Peritumoral Brain Research Articles

In situ brain tumor detection using a Raman spectroscopy system—results of a multicenter study

Safe and effective brain tumor surgery aims to remove tumor tissue, not non-tumoral brain. This is a challenge since tumor cells are often not visually distinguishable from peritumoral brain during surgery. To address this, we conducted a multicenter study testing whether the Sentry System could distinguish the three most common types of brain tumors from brain tissue in a label-free manner. The Sentry System is a new real time, in situ brain tumor detection device that merges Raman spectroscopy with machine learning tissue classifiers. Nine hundred and seventy-six in situ spectroscopy measurements and colocalized tissue specimens were acquired from 67 patients undergoing surgery for glioblastoma, brain metastases, or meningioma to assess tumor classification. The device achieved diagnostic accuracies of 91% for glioblastoma, 97% for brain metastases, and 96% for meningiomas. These data show that the Sentry System discriminated tumor containing tissue from non-tumoral brain in real time and prior to resection.

OS07.3.A Phase 1/2 clinical trial of blood-brain barrier opening with the SonoCloud-9 implantable ultrasound device in recurrent glioblastoma patients receiving IV carboplatin

Abstract Background Low intensity pulsed ultrasound (LIPU) in combination with microbubbles is a promising approach for brain drug delivery. A phase 1/2 clinical study (NCT03744026) was initiated to demonstrate the safety and efficacy of blood-brain barrier (BBB) disruption over a large volume using an implantable ultrasound system (SonoCloud-9) in patients with recurrent glioblastoma receiving carboplatin chemotherapy. Material and Methods The SonoCloud-9 device (Carthera, Paris, France) was placed at the end of tumor resection and replaced the bone flap. The device was activated 9-14 days after surgery for a duration of 270 seconds every 4 weeks until progression or treatment completion, concomitantly with IV DEFINITY microbubbles (10 μl/kg, Lantheus, Billerica, US). The Phase 1 cohort consisted of an escalation of BBB disruption volume by activation of 3 (n=3), 6 (n=3), then 9 (n=3) emitters of the device. Dose limiting toxicity (DLT) was assessed during the first 2 weeks after the 1st sonication. A subsequent expansion cohort consisted of patients treated with 9 emitters in which the primary endpoint was assessment of BBB opening on MRI using gadolinium (<1 hr after sonication). All patients received carboplatin either after (n=21) or before (n=12) device activation to disrupt the BBB. In addition, a sub-study was performed to investigate carboplatin concentration enhancement in the peritumoral region with sonication at time of device implantation. Results Study accrual is complete with 38 patients enrolled and 33 patients having been implanted and received at least one sonication+carboplatin. A total of 101 sonications were performed (range=1-10 sonication sessions/patient). No DLTs were observed. A total of 14 SAEs were observed including five events considered as possibly treatment related. BBB disruption was confirmed by gadolinium enhancement after sonication. In an analysis of 60 treatments in 27 patients that had all nine emitters active, 90% of activated emitters led to BBB opening in gray and/or white matter with good repeatability of BBB opening. In 3 patients who underwent intraoperative sonication and carboplatin administration, a 7.58-fold increase in brain/plasma drug levels was demonstrated. Updated and mature outcome results will be presented. Conclusion These results confirm the safety and feasibility of repeated BBB disruption using an implantable ultrasound system. LIPU substantially increases drug levels in the peritumoral brain.

