal and astroglial damage biomarkers

Despite its close association with CNS inflammatory demyelinating disorders (CIDDs), pathogenic characteristics of idiopathic transverse myelitis (ITM) remain largely unknown. Here, we investigated serum levels of neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) in patients with ITM to unravel the disease characteristics of ITM. We prospectively recruited 70 patients with ITM, 62 with AQP4 + NMOSD and 85 with RRMS-including 31 patients with acute TM attacks-along with 30 HCs. We measured sNfL and sGFAP levels using single-molecular arrays and compared these levels per lesion volume between the disease groups during attacks. Compared to HCs, ITM patients showed higher sNfL and sGFAP during acute attacks (sNfL: p < 0.001, sGFAP: p = 0.024), while those in remission (sNfL: p = 0.944, sGFAP: p > 0.999) did not, regardless of lesion extents and presence of multiple attacks. ITM patients demonstrated lower sGFAP/volume (p = 0.011) during acute attacks and lower sGFAP (p < 0.001) in remission compared to AQP4 + NMOSD patients. These findings suggest that both neuronal and astroglial damages occur in patients with acute ITM attacks at a similar level to those with RRMS, distinct from AQP4 + NMOSD. However, active neuroinflammatory process was not remarkable during remission in this cohort.

Protein interactors of 3-O sulfated heparan sulfates in human MCI and age-matched control cerebrospinal fluid

Heparan sulfates (HS) proteoglycans are commonly found on the cell surface and mediate many processes. Binding of HS ligands is determined by the sulfation code on the HS chain that can be N-/2-O/6-O- or 3-O-sulfated, generating heterogenous sulfation patterns. 3-O sulfated HS (3S-HS) play a role in several (patho)physiological processes such as blood coagulation, viral pathogenesis and binding and internalization of tau in Alzheimer's disease. However, few 3S-HS-specific interactors are known. Thus, our insight into the role of 3S-HS in health and disease is limited, especially in the central nervous system. Using human CSF, we determined the interactome of synthetic HS with defined sulfation patterns. Our affinity-enrichment mass spectrometry studies expand the repertoire of proteins that may interact with (3S-)HS. Validating our approach, ATIII, a known 3S-HS interactor, was found to require GlcA-GlcNS6S3S for binding, similar to what has been reported. Our dataset holds novel, potential HS and 3S-HS protein ligands, that can be explored in future studies focusing on molecular mechanisms that depend on 3S-HS in (patho)physiological conditions.

Serum Glial Fibrillary Acidic Protein Compared With Neurofilament Light Chain as a Biomarker for Disease Progression in Multiple Sclerosis

Importance

There is a lack of validated biomarkers for disability progression independent of relapse activity (PIRA) in multiple sclerosis (MS).

Objective

To determine how serum glial fibrillary acidic protein (sGFAP) and serum neurofilament light chain (sNfL) correlate with features of disease progression vs acute focal inflammation in MS and how they can prognosticate disease progression.

Design, Setting, and Participants

Data were acquired in the longitudinal Swiss MS cohort (SMSC; a consortium of tertiary referral hospitals) from January 1, 2012, to October 20, 2022. The SMSC is a prospective, multicenter study performed in 8 centers in Switzerland. For this nested study, participants had to meet the following inclusion criteria: cohort 1, patients with MS and either stable or worsening disability and similar baseline Expanded Disability Status Scale scores with no relapses during the entire follow-up; and cohort 2, all SMSC study patients who had initiated and continued B-cell-depleting treatment (ie, ocrelizumab or rituximab).

Exposures

Patients received standard immunotherapies or were untreated.

Main Outcomes and Measures

In cohort 1, sGFAP and sNfL levels were measured longitudinally using Simoa assays. Healthy control samples served as the reference. In cohort 2, sGFAP and sNfL levels were determined cross-sectionally.

Results

This study included a total of 355 patients (103 [29.0%] in cohort 1: median [IQR] age, 42.1 [33.2-47.6] years; 73 female patients [70.9%]; and 252 [71.0%] in cohort 2: median [IQR] age, 44.3 [33.3-54.7] years; 156 female patients [61.9%]) and 259 healthy controls with a median [IQR] age of 44.3 [36.3-52.3] years and 177 female individuals (68.3%). sGFAP levels in controls increased as a function of age (1.5% per year; P < .001), were inversely correlated with BMI (-1.1% per BMI unit; P = .01), and were 14.9% higher in women than in men (P = .004). In cohort 1, patients with worsening progressive MS showed 50.9% higher sGFAP levels compared with those with stable MS after additional sNfL adjustment, whereas the 25% increase of sNfL disappeared after additional sGFAP adjustment. Higher sGFAP at baseline was associated with accelerated gray matter brain volume loss (per doubling: 0.24% per year; P < .001) but not white matter loss. sGFAP levels remained unchanged during disease exacerbations vs remission phases. In cohort 2, median (IQR) sGFAP z scores were higher in patients developing future confirmed disability worsening compared with those with stable disability (1.94 [0.36-2.23] vs 0.71 [-0.13 to 1.73]; P = .002); this was not significant for sNfL. However, the combined elevation of z scores of both biomarkers resulted in a 4- to 5-fold increased risk of confirmed disability worsening (hazard ratio [HR], 4.09; 95% CI, 2.04-8.18; P < .001) and PIRA (HR, 4.71; 95% CI, 2.05-9.77; P < .001).

