Successful treatment of leptomeningeally metastasised pituitary carcinoma with temozolomide.

A 69-year-old man presented with leptomeningeally metastasised pituitary carcinoma, rapidly progressing despite previous treatment with resection, radiotherapy and cabergoline. The patient received temozolomide chemotherapy, resulting in a complete clinical, radiological and biochemical response after 14 cycles, which has been maintained since then. This case lends further support to the role of temozolomide in refractory pituitary tumours.

Quantitative Intracranial Atherosclerotic Plaque Characterization at 7T MRI: An Ex Vivo Study with Histologic Validation.

BACKGROUND AND PURPOSE: In recent years, several high-resolution vessel wall MR imaging techniques have emerged for the characterization of intracranial atherosclerotic vessel wall lesions in vivo. However, a thorough validation of MR imaging results of intracranial plaques with histopathology is still lacking. The aim of this study was to characterize atherosclerotic plaque components in a quantitative manner by obtaining the MR signal characteristics (T1, T2, T2*, and proton density) at 7T in ex vivo circle of Willis specimens and using histopathology for validation. MATERIALS AND METHODS: A multiparametric ultra-high-resolution quantitative MR imaging protocol was performed at 7T to identify the MR signal characteristics of different intracranial atherosclerotic plaque components, and using histopathology for validation. In total, 38 advanced plaques were matched between MR imaging and histology, and ROI analysis was performed on the identified tissue components. RESULTS: Mean T1, T2, and T2* relaxation times and proton density values were significantly different between different tissue components. The quantitative T1 map showed the most differences among individual tissue components of intracranial plaques with significant differences in T1 values between lipid accumulation (T1 = 838 ± 167 ms), fibrous tissue (T1 = 583 ± 161 ms), fibrous cap (T1 = 481 ± 98 ms), calcifications (T1 = 314 ± 39 ms), and the intracranial arterial vessel wall (T1 = 436 ± 122 ms). CONCLUSIONS: Different tissue components of advanced intracranial plaques have distinguishable imaging characteristics with ultra-high-resolution quantitative MR imaging at 7T. Based on this study, the most promising method for distinguishing intracranial plaque components is T1-weighted imaging.

Differential expression and clinical significance of three inflammation-related microRNAs in gangliogliomas.

PURPOSE: miR21, miR146, and miR155 represent a trio of microRNAs which has been shown to play a key role in the regulation of immune and inflammatory responses. In the present study, we investigated the differential expression and clinical significance of these three miRNAs in glioneuronal tumors (gangliogliomas, GGs) which are characterized by prominent activation of the innate immune response. METHODS: The expression levels of miR21, miR146, and miR155 were evaluated using Taqman PCR in 34 GGs, including 15 cases with sufficient amount of perilesional cortex. Their expression was correlated with the tumor features and the clinical history of epilepsy. In addition, in situ hybridization was used to evaluate their cellular distribution in both tumor and peritumoral cortex. RESULTS: Increased expression of miR146a was observed in both tumor and peritumoral cortex compared to control samples. miR146a was detected in both neuronal and astroglial cells. Tumor and peritumoral miR146a expression was negatively correlated with frequency of seizures and the density of activated microglial cells. Neuronal and astroglial expression was observed for both miR21 and miR155 with increased expression of miR21 within the tumor and miR155 in the peritumoral region. Negative correlations were observed between the miRNA levels and the expression of putative targets within the astroglial component of the tumor. CONCLUSION: We report a differential regulation of three miRNAs, known to be related to inflammation, in both tumor and peritumoral cortex of patients with GG. Moreover, our findings suggest a functional relationship between miR146a expression and epilepsy, either directly in epileptogenesis or as modulation of seizure activity.

Imaging the intracranial atherosclerotic vessel wall using 7T MRI: initial comparison with histopathology.