Abstract 1569: pSTAT3+ stromal cells drive the invasive growth of brain metastases

Abstract Background: Brain metastases (BrM) with highly invasive (HI) growth patterns are associated with shortened local recurrence free- and overall survival compared to minimally invasive (MI) lesions (Dankner et al. 2021). Compared to MI lesions, HI BrM form abundant contacts with cells in the peritumoral brain, particularly GFAP+ reactive astrocytes (RAs). RAs expressing phosphorylated STAT3 (pSTAT3+ GFAP+ cells) have been shown to be required for BrM colonization and outgrowth (Priego et al. 2018). Here, we investigate the role of pSTAT3+ cells in the brain microenvironment in promoting invasive growth. Methods: We performed immunohistochemistry to identify pSTAT3+ GFAP+ cells in HI and MI human and patient-derived xenograft BrM. We assessed how pharmacological inhibition or genetic ablation of STAT3 affected HI and MI BrM growth in vivo with patient-derived xenograft and syngeneic models of BrM. The secretome of STAT3+ RAs was interrogated to identify STAT3 target genes that could drive invasive cancer growth. scRNA-Seq from patients with highly invasive brain metastases was used to examine the expression of candidate invasion factors in distinct cell types within the brain. Finally, cancer cell invasion was modeled in vitro using a brain slice-tumor co-culture assay. Results: HI BrM displayed increased pSTAT3+GFAP+ cells compared to MI lesions. Pharmacological STAT3i with Legasil (Silibinin) or genetic ablation of STAT3 specifically in RAs decreased in vivo growth of HI, but not MI, BrM. Brain slice cultures treated with STAT3-activating cytokines induced cancer cell invasion, a response that was ablated with STAT3i. Chi3L1 was identified as a STAT3 target gene expressed abundantly by stromal cells in the BrM microenvironment. Cancer cells treated with recombinant Chi3L1 showed enhanced invasion into brain slice cultures compared to control-treated cells. Conclusions: pSTAT3+GFAP+ cells are over-represented in HI BrM, rendering HI BrM preferentially sensitive to STAT3i. pSTAT3+ stromal cells functionally contribute to BrM invasion within the brain, in part through Chi3L1. This work nominates HI histopathological growth pattern as a predictive biomarker of response to STAT3i, and highlights Chi3L1 as a novel therapeutic target for the management of HI BrM. Citation Format: Matthew Dankner, Sarah M. Maritan, Neibla Priego, Javad Nadaf, Andy Nkili, Rebecca Zhuang, Georgia Kruck, Dongmei Zuo, Alexander Nowakowski, Yanis Inglebert, Paul Savage, Morag Park, Marie-Christine Guiot, Anne McKinney, William J. Muller, Manuel Valiente, Kevin Petrecca, Peter M. Siegel. pSTAT3+ stromal cells drive the invasive growth of brain metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1569.

The epileptic landscape of IDH mutant gliomas.

2064 Background: Tumor-associated epilepsy (TAE) is a frequent complication of diffusely infiltrative gliomas. TAE not only impairs quality-of-life, but it can even be life-threatening. Furthermore, glioma cells have been shown to proliferate and migrate faster when exposed to firing neurons. We previously showed that isocitrate dehydrogenase 1 mutant (IDHmut) gliomas were more likely to cause preoperative seizures than IDH wildtype (IDHwt) gliomas, and that the chemical product of IDHmut, D2HG, increased synchronized network bursts in cultured neurons (PMID: 28404805). But the mechanism whereby this occurs, whether IDHmut inhibitors can block this, and whether seizure risk also varies by IDHmut status postoperatively, are unknown. Methods: Methods are embedded in Results. Results: We discovered that exogenous 3 mM D2HG had a 150% greater effect on the firing rate of cultured mouse cortical neurons when nonneoplastic glia cells were present versus when they were absent ( P=0.002). Although a recently published study suggested that D2HG causes seizures through mTOR activation (PMID: 34994387), we found that D2HG reduced neuronal mTOR activity in neuronal-glial cocultures by 54% ( P=0.0004). Patch clamp analyses showed that, while D2HG does not directly activate glutamate receptors, it does act as a glutamate transport substrate, thus potentially interfering with the ability of glial cells to take up glutamate released into the synaptic cleft. Coculture with patient-derived IDHmut glioma cells increased the firing rate of human cortical neuron/astrocyte spheroids by up to 272%, and an IDHmut inhibitor currently being tested in clinical trials, AG881, reduced the excitatory effect of IDHmut glioma cells on spheroids by 79% ( P=0.0008). Using a novel in vivo model of TAE, wherein EEG recordings were taken of immunocompetent mice engrafted with an isogenic pair of Sleeping Beauty transposase-engineered mouse glioma lines (NRAS/ATRX/TP53mut ± IDHmut), we found that IDHmut gliomas produced 7.6-fold more epileptiform spikes than IDHwt gliomas ( P=0.004). RNA-Seq analysis of the peritumoral mouse brain tissue showed that this increase in spikes was associated with significantly increased expression of key genes known to be upregulated in epilepsy, including SLC12A5, THSB1, VEGFA, FOSL2, and SYNPO. Treatment with 5 mg/kg AG881 by daily oral gavage reduced those spikes in IDHmut-engrafted mice by 51% within three days ( P=0.027), whereas vehicle control had no effect ( P=0.33). Among 247 patients with grade 2–4 adult-type diffuse gliomas, multivariable time-to-event analysis showed that postoperative seizure risk increased with preoperative seizures, subtotal resection, and IDHmut astrocytoma. Conclusions: Together, these data show that (i) the D2HG product of IDHmut gliomas increases neuronal excitation in a glial-dependent manner; (ii) IDHmut also affects postoperative seizure risk; (iii) IDHmut inhibitors may improve TAE control.

