NfL (Neurofilament Light Chain) Levels as a Predictive Marker for Long-Term Outcome After Ischemic Stroke

Serum neurofilament light chain: a predictive marker for outcomes following mild-to-moderate ischemic stroke

Background

Biomarkers that reflect brain damage or predict functional outcomes may aid in guiding personalized stroke treatments. Serum neurofilament light chain (sNfL) emerges as a promising candidate for fulfilling this role.

Methods

This prospective, observational cohort investigation included 319 acute ischemic stroke (IS) patients. The endpoints were the incidence of early neurological deterioration (END, an elevation of two or more points in the National Institute of Health stroke scale score within a week of hospitalization compared with the baseline) and functional outcome at 3 months (an mRS score of >2 at 3 months was categorized as an unfavorable/poor functional outcome). The association of sNfL, which was assessed within 24 h of admission, with END and unfavorable functional outcomes at follow-up was assessed via multivariate logistic regression, whereas the predictive value of sNfL for unfavorable functional outcomes and END was elucidated by the receiver operating characteristic curve (ROC).

Results

Of 319 IS individuals, 89 (27.90%) suffered from END. sNfL not only reflects the severity of stroke measured by NIHSS score (p < 0.05) but also closely related to the severity of age-related white matter changes. Higher initial NIHSS score, severe white matter lesions, diabetes mellitus, and upregulated sNfL were significant predictors of END. Similarly, the multivariate logistic regression analysis results showed that elevated sNfL, a higher baseline NIHSS score, and severe white matter lesions were substantially linked with unfavorable outcomes for 3 months. Similarly, sNfL was valuable for the prediction of the 3 months of poor outcome (95%CI, 0.504-0.642, p = 0.044). Kaplan-Meier analysis shows that patients with elevated sNfL levels are more likely to reach combined cerebrovascular endpoints (log-rank test p < 0.05).

Conclusion

This investigation suggests that sNfL can serve as a valuable biomarker for predicting END and 3-month poor functional outcomes after an IS and has the potential to forecast long-term cardiovascular outcomes.

Serum neurofilament light chain as a prognostic marker of all-cause mortality in a national sample of US adults

Neurofilament light chain (NfL) is a neuron-specific structural protein released into the extracellular space, including body fluids, upon neuroaxonal damage. Despite evidence of a link in neurological disorders, few studies have examined the association of serum NfL with mortality in population-based studies. Data from the National Health and Nutrition Survey were utilized including 2,071 Non-Hispanic White, Non-Hispanic Black and Hispanic adult participants and adult participants of other ethnic groups (20-85 years) with serum NfL measurements who were followed for ≤ 6 years till 2019. We tested the association of serum NfL with mortality in the overall population and stratified by sex with the addition of potential interactive and mediating effects of cardio-metabolic risk factors and nutritional biomarkers. Elevated serum NfL levels (above median group) were associated with mortality risk compared to the below median NfL group in the overall sample (P = 0.010), with trends observed within each sex group (P < 0.10). When examining Loge NfL as a continuum, one standard deviation of Loge NfL was associated with an increased mortality risk (HR = 1.88, 95% CI 1.60-2.20, P < 0.001) in the reduced model adjusted for age, sex, race, and poverty income ratio; a finding only slightly attenuated with the adjustment of lifestyle and health-related factors. Four-way decomposition indicated that there was, among others, mediated interaction between NfL and HbA1c and a pure inconsistent mediation with 25(OH)D3 in predicting all-cause mortality, in models adjusted for all other covariates. Furthermore, urinary albumin-to-creatinine ratio interacted synergistically with NfL in relation to mortality risk both on the additive and multiplicative scales. These data indicate that elevated serum NfL levels were associated with all-cause mortality in a nationally representative sample of US adults.

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.

Association of Plasma Brain-Derived Tau With Functional Outcome After Ischemic Stroke

OBJECTIVES

To investigate whether circulating acute-phase brain-derived tau (BD-tau) is associated with functional outcome after ischemic stroke.

METHODS

Plasma tau was measured by a novel assay that selectively quantifies BD-tau in the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS), which includes adult cases with ischemic stroke and controls younger than 70 years, and in an independent cohort of adult cases of all ages (SAHLSIS2). Associations with unfavorable 3-month functional outcome (modified Rankin scale score >2) were analyzed by logistic regression. Various stratified and sensitivity analyses were performed, for example, by age, stroke severity, recanalization therapy, and etiologic subtype.

RESULTS

This study included 454 and 364 cases from the SAHLSIS and SAHLSIS2, with a median age of 58 and 68 years, respectively. Higher acute BD-tau concentrations were significantly associated with increased odds of unfavorable outcome after adjustment for age, sex, day of blood draw, and stroke severity (NIH stroke scale score) in both cohorts (OR per doubling of BD-tau: 2.9 [95% CI 2.2-3.7], P = 1 × 10-15 and 1.8 [1.5-2.2], P = 7 × 10-9, respectively). The association was consistent in the different stratified and sensitivity analyses.

DISCUSSION

BD-tau is a promising blood-based biomarker of ischemic stroke outcomes, and future studies in larger cohorts are warranted.

Incremental value of serum neurofilament light chain and glial fibrillary acidic protein as blood-based biomarkers for predicting functional outcome in severe acute ischemic stroke

INTRODUCTION

Blood-based biomarkers may improve prediction of functional outcome in patients with acute ischemic stroke. The role of neurofilament light chain (NfL) and glial fibrillary acidic (GFAP) as potential biomarkers especially in severe stroke patients is unknown.

PATIENTS AND METHODS

Prospective, monocenter, cohort study including consecutive patients with severe ischemic stroke in the anterior circulation on admission (NIHSS score ⩾ 6 points or indication for mechanical thrombectomy). Outcome was assessed 3 months after the index stroke by the modified Rankin Scale (mRS). Serum biomarkers levels of NfL and GFAP were determined by ultrasensitive ELISA. Univariate and multivariate logistic regression models were performed to determine the association of biomarker levels and functional disability. Discrimination, calibration, and overall performance were analyzed in different models via AUROC, calibration plots (with Emax and Eavg), Brier-score and R2 using variables, identified as important covariates for functional outcome in previous studies.

RESULTS

Between 06/2020 and 08/2021, 213 patients were included [47% female, mean age 76 (SD ± 12) years, median NIHSS score 13 (interquartile range, IQR 9; 17)]. Biomarker serum levels were measured at a median of 1 [IQR, 1; 2] day after admission. Compared to patients with mRS 0-2 at 3 months, patients with mRS 3-6 had higher serum levels of NfL (median: 136 pg/ml vs 41 pg/ml; p < 0.0001) and GFAP (700 ng/ml vs 9.6 ng/ml; p < 0.0001). Both biomarkers were significantly associated with functional outcome [adjusted logistic regression, odds ratio (95% CI) for NfL: 2.63 (1.62; 4.56), GFAP: 2.16 (1.58; 3.09)]. In all models the addition of serum NfL led to a significant improvement in the AUROC, as did the addition of serum GFAP. Calibration plots showed high agreement between the predicted and observed outcomes and after addition of the two blood-based biomarkers there was an improvement of the overall performance.

CONCLUSION

Prediction of functional outcome after severe acute ischemic stroke was improved by the blood-based biomarkers serum NfL and GFAP, measured in the acute phase of stroke. These findings have to be replicated in independent external cohorts.Study registration: DRKS00022064.

Fluid biomarkers of the neurovascular unit in cerebrovascular disease and vascular cognitive disorders: A systematic review and meta-analysis

Background

The disruption of the neurovascular unit (NVU), which maintains the integrity of the blood brain barrier (BBB), has been identified as a critical mechanism in the development of cerebrovascular and neurodegenerative disorders. However, the understanding of the pathophysiological mechanisms linking NVU dysfunction to the disorders is incomplete, and reliable blood biomarkers to measure NVU dysfunction are yet to be established. This systematic review and meta-analysis aimed to identify biomarkers associated with BBB dysfunction in large vessel disease, small vessel disease (SVD) and vascular cognitive disorders (VCD).

Methods

A literature search was conducted in PubMed, EMBASE, Scopus and PsychINFO to identify blood biomarkers related to dysfunction of the NVU in disorders with vascular pathologies published until 20 November 2023. Studies that assayed one or more specific markers in human serum or plasma were included. Quality of studies was assessed using the Newcastle-Ottawa Quality Assessment Scale. Effects were pooled and methodological heterogeneity examined using the random effects model.

Results

A total of 112 studies were included in this review. Where study numbers allowed, biomarkers were analysed using random effect meta-analysis for VCD (1 biomarker; 5 studies) and cerebrovascular disorders, including stroke and SVD (9 biomarkers; 29 studies) while all remaining biomarkers (n = 17 biomarkers; 78 studies) were examined through qualitative analysis. Results of the meta-analysis revealed that cerebrospinal fluid/serum albumin quotient (Q-Alb) reliably differentiates VCD patients from healthy controls (MD = 2.77; 95 % CI = 1.97-3.57; p < 0.0001) while commonly measured biomarkers of endothelial dysfunction (VEGF, VCAM-1, ICAM-1, vWF and E-selectin) and neuronal injury (NfL) were significantly elevated in vascular pathologies. A qualitative assessment of non-meta-analysed biomarkers revealed NSE, NfL, vWF, ICAM-1, VCAM-1, lipocalin-2, MMP-2 and MMP-9 levels to be upregulated in VCD, although these findings were not consistently replicated.

Conclusions

This review identifies several promising biomarkers of NVU dysfunction which require further validation. A panel of biomarkers representing multiple pathophysiological pathways may offer greater discriminative power in distinguishing possible disease mechanisms of VCD.

