Intracranial Implantation Research Articles

Olfactory Ensheathing Cell Neurorestorotherapy for Amyotrophic Lateral Sclerosis Patients: Benefits from Multiple Transplantations

Our previous series of studies have proven that olfactory ensheathing cell (OEC) transplantation appears to be able to slow the rate of clinical progression after OEC transplantation in the first 4 months and cell intracranial (key points for neural network restoration, KPNNR) and/or intraspinal (impaired segments) implants provide benefit for patients (including both the bulbar onset and limb onset subtypes) with amyotrophic lateral sclerosis (ALS). Here we report the results of cell therapy in patients with ALS on the basis of long-term observation following multiple transplants. From March of 2003 to January of 2010, 507 ALS patients received our cellular treatment. Among them, 42 patients underwent further OEC therapy by the route of KPNNR for two or more times (two times in 35 patients, three times in 5 patients, four times in 1 patient, and five times in 1 patient). The time intervals are 13.1 (6-60) months between the first therapy and the second one, 15.2 (8-24) months between the second therapy and the third one, 16 (6-26) months between the third therapy and the fourth one, and 9 months between the fourth therapy and the fifth time. All of the patients exhibited partial neurological functional recovery after each cell-based administration. Firstly, the scores of the ALS Functional Rating Scale (ALS-FRS) and ALS Norris Scale increased by 2.6 + 2.4 (0-8) and 4.9 + 5.2 (0-20) after the first treatment, 1.1 + 1.3 (0-5) and 2.3 + 2.9 (0-13) after the second treatment, 1.1 + 1.5 (0-4), and 3.4 + 6.9 (0-19) after the third treatment, 0.0 + 0.0 (0-0), and 2.5 + 3.5 (0-5) after the fourth treatment, and 1 point after the fifth cellular therapy, which were evaluated by independent neurologists. Secondly, the majority of patients have achieved improvement in electromyogram (EMG) assessments after the first, second, third, and fourth cell transplantation. After the first treatment, among the 42 patients, 36 (85.7%) patients' EMG test results improved, the remaining 6 (14.3%) patients' EMG results showed no remarkable change. After the second treatment, of the 42 patients, 30 (71.4%) patients' EMG results improved, 11 (26.2%) patients showed no remarkable change, and 1 (2.4%) patient became worse. After the third treatment, out of the 7 patients, 4 (57.1%) patients improved, while the remaining 3 (42.9%) patients showed no change. Thirdly, the patients have partially recovered their breathing ability as demonstrated by pulmonary functional tests. After the first treatment, 20 (47.6%) patients' pulmonary function ameliorated. After the second treatment, 18 (42.9%) patients' pulmonary function improved. After the third treatment, 2 (28.6%) patients recovered some pulmonary function. After the fourth and fifth treatment, patients' pulmonary function did not reveal significant change. The results show that multiple doses of cellular therapy definitely serve as a positive role in the treatment of ALS. This repeated and periodic cell-based therapy is strongly recommended for the patients, for better controlling this progressive deterioration disorder.

Opposing effects of pigment epithelium-derived factor on breast cancer cell versus neuronal survival: implication for brain metastasis and metastasis-induced brain damage.

Brain metastases are a significant cause of morbidity and mortality for patients with cancer, yet preventative and therapeutic options remain an unmet need. The cytokine pigment epithelium-derived factor (PEDF) is downregulated in resected human brain metastases of breast cancer compared with primary breast tumors, suggesting that restoring its expression might limit metastatic spread. Here, we show that outgrowth of large experimental brain metastases from human 231-BR or murine 4T1-BR breast cancer cells was suppressed by PEDF expression, as supported by in vitro analyses as well as direct intracranial implantation. Notably, the suppressive effects of PEDF were not only rapid but independent of the effects of this factor on angiogenesis. Paralleling its cytotoxic effects on breast cancer cells, PEDF also exerted a prosurvival effect on neurons that shielded the brain from tumor-induced damage, as indicated by a relative 3.5-fold reduction in the number of dying neurons adjacent to tumors expressing PEDF. Our findings establish PEDF as both a metastatic suppressor and a neuroprotectant in the brain, highlighting its role as a double agent in limiting brain metastasis and its local consequences.

