Mesenchymal stem cells as therapeutic vehicles for glioma

Glioma is a disease with a poor prognosis despite the availability of multimodality treatments, and the development of novel therapies is urgently needed. Challenges in glioma treatment include the difficulty for drugs to cross the blood-brain barrier when administered systemically and poor drug diffusion when administered locally. Mesenchymal stem cells exhibit advantages for glioma therapy because of their ability to pass through the blood-brain barrier and migrate to tumor cells and their tolerance to the immune system. Therefore, mesenchymal stem cells have been explored as vehicles for various therapeutic agents for glioma treatment. Mesenchymal stem cells loaded with chemotherapeutic drugs show improved penetration and tumor accumulation. For gene therapy, mesenchymal stem cells can be used as vehicles for suicide genes, the so-called gene-directed enzyme prodrug therapy. Mesenchymal stem cell-based oncolytic viral therapies have been attempted in recent years to enhance the efficacy of infection against the tumor, viral replication, and distribution of viral particles. Many uncertainties remain regarding the function and behavior of mesenchymal stem cells in gliomas. However, strategies to increase mesenchymal stem cell migration to gliomas may improve the delivery of therapeutic agents and enhance their anti-tumor effects, representing promising potential for patient treatment.

Midline invasion predicts poor prognosis in diffuse hemispheric glioma, H3 G34-mutant: an individual participant data review

INTRODUCTION

Diffuse hemispheric glioma, H3 G34-mutant (DHGs), is a newly categorized tumor in pediatric-type diffuse high-grade gliomas, World Health Organization grade 4, with a poor prognosis. Although prognostic factors associated with genetic abnormalities have been reported, few reports have examined the clinical presentation of DHGs, especially from the viewpoint of imaging findings. In this study, we investigated the relationship between clinical factors, including imaging findings, and prognosis in patients with DHGs.

METHODS

We searched Medline through the PubMed database using two search terms: "G34" and "glioma", between 1 April 2012 and 1 July 2023. We retrieved articles that described imaging findings and overall survival (OS), and added one DHG case from our institution. We defined midline invasion (MI) as invasion to the contralateral cerebrum, brainstem, corpus callosum, thalamus, and basal ganglia on magnetic resonance imaging. The primary outcome was 12-month survival, estimated using Kaplan-Meier curves and logistic regression.

RESULTS

A total of 96 patients were included in this study. The median age was 22 years, and the proportion of male patients was 48.4%. Lesions were most frequently located in the frontal lobe (52.6%). MI was positive in 39.6% of all patients. The median OS was 14.4 months. Univariate logistic regression analysis revealed that OS was significantly worse in the MI-positive group compared with the MI-negative group. Multivariate logistic regression analysis revealed that MI was an independent prognostic factor in DHGs.

CONCLUSIONS

In this study, MI-positive cases had a worse prognosis compared with MI-negative cases.

PREVIOUS PRESENTATIONS

No portion of this study has been presented or published previously.

[Innovations in Combined Surgery of Endoscopic Transsphenoidal Surgery and Craniotomy]

Combined endoscopic transsphenoidal surgery and craniotomy may be useful for tumors extending into the suprasellar region or ventricles and for tumors extending simultaneously into the nasal sinuses and intracranial space. This method allows two surgeons to share the surgical field while compensating for each other's blind spots and allows for safe tumor removal by separating the normal structure from the tumor and protecting the normal structure. Simultaneous combined endoscopic transsphenoidal surgery and craniotomy require a lot of equipment; however, by devising the layout of the equipment in the operating room, the staff involved in the surgery can perform their roles more effectively. However, this method results in extensive dural and cranial defects, and prevention of cerebrospinal fluid leakage and perioperative surgical site infection is essential. Skull base reconstruction using autologous tissues and medical materials at appropriate locations can reduce the risk of postoperative cerebrospinal fluid leakage and surgical site infection. Furthermore, multilayered reconstruction using restorative medical materials eliminates the need for autologous tissue, is minimally invasive, shortens the operative time, reduces postoperative stress, and shortens the length of hospital stay. A combination of endoscopic transsphenoidal surgery and craniotomy will contribute to the improvement of the safety of highly difficult tumorectomies under a reliable skull base reconstruction method.

Multidrug chemotherapy, whole-brain radiation and cytarabine therapy for primary central nervous system lymphoma in elderly patients with dose modification based on geriatric assessment: study protocol for a phase II, multicentre, non-randomised study

INTRODUCTION

Multidrug chemoimmunotherapy with rituximab, high-dose methotrexate, procarbazine and vincristine (R-MPV) is a standard therapy for younger patients with primary central nervous system lymphoma (PCNSL); however, prospective data regarding its use in elderly patients are lacking. This multi-institutional, non-randomised, phase II trial will assess the efficacy and safety of R-MPV and high-dose cytarabine (HD-AraC) for geriatric patients with newly diagnosed PCNSL.

METHODS AND ANALYSIS

Forty-five elderly patients will be included. If R-MPV does not achieve complete response, the patients will undergo reduced-dose, whole-brain radiotherapy comprising 23.4 Gy/13 fractions, followed by local boost radiotherapy comprising 21.6 Gy/12 fractions. After achieving complete response using R-MPV with or without radiotherapy, the patients will undergo two courses of HD-AraC. All patients will undergo baseline geriatric 8 (G8) assessment before HD-AraC and after three, five and seven R-MPV courses. Patients with screening scores of ≥14 points that decrease to <14 points during subsequent treatment, or those with screening scores <14 points that decrease from the baseline during subsequent treatment are considered unfit for R-MPV/HD-AraC. The primary endpoint is overall survival, and the secondary endpoints are progression-free survival, treatment failure-free survival and frequency of adverse events. The results will guide a later phase III trial and provide information about the utility of a geriatric assessment for defining chemotherapy ineligibility.

ETHICS AND DISSEMINATION

This study complies with the latest Declaration of Helsinki. Written informed consent will be obtained. All participants can quit the study without penalty or impact on treatment. The protocol for the study, statistical analysis plan and informed consent form have been approved by the Certified Review Board at Hiroshima University (CRB6180006) (approval number: CRB2018-0011). The study is ongoing within nine tertiary and two secondary hospitals in Japan. The findings of this trial will be disseminated through national and international presentations and peer-reviewed publications.

TRIAL REGISTRATION

jRCTs061180093.

CBMS-5 STEAROYL-COA DESATURASE INHIBITOR INDUCES APOPTOSIS VIA ENHANCING LIPOLYSIS IN IDH MUTANT GLIOMA

Background

Little is known about the antineoplastic effect and the mechanism of Stearoyl-CoA desaturase (SCD) inhibitor which catalyzes the biosynthesis of monounsaturated fatty acids (MUFA). Mutant isocitrate dehydrogenase (IDH) catalyzes the NADPH-mediated reduction of α-ketoglutarate (αKG) to 2-hydroxyglutarate (2HG) and causes metabolic reprograming of lipid. In this study, to develop a feasible drug for IDH mutant glioma, we have investigated the changes of the lipid distribution and the mechanism of antineoplastic effect of SCD inhibition in IDH mutant glioma.