BSCI-10. Invasive growth of brain metastases is driven by cancer cell-pSTAT3+ reactive astrocyte crosstalk

BackgroundBrain metastases (BrM) with a highly invasive (HI) histological growth pattern are associated with poor prognosis compared to minimally invasive (MI) masses. Compared to MI lesions, HI BrM form greater contacts with cells in the peritumoral brain, particularly reactive astrocytes (RAs). RAs expressing phosphorylated STAT3 (pSTAT3+RAs) have been shown to promote BrM colonization. Here, we investigate the role of pSTAT3+RAs in promoting invasive growth of HI BrM.MethodsWe performed immunohistochemistry to identify pSTAT3+RAs in HI and MI human and patient-derived xenograft BrM. We assessed how pharmacological STAT3 inhibition or RA-specific STAT3 genetic ablation affected HI and MI BrM growth in vivo. scRNA-seq data generated from HI BrM astrocytes were integrated with published RA secretome data to identify STAT3 targets expressed by RAs that may drive invasion. Cancer cell invasion was modeled in vitro using a brain slice-tumor co-culture assay.ResultsHI BrM display increased pSTAT3-positivity within RAs when compared to MI lesions. Pharmacological STAT3 inhibition with Legasil (Silibinin) or genetic ablation decreased in vivo growth of HI, but not MI, BrM. Brain slice cultures treated with STAT3-activating cytokines induced cancer cell invasion, a response that was ablated following STAT3 inhibition. Chi3L1 was identified as a STAT3 target expressed by RAs. Cancer cells treated with recombinant Chi3L1 showed greater invasion into brain slice cultures compared to untreated cells.ConclusionspSTAT3+RAs are over-represented in HI BrM, rendering HI BrM preferentially sensitive to STAT3 inhibition. pSTAT3+RAs functionally contribute to BrM invasion within the brain, in part through Chi3L1-mediated activity. This work identifies STAT3 and Chi3L1 as clinically relevant therapeutic targets in management of HI BrM.