Rodent Glioma Models: Intracranial Stereotactic Allografts and Xenografts.

Modeling human disease in small animals has been fundamental in advancing our scientific knowledge and for the development of novel therapeutic strategies. In the case of brain cancer, implantable tumor models, both intracranial and also in the periphery, have been widely used and extensively characterized. These models can be used to better understand certain aspects of tumor biology such as growth, neovascularization, response to potential therapies, and interaction with the immune system. Brain tumors from patients as well as rodents have been cultured in vitro, in an attempt to establish permanent cell lines. Human glioma tumors have also been maintained by serial passage in the flanks of immune-deficient animals, as it has been shown that it is not feasible to continuously passage them in culture. In this chapter, we describe various gliomas that have been isolated from mice, rats, and humans and subsequently used as syngeneic or xenograft tumor models in vivo. The majority of the models that we present in this chapter arose either spontaneously or by administration of chemical carcinogens. We compare and contrast the histopathological, genetic, and invasive features of the tumor lines as well as identify novel treatment modalities that have been developed. Finally, we present the procedures for intracranial implantation of tumor cells in rodents using stereotactic surgical techniques. The use of this technique enables the generation of large numbers of animals harboring intracranial tumors with relative ease and the survival of tumor-bearing animals is highly reproducible. These characteristics make the use of these in vivo models very attractive when aiming to develop and test the effectiveness of novel anticancer therapies.

Stent-Assisted Coiling of Intracranial Bifurcation Aneurysms Leads to Immediate and Delayed Intracranial Vascular Angle Remodeling

Wide-neck bifurcating aneurysms are increasingly treated with intracranial stent-assisted coiling by using shape-memory alloy microstents. We sought to investigate the short- and long-term effects of intracranial stent implantation on the geometry and angular conformation of the stent-coiled vascular bifurcation. Thirty patients underwent stent-mediated coiling for 31 bifurcation aneurysms by using 31 self-expanding Neuroform (n = 14) and Enterprise (n = 17) stents (17 women; mean age, 56 years). The angle (δ) between the stented mother and daughter vessels at the bifurcation was measured by using multiplanar imaging of reconstructed rotational conventional angiography volumes and was compared by using matched-pair statistics. Neuroform and Enterprise longitudinal stent stiffness was measured in vitro at an increasing bending angle θ (θ = 180°-δ). Stent deployment increased the bifurcation angle δ from 101.5° to 119.8° postprocedurally and to 137.3° (P < .0001) at latest follow-up, resulting in effective straightening; the angular remodeling was greater in distal-versus-proximal arteries (anterior cerebral > MCA > BA > ICA), inversely proportional to mother-vessel diameter and proportional to pretreatment bending angle θ. At follow-up, angle δ continued to significantly expand, with remodeling being greater in the early period (1-6 versus >7 months) and more pronounced with the longitudinally stiffer closed-cell Enterprise compared with the open-cell Neuroform stent. Stent placement across bifurcation aneurysms leads to a significant biphasic angular remodeling related to stent type and vessel caliber, altering morphology to mimic sidewall lesions, a phenomenon needing consideration during procedural planning. Future work is needed to uncover the hemodynamic implications of this structural change and any possible effect on aneurysm-recurrence rates.

Genomic and Molecular Properties of Relapsed CNS Lymphoma Using Novel Primary Meningeal Lymphoma Cell Lines and Intracranial Xenografts,