Materials and Methods

We prepared genetically engineered glioma cell lines (U251 wild type: U251WT and U251 IDH mutant: U251mut) and patient derived cell lines (TS603 and GSC923). Lipid metabolic analysis was conducted by using Raman imaging spectroscopy and LC-MS, and functional analysis for the role of SCD expression in IDH mutant glioma was investigated by RNA sequence and Western-blotting. Results: In LC-MS analysis of the extracted Endoplasmic Reticulum, MUFAs were distributed significantly higher in IDH mutant than wild type. SCD expression was increased in IDH mutant compared to wild type due to 2HG-mediated upregulation of SCD. Therefore, IDH mutant in which SCD expression level was high indicated high sensitivity to SCD inhibitor, and apoptosis was highly induced in IDH mutant compared to wild type. RNA sequencing was performed in U251mut treated with SCD inhibitor compared to U251mut treated with DMSO, and lipid droplet metabolism-associated RNA expression was significantly changed in U251mut treated with SCD inhibitor. We checked lipid droplet in U251mut with presence or absence of SCD inhibitor, and lipolysis was induced by SCD inhibitor treatment, suggesting that SCD inhibition is associated with the apoptosis in IDH mutant via enhanced lipolysis mechanism.

Conclusions

2HG produced in IDH mutant glioma directly induces SCD expression and enhances sensitivity to SCD inhibitor, which suggests that SCD inhibitor is an IDH mutant glioma-specific treatment strategy.

ET-5 POTENT BYSTANDER EFFECT IN SUICIDE GENE THERAPY USING TK-EXPRESSING STEM CELLS FROM HUMAN EXFOLIATED DECIDUOUS TEETH

Introduction

We investigated HSVTK/GCV suicide gene therapy for malignant glioma, and demonstrated the migration ability and antitumor effect of various tissue-derived pluripotent stem cells. In recent years, stem cells from human exfoliated deciduous teeth (SHED), which have excellent ethical and self-renewal ability, have attracted attention, especially in regenerative medicine. In this study, using SHEDTK transfected with TK, we examined the migration ability and antitumor effect against malignant glioma and metastasis models.

Methods

In vitro assay: Using Matrigel chamber, the migration ability of SHEDTK to conditioned medium (CM) of glioma cells, lung carcinoma cells, and various tumor growth factors (TGF) was examined. The antitumor effect was examined for cell viability by co-culturing SHEDTK and each tumor cell under the addition of GCV. in vivo assay: Using glioma model mice, SHEDTK migrating around the tumor was confirmed in brain sections. In addition, we co-implanted SHEDTK and administered GCV to glioma and metastasis model as therapeutic models, evaluated tumor reduction effect by bioluminescence, and confirmed survival curves.

Results

In vitro assay: SHEDTK significantly migrated to CM and TGF compared to control. The antitumor effect was observed even when the ratio of each tumor cell to SHEDTK was 128-256 times. in vivo assay: In glioma model mice, SHEDTK migrated around contralateral tumor. In the treatment experiment, the control group died of tumors, whereas the tumor in the treatment group disappeared within the period of GCV administration, and they survived without neurological deficits until 100 days later, and the overall survival time was improved with a statistically significant difference.

Conclusions

We confirmed the migration ability and antitumor effect of SHEDTK on malignant glioma and metastasis models. Suicide gene therapy using SHEDTK was suggested as novel gene therapy. In the future, we plan to conduct translational research such as preclinical studies and physician -initiated clinical trials.

Migration Capacity of Stem Cells from Human Exfoliated Deciduous Teeth Towards Glioma

BACKGROUND

Stem cells from human exfoliated deciduous teeth (SHED) are a mesenchymal stem cell type and have recently attracted attention for their high proliferative rate, multipotency, and immunosuppressive properties. However, SHED have not yet been investigated for anticancer properties. We therefore investigated whether SHED can be used as a treatment modality, particularly for anti-glioma therapy.

METHODS

In vitro, we examined the mobility of SHED and their ability to migrate towards glioma-conditioned medium and specific growth factors secreted by malignant gliomas. In vivo, we transplanted SHED into the left hemisphere of nude mice that had been previously implanted with human malignant glioma U87 cells into the right hemisphere. We assessed whether SHED had tumorigenic potential.

RESULTS

SHED exhibited strong migration ability towards malignant glioma in both in vitro and in vivo assays. In vitro, SHED migrated towards glioma-conditioned medium and specific growth factors such as stem cell factor, platelet-derived growth factor BB, C-X-C motif chemokine ligand 12, and vascular endothelial growth factor. SHED were accumulated around tumor cells in the contralateral hemisphere 1 week after transplantation. Moreover, SHED remained in the brains of nude mice 150 days after transplantation. Finally, we verified that SHED had no malignant transformation or engraftment of SHED in the mouse brain.

CONCLUSIONS

Our findings indicate that SHED can potentially be applied to track malignant glioma.

TMET-03. STEAROYL-COA DESATURASE INHIBITOR SUPPRESSES IDH MUTANT GLIOMA GROWTH VIA ENHANCING LIPOLYSIS

BACKGROUND

Mutant isocitrate dehydrogenase (IDH) produces 2-hydroxyglutarate (D2HG) and causes metabolic reprograming, but so far, little is known about the role of mutant IDH and D2HG in de novo lipogenesis and fatty acids synthesis. In this study, to develop a feasible drug for IDH mutant glioma, we targeted Stearoyl-CoA desaturase 1 (SCD1) catalyzing the biosynthesis of monosaturated fatty acids (MUFA) to suppress IDH mutant glioma progression. Materials and

METHODS

We prepared genetically engineered glioma cell lines (U251 wild type: U251WT and U251 IDHR132H mutant: U251RH), normal human astrocytes (empty vector induced-NHA: NHAEV and IDHR132H mutant: NHARH) and patient derived cell lines. Lipid metabolic analysis was conducted by using LC-MS, and functional analysis for the role of SCD1 expression was investigated by RNA sequence and Western-blotting.

RESULTS

LC-MS analysis of extracted Endoplasmic Reticulum revealed that there was significantly higher amount of MUFA in IDH mutant than wild type. SCD1 expression was increased in IDH mutant compared to wild type due to D2HG-mediated upregulation of SCD1 in IDH mutant. Therefore, IDH mutant in which SCD1 expression level was higher than wild type indicated high sensitivity to SCD inhibitor, and apoptosis was highly induced in IDH mutant compared to wild type. RNA sequencing was performed in U251RH treated with SCD inhibitor compared to U251RH treated with DMSO, and lipid droplet metabolism-associated RNA expression was significantly changed in SCD inhibitor-treated U251RH. Based on the RNA sequence data, we checked lipid droplet in U251RH with presence or absence of SCD inhibitor, and lipolysis was induced by SCD inhibitor treatment, suggesting that SCD inhibition is associated with the apoptosis in IDH mutant via enhanced lipolysis mechanism.

