Cortical expression of IL1-ß, Bcl-2, Caspase-3 and 9, SEMA-3a, NT-3 and P-glycoprotein as biological markers of intrinsic severity in drug-resistant temporal lobe epilepsy.

Mesial temporal lobe epilepsy (mTLE) is the most common epilepsy induced by previous cerebral injury, and one out of three mTLE patients develops drug resistance (DR). AIM: To assess the expression of Bcl-2, Caspase-3, Caspase-9, IL1-ß, SEMA-3a, NT-3 and P-glycoprotein in the temporal cortex and their relationship with the progression of mTLE-DR clinical features in patients with mTLE-DR. METHOD: Tissue samples from 17 patients were evaluated for protein expression by Western blot and the relationships of the evaluated proteins with the clinical features of the mTLE were assessed through hierarchical cluster analysis. RESULTS: The mTLE-DR group showed significantly higher P-glycoprotein, Bcl-2 and Caspase-9 levels ***p < 0.0001, ****p < 0.0001 and ***p < 0.0002, respectively, than the autopsy control group. Four patient clusters were identified: Clusters 1 and 3 showed relationships among the age of mTLE onset, duration of mTLE-DR, average number of epileptic seizures per week, number of previous antiepileptic drugs (AEDs) and increased expression of Caspase-3, Caspase-9, Neurotrophin-3 and Semaphorin-3a. Clusters 2 and 4 showed relationships among the mTLE onset age, current age, average number of epileptic seizures per week, number of previous AEDs and increased expression of IL1-ß, Bcl-2, P-glycoprotein, Caspase-3 and NT-3. CONCLUSION: The relationships among the clinical data the age of mTLE onset, DR duration, number of previous AEDs, and average number of seizures per week and the expression of proteins involved in neuronal death, neuroinflammation and aberrant connection formation, as which are biological markers in the cerebral temporal cortex, are important factors in the progression and severity of mTLE-DR and support the intrinsic severity hypothesis.

Increased Expression of Brain-Derived Neurotrophic Factor Transcripts I and VI, cAMP Response Element Binding, and Glucocorticoid Receptor in the Cortex of Patients with Temporal Lobe Epilepsy.

A body of evidence supports a relevant role of brain-derived neurotrophic factor (BDNF) in temporal lobe epilepsy (TLE). Magnetic resonance data reveal that the cerebral atrophy extends to regions that are functionally and anatomically connected with the hippocampus, especially the temporal cortex. We previously reported an increased expression of BDNF messenger for the exon VI in the hippocampus of temporal lobe epilepsy patients compared to an autopsy control group. Altered levels of this particular transcript were also associated with pre-surgical use of certain psychotropic. We extended here our analysis of transcripts I, II, IV, and VI to the temporal cortex since this cerebral region holds intrinsic communication with the hippocampus and is structurally affected in patients with TLE. We also assayed the cyclic adenosine monophosphate response element-binding (CREB) and glucocorticoid receptor (GR) genes as there is experimental evidence of changes in their expression associated with BDNF and epilepsy. TLE and pre-surgical pharmacological treatment were considered as the primary clinical independent variables. Transcripts BDNF I and BDNF VI increased in the temporal cortex of patients with pharmacoresistant TLE. The expression of CREB and GR expression follow the same direction. Pre-surgical use of selective serotonin reuptake inhibitors, carbamazepine (CBZ) and valproate (VPA), was associated with the differential expression of specific BDNF transcripts and CREB and GR genes. These changes could have functional implication in the plasticity mechanisms related to temporal lobe epilepsy.

Increased expression of BDNF transcript with exon VI in hippocampi of patients with pharmaco-resistant temporal lobe epilepsy.

A putative role of the brain-derived neurotrophic factor (BDNF) in epilepsy has emerged from in vitro and animal models, but few studies have analyzed human samples. We assessed the BDNF expression of transcripts with exons I (BDNFI), II (BDNFII), IV (BDNFIV) and VI (BDNFVI) and methylation levels of promoters 4 and 6 in the hippocampi of patients with pharmaco-resistant temporal lobe epilepsy (TLE) (n=24). Hippocampal sclerosis (HS) and pre-surgical pharmacological treatment were considered as clinical independent variables. A statistical significant increase for the BDNFVI (p<0.05) was observed in TLE patients compared to the autopsy control group (n=8). BDNFVI was also increased in anxiety/depression TLE (N=4) when compared to autopsies or to the remaining group of patients (p<0.05). In contrast, the use of the antiepileptic drug Topiramate (TPM) (N=3) was associated to a decrease in BDNFVI expression (p<0.05) when compared to the remaining group of patients. Methylation levels at the BDNF promoters 4 and 6 were similar between TLE and autopsies and in relation to the use of either Sertraline (SRT) or TPM. These results suggest an up-regulated expression of a specific BDNF transcript in patients with TLE, an effect that seems to be dependent on the use of specific drugs.

