Prognostic performance of blood neurofilament light chain protein in hospitalized COVID-19 patients without major central nervous system manifestations: an individual participant data meta-analysis.

BACKGROUND AND AIMS: To investigate the prognostic value of blood neurofilament light chain protein (NfL) levels in the acute phase of coronavirus disease 2019 (COVID-19). METHODS: We conducted an individual participant data (IPD) meta-analysis after screening on MEDLINE and Scopus to May 23rd 2022. We included studies with hospitalized adult COVID-19 patients without major COVID-19-associated central nervous system (CNS) manifestations and with a measurement of blood NfL in the acute phase as well as data regarding at least one clinical outcome including intensive care unit (ICU) admission, need of mechanical ventilation (MV) and death. We derived the age-adjusted measures NfL Z scores and conducted mixed-effects modelling to test associations between NfL Z scores and other variables, encompassing clinical outcomes. Summary receiver operating characteristic curves (SROCs) were used to calculate the area under the curve (AUC) for blood NfL. RESULTS: We identified 382 records, of which 7 studies were included with a total of 669 hospitalized COVID-19 cases (mean age 66.2 ± 15.0 years, 68.1% males). Median NfL Z score at admission was elevated compared to the age-corrected reference population (2.37, IQR: 1.13-3.06, referring to 99th percentile in healthy controls). NfL Z scores were significantly associated with disease duration and severity. Higher NfL Z scores were associated with a higher likelihood of ICU admission, need of MV, and death. SROCs revealed AUCs of 0.74, 0.80 and 0.71 for mortality, need of MV and ICU admission, respectively. CONCLUSIONS: Blood NfL levels were elevated in the acute phase of COVID-19 patients without major CNS manifestations and associated with clinical severity and poor outcome. The marker might ameliorate the performance of prognostic multivariable algorithms in COVID-19.

Serum Neurofilament Light Chain as Biomarker for Cladribine-Treated Multiple Sclerosis Patients in a Real-World Setting.

Serum neurofilament light chain (sNfL) is an intensely investigated biomarker in multiple sclerosis (MS). The aim of this study was to explore the impact of cladribine (CLAD) on sNfL and the potential of sNfL as a predictor of long-term treatment response. Data were gathered from a prospective, real-world CLAD cohort. We measured sNfL at baseline (BL-sNfL) and 12 months (12Mo-sNfL) after CLAD start by SIMOA. Clinical and radiological assessments determined fulfilment of "no evidence of disease activity" (NEDA-3). We evaluated BL-sNfL, 12M-sNfL and BL/12M sNfL ratio (sNfL-ratio) as predictors for treatment response. We followed 14 patients for a median of 41.5 months (range 24.0-50.0). NEDA-3 was fulfilled by 71%, 57% and 36% for a period of 12, 24 and 36 months, respectively. We observed clinical relapses in four (29%), MRI activity in six (43%) and EDSS progression in five (36%) patients. CLAD significantly reduced sNfL (BL-sNfL: mean 24.7 pg/mL (SD ± 23.8); 12Mo-sNfL: mean 8.8 pg/mL (SD ± 6.2); p = 0.0008). We found no correlation between BL-sNfL, 12Mo-sNfL and ratio-sNfL and the time until loss of NEDA-3, the occurrence of relapses, MRI activity, EDSS progression, treatment switch or sustained NEDA-3. We corroborate that CLAD decreases neuroaxonal damage in MS patients as determined by sNfL. However, sNfL at baseline and at 12 months failed to predict clinical and radiological treatment response in our real-world cohort. Long-term sNfL assessments in larger studies are essential to explore the predictive utility of sNfL in patients treated with immune reconstitution therapies.

COVID-19 Affects Serum Brain-Derived Neurotrophic Factor and Neurofilament Light Chain in Aged Men: Implications for Morbidity and Mortality.

