Surgical treatment of a basilar perforator aneurysm not accessible to endovascular treatment

Aneurysms originating from perforatoring branches of the midbasilar artery are extremely rare. Rupture of such an aneurysm resulted in a subarachnoid hemorrhage with a prepontine clot in a 44 year old male who presented with an acute confusional state. After coil embolization had failed, the partially thrombosed aneurysm was wrapped and coagulated via a combined supra-/infratentorial subtemporal presigmoid approach in prone position. The postoperative course was complicated by a tension pneumatocephalus and liquorrhea. Additional aneurysms of the anterior communicating artery and right middle cerebral artery were clipped several months later. The patient recovered well, and except for slight gait ataxia no other deficit remained.

Neural stem cell migration toward gliomas in vitro

Various in vivo studies demonstrated a migration tendency of neural stem cells (NSCs) toward gliomas, making these cells a potential carrier for delivery of therapeutic genes to disseminated glioma cells. We analyzed which factors determine NSC migration and invasion in vitro. Conditioned media prepared from 10 different human glioma cell lines, as well as 13 different tumor-associated growth factors, were analyzed for their chemotactic effects on murine C17.2 NSCs. The growth factor receptor status was analyzed by reverse transcriptase-polymerase chain reaction. Invasion of NSCs into multicellular tumor spheroids generated from 10 glioma cell lines was quantified. NSCs displayed a heterogeneous migration pattern toward glioma spheroids as well as toward glioma-cell-conditioned medium. Chemotactic migration was stimulated up to fivefold by conditioned medium as compared to controls. In coculture assays, NSC invasion varied from single cell invasion into glioma spheroids to complete dissemination of NSCs into glioma spheroids of different cell lines. Among 13 different growth factors, scatter factor/hepatocyte growth factor (SF/HGF) was the most powerful chemoattractant for NSCs, inducing a 2.5-fold migration stimulation. An antibody against SF/HGF inhibited migratory stimulation induced by conditioned media. NSC migration can be stimulated by various growth factors, similar to glioma cell migration. The extent to which NSCs infiltrate three-dimensional glioma cell aggregates appears to depend on additional factors, which are likely to include cell-to-cell contacts and interaction with extracellular matrix proteins.

[Hypothalamic deep brain stimulation in patients with chronic cluster headaches. Suggestions for patient selection]

Cluster headaches involve a stereotypic symptomatic and belong to the most severe primary pain syndromes. Imaging studies have demonstrated functional and structural changes in the inferior-posterior hypothalamus ipsilateral to the pain. These changes are highly specific to the syndrome, strongly suggesting that this anatomical region is the trigger or generator of the acute attacks and/or determine the duration of the acute pain. These findings have led to the successful therapy of 19 not or difficult to treat patients with hypothalamic deep brain stimulation, resulting in long-term periods without pain and without significant side effects. Recently, however, a patient was reported who died after the operation due to increased blood pressure leading to the rupture of a previously non-diagnosed aneurysm. This article offers a translated summary of the recently published criteria of an international consensus group, which, in addition to a positive ethics vote, should be fulfilled before such deep brain stimulation of the hypothalamus is carried out in such patients.

Inhibition of glioblastoma angiogenesis and invasion by combined treatments directed against vascular endothelial growth factor receptor-2, epidermal growth factor receptor, and vascular endothelial-cadherin

PURPOSE

Inhibition of angiogenesis can influence tumor cell invasion and metastasis. We previously showed that blockade of vascular endothelial growth factor receptor-2 (VEGFR-2) with the monoclonal antibody DC101 inhibited intracerebral glioblastoma growth but caused increased tumor cell invasion along the preexistent vasculature. In the present study, we attempted to inhibit glioma cell invasion using a monoclonal antibody against the epidermal growth factor receptor (EGFR), which in the context of human glioblastomas, has been implicated in tumor cell invasion. In addition, we analyzed whether blockade of vascular endothelial (VE)-cadherin as a different antiangiogenic target could also inhibit glioblastoma angiogenesis and growth.

EXPERIMENTAL DESIGNS

Nude mice who received intracerebral glioblastoma xenografts were treated using monoclonal antibodies against VEGFR-2 (DC101), EGFR (C225), and VE-cadherin (E4G10) either alone or in different combinations.

RESULTS

Increased tumor cell invasion provoked by DC101 monotherapy was inhibited by 50% to 66% by combined treatment with C225 and DC101. C225 inhibited glioblastoma cell migration in vitro, but had no effect on the volume of the main tumor mass or on tumor cell proliferation or apoptosis in vivo, either alone or in combination with DC101. The anti-VE-cadherin monoclonal antibody E4G10 was a weaker inhibitor of tumor angiogenesis and growth than DC101, and also caused a weaker increase in tumor cell invasion.

CONCLUSIONS

Inhibition of angiogenesis achieved by blocking either VEGFR-2 or VE-cadherin can cause increased glioma cell invasion in an orthotopic model. Increased tumor cell invasion induced by potent inhibition of angiogenesis with DC101 could be inhibited by simultaneous blockade of EGFR.

Hollow mandrin facilitates external ventricular drainage placement

BACKGROUND

Placement of ventricular catheters is a routine procedure in neurosurgery. Ventricle puncture is done using a flexible ventricular catheter stabilised by a solid steel mandrin in order to improve stability during brain penetration. A correct catheter placement is confirmed after removing the solid steel mandrin by observation of cerebrospinal fluid (CSF) flow out of the flexible catheter. Incorrect placement makes further punctures necessary. The newly developed device allows CSF flow observation during the puncture procedure and in addition precise intracranial pressure (ICP) measurement.

METHOD

The developed mandrin is hollow with a blunt tip. On one side 4-5 small holes with a diameter of 0.8 mm are drilled corresponding exactly with the holes in the ventricular catheter, allowing CSF to pass into the hollow mandrin as soon as the ventricle is reached. By connecting a small translucent tube at the distal portion of the hollow mandrin ICP can be measured without loss of CSF. The system has been used in 15 patients with subarachnoid haemorrhage (SAH) or intraventricular haemeorrhage (IVH) and subsequent hydrocephalus.

