Investigating the effects of arginine methylation inhibitors on microdissected brain tumour biopsies maintained in a miniaturised perfusion system.

Arginine methylation is a post-translational modification that consists of the transfer of one or two methyl (CH3) groups to arginine residues in proteins. Several types of arginine methylation occur, namely monomethylation, symmetric dimethylation and asymmetric dimethylation, which are catalysed by different protein arginine methyltransferases (PRMTs). Inhibitors of PRMTs have recently entered clinical trials to target several types of cancer, including gliomas (NCT04089449). People with glioblastoma (GBM), the most aggressive form of brain tumour, are among those with the poorest quality of life and likelihood of survival of anyone diagnosed with cancer. There is currently a lack of (pre)clinical research on the possible application of PRMT inhibitors to target brain tumours. Here, we set out to investigate the effects of clinically-relevant PRMT inhibitors on GBM biopsies. We present a new, low-cost, easy to fabricate perfusion device that can maintain GBM tissue in a viable condition for at least eight days post-surgical resection. The miniaturised perfusion device enables the treatment of GBM tissue with PRMT inhibitors ex vivo, and we observed a two-fold increase in apoptosis in treated samples compared to parallel control experiments. Mechanistically, we show thousands of differentially expressed genes after treatment, and changes in the type of arginine methylation of the RNA binding protein FUS that are consistent with hundreds of differential gene splicing events. This is the first time that cross-talk between different types of arginine methylation has been observed in clinical samples after treatment with PRMT inhibitors.

Prognostic factors following resection of intracranial metastases.

Background: The aim of this study was to identify prognostic factors associated with resection of intracranial metastases. Methods: A retrospective case series including patients who underwent resection of cranial metastases from March 2014 to April 2021 at a single center. This identified 112 patients who underwent 124 resections. The median age was 65 years old (24-84) and the most frequent primary cancers were nonsmall cell lung cancer (56%), breast adenocarcinoma (13%), melanoma (6%), and colorectal adenocarcinoma (6%). Postoperative MRI with contrast was performed within 48 hours in 56% of patients and radiation treatment was administered in 41%. GraphPad Prism 9.2.0 was used for the survival analysis. Results: At the time of data collection, 23% were still alive with a median follow-up of 1070 days (68-2484). The 30- and 90-day, and 1- and 5-year overall survival rates were 93%, 83%, 35%, and 17%, respectively. The most common causes of death within 90 days were as follows: unknown (32%), systemic or intracranial disease progression (26%), and pneumonia (21%). Age and extent of neurosurgical resection were associated with overall survival (P < 0.05). Patients aged >70 had a median survival of 5.4 months compared with 9.7, 11.4, and 11.4 for patients <50, 50-59, and 60-69, respectively. Gross-total resection achieved an overall survival of 11.8 months whereas sub-total, debulking, and unclear extent of resection led to a median survival of 5.7, 7.0, and 9.0 months, respectively. Conclusion: Age and extent of resection are potential predictors of long-term survival.

Pineal cyst surveillance in adults - a review of 10 years' experience.

Objective: Pineal cysts are common benign incidental findings in adults. There are no commonly accepted criteria for follow up or indications for intervention. We looked at our outcomes for this condition to explore their natural history and review our surveillance criteria.Method: Retrospective review of multidisciplinary team meetings at a tertiary neurosurgical centre over 10 years. Data relating to demographics, presenting symptoms, maximum diameter, duration of surveillance, final diagnosis and overall outcome were extracted from electronic patient records and available MRI. Data were analysed using IBM SPSS version 24.Result: Seventy-seven pineal cysts were identified. Female to male ratio was 1.43, female mean age was 38.6 and male mean age was 50.4. An increase in referral frequency was observed over the study period (mean increase of 1.4 cases per year). Presenting symptoms of headache in 45% and visual and hearing symptoms in 38.5% were recorded and baseline mean maximum diameter was 13.4mm. 20 patients were discharged on presentation, 54 were booked for at least one follow-up scan with a median follow up period of 14 months. The mean change in maximum diameter was 0.04mm over 18 months. Three patients (3.9%) underwent endoscopic biopsy and CSF diversion for cysts all more than 20mm with radiological evidence of hydrocephalus. In 100% of cases, the initial MDT diagnosis and final diagnosis were concordant.Conclusions: No patient under surveillance required surgical treatment and those managed surgically were symptomatic with large cysts and hydrocephalus on presentation. A majority of pineal cysts remained unchanged during the MRI follow-up, therefore our review suggests that routine follow-up of pineal cysts is not necessary in the absence of unusual radiological characteristics or related clinical symptoms.

Development of a Microfluidic Culture Paradigm for Ex Vivo Maintenance of Human Glioblastoma Tissue: A New Glioblastoma Model?

