Potential Pleiotropic Genes and Shared Biological Pathways in Epilepsy and Depression Based on GWAS Summary Statistics.

Current epidemiological and experimental studies have indicated the overlapping genetic foundation of epilepsy and depression. However, the detailed pleiotropic genetic etiology and neurobiological pathways have not been well understood, and there are many variants with underestimated effect on the comorbidity of the two diseases. Utilizing genome-wide association study (GWAS) summary statistics of epilepsy (15,212 cases and 29,677 controls) and depression (170,756 cases and 329,443 controls) from large consortia, we assessed the integrated gene-based association with both diseases by Multimarker Analysis of Genomic Annotation (MAGMA) and Fisher's meta-analysis. On the one hand, shared genes with significantly altered transcripts in Gene Expression Omnibus (GEO) data sets were considered as possible pleiotropic genes. On the other hand, the pathway enrichment analysis was conducted based on the gene lists with nominal significance in the gene-based association test of each disease. We identified a total of two pleiotropic genes (CD3G and SLCO3A1) with gene expression analysis validated and interpreted twenty-five common biological process supported with literature mining. This study indicates the potentially shared genes associated with both epilepsy and depression based on gene expression, meta-data analysis, and pathway enrichment strategy along with traditional GWAS and provides insights into the possible intersecting pathways that were not previously reported.

Novel insights into the effect of paroxetine administration in pilocarpine­induced chronic epileptic rats.

The aim of the present study was to investigate the role of paroxetine intervention in epilepsy, and its association with the expression of serotonin transporter (SERT) and hippocampal apoptosis. Thirty adult male Sprague Dawley rats were divided into control vehicle (n=6) and epileptic (n=24) groups. Status epilepticus (SE) was induced via systemic injection of pilocarpine, and seizure activity was monitored via video electroencephalogram. The epileptic group was then randomly divided into two groups; Four weeks following SE induction, paroxetine (5 mg/kg/day; SE + paroxetine group) or normal saline (SE group) was intraperitoneally injected for 4 weeks. Brain tissue was collected to evaluate apoptosis via terminal deoxynucleotidyl transferase dUTP nick­end labeling. SERT, B­cell lymphoma­2 (Bcl­2) and brain derived neurotropic factor (BDNF) expression levels were evaluated by western blotting, and miR­16 expression was evaluated by reverse transcription­quantitative polymerase chain reaction. Paroxetine did not affect the mortality of the pilocarpine­induced chronic epileptic rats. Spontaneous recurrent seizures (SSRs) were observed 7­28 days following SE induction. The frequency and stage of the SSRs were reduced by paroxetine administration. Apoptotic cells were observed in the epileptic hippocampus. Following paroxetine intervention, the staining intensity and number of apoptotic cells were significantly decreased. Expression levels of BDNF and Bcl­2 were lower in the SE group compared with the vehicle group. The former was not altered by paroxetine injection; however, the latter was increased. In the SE group, SERT expression was not altered in the raphe nucleus but was decreased in the hippocampus. Following paroxetine administration, SERT expression was decreased in the raphe nucleus and increased in the hippocampus. In the SE group, miR­16 expression was decreased in the raphe nucleus and increased in the hippocampus. Following paroxetine administration, miR­16 expression was not altered in the raphe nucleus but was reduced in the hippocampus. In conclusion, the seizures and hippocampal apoptosis observed in chronic epileptic rats were alleviated by paroxetine treatment. This effect may be associated with the reduced Bcl­2 and BDNF expression and the modulation of SERT expression. The alterations in miR­16 expression may provide a potential explanation for the modulation of apoptosis; however, further research is required to determine the complete underlying molecular mechanism.

Comparative Efficacy and Safety of Nine Anti-Platelet Therapies for Patients with Ischemic Stroke or Transient Ischemic Attack: a Mixed Treatment Comparisons.

Anti-platelet treatments, an effective anti-thrombotic therapy, are widely used in non-cardioembolic ischemic stroke or transient ischemic attack (TIA), including aspirin, cilostazol, clopidogrel, and other mono or dual therapies, while the optimal choice remains uncertain. All the literatures of 38 eligible randomized control trials were searched in PubMed, Embase, and China National Knowledge Internet (CNKI) without language limitation. And, nine anti-platelet therapies were assessed, including aspirin, clopidogrel, cilostazol, ticlopidine, triflusal, terutroban, sarpogrelate, dipyridamole plus aspirin, and clopidogrel plus aspirin. Additionally, we extract data of composite vascular events, major bleeding, ischemic stroke, intracranial hemorrhage, and all-cause death, as indicators of efficacy and safety. And among them, composite vascular events were the primary outcome. The binary outcomes were expressed as odds ratios (ORs) with corresponding 95 % confidence intervals (CIs). Both traditional meta-analysis and network meta-analysis were performed. Besides, for each outcome, the rank order was applied to reflect the superiority of every therapy compared with others, using the surface under the cumulative ranking curve (SUCRA). A cluster analysis was also conducted. Through the network meta-analysis, the synthesized data shows that cilostazol performed best on composite vascular events compared with placebo (OR = 0.62, 95 % CI 0.46-0.83) and aspirin (OR = 0.71, 95 % CI 0.53-0.95). In terms of ischemic stroke, clopidogrel plus aspirin seems the optimal, and it has significant difference between placebo (OR = 0.53, 95 % CI 0.35-0.74) and aspirin (OR = 0.75, 95 % CI 0.61-0.95). Meanwhile, cilostazol is also the first rank in major bleeding, especially when it is in contrast to aspirin (OR = 0.13, 95 % CI 0.02-0.70) and clopidogrel plus aspirin (OR = 0.09, 95 % CI 0.01-0.50). There is no significant difference among these nine treatments and placebo, as to all-cause death and intracranial hemorrhage. According to the cluster analysis, cilostazol can be the best choice with comprehensive assessment of composite vascular events, ischemic stroke and major bleeding. Based on this network meta-analysis, cilostazol was recommended as the optimal choice with good performance in both efficacy and safety for patient with ischemic stroke or TIA among nine anti-platelet therapies.