FINDINGS

The new system improved the external ventricular drainage implantation procedure. In all 15 patients catheter placement was correct. ICP measurement was easy to perform immediately at ventricle puncture. In 4 patients at puncture no spontaneous CSF flow was observed, therefore by connecting a syringe and gentle aspiration of CSF correct placement was confirmed in this unexpected low pressure hydrocephalus. Otherwise by using the conventional technique further punctures would have been necessary.

CONCLUSIONS

Advantages of the new technique are less puncture procedures with a lower risk of damage to neural structures and reduced risk of intracranial haemorrhages. Implantation of the ventricular catheter to far into the brain can be monitored and this complication can be overcome. Using the connected pressure monitoring tube an exact measurement of the opening intracranial pressure can be obtained performed without losing CSF.

November 2004: intradural mass of the cauda equina in a woman in her early 60s

November 2004. A 63-year-old woman presented with slowly aggravating lower back pain and recent urinary urge incontinence. MRI revealed a sharply-delineated, partly cystic intradural mass with inhomogenous contrast-enhancement and ectatic vessels at the upper pole. An ependymoma was suspected, and the tumor was resected in toto. Histologically, at first glance, the tumor strongly resembled an ependymoma, showing a monomorphic cellular pattern, perivascular pseudorosettes and ependymal canal-like structures. However, the finding of a delicate collagen capsule, compartmentation of tumor cells into zellballen and the presence of ganglionic cells were untypical. These features were indicative of a paraganglioma with a gangliocytic component. Immunoreactivity of the tumor cells for neuroendocrine antigens, the detection of GFAP-positive sustentacular cells and the ultrastructural confirmation of neurosecretory granules substantiated this diagnosis. The clinical, radiological and morphological similarity between ependymomas, which are far more common in the cauda equina region than paragangliomas, has led to substantial diagnostic confusion in the past.

Intraoperative sonography of intra- and extramedullary tumors

Intraoperative ultrasound (IOUS) was used in planning the operative resection of intradural spinal tumors, to define its diagnostic potential and limitations. Since 1997, 78 patients diagnosed with an ependymoma (n = 24), astrocytoma (n = 7), hemangioblastoma (n = 7), neurinoma (n = 15), meningioma (n = 17) and filum terminale ependymoma (n = 8) were examined using intraoperative transdural sonography. Intramedullary tumors turned out to show a heterogeneous image with occasional cystic alterations and an indistinct demarcation to the myelon of comparable echogenicity. Intramedullary tumors are easily distinguishable from their extramedullary counterparts, which display a homogeneous signal intensity and sharp demarcation on IOUS. In conclusion, IOUS allows a reliable diagnosis of intraspinal tumors, allowing the distinction between intra- and extramedullary tumors through their respective signal characteristics. Using IOUS, the extension of the neurosurgical approach can be adopted to the true extent of the tumor; thus, avoiding further bone work while the dura is already opened and the frequently edematous spinal cord protrudes through the opening. Our experiences have shown that IOUS may reduce the procedure-related morbidity and should, therefore, be used as a standard intraoperative tool in these high-risk surgical entities. (E-mail: ).

Einsatz von Vasopressin und Terlipressin bei Sepsis und systemischen Entzündungsreaktionen

Vasopressin and terlipressin are increasingly used as alternative non-adrenergic vasopressors for hemodynamic support of septic patients with arterial hypotension. Despite excellent vasopressive effects, vasopressin analogues may potentially impair macro-hemodynamics, oxygen transport and microvascular blood flow. Due to those unwanted side-effects, vasopressin and terlipressin may potentially compromise organ function and possibly foster the development of multiple organ failure. This review article discusses the results of clinical and experimental studies to judge the effects of vasopressin and terlipressin on microcirculation, oxygen supply, metabolism and organ function in patients with sepsis or systemic inflammatory response syndrome (SIRS). Although vasopressin analogues are emerging as promising alternatives to treat catecholamine-refractory hypotension, there is no evidence that vasopressin receptor agonists improve outcome. To date, vasopressin and terlipressin can, therefore, not be recommended for routine clinical use.

August 2004: 64-year-old man with intermittent paresthesia of the abdomen and of the legs

A 64-year-old-man had a 2-year history beginning with a sense of abdominal "constriction." Additional slowly rising symptoms, such as tingling of the legs, mild gait ataxia and painful micturition, led to MRI investigation of the spinal cord. A fusiform enlargement of the cord extending from T5 to T8 was shown. The space occupying lesion infiltrated diffusely the spinal cord. A contrast medium enhancing exophytic tumor pellet was approached via a 2-level laminoplasty and resected. Biopsies were taken from different exophytic tumor areas whereas the intramedullary part was spared. The histologic examination confirmed the typical pattern of a pilocytic astrocytoma in all specimens. In our surgical experience with 226 intramedullary tumors and with 117 patients affected by intracranial pilocytic astrocytoma this case is unique because of its combination of tumor location, growth pattern and age of the patient.

Well-differentiated neurocytoma: what is the best available treatment?

Most neurocytomas are well differentiated, being associated with better long-term survival than the more aggressive atypical lesions. Atypical neurocytomas are characterized by an MIB-1 labeling index >3% or atypical histologic features. This analysis focuses on well differentiated neurocytomas in order to define the optimal treatment. A case with a follow-up of 132 months is presented. The patient developed two recurrences two and four years after first surgery, each showing an increasing proliferation activity. Furthermore, all published well-differentiated neurocytoma cases were reviewed for surgery, radiotherapy, and prognosis. Additional relevant data were obtained from the authors. Complete resection (CTR), complete resection plus radiotherapy (CTR + RT), incomplete resection (ITR), and incomplete resection plus radiotherapy (ITR + RT) were compared for outcome by using the Kaplan-Meier method and the log-rank test. Data were complete in 301 patients (CTR, 108; CTR + RT, 27; ITR, 81; ITR + RT, 85). Local control and survival were better after CTR than after ITR (P < 0.0001 and P = 0.0085, respectively). Radiotherapy improved local control after ITR (P < 0.0001) and after CTR (P = 0.0474), but not survival (P = 0.17 and P = 1.0, respectively). In the ITR + RT group, doses < or =54 Gy (n = 33) and >54 Gy (n = 32) were not significantly different for local control (P = 0.88) and survival (P = 0.95). The data demonstrated CTR to be superior to ITR for local control and survival. After CTR and ITR, radiotherapy improved local control, but not survival. A radiation dose of 54 Gy appeared sufficient. Application of postoperative radiotherapy should be decided individually, taking into account the risk of local failure, the need for another craniotomy, and potential radiation toxicity.