CSIG-41. UPREGULATED EXPRESSION OF THE ARYL HYDROCARBON RECEPTOR PATHWAY IN BRAIN METASTASES FROM MALIGNANT MELANOMA

The Aryl-hydrocarbon-receptor (AHR) is a ligand activated transcription factor linked to exogenic carcinogenic agents such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In 2011, the tryptophan (TRP) catabolite kynurenine (KYN) was identified as an endogenous ligand for AHR. The AHR is involved in several crucial processes such as cell migration, tumorigenesis, and immune function. Dysregulation of AHR, its nuclear translocator (ARNT), its repressor AHRR and the KYN building Enzyme TRP-2,3-dioxygenase 2 (TDO) has been linked to poor survival in patients with Glioblastoma. We aimed to evaluate the AHR-pathway in brain metastases. Using qRT-PCR, gene expression was analyzed in 19 brain-metastases of melanoma patients, 10 control tissues from peritumoral brain and 10 glioblastoma (GBM) samples. Differences in the expression of AHR, ARNT, AHRR, TDO as well as the AHR/AHRR ratio between tumor tissue and control were analyzed. Results are depicted in mean values with standard deviation (SD) and in Arbitrary Units (AU). p<.05 was considered significant. Both, AHR and ARNT were massively overexpressed in metastatic tissues (p<.01) (6- and 4.5-fold) in comparison to control (AHR: 3.64 ± 2.32 vs. .58 ±.50; p<0.01 and ARNT: 3.81 ± 2.25 vs. .83 ±.48, p<.01). AHRR and TDO where not significantly upregulated (.73 ±.88 vs. .41 ±.35; p=.31 and .37 ±.61 vs. .14 ±.09; p=.46). The ratio of AHR and its repressor AHRR (AHRR/AHR) was significantly different between metastases and control, hinting at a distinct regulatory imbalance (.55 ± 1.09 vs. .18 ± 1.60 p<.01). The difference of AHR expression in metastases and GBM did not quite reach significance (3.64 ± 2.32 vs. 1.27 ± 1.89; p=.055). ARNT was significantly elevated in metastases compared to GBM (3.81 ± 2.25 vs. 1.7 ±.1.15, p<.01). The AHR pathway is significantly upregulated in melanoma brain metastases and might play a pathophysiological role in growth and progression of brain metastases.

P01.19 Activation of the mTOR signaling pathway in peritumoral tissues can cause glioma-associated seizures

AbstractEpileptic seizures, the most common symptom accompanying glioma, are closely associated with tumor growth and patient quality of life. However, the association between glioma and glioma-related epilepsy is poorly understood. In fact, findings related to the location of epileptogenicity have been inconsistent in previous studies. We investigated seizure foci in patients with glioma and the corresponding association between glioma-related epilepsy and the tumoral and peritumoral microenvironment. Clinical characteristics, extracellular electrophysiology, immunohistochemistry, and western blots were conducted on 12 patients with glioma; nine patients had histories of preoperative seizures while three did not. Samples from included patients were used to identify seizure foci and mTOR pathway status. Electrophysiological recordings were conducted on 36 samples (tumor, peritumoral, and normal brain tissues) from 12 patients. Interictal-like discharges (ILDs) were observed in seven of nine peritumoral tissues obtained from patients with glioma that had experienced perioperative seizures. No ILDs were observed in any other sample groups. Western blots and immunohistochemistry for mTOR pathway proteins (mTOR and S6k) suggested that the mTOR pathway was activated in peritumoral tissues of patients with seizure history, but inactivated in patients without seizure history. Our results suggest that mTOR pathway expression in peritumoral tissues is associated with tumor-related seizures, thus providing a potential target for therapeutics aimed at simultaneously controlling gliomas and seizures.

