Nicolai El Hindy

Implications of Dll4-Notch signaling activation in primary glioblastoma multiforme

BACKGROUND Glioblastoma multiforme (GBM) is a highly aggressive brain tumor characterized by massive neovascularization, necrosis, and intense resistance to therapy. Deregulated Notch signaling has been implicated in the formation and progression of different malignancies. The present study attempted to investigate the activation status of Dll4-Notch signaling in primary human GBM and its association with vascular and clinical parameters in patients. METHODS Major components of Dll4-Notch signaling were examined by real-time reverse-transcription polymerase chain reaction (PCR), Western blotting, and immunohistochemistry in GBM (n = 26) and control (n = 11) brain tissue. The vascular pattern (VP) and microvascular density (MVD) were analyzed after laminin immunostaining. O6-Methylguanine-methyltransferase (MGMT) promoter methylation in GBM samples was detected by methylation-specific PCR. RESULTS The mRNA levels of Dll4, Jagged1, Notch1, Notch4, Hey1, Hey2, Hes1, and VEGF were 3.12-, 3.58-, 3.37-, 5.77-, 4.89-, 3.13-, 6.62-, and 32.57-fold elevated, respectively, in GBM samples, compared with the controls. Western blotting revealed a 4-, 3.7-, and 45.6-fold upregulation of Dll4, Notch1, and Hey1, respectively, accompanied by a downregulation of PTEN expression and an increase in the expression of p-Akt and VEGF. Immunostaining located the immunoreactivity of Dll4 and Notch1 in endothelial cells, microglia/macrophages, tumor cells, and astrocytes. Furthermore, the upregulation of Dll4-Notch signaling components was correlated to a low MVD and was potentially related to a classic VP, tumor edema, and MGMT promoter methylation. CONCLUSIONS The upregulation of Dll4-Notch signaling components was found in a subset of GBM samples and was associated with some angiogenic and clinical parameters. These findings highlight this signaling pathway as a potential therapeutic target for patients with GBM who show an activation of Dll4-Notch signaling.

The venous angioarchitecture of sporadic cerebral cavernous malformations: a susceptibility weighted imaging study at 7 T MRI

Background and purpose To test the hypothesis that sporadic cerebral cavernous malformations (CCMs) are systematically associated with venous malformations (VMs) using susceptibility weighted imaging (SWI) at 7 Tesla (T) field MRI. Methods A prospective unselected series of 20 patients with symptomatic or asymptomatic sporadic CCM diagnosed using 1.5 T MRI was additionally scanned using high resolution (250 µm2 in-plane) SWI at 7 T MRI. Imaging data were analysed to examine the presence and formation of CCM associated venous vessel structures. Interobserver agreement was assessed using kappa statistics. Results In the 20 patients harbouring 23 CCMs, a solitary or multiple venous drainage was found in all lesions. A ‘typical’ VM was found in seven lesions. In the other cases, associated abnormal venous structures were also depicted although they appeared structurally different. Excellent interobserver agreement was achieved (95% confidence interval 0.92 to 0.99). Conclusions Our data support previous assumptions that sporadic CCMs are systematically associated with local venous abnormalities involving larger outflow vessels. However, the typical appearance of a VM was not confirmed in all cases. The role of the venous environment in the pathomechanism of CCMs remains unclear.

Association of the CC genotype of the regulatory BCL2 promoter polymorphism (-938C>A) with better 2-year survival in patients with glioblastoma multiforme.