CONCLUSIONS

D2HG produced in IDH mutant glioma directly induces SCD1 expression and enhances sensitivity to SCD inhibitor, which suggests that SCD inhibitor would be IDH mutant glioma-specific treatment strategy.

PATH-04. CURRENT STATUS AND PROSPECTS OF MALIGNANT BRAIN TUMOR TREATMENT IN CANCER GENOMIC MEDICINE

INTRODUCTION

The cancer gene panel test was covered by insurance in June 2019 in Japan. Our institution started the test in May 2020 and has experienced 16 cases. We will report on the current status and future prospects.

METHODS

The subjects were 16 patients (Average age 48.4) who underwent the cancer gene panel test with FoundationOne CDx. [Results] The cases included 9 glioblastomas, 3 anaplastic astrocytomas, 2 anaplastic oligodendrogliomas, an ependymoma, and a pituitary carcinoma. On average, 11.0 genetic changes were detected totally, oncogene mutations were 4.4, and gene mutations of unknown relevance to cancer were 5.6. Major oncogene mutations were IDH1 mutation in 5 cases, ATRX mutation in 2 cases, TP53 mutation in 9 cases, CDKN2A/2B mutation in 5 cases, and BRAF V600E mutation in 1 case. Based on our results, a 25-year-old man with BRAF V600E mutation and a 47-year-old male with IDH1 mutation could be given molecular-targeted drugs. Furthermore, a 59-year-old male with pituitary carcinoma had more than 10 mut/Mb in tumor mutational burden (TMB), indicating that anti-PD-1 antibody drugs can be administered. The chance of finding an appropriate drug by cancer gene panel test is approximately 10-20%. In cases that are resistant to standard treatment, the benefits can be expected if the drugs associated with the cancer gene panel test can be used.

CONCLUSIONS

Comprehensive cancer gene panel test has the potential to provide personalized medicine. And we suggest that the active use of cancer gene panel test may contribute to the development of new drugs with high response rates and the improvement of prognosis.

Efficacy of HSV-TK/GCV system suicide gene therapy using SHED expressing modified HSV-TK against lung cancer brain metastases

Lung cancer is one of the most common cancers, and the number of patients with intracranial metastases is increasing. Previously, we developed an enzyme prodrug suicide gene therapy based on the herpes simplex virus thymidine kinase (HSV-TK)/ganciclovir (GCV) system using various mesenchymal stem cells to induce apoptosis in malignant gliomas through bystander killing effects. Here, we describe stem cells from human exfoliated deciduous teeth (SHED) as gene vehicles of the TK/GCV system against a brain metastasis model of non-small cell lung cancer (NSCLC). We introduced the A168H mutant TK (TK^A168H) into SHED to establish the therapeutic cells because of the latent toxicity of wild type. SHED expressing TK^A168H (SHED-TK) exhibited chemotaxis to the conditioned medium of NSCLC and migrated toward implanted NSCLC in vivo. SHED-TK demonstrated a strong bystander effect in vitro and in vivo and completely eradicated H1299 NSCLC in the brain. SHED-TK cells implanted intratumorally followed by GCV administration significantly suppressed the growth of H1299 and improved survival time. These results indicate that the TK^A168H variant is suitable for establishing therapeutic cells and that intratumoral injection of SHED-TK followed by GCV administration may be a useful strategy for therapeutic approaches.

[Prevention of and Countermeasures for Surgical Site Infection in the Field of Skull Base Surgery]

In neurosurgery, perioperative surgical site infection(SSI)is associated with complicated postoperative management, prolonged hospital stay, and patient stress. In this article, we review SSI in the field of skull base surgery, including endoscopic endonasal surgery, and discuss ways to prevent SSI. In a craniotomy, in which the frontal sinus is revealed, prevention of cerebrospinal fluid(CSF)leakage by reliable repair of the dura and frontal sinus reduces SSI. In addition, prevention of postoperative CSF leakage by reliable skull base reconstruction in endoscopic endonasal surgery contributes to the prevention of SSI. Prophylactic antibiotics are often reported to be useful, and cephalosporin or sulbactam/ampicillin intravenous injections are generally used. There are insufficient data to recommend lumbar drainage for the management of SSI and postoperative CSF leak. Skull base surgery is often a clean-contaminated surgery, and serious complications can be prevented by proper understanding and performance of the appropriate method as required. However, no studies with a high level of evidence on SSI in the field of skull base surgery exist. New large randomized controlled trials are expected to evaluate the efficacy of prophylactic antibiotics in skull base surgery.

Molecular Mechanisms and Clinical Challenges of Glioma Invasion

Glioma is the most common primary brain tumor, and its prognosis is poor. Glioma cells are highly invasive to the brain parenchyma. It is difficult to achieve complete resection due to the nature of the brain tissue, and tumors that invade the parenchyma often recur. The invasiveness of tumor cells has been studied from various aspects, and the related molecular mechanisms are gradually becoming clear. Cell adhesion factors and extracellular matrix factors have a strong influence on glioma invasion. The molecular mechanisms that enhance the invasiveness of glioma stem cells, which have been investigated in recent years, have also been clarified. In addition, it has been discussed from both basic and clinical perspectives that current therapies can alter the invasiveness of tumors, and there is a need to develop therapeutic approaches to glioma invasion in the future. In this review, we will summarize the factors that influence the invasiveness of glioma based on the environment of tumor cells and tissues, and describe the impact of the treatment of glioma on invasion in terms of molecular biology, and the novel therapies for invasion that are currently being developed.

A novel technique for fence-post tube placement in glioma using the robot-guided frameless neuronavigation technique under exoscope surgery: patient series

BACKGROUND

Robotic technology is increasingly used in neurosurgery. The authors reported a new technique for fence-post tube placement using robot-guided frameless stereotaxic technology with neuronavigation in patients with glioma.

OBSERVATIONS

Surgery was performed using the StealthStation S8 linked to the Stealth Autoguide cranial robotic guidance platform and a high-resolution three-dimensional (3D) surgical microscope. A surgical plan was created to determine the removal area using fence-post tube placement at the tumor and normal brain tissue boundary. Using this surgical plan, the robotic system allowed quick and accurate fence-post tube positioning, automatic alignment of the needle insertion and measurement positions in the brain, and quick and accurate puncture needle insertion into the brain tumor. Use of a ventricular drainage tube for the outer needle cylinder allowed placement of the puncture needle in a single operation. Furthermore, use of a high-resolution 3D exoscope allowed the surgeon to simultaneously view the surgical field image and the navigation screen with minimal line-of-sight movement, which improved operative safety. The position memory function of the 3D exoscope allowed easy switching between the exoscope and the microscope and optimal field of view adjustment.

