Toward standardized brain tumor tissue processing protocols in neuro-oncology: a perspective for gliomas and beyond.

Implementation of standardized protocols in neurooncology during the surgical resection of brain tumors is needed to advance the clinical treatment paradigms that use tissue for diagnosis, prognosis, bio-banking, and treatment. Currently recommendations on intraoperative tissue procurement only exist for diffuse gliomas but management of other brain tumor subtypes can also benefit from these protocols. Fresh tissue from surgical resection can now be used for intraoperative diagnostics and functional precision medicine assays. A multidisciplinary neuro-oncology perspective is critical to develop the best avenues for practical standardization. This perspective from the multidisciplinary Oncology Tissue Advisory Board (OTAB) discusses current advances, future directions, and the imperative of adopting standardized protocols for diverse brain tumor entities. There is a growing need for consistent operating room practices to enhance patient care, streamline research efforts, and optimize outcomes.

Impact of upfront adjuvant chemoradiation on survival in patients with molecularly defined oligodendroglioma: the benefits of PCV over TMZ.

PURPOSE: Oligodendroglioma is an adult-type diffuse glioma defined by 1p/19q codeletion and IDH1/2 mutation. Treatment includes surgery followed by observation alone in select low-grade tumors, or combination radiation and chemotherapy with procarbazine, lomustine, and vincristine (PCV) or temozolomide (TMZ). While prospective studies investigating treatments for molecularly defined oligodendrogliomas are ongoing, this retrospective study analyzes the relationship between adjuvant regimens and progression-free survival (PFS). METHODS: Adults with IDH-mutant, 1p/19q codeleted oligodendroglioma (WHO grade 2 or 3) who underwent surgery between 2005 and 2021 were identified. Clinical data, disease characteristics, treatment, and outcomes were collected. RESULTS: A total of 207 patients with grade 2 and 70 with grade 3 oligodendrogliomas were identified. Median (IQR) follow-up was 57 (87) months. Patients with grade 3 tumors who received adjuvant radiation and PCV had longer median PFS (> 110 months) than patients who received radiation and TMZ (52 months, p = 0.008) or no adjuvant chemoradiation (83 months, p = 0.03), which was not seen in grade 2 tumors (p = 0.8). In multivariate analysis, patients who received PCV chemotherapy (Relative Risk [95% CI] = 0.24[0.05-1.08] and radiotherapy (0.46[0.21-1.02]) trended towards longer PFS, independently of grade. CONCLUSION: Adjuvant radiation and PCV are associated with improved PFS over radiation with TMZ in patients with grade 3 molecularly defined oligodendrogliomas, and all-grade patients treated with PCV trended towards decreased risk of recurrence and progression. These results highlight the importance of ongoing clinical trials investigating these treatments.

Evaluating the atherosclerosis cardiovascular disease risk score in patients with brain metastases: Associations with overall survival and high-value care outcomes.

OBJECTIVE: Brain metastases (BM) constitute the most common intracranial tumor in adults. Prior literature indicates the 10-year atherosclerotic cardiovascular disease (ASCVD) risk score is associated with increased risk of cancer, potentially attributable to shared risk factors. Understanding the role of ASCVD risk scores in BM may help optimize their care and inform clinical decision-making. Our aim was to explore associations between ASCVD risk score in BM patients and their overall survival, hospital charges, and non-routine discharge disposition. METHODS: Electronic medical records were reviewed to collect clinical data for BM patients undergoing surgery at a single institution (2017-2021). Regression analyses were performed accordingly and maximally selected rank statistics were employed to identify an optimal cutoff for ASCVD risk scores. The random survival forest (RSF) machine learning technique identified the most important variable associated with survival outcomes in BM patients. RESULTS: A total of 139 patients were included with average age 62.93±9.29 years, 48.2 % male, 25.2 % with high hospital charges, and 23.7 % experiencing non-routine discharge. Among these patients, 32.3 % had prior history of an ASCVD event, while 67.7 % did not. Overall, this cohort had an average 10-year ASCVD risk score of 12.51±12.98, indicating intermediate risk of ASCVD among all BM patients. On multivariate logistic regression, prior history of ASCVD was associated with higher odds of high hospital charges (OR=3.670, p=0.018), and higher ASCVD risk scores were associated with greater odds of non-routine discharge (OR=1.059, p=0.012). On the multivariate Cox regression model, higher ASCVD risk scores correlated with worse overall survival (HR=1.031, p=0.014). A threshold of 25.1 was identified for high-risk ASCVD scores. Patients with ASCVD scores >25.1 exhibited reduced overall survival in Kaplan-Meier analysis (p=0.015) and multivariate Cox regression (HR: 2.811, p=0.016). Notably, ASCVD risk scores were found to be the most important variable in predicting worse survival outcomes in BM patients compared to other established frailty indices. CONCLUSION: This study indicates higher ASCVD risk scores in BM patients are associated with worse overall survival. Integrating ASCVD assessment into clinical workflow may facilitate more informed risk-based decision-making.