Conclusions and Relevance

Results of this cohort study suggest that sGFAP is a prognostic biomarker for future PIRA and revealed its complementary potential next to sNfL. sGFAP may serve as a useful biomarker for disease progression in MS in individual patient management and drug development.

LRRK2 Quantification in Cerebrospinal Fluid of Patients with Parkinson's Disease and Atypical Parkinsonian Syndromes

BACKGROUND

The alteration of leucine-rich repeat kinase 2 (LRRK2) kinase activity is thought to be involved in Parkinson's disease (PD) pathogenesis beyond familiar cases, and LRRK2 inhibitors are currently under investigation. Preliminary data suggest a relationship between LRRK2 alteration and cognitive impairment in PD.

OBJECTIVE

To investigate cerebrospinal fluid (CSF) LRRK2 levels in PD and other parkinsonian disorders, also correlating them with cognitive impairment.

METHODS

In this study, we retrospectively investigated by means of a novel highly sensitive immunoassay the levels of total and phosphorylated (pS1292) LRRK2 in CSF of cognitively unimpaired PD (n = 55), PD with mild cognitive impairment (n = 49), PD with dementia (n = 18), dementia with Lewy bodies (n = 12), atypical parkinsonian syndromes (n = 35), and neurological controls (n = 30).

RESULTS

Total and pS1292 LRRK2 levels were significantly higher in PD with dementia with respect to PD with mild cognitive impairment and PD, and also showed a correlation with cognitive performances.

CONCLUSIONS

The tested immunoassay may represent a reliable method for assessing CSF LRRK2 levels. The results appear to confirm an association of LRRK2 alteration with cognitive impairment in PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Intrathecal versus Peripheral Inflammatory Protein Profile in MS Patients at Diagnosis: A Comprehensive Investigation on Serum and CSF

Intrathecal inflammation plays a key role in the pathogenesis of multiple sclerosis (MS). To better elucidate its relationship with peripheral inflammation, we investigated the correlation between cerebrospinal fluid (CSF) and serum levels of 61 inflammatory proteins. Paired CSF and serum samples were collected from 143 treatment-naïve MS patients at diagnosis. A customized panel of 61 inflammatory molecules was analyzed by a multiplex immunoassay. Correlations between serum and CSF expression levels for each molecule were performed by Spearman's method. The expression of sixteen CSF proteins correlated with their serum expression (p-value < 0.001): only five molecules (CXCL9, sTNFR2, IFNα2, Pentraxin-3, and TSLP) showed a Rho value >0.40, suggesting moderate CSF/serum correlation. No correlation between inflammatory serum patterns and Q_alb was observed. Correlation analysis of serum expression levels of these sixteen proteins with clinical and MRI parameters pinpointed a subset of five molecules (CXCL9, sTNFR2, IFNα2, IFNβ, and TSLP) negatively correlating with spinal cord lesion volume. However, following FDR correction, only the correlation of CXCL9 remained significant. Our data support the hypothesis that the intrathecal inflammation in MS only partially associates with the peripheral one, except for the expression of some immunomodulators that might have a key role in the initial MS immune response.

High serum neurofilament light chain levels correlate with brain atrophy and physical disability in multiple sclerosis

BACKGROUND AND PURPOSE

Serum neurofilament light chain (sNfL) is a promising biomarker of neuroaxonal damage in persons with multiple sclerosis (pwMS). In cross-sectional studies, sNfL has been associated with disease activity and brain magnetic resonance imaging (MRI) changes; however, it is still unclear to what extent in particular high sNfL levels impact on subsequent disease evolution.

METHODS

sNfL was quantified by an ultrasensitive single molecule array (Simoa) in 199 pwMS (median age = 34.2 years, 64.3% female) and 49 controls. All pwMS underwent 3-T MRI to assess global and compartmental normalized brain volumes, T2-lesion load, and cortical mean thickness. Follow-up data and serum samples were available in 144 pwMS (median follow-up time = 3.8 years). Linear and binary logistic models were used to estimate the independent contribution of sNfL for changes in MRI and Expanded Disability Status Scale (EDSS). Age-corrected sNfL z-scores from a normative database of healthy controls were used for sensitivity analyses.

RESULTS

High sNfL levels at baseline were associated with atrophy measures of the whole brain (standardized beta coefficient βj = -0.352, p < 0.001), white matter (βj = -0.229, p = 0.007), thalamus (βj = -0.372, p = 0.004), and putamen (βj = -1.687, p = 0.012). pwMS with high levels of sNfL at baseline and follow-up had a greater risk of EDSS worsening (p = 0.007).

CONCLUSIONS

Already single time point elevation of sNfL has a distinct effect on brain volume changes over a short-term period, and repeated high levels of sNfL indicate accumulating physical disability. Serial assessment of sNfL may provide added value in the clinical management of pwMS.

