Social behavior impairment in offspring exposed to maternal seizures in utero

Issues of Women with Epilepsy and Suitable Antiseizure Drugs

Seizure aggravation in women with epilepsy (WWE) tends to occur at two specific times during the menstrual cycle: the perimenstrual phase and the ovulation period. Antiseizure drugs (ASDs), especially those that induce enzymes, can accelerate the metabolism of hormones in oral contraceptives, rendering them less effective. Estrogen in contraceptive pills increases the metabolism of lamotrigine. Physiological changes during pregnancy can significantly impact the pharmacokinetics of ASDs, potentially necessitating adjustments in dosage for women with epilepsy to maintain seizure control. The use of valproate in pregnant women is associated with the highest risk of major congenital malformations among ASDs. Risks of major congenital malformations associated with lamotrigine, levetiracetam, and oxcarbazepine were within the range reported in the general population. Exposure to valproate can lead to lower IQ in offspring. Reduced folic acid levels are linked to orofacial clefts, cardiovascular malformations, and urogenital and limb anomalies in WWE. Decreased folate levels are expected with the use of enzyme-inducing ASDs. However, a high dose of folate was associated with an increased risk of cancer in children of mothers with epilepsy. Most ASDs are generally considered safe for breastfeeding and should be encouraged. However, no single ASD is considered ideal for childbearing WWE. Lamotrigine and levetiracetam are relatively more suitable options for this situation.

Multisensory Stimulation Reverses Memory Impairment in Adrβ3KO Male Mice

Norepinephrine plays an important role in modulating memory through its beta-adrenergic receptors (Adrβ: β₁, β₂ and β₃). Here, we hypothesized that multisensory stimulation would reverse memory impairment caused by the inactivation of Adrβ₃ (Adrβ₃KO) with consequent inhibition of sustained glial-mediated inflammation. To test this, 21- and 86-day-old Adrβ₃KO mice were exposed to an 8-week multisensory stimulation (MS) protocol that comprised gustatory and olfactory stimuli of positive and negative valence; intellectual challenges to reach food; the use of hidden objects; and the presentation of food in ways that prompted foraging, which was followed by analysis of GFAP, Iba-1 and EAAT2 protein expression in the hippocampus (HC) and amygdala (AMY). The MS protocol reduced GFAP and Iba-1 expression in the HC of young mice but not in older mice. While this protocol restored memory impairment when applied to Adrβ₃KO animals immediately after weaning, it had no effect when applied to adult animals. In fact, we observed that aging worsened the memory of Adrβ₃KO mice. In the AMY of Adrβ3KO older mice, we observed an increase in GFAP and EAAT2 expression when compared to wild-type (WT) mice that MS was unable to reduce. These results suggest that a richer and more diverse environment helps to correct memory impairment when applied immediately after weaning in Adrβ₃KO animals and indicates that the control of neuroinflammation mediates this response.

Long-term obesity is associated with depression and neuroinflammation

OBJECTIVE

Obesity is characterized by a state of chronic, low-intensity systemic inflammation frequently associated with insulin resistance and dyslipidemia.

METHODS

Given that chronic inflammation has been implicated in the pathogenesis of mood disorders, we investigated if chronic obesity that was initiated early in life - lasting through adulthood - could be more harmful to memory impairment and mood fluctuations such as depression.

RESULTS

Here we show that pre-pubertal male rats (30 days old) treated with a high-fat diet (40%) for 8-months gained ~50% more weight when compared to controls, exhibited depression and anxiety-like behaviors but no memory impairment. The prefrontal cortex of the obese rats exhibited an increase in the expression of genes related to inflammatory response, such as NFKb, MMP9, CCl2, PPARb, and PPARg. There were no alterations in genes known to be related to depression.

CONCLUSION

Long-lasting obesity with onset in prepuberal age led to depression and neuroinflammation but not to memory impairment.

