Repopulated microglia after pharmacological depletion decrease dendritic spine density in adult mouse brain.

Microglia are innate immune cells in the brain and show exceptional heterogeneity. They are key players in brain physiological development regulating synaptic plasticity and shaping neuronal networks. In pathological disease states, microglia-induced synaptic pruning mediates synaptic loss and targeting microglia was proposed as a promising therapeutic strategy. However, the effect of microglia depletion and subsequent repopulation on dendritic spine density and neuronal function in the adult brain is largely unknown. In this study, we investigated whether pharmacological microglia depletion affects dendritic spine density after long-term permanent microglia depletion and after short-term microglia depletion with subsequent repopulation. Long-term microglia depletion using colony-stimulating-factor-1 receptor (CSF1-R) inhibitor PLX5622 resulted in increased overall spine density, especially of mushroom spines, and increased excitatory postsynaptic current amplitudes. Short-term PLX5622 treatment with subsequent repopulation of microglia had an opposite effect resulting in activated microglia with increased synaptic phagocytosis and consequently decreased spine density and reduced excitatory neurotransmission, while Barnes maze and elevated plus maze testing was unaffected. Moreover, RNA sequencing data of isolated repopulated microglia showed an activated and proinflammatory phenotype. Long-term microglia depletion might be a promising therapeutic strategy in neurological diseases with pathological microglial activation, synaptic pruning, and synapse loss. However, repopulation after depletion induces activated microglia and results in a decrease of dendritic spines possibly limiting the therapeutic application of microglia depletion. Instead, persistent modulation of pathological microglia activity might be beneficial in controlling synaptic damage.

Leveraging artificial intelligence in neurosurgery-unveiling ChatGPT for neurosurgical discharge summaries and operative reports.

PURPOSE: Chat generative pre-trained transformer (GPT) is a novel large pre-trained natural language processing software that can enable scientific writing amongst a litany of other features. Given this, there is a growing interest in exploring the use of ChatGPT models as a modality to facilitate/assist in the provision of clinical care. METHODS: We investigated the time taken for the composition of neurosurgical discharge summaries and operative reports at a major University hospital. In so doing, we compared currently employed speech recognition software (i.e., SpeaKING) vs novel ChatGPT for three distinct neurosurgical diseases: chronic subdural hematoma, spinal decompression, and craniotomy. Furthermore, factual correctness was analyzed for the abovementioned diseases. RESULTS: The composition of neurosurgical discharge summaries and operative reports with the assistance of ChatGPT leads to a statistically significant time reduction across all three diseases/report types: p < 0.001 for chronic subdural hematoma, p < 0.001 for decompression of spinal stenosis, and p < 0.001 for craniotomy and tumor resection. However, despite a high degree of factual correctness, the preparation of a surgical report for craniotomy proved to be significantly lower (p = 0.002). CONCLUSION: ChatGPT assisted in the writing of discharge summaries and operative reports as evidenced by an impressive reduction in time spent as compared to standard speech recognition software. While promising, the optimal use cases and ethics of AI-generated medical writing remain to be fully elucidated and must be further explored in future studies.

Discrepancies Between Objective and Subjective Outcomes of and Quality of Life During Molding Helmet Therapy for Cranial Deformities.

Positional skull deformities have been on the rise for decades and can be treated with molding helmets in early childhood. Parents often fear later cosmetic stigmatization, but also a reduced quality of life (QoL) during treatment. The aim of this study was to examine therapy results in our patient collection from a new perspective. Cranial vault asymmetry (CVA), cranial vault asymmetry index (CVAI), and cranial index (CI) were compared before and after molding helmet therapy. Correction was defined by a decrease in CVA <3.5 mm and CI <90%. Subjective therapy outcome, side effects and QoL from the parents' perspective were determined using a questionnaire. There were 25 patients included. Differences between pretherapeutic and posttherapeutic CVA, CVAI, and CI were significant (P<0.01). An objective correction according to the defined values was observed in only 12% of cases. However, 76% of parents stated that their child's skull shape was normal after therapy. There were 60 side effects reported in 23 cases. The QoL of 21 children was assessed as unimpaired during helmet therapy. Even though complete normalization was rarely observed, the parameters were significantly different after therapy, and subjective reduction in skull deformity was common.