Abstract 3477 Background:There is a paucity of molecular information regarding the phenotype of relapsed aggressive CNS lymphoma, a condition for which there are few effective treatment options and, as a consequence, patient survival is often short. To test our hypothesis that the molecular properties of CNS lymphoma at relapse are distinct from those at diagnosis we pursued two parallel lines of investigation: 1) the genomic analysis of relapsed aggressive CNS lymphomas in comparison to newly diagnosed specimens and 2) the generation of novel CNS lymphoma cell lines derived from recurrent meningeal lymphomas isolated from the cerebrospinal fluid. We hypothesize that this approach will facilitate the identification of the underlying molecular determinants of tumour progression, novel genome-based biomarkers and therapeutic targets. Methods:We compared genome copy number using high-resolution array comparative genomic hybridization (array-CGH) and used bioinformatics to study a carefully selected cohort of tumours comprised of 10 newly-diagnosed primary CNS lymphomas (large B-cell) and 7 relapsed/refractory CNS lymphomas (5 large B-cell, 2 of transformed histology). We evaluated copy number aberrations that occurred in the tumour cohort as a whole as well as those that occur predominantly in relapsed cases. In addition, we established five novel lymphoma cell lines from relapsed cases, three of which were derived from meningeal lymphomas isolated from the cerebrospinal fluid and expanded upon intracranial implantation in NSG mice as patient-derived xenografts. Results:There was a trend for an increase in the proportion of copy number losses involving the short arm of chromosome 6 as well as overall gains on chromosome 12 among the relapsed cases. Significant DNA copy number gains for STAT6 were noted in 4/7 relapsed cases. We observed a significant number of deletions present in between 50–90% of newly diagnosed tumors that were absent in CNS lymphomas at relapse, suggestive of complex genomic remodeling during tumour evolution. In addition, a region with potential prognostic implications was identified at chromosome 19p.13.3 that was deleted in 57% of relapsed tumors but not in newly diagnosed cases. Three of the five relapsed large cell cases exhibited significant deletions, including one focal homozygous deletion, at chromosome 4q23.3–4q23.5, a region not previously shown to be deleted in large cell lymphoma (Lenz et al., PNAS, 2008). Both chromosomes 14 and 22 have copy number aberrations that occur in > 80% of all tumours as well as high frequency focal aberrations that appear linked to either good or poor prognosis. Significantly, the MTAP and CDKN2A genes at 9q21 are homozygously co-deleted in 18% of poor prognosis or relapsed patients.Notably, each of the orthotopic xenografts exhibited an ABC immunophenotype and were diffusely infiltrative with meningeal tropism. In fact, CNS metastasis to the meninges was recapitulated when the lymphoma cells were implanted in flank and spontaneously metastasized to brain, within three months post injection. In vitro chemotaxis assays demonstrated responsiveness of human meningeal lymphoma cells to CXCL-13 and SDF-1, chemokines postulated to contribute to the CNS tropism of NHL. Importantly, genomic aberrations identified in the parent tumours were retained when the relapsed meningeal lymphomas were serially passaged by intracranial implantation as xenografts, as evidenced by array-CGH. Conclusions:We believe that this study represents the first analysis of the biologic and genetic properties of relapsed CNS lymphoma. This analysis provides the first direct evidence that chemokines previously shown to be expressed in the CNS lymphoma microenvironment direct chemotaxis of meningeal lymphoma cells isolated from patients. This result is suggestive of a molecular mechanism which may be essential to CNS tropism. In addition, we have established the first in vivo model system of CNS lymphoma which retains the genomic properties of relapsed, refractory disease and which has significant potential for preclinical testing of novel therapeutic strategies.Supported by Leukemia and Lymphoma Society and NIH Grant CA13908301. Disclosures:No relevant conflicts of interest to declare.

Exclusion of giant aneurysm of cavernous part of internal carotid artery by intracranial implantation of stream-directive stent Silk

The case of endovascular surgical treatment of giant aneurysm of cavernous part of internal carotid artery by stream-directive stent Silk implantation as an example of new advanced technology for brain giant aneurysms’ treatment is given. The results of control investigation 3 months after operation showed high efficacy of applied endovascular technology and satisfactory result of surgical treatment. This method requires further research.

Intracranial depth electrodes implantation in the era of image-guided surgery

The advent of modern image-guided surgery has revolutionized depth electrode implantation techniques. Stereoelectroencephalography (SEEG), introduced by Talairach in the 1950s, is an invasive method for three-dimensional analysis on the epileptogenic zone based on the technique of intracranial implantation of depth electrodes. The aim of this article is to discuss the principles of SEEG and their evolution from the Talairach era to the image-guided surgery of today, along with future prospects. Although the general principles of SEEG have remained intact over the years, the implantation of depth electrodes, i.e. the surgical technique that enables this method, has undergone tremendous evolution over the last three decades, due the advent of modern imaging techniques, computer systems and new stereotactic techniques. The use of robotic systems, the constant evolution of imaging and computing techniques and the use of depth electrodes together with microdialysis probes will open up enormous prospects for applying depth electrodes and SEEG both for investigative use and for therapeutic use. Brain stimulation of deep targets and the construction of "smart" electrodes may, in the near future, increase the need to use this method.

