On the release and half-life of S100B protein in the peripheral blood of melanoma patients

Reconsidering S100B: Why it is time to abandon its use in detecting disease recurrence in stage III melanoma patients

BACKGROUND

Especially in the era of successful systemic therapy, there is an urgent need to detect early disease recurrence in stage III melanoma patients. This study investigates if serum S100 calcium-binding protein B (S100B) can detect disease recurrence in stage III melanoma patients.

METHODS

A retrospective cohort study was conducted at the University Medical Center Groningen (UMCG). Adult AJCC 8th stage III melanoma patients in whom serum S100B was measured as part of follow-up from January 2010 until April 2023 were included. The association between serum S100B and disease recurrence was evaluated using standard definitions for sensitivity and positive predictive value (PPV).

RESULTS

Overall, 147 patients were included (mean age was 60.4 years, 53.1 % were female). Most patients were classified as stage IIIB (39, 26.5 %) and IIIC (73, 49.7 %). During median follow-up of 56 months, 69 (46.9 %) patients experienced disease recurrence. Seventeen out of 18 patients with elevated serum S100B (≥0.15 μg/L) experienced disease recurrence (PPV of 94.4 %). However, 52 out of 69 patients with disease recurrence had normal serum S100B (sensitivity of 24.6 %). Eight out of 17 (47.1 %) patients were asymptomatic (P = 0.608), twelve (70.6 %) patients had at least four distant metastases (P < 0.001).

CONCLUSION

The clinical value of serum S100B to detect disease recurrence in stage III melanoma patients is negligible since only one out of four patients with disease recurrence have elevated serum S100B. Furthermore, half of stage III melanoma patients with elevated S100B experienced symptoms, and most patients already have multiple distant metastases.

S100B, Actor and Biomarker of Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) accounts for approximately 80% of all TBI cases and is a growing source of morbidity and mortality worldwide. To improve the management of children and adults with mTBI, a series of candidate biomarkers have been investigated in recent years. In this context, the measurement of blood biomarkers in the acute phase after a traumatic event helps reduce unnecessary CT scans and hospitalizations. In athletes, improved management of sports-related concussions is also sought to ensure athletes’ safety. S100B protein has emerged as the most widely studied and used biomarker for clinical decision making in patients with mTBI. In addition to its use as a diagnostic biomarker, S100B plays an active role in the molecular pathogenic processes accompanying acute brain injury. This review describes S100B protein as a diagnostic tool as well as a potential therapeutic target in patients with mTBI.

Serum S100B Levels in Patients with Liver Cirrhosis and Hepatic Encephalopathy

Hepatic encephalopathy (HE) is one of the main complications of liver cirrhosis (LC) and is classified into minimal hepatic encephalopathy (MHE) and overt hepatic encephalopathy (overt HE). S100B is expressed mainly in astrocytes and other glial cells, and S100B has been reported to be associated with various neurological disorders. The present study aimed to investigate the diagnostic ability of serum S100B to discriminate the grade of HE and the parameters correlated with serum S100B levels. Additionally, we investigated whether serum S100B levels can be used to predict 1-year mortality in cirrhotic patients. In total, 95 cirrhotic patients were consecutively enrolled and divided into the following three groups: (i) without any types of HEs; (ii) with MHE; and (iii) with overt HE. The diagnosis of MHE was made by the Mini-Mental State Examination (MMSE) and Psychometric Hepatic Encephalopathy Score (PHES). Among the three groups, there were no significant differences in serum S100B levels regardless of HE severity. The clinical parameters correlated with serum S100B levels were age, serum bilirubin, and creatinine levels. The Model for End-Stage Liver Disease (MELD) score showed a significant positive correlation with serum S100B levels. The relationship between serum S100B levels and MELD score was maintained in 48 patients without any type of HE. Additionally, hyperammonemia, low cholesterol levels, and the combination of serum S100B levels ≥ 35 pg/mL with MELD score ≥ 13 were factors for predicting 1- year mortality. In conclusion, serum S100B level was not useful for differentiating the severity of HE. However, we found that serum S100B levels can be affected by age, serum bilirubin, and creatinine in cirrhotic patients and are associated with MELD scores. Additionally, serum S100B levels showed the possibility of predicting 1-year mortality in cirrhotic patients. These findings suggest that serum S100B levels may reflect liver dysfunction and prognosis in liver disease.

Molecular diagnostics in neurotrauma: Are there reliable biomarkers and effective methods for their detection?

To date, a large number of studies are being carried out in the field of neurotrauma, researchers not only establish the molecular mechanisms of the course of the disorders, but are also involved in the search for effective biomarkers for early prediction of the outcome and therapeutic intervention. Particular attention is paid to traumatic brain injury and spinal cord injury, due to the complex cascade of reactions in primary and secondary injury that affect pathophysiological processes and regenerative potential of the central nervous system. Despite a wide range of methods available methods to study biomarkers that correlate with the severity and degree of recovery in traumatic brain injury and spinal cord injury, development of reliable test systems for clinical use continues. In this review, we evaluate the results of recent studies looking for various molecules acting as biomarkers in the abovementioned neurotrauma. We also summarize the current knowledge of new methods for studying biological molecules, analyzing their sensitivity and limitations, as well as reproducibility of results. In this review, we also highlight the importance of developing reliable and reproducible protocols to identify diagnostic and prognostic biomolecules.

A Pathophysiological Approach To Current Biomarkers

Biomarkers are necessary for screening and diagnosing numerous diseases, predicting the prognosis of patients, and following-up treatment and the course of the patient. Everyday new biomarkers are being used in clinics for these purposes. This section will discuss the physiological roles of the various current biomarkers in a healthy person and the pathophysiological mechanisms underlying the release of these biomarkers. This chapter aims to gain a new perspective for evaluating and interpreting the most current biomarkers.

Sensitivity of serum S100B protein as a disease activity marker in Egyptian patients with vitiligo (case-control study)

BACKGROUND

Vitiligo is a depigmented skin disease. S100B is a damage-associated molecular pattern protein proposed as a marker of melanocyte cytotoxicity.

AIM

To detect the sensitivity of serum levels of S100B as a disease activity marker in vitiligo patients.

METHODS

Four patient groups of both sexes: twenty segmental vitiligo, twenty non-segmental active vitiligo patients, twenty non-segmental stable vitiligo patients and thirty healthy controls age and sex-matched, patients were subjected to vitiligo disease activity score (VIDA score) and Vitiligo Extent Tensity Index (VETI) score.

RESULTS

An increased level of S100B was observed in patients with vitiligo compared to control, there was statistically significant increase in its level in non- segmental-active than non-segmental stable and segmental-stable. Roc analysis for S100B to predict cases vs control was confirmed by getting cut off point 80.2 pg/ml, with high sensitivity 96.67 and high specificity 96.67. Roc analysis for S100B to predict non-segmental-active versus segmental and non-segmental was also confirmed by getting cut off point 118.3 pg/ml, with sensitivity 80.0 and specificity 77.50.

CONCLUSION

S100B can be used as indicators for disease activity with high sensitivity and specificity in Egyptian vitiligo patients.

Impact of medium cut-off membranes on S100A12 and soluble receptor for advanced glycation end products

INTRODUCTION

Of the most remarkable molecules associated with atherosclerosis and the cardiovascular outcome are S100A12 (10,379.5 Da) and soluble receptor for advanced glycation end products (sRAGE-42,803 Da) in the hemodialysis (HD) population. We designed a study investigating the effects of the medium cut-off (MCO) dialyzers focusing on S100A12 and sRAGE in HD patients compared with low-flux and high-flux dialyzers.