Treatment of very elderly glioblastoma patients ≥ 75 years of age: whom to treat.

PURPOSE: The prognosis of patients ≥ 75 years suffering from glioblastoma is poor. Novel therapies are usually reserved for patients ≤ 70 years. In an aging population, treatment of very elderly patients remains a challenge. METHODS: Between 2010 and 2018, a total of 977 glioblastoma patients were treated at our institution. Of these, 143 patients were ≥ 75 years at diagnosis. Primary procedure was surgical resection or biopsy followed by adjuvant treatment, whenever possible. We retrospectively investigated overall survival (OS) and potential prognostic factors influencing survival, including Karnofsky Performance Status (KPS), surgical therapy, adjuvant therapy as well as MGMT promotor status. RESULTS: In very elderly patients, median age was 79 years (range: 75-110). Biopsy only was performed in 104 patients; resection was performed in 39 patients. Median OS for the entire cohort was 5.9 months. Univariate analysis showed that KPS at presentation (≥ 70 vs. ≤60), surgery vs. biopsy, adjuvant chemotherapy and adjuvant radiotherapy were significantly associated with OS (6 vs. 3, p < 0.0111; 12 vs. 4, p = 0.0011; 11 vs. 4, p = 0.0003 and 10 vs. 1.5 months, p < 0.0001, respectively). Multivariate analysis confirmed adjuvant radiotherapy (p < 0.0001) and chemotherapy (p = 0.0002) as independent factors influencing OS. CONCLUSION: For very elderly patients, the natural course of disease without treatment is devastating. These patients benefit from multimodal treatment including adjuvant radiotherapy and chemotherapy. A beneficial effect of resection has not been demonstrated. Treatment options and outcomes should be thoughtfully discussed before treatment decisions are made.

Retrospective comparison of long-term functionality and revision rate of two different shunt valves in pediatric and adult patients.

PURPOSE: The most frequent therapy of hydrocephalus is implantation of ventriculoperitoneal shunts for diverting cerebrospinal into the peritoneal cavity. We compared two adjustable valves, proGAV and proGAV 2.0, for complications resulting in revision surgery. METHODS: Four hundred patients undergoing primary shunt implantation between 2014 and 2020 were analyzed for overall revision rate, 1-year revision rate, and revision-free survival observing patient age, sex, etiology of hydrocephalus, implantation site, prior diversion of cerebrospinal fluid, and cause of revision. RESULTS: All data were available of all 400 patients (female/male 208/192). Overall, 99 patients underwent revision surgery after primary implantation. proGAV valve was implanted in 283 patients, and proGAV 2.0 valves were implanted in 117 patients. There was no significant difference between the two shunt valves concerning revision rate (p = 0.8069), 1-year revision rate (p = 0.9077), revision-free survival (p = 0.6921), and overall survival (p = 0.3232). Regarding 1-year revision rate, we observed no significant difference between the two shunt valves in pediatric patients (40.7% vs 27.6%; p = 0.2247). Revision operation had to be performed more frequently in pediatric patients (46.6% vs 24.8%; p = 0.0093) with a significant higher number of total revisions with proGAV than proGAV 2.0 (33 of 59 implanted shunts [55.9%] vs. 8 of 29 implanted shunts [27.6%]; p = 0.0110) most likely due to longer follow-up in the proGAV-group. For this reason, we clearly put emphasis on analyzing results regarding 1-year revision rate. CONCLUSION: According to the target variables we analyzed, aside from lifetime revision rate in pediatric patients, there is no significant difference between the two shunt valves.

Direct oral anticoagulants vs. low-molecular-weight heparin for pulmonary embolism in patients with glioblastoma.