LESSONS

Fence-post tube placement using robot-guided frameless stereotaxic technology, neuronavigation, and an exoscope allows precise glioma resection.

CBMS-3 Potent bystander effect in suicide gene therapy using genetically engineered stem cells from human exfoliated deciduous teeth

HSV thymidine kinase (TK)/ganciclovir (GCV) has a long history of application in malignant glioma and we have previously demonstrated its bystander effect on gliomas using several stem cell types as a vehicle. The main reason for applying stem cells is that they have a unique tumor-trophic activity that allows them to deliver TK genes efficiently to nearby the tumor. Stem cells from human exfoliated deciduous teeth (SHED) are mesenchymal stem cells easily harvested from dental pulp and no studies have reported suicide gene therapy using SHED as a carrier for malignant gliomas. For transduction of SHED with the HSVTK gene (SHEDTK), we used HSVTK retrovirus-producing cells.In vitro experiments showed a significant migration ability of SHEDTK toward tumor-conditioned medium and representative tumor growth factors. We also detected a significant bystander effect of SHEDTK on gliomas in the presence of GCV. In vitro time-lapse imaging showed that both SHEDTK and glioma cells underwent gradual morphological apoptosis and activation of caspase 3/7 was observed in both cell types. In intracranial tumor models using nude mice, SHEDTK migrated around the U87 cell mass implanted in the contralateral hemisphere. Additionally, coculture suspensions of SHEDTK and U87-luciferase cells were xeno-transplanted followed by intraperitoneal administration of GCV for 10 days. All mice of treatment group survived for more than 100 days, whereas those treated without GCV died of tumor growth with median survival of 42 days after tumor implantation. Furthermore, pre-existing intracranial U87 model mice were injected intratumorally with SHEDTK followed by GCV administration as described above. The tumor volume was significantly reduced during the treatment period, and over-all surivial in treatment group is prolonged significantly to that of control groups. These results indicate that SHEDTK-based suicide gene therapy might offer a new promising therapeutic modality for human malignant gliomas.

ACT-8 Current status and prospects for the treatment of malignant glioma using cancer gene panel tests

Introduction: The cancer gene panel test was covered by insurance in June 2019. Our institution started the test in May 2020 and has experienced 10 cases, so we will report on the current status and future prospects. Methods: The subjects were 10 patients who underwent the cancer gene panel test using FoundationOne CDx. Results:The cases included 8 glioblastomas, an anaplastic astrocytoma, and an anaplastic oligodendroglioma. The total number of tumor mutational burden (TMB) was judged to be low in all cases, and the microsatellite instability test (MSI) showed no instability in all cases (MSI-Stable). The total number of genetic changes detected was 11 ± 5.0, oncogene mutations were 5.3 ± 2.4, and gene mutations of unknown relevance to cancer were 5.7 ± 2.8. Major oncogene mutations were IDH1 mutation in 4 cases, ATRX mutation in 2 cases, TP53 mutation in 6 cases, and BRAF V600E mutation in 1 case. Based on the test results, a 25-year-old man with BRAF V600E mutation was initiated into the NCCH1901 study (Patient-Proposed Healthcare Services). A case with IDH1 mutation (47-year-old male) entered a phase I clinical trial of a mutant IDH1 inhibitor. It is estimated that the chance of finding an appropriate drug by cancer gene panel test is about 10–20%. However, in cases that are resistant to standard treatment, the benefits can be expected if the drugs associated with the cancer gene panel test can be used. Conclusions: Although Malignant gliomas are often TMB-low and MSI-stable and the response rate to molecular-targeted drugs and other therapies is not high, there are some cases that can be salvaged by performing the cancer gene panel test. It is suggested that the active use of cancer gene panel test may contribute to the development of new drugs with high response rates and the improvement of prognosis.

[Gene Therapy and Viral Therapy for Malignant Glioma]

Malignant gliomas have a poor prognosis despite advances in surgical procedures, radiotherapy, and the emergence of new treatments have improved outcomes. One of these new treatments is gene therapy, which has been developed as a new therapeutic strategy. Recently, new methods and approaches have been developed. Gene therapy involves the introduction of genes or cells into a glioma, or the human body, to treat gliomas; various genes such as cancer-suppressing genes, immunomodulation cytokine-related genes, and suicide genes are used in this treatment. Viral therapy is a treatment that oncolytic viral replicates in tumor cells to destroy tumors. Various viral genes can also be used as therapeutic genes. Currently, the most well-studied and accumulated viruses are adenoviruses and HSV-1. Various clinical trials have been conducted using gene therapy and viral therapy, some of which are scheduled to be approved in the near future. Gene therapy and viral therapy have dramatically improved and have developed progressively since their first clinical use.

NI-01 Usefulness of preoperative evaluation of glioma elasticity by the magnetic resonance elastography

Introduction: The elasticity of intracranial tumors is difficult to assess non-invasively because the lesion is surrounded by the skull. Therefore, intracranial tumors have not been verified before surgery in terms of elastic modulus. Magnetic resonance elastography (MRE) is an epoch-making method capable of non-invasively imaging the elasticity of internal organs. We have examined the elasticity of meningiomas and pituitary adenomas and reported their usefulness. This time, we measured the glioma elasticity and verified usefulness of MRE.

Method: Twenty-four gliomas (mean age 51.8±15.7 years, male: female = 17: 7) who underwent tumor resection after MRE imaging from July 2017 to May 2020 were targeted. The average elasticity was measured as an evaluation of tumor elastic modulus by MRE. Gliomas were divided into a low-grade glioma group (LGG: Grade 1, 2) and a high-grade glioma group (HGG: Grade 3, 4). Then, a comparative statistical study was conducted.

Results: The average values of the average elasticity of LGG group (9 cases) and HGG group (15 cases) were 1.8±0.8 kPa and 2.5±0.8 kPa, respectively. The average elasticity was significantly higher in the HGG group (p=0.023). In the ROC analysis, the cutoff value was 2.1 kPa (sensitivity 70%, specificity 70%). Therefore, it was suggested that the tumor is likely to be HGG when the average elasticity is 2.1 kPa or more.

Discussion: The glioma elasticity by preoperative MRE was significantly higher in the HGG group. Based on actual surgical experience, the tumor seems to be hard in the HGG group, and it was judged to be consistent with this our MRE research. The preoperative evaluation of glioma elasticity by MRE was considered useful, and it might help in planning a surgical strategy considering malignant grade.