Cellular damage markers in the temporal lobe of a patient with Dyke-Davidoff-Masson Syndrome.

We studied the cellular damage in a patient with Dyke-Davidoff-Masson Syndrome and a history of chronic temporal lobe epilepsy resistant to treatment. The epileptogenic zone was localized to the right temporal lobe, and an extensive surgical removal of the temporal neocortex plus amygdala and hippocampus was performed. The specimens were immediately frozen in liquid nitrogen and stored at -75 degrees C for biochemical studies. Specimens were immersed and fixed in freshly prepared 4% paraformaldehyde for histopathological evaluation. Neurotransmitter levels were highest in the hippocampus compared to the temporal neocortex (T1, T2, and T3). In the amygdala, GABA was found whereas other amino acids were absent. We found marked dislamination in all areas of the cortex, neuronal loss, amylaceous bodies, and neuronal cytomegaly with cytoskeletal disorganization containing dense fibrillar cytoplasmic aggregates, nodular heterotopias, dysplastic and large neurons with high Nissl staining, intermixed with balloon cells with atypical nuclei, often with binucleation, and abundant glassy eosinophilic cytoplasm. Positive immunoreactive cells with nestin, vimentin, and enhanced expression of astrocytes were observed in all brain regions. This patient's syndrome should be considered as a postinfectious/post-stroke event that caused hemiparesis and later recurrent seizures. Higher expression of nestin and vimentin has been observed in proliferative neuronal cells, the expression in astrocytes may mainly reflect an early response of these cells to injury. Nestin may play a role in protecting the brain from injury. It has been proposed that re-expression of embryonic genes by mature cells is associated with morphological plasticity.

Corpus callosotomy using conformal stereotactic radiosurgery.

OBJECTS: To show the clinical results of a corpus callosotomy (CC) treatment using conformal stereotactic radiosurgery (SRS) on a patient with medically intractable multifocal epilepsy. MATERIALS AND METHODS: A 17-year-old male patient underwent corpus callosotomy conformal SRS using a dedicated linear accelerator (linac) with dynamic arcs technique. The prescribed dose was 36.0 Gy at the periphery of the rostrum, genu, and a half of the body of the corpus callosum (CCA). At 8 months after conformal SRS, the patient developed a significant brain edema and moderate transitory motor deficit, which were controlled with steroids. After 32 months follow-up, there is an improvement of 84% on drop attacks and generalized tonic-clonic seizures. CONCLUSIONS: Conformal SRS for corpus callosotomy with a single isocenter reproduce the results reported on literature using Gamma Knife-based SRS. The results show that this technique is safe and demonstrate its efficacy to control seizures.

Evidence that brain-derived neurotrophic factor from presynaptic nerve terminals regulates the phenotype of calbindin-containing neurons in the lateral septum.

Brain-derived neurotrophic factor (BDNF) is transported anterogradely in neurons of the CNS and can be released by activity-dependent mechanisms to regulate synaptic plasticity. However, few neural networks have been identified in which the production, transport, and effects of BDNF on postsynaptic neurons can be analyzed in detail. In this study, we have identified such a network. BDNF has been colocalized by immunocytochemistry with tyrosine hydroxylase (TH) in nerve fibers and nerve terminals within the lateral septum of rats. BDNF-containing nerve fibers terminate on a population of calbindin-containing neurons in lateral septum that contain TrkB, the high-affinity receptor for BDNF. Overexpression of BDNF in noradrenergic neurons increased levels of calbindin in septum, as well as in whole-brain lysates. Septal levels of calbindin and BDNF partially decreased after unilateral lesions of the medial forebrain bundle (MFB), induced with 6-hydroxydopamine, a treatment that abolished TH staining. These data suggest that BDNF is anterogradely transported within the MFB in catecholaminergic neurons arising from brainstem nuclei. To determine whether BDNF affects the production of calbindin in lateral septal neurons directly, we tested the effects of BDNF on cultures of septal neurons from embryonic day 16-17 rats. BDNF promoted the expression of calbindin, as well as the arborization of calbindin-containing neurons, but BDNF had no effect on cell division or survival. Together, these results suggest that BDNF, anterogradely transported in catecholaminergic neurons, regulates calbindin expression within the lateral septum.