OBJECT Bcl-2 plays a key role in the downregulation of apoptosis and proliferation and leads to increased chemoresistance in glioblastoma multiforme (GBM). The authors investigated the role of a common regulatory single-nucleotide polymorphism (-938C>A), which is located in the inhibitory P2 promoter of BCL2. METHODS Data from 160 patients suffering from GBM were retrospectively evaluated. Study inclusion criteria consisted of available DNA and, in patients still alive, a follow-up of at least 24 months. Results were analyzed with respect to the basic clinical data, type of surgical intervention (gross-total resection [GTR] versus stereotactic biopsy [SB]), adjuvant therapy, MGMT promoter methylation, and survival at the 2-year follow-up. RESULTS At the 2-year follow-up, 127 (79.4%) of the 160 patients had died. Kaplan-Meier curves revealed a significantly higher rate of survival for homo- and heterozygous C-allele carriers (p = 0.031). In the GTR group, the survival rate was 47.1% for homozygous C-allele carriers, 32.0% for heterozygous C-allele carriers, and only 21.4% for homozygous A-allele carriers (p = 0.024). The SB group showed no genotype-dependent differences. Multivariable Cox regression revealed that the BCL2 (-938AA) genotype was an independent negative prognostic factor for 2-year survival in the GTR group according to the BCL2 (-938CC) genotype reference group (hazard ratio 2.50, 95% CI 1.14-5.48, p = 0.022). CONCLUSIONS These results suggested that the (-938C>A) polymorphism is a survival prognosticator as well as a marker for a high-risk group among patients with GBM who underwent GTR.

The functional Aquaporin 1 −783G/C-polymorphism is associated with survival in patients with glioblastoma multiforme

Despite a dismal prognosis, variability exists regarding the survival‐time in patients with glioblastoma‐multiforme (GBM), which may be explained by genetic variation. A possible candidate‐gene for such variation is Aquaporin‐1 (AQP1), since Aquaporin‐1‐expression influences the pathogenesis and outcome of various malignancies. Functional genetic variants in the promoter of AQP1, modifying Aquaporin‐1‐expression, could be associated with altered survival in patients with GBM.

Study of angiogenic signaling pathways in hemangioblastoma

Hemangioblastoma (HB) is mainly located in the brain and the spinal cord. The tumor is composed of two major components, namely neoplastic stromal cells and abundant microvessels. Thus, hyper‐vascularization is the hallmark of this tumor. Despite the identification of germline and/or epigenetic mutations of Von Hippel Lindau (VHL) gene as an important pathogenic mechanism of HB, little is known about the molecular signaling involved in this highly vascularized tumor. The present study investigated the key players of multiple angiogenic signaling pathways including VEGF/VEGFR2, EphB4/EphrinB2, SDF1α/CXCR4 and Notch/Dll4 pathways in surgical specimens of 22 HB. The expression of key angiogenic factors was detected by RT2‐PCR and Western blot. Immunofluorescent staining revealed the cellular localization of these proteins. We demonstrated a massive upregulation of mRNA levels of VEGF and VEGFR2, CXCR4 and SDF1α, EphB4 and EphrinB2, as well as the main components of Dll4‐Notch signaling in HB. An increase in the protein expression of VEGF, CXCR4 and the core‐components of Dll4‐Notch signaling was associated with an activation of Akt and Erk1/2 and accompanied by an elevated expression of PCNA. Immuofluorescent staining revealed the expression of VEGF and CXCR4 in endothelial cells as well as in tumor cells. Dll4 protein was predominantly found in tumor cells, whereas EphB4 immunoreactivity was exclusively detected in endothelial cells. We conclude that multiple key angiogenic pathways were activated in HB, which may synergistically contribute to the abundant vascularization in this tumor. Identification of these aberrant pathways provides potential targets for a possible future application of anti‐angiogenic therapy for this tumor, particularly when a total surgical resection becomes difficult due to the localization or multiplicity of the tumor.

Spinal metastasis from malignant meningeal intracranial hemangiopericytoma: one-staged percutaneous Onyx™ embolization and resection - a technical innovation