Glioblastoma (GBM) is a cancer type with high thrombogenic potential and GBM patients are therefore at a particularly high risk for thrombotic events. To date, only limited data on anticoagulation management after pulmonary embolism (PE) in GBM is available and the sporadic use of DOACs remains off-label. A retrospective cohort analysis of patients with GBM and postoperative, thoracic CT scan confirmed PE was performed. Clinical course, follow-up at 6 and 12 months and the overall survival (OS) were evaluated using medical charts and neuroradiological data. Out of 584 GBM patients, 8% suffered from postoperative PE. Out of these, 30% received direct oral anticoagulants (DOACs) and 70% low-molecular-weight heparin (LMWH) for therapeutic anticoagulation. There was no significant difference in major intracranial hemorrhage (ICH), re-thrombosis, or re-embolism between the two cohorts. Although statistically non-significant, a tendency to reduced mRS at 6 and 12 months was observed in the LMWH cohort. Furthermore, patients receiving DOACs had a statistical benefit in OS. In our analysis, DOACs showed a satisfactory safety profile in terms of major ICH, re-thrombosis, and re-embolism compared to LMWH in GBM patients with postoperative PE. Prospective, randomized trials are urgent to evaluate DOACs for therapeutic anticoagulation in GBM patients with PE.

Preoperative anaemia and red blood cell transfusion in patients with aneurysmal subarachnoid and intracerebral haemorrhage - a multicentre subanalysis of the German PBM Network Registry.

PURPOSE: Anaemia is common in patients presenting with aneurysmal subarachnoid (aSAH) and intracerebral haemorrhage (ICH). In surgical patients, anaemia was identified as an idenpendent risk factor for postoperative mortality, prolonged hospital length of stay (LOS) and increased risk of red blood cell (RBC) transfusion. This multicentre cohort observation study describes the incidence and effects of preoperative anaemia in this critical patient collective for a 10-year period. METHODS: This multicentre observational study included adult in-hospital surgical patients diagnosed with aSAH or ICH of 21 German hospitals (discharged from 1 January 2010 to 30 September 2020). Descriptive, univariate and multivariate analyses were performed to investigate the incidence and association of preoperative anaemia with RBC transfusion, in-hospital mortality and postoperative complications in patients with aSAH and ICH. RESULTS: A total of n = 9081 patients were analysed (aSAH n = 5008; ICH n = 4073). Preoperative anaemia was present at 28.3% in aSAH and 40.9% in ICH. RBC transfusion rates were 29.9% in aSAH and 29.3% in ICH. Multivariate analysis revealed that preoperative anaemia is associated with a higher risk for RBC transfusion (OR = 3.25 in aSAH, OR = 4.16 in ICH, p < 0.001), for in-hospital mortality (OR = 1.48 in aSAH, OR = 1.53 in ICH, p < 0.001) and for several postoperative complications. CONCLUSIONS: Preoperative anaemia is associated with increased RBC transfusion rates, in-hospital mortality and postoperative complications in patients with aSAH and ICH. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02147795, https://clinicaltrials.gov/ct2/show/NCT02147795.

TGF-ß activates pericytes via induction of the epithelial-to-mesenchymal transition protein SLUG in glioblastoma.

AIMS: In primary central nervous system tumours, epithelial-to-mesenchymal transition (EMT) gene expression is associated with increased malignancy. However, it has also been shown that EMT factors in gliomas are almost exclusively expressed by glioma vessel-associated pericytes (GA-Peris). In this study, we aimed to identify the mechanism of EMT in GA-Peris and its impact on angiogenic processes. METHODS: In glioma patients, vascular density and the expression of the pericytic markers platelet derived growth factor receptor (PDGFR)-ß and smooth muscle actin (αSMA) were examined in relation to the expression of the EMT transcription factor SLUG and were correlated with survival of patients with glioblastoma (GBM). Functional mechanisms of SLUG regulation and the effects on primary human brain vascular pericytes (HBVP) were studied in vitro by measuring proliferation, cell motility and growth characteristics. RESULTS: The number of PDGFR-ß- and αSMA-positive pericytes did not change with increased malignancy nor showed an association with the survival of GBM patients. However, SLUG-expressing pericytes displayed considerable morphological changes in GBM-associated vessels, and TGF-ß induced SLUG upregulation led to enhanced proliferation, motility and altered growth patterns in HBVP. Downregulation of SLUG or addition of a TGF-ß antagonising antibody abolished these effects. CONCLUSIONS: We provide evidence that in GA-Peris, elevated SLUG expression is mediated by TGF-ß, a cytokine secreted by most glioma cells, indicating that the latter actively modulate neovascularisation not only by modulating endothelial cells, but also by influencing pericytes. This process might be responsible for the formation of an unstructured tumour vasculature as well as for the breakdown of the blood-brain barrier in GBM.