BACKGROUND AND PURPOSE: Several studies have attempted to characterize intracranial atherosclerotic plaques by using MR imaging sequences. However, dedicated validation of these sequences with histology has not yet been performed. The current study assessed the ability of ultra-high-resolution 7T MR imaging sequences with different image contrast weightings to image plaque components, by using histology as criterion standard. MATERIALS AND METHODS: Five specimens of the circle of Wills were imaged at 7T with 0.11 × 0.11 mm in-plane-resolution proton attenuation-, T1-, T2-, and T2*-weighted sequences (through-plane resolution, 0.11-1 mm). Tissue samples from 13 fiducial-marked locations (per specimen) on MR imaging underwent histologic processing and atherosclerotic plaque classification. Reconstructed MR images were matched with histologic sections at corresponding locations. RESULTS: Forty-four samples were available for subsequent evaluation of agreement or disagreement between plaque components and image contrast differences. Of samples, 52.3% (n = 23) showed no image contrast heterogeneity; this group comprised solely no lesions or early lesions. Of samples, 25.0% (n = 11, mostly advanced lesions) showed good correlation between the spatial organization of MR imaging heterogeneities and plaque components. Areas of foamy macrophages were generally seen as proton attenuation-, T2-, and T2*- hypointense areas, while areas of increased collagen content showed more ambiguous signal intensities. Five samples showed image-contrast heterogeneity without corresponding plaque components on histology; 5 other samples showed contrast heterogeneity based on intima-media artifacts. CONCLUSIONS: MR imaging at 7T has the image contrast capable of identifying both focal intracranial vessel wall thickening and distinguishing areas of different signal intensities spatially corresponding to plaque components within more advanced atherosclerotic plaques.

Expression of neurodegenerative disease-related proteins and caspase-3 in glioneuronal tumours.

AIMS: Recent evidence supports the activation of mechanisms underlying cellular ageing and neurodegeneration in developmental lesions associated with epilepsy. The present study examined the ongoing cell injury and vulnerability to neuronal degeneration in glioneuronal tumours (GNT). METHODS: We evaluated a series of GNT (n = 31 gangliogliomas, GG and n = 30 dysembryoplastic neuroepithelial tumours, DNT). Sections were processed for immunohistochemistry using markers for the evaluation of caspase-3 and neurodegeneration-related proteins/pathways and their expression was correlated with the tumour features and the clinical history of epilepsy. RESULTS: Both GG and DNT specimens contained caspase-3-positive cells. In GG, expression of activated caspase-3 was negatively correlated the with the BRAF V600E mutation status. We also observed an abnormal expression of death receptor-6 and ß-amyloid precursor protein (APP). Moreover, dysplastic neurones expressed p62, phosphorylated (p)TDP43 and pTau. Double labelling experiments showed colocalization of phosphorylated S6 (marker of mammalian target of rapamycin, mTOR, pathway activation) with pTau and p62. In GG, neuronal p62 expression was positively correlated with pS6. The immunoreactivity score (IRS) of caspase-3, APP, DR6, p62 and pTDP43 were found to be significantly higher in GG than in DNT. Expression of APP, DR6, pTau (in GG and DNT) and caspase-3 (in GG) positively correlated with duration of epilepsy. In GG, the expression of neuronal caspase-3, DR6 and glial p62 was associated with a worse postoperative seizure outcome. CONCLUSIONS: Our observations in GNT provide evidence of premature activation of mechanisms of neurodegeneration which are associated with the clinical course of epilepsy in patient with GG.

Toll-like receptor signaling in amyotrophic lateral sclerosis spinal cord tissue.

Increasing evidence indicates that inflammatory responses could play a critical role in the pathogenesis of motor neuron injury in amyotrophic lateral sclerosis (ALS). Recent findings have underlined the role of Toll-like receptors (TLRs) and the receptor for advanced glycation endproducts (RAGE) in the regulation of both innate and adaptive immunity in different pathologies associated with neuroinflammation. In the present study we investigated the expression and cellular distribution of TLR2, TLR4, RAGE and their endogenous ligand high mobility group box 1 (HMGB1) in the spinal cord of control (n=6) and sporadic ALS (n=12) patients. The immunohistochemical analysis of TLR2, TLR4 and RAGE showed increased expression in reactive glial cells in both gray (ventral horn) and white matter of ALS spinal cord. TLR2 was predominantly detected in cells of the microglia/macrophage lineage, whereas the TLR4 and RAGE was strongly expressed in astrocytes. Real-time quantitative PCR analysis confirmed the increased expression of both TLR2 and TLR4 and HMGB1 mRNA level in ALS patients. In ALS spinal cord, HMGB1 signal is increased in the cytoplasm of reactive glia, indicating a possible release of this molecule from glial cells. Our findings show increased expression of TLR2, TLR4, RAGE and HMGB1 in reactive glia in human ALS spinal cord, suggesting activation of the TLR/RAGE signaling pathways. The activation of these pathways may contribute to the progression of inflammation, resulting in motor neuron injury. In this context, future studies, using animal models, will be important to achieve a better understanding of these signaling pathways in ALS in view of the development of new therapeutic strategies.