Delirium pathophysiology in cancer: neurofilament light chain biomarker - narrative review

Background Delirium is a debilitating disorder with high prevalence near the end of life, impacting quality of life of patients and their relatives. Timely recognition of delirium can lead to prevention and/or better treatment of delirium. According to current hypotheses delirium is thought to result from aberrant inflammation and neurotransmission, with a possible role for neuronal damage. Neurofilament light chain (NfL) is a protein biomarker in body fluids that is unique to neurons, with elevated levels when neurons are damaged, making NfL a viable biomarker for early detection of delirium. This narrative review summarises current research regarding the pathophysiology of delirium and the potential of NfL as a susceptibility biomarker for delirium and places this in the context of care for patients with advanced cancer.Results Six studies were conducted exclusively on NfL in patients with delirium. Three of these studies demonstrated that high plasma NfL levels preoperatively predict delirium in older adult patients postoperatively. Two studies demonstrated that high levels of NfL in intensive care unit (ICU) patients are correlated with delirium duration and severity. One study found that incident delirium in older adult patients was associated with increased median NfL levels during hospitalisation.Conclusions Targeted studies are required to understand if NfL is a susceptibility biomarker for delirium in patients with advanced cancer. In this palliative care context, better accessible matrices, such as saliva or urine, would be helpful for repetitive testing. Improvement of biological measures for delirium can lead to improved early recognition and lay the groundwork for novel therapeutic strategies.

Strict blood pressure control following thrombectomy is associated with neuronal injury and poor functional outcome

OBJECTIVE

Mechanical thrombectomy (MT) has become standard treatment in acute ischemic stroke due to large vessel occlusion (LVO). However, optimal blood pressure (BP) management following successful recanalization remains unclear. We aim to investigate the association of strictly achieving BP targets of ≤160/90 mmHg with the extent of neuronal loss and functional outcome.

METHODS

In patients prospectively enrolled in the Gutenberg-Stroke-Study (May 2018-November 2019), BP was measured half-hourly for 24 h following MT. Based on achieving BP target of ≤160/90 mmHg, patients with successful recanalization of LVO were divided into "low-BP" group (BP ≤ 160/90 mmHg) or "high-BP" group (BP > 160/90 mmHg). Neuronal loss was quantified by serum-based measurement of neurofilament light chain (sNfL) after three days. BP groups and association of BP parameters with sNfL were investigated by correlation analyses and multiple regression modeling.

RESULTS

Of 253 enrolled patients (mean age 73.1 ± 12.9 years, 53.4% female), 165 met inclusion criteria. 21.2% (n = 35) strictly achieved "low-BP" target. "low-BP" was associated with unfavorable functional outcome at 90-day follow-up (aOR [95%CI]: 5.88 [1.88-18.32], p = 0.002) and decreased health-related quality of life (mean EQ-5D-index 0.45 ± 0.28 vs 0.63 ± 0.31, p = 0.009). sNfL levels were increased in "low-BP" patients (median [IQR] 239.7 [168.4-303.4] vs 118.8 [52.5-220.5] pg/mL, p = 0.026). Hypotensive episodes were more frequent in the "low-BP" group (48.6% vs 29.2%, p = 0.031). sNfL level could identify patients who had experienced hypotensive episodes with high discriminative ability (AUC [95%CI]: 0.68 [0.56-0.78], p = 0.007).

INTERPRETATION

Strict BP control (≤160/90 mmHg) within 24 h following successful recanalization of LVO by MT is associated with increased neuronal injury, displayed by higher sNfL levels, and poorer functional outcome, potentially indicating hypotension-induced neuronal loss during post-MT phase.

Serum and cerebrospinal fluid brain damage markers neurofilament light and glial fibrillary acidic protein correlate with tick-borne encephalitis disease severity-a multicentre study on Lithuanian and Swedish patients

BACKGROUND AND PURPOSE

Our aim was to examine the correlation between biomarkers of neuronal and glial cell damage and severity of disease in patients with tick-borne encephalitis.

METHODS

One hundred and fifteen patients with tick-borne encephalitis diagnosed in Lithuania and Sweden were prospectively included, and cerebrospinal fluid (CSF) and serum samples were obtained shortly after hospitalization. Using pre-defined criteria, cases were classified as mild, moderate or severe tick-borne encephalitis. Additionally, the presence of spinal nerve paralysis (myelitis) and/or cranial nerve affection were noted. Concentrations of the brain cell biomarkers glial fibrillary acidic protein (GFAP), YKL-40, S100B, neurogranin, neurofilament light (NfL) and tau were analysed in CSF and, in addition, NfL, GFAP and S100B levels were measured in serum. The Jonckheere-Terpstra test was used for group comparisons of continuous variables and Spearman's partial correlation test was used to adjust for age.

RESULTS

Cerebrospinal fluid and serum concentrations of GFAP and NfL correlated with disease severity, independent of age, and with the presence of nerve paralysis. The markers neurogranin, YKL-40, tau and S100B in CSF and S100B in serum were detected, but their concentrations did not correlate with disease severity.

CONCLUSIONS

Neuronal cell damage and astroglial cell activation with increased NfL and GFAP in CSF and serum were associated with a more severe disease, independent of age. Increased GFAP and NfL concentrations in CSF and NfL in serum were also indicative of spinal and/or cranial nerve damage. NfL and GFAP are promising prognostic biomarkers in tick-borne encephalitis, and future studies should focus on determining the association between these biomarkers and long-term sequelae.

Plasma neurofilament light and brain volumetric outcomes among middle-aged urban adults

Elevated plasma neurofilament light chain (NfL) is associated with dementia though underlying mechanisms remain unknown. We examined cross-sectional relationships of time-dependent plasma NfL with selected brain structural magnetic resonance imaging (sMRI) prognostic markers of dementia. The sample was drawn from the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study, selecting participants with complete v1 (2004-2009) and v2 (2009-2013) plasma NfL exposure and ancillary sMRI data at vscan (2011-2015, n = 179, mean v1 to vscan time: 5.4 years). Multivariable-adjusted linear regression models were conducted, overall, by sex, and race, correcting for multiple testing with q-values. NfL(v1) was associated with larger WMLV (both Loge transformed), after 5-6 years' follow-up, overall (β = +2.131 ± 0.660, b = +0.29, p = 0.001, and q = 0.0029) and among females. NfLv2 was linked to a 125 mm3 lower left hippocampal volume (p = 0.004 and q = 0.015) in reduced models, mainly among males, as was observed for annualized longitudinal change in NfL (δNfLbayes). Among African American adults, NfLv1 was inversely related to total, gray and white matter volumes. Plasma NfL may reflect future brain pathologies in middle-aged adults.

Quantification and prospective evaluation of serum NfL and GFAP as blood-derived biomarkers of outcome in acute ischemic stroke patients

Identification of reliable and accessible biomarkers to characterize ischemic stroke patients' prognosis remains a clinical challenge. Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) are markers of brain injury, detectable in blood by high-sensitive technologies. Our aim was to measure serum NfL and GFAP after stroke, and to evaluate their correlation with functional outcome and the scores in rehabilitation scales at 3-month follow-up. Stroke patients were prospectively enrolled in a longitudinal observational study within 24 hours from symptom onset (D1) and monitored after 7 (D7), 30 ± 3 (M1) and 90 ± 5 (M3) days. At each time-point serum NfL and GFAP levels were measured by Single Molecule Array and correlated with National Institute of Health Stroke Scale (NIHSS), modified Rankin scale (mRS), Trunk Control Test (TCT), Functional Ambulation Classification (FAC) and Functional Independence Measure (FIM) scores. Serum NfL and GFAP showed different temporal profiles: NfL increased after stroke with a peak value at D7; GFAP showed an earlier peak at D1. NfL and GFAP concentrations correlated with clinical/rehabilitation outcomes both longitudinally and prospectively. Multivariate analysis revealed that NfL-D7 and GFAP-D1 were independent predictors of 3-month NIHSS, TCT, FAC and FIM scores, with NfL being the biomarker with the best predictive performance.

Secondary neurodegeneration following Stroke: what can blood biomarkers tell us?

Stroke is one of the leading causes of death and the primary source of disability in adults, resulting in neuronal necrosis of ischemic areas, and in possible secondary degeneration of regions surrounding or distant to the initial damaged area. Secondary neurodegeneration (SNDG) following stroke has been shown to have different pathogenetic origins including inflammation, neurovascular response and cytotoxicity, but can be associated also to regenerative processes. Aside from focal neuronal loss, ipsilateral and contralateral effects distal to the lesion site, disruptions of global functional connectivity and a transcallosal diaschisis have been reported in the chronic stages after stroke. Furthermore, SNDG can be observed in different areas not directly connected to the primary lesion, such as thalamus, hippocampus, amygdala, substantia nigra, corpus callosum, bilateral inferior fronto-occipital fasciculus and superior longitudinal fasciculus, which can be highlighted by neuroimaging techniques. Although the clinical relevance of SNDG following stroke has not been well understood, the identification of specific biomarkers that reflect the brain response to the damage, is of paramount importance to investigate in vivo the different phases of stroke. Actually, brain-derived markers, particularly neurofilament light chain, tau protein, S100b, in post-stroke patients have yielded promising results. This review focuses on cerebral morphological modifications occurring after a stroke, on associated cellular and molecular changes and on state-of-the-art of biomarkers in acute and chronic phase. Finally, we discuss new perspectives regarding the implementation of blood-based biomarkers in clinical practice to improve the rehabilitation approaches and post stroke recovery.