METHODS

This single-site, prospective, observational study comprises age and sex-matched HD groups (low-flux, high-flux, and MCO). Blood samples were drawn at baseline (predialysis and postdialysis) and the sixth month (predialysis).

RESULTS

Groups had similar demographic features and laboratory parameters. Baseline S100A12 levels of the groups were similar [34.3 (±66.5), 30.9 (±42.7), and 40.6 (±29.6); p = 0.13]. Compared to their baseline, the sixth-month S100A12 levels were constant in low-flux and high-flux group and significantly lower in MCO group (p = 0.16, p = 0.33, and p = 0.004). Baseline sRAGE levels of the groups were similar at baseline [2.8 (±0.8), 2.7 (±0.6), and 2.6 (±0.7); p = 0.65], and the sixth-month [2.9 (±0.5), 2.4 (±0.7), and 2.4 (±0.8); p = 0.24]. sRAGE levels remained constant in all groups [p = 0.84, p = 0.13, and p = 0.39]. S100A12/sRAGE ratio at baseline and sixth month was constant in low-flux [22.3 (±63.7) and 18.1 (±24.8); p = 0.17] and high-flux groups [11.9 (±15.3) and 13.1 (±5.8); p = 0.26], the ratio decreased significantly in MCO group [16.5 (±11.6) to 7.8 (±5.5); p = 0.03].

CONCLUSION

Our study suggests that prolonged use of MCO dialyzers is associated with better S100A12 and sRAGE levels. Long-term studies with larger samples are needed to understand the effects of a better S100A12-sRAGE profile provided by MCO dialyzers on HD patients' cardiovascular outcomes.

PACE4-altCT isoform of proprotein convertase PACE4 as tissue and plasmatic biomarker for prostate cancer

The proprotein convertase PACE4 has demonstrated value as a viable therapeutic target in prostate cancer (PCa). A novel isoform named PACE4-altCT, which arises in neoplastic lesions, plays an important role in tumor progression and has been validated as a pharmacological target. With the discovery of its overexpression in PCa and the alternative splicing of its pre-RNA to generate an oncogenic C-terminally modified isoform named PACE4-altCT, understanding and validating its value as a potential biomarker is of great interest either from prognostic or targeted therapy intervention. Expression of ERG in LNCaP cells was used to investigate the relationship between ERG expression occurring in PCa cells and PACE4-altCT expression by Western blot and qPCR. Using immunohistochemistry, the expression levels of PACE4 isoforms in patient tissues were investigated and correlated with ERG tumor status and Gleason score. An ELISA method was developed using affinity purified recombinant protein and used for quantitative analysis of plasma concentrations of PACE4-altCT and used for correlation. In contrast with the consensual isoform, PACE4-altCT was only strongly overexpressed in prostate cancer patients, correlated with ERG expression levels. Despite its intracellular retention PACE4-altCT could be detected in the plasma of most patients with prostate cancer, whereas it was only found at low levels in normal patients whereas total plasmatic PACE4 levels did not vary significantly between groups. Our study demonstrates that PACE4-altCT is strongly overexpressed in prostate cancer using both immunohistochemical and ELISA techniques and may have some interesting potential as a biomarker.

Serum Biomarkers of Regeneration and Plasticity are Associated with Functional Outcome in Pediatric Neurocritical Illness: An Exploratory Study

BACKGROUND/OBJECTIVE

Pediatric neurocritical care survivorship is frequently accompanied by functional impairments. Lack of prognostic biomarkers is a barrier to early identification and management of impairment. We explored the association between blood biomarkers and functional impairment in children with acute acquired brain injury.

METHODS

This study is a secondary analysis of a randomized control trial evaluating early versus usual care rehabilitation in the pediatric intensive care unit (PICU). Forty-four children (17 [39%] female, median age 11 [interquartile range 6-13] years) with acute acquired brain injury admitted to the PICU were studied. A single center obtained serum samples on admission days 0, 1, 3, 5, and the day closest to hospital discharge. Biomarkers relevant to brain injury (neuron specific enolase [NSE], S100b), inflammation (interleukin [IL-6], C-reactive protein), and regeneration (brain-derived neurotrophic factor [BDNF], vascular endothelial growth factor [VEGF]) were collected. Biomarkers were analyzed using a Luminex® bioassay. Functional status scale (FSS) scores were abstracted from the medical record. New functional impairment was defined as a (worse) FSS score at hospital discharge compared to pre-PICU (baseline). Individual biomarker fluorescence index (FI) values for each sample collection day were correlated with new functional impairment using Spearman rank correlation coefficient (ρ). Trends in repeated measures of biomarker FI over time were explored graphically, and the association between repeated measures of biomarker FI and new functional impairment was analyzed using covariate adjusted linear mixed-effect models.

RESULTS

Functional impairment was inversely correlated with markers of regeneration and plasticity including BDNF at day 3 (ρ =  - 0.404, p = .015), day 5 (ρ =  - 0.549, p = 0.005) and hospital discharge (ρ =  - 0.420, p = 0.026) and VEGF at day 1 (ρ =  - 0.282, p = 0.008) and hospital discharge (ρ =  - 0.378, p = 0.047), such that lower levels of both markers at each time point were associated with greater impairment. Similarly, repeated measures of BDNF and VEGF were inversely correlated with new functional impairment (B =  - 0.001, p = 0.001 and B =  - 0.001, p = 0.003, respectively). NSE, a biomarker of acute brain injury, showed a positive correlation between day 0 levels and new functional impairment (ρ = 0.320, p = 0.044).

CONCLUSIONS

Blood-based biomarkers of regeneration and plasticity may hold prognostic utility for functional impairment among pediatric patients with neurocritical illness and warrant further investigation.

Blood biomarkers for mild traumatic brain injury: a selective review of unresolved issues

Background

The use of blood biomarkers after mild traumatic brain injury (mTBI) has been widely studied. We have identified eight unresolved issues related to the use of five commonly investigated blood biomarkers: neurofilament light chain, ubiquitin carboxy-terminal hydrolase-L1, tau, S100B, and glial acidic fibrillary protein. We conducted a focused literature review of unresolved issues in three areas: mode of entry into and exit from the blood, kinetics of blood biomarkers in the blood, and predictive capacity of the blood biomarkers after mTBI.

Findings

Although a disruption of the blood brain barrier has been demonstrated in mild and severe traumatic brain injury, biomarkers can enter the blood through pathways that do not require a breach in this barrier. A definitive accounting for the pathways that biomarkers follow from the brain to the blood after mTBI has not been performed. Although preliminary investigations of blood biomarkers kinetics after TBI are available, our current knowledge is incomplete and definitive studies are needed. Optimal sampling times for biomarkers after mTBI have not been established. Kinetic models of blood biomarkers can be informative, but more precise estimates of kinetic parameters are needed. Confounding factors for blood biomarker levels have been identified, but corrections for these factors are not routinely made. Little evidence has emerged to date to suggest that blood biomarker levels correlate with clinical measures of mTBI severity. The significance of elevated biomarker levels thirty or more days following mTBI is uncertain. Blood biomarkers have shown a modest but not definitive ability to distinguish concussed from non-concussed subjects, to detect sub-concussive hits to the head, and to predict recovery from mTBI. Blood biomarkers have performed best at distinguishing CT scan positive from CT scan negative subjects after mTBI.

