Blood β-Synuclein and Neurofilament Light Chain During the Course of Prion Disease

5-Repurposed Drug Candidates Identified in Motor Neurons and Muscle Tissues with Amyotrophic Lateral Sclerosis by Network Biology and Machine Learning Based on Gene Expression

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that leads to motor neuron degeneration, muscle weakness, and respiratory failure. Despite ongoing research, effective treatments for ALS are limited. This study aimed to apply network biology and machine learning (ML) techniques to identify novel repurposed drug candidates for ALS. In this study, we conducted a meta-analysis using 4 transcriptome data in ALS patients (including motor neuron and muscle tissue) and healthy controls. Through this analysis, we uncovered common shared differentially expressed genes (DEGs) separately for motor neurons and muscle tissue. Using common DEGs as proxies, we identified two distinct clusters of highly clustered differential co-expressed cluster genes: the 'Muscle Tissue Cluster' for muscle tissue and the 'Motor Neuron Cluster' for motor neurons. We then evaluated the performance of the nodes of these two modules to distinguish between diseased and healthy states with ML algorithms: KNN, SVM, and Random Forest. Furthermore, we performed drug repurposing analysis and text-mining analyses, employing the nodes of clusters as drug targets to identify novel drug candidates for ALS. The potential impact of the drug candidates on the expression of cluster genes was predicted using linear regression, SVR, Random Forest, Gradient Boosting, and neural network algorithms. As a result, we identified five novel drug candidates for the treatment of ALS: Nilotinib, Trovafloxacin, Apratoxin A, Carboplatin, and Clinafloxacin. These findings highlight the potential of drug repurposing in ALS treatment and suggest that further validation through experimental studies could lead to new therapeutic avenues.

β-synuclein in cerebrospinal fluid as a potential biomarker for distinguishing human prion diseases from Alzheimer's and Parkinson's disease

BACKGROUND

β-synuclein (β-syn), mainly expressed in central nerve system, is one of the biomarkers in cerebrospinal fluid (CSF) and blood for synaptic damage, which has been reported to be elevated in CSF and blood of the patients of prion diseases (PrDs).

METHODS

We analyzed 314 CSF samples from patients in China National Surveillance for CJD. The diagnostic groups of the 223 patients with PrDs included sporadic Creutzfeldt-Jacob disease (sCJD), genetic CJD (gCJD), fatal familial insomnia (FFI) and Gerstmann-Straussler-Scheinker (GSS). 91 patients with non-PrDs comprised Alzheimer's disease (AD), Parkinson's disease (PD), viral encephalitis (VE) or autoimmune encephalitis (AE) were enrolled in the control groups. The CSF β-syn levels were measured by a commercial microfluidic ELISA. The Mann-Whitney U test and Kruskal-Wallis H test were employed to analyze two or more sets of continuous variables. Multiple linear regression was also performed to evaluate the factors for CSF β-syn levels. Receiver operating characteristics (ROC) curves and area under the curve (AUC) values were used to assess the diagnostic performance of β-syn.

RESULTS

The median of β-syn levels (2074 pg/ml; IQR: 691 to 4332) of all PrDs was significantly higher than that of non-PrDs group (504 pg/ml; IQR: 126 to 3374). The CSF β-syn values in the cohorts of sCJD, T188K-gCJD, E200K-gCJD and P102L-GSS were remarkably higher than that of the group of AD + PD, but similar as that of the group of VE + AE. The elevated CSF β-syn in sCJD and gCJD cases was statistically associated with CSF 14-3-3 positive and appearance of mutism. ROC curve analysis identified satisfied performance for distinguishing from AD + PD, with high AUC values in sCJD (0.7640), T188K-gCJD (0.8489), E200K-gCJD (0.8548), P102L-GSS (0.7689) and D178N-FFI (0.7210), respectively.

CONCLUSION

Our data here indicate that CSF β-syn is a potential biomarker for distinguishing PrDs (gCJD, sCJD and GSS) from AD and PD, but is much less efficient from VE and AE. These findings have critical implications for early diagnosis and monitoring of synaptic integrity in prion diseases.

Clinical value of novel blood-based tau biomarkers in Creutzfeldt-Jakob disease

BACKGROUND

The diagnostic and prognostic performance of the novel fluid biomarkers brain-derived tau (BD-tau) and phospho-tau217 (p-tau217) in Creutzfeldt-Jakob disease (CJD) is not defined.