Increased Endocannabinoid Signaling Reduces Social Motivation in Intact Rats and Does Not Affect Animals Submitted to Early-Life Seizures

The early life status epilepticus (SE) causes high anxiety and chronic socialization abnormalities, revealed by a low preference for social novelty and deficit in social discrimination. This study investigated the involvement of the endocannabinoid system on the sociability in this model, due to its role in social motivation regulation. Male Wistar rats at postnatal day 9 were subjected to pilocarpine-induced neonatal SE and controls received saline. From P60 the groups received vehicle or JZL195 2 h before each behavioral test to increase endocannabinoids availability. In the sociability test, animals subjected to neonatal SE exhibited impaired sociability, characterized by social discrimination deficit, which was unaffected by the JZL195 treatment. In contrast, JZL195-treated control rats showed low sociability and impaired social discrimination. The negative impact of JZL195 over the sociability in control rats and the lack of effect in animals subjected to neonatal SE was confirmed in the social memory paradigm. In this paradigm, as expected for vehicle-treated control rats, the investigation toward the same social stimulus decreased with the sequential exposition and increased toward a novel stimulus. In animals subjected to neonatal SE, regardless of the treatment, as well as in JZL195-treated control rats, the investigation toward the same social stimulus was significantly reduced with no improvement toward a novel stimulus. Concerning the locomotion, the JZL195 increased it only in control rats. After behavioral tests, brain tissues of untreated animals were used for CB1 receptor quantification by Elisa and for gene expression by RT-PCR: no difference between control and experimental animals was noticed. The results reinforce the evidence that the early SE causes chronic socialization abnormalities, revealed by the low social interest for novelty and impaired social discrimination. The dual FAAH/MAGL inhibitor (JZL195) administration before the social encounter impaired the social interaction in intact rats with no effect in animals subjected to early-life seizures.

Wistar audiogenic rats display abnormal behavioral traits associated with artificial selection for seizure susceptibility

Accumulating evidence from different animal models has contributed to the understanding of the bidirectional comorbidity associations between the epileptic condition and behavioral abnormalities. A strain of animals inbred to enhance seizure predisposition to high-intensity sound stimulation, the Wistar audiogenic rat (WAR), underwent several behavioral tests: forced swim test (FST), open-field test (OFT), sucrose preference test (SPT), elevated plus maze (EPM), social preference (SP), marble burying test (MBT), inhibitory avoidance (IAT), and two-way active avoidance (TWAA). The choice of tests aimed to investigate the correlation between underlying circuits believed to be participating in both WAR's innate susceptibility to sound-triggered seizures and the neurobiological substrates associated with test performance. Comparing WAR with its Wistar counterpart (i.e., resistant to audiogenic seizures) showed that WARs present behavioral despair traits (e.g., increased FST immobility) but no evidence of anhedonic behavior (e.g., increased sucrose consumption in SPT) or social impairment (e.g., no difference regarding juvenile exploration in SP). In addition, tests suggested that WARs are unable to properly evaluate degrees of aversiveness (e.g., performance on OFT, EPM, MBT, IAT, and TWAA). The particularities of the WAR model opens new venues to further untangle the neurobiology underlying the co-morbidity of behavioral disorders and epilepsy. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".

Effect of diazepam on sociability of rats submitted to neonatal seizures

Status epilepticus (SE), an acute condition characterized by repetitive or ongoing seizures activity, may produce long-term deleterious consequences. Previous data demonstrated that Wistar rats subjected to neonatal SE displayed autistic behavior, characterized by social play impairment, low preference by novelty, deficit in social discrimination; anxiety related behavior and stereotyped behavior with no changes in locomotor activity (doi: http://dx.doi.org/10.1007/s00702-010-0460-1, doi: http://dx.doi.org/10.3389/fnbeh.2013.00036, doi: http://dx.doi.org/10.1007/s00702-014-1291-2[1], [2], [3]). Taking into account the bi-directional relationship between the state of anxiety and social interaction (doi: http://dx.doi.org/10.1007/s10567-009-0062-3[4]), we evaluated the impact of the state of anxiety on social interaction. Male Wistar rats at postnatal day 9 were subjected to pilocarpine-induced neonatal SE (380 mg/kg, ip) and the controls received 0.9% saline (0.1 ml/10 g). The groups received saline or diazepam (1.0 mg/kg) 45 min prior each behavioral testing that started from 60 days of postnatal life. In the open field, rats subjected to neonatal seizure exhibited less central zone activity as compared to animals treated with diazepam, with no changes in the total locomotor activity. In elevated plus maze, rats subjected to neonatal seizure and treated with diazepam exhibited higher locomotor activity and spent more time on the open arms as compared to untreated animals. In approach phase of sociability paradigm, animals subjected to neonatal seizures similarly to controls, regardless the treatment, spent more time with social stimulus as compared to non social stimulus. In social novelty phase of sociability paradigm, animals subjected to neonatal seizures differently of controls, regardless the treatment, spent similar time with familiar and novel stimulus.

