Sudden unexpected death in epilepsy (SUDEP) is a fatal complication of epilepsy in which brainstem spreading depolarization may play a pivotal role, as suggested by animal studies. However, patiotemporal details of spreading depolarization occurring in relation to fatal seizures have not been investigated. In addition, little is known about behavioural and neurophysiological features that may discriminate spontaneous fatal from non-fatal seizures. Transgenic mice carrying the missense mutation S218L in the a 1A subunit of Ca v 2.1 (P/Q-type) Ca 2+ channels exhibit enhanced excitatory neurotransmission and increased susceptibility to spreading depolarization. Homozygous Cacna1a S218L mice show spontaneous non-fatal and fatal seizures, occurring throughout life, resulting in reduced life expectancy. To identify characteristics of fatal and non-fatal spontaneous seizures, we compared behavioural and electrophysiological seizure dynamics in freely-behaving homozygous Cacna1a S218L mice. To gain insight on the role of brainstem spreading depolarization in SUDEP, we studied the spatiotemporal distribution of spreading depolarization in the context of seizure-related death. Spontaneous and electrically-induced seizures were investigated by video monitoring and electrophysiological recordings in freely-behaving Cacna1a S218L and wild-type mice. Homozygous Cacna1a S218L mice showed multiple spontaneous tonic-clonic seizures and died from SUDEP in adulthood. Death was preceded by a tonic-clonic seizure terminating with hindlimb clonus, with suppression of cortical neuronal activity during and after the seizure. Induced seizures in freely-behaving homozygous Cacna1a S218L mice were followed by multiple spreading depolarizations and death. In wild-type or heterozygous Cacna1a S218L mice, induced seizures and spreading depolarization were never followed by death. To identify temporal and regional features of seizure-induced spreading depolarization related to fatal outcome, diffusion-weighted MRI was performed in anaesthetized homozygous Cacna1a S218L and wild-type mice. In homozygous Cacna1a S218L mice, appearance of seizure-related spreading depolarization in the brainstem correlated with respiratory arrest that was followed by cardiac arrest and death. Recordings in freely-behaving homozygous Cacna1a S218L mice confirmed brainstem spreading depolarization during spontaneous fatal seizures. These data underscore the value of the homozygous Cacna1a S218L mouse model for identifying discriminative features of fatal compared to non-fatal seizures, and support a key role for cortical neuronal suppression and brainstem spreading depolarization in SUDEP pathophysiology.

Diffusion tensor imaging (DTI) and quantitative T(2) magnetic resonance imaging (MRI) were used to characterize ex vivo the white matter damage at 3 and 8 weeks following dorsal column transection (DC Tx) injury at the cervical level C5 of rat spinal cords. Luxol Fast Blue (LFB) and myelin basic protein (MBP) staining was used to assess myelin damage, and neurofilament-H in combination with neuron specific beta-III-tubulin (NF/Tub) staining was used to assess axonal damage. Average values of myelin water fraction (MWF), fractional anisotropy (FA), longitudinal diffusivity (D(long)), transverse diffusivity (D(trans)), and average diffusivity (D(ave)) were calculated in the fasciculus gracilis, fasciculus cuneatus, and the dorsal corticospinal tract (CST) 5 mm cranial, as well as 5 and 10 mm caudal to injury and correlated with histology. These tracts were selected as these contain bundles of parallel ascending and descending axons in very circumscribed areas with little intermingling of other axonal populations. Axonal and myelin degeneration occur cranial to injury in the funiculus gracilis and caudal to injury in the CST. Both MWF and D(trans) showed significant correlation with LFB staining at 3 weeks (0.64 and -0.49, respectively) and 8 weeks post-injury (0.88 and -0.71, respectively). Both D(long) and FA correlated significantly with NF/Tub staining at 3 weeks post-injury (0.78 and 0.64, respectively), while only D(long) displayed significant correlation 8 weeks post-injury (0.58 and 0.33, respectively). This study demonstrates that quantitative MRI can accurately characterize white matter damage in DC Tx model of injury in rat spinal cord.