TMIC-03. IMAGING BRAIN TUMOR-ASSOCIATED NEUROINFLAMMATION IN ANIMAL MODELS USING FERUMOXYTOL

In the brain tumor microenvironment, non-neoplastic cells with inflammatory function such as tumor-associated macrophages can influence the survival, proliferation and infiltrative activity of cancer cells. The ultrasmall superparamagnetic iron oxide nanoparticle, ferumoxytol, can be used as a contrast agent for magnetic resonance imaging (MRI) of brain vasculature, intracerebral tumors and neurological lesions. Although ferumoxytol is a blood pool agent immediately after infusion, we have shown that by 24h ferumoxytol leaks across the damaged blood-brain barrier in a rat model of acute neuroinflammation, where MRI signal changes correlated with nanoparticle uptake by macrophages, microglia and activated astrocytes. The purpose of this study was to test the hypothesis that delayed MRI would demonstrate uptake of ferumoxytol by inflammatory cells in and around the tumor in rat models of intracerebral metastasis. Immune-compromised nude rats received intracerebral implantation of human metastatic cancer cells including H460 non-small cell lung carcinoma and HCC1954 breast carcinoma. When brain tumors were >10mm3 volume, rats underwent baseline T1, T2, and T2* scans on the 11.75T Bruker MRI scanner, then received ferumoxytol 25 mg/kg IV. MRI scans were repeated 24h after ferumoxytol, and rat brains were immediately harvested for immunohistochemical analysis. Post-ferumoxytol T1-weighted scans showed pockets of hypointensity dispersed throughout the tumor and, occasionally, a distinct rim of signal dropout at the tumor border, combined with hyperintensity extending 1-2 mm around the tumor mass. Post-ferumoxytol T2-weighted scans showed mottled signal dropout throughout the tumor, while T2* scans showed intense hypointensity throughout the tumor mass extending into surrounding brain. Immunohistochemistry for the ferumoxytol coating showed intense staining in macrophages within necrotic areas of the tumor and dispersed staining in cells of astroglial morphology in peritumoral brain, but little to no staining within tumor cells. We conclude that delayed ferumoxytol MRI provides a biomarker of the inflammatory component of intracerebral tumors.

Expression pattern of invasion-related molecules in the peritumoral brain

ObjectiveThe effectiveness of therapy of intracerebral neoplasms is mainly influenced by the invasive behaviour of the tumour. The peritumoral invasion depends on the interaction between the tumour cells and the extracellular matrix (ECM) of the surrounding brain. The invading tumour cells induce change in the activity of proteases, synthases and expression of ECM-components. These alterations in the peritumoral ECM are in connection to the highly different invasiveness of gliomas and metastatic brain tumours. To understand the fairly modified invasive potential of anaplastic intracerebral tumours of different origin, the effect of tumour on the peritumoral ECM and alterations of invasion related ECM components in the peritumoral brain were evaluated. MethodsFor this reason the mRNA expression of 19 invasion-related molecules by quantitative reverse transcriptase polymerase chain reaction was determined in normal brain tissue (Norm), in the peritumoral brain tissue of glioblastoma (peri-GBM) and of intracerebral adenocarcinoma metastasis (peri-Met). To evaluate the translational expression of the investigated molecules protein levels were determined by targeted proteomic methods. ResultsEstablishing the invasion pattern of the investigated tissue samples 8 molecules showed concordant difference at mRNA and protein levels in the peri-GBM and peri-Met, 11 molecules in the peri-Met and normal brain and 12 in the peri-GBM and normal brain comparison. ConclusionOur results bring some ECM molecules into focus that probably play key role in arresting tumour cell invasion around the metastatic tumour, and also in the lack of impeding tumour cell migration in case of glioblastoma.

Role of neurochemical navigation with 5-aminolevulinic acid during intraoperative MRI-guided resection of intracranial malignant gliomas

ObjectiveTo evaluate the role of the neurochemical navigation with 5-aminolevulinic acid (5-ALA) during intraoperative MRI (iMRI)-guided resection of the intracranial malignant gliomas. MethodsThe analysis included 99 consecutive surgical cases. Resection of the bulk of the neoplasm was mainly guided by the updated neuronavigation based on the low-field-strength (0.3T) iMRI, whereas at the periphery of the lesion neurochemical navigation with 5-ALA was additionally used. ResultsIn total, 286 tissue specimens were obtained during surgeries for histopathological examination. According to iMRI 98 samples with strong (91 cases), weak (6 cases), or absent (1 case) fluorescence corresponded to the bulk of the lesion and all of those ones contained tumor. Out of 188 tissue specimens obtained from the “peritumoral brain,” the neoplastic elements were identified in 89%, 81% and 29% of samples with, respectively, strong (107 cases), weak (47 cases) and absent (34 cases) fluorescence. Positive predictive values of the tissue fluorescence for presence of neoplasm within and outside of its boundaries on iMRI were 100% and 86%, respectively. ConclusionNeurochemical navigation with 5-ALA is useful adjunct during iMRI-guided resection of intracranial malignant gliomas, which allows identification of the tumor extension beyond its radiological borders.