Increased plasma levels of circPTP4A2 and circTLK2 are associated with stroke injury

OBJECTIVE

Accumulating studies have shown that circulating circular RNAs (circRNAs) represent novel biomarkers for many human diseases. We investigated whether plasma circPTP4A2 and circTLK2 levels are associated with stroke severity, infarct volume, stroke etiology, and functional outcome in acute ischemic stroke (AIS) patients.

METHODS

We applied quantitative real-time PCR (qPCR) to measure plasma circPTP4A2 and circTLK2 levels of 236 AIS patients within 72 h of symptoms onset and 136 healthy controls. We further assessed the National Institutes of Health Stroke Scale (NIHSS), infarct size, the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification and the 90-day modified Rankin scale (mRS) for each patient.

RESULTS

At admission, plasma circPTP4A2 and circTLK2 levels in patients with moderate to severe stroke were significantly higher compared to those with mild stroke. Logistic regression and receiver-operating characteristic (ROC) curve analyses indicated that they might function as predictive biomarkers for moderate to severe stroke. We also observed a medium positive correlation between these two circRNAs and NIHSS. Plasma circPTP4A2 and circTLK2 levels were slight positively correlated with cerebral infarct volume only in anterior circulation infarction (ACI) patients. Levels of both circPTP4A2 and circTLK2 were closely related with large artery atherosclerosis (LAA) stroke. Moreover, changes within 7 days after admission in circPTP4A2 and circTLK2 were able to predict unfavorable clinical outcome 90 days after AIS.

INTERPRETATION

These results demonstrate that plasma circPTP4A2 and circTLK2 strongly correlated with severity, subtypes and prognosis of AIS, and they could serve as promising biomarkers.

Growth differentiation factor 15 predicts cardiovascular events in stable coronary artery disease

BACKGROUND

Growth differentiation factor 15 (GDF-15) has been explored as a potential biomarker for various inflammatory diseases and cardiovascular events. This study aimed to assess the predictive role of GDF-15 levels in cardiovascular events and all-cause mortality, considering traditional risk factors and other biomarkers.

METHODS

A prospective study was conducted and 3699 patients with stable coronary artery disease (CAD) were enrolled into the research. Baseline GDF-15 levels were measured. Median follow-up was 3.1 years during the study. We analyzed clinical variables and several biomarkers. Multivariable Cox regression analysis was performed to evaluate prognostic performance of GDF-15 levels in predicting myocardial infarction (MI), heart failure, stroke, cardiovascular death, and non-cardiovascular death.

RESULTS

Baseline GDF-15 levels for 3699 patients were grouped by quartile (≤ 1153, 1153-1888, 1888-3043, > 3043 ng/L). Higher GDF-15 levels were associated with older age, male gender, history of hypertension, and elevated levels of N-terminal pro B-type natriuretic peptide (NT-pro BNP), soluble suppression of tumorigenesis-2 (sST2), and creatine (each with P < 0.001). Adjusting for established risk factors and biomarkers in Cox proportional hazards models, a 1 standard deviation (SD) increase in GDF-15 was associated with elevated risk of clinical events [hazard ratio (HR) = 2.18, 95% confidence interval (CI): (1.52-3.11)], including: MI [HR = 2.83 95% CI: (1.03-7.74)], heart failure [HR = 2.71 95% CI: (1.18-6.23)], cardiovascular and non-cardiovascular death [HR = 2.48, 95% CI (1.49-4.11)] during the median follow up of 3.1 years.

CONCLUSIONS

Higher levels of GDF-15 consistently provides prognostic information for cardiovascular events and all cause death, independent of clinical risk factors and other biomarkers. GDF-15 could be considered as a valuable addition to future risk prediction model in secondary prevention for predicting clinical events in patient with stable CAD.

Serum neurofilament light chain, brain infarcts, and the risk of stroke: a prospective population-based cohort study

Neurofilament light chain (NfL), a neuron-specific protein, has been related to several neurodegenerative diseases. In addition, elevated levels of NfL have also been observed in patients admitted to the hospital for stroke, suggesting that NfL as a biomarker may extend well beyond neurodegenerative diseases. Therefore, using data from the Chicago Health and Aging Project (CHAP), a population-based cohort study, we prospectively investigated the association of serum NfL levels with incident stroke and brain infarcts. During a follow-up of 3603 person-years, 133 (16.3%) individuals developed incident stroke, including ischemic and hemorrhagic. The HR (95%CI) of incident stroke was 1.28 (95%CI 1.10-1.50) per 1 standard deviation (SD) increase of log10 NfL serum levels. Compared to participants in the first tertile of NfL (i.e., lower levels), the risk of stroke was 1.68 times higher (95%CI 1.07-2.65) in those in the second tertile and 2.35 times higher (95%CI 1.45-3.81) in those in the third tertile of NfL. NfL levels were also positively associated with brain infarcts; 1-SD in log10 NfL levels was associated with 1.32 (95%CI 1.06-1.66) higher odds of one or more brain infarcts. These results suggest that NfL may serve as a biomarker of stroke in older adults.

Brain atrophy and white matter hyperintensities are independently associated with plasma neurofilament light chain in an Asian cohort of cognitively impaired patients with concomitant cerebral small vessel disease

Introduction

Plasma neurofilament light chain (NfL) is a potential biomarker for neurodegeneration in Alzheimer's disease (AD), ischemic stroke, and non‐dementia cohorts with cerebral small vessel disease (CSVD). However, studies of AD in populations with high prevalence of concomitant CSVD to evaluate associations of brain atrophy, CSVD, and amyloid beta (Aβ) burden on plasma NfL are lacking.

Methods

Associations were tested between plasma NfL and brain Aβ, medial temporal lobe atrophy (MTA) as well as neuroimaging features of CSVD, including white matter hyperintensities (WMH), lacunes, and cerebral microbleeds.

Results

We found that participants with either MTA (defined as MTA score ≥2; neurodegeneration [N]+WMH−) or WMH (cut‐off for log‐transformed WMH volume at 50th percentile; N−WMH+) manifested increased plasma NfL levels. Participants with both pathologies (N+WMH+) showed the highest NfL compared to N+WMH−, N−WMH+, and N−WMH− individuals.

Discussion

Plasma NfL has potential utility in stratifying individual and combined contributions of AD pathology and CSVD to cognitive impairment.

Serum neurofilament light chain levels are associated with early neurological deterioration in minor ischemic stroke

Objectives

Patients with minor ischemic stroke (MIS) frequently suffer from early neurological deterioration (END) and become disabled. Our study aimed to explore the association between serum neurofilament light chain (sNfL) levels and END in patients with MIS.

Methods

We conducted a prospective observational study in patients with MIS [defined as a National Institutes of Health Stroke Scale (NIHSS) score 0–3] admitted within 24 h from the onset of symptoms. sNfL levels were measured at admission. The primary outcome was END, defined as an increase in the NIHSS score by ≥2 points within 5 days after admission. Univariate and multivariate analyses were performed to explore the risk factors associated with END. Stratified analyses and interaction tests were conducted to identify variables that might modify the association between sNfL levels and END.

Results

A total of 152 patients with MIS were enrolled, of which 24 (15.8%) developed END. The median sNfL level was 63.1 [interquartile range (IQR), 51.2–83.4] pg/ml on admission, which was significantly higher than that of 40 age- and sex-matched healthy controls (median 47.6, IQR 40.8–56.1 pg/ml; p &lt; 0.001). Patients with MIS with END had a higher level of sNfL (with ND: median 74.1, IQR 59.5–89.8 pg/ml; without END: median 61.2, IQR 50.5–82.2 pg/ml; p = 0.026). After adjusting for age, baseline NIHSS score, and potential confounding factors in multivariate analyses, an elevated sNfL level (per 10 pg/mL) was associated with an increased risk of END [odds ratio (OR) 1.35, 95% confidence interval (CI) 1.04–1.77; p = 0.027). Stratified analyses and interaction tests demonstrated that the association between sNfL and END did not change by age group, sex, baseline NIHSS score, Fazekas' rating scale, hypertension, diabetes mellitus, intravenous thrombolysis, and dual antiplatelet therapy in patients with MIS (all p for interaction &gt; 0.05). END was associated with an increased risk of unfavorable outcomes (modified Rankin scale score ranging from 3 to 6) at 3 months.

Conclusion

Early neurological deterioration is common in minor ischemic stroke and is associated with poor prognosis. The elevated sNfL level was associated with an increased risk of early neurological deterioration in patients with minor ischemic stroke. sNfL might be a promising biomarker candidate that can help to identify patients with minor ischemic stroke at high risk of neurological deterioration, for reaching individual therapeutic decisions in clinical practice.

Rapid Activation of Neuroinflammation in Stroke: Plasma and Extracellular Vesicles Obtained on a Mobile Stroke Unit

BACKGROUND

Neuroinflammation is ubiquitous in acute stroke and worsens outcome. However, the precise timing of the inflammatory response is unknown, hindering the design of acute anti-inflammatory therapeutic interventions. We sought to identify the onset of the neuroinflammatory cascade using a mobile stroke unit.

METHODS

The study is a proof-of-concept, cohort investigation of ultra-early blood- and extracellular vesicle-derived markers of neuroinflammation and outcome in acute stroke. Blood was obtained, prehospital, on an mobile stroke unit. Outcomes were biomarker concentrations, modified Rankin Scale score, and National Institutes of Health Stroke Scale score.