Receptor protein tyrosine phosphatase ζ as a therapeutic target for glioblastoma therapy

Astrocytomas are the most frequent brain tumour type in adults. The most common astrocytoma is the glioblastoma (GBM), which is also the most malignant and refractory to treatment--ultimately leading to the patient's death within a year of diagnosis. Neither the classical nor more experimental therapeutic approaches have significantly improved the clinical outcome of this disease. Expression profile analysis of primary tumours has provided recent insight into the identification of new GBM therapeutic targets. These proteins serve as excellent candidates to either inhibit the target molecule's functions (e.g., angiogenesis, migration or proliferation) or, coupled with a toxin or radionucleotide, to bind and exterminate the tumour cells. The receptor protein tyrosine phosphatase zeta (RPTPzeta) and one of its main ligands, pleiotropin (Ptn), are overexpressed in GBMs, thus making them potentially very good targets for the development of new immunotherapeutics. This review will summarise recent advances in GBM therapies focusing on RPTPzeta as a target for immunotherapeutics.

Comparative assessment of the functional p53 status in glioma cells

BACKGROUND

p53 is the most frequently mutated gene in human cancers and its functional integrity is an important predictor of treatment response and clinical outcome. The majority of mutations found in different types of cancer cluster within the DNA binding domain encoded by exons 5-8. In clinical specimens the functional status of p53 is, therefore, often evaluated by direct mutation analysis of exons 5-8 or indirectly by immunostaining and evaluation of the subcellular localization pattern or protein accumulation.

MATERIALS AND METHODS

In a panel of glioma cell lines, the status of the P53 gene was analyzed by temperature gradient gel electrophoresis (TGGE) of exons 5-8 and direct sequencing of all p53 exons. The nuclear accumulation of p53 in unstressed cells was assessed by immunostaining. These data were correlated with stress induction of the p53 protein, nuclear translocation and a direct determination of the transcriptional activity of endogenous p53 protein and induction of p53 target genes.

RESULTS

Our analysis demonstrated that a p53 gene mutation analysis limited to exons 5-8 and analysis of immunostaining patterns can not serve as reliable predictors of functional p53 in tumor cells. Conversely, in some presumably rare cases, the transcriptional activity of p53 may be retained in tumor cells in the presence of a mutation and a pathological immunostaining pattern. In our analysis, the constitutive dephosphorylation at Ser 376 correlated with the nuclear accumulation of p53, but not with the transcriptional activity of the protein. This suggests that constitutive dephosphorylation at Ser376 may be one of the factors determining stabilization of mutant and wild-type p53, which is frequently observed in glial tumors.

CONCLUSION

The incidence of a dysfunctional p53 protein in gliomas may be higher than expected, based on a single parameter evaluation by mutation analysis of exons 5-8 or assessment of p53 accumulation and subcellular localization by immunostaining.

New approach to an ovine model of hypodynamic endotoxaemia

BACKGROUND AND OBJECTIVE

Since the moribund hypodynamic phase of septic shock has primarily been studied in small animal models, the objective of this study was to investigate the usefulness of infusing Salmonella typhosa endotoxin at incrementing doses to establish an ovine model of hypodynamic endotoxaemia.

METHODS

In a prospective laboratory experiment, eight adult ewes were instrumented for a chronic study. Following a baseline measurement in the healthy state, a continuous endotoxin infusion was started with 10 ng kg(-1) min(-1) and was doubled every hour seven times. Haemodynamics, key variables of oxygen transport, and arterial lactate concentrations were determined every hour.

RESULTS

In a dose-dependent manner, endotoxin infusion caused pulmonary hypertension, decreased cardiac output and mean arterial pressure, increased heart rate, and to a certain extent, systemic vascular resistance index. Following 4h of endotoxaemia, the maximum decrease in cardiac output occurred (4.8+/-0.2 vs. 7.6+/-0.3 Lmin(-1); P < 0.001). This was accompanied by tissue dysoxia, represented by decreases in oxygen delivery (797+/-20 vs. 1041+/-28 mLmin(-1)), oxygen consumption (277+/-14 vs. 396+/-15 mLmin(-1)) and oxygen extraction rate (0.35+/-0.01 vs. 0.38+/-0.01%; each P < 0.01), as well as an increase in arterial lactate concentration (1.7+/-0.1 vs. 0.7+/-0.1 mmolL(-1); P < 0.05).

CONCLUSIONS

This large animal model may be helpful to study the pathophysiology responsible for cardiovascular failure, and also new therapeutic approaches relevant to management of hypodynamic circulation in the common setting of progressed systemic inflammation.

Perspectives of Cellular and Molecular Neurosurgery

Therapeutic efforts for human glial tumors have over the past years been redirected towards a compartmental treatment concept. The diffusely infiltrative nature of the disease calls for therapeutic agents to reach single cells far beyond the focus of attention which present therapies like surgery and radiation are able to treat. Specific drug discovery approaches which seek to define targets which are specific for gliomas have generated therapeutic options which allow for a highly selective development of new reagents. Combined with new modalities for compartmental drug delivery, systemic complications might be reduced and advantage taken of a compartmental specificity of a target which otherwise in the context of systemic application would not be as specific or burdened with side effects. From the present status of therapeutic developments in neuro-oncology it can be expected that a sufficient number of drug targets emerge which can be exploited by means of interstitial or intracavitary delivery, which are not neurotoxic and which may even be imaged in their action with the new metabolic imaging modalities. Convection enhanced delivery, conditionally replicating oncolytic viruses and motile, genetically engineered neural stem cells all seem to fulfill the distribution requirements which an effective therapeutic for gliomas will need to overcome the very limited efficacy which surgery, conventional chemotherapy and radiation have to offer. Whereas the genomics based discovery approaches are not specific for neuro-oncology, the development of delivery strategies is highly specific for the central nervous system, thus creating a unique set of organ and disease specific therapies.

