Biomarkers of Neurological Outcome After Aneurysmal Subarachnoid Hemorrhage as Early Predictors at Discharge from an Intensive Care Unit

Hyperbaric oxygen for moderate-to-severe traumatic brain injury: outcomes 5-8 years after injury

The use of hyperbaric oxygen (HBO2) in the field of traumatic brain injury (TBI) is becoming more widespread and increasing yearly, however there are few prognostic reports on long-term functional efficacy. The aim of this study was to assess the functional prognosis of patients with moderate-to-severe TBI 5-8 years following HBO2 treatments and to explore the optimal HBO2 regimen associated with prognosis, using a retrospective study. Clinical data were retrospectively collected as a baseline for patients with moderate-to-severe TBI treated with HBO2 during inpatient rehabilitation from January 2014 to December 2017. The primary outcome measure was the Disability Rating Scale (DRS) and the secondary outcome measure was the Glasgow Outcome Scale. A total of 133 patients enrolled, with 9 (6.8%) dying, 41 (30.8%) remaining moderately disabled or worse (DRS scores 4-29), 83 (62.4%) remaining partially/mildly disabled or no disability (DRS scores 0-3). Logistic regression analysis revealed that age at injury (odds ratio (OR), 0.96; 95% confidence interval (CI), 0.92-0.99), length of intensive care unit stay (OR, 0.94; 95% CI, 0.88-0.99), and HBO2 sessions (OR, 0.97; 95% CI, 0.95-0.99) were variables that independently influenced long-term prognosis. Cubic fitting models revealed that 14 and 21.6 sessions of HBO2 could be effective for moderate and severe TBI, respectively. This study highlighted that HBO2 in moderate-to-severe TBI may contribute to minimize death and reduce overall disability in the long-term. However, clinicians should be cautious of the potential risk of adverse long-term prognosis from excessive HBO2 exposure when tailoring individualized HBO2 regimens for patients with moderate-to-severe TBI. The study was registered on ClinicalTrials.gov (NCT05387018) on March 31, 2022.

Predicting Role of GFAP and UCH-L1 biomarkers in Spontaneous Subarachnoid Hemorrhage: a preliminary study to evaluate in the short-term their correlation with severity of bleeding and prognosis

BACKGROUND

Spontaneous non-traumatic subarachnoid hemorrhage (sSAH) is a severe brain vascular accident. Glial fibrillary acidic protein (GFAP) and ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) can be theoretically assayed to predict a patient's progression, picturing different aspects of clinical failure after sSAH. The study aims to: a) explore the correlation between sSAH blood volume and biomarkers variation; b) evaluate if these can be predictive of the neurogenic response after sSAH and be prognostic of patient outcome; c) establish eventual threshold levels of biomarkers to define patients' clinical outcome.

METHODS

Blood volumetry at CT scan upon admission, GFAP and UCH-L1 were collected at 24 h, at 72 h, and after 7 days from hemorrhage. Trends and cut-off serum sampling were determined. Clinical outcome was assessed with mRS scale at 14 days.

RESULTS

A strong correlation between GFAP and UCH-L1 and blood diffusion volume in all explored serum intervals related to unfavorable outcome. GFAP and UCH-L1 were very early predictors of unfavorable outcomes at 24 h from sSAH (p = 0.002 and 0.011 respectively). Threshold levels of UCH-L1 apparently revealed a very early, early and late predictor of unfavorable outcomes.

CONCLUSION

GFAP and UCH-L1 represent a potential tool for prompt monitoring and customization of therapies in neurosurgical patients.

The game changer: UCH-L1 and GFAP-based blood test as the first marketed in vitro diagnostic test for mild traumatic brain injury

INTRODUCTION

Major organ-based in vitro diagnostic (IVD) tests like ALT/AST for the liver and cardiac troponins for the heart are established, but an approved IVD blood test for the brain has been missing, highlighting a gap in medical diagnostics.

AREAS COVERED

In response to this need, Abbott Diagnostics secured FDA clearance in 2021 for the i-STAT Alinity™, a point-of-care plasma blood test for mild traumatic brain injury (TBI). BioMerieux VIDAS, also approved in Europe, utilizes two brain-derived protein biomarkers: neuronal ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP). These biomarkers, which are typically present in minimal amounts in healthy individuals, are instrumental in diagnosing mild TBI with potential brain lesions. The study explores how UCH-L1 and GFAP levels increase significantly in the bloodstream following traumatic brain injury, aiding in early and accurate diagnosis.