RESULTS

Forty-one adults were analyzed, including 15 patients treated on the mobile stroke unit between August 2021 and April 2022, and 26 healthy controls to establish biomarker reference levels. Median patient age was 74 (range, 36-97) years, 60% were female, and 80% White. Ten (67%) were diagnosed as stroke, with 8 (53%) confirmed and 2 likely transient ischemic attack or stroke averted by thrombolysis; 5 were stroke mimics. For strokes, median initial National Institutes of Health Stroke Scale score was 11 (range, 4-19) and 6 (75%) received tPA (tissue-type plasminogen activator). Blood was obtained a median of 58 (range, 36-133) minutes after symptom onset. Within 36 minutes after stroke, plasma IL-6 (interleukin-6), neurofilament light chain, UCH-L1 (ubiquitin C-terminal hydrolase L1), and GFAP (glial fibrillary acidic protein) were elevated by as much as 10 times normal. In EVs, MMP-9 (matrix metalloproteinase-9), CXCL4 (chemokine (C-X-C motif) ligand 4), CRP (C-reactive protein), IL-6, OPN (osteopontin), and PECAM1 (platelet and endothelial cell adhesion molecule 1) were elevated. Inflammatory markers increased rapidly in the first 2 hours and continued rising for 24 hours.

CONCLUSIONS

The neuroinflammatory cascade was found to be activated within 36 to 133 minutes after stroke and progresses rapidly. This is earlier than observed previously in humans and suggests injury from neuroinflammation occurs faster than had been surmised. These findings could inform development of acute immunomodulatory stroke therapies and lead to new diagnostic tools and improved outcomes.

Serum neurofilament light chain in functionally relevant coronary artery disease and adverse cardiovascular outcomes

Background: Functionally relevant coronary artery disease (fCAD), causing symptoms of myocardial ischemia, can currently only be reliably detected with advanced cardiac imaging. Serum neurofilament light chain (sNfL) is a biomarker for neuro-axonal injury known to be elevated by cardiovascular (CV) risk factors and cerebrovascular small-vessel diseases. Due to their pathophysiological similarities with fCAD and the link to CV risk factors, we hypothesised that sNfL may have diagnostic and prognostic value for fCAD and adverse cardiovascular outcomes.Methods: Of the large prospective Basel VIII study (NCT01838148), 4'016 consecutive patients undergoing cardiac work-up for suspected fCAD were included (median age 68 years, 32.5% women, 46.9% with history of CAD). The presence of fCAD was adjudicated using myocardial perfusion imaging single-photon emission tomography (MPI-SPECT) and coronary angiography. sNfL was measured using a high-sensitive single-molecule array assay. All-cause and cardiovascular death, myocardial infarction (MI), and stroke/transient ischaemic attack (TIA) during 5-year follow-up were the prognostic endpoints.Results: The diagnostic accuracy of sNfL for fCAD as quantified by the area under the curve (AUC) was low (0.58, 95%CI 0.56-0.60). sNfL was strongly associated with age, renal dysfunction, and body mass index and was a strong and independent predictor of all-cause death, cardiovascular death, and stroke/TIA but not MI. Time-dependent AUC for cardiovascular-death at 1-year was 0.85, 95%CI 0.80-0.89, and 0.81, 95%CI 0.77-0.86 at 2-years.Conclusion: While sNfL concentrations did not show a diagnostic role for fCAD, in contrast, sNfL was a strong and independent predictor of cardiovascular outcomes, including all-cause death, cardiovascular death and stroke/TIA.

High cholesterol levels change the association of biomarkers of neurodegenerative diseases with dementia risk: Findings from a population-based cohort

INTRODUCTION

This study assessed whether in a population with comorbidity of neurodegenerative and cerebrovascular disease (mixed pathology) the association of glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and phosphorylated tau181 (p-tau181) with dementia risk varied depending on levels of total cholesterol and apolipoprotein E (APOE) ε4 genotype.

METHODS

Plasma biomarkers were measured using Simoa technology in 768 participants of a nested case-control study embedded within an ongoing population-based cohort. Logistic and spline regression models, and receiver operating characteristic curves were calculated.

RESULTS

The strength of the association between GFAP and NfL with risk of a clinical diagnosis of dementia changed depending on cholesterol levels and on APOE ε4 genotype. No significant association was seen with p-tau181.

DISCUSSION

In individuals with mixed pathology blood GFAP and NfL are better predictors of dementia risk than p-tau181, and their associations with dementia risk are amplified by hypercholesterolemia, also depending on APOE ε4 genotype.

HIGHLIGHTS

Cholesterol levels changed the association of blood biomarkers with dementia risk. Blood biomarkers seem to perform differently in community- and clinic-based cohorts. Neurofilament light chain might be a biomarker candidate for dementia risk after stroke.

Elevated neurofilament light chain CSF/serum ratio indicates impaired CSF outflow in idiopathic intracranial hypertension

BACKGROUND

Impaired cerebrospinal fluid (CSF) homeostasis is central to the pathogenesis of idiopathic intracranial hypertension (IIH), although the precise mechanisms involved are still not completely understood. The aim of the current study was to assess the CSF/serum ratio of neurofilament light chain levels (QNfL) as a potential indicator of functional CSF outflow obstruction in IIH patients.

METHODS

NfL levels were measured by single molecule array in CSF and serum samples of 87 IIH patients and in three control groups, consisting of 52 multiple sclerosis (MS) patients with an acute relapse, 21 patients with an axonal polyneuropathy (PNP), and 41 neurologically healthy controls (HC). QNfL was calculated as the ratio of CSF and serum NfL levels. Similarly, we also assessed the CSF/serum ratio of glial fibrillary acidic protein (QGFAP) levels to validate the QNfL data. Routine CSF parameters including the CSF/serum albumin ratio (QAlb) were determined in all groups. Lumbar puncture opening pressure of IIH patients was measured by manometry.

RESULTS

CSF-NfL levels (r = 0.29, p = 0.008) and QNfL (0.40, p = 0.0009), but not serum NfL (S-NfL) levels, were associated with lumbar puncture opening pressure in IIH patients. CSF-NfL levels were increased in IIH patients, MS patients, and PNP patients, whereas sNfL levels were normal in IIH, but elevated in MS and PNP. Remarkably, QNfL (p < 0.0001) as well as QGFAP (p < 0.01) were only increased in IIH patients. QNfL was positively correlated with CSF-NfL levels (r = 0.51, p = 0.0012) and negatively correlated with S-NfL levels (r = - 0.51, p = 0.0012) in HC, while it was only positively associated with CSF-NfL levels in IIH patients (r = 0.71, p < 0.0001). An increase in blood-CSF barrier permeability assessed by QAlb did not lead to a decrease in QNfL in any cohort.

CONCLUSIONS

The observed elevation of QNfL in IIH patients, which was associated with lumbar puncture opening pressure, indicates a reduced NfL transition from the CSF to serum compartment. This supports the hypothesis of a pressure-dependent CSF outflow obstruction to be critically involved in IIH pathogenesis.

Neurofilament light is associated with clinical outcome and hemorrhagic transformation in moderate to severe ischemic stroke

Background

Ischemic stroke is a leading cause of morbidity and mortality worldwide. One possible predictor is the use of biomarkers especially neurofilament light chain (NFL).

Objectives

To explore whether NFL could predict clinical outcome and hemorrhagic transformation in moderate to severe stroke.

Design

Single center prospective cohort study.

Methods

Fifty-one moderate to severe ischemic stroke patients were recruited. Blood NFL was obtained from patients at admission (First sample) and 24-96 hours later (Second sample). NFL was analyzed with the ultrasensitive single molecule array (Simoa). Later, we calculated incremental rate NFL (IRN) by changes in NFL per day from baseline. We evaluated National Institute of Health stroke scale (NIHSS), modified Rankins score (mRs), and the presence of hemorrhagic transformation (HT).

Results

IRN was found to be higher in patients with unfavorable outcome (7.12 vs 24.07, P = .04) as well as Second sample (49.06 vs 71.41, P = .011), while NFL First sample was not significant. IRN had a great correlation with mRS (r = .552, P < .001). Univariate logistic regression model showed OR of IRN and Second sample to be 1.081 (95% CI 1.016-1.149, P = .013) and 1.019 (1.002-1.037, P = .03), respectively. Multiple logistic regression model has shown to be significant. In receiver operating analysis, IRN, Second sample, combined IRN with NIHSS and combined Second sample with NIHSS showed AUC (.744, P = .004; 0.713, P = .01; 0.805, P < .001; 0.803, P < .001, respectively). For HT, First sample and Second sample had significant difference with HT (Z = 2.13, P = .033; Z = 2.487, P = .013, respectively).

Conclusion

NFL was found to correlate and predict clinical outcome. In addition, it was found to correlate with HT.

Serum Neurofilament Identifies Patients With Multiple Sclerosis With Severe Focal Axonal Damage in a 6-Year Longitudinal Cohort

BACKGROUND AND OBJECTIVES

Immunomodulatory therapies reduce the relapse rate but only marginally control disability progression in patients with MS. Although serum neurofilament light chain (sNfL) levels correlate best with acute signs of inflammation (e.g., relapses and gadolinium-enhancing [Gd+] lesions), their role in predicting progressive biology and irreversible axonal damage is less clear. We aimed to determine the ability of sNfL to dissect distinct measures of disease severity and predict future (no) evidence of disease activity (EDA/no evidence of disease activity [NEDA]).

METHODS

One hundred fifty-three of 221 patients with relapsing-remitting MS initially enrolled in the Neurofilament and longterm outcome in MS cohort at the MS outpatient clinic of the University Medical Center Mainz (Germany) met the inclusion criteria for this prospective observational cohort study with a median follow-up of 6 years (interquartile range 4-7 years). Progressive disease forms were excluded. Inclusion criteria consisted of Expanded Disability Status Scale (EDSS) assessment within 3 months and MRI within 12 months around blood sampling at baseline (y0) and follow-up (y6). EDSS progression at y6 had to be confirmed 12 weeks later. sNfL was measured by single-molecule array, and the following additional variables were recorded: therapy, medical history, and detailed MRI parameters (T2 hyperintense lesions, Gd+ lesions, and new persistent T1 hypointense lesions).