METHODS

We measured cerebrospinal fluid (CSF) and plasma BD-tau, p-tau217, p-tau181, total tau (t-tau), neurofilament light (NfL), and 14-3-3 in 100 CJD patients, 100 with non-prion rapidly progressive dementia (np-RPD), 92 with mild cognitive impairment due to Alzheimer's disease (AD-MCI), and 55 healthy controls (HC).

RESULTS

Plasma BD-tau performed comparably to plasma t-tau but had lower performance than CSF t-tau (p < 0.001) and 14-3-3 (p = 0.014) in CJD versus np-RPD differential diagnosis. Plasma BD-tau diagnostic accuracy increased when ratioed to plasma p-tau217, matching CSF 14-3-3. Plasma BD-tau levels were associated with survival (p < 0.001), outperforming t-tau and NfL.

DISCUSSION

Plasma BD-tau is a valuable marker for CJD prognostication. In the clinical setting, the plasma BD-tau/p-tau217 ratio provides an accurate, fast marker supporting the clinical diagnosis of CJD.

HIGHLIGHTS

The increase of plasma BD-tau levels parallels that of CSF t-tau in CJD. CSF p-tau217 levels are significantly increased in CJD, reflecting a prion-specific secondary tauopathy. Plasma p-tau217 shows a distinct profile than CSF p-tau217 in CJD. Plasma BD-tau/p-tau217 ratio is as accurate as CSF 14-3-3 in distinguishing CJD from np-RPDs, including AD. BD-tau represents a valuable blood-based biomarker for CJD prognostication.

Prognostic serum biomarkers of synaptic, neuronal and glial injury in patients with acute ischemic stroke of the anterior circulation

BACKGROUND

We aimed to investigate the prognostic role of β-synuclein in comparison to that of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) for predicting functional outcome after acute ischemic stroke (AIS).

METHODS

We measured serum concentrations of β-synuclein, NfL and GFAP 24 h after hospital admission in 213 consecutive patients with moderate-to-severe AIS. We investigated the association between serum biomarkers and radiological/clinical characteristics, 3-months mortality and functional outcome on the modified Rankin Scale (mRS).

RESULTS

In 213 patients with AIS [mean age: 76.1 (±12.5) years, 53.1% males, median NIHSS score on admission: 13 (IQR: 9-17)], higher levels of β-synuclein, NfL and GFAP were associated with higher NIHSS scores and with lower Alberta Stroke Program CT Score (ASPECTS) points on admission. Serum β-synuclein levels was significantly correlated with NfL (rho = 0.715, p < 0.001) and GFAP concentrations (rho = 0.684, p < 0.001). The inclusion of serum β-synuclein significantly improved the accuracy of prediction models without biomarkers for overall mortality (AUC: 0.836 vs. 0.752, p < 0.001) and mRS 3-6 vs. 0-2 (AUC: 0.812 vs. 0.624, p < 0.001). Combination models with NfL and/or GFAP showed a similar accuracy.

CONCLUSIONS

Serum β-synuclein may be used to assess synaptic damage/dysfunction and to predict 3-months clinical outcomes in patients with AIS.

Serum growth differentiation factor-15, glial fibrillary acidic protein, and neurofilament light chain: Their link and role in Creutzfeldt-Jakob disease

BACKGROUND

Creutzfeldt-Jakob disease (CJD) is a rapidly progressive neurodegenerative disorder characterized by neuronal damage. Emerging biomarkers, such as serum neurofilament light chain (sNfL), glial fibrillary acidic protein (sGFAP), and growth differentiation factor-15 (sGDF-15), are currently being studied for their potential use in this disease.

OBJECTIVES

This study analyzes the levels of sNfL, sGFAP, and sGDF-15, as well as their relationships, in patients with CJD compared to healthy controls (HC).

METHODS

A total of 19 CJD patients and 81 age- and sex-matched HCs were enrolled. Serum levels of sNfL and sGFAP were measured using ultrasensitive immunoassays, while sGDF-15 levels were assessed via ELISA. Statistical analyses included correlation analysis and analysis of covariance (ANCOVA) models.