Expression patterns of AMOG in developing human cortex and malformations of cortical development.

Adhesion molecule on glia (AMOG) mediates neuronal migration during development and ion homeostasis. Recently, AMOG has been identified as a regulator of the Pi3K-mTOR signaling pathway. In the present study, we investigated the expression pattern of AMOG in human cortex during development and in focal malformations of cortical development. In the developing human cortex, AMOG expression was detected in the cortical plate at 13 gestational weeks and increased in later gestational ages. In adult human control cortex, a diffuse immunoreactivity pattern was observed for AMOG in the grey matter. In the white matter, AMOG was expressed in perivascular astrocytes. In focal cortical dysplasia (n=6) and cortical tubers (n=6), the diffuse AMOG expression pattern was reduced in the grey matter. However, AMOG immunoreactivity was observed in reactive astrocytes and strong perisomatic staining was detected in balloon and giant cells. Double-labeling showed co-localization of AMOG with the precursor cell marker CD34 and phosphorylated S6, used as a marker of mTOR activation. The AMOG expression pattern, with altered cellular distribution, observed in malformations of cortical development suggests that AMOG might contribute to the abnormal cortical development via mTOR activation. Whether dysfunction of AMOG might influence the ionic and osmotic regulation, contributing to neuronal hyperexcitability, deserves further investigation.

CB1 and CB2 cannabinoid receptor expression during development and in epileptogenic developmental pathologies.

Recent data support the involvement of the endocannabinoid signaling in early brain development, as well as a key role of cannabinoid receptors (CBR) in pathological conditions associated with unbalanced neuronal excitability and inflammation. Using immunocytochemistry, we explored the expression and cellular pattern of CBR 1 and 2 (CB1 and CB2) during prenatal human cortical development, as well as in focal malformations of cortical development associated with intractable epilepsy (focal cortical dysplasia; cortical tubers in patients with the tuberous sclerosis complex and glioneuronal tumors). Strong CB1 immunoreactivity was detected in the cortical plate in developing human brain from the earliest stages tested (gestational week 9) and it persisted throughout prenatal development. Both cannabinoid receptors were not detected in neural progenitor cells located in the ventricular zone. Only CB1 was expressed in the subventricular zone and in Cajal-Retzius cells in the molecular zone of the developing neocortex. CB2 was detected in cells of the microglia/macrophage lineage during development. In malformations of cortical development, prominent CB1 expression was demonstrated in dysplastic neurons. Both CBR were detected in balloon/giant cells, but CB2 appeared to be more frequently expressed than CB1 in these cell types. Reactive astrocytes were mainly stained with CB1, whereas cells of the microglia/macrophage lineage were stained with CB2. These findings confirm the early expression pattern of cannabinoid receptors in the developing human brain, suggesting a function for CB1 in the early stages of corticogenesis. The expression patterns in malformations of cortical development highlight the role of cannabinoid receptors as mediators of the endocannabinoid signaling and as potential pharmacological targets to modulate neuronal and glial cell function in epileptogenic developmental pathologies.

Immunohistochemical characterization of the out-of frame splice variants GFAP Delta164/Deltaexon 6 in focal lesions associated with chronic epilepsy.