EXPERT OPINION

The introduction of the i-STAT Alinity™ and the Biomerieux VIDAS TBI blood tests mark a groundbreaking development in TBI diagnosis. It paves the way for the integration of TBI biomarker tools into clinical practice and therapeutic trials, enhancing the precision medicine approach by generating valuable data. This advancement is a critical step in addressing the long-standing gap in brain-related diagnostics and promises to revolutionize the management and treatment of mild TBI.

GFAP and UCHL1 in Non-traumatic SAH: The Story thus Far. A Systematic Review of the Literature

OBJECTIVE

Non-traumatic subarachnoid hemorrhage (SAH) is associated with a high percentage of misdiagnosis and poor prognosis. Biomarkers could be useful in the identification, treatment/management guidance, and outcome improvement of SAH patients. The current systematic review aims to investigate the potential role of biomarkers GFAP (Glial Fibrillary Acidic Protein) and UCH-L1 (Ubiquitin C-Terminal Hydrolase L1) in the diagnosis and prognosis of non-traumatic SAH.

METHODS

A systematic search of PubMed, Scopus, and Web of Science databases was conducted from their inception through February 2023.

RESULTS

17 studies met the inclusion criteria and were included in this review. The vast majority of the included studies (82%) were on GFAP. Most studies used blood and/or CSF samples and incorporated multiple measurements through the initial hospitalization days. The majority of identified studies reported significantly higher levels of GFAP and UCHL1 in SAH patients with poor outcomes. There was notable variation in the specimen type and the timing of sampling.

CONCLUSION

Quantification of GFAP and UCHL1 through the initial days of hospitalization shows promise in the prediction of SAH patient outcomes. Further research is nevertheless warranted to confirm these findings and further clarify the use of the two biomarkers in SAH diagnosis and the prediction of severity and secondary events.

Blood-Based Biomarkers for Neuroprognostication in Acute Brain Injury

Acute brain injury causes loss of functionality in patients that often is devastating. Predicting the degree of functional loss and overall prognosis requires a multifaceted approach to help patients, and more so their families, make important decisions regarding plans and goals of care. A variety of blood-based markers have been studied as one aspect of this determination. In this review, we discuss CNS-derived and systemic markers that have been studied for neuroprognostication purposes. We discuss the foundation of each protein, the conditions in which it has been studied, and how the literature has used these markers for interpretation. We also discuss challenges to using each marker in each section as well.

Analysis of Serum Markers of Perioperative Brain Injury and Inflammation Associated with Endovascular Treatment of Intracranial Aneurysms: A Preliminary Study

Embolization is the preferred method for treating intracranial aneurysms due to its less invasive nature. However, recent findings suggest that even uncomplicated embolization may cause structural damage to the brain through ischemic or inflammatory mechanisms. This study aimed to find possible biomarkers of brain injury and inflammation in patients suffering from intracranial aneurysms who underwent endovascular treatment by measuring serological markers indicating brain damage. The study involved 26 patients who underwent uncomplicated intravascular stenting for unruptured intracranial aneurysms between January 2020 and December 2021. Blood samples were collected before the procedure, at 6-12 h, and at 24 h after the procedure. The following protein biomarkers levels were tested with ELISA: S100B, hNSE, TNF, hsCRP, FABP7, NFL, and GP39. Statistical analysis of the results revealed significant increases in serum levels for the four biomarkers: FABP7-before 0.25 (ng/mL) vs. 6-12 h 0.26 (p = 0.012) and vs. 24 h 0.27 (p < 0.001); GP39-before 0.03 (pg/mL) vs. 6-12 h 0.64 (p = 0.011) and vs. 24 h 0.57 (p = 0.001); hsCRP-before 1.65 (μg/mL) vs. 24 h 4.17 (p = 0.037); NFL-before 0.01 (pg/mL) vs. 6-12 h 3.99 (p = 0.004) and vs. 24 h 1.86 (p = 0.033). These biomarkers are recognized as potential indicators of neurovascular damage and should be monitored in clinical settings. Consequently, serum levels of NFL, GP39, hsCRP, and FABP7 measured before and 24 h after endovascular procedures can serve as important markers for assessing brain damage and indicate avenues for further research on biomarkers of neurovascular injury.