Pattern of recurrence following local chemotherapy with biodegradable carmustine (BCNU) implants in patients with glioblastoma

OBJECTIVE

Recently a randomized placebo-controlled phase III trial of biodegradable polymers containing carmustine has demonstrated a significant survival benefit for patients treated with local chemotherapy. A local chemotherapy applied directly to the resection cavity may act directly on residual tumor cells in adjacent brain possibly leading to a local control of the tumor and increased survival.

METHODS

We have analyzed the pattern of recurrence using serial MRI studies of 24 patients treated with GLIADEL Wafers or placebo wafers following resection of glioblastomas.

RESULTS

Of 24 patients 11 received carmustine wafers and 13 placebo. The age distribution and Karnowsky performance scores of the two populations were not different. However, the median survival (14.7 versus 9.5 months; P = 0.007) and the time to neurological deterioration (12.9 +/- 4.85 vs. 9.4 +/- 2.73 months; P = 0.035) was significantly longer in the treatment group versus the placebo treated control. Preoperative and follow up MRI studies were evaluated in a blinded fashion. Out of 24 patients that entered the analysis 11 showed clearance of all contrast enhancement following resection of glioblastomas. Seventeen tumors progressed locally and 7 showed different patterns of distant failure. Within the carmustine treated group 8 patients showed a local treatment failure with recurrent tumors immediately adjacent to the resection cavity or progression form a residual tumor. Three patients showed a multifocal distant and local pattern of failure after complete or subtotal removal. In no case the local chemotherapy resulted in a distant recurrence only. However, the time to radiographic progression was 165.1 +/- 80.75 days for the GLIADEL Wafer group and 101.9 +/- 43.06 days for the placebo group (P = 0.023).

CONCLUSION

In this subgroup analysis of a phase III trial population both the clinical progression and radiological progression were significantly delayed in patients treated with local chemotherapy, resulting in an increased survival time. Local chemotherapy with carmustine containing wafer implants did not result in an altered pattern of recurrence and did not promote multifocal patterns of recurrence.

Angiogenesis-related growth factors in brain tumors

Numerous growth factors have been implicated in glioma angiogenesis. This chapter focuses on the role of scatter factor/hepatocyte growth factor, fibroblast growth factor, platelet-derived growth factor and transforming growth factor beta. We review the expression pattern of these factors in gliomas, their functional contribution to tumor angiogenesis - also in relation to vascular endothelial growth factor, and the effects resulting from their inhibition or overexpression in gliomas in vivo.

[Intraoperative ultrasound of intra- and extramedullary tumours]

AIM

Spinal tumours can be diagnosed precisely by magnetic resonance imaging (MRI). Planning the surgical procedure of intradural tumours, intraoperative ultrasound (IOUS) has been used to evaluate its diagnostic potential.

METHOD

From 1997 to 9/2002 32 patients with the diagnosis of an ependymoma (n = 9), astrocytoma (n = 5), haemangioblastoma (n = 5), neurinoma (n = 4), meningeoma (n = 4) and filum terminale ependymoma (n = 5) were investigated by intraoperative transdural sonography. The sonographic results were correlated to the preoperative MRI-findings and histopathological work-up.

RESULTS

Intramedullary tumours characteristically present with a heterogenous morphology, sometimes carrying intralesional or perilesional cysts. The tumour margins are frequently poorly defined, and there is a perifocal oedema. Extramedullary tumours frequently display a homogenous signal intensity, well defined tumour margins and the abscence of perifocal oedema. Haemangioblastomas turned out to be a specific sonographic entity among intramedullary tumours, as they most often contain only a cystic part with a small tumour nodule. IOUS influenced the surgical approach as laminotomy has to be extended in 7/32 cases to reach the tips of the tumour.

CONCLUSION

The precision of surgical exposure of intradural spinal lesions can be optimised by IOUS which shows a high correlation with MRI characterizing extra- and intramedullary tumours. Using IOUS, the exact position of the laminectomy/laminotomy can be adapted to the true extent of the tumour, thus avoiding the necessity of further bone work in the case of the frequently oedematous spinal cord protruding through the opening in the dura. Overall, IOUS guidance can help to reduce postoperative morbidity in surgery for all spinal intradural lesions.

Expression and Function of the Receptor Protein Tyrosine Phosphatase ζ and Its Ligand Pleiotrophin in Human Astrocytomas

Using subtractive cloning combined with cDNA array analysis, we previously identified the genes encoding for the protein tyrosine phosphatase zeta/receptor-type protein tyrosine phosphatase beta (PTPzeta/RPTPbeta) and its ligand pleiotrophin (PTN) as overexpressed in human glioblastomas compared to normal brain. Both molecules have been implicated in neuronal migration during central nervous system development, and PTN is known to be involved in tumor growth and angiogenesis. We confirm overexpression of both molecules at the protein level in astrocytic gliomas of different malignancy grades. PTPzeta/RPTPbeta immunoreactivity was associated with increasing malignancy grade and localized predominantly to the tumor cells. PTN immunoreactivity as determined by ELISA and immunohistochemistry analysis was increased in low-grade astrocytomas compared to normal brain. Further increase in malignant gliomas was marginal, and thus no correlation with malignancy grade or microvessel density was present. However, PTN levels were significantly associated with those of fibroblast growth factor-2, suggesting co-regulation of both factors. Functionally, PTN induced weak chemotactic and strong haptotactic migration of glioblastoma and cerebral microvascular endothelial cells. Haptotaxis of glioblastoma cells towards PTN was specifically inhibited by an anti-PTPzeta/RPTPbeta antibody. Our findings suggest that upregulated expression of PTN and PTPzeta/RPTPbeta in human astrocytic tumor cells can create an autocrine loop that is important for glioma cell migration. Although PTN is a secreted growth factor, it appears to exert its mitogenic effects mostly in a matrix-immobilized form, serving as a substrate for migrating tumor cells.