RESULTS

Patients experiencing EDSS progression or new persistent T1 lesions at y6 showed increased sNfL levels at y0 compared with stable patients or patients with inflammatory activity only. As a potential readily accessible marker of neurodegeneration, we incorporated the absence of persistent T1 lesions to the NEDA-3 concept (NEDA-3^T1: n = 54, 35.3%; EDA^T1: n = 99, 64.7%) and then evaluated a risk score with factors that distinguish patients with and without NEDA-3^T1 status. Adding sNfL to this risk score significantly improved NEDA-3^T1 prediction (0.697 95% CI 0.616-0.770 vs 0.819 95% CI 0.747-0.878, p < 0.001). Patients with sNfL values ≤8.6 pg/mL showed a 76% risk reduction for EDA^T1 at y6 (hazard ratio 0.244, 95% CI 0.142-0.419, p < 0.001).

DISCUSSION

sNfL levels associate with severe focal axonal damage as reflected by development of persistent T1 lesions. Baseline sNfL values predicted NEDA-3^T1 status at 6-year follow-up.

Acetylation, methylation, and ubiquitination of proteins in experimental ischemic stroke in mice: a bioinformatics analysis

The experimental results available in the ProteomeXchange database (accession code PXD016538) (Simats et al. (2020) Molecular and Cellular Proteomics, 19(12), 1921-1936) obtained using a comprehensive multi-omics approach were analyzed in mouse blood to identify potential biomarkers of ischemic stroke. Acetylation, methylation, and ubiquitination were considered as post-translational modifications. The analysis of the significance of changes in the level of protein modification was evaluated for ischemic tissue in comparison with tissue undamaged by stroke and control taken from mice after sham operation. At the level of statistically significant differences according to the Mann-Whitney test (p < 0.05), 2 proteins were found (Q02248 and Q8BL66); for additional 7 proteins, the differences were at the level of a statistical trend (p < 0.1). For 7 of 9 selected proteins there are reports in the literature, for their association with cerebral ischemia.

Neurofilaments contribution in clinic: state of the art

Neurological biomarkers are particularly valuable to clinicians as they can be used for diagnosis, prognosis, or response to treatment. This field of neurology has evolved considerably in recent years with the improvement of analytical methods, allowing the detection of biomarkers not only in cerebrospinal fluid (CSF) but also in less invasive fluids like blood. These advances greatly facilitate the repeated quantification of biomarkers, including at asymptomatic stages of the disease. Among the various informative biomarkers of neurological disorders, neurofilaments (NfL) have proven to be of particular interest in many contexts, such as neurodegenerative diseases, traumatic brain injury, multiple sclerosis, stroke, and cancer. Here we discuss these different pathologies and the potential value of NfL assay in the management of these patients, both for diagnosis and prognosis. We also describe the added value of NfL compared to other biomarkers currently used to monitor the diseases described in this review.

Biomarker of early neurological deterioration in minor stroke and proximal large vessel occlusion: A pilot study

BACKGROUND

Plasma neurofilament light chain (pNFL) represents one of the scaffolding proteins of central nervous system axonal injury. The aim of this study was to evaluate pNFL as a predictive biomarker for early neurological deterioration (END) in medically managed patients with large vessel occlusion (LVO) and mild presentation (NIHSS < 6).

METHODS

This retrospective study was developed from a prospectively collected stroke database, which was conducted at a large academic comprehensive stroke center in western China. Patients who first presented with acute ischemic stroke (AIS) within 24 h of symptom onset were continuously included. Stroke severity was analyzed at admission using the NIHSS score. The pNFL drawn on admission was analyzed with a novel ultrasensitive single-molecule array.

RESULTS

Thirty-nine consecutive patients were included in the analysis, and 19 (48.72%) patients experienced END. Patients who experienced END had significantly higher pNFL levels (mean, 65.20 vs. 48.28 pg/mL; P < 0.001) and larger infarct volume (mean, 15.46 vs. 9.56 mL; P < 0.001). pNFL was valuable for the prediction of END (OR, 1.170; 95% CI, 1.049-1.306; P = 0.005), even after adjusted for age and sex (OR, 1.178; 95% CI, 1.038-1.323; P = 0.006), blood sampling time, baseline NIHSS, TOAST classification, and infarct volume (OR, 1.168; 95% CI, 1.034-1.320; P = 0.012). The area under the ROC curve was 85.0% (95% CI, 0.731-0.970; P < 0.001). The sensitivity was 73.7%, and the specificity was 80%.

CONCLUSION

END in minor stroke with LVO was distinguishable from those without END following the determination of pNFL in the blood samples within 24 h of onset. The pNFL is a promising biomarker of END in minor stroke with LVO.

CLINICAL TRIAL REGISTRATION

ChiCTR1800020330.

Serum neurofilament light chain levels are correlated with the infarct volume in patients with acute ischemic stroke

Neurofilament light chains (NfLs) are promising biomarkers of neuroaxonal damage in stroke patients. We investigated the correlations between NfL levels and infarct volume, initial stroke severity, and functional outcomes at discharge in patients with acute ischemic stroke. We prospectively included 15 patients with first-ever acute ischemic stroke and 8 age- and sex-matched healthy controls without other neurological disorders. Serum NfL levels were measured using the single-molecule array (Simoa) technique twice within 24 hours of admission (NfL1D) and on the seventh hospital day (NfL7D) in patients with stroke and once in healthy controls. We assessed the infarct volume on diffusion-weighted magnetic resonance imaging using the free software ITK-SNAP. Serum NfL1D levels in stroke patients were significantly higher (28.4 pg/mL; interquartile range [IQR], 43.0) than in healthy controls (14.5 pg/mL; IQR, 3.2; P = .005). Temporal pattern analyses demonstrated that NfL7D levels were increased (114.0 pg/mL; IQR, 109.6) compared to NfL1D levels in all stroke patients (P = .001). There was a strong correlation between NfL7D levels and infarct volume (R = 0.67, P = .007). The difference between NfL1D and NfL7D (NfLdiff levels) was strongly correlated with the infarct volume (R = 0.63; P = .013). However, there was no statistically significant correlation between NfL levels and the initial stroke severity or functional outcomes at discharge. NfL levels in the subacute stage of stroke and the NfL difference between admission and 7th day of hospital were correlated with infarct volume in patients with acute ischemic stroke.

Neurofilament light chain in blood as a diagnostic and predictive biomarker for multiple sclerosis: A systematic review and meta-analysis

Background

Neurofilament light chain (NfL) in cerebrospinal fluid (CSF) is a biomarker of multiple sclerosis (MS). However, CSF sampling is invasive and has limited the clinical application. With the development of highly sensitive single-molecule assay, the accurate quantification of the very low NfL levels in blood become feasible. As evidence being accumulated, we performed a meta-analysis to evaluate the diagnostic and predictive value of blood NfL in MS patients.

Methods

We performed literature search on PubMed, EMBASE, Web of Science and Cochrane Library from inception to May 31, 2022. The blood NfL differences between MS vs. controls, MS vs. clinically isolated syndrome (CIS), progressive MS (PMS) vs. relapsing-remitting MS (RRMS), and MS in relapse vs. MS in remission were estimated by standard mean difference (SMD) and corresponding 95% confidence interval (CI). Pooled hazard ratio (HR) and 95%CI were calculated to predict time to reach Expanded Disability Status Scale (EDSS) score≥4.0 and to relapse.

Results

A total of 28 studies comprising 6545 MS patients and 2477 controls were eligible for meta-analysis of diagnosis value, and 5 studies with 4444 patients were synthesized in analysis of predictive value. Blood NfL levels were significantly higher in MS patients vs. age-matched controls (SMD = 0.64, 95%CI 0.44–0.85, P<0.001), vs. non-matched controls (SMD = 0.76, 95%CI 0.56–0.96, P<0.001) and vs. CIS patients (SMD = 0.30, 95%CI 0.18–0.42, P<0.001), in PMS vs. RRMS (SMD = 0.56, 95%CI 0.27–0.85, P<0.001), and in relapsed patients vs. remitted patients (SMD = 0.54, 95%CI 0.16–0.92, P = 0.005). Patients with high blood NfL levels had shorter time to reach EDSS score≥4.0 (HR = 2.36, 95%CI 1.32–4.21, P = 0.004) but similar time to relapse (HR = 1.32, 95%CI 0.90–1.93, P = 0.155) compared to those with low NfL levels.

Conclusion

As far as we know, this is the first meta-analysis evaluating the diagnosis and predictive value of blood NfL in MS. The present study indicates blood NfL may be a useful biomarker in diagnosing MS, distinguishing MS subtypes and predicting disease worsening in the future.

Neurofilaments in neurologic disorders and beyond

Many neurologic diseases can initially present as a diagnostic challenge and even when a diagnosis is made, monitoring of disease activity, progression and response to therapy may be limited with existing clinical and paraclinical assessments. As such, the identification of disease specific biomarkers provides a promising avenue by which diseases can be effectively diagnosed, monitored and used as a prognostic indicator for long-term outcomes. Neurofilaments are an integral component of the neuronal cytoskeleton, where assessment of neurofilaments in the blood, cerebrospinal fluid (CSF) and diseased tissue has been shown to have value in providing diagnostic clarity, monitoring disease activity, tracking progression and treatment efficacy, as well as lending prognostic insight into long-term outcomes. As such, this review attempts to provide a glimpse into the structure and function of neurofilaments, their role in various neurologic and non-neurologic disorders, including uncommon conditions with recent knowledge of neurofilament-related pathology, as well as their applicability in future clinical practice.

