Effects of omega-3 dietary supplement in prevention of positive, negative and cognitive symptoms: a study in adolescent rats with ketamine-induced model of schizophrenia

Pre-adolescence repeat exposure to sub-anesthetic doses of ketamine induces long-lasting behaviors and cognition impairment in male and female rat adults

In pre-adolescence, repeated anesthesia may be required for therapeutic interventions. Adult cognitive and neurobehavioral problems may result from preadolescent exposure to anesthetics. This study examined the long-term morphological and functional effects of repeated sub-anesthetic doses of ketamine exposure on male and female rat adults during pre-adolescence. Weaned 48 pre-adolescent rats from eight mothers and were randomly divided into four equal groups: control group and the ketamine group of males and females (20 mg/kg daily for 14 days); then animals received care for 20-30 days. Repeated exposure to sub-anesthetic doses of ketamine on cognitive functions was assayed using Social discrimination and novel object tests. Besides, an elevated plus maze and fear conditioning apparatus were utilized to determine exploratory and anxiety-like behavior in adults. Toluidine blue stain was used to evaluate the number of dead neurons in the hippocampus, and the effects of ketamine on synaptic plasticity were compared in the perforant pathway of the CA1 of the hippocampus. Our study indicates that repeated exposure to sub-anesthetic doses of ketamine during pre-adolescence can result in neurobehavioral impairment in male and female rat adulthood but does not affect anxiety-like behavior. We found a significant quantifiable increase in dark neurons. Recorded electrophysiologically, repeat sub-anesthetic doses of ketamine resulted in hampering long-term potentiation and pair pulse in male adult animals. Our results showed that repeated exposure to sub-anesthetic doses of ketamine during pre-adolescence can induce hippocampus and neuroplasticity changes later in adulthood. This study opens up a new line of inquiry into potential adverse outcomes of repeated anesthesia exposure in pre-adolescent rats.

Amphetamine disrupts dopamine axon growth in adolescence by a sex-specific mechanism in mice

Initiating drug use during adolescence increases the risk of developing addiction or other psychopathologies later in life, with long-term outcomes varying according to sex and exact timing of use. The cellular and molecular underpinnings explaining this differential sensitivity to detrimental drug effects remain unexplained. The Netrin-1/DCC guidance cue system segregates cortical and limbic dopamine pathways in adolescence. Here we show that amphetamine, by dysregulating Netrin-1/DCC signaling, triggers ectopic growth of mesolimbic dopamine axons to the prefrontal cortex, only in early-adolescent male mice, underlying a male-specific vulnerability to enduring cognitive deficits. In adolescent females, compensatory changes in Netrin-1 protect against the deleterious consequences of amphetamine on dopamine connectivity and cognitive outcomes. Netrin-1/DCC signaling functions as a molecular switch which can be differentially regulated by the same drug experience as function of an individual's sex and adolescent age, and lead to divergent long-term outcomes associated with vulnerable or resilient phenotypes.

Animal Models of Relevance to the Schizophrenia Prodrome

Patients with schizophrenia often undergo a prodromal phase prior to diagnosis. Given the absence of significant therapeutic improvements, attention has recently shifted to the possibility of intervention during this early stage to delay or diminish symptom severity or even prevent onset. Unfortunately, the 20 or so trials of intervention to date have not been successful in either preventing onset or improving long-term outcomes in subjects who are at risk of developing schizophrenia. One reason may be that the biological pathways an effective intervention must target are not static. The prodromal phase typically occurs during late adolescence, a period during which a number of brain circuits and structures are still maturing. We propose that developing a deeper understanding of which circuits/processes and brain structures are still maturing at this time and which processes drive the transition to schizophrenia will take us a step closer to developing better prophylactic interventions. Fortunately, such knowledge is now emerging from clinical studies, complemented by work in animal models. Our task here is to describe what would constitute an appropriate animal model to study and to potentially intervene in such processes. Such a model would allow invasive analysis of the cellular and molecular substrates of the progressive neurobiology that defines the schizophrenia prodrome and hopefully offer valuable insights into potential prophylactic targets.