A Kinetic Model for Blood Biomarker Levels After Mild Traumatic Brain Injury

Traumatic brain injury (TBI) imposes a significant economic and social burden. The diagnosis and prognosis of mild TBI, also called concussion, is challenging. Concussions are common among contact sport athletes. After a blow to the head, it is often difficult to determine who has had a concussion, who should be withheld from play, if a concussed athlete is ready to return to the field, and which concussed athlete will develop a post-concussion syndrome. Biomarkers can be detected in the cerebrospinal fluid and blood after traumatic brain injury and their levels may have prognostic value. Despite significant investigation, questions remain as to the trajectories of blood biomarker levels over time after mild TBI. Modeling the kinetic behavior of these biomarkers could be informative. We propose a one-compartment kinetic model for S100B, UCH-L1, NF-L, GFAP, and tau biomarker levels after mild TBI based on accepted pharmacokinetic models for oral drug absorption. We approximated model parameters using previously published studies. Since parameter estimates were approximate, we did uncertainty and sensitivity analyses. Using estimated kinetic parameters for each biomarker, we applied the model to an available post-concussion biomarker dataset of UCH-L1, GFAP, tau, and NF-L biomarkers levels. We have demonstrated the feasibility of modeling blood biomarker levels after mild TBI with a one compartment kinetic model. More work is needed to better establish model parameters and to understand the implications of the model for diagnostic use of these blood biomarkers for mild TBI.

Impact of Circulating and Tissue Biomarkers in Adjuvant and Neoadjuvant Therapy for High-Risk Melanoma: Ready for Prime Time?

The prognosis of patients with metastatic melanoma has substantially improved over the last years with the advent of novel treatment strategies, mainly immune checkpoint inhibitors and BRAF and MEK inhibitors. Given the survival benefit provided in the metastatic setting and the evidence from prospective clinical trials in the early stages, these drugs have been introduced as adjuvant therapies for high-risk resected stage III disease. Several studies have also investigated immune checkpoint inhibitors, as well as BRAF and MEK inhibitors, for neoadjuvant treatment of high-risk stage III melanoma, with preliminary evidence suggesting this could be a very promising approach in this setting. However, even with new strategies, the risk of disease recurrence varies widely among stage III patients, and no available biomarkers for predicting disease recurrence have been established to date. Improved risk stratification is particularly relevant in this setting to avoid unnecessary treatment for patients who have minimum risk of disease recurrence and to reduce toxicities and costs. Research for predictive and prognostic biomarkers in this setting is ongoing to potentially shed light on the complex interplay between the tumor and the host immune system, and to further personalize treatment. This review provides an insight into available data on circulating and tissue biomarkers, including the tumor microenvironment and associated gene signatures, and their predictive and prognostic role during neoadjuvant and adjuvant treatment for cutaneous high-risk melanoma patients.

Serum level of S100B in vitiligo patients: Is it a marker of disease activity?

BACKGROUND

Vitiligo is a chronic depigmentary skin disorder, characterised clinically by the development of white macules and or patches caused by loss of epidermal melanocytes. S100B is a dual function protein released from epidermal melanocytes in response to injury. It considered a possible marker of disease activity in both malignant melanoma and vitiligo.

AIM OF THE STUDY

To estimate the serum level of S100B level in vitiligo patients and correlate its level with disease activity and various disease parameters.

PATIENTS AND METHODS

Sixty vitiligo patients and 60 healthy volunteers as controls were included in the study. Vitiligo Area Severity Index (VASI) and Vitiligo Disease Activity (VIDA) scores were estimated for each patient. Quantitative assessment of S100B level using ELISA technique was done for all participants.

RESULTS

S100B level was significantly correlated with the presence of vitiligo (P = 0.01), while it showed no correlation with the disease activity using VASI or VIDA scores. As regards the receiver operating characteristic (ROC) curve analysis of S100B for diagnosis and discrimination of vitiligo, serum S100B showed area under the curve (AUC) of 0.781 with 73.3% sensitivity and 80% specificity.

CONCLUSION

The serum level of S100B was related to the presence of vitiligo, but its level did not show any relation to the disease activity using either VASI and VIDA scores or various disease parameters.

Monthly changes in serum levels of S100B protein as a predictor of metastasis development in high-risk melanoma patients

BACKGROUND

The role of S100B protein in detecting early melanoma relapses is controversial, since most metastasis occur within normal values of S100B.

OBJECTIVE

The aim of this study was to assess the performance of S100B in detecting early disease progression in high-risk melanoma patients.

METHODS

Retrospective cohort study including patients with an initial diagnosis of stage IIB, IIC and III melanoma between January 2003 and July 2013. All patients were followed up in accordance with an intensive protocol based on imaging studies and serum S100B levels every 3-6 months. We compared two methods to evaluate changes in S100B. The classic method referring to a single determination of S100B above the cut-off level at the time of metastasis, which was evaluated in all patients. And a new method based on monthly changes of S100, which was used in the setting of patients with S100B levels within the normal range.

RESULTS

Overall, 289 of patients were followed up for 44 months (IQR 17-73) and 45% developed metastases. During the study period, 129 patients relapsed of which 46 (35.7%) present elevated values of S100B at the time of relapse. The classic method had a sensitivity and specificity of S100B protein of 35.7% and 92.5%, respectively. Furthermore, for the patients that relapsed with normal values of S100B, the new method was applied and showed a sensitivity and specificity of 41.1% and 92.4%, respectively, allowing to detect additional relapses that were missing by the classic method.

CONCLUSION

During follow-up of high-risk melanoma patients, rising serum S100B values within the normal range can be an important clue to disease progression.

Correlative Monitoring of Immune Activation and Tissue Damage in Malignant Melanoma-An Algorithm for Identification of Tolerance Breakage During Immune Checkpoint Inhibitor Therapy of Cancer

We describe an innovative approach for identification of tolerance breakage during immune checkpoint inhibitor therapy in malignant melanoma. Checkpoint inhibitor therapy enhances the immunologic clearance of cancer by suppressing pathways which induce immune suppression and tolerance. We posit that by analyzing temporal correlations of key markers of immune activation and tissue damage it would be possible to detect the onset of anticancer immune reaction as well as of immunologic adverse effects which might become crucial for optimization as well as safety of immune checkpoint inhibitor treatment. We analyzed time courses of routine laboratory values of serum tumor markers as well as of markers of immune activation in 17 patients with metastasized malignant melanoma receiving checkpoint inhibition and weekly laboratory controls. A parallel serum level increase of interleukin-6 and the tumor marker S100B could be identified in 13 patients, suggesting that the onset of tolerance breakage under checkpoint inhibition may be identified and measured. Immune-related adverse events in the patients were also accompanied by a peak of IL-6. In six patients, the onset of a putative anticancer immune reaction and the beginning of immunologic adverse events occurred in the same treatment cycle; in six patients the immunologic adverse reactions took place in separate cycles.

Biomarkers Predictive of Survival and Response to Immune Checkpoint Inhibitors in Melanoma

Immunotherapy has revolutionized the treatment of melanoma. Targeting of the immune checkpoints cytotoxic T-lymphocyte-associated protein 4 and programmed cell death protein 1 has led to improved survival in a subset of patients. Unfortunately, the use of immune checkpoint inhibitors is associated with significant side effects and many patients do not respond to treatment. Thus, there is an urgent need both for prognostic biomarkers to estimate risk and for predictive biomarkers to determine which patients are likely to respond to therapy. In this review, prognostic and predictive biomarkers that are an active area of research are outlined. Of note, certain transcriptomic signatures are already used in the clinic, albeit not routinely, to prognosticate patients. In the predictive setting, programmed cell death protein ligand 1 expression has been shown to correlate with benefit but is not precise enough to be used as an exclusionary biomarker. Future investigation will need to focus on biomarkers that are easily reproducible, cost effective, and accurate. The use of readily available clinical material, such as serum or hematoxylin and eosin-stained images, may offer one such path forward.