Linking epigenetic signature and metabolic phenotype in IDH mutant and IDH wildtype diffuse glioma.

AIMS: Changes in metabolism are known to contribute to tumour phenotypes. If and how metabolic alterations in brain tumours contribute to patient outcome is still poorly understood. Epigenetics impact metabolism and mitochondrial function. The aim of this study is a characterisation of metabolic features in molecular subgroups of isocitrate dehydrogenase mutant (IDHmut) and isocitrate dehydrogenase wildtype (IDHwt) gliomas. METHODS: We employed DNA methylation pattern analyses with a special focus on metabolic genes, large-scale metabolism panel immunohistochemistry (IHC), qPCR-based determination of mitochondrial DNA copy number and immune cell content using IHC and deconvolution of DNA methylation data. We analysed molecularly characterised gliomas (n = 57) for in depth DNA methylation, a cohort of primary and recurrent gliomas (n = 22) for mitochondrial copy number and validated these results in a large glioma cohort (n = 293). Finally, we investigated the potential of metabolic markers in Bevacizumab (Bev)-treated gliomas (n = 29). RESULTS: DNA methylation patterns of metabolic genes successfully distinguished the molecular subtypes of IDHmut and IDHwt gliomas. Promoter methylation of lactate dehydrogenase A negatively correlated with protein expression and was associated with IDHmut gliomas. Mitochondrial DNA copy number was increased in IDHmut tumours and did not change in recurrent tumours. Hierarchical clustering based on metabolism panel IHC revealed distinct subclasses of IDHmut and IDHwt gliomas with an impact on patient outcome. Further quantification of these markers allowed for the prediction of survival under anti-angiogenic therapy. CONCLUSION: A mitochondrial signature was associated with increased survival in all analyses, which could indicate tumour subgroups with specific metabolic vulnerabilities.

Proposed definition of competencies for surgical neuro-oncology training.

OBJECTIVE: The aim of this work is to define competencies and entrustable professional activities (EPAs) to be imparted within the framework of surgical neuro-oncological residency and fellowship training as well as the education of medical students. Improved and specific training in surgical neuro-oncology promotes neuro-oncological expertise, quality of surgical neuro-oncological treatment and may also contribute to further development of neuro-oncological techniques and treatment protocols. Specific curricula for a surgical neuro-oncologic education have not yet been established. METHODS: We used a consensus-building approach to propose skills, competencies and EPAs to be imparted within the framework of surgical neuro-oncological training. We developed competencies and EPAs suitable for training in surgical neuro-oncology. RESULT: In total, 70 competencies and 8 EPAs for training in surgical neuro-oncology were proposed. EPAs were defined for the management of the deteriorating patient, the management of patients with the diagnosis of a brain tumour, tumour-based resections, function-based surgical resections of brain tumours, the postoperative management of patients, the collaboration as a member of an interdisciplinary and/or -professional team and finally for the care of palliative and dying patients and their families. CONCLUSIONS AND RELEVANCE: The present work should subsequently initiate a discussion about the proposed competencies and EPAs and, together with the following discussion, contribute to the creation of new training concepts in surgical neuro-oncology.

Two-step staged resection of giant olfactory groove meningiomas.