The impact of seizures on pregnancy and delivery

PURPOSE AND METHODS

The treatment of women with epilepsy during pregnancy is known to increase the risk of teratogenic effects. Whether seizures during pregnancy have a deleterious effect on the developing child is difficult to determine, but recent animal studies, case studies, cohort studies and population studies have provided useful insights.

RESULTS AND CONCLUSION

Seizures before pregnancy are a predictor for seizures during pregnancy, and catamenial epilepsy may also predict the course of seizures during pregnancy. A first epileptic seizure may also have implications for the pregnancy, depending on the seizure aetiology. Seizures affecting maternal awareness and responsiveness may have cardiac effects on the foetus and may impact on the weight of the newborn. Status epilepticus in pregnancy is rare, but isolated cases of perinatal death and malformations after status epilepticus have been reported in women on antiepileptic drugs. Seizures during delivery occur in about 2% of pregnancies of women with epilepsy, and case studies indicate that the foetal heart may be affected. However, a diagnosis of epilepsy is not an indication per se for caesarean delivery. A well-planned pregnancy can reduce the likelihood of seizures occurring.

Early life seizures in female rats lead to anxiety-related behavior and abnormal social behavior characterized by reduced motivation to novelty and deficit in social discrimination

Previously, we demonstrated that male Wistar rats submitted to neonatal status epilepticus showed abnormal social behavior characterized by deficit in social discrimination and enhanced emotionality. Taking into account that early insult can produce different biological manifestations in a gender-dependent manner, we aimed to investigate the social behavior and anxiety-like behavior in female Wistar rats following early life seizures. Neonate female Wistar rats at 9 days postnatal were subject to pilocarpine-induced status epilepticus and the control received saline. Behavioral tests started from 60 days postnatal and were carried out only during the diestrus phase of the reproductive cycle. In sociability test experimental animals exhibited reduced motivation for social encounter and deficit in social discrimination. In open field and the elevated plus maze, experimental animals showed enhanced emotionality with no changes in basal locomotor activity. The results showed that female rats submitted to neonatal status epipepticus showed impaired social behavior, characterized by reduced motivation to novelty and deficit in social discrimination in addition to enhanced emotionality.

Altered anxiety-related and abnormal social behaviors in rats exposed to early life seizures

Neonatal seizures are the most common manifestation of neurological dysfunction in the neonate. The prognosis of neonatal seizures is highly variable, and the controversy remains whether the severity, duration, or frequency of seizures may contribute to brain damage independently of its etiology. Animal data indicates that seizures during development are associated with a high probability of long-term adverse effects such as learning and memory impairment, behavioral changes and even epilepsy, which is strongly age dependent, as well as the severity, duration, and frequency of seizures. In preliminary studies, we demonstrated that adolescent male rats exposed to one-single neonatal status epilepticus (SE) episode showed social behavior impairment, and we proposed the model as relevant for studies of developmental disorders. Based on these facts, the goal of this study was to verify the existence of a persistent deficit and if the anxiety-related behavior could be associated with that impairment. To do so, male Wistar rats at 9 days postnatal were submitted to a single episode of SE by pilocarpine injection (380 mg/kg, i.p.) and control animals received saline (0.9%, 0.1 mL/10 g). It was possible to demonstrate that in adulthood, animals exposed to neonatal SE displayed low preference for social novelty, anxiety-related behavior, and increased stereotyped behavior in anxiogenic environment with no locomotor activity changes. On the balance, these data suggests that neonatal SE in rodents leads to altered anxiety-related and abnormal social behaviors.

Sex and hormonal influences on seizures and epilepsy

Epilepsy is the third most common chronic neurological disorder. Clinical and experimental evidence supports the role of sex and influence of sex hormones on seizures and epilepsy as well as alterations of the endocrine system and levels of sex hormones by epileptiform activity. Conversely, seizures are sensitive to changes in sex hormone levels, which in turn may affect the seizure-induced neuronal damage. The effects of reproductive hormones on neuronal excitability and seizure-induced damage are complex to contradictory and depend on different mechanisms, which have to be accounted for in data interpretation. Both estradiol and progesterone/allopregnanolone may have beneficial effects for patients with epilepsy. Individualized hormonal therapy should be considered as adjunctive treatment in patients with epilepsy to improve seizure control as well as quality of life.