Neurofilament light chains to assess sepsis-associated encephalopathy: Are we on the track toward clinical implementation? (original) (raw)
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PLOS ONE
Sepsis-associated encephalopathy (SAE) contributes to mortality and neurocognitive impairment of sepsis patients. Neurofilament (Nf) light (NfL) and heavy (NfH) chain levels as biomarkers for neuroaxonal injury were not evaluated in cerebrospinal fluid (CSF) and plasma of patients with sepsis-associated encephalopathy (SAE) before. We conducted a prospective, pilot observational study including 20 patients with septic shock and five patients without sepsis serving as controls. The assessment of SAE comprised a neuropsychiatric examination, electroencephalography (EEG), magnetic resonance imaging (MRI) and delirium screening methods including the confusion assessment method for the ICU (CAM-ICU) and the intensive care delirium screening checklist (ICDSC). CSF Nf measurements in sepsis patients and longitudinal plasma Nf measurements in all participants were performed on days 1, 3 and 7 after study inclusion. Plasma NfL levels increased in sepsis patients over time (p = 0.0063) and remained stable in patients without sepsis. Plasma NfL values were significantly higher in patients with SAE (p = 0.011), significantly correlated with the severity of SAE represented by ICDSC values (R = 0.534, p = 0.022) and correlated with a poorer functional outcome after 100 days (R =-0.535, p = 0.0003). High levels of CSF Nf were measured in SAE patients. CSF NfL levels were higher in non-survivors (p = 0.012) compared with survivors and correlated with days until death (R =-0.932, p<0.0001) and
Critical care (London, England), 2017
Brain homeostasis deteriorates in sepsis, giving rise to a mostly reversible sepsis-associated encephalopathy (SAE). Some survivors experience chronic cognitive dysfunction thought to be caused by permanent brain injury. In this study, we investigated neuroaxonal pathology in sepsis. We conducted a longitudinal, prospective translational study involving (1) experimental sepsis in an animal model; (2) postmortem studies of brain from patients with sepsis; and (3) a prospective, longitudinal human sepsis cohort study at university laboratory and intensive care units (ICUs). Thirteen ICU patients with septic shock, five ICU patients who died as a result of sepsis, fourteen fluid-resuscitated Wistar rats with fecal peritonitis, eleven sham-operated rats, and three human and four rat control subjects were included. Immunohistologic and protein biomarker analysis were performed on rat brain tissue at baseline and 24, 48, and 72 h after sepsis induction and in sham-treated rats. Immunohist...
Sepsis-associated encephalopathy: A review of literature
Neurology India
Sepsis is a leading cause of death in medical and surgical intensive care units (ICUs). Disturbance of consciousness of varying severity is an early warning sign of developing sepsis in the majority of cases. Sepsis-associated encephalopathy (SAE) is the most frequent type of encephalopathy in the ICU and is defined as a state of diffuse cerebral dysfunction caused by the inflammatory response of the body to various infections, where the inflammatory process does not affect the central nervous system (CNS) directly and the primary symptom is a disturbed level of consciousness. The aim of this comprehensive review was to collect the latest scientific knowledge regarding the epidemiology, clinical aspects, pathogenesis, diagnosis, and possible prevention strategies related to SAE.
Serum Neurofilament Light Protein Predicts Clinical Outcome in Traumatic Brain Injury
Alzheimer's & Dementia, 2016
Axonal white matter injury is believed to be a major determinant of adverse outcomes following traumatic brain injury (TBI). We hypothesized that measurement of neurofilament light protein (NF-L), a protein found in long white-matter axons, in blood samples, may serve as a suitable biomarker for neuronal damage in TBI patients. To test our hypotheses, we designed a study in two parts: i) we developed an immunoassay based on Single molecule array technology for quantification of NF-L in blood, and ii) in a proof-of-concept study, we tested our newly developed method on serial serum samples from severe TBI (sTBI) patients (n = 72) and controls (n = 35). We also compared the diagnostic and prognostic utility of NF-L with the established blood biomarker S100B. NF-L levels were markedly increased in sTBI patients compared with controls. NF-L at admission yielded an AUC of 0.99 to detect TBI versus controls (AUC 0.96 for S100B), and increased to 1.00 at day 12 (0.65 for S100B). Importantly, initial NF-L levels predicted poor 12-month clinical outcome. In contrast, S100B was not related to outcome. Taken together, our data suggests that measurement of serum NF-L may be useful to assess the severity of neuronal injury following sTBI. Traumatic brain injury (TBI) is the most common cause of death and disability following blunt trauma among young people worldwide 1. In clinical setting, severity of TBI is commonly classified using Glasgow Coma Scale (GCS), where severe TBI (sTBI) has a GCS score of 3-8. Structural damage following sTBI may be detected by advanced magnetic resonance (MRI) techniques, but is not alone sufficient to predict long-term clinical outcome 2,3. In addition, clinical variables such as age, GCS, pupil reactivity and the extent or grade of