The CCR6-CCL20 axis promotes regulatory T cell glycolysis and immunosuppression in tumors.

Regulatory T cells (Tregs) are important players in the tumor microenvironment. However, the mechanisms behind their immunosuppressive effects are poorly understood. We found that CCR6-CCL20 activity in tumor-infiltrating Tregs is associated with greater glycolytic activity and ablation of Ccr6 reduced glycolysis and lactic acid production while increasing compensatory glutamine metabolism. Immunosuppressive activity towards CD8+ T cells was abrogated in Ccr6-/- Tregs due to reduction in activation-induced glycolysis. Furthermore, Ccr6-/- mice exhibited improved survival across multiple tumor models compared to wildtype mice, and Treg and CD8+ T-cell depletion abrogated the improvement. In addition, Ccr6 ablation further promoted the efficacy of anti-PD-1 therapy in a preclinical glioma model. Follow-up knockdown of Ccl20 with siRNA also demonstrated improvement in antitumor efficacy. Our results unveil CCR6 as a marker and regulator of Treg-induced immunosuppression and identify approaches to target the metabolic determinants of Treg immunosuppressive activity.

The cytokine Meteorin-like inhibits anti-tumor CD8+ T cell responses by disrupting mitochondrial function.

Tumor-infiltrating lymphocyte (TIL) hypofunction contributes to the progression of advanced cancers and is a frequent target of immunotherapy. Emerging evidence indicates that metabolic insufficiency drives T cell hypofunction during tonic stimulation, but the signals that initiate metabolic reprogramming in this context are largely unknown. Here, we found that Meteorin-like (METRNL), a metabolically active cytokine secreted by immune cells in the tumor microenvironment (TME), induced bioenergetic failure of CD8+ T cells. METRNL was secreted by CD8+ T cells during repeated stimulation and acted via both autocrine and paracrine signaling. Mechanistically, METRNL increased E2F-peroxisome proliferator-activated receptor delta (PPARδ) activity, causing mitochondrial depolarization and decreased oxidative phosphorylation, which triggered a compensatory bioenergetic shift to glycolysis. Metrnl ablation or downregulation improved the metabolic fitness of CD8+ T cells and enhanced tumor control in several tumor models, demonstrating the translational potential of targeting the METRNL-E2F-PPARδ pathway to support bioenergetic fitness of CD8+ TILs.

Genomic Alterations in Molecularly Defined Oligodendrogliomas.

BACKGROUND AND OBJECTIVES: Oligodendrogliomas are defined by IDH1/2 mutation and codeletion of chromosome arms 1p/19q. Although previous studies identified CIC, FUBP1, and TERTp as frequently altered in oligodendrogliomas, the clinical relevance of these molecular signatures is unclear. Moreover, previous studies predominantly used research panels that are not readily available to providers and patients. Accordingly, we explore genomic alterations in molecularly defined oligodendrogliomas using clinically standardized next-generation sequencing (NGS) panels. METHODS: A retrospective single-center study evaluated adults with pathologically confirmed IDH-mutant, 1p/19q-codeleted oligodendrogliomas diagnosed between 2005 and 2021. Genetic data from formalin-fixed, paraffin-embedded specimens were analyzed with the NGS Solid Tumor Panel at the Johns Hopkins Medical Laboratories, which tests more than 400 cancer-related genes. Kaplan-Meier plots and log-rank tests compared progression-free survival (PFS) and overall survival by variant status. χ2 tests, t-tests, and Wilcoxon rank-sum tests were used to compare clinical characteristics between genomic variant status in the 10 most frequently altered genes. RESULTS: Two hundred and seventy-seven patients with molecularly defined oligodendrogliomas were identified, of which 95 patients had available NGS reports. Ten genes had 9 or more patients with a genomic alteration, with CIC, FUBP1, and TERTp being the most frequently altered genes (n = 60, 23, and 22, respectively). Kaplan-Meier curves showed that most genes were not associated with differences in PFS or overall survival. At earlier time points (PFS <100 months), CIC alterations conferred a reduction in PFS in patients (P = .038). CONCLUSION: Our study confirms the elevated frequency of CIC, FUBP1, and TERTp alterations in molecularly defined oligodendrogliomas and suggests a potential relationship of CIC alteration to PFS at earlier time points. Understanding these genomic variants may inform prognosis or therapeutic recommendations as NGS becomes routine.