Cerebral hypoperfusion-assisted intra-arterial deposition of liposomes in normal and glioma-bearing rats.

Optimizing liposomal vehicles for targeted delivery to the brain has important implications for the treatment of brain tumors. The promise of efficient, brain-specific delivery of chemotherapeutic compounds via liposomal vehicles has yet to be achieved in clinical practice. Intra-arterial injection of specially designed liposomes may facilitate efficient delivery to the brain and to gliomas. To test the hypothesis that cationic liposomes may be effectively delivered to both normal and glioma-bearing brain tissue utilizing a strategy of intra-arterial injection during transient cerebral hypoperfusion. Cationic, anionic, and neutral liposomes were separately injected via the internal carotid artery of healthy rats during transient cerebral hypoperfusion. Rats bearing C6 gliomas were similarly injected with cationic liposomes. Liposomes were loaded with DilC18(5) dye whose concentrations can be measured by light absorbance and fluorescence methods. After intra-arterial injection, a robust uptake of cationic in comparison with anionic and neutral liposomes into brain parenchyma was observed by diffuse reflectance spectroscopy. Postmortem multispectral fluorescence imaging revealed that liposomal cationic charge was associated with more efficient delivery to the brain. Cationic liposomes were also readily observed within glioma tissue after intra-arterial injection. However, over time, cationic liposomes were retained longer and at higher concentrations in the surrounding, peritumoral brain than in the tumor core. This study demonstrates the feasibility of cationic liposome delivery to brain and glioma tissue after intra-arterial injection. Highly cationic liposomes directly delivered to the brain via an intracarotid route may represent an effective method for delivering antiglioma agents.

Diffusion-weighted MRI characteristics of the cerebral metastasis to brain boundary predicts patient outcomes.

BackgroundDiffusion-weighted MRI (DWI) has been used in neurosurgical practice mainly to distinguish cerebral metastases from abscess and glioma. There is evidence from other solid organ cancers and metastases that DWI may be used as a biomarker of prognosis and treatment response. We therefore investigated DWI characteristics of cerebral metastases and their peritumoral region recorded pre-operatively and related these to patient outcomes.MethodsRetrospective analysis of 76 cases operated upon at a single institution with DWI performed pre-operatively at 1.5T. Maps of apparent diffusion coefficient (ADC) were generated using standard protocols. Readings were taken from the tumor, peritumoral region and across the brain-tumor interface. Patient outcomes were overall survival and time to local recurrence.ResultsA minimum ADC greater than 919.4 × 10-6 mm2/s within a metastasis predicted longer overall survival regardless of adjuvant therapies. This was not simply due to differences between the types of primary cancer because the effect was observed even in a subgroup of 36 patients with the same primary, non-small cell lung cancer. The change in diffusion across the tumor border and into peritumoral brain was measured by the “ADC transition coefficient” or ATC and this was more strongly predictive than ADC readings alone. Metastases with a sharp change in diffusion across their border (ATC >0.279) showed shorter overall survival compared to those with a more diffuse edge. The ATC was the only imaging measurement which independently predicted overall survival in multivariate analysis (hazard ratio 0.54, 95% CI 0.3 – 0.97, p = 0.04).ConclusionsDWI demonstrates changes in the tumor, across the tumor edge and in the peritumoral region which may not be visible on conventional MRI and this may be useful in predicting patient outcomes for operated cerebral metastases.