damage on imaging have shown some promise in predicting outcome following TBI, however, with limitation 4. Axonal white matter injury has been hypothesized to be the primary determinant of outcome following both mild and severe TBI 5. Neurofilament light (NF-L) is a CNS-enriched protein, abundantly expressed in the long myelinated subcortical white matter axons 6. Together with the neurofilament medium (NF-M) and heavy (NF-H) subunits, NF-L is one of the scaffolding proteins of the neural cytoskeleton, with important roles in axonal and dendritic branching and growth 7. In the context of TBI, measurement NF-L in cerebrospinal fluid (CSF) has shown prognostic utility, both for mild and sTBI 8. However, owing to the invasive nature of lumbar puncture for accessing CSF, it may not always be practical to perform repeated lumbar punctures on a routine clinical basis in TBI cases, and thus blood-based biomarkers are more preferable. The current most commonly used blood biomarkers for brain injury, S100 calcium binding protein B (S100B) and neuron-specific enolase (NSE), where the former is used in the emergency setting instead of CT scan to rule out mild TBI have limited diagnostic and prognostic value 9-11. A major challenge of developing blood-based tests has been the lack of highly sensitive immunochemical methods for detection of CNS-specific markers in peripheral blood. We have recently measured tau, a cortical
Sepsis-associated encephalopathy: not just delirium
Clinics, 2011
Sepsis is a major cause of mortality and morbidity in intensive care units. Organ dysfunction is triggered by inflammatory insults and tissue hypoperfusion. The brain plays a pivotal role in sepsis, acting as both a mediator of the immune response and a target for the pathologic process. The measurement of brain dysfunction is difficult because there are no specific biomarkers of neuronal injury, and bedside evaluation of cognitive performance is difficult in an intensive care unit. Although sepsis-associated encephalopathy was described decades ago, it has only recently been subjected to scientific scrutiny and is not yet completely understood. The pathophysiology of sepsisassociated encephalopathy involves direct cellular damage to the brain, mitochondrial and endothelial dysfunction and disturbances in neurotransmission. This review describes the most recent findings in the pathophysiology, diagnosis, and management of sepsis-associated encephalopathy and focuses on its many presentations.
In critically ill COVID-19 patients, the risk of long-term neurological consequences is just beginning to be appreciated. While recent studies have identified that there is an increase in structural injury to the nervous system in critically ill COVID-19 patients, there is little known about the relationship of COVID-19 neurological damage to the systemic inflammatory diseases also observed in COVID-19 patients. The purpose of this pilot observational study was to examine the relationships between serum neurofilament light protein (NfL, a measure of neuronal injury) and co-morbid cardiovascular disease (CVD) and neurological complications in COVID-19 positive patients admitted to the intensive care unit (ICU). In this observational study of one-hundred patients who were admitted to the ICU in Tucson, Arizona between April and August 2020, 89 were positive for COVID-19 (COVID-pos) and 11 was COVID-negative (COVID-neg). A healthy control group (n=8) was examined for comparison. The primary outcomes and measures were subject demographics, serum NfL, presence and extent of CVD, diabetes, sequential organ failure assessment score (SOFA), presence of neurological complications, and blood chemistry panel data. COVID-pos patients in the ICU had significantly higher mean levels of Nfl (229.6 ± 163 pg/ml) compared to COVID-neg ICU patients (19.3 ± 5.6 pg/ml), Welch’s t-test, p =.01 and healthy controls (12.3 ± 3.1 pg/ml), Welch’s t-test p =.005. Levels of Nfl in COVID-pos ICU patients were significantly higher in patients with concomitant CVD and diabetes (n=35, log Nfl 1.6±.09), and correlated with higher SOFA scores (r=.5, p =.001). These findings suggest that in severe COVID-19 disease, the central neuronal and axonal damage in these patients may be driven, in part, by the level of systemic cardiovascular disease and peripheral inflammation. Understanding the contributions of systemic inflammatory disease to central neurological degeneration in these COVID-19 survivors will be important to the design of interventional therapies to prevent long-term neurological and cognitive dysfunction.
Blood neurofilament light concentration at admittance: a potential prognostic marker in COVID-19
ObjectiveTo test the hypotheses that blood concentrations of neurofilament light chain protein (NfL) and glial fibrillary acidic protein (GFAp) can serve as biomarkers for disease severity in COVID-19 patients.MethodsForty-seven inpatients with confirmed COVID-19 had blood samples drawn on admission for assessing serum biomarkers of CNS injury by Single molecule array (Simoa). 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.ResultsIn total, 21 % (n = 10) of the patients were admitted to an intensive care unit, whereas the overall mortality rate was 13 % (n = 6). Non-survivors had higher serum concentrations of NfL than patients who were discharged alive both in adjusted analyses (p = 2.6 × 10−7) and unadjusted analyses (p = 0.001). Serum concentrations of GFAp w...