GFAP Delta164/Deltaexon 6 are two out-of frame splice variants of GFAP. The aim of this study was to investigate the distribution of GFAP Delta164/Deltaexon 6 expressing cells, in focal lesions associated with chronic intractable epilepsy, in light of the increasing interest in the role of specific astrocyte subtypes in epilepsy. Immunocytochemical analysis, using an antibody against Delta164 and Deltaexon6 (GFAP+1), was performed in surgical specimens of patients with hippocampal sclerosis (HS), focal cortical dysplasia type IIB (FCD), cortical tubers of tuberous sclerosis complex (TSC), glioneuronal and glial tumors. Expression of GFAP+1 was also evaluated in developing and adult human control cortex and hippocampus. GFAP+1 immunoreactivity was undetectable in developing human brain. In control human hippocampus and cortex (from young controls) only occasional GFAP+1 positive cells were observed. In contrast, GFAP+1 immunoreactivity was consistently detected in the glial component of the epileptogenic lesions. Balloon cells in FCD and giant cells in TSC, only rarely express GFAP+1. GFAP+1 co-localized with GFAPalpha, but not with GFAPdelta. Co-localization with aquaporin 4 was observed around blood vessels. GFAP+1 immunoreactivity in epilepsy-associated pathologies reveals a specific subpopulation of astrocytes in regions of astrogliosis. Further studies on GFAP+1 positive astrocytes are important to understand whether the expression of this isoform may affect the cytoskeletal integrity and the shape and function of glial cells under pathological conditions. However, while the staining is increased in epilepsy-associated pathologies, GFAP+1 is expressed in a small percentage of astrocytes. Thus, the possible role of this subpopulation of astrocytes in epilepsy is likely minor, compared to astrocytes expressing other GFAP isoforms.

Tissue plasminogen activator and urokinase plasminogen activator in human epileptogenic pathologies.

A growing body of evidence demonstrates the involvement of plasminogen activators (PAs) in a number of physiologic and pathologic events in the CNS. Induction of both tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) has been observed in different experimental models of epilepsy and tPA has been implicated in the mechanisms underlying seizure activity. We investigated the expression and the cellular distribution of tPA and uPA in several epileptogenic pathologies, including hippocampal sclerosis (HS; n=6), and developmental glioneuronal lesions, such as focal cortical dysplasia (FCD, n=6), cortical tubers in patients with the tuberous sclerosis complex (TSC; n=6) and in gangliogliomas (GG; n=6), using immuno-cytochemical, western blot and real-time quantitative PCR analysis. TPA and uPA immunostaining showed increased expression within the epileptogenic lesions compared to control specimens in both glial and neuronal cells (hippocampal neurons in HS and dysplastic neurons in FCD, TSC and GG specimens). Confocal laser scanning microscopy confirmed expression of both proteins in astrocytes and microglia, as well as in microvascular endothelium. Immunoblot demonstrated also up-regulation of the uPA receptor (uPAR; P<0.05). Increased expression of tPA, uPA, uPAR and tissue PA inhibitor type mRNA levels was also detected by PCR analysis in different epileptogenic pathologies (P<0.05). Our data support the role of PA system components in different human focal epileptogenic pathologies, which may critically influence neuronal activity, inflammatory response, as well as contributing to the complex remodeling of the neuronal networks occurring in epileptogenic lesions.

Expression and localization of voltage dependent potassium channel Kv4.2 in epilepsy associated focal lesions.

An increasing number of observations suggest an important role for voltage-gated potassium (Kv) channels in epilepsy. We studied the cell-specific distribution of Kv4.2, phosphorylated (p) Kv4.2 and the Kv4.2 interacting protein NCS-1 using immunocytochemistry in different epilepsy-associated focal lesions. In hippocampal sclerosis (HS), Kv4.2 and pKv4.2 immunoreactivity (IR) was reduced in the neuropil in regions with prominent neuronal cell loss. In both HS and malformations of cortical development (MCD), intense labeling was found in neuronal somata, but not in dendrites. Strong NCS-1 IR was observed in neurons in all lesion types. Western blot analysis demonstrated an increase of total Kv4.2 in all lesions and activation of the ERK pathway in HS and ganglioglioma. These findings indicate that Kv4.2 is expressed in both neuronal and glial cells and its regulation may involve potassium channel interacting proteins, alterations in the subcellular localization of the channel, as well as phosphorylation-mediated posttranslational modifications.

