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The pathophysiology behind neurological and cognitive sequelae of COVID-19 may be related to dysfunction of the blood-brain barrier (BBB) and previous research indicate transient neuronal injury and glial activation. The aim of this study was to investigate if COVID-19 is related to increased BBB permeability by analyzing leakage of biomarkers such as astrocyte-derived extracellular vesicles (EVs) and S100B. We also investigated whether levels of these biomarkers correlated with self-reported symptoms that persisted > 2 months. The samples in this 1-year follow-up study came from an ongoing longitudinal study of unvaccinated patients hospitalized for COVID-19 at Danderyd University Hospital, Stockholm, Sweden, between April and June 2020. Blood samples were collected at baseline and 4, 8, and 12 months after hospitalization. Information on self-reported clinical symptoms was collected at follow-up visits. A total of 102 patients were enrolled, and 47 completed all follow-up measurements. Peak levels of both biomarkers were observed at 4 months in the subset of 55 patients who were measured at this timepoint. At 12 months, the biomarkers had returned to baseline levels. The biomarkers were not correlated with any of the long-term self-reported symptoms. COVID-19 is associated with transient increased BBB permeability, shown by elevated levels of astrocyte biomarkers in plasma. However, these levels return to baseline 12 months post-infection and do not correlate with long-term symptoms. Further research is needed to unravel the underlying mechanisms causing long-term symptoms in COVID-19 patients., (© 2024. The Author(s).)

Aim of the Study: To investigate serum levels of glial fibrillary acidic protein (GFAP) for evaluation of neurological outcome in cardiac arrest (CA) patients and compare GFAP sensitivity and specificity to that of more studied biomarkers neuron-specific enolas (NSE) and S100B., Method: A prospective observational study was performed in three hospitals in Sweden during 2008-2012. The participants were 125 CA patients treated with therapeutic hypothermia (TH) to 32-34 °C for 24 hours. Samples were collected from peripheral blood (n=125) and the jugular bulb (n=47) up to 108 hours post-CA. GFAP serum levels were quantified using a novel, fully automated immunochemical method. Other biomarkers investigated were NSE and S100B. Neurological outcome was assessed using the Cerebral Performance Categories scale (CPC) and dichotomized into good and poor outcome., Results: GFAP predicted poor neurological outcome with 100% specificity and 14-23% sensitivity at 24, 48 and 72 hours post-CA. The corresponding values for NSE were 27-50% sensitivity and for S100B 21-30% sensitivity when specificity was set to 100%. A logistic regression with stepwise combination of the investigated biomarkers, GFAP, did not increase the ability to predict neurological outcome. No differences were found in GFAP, NSE and S100B levels when peripheral and jugular bulb blood samples were compared., Conclusion: Serum GFAP increase in patients with poor outcome but did not show sufficient sensitivity to predict neurological outcome after CA. Both NSE and S100B were shown to be better predictors. The ability to predict neurological outcome did not increased when combining the three biomarkers., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Introduction: Biomarkers of brain damage and head injury are potentially useful tools in the management of afflicted patients. Particularly S100B has received much attention and has been adapted into clinical guidelines. Alcohol intoxication and higher age (65 years and over) have been used as risk factors for serious complications following head injury. The effect of these factors on S100B levels has not been fully established in a relevant patient cohort., Methods: We prospectively included 621 adult patients with mild traumatic brain injury (TBI) and S100B sampling. Mild TBI was defined as Glasgow Come Scale 14-15 with loss of consciousness and/or amnesia, but without high-risk factors for intracranial complications. These patients would normally require CT scanning according to local and most international guidelines. S100B was sampled within 3 hours following trauma., Results: 280 patients (45%) were intoxicated by alcohol. Alcohol intoxication had no effect on S100B levels (p = 0.65) and the performance of S100B remained unchanged in these patients. 115 patients (22%) were 65 years or older with elevated S100B levels being more common in this group compared to patients under 65 (p = 0.029). Although the sensitivity of S100B was unchanged in older patients, the specificity was poorer., Conclusion: S100B can be used reliably in mild TBI patients with alcohol intoxication. The clinically utility of S100B in older patients may be limited by very poor specificity leading to only a small decrease in CT scanning.