Tumor microenvironment-derived S100A8/A9 is a novel prognostic biomarker for advanced melanoma patients and during immunotherapy with anti-PD-1 antibodies

BACKGROUND

Predicting metastasis in melanoma patients is important for disease management and could help to identify those who might benefit from adjuvant treatment. The aim of this study was to investigate whether the tumor microenvironment-derived protein S100A8/A9 qualifies as prognostic marker for melanoma patients, also in the setting of immunotherapy.

METHODS

S100A8/A9 gene and protein expression were analyzed on melanocytic nevi, primary melanomas and metastases using a cDNA library and three independent tissue-microarrays (TMA). Serum levels of S100A8/A9 were measured using a specific ELISA in two independent cohorts of 354 stage III and stage IV melanoma patients as well as in two independent cohorts of patients treated with the PD-1 antibody pembrolizumab.

RESULTS

cDNA analysis revealed an upregulation of S100A8 and S100A9 gene expression in melanoma metastases compared to primary melanomas. Significantly higher numbers of infiltrating S100A8/A9 positive cells were found in tissue samples of metastasizing primary melanomas compared to non-metastasizing melanomas (P < .0001) and in melanomas of short-term survivors compared to long-term survivors (P < .0001). Serum S100A8/A9 levels > 5.5 mg/l were associated with impaired overall survival in two independent cohorts (both P < .0001). Importantly, patients with serum elevated S100A8/A9 treated with pembrolizumab showed significantly impaired survival compared to patients with lower S100A8/A9 levels (cohort 1: P = .0051; cohort 2: P < .0001).

CONCLUSIONS

The tumor microenvironment-associated protein S100A8/A9 serves as a novel prognostic marker for metastasis and survival of metastatic melanoma patients and predicts response to immunotherapy with pembrolizumab. These data underscore the significance of tumor microenvironment-derived factors as suitable biomarkers for melanoma.

Serum S100B Levels in Melanoma

Malignant melanoma is a cancer with increasing incidence worldwide with relevant socioeconomic impact. Despite progress in prevention and early detection, it is one of the most lethal forms of skin cancer. Therefore it is urgent need to identify suitable biomarkers in order to improve early diagnosis, precise staging, and prognosis, as well as for therapy selection and monitoring. In this book chapter, we are focusing on S100B and discuss its clinical relevance in melanoma.

Multifarious diagnostic possibilities of the S100 protein family: predominantly in pediatrics and neonatology

BACKGROUND

Numerous articles related to S100 proteins have been recently published. This review aims to introduce this large protein family and its importance in the diagnostics of many pathological conditions in children and adults.

DATA SOURCES

Based on original publications found in database systems, we summarize the current knowledge about the S100 protein group and highlight the most important proteins with focus on pediatric use.

RESULTS

The S100 family is composed of Ca²⁺ and Zn²⁺ binding proteins, which are present only in vertebrates. Some of these proteins can be used as diagnostic markers in cardiology (S100A1, S100A12), oncology (S100A2, S100A5, S100A6, S100A14, S100A16, S100P, S100B), neurology (S100B), rheumatology (S100A8/A9, S100A4, S100A6, and S100A12), nephrology and infections (S100A8, S100A9, S100A8/A9, S100A12). The most useful S100 proteins in pediatrics are S100A8, S100A9, heterodimers S100A8/A9, S100B and S100A12.

CONCLUSIONS

The S100 family members are promising biomarkers and provide numerous possibilities for implementation into clinical practice to optimize the differential diagnostic process.

Emerging Biomarkers in Cutaneous Melanoma

Earlier identification of aggressive melanoma remains a goal in the field of melanoma research. With new targeted and immune therapies that have revolutionized the care of patients with melanoma, the ability to predict progression and monitor or predict response to therapy has become the new focus of research into biomarkers in melanoma. In this review, promising biomarkers are highlighted. These biomarkers have been used to diagnose melanoma as well as predict progression to advanced disease and response to therapy. The biomarkers take various forms, including protein expression at the level of tissue, genetic mutations of cancer cells, and detection of circulating DNA. First, a brief description is provided about the conventional tissue markers used to stage melanoma, including tumor depth. Next, protein biomarkers, which provide both diagnostic and prognostic information, are described. This is followed by a discussion of important genetic mutations, microRNA, and epigenetic modifications that can provide therapeutic and prognostic material. Finally, emerging serologic biomarkers are reviewed, including circulating melanoma cells and exosomes. Overall the goal is to identify biomarkers that aid in the earlier identification and improved treatment of aggressive melanoma.

Anorectal mucosal melanoma

Anorectal melanoma is an uncommon and aggressive mucosal melanocytic malignancy. Due to its rarity, the pre-operative diagnosis remains difficult. The first symptoms are non-specific such as anal bleeding, anal mass or pain. Although anorectal melanoma carries a poor prognosis; optimal therapeutics strategies are unclear. Surgical resection remains the mainstay of treatment. The optimal surgical procedure for primary tumours is controversial and can vary from wide local excision or endoscopic mucosal resection (EMR) to an abdomino-perineal resection. A high degree of uncertainly exists regarding the benefit of radiation therapy or chemotherapy. The treatment of advanced melanoma is evolving rapidly with better understanding of the disease biology and immunology. Considerable effort has been devoted to the identification of molecular determinants of response to target therapies and immunotherapy.

Biomarkers of Cerebral Injury and Inflammation in Pediatric Tuberculous Meningitis

Background

Tuberculous meningitis (TBM) leads to death or disability in half the affected individuals. Tools to assess severity and predict outcome are lacking. Neurospecific biomarkers could serve as markers of the severity and evolution of brain injury, but have not been widely explored in TBM. We examined biomarkers of neurological injury (neuromarkers) and inflammation in pediatric TBM and their association with outcome.

Methods

Blood and cerebrospinal fluid (CSF) of children with TBM and hydrocephalus taken on admission and over 3 weeks were analyzed for the neuromarkers S100B, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP), in addition to multiple inflammatory markers. Results were compared with 2 control groups: patients with (1) a fatty filum (abnormal filum terminale of the spinal cord); and (2) pulmonary tuberculosis (PTB). Imaging was conducted on admission and at 3 weeks. Outcome was assessed at 6 months.

Results

Data were collected from 44 patients with TBM (cases; median age, 3.3 [min-max 0.3-13.1] years), 11 fatty filum controls (median age, 2.8 [min-max 0.8-8] years) and 9 PTB controls (median age, 3.7 [min-max 1.3-11.8] years). Seven cases (16%) died and 16 (36%) had disabilities. Neuromarkers and inflammatory markers were elevated in CSF on admission and for up to 3 weeks, but not in serum. Initial and highest concentrations in week 1 of S100B and NSE were associated with poor outcome, as were highest concentration overall and an increasing profile over time in S100B, NSE, and GFAP. Combined neuromarker concentrations increased over time in patients who died, whereas inflammatory markers decreased. Cerebral infarcts were associated with highest overall neuromarker concentrations and an increasing profile over time. Tuberculomas were associated with elevated interleukin (IL) 12p40, interferon-inducible protein 10, and monocyte chemoattractant protein 1 concentrations, whereas infarcts were associated with elevated tumor necrosis factor α, macrophage inflammatory protein 1α, IL-6, and IL-8.