Cellular localization of metabotropic glutamate receptors in cortical tubers and subependymal giant cell tumors of tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder associated with cortical malformations (cortical tubers) and the development of glial tumors (subependymal giant-cell tumors, SGCTs). Expression of metabotropic glutamate receptor (mGluR) subtypes is developmentally regulated and several studies suggest an involvement of mGluR-mediated glutamate signaling in the regulation of proliferation and survival of neural stem-progenitor cells, as well as in the control of tumor growth. In the present study, we have investigated the expression and cell-specific distribution of group I (mGluR1, mGluR5), group II (mGluR2/3) and group III (mGluR4 and mGluR8) mGluR subtypes in human TSC specimens of both cortical tubers and SGCTs, using immunocytochemistry. Strong group I mGluR immunoreactivity (IR) was observed in the large majority of TSC specimens in dysplastic neurons and in giant cells within cortical tubers, as well as in tumor cells within SGCTs. In particular mGluR5 appeared to be most frequently expressed, whereas mGluR1alpha was detected in a subpopulation of neurons and giant cells. Cells expressing mGluR1alpha and mGluR5, demonstrate IR for phospho-S6 ribosomal protein (PS6), which is a marker of the mammalian target of rapamycin (mTOR) pathway activation. Group II and particularly group III mGluR IR was less frequently observed than group I mGluRs in dysplastic neurons and giant cells of tubers and tumor cells of SGCTs. Reactive astrocytes were mainly stained with mGluR5 and mGluR2/3. These findings expand our knowledge concerning the cellular phenotype in cortical tubers and in SGCTs and highlight the role of group I mGluRs as important mediators of glutamate signaling in TSC brain lesions. Individual mGluR subtypes may represent potential pharmacological targets for the treatment of the neurological manifestations associated with TSC brain lesions.

Acquired multiple Acyl-CoA dehydrogenase deficiency in 10 horses with atypical myopathy.

The aim of the current study was to assess lipid metabolism in horses with atypical myopathy. Urine samples from 10 cases were subjected to analysis of organic acids, glycine conjugates, and acylcarnitines revealing increased mean excretion of lactic acid, ethylmalonic acid, 2-methylsuccinic acid, butyrylglycine, (iso)valerylglycine, hexanoylglycine, free carnitine, C2-, C3-, C4-, C5-, C6-, C8-, C8:1-, C10:1-, and C10:2-carnitine as compared with 15 control horses (12 healthy and three with acute myopathy due to other causes). Analysis of plasma revealed similar results for these predominantly short-chain acylcarnitines. Furthermore, measurement of dehydrogenase activities in lateral vastus muscle from one horse with atypical myopathy indeed showed deficiencies of short-chain acyl-CoA dehydrogenase (0.66 as compared with 2.27 and 2.48 in two controls), medium-chain acyl-CoA dehydrogenase (0.36 as compared with 4.31 and 4.82 in two controls) and isovaleryl-CoA dehydrogenase (0.74 as compared with 1.43 and 1.61 nmol min(-1) mg(-1) in two controls). A deficiency of several mitochondrial dehydrogenases that utilize flavin adenine dinucleotide as cofactor including the acyl-CoA dehydrogenases of fatty acid beta-oxidation, and enzymes that degrade the CoA-esters of glutaric acid, isovaleric acid, 2-methylbutyric acid, isobutyric acid, and sarcosine was suspected in 10 out of 10 cases as the possible etiology for a highly fatal and prevalent toxic equine muscle disease similar to the combined metabolic derangements seen in human multiple acyl-CoA dehydrogenase deficiency also known as glutaric acidemia type II.

Calcinosis in juvenile dermatomyositis: a possible role for the vitamin K-dependent protein matrix Gla protein.

OBJECTIVES: The aims of the present study were to investigate whether the calcification inhibitor matrix Gla protein (MGP) is expressed in muscle biopsies of patients with juvenile dermatomyositis (JDM), and whether different forms of MGP are differentially expressed in JDM patients with and without subcutaneous calcifications. METHODS: Muscle tissue from six JDM patients (three without calcinosis, two with calcinosis and one recently diagnosed patient), four patients with muscular dystrophy, three patients with IBM and five normal histological control subjects was used for immunohistochemistry staining using novel antibodies to different conformations of MGP. RESULTS: In the JDM patients, all forms of MGP [non-carboxylated MGP (ucMGP), carboxylated MGP (cMGP), non-phosphorylated MGP (serMGP) and phosphorylated MGP (pserMGP)] were more intensely stained in the perifascicular compared with the central muscle fibres. In addition, these MGP species were demonstrated in the pathological muscle fibres of IBM and dystrophy patients, but hardly in normal histological muscle tissue. In JDM patients with calcifications, only pserMGP was increased compared with those without calcifications. All forms of MGP were also found in various staining intensities in the microvasculature and macrophages of normal histological and disease biopsies. CONCLUSIONS: MGP was expressed at the site of muscle damage in JDM patients as well as in patients with muscular dystrophy and IBM. The difference in staining intensity of pserMGP appeared to distinguish between JDM patients with and without calcifications, whereas cMGP, the other functional form, was equally expressed.