Exploring the impact of primary care utilization and health information exchange upon treatment patterns and clinical outcomes of glioblastoma patients.

PURPOSE: There is limited literature describing care coordination for patients with glioblastoma (GBM). We aimed to investigate the impact of primary care and electronic health information exchange (HIE) between neurosurgeons, oncologists, and primary care providers (PCP) on GBM treatment patterns, postoperative outcomes, and survival. METHODS: We identified adult GBM patients undergoing primary resection at our institution (2007-2020). HIE was defined as shared electronic medical information between PCPs, oncologists, and neurosurgeons. Multivariate logistic regression analyses were used to determine the effect of PCPs and HIE upon initiation and completion of adjuvant therapy. Kaplan-Meier and multivariate Cox regression models were used to evaluate overall survival (OS). RESULTS: Among 374 patients (mean age ± SD: 57.7 ± 13.5, 39.0% female), 81.0% had a PCP and 62.4% had electronic HIE. In multivariate analyses, having a PCP was associated with initiation (OR: 7.9, P < 0.001) and completion (OR: 4.4, P < 0.001) of 6 weeks of concomitant chemoradiation, as well as initiation (OR: 4.0, P < 0.001) and completion (OR: 3.0, P = 0.007) of 6 cycles of maintenance temozolomide thereafter. Having a PCP (median OS [95%CI]: 14.6[13.1-16.1] vs. 10.8[8.2-13.3] months, P = 0.005) and HIE (15.40[12.82-17.98] vs. 13.80[12.51-15.09] months, P = 0.029) were associated with improved OS relative to counterparts in Kaplan-Meier analysis and in multivariate Cox regression analysis (hazard ratio [HR] = 0.7, [95% CI] 0.5-1.0, P = 0.048). In multivariate analyses, chemoradiation (HR = 0.34, [95% CI] 0.2-0.7, P = 0.002) and maintenance temozolomide (HR = 0.5, 95%CI 0.3-0.8, P = 0.002) were associated with improved OS relative to counterparts. CONCLUSION: Effective care coordination between neurosurgeons, oncologists, and PCPs may offer a modifiable avenue to improve GBM outcomes.

CCR2 and CCR5 co-inhibition modulates immunosuppressive myeloid milieu in glioma and synergizes with anti-PD-1 therapy.

Immunotherapy has revolutionized the treatment of cancers. Reinvigorating lymphocytes with checkpoint blockade has become a cornerstone of immunotherapy for multiple tumor types, but the treatment of glioblastoma has not yet shown clinical efficacy. A major hurdle to treat GBM with checkpoint blockade is the high degree of myeloid-mediated immunosuppression in brain tumors that limits CD8 T-cell activity. A potential strategy to improve anti-tumor efficacy against glioma is to use myeloid-modulating agents to target immunosuppressive cells, such as myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. We found that the co-inhibition of the chemokine receptors CCR2 and CCR5 in murine model of glioma improves the survival and synergizes robustly with anti-PD-1 therapy. Moreover, the treatment specifically reduced the infiltration of monocytic-MDSCs (M-MDSCs) into brain tumors and increased lymphocyte abundance and cytokine secretion by tumor-infiltrating CD8 T cells. The depletion of T-cell subsets and myeloid cells abrogated the effects of CCR2 and CCR5 blockade, indicating that while broad depletion of myeloid cells does not improve survival, specific reduction in the infiltration of immunosuppressive myeloid cells, such as M-MDSCs, can boost the anti-tumor immune response of lymphocytes. Our study highlights the potential of CCR2/CCR5 co-inhibition in reducing myeloid-mediated immunosuppression in GBM patients.

The Hospital Frailty Risk Score Independently Predicts Postoperative Outcomes in Glioblastoma Patients.