BACKGROUND AND METHODS: Severe COVID-19 is known to induce neurological damage (NeuroCOVID), mostly in aged individuals, by affecting brain-derived neurotrophic factor (BDNF), matrix metalloproteinases (MMP) 2 and 9 and the neurofilament light chain (NFL) pathways. Thus, the aim of this pilot study was to investigate BDNF, MMP-2, MMP-9, and NFL in the serum of aged men affected by COVID-19 at the beginning of the hospitalization period and characterized by different outcomes, i.e., attending a hospital ward or an intensive care unit (ICU) or with a fatal outcome. As a control group, we used a novelty of the study, unexposed age-matched men. We also correlated these findings with the routine blood parameters of the recruited individuals. RESULTS: We found in COVID-19 individuals with severe or lethal outcomes disrupted serum BDNF, NFL, and MMP-2 presence and gross changes in ALT, GGT, LDH, IL-6, ferritin, and CRP. We also confirmed and extended previous data, using ROC analyses, showing that the ratio MMPs (2 and 9) versus BDNF and NFL might be a useful tool to predict a fatal COVID-19 outcome. CONCLUSIONS: Serum BDNF and NFL and/or their ratios with MMP-2 and MMP-9 could represent early predictors of NeuroCOVID in aged men.

Serum neurofilament light chain levels in Covid-19 patients without major neurological manifestations.

BACKGROUND: Increased serum levels of neurofilament light chain (sNFL), a biomarker of neuroaxonal damage, have been reported in patients with Covid-19. We aimed at investigating whether sNFL is increased in Covid-19 patients without major neurological manifestations, is associated with disease severity, respiratory and routine blood parameters, and changes longitudinally in the short term. METHODS: sNFL levels were measured with single molecule array (Simoa) technology in 57 hospitalized Covid-19 patients without major neurological manifestations and in 30 neurologically healthy controls. Patients were evaluated for PaO2/FiO2 ratio on arterial blood gas, Brescia Respiratory Covid Severity Scale (BRCSS), white blood cell counts, serum C-reactive protein (CRP), plasma D-dimer, plasma fibrinogen, and serum creatinine at admission. In 20 patients, NFL was also measured on serum samples obtained at a later timepoint during the hospital stay. RESULTS: Covid-19 patients had higher baseline sNFL levels compared to controls, regardless of disease severity. Baseline sNFL correlated with serum CRP and plasma D-dimer in patients with mild disease, but was not associated with measures of respiratory impairment. Longitudinal sNFL levels tended to be higher than baseline ones, albeit not significantly, and correlated with serum CRP and plasma D-dimer. The PaO2/FiO2 ratio was not associated with longitudinal sNFL, whereas BRCSS only correlated with longitudinal sNFL variation. CONCLUSIONS: We provide neurochemical evidence of subclinical axonal damage in Covid-19 also in the absence of major neurological manifestations. This is apparently not fully explained by hypoxic injury; rather, systemic inflammation might promote this damage. However, a direct neurotoxic effect of SARS-CoV-2 cannot be excluded.

Recent Advances in Intermediate Filaments-Volume 1.

We would like to make readers of the second edition of the Special Issue from the International Journal of Molecular Sciences on the Recent Advances in Intermediate Filaments aware of the content of the first edition on this same topic [...].

Prognostic value of serum/plasma neurofilament light chain for COVID-19-associated mortality.

OBJECTIVE: Given the continued spread of coronavirus 2, the early predictors of coronavirus disease 19 (COVID-19) associated mortality might improve patients' outcomes. Increased levels of circulating neurofilament light chain (NfL), a biomarker of neuronal injury, have been observed in severe COVID-19 patients. We investigated whether NfL provides non-redundant clinical value to previously identified predictors of COVID-19 mortality. METHODS: We measured serum or plasma NfL concentrations in a blinded fashion in 3 cohorts totaling 338 COVID-19 patients. RESULTS: In cohort 1, we found significantly elevated NfL levels only in critically ill COVID-19 patients. Longitudinal cohort 2 data showed that NfL is elevated late in the course of the disease, following the two other prognostic markers of COVID-19: decrease in absolute lymphocyte count (ALC) and increase in lactate dehydrogenase (LDH). Significant correlations between ALC and LDH abnormalities and subsequent rise of NfL implicate that the multi-organ failure is the most likely cause of neuronal injury in severe COVID-19 patients. The addition of NfL to age and gender in cohort 1 significantly improved the accuracy of mortality prediction and these improvements were validated in cohorts 2 and 3. INTERPRETATION: A substantial increase in serum/plasma NfL reproducibly enhanced COVID-19 mortality prediction. Combined with other prognostic markers, such as ALC and LDH that are routinely measured in ICU patients, NfL measurements might be useful to identify the patients at a high risk of COVID-19-associated mortality, who might still benefit from escalated care.