Interictal magnetoencephalographic findings related with surgical outcomes in lesional and nonlesional neocortical epilepsy

Purpose To investigate whether interictal magnetoencephalography (MEG) concordant with other techniques can predict surgical outcome in patients with lesional and nonlesional refractory neocortical epilepsy (NE). Methods 23 Patients with lesional NE and 20 patients with nonlesional NE were studied. MEG was recorded for all patients with a 275 channel whole-head system. Synthetic aperture magnetometry (SAM) with excess kurtosis (g2) and conventional Equivalent Current Dipole (ECD) were used for MEG data analysis. 27 Patients underwent long-term extraoperative intracranial video electroencephalography (iVEEG) monitoring. Surgical outcomes were assessed based on more than 1-year of post-surgical follow-up using Engel classification system. Results As we expected, both favorable outcomes (Engel class I or II) and seizure freedom outcomes (Engel class IA) were higher for the concordance condition (MEG findings are concordant with MRI or iVEEG findings) versus the discordance condition. Also the seizure free rate was significantly higher ( χ 2 = 5.24, P < 0.05) for the patients with lesional NE than for the patients with nonlesional NE. In 30% of the patients with nonlesional NE, the MEG findings proved to be valuable for intracranial electrode implantation. Conclusions This study demonstrates that a favorable post-surgical outcome can be obtained in most patients with concordant MEG and MRI results even without extraoperative iVEEG monitoring, which indicates that the concordance among different modalities could indicate a likelihood of better postsurgical outcomes. However, extraoperative iVEEG monitoring remains prerequisite to the patients with discordant MEG and MRI findings. For nonlesional cases, our results showed that MEG could provide critical information in the placement of intracranial electrodes.

Metabolic Targeting of Lactate Efflux by Malignant Glioma Inhibits Invasiveness and Induces Necrosis: An In Vivo Study

Glioblastoma multiforme (GBM) are the most malignant among brain tumors. They are frequently refractory to chemotherapy and radiotherapy with mean patient survival of approximately 6 months, despite surgical intervention. The highly glycolytic nature of glioblastomas describes their propensity to metabolize glucose to lactic acid at an elevated rate. To survive, GBMs efflux lactic acid to the tumor microenvironment through transmembrane transporters denoted monocarboxylate transporters (MCTs). We hypothesized that inhibition of MCT function would impair the glycolytic metabolism and affect both glioma invasiveness and survival. We examined the effect on invasiveness with α-cyano-4-hydroxy-cinnamic acid (ACCA, 4CIN, CHCA), a small-molecule inhibitor of lactate transport, through Matrigel-based and organotypic (brain) slice culture invasive assays using U87-MG and U251-MG glioma cells. We then conducted studies in immunodeficient rats by stereotaxic intracranial implantation of the glioma cells followed by programmed orthotopic application of ACCA through osmotic pumps. Effect on the implanted tumor was monitored by small-animal magnetic resonance imaging. Our assays indicated that glioma invasion was markedly impaired when lactate efflux was inhibited. Convection-enhanced delivery of inhibitor to the tumor bed caused tumor necrosis, with 50% of the animals surviving beyond the experimental end points (3 months after inhibitor exhaustion). Most importantly, control animals did not display any adverse neurologic effects during orthotopic administration of ACCA to brain through programmed delivery. These results indicate the clinical potential of targeting lactate efflux in glioma through delivery of small-molecule inhibitors of MCTs either to the tumor bed or to the postsurgical resection cavity.

Detection of early response to temozolomide treatment in brain tumors using hyperpolarized 13C MR metabolic imaging.