Neurocognitive Sequelae and Rehabilitation after Subarachnoid Hemorrhage: Optimizing Outcomes

Subarachnoid hemorrhage (SAH) is a medical emergency that requires immediate intervention. The etiology varies between cases; however, rupture of an intracranial aneurysm accounts for 80% of medical emergencies. Early intervention and treatment are essential to prevent long-term complications. Over the years, treatment of SAH has drastically improved, which is responsible for the rapid rise in SAH survivors. Post-SAH, a significant number of patients exhibit impairments in memory and executive function and report high rates of depression and anxiety that ultimately affect daily living, return to work, and quality of life. Given the rise in SAH survivors, rehabilitation post-SAH to optimize patient outcomes becomes crucial. The review addresses the current rehabilitative strategies to combat the neurocognitive and behavioral issues that may arise following SAH.

A Future Blood Test to Detect Cerebral Aneurysms

Intracranial aneurysms are reported to affect 2-5% of the population. Despite advances in the surgical management of this disease, diagnostic technologies have marginally improved and still rely on expensive or invasive imaging procedures. Currently, there is no blood-based test to detect cerebral aneurysm formation or quantify the risk of rupture. The aim of this review is to summarize current literature on the mechanism of aneurysm formation, specifically studies relating to inflammation, and provide a rationale and commentary on a hypothetical future blood-based test. Efforts should be focused on clinical-translational approaches to create an assay to screen for cerebral aneurysm presence and risk-stratify patients to allow for superior treatment timing and management. Cerebral Aneurysm Blood Test Considerations: There are multiple caveats to development of a putative blood test to detect cerebral aneurysm presence.

The role of the astrocyte in subarachnoid hemorrhage and its therapeutic implications

Subarachnoid hemorrhage (SAH) is an important public health concern with high morbidity and mortality worldwide. SAH induces cell death, blood−brain barrier (BBB) damage, brain edema and oxidative stress. As the most abundant cell type in the central nervous system, astrocytes play an essential role in brain damage and recovery following SAH. This review describes astrocyte activation and polarization after SAH. Astrocytes mediate BBB disruption, glymphatic–lymphatic system dysfunction, oxidative stress, and cell death after SAH. Furthermore, astrocytes engage in abundant crosstalk with other brain cells, such as endothelial cells, neurons, pericytes, microglia and monocytes, after SAH. In addition, astrocytes also exert protective functions in SAH. Finally, we summarize evidence regarding therapeutic approaches aimed at modulating astrocyte function following SAH, which could provide some new leads for future translational therapy to alleviate damage after SAH.

Serum GFAP - reference interval and preanalytical properties in Danish adults

OBJECTIVES

Glial fibrillary acidic protein (GFAP) is a promising biomarker that could potentially contribute to diagnosis and prognosis in neurological diseases. The biomarker is approaching clinical use but the reference interval for serum GFAP remains to be established, and knowledge about the effect of preanalytical factors is also limited.

METHODS

Serum samples from 371 apparently healthy reference subjects, 21-90 years of age, were measured by a single-molecule array (Simoa) assay. Continuous reference intervals were modelled using non-parametric quantile regression and compared with traditional age-partitioned non-parametric reference intervals established according to the Clinical and Laboratory Standards Institute (CLSI) guideline C28-A3. The following preanalytical conditions were also examined: stability in whole blood at room temperature (RT), stability in serum at RT and -20 °C, repeated freeze-thaw cycles, and haemolysis.

RESULTS

The continuous reference interval showed good overall agreement with the traditional age-partitioned reference intervals of 25-136 ng/L, 34-242 ng/L, and 5-438 ng/L for the age groups 20-39, 40-64, and 65-90 years, respectively. Both types of reference intervals showed increasing levels and variability of serum GFAP with age. In the preanalytical tests, the mean changes from baseline were 2.3% (95% CI: -2.4%, 6.9%) in whole blood after 9 h at RT, 3.1% (95% CI: -4.5%, 10.7%) in serum after 7 days at RT, 10.4% (95% CI: -6.0%, 26.8%) in serum after 133 days at -20 °C, and 10.4% (95% CI: 9.5%, 11.4%) after three freeze-thaw cycles.

CONCLUSIONS

The study establishes age-dependent reference ranges for serum GFAP in adults and demonstrates overall good stability of the biomarker.