Serum neurofilament light protein correlates with unfavorable clinical outcomes in hospitalized patients with COVID-19.

Brain imaging studies of patients with COVID-19 show evidence of macro- and microhemorrhagic lesions, multifocal white matter hyperintensities, and lesions consistent with posterior reversible leukoencephalopathy. Imaging studies, however, are subject to selection bias, and prospective studies are challenging to scale. Here, we evaluated whether serum neurofilament light chain (NFL), a neuroaxonal injury marker, could predict the extent of neuronal damage in a cohort of 142 hospitalized patients with COVID-19. NFL was elevated in the serum of patients with COVID-19 compared to healthy controls, including those without overt neurological manifestations. Higher NFL serum concentrations were associated with worse clinical outcomes. In 100 hospitalized patients with COVID-19 treated with remdesivir, a trend toward lower NFL serum concentrations was observed. These data suggest that patients with COVID-19 may experience neuroaxonal injury and may be at risk for long-term neurological sequelae. Neuroaxonal injury should be considered as an outcome in acute pharmacotherapeutic trials for COVID-19.

Blood neurofilament light chain and total tau levels at admission predict death in COVID-19 patients.

BACKGROUND AND AIMS: Patients infected with SARS-CoV-2 range from asymptomatic, to mild, moderate or severe disease evolution including fatal outcome. Thus, early predictors of clinical outcome are highly needed. We investigated markers of neural tissue damage as a possible early sign of multisystem involvement to assess their clinical prognostic value on survival or transfer to intensive care unit (ICU). METHODS: We collected blood from 104 patients infected with SARS-CoV-2 the day of admission to the emergency room and measured blood neurofilament light chair (NfL), glial fibrillary acidic protein (GFAP), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and total tau protein levels. RESULTS: We found that NfL, GFAP, and tau were significantly increased in patients with fatal outcome, while NfL and UCH-L1 in those needing ICU transfer. ROC and Kaplan-Meier curves indicated that total tau levels at admission accurately predict mortality. CONCLUSIONS: Blood neural markers may provide additional prognostic value to conventional biomarkers used to predict COVID-19 outcome.

Serum neurofilament light chain (sNfL) values in a large cross-sectional population of children with asymptomatic to moderate COVID-19.

BACKGROUND: Serum neurofilament light chain (sNfL) is an established biomarker of neuro-axonal damage in multiple neurological disorders. Raised sNfL levels have been reported in adults infected with pandemic coronavirus disease 2019 (COVID-19). Levels in children infected with COVID-19 have not as yet been reported. OBJECTIVE: To evaluate whether sNfL is elevated in children contracting COVID-19. METHODS: Between May 22 and July 22, 2020, a network of outpatient pediatricians in Bavaria, Germany, the Coronavirus antibody screening in children from Bavaria study network (CoKiBa), recruited healthy children into a cross-sectional study from two sources: an ongoing prevention program for 1-14 years, and referrals of 1-17 years consulting a pediatrician for possible infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We determined sNfL levels by single molecule array immunoassay and SARS-CoV-2 antibody status by two independent quantitative methods. RESULTS: Of the 2652 included children, 148 (5.6%) were SARS-CoV-2 antibody positive with asymptomatic to moderate COVID-19 infection. Neurological symptoms-headache, dizziness, muscle aches, or loss of smell and taste-were present in 47/148 cases (31.8%). Mean sNfL levels were 5.5 pg/ml (SD 2.9) in the total cohort, 5.1 (SD 2.1) pg/ml in the children with SARS-CoV-2 antibodies, and 5.5 (SD 3.0) pg/ml in those without. Multivariate regression analysis revealed age-but neither antibody status, antibody levels, nor clinical severity-as an independent predictor of sNfL. Follow-up of children with pediatric multisystem inflammatory syndrome (n = 14) showed no association with sNfL. CONCLUSIONS: In this population study, children with asymptomatic to moderate COVID-19 showed no neurochemical evidence of neuronal damage.