Nicotine does not affect stem cell properties requisite for suicide gene therapy against glioma

OBJECTIVE: 

Glioblastoma is one of the most lethal tumors in adult central nervous system with a median survival of a year and half and effective therapeutic strategy is urgently needed. For that reason, stem cell-based suicide gene therapies have attracted much interest because of potent tumor tropism of stem cells and bystander effect. In this current clinical situation, stem cells are promising delivery tool of suicide genes for glioma therapy. Since habitual cigarette smoking still prevails worldwide, we investigated the effect of nicotine on stem cell tropism toward glioma and gap junctional intercellular communication (GJIC) function between glioma and stem cells, both of which are important for suicide gene therapies. Methods: Mouse induced pluripotent stem cell-derived neural stem cells (iPS-NSCs) and human dental pulp mesenchymal stem cells (DPSCs) were used. The effect of nicotine on tumor tropism to glioma-conditioned medium (CM) at a non-cytotoxic concentration was assessed with Matrigel invasion assay. Nicotine effect on GJIC was assessed with the scrape loading/dye transfer (SL/DT) assay for co-culture of glioma and stem cells and the parachute assay among glioma cells using high-content analysis. Results: Tumor tropism of iPS-NSCs toward GL261-CM and DPSCs toward U251-CM was not affected by nicotine (0.1 and 1 µM). Nicotine at the concentrations equivalent to habitual smoking (1 µM) did not affect GJIC of iPS-NSC/GL261 and DPSC/U251 and GJIC among each glioma cells. Conclusions: The study demonstrated that non-cytotoxic concentrations of nicotine did not significantly change the stem cell properties requisite for stem cell-based suicide gene therapy.

CBMS-08 INVESTIGATION FOR NICOTINIC EFFECTS ON STEM CELL’S PROPERTY IN HSV-TK/GCV GENE THERAPY

BACKGROUND

Herpes simplex virus-thymidine kinase/ganciclovir (HSV-tk/GCV) system is one of feasible therapeutic strategies for defeating malignant gliomas. Stem cells with intrinsic tumor tropism are used for suicide gene vehicles, which make this therapy further realistic. Nicotine is known to affect cellular migration capacity in variety types of cells but whether nicotine impacts on stem cells’ migration capacity to gliomas is not scrutinized. In this research, we investigated nicotinic impact on stem cells’ properties including tumor tropism and gap junctional intercellular communication (GJIC), which is crucial to this therapeutic strategy.

METHODS

Mouse induced pluripotent stem cell (iPSC)-derived neural stem cells (miPS-NSCs) and human dental pulp mesenchymal stem cells (hDPSCs) were used. Nicotine cytotoxicity for 24 hours was evaluated by MTT assay for stem cells and glioma cells; GS-9L and C6 (rat), GL261 (mouse), U251 and U87 (human). Tumor tropism to glioma-conditioned medium (CM) with or without non-toxic nicotine concentrations was assessed using Matrigel Invasion Chamber. Nicotine effect on GJIC was assessed with scrape loading/dye transfer assay (SL/DT assay) for co-culture of stem cells and glioma cells (stem cell/glioma cell) or parachute assay for glioma cells alone using high-content analysis.

RESULTS

MTT assay revealed 1 μM of nicotine, equivalent to serum nicotine concentration in habitual smoking, is the maximum safe concentration for stem cells and glioma cells. Tumor tropism (miPS-NSCs to GL261-CM, hDPSCs to U251- or U87-CM) and GJIC of co-culture of stem cells and glioma cells (miPS-NSC/GL261, hDPSC/U251) or glioma cells alone (GS-9L, C6, GL261 and U251) were not affected by 1 μM of nicotine.

CONCLUSIONS

Physiological nicotine presence did not affect (1) stem cell’s tumor tropism to gliomas and (2) GJIC between stem cells and glioma cells or within glioma cells. HSV-tk/GCV therapy may retain its therapeutic efficacy against gliomas even under physiological nicotine concentrations.

Acute and chronic hemorrhage from radiation-induced cavernous malformation associated with late-delayed radiation necrosis in long surviving glioma patients: A case report

Although radiation therapy is a standard treatment strategy for patients with glioma, its delayed complications are not clearly understood. Radiation-induced cavernous malformation (RICM) is one of the complications in the delayed phase following radiation therapy, which usually occurs in children. Herein we present three cases of RICM with radiation necrosis in long surviving adult glioma patients, 2 with oligoastrocytoma and one with anaplastic ependymoma. Two of three patients had received an obvious overdose of radiation by additional stereotactic radiation therapy. Repeated episodes of either acute or chronic hemorrhages from RICM worsened the neurological symptoms in all cases. The interval between the last irradiation and the occurrence of symptoms was 45-173 months. The presence of hypointense rim on FLAIR or T2* on magnetic resonance imaging, which resembles the appearance of sporadic cavernous malformations, could be helpful in differentiating RICM from tumor recurrence. Surgical resection was effective in alleviating the symptoms. Microscopically, RICM is a vascular lesion with vulnerable vessels, which are observed in the center of the radiation necrosis. Repeated hemorrhages from these vessels cause either gradual or sudden worsening of neurological symptoms. Therefore, radiation overdose, which results in radiation injury, should be avoided in low grade glioma patients, who could potentially survive for a long period.

Fluid-Blood Level and Hematoma Expansion in a Cerebral Amyloid Angiopathy-Associated Intracerebral Hematoma

Patient: Male, 77

Final Diagnosis: Cerebral amyloid angiopathy

Symptoms: Aphasia • hemiparesis

Medication: —

Clinical Procedure: Hematoma evacuation

Specialty: Neurosurgery

Expression of Periostin in Patients with Non-Small Cell Lung Cancer: Correlation with Angiogenesis and Lymphangiogenesis

The aim of this study was to evaluate periostin expression measured immunohistochemically in patients with non-small cell lung cancer (NSCLC) and to determine its association with clinical features, prognosis, angiogenesis, and lymphangiogenesis. We investigated periostin expression in a series of 88 patients with NSCLC. We also determined whether expression of periostin correlated with microvessel density and lymphatic microvessel density. Periostin was expressed in 42% of 88 patients. Its expression was significantly correlated with tumor size, lymph node metastasis, disease stage, and lymphatic invasion (p=0.0128, 0.0015, 0.0310 and 0.0273, respectively). There also was a significant relation between periostin expression and microvessel density and lymphatic microvessel density (all p<0.0001). Five-year survival rates were better in patients with negative periostin expression than in those with positive periostin expression (p=0.0044). Periostin expression was not significant in a multivariate additive model. Our findings show that periostin correlates with increased tumor progression and a worse prognosis in NSCLC, as well as with angiogenesis and lymphangiogenesis.