Conclusions

CSF neuromarkers are promising biomarkers of injury severity and are predictive of mortality. An increasing trend suggested ongoing brain injury, even though markers of inflammation declined with treatment. These findings could offer novel insight into the pathophysiology of TBM.

The association between FABP7 serum levels with survival and neurological complications in acetaminophen-induced acute liver failure: a nested case-control study

BACKGROUND

Acetaminophen (APAP)-induced acute liver failure (ALF) is associated with significant mortality due to intracranial hypertension (ICH), a result of cerebral edema (CE) and astrocyte swelling. Brain-type fatty acid-binding protein (FABP7) is a small (15 kDa) cytoplasmic protein abundantly expressed in astrocytes. The aim of this study was to determine whether serum FABP7 levels early (day 1) or late (days 3-5) level were associated with 21-day mortality and/or the presence of ICH/CE in APAP-ALF patients.

METHODS

Serum samples from 198 APAP-ALF patients (nested case-control study with 99 survivors and 99 non-survivors) were analyzed by ELISA methods and assessed with clinical data from the US Acute Liver Failure Study Group (ALFSG) Registry (1998-2014).

RESULTS

APAP-ALF survivors had significantly lower serum FABP7 levels on admission (147.9 vs. 316.5 ng/ml, p = 0.0002) and late (87.3 vs. 286.2 ng/ml, p < 0.0001) compared with non-survivors. However, a significant association between 21-day mortality and increased serum FABP7 early [log FABP7 odds ratio (OR) 1.16, p = 0.32] and late (log FABP7 ~ OR 1.34, p = 0.21) was not detected after adjusting for significant covariates (MELD, vasopressor use). Areas under the receiver-operating curve for early and late multivariable models were 0.760 and 0.892, respectively. In a second analysis, patients were grouped based on the presence (n = 46) or absence (n = 104) of ICH/CE. A significant difference in FABP7 levels between patients with or without ICH/CE at early (259.7 vs. 228.2 ng/ml, p = 0.61) and late (223.8 vs. 192.0 ng/ml, p = 0.19) time points was not identified.

CONCLUSION

Serum FABP7 levels were significantly elevated at early and late time points in APAP-ALF non-survivors compared to survivors. However, significant differences in FABP7 levels by 21-day mortality were not ascertained after adjusting for significant covariates (reflecting severity of illness). Our study suggests that FABP7 may not discriminate between patients with or without intracranial complications.

Systemic impact on secondary brain aggravation due to ischemia/reperfusion injury in post-cardiac arrest syndrome: a prospective observational study using high-mobility group box 1 protein

BACKGROUND

Ischemia/reperfusion injury (I/R) is an important pathophysiology of post-cardiac arrest syndrome (PCAS) against multiple organ dysfunction and mortality. The inflammatory response in PCAS causes systemic I/R. The purpose of this study was to demonstrate the pathophysiology of systemic I/R for secondary brain damage using the biomarkers high-mobility group box 1 (HMGB1), neuron-specific enolase (NSE), and interleukin-6 (IL-6).

METHODS

This study was designed as a single-institution prospective observational study. Subjects were observed for 90 days, and neurological outcome was classified according to the Glasgow-Pittsburgh Cerebral Performance Categories Scale (CPC). Serum HMGB1, NSE, and IL-6 were evaluated for variability, correlation with each biomarker, or the Sequential Organ Function Assessment (SOFA) score and CPC at return of spontaneous circulation at 0, 24, 48, and 168 h.

RESULTS

A total of 128 patients were enrolled in this study. Initial HMGB1 correlated with CPC (ρ = 0.27, p = 0.036) and SOFA score (ρ = 0.33, p < 0.001). The early phase of HMGB1 (0-24 h), all phases of IL-6, and the delayed phase of NSE (24-168 h) manifested poor neurological outcome. HMGB1 showed a significant correlation with NSE (ρ = 0.29, p = 0.002 at 0 h; ρ = 0.42, p < 0.001 at 24 h) and IL-6 (ρ = 0.36, p < 0.001 at 24 h).

CONCLUSIONS

Serum HMGB1 for first 24 h after cardiac arrest was significantly correlated with SOFA score, NSE, and IL-6. This result suggests that systemic I/R may contribute to secondary brain aggravation. It is expected that research on HMGB1 focused on systemic I/R will help prevent aggravating neurological outcomes.

S100B: Correlation with Active Vitiligo Depigmentation

Vitiligo, the most common depigmenting disorder, is caused by immune destruction of melanocytes by cytotoxic CD8⁺ T cells. One weakness in vitiligo management is the lack of an assessment method for active depigmentation. Beginning with reports about increased S100B levels in different inflammatory and tissue damage processes, Speeckaert et al. explored correlations between the S100B dynamics and vitiligo activity, identifying high circulating S100B levels in patients with active depigmentation which were strongly correlated with the extent of affected skin surface. These authors have proposed S100B as a potential disease activity marker in vitiligo.

The Insertion of Electrodes in the Brain for Electrophysiological Recording or Chronic Stimulation Is Not Associated With Any Biochemically Detectable Neuronal Injury

OBJECTIVE

The aim of this study was to evaluate the degree of brain tissue injury that could be potentially induced by the introduction of a) microrecording electrodes, b) macrostimulation electrodes, or c) chronic stimulation electrodes. We aimed to evaluate whether the use of five simultaneous microrecording tracks is associated with any brain injury not detectable by conventional imaging such as CT or MRI.

MATERIALS AND METHODS

The study included 61 patients who underwent surgery for implantation of 121 DBS leads. In all cases, five simultaneous tracts were utilized for microelectrode recordings. All patients underwent measurements of serum S-100b at specific time points as follows: a) prior to the operation, and b) intraoperatively at specific stages of the procedure: 1) after opening the burr hole, 2) after the insertion of microrecording electrodes, 3) during macrostimulation, 4) at the end of the operation, and 5) on the first postoperative day.

RESULTS

The levels of serum S-100B protein remained within the normal range during the entire period of investigation in all patients with the exception of two cases. In both patients, the procedure was complicated by intraparenchymal hemorrhage visible in neuro-imaging. The first patient developed a small intraparenchymal hemorrhage, visible on the postoperative MRI, with no neurological deficit. The second patient experienced a focal epileptic seizure after the insertion of the right DBS chronic lead and the postoperative CT scan revealed a right frontal lobe hemorrhage.

CONCLUSION

These results strongly indicate that the insertion of either multiple recording electrodes or the implantation of chronic electrodes in DBS does not increase the risk of brain hemorrhage or of other intracranial complications, and furthermore it does not cause any biochemically detectable brain tissue damage.

S100B Is a Potential Disease Activity Marker in Nonsegmental Vitiligo

Vitiligo is a chronic skin condition characterized by progressive depigmentation of the skin. S100B is a damage-associated molecular pattern protein expressed in melanocytes that has been proposed as a marker of melanocyte cytotoxicity. Although the use of S100B as a biomarker in melanoma is well established, to our knowledge its association with vitiligo activity has not yet been investigated. Here, we show that S100B serum levels were significantly increased in patients with active nonsegmental vitiligo and strongly correlated with the affected body surface area. Prospective follow-up showed a predictive value of serum S100B levels on disease progression. In vitro experiments using repeated freeze-thaw procedures showed an intracellular up-regulation of S100B in normal and vitiligo melanocytes before an extensive release in the environment. This phenomenon may explain the increased S100B serum values in the active phase of vitiligo. In a monobenzone-induced vitiligo mouse model we could show the potential of S100B inhibition as a therapeutic strategy in vitiligo. In conclusion, this report shows the possible use of S100B as a biomarker for disease activity in vitiligo. Our data suggest that this damage-associated molecular pattern protein could play a substantial role in the pathogenesis of vitiligo and may be a potential new target for treatment.

