CSF antithrombin III and disruption of the blood-brain barrier

The hemostatic system in chronic brain diseases: A new challenging frontier?

Neurological diseases (ND), including neurodegenerative diseases (NDD) and psychiatric disorders (PD), present a significant public health challenge, ranking third in Europe for disability and premature death, following cardiovascular diseases and cancers. In 2017, approximately 540 million cases of ND were reported among Europe's 925 million people, with strokes, dementia, and headaches being most prevalent. Nowadays, more and more evidence highlight the hemostasis critical role in cerebral homeostasis and vascular events. Indeed, hemostasis, thrombosis, and brain abnormalities contributing to ND form a complex and poorly understood equilibrium. Alterations in vascular biology, particularly involving the blood-brain barrier, are implicated in ND, especially dementia, and PD. While the roles of key coagulation players such as thrombin and fibrinogen are established, the roles of other hemostasis components are less clear. Moreover, the involvement of these elements in psychiatric disease pathogenesis is virtually unstudied, except in specific pathological models such as antiphospholipid syndrome. Advanced imaging techniques, primarily functional magnetic resonance imaging and its derivatives like diffusion tensor imaging, have been developed to study brain areas affected by ND and to improve our understanding of the pathophysiology of these diseases. This literature review aims to clarify the current understanding of the connections between hemostasis, thrombosis, and neurological diseases, as well as explore potential future diagnostic and therapeutic strategies.

Application of Proteomics in Cancer: Recent Trends and Approaches for Biomarkers Discovery

Proteomics has become an important field in molecular sciences, as it provides valuable information on the identity, expression levels, and modification of proteins. For example, cancer proteomics unraveled key information in mechanistic studies on tumor growth and metastasis, which has contributed to the identification of clinically applicable biomarkers as well as therapeutic targets. Several cancer proteome databases have been established and are being shared worldwide. Importantly, the integration of proteomics studies with other omics is providing extensive data related to molecular mechanisms and target modulators. These data may be analyzed and processed through bioinformatic pipelines to obtain useful information. The purpose of this review is to provide an overview of cancer proteomics and recent advances in proteomic techniques. In particular, we aim to offer insights into current proteomics studies of brain cancer, in which proteomic applications are in a relatively early stage. This review covers applications of proteomics from the discovery of biomarkers to the characterization of molecular mechanisms through advances in technology. Moreover, it addresses global trends in proteomics approaches for translational research. As a core method in translational research, the continued development of this field is expected to provide valuable information at a scale beyond that previously seen.

Liquid Biomarkers for Improved Diagnosis and Classification of CNS Tumors

Liquid biopsy, as a non-invasive technique for cancer diagnosis, has emerged as a major step forward in conquering tumors. Current practice in diagnosis of central nervous system (CNS) tumors involves invasive acquisition of tumor biopsy upon detection of tumor on neuroimaging. Liquid biopsy enables non-invasive, rapid, precise and, in particular, real-time cancer detection, prognosis and treatment monitoring, especially for CNS tumors. This approach can also uncover the heterogeneity of these tumors and will likely replace tissue biopsy in the future. Key components of liquid biopsy mainly include circulating tumor cells (CTC), circulating tumor nucleic acids (ctDNA, miRNA) and exosomes and samples can be obtained from the cerebrospinal fluid, plasma and serum of patients with CNS malignancies. This review covers current progress in application of liquid biopsies for diagnosis and monitoring of CNS malignancies.

High CSF thrombin concentration and activity is associated with an unfavorable outcome in patients with intracerebral hemorrhage

Background

The cerebral thrombin system is activated in the early stage after intracerebral hemorrhage (ICH). Expression of thrombin leads to concentration dependent secondary neuronal damage and detrimental neurological outcome. In this study we aimed to investigate the impact of thrombin concentration and activity in the cerebrospinal fluid (CSF) of patients with ICH on clinical outcome.

Methods

Patients presenting with space-occupying lobar supratentorial hemorrhage requiring extra-ventricular drainage (EVD) were included in our study. The CSF levels of thrombin, its precursor prothrombin and the Thrombin-Antithrombin complex (TAT) were measured using enzyme linked immune sorbent assays (ELISA). The oxidative stress marker Superoxide dismutase (SOD) was assessed in CSF. Initial clot size and intraventricular hemorrhage (IVH) volume was calculated based on by computerized tomography (CT) upon admission to our hospital. Demographic data, clinical status at admission and neurological outcome were assessed using the modified Rankin Scale (mRS) at 6-weeks and 6-month after ICH.