Concentration gradients of monoamines, their precursors and metabolites in serial lumbar cerebrospinal fluid of neurologically healthy patients determined with a novel LC-MS/MS technique

BACKGROUND

Potential biomarkers for neuropsychiatric disorders are cerebrospinal fluid (CSF) monoamines and their corresponding precursors and metabolites. During CSF sampling, CSF flows towards the lumbar sampling site from more cranial regions. To compare the results of studies in which different CSF volumes were acquired, it is important to know if ventricular-lumbar concentration gradients exist. This has only been addressed for a few biogenic amines, and almost exclusively in neurologically unwell patients due to the burden of a lumbar puncture (necessary to obtain CSF). The aim of our study was to determine if concentration gradients exist for routinely measured CSF constituents and biogenic amines in neurologically healthy patients. We applied a novel ultrasensitive liquid chromatography mass spectrometry (LC-MS/MS) method for the simultaneous quantification of multiple monoamines, precursors and metabolites in CSF and plasma.

METHODS

CSF and blood samples were collected from twenty neurologically healthy patients undergoing spinal anaesthesia. Ten mL of lumbar CSF was collected in five consecutive two mL fractions. We determined leucocyte and erythrocyte counts, glucose, albumin and protein concentrations and quantified monoamines, precursors and metabolites on each of the fractions using LC-MS/MS.

RESULTS

In twenty patients (60% male; median age: 46 years), dopamine, DOPAC, 3-MT, HVA, noradrenaline, normetanephrine and 5-HIAA concentrations increased from the first to the last CSF fraction (all p < 0.001). CSF adrenaline concentrations were below the detection limit, whereas serotonin measurements were regarded as unreliable. Albumin and total protein levels decreased significantly across CSF fractions.

CONCLUSIONS

A ventricular-lumbar CSF concentration gradient existed for most of the investigated analytes. This is a novel finding for dopamine, noradrenaline, 3-MT and normetanephrine. These results contribute to the understanding of the neurobiology and underline the importance of standardized procedures for CSF handling to allow comparisons between studies.

Diagnosis of cerebral malaria: Tools to reduce Plasmodium falciparum associated mortality

Cerebral malaria (CM) is a major cause of mortality in Plasmodium falciparum (Pf) infection and is associated with the sequestration of parasitised erythrocytes in the microvasculature of the host's vital organs. Prompt diagnosis and treatment are key to a positive outcome in CM. However, current diagnostic tools remain inadequate to assess the degree of brain dysfunction associated with CM before the window for effective treatment closes. Several host and parasite factor-based biomarkers have been suggested as rapid diagnostic tools with potential for early CM diagnosis, however, no specific biomarker signature has been validated. Here, we provide an updated review on promising CM biomarker candidates and evaluate their applicability as point-of-care tools in malaria-endemic areas.

A Group of Long Non-coding RNAs in Blood Acts as a Specific Biomarker of Alzheimer's Disease

Long non-coding RNAs (lncRNAs) have been identified to be involved in the pathogenesis of Alzheimer's disease (AD). In this study, we evaluated whether lncRNAs can be used to discriminate AD patients from controls and patients with other dementias, such as vascular, Parkinson's disease, behavioral variant frontotemporal, and dementia with Lewy body. In this study, we used three datasets to measure the blood lncRNA levels. A pilot study (dataset 1, n = 40; controls, 20; AD, 20) was used to screen for differentially expressed lncRNAs. Dataset 2 (n = 174; controls, 86; AD, 88) was used to identify a lncRNA panel for the diagnostic model. Dataset 3 (n = 333; control, 60; AD, 54; vascular dementia, 53; Parkinson's disease dementia, 55; behavioral variant frontotemporal dementia, 56; and dementia with Lewy body, 55) was used to validate the diagnostic model. In dataset 1, 12 upregulated and 15 downregulated lncRNAs were identified. In dataset 2, a panel of seven lncRNAs was found to have the ability to differentiate AD patients from controls. Finally, this panel was applied to dataset 3 to successfully distinguish AD from other dementias. This study proposes a panel of seven lncRNAs as specific and promising biomarker for AD diagnosis.

Effects of acute aerobic exercise on cytokines, klotho, irisin, and vascular endothelial growth factor responses in rheumatoid arthritis patients

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that causes cartilage and bone damage as well as disability.  AIMS : The aim of this study was to examine the effects of acute aerobic exercise on cytokines such as serum interleukin-6 (IL-6), interleukin-1β (IL-1β), Tumor Necrosis Factor-α (TNF-α) and irisin, vascular endothelial growth factor(VEGF) and klotho in RA patients.  METHODS: Forty RA patient and 40 healthy volunteers of the same age participated in this study. All participants walked on the treadmill for 30 minutes at 60-80% of maximal heart rate. Blood samples were taken before and immediately after the exercise. Serum levels of IL-6, IL1β, TNF-α and irisin, VEGF and klotho were measured by enzyme-linked immunosorbent analysis.  RESULTS: Baseline levels of inflammatory cytokines, irisin, VEGF and klotho were found to be higher in RA patients compared to the control group. In both groups, there was an increase in serum klotho levels after exercise compared to baseline (p<0.05), while a decrease in IL1β, TNF-α levels were observed. While serum VEGF level decreased in RA group, it increased in the control group(p<0.05). Irisin levels decreased in both groups. IL-6 level did not change in the control group, while it increased in RA group. A single exercise session had an acute anti-inflammatory effect in RA patients.

