F.A. Scorza

Lovastatin decreases the synthesis of inflammatory mediators during epileptogenesis in the hippocampus of rats submitted to pilocarpine-induced epilepsy

Statins may act on inflammatory responses, decreasing oxidative stress and also reducing brain inflammation in several brain disorders. Epileptogenesis is a process in which a healthy brain becomes abnormal and predisposed to generating spontaneous seizures. We previously reported that lovastatin could prevent neuroinflammation in pilocarpine-induced status epilepticus (SE). In this context, this study investigated the long-lasting effects of lovastatin on mRNA expression of proinflammatory cytokines (interleukin-1β, tumor necrosis factor α, interleukin-6) and the antiinflammatory cytokine IL-10 in the hippocampus during epileptogenesis by immunohistochemistry and real time polymerase chain reaction (RT-PCR) during the latent and chronic phases in the epilepsy model induced by pilocarpine in rats. For these purposes, four groups of rats were employed: saline (CONTROL), lovastatin (LOVA), pilocarpine (PILO), and pilocarpine plus lovastatin (PILO+LOVA). After pilocarpine injection (350mg/kg, i.p.), the rats were treated with 20mg/kg of lovastatin via an esophagic probe 2h after SE onset. All surviving rats were continuously treated during 15days, twice/day. The pilocarpine plus lovastatin group showed a significant decrease in the levels of IL-1β, TNF-α, and IL-6 during the latent phase and a decreased expression of IL-1β and TNF-α in the chronic phase when compared with the PILO group. Moreover, lovastatin treatment also induced an increased expression of the antiinflammatory cytokine, IL-10, in the PILO+LOVA group when compared with the PILO group in the chronic phase. Thus, our data suggest that lovastin may reduce excitotoxicity during epileptogenesis induced by pilocarpine by increasing the synthesis of IL-10 and decreasing proinflammatory cytokines in the hippocampus.

Distinctive hippocampal CA2 subfield of the Amazon rodent Proechimys.

Previous data of our laboratory have shown that the Amazonian rodents Proechimys do not present spontaneous seizures in different models of epilepsy, suggesting endogenous inhibitory mechanisms. Here, we describe a remarkably different Proechimys cytoarchitecture organization of the hippocampal cornu Ammonis 2 (CA2) subfield. We identified a very distinctive Proechimys CA2 sector exhibiting disorganized cell presentation of the pyramidal layer and atypical dispersion of the pyramidal-like cells to the stratum oriens, strongly contrasting to the densely packed CA2 cells in the Wistar rats. Studies showed that CA2 is the only cornu ammonis (CA) subfield resistant to the extensive pyramidal neural loss in mesial temporal lobe epilepsy (MTLE) associated to hippocampal sclerosis. Thus, in order to investigate this region, we used Nissl and Timm staining, stereological approach to count neurons and immunohistochemistry to neuronal nuclei (NeuN), parvalbumin (PV), calbindin (CB) and calretinin (CR). We did not notice statistically significant differences in the total number of neurons of the CA2 region between Proechimys and Wistar. However, Proechimys rodents presented higher CA2 volume than Wistar rats. Furthermore, no significant difference in the optical density of parvalbumin-immunoreactivity was found between subject groups. On the other hand, Proechimys presented significant higher density of calbindin and calretinin-immunoreactivity when compared to Wistar rats. In this context, this unique CA2 subfield seen in Proechimys opens up a new set of possibilities to explore the contribution of CA2 neurons in normal and pathological brain circuits.