Metabolic alterations in the peritumoral brain in cases of meningiomas: 1H-MRS study

The objective of the present study was metabolic characterization of the peritumoral brain in the vicinity of meningiomas using proton magnetic resonance spectroscopy (1H-MRS). Data of long-echo (TR: 2000 ms, TE: 136 ms) single-voxel spectroscopic investigations were obtained during preoperative examination of 81 patients (19 men and 62 women; mean age, 56.5 years). Twenty-seven neoplasms were disclosed incidentally. Moderate-to-severe peritumoral edema was presented in 20 cases. Invasive growth of the tumor was macroscopically identified during surgery in 35 cases. Analyzed metabolites included N-acetylaspartate (NAA), choline-containing compounds (Cho), mobile lipids (Lip) and lactate (Lac). Compared to distant normal-appearing white matter 1H-MRS of the brain in the vicinity of meningiomas disclosed statistically significant decrease of NAA content (P=0.0019). Investigated metabolic parameters depended on the presence of invasive tumor growth and prominent peritumoral edema, as well as on the size of the neoplasm, its location, and the patient's age. More severe 1H-MRS-detected peritumoral metabolic abnormalities associated with invasive growth of meningioma might be used for its prediction. The presence of meningioma-related neurological symptoms was mainly determined by the size of the tumor, while might be also associated with lower normalized NAA/Cho ratio and more frequent presence of a Lip peak in the peritumoral brain. In conclusion, decrease of NAA content constitutes the most prominent 1H-MRS-detected brain abnormality in the vicinity of intracranial meningiomas. Peritumoral spectroscopic alterations are determined by a variety of factors, can be predictive for invasive tumor growth and may correspond to presented neurological symptoms.

Performance of sulfhydryl boron hydride in patients with grade III and IV astrocytoma: a basis for boron neutron capture therapy.

This study investigated the rationale of boron neutron capture therapy (BNCT) for the treatment of Grade III and IV astrocytoma. The European Community joint research program on BNCT plans to use sulfhydryl boron hydride (BSH) in clinical trials. The work presented here, examines the performance of BSH in eight patients with Grade III and IV astrocytoma using a measurement technique which precisely correlates the boron uptake with the histology of the tumor and the peritumoral brain. Astrocytomas are exceptionally heterogeneous and spread migrating tumor cells into the surrounding brain. The patients were infused with 50 mg BSH per kilogram of body weight at 12, 18, 24 or 48 hours before surgery. At the time of operation, specimens were obtained of the tumor, skin, muscle, dura, blood, urine, and, when surgically possible, the brain adjacent to tumor. In three patients the intracellular boron distribution was investigated by subcellular fractionation. The blood clearance was biphasic with half-lives of 0.6 and 8.2 hours. After 3 days, approximately 70% of the dose injected was excreted in the urine. The maximum boron concentration in the tumor was 20 ppm, 12 hours after the infusion. The tumor-to-blood ratios ranged between 0.2 and 1.4, with the highest values after 18 to 24 hours. In the brain specimens the boron concentration never exceeded 1 ppm. This work confirms a selective uptake of boron in the tumor compared to the surrounding brain and that boron, to some extent, is incorporated in the tumor cells.

Expression of tumour necrosis factor-α, -β and interferon-γ genes within human neuroglial tumour cells and brain specimens

Expression of cytokine genes, TNF-α, TNF-β and IFN-γ, in human astroglial cell lines and in fresh brain specimens was studied by PCR. mRNA transcripts of TNF-α could be detected in three out of five astrocytomas and neuroblastoma cell lines, and after stimulation with IL-1β/IFN-γ or LPS/IFN-γ all these cell lines expressed TNF-α genes. TNF-β genes could not be detected in these cell lines. We were able to detect expression of IFN-γ genes within two astrocytoma cell lines, which interestingly did not show TNF-α activity. In addition to the cultured cells, we also examined gene expression of these cytokines within four human malignant astrocytoma specimens, two peritumoral brain and two autopsied normal brains. The results show that tumour and surrounding reactive lesions express TNF-α genes (four of six) but not normal brains. The concentration of these cytokines in the supernatant of cultured cells was measured quantitatively by TNF-α, -β or IFN-γ ELISA. The combined stimulation of these neuroglial cell lines with IL-1β and LPS or IFN-γ, revealed a high level of TNF-α activity. This was especially evident with a neuroblastoma cell line. The concentration of TNF-α in the supernatant of the IMR32 neuroblastoma cell line increased markedly upon stimulation with IL-1β in both a time- and dose-dependent fashion in the presence of LPS or IFN-γ. Next, we examined expression of IL-1β and IFN-γ genes in the brain specimens. The result shows that four in six tumour and peritumoral regions expressed IFN-γ genes and one specimen showed IL-β gene by PCR. From these experiments it is suspected that neuroglial cell-derived TNF-α induced by IL-1β of IFN-γ may participate in local immune reactions of the brain in an autocrine and paracrine fashion.