Neurofilament light chain and S100B serum levels are associated with disease severity and outcome in patients with aneurysmal subarachnoid hemorrhage

Objectives

Serum neurofilament light chain (NfL) is a biomarker for neuroaxonal damage, and S100B is a blood marker for cerebral damage. In the present study, we investigated the relationship between serum NfL and S100B levels, severity, and outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH).

Methods

We prospectively recruited aSAH patients and healthy controls between January 2016 and January 2021. Clinical results included mortality and poor outcomes (modified Rankin scale score of 3-6) after 6 months. The ultrasensitive Simoa technique was used to evaluate NfL levels in the blood, and ELISA was used to detect S100B.

Results

A total of 91 patients and 25 healthy controls were included in the study, with a death rate of 15.4%. The group of aSAH patients had significantly higher serum levels of NfL and S100B (P &lt; 0.01). Furthermore, the levels of NfL and S100B increased when the Hunt-Hess, World Federation of Neurological Surgeons (WFNS), and Fisher grades increased (P &lt; 0.01). Serum NfL and S100B levels were linked to poor prognoses and low survival rates. The blood levels of NfL and S100B were found to be an independent predictor related to 6-month mortality in multivariable analysis. Additionally, the areas under the curves for NfL and S100B levels in serum were 0.959 and 0.912, respectively; the clinical diagnostic critical thresholds were 14.275 and 26.54 pg/ml, respectively; sensitivities were 0.947 and 0.921, and specificities were 0.849 and 0.811.

Conclusions

The NfL and S100B values for aSAH patients within 12 days of admission were considerably associated with Hunt-Hess grade, WFNS, and Fisher grade. The higher the grade, the higher the NfL and S100B value, and the poorer the prognosis. Serum NfL and S100B values could be feasible biomarkers to predict the clinical prognosis of patients with aSAH.

Effects of Dexmedetomidine Combined with Intravenous Anesthesia on Oxidative Stress Index, Postoperative Sleep Quality, and Brain Function in HICH Patients

To investigate the effects of dexmedetomidine combined with intravenous anesthesia on oxidative emergency indicators, postoperative sleep quality, and brain function in patients with hypertensive cerebral hemorrhage (HICH), a total of 285 HICH patients admitted to our hospital from February 2020 to February 2021 were selected. The combined anesthesia group (n = 142) and the control group (n = 143) were established by the random number table method. The control group received conventional intravenous anesthesia, and the combined anesthesia group received dexmedetomidine combined intravenous anesthesia. Two groups of patients before and after operation was observed vital signs, oxidative stress index difference, comparing each time, the change of the two groups of brain function index, adverse reactions occurred between observation group, and the postoperative period of Pittsburgh Sleep Quality Index Scale (PSQI) score as a result, the Pearson correlation coefficient analysis of oxidative stress level and the correlation of HICH patients sleep quality. After operation, the mean arterial pressure (MAP) and heart rate (HR) of patients in both groups decreased significantly. The MAP level in the combined anesthesia group significantly increased compared to the control group, and the HR level decreased significantly than the control group (all P < 0.05). The levels of TNF-α, IL-6 and MDA in both groups increased significantly on day 7 after operation compared with before operation, but the indexes in the combined anesthesia group significantly decreased compared with the control group (P < 0.05). The level of superoxide dismutase (SOD) in both groups significantly decreased compared to that before operation, and the index value in combined anesthesia group significantly increased compared to that in the control group (P < 0.05). After surgery, the levels of central nerve specific protein (S100-β) and neuron specific enolase (NSE) in 2 groups increased with time, and the indexes in the combined anesthesia group significantly decreased compared to the control group (all P < 0.05). The incidence of adr in combined anesthesia group decreased significantly than that in control group (P < 0.05). After surgery, PSQI scores of the two groups showed a downward trend with time extension, and scores of the combined anesthesia group decreased significantly than those of the control group at 24 h, 48 h and 7 d after surgery (all P < 0.05). Pearson's correlation coefficient was used to analyze that TNF-α, IL-6, and MDA levels were positively correlated with PSQI score, while SOD level was negatively correlated with PSQI score (all P < 0.05). Dexmedetomidine combined with intravenous anesthesia can significantly improve the vital signs and oxidative stress response of HICH patients, effectively reduce the risk of adverse reactions, have little impact on the brain function of patients, and can improve the postoperative sleep quality of patients. This operation is worthy of clinical application. In addition, this study further analyzed the influence mechanism of postoperative sleep quality in patients with HICH and showed that TNF-α, IL-6, MDA, and SOD were all correlated with sleep quality in patients with HICH, suggesting that follow-up detection of these indicators has positive significance in improving the prognosis of patients.