A role for receptor tyrosine phosphataseζ in glioma cell migration

Glioblastomas (GBM) are the most frequent and malignant human brain tumor type. Typically striking in adulthood, tumor progression is rapid, relentless, and ultimately leads to the patient's death within a year of diagnosis. The identification of transcriptionally regulated genes can lead to the discovery of targets for antibody or small-molecule-mediated therapy, as well as diagnostic markers. We prepared cDNA arrays that are specifically enriched for genes expressed in human brain tumors and profiled gene expression patterns in 14 individual tumor samples. Out of 25,000 clones arrayed, greater than 200 genes were found transcriptionally induced in glioblastomas compared to normal human brain tissue including the receptor tyrosine phosphatasezeta (RPTPzeta) and one of its ligands, pleiotrophin (Ptn). We confirmed by Northern blot analysis and immunohistochemistry that RPTPzeta is enriched in tumor samples. Knockdown of RPTPzeta by RNA interference studies established a functional role of RPTPzeta in cell migration. Our results suggest a novel function for RPTPzeta in regulating glioblastoma cell motility and point to the therapeutic utility of RPTPzeta as a target for antibody-mediated therapy of brain tumors.

Inhibition of intracerebral glioblastoma growth by local treatment with the scatter factor/hepatocyte growth factor-antagonist NK4

PURPOSE

Scatter factor/hepatocyte growth factor (SF/HGF) and its tyrosine kinase receptor MET are strongly up-regulated in malignant gliomas. The SF/HGF-MET system contributes to glioma invasion and angiogenesis via autocrine and paracrine mechanisms. We analyzed whether local treatment with NK4, an antagonistic fragment of SF/HGF, could inhibit glioma growth in vivo.

EXPERIMENTAL DESIGN

A guide-screw system was used to implant tumor cells intracerebrally and to perform therapeutic injections. Mice received daily intratumoral injections of NK4 or buffer as of day 1 or 7 after tumor cell injection until day 20. Functional effects of NK4 on glioma and endothelial cells were analyzed in vitro.

RESULTS

Tumor volume was reduced by 61.1% in mice treated with NK4 compared with controls when treatment was initiated on day 1 (P < 0.05) and by 61.4% when treatment was initiated on day 7 (P < 0.001). Intratumoral microvessel density was reduced by 64.9% when treatment started on day 1 and by 36.7% when it started on day 7. The proliferative activity of the tumor cells was reduced by >30% regardless of when NK4-treatment was initiated. The apoptotic fraction of tumor cells was increased 2-fold and 1.5-fold when animals were treated with NK4 as of day 1 or day 7, respectively. In vitro, NK4 inhibited SF/HGF-induced glioblastoma, and endothelial cell migration and proliferation in a dose-dependent fashion.

CONCLUSION

NK4 inhibits glioblastoma growth in vivo, most likely via antimitogenic, antimotogenic, proapoptotic, and antiangiogenic mechanisms. Given the strong up-regulation of SF/HGF and MET in human malignant gliomas, NK4 holds promise as a direct interstitial therapeutic agent for these fatal tumors.

Percutaneous fetoscopic tracheal balloon occlusion in sheep

BACKGROUND

In order to minimize maternal trauma from current techniques for temporary fetoscopic tracheal occlusion, we tried to develop a percutaneous fetoscopic technique in sheep.

METHODS

In nine ewes between 77 and 128 days of gestation, the amniotic cavity was entered percutaneously. Each fetus was positioned and the feasibility of fetal laryngoscopy and percutaneous fetoscopic tracheal balloon occlusion was assessed.

RESULTS

Percutaneous intraamniotic access, fetal positioning, oropharyngeal sheath insertion, and fetoscopic laryngoscopy were achieved in all nine fetal sheep. Following some technical modifications to the working channel of the fetoscope, percutaneous fetoscopic tracheal balloon occlusion was successfully achieved in the last seven sheep.

CONCLUSION

Percutaneous fetoscopic balloon occlusion of the fetal trachea can effectively and safely be achieved in sheep. Because intraamniotic spatial relationships, fetal position, and umbilical cord length are technically less favorable in sheep, our operative techniques might be feasible in humans even if difficult intraamniotic conditions are encountered.

Improved method for the intracerebral engraftment of tumour cells and intratumoural treatment using a guide screw system in mice

BACKGROUND

Orthotopic in vivo models for the experimental treatment of malignant gliomas have become indispensable to evaluate the efficacy of novel therapeutic regimens. Recently, a guide screw system was introduced which is implanted into the cranium of small rodents where it facilitates fast, repeated and exactly reproducible intracerebral injections, avoiding time consuming stereotactic procedures. Here we report our experience with this system, and describe several modifications which we introduced to improve its reliability and to simplify its application.

FINDINGS

The most important modification made was the optimization of the guide screw implantation site, which needs to be adapted to the age of the mice. Other improvements were the fixation of the guide screw to the cranium of the mice using a two component adhesive. This avoids the tendency, when daily intratumoural injections are performed over several weeks, for the screw to loosen, making precise injections impossible. The injection procedure, initially described as a free-hand approach, was improved by mounting the syringe to a Greenberg retractor. This provided additional stability and speeded up the process. Applying this modified technique, we were able to achieve reproducible results with regard to engraftment rate, tumour growth, and intratumoural treatment in immunocompromized mice.

INTERPRETATION

We introduced several major and some minor improvements to make working with the guide screw system more reliable, faster and more comfortable. Daily injections over a period of three weeks using this system are feasible and well tolerated by mice.

Percutaneous fetoscopic patch coverage of experimental lumbosacral full-thickness skin lesions in sheep

BACKGROUND

In order to minimize maternal trauma from open fetal surgery for prenatal coverage of fetal myelomeningoceles in humans, we assessed the feasibility of a percutaneous fetoscopic approach in sheep.

METHODS

In seven ewes between 90 and 100 days of gestation, the amniotic cavity was entered percutaneously. Each fetus was postured and a full-thickness skin lesion was created in the lumbosacral region. Then, the feasibility of covering this lesion with a patch and fetal skin by standard endoscopic suturing techniques (n = 3) or robot assistance (n = 4) was assessed.

