Zheng Xiao

Increased Expression of DNA methyltransferase 1 and 3a in Human Temporal Lobe Epilepsy

DNA methylation is a key epigenetic modification of DNA that is catalyzed by DNA methyltransferase (DNMT). Increasing evidence suggests that DNA methylation in neurons regulates synaptic plasticity as well as neuronal network activity. Here, we evaluated DNA methyltransferase 1 (Dnmt1) and Dnmt3a expression in brain tissues of epileptic patients to explore their possible role in epileptogenesis. Tissue samples from temporal neocortices of 25 patients with intractable temporal lobe epilepsy (TLE) and ten histologically normal temporal lobes from control patients were used to detect Dnmt1 and Dnmt3a expression through immunohistochemistry, immunofluorescence, and Western blotting analysis. We found that both Dnmt1 and Dnmt3a expression were principally expressed in the nucleus and the cytoplasm of NeuN-positive neurons, but not in GFAP-positive astrocytes. Levels of the two DNMT proteins were significantly increased in patients with TLE. Our study suggests that DNMT1 and DNMT3a may play a role in the pathogenesis of TLE.

Proteomic analysis of cerebrospinal fluid from patients with idiopathic temporal lobe epilepsy.

Proteomic analysis of cerebrospinal fluid (CSF) from patients with temporal lobe epilepsy (TLE) and controls was carried out using two-dimensional gel electrophoresis followed by liquid chromatography electrospray ionization tandem mass spectrometry. Five protein spots showed significant differential expression (p<0.05): vitamin D-binding protein (DBP) was elevated in the CSF of TLE patients whereas cathepsin D, apolipoprotein J, Fam3c, and superoxide dismutase 1 (SOD1) were decreased in the CSF of TLE patients. Additional six protein spots presented only in the CSF of epilepsy patients were identified as tetranectin (TN), talin-2, apolipoprotein E, immunoglobulin lambda light chain (IGL@), immunoglobulin kappa variable light chain 1-5 (IGKV1-5), and procollagen C-endopeptidase enhancer 1 (PCOLCE). Expression of DBP, SOD1 and talin-2 was validated by western blot. Our results may provide better understanding of the pathophysiologic mechanisms underlying epileptogenesis and possible epilepsy biomarkers.

Down-regulation Synaptic Vesicle Protein 2A in the Anterior Temporal Neocortex of Patients with Intractable Epilepsy

Synaptic vesicle protein 2A (SV2A) involvement has been reported in the animal models of epilepsy. The aim of this study was to investigate the expression of SV2A in human intractable epilepsy (IE) brain tissue. Using immunohistochemistry, immunofluorescence, and Western blot, we detected SV2A expression in tissue samples from the anterior temporal neocortex of 33 patients who had been surgically treated for IE. We compared these tissues with nine histologically normal anterior temporal lobe samples from controls. SV2A immunoreactive staining was 0.1651 ± 0.0564 in patient group and 0.2347 ± 0.0187 in the control group (p < 0.05) using immunohistochemistry, and this finding was consistently observed with Western blot analysis (0.1727 ± 0.0471 versus 0.3976 ± 0.0983, p < 0.05). Immunofluorescence staining showed that SV2A was mainly accumulated in neurons. Our findings demonstrate that down-regulation of SV2A is present in patients with temporal lobe epilepsy.

Efficacy and Safety of Levetiracetam (3,000 mg/Day) as an Adjunctive Therapy in Chinese Patients with Refractory Partial Seizures