BackgroundWe are the first to report one-staged resection of a spinal metastasis from malignant cranial hemangiopericytoma after preoperative Onyx™-20 embolization by direct percutaneous puncture.Spinal metastases from cranial hemangiopericytoma are extremely rare. Surgical morbidity of these highly vascularized tumours results mainly from excessive blood loss. Preoperative embolization of hyper vascular tumours has been used to reduce intraoperative blood loss for a long time. To avoid complications from arterial catheter intervention, direct percutaneous puncture has been advocated as a safe and effective alternative.MethodsA 46-year-old man with a history of malignant cranial hemangiopericytoma deriving from the left frontal skull base presented with a short history of lower back pain. A magnetic resonance imaging scan revealed an intra- and extra spinal mass lesion of the thoracic spine at Th 12. Indication for tumour resection was made and the patient’s written consent was obtained. Preoperatively, arterial catheter angiography was performed to reveal the tumour’s angioarchitecture, revealing high-flow arteriovenous shunts. In order to impede the expected perioperative blood loss, tumour embolization by direct percutaneous puncture and application of Onyx™-20 was performed prior to surgery.ResultsAfter percutaneous Onyx™-20 embolization, complete and safe resection of the lesion could be achieved. There was only minimal blood loss perioperatively. A pathohistological report confirmed malignant, anaplastic hemangiopericytoma.ConclusionsIn our case Onyx™-20 embolization via direct percutaneous puncture of a highly vascularized tumour was shown to be a safe and efficient tool prior to surgery. Despite high-flow arteriovenous shunts, direct percutaneous administration of non-adhesive ethanol liquid was an efficient alternative to transarterial catheter embolization. The perioperative blood loss could be substantially diminished.

Intracerebral metastases of malignant melanoma and their recurrences—A clinical analysis

INTRODUCTION Brain metastases (BM) commonly occur in patients with metastatic malignant melanoma (MM). Prognosis is poor even with maximal therapy. The aim of the current study was to retrospectively evaluate patients with BM of MM who were treated neurosurgically with respect to clinical presentation, recurrent disease, survival and factors affecting survival. PATIENTS AND METHODS Thirty-four patients (19f/15m) with BM of MM were treated in our hospital between 2000 and 2010. Patient data were analysed, survival was examined using Kaplan-Meier-estimates and factors affecting prognosis were evaluated using uni- and multivariate analysis. RESULTS Twenty-two patients (64.7%) had a single BM, whereas twelve patients (35.3%) revealed two or more lesions. Median survival for patients with a single BM was 13.0 months (95%-CI 9.3-16.7 months), this was significantly (p=0.014) better than for patients with two or more BM (median 5.0, 95%-CI 3.4-14.6 months). Nineteen patients (55.9%) developed an intracranial relapse after microsurgical resection of a first lesion. Patients with an isolated intracerebral relapse survived significantly (p=0.003) longer than those with systemic progression (median 6.0, 95%-CI 0.0-15.3 months vs median 3.0, 95%-CI 1.7-4.3 months). Similarly, patients with a high performance status showed significantly (p=0.001) prolonged survival (median 7.0, 95%-CI 0.0-19.9 months vs median 1.0, 95%-CI 0.0-2.2 months). Eleven out of nineteen patients (57.9%) underwent either another microsurgical resection (n=6) or stereotactic radiosurgery (n=5). These patients remained on a high performance status even after aggressive therapy. DISCUSSION Even though the prognosis for patients with BM of MM is generally poor, patients with a single BM can benefit from microsurgical resection. However, there is a high risk of intracranial relapse. In selected patients with a good performance status and recurrent intracranial disease, recurrent local therapy can be justified and useful.

Outcome After Clipping of Unruptured Intracranial Aneurysms Depends on Caseload

OBJECTIVE Although most neurovascular centers currently have a coil first policy, the percentage of coiled versus clipped aneurysms, as well as treatment outcomes, varies strongly between these centers. This study evaluates the impact of an increase in clipping caseload on treatment outcome in a large single-center series. METHODS All consecutive patients who underwent microsurgical clipping of unruptured intracranial aneurysms between January 2003 and April 2014 in our department were analyzed retrospectively. According to the change of the chairman in the neurosurgical department (1 September 2008) with a subsequent increase in the clipping volume, the entire cohort was divided into 2 groups with equal time intervals (historic and current cohorts). RESULTS There were 94 clipped unruptured intracranial aneurysms in the historic cohort and 252 in the current cohort. Unfavorable outcome at 6 months postoperatively (defined as modified Rankin Score >2) was observed in 8 cases (8.5%) in the historic cohort and 7 cases (2.8%) in the current cohort (P < 0.0001). The surgical mortality decreased from 3.2% to 0%. Cerebral infarction on postoperative computed tomography scan was observed in 25 cases (26.6%) in the historic cohort and 19 cases (7.5%) in the current cohort (P < 0.0001). Within the current cohort, there was a progressive improvement of surgical outcome over the time. CONCLUSIONS The improvement of the surgical outcome after increasing the clipping caseload underlines the importance of sufficient surgical volume for maintenance of competitive treatment results.