A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury

Background

In order to improve injury assessment of brain injuries, protein markers of pathophysiological processes and tissue fate have been introduced in the clinic. The most studied protein “biomarker” of cerebral damage in traumatic brain injury (TBI) is the protein S100B. The aim of this narrative review is to thoroughly analyze the properties and capabilities of this biomarker with focus on clinical utility in the assessment of patients suffering from TBI.

Results

S100B has successfully been implemented in the clinic regionally (1) to screen mild TBI patients evaluating the need to perform a head computerized tomography, (2) to predict outcome in moderate-to-severe TBI patients, (3) to detect secondary injury development in brain-injured patients and (4) to evaluate treatment efficacy. The potential opportunities and pitfalls of S100B in the different areas usually refer to its specificity and sensitivity to detect and assess intracranial injury.

Conclusion

Given some shortcomings that should be realized, S100B can be used as a versatile screening, monitoring and prediction tool in the management of TBI patients.

A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury

BACKGROUND

In order to improve injury assessment of brain injuries, protein markers of pathophysiological processes and tissue fate have been introduced in the clinic. The most studied protein "biomarker" of cerebral damage in traumatic brain injury (TBI) is the protein S100B. The aim of this narrative review is to thoroughly analyze the properties and capabilities of this biomarker with focus on clinical utility in the assessment of patients suffering from TBI.

RESULTS

S100B has successfully been implemented in the clinic regionally (1) to screen mild TBI patients evaluating the need to perform a head computerized tomography, (2) to predict outcome in moderate-to-severe TBI patients, (3) to detect secondary injury development in brain-injured patients and (4) to evaluate treatment efficacy. The potential opportunities and pitfalls of S100B in the different areas usually refer to its specificity and sensitivity to detect and assess intracranial injury.

CONCLUSION

Given some shortcomings that should be realized, S100B can be used as a versatile screening, monitoring and prediction tool in the management of TBI patients.

Improving the clinical management of traumatic brain injury through the pharmacokinetic modeling of peripheral blood biomarkers

Background

Blood biomarkers of neurovascular damage are used clinically to diagnose the presence severity or absence of neurological diseases, but data interpretation is confounded by a limited understanding of their dependence on variables other than the disease condition itself. These include half-life in blood, molecular weight, and marker-specific biophysical properties, as well as the effects of glomerular filtration, age, gender, and ethnicity. To study these factors, and to provide a method for markers’ analyses, we developed a kinetic model that allows the integrated interpretation of these properties.

Methods

The pharmacokinetic behaviors of S100B (monomer and homodimer), Glial Fibrillary Acidic Protein and Ubiquitin C-Terminal Hydrolase L1 were modeled using relevant chemical and physical properties; modeling results were validated by comparison with data obtained from healthy subjects or individuals affected by neurological diseases. Brain imaging data were used to model passage of biomarkers across the blood–brain barrier.

Results

Our results show the following: (1) changes in biomarker serum levels due to age or disease progression are accounted for by differences in kidney filtration; (2) a significant change in the brain-to-blood volumetric ratio, which is characteristic of infant and adult development, contributes to variation in blood concentration of biomarkers; (3) the effects of extracranial contribution at steady-state are predicted in our model to be less important than suspected, while the contribution of blood–brain barrier disruption is confirmed as a significant factor in controlling markers’ appearance in blood, where the biomarkers are typically detected; (4) the contribution of skin to the marker S100B blood levels depends on a direct correlation with pigmentation and not ethnicity; the contribution of extracranial sources for other markers requires further investigation.

Conclusions

We developed a multi-compartment, pharmacokinetic model that integrates the biophysical properties of a given brain molecule and predicts its time-dependent concentration in blood, for populations of varying physical and anatomical characteristics. This model emphasizes the importance of the blood–brain barrier as a gatekeeper for markers’ blood appearance and, ultimately, for rational clinical use of peripherally-detected brain protein.

Electronic supplementary material

The online version of this article (doi:10.1186/s12987-016-0045-y) contains supplementary material, which is available to authorized users.

Biomarker value and pitfalls of serum S100B in the follow-up of high-risk melanoma patients

BACKGROUND AND OBJECTIVES

Serum levels of S100B are standard in monitoring advanced malignant melanoma patients in order to discriminate progressive from non-progressive disease. False-positive results lead to distress among patients and increase the amount of cost-intensive diagnostics. We therefore analyzed reported comorbid diseases as putative sources of excessive S100B release.

PATIENTS AND METHODS

Here, we report a single-center experience on serum S100B levels in 2,664 blood samples from 1,113 stage IB to IV melanoma patients (AJCC) who presented for follow-up examinations over a period of 24 months.

RESULTS

Overall, 295 (11%) of patients developed disease progression. In patients with a high tumor load, the rate of false-negative results was 30/185 (16%). The rate of false-positive results was 247/2369 (12%). One hundred and six false-positive results (69%) compared to 46 true-positive results (31%) were found in patients with cardiovascular diseases such as arrhythmia (50/32) or previous myocardial infarction (22/14). Moreover, obesity (85/14), liver cirrhosis (31/10), migraine (18/2), chronic kidney disease (13/2), and previous stroke (11/1) were found to be associated with false-positive S100B levels.

CONCLUSIONS

Serum S100B is a useful quantitative biomarker in routine follow-up of high-risk melanoma patients. While false-negative results are frequent in patients with low tumor load, false-positive results are associated with several comorbid diseases and warrant careful reevaluation.

Kinetic modelling of serum S100b after traumatic brain injury

Background

An understanding of the kinetics of a biomarker is essential to its interpretation. Despite this, little kinetic modelling of blood biomarkers can be found in the literature. S100b is an astrocyte related marker of brain injury used primarily in traumatic brain injury (TBI). Serum levels are expected to be the net result of a multi-compartmental process. The optimal sample times for TBI prognostication, and to follow injury development, are unclear. The purpose of this study was to develop a kinetic model to characterise the temporal course of serum S100b concentration after primary traumatic brain injury.

Methods

Data of serial serum S100b samples from 154 traumatic brain injury patients in a neurointensive care unit were retrospectively analysed, including only patients without secondary peaks of this biomarker. Additionally, extra-cranial S100b can confound samples earlier than 12 h after trauma and were therefore excluded. A hierarchical, Bayesian gamma variate kinetic model was constructed and the parameters estimated by Markov chain Monte Carlo sampling.

Results

We demonstrated that S100b concentration changes dramatically over timescales that are clinically important for early prognostication with a peak at 27.2 h (95 % credible interval [25.6, 28.8]). Baseline S100b levels was found to be 0.11 μg/L (95 % credible interval [0.10, 0.12]).

Conclusions

Even small differences in injury to sample time may lead to marked changes in S100b during the first days after injury. This must be taken into account in interpretation. The model offers a way to predict the peak and trajectory of S100b from 12 h post trauma in TBI patients, and to identify deviations from this, possibly indicating a secondary event. Kinetic modelling, providing an equation for the peak and projection, may offer a way to reduce the ambiguity in interpretation of, in time, randomly sampled acute biomarkers and may be generally applicable to biomarkers with, in time, well defined hits.

Elevated Levels of SOX10 in Serum from Vitiligo and Melanoma Patients, Analyzed by Proximity Ligation Assay

Background

The diagnosis of malignant melanoma currently relies on clinical inspection of the skin surface and on the histopathological status of the excised tumor. The serum marker S100B is used for prognostic estimates at later stages of the disease, but analyses are marred by false positives and inadequate sensitivity in predicting relapsing disorder.