Gene expression profile analysis of epilepsy-associated gangliogliomas.

Gangliogliomas (GG) constitute the most frequent tumor entity in young patients undergoing surgery for intractable epilepsy. The histological composition of GG, with the presence of dysplastic neurons, corroborates their maldevelopmental origin. However, their histogenesis, the pathogenetic relationship with other developmental lesions, and the molecular alterations underlying the epileptogenicity of these tumors remain largely unknown. We performed gene expression analysis using the Affymetrix Gene Chip System (U133 plus 2.0 array). We used GENMAPP and the Gene Ontology database to identify global trends in gene expression data. Our analysis has identified various interesting genes and processes that are differentially expressed in GG when compared with normal tissue. The immune and inflammatory responses were the most prominent processes expressed in GG. Several genes involved in the complement pathway displayed a high level of expression compared with control expression levels. Higher expression was also observed for genes involved in cell adhesion, extracellular matrix and proliferation processes. We observed differential expression of genes as cyclin D1 and cyclin-dependent kinases, essential for neuronal cell cycle regulation and differentiation. Synaptic transmission, including GABA receptor signaling was an under-expressed process compared with control tissue. These data provide some suggestions for the molecular pathogenesis of GG. Furthermore, they indicate possible targets that may be investigated in order to dissect the mechanisms of epileptogenesis and possibly counteract the epileptogenic process in these developmental lesions.

Common ("classical") and covered cloacal exstrophy: a histopathological study and a reconstruction of the pathogenesis.

Current opinion about structure and pathogenesis of cloacal exstrophy was challenged by histopathological findings and new insights into the normal development. Autopsy specimens of common (n = 3) and covered cloacal exstrophy (n = 4) with single intraexstrophic and -perineal phallic structures and perineo-exstrophic canals have been analyzed histopathologically. The findings were correlated to normal development to reconstruct the pathogenesis. By identifying a specific cloaca-derived urethra field as distinct from allantois-derived bladder fields, the exstrophic area is found to reflect the original hindgut configuration in embryos of approximately 26-29 postovulatory days gestational age (2-4 mm). Correlation to normal development suggests malfunctioning of the primitive streak/caudal eminence as a primary fault that leads to a defective cloacal region in the hindgut disturbing cloacal-intestinal-allantoic dissociation and also causes lengthening of the intestinal region into a blind-ending colon, teratoma-like lesions, and vertebral and muscular anomalies. The current idea that membranes in "covered cloacal exstrophy" represent persisting cloacal membranes is dismissed by finding an amnion-like structure, which suggests dysfunction of an umbilical ring placode as a simultaneous 2nd fault. This malfunctioning may cause omphalocele by defective demarcation of the umbilical cord and may replace midline stroma of the infraumbilical abdominal wall by extraembryonic tissue that stretches into a weak temporary membrane, may leave a perineo-extrophic canal, and may allow the formation of a single perineal or intraexstrophic phallus. Malfunctioning without replacement may result in a purely epithelial "allantoic" membrane, which by disintegrating in combination with the cloacal membrane will expose common cloacal exstrophy.

Inflammatory processes in cortical tubers and subependymal giant cell tumors of tuberous sclerosis complex.

Cortical tubers and subependymal giant cell tumors (SGCT) are two major cerebral lesions associated with tuberous sclerosis complex (TSC). In the present study, we investigated immunocytochemically the inflammatory cell components and the induction of two major pro-inflammatory pathways (the interleukin (IL)-1beta and complement pathways) in tubers and SGCT resected from TSC patients. All lesions were characterized by the prominent presence of microglial cells expressing class II-antigens (HLA-DR) and, to a lesser extent, the presence of CD68-positive macrophages. We also observed perivascular and parenchymal T lymphocytes (CD3(+)) with a predominance of CD8(+) T-cytotoxic/suppressor lymphoid cells. Activated microglia and reactive astrocytes expressed IL-1beta and its signaling receptor IL-1RI, as well as components of the complement cascade, such as C1q, C3c and C3d. Albumin extravasation, with uptake in astrocytes, was observed in both tubers and SGCT, suggesting that alterations in blood brain barrier permeability are associated with inflammation in TSC-associated lesions. Our findings demonstrate a persistent and complex activation of inflammatory pathways in cortical tubers and SGCT.