OBJECTIVE: The Hospital Frailty Risk Score (HFRS) is a tool for quantifying patient frailty using International Classification of Diseases, Tenth Revision codes. This study aimed to determine the utility of the HFRS in predicting surgical outcomes after resection of glioblastoma (GBM) and compare its prognostic ability with other validated indices such as American Society of Anesthesiologists score and Charlson Comorbidity Index. METHODS: A retrospective analysis was conducted using a GBM patient database (2017-2019) at a single institution. HFRS was calculated using International Classification of Diseases, Tenth Revision codes. Bivariate logistic regression was used to model prognostic ability of each frailty index, and model discrimination was assessed using area under the receiver operating characteristic curve. Multivariate linear and logistic regression models were used to assess for significant associations between HFRS and continuous and binary postoperative outcomes, respectively. RESULTS: The study included 263 patients with GBM. The HFRS had a significantly greater area under the receiver operating characteristic curve compared with American Society of Anesthesiologists score (P = 0.016) and Charlson Comorbidity Index (P = 0.037) for predicting 30-day readmission. On multivariate analysis, the HFRS was significantly and independently associated with hospital length of stay (P = 0.0038), nonroutine discharge (P = 0.018), and 30-day readmission (P = 0.0051). CONCLUSIONS: The HFRS has utility in predicting postoperative outcomes for patients with GBM and more effectively predicts 30-day readmission than other frailty indices. The HFRS may be used as a tool for optimizing clinical decision making to reduce adverse postoperative outcomes in patients with GBM.

GPR68-ATF4 signaling is a novel prosurvival pathway in glioblastoma activated by acidic extracellular microenvironment.

BACKGROUND: Glioblastoma multiforme (GBM) stands as a formidable challenge in oncology because of its aggressive nature and severely limited treatment options. Despite decades of research, the survival rates for GBM remain effectively stagnant. A defining hallmark of GBM is a highly acidic tumor microenvironment, which is thought to activate pro-tumorigenic pathways. This acidification is the result of altered tumor metabolism favoring aerobic glycolysis, a phenomenon known as the Warburg effect. Low extracellular pH confers radioresistant tumors to glial cells. Notably GPR68, an acid sensing GPCR, is upregulated in radioresistant GBM. Usage of Lorazepam, which has off target agonism of GPR68, is linked to worse clinical outcomes for a variety of cancers. However, the role of tumor microenvironment acidification in GPR68 activation has not been assessed in cancer. Here we interrogate the role of GPR68 specifically in GBM cells using a novel highly specific small molecule inhibitor of GPR68 named Ogremorphin (OGM) to induce the iron mediated cell death pathway: ferroptosis. METHOD: OGM was identified in a non-biased zebrafish embryonic development screen and validated with Morpholino and CRISPR based approaches. Next, A GPI-anchored pH reporter, pHluorin2, was stably expressed in U87 glioblastoma cells to probe extracellular acidification. Cell survival assays, via nuclei counting and cell titer glo, were used to demonstrate sensitivity to GPR68 inhibition in twelve immortalized and PDX GBM lines. To determine GPR68 inhibition's mechanism of cell death we use DAVID pathway analysis of RNAseq. Our major indication, ferroptosis, was then confirmed by western blotting and qRT-PCR of reporter genes including TFRC. This finding was further validated by transmission electron microscopy and liperfluo staining to assess lipid peroxidation. Lastly, we use siRNA and CRISPRi to demonstrate the critical role of ATF4 suppression via GPR68 for GBM survival. RESULTS: We used a pHLourin2 probe to demonstrate how glioblastoma cells acidify their microenvironment to activate the commonly over expressed acid sensing GPCR, GPR68. Using our small molecule inhibitor OGM and genetic means, we show that blocking GPR68 signaling results in robust cell death in all thirteen glioblastoma cell lines tested, irrespective of genetic and phenotypic heterogeneity, or resistance to the mainstay GBM chemotherapeutic temozolomide. We use U87 and U138 glioblastoma cell lines to show how selective induction of ferroptosis occurs in an ATF4-dependent manner. Importantly, OGM was not-acutely toxic to zebrafish and its inhibitory effects were found to spare non-malignant neural cells. CONCLUSION: These results indicate GPR68 emerges as a critical sensor for an autocrine pro-tumorigenic signaling cascade triggered by extracellular acidification in glioblastoma cells. In this context, GPR68 suppresses ATF4, inhibition of GPR68 increases expression of ATF4 which leads to ferroptotic cell death. These findings provide a promising therapeutic approach to selectively induce ferroptosis in glioblastoma cells while sparing healthy neural tissue.