Characterization of dopaminergic midbrain neurons in a DBH:BDNF transgenic mouse.

The neurotrophin brain-derived neurotrophic factor (BDNF) has been implicated in the survival and differentiation of central nervous system neurons, including dopaminergic cells in culture. To determine whether BDNF might play a role in the development of dopaminergic neurons in vivo, we used a previously characterized transgenic mouse (DBH:BDNF) that overexpresses BDNF in adrenergic and noradrenergic neurons as a result of fusion of the BDNF gene to the dopamine beta-hydroxylase (DBH) gene promoter. We quantified dopaminergic neuronal profiles at four midbrain coronal levels and compared DBH:BDNF transgenic animals with wild-type mice of the same genetic background. Analysis of sections immunostained with tyrosine hydroxylase (TH) showed that the mean number of dopaminergic neurons in the four selected midbrain sections was 52% greater (one-way analysis of variance, P < 0.0005) in transgenic mice (2,165 +/- 55 S. E.M., n = 4) than in control mice (1,428 +/- 71 S.E.M., n = 4). The increase in dopaminergic neuron profile count in DBH:BDNF transgenic animals was confirmed by analysis of the pars compacta of the substantia nigra on Nissl-stained sections. Surface area of the reference region of interest containing TH-immunoreactive neurons was similar in transgenic and control mice. Regional analysis of different midbrain areas containing dopaminergic neurons suggested that the increase in cell profile count occurs in a relatively homogeneous manner. Comparison of TH-immunoreactive cell size showed a tendency for smaller neurons in transgenic animals, but the difference was not statistically significant. We conclude that DBH:BDNF transgenic mice show increased number of TH-immunoreactive cells in the midbrain. We propose that BDNF rescues dopaminergic neurons from the perinatal period of developmental cell death as a consequence of increased anterograde transport of the neurotrophin via the coeruleonigral projection.

Topographic analysis of the gyral patterns of the central area.

Great advances in imaging technology allows the surgeon to visualize the entire brain surface during surgery. However, the cerebral convolutions are extremely complex, so that it is often difficult to define the central area precisely. Using the curvilinear reconstruction technique (Gyroview) and MRI, we have analyzed the gyral anatomy of the central area in 20 normal brans and have recognized several patterns of topographic organization and have classified them into several categories. We divided the central area into anterior and posterior subregions with the central sulcus as the main landmark. More specifically, we studied how the pre- and postcentral gyri merge into the frontal and parietal lobe proper by anatomical bridges (roots). We describe three anterior and two main posterior roots which originate from the precentral and the postcentral gyrus, respectively. We found four different types of pattern for the anterior roots and as many as 10 different patterns for the posterior roots. The arterior roots are relatively constant, compared to the posterior ones. The most frequent pattern (type 1) was found in 33 hemispheres among the 40 analyzed (82.5%). Four main posterior root patterns were recognized in 32 hemispheres of the 40 analyzed (80%). Thus, although gyral variability was encountered for the posterior roots, a very constant global pattern was seen for the central area. One of the most important steps of frameless stereotactic-guided epilepsy surgery is the precise localization of the central area. Therefore, a knowledge of gyral patterns of the central area is essential not only for the resective epilepsy surgery, but also for the successful removal of a variety of lesions in the central area.

The immunosuppressant FK506 prolongs transgene expression in brain following adenovirus-mediated gene transfer.

First generation, replication-defective adenoviral vectors are highly effective for gene transfer into the central nervous system, but the host's immune response limits the utility of this vector for possible therapy of neurological disease or long-term gene transfer studies in experimental animals. We have demonstrated the effectiveness of FK506 (tacrolimus), a powerful immunosuppressant that readily crosses the blood-brain barrier, in maintaining adenovirus-mediated reporter gene transfer following stereotaxic injection of the recombinant (AdCMVlacZ) into mouse striatum. After 28 days, beta-galactosidase expression was reduced by 75% relative to day 10 in immunocompetent animals, accompanied by an inflammatory reaction in the region of transduced cells; however, in mice receiving daily s.c. injections of FK506, beta-galactosidase activity was maintained at the 10 days post-injection level.