Genetically Engineered Multilineage-Differentiating Stress-Enduring Cells as Cellular Vehicles against Malignant Gliomas

Malignant glioma, the most common malignant brain tumor in adults, is difficult to treat due to its aggressive invasive nature. Enzyme/prodrug suicide gene therapy based on the herpes simplex virus thymidine kinase (HSVtk)/ganciclovir (GCV) system is an efficient strategy for treating malignant gliomas. In the present study, we evaluated treatment with multilineage-differentiating stress-enduring (Muse) cells, which are endogenous non-tumorigenic pluripotent-like stem cells that are easily collectable from the bone marrow as SSEA-3⁺ cells, as carriers of the HSVtk gene. Human Muse cells showed potent migratory activity toward glioma cells both in vitro and in vivo. HSVtk gene-transduced Muse cells (Muse-tk cells) at a cell number of only 1/32 that of U87 human glioma cells completely eradicated U87 gliomas in nude mouse brains, showing a robust in vivo bystander effect. Pre-existing intracranial U87 gliomas in nude mouse brains injected intratumorally with Muse-tk cells followed by intraperitoneal GCV administration were significantly reduced in size within 2 weeks, and 4 of 10 treated mice survived over 200 days. These findings suggest that intratumoral Muse-tk cell injection followed by systemic GCV administration is safe and effective and that allogeneic Muse-tk cell-medicated suicide gene therapy for malignant glioma is clinically feasible.

The pressure sensitivity of wrinkled B-doped nanocrystalline diamond membranes

Nanocrystalline diamond (NCD) membranes are promising candidates for use as sensitive pressure sensors. NCD membranes are able to withstand harsh conditions and are easily fabricated on glass. In this study the sensitivity of heavily boron doped NCD (B:NCD) pressure sensors is evaluated with respect to different types of supporting glass substrates, doping levels and membrane sizes. Higher pressure sensing sensitivities are obtained for membranes on Corning Eagle 2000 glass, which have a better match in thermal expansion coefficient with diamond compared to those on Schott AF45 glass. In addition, it is shown that larger and more heavily doped membranes are more sensitive. After fabrication of the membranes, the stress in the B:NCD films is released by the emergence of wrinkles. A better match between the thermal expansion coefficient of the NCD layer and the underlying substrate results in less stress and a smaller amount of wrinkles as confirmed by Raman spectroscopy and 3D surface imaging.

Multi-tube area detector developed for reactor small-angle neutron scattering spectrometer SANS-J-II

A newly developed multi-tube area detector for a small-angle neutron scattering (SANS) spectrometer (SANS-J-II) at the research reactor JRR-3 in Tokai, Japan, has been implementedviathe use of one-dimensional position-sensitive3He detectors (tubes). Ninety-six active tubes of 8 mm in diameter and 650 and 580 mm in length were filled with 15 atm (1.52 MPa) of3He and aligned vertically parallel in order to cover a sufficiently large area for small-angle scattering measurement. These tubes are enclosed in an air chamber together with neutron encode and GATENET modules (VME boards), which compose a standard data acquisition system for the spallation neutron source of the Japan Proton Accelerator Research Complex. This system facilitates the acquisition of time-of-flight neutron event data. The multi-tube detector is mounted on a truck moving in a vacuum chamber of the SANS spectrometer. After discriminating noise originating from γ-rays, and calibrating the positions and sensitivities of individual tubes, the resolution was determined (i.e.channel widths along parallel and vertical directions along a tube). The counting rate of one tube was determined to be 1.4 × 103counts per second with a counting loss of 1%. This implies that the new detector, composed of 96 tubes, can detect more than 105neutrons per second with a counting loss of 1%. To demonstrate its use, small-angle scattering originating from a diblock copolymer film with a highly oriented lamellar microdomain was observed. The data acquisition in event mode has a great advantage in time-resolved measurements that are synchronized with external stimuli imposed on a sample.

The present indication and future of deep brain stimulation

The use of electrical stimulation to treat pain in human disease dates back to ancient Rome or Greece. Modern deep brain stimulation (DBS) was initially applied for pain treatment in the 1960s, and was later used to treat movement disorders in the 1990s. After recognition of DBS as a therapy for central nervous system (CNS) circuit disorders, DBS use showed drastic increase in terms of adaptability to disease and the patient’s population. More than 100,000 patients have received DBS therapy worldwide. The established indications for DBS are Parkinson’s disease, tremor, and dystonia, whereas global indications of DBS expanded to other neuronal diseases or disorders such as neuropathic pain, epilepsy, and tinnitus. DBS is also experimentally used to manage cognitive disorders and psychiatric diseases such as major depression, obsessive-compulsive disorder (OCD), Tourette’s syndrome, and eating disorders. The importance of ethics and conflicts surrounding the regulation and freedom of choice associated with the application of DBS therapy for new diseases or disorders is increasing. These debates are centered on the use of DBS to treat new diseases and disorders as well as its potential to enhance ability in normal healthy individuals. Here we present three issues that need to be addressed in the future: (1) elucidation of the mechanisms of DBS, (2) development of new DBS methods, and (3) miniaturization of the DBS system. With the use of DBS, functional neurosurgery entered into the new era that man can manage and control the brain circuit to treat intractable neuronal diseases and disorders.

Potent tumor tropism of induced pluripotent stem cells and induced pluripotent stem cell-derived neural stem cells in the mouse intracerebral glioma model

Although neural and mesenchymal stem cells have been well-known to have a strong glioma tropism, this activity in induced pluripotent stem cells (iPSCs) has not yet been fully studied. In the present study, we tested tumor tropic activity of mouse iPSCs and neural stem cells derived from the iPSC (iPS-NSCs) using in vitro Matrigel invasion chamber assay and in vivo mouse intracranial tumor model. Both iPSC and iPS-NSC had a similar potent in vitro tropism for glioma conditioned media. The migrated iPSCs to the gliomas kept expressing Nanog-GFP gene, suggesting no neuronal or glial differentiation. iPSCs or iPS-NSCs labeled with 5-bromo-2-deoxyuridine were intracranially implanted in the contralateral hemisphere to the GL261 glioma cell implantation in the allogeneic C57BL/6 mouse. Active migration of both stem cells was observed 7 days after implantation. Again, the iPSCs located in the tumor area expressed Nanog-GFP gene, suggesting that the migrated cells were still iPSCs. These findings demonstrated that both iPSCs and iPS-NSCs had potent glioma tropism and could be candidates as vehicles in stem cell-based glioma therapy.

Primary neurolymphomatosis of the lower cranial nerves presenting as Dysphagia and hoarseness: a case report

Primary neurolymphomatosis is an extremely rare tumor. We report the case of a 74-year-old patient presenting with dysphagia and hoarseness. Initial contrast-enhanced computed tomography of the head, neck, and chest did not reveal any lesions. His symptoms improved with short-term administration of prednisone but recurred and deteriorated. Magnetic resonance (MR) imaging revealed a tumor along the ninth and tenth cranial nerves across the jugular foramen. Fluorine-18 fluorodeoxyglucose positron emission tomography indicated this was a primary tumor. Repeated MR imaging after 2 months revealed considerable tumor enlargement. A left suboccipital craniotomy was performed to remove the tumor that infiltrated the ninth and tenth cranial nerves. The histopathologic diagnosis was diffuse large B-cell lymphoma. Although focal radiation therapy was administered to ensure complete eradication of the tumor, the patient died of aspiration pneumonia with systemic metastasis. To our knowledge, this is the first reported case of primary neurolymphomatosis in the lower cranial nerves.