Seizure-induced 5-HT release and chronic impairment of serotonergic function in rats.

We analyzed the dynamic concentration change of serotonin (5-HT) and its main metabolite 5-hydroxyindoleacetic acid (5-HIAA) within the epileptic hippocampus in rats. Seizure was induced by systemic injection of pilocarpine (320mg/kg, i.p.). Using electroencephalography (EEG) recordings, we found that primary seizure discharge was induced 30min after pilocarpine administration and that recurrent discharge peaked 14d after the onset of status epilepticus (SE). The extracellular fluid in the hippocampus was sampled by microdialysis from conscious animals at various time points before and after SE. The concentrations of 5-HT and 5-HIAA in the samples were measured by high-performance liquid chromatography and electrochemical detection (HPLC-ECD). Interestingly, 5-HT levels in the hippocampus were dramatically increased within the 30min following SE. This reversed to basal level by 4d after SE and continued to drop to 48% at 7d and 28% of basal level 14d after SE. Accordingly, a marked increase of 5-HIAA in the hippocampus appeared at 2d after SE, then gradually declined to levels below baseline. To identify serotonergic neurons in the raphe nuclei (a major source of 5-HT release in the brain), brain sections were immunostained for tryptophan hydroxylase (TPH). The number of TPH positive neurons and the intensity of TPH staining significantly decreased at 28d after SE. These data suggest that pilocarpine induces depletion of 5-HT in the hippocampus and significantly compromise serotonergic neurons in the raphe nuclei. The loss of serotonergic function may play a significant role in the pathophysiology of epilepsy.

[Effect of serotonin depletion on seizures learning-memory in pilocarpine-induced epileptic rats].

OBJECTIVE: To investigate the relationship between serotonin (5-HT) and epilepsy and the mechanism of learning-memory in pilocarpine (PILO)-induced epileptic rats after 5,7-dihydroxytryptamine (5,7-DHT) microinjection in median raphe nucleus. METHODS: Adult S D rats were randomly divided into 3 groups: PILO group, PILO+ 5,7-DHT group, vehicle control group; PILO group was divided into two groups by status epilepticus (SE): PILO + SE group and PILO - SE group. The rats' seizures and cortex electroencephalography (EEG) were observed by video EEG. The rats' spatial learning-memory was evaluated by Morris water maze. Finally, serotonergic neuron in raphe nuclei was observed by immunohistochemistry. RESULTS: After treatment of 5,7-DHT (PILO + 5,7-DHT group), the success rate, the mortality and the frequency of chronic spontaneous seizures in pilocarpine-induced epilepsy model were all improved. Compared with the control group, the number of serotonergic neuron in raphe nuclei was decrease in PILO + SE group (P < 0.05). Moreover, it's extremely decrease in PILO + 5,7-DHT group (P < 0.01). Compared with control group, the mean escape latency was prolonged, the times of crossing target was decreased and the retention time in target zone was shortened in PILO + SE group (P < 0.05), but there was no significant difference between PILO + SE group and PILO + 5,7-DHT group. CONCLUSION: Depletion of serotonin may facility the rats' epileptic seizures, but we could not interpret which may cause epileptic rats' cognitive deficit.

[The effect of high frequency stimulation of epileptic foci on the release of glutamate and gamma-aminobutyric acid in hippocampus of the kainic acid-kindled rats].

OBJECTIVE: To observe the dynamics of hippocampal release of glutamate (Glu) and gamma-aminobutyric acid (GABA) in epilepsy (TLE) after administration with high frequency stimulation (HFS). METHODS: The SD were divided into four groups (n =10): (1) Control group (KB) the rats were injected intraperitoneally with saline 0.9%. (2) Kainic acid (KA) group: the rats were injected with KA. (3) Pseudo-deep brain stimulation (DBS) group: the KA-induced rats were implanted with rheophores alone. (4) DBS group: KA induced-rats with DBS in hippocampal epileptic foci. We then collected hippocampal extracellular fluid by microdialysis and the levels of Glu and GABA were measured by high-performance liquid chromatography (HPLC) and fluorescence detection. RESULTS: There was no difference in the baseline of Glu and GABA in the four groups. In contrast, a significant increase in the content of Glu and GABA was shown in the three periods of KA-kindled seizures. Electrical stimulation of hippocampus resulted in a decrease of hippocampal Glu contents, while there was no change in GABA contents. Additionally, HFS of hippocampus normalized the Glu/GABA ratio in the chronic period of seizures. CONCLUSION: The high frequency stimulation of epileptic foci may protect against seizures by modulating the extracellular release of hippocampal Glu.