Niacin mitigates blood-brain barrier tight junctional proteins dysregulation and cerebral inflammation in ketamine rat model of psychosis: Role of GPR109A receptor

Dysregulated inflammatory responses and blood-brain barrier (BBB) dysfunction are recognized as central factors in the development of psychiatric disorders. The present study was designed to evaluate the effect of niacin on BBB integrity in ketamine-induced model of psychosis. Meanwhile, mepenzolate bromide (MPN), a GPR109A receptor blocker, was used to investigate the role of this receptor on the observed niacin's effect. Male Wistar rats received ketamine (30 mg/kg/day, i.p) for 5 consecutive days and then niacin (40 mg/kg/day, p.o), with or without MPN (5 mg/kg/day, i.p), was given for the subsequent 15 days. Three days before the end of experiment, rats were behaviorally tested using open field, novel object recognition, social interaction, and forced swimming tests. Niacin significantly ameliorated ketamine-induced behavioral deficits, amended gamma aminobutyric acid and glutamate concentration, decreased tumor necrosis factor-α and matrix metallopeptidase 9 levels, and increased netrin-1 contents in the hippocampus of rats. Niacin also augmented the hippocampal expression of ZO-1, occludin, and claudin-5 proteins, indicating the ability of niacin to restore the BBB integrity. Moreover, the histopathologic changes in hippocampal neurons were alleviated. Since all the beneficial effects of niacin in the present investigation were partially abolished by the co-administration of MPN; GPR109A receptor was proven to partially mediate the observed antipsychotic effects of niacin. These data revealed that GPR109A-mediated signaling pathways might represent potential targets for therapeutic interventions to prevent or slow the progression of psychosis.

Role of the NRG1/ErbB4 and PI3K/AKT/mTOR signaling pathways in the anti-psychotic effects of aripiprazole and sertindole in ketamine-induced schizophrenia-like behaviors in rats

Schizophrenia is a common mental disorder affecting patients' thoughts, behavior, and cognition. Recently, the NRG1/ErbB4 signaling pathway emerged as a candidate therapeutic target for schizophrenia. This study investigates the effects of aripiprazole and sertindole on the NRG1/ErbB4 and PI3K/AKT/mTOR signaling pathways in ketamine-induced schizophrenia in rats. Young male Wistar rats received ketamine (30 mg/kg, intraperitoneally) for 5 consecutive days and aripiprazole (3 mg/kg, orally) or sertindole (2.5 mg/kg, orally) for 14 days. The proposed pathway was investigated by injecting LY294002 (a selective PI3K inhibitor) (25 μg/kg, intrahippocampal injection) 30 min before the drugs. Twenty-four hours after the last injection, animals were subjected to behavioral tests: the open field test, sucrose preference test, novel object recognition task, and social interaction test. Both aripiprazole and sertindole significantly ameliorated ketamine-induced schizophrenic-like behavior, as expected, because of their previously demonstrated antipsychotic activity. Besides, both drugs alleviated ketamine-induced oxidative stress and neurotransmitter level changes in the hippocampus. They also increased the gamma-aminobutyric acid and glutamate levels and glutamate decarboxylase 67 and parvalbumin mRNA expression in the hippocampus. Moreover, aripiprazole and sertindole increased the NRG1 and ErbB4 mRNA expression levels and PI3K, p-Akt, and mTOR protein expression levels. Interestingly, pre-injecting LY294002 abolished all the effects of the drugs. This study reveals that the antipsychotic effects of aripiprazole and sertindole are partly due to oxidative stress reduction as well as NRG1/ErbB4 and PI3K/AKT/mTOR signaling pathways activation. The NRG1/ErbB4 and PI3K signaling pathways may offer a new therapeutic approach for treating schizophrenia in humans.

Involvement of anti-inflammatory, antioxidant, and BDNF up-regulating properties in the antipsychotic-like effect of the essential oil of Alpinia zerumbet in mice: a comparative study with olanzapine

The current drug therapy for schizophrenia effectively treats acute psychosis and its recurrence; however, this mental disorder's cognitive and negative symptoms are still poorly controlled. Antipsychotics present important side effects, such as weight gain and extrapyramidal effects. The essential oil of Alpinia zerumbet (EOAZ) leaves presents potential antipsychotic properties that need further preclinical investigation. Here, we determined EAOZ effects in preventing and reversing schizophrenia-like symptoms (positive, negative, and cognitive) induced by ketamine (KET) repeated administration in mice and putative neurobiological mechanisms related to this effect. We conducted the behavioral evaluations of prepulse inhibition of the startle reflex (PPI), social interaction, and working memory (Y-maze task), and verified antioxidant (GSH, nitrite levels), anti-inflammatory [interleukin (IL)-6], and neurotrophic [brain-derived neurotrophic factor (BDNF)] effects of this oil in hippocampal tissue. The atypical antipsychotic olanzapine (OLZ) was used as standard drug therapy. EOAZ, similarly to OLZ, prevented and reversed most KET-induced schizophrenia-like behavioral alterations, i.e., sensorimotor gating deficits and social impairment. EOAZ had a modest effect on the prevention of KET-associated working memory deficit. Compared to OLZ, EOAZ showed a more favorable side effects profile, inducing less cataleptic and weight gain changes. EOAZ efficiently protected the hippocampus against KET-induced oxidative imbalance, IL-6 increments, and BDNF impairment. In conclusion, our data add more mechanistic evidence for the anti-schizophrenia effects of EOAZ, based on its antioxidant, anti-inflammatory, and BDNF up-regulating actions. The absence of significant side effects observed in current antipsychotic drug therapy seems to be an essential benefit of the oil.