Could sudden death syndrome (SDS) in chickens (Gallus gallus) be a valid animal model for sudden unexpected death in epilepsy (SUDEP)

Epilepsy is the most common serious neurological disorder and approximately 1% of the population worldwide has epilepsy. Moreover, sudden unexpected death in epilepsy (SUDEP) is the most important direct epilepsy-related cause of death. Information concerning risk factors for SUDEP is conflicting, but potential risk factors include: young age, early onset of epilepsy, duration of epilepsy, uncontrolled seizures, seizure frequency, AED number and winter temperatures. Additionally, the cause of SUDEP is still unknown; however, the most commonly suggested mechanisms are cardiac abnormalities during and between seizures. Similarly, sudden death syndrome (SDS) is a disease characterized by an acute death of well-nourished and seeming healthy Gallus gallus after abrupt and brief flapping of their wings and incidence of SDS these animals has recently increased worldwide. Moreover, the exactly cause of SDS in Gallus gallus is unknown, but is very probable that cardiac abnormalities play a potential role. Due the similarities between SUDEP and SDS and as Gallus gallus behavioral manifestation during SDS phenomenon is close of a tonic-clonic seizure, in this paper we suggest that epilepsy could be a new possible causal factor for SDS.

Enhanced nonsynaptic epileptiform activity in the dentate gyrus after kainate-induced status epilepticus

Understanding the mechanisms that influence brain excitability and synchronization provides hope that epileptic seizures can be controlled. In this scenario, non-synaptic mechanisms have a critical role in seizure activity. The contribution of ion transporters to the regulation of seizure-like activity has not been extensively studied. Here, we examined how non-synaptic epileptiform activity (NEA) in the CA1 and dentate gyrus (DG) regions of the hippocampal formation were affected by kainic acid (KA) administration. NEA enhancement in the DG and suppression in area CA1 were associated with increased NKCC1 expression in neurons and severe neuronal loss accompanied by marked glial proliferation, respectively. Twenty-four hours after KA, the DG exhibited intense microglial activation that was associated with reduced cell density in the infra-pyramidal lamina; however, cellular density recovered 7 days after KA. Intense Ki67 immunoreactivity was observed in the subgranular proliferative zone of the DG, which indicates new neuron incorporation into the granule layer. In addition, bumetanide, a selective inhibitor of neuronal Cl(-) uptake mediated by NKCC1, was used to confirm that the NKCC1 increase effectively contributed to NEA changes in the DG. Furthermore, 7 days after KA, prominent NKCC1 staining was identified in the axon initial segments of granule cells, at the exact site where action potentials are preferentially initiated, which endowed these neurons with increased excitability. Taken together, our data suggest a key role of NKCC1 in NEA in the DG.

In brief: Sudden unexpected death in Parkinson's disease

According to recent studies conducted by the UN, the global prevalence of older people is estimated to further increase reaching 1.4 billion by 2030, 2.1 billion by 2050, and 3.2 billion by 2100.1,2 As life expectancy is increasing, aging is the main risk factor for many neurodegenerative diseases,1,2 including Parkinson’s disease (PD).3 Hence, we read with great interest the elegant article by KadastikEerme and colleagues who demonstrated appropriately the increasing prevalence of PD in Estonia.4 The authors concluded that increased life expectancy of the Estonian population and improved diagnosis of PD contributed most to the increase in disease frequency.4 The authors are correct in their reflections, but this leads us to another point that may determine the prevalence of PD: Mortality of PD, which is still little explored in the literature and not frequently discussed in the neuroscientific community.3 It is clear that PD is not considered a “fatal disease,” but one of the ten most frequently asked questions about PD is as follows: “Can people die from Parkinson’s?”5,6 Obviously, this uncertainty and concern result from reliable data in the literature relating mortality and PD. Corroborating this information, our research group investigated mortality in PD in a research effort particularly since the “Decade of the Brain” declaration to confirm its impact.3 Briefly, almost 97 000 scientific papers related exclusively with PD and an amount of 1650 articles associated to mortality in PD were found,3 demonstrating that only 2% of the research papers published in the medical literature as the “Decade of the Brain” declaration were related to mortality.3 In very general terms, how are the perspectives of mortality in PD? It has been recognized that PD has a reduced life expectancy due to increased mortality compared to the general population.3 Specifically, very wellconducted studies have shown that mortality in PD is not increased in the first 5 years after disease onset, but increases thereafter, with a relative risk of 3.5 after 10 years.7,8 Main causes of death in PD identified by most of the studies are pneumonia and cardiovascular diseases.9,10 These results are comprehensible as it is very well established that cardiac abnormalities found in PD patients are manifold, but the most prominent is cardiac autonomic dysfunction.11 Surprisingly, what is still under debate is the occurrence of “Sudden Unexpected Death in Parkinson’s Disease” (SUDPAR).3,11-14 So far, there is no generally accepted definition for SUDPAR. Concerning a didactic definition, SUDPAR was conceptualized as an unexpected death in a patient with PD without any satisfactory explanation of death as determined by autopsy studies.3 Importantly, SUDPAR is still considered a rare event.3,14 However, neuroscientists are trying to define key risk factors, causal mechanisms (possibly cardiovascular), and effective preventive measures.3,14 While the possible mysteries of SUDPAR are not uncovered, a cooperative strategy between neurologists and cardiologists must be established with regard to SUDPAR. Thus, some comprehensive cardiovascular screening protocols, including routine ECG, stress tests, longterm ECG recordings, echocardiography, cardiac MRI, and lung function tests, could be helpful to capture risk factors for SUDPAR.3 Overall, the population is getting older and the number of individuals with PD will increase. Thus, new cases of SUDPAR should be described in the literature, and the issue should be thoroughly investigated as one of our missions as scientists is not to let SUDPAR statistics become a reality.