Usefulness of intraoperative monitoring of visual evoked potentials in transsphenoidal surgery

Postoperative visual outcome is a major concern in transsphenoidal surgery (TSS). Intraoperative visual evoked potential (VEP) monitoring has been reported to have little usefulness in predicting postoperative visual outcome. To re-evaluate its usefulness, we adapted a high-power light-stimulating device with electroretinography (ERG) to ascertain retinal light stimulation. Intraoperative VEP monitoring was conducted in TSSs in 33 consecutive patients with sellar and parasellar tumors under total venous anesthesia. The detectability rates of N75, P100, and N135 were 94.0%, 85.0%, and 79.0%, respectively. The mean latencies and amplitudes of N75, P100, and N135 were 76.8 ± 6.4 msec and 4.6 ± 1.8 μV, 98.0 ± 8.6 msec and 5.0 ± 3.4 μV, and 122.1 ± 16.3 msec and 5.7 ± 2.8 μV, respectively. The amplitude was defined as the voltage difference from N75 to P100 or P100 to N135. The criterion for amplitude changes was defined as a > 50% increase or 50% decrease in amplitude compared to the control level. The surgeon was immediately alerted when the VEP changed beyond these thresholds, and the surgical manipulations were stopped until the VEP recovered. Among the 28 cases with evaluable VEP recordings, the VEP amplitudes were stable in 23 cases and transiently decreased in 4 cases. In these 4 cases, no postoperative vision deterioration was observed. One patient, whose VEP amplitude decreased without subsequent recovery, developed vision deterioration. Intraoperative VEP monitoring with ERG to ascertain retinal light stimulation by the new stimulus device was reliable and feasible in preserving visual function in patients undergoing TSS.

Usefulness of intraoperative monitoring of visual evoked potentials in transsphenoidal surgery

Postoperative visual outcome is a major concern in transsphenoidal surgery (TSS). Intraoperative visual evoked potential (VEP) monitoring has been reported to have little usefulness in predicting postoperative visual outcome. To re-evaluate its usefulness, we adapted a high-power light-stimulating device with electroretinography (ERG) to ascertain retinal light stimulation. Intraoperative VEP monitoring was conducted in TSSs in 33 consecutive patients with sellar and parasellar tumors under total venous anesthesia. The detectability rates of N75, P100, and N135 were 94.0%, 85.0%, and 79.0%, respectively. The mean latencies and amplitudes of N75, P100, and N135 were 76.8±6.4 msec and 4.6±1.8 μV, 98.0±8.6 msec and 5.0±3.4 μV, and 122.1±16.3 msec and 5.7±2.8 μV, respectively. The amplitude was defined as the voltage difference from N75 to P100 or P100 to N135. The criterion for amplitude changes was defined as a >50% increase or 50% decrease in amplitude compared to the control level. The surgeon was immediately alerted when the VEP changed beyond these thresholds, and the surgical manipulations were stopped until the VEP recovered. Among the 28 cases with evaluable VEP recordings, the VEP amplitudes were stable in 23 cases and transiently decreased in 4 cases. In these 4 cases, no postoperative vision deterioration was observed. One patient, whose VEP amplitude decreased without subsequent recovery, developed vision deterioration. Intraoperative VEP monitoring with ERG to ascertain retinal light stimulation by the new stimulus device was reliable and feasible in preserving visual function in patients undergoing TSS.

Arterial spin-labeled perfusion imaging reflects vascular density in nonfunctioning pituitary macroadenomas

BACKGROUND AND PURPOSE

Angiogenesis is very important in clinical features of pituitary adenomas. We investigated the relationship between the blood flow of nonfunctioning pituitary macroadenomas measured by arterial spin-labeled perfusion imaging and the microvessel attenuation of the tissue.

MATERIALS AND METHODS

Conventional MR imaging with contrast-enhanced T1WI and arterial spin-labeled perfusion imaging were performed before surgery in 11 consecutive patients with nonfunctioning pituitary macroadenomas. ROIs were drawn on the tumors, and the degrees of enhancement were calculated by dividing the signal intensity on the contrast-enhanced T1WI by that on the nonenhanced TIWI. As an index of tumor perfusion, a quantitative analysis was performed by using normalized tumor blood flow values calculated by dividing the mean value of the tumor region of interest by the mean region of interest values in the 2 cerebellar hemispheres. The relative microvessel attenuation was determined as the total microvessel wall area divided by the entire tissue area on CD-31-stained specimens. The degree of enhancement and the normalized tumor blood flow values were compared with relative microvessel attenuation. Additionally, intra- and postoperative tumor hemorrhages were visually graded.

RESULTS

The degree of enhancement was not correlated with relative microvessel attenuation. Statistically significant correlations were observed between normalized tumor blood flow values and relative microvessel attenuation (P < .05). At surgery, 3 cases were visually determined to be hypervascular tumors, and 1 of these cases had symptomatic postoperative hemorrhage. A statistically significant difference in normalized tumor blood flow values was observed visually between the intraoperative hypovascular and hypervascular groups (P < .05).

CONCLUSIONS

Arterial spin-labeled perfusion imaging reflects the vascular density of nonfunctioning pituitary macroadenomas, which may be useful in the preoperative prediction of intra- and postoperative tumor hemorrhage.

Detecting and polarizing nuclear spins with double resonance on a single electron spin

We report the detection and polarization of nuclear spins in diamond at room temperature by using a single nitrogen-vacancy (NV) center. We use Hartmann-Hahn double resonance to coherently enhance the signal from a single nuclear spin while decoupling from the noisy spin bath, which otherwise limits the detection sensitivity. As a proof of principle, we (i) observe coherent oscillations between the NV center and a weakly coupled nuclear spin and (ii) demonstrate nuclear-bath cooling, which prolongs the coherence time of the NV sensor by more than a factor of 5. Our results provide a route to nanometer scale magnetic resonance imaging and novel quantum information processing protocols.

Myelopathy due to multilevel cervical canal stenosis with Forestier disease: case report

A 56-year-old woman presented with multilevel myelopathy associated with Forestier disease (FD). The patient was hospitalized for dysphagia, bilateral shoulder pain, and progressive gait disturbance. The diagnosis was confirmed by radiography and magnetic resonance imaging which demonstrated coalescent anterior osteophyte formation extending from C2 to C7 with atlanto-axial dislocation and persistence of mobility at C3-4, and a hyperintense area in the spinal cord at the C1 and C3-4 levels on T(2)-weighted images. Dynamic radiography showed no instability at the C1 and C3-4 levels. Decompressive laminectomy of the atlas, dome-like laminectomy, and facet fusion at C3-4 were performed, resulting in symptomatic improvement. Myelopathy is very rare in patients with FD and is due to mechanical stress at the level where mobility persists. Strategic intervention should be considered based on evaluation of mobile levels and stenotic lesions.