CONCLUSION

It can be concluded that acute aerobic exercise can be beneficial for patients with RA through cytokine, irisin, klotho and VEGF levels, and also it can be safely implemented to the RA rehabilitation program for additional anti-inflammatory effects. Trial registration ClinicalTrials.gov: NCT04439682.

Cerebrospinal fluid kappa free light chains for the diagnosis of multiple sclerosis: A consensus statement

Cerebrospinal fluid (CSF) analysis is of utmost importance for diagnosis and differential diagnosis of patients with suspected multiple sclerosis (MS). Evidence of intrathecal immunoglobulin G (IgG) synthesis proves the inflammatory nature of the disease, increases diagnostic certainty and substitutes for dissemination in time according to current diagnostic criteria. The gold standard to determine intrathecal IgG synthesis is the detection of CSF-restricted oligoclonal bands (OCBs). However, advances in laboratory methods brought up κ-free light chains (FLCs) as a new biomarker, which are produced in excess over intact immunoglobulins and accumulate in CSF in the case of central nervous system-derived inflammation. Overwhelming evidence showed a high diagnostic accuracy of intrathecal κ-FLC synthesis in MS with sensitivity and specificity of approximately 90% similar to OCB. κ-FLCs have advantages as its detection is fast, easy, cost-effective, reliable, rater-independent and returning quantitative results which might also improve the value of predicting MS disease activity. An international panel of experts in MS and CSF diagnostics developed a consensus of all participants. Six recommendations are given for establishing standard CSF evaluation in patients suspected of having MS. The panel recommended to include intrathecal κ-FLC synthesis in the next revision of MS diagnostic criteria as an additional tool to measure intrathecal immunoglobulin synthesis.

PSEN2 and ABCA7 variants causing early-onset preclinical pathological changes in Alzheimer's disease: a case report and literature review

BACKGROUND

Alzheimer's disease (AD) is a debilitating and highly heritable neurodegenerative disease. Early-onset AD (EOAD) was defined as AD occurring before age 65. Although it has a high genetic risk, EOAD due to PSEN2 variation is very rare. ABCA7 is an important risk gene for AD. Previously reported cases mainly carried variations in a single pathogenic or risk gene. METHODS AND RESULTS: In this study, we report a 35-year-old female carrying variants in both the PSEN2 gene (c.640G > T p.V214L) and ABCA7 gene (c.2848G > A p.V950M). Four previously reported cases carried PSEN2 V214L, and no reported cases carried ABCA7 V950M. She had a history of migraine, patent foramen ovale, spontaneous subarachnoid hemorrhage without aneurysm, and multiple cerebral microhemorrhages. Her MMSE score was 24/30, and her MoCA score was 22/30. The concentration of Aβ42 and the ratio of Aβ42 to Aβ40 in cerebral spinal fluid were obviously decreased. Published variants of PSEN2 and ABCA7 in PubMed were reviewed, and the patients' characteristics were summarized and compared to provide information for the clinical diagnosis of AD.

CONCLUSIONS

It is necessary to conduct genetic screening in cases with atypical manifestations.

Robustness of CSF Aβ42/40 and Aβ42/P-tau181 measured using fully automated immunoassays to detect AD-related outcomes

INTRODUCTION

This study investigated the comparability of cerebrospinal fluid (CSF) cutoffs for Elecsys immunoassays for amyloid beta (Aβ)42/Aβ40 or Aβ42/phosphorylated tau (p-tau)181 and the effects of measurement variability when predicting Alzheimer's disease (AD)-related outcomes (i.e., Aβ-positron emission tomography [PET] visual read and AD neuropathology).

METHODS

We studied 750 participants (BioFINDER study, Alzheimer's Disease Neuroimaging Initiative [ADNI], and University of California San Francisco [UCSF]). Youden's index was used to identify cutoffs and to calculate accuracy (Aβ-PET visual read as outcome). Using longitudinal variability in Aβ-negative controls, we identified a gray zone around cut-points where the risk of an inconsistent predicted outcome was >5%.

RESULTS

For Aβ42/Aβ40, cutoffs across cohorts were <0.059 (BioFINDER), <0.057 (ADNI), and <0.058 (UCSF). For Aβ42/p-tau181, cutoffs were <41.90 (BioFINDER), <39.20 (ADNI), and <46.02 (UCSF). Accuracy was ≈90% for both Aβ42/Aβ40 and Aβ42/p-tau181 using these cutoffs. Using Aβ-PET as an outcome, 8.7% of participants fell within a gray zone interval for Aβ42/Aβ40, compared to 4.5% for Aβ42/p-tau181. Similar findings were observed using a measure of overall AD neuropathologic change (7.7% vs. 3.3%). In a subset with CSF and plasma Aβ42/40, the number of individuals within the gray zone was ≈1.5 to 3 times greater when using plasma Aβ42/40.