To demonstrate the feasibility of using DNP hyperpolarized [1-(13)C]-pyruvate to measure early response to temozolomide (TMZ) therapy using an orthotopic human glioblastoma xenograft model. Twenty athymic rats with intracranial implantation of human glioblastoma cells were divided into two groups: one group received an oral administration of 100 mg/kg TMZ (n = 10) and the control group received vehicle only (n = 10). (13)C 3D magnetic resonance spectroscopic imaging (MRSI) data were acquired following injection of 2.5 mL (100 mM) hyperpolarized [1-(13)C]-pyruvate using a 3T scanner prior to treatment (day D0), at D1 (days from treatment) or D2. Tumor metabolism as assessed by the ratio of lactate to pyruvate (Lac/Pyr) was significantly altered at D1 for the TMZ-treated group but tumor volume did not show a reduction until D5 to D7. The percent change in Lac/Pyr from baseline was statistically different between the two groups at D1 and D2 (P < 0.008), while percent tumor volume was not (P > 0.2). The results from this study suggest that metabolic imaging with hyperpolarized [1-(13)C]-pyruvate may provide a unique tool that clinical neuro-oncologists can use in the future to monitor tumor response to therapy for patients with brain tumors.

Abstract 624: Efficacy of KetoCal as an adjuvant therapy for malignant gliomas

Abstract The ketogenic diet (KD) is a high-fat, low-carbohydrate diet that alters the body's metabolism to burn fats in preference to carbohydrates. The use of fats as a primary energy source leads to a state of ketosis and the accumulation of ketone bodies in the blood. KetoCal (Nutricia North America, Gaithersburg, MD) is a nutritionally complete, commercially available 4:1 (fat: carbohydrate + protein) ketogenic formula that is an effective non-pharmacologic treatment for the management of pediatric epilepsy. Diet-induced changes to brain homeostasis as a result of ketosis have shown potential as an alternative treatment for other neurological diseases including malignant gliomas. We previously showed that Bio-Serv F3666 (Frenchtown, NJ), a rodent KD with a fat to carbohydrate + protein ratio of 6:1, potentiates the activity of both radiation and temozolomide (TMZ) therapy. We studied the efficacy of KetoCal as an adjuvant treatment for malignant glioma in combination with radiation or TMZ. GL261-luc cells expressing luciferase were stereotactically implanted into the right frontal lobe of albino C57BL/6 mice (NCI, Frederick, MD). Following intracranial implantation, animals were fed standard rodent chow (SD) and were randomized to treatment groups on day 3 (SD vs KetoCal with and without radiation or TMZ) based on bioluminescent signal (IVIS® Spectrum, Caliper Life Sciences, Hopkinton, MA). Blood levels of β-hydroxybutyrate (βHB) and glucose were measured using a Keto-Site reflectance meter (GDS Technologies, Elkhart, IN) and HemoCue Glucose System (HemoCue AB, Ängelholm, Sweden). βHB and glucose levels were checked one and two weeks following the initiation of diet treatment. Mice were maintained on a 12 hour light/dark cycle and KetoCal or SD was available ad libitum. Animals fed KetoCal had elevated levels of βHB (p=0.0173), decreased levels of glucose (p=0.0224) and increased median survival of approximately 6 days relative to animals on SD. To determine if KetoCal enhanced the effect of radiation; mice received 2 × 4 Gy whole brain radiation in combination with SD or KetoCal. Irradiated animals fed SD had a median survival of 44.5 days, while irradiated animals maintained on KetoCal demonstrated a complete loss of bioluminescence, suggesting the absence of viable tumor cells. These animals have been followed for &amp;gt;170 days with no visible signs of recurrent tumor (p=0.0061). Animals fed KetoCal in combination with TMZ (5×50mg/kg) had a median survival of 37 days compared to 28 days for animals treated with TMZ and maintained on SD (p=0.0043). In summary, the 4:1 fat: carbohydrate + protein ratio in KetoCal appears to provide a higher anti-tumor effect than a 6:1 formulation when used in addition to radiation or TMZ. The effect is particularly pronounced when used in combination with radiation. This suggests that cellular metabolic alterations brought about through changes in the diet may be useful for the treatment of human malignant gliomas. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 624. doi:10.1158/1538-7445.AM2011-624