Objectives

To investigate SOX10 as a potential biomarker for melanoma and vitiligo.

Methods

In this study we have applied proximity ligation assay (PLA) to detect the transcription factor SOX10 as a possible serum marker for melanoma. We studied a cohort of 110 melanoma patients. We further investigated a second cohort of 85 patients with vitiligo, which is a disease that also affects melanocytes.

Results

The specificity of the SOX10 assay in serum was high, with only 1% of healthy blood donors being positive. In contrast, elevated serum SOX10 was found with high frequency among vitiligo and melanoma patients. In patients with metastases, lack of SOX10 detection was associated with treatment benefit. In two responding patients, a change from SOX10 positivity to undetectable levels was seen before the response was evident clinically.

Conclusions

We show for the first time that SOX10 represents a promising new serum melanoma marker for detection of early stage disease, complementing the established S100B marker. Our findings imply that SOX10 can be used to monitor responses to treatment and to assess if the treatment is of benefit at stages earlier than what is possible radiologically.

Serum protein S100 as marker of postoperative delirium after off-pump coronary artery bypass surgery: secondary analysis of two prospective randomized controlled trials

Background:

To investigate the predictive value of S100 (biochemical marker of neuroglial injury) for the occurrence of postoperative delirium (POD) in patients undergoing off-pump coronary artery bypass (OPCAB)-surgery.

Methods:

We enrolled 92 patients older than 18 years undergoing elective OPCAB-surgery. Serum-levels of S100 were determined at baseline (BL), end of surgery (EOS) and on the first postoperative day (PD1). Postoperatively, all-patients were evaluated daily until PD5 for the presence of POD using the confusion assessment method (CAM) or the confusion assessment method for the intensive care unit (CAM-ICU) for patients in the intensive care unit (ICU).

Results:

The overall incidence of POD was 21%. S100-values on PD1 significantly predicted the occurrence of POD during the later hospital stay [area under the curve (AUC)=0.724 (95% confidence interval (CI): 0.619–0.814); p=0.0001] with an optimal cut-off level of 123 pg mL

Conclusions:

S100-levels <123 pg mL

Circulating melanoma exosomes as diagnostic and prognosis biomarkers

BACKGROUND

Malignant melanoma is an aggressive cancer with an increasing incidence. Exosomes are actively secreted microvesicles, whose characteristics reflect those of the cell they are originated in. The aim of this study was to identify and evaluate the presence of the melanoma biomarkers MIA, S100B and tyrosinase-related protein 2 (TYRP2) in exosomes and their potential clinical utility.

METHODS

Serum samples were obtained from stage IV melanoma patients, melanoma-free patients and healthy controls. Exosomes were precipitated and TYRP2, MIA and S100B concentrations were quantified in serum, exosomes, and exosome-free serum.

RESULTS

Both MIA and S100B were detected in exosomes and correlated significantly with serum concentrations (S100B: r=0.968; MIA: r=0.799; p<0.001). MIA and S100B concentrations in exosomes were significantly higher in melanoma patients than in healthy controls and disease-free patients. However, TYRP2 concentrations in exosomes did not differ between these three groups. ROC curves analysis rendered AUCs for MIA of 0.883 (p<0.01) and of 0.840 for S100B (p<0.01). Patients with exosome MIA concentration higher than 2.5 μg/L showed shorter median survival related to those with lower level (4 versus 11 months; p<0.05).

CONCLUSIONS

MIA and S100B can be detected in exosomes from melanoma patients and their quantification presents diagnostic and prognostic utility.

Assessing bicycle-related trauma using the biomarker S100B reveals a correlation with total injury severity

PURPOSE

Worldwide, the use of bicycles, for both recreation and commuting, is increasing. S100B, a suggested protein biomarker for cerebral injury, has been shown to correlate to extracranial injury as well. Using serum levels of S100B, we aimed to investigate how S100B could be used when assessing injuries in patients suffering from bicycle trauma injury. As a secondary aim, we investigated how hospital length of stay and injury severity score (ISS) were correlated to S100B levels.

METHODS

We performed a retrospective, database study including all patients admitted for bicycle trauma to a level 1 trauma center over a four-year period with admission samples of S100B (n = 127). Computerized tomography (CT) scans were reviewed and remaining data were collected from case records. Univariate- and multivariate regression analyses, linear regressions and comparative statistics (Mann-Whitney) were used where appropriate.

RESULTS

Both intra- and extracranial injuries were correlated with S100B levels. Stockholm CT score presented the best correlation of an intracranial parameter with S100B levels (p < 0.0001), while the presences of extremity injury, thoracic injury, and non-cervical spinal injury were also significantly correlated (all p < 0.0001, respectively). A multivariate linear regression revealed that Stockholm CT score, non-cervical spinal injury, and abdominal injury all independently correlated with levels of S100B. Patients with a ISS > 15 had higher S100 levels than patients with ISS < 16 (p < 0.0001). Patients with extracranial, as well as intracranial- and extracranial injuries, had significantly higher levels of S100B than patients without injuries (p < 0.05 and p < 0.01, respectively). The admission serum levels of S100B (log, µg/L) were correlated with ISS (log) (r = 0.53) and length of stay (log, days) (r = 0.45).

CONCLUSIONS

S100B levels were independently correlated with intracranial pathology, but also with the extent of extracranial injury. Length of stay and ISS were both correlated with the admission levels of S100B in bicycle trauma, suggesting S100B to be a good marker of aggregated injury severity. Further studies are warranted to confirm our findings.

S100B and NSE serum concentrations after simulated diving in rats

The purpose of this study was to assess whether one could detect S100 calcium-binding protein B (S100B) and neuron-specific enolase (NSE) in serum of rats after a simulated dive breathing air, with the main hypothesis that the serum concentrations of S100B and NSE in rats will increase above pre-exposure levels following severe decompression stress measured as venous gas emboli (VGE). The dive group was exposed to a simulated air dive to 700 kPa for 45 min. Pulmonary artery was monitored for vascular gas bubbles by ultrasound. Pre- and postdive blood samples were analyzed for S100B and NSE using commercially available Elisa kits. There was no increase in serum S100B or NSE after simulated diving and few of the animals were showing high bubble grades after the dives. The present study examined whether the protein biomarkers S100B and NSE could be found in serum from rats after exposure to a simulated dive to 700 kPa for 45 min breathing air. There were no differences in serum concentrations before versus after the dive exposure. This may be explained by the lack of vascular gas bubbles after the dives.