BACKGROUND: The surgical treatment of giant olfactory groove meningiomas (OGMs) with marked perilesional brain oedema is still a surgical challenge. After tumour resection, increase of brain oedema may occur causing dramatic neurological deterioration and even death of the patient. The objective of this paper is to describe surgical features of a two-step staged resection of these tumours performed to counter increase of postoperative brain oedema. METHODS: This two-step staged resection procedure was carried out in a consecutive series of 19 patients harbouring giant OGMs. As first step, a bifrontal craniectomy was performed followed by a right-sided interhemispherical approach. About 80% of the tumour mass was resected leaving behind a shell-shaped tumour remnant. In the second step, carried out after the patients' recovery from the first surgery and decline of oedema, the remaining part of the tumour was removed completely followed by duro- and cranioplasty. RESULTS: Ten patients recovered quickly from first surgery and the second operation was performed after a mean of 12.4 days. In eight patients, the second operation was carried out later between day 25 and 68 due to surgery-related complications, development of a trigeminal zoster, or to a persisting frontal brain oedema. Mean follow-up was 49.3 months and all but one patient had a good outcome regardless of surgery-related complications. CONCLUSIONS: Our results suggest that a two-step staged resection of giant OGMs minimizes the increase of postoperative brain oedema as far as possible and translates into lower morbidity and mortality.

Cholinergic innervation and ganglion cell distribution in Hirschsprung's disease.

BACKGROUND: The diagnostic gold standard of Hirschsprung's disease (HD) is based on the histopathological assessment of colorectal biopsies. Although data on cholinergic innervation and ganglion cell (GC) distribution exist, only few studies have examined these two key features together. We assessed the pattern of cholinergic innervation and the amount of GCs in colorectal specimens of 14 HD patients. METHODS: We established a semi-quantitative score for cholinergic innervation using acetylcholinesterase (AChE) enzyme histochemistry and quantitatively analyzed the number of GCs via NADH tetrazolium reductase (NADH) enzyme histochemistry. We examined both the entire length of the resected specimens as well as defined areas of the transition zone of both pathological and healthy appearing segment. RESULTS: High AChE score values were associated with absence of GCs, and AChE scores were inversely correlated with the number of GCs. Nevertheless, we observed several cases in which one of the two features revealed a normal distribution pattern, whereas the other still displayed pathological features. CONCLUSIONS: Our data support the need for transmural colon biopsies, to enable the best evaluation of both cholinergic innervation and GCs for a reliable assessment of HD.

Influence of pregnancy on glioma patients.

BACKGROUND: Data about the influence of pregnancy on progression-free survival and overall survival of glioma patients are sparse and controversial. We aimed at providing further evidence on this relation. METHODS: The course of 18 glioma patients giving birth to 23 children after tumor surgery was reviewed and compared to the course of 18 nulliparous female patients matched for tumor diagnosis including molecular markers, extent of resection, and tumor location. RESULTS: Tumor pathology was astrocytoma, oligodendroglioma, and ependymoma in 9, 6, and 3 patients, respectively. Time interval between tumor resection and delivery was 5.3 ± 4.4 years. All newborns were healthy after uneventful deliveries. Tumor progression was diagnosed before pregnancy in 4 patients and during pregnancy in 1 patient, and 4 patients displayed progressive disease 31.0 ± 11 months after delivery. Three of these latter patients underwent second surgery, whereas resection of recurrent tumor had been performed in 2 women before pregnancy. Among nulliparous patients, 9 women suffered from tumor progression, resulting in re-operation in 7 patients and/or further adjuvant treatment in 6 cases. Progression-free survival did not differ between patients with and patients without children (p = 0.4). Moreover, in both groups, median overall survival was not reached after a mean follow-up period of 9.7 ± 5.7 years in glioma patients who gave birth to a child and 8.9 ± 4.2 years in nulliparous glioma patients. CONCLUSION: Pregnancy does not seem to influence the clinical course of glioma patients. Likewise, glioma seems not to have an impact on delivered children's health.

Loss of histone H3K27me3 identifies a subset of meningiomas with increased risk of recurrence.