Abstract 5397: Human mesenchymal stem cell-based cell carrier for tumor-homing delivery of replicating retrovirus vectors in glioblastoma models

Abstract In previous studies, we have demonstrated that replicating murine leukemia virus (RMLV)-based vectors can achieve highly efficient in vivo delivery of prodrug activating genes in glioblastoma models, with infection restricted to actively dividing tumor cells without spread to extratumoral sites, resulting in significantly prolonged survival upon prodrug administration; this approach is now being tested in a multi-center clinical trial. RMLV vectors can eventually spread to almost all actively dividing GBM cells over time. We are seeking to further improve the efficiency of this novel therapeutic strategy by engineering human mesenchymal stem cells (MSC) to function as RMLV vector producer cells (MSC-VPC). Primary MSC have been shown to actively migrate through tumor masses beyond the immediate injection site and track to diffusely infiltrating tumor foci. In the present study, we developed optimized methods for engineering MSC-VPC, and we then further examined tumor transduction efficiency of MSC-mediated RMLV delivery, and how this delivery method might affect vector replication kinetics in vivo. First, we evaluated the vector productivity of MSC-VPC in U87 human glioblastoma cells in vitro. Primary human MSCs were infected with RMLV vector AC3-GFP, expressing the GFP marker gene. These MSC were then re-plated at very low density onto a monolayer of naïve U87 glioma cells, and fluorescence was monitored over time. Under the fluorescent microscope, progressive spread of the RMLV vector released from the MSCs could be confirmed, as indicated by increasing GFP(+) U87 cells over time. Next, we tested MSC-VPC in intracranial U87 tumor models in vivo. Five days after intracranial tumor cell implantation, 1E3 transduction units (TU) of AC3-GFP vector or 5E3 MSC-VPC (∼20% pretransduced with AC3-GFP) were stereotactically injected at the tumor site. Tumors were harvested and digested on day 9 for FACS analysis to detect GFP expression. While the highest percentage of GFP(+) cells was 28.6% in the vector supernatant-treated group, up to 45% transduction efficiency was achieved in the MSC-VPC group. These results suggest the use of MSCs as tumor-homing carriers may be provide more efficient delivery of RMLV vectors in human glioma models. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5397. doi:10.1158/1538-7445.AM2011-5397

Abstract 2846: Pigment epithelium-derived factor (PEDF) functions as a brain metastasis suppressor of breast cancer

Abstract Brain metastases occur in 10-20% of metastatic breast cancer patients. The one year survival rate is approximately 20%. Brain metastasis is typically diagnosed late in breast cancer progression; however, studies suggest that the incidence of brain metastasis may be increasing under current chemotherapeutic regimens. We have investigated changes in gene expression associated with the acquisition of brain metastatic potential by breast cancer. A DNA microarray analysis comparing human brain metastases and a cohort of unlinked primary breast carcinomas identified Pigment Epithelium-Derived Factor (PEDF) as down-regulated in the brain metastases relative to the primary tumors (mean ∼14X lower by QPCR validation). The data suggest the hypothesis that PEDF may have a negative impact on brain metastatic progression. PEDF, a secreted factor, has been shown to act as a tumor suppressor, has strong anti-angiogenic activity, but supports the proliferation/viability/ differentiation of neural tissue. We hypothesize that the multiple roles of PEDF make it a potent agent which targets not only tumor cells, but also the microenvironment of the brain. In vitro experiments demonstrated that PEDF can promote death of breast cancer cells. Conversely, PEDF promoted neuronal survival, in vitro. In a xenograft model system (231BR, a brain-tropic derivative of human MDA-MB-231 breast cancer cells) PEDF overexpression inhibited formation of large brain metastases (∼2-fold, p=0.001) and reduced proliferation of PEDF-expressing breast cancer cells in mouse brain metastases (11% Ki67-positive, PEDF-positive vs. &amp;gt;56% Ki67-positive, PEDF-negative). In an intracranial implantation model, expression of PEDF by breast cancer cells lead to a rapid reduction in brain metastatic tumor volume. Histological examination suggests that PEDF reduces gliosis and protects neurons concomitant to suppression of metastatic growth. The data suggest the intriguing possibility that PEDF overexpression may concurrently inhibit brain metastasis of breast cancer cells but preserve neuronal function. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2846. doi:10.1158/1538-7445.AM2011-2846