Soluble PD-L1 reprograms blood monocytes to prevent cerebral edema and facilitate recovery after ischemic stroke.

Acute cerebral ischemia triggers a profound inflammatory response. While macrophages polarized to an M2-like phenotype clear debris and facilitate tissue repair, aberrant or prolonged macrophage activation is counterproductive to recovery. The inhibitory immune checkpoint Programmed Cell Death Protein 1 (PD-1) is upregulated on macrophage precursors (monocytes) in the blood after acute cerebrovascular injury. To investigate the therapeutic potential of PD-1 activation, we immunophenotyped circulating monocytes from patients and found that PD-1 expression was upregulated in the acute period after stroke. Murine studies using a temporary middle cerebral artery (MCA) occlusion (MCAO) model showed that intraperitoneal administration of soluble Programmed Death Ligand-1 (sPD-L1) significantly decreased brain edema and improved overall survival. Mice receiving sPD-L1 also had higher performance scores short-term, and more closely resembled sham animals on assessments of long-term functional recovery. These clinical and radiographic benefits were abrogated in global and myeloid-specific PD-1 knockout animals, confirming PD-1+ monocytes as the therapeutic target of sPD-L1. Single-cell RNA sequencing revealed that treatment skewed monocyte maturation to a non-classical Ly6Clo, CD43hi, PD-L1+ phenotype. These data support peripheral activation of PD-1 on inflammatory monocytes as a therapeutic strategy to treat neuroinflammation after acute ischemic stroke.

Management and Molecular Characterization of Intraventricular Glioblastoma: A Single-Institution Case Series.

While the central nervous system (CNS) tumor classification has increasingly incorporated molecular parameters, there is a paucity of literature reporting molecular alterations found in intraventricular glioblastoma (IVGBM), which are rare. We present a case series of nine IVGBMs, including molecular alterations found in standardized next-generation sequencing (NGS). We queried the clinical charts, operative notes, pathology reports, and radiographic images of nine patients with histologically confirmed IVGBM treated at our institution (1995-2021). Routine NGS was performed on resected tumor tissue of two patients. In this retrospective case series of nine patients (22% female, median (range) age: 64.3 (36-85) years), the most common tumor locations were the atrium of the right lateral ventricle (33%) and the septum pellucidum (33%). Five patients had preoperative hydrocephalus, which was managed with intraoperative external ventricular drains in three patients and ventriculoperitoneal shunts in one patient. Hydrocephalus was managed with subtotal resection of a fourth ventricular IVGBM in one patient. The most common surgical approach was transcortical intraventricular (56%). Gross total resection was achieved in two patients, subtotal resection was achieved in six patients, and one patient received a biopsy only. Immunohistochemistry for IDH1 R132H mutant protein was performed in four cases and was negative in all four. Genetic alterations common in glioblastoma, IDH-wildtype, were seen in two cases with available NGS data, including EGFR gene amplification, TERT promoter mutation, PTEN mutation, trisomy of chromosome 7, and monosomy of chromosome 10. Following surgical resection, four patients received adjuvant chemoradiation. Median survival among our cohort was 4.7 months (IQR: 0.9-5.8 months). Management of IVGBM is particularly challenging due to their anatomical location, presentation with obstructive hydrocephalus, and fast growth, necessitating prompt intervention. Additional studies are needed to better understand the genetic landscape of IVGBM compared to parenchymal glioblastoma and may further elucidate the unique pathophysiology of these rare tumors.

The mFI-5 and Postoperative Outcomes in Brain Tumor Patients: A Bayesian Approach to Quantifying Uncertainty.