BACKGROUND: One way to overcome the genetic and molecular variations within glioblastoma is to treat each tumour on an individual basis. To facilitate this, we have developed a microfluidic culture paradigm that maintains human glioblastoma tissue ex vivo. METHODS: The assembled device, fabricated using a photolithographic process, is composed of two layers of glass bonded together to contain a tissue chamber and a network of microchannels that allow continued tissue perfusion. RESULTS: A total of 128 tissue biopsies (from 33 patients) were maintained in microfluidic devices for an average of 72 hours. Tissue viability (measured with Annexin V and propidium iodide) was 61.1% in tissue maintained on chip compared with 68.9% for fresh tissue analysed at commencement of the experiments. Other biomarkers, including lactate dehydrogenase absorbance and trypan blue exclusion, supported the viability of the tissue maintained on chip. Histological appearances remained unchanged during the tissue maintenance period, and immunohistochemical analysis of Ki67 and caspase 3 showed no significant differences when compared with fresh tissues. A trend showed that tumours associated with poorer outcomes (recurrent tumours and Isocitrate Dehydrogenase - IDH wildtype) displayed higher viability on chip than tumours linked with improved outcomes (low-grade gliomas, IDH mutants and primary tumours). CONCLUSIONS: This work has demonstrated for the first time that human glioblastoma tissue can be successfully maintained within a microfluidic device and has the potential to be developed as a new platform for studying the biology of brain tumours, with the long-term aim of replacing current preclinical GBM models and facilitating personalised treatments.

Cranial subarachnoid and subdural haemorrhage caused by spinal melanoma metastasis.

A 73-year-old female with a history of metastatic melanoma presented with extensive intracranial subarachnoid haemorrhage. Cranial imaging failed to reveal any vascular anomaly or tumour. MRI of the neuroaxis revealed a melanoma metastasis at T10 with associated subarachnoid haemorrhage. We review the literature on this rare presentation of subarachnoid haemorrhage.

Management of elderly patients with glioblastoma-multiforme-a systematic review.

The management of elderly patients with glioblastoma-multiforme (GBM) remains poorly defined with many experts in the past advocating best supportive care, in view of limited evidence on efficacy of more aggressive treatment protocols. There is randomised evidence (NORDIC and NA-O8 studies) to support the use of surgery followed by adjuvant monotherapy with either radiotherapy (RT) using hypofractionated regimes (e.g. 36 Gy in 6 fractions OR 40 Gy in 15 fractions) or chemotherapy with temozolomide (TMZ) in patients expressing methylation of promoter for O6-methylguanine-DNA methyltransferase enzyme. However, the role of combined-modality therapy involving the use of combined RT and TMZ protocols has remained controversial with data from the EORTC (European Organisation for Research and Treatment of Cancer)-NCIC (National Cancer Institute of Canada) studies indicating that patients more than 65 years of age may not benefit significantly from combining standard RT fractionation using 60 Gy in 30 fractions with concurrent and adjuvant TMZ. More recently, randomised data has emerged on combining hypofractionated RT with concurrent and adjuvant TMZ. We provide a comprehensive review of literature with the aim of defining an evidence-based algorithm for management of elderly glioblastoma-multiforme population.

Isoniazid-resistant intracranial tuberculoma treated with a combination of moxifloxacin and first-line anti-tuberculosis medication.

We report a case of a previously healthy 23-year-old Somalian care assistant. She presented with a 4 month history of persistent occipital headaches associated with intermittent nausea and vomiting. Computed tomography and magnetic resonance imaging of the brain showed a large enhancing lesion in the right cerebellar hemisphere with surrounding ring lesions, suggestive of an intracranial neoplasm with metastases. However, tuberculoma of the brain was confirmed based on histology of the excision biopsy and cerebrospinal fluid (CSF) culture results: Mycobacterium tuberculosis resistant to isoniazid (INH) with sensitivity to other standard drugs, including fluoroquinolones, was cultured from CSF. No primary focus to suggest spread from elsewhere was found. The patient was treated successfully with moxifloxacin, rifampicin, pyrazinamide and ethambutol. Isolated INH-resistant intracranial tuberculoma is rare in adults. It can mimic other intracranial masses and should be kept in mind, especially in populations with a high risk of tuberculosis. Clinical use of moxifloxacin in INH-resistant tuberculomas is limited in humans and this case demonstrates that moxifloxacin may be an effective alternative treatment.

The sequential use of carmustine wafers (Gliadel®) and post-operative radiotherapy with concomitant temozolomide followed by adjuvant temozolomide: a clinical review.

In patients with glioblastoma multiforme (GBM), there is no consensus on the sequential use of two existing regimens: post-operative Gliadel implantation into the surgical cavity and concomitant temozolomide with radiotherapy followed by adjuvant temozolomide ('Stupp protocol'). NICE in the guideline TA121 (July 2007) could not pass any judgement on the sequential use of both the regimens due to lack of evidence at the time of consultation. Since then, few prospective studies and retrospective series have been reported using these two regimens sequentially. Except in one study, results were indicative of an incremental gain of 2-3 months in median survival in comparison to the published results using Gliadel or 'Stupp Protocol' alone. Post-surgical complications were manageable and within an acceptable range, when the sequential regimen was managed under defined guidelines and surgery was performed in a high volume centre. Moderate degree of increased myelosuppression has been reported in few series, however. In the absence of a phase III trial and the small number of patients in each series, the reported trend of toxicities and efficacy could only be substantiated by setting up a national database. Contributing to such a national database and toxicity recording could be made mandatory through peer review programme for the neurooncological services. Based on the preclinical and albeit lower level of clinical evidence, demonstrating temporal and spatial co-operation between two regimens (Gliadel and 'Stupp Protocol'), resulting in incremental 2-3 months median survival gain, should enable NICE in its next review to issue a favourable guidance. Depending on the number of patients eligible for such a sequential regimen, which could be 15%-25% of Glioblastoma patients diagnosed in England per annum, the additional annual cost of concomitant temozolomide would be approximately £640,000 to £1 million.