Abstract 5304: A genetically engineered mouse model for GBM wherein Akt kinase activity can be monitored non-invasively in real-time

Abstract Approximately 30-40% of human gliomas exhibit mutations in the tumor suppressor gene PTEN resulting in deregulation of the phosphoinositide 3-kinase/Akt survival signaling pathway. In a significant number of GBMs tumor initiation is additionally driven by an oncogenic signal stemming from the gene locus amplification of the Platelet derived growth factor receptor (PDGFR), also leading to Akt and mammalian target of rapamycin (mTOR) activation. Phosphorylated, active Akt controls a plethora of cellular responses by regulating a large number of substrates, such as GSK-3, BAD, Forkhead transcription factors (FOXO), and MDM2. Elevated Akt activity increases tumor cell growth, survival and impairs apoptosis. Thus blocking Akt phosphorylation to treat cancer in particular gliomas has therapeutic potential. Here we demonstrate the pre-clinical use of a bioluminescent molecular reporter to evaluate Akt kinase inhibition in real time in a genetically engineered PDGF-driven PTEN-deficient mouse model of GBM. Glial cell specific delivery of the bioluminescent reporter was achieved by RCAS-TVA technology. In brief, we utilized genetically engineered PTEN loxP/loxP, Ink4a-Arf -/-, nestin-TVA transgenic animals and delivered the Akt reporter along with Cre recombinase and PDGF by intracranial implantation of chicken cells expressing avian virus containing the specific cargo. PTEN deletion in nestin positive cells resulted in increased Akt kinase phosphorylation as demonstrated by western blotting. Tumor growth was monitored by MRI and Bioluminescence imaging (BLI) technology. The design of the previously described Akt reporter allows for detectable bioluminescence only in the absence of Akt kinase activity due to the reconstitution of the wt luciferase enzyme. To evaluate the therapeutic potential of PI3-kinase- and Akt inhibitors in this pre-clinical GBM model, tumors were treated with either perifosine or API-2. Increased bioluminescence activity was observed in gliomas in a time- and dose-dependent manner with both inhibitors. These findings demonstrate that the Akt reporter provided a quantitative surrogate for Akt activity in PTEN-deficient gliomas. In conclusion we have provided a novel approach of pairing molecular imaging with a murine GBM model to investigate targeted agents. This may aid the future identification of most efficacious drug combinations impinging on PI3-kinase/Akt signaling in gliomas. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5304. doi:10.1158/1538-7445.AM2011-5304

Epilepsy surgery in Argentina: Long-term results in a comprehensive epilepsy centre

Rationale Epilepsy surgery procedures started in Argentina more than 50 years ago. This is the first comprehensive and systematic survey of epilepsy surgery long-term outcome from our country. Methods A descriptive cohort study was conducted between 1998 and 2008 for drug-resistant epilepsy surgery with a minimum of 12 months follow-up ( n = 110). In 84 cases (76.36%) resective surgery was performed, and outcome periodically assessed using the Engel score. Patients were stratified into groups: 12, 13–36, 37–60 and over than 60 months of follow-up. Video-EEG with and without intracranial electrode implants, intraoperative electrocorticograms, Wada tests, pathology reports, use of antiepileptic drugs (AEDs), and surgical complication rates were evaluated. Results Surgical techniques included: 69 lobectomies (62.7%), 15 lesionectomies (13.6%), 6 callosotomies (5.4%), 6 multiple subpial transection (5.4%), 11 vagus nerve stimulations (10%), 3 hemispherectomies (2.7%). Male: female ratio: 1/1.44. Mean age at time of surgery: 26.2 years. Mean duration of epilepsy: 14 years. Age at seizure onset: 11.5 years. Mean follow-up: 46 months. Pathology findings: mesial temporal sclerosis 32 (35.1%); dual pathology 17 (18.7%); cortical dysplasia 15 (16.4%); non-specific inflammatory changes 11 (12.1%); tumors 7 (7.7%); other 6 (6.8%). Engel scores at 12 months follow-up: 72.6% (61) class I, 16.6% (14) class II and 15.5% (13) class III–IV; 13–36 months after surgery: 68.1% of cases were class I, 15.9% class II and 15.5% class III–IV. After 37–60 months, 74% class I, 14% class II, 14% class III–IV. Over 60 months ( n = 45) 78% class I, 13.5% class II and 8.1% class III–IV. Conclusion Conducting a successful epilepsy surgery program in a developing country is challenging. These results should encourage specialists in these countries. Long-term outcome results comparable to centres in developed countries can be achieved.