A neuropathological study of two autopsy cases of syndromic hemimegalencephaly.

Hemimegalencephaly (HMEG) is a malformation of cortical development characterized by unilateral enlargement of the cerebral hemisphere, severe architectural and cellular abnormalities and association with intractable epilepsy. HMEG may represent an isolated lesion of the central nervous system, but may also be associated with several neurocutaneous syndromes. In the present study we discuss the neuropathological findings of two autopsy cases of HMEG associated with linear naevus sebaceous syndrome. Both cases showed the presence of linear naevus sebaceous on extensive areas of the face. The neurochemical profile of the glial and neuronal components in the affected hemisphere was determined using immunocytochemical markers and was compared with the unaffected contralateral hemisphere and normal control tissue. The observed cytomegalic neurones expressed receptors for distinct neurotransmitters, neuropeptides and growth factors. Analysis of components of the phosphoinositide 3-kinase pathway revealed expression of phospho-S6 ribosomal protein in cytomegalic neurones. Autopsy findings confirm the complexity of the histologic phenotypic manifestations in HMEG and proved useful in determining the spectrum of cytoarchitectural and neurochemical abnormalities, underlying the molecular pathogenesis and epileptogenesis of this brain malformation.

Complement activation in experimental and human temporal lobe epilepsy.

We investigated the involvement of the complement cascade during epileptogenesis in a rat model of temporal lobe epilepsy (TLE), and in the chronic epileptic phase in both experimental as well as human TLE. Previous rat gene expression analysis using microarrays indicated prominent activation of the classical complement pathway which peaked at 1 week after SE in CA3 and entorhinal cortex. Increased expression of C1q, C3 and C4 was confirmed in CA3 tissue using quantitative PCR at 1 day, 1 week and 3-4 months after status epilepticus (SE). Upregulation of C1q and C3d protein expression was confirmed mainly to be present in microglia and in a few hippocampal neurons. In human TLE with hippocampal sclerosis, astroglial, microglial and neuronal (5/8 cases) expression of C1q, C3c and C3d was observed particularly within regions where neuronal cell loss occurs. The membrane attack protein complex (C5b-C9) was predominantly detected in activated microglial cells. The persistence of complement activation could contribute to a sustained inflammatory response and could destabilize neuronal networks involved.

Inhibitory networks in epilepsy-associated gangliogliomas and in the perilesional epileptic cortex.

Developmental glioneuronal lesions, such as gangliogliomas (GG) are increasingly recognized causes of chronic pharmaco-resistant epilepsy. It has been postulated that chronic epilepsy in patients with malformations of cortical development is associated with dysfunction of the inhibitory GABA-ergic system. We aimed to identify the subtypes of interneurons present within GG specimens and the expression and cellular distribution patterns of GABA receptors (GABAR) and GABA transporter 1 (GAT1). The expression of the various components of the GABA-ergic system were also analyzed in the perilesional cortex. We investigated the expression of parvalbumin, calbindin, calretinin, GABA(A)R (a1 subunit)(,) GABA(B) (R1 and R2) and GAT-1 using immunocytochemistry in 30 specimens of GG obtained during epilepsy surgery, including 10 cases with sufficient amount of perilesional cortex. Immunocytochemistry for calbindin (CB), calretinin (CR) and parvalbumin (PV) demonstrate the presence of inhibitory neurons of different subtypes within the GG specimens. Calcium-binding protein-positive interneurons represent a small fraction of the total neuronal population. Both GABA(A)R and GABA(B)R (R1 and R2) subtypes were detected within the neuronal component of GG specimens. In addition, GABA(B)R2 immunoreactivity (IR) was observed in glial cells. GG specimens displayed also expression of GAT-1 IR. Compared to normal cortex, the density of PV- and CB-immunoreactive interneurons was reduced in the perilesional cortex of GG patients, whereas CR-labeling was similar to that observed in normal cortex. GAT-1 IR was also significantly reduced in the perilesional specimens. The cellular distribution of components of the GABA-ergic system in GG, together with the perilesional changes suggest that alterations of the GABA-ergic system may contribute to the complex abnormal functional network of these highly epileptogenic developmental lesions.