Aim: To evaluate the efficacy and safety of 3,000 mg daily levetiracetam (LEV; Keppra) as an adjunctive therapy for Chinese patients with refractory partial seizures. Methods: This randomized, placebo-controlled trial consisted of an 8-week baseline period followed by a 4-week titration interval and a 12-week maintenance period, and concluded with a 4-week medication withdrawal period or entered an open-label study. LEV was compared with placebo. Results: The 50% responder rate (the proportion of patients with a minimum of 50% reduction in partial seizure frequency) occurred in 46.4% of the LEV group, compared with 39.3% of the placebo group (p = 0.590). The median of the absolute weekly frequency reduction from baseline of partial seizures was 0.66 per week for LEV versus 0.48 per week for placebo (p = 0.187). The most common treatment-emergent adverse events, mostly mild to moderate in severity, were somnolence, dizziness and agitation. Conclusion: In this study, adjunctive therapy with LEV 3,000 mg daily was well tolerated but not as effective as expected in controlling partial seizures in this study population. Considering the lower mean weight of this study population, we suggest the dosage of LEV 3,000 mg daily may contribute to the results.

Downregulation of Gephyrin in Temporal Lobe Epilepsy Neurons in Humans and a Rat Model

Gephyrin, which is a postsynaptic scaffolding protein participated in clustering GABAA receptors at inhibitory synapses, has been reported to be involved in temporal lobe epilepsy (TLE) recently. Here, we investigate gephyrin protein expression in the temporal lobe epileptic foci in epileptic patients and experimental animals in order to explore the probable relationship between gephyrin expression and TLE. Using immunohistochemistry, immunofluorescence, and western blot analysis, gephyrin expression was examined in 30 human temporal neocortex samples from patients who underwent surgery to treat drug‐refractory TLE and 10 histological normal temporal neocortex from the controls. Meanwhile, we investigated the gephyrin expression in the hippocampus and adjacent neocortex from experimental rats on 24 h, 48 h, 1 week, 2 weeks, 1 month, and 2 months postseizure and from control rats. Gephyrin protein was mainly expressed in the membrane and cytoplasm of neurons in temporal lobe epileptic foci in humans and experimental rats. Gephyrin expression was significantly lower in the temporal neocortex of TLE patients compared to the controls. In experimental rats, the expression of gephyrin in temporal lobe was downregulated in epileptic groups compared to the control group. Gephyrin expression gradually decreased during the acute period and the latent period, but then began to increase below the levels seen in controls during the chronic phase. Our findings suggest that gephyrin may be involved in the development of TLE. Synapse, 2011.

Efficacy and Safety of Adjunctive Zonisamide in Adult Patients with Refractory Partial-Onset Epilepsy: A Randomized, Double-Blind, Placebo-Controlled Trial

AbstractBackground and Objective: Clinical studies have reported that zonisamide is effective for a wide range of seizure types, including refractory partial-onset seizures. However, there have been no reported studies of the efficacy of zonisamide in the Chinese population to date. The aim of the present study was to evaluate the efficacy and safety of zonisamide in the treatment of adult Chinese patients with refractory partial-onset epilepsy. Methods: This was a randomized, double-blind, placebo-controlled trial conducted over a 16-week period. 104 patients with refractory partial-onset epilepsy were enrolled. Participants were randomly assigned to receive addon zonisamide or placebo. Zonisamide was titrated to a target dosage of 300 or 400 mg/day. Seizure frequency and adverse effects were documented. Results: 102 patients completed the trial. Zonisamide showed significantly greater efficacy compared with placebo (responder rate 55.8% vs 36.0%, p < 0.05), including 55.2% (16 of 29 patients) in the zonisamide 300 mg/day arm and 56.5% (13 of 23 patients) in the zonisamide 400 mg/day arm. Zonisamide 300 and 400 mg/day showed similar efficacy (p > 0.05). Moreover, similar efficacy of zonisamide was found in the control of complex partial seizures, simple partial seizures and secondary generalized seizures. There was no difference in the incidence of adverse effects between zonisamide and placebo. Reported adverse effects in the zonisamide group involved the digestive system (32.5% of total adverse effects in the group) [including transient increases in liver enzymes (27.8%)], weight changes (30.2%), the haematological system (15.1%), neurological/psychiatric effects (10.3%), the urinary system (7.9%) and the cardiovascular system (4.0%). Only digestive system adverse effects constituted a significantly higher proportion of adverse effects in the zonisamide group than in the placebo group (32.5% vs 30.2%, p < 0.05). Conclusion: Zonisamide 300–400 mg/day is effective and well tolerated as an adjunctive drug in adult Chinese patients with refractory partial-onset epilepsy.