Results

Twenty-two consecutive patients (9 females, 11 males) with supratentorial hemorrhage were included in this study. CSF concentrations of prothrombin (p < 0.005), thrombin (p = 0.005) and TAT (p = 0.046) were statistical significantly different in patients with ICH compared to non-hemorrhagic CSF samples. CSF concentrations of thrombin 24h after ICH correlated with the mRS index after 6 weeks (r² = 0.73; < 0.005) and 6 months (r² = 0.63; < 0.005) after discharge from hospital. Thrombin activity, measured via TAT as surrogate parameter of coagulation, likewise correlated with the mRS at 6 weeks (r² = 0.54; < 0.01) and 6 months (r² = 0.66; < 0.04). High thrombin concentrations coincide with higher SOD levels 24h after ICH (p = 0.01).

Conclusion

In this study we found that initial thrombin concentration and activity in CSF of ICH patients did not correlate with ICH and IVH volume but are associated with a poorer functional neurological outcome. These findings support mounting evidence of the role of thrombin as a contributor to secondary injury formation after ICH.

A Multiplex Assay for the Stratification of Patients with Primary Central Nervous System Lymphoma Using Targeted Mass Spectrometry

Primary central nervous system lymphomas (PCNSL) account for approximately 2% to 3% of all primary brain tumors. Until now, neuropathological tumor tissue analysis, most frequently gained by stereotactic biopsy, is still the diagnostic gold standard. Here, we rigorously analyzed two independent patient cohorts comprising the clinical entities PCNSL (n = 47), secondary central nervous system lymphomas (SCNSL; n = 13), multiple sclerosis (MS, n = 23), glioma (n = 10), other tumors (n = 17) and tumor-free controls (n = 21) by proteomic approaches. In total, we identified more than 1220 proteins in the cerebrospinal fluid (CSF) and validated eight candidate biomarkers by a peptide-centric approach in an independent patient cohort (n = 63). Thus, we obtained excellent diagnostic accuracy for the stratification between PCNSL, MS and glioma patients as well as tumor-free controls for three peptides originating from the three proteins VSIG4, GPNMB4 and APOC2. The combination of all three biomarker candidates resulted in diagnostic accuracy with an area under the curve (AUC) of 0.901 (PCNSL vs. MS), AUC of 0.953 (PCNSL vs. glioma) and AUC 0.850 (PCNSL vs. tumor-free control). In summary, the determination of VSIG4, GPNMB4 and APOC2 in CSF as novel biomarkers for supporting the diagnosis of PCNSL is suggested.

Diagnostic markers for CNS lymphoma in blood and cerebrospinal fluid: a systematic review

Diagnosing central nervous system (CNS) lymphoma remains a challenge. Most patients have to undergo brain biopsy to obtain tissue for diagnosis, with associated risks of serious complications. Diagnostic markers in blood or cerebrospinal fluid (CSF) could facilitate early diagnosis with low complication rates. We performed a systematic literature search for studies on markers in blood or cerebrospinal fluid for the diagnosis CNS lymphoma and assessed the methodological quality of studies with the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS‐2). We evaluated diagnostic value of the markers at a given threshold, as well as differences between mean or median levels in patients versus control groups. Twenty‐five studies were included, reporting diagnostic value for 18 markers in CSF (microRNAs ‐21, ‐19b, and ‐92a, RNU2‐1f, CXCL13, interleukins ‐6, ‐8, and ‐10, soluble interleukin‐2‐receptor, soluble CD19, soluble CD27, tumour necrosis factor‐alfa, beta‐2‐microglobulin, antithrombin III, soluble transmembrane activator and calcium modulator and cyclophilin ligand interactor, soluble B cell maturation antigen, neopterin and osteopontin) and three markers in blood (microRNA‐21 soluble CD27, and beta‐2‐microglobulin). All studies were at considerable risk of bias and there were concerns regarding the applicability of 15 studies. CXCL‐13, beta‐2‐microglobulin and neopterin have the highest potential in diagnosing CNS lymphoma, but further study is still needed before they can be used in clinical practice.