Detection of collagens in brain tumors based on FTIR imaging and chemometrics

Fourier transform infrared (FTIR) imaging has been used as a molecular histopathology tool on brain tissue sections after intracranial implantation and development of glioma tumors. Healthy brain tissue (contralateral lobe) as well as solid and diffuse tumor tissues were compared for their collagen contents. IR spectra were extracted from IR images for determining the secondary structure of protein contents and compared to pure product spectra of collagens (types I, III, IV, V, and VI). Multivariate statistical analyses of variance and correspondence factorial analysis were performed to differentiate healthy and tumor brain tissues as well as their classification according to their secondary structure profiles. Secondary structure profiles revealed that no collagen was present in healthy tissues; they are also significantly different from solid and diffuse tumors (p < 0.05). Solid and diffuse tumors could be discriminated with respect to the secondary structure profile of fibrillar and non-fibrillar collagens, respectively. We can thus propose to develop FTIR imaging for histopathology examination of tumors on the basis of collagen contents.

Clinical significance of ictal high frequency oscillations in medial temporal lobe epilepsy

Objective To clarify the clinical significance of ictal high frequency oscillations (HFO) in the medial temporal lobe. Methods This study included 19 patients who underwent intracranial electrode implantation in bilateral temporal lobes and had at least one seizure recorded at 1 kHz sampling rate. The characteristics of ictal HFO in the medial temporal lobe, and the relations between the presence of HFO, pathology, and postoperative seizure outcome were analyzed. Results Ictal HFO were detected from medial temporal structures in 11 patients with medial temporal lobe epilepsy (MTLE). Among eight patients without HFO, only three were diagnosed with MTLE. Ictal HFO were detected from unilateral medial temporal structures ipsilateral to the side of hippocampal sclerosis (HS). In one patient with bitemporal independent seizure onset, ictal HFO were detected only on the side of HS. HS was detected in all 11 patients with HFO, but in only one of four patients without HFO. Seizure outcome did not differ between patients with and without HFO. Conclusions Ictal HFO in the medial temporal lobe may be a specific marker for MTLE with HS. Significance Recording of ictal HFO in the medial temporal lobe may be useful for presurgical evaluation of MTLE.

Lead Cap Localization using Ultrasound in Deep Brain Stimulation Surgery: Technical Note

In deep brain stimulation (DBS) surgery, after intracranial lead implantation, lead caps are tunneled into the subgaleal space for later connection to internal pulse generator (IPG) extension wires. In the subsequent IPG implantation procedure, the lead cap must be localized by palpation in order to plan an incision in the scalp to complete this connection. However, if the IPG implantation is done the same day as the intracranial lead implantation, palpation of the lead cap may be challenging in a thick or postoperatively edematous scalp. Manufacturers suggest using fluoroscopy in these instances, but fluoroscopy provides poor soft tissue visualization, requires further unnecessary radiation exposure to both the patient and the surgical team, and can be cumbersome. Portable ultrasound (US) machines are readily available in many operating rooms, and can be used to easily and accurately localize the lead cap prior to IPG implantation.

Merging Tradition with Innovation: Intraoperative Corticography and 7 Tesla Magnetic Resonance Imaging Sparing Chronic Intracranial Electrode Implantation in "Non-Lesional" Epilepsy Surgery

Merging Tradition with Innovation: Intraoperative Corticography and 7 Tesla Magnetic Resonance Imaging Sparing Chronic Intracranial Electrode Implantation in "Non-Lesional" Epilepsy Surgery

Intrinsic functional architecture predicts electrically evoked responses in the human brain

Intrinsic functional architecture predicts electrically evoked responses in the human brain