RESULTS

Percutaneous fetoscopic patch and skin coverage of the full-thickness skin lesion was achieved in six of the seven fetal sheep. Five fetuses survived gestation and were delivered healthy.

CONCLUSIONS

Percutaneous fetoscopic posturing and patch coverage of lumbosacral full-thickness skin lesions can effectively and safely be achieved in sheep. This approach promises to provide a substantial reduction of maternal trauma from fetal surgery for myelomeningoceles.

Safety, tolerability, and tumor response of IL4-Pseudomonas exotoxin (NBI-3001) in patients with recurrent malignant glioma

PURPOSE

This was an open-label, dose-escalation trial of intratumoral administration of IL-4 Pseudomonas exotoxin (NBI-3001) in patients with recurrent malignant glioma.

PATIENTS AND METHODS

A total of 31 patients with histologically verified supratentorial grades 3 and 4 astrocytoma were studied. Of these, 25 patients were diagnosed with glioblastoma multiforme (GBM) while six were diagnosed with anaplastic astrocytoma. Patients were over 18 years of age and had Karnofsky performance scores > or = 60. Patients were assigned to one of four dose groups in a dose-escalation fashion: 6 microg/ml x 40 ml, 9 microg/ml x 40 ml, 15 microg/ml x 40 ml, or 9 microg/ml x 100 ml of NBI-3001 administered via convection-enhanced delivery intratumorally using stereotactically placed catheters. Patients were followed with serial MRI scans and clinical assessments every four weeks for the first 16 weeks and then every eight weeks until week 26.

RESULTS

No drug-related systemic toxicity, as evident by lack of hematological or serum chemical changes, was apparent in any patients; treatment-related adverse effects were limited to the central nervous system. No deaths were attributable to treatment. Drug-related grade 3 or 4 toxicity was seen in 39% of patients in all dose groups and 22% of patients at the maximum tolerated dose of 6 microg/ml x 40 ml. The overall median survival was 8.2 months with a median survival of 5.8 months for the GBM patients. Six-month survival was 52% and 48%, respectively. Gadolinium-enhanced magnetic resonance imaging of the brain showed areas of decreased signal intensity within the tumor consistent with tumor necrosis following treatment in many patients.

CONCLUSIONS

NBI-3001 appears to have an acceptable safety and toxicity profile when administered intratumorally in patients with recurrent malignant glioma.

Glioblastoma and cerebral microvascular endothelial cell migration in response to tumor-associated growth factors

OBJECTIVE

Glioma cell migration is determined by a complex interplay between soluble motogens and extracellular matrix components. Several growth factors are thought to be involved in glioma cell migration; however, little is known about their motogenic potency relative to one another.

METHODS

Using modified Boyden chamber assays, we compared the chemotactic effects of scatter factor/hepatocyte growth factor (SF/HGF), transforming growth factor (TGF)-alpha, TGF-beta1, TGF-beta2, epidermal growth factor (EGF), fibroblast growth factor (FGF)-1, FGF-2, insulin-like growth factor (IGF)-1, IGF-2, platelet-derived growth factor (PDGF)-AA, PDGF-BB, vascular endothelial growth factor (VEGF), pleiotrophin (PTN), and midkine (MK) in concentrations ranging from 1 pmol/L to 50 nmol/L on three different human glioblastoma cell lines. Checkerboard analyses distinguished between chemotaxis and chemokinesis. We further investigated the motogenic effects on human cerebral microvascular endothelial cells and analyzed receptor expression profiles.

RESULTS

SF/HGF was the most potent chemotactic factor for all three glioblastoma cell lines, inducing up to 33-fold stimulation of migration. TGF-alpha showed the second strongest effect (up to 17-fold stimulation), and FGF-1 was also chemotactic for all three glioblastoma cell lines analyzed (maximal 4-fold effect). EGF, FGF-2, IGF-1, IGF-2, TGF-beta1, and TGF-beta2 were chemotactic for one or two of the cell lines (2- to 4-fold effects), whereas PDGF-AA, PDGF-BB, VEGF, PTN, and MK had no effect. In contrast, the most potent stimulators of cerebral microvascular endothelial cell migration were PDGF-AA (4-fold) and PDGF-BB (6-fold).

CONCLUSION

The expression levels of SF/HGF and TGF-alpha as well as their respective receptors, MET and EGFR, are known to correlate with glioma malignancy grade. The particularly strong motogenic effects of these two growth factors suggest that they could be promising targets for an antimigratory component of glioma therapy, at least in comparison with the 12 other factors that were analyzed.

A phase 3 trial of local chemotherapy with biodegradable carmustine (BCNU) wafers (Gliadel wafers) in patients with primary malignant glioma

A previous placebo-controlled trial has shown that biodegradable 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) wafers (Gliadel wafers) prolong survival in patients with recurrent glioblastoma multiforme. A previously completed phase 3 trial, also placebo controlled, in 32 patients with newly diagnosed malignant glioma also demonstrated a survival benefit in those patients treated with BCNU wafers. Because of the small number of patients in that trial, a larger phase 3 trial was performed to confirm these results. Two hundred forty patients were randomized to receive either BCNU or placebo wafers at the time of primary surgical resection; both groups were treated with external beam radiation postoperatively. The two groups were similar for age, sex, Karnofsky performance status (KPS), and tumor histology. Median survival in the intent-to-treat group was 13.9 months for the BCNU wafer-treated group and 11.6 months for the placebo-treated group (log-rank P -value stratified by country = 0.03), with a 29% reduction in the risk of death in the treatment group. When adjusted for factors affecting survival, the treatment effect remained positive with a risk reduction of 28% ( P = 0.03). Time to decline in KPS and in 10/11 neuroperformance measures was statistically significantly prolonged in the BCNU wafer-treated group ( P </= 0.05). Adverse events were comparable for the 2 groups, except for CSF leak (5% in the BCNU wafer-treated group vs. 0.8% in the placebo-treated group) and intracranial hypertension (9.1% in the BCNU wafer-treated group vs. 1.7% in the placebo group). This study confirms that local chemotherapy with BCNU wafers is well tolerated and offers a survival benefit to patients with newly diagnosed malignant glioma.

