Epileptogenesis and drug-resistant in focal cortical dysplasias: Update on clinical, cellular, and molecular markers.

Focal cortical dysplasia (FCD) is a cortical malformation in brain development and is considered as one of the major causes of drug-resistant epilepsiesin children and adults. The pathogenesis of FCD is yet to be fully understood. Imaging markers such as MRI are currently the surgeons major obstacle due to the difficulty in delimiting the precise dysplasic area and a mosaic brain where there is epileptogenic tissue invisible to MRI. Also increased gene expression and activity may be responsible for the alterations in cell proliferation, migration, growth, and survival. Altered expressions were found, particularly in the PI3K/AKT/mTOR pathway. Surgery is still considered the most effective treatment option, due to drug-resistance, and up to 60 % of patients experience complete seizure control, varying according to the type and location of FCD. Both genetic and epigenetic factors may be involved in the pathogenesis of FCD, and there is no conclusive evidence whether these alterations are inherited or have an environmental origin.

Drebrin expression patterns in patients with refractory temporal lobe epilepsy and hippocampal sclerosis.

OBJECTIVE: Drebrins are crucial for synaptic function and dendritic spine development, remodeling, and maintenance. In temporal lobe epilepsy (TLE) patients, a significant hippocampal synaptic reorganization occurs, and synaptic reorganization has been associated with hippocampal hyperexcitability. This study aimed to evaluate, in TLE patients, the hippocampal expression of drebrin using immunohistochemistry with DAS2 or M2F6 antibodies that recognize adult (drebrin A) or adult and embryonic (pan-drebrin) isoforms, respectively. METHODS: Hippocampal sections from drug-resistant TLE patients with hippocampal sclerosis (HS; TLE, n = 33), of whom 31 presented with type 1 HS and two with type 2 HS, and autopsy control cases (n = 20) were assayed by immunohistochemistry and evaluated for neuron density, and drebrin A and pan-drebrin expression. Double-labeling immunofluorescences were performed to localize drebrin A-positive spines in dendrites (MAP2), and to evaluate whether drebrin colocalizes with inhibitory (GAD65) and excitatory (VGlut1) presynaptic markers. RESULTS: Compared to controls, TLE patients had increased pan-drebrin in all hippocampal subfields and increased drebrin A-immunopositive area in all hippocampal subfields but CA1. Drebrin-positive spine density followed the same pattern as total drebrin quantification. Confocal microscopy indicated juxtaposition of drebrin-positive spines with VGlut1-positive puncta, but not with GAD65-positive puncta. Drebrin expression in the dentate gyrus of TLE cases was associated negatively with seizure frequency and positively with verbal memory. TLE patients with lower drebrin-immunopositive area in inner molecular layer (IML) than in outer molecular layer (OML) had a lower seizure frequency than those with higher or comparable drebrin-immunopositive area in IML compared with OML. SIGNIFICANCE: Our results suggest that changes in drebrin-positive spines and drebrin expression in the dentate gyrus of TLE patients are associated with lower seizure frequency, more preserved verbal memory, and a better postsurgical outcome.

Nociceptin/orphanin FQ receptor modulates painful and fatigue symptoms in a mouse model of fibromyalgia.

Generalized pain and fatigue are both hallmarks of fibromyalgia, a syndrome with an indefinite etiology. The treatment options for fibromyalgia are currently limited, probably because of its intricate pathophysiology. Thus, further basic and clinical research on this condition is currently needed. This study investigated the effects of nociceptin/orphanin FQ (N/OFQ) receptor (NOPr) ligands and the modulation of the NOP system in the preclinical mouse model of reserpine-induced fibromyalgia. The effects of administration of the natural agonist N/OFQ and the selective NOPr antagonists (UFP-101 and SB-612111) were evaluated in fibromyalgia-related symptoms in reserpine-treated mice. The expression of prepronociceptin/orphanin FQ and NOPr was assessed in central and peripheral sites at different time points after reserpine administration. Nociceptin/orphanin FQ displayed dual effects in the behavioral changes in the reserpine-elicited fibromyalgia model. The peptide NOPr antagonist UFP-101 produced analgesic and antifatigue effects, by preventing alterations in brain activity and skeletal muscle metabolism, secondary to fibromyalgia induction. The nonpeptide NOPr antagonist SB-612111 mirrored the favorable effects of UFP-101 in painful and fatigue alterations induced by reserpine. A time-related up- or downregulation of prepronociceptin/orphanin FQ and NOPr was observed in supraspinal, spinal, and peripheral sites of reserpine-treated mice. Our data shed new lights on the mechanisms underlying the fibromyalgia pathogenesis, supporting a role for N/OFQ-NOP receptor system in this syndrome.