OBJECTIVE: To the best of our knowledge, prior research has not investigated the uncertainty in the relationship between patient frailty and postoperative outcomes after brain tumor surgery. The present study used Bayesian methods to quantify the statistical uncertainty between the 5-factor modified frailty index (mFI-5) and postoperative outcomes for patients undergoing brain tumor resection. METHODS: The present study used retrospective data collected from patients undergoing brain tumor resection during a 2-year period (2017-2019). Posterior probability distributions were used to estimate the means of model parameters that are most likely given the priors and the data. Additionally, 95% credible intervals (CrIs) were constructed for each parameter estimate. RESULTS: Our patient cohort included 2519 patients with a mean age of 55.27 years. Our multivariate analysis demonstrated that each 1-point increase in the mFI-5 score was associated with an 18.76% (95% CrI, 14.35%-23.36%) increase in hospital length of stay and a 9.37% (CrI, 6.82%-12.07%) increase in hospital charges. We also noted an association between an increasing mFI-5 score and greater odds of a postoperative complication (odds ratio [OR], 1.58; CrI, 1.34-1.87) and a nonroutine discharge (OR, 1.54; CrI, 1.34-1.80). However, no meaningful statistical association was found between the mFI-5 score and 90-day hospital readmission (OR, 1.16; CrI, 0.98-1.36) or between the mFI-5 score and 90-day mortality (OR, 1.12; CrI, 0.83-1.50). CONCLUSIONS: Although mFI-5 scores might be able to effectively predict short-term outcomes such as length of stay, our results demonstrate no meaningful association between mFI-5 scores and 90-day readmission or 90-day mortality. Our study highlights the need for rigorously quantifying statistical uncertainty to safely risk-stratify neurosurgical patients.

An asynchronous web-based intervention for neurosurgery residents to improve education on cost-effective care.

OBJECTIVE: To gauge resident knowledge in the socioeconomic aspects of neurosurgery and assess the efficacy of an asynchronous, longitudinal, web-based, socioeconomics educational program tailored for neurosurgery residents. METHODS: Trainees completed a 20-question pre- and post-intervention knowledge examination including four educational categories: billing/coding, procedure-specific concepts, material costs, and operating room protocols. Structured data from 12 index cranial neurosurgical operations were organized into 5 online, case-based modules sent to residents within a single training program via weekly e-mail. Content from each educational category was integrated into the weekly modules for resident review. RESULTS: Twenty-seven neurosurgical residents completed the survey. Overall, there was no statistically significant difference between pre- vs post-intervention resident knowledge of billing/coding (79.2 % vs 88.2 %, p = 0.33), procedure-specific concepts (34.3 % vs 39.2 %, p = 0.11), material costs (31.7 % vs 21.6 %, p = 0.75), or operating room protocols (51.7 % vs 35.3 %, p = 0.61). However, respondents' accuracy increased significantly by 40.8 % on questions containing content presented more than 3 times during the 5-week study period, compared to an increased accuracy of only 2.2 % on questions containing content presented less often during the same time period (p = 0.05). CONCLUSIONS: Baseline resident knowledge in socioeconomic aspects of neurosurgery is relatively lacking outside of billing/coding. Our socioeconomic educational intervention demonstrates some promise in improving socioeconomic knowledge among neurosurgery trainees, particularly when content is presented frequently. This decentralized, web-based approach to resident education may serve as a future model for self-driven learning initiatives among neurosurgical residents with minimal disruption to existing workflows.

Deoxyhypusine hydroxylase: A novel therapeutic target differentially expressed in short-term vs long-term survivors of glioblastoma.

Glioblastoma (GB) is the most aggressive neoplasm of the brain. Poor prognosis is mainly attributed to tumor heterogeneity, invasiveness and drug resistance. Only a small fraction of GB patients survives longer than 24 months from the time of diagnosis (ie, long-term survivors [LTS]). In our study, we aimed to identify molecular markers associated with favorable GB prognosis as a basis to develop therapeutic applications to improve patients' outcome. We have recently assembled a proteogenomic dataset of 87 GB clinical samples of varying survival rates. Following RNA-seq and mass spectrometry (MS)-based proteomics analysis, we identified several differentially expressed genes and proteins, including some known cancer-related pathways and some less established that showed higher expression in short-term (<6 months) survivors (STS) compared to LTS. One such target found was deoxyhypusine hydroxylase (DOHH), which is known to be involved in the biosynthesis of hypusine, an unusual amino acid essential for the function of the eukaryotic translation initiation factor 5A (eIF5A), which promotes tumor growth. We consequently validated DOHH overexpression in STS samples by quantitative polymerase chain reaction (qPCR) and immunohistochemistry. We further showed robust inhibition of proliferation, migration and invasion of GB cells following silencing of DOHH with short hairpin RNA (shRNA) or inhibition of its activity with small molecules, ciclopirox and deferiprone. Moreover, DOHH silencing led to significant inhibition of tumor progression and prolonged survival in GB mouse models. Searching for a potential mechanism by which DOHH promotes tumor aggressiveness, we found that it supports the transition of GB cells to a more invasive phenotype via epithelial-mesenchymal transition (EMT)-related pathways.