Cost of migration: invasion of malignant gliomas and implications for treatment

Tumors of glial origin consist of a core mass and a penumbra of invasive, single cells, decreasing in numbers towards the periphery and still detectable several centimeters away from the core lesion. Several decades ago, the diffuse nature of malignant gliomas was recognized by neurosurgeons when super-radical resections using hemispherectomies failed to eradicate these tumors. Local invasiveness eventually leads to regrowth of a recurrent tumor predominantly adjacent to the resection cavity, which is not significantly altered by radiation or chemotherapy. This raises the question of whether invasive glioma cells activate cellular programs that render these cells resistant to conventional treatments. Clinical and experimental data demonstrate that glioma invasion is determined by several independent mechanisms that facilitate the spread of these tumors along different anatomic and molecular structures. A common denominator of this cellular behavior may be cell motility. Gene-expression profiling showed upregulation of genes related to motility, and functional studies demonstrated that cell motility contributes to the invasive phenotype of malignant gliomas. There is accumulating evidence that invasive glioma cells show a decreased proliferation rate and a relative resistance to apoptosis, which may contribute to chemotherapy and radiation resistance. Interestingly, interference with cell motility by different strategies results in increased susceptibility to apoptosis, indicating that this dynamic relationship can potentially be exploited as an anti-invasive treatment paradigm. In this review, we discuss mechanisms of glioma invasion, characteristics of the invasive cell, and consequences of this cellular phenotype for surgical resection, oncologic treatments, and future perspectives for anti-invasive strategies.

Cost of migration: invasion of malignant gliomas and implications for treatment

Tumors of glial origin consist of a core mass and a penumbra of invasive, single cells, decreasing in numbers towards the periphery and still detectable several centimeters away from the core lesion. Several decades ago, the diffuse nature of malignant gliomas was recognized by neurosurgeons when super-radical resections using hemispherectomies failed to eradicate these tumors. Local invasiveness eventually leads to regrowth of a recurrent tumor predominantly adjacent to the resection cavity, which is not significantly altered by radiation or chemotherapy. This raises the question of whether invasive glioma cells activate cellular programs that render these cells resistant to conventional treatments. Clinical and experimental data demonstrate that glioma invasion is determined by several independent mechanisms that facilitate the spread of these tumors along different anatomic and molecular structures. A common denominator of this cellular behavior may be cell motility. Gene-expression profiling showed upregulation of genes related to motility, and functional studies demonstrated that cell motility contributes to the invasive phenotype of malignant gliomas. There is accumulating evidence that invasive glioma cells show a decreased proliferation rate and a relative resistance to apoptosis, which may contribute to chemotherapy and radiation resistance. Interestingly, interference with cell motility by different strategies results in increased susceptibility to apoptosis, indicating that this dynamic relationship can potentially be exploited as an anti-invasive treatment paradigm. In this review, we discuss mechanisms of glioma invasion, characteristics of the invasive cell, and consequences of this cellular phenotype for surgical resection, oncologic treatments, and future perspectives for anti-invasive strategies.

A phase 3 trial of local chemotherapy with biodegradable carmustine (BCNU) wafers (Gliadel wafers) in patients with primary malignant glioma

A previous placebo-controlled trial has shown that biodegradable 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU) wafers (Gliadel wafers) prolong survival in patients with recurrent glioblastoma multiforme. A previously completed phase 3 trial, also placebo controlled, in 32 patients with newly diagnosed malignant glioma also demonstrated a survival benefit in those patients treated with BCNU wafers. Because of the small number of patients in that trial, a larger phase 3 trial was performed to confirm these results. Two hundred forty patients were randomized to receive either BCNU or placebo wafers at the time of primary surgical resection; both groups were treated with external beam radiation postoperatively. The two groups were similar for age, sex, Karnofsky performance status (KPS), and tumor histology. Median survival in the intent-to-treat group was 13.9 months for the BCNU wafer-treated group and 11.6 months for the placebo-treated group (log-rank P -value stratified by country = 0.03), with a 29% reduction in the risk of death in the treatment group. When adjusted for factors affecting survival, the treatment effect remained positive with a risk reduction of 28% ( P = 0.03). Time to decline in KPS and in 10/11 neuroperformance measures was statistically significantly prolonged in the BCNU wafer-treated group ( P </= 0.05). Adverse events were comparable for the 2 groups, except for CSF leak (5% in the BCNU wafer-treated group vs. 0.8% in the placebo-treated group) and intracranial hypertension (9.1% in the BCNU wafer-treated group vs. 1.7% in the placebo group). This study confirms that local chemotherapy with BCNU wafers is well tolerated and offers a survival benefit to patients with newly diagnosed malignant glioma.

Levels of soluble vascular endothelial growth factor (VEGF) receptor 1 in astrocytic tumors and its relation to malignancy, vascularity, and VEGF-A

PURPOSE

Vascular endothelial growth factor (VEGF)-A isa key mediator of angiogenesis in malignant gliomas. Soluble VEGF receptor 1 (sVEGFR-1) can complex VEGF-A and reduce its bioavailability. In several animal models sVEGFR-1 inhibited angiogenesis and tumor growth. We analyzed the levels of endogenous sVEGFR-1 in gliomas of different malignancy grades in relation to tumor vascularity and VEGF-A.

EXPERIMENTAL DESIGN

The concentration of sVEGFR-1 was determined by ELISA in 104 gliomas and normal brain. Levels of sVEGFR-1 were compared with malignancy grade, microvessel density, and VEGF-A concentration. Effects of sVEGFR-1 on glioma extract-induced endothelial cell chemotaxis were analyzed in vitro.