RESULTS

CJD patients showed significantly higher serum levels of sNfL and sGFAP compared to HCs (p <0,001). sNfL levels were positively correlated with both sGFAP (Rho = 0,70; p < 0,001) and sGDF-15 (Rho = 0,60; p = 0,004). Interestingly, sGFAP levels were higher in female CJD patients compared to males (p = 0,001), while no significant difference in sNfL levels was observed between sexes.

CONCLUSIONS

In conclusion, this study explores the potential of sNfL, sGDF-15, and sGFAP as biomarkers in CJD patients. The higher levels of sNfL and sGFAP in CJD patients compared to healthy controls, along with the observed sex differences in sGFAP, highlight the need for further research into the interaction between astroglia and neurons in CJD, with a focus on sex as a key variable.

FDG-PET patterns associate with survival in patients with prion disease

OBJECTIVE

Prion disease classically presents with rapidly progressive dementia, leading to death within months of diagnosis. Advances in diagnostic testing have improved recognition of patients with atypical presentations and protracted disease courses, raising key questions surrounding the relationship between patterns of neurodegeneration and survival. We assessed the contribution of fluorodeoxyglucose (FDG-PET) imaging for this purpose.

METHODS

FDG-PET were performed in 40 clinic patients with prion disease. FDG-PET images were projected onto latent factors generated in an external dataset to yield patient-specific eigenvalues. Eigenvalues were input into a clustering algorithm to generate data-driven clusters, which were compared by survival time.

RESULTS

Median age at FDG-PET was 65.3 years (range 23-85). Median time from FDG-PET to death was 3.7 months (range 0.3-19.0). Four data-driven clusters were generated, termed "Neocortical" (n = 7), "Transitional" (n = 12), "Temporo-parietal" (n = 13), and "Deep nuclei" (n = 6). Deep nuclei and transitional clusters had a shorter survival time than the neocortical cluster. Subsequent analyses suggested that this difference was driven by greater hypometabolism of deep nuclei relative to neocortical areas. FDG-PET-patterns were not associated with demographic (age and sex) or clinical (CSF total-tau, 14-3-3) variables.

INTERPRETATION

Greater hypometabolism within deep nuclei relative to neocortical areas associated with more rapid decline in patients with prion disease and vice versa. FDG-PET informs large-scale network physiology and may inform the relationship between spreading pathology and survival in patients with prion disease. Future studies should consider whether FDG-PET may enrich multimodal prion disease prognostication models.

Neurofilaments as biomarkers in neurological disorders - towards clinical application

Neurofilament proteins have been validated as specific body fluid biomarkers of neuro-axonal injury. The advent of highly sensitive analytical platforms that enable reliable quantification of neurofilaments in blood samples and simplify longitudinal follow-up has paved the way for the development of neurofilaments as a biomarker in clinical practice. Potential applications include assessment of disease activity, monitoring of treatment responses, and determining prognosis in many acute and chronic neurological disorders as well as their use as an outcome measure in trials of novel therapies. Progress has now moved the measurement of neurofilaments to the doorstep of routine clinical practice for the evaluation of individuals. In this Review, we first outline current knowledge on the structure and function of neurofilaments. We then discuss analytical and statistical approaches and challenges in determining neurofilament levels in different clinical contexts and assess the implications of neurofilament light chain (NfL) levels in normal ageing and the confounding factors that need to be considered when interpreting NfL measures. In addition, we summarize the current value and potential clinical applications of neurofilaments as a biomarker of neuro-axonal damage in a range of neurological disorders, including multiple sclerosis, Alzheimer disease, frontotemporal dementia, amyotrophic lateral sclerosis, stroke and cerebrovascular disease, traumatic brain injury, and Parkinson disease. We also consider the steps needed to complete the translation of neurofilaments from the laboratory to the management of neurological diseases in clinical practice.