Epigenetic patterns on the level of DNA methylation have already been shown to separate clinically relevant subgroups of meningiomas. We here set out to identify potential prognostic implications of epigenetic modification on the level of histones with focus on H3K27 trimethylation (H3K27me3). H3K27me3 was assessed by immunohistochemistry on 232 meningiomas from 232 patients. In 194 cases, trimethylation was detected in tumor cells. In 25 cases, staining was limited to vessels while all tumor cells were negative. Finally, 13 cases yielded equivocal staining patterns. Reduced abundance of H3K27me3 in cases with staining limited to vessels was confirmed by mass spectrometry on a subset of cases. Lack of staining for H3K27me3 in all tumor cells was significantly associated with more rapid progression (p = 0.009). In line, H3K27me3-negative cases were associated with a DNA methylation pattern of the more aggressive types among the recently introduced DNA methylation groups. Also, NF2 and SUFU mutations were enriched among cases with complete lack of H3K27me3 staining in tumor cells (p < 0.0001 and p = 0.029, respectively). H3K27me3 staining pattern added significant prognostic insight into WHO grade II cases and in the compound subset of WHO grade I and II cases (p = 0.04 and p = 0.007, respectively). However, it did not further stratify within WHO grade III cases. Collectively, these data indicate that epigenetic modifications beyond DNA methylation are involved in the aggressiveness of meningioma. It also suggests that H3K27me3 immunohistochemistry might be a useful adjunct in meningioma diagnostics, particularly for cases with WHO grade II histology or at the borderline between WHO grade I and II.

Pre- and early postoperative GFAP serum levels in glioma and brain metastases.

SUBJECT: To date there is no established tumor marker for the clinical follow-up of glioblastoma, WHO grade IV, (GBM) which constitutes the most frequent and malignant primary brain tumor. However, since there is promising data that the serum glial fibrillary acidic protein (sGFAP) may serve as a biomarker for glial brain tumors, this prospective study aimed at evaluating the diagnostic relevance of perioperative changes in sGFAP levels for the assessment of residual glial tumor tissue in patients undergoing surgery of intracerebral tumors. METHODS: Serum GFAP was measured using an electrochemiluminometric immunoassay (ElecsysR GFAP prototype test, Roche Diagnostics, Penzberg/Germany) in 32 prospectively recruited patients between September 2009 and August 2010. Twenty-five were diagnosed with glioma and seven with brain metastases (BM). We assessed sGFAP levels prior to and at different time points during the early postoperative phase until patient discharge. RESULTS: There were only significant differences in the pre-operative sGFAP levels of patients with gliomas compared to BM (0.18 vs. 0.08 µg/l; p = 0.0198, Welch's t-Test). Even though there was an increase of sGFAP after surgery, there were no significant differences between glioma and BM patients at any other time point. Peak sGFAP levels where reached on postoperative day 1 followed by a slight decrease, but not reaching pre-operative levels until postop day 7. There was no significant correlation between postoperative glioma tumor volume and sGFAP levels in univariate analyses. CONCLUSION: According to our data sGFAP does not appear to be suitable to detect residual glioma tissue in the acute postoperative phase.

Focused review on seizures caused by meningiomas.

BACKGROUND: Meningiomas belong to the most common intracranial neoplasms in adults. One of the most common symptoms patients with meningioma experience is seizures. However, it remains unclear whether prophylactic preoperative anticonvulsant treatment is worthwhile. Furthermore, it is not clear which patients are likely to experience seizures in the course of the disease. In recent years, many studies and meta-analyses addressed this question with particular contradictory results. Therefore, we aimed to identify the most important risk factors for seizures in patients with meningiomas. METHODS: For the search terms "meningioma and seizure", "meningioma and epilepsy", and "Simpson and seizure" Medline query identified 865 articles. After applying inclusion and exclusion criteria, 20 papers were chosen for further study. The papers were analyzed for all risk factors for pre- and postoperative risk factors for seizures. RESULTS: Preoperative seizures were mostly associated with extensive brain edema, localization, and bigger tumor size. Even though data were sometimes very contradictory, higher postoperative seizure rate in patients with meningioma was associated with distinct localizations, preoperative seizures, tumor size, brain edema, extent of resection, tumor recurrence, and new neurological deficits. There were no randomized trials showing a prophylactic effect of anticonvulsant drugs. CONCLUSIONS: There are relevant risk factors for seizures in patients with meningioma. There is the need for a double blind randomized trial for the prophylactic use of antiepileptic drugs (AEDs).