Fluid biomarkers in stroke: From animal models to clinical care

Stroke is a leading cause of death and disability worldwide. Stroke prevention, early diagnosis, and efficient acute treatment are priorities to successfully impact stroke death and disability. Fluid biomarkers may improve stroke differential diagnostic, patient stratification for acute treatment, and post-stroke individualized rehabilitation. In the present work, we characterized the use of stroke animal models in fluid biomarker research through a systematic review of PubMed and Scopus databases, followed by a literature review on the translation to the human stroke care setting and future perspectives in the field. We found increasing numbers of publications but with limited translation to the clinic. Animal studies are very heterogeneous, do not account for several human features present in stroke, and, importantly, only a minority of such studies used human cohorts to validate biomarker findings. Clinical studies have found appealing candidates, both protein and circulating nucleic acids, to contribute to a more personalized stroke care pathway. Still, brain tissue complexity and the fact that different brain pathologies share lesion biomarkers make this task challenging due to biomarker low specificity. Moreover, the study design and lack of validation cohorts may have precluded a formal integration of biomarkers in different steps of stroke diagnosis and treatment. To overcome such issues, recent pivotal studies on biomarker dynamics in individual patients are providing added value to diagnosis and anticipating patients' early prognosis. Presently, the most consistent protein biomarkers for stroke diagnosis and short- and long-term prognosis are associated with tissue damage at neuronal (TAU), axonal (NFL), or astroglial (GFAP and S100β) levels. Most promising nucleic acids are microRNAs (miR), due to their stability in plasma and ease of access. Still, clinical validation and standardized quantitation place them a step behind compared protein as stroke biomarkers. Ultimately, the definition of clinically relevant biomarker panels and optimization of fast and sensitive biomarker measurements in the blood, together with their combination with clinical and neuroimaging data, will pave the way toward personalized stroke care.

Plasma Neurofilament Light Chain Is Associated with Cognitive Impairment after Posterior Circulation Stroke

Background

Neurofilament light chain (NfL) is a biomarker for large-caliber axonal degeneration in the subcortex. The purpose of this research was to examine the relationship between plasma neurofilament light chain (pNfL) and cognitive impairment following a posterior circulation stroke.

Methods

Patients over the age of 18 with their first-ever acute ischemic stroke (AIS) of the posterior cerebral circulation within 24 h of symptom onset were included from July 1, 2017, to December 31, 2019. Blood samples were collected within 48 h after the stroke. The Montreal Cognitive Assessment (MOCA) (MOCA < 26) was adopted to define poststroke cognitive impairment (PSCI) 90 days after stroke onset.

Results

A total of 264 patients were analyzed in this research 101 (38.30%) patients were clinically diagnosed with PSCI. The PNfL concentration was significantly higher in the PSCI group compared with the non-PSCI group (p < 0.001). The pNfL concentration (OR 1.044; p < 0.001) remained to be a significant predictor for PSCI after a multivariable logistic regression analysis, even after adjusting for factors including age, sex, education background (OR 1.044; p < 0.001), baseline NIHSS, infarct volume, and TOAST classification (OR 1.035; p < 0.001). The diagnostic efficacy of pNfL concentration for PSCI was then explored with a ROC analysis. The optimum pNfL concentration threshold was 38.12 pg/ml, with a sensitivity of 78.20%, a specificity of 66.9%, and an AUC of 0.782 (p < 0.001).

Conclusion

This research showed that pNfL concentration, independent of established conventional risk factors, could predict the cognitive impairment in 90 days following posterior circulation stroke.

Neurofilament Light Chain: A Candidate Biomarker of Perioperative Stroke

Perioperative stroke is defined as a brain infarction of ischemic or hemorrhagic etiology that occurs during surgery or within 30 days after surgery. However, identifying perioperative stroke is challenging. Thus, the discovery and validation of neurological biomarkers for perioperative stroke are urgently needed. Neurofilament forms part of the neuronal cytoskeleton and is exclusively expressed in neurons. After disease-related neuroaxonal damage occurs, neurofilament light chain protein is released into the cerebrospinal fluid and blood. Blood neurofilament light chain has recently been shown to serve as a potential marker of interest during the perioperative period. Therefore, the aim of the present review was to give an overview of the current understanding and knowledge of neurofilament light chain as a potential biomarker of perioperative stroke.

Improved prediction of early cognitive impairment in multiple sclerosis combining blood and imaging biomarkers

Disability in multiple sclerosis is generally classified by sensory and motor symptoms, yet cognitive impairment has been identified as a frequent manifestation already in the early disease stages. Imaging- and more recently blood-based biomarkers have become increasingly important for understanding cognitive decline associated with multiple sclerosis. Thus, we sought to determine the prognostic utility of serum neurofilament light chain levels alone and in combination with MRI markers by examining their ability to predict cognitive impairment in early multiple sclerosis. A comprehensive and detailed assessment of 152 early multiple sclerosis patients (Expanded Disability Status Scale: 1.3 ± 1.2, mean age: 33.0 ± 10.0 years) was performed, which included serum neurofilament light chain measurement, MRI markers (i.e. T₂-hyperintense lesion volume and grey matter volume) acquisition and completion of a set of cognitive tests (Symbol Digits Modalities Test, Paced Auditory Serial Addition Test, Verbal Learning and Memory Test) and mood questionnaires (Hospital Anxiety and Depression scale, Fatigue Scale for Motor and Cognitive Functions). Support vector regression, a branch of unsupervised machine learning, was applied to test serum neurofilament light chain and combination models of biomarkers for the prediction of neuropsychological test performance. The support vector regression results were validated in a replication cohort of 101 early multiple sclerosis patients (Expanded Disability Status Scale: 1.1 ± 1.2, mean age: 34.4 ± 10.6 years). Higher serum neurofilament light chain levels were associated with worse Symbol Digits Modalities Test scores after adjusting for age, sex Expanded Disability Status Scale, disease duration and disease-modifying therapy (B = −0.561; SE = 0.192; P = 0.004; 95% CI = −0.940 to −0.182). Besides this association, serum neurofilament light chain levels were not linked to any other cognitive or mood measures (all P-values > 0.05). The tripartite combination of serum neurofilament light chain levels, lesion volume and grey matter volume showed a cross-validated accuracy of 88.7% (90.8% in the replication cohort) in predicting Symbol Digits Modalities Test performance in the support vector regression approach, and outperformed each single biomarker (accuracy range: 68.6–75.6% and 68.9–77.8% in the replication cohort), as well as the dual biomarker combinations (accuracy range: 71.8–82.3% and 72.6–85.6% in the replication cohort). Taken together, early neuro-axonal loss reflects worse information processing speed, the key deficit underlying cognitive dysfunction in multiple sclerosis. Our findings demonstrate that combining blood and imaging measures improves the accuracy of predicting cognitive impairment, highlighting the clinical utility of cross-modal biomarkers in multiple sclerosis.

Plasma neurofilament light chain: A biomarker predicting severity in patients with acute ischemic stroke

Neurofilament light chain (NfL) levels have proved to be a good biomarker in cerebrospinal fluid (CSF) correlating with the degree of neuronal injury and neurodegeneration. However, little is known about the value of plasma neurofilament light chain (pNfL) levels in predicting the clinical prognosis of patients with acute cerebral infarction. This study aimed to explore whether pNfL could be used as a biomarker to predict the severity of the outcomes of acute ischemic stroke (AIS). Patients with AIS were included from the Department of Neurology of the First People's Hospital of Bengbu City from January 2018 to May 2019, as well as health control (HC). The plasma levels of NfL in patients with AIS (n = 60) at 2 days, 7 days, and 6 months after stroke, as well as in HCs (n = 60) were measured by electrochemiluminescence immunoassay(ECL) on the Meso Scale Discovery platform. Stroke severity was analyzed at admission using the National Institutes of Health Stroke Scale score. Functional outcomes were assessed at different times using the modified Rankin Scale (mRS) and Barthel Index. The mean level of pNfL in patients with ischemic stroke (IS) at 2 days (225.86 pg/L) after stroke was significantly higher than that in HC (107.02 pg/L) and gradually increased 7 days after stroke (316.23 pg/L) (P < .0001). The mean level of pNfL in patients with IS at 6 months after stroke was 173.38 pg/L, which was still significantly higher than that of HC. The levels of pNfL at 7 days after stroke independently predicted modified Rankin Scale scores (mRS) (R = 0.621, P < .001), Barthel Index (R = -0.716, P < .001), and National Institutes of Health Stroke Scale (R = -0.736, P < .001). The diagnostic severity and prognosis were evaluated by ROC curve, an area under the receiver operator curve of 0.812 (P = .001, 95% CI: 0.69-0.93) at 7 days. Plasma NfL levels reflect neuronal injury after AIS. It changes with time and has a certain relationship with prognosis and may be a promising biomarker for predicting the severity of neuroaxonal injury in patients with acute IS.

Plasma neurofilament light and its association with all-cause mortality risk among urban middle-aged men and women

BACKGROUND

Neurofilament light chain (NfL) is released into the blood during neuronal damage. NfL is linked to mortality in neurological disorders, remaining unexplored in population studies. We investigated whether initial (v1) and annualized change (δ) in plasma NfL can predict all-cause mortality in middle-aged dementia-free urban adults.