Blood neurofilament light concentration at admittance: a potential prognostic marker in COVID-19.

OBJECTIVE: To test the hypotheses that blood biomarkers for nervous system injury, serum concentrations of neurofilament light chain protein (NfL) and glial fibrillary acidic protein (GFAp) can serve as biomarkers for disease severity in COVID-19 patients. METHODS: Forty-seven inpatients with confirmed COVID-19 had blood samples drawn on admission for assessing serum biomarkers of CNS injury by Single molecule array (Simoa), NfL and GFAp. Concentrations of NfL and GFAp were analyzed in relation to symptoms, clinical signs, inflammatory biomarkers and clinical outcomes. We used multivariate linear models to test for differences in biomarker concentrations in the subgroups, accounting for confounding effects. RESULTS: In total, 21% (n = 10) of the patients were admitted to an intensive care unit, and the overall mortality rate was 13% (n = 6). Non-survivors had higher serum concentrations of NfL (p < 0.001) upon admission than patients who were discharged alive both in adjusted analyses (p = 2.6 × 10-7) and unadjusted analyses (p = 0.001). The concentrations of NfL in non-survivors increased over repeated measurements; whereas, the concentrations in survivors were stable. The GFAp concentration was also significantly higher in non-survivors than survivors (p = 0.02). CONCLUSION: Increased concentrations of NfL and GFAp in COVID-19 patients on admission may indicate increased mortality risk. Measurement of blood biomarkers for nervous system injury can be useful to detect and monitor CNS injury in COVID-19.

Mechanical and Non-Mechanical Functions of Filamentous and Non-Filamentous Vimentin.

Intermediate filaments (IFs) formed by vimentin are less understood than their cytoskeletal partners, microtubules and F-actin, but the unique physical properties of IFs, especially their resistance to large deformations, initially suggest a mechanical function. Indeed, vimentin IFs help regulate cell mechanics and contractility, and in crowded 3D environments they protect the nucleus during cell migration. Recently, a multitude of studies, often using genetic or proteomic screenings show that vimentin has many non-mechanical functions within and outside of cells. These include signaling roles in wound healing, lipogenesis, sterol processing, and various functions related to extracellular and cell surface vimentin. Extracellular vimentin is implicated in marking circulating tumor cells, promoting neural repair, and mediating the invasion of host cells by viruses, including SARS-CoV, or bacteria such as Listeria and Streptococcus. These findings underscore the fundamental role of vimentin in not only cell mechanics but also a range of physiological functions. Also see the video abstract here https://youtu.be/YPfoddqvz-g.

Cytoskeleton-a crucial key in host cell for coronavirus infection.

The emerging coronavirus (CoV) pandemic is threatening the public health all over the world. Cytoskeleton is an intricate network involved in controlling cell shape, cargo transport, signal transduction, and cell division. Infection biology studies have illuminated essential roles for cytoskeleton in mediating the outcome of host‒virus interactions. In this review, we discuss the dynamic interactions between actin filaments, microtubules, intermediate filaments, and CoVs. In one round of viral life cycle, CoVs surf along filopodia on the host membrane to the entry sites, utilize specific intermediate filament protein as co-receptor to enter target cells, hijack microtubules for transportation to replication and assembly sites, and promote actin filaments polymerization to provide forces for egress. During CoV infection, disruption of host cytoskeleton homeostasis and modification state is tightly connected to pathological processes, such as defective cytokinesis, demyelinating, cilia loss, and neuron necrosis. There are increasing mechanistic studies on cytoskeleton upon CoV infection, such as viral protein‒cytoskeleton interaction, changes in the expression and post-translation modification, related signaling pathways, and incorporation with other host factors. Collectively, these insights provide new concepts for fundamental virology and the control of CoV infection.