An 18-year follow-up of seizure outcome after surgery for temporal lobe epilepsy and hippocampal sclerosis.

OBJECTIVES: To evaluate the very long-term clinical outcome of surgery for mesial temporal lobe epilepsy and unilateral hippocampal sclerosis (MTLE/HS) without atypical features. The impact of surgical technique and postoperative reduction of medication on this outcome was investigated. DESIGN: Prospective longitudinal cohort follow-up study for up to18 years. SETTING: Epilepsy surgery centre in a university hospital. PATIENTS: 108 patients who underwent unilateral MTLE/HS. INTERVENTION: Surgery for MTLE/HS. MAIN OUTCOME MEASURE: Engel classification (I). Clinical evaluations were based on systematic interviews in person or by phone. Kaplan-Maier survival curves estimated the probability of remaining seizure free. The impact of medication management in the postoperative outcome was analysed using Cox regression. RESULTS: The probability of remaining completely seizure-free at 12 and 18 years after MTLE/HS surgery was 65% and 62%, respectively. The risk of having any recurrence was 22% during the first 24 months and increased 1.4% per year afterwards. Type of surgical technique (selective amygdalohippocampectomy vs anterior temporal lobectomy) did not impact on outcome. Remaining on antiepileptic drugs and history of generalised clonic seizure diminished the probability of remaining seizure free. CONCLUSIONS: MTLE/HS surgery is able to keep patients seizure free for almost up to two decades. Removal of the neocortex besides the mesial portion of the temporal lobe does not lead to better chances of seizure control. These findings are applicable to the typical unilateral MTLE/HS syndrome and cannot be generalised for all types of TLE. Future longitudinal randomised controlled studies are needed to replicate these findings.

Subcortical band heterotopia (SBH) in males: clinical, imaging and genetic findings in comparison with females.

Subcortical band heterotopia (SBH) or double cortex syndrome is a neuronal migration disorder, which occurs very rarely in males: to date, at least 110 females but only 11 in males have been reported. The syndrome is usually associated with mutations in the doublecortin (DCX) (Xq22.3-q23) gene, and much less frequently in the LIS1 (17p13.3) gene. To determine whether the phenotypic spectrum, the genetic basis and genotype-phenotype correlations of SBH in males are similar to those in females, we compared the clinical, imaging and molecular features in 30 personally evaluated males and 60 previously reported females with SBH. Based on the MRI findings, we defined the following band subtypes: partial, involving one or two cerebral lobes; intermediate, involving two lobes and a portion of a third; diffuse, with substantial involvement of three or more lobes; and pachygyria-SBH, in which posterior SBH merges with anterior pachygyria. Karyo typing and mutation analysis of DCX and/or LIS1 were performed in 23 and 24 patients, respectively. The range of clinical phenotypes in males with SBH greatly overlapped that in females. MRI studies revealed that some anatomical subtypes of SBH, such as partial and intermediate posterior, pachygyria-SBH and diffuse bands with posterior predominance, were more frequently or exclusively present in males. Conversely, classical diffuse SBH and diffuse bands with anterior predominance were more frequent in females. Males had either mild or the most severe band subtypes, and these correlated with the over-representation of normal/borderline intelligence and severe mental retardation, respectively. Conversely, females who had predominantly diffuse bands exhibited mostly mild or moderate mental retardation. Seven patients (29%) had missense mutations in DCX; in four, these were germline mutations, whereas in three there was evidence for somatic mosaicism. A germline missense mutation of LIS1 and a partial trisomy of chromosome 9p were identified in one patient (4%) each. One male each had a possible pathogenic intronic base change in both DCX and LIS1 genes. Our study shows that SBH in males is a clinically heterogeneous syndrome, mostly occurring sporadically. The clinical spectrum is similar to that of females with SBH. However, the greater cognitive and neuroradiological heterogeneity and the small number of mutations identified to date in the coding sequences of the DCX and LIS1 genes in males differ from the findings in females. This suggests other genetic mechanisms such as mutations in the non-coding regions of the DCX or LIS1 genes, gonadal or somatic mosaicism, and finally mutations of other genes.