BackgroundChemotherapy for glioblastoma (GBM) patients is compromised in part by poor perfusion in the tumor. The present study evaluates how treatment with liposomal formulation of irinotecan (Irinophore C™), and other liposomal anticancer drugs, influence the tumor vasculature of GBM models grown either orthotopically or subcutaneously.MethodsLiposomal vincristine (2 mg/kg), doxorubicin (Caelyx®; 15 mg/kg) and irinotecan (Irinophore C™; 25 mg/kg) were injected intravenously (i.v.; once weekly for 3 weeks) in Rag2M mice bearing U251MG tumors. Tumor blood vessel function was assessed using the marker Hoechst 33342 and by magnetic resonance imaging-measured changes in vascular permeability/flow (Ktrans). Changes in CD31 staining density, basement membrane integrity, pericyte coverage, blood vessel diameter were also assessed.ResultsThe three liposomal drugs inhibited tumor growth significantly compared to untreated control (p < 0.05-0.001). The effects on the tumor vasculature were determined 7 days following the last drug dose. There was a 2-3 fold increase in the delivery of Hoechst 33342 observed in subcutaneous tumors (p < 0.001). In contrast there was a 5-10 fold lower level of Hoechst 33342 delivery in the orthotopic model (p < 0.01), with the greatest effect observed following treatment with Irinophore C. Following treatment with Irinophore C, there was a significant reduction in Ktrans in the orthotopic tumors (p < 0.05).ConclusionThe results are consistent with a partial restoration of the blood-brain barrier following treatment. Further, treatment with the selected liposomal drugs gave rise to blood vessels that were morphologically more mature and a vascular network that was more evenly distributed. Taken together the results suggest that treatment can lead to normalization of GBM blood vessel the structure and function. An in vitro assay designed to assess the effects of extended drug exposure on endothelial cells showed that selective cytotoxic activity against proliferating endothelial cells could explain the effects of liposomal formulations on the angiogenic tumor vasculature.

Migraine is characterized by severe headaches that can be preceded by an aura likely caused by cortical spreading depression (SD). The antiepileptic pregabalin (Lyrica) shows clinical promise for migraine therapy, although its efficacy and mechanism of action are unclear. As detected by diffusion-weighted MRI (DW-MRI) in wildtype (WT) mice, the acute systemic administration of pregabalin increased the threshold for SD initiation in vivo. In familial hemiplegic migraine type 1 mutant mice expressing human mutations (R192Q and S218L) in the Ca V 2.1 (P/Q-type) calcium channel subunit, pregabalin slowed the speed of SD propagation in vivo. Acute systemic administration of pregabalin in vivo also selectively prevented the migration of SD into subcortical striatal and hippocampal regions in the R192Q strain that exhibits a milder phenotype and gain of Ca V 2.1 channel function. At the cellular level, pregabalin inhibited glutamatergic synaptic transmission differentially in WT, R192Q, and S218L mice. The study describes a DW-MRI analysis method for tracking the progression of SD and provides support and a mechanism of action for pregabalin as a possible effective therapy in the treatment of migraine.familial hemiplegic migraine type 1 | migraine | diffusion-weighted MRI | voltage-gated calcium channel | gabapentinoids

Purpose: To examine the antitumor effects of Irinophore C, a nanopharmaceutical formulation of irinotecan, on the tissue morphology and function of tumor vasculature in HT-29 human colorectal tumors. Experimental Design: Fluorescence microscopy was used to map and quantify changes in tissue density, tumor vasculature, hypoxia, and the distribution of Hoechst 33342, a perfusion marker, and the anticancer drug, doxorubicin. Noninvasive magnetic resonance imaging was used to quantify K trans , the volume transfer constant of a solute between the blood vessels and extracellular tissue compartment of the tumor, as a measure of vascular function. Following treatment with Irinophore C, 19F magnetic resonance spectroscopy was used to monitor the delivery of 5-fluorouracil (5-FU) to the tumor tissue, whereas scintigraphy was used to quantify the presence of bound [ ), and 5-FU (P = 0.0002) in the tumor. Vascular endothelial growth factor and interleukin-8, two proangiogenic factors, were down-regulated, whereas the antiangiogenic factorTIMP-1was up-regulated in Irinophore C-treated tumors. Conclusions: Irinophore C treatment improves the vascular function of the tumor, thereby reducing tumor hypoxia and increasing the delivery and accumulation of a second drug. Reducing hypoxia would enhance radiotherapy, whereas improving delivery of a second drug to the tumor should result in higher cell kill.The clinical management of metastatic disease originating from colon/colorectal cancer remains challenging. The liver is the most common site of distant metastases for colorectal cancer, with 70% of patients presenting with liver metastases followed by the lungs, bone, and brain (1, 2). At present, the only cure is complete surgical removal of the primary tumor if diagnosed early; however, up to 45% of these patients still relapse with metastatic disease. Standard of care for first-line therapy in patients is a combination of 5-fluorouracil (5-FU; plus leucovorin) with either irinotecan (FOLFIRI) or oxaliplatin (FOLFOX; ref.3). The treatments are associated with prolonged median survivals of 18 to 21 months. Capecitabine, an oral fluoropyrimidine carbamate, has also been used in combination with 5-FU, and clinical data suggest that this combination is comparable with the FOLFIRI and FOLFOX regimens (4, 5). In practice, however, combination therapy with capecitabine is limited because of severe toxicities such as hand-foot syndrome, diarrhea, nausea, vomiting, and bone marrow suppression (4, 5). More recently, monoclonal antibodies targeting the epidermal growth factor receptor, such as cetuximab and panitumumab, have been used in combination with standard chemotherapy with promising results (6). The safety and efficacy of bevacizumab, the monoclonal antibody that targets vascular endothelial growth factor (VEGF; ref. 7), in combination with FOLFIRI or FOLFOX, was also evaluated recently (8,9). Although both studies were carried out with small Cancer Therapy: Preclinical