Nutrition, nutritional deficiencies, and schizophrenia: An association worthy of constant reassessment

Schizophrenia is a mental health disorder that occurs worldwide, cutting across cultures, socioeconomic groups, and geographical barriers. Understanding the details of the neurochemical basis of schizophrenia, factors that contribute to it and possible measures for intervention are areas of ongoing research. However, what has become more evident is the fact that in targeting the neurochemical imbalances that may underlie schizophrenia, the type of response seen with currently available phamacotherapeutic agents does not provide all the answers that are needed. Therefore, the possible contribution of non-pharmacological approaches to schizophrenia management is worthy of consideration. In recent times, research is beginning to show nutrition may play a possibly significant role in schizophrenia, affecting its development, progression and management; however, while attempts had been made to examine this possible relationship from different angles, articles addressing it from a holistic point of view are not common. In this review, we examine existing scientific literature dealing with the possible relationship between nutrition and schizophrenia, with a view to elucidating the impact of diet, nutritional deficiencies and excesses on the aetiology, progression, management and outcome of schizophrenia. Secondly, the effect of nutritional supplements in prevention, as sole therapy, or adjuncts in schizophrenia management are examined.

Enhancement of Oxytocin in the Medial Prefrontal Cortex Reverses Behavioral Deficits Induced by Repeated Ketamine Administration in Mice

Ketamine is a popular recreational substance of abuse that induces persistent behavioral deficits. Although disrupted oxytocinergic systems have been considered to modulate vulnerability to developing drugs of abuse, the involvement of central oxytocin in behavioral abnormalities caused by chronic ketamine has remained largely unknown. Herein, we aimed to investigate the potential role of oxytocin in the medial prefrontal cortex (mPFC) in social avoidance and cognitive impairment resulting from repeated ketamine administration in mice. We found that ketamine injection (5 mg/kg, i.p.) for 10 days followed by a 6-day withdrawal period induced behavioral disturbances in social interaction and cognitive performance, as well as reduced oxytocin levels both at the periphery and in the mPFC. Repeated ketamine exposure also inhibited mPFC neuronal activity as measured by a decrease in c-fos-positive cells. Furthermore, direct microinjection of oxytocin into the mPFC reversed the social avoidance and cognitive impairment following chronic ketamine exposure. In addition, oxytocin administration normalized ketamine-induced inflammatory cytokines including TNF-α, IL-6, and IL-1β levels. Moreover, the activation of immune markers such as neutrophils and monocytes, by ketamine was restored in oxytocin-treated mice. Finally, the reversal effects of oxytocin on behavioral performance were blocked by pre-infusion of the oxytocin receptor antagonist atosiban into the mPFC. These results demonstrate that enhancing oxytocin signaling in the mPFC is a potential pathway to reverse social avoidance and cognitive impairment caused by ketamine, partly through inhibition of inflammatory stimulation.

Shared Biological Pathways between Antipsychotics and Omega-3 Fatty Acids: A Key Feature for Schizophrenia Preventive Treatment?

Schizophrenia typically emerges during adolescence, with progression from an ultra-high risk state (UHR) to the first episode of psychosis (FEP) followed by a chronic phase. The detailed pathophysiology of schizophrenia and the factors leading to progression across these stages remain relatively unknown. The current treatment relies on antipsychotics, which are effective for FEP and chronic schizophrenia but ineffective for UHR patients. Antipsychotics modulate dopaminergic and glutamatergic neurotransmission, inflammation, oxidative stress, and membrane lipids pathways. Many of these biological pathways intercommunicate and play a role in schizophrenia pathophysiology. In this context, research of preventive treatment in early stages has explored the antipsychotic effects of omega-3 supplementation in UHR and FEP patients. This review summarizes the action of omega-3 in various biological systems involved in schizophrenia. Similar to antipsychotics, omega-3 supplementation reduces inflammation and oxidative stress, improves myelination, modifies the properties of cell membranes, and influences dopamine and glutamate pathways. Omega-3 supplementation also modulates one-carbon metabolism, the endocannabinoid system, and appears to present neuroprotective properties. Omega-3 has little side effects compared to antipsychotics and may be safely prescribed for UHR patients and as an add-on for FEP patients. This could to lead to more efficacious individualised treatments, thus contributing to precision medicine in psychiatry.