Downregulation of programmed cell death 10 is associated with tumor cell proliferation, hyperangiogenesis and peritumoral edema in human glioblastoma

BackgroundNeovascularization and peritumoral edema are hallmarks of glioblastoma (GBM). Programmed cell death 10 (PDCD10) plays a pivotal role in regulating apoptosis, neoangiogenesis and vessel permeability and is implicated in certain tumor signaling pathways. However, little is known about PDCD10 in GBM. We aimed to investigate the expression pattern of PDCD10 and to identify the association of its expression with some molecular and clinical parameters in human GBM.MethodsmRNA and protein expression of PDCD10 were examined respectively by real-time RT-PCR and Western blotting in GBM (n = 27), astrocytoma grade II (n = 13) and control (n = 11). The protein level of p-Akt and GFAP was detected by Western blot. Double-imunofluorecent staining was performed to reveal the cellular expression profile of PDCD10. Brain edema and microvascular density (MVD) were respectively analyzed based on pre-operative MRI and after laminin immnostaining. MGMT promoter methylation was detected by methylation specific PCR.ResultsmRNA and protein levels of PDCD10 were significantly downregulated in GBM, concomitantly accompanied by the activation of Akt. PDCD10 immunoreactivity was absent in proliferating tumor cells, endothelial cells and GFAP-positive cells, but exclusively present in the hypoxic pseudopalisading cells which underwent apoptosis. Moreover, loss of PDCD10 was associated with a higher MVD and a more severe peritumoral edema but not with MGMT promoter methylation in GBM.ConclusionWe report for the first time that PDCD10 expression is downregulated in GBM, which is associated with the activation of Akt signaling protein. PDCD10 is potentially implicated in tumor proliferation and apoptosis, hyperangiogenesis and peritumoral edema in GBM.

Simultaneous 11C-Methionine Positron Emission Tomography/Magnetic Resonance Imaging of Suspected Primary Brain Tumors.

Introduction The objective of this study was to assess the diagnostic value of integrated 11C- methionine PET/MRI for suspected primary brain tumors, in comparison to MRI alone. Material and Methods Forty-eight consecutive patients with suspected primary brain tumor were prospectively enrolled for an integrated 11C-methionine PET/MRI. Two neuro-radiologists separately evaluated the MRI alone and the integrated PET/MRI data sets regarding most likely diagnosis and diagnostic confidence on a 5-point scale. Reference standard was histopathology or follow-up imaging. Results Fifty-one suspicious lesions were detected: 16 high-grade glioma and 25 low-grade glioma. Ten non-malignant cerebral lesions were described by the reference standard. MRI alone and integrated PET/MRI each correctly classified 42 of the 51 lesions (82.4%) as neoplastic lesions (WHO grade II, III and IV) or non-malignant lesions (infectious and neoplastic lesions). Diagnostic confidence for all lesions, low-grade astrocytoma and high-grade astrocytoma (3.7 vs. 4.2, 3,1 vs. 3.8, 4.0 vs. 4,7) were significantly (p < 0.05) better with integrated PET/MRI than in MRI alone. Conclusions The present study demonstrates the high potential of integrated 11C-methionine-PET/MRI for the assessment of suspected primary brain tumors. Although integrated methionine PET/MRI does not lead to an improvement of correct diagnoses, diagnostic confidence is significantly improved.