DISCUSSION

CSF Aβ42/p-tau181 was more robust to the effects of measurement variability, suggesting that it may be the preferred Elecsys-based measure in clinical practice and trials.

Cerebrospinal fluid β-synuclein as a synaptic biomarker for preclinical Alzheimer's disease

INTRODUCTION

β-synuclein (β-syn) is a presynaptic protein, whose cerebrospinal fluid (CSF) levels are increased in patients with Alzheimer's diseases (AD) showing mild cognitive impairment (MCI) and dementia (dem). Here, we aimed to investigate CSF β-syn in subjects at different AD stages, including preclinical AD (pre-AD), and to compare its behaviour with another synaptic biomarker, α-synuclein (α-syn), and two biomarkers of neuro-axonal damage, namely neurofilament light chain protein (NfL) and total tau protein (t-tau).

METHODS

We measured β-syn, α-syn, t-tau and NfL in CSF of 75 patients with AD (pre-AD n=17, MCI-AD n=28, dem-AD n=30) and 35 controls (subjective memory complaints, SMC-Ctrl n=13, non-degenerative neurological disorders, Dis-Ctrl n=22).

RESULTS

CSF β-syn, α-syn, t-tau were significantly elevated in pre-AD patients compared with controls (p<0.0001, p=0.02 and p=0.0001, respectively), while NfL only increased in dem-AD (p=0.001). Pre-AD cases showed lower t-tau concentrations than MCI-AD (p=0.04) and dem-AD (p=0.01). CSF β-syn had the best diagnostic performance for the discrimination of pre-AD subjects from all controls (area under the curve, AUC=0.97) and from SMC-Ctrl subjects (AUC=0.99).

DISCUSSION

CSF β-syn increases in the whole AD continuum since the preclinical stage and represents a promising biomarker of synaptic damage in AD.

Teriflunomide Concentrations in Cerebrospinal Fluid and Plasma in Patients with Multiple Sclerosis: A Pharmacokinetic Study

BACKGROUND

Teriflunomide is a disease modifying treatment (DMT) approved for relapsing-remitting multiple sclerosis (RRMS) in adults and children. It reduces lymphocyte proliferation by inhibiting the mitochondrial enzyme dihydroorotate dehydrogenase (DHODH) and thereby the pyrimidine synthesis. Although most DMTs in multiple sclerosis (MS) modulate or inhibit the immune system in the periphery, the efficacy may improve if the agent also targets immune activity within the central nervous system (CNS), acts as a neuro-protective and enhances neuro-regeneration. The objective of this study was to determine the passage of teriflunomide over the blood-cerebrospinal fluid barrier (BCSFB).

METHODS

Plasma and cerebrospinal fluid (CSF) teriflunomide concentrations were determined at steady state in 12 patients with RRMS, treated with oral teriflunomide 14 mg once daily. Included patients were all clinically stable without relapse or disability worsening within 6 months prior from baseline and were on no other immune modulating or immunosuppressive drugs.

RESULTS

The mean teriflunomide concentrations in plasma and CSF were 38775 (SEM ± 7256) ng/mL and 68 (SEM ± 15) ng/mL, respectively. The passage over the BCSFB was 0.17 % (SEM ± 0.01). While no correlation was found between the function of the BCSFB assessed with the albumin ratio and the CSF teriflunomide concentration, the CSF and plasma teriflunomide concentrations were highly correlated (r_s = 0.90, < 0.0001).

CONCLUSIONS

Further studies are warranted to determine if the obtained CSF teriflunomide concentration reflects that in the CNS and is able to influence inflammatory and degenerative processes within the CNS.

CSF CXCL13 and Chitinase 3-like-1 Levels Predict Disease Course in Relapsing Multiple Sclerosis

Several biomarkers from multiple sclerosis (MS) patients' biological fluids have been considered to support diagnosis, predict disease course, and evaluate treatment response. In this study, we assessed the CSF concentration of selected molecules implicated in the MS pathological process. To investigate the diagnostic and prognostic significance of CSF concentration of target candidate biomarkers in both relapsing (RMS, n = 107) and progressive (PMS, n = 18) MS patients and in other inflammatory (OIND, n = 10) and non-inflammatory (ONIND, n = 15) neurological disorders. We measured the CSF concentration of APRIL, BAFF, CHI3L1, CCL-2, CXCL-8, CXCL-10, CXCL-12, CXCL-13 through a Luminex Assay. MS patients were prospectively evaluated, and clinical and radiological activity were recorded. CHI3L1 and CXCL13 CSF levels were significantly higher in both MS groups compared to control groups, while CCL2, BAFF, and APRIL concentrations were lower in RMS patients compared to PMS and OIND. Considering RMS patients with a single demyelinating event, higher concentrations of CHI3L1, CXCL10, CXCL12, and CXCL13 were recorded in patients who converted to clinically defined MS(CDMS). RMS patients in the CXCL13 and CHI3L1 high concentration group had a significantly higher risk of relapse (HR 12.61 and 4.57), MRI activity (HR 7.04 and 2.46), and of any evidence of disease activity (HR 12.13 and 2.90) during follow-up. CSF CXCL13 and CHI3L1 levels represent very good prognostic biomarkers in RMS patients, and therefore can be helpful in the treatment choice. Higher CSF concentrations of neuro-inflammatory biomarkers were associated with a higher risk of conversion to CDMS in patients with a first clinical demyelinating event. Differential CSF BAFF and APRIL levels between RMS and PMS suggest a different modulation of B-cells pathways in the different phases of the disease.