Blood GFAP as an emerging biomarker in brain and spinal cord disorders

Blood-derived biomarkers for brain and spinal cord diseases are urgently needed. The introduction of highly sensitive immunoassays led to a rapid increase in the number of potential blood-derived biomarkers for diagnosis and monitoring of neurological disorders. In 2018, the FDA authorized a blood test for clinical use in the evaluation of mild traumatic brain injury (TBI). The test measures levels of the astrocytic intermediate filament glial fibrillary acidic protein (GFAP) and neuroaxonal marker ubiquitin carboxy-terminal hydrolase L1. In TBI, blood GFAP levels are correlated with clinical severity and extent of intracranial pathology. Evidence also indicates that blood GFAP levels hold the potential to reflect, and might enable prediction of, worsening of disability in individuals with progressive multiple sclerosis. A growing body of evidence suggests that blood GFAP levels can be used to detect even subtle injury to the CNS. Most importantly, the successful completion of the ongoing validation of point-of-care platforms for blood GFAP might ameliorate the decision algorithms for acute neurological diseases, such as TBI and stroke, with important economic implications. In this Review, we provide a systematic overview of the evidence regarding the utility of blood GFAP as a biomarker in neurological diseases. We propose a model for GFAP concentration dynamics in different conditions and discuss the limitations that hamper the widespread use of GFAP in the clinical setting. In our opinion, the clinical use of blood GFAP measurements has the potential to contribute to accelerated diagnosis and improved prognostication, and represents an important step forward in the era of precision medicine.

DAMPs and RAGE Pathophysiology at the Acute Phase of Brain Injury: An Overview

Early or primary injury due to brain aggression, such as mechanical trauma, hemorrhage or is-chemia, triggers the release of damage-associated molecular patterns (DAMPs) in the extracellular space. Some DAMPs, such as S100B, participate in the regulation of cell growth and survival but may also trigger cellular damage as their concentration increases in the extracellular space. When DAMPs bind to pattern-recognition receptors, such as the receptor of advanced glycation end-products (RAGE), they lead to non-infectious inflammation that will contribute to necrotic cell clearance but may also worsen brain injury. In this narrative review, we describe the role and ki-netics of DAMPs and RAGE at the acute phase of brain injury. We searched the MEDLINE database for “DAMPs” or “RAGE” or “S100B” and “traumatic brain injury” or “subarachnoid hemorrhage” or “stroke”. We selected original articles reporting data on acute brain injury pathophysiology, from which we describe DAMPs release and clearance upon acute brain injury, and the implication of RAGE in the development of brain injury. We will also discuss the clinical strategies that emerge from this overview in terms of biomarkers and therapeutic perspectives

Brain-Specific Biomarkers as Mortality Predictors after Aneurysmal Subarachnoid Haemorrhage

Aneurysmal subarachnoid haemorrhage (aSAH) is a serious condition with a high mortality and high permanent disability rate for those who survive the initial haemorrhage. The purpose of this study was to investigate markers specific to the central nervous system as potential in-hospital mortality predictors after aSAH. In patients with an external ventricular drain, enolase, S100B, and GFAP levels were measured in the blood and cerebrospinal fluid (CSF) on days 1, 2, and 3 after aSAH. Compared to survivors, non-survivors showed a significantly higher peak of S100B and enolase levels in the blood (S100B: 5.7 vs. 1.5 ng/mL, p = 0.031; enolase: 6.1 vs. 1.4 ng/mL, p = 0.011) and the CSF (S100B: 18.3 vs. 0.9 ng/mL, p = 0.042; enolase: 109.2 vs. 6.1 ng/mL, p = 0.015). Enolase showed the highest level of predictability at 1.8 ng/mL in the blood (AUC of 0.873) and 80.0 ng/mL in the CSF (AUC of 0.889). The predictive ability of S100B was also very good with a threshold of 5.7 ng/mL in the blood (AUC 0.825) and 4.5 ng/mL in the CSF (AUC 0.810). In conclusion, enolase and S100B, but not GFAP, might be suitable as biomarkers for the early prediction of in-hospital mortality after aSAH.