Proton nuclear magnetic resonance studies on water structure in peritumoral edematous brain tissue.

Spin-lattice relaxation times (T1) of water protons and cross-relaxation times (TIS) between irradiated protein and water protons were measured to study the water structure in peritumoral edematous brain tissue of rats. Despite small changes in T1, water, and electrolyte contents, TIS values of water protons were significantly reduced in peritumoral edematous brain tissue when compared to those of the controls. Results indicate that the water structure in brain tissues may become altered at an early stage of edemic formation without causing any significant changes in cellular hydration. TIS might serve as a sensitive parameter for studying the water structure in a variety of tissues, such as in edematous brain tissue.

Expression of granulocyte colony stimulating factor and granulocyte-macrophage colony stimulating factor genes in human astrocytoma cell lines and in glioma specimens

Expression of granulocyte (G) and granulocyte-macrophage (GM) colony stimulation factor (CSF) genes in human cells of astroglial lineage was studied. Primers for CSFs were used to analyze RNA transcripts in 5 cultured human astrocytoma cell lines and 8 fresh brain specimens by polymerase chain reaction. Constitutive expression of mRNA transcripts of GM-CSF could be detected in all astrocytoma and one neuroblastoma cell lines, and two out of 5 unstimulated astrocytomas, U87MG and U138 MG, expressed G-CSF genes. After stimulation with interleukin (IL)-1β + tumor necrosis factor (TNF)-α, all cell lines expressed G-CSF. In addition to the cultured cells, we examined gene expression within human malignant astrocytoma, peritumoral brain and autopsied normal brains. The results show that some of the tumor and its surrounding reactive lesions express G- and GM-CSF genes but normal brains do not. The concentration of G- and GM-CSF in supernatants of cultured cells was assessed at the protein level by ELISA. A low level of GM-CSF activity was constitutively present in all astrocytomas. G-CSF was detected in unstimulated U87MG and U138MG and other cell lines could synthesize G-CSF after the stimulation of IL-1β and TNF-α at the level of mRNA. Furthermore, the concentration of CSFs increased markedly upon stimulation with IL-1β and/or TNF-α in both a time- and dose-dependent fashion. From these results, it is suspected that astroglial cell-derived CSFs may participate in local immune reactions accompanying infection, degeneration and malignancies in the brain.

Neoplastic and reactive human astrocytes express interleukin-8 gene

Expression of lymphokine genes in the human astroglial cell lineage was studied. Primers for 9 different human lymphokines, from IL-1 alpha to IL-8, were used to analyze RNA transcripts in 5 cultured human astrocytoma cell lines and fresh brain specimens by PCR. mRNA transcripts for IL-8 were detected in all neuroglial cells. In addition to the cultured cells, we examined IL-8 gene expression within human malignant astrocytoma, peritumoral brain and autopsied normal brains. The result shows that tumor and cells of the surrounding reactive lesion express IL-8 genes, but it is not expressed in normal brains. Next, the concentration of IL-8 in supernatants of cultured cells was measured quantitatively by a solid phase ELISA assay. IL-8 activity was produced constitutively in all astrocytomas and increased markedly upon stimulation with IL-1 beta or TNF alpha, in both a time- and dose-dependent fashion. From these results, it is suspected that astroglial cell-derived IL-8 may take part in neutrophil-mediated inflammation which accompanies infection, degeneration and malignancy in the brain.