Serum glial fibrillary acidic protein is sensitive to acute but not chronic tissue damage in cerebral small vessel disease

BACKGROUND

Serum glial fibrillary acidic protein (sGFAP) has been proposed as a biomarker in various neurological diseases but has not yet been systematically investigated in patients with cerebral small vessel disease (CSVD). We explored whether sGFAP levels are increased in stroke patients with MRI-confirmed recent small subcortical infarcts (RSSI) and analyzed the subsequent course and determinants of sGFAP longitudinally.

METHODS

In a prospectively-collected cohort of stroke patients with a single RSSI (n = 101, mean age: 61 years, 73% men), we analyzed brain MRI and sGFAP using a SIMOA assay at baseline and at 3- and 15-months post-stroke. Community-dwelling age- and sex-matched individuals (n = 51) served as controls.

RESULTS

RSSI patients had higher baseline sGFAP levels compared to controls (median: 187.4 vs. 118.3 pg/ml, p < 0.001), with no influence of the time from stroke symptom onset to baseline blood sampling (median 5 days, range 1-13). At the 3- and 15-months follow-up, sGFAP returned to control levels. While baseline sGFAP correlated with larger infarct size (r_s = 0.28, p = 0.01), neither baseline nor follow-up sGFAP levels were associated with chronic CSVD-related lesions (white matter hyperintensities, lacunes, microbleeds) after adjusting for age, sex and hypertension. Furthermore, sGFAP levels did not relate to the occurrence of new vascular brain lesions on follow-up MRI.

CONCLUSIONS

sGFAP is increased in patients with CSVD-related stroke and correlates with the size of the RSSI. However, sGFAP levels were not related to chronic neuroimaging features or progression of CSVD, suggesting that sGFAP is sensitive to acute but not chronic cerebrovascular tissue changes in this condition.

Development of an ultrasensitive microfluidic assay for the analysis of Glial fibrillary acidic protein (GFAP) in blood

Introduction: A rapid and reliable detection of glial fibrillary acidic protein (GFAP) in biological samples could assist in the diagnostic evaluation of neurodegenerative disorders. Sensitive assays applicable in the routine setting are needed to validate the existing GFAP tests. This study aimed to develop a highly sensitive and clinically applicable microfluidic immunoassay for the measurement of GFAP in blood. Methods: A microfluidic GFAP assay was developed and validated regarding its performance. Subsequently, serum and cerebrospinal fluid (CSF) of Alzheimer's disease (AD), Multiple Sclerosis (MS) and control patients were analyzed with the established assay, and levels were compared to the commercial GFAP Simoa discovery kit. Results: The developed GFAP assay showed a good performance with a recovery of 85% of spiked GFAP in serum and assay variations below 15%. The established assay was highly sensitive with a calculated lower limit of quantification and detection of 7.21 pg/mL and 2.37 pg/mL, respectively. GFAP levels were significantly increased in AD compared to control patients with advanced age (p = 0.002). However, GFAP levels revealed no significant increase in MS compared to control patients in the same age range (p = 0.140). Furthermore, serum GFAP levels evaluated with the novel microfluidic assay strongly correlated with Simoa concentrations (r = 0.88 (95% CI: 0.81-0.93), p < 0.0001). Conclusion: We successfully developed a sensitive and easy-to-use microfluidic assay to measure GFAP in blood. Furthermore, we could confirm previous findings of elevated GFAP levels in AD by applying the assay in a cohort of clinically characterized patients.

Life satisfaction across the entire trajectory of Alzheimer's disease: A mediation analysis

Introduction

We studied life satisfaction across Alzheimer's disease (AD) stages and studied mobility and meaningful activities as mediators of the associations between these AD stages and life satisfaction.

Methods

In this cross-sectional study, we included n = 269 amyloid-positive patients with subjective cognitive decline (SCD), mild cognitive impairment (MCI), and AD dementia from the Amsterdam Dementia Cohort. Life satisfaction was measured with the satisfaction with life scale. The mediating role of transportation, work, sports, and hobbies on life satisfaction was examined in single and multiple mediator models.

Results

Patients with dementia are less satisfied with life compared to SCD and MCI. These differences in life satisfaction are explained by reduced participation in meaningful activities, which in turn, was largely attributable to decreased transportation use.

Discussion

Our findings suggest that improving access to transportation, therewith allowing participation in meaningful activities help to maintain life satisfaction and may be an important target for intervention.