METHODS

Longitudinal data were from 694 participants in the Healthy Aging in Neighborhoods of Diversity Across the Life Span study (HANDLS, mean agev1: 47.8 years, 42% male, 55.8% African American). Plasma NfL was measured prospectively at three visits. Analyses included Cox proportional hazards models for all-cause mortality risk and 4-way decomposition testing for interaction and mediation.

RESULTS

Unlike men, women exhibited a direct association between δNfL (above vs. below median) and all-cause mortality risk in both the minimally (HR = 3.91, 95% CI 1.10-13.9, p = 0.036) and fully adjusted models (HR = 4.92, 95% CI 1.26-19.2, p = 0.022), and for δNfL (per unit increase) in the full model (HR = 1.65, 95% CI 1.04-2.61, p = 0.034). In both models, and among women, 1 standard deviation of NfLv1 was associated with an increased all-cause mortality risk (reduced model: HR = 2.01, 95% CI 1.24-3.25, p = 0.005; full model: HR = 1.75, 95% CI 1.02-2.98, p = 0.041). Only few interactions were detected for cardio-metabolic risk factors. Notably, NfLv1 was shown to be a better prognostic indicator at normal hsCRP values among women, while HbA1c and δNfL interacted synergistically to determine mortality risk, overall.

CONCLUSIONS

These findings indicate that plasma NfL levels at baseline and over time can predict all-cause mortality in women and interacts with hsCRP and HbA1c to predict that risk.

Temporal Patterning of Neurofilament Light as a Blood-Based Biomarker for Stroke: A Systematic Review and Meta-Analysis

Damage to axons is a core feature of ischemic stroke and cerebrovascular disease. The burden of axonal injury is correlated with the acute clinical deficits, the underlying burden of ischemic brain injury, the prognosis of recovery, and may be a meaningful therapeutic target for brain repair. Neurofilament light chain (NfL) has been identified as a blood-based biomarker that reflects neuroaxonal damage resulting from stroke. However, the utility of NfL as a blood-based biomarker in stroke is confounded by studies examining different temporal windows and patient populations. We conducted a systematic review and meta-analysis to verify the utility of blood NfL as a diagnostic, prognostic, and monitoring stroke biomarker. Nineteen studies reporting serum/plasma NfL values for a total of 4,237 distinct patients with stroke were identified. Using available summary data from the 10 studies that employed a common immunoassay platform, we utilized random effects linear mixed modeling and weighted averages to create a phasic model of serum/plasma NfL values in distinct time periods of acute stroke. Weighted averages show that blood NfL levels vary significantly across three distinct temporal epochs of acute (0–7 days), subacute (9–90 days), and chronic (>90 days) stroke with a steep peak in the early subacute period between 14 and 21 days after stroke. Blood NfL values can function as a diagnostic biomarker in distinguishing acute ischemic stroke from transient ischemic attack as well as amongst other cerebrovascular subtypes. Release of NfL into the bloodstream after stroke follows a distinct temporal dynamic that lags several weeks behind stroke onset and reliably associates with a stroke diagnosis despite some variability based on stroke subtype and severity. Identification of these temporal dynamics and the contribution of co- existent cerebrovascular disease states can improve the value of NfL as a stroke biomarker.

The Association of Serum Neurofilament Light Chain and Acute Ischaemic Stroke Is Influenced by Effective Revascularization

Objective

To explore associations of serum neurofilament light chain (sNfL) at admission with clinical deficits and the long-term prognosis of acute ischaemic stroke (AIS).

Methods

We recruited 110 AIS patients with serum sampled at hospital arrival. The concentrations of sNfL were detected by a Simoa HD-1 analyser. We first investigated the determinants of sNfL levels at admission within the study population. Associations of sNfL levels with National Institutes of Health Stroke Scale (NIHSS) scores and modified Rankin Scale (mRS) scores were then tested. We further divided the patients into revascularized and nonrevascularized groups, and the associations of sNfL levels with NIHSS and mRS scores were assessed in these subgroups.

Results

Age, sex, stroke history, and the time between the onset of illness and arrival at the hospital were independent influencing factors of sNfL levels within the study population. The sNfL levels at admission were correlated with the NIHSS scores 7 days after stroke (p = 0.004) across all subjects but showed no correlation with the NIHSS scores at admission (p = 0.293) or the mRS scores 6 months after stroke (p = 0.065). Further analysis revealed that in the nonrevascularized group of AIS patients, the sNfL levels at admission were positively correlated with NIHSS scores (NIHSS at admission, p = 0.005; NIHSS 7 days after stroke, p = 0.003) and negatively correlated with mRS scores (p = 0.011).

Conclusion

sNfL levels at admission could be a potential biomarker for predicting clinical deficits and prognosis in the natural course of AIS.

Neurofilament Light Chain Levels in Multiple Sclerosis Correlate With Lesions Containing Foamy Macrophages and With Acute Axonal Damage

Background and Objectives

To investigate whether white matter lesion activity, acute axonal damage, and axonal density in MS associate with CSF neurofilament light chain (NfL) levels.

Methods

Of 101 brain donors with MS (n = 92 progressive MS, n = 9 relapsing-remitting MS), ventricular CSF was collected, and NfL levels were measured. White matter lesions were classified as active, mixed, inactive, or remyelinated, and microglia/macrophage morphology in active and mixed lesions was classified as ramified, ameboid, or foamy. In addition, axonal density and acute axonal damage were assessed using Bielschowsky and amyloid precursor protein (APP) (immune)histochemistry.

Results

CSF NfL measurements of donors with recent (<1 year) or clinically silent stroke were excluded. CSF NfL levels correlated negatively with disease duration (p = 6.9e-3, r = 0.31). In donors without atrophy, CSF NfL levels correlated positively with the proportion of active and mixed lesions containing foamy microglia/macrophages (p = 9.85e-10 and p = 1.75e-3, respectively), but not with those containing ramified microglia. CSF NfL correlated negatively with proportions of inactive (p = 5.66e-3) and remyelinated lesions (p = 0.03). In the normal appearing pyramid tract, axonal density negatively correlated with CSF NfL levels (Bielschowsky, p = 0.02, r = −0.31), and the presence of acute axonal damage in lesions was related to higher NfL levels (APP, p = 1.17e-6). The amount of acute axonal damage was higher in active lesions with foamy microglia/macrophages and in the rim of mixed lesions with foamy microglia/macrophages when compared with active lesions containing ramified microglia/macrophages (p = 4.6e-3 and p = 0.02, respectively), the center and border of mixed lesions containing ramified microglia/macrophages (center: p = 4.6e-3, border, p = 4.6e-3, and n.s., p = 4.6e-3, respectively), the center of mixed lesions containing foamy microglia/macrophages (p = 4.6e-3 and p = 0.02, respectively), inactive lesions (p = 4.6e-3 and p = 4.6e-3, respectively), and remyelinated lesions (p = 0.03 and p = 0.04, respectively).

Discussion

Our results demonstrated that active and mixed white matter MS lesions with foamy microglia show high acute axonal damage and correlate with elevated CSF NfL levels. Our data support the use of this biomarker to monitor inflammatory demyelinating lesion activity with axonal damage in MS.

Inhibition of the enzyme autotaxin reduces cortical excitability and ameliorates the outcome in stroke

Stroke penumbra injury caused by excess glutamate is an important factor in determining stroke outcome; however, several therapeutic approaches aiming to rescue the penumbra have failed, likely due to unspecific targeting and persistent excitotoxicity, which continued far beyond the primary stroke event. Synaptic lipid signaling can modulate glutamatergic transmission via presynaptic lysophosphatidic acid (LPA) 2 receptors modulated by the LPA-synthesizing molecule autotaxin (ATX) present in astrocytic perisynaptic processes. Here, we detected long-lasting increases in brain ATX concentrations after experimental stroke. In humans, cerebrospinal fluid ATX concentration was increased up to 14 days after stroke. Using astrocyte-specific deletion and pharmacological inhibition of ATX at different time points after experimental stroke, we showed that inhibition of LPA-related cortical excitability improved stroke outcome. In transgenic mice and in individuals expressing a single-nucleotide polymorphism that increased LPA-related glutamatergic transmission, we found dysregulated synaptic LPA signaling and subsequent negative stroke outcome. Moreover, ATX inhibition in the animal model ameliorated stroke outcome, suggesting that this approach might have translational potential for improving the outcome after stroke.

Stroke Proteomics: From Discovery to Diagnostic and Therapeutic Applications

Stroke remains a leading cause of death and disability, with limited therapeutic options and suboptimal tools for diagnosis and prognosis. High throughput technologies such as proteomics generate large volumes of experimental data at once, thus providing an advanced opportunity to improve the status quo by facilitating identification of novel therapeutic targets and molecular biomarkers. Proteomics studies in animals are largely designed to decipher molecular pathways and targets altered in brain tissue after stroke, whereas studies in human patients primarily focus on biomarker discovery in biofluids and, more recently, in thrombi and extracellular vesicles. Here, we offer a comprehensive review of stroke proteomics studies conducted in both animal and human specimen and present our view on limitations, challenges, and future perspectives in the field. In addition, as a unique resource for the scientific community, we provide extensive lists of all proteins identified in proteomic studies as altered by stroke and perform postanalysis of animal data to reveal stroke-related cellular processes and pathways.