Serum β-synuclein, neurofilament light chain and glial fibrillary acidic protein as prognostic biomarkers in moderate-to-severe acute ischemic stroke

We aimed to assess the prognostic value of serum β-synuclein (β-syn), neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in patients with moderate-to-severe acute ischemic stroke. We measured β-syn, GFAP and NfL in serum samples collected one day after admission in 30 adult patients with moderate-to-severe ischemic stroke due to middle cerebral artery (MCA) occlusion. We tested the associations between biomarker levels and clinical and radiological scores (National Institute of Health Stroke Scale scores, NIHSS, and Alberta Stroke Program Early CT Score, ASPECTS), as well as measures of functional outcome (modified Rankin Scale, mRS). Serum biomarkers were significantly associated with ASPECTS values (β-syn p = 0.0011, GFAP p = 0.0002) but not with NIHSS scores at admission. Patients who received mechanical thrombectomy and intravenous thrombolysis showed lower β-syn (p = 0.029) und NfL concentrations (p = 0.0024) compared to patients who received only mechanical thrombectomy. According to median biomarker levels, patients with high β-syn, NfL or GFAP levels showed, after therapy, lower clinical improvement (i.e., lower 24-h NIHSS change), higher NIHSS scores during hospitalization and higher mRS scores at 3-month follow-up. Elevated serum concentrations of β-syn (p = 0.016), NfL (p = 0.020) or GFAP (p = 0.010) were significantly associated with 3-month mRS of 3-6 vs. 0-2 even after accounting for age, sex and renal function. In patients with moderate-to-severe acute ischemic stroke, serum β-syn, NfL and GFAP levels associated with clinical and radiological scores at different timepoints and were able to predict short- and middle-term clinical outcomes.

Plasma β-synuclein, GFAP, and neurofilaments in patients with malignant gliomas undergoing surgical and adjuvant therapy

We analyzed the longitudinal concentrations and prognostic roles of plasma β-synuclein (β-syn), glial fibrillary acidic protein (GFAP), and neurofilament proteins (NfL and NfH) in 33 patients with malignant gliomas, who underwent surgical and adjuvant therapy. GFAP and NfL levels were increased in patients with glioblastoma compared to cases with other tumors. β-syn, NfL and NfH increased after surgery, whereas GFAP decreased at long-term follow-up. β-syn and neurofilament concentrations were influenced by surgery and/or radiotherapy regimens. GFAP and neurofilament levels were significantly associated with survival. Plasma neuronal and astrocytic biomarkers are differentially altered in malignant glioma types and displayed distinct trajectories after surgical and adjuvant therapy.

High diagnostic performance of plasma and cerebrospinal fluid beta-synuclein for sporadic Creutzfeldt-Jakob disease

Beta-synuclein is a promising cerebrospinal fluid and blood biomarker of synaptic damage. Here we analysed its accuracy in the discrimination between sporadic Creutzfeldt-Jakob disease (n = 150) and non-prion rapidly progressive dementias (n = 106). In cerebrospinal fluid, beta-synuclein performed better than protein 14-3-3 (AUC 0.95 vs. 0.89) and, to a lesser extent, than total tau (AUC 0.92). Further, the diagnostic value of plasma beta-synuclein (AUC 0.91) outperformed that of plasma tau (AUC 0.79) and neurofilament light chain protein (AUC 0.65) and was comparable to that of cerebrospinal fluid biomarkers. Beta-synuclein might represent the first highly accurate blood biomarker for the diagnosis of sporadic Creutzfeldt-Jakob disease.

Synucleinopathies: Intrinsic and Extrinsic Factors

α-Synucleinopathies are a group of neurodegenerative disorders characterized by alterations in α-synuclein (α-syn), a protein associated with membrane phospholipids, whose precise function in normal cells is still unknown. These kinds of diseases are caused by multiple factors, but the regulation of the α-syn gene is believed to play a central role in the pathology of these disorders; therefore, the α-syn gene is one of the most studied genes. α-Synucleinopathies are complex disorders that derive from the interaction between genetic and environmental factors. Here, we offer an update on the landscape of the epigenetic regulation of α-syn gene expression that has been linked with α-synucleinopathies. We also delve into the reciprocal influence between epigenetic modifications and other factors related to these disorders, such as posttranslational modifications, microbiota participation, interactions with lipids, neuroinflammation and oxidative stress, to promote α-syn aggregation by acting on the transcription and/or translation of the α-syn gene.

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.

Validity of CSF alpha-synuclein to predict psychosis in prodromal Alzheimer's disease

Background

Alzheimer's disease (AD) accompanied by psychotic symptoms (PS) has a poor prognosis and may be associated with imbalances in key neural proteins such as alpha-synuclein (AS).