Establishing proof of concept for sonolucent cranioplasty and point of care ultrasound imaging after posterior fossa decompression for Chiari malformation.

BACKGROUND: Evaluation after posterior fossa decompression for Chiari malformation can require repeated imaging, particularly with persistent symptoms. Typically, CT or MRI is used. However, CT carries radiation risk and MRI is costly. Ultrasound is an inexpensive, radiation-free, point-of-care modality that has, thus far, been limited by intact skull and traditional cranioplasty materials. Ultrasound also allows for imaging in different head positions and body postures, which may lend insight into cause for persistent symptoms despite adequate decompression on traditional neutral static CT or MRI. We evaluate safety and feasibility of ultrasound as a post-operative imaging modality in patients reconstructed with sonolucent cranioplasty during posterior fossa decompression for Chiari malformation. METHODS: Outcomes were analyzed for 26 consecutive patients treated with a Chiari-specific sonolucent cranioplasty. This included infection, need for revision, CSF leak, and pseudomeningocele. Ultrasound was performed point-of-care in the outpatient clinic by the neurosurgery team to assess feasibility. RESULTS: In eight months mean follow up, there were no surgical site infections or revisions with this novel sonolucent cranioplasty. Posterior fossa anatomy was discernable via transcutaneous ultrasound obtained point-of-care in the clinic setting at follow up visits. CONCLUSION: We demonstrate proof of concept for ultrasound as a post-operative imaging modality after posterior fossa decompression for Chiari malformation. With further investigation, ultrasound may prove to serve as an alternative to CT and MRI in this patient population, or as an adjunct to provide positional and dynamic information. Use of sonolucent cranioplasty is safe. This technique deserves further study.

Self-assembling paclitaxel-mediated stimulation of tumor-associated macrophages for postoperative treatment of glioblastoma.

The unique cancer-associated immunosuppression in brain, combined with a paucity of infiltrating T cells, contributes to the low response rate and poor treatment outcomes of T cell-based immunotherapy for patients diagnosed with glioblastoma multiforme (GBM). Here, we report on a self-assembling paclitaxel (PTX) filament (PF) hydrogel that stimulates macrophage-mediated immune response for local treatment of recurrent glioblastoma. Our results suggest that aqueous PF solutions containing aCD47 can be directly deposited into the tumor resection cavity, enabling seamless hydrogel filling of the cavity and long-term release of both therapeutics. The PTX PFs elicit an immune-stimulating tumor microenvironment (TME) and thus sensitizes tumor to the aCD47-mediated blockade of the antiphagocytic "don't eat me" signal, which subsequently promotes tumor cell phagocytosis by macrophages and also triggers an antitumor T cell response. As adjuvant therapy after surgery, this aCD47/PF supramolecular hydrogel effectively suppresses primary brain tumor recurrence and prolongs overall survivals with minimal off-target side effects.

First Experience With Postoperative Transcranial Ultrasound Through Sonolucent Burr Hole Covers in Adult Hydrocephalus Patients.

BACKGROUND: Managing patients with hydrocephalus and cerebrospinal fluid (CSF) disorders requires repeated head imaging. In adults, it is typically computed tomography (CT) or less commonly magnetic resonance imaging (MRI). However, CT poses cumulative radiation risks and MRI is costly. Ultrasound is a radiation-free, relatively inexpensive, and optionally point-of-care alternative, but is prohibited by very limited windows through an intact skull. OBJECTIVE: To describe our initial experience with transcutaneous transcranial ultrasound through sonolucent burr hole covers in postoperative hydrocephalus and CSF disorder patients. METHODS: Using cohort study design, infection and revision rates were compared between patients who underwent sonolucent burr hole cover placement during new ventriculoperitoneal shunt placement and endoscopic third ventriculostomy over the 1-year study time period and controls from the period 1 year before. Postoperatively, trans-burr hole ultrasound was performed in the clinic, at bedside inpatient, and in the radiology suite to assess ventricular anatomy. RESULTS: Thirty-seven patients with sonolucent burr hole cover were compared with 57 historical control patients. There was no statistically significant difference in infection rates between the sonolucent burr hole cover group (1/37, 2.7%) and the control group (0/57, P = .394). Revision rates were 13.5% vs 15.8% (P = 1.000), but no revisions were related to the burr hole or cranial hardware. CONCLUSION: Trans-burr hole ultrasound is feasible for gross evaluation of ventricular caliber postoperatively in patients with sonolucent burr hole covers. There was no increase in infection rate or revision rate. This imaging technique may serve as an alternative to CT and MRI in the management of select patients with hydrocephalus and CSF disorders.