RESULTS

The concentration of sVEGFR-1 correlated with the malignancy grade and was 12-fold higher in glioblastomas than in diffuse astrocytomas (P < 0.001), with intermediate levels for anaplastic astrocytomas. VEGF-A levels were 30-fold higher (P < 0.001) in glioblastomas than in diffuse astrocytomas. The sVEGFR-1:VEGF-A ratio was 0.27 in glioblastomas and 0.70 in diffuse astrocytomas. Both sVEGFR-1 and VEGF-A correlated with microvessel density (P < 0.001) and with each other (P < 0.001); sVEGFR-1 and VEGF-A also correlated with each other when only glioblastomas were analyzed (P = 0.001). In vitro, recombinant sVEGFR-1 inhibited endothelial cell chemotaxis induced by tumor extracts.

CONCLUSIONS

Although absolute levels of sVEGFR-1 are increased in the more malignant gliomas, the sVEGFR-1:VEGF-A ratio is decreased 2.6-fold in glioblastomas compared with diffuse astrocytomas, suggesting that the ensuing increased bioavailability of VEGF-A favors angiogenesis. The inhibition of tumor extract-induced endothelial chemotaxis by sVEGFR-1 suggests that sVEGFR-1 could be useful as an angiogenesis inhibitor in the specific context of human gliomas.

Adsorption of sufentanil to epidural filters and catheters

BACKGROUND AND OBJECTIVE

Stable drug concentrations must be administered to provide adequate patient-controlled epidural analgesia. This study investigated the stability of sufentanil after the epidural delivery system had been flushed with solutions containing the drug.

METHODS

Sufentanil citrate, 5 microg mL(-1) was injected through an epidural catheter system into a glass container. The concentrations of the drug leaving the system, in 1 mL aliquots (1-5 mL) were measured using high-performance liquid chromatography. In the same manner, sufentanil samples were analysed after flushing the filter, as well as after priming the filter and catheter.

RESULTS

ANOVA for repeated measurements demonstrated that sufentanil concentrations remained constant as long as the catheter had been adequately flushed. However, the concentration of sufentanil in the solution exiting the filter was reduced significantly. Hardly any sufentanil could be detected (0.09 +/- 0.01 microg mL(-1), P < 0.001) in the first 1 mL aliquot (probe) leaving the filter. Altogether, 3 mL sufentanil solution was needed to pass through the filter before the baseline values were restored (P > 0.05). The greatest decrease occurred when the whole epidural delivery apparatus (catheter and filter) was primed; to regain baseline values, as much as 4 mL solution was needed to flush the system.

CONCLUSIONS

Sufentanil citrate is adsorbed by the materials used to manufacture systems (catheters, filters) used in epidural anaesthesia. Hence, the epidural catheter system should be primed with sufentanil before connecting it to the patient so as to deliver reliable concentrations.

Local convection enhanced delivery of IL4-Pseudomonas exotoxin (NBI-3001) for treatment of patients with recurrent malignant glioma

PURPOSE

This was an open-label, dose-escalation trial of intratumoral administration of IL-4 Pseudomonas Exotoxin (NBI-3001) in patients with recurrent malignant glioma.

PATIENTS AND METHODS

A total of 31 patients with histologically verified supratentorial grade 3 and 4 astrocytoma were studied. Of these, twenty-five patients were diagnosed with glioblastoma multiforme (GBM) while six were diagnosed with anaplastic astrocytoma (AA). Patients were over 18 years of age and had Karnofsky performance scores > or = 60. Patients were assigned to one of four dose groups in a dose-escalation fashion: 6 microg/ml x 40 ml, 9 microg/ml x 40 ml, 15 microg/ml x 40 ml, or 9 microg/ml x 100 ml of NBI-3001 administered intratumorally via stereotactically placed catheters. Patients were followed with serial MRI scans and clinical assessments every four weeks for the first 16 weeks and then every eight weeks until week 26.

RESULTS

No drug-related systemic toxicity, as evident by lack of hematological or serum chemical changes, was apparent in any patients; treatment-related adverse effects were limited to the central nervous system. No deaths were attributable to treatment. Drug-related Grade 3 or 4 toxicity was seen in 39% of patients in all dose groups and 22% of patients at the maximum tolerated dose of 6 microg/ml x 40 ml. The overall median survival was 8.2 months with a median survival of 5.8 months for the GBM patients. Six-month survival was 52% and 48%, respectively. Gadolinium-enhanced magnetic resonance imaging of the brain showed areas of decreased signal intensity within the tumor consistent with tumor necrosis following treatment in many patients.

CONCLUSIONS

NBI-3001 appears to have an acceptable safety and toxicity profile when administered intratumorally in patients with recurrent malignant glioma.

Invasion as limitation to anti-angiogenic glioma therapy

The inhibition of tumor angiogenesis could be an efficient therapeutic strategy for the treatment of malignant gliomas. Prominent neovascularization is induced by these tumors, and microvascular proliferation is a malignancy grading criterion. However, glioma cells can also invade the brain diffusely over long distances without necessarily requiring angiogenesis. Experimentally, it was shown that especially during early stages of growth in rodent brain, glioma cells can coopt the preexistent host vasculature to recruit their blood supply in the absence of neovascularization. This phenomenon was only observed in orthotopic models in which the tumor cells were implanted into the brain which is a densely vascularized environment, but not in subcutaneous models in which tumor cells are implanted into a virtual space. Using an orthotopic mouse model, we analyzed whether systemic anti-angiogenic therapy with an antibody against the vascular endothelial growth factor receptor-2 (VEGFR-2) could inhibit intracerebral growth of xenografted human glioblastoma cells and what effect this treatment had on tumor morphology and invasiveness. We found that anti-angiogenic therapy inhibited tumor growth by 80% compared to buffer-treated controls. The intratumoral microvessel density was reduced by at least 40% in treated animals compared to controls. However, in mice treated with the anti-VEGFR-2 antibody, we noticed a striking increase in the number and total area of small satellite tumors clustered around the primary mass. These satellites usually contained central vessel cores, and tumor cells often had migrated along blood vessels over long distances to eventually reach the surface and spread in the subarachnoid space. Systemic anti-angiogenic therapy can thus apparently increase the invasiveness of gliomas in the orthotopic model. Tumor cell invasion was tightly associated with preexistent blood vessels, suggesting that increased cooption of the host vasculature could represent a compensatory mechanism that is selected for by inhibiting adequate tumor vascularization.