Redox State of Human Serum Albumin in Multiple Sclerosis: A Pilot Study

Like in many other pathologies, oxidative stress is involved in the development of neurodegenerative disorders. Human serum albumin (HSA) is the main protein in different body fluids including cerebrospinal fluid (CSF). By its redox state in terms of cysteine-34, albumin serves as marker for oxidative burden. We aimed to evaluate the redox state of HSA in patients with multiple sclerosis in serum and CSF in comparison to controls to identify possible correlations with disease activity and severity. Samples were stored at -70 °C until analysis by HPLC for the determination of albumin redox state in terms of the fractions of human mercaptalbumin (HMA), human nonmercaptalbumin1 (HNA1), and human nonmercaptalbumin2 (HNA2). Albumin in CSF showed significantly higher fractions of the reduced form HMA and decreased HNA1 and HNA2. There was no difference between albumin redox states in serum of patients and controls. In CSF of patients HNA2 showed a trend to higher fractions compared to controls. Albumin redox state in serum was associated with physical disability in remission while albumin redox state in CSF was related to disease activity. Thus, albumin redox state in serum and CSF of patients in relation to disease condition merits further investigation.

Proteomic profiling of circulating plasma exosomes reveals novel biomarkers of Alzheimer's disease

BACKGROUND

Neuronal- and astrocyte-derived exosomes have been identified as an optimal source for screening biomarkers for Alzheimer's disease (AD). However, few studies focus on the bulk exosome population isolated from plasma of AD. This study investigated whether proteins in bulk exosomes can aid in the diagnosis of AD.

METHODS

The plasma exosomes were collected by ultracentrifuge. Protein samples were extracted from exosomes. Cerebrospinal fluid levels of amyloid β (Aβ)42 and phosphorylated tau (P-tau)181 were measured for diagnostic purposes. A pilot study (controls, 20; AD, 20) followed by a second dataset (controls, 56; AD, 58) was used to establish a diagnostic model of AD. Mass spectrometry-based proteomics was performed to profile the plasma exosomal proteome. Parallel reaction monitoring was used to further confirm the differentially expressed proteins.

RESULTS

In total, 328 proteins in plasma exosomes were quantified. Among them, 31 proteins were altered in AD patients, and 12 were validated. The receiver operating characteristic curve analysis revealed a combination of six proteins (upregulated: Ig-like domain-containing protein (A0A0G2JRQ6), complement C1q subcomponent subunit C (C1QC), complement component C9 (CO9), platelet glycoprotein Ib beta chain (GP1BB), Ras suppressor protein 1 (RSU1); downregulated: disintegrin and metalloproteinase domain 10 (ADA10)) has the capacity to differentiate AD patients from healthy controls with high accuracy. Linear correlation analysis showed that the combination was significantly correlated with cognitive performance.

CONCLUSIONS

The combination of plasma exosomal proteins A0A0G2JRQ6, C1QC, CO9, GP1BB, RSU1, and ADA10 acts as a novel candidate biomarker to differentiate AD patients from healthy individuals.

Biomarkers of demyelination and axonal damage are decreased after autologous hematopoietic stem cell transplantation for multiple sclerosis

BACKGROUND

Autologous hematopoietic stem cell transplantation (aHSCT) has seen increased use for relapsing-remitting multiple sclerosis (RRMS) in recent years. It is considered one of the most effective treatments for RRMS and has been associated with improvement in disability and prolonged remission. This suggests that the tissue-injuring disease process may have been altered by aHSCT. To assess whether this hypothesis is correct, we performed a study of three commonly used cerebrospinal fluid biomarkers of tissue damage.

METHODS

In this single center study, 63 patients treated with aHSCT at Uppsala University Hospital between January 1st 2012 and January 31st 2019 were screened for participation. A control group consisting of volunteers without neurologic disease were included as a reference. Cerebrospinal fluid concentrations of neurofilament light (NFL), myelin basic protein (MBP) and glial acidic fibrillary protein (GFAp) were determined using ELISA and a multiplex proteomics platform from Meso Scale Discovery.

RESULTS

Forty-three patients with a mean age of 31 and a median follow-up time of 3.9 years were included. Their median baseline expanded disability status scale (EDSS) score was 3.5 and the annualized relapse rate in the year preceding aHSCT was 1.6. At baseline the proportion of patients with values above the upper limit of normal was 67% for NFL, 63% for MBP and 16% for GFAp. At 5-year follow-up, the proportion of patients with values above the upper limit of normal was 12% for NFL, 12% for MBP and 25% for GFAp. The mean concentration of NFL decreased from 920 pg/mL at baseline to 270 pg/mL at 5-year follow-up (p < 0.001); MBP decreased from 1500 to 680 pg/mL (p < 0.001); whereas the mean concentration of GFAp was unchanged.

CONCLUSION

In a majority of patients, biomarkers of demyelination and axonal damage reached normal values within five years from treatment with aHSCT.

Plasma TDP-43 Reflects Cortical Neurodegeneration and Correlates with Neuropsychiatric Symptoms in Huntington's Disease

PURPOSE

Huntington's disease (HD) is a monogenic neurodegenerative disease with no effective treatment currently available. The pathological hallmark of HD is the aggregation of mutant huntingtin in the medium spiny neurons of the striatum, leading to severe subcortical atrophy. Cortical degeneration also occurs in HD from its very early stages, although its biological origin is poorly understood. Among the possible pathological mechanisms that could promote cortical damage in HD, the in vivo study of TDP-43 pathology remains to be explored, which was the main objective of this work.