Predictors of surgical site infection in glioblastoma patients undergoing craniotomy for tumor resection.

OBJECTIVE: Surgical site infections (SSIs) burden patients and healthcare systems, often requiring additional intervention. The objective of this study was to identify the relationship between preoperative predictors inclusive of scalp incision type and postoperative SSI following glioblastoma resection. METHODS: The authors retrospectively reviewed cases of glioblastoma resection performed at their institution from December 2006 to December 2019 and noted preoperative demographic and clinical presentations, excluding patients missing these data. Preoperative nutritional indices were available for a subset of cases. Scalp incisions were categorized as linear/curvilinear, reverse question mark, trapdoor, or frontotemporal. Patients were dichotomized by SSI incidence. Multivariable logistic regression was used to determine predictors of SSI. RESULTS: A total of 911 cases of glioblastoma resection were identified, 30 (3.3%) of which demonstrated postoperative SSI. There were no significant differences in preoperative malnutrition or number of surgeries between SSI and non-SSI cases. The SSI cases had a significantly lower preoperative Karnofsky Performance Status (KPS) than the non-SSI cases (63.0 vs 75.1, p < 0.0001), were more likely to have prior radiation history (43.3% vs 26.4%, p = 0.042), and were more likely to have received steroids both preoperatively and postoperatively (83.3% vs 54.5%, p = 0.002). Linear/curvilinear incisions were more common in non-SSI than in SSI cases (56.9% vs 30.0%, p = 0.004). Trapdoor scalp incisions were more frequent in SSI than non-SSI cases (43.3% vs 24.2%, p = 0.012). On multivariable analysis, a lower preoperative KPS (OR 1.04, 95% CI 1.02-1.06), a trapdoor scalp incision (OR 3.34, 95% CI 1.37-8.49), and combined preoperative and postoperative steroid administration (OR 3.52, 95% CI 1.41-10.7) were independently associated with an elevated risk of postoperative SSI. CONCLUSIONS: The study findings indicated that SSI risk following craniotomy for glioblastoma resection may be elevated in patients with a low preoperative KPS, a trapdoor scalp incision during surgery, and steroid treatment both preoperatively and postoperatively. These data may help guide future operative decision-making for these patients.

Patient Safety Indicator 04 Does Not Consistently Identify Failure to Rescue in the Neurosurgical Population.

BACKGROUND: Improving neurosurgical quality metrics necessitates the analysis of patient safety indicator (PSI) 04, a measure of failure to rescue (FTR). OBJECTIVE: To demonstrate that PSI 04 is not an appropriate measure for capturing FTR within neurosurgery. METHODS: We conducted a single-center retrospective cohort study. Patients from January 1, 2017 to June 1, 2021, who sustained a PSI 04-attributed complication (pneumonia, deep vein thrombosis/pulmonary embolism, sepsis, shock/cardiac arrest, or gastrointestinal hemorrhage/acute ulcer), underwent a neurosurgical procedure, had inpatient mortality, and were identified using patient safety indicator 04 (PSI 04) tracking algorithm. The primary outcome was whether the attributed PSI 04 designation was the primary driver of mortality. RESULTS: We identified 67 patients who met the PSI 04 criteria (median age, 61 years; female sex, 43.4%). Nearly 20% of patients met the PSI complication criteria before admission. Patients who underwent emergent bedside procedures were more likely to present with a poor Glasgow Coma Scale ( P = .016), more likely to be intubated before admission ( P = .016), and less likely to have mortality due to a PSI 04-related complication ( P = .002). PSI 04-related complications were identified as the cause of death in only 43.2% of cases. Procedures occurring in the interventional radiology suite (odds ratio, 23.2; 95% CI, 3.5-229.3; P = .003) or the operating room (odds ratio, 6.2; 95% CI, 1.25-39.5; P = .03) were more likely to have mortality because of a PSI 04-related complication compared with bedside procedures. CONCLUSION: In total, 65.7% of patients were inappropriately flagged as meeting PSI 04 criteria. PSI 04 currently identifies patients with complications unrelated to operating room procedures. Improvement in patient safety within neurosurgery necessitates the development of a subspecialty specific measure to capture FTR.