Comparative Assessment of the Prognostic Value of Biomarkers in Traumatic Brain Injury Reveals an Independent Role for Serum Levels of Neurofilament Light

Traumatic brain injury (TBI) is a common cause of death and disability, worldwide. Early determination of injury severity is essential to improve care. Neurofilament light (NF-L) has been introduced as a marker of neuroaxonal injury in neuroinflammatory/-degenerative diseases. In this study we determined the predictive power of serum (s-) and cerebrospinal fluid (CSF-) NF-L levels towards outcome, and explored their potential correlation to diffuse axonal injury (DAI). A total of 182 patients suffering from TBI admitted to the neurointensive care unit at a level 1 trauma center were included. S-NF-L levels were acquired, together with S100B and neuron-specific enolase (NSE). CSF-NF-L was measured in a subcohort (n = 84) with ventriculostomies. Clinical and neuro-radiological parameters, including computerized tomography (CT) and magnetic resonance imaging, were included in the analyses. Outcome was assessed 6 to 12 months after injury using the Glasgow Outcome Score (1-5). In univariate proportional odds analyses mean s-NF-L, -S100B and -NSE levels presented a pseudo-R2 Nagelkerke of 0.062, 0.214 and 0.074 in correlation to outcome, respectively. In a multivariate analysis, in addition to a model including core parameters (pseudo-R2 0.33 towards outcome; Age, Glasgow Coma Scale, pupil response, Stockholm CT score, abbreviated injury severity score, S100B), S-NF-L yielded an extra 0.023 pseudo-R2 and a significantly better model (p = 0.006) No correlation between DAI or CT assessed-intracranial damage and NF-L was found. Our study thus demonstrates that S-NF-L correlates to TBI outcome, even if used in models with S100B, indicating an independent contribution to the prediction, perhaps by reflecting different pathophysiological processes, not possible to monitor using conventional neuroradiology. Although we did not find a predictive value of NF-L for DAI, this cannot be completely excluded. We suggest further studies, with volume quantification of axonal injury, and a prolonged sampling time, in order to better determine the connection between NF-L and DAI.

Circulating biomarkers in malignant melanoma

Melanoma is an aggressive tumor with increasing incidence worldwide. Biomarkers are valuable tools to minimize the cost and improve efficacy of treatment of this deadly disease. Serological markers have not widely been introduced in routine clinical practice due to their insufficient diagnostic sensitivity and specificity. It is likely that the lack of objective responses with traditional treatment hinder biomarker research and development in melanoma. Recently, new drugs and therapies have, however, emerged in advanced melanoma with noticeable objective response ratio and survival. In this new scenario, serological tumor markers should be revisited. In addition, other potential circulating biomarkers such as cell-free DNA, exosomes, microRNA, and circulating tumor cells have also been identified. In this review, we summarize classical and emerging tumor markers and discuss their possible roles in emerging therapeutics.

Secondary peaks of S100B in serum relate to subsequent radiological pathology in traumatic brain injury

INTRODUCTION

Patients suffering from severe traumatic brain injury (TBI) often develop secondary brain lesions that may worsen outcome. S100B, a biomarker of brain damage, has been shown to increase in response to secondary cerebral deterioration. The aim of this study was to analyze the occurrence of secondary increases in serum levels of S100B and their relation to potential subsequent radiological pathology present on CT/MRI-scans.

METHODS

Retrospective study from a trauma level 1 hospital, neuro-intensive care unit. 250 patients suffering from TBI were included. Inclusion required a minimum of two radiological examinations and at least three serum samples of S100B, with at least one >48 h after trauma.

RESULTS

Secondary pathological findings on CT/MRI, present in 39 % (n = 98) of the patients, were highly correlated to secondary increases of ≥0.05 μg/L S100B (P < 0.0001, pseudo-R (2) 0.532). Significance remained also after adjusting for known important TBI predictors. In addition, secondary radiological findings were significantly correlated to outcome (Glasgow Outcome Score, GOS) in uni-(P < 0.0001, pseudo-R (2) 0.111) and multivariate analysis. The sensitivity and specificity of detecting later secondary radiological findings was investigated at three S100B cut-off levels: 0.05, 0.1, and 0.5 μg/L. A secondary increase of ≥0.05 μg/L had higher sensitivity (80 %) but lower specificity (89 %), compared with a secondary increase of ≥0.5 μg/L (16 % sensitivity, 98 % specificity), to detect secondary radiological findings.

CONCLUSIONS

Secondary increases in serum levels of S100B, even as low as ≥0.05 μg/L, beyond 48 h after TBI are strongly correlated to the development of clinically significant secondary radiological findings.

S100B as a marker for brain damage and blood-brain barrier disruption following exercise

BACKGROUND

S100B level in the blood has been used as a marker for brain damage and blood-brain barrier (BBB) disruption. Elevations of S100B levels after exercise have been observed, suggesting that the BBB may be compromised during exercise. However, an increase in S100B levels may be confounded by other variables.

OBJECTIVES

The primary objective of this review was to compile findings on the relationship between S100B and exercise in order to determine if this protein is a valid marker for BBB disruptions during exercise. The secondary objective was to consolidate known factors causing S100B increases that may give rise to inaccurate interpretations of S100B levels.

DATA SOURCES AND STUDY SELECTION

PubMed, Web of Science and ScienceDirect were searched for relevant studies up to January 2013, in which S100B measurements were taken after a bout of exercise. Animal studies were excluded. Variables of interest such as the type of activity, exercise intensities, duration, detection methods, presence and extent of head trauma were examined and compiled.

RESULTS

This review included 23 studies; 15 (65 %) reported S100B increases after exercise, and among these, ten reported S100B increases regardless of intervention, while five reported increases in only some trials but not others. Eight (35 %) studies reported no increases in S100B levels across all trials. Most baseline S100B levels fall below 0.16 μg/L, with an increase in S100B levels of less than 0.07 μg/L following exercise. Factors that are likely to affect S100B levels include exercise intensity, and duration, presence and extent of head trauma. Several other probable factors influencing S100B elevations are muscle breakdown, level of training and oxidative stress, but current findings are still weak and inconclusive.

CONCLUSIONS

Elevated S100B levels have been recorded following exercise and are mostly attributed to either an increase in BBB permeability or trauma to the head. However, even in the absence of head trauma, it appears that the BBB may be compromised following exercise, with the severity dependent on exercise intensity.

Neuroantibody biomarkers: links and challenges in environmental neurodegeneration and autoimmunity

The majority of neurodegenerative (ND) and autoimmune diseases (AID) remain idiopathic. The contribution of environmental chemicals to the development of these disorders has become of great interest in recent years. A convergence of mechanism between of ND and AID development has also emerged. In the case of ND, including neurotoxicity, the focus of this review, work over the last two decade in the realm of biomarker development, indicates that the immune response provides a venue whereby humoral immunity, in the form of autoantibodies to nervous system specific proteins, or neuroantibodies (NAb), may provide, once validated, a sensitive high throughput surrogate biomarker of effect with the potential of predicting outcome in absence of overt neurotoxicity/neurodegeneration. In addition, NAb may prove to be a contributor to the progression of the nervous system pathology, as well as biomarker of stage and therapeutic efficacy. There is a compelling need for biomarkers of effect in light of the introduction of new chemicals, such as nanoengineered material, where potential neurotoxicity remains to be defined. Furthermore, the convergence of mechanisms associated with ND and AID draws attention to the neglected arena of angiogenesis in defining the link between environment, ND, and AID.

Protein S-100 and neuron-specific enolase serum levels remain unaffected by electroconvulsive therapy in patients with depression

The mechanism of the reversible cognitive deficits that might occur within an electroconvulsive therapy (ECT) treatment has not been clarified in a substantial way yet. Although the data available so far do not point towards a cause due to any structural or diffuse damage, further clarification, especially of the role of S-100 seems to be necessary before robust conclusions can be drawn. Serum levels of protein S-100 and neuron-specific enolase (NSE) were analysed in 19 patients with depression, who received ECT. The sampling was adjusted for the short half-life of protein S-100. Several outcome parameters such as Hamilton Depression Rating Scale and Mini-mental state examination before and after the ECT, response and remission to the treatment were recorded. S-100 and NSE levels at baseline, 30 and 60 min after the third session and after the end of the ECT remained stable. S-100 and NSE levels were neither associated with antidepressant response or remission nor with alterations in the cognitive performance. Although aiming for detecting potential rise in these established brain damage markers, an increase due to ECT was not observed, which is in line with the previous studies concerning the safety of ECT on a cellular basis.