Aim

The aim of the study was to evaluate the diagnostic validity of AS levels in the cerebrospinal fluid (CSF) as a predictor of the emergence of PS in patients with prodromal AD.

Materials and methods

Patients with mild cognitive impairment were recruited between 2010 and 2018. Core AD biomarkers and AS levels were measured in CSF obtained during the prodromal phase of the illness. All patients who met the NIA-AA 2018 criteria for AD biomarkers received treatment with anticholinesterasic drugs. Follow-up evaluations were conducted to assess patients for the presence of psychosis using current criteria; the use of neuroleptic drugs was required for inclusion in the psychosis group. Several comparisons were made, taking into account the timing of the emergence of PS.

Results

A total of 130 patients with prodromal AD were included in this study. Of these, 50 (38.4%) met the criteria for PS within an 8-year follow-up period. AS was found to be a valuable CSF biomarker to differentiate between the psychotic and non-psychotic groups in every comparison made, depending on the onset of PS. Using an AS level of 1,257 pg/mL as the cutoff, this predictor achieved at least 80% sensitivity.

Conclusion

To our knowledge, this study represents the first time that a CSF biomarker has shown diagnostic validity for prediction of the emergence of PS in patients with prodromal AD.

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.

The Underestimated Relevance of Alzheimer's Disease Copathology in Amyotrophic Lateral Sclerosis

Concomitant Alzheimer's disease (AD) pathology can be observed in approximately 10-15% of cases with amyotrophic lateral sclerosis (ALS). ALS-AD patients have a higher prevalence of amnestic cognitive disturbances, which may often precede motor symptoms. Cerebrospinal fluid (CSF) AD core biomarkers usually show no or slightly significant changes in ALS, whereas blood phosphorylated tau protein might be increased independently from AD copathology. Neurofilament proteins are consistently elevated in CSF and blood of ALS, but have been poorly investigated in ALS-AD. All these issues should be taken into account when using fluid biomarkers as inclusion criteria or secondary endpoints in clinical trials.

β-Synuclein as a candidate blood biomarker for synaptic degeneration in Alzheimer's disease

Synaptic degeneration is an early event closely associated with the course of Alzheimer's disease (AD). The identification of synaptic blood biomarkers is, therefore, of great interest and clinical relevance. The levels of most synaptic proteins are increased in the cerebrospinal fluid (CSF) of patients with AD, but their detection in blood is hitherto either unavailable or not very informative. This paradigm is related to their low concentration, their peripheral origin, or the presence of highly abundant blood proteins that hinder detection. In recent years, significant progress has been made in detecting the presynaptic protein β-synuclein. This mini-review summarizes the results that highlight the role of β-synuclein as a candidate blood marker for synaptic degeneration in AD.

Neurochemical Monitoring of Traumatic Brain Injury by the Combined Analysis of Plasma Beta-Synuclein, NfL, and GFAP in Polytraumatized Patients

Traumatic brain injury (TBI) represents a major determining factor of outcome in severely injured patients. However, reliable brain-damage-monitoring markers are still missing. We therefore assessed brain-specific beta-synuclein as a novel blood biomarker of synaptic damage and measured the benchmarks neurofilament light chain (NfL), as a neuroaxonal injury marker, and glial fibrillary acidic protein (GFAP), as an astroglial injury marker, in patients after polytrauma with and without TBI. Compared to healthy volunteers, plasma NfL, beta-synuclein, and GFAP were significantly increased after polytrauma. The markers demonstrated highly distinct time courses, with beta-synuclein and GFAP peaking early and NfL concentrations gradually elevating during the 10-day observation period. Correlation analyses revealed a distinct influence of the extent of extracranial hemorrhage and the severity of head injury on biomarker concentrations. A combined analysis of beta-synuclein and GFAP effectively discriminated between polytrauma patients with and without TBI, despite the comparable severity of injury. Furthermore, we found a good predictive performance for fatal outcome by employing the initial plasma concentrations of NfL, beta-synuclein, and GFAP. Our findings suggest a high diagnostic value of neuronal injury markers reflecting distinct aspects of neuronal injury for the diagnosis of TBI in the complex setting of polytrauma, especially in clinical surroundings with limited imaging opportunities.