Increased expression of TGFβ type I receptor in brain tissues of patients with temporal lobe epilepsy

TbetaRs (transforming growth factor beta receptors) have recently been identified in animal experiments as being involved in the pathogenesis of epilepsy. The aim of the present study was to understand further the potential effects of TbetaRs in human epilepsy. Tissue samples of temporal neocortices from 30 patients with temporal lobe epilepsy were prepared for detecting TbetaR-I (type 1 TbetaR) protein expression using immunohistochemistry, immunofluorescence and Western blotting. We compared these tissues with histologically normal temporal lobes from controls. TbetaR-I immunoreactivity was increased in the patient group compared with controls using immunohistochemistry, and this finding was consistently observed with Western blot analysis. Immunofluorescence showed that TbetaR-I fluorescence stain mainly accumulated in the cytoplasm of astrocytes. In conclusion, our findings demonstrate that an up-regulation of TbetaR-I is present in patients with temporal lobe epilepsy.

Tetranectin is a potential biomarker in cerebrospinal fluid and serum of patients with epilepsy.

BACKGROUND Tetranectin (TN) is a plasminogen kringle 4 binding protein and regulates fibrinolysis and proteolytic processes via binding to plasminogen. A previous proteomics study identified TN in the cerebrospinal fluid (CSF) of epileptic patients but not in healthy controls. We determined the concentrations of TN in CSF and serum of epileptic patients to evaluate the changes in TN levels after epileptic attack. METHODS We detected TN in the CSF and serum of 64 epileptic patients and 26 healthy subjects using sandwich enzyme-linked immunosorbent assays. RESULTS Compared with the control group, CSF-TN levels increased in epileptic patients while serum-TN levels decreased. These differences were statistically significant. The decrease of serum-TN in patients with drug-refractory epilepsy was the most striking. CONCLUSION CSF-TN and serum-TN are potential biomarkers in epilepsy and drug-refractory epilepsy and would be useful for diagnosis.

Altered expression of synaptotagmin I in temporal lobe tissue of patients with refractory epilepsy.

Synaptotagmin I is a key synaptic protein involved in both exocytosis and endocytosis. We aimed to investigate Synaptotagmin I expression in the anterior temporal neocortex of epilepsy patients, and to explore the possible role of Synaptotagmin I in refractory epilepsy. In the present study, 30 epilepsy patients were divided into refractory epilepsy and non-refractory epilepsy groups, another 15 histologically normal anterior temporal lobes from head trauma patients were used as control group. The results were compared among different groups. The findings were consistently observed using immunohistochemistry, immunofluorescence, and Western blotting technique. Synaptotagmin I was mainly expressed in the cytoplasm and cytomembrane of neurons. The expression of Synaptotagmin I in refractory epilepsy group was significantly higher than that in the control and non-refractory epilepsy groups. These findings provide new information in the epileptogenesis of refractory epilepsy, and suggest that Synaptotagmin I might be involved in human refractory epilepsy. Further studies will be required to elucidate the mechanism by which Synaptotagmin I plays role in refractory epilepsy.

Nongenetic Cause of Epileptic Seizures in 2 Otherwise Healthy Chinese Families : Tetramine-Case Presentation and Literature Survey

Tetramine, a banned rodenticide, is repeatedly reported to induce epileptic seizures in healthy people. Because both doctors and patients are often not aware of earlier tetramine contact, the occurrence of seizures is easily misdiagnosed as primary epilepsy. In this study, 8 cases in 2 families with generalized tonic-clonic seizures, most probably induced by tetramine, are presented. The clinical manifestation, electroencephalogram characteristics, and treatment measures of tetramine poisoning are summarized. There is the possibility of tetramine toxicity as a cause of epidemic epileptic seizures.