DNA methylation-based classification and grading system for meningioma: a multicentre, retrospective analysis.

BACKGROUND: The WHO classification of brain tumours describes 15 subtypes of meningioma. Nine of these subtypes are allotted to WHO grade I, and three each to grade II and grade III. Grading is based solely on histology, with an absence of molecular markers. Although the existing classification and grading approach is of prognostic value, it harbours shortcomings such as ill-defined parameters for subtypes and grading criteria prone to arbitrary judgment. In this study, we aimed for a comprehensive characterisation of the entire molecular genetic landscape of meningioma to identify biologically and clinically relevant subgroups. METHODS: In this multicentre, retrospective analysis, we investigated genome-wide DNA methylation patterns of meningiomas from ten European academic neuro-oncology centres to identify distinct methylation classes of meningiomas. The methylation classes were further characterised by DNA copy number analysis, mutational profiling, and RNA sequencing. Methylation classes were analysed for progression-free survival outcomes by the Kaplan-Meier method. The DNA methylation-based and WHO classification schema were compared using the Brier prediction score, analysed in an independent cohort with WHO grading, progression-free survival, and disease-specific survival data available, collected at the Medical University Vienna (Vienna, Austria), assessing methylation patterns with an alternative methylation chip. FINDINGS: We retrospectively collected 497 meningiomas along with 309 samples of other extra-axial skull tumours that might histologically mimic meningioma variants. Unsupervised clustering of DNA methylation data clearly segregated all meningiomas from other skull tumours. We generated genome-wide DNA methylation profiles from all 497 meningioma samples. DNA methylation profiling distinguished six distinct clinically relevant methylation classes associated with typical mutational, cytogenetic, and gene expression patterns. Compared with WHO grading, classification by individual and combined methylation classes more accurately identifies patients at high risk of disease progression in tumours with WHO grade I histology, and patients at lower risk of recurrence among WHO grade II tumours (p=0·0096) from the Brier prediction test). We validated this finding in our independent cohort of 140 patients with meningioma. INTERPRETATION: DNA methylation-based meningioma classification captures clinically more homogenous groups and has a higher power for predicting tumour recurrence and prognosis than the WHO classification. The approach presented here is potentially very useful for stratifying meningioma patients to observation-only or adjuvant treatment groups. We consider methylation-based tumour classification highly relevant for the future diagnosis and treatment of meningioma. FUNDING: German Cancer Aid, Else Kröner-Fresenius Foundation, and DKFZ/Heidelberg Institute of Personalized Oncology/Precision Oncology Program.

Assessment of molecular markers demonstrates concordance between samples acquired via stereotactic biopsy and open craniotomy in both anaplastic astrocytomas and glioblastomas.