Post-Stroke Cognitive Impairment and Dementia

Poststroke cognitive impairment and dementia (PSCID) is a major source of morbidity and mortality after stroke worldwide. PSCID occurs as a consequence of ischemic stroke, intracerebral hemorrhage, or subarachnoid hemorrhage. Cognitive impairment and dementia manifesting after a clinical stroke is categorized as vascular even in people with comorbid neurodegenerative pathology, which is common in elderly individuals and can contribute to the clinical expression of PSCID. Manifestations of cerebral small vessel disease, such as covert brain infarcts, white matter lesions, microbleeds, and cortical microinfarcts, are also common in patients with stroke and likewise contribute to cognitive outcomes. Although studies of PSCID historically varied in the approach to timing and methods of diagnosis, most of them demonstrate that older age, lower educational status, socioeconomic disparities, premorbid cognitive or functional decline, life-course exposure to vascular risk factors, and a history of prior stroke increase risk of PSCID. Stroke characteristics, in particular stroke severity, lesion volume, lesion location, multiplicity and recurrence, also influence PSCID risk. Understanding the complex interaction between an acute stroke event and preexisting brain pathology remains a priority and will be critical for developing strategies for personalized prediction, prevention, targeted interventions, and rehabilitation. Current challenges in the field relate to a lack of harmonization of definition and classification of PSCID, timing of diagnosis, approaches to neurocognitive assessment, and duration of follow-up after stroke. However, evolving knowledge on pathophysiology, neuroimaging, and biomarkers offers potential for clinical applications and may inform clinical trials. Preventing stroke and PSCID remains a cornerstone of any strategy to achieve optimal brain health. We summarize recent developments in the field and discuss future directions closing with a call for action to systematically include cognitive outcome assessment into any clinical studies of poststroke outcome.

Association of Serum Neurofilament Light Chain Concentration and MRI Findings in Older Adults: The Cardiovascular Health Study

BACKGROUND AND OBJECTIVES

Neurofilament light chain (NfL) in blood is a sensitive but nonspecific marker of brain injury. This study sought to evaluate associations between NfL concentration and MRI findings of vascular brain injury in older adults.

METHODS

A longitudinal cohort study included 2 cranial MRI scans performed about 5 years apart and assessed for white matter hyperintensities (WMH) and infarcts. About 1 year before their second MRI, 1,362 participants (median age 77 years, 61.4% women) without a history of TIA or stroke had measurement of 4 biomarkers: NfL, total tau, glial fibrillary acidic protein (GFAP), and ubiquitin carboxyl-terminal hydrolase L1. Most (n = 1,279) also had the first MRI scan, and some (n = 633) had quantitative measurements of hippocampal and WMH. In primary analyses, we assessed associations of NfL with a 10-point white matter grade (WMG) and prevalent infarcts on second MRI and with worsening WMG and incident infarct comparing the 2 scans. A p value <0.0125 (0.05/4) was considered significant for these analyses. We also assessed associations with hippocampal and WMH volume.

RESULTS

In fully adjusted models, log2(NfL) concentration was associated with WMG (β = 0.27; p = 2.3 × 10-4) and worsening WMG (relative risk [RR] 1.24; p = 0.0022), but less strongly with prevalent brain infarcts (RR 1.18; p = 0.013) and not with incident brain infarcts (RR 1.18; p = 0.18). Associations were also present with WMH volume (β = 2,242.9, p = 0.0036). For the other 3 biomarkers, the associations for log2 (GFAP) concentration with WMG and worsening WMG were significant.

DISCUSSION

Among older adults without a history of stroke, higher serum NfL concentration was associated with covert MRI findings of vascular brain injury, especially the burden of WMH and its worsening. Whether these results offer opportunities for the use of NfL as a noninvasive biomarker of WMH or to control vascular risk factors remains to be determined.

Neurodegeneration and convergent factors contributing to the deterioration of the cytoskeleton in Alzheimer's disease, cerebral ischemia and multiple sclerosis (Review)

The cytoskeleton is the main intracellular structure that determines the morphology of neurons and maintains their integrity. Therefore, disruption of its structure and function may underlie several neurodegenerative diseases. This review summarizes the current literature on the tau protein, microtubule-associated protein 2 (MAP2) and neurofilaments as common denominators in pathological conditions such as Alzheimer's disease (AD), cerebral ischemia, and multiple sclerosis (MS). Insights obtained from experimental models using biochemical and immunocytochemical techniques highlight that changes in these proteins may be potentially used as protein targets in clinical settings, which provides novel opportunities for the detection, monitoring and treatment of patients with these neurodegenerative diseases.

Diagnostic and Prognostic Blood Biomarkers in Transient Ischemic Attack and Minor Ischemic Stroke: An Up-To-Date Narrative Review

INTRODUCTION

Early diagnosis and correct risk stratification in patients with transient ischemic attack (TIA) and minor ischemic stroke (MIS) is crucial for the high rate of subsequent disabling stroke. Although highly improved, diagnosis and prognostication of TIA/MIS patients remain still based on clinical and neuroimaging findings, with some inter-rater variability even among trained neurologists.

OBJECTIVES

To provide an up-to-date overview of diagnostic and prognostic blood biomarkers in TIA and MIS patients.

MATERIAL AND METHODS

We performed a bibliographic search on PubMed database with last access on July 10^th 2021. More than 680 articles were screened and we finally included only primary studies on blood biomarkers.

RESULTS

In a narrative fashion, we discussed about blood biomarkers investigated in TIA/MIS patients, including inflammatory, thrombosis, neuronal injury and cardiac analytes, antibodies and microRNAs. Other soluble molecules have been demonstrated to predict the risk of recurrent cerebrovascular events or treatment response in these patients. A rapid point of care assay, combining the determination of different biomarkers, has been developed to improve triage recognition of acute cerebrovascular accidents.

CONCLUSIONS

The implementation of blood biomarkers in the clinical management of TIA/MIS could ameliorate urgent identification, risk stratification and individual treatment choice. Large prospective and longitudinal studies, adopting standardized sampling and analytic procedures, are needed to clarify blood biomarkers kinetic and their relationship with TIA and minor stroke etiology.

Plasma Neurofilament Light Chain Predicts Mortality and Long-Term Neurological Outcomes in Patients with Intracerebral Hemorrhage

Patients with intracerebral hemorrhage (ICH) often suffer from heterogeneous long-term neurological deficits, such as cognitive decline. Our ability to measure secondary brain injury to predict the long-term outcomes of these patients is limited. We investigated whether the blood neurofilament light chain (NfL) can monitor brain injury and predict long-term outcomes in patients with ICH. We enrolled 300 patients with first-episode ICH within 24 h recruited in the Chinese Cerebral Hemorrhage Mechanisms and Intervention study cohort from January 2019 to June 2020. Patients were prospectively followed up for 12 months. Blood samples were collected from 153 healthy participants. Plasma NfL levels determined using a single-molecule array revealed a biphasic increase in plasma NfL in ICH patients compared to healthy controls, with the first peak at around 24 h and a second elevation from day 7 through day 14 post-ICH. Plasma NfL levels were positively correlated with hemorrhage volume, National Institute of Health Stroke Scale, and Glasgow Coma Scale scores of ICH patients. Higher NfL concentration within 72 h after ictus was independently associated with 6- and 12-month worsened functional outcomes (modified Rankin Scale ≥ 3) and higher all-cause mortality. Magnetic resonance imaging and cognitive function evaluation were available for 26 patients at 6 months post-ICH, and NfL levels measured 7 days post-ictus correlated with decreased white matter fiber integrity and poor cognitive function at 6 months after stroke. These findings suggest that blood NfL is a sensitive marker for monitoring axonal injury post-ICH and can predict long-term functional ability and survival.

A Combined Clinical and Serum Biomarker-Based Approach May Allow Early Differentiation Between Patients With Minor Stroke and Transient Ischemic Attack as Well as Mid-term Prognostication

Background: Early differentiation between transient ischemic attack (TIA) and minor ischemic stroke (MIS) impacts on the patient's individual diagnostic work-up and treatment. Furthermore, estimations regarding persisting impairments after MIS are essential to guide rehabilitation programs. This study evaluated a combined clinical- and serum biomarker-based approach for the differentiation between TIA and MIS as well as the mid-term prognostication of the functional outcome, which is applicable within the first 24 h after symptom onset. Methods: Prospectively collected data were used for a retrospective analysis including the neurological deficit at admission (National Institutes of Health Stroke Scale, NIHSS) and the following serum biomarkers covering different pathophysiological aspects of stroke: Coagulation (fibrinogen, antithrombin), inflammation (C reactive protein), neuronal damage in the cellular [neuron specific enolase], and the extracellular compartment [matrix metalloproteinase-9, hyaluronic acid]. Further, cerebral magnetic resonance imaging was performed at baseline and day 7, while functional outcome was evaluated with the modified Rankin Scale (mRS) after 3, 6, and 12 months. Results: Based on data from 96 patients (age 64 ± 14 years), 23 TIA patients (NIHSS 0.6 ± 1.1) were compared with 73 MIS patients (NIHSS 2.4 ± 2.0). In a binary logistic regression analysis, the combination of NIHSS and serum biomarkers differentiated MIS from TIA with a sensitivity of 91.8% and a specificity of 60.9% [area under the curve (AUC) 0.84]. In patients with NIHSS 0 at admission, this panel resulted in a still acceptable sensitivity of 81.3% (specificity 71.4%, AUC 0.69) for the differentiation between MIS (n = 16) and TIA (n = 14). By adding age, remarkable sensitivities of 98.4, 100, and 98.2% for the prediction of an excellent outcome (mRS 0 or 1) were achieved with respect to time points investigated within the 1-year follow-up. However, the specificity was moderate and decreased over time (83.3, 70, 58.3%; AUC 0.96, 0.92, 0.91). Conclusion: This pilot study provides evidence that the NIHSS combined with selected serum biomarkers covering pathophysiological aspects of stroke may represent a useful tool to differentiate between MIS and TIA within 24 h after symptom onset. Further, this approach may accurately predict the mid-term outcome in minor stroke patients, which might help to allocate rehabilitative resources.