012 — (CAM0047) Previous aerobic exercise program does not alter seizure susceptibility in adult female rats

postictal segments, the power in LG and HG frequencies decreased compared with baseline, while the power in HFOs increased in both analyzed regions. Delta postictal segment presented opposite activities in the mPFC and hippocampus, with sustained increase in the mPFC and no difference from baseline in the hippocampus. Discussion/conclusions: Using the present TLE model, we were able to induce late SRSs in an interval of 75 days, which had the EEG onset predominantly in the hippocampus and later spread to the cortex. Our results show electrographic changes in the preictal and postictal segments in all analyzed oscillations in themPFC and at high frequencies in the hippocampus. Changes in theta and HG frequency bands have been associated with cognitive deficits and psychiatric disorders, and an important relationship between changes in HFOs and the process of epileptogenesis has been suggested. The next steps will be the characterization of electrophysiological patterns in association with behavioral alterations generally found in the interictal period. This analysis will possibly provide relevant information about which energy band spectral in these conditions could predict SRSs and/or cognitive deficits.

080 — (TOB0037) Evaluation of neurodevelopmental profile in rats following early-life seizures

Rationale: Neonatal seizures are the most common manifestation of neurological dysfunction in the neonate. Animal data indicate that seizures during development are associated with a high probability of long-term adverse effects such as learning and memory impairment and behavioral changes, but the mechanisms underlying those effects are not completely understood. This study quantified the expression of proteins involved in synaptic transmission (PSD-95, KCC2, and GABAT-1). Methods: The experimental group (EXP) received pilocarpine (380 mg/kg, i.p.), and the control group (CTR) received saline at postnatal day 9. At postnatal day 100, the animals (n= 4 per group) were euthanized, and the hippocampi were dissected for Western blot analysis. The results were analyzed using the Mann–Whitney test. Results: The immunoblot data showed an increase in GABT1, PSD-95, and KCC2 in the experimental group as compared with control rats. Discussion/conclusions: The enhanced expression of PSD-95 suggested a facilitation of the excitatory synaptic transmission, which could be counterbalanced by an increase in both KCC2 expression and GABAT-1 expression, a potential strategy to protect the brain from a new insult. These data raise the interesting possibility that neonatal seizures lead to an imbalance between excitatory neurotransmission and inhibitory neurotransmission.

043 — (MAR0038) The influence of neonatal seizures on epileptogenesis

15 min, respectively]. This result indicates that only the Adolescent-INT group developed cocaine-induced conditioned place preference. Discussion/conclusions: In the present study, we used a dose of cocaine that does not produce conditioned place preference under standard conditions. Therefore, our results indicate that social interaction with an ageand drug treatment-matched conspecific facilitates the development of cocaine-induced conditioned place preference in adolescent, but not adult, mice, suggesting a potential interaction between social conditions and reward elicited by cocaine in adolescents. Acknowledgments/financial support: CAPES, FAPESP, and AFIP.