METHODS

We investigated the clinical and structural brain correlates of plasma TDP-43 levels in a sample of 36 HD patients. Neuroimaging alterations were assessed both at the macrostructural (cortical thickness) and microstructural (intracortical diffusivity) levels. Importantly, we controlled for mutant huntingtin and tau biomarkers in order to assess the independent role of TDP-43 in HD neurodegeneration.

RESULTS

Plasma TDP-43 levels in HD specifically correlated with the presence and severity of apathy (p = 0.003). The TDP-43 levels also reflected cortical thinning and microstructural degeneration, especially in frontal and anterior-temporal regions (p < 0.05 corrected). These TDP-43-related brain alterations correlated, in turn, with the severity of cognitive, motor and behavioral symptoms.

CONCLUSION

Our results suggest that the presence of TDP-43 pathology in HD has an independent contribution to the severity of neuropsychiatric symptoms and frontotemporal degeneration. These findings point out the importance of TDP-43 as an additional pathological process to be taken into consideration in this devastating disorder.

Cerebrospinal Fluid Alpha-Synuclein Improves the Differentiation between Dementia with Lewy Bodies and Alzheimer's Disease in Clinical Practice

Background: Alpha-synuclein, abnormally aggregated in Dementia with Lewy Bodies (DLB), could represent a potential biomarker to improve the differentiation between DLB and Alzheimer’s disease (AD). Our main objective was to compare Cerebrospinal Fluid (CSF) alpha-synuclein levels between patients with DLB, AD and Neurological Control (NC) individuals. Methods: In a monocentric retrospective study, we assessed CSF alpha-synuclein concentration with a validated ELISA kit (ADx EUROIMMUN) in patients with DLB, AD and NC from a tertiary memory clinic. Between-group comparisons were performed, and Receiver Operating Characteristic analysis was used to identify the best CSF alpha-synuclein threshold. We examined the associations between CSF alpha-synuclein, other core AD CSF biomarkers and brain MRI characteristics. Results: We included 127 participants (mean age: 69.3 ± 8.1, Men: 41.7%). CSF alpha-synuclein levels were significantly lower in DLB than in AD (1.28 ± 0.52 ng/mL vs. 2.26 ± 0.91 ng/mL, respectively, p < 0.001) without differences due to the stage of cognitive impairment. The best alpha-synuclein threshold was characterized by an Area Under the Curve = 0.85, Sensitivity = 82.0% and Specificity = 76.0%. CSF alpha-synuclein was associated with CSF AT(N) biomarkers positivity (p < 0.01) but not with hippocampal atrophy or white matter lesions. Conclusion: CSF Alpha-synuclein evaluation could help to early differentiate patients with DLB and AD in association with existing biomarkers.

sNFL applicability as additional monitoring tool in natalizumab extended interval dosing regimen for RRMS patients

INTRODUCTION

Extended interval dosing (EID) of Natalizumab (NAT) has been proposed to reduce progressive multifocal leukoencephalopathy (PML) risk associated with standard interval dosing (SID) in people with multiple sclerosis (MS). Previous studies have suggested that NAT effectiveness is maintained in the great majority of patients who switch from SID to EID; monitoring of disease activity is currently based exclusively on clinical and MRI parameters. Frequent MRI are expensive and not always applicable, underlining the need for biological markers able to detect central nervous system lesions. Serum Neurofilament-light chain (sNFL) currently represents the most promising biomarker of disease activity, prognosis and treatment response in MS, and their clinical suitability is increasingly evident. The objective of the present study is to assess the applicability of sNFL as additional/alternative measure of treatment efficacy during EID regimen.

METHODS

We measured sNFL by Simoa technology in longitudinal samples from 63 Relapsing Remitting (RR) MS patients switched from SID to EID.

INCLUSION CRITERIA

diagnosis of RRMS, age 18-60 years; NAT SID for at least 12 months; NEDA-3 (no evidence of disease activity) for at least 12 months; availability of at least 2 serum samples collected 6 months apart. Patients' follow-up time during EID was at least 12 months and 2 blood samples were collected after at least 6 and 12 months. Clinical examination was performed before each infusion, while MRI 6 and 12 months after NAT initiation and according to PML risk during the whole study.

RESULTS

No patients showed clinical or MRI activity during the whole follow-up. sNFL levels measured during SID and EID were comparable, without significant difference between groups. The effect of EID on NFL levels did not show significant effects (LMM, p> 0.05) and sNFL levels did not vary with time during SID or EID protocols (LMM, p> 0.05). Intra-individual sNFL levels demonstrated overall stability during SID and EID (median CV=11% between SID and EID samples). According to our previously published reference values, sNFL levels were in the normal range in all samples, both during SID and EID.

CONCLUSIONS

Our results suggest that sNFL quantification can be used as an alternative/additional approach to MRI in managing individual patients. The present work provides a new clinical application of sNFL to monitor NAT efficacy.