The classification, treatment and prognosis of high-grade gliomas has been shown to correlate with the expression of molecular markers (e.g. MGMT promotor methylation and IDH1 mutations). Acquisition of tumor samples may be obtained via stereotactic biopsy or open craniotomy. Between the years 2009 and 2013, 22 patients initially diagnosed with HGGs via stereotactic biopsy, that ultimately underwent open craniotomy for resection of their tumor were prospectively included in an institutional glioma database. MGMT promotor analysis was performed using methylation-specific (MS)-PCR and IDH1R132H mutation analysis was performed using immunohistochemistry. Three patients (13.7%) exhibited IDH1R132H mutations in samples obtained via stereotactic biopsy. Tissue derived from stereotaxic biopsy was demonstrated to have MGMT promotor methylation in ten patients (45.5%), while a non-methylated MGMT promotor was demonstrated in ten patients (45.5%); inconclusive results were obtained for the remaining two patients (9%) within our cohort. The initial histologic grading, IDH1R132H mutation and MGMT promotor methylation results were confirmed using samples obtained during open craniotomy in all but one patient; here inconclusive MGMT promotor analysis was obtained in contrast to that which was obtained via stereotactic biopsy. Tumor samples acquired via stereotactic biopsy provide accurate information with regard to clinically relevant molecular markers that have been shown to impact patient care decisions. The profile of markers analyzed in our cohort was nearly concordant between those samples obtained via stereotactic biopsy or open craniotomy thereby suggesting that clinical decisions may be based on the molecular profile of the tumor samples obtained via stereotactic biopsy.

Non-instrumented extradural lumbar spine surgery under low-dose acetylsalicylic acid: a comparative risk analysis study.

PURPOSE: Coronary artery disease (CAD) affects over one-third of adults and is the leading cause of overall mortality and morbidity. Acetylsalicylic acid (ASA) is widely used in the prevention of CAD. As the population continues to mature, the number of patients presenting for spinal surgery that are under ASA treatment is rising. Studies investigating the outcome of lumbar spine surgeries without discontinuation of ASA therapy are lacking. The purpose of this study is to evaluate the peri- and postoperative bleeding and cardiovascular complication rates of patients undergoing non-instrumented, extradural, lumbar spine surgery with or without discontinuation of low-dose ASA. METHODS: We retrospectively compared the intra- and postoperative blood loss, morbidity, mortality, blood transfusion requirements and hematologic findings in the ASA group (40 patients) and the control group (62 patients). The diagnosis in all patients was either lumbar disc herniation or spinal canal stenosis. RESULTS: Intraoperative blood loss was 221 ml in the ASA group and 140.16 ml in the control group, showing no statistical difference (p = 0.08). Postoperative blood loss was 146.58 and 167.97 ml in the ASA and control groups, respectively, also without statistical difference (p = 0.76). In the ASA group one patient developed a postoperative epidural hematoma needing revision surgery, while in the control group no postoperative epidural hematomas were seen (p = 0.40). In addition, blood transfusion requirements, hematologic findings, morbidity and mortality showed no significant difference. CONCLUSION: The continuation of ASA treatment in patients undergoing non-instrumented extradural lumbar spinal surgery seems to be safe and its perioperative continuation might therefore be recommended. Further studies confirming these results are needed.

Tumour necrosis factor receptor superfamily member 9 (TNFRSF9) is up-regulated in reactive astrocytes in human gliomas.

AIMS: The prognosis of patients with malignant gliomas is still dismal despite maximum treatment. Novel therapeutic alternatives targeting tumorigenic pathways are, therefore, demanded. In murine glioma models, targeting of tumour necrosis factor receptor superfamily (TNFRSF) 9 led to complete tumour eradication. Thus, TNFRSF9 might also constitute a promising target in human diffuse gliomas. As there is a lack of data, we aimed to define the expression pattern and cellular source of TNFRSF9 in human gliomas. METHODS: We investigated TNFRSF9 expression in normal human central nervous system (CNS) tissue and glioma specimens using immunohistochemistry, immunofluorescence and Western blotting techniques. RESULTS: Our results show that TNFRSF9 is considerably up-regulated in human gliomas when compared with normal brain tissue. In addition, our data provides evidence for an immune cell-independent de novo expression pattern of TNFRSF9 in mainly non-neoplastic reactive astrocytes and excludes classic immunological cell types, namely lymphocytes and microglia as the source of TNFRSF9. Moreover, TNFRSF9 is predominantly expressed in a perivascular and peritumoural distribution with significantly higher expression in IDH-1 mutant gliomas. CONCLUSIONS: Our findings provide a novel, TNFRSF9-positive, reactive astrocytic phenotype and challenge the therapeutic suitability of TNFRSF9 as a promising target for human gliomas.