Proteomic changes in cerebrospinal fluid from primary central nervous system lymphoma patients are associated with protein ectodomain shedding

Primary central nervous system lymphomas (PCNSLs) are mature B-cell lymphomas confined to the central nervous system (CNS). Blood-brain barrier (BBB) dysfunction drastically alters the cerebrospinal fluid (CSF) proteome in PCNSL patients. To reveal the interaction of PCNSL tumors with CNS structures and the vasculature, we conducted a whole-proteome analysis of CSF from PCNSL patients (n = 17 at initial diagnosis) and tumor-free controls (n = 10) using label-free quantitative mass spectrometry. We identified 601 proteins in the CSF proteome using a one-step approach without further prefractionation, and quantified 438 proteins in detail using the Hi-N method. An immunoassay revealed that 70% of the patients in our unselected PCNSL patient cohort had BBB dysfunction. Correlation analysis indicated that 127 (30%) of the quantified proteins were likely increased in PCSNL patients due to BBB dysfunction. After the exclusion of these proteins, 66 were found to differ in abundance (fold-change > 2.0, p < 0.05) between PCNSL and control CSF proteomes, and most of those were associated with the CNS. These data also provide the first evidence that proteomic changes in CSF from PCNSL patients are mainly associated with protein ectodomain shedding, and that shedding of human leukocyte antigen class 2 proteins is a mechanism of tumor-cell immune evasion.

Tumor-Associated CSF MicroRNAs for the Prediction and Evaluation of CNS Malignancies

Cerebrospinal fluid (CSF) is a readily reachable body fluid that is reflective of the underlying pathological state of the central nervous system (CNS). Hence it has been targeted for biomarker discovery for a variety of neurological disorders. CSF is also the major route for seeding metastases of CNS malignancies and its analysis could be informative for diagnosis and risk stratification of brain cancers. Recently, modern high-throughput, microRNAs (miRNAs) measuring technology has enabled sensitive detection of distinct miRNAs that are bio-chemicallystable in the CSF and can distinguish between different types of CNS cancers. Owing to the fact that a CSF specimen can be obtained with relative ease, analysis of CSF miRNAs could be a promising contribution to clinical practice. In this review, we examine the current scientific knowledge on tumor associated CSF miRNAs that could guide diagnosis of different brain cancer types, or could be helpful in predicting disease progression and therapy response. Finally, we highlight their potential applications clinically as biomarkers and discuss limitations.

Antithrombin III is probably not a suitable biomarker for diagnosis of primary central nervous system lymphoma

Antithrombin III (AT III) in cerebrospinal fluid (CSF) has been suggested to have high specificity and sensitivity in separating primary central nervous system (CNS) lymphoma from other neurological conditions. We measured with ELISA CSF and serum AT III and albumin levels in 12 lymphoma patients with CNS involvement, 30 lymphoma patients without CNS involvement, and 41 patients with non-neoplastic neurological diseases. AT III immunostaining was also carried out, in lymphoma patients. Both CSF AT III and albumin levels were higher in lymphoma patients with CNS involvement. AT III/albumin ratio in CSF was the most sensitive and specific measure for diagnosis. Lowest it was in patients with known CNS lymphoma. Serum AT III levels were lower both in CNS lymphoma and systemic lymphoma. CSF AT III levels were shown to be higher in lymphoma patients with CNS involvement, when AT III/albumin ratios were lower. This was probably a result of lowered serum AT III levels, indicating that high levels of AT III in CSF might reflect only leakage of the blood-brain barrier. Thus, AT III fails to be a specific marker for diagnosis of lymphoma CNS involvement.

CSF in Alzheimer's disease

Alzheimer's disease (AD) is a progressive brain amyloidosis that injures brain regions involved in memory consolidation and other cognitive functions. Neuropathologically, the disease is characterized by accumulation of a 42-amino acid protein called amyloid beta, and N-terminally truncated fragments thereof, in extracellular senile plaques together with intraneuronal inclusions of hyperphosphorylated tau protein in neurofibrillary tangles, and neuronal and axonal degeneration and loss. Clinical chemistry tests for these pathologies have been developed for use on cerebrospinal fluid samples. Here, we review what these markers have taught us on the disease process in AD and how they can be implemented in routine clinical chemistry. We also provide an update on new marker development and ongoing analytical standardization effort.

Known and emerging biomarkers of leptomeningeal metastasis and its response to treatment

Leptomeningeal metastasis (LM) is the metastatic dissemination of malignant cells to the leptomeninges and the subarachnoid space of the CNS, affecting approximately 8% of all cancer patients. Cerebrospinal fluid cytology is currently the gold standard for diagnosis of LM and assessment of treatment response, but it has relatively low sensitivity. Thus, specific biomarkers of LM may allow for earlier diagnosis and treatment. This article reviews known tumor markers for LM and describes recent work to find LM-specific markers, such as angiogenesis-related proteins. Novel methods of protein profiling that may aid this search are also described; these methods still need to be standardized and validated to gain widespread acceptance. Nevertheless, we anticipate that future biomarkers will have not only the potential to detect LM, but to predict its progression and response to treatment.