Protein tyrosine phosphatases

Protein tyrosine phosphatases (PTPases) balance the action of tyrosine kinases to maintain a set level of cellular tyrosine phosphorylation. Increases in tyrosine phosphorylation produced by transformation with constitutively active tyrosine kinases can initiate cellular proliferation. PTPases may act as tumor suppressors to counteract the transforming potential of oncogenic kinases. However, recent evidence suggests that PTPases have the potential to act as positive mediators of mitogenic signaling. If PTPases are acting as tumor suppressors, the expression of an inactive PTPase may cause an increase in overall tyrosine phosphorylation of cellular proteins, resulting in cellular transformation. Alternatively, overexpression of PTPases that play a positive role in signal transduction might also lead to proliferation. The role that each PTPase plays may depend in the cellular context in which it is expressed.

Visualization of ATP with luciferin-luciferase reaction in mouse skeletal muscles using an "in vivo cryotechnique"

Adenosine triphosphate (ATP) is a well-known energy source for muscle contraction. In this study, to visualize localization of ATP, a luciferin-luciferase reaction (LLR) was performed in mouse skeletal muscle with an "in vivo cryotechnique" (IVCT). First, to confirm if ATP molecules could be trapped and detected after glutaraldehyde (GA) treatment, ATP was directly attached to glass slides with GA, and LLR was performed. The LLR was clearly detected as an intentional design of the ATP attachment. The intensity of the light unit by LLR was correlated with the concentration of the GA-treated ATP in vitro. Next, LLR was evaluated in mouse skeletal muscles with IVCT followed by freeze-substitution fixation (FS) in acetone-containing GA. In such tissue sections the histological structure was well maintained, and the intensity of LLR in areas between muscle fibers and connective tissues was different. Moreover, differences in LLR among muscle fibers were also detected. For the IVCT-FS tissue sections, diaminobenzidine (DAB) reactions were clearly detected in type I muscle fibers and erythrocytes in capillaries, which demonstrated flow shape. Thus, it became possible to perform microscopic evaluation of the numbers of ATP molecules in the mouse skeletal muscles with IVCT, which mostly reflect living states.

Bystander effect in glioma suicide gene therapy using bone marrow stromal cells

An established rat intracranial glioma was successfully treated through the tumoricidal bystander effect generated by intratumoral injection of rat bone marrow stromal cells (BMSCs) transduced with the herpes simplex virus-thymidine kinase gene (BMSCtk cells) followed by systemic ganciclovir administration. In the present study, we tested the bystander effect of this treatment strategy when using human BMSCs as the vector cells. Human BMSCtk cells were mixed with various kinds of brain tumor cell lines (human and rat glioma cells) and examined in vitro and in vivo tumoricidal bystander effects, by co-culture study and co-implantation study in the nude mouse, respectively. A significant in vitro bystander effect was observed between human BMSCtk cells and any of the tumor cells examined in the ganciclovir-containing medium. A potent in vivo bystander effect against human and rat glioma cells was also demonstrated when ganciclovir was administered. Migratory activity of the human BMSCs toward the tumor cells was enhanced by the conditioned media obtained from both human and rat glioma cells compared to the fresh media. The results of this study have demonstrated that the bystander effect generated by BMSCtk cells and ganciclovir is not cell type-specific, suggesting that the strategy would be quite feasible for clinical use.

Imaging mass spectrometry evaluation of the effects of various irrigation fluids in a rat model of postoperative cerebral edema

BACKGROUND

Using imaging mass spectrometry (IMS), we investigated the cerebral protective effect of an artificial cerebrospinal fluid (CSF), ARTCEREB (Artcereb, Otsuka Pharmaceutical Factory, Inc., Tokushima, Japan), as an irrigation and perfusion solution for neurosurgical procedures in a rat craniotomy model.

METHODS

Wounds created in the rat cerebral cortex were continuously irrigated with Artcereb, normal saline, or lactated Ringer's solution at a steady rate for 4 hours, after which brain tissue was collected. Brain slices were prepared and analyzed using IMS.

RESULTS

In tissue surrounding the injury, the signal intensity for Na adduct ions to phosphatidylcholine was high and that for K adduct ions to phosphatidylcholine was low. This is thought to reflect the level of water retention in brain cells and to be a change accompanying edema. The signal intensity with Na adduct ions to phosphatidylcholine was significantly lower in the Artcereb group than in the physiological saline or lactated Ringer's solution groups.

CONCLUSIONS

IMS analysis in a rat craniotomy model indicated that the level of water retention in brain cells, calculated from the signal intensity of Na-adducted phosphatidylcholine around the wound area, was lowest in the Artcereb group, suggesting that artificial CSF that has similar composition and properties to human CSF can minimize edema in the brain surrounding the surgical wound.

Timing of ganciclovir administration in glioma gene therapy using HSVtk gene-transduced mesenchymal stem cells

BACKGROUND

An established C6 glioma was successfully treated with intratumoral injection of mesenchymal stem cells transduced with HSVtk gene (MSCtk) and systemic administration of ganciclovir (GCV). The best timing of GCV administration after the MSCtk implantation was studied.

MATERIALS AND METHODS

GCV administration was started from 2 days before and 1, 3 and 7 days after the MSCtk administration under both in vitro and in vivo conditions.

RESULTS

The C6 cells were completely eradicated in vitro when GCV administration was started from day -2, 1, and 3. Animals with intracranial tumor survived longer when GCV was administered earlier after MSCtk administration. This may, mainly, reflect the difference in the MSCtk/C6 ratio at the time of GCV administration because this ratio drastically decreases during the delay of GCV administration.

CONCLUSION

When using a slowly growing vector cell as MSCtk, GCV should be administered soon after MSCtk implantation.

Tumoricidal bystander effect in the suicide gene therapy using mesenchymal stem cells does not injure normal brain tissues

In our previous rat study, an established intracranial C6 glioma was successfully treated using intratumoral injection of mesenchymal stem cells transduced with the herpes simplex virus-thymidine kinase gene (MSCtk) and systemic administration of ganciclovir (GCV). In the present study, effect of the "bystander effect" associated with the MSCtk/GCV strategy on the background normal brain tissues was examined in both in vitro and in vivo conditions. Rat MSCtk and C6 glioma cells were mixed and seeded on the rat primary neuron and glia co-culture in the medium containing GCV to generate the bystander effect and the numbers of background cells were counted on day 0, 2 and 7. Though the number of MSCtk and C6 cells decreased rapidly due to the bystander effect, most of the neurons and glias survived on day 7. Next, rats were intracranially injected with the MSCtk and C6 cells and then intraperitoneally administered with GCV for 7days. No remarkable histological abnormality including apoptosis was observed in the background brain tissues near the injection site. The present study has demonstrated that the tumoricidal bystander effect does not injure the background normal brain tissue significantly and that the suicide gene therapies are sufficiently safe.