Effects of maternal folic acid supplementation on nuclear methyltransferase activity of adult rats subjected to an animal model of schizophrenia

INTRODUCTION

Schizophrenia is considered one of the most disabling and severe human diseases worldwide. The etiology of schizophrenia is thought to be multifactorial and evidence suggests that DNA methylation can play an important role in underlying pivotal neurobiological alterations of this disorder. Some studies have demonstrated the effects of dietary supplementation as an alternative approach to the prevention of schizophrenia, including folic acid. However, no study has ever investigated the role of such supplementation in altering the DNA methylation system in the context of schizophrenia.

OBJECTIVES

The present study aims to investigate the effects of maternal folic acid supplementation at different doses on nuclear methyltransferase activity of adult rat offspring subjected to an animal model schizophrenia induced by ketamine.

METHODS

Adult female Wistar rats, (60 days old) received folic acid-deficient diet, control diet, or control diet plus folic acid supplementation (at 5, 10, or 50 mg/kg) during pregnancy and lactation. After reaching adulthood (60 days), the male offspring of these dams were subjected to the animal model of schizophrenia induced by 7 days of ketamine intraperitoneal injection (25 mg/kg). After the 7-day protocol, the activity of nuclear methyltransferase was evaluated in the brains of the offspring.

RESULTS

Maternal folic acid supplementation at 50 mg/kg increased methyltransferase activity in the frontal cortex, while 10 mg/kg increased methyltransferase activity in the hippocampus. In the striatum of offspring treated with ketamine, maternal deficient diet, control diet, and folic acid supplementation at 5 mg/kg decreased methyltransferase activity compared to the control group. The folic acid supplementation at 10 and 50 mg/kg reversed this ketamine effect.

CONCLUSIONS

Maternal FA deficiency could be related to schizophrenia pathophysiology, while FA supplementation could present a protective effect since it demonstrated persistent effects in epigenetic parameters in adult offspring.

Does Exposure of Smart Phones during Pregnancy Affect the Offspring's Ovarian Reserve? A Rat Model Study

We investigated the effect of prenatal exposure to smart phone radiation and the protective effect of omega-3 on ovarian reserve of offspring. Methods: 24 pregnant Wistar albino rats were divided into four groups. Group-I received neither radiofrequency (RF) radiation nor omega-3, group-II received RF, group-III received RF radiation and 300 mg omega-3 and group-IV received RF radiation and 600 mg Omega-3 till birth. At 42 days, bilateral oophorectomy was performed on all female offspring for follicle count and immunohistochemical staining (GDF9, FOXO1 and TUNEL). Results: Group-II had significantly lower mean number of primordial (p = 0.006), secondary follicles(p = 0.003) and a higher atresia score. Group-III variables were comparable with group-I variables. Group-IV had statistically higher median number of atretic follicles than group-I (p = 0.023). Conclusions: Ovarian reserve of offspring diminished with RF exposure during pregnancy. Omega-3 supplementation during pregnancy may reduce the potential premature ovarian failure.

Sex influences in the preventive effects of peripubertal supplementation with N-3 polyunsaturated fatty acids in mice exposed to the two-hit model of schizophrenia

Schizophrenia is a devastating neurodevelopmental disorder. The animal model based on perinatal immune activation, as first-hit, combined with peripubertal stress, as a second hit, has gained evidence in recent years. Omega-3 polyunsaturated fatty acids (n3-PUFAs) is being a promise for schizophrenia prevention. Nevertheless, the influence of sex in schizophrenia neurobiology and prevention has been neglected. Thus, the present study evaluates the preventive effects of n3-PUFAs in both sexes' mice submitted to the two-hit model and the participation of oxidative changes in this mechanism. The two-hit consisted of polyI:C administration from postnatal days (PNs) 5-7, and unpredictable stress from PNs35-43. n3-PUFAs were administered from PNs30-60. Prepulse inhibition of the startle reflex (PPI), social interaction, and Y-maze tests were conducted between PNs70-72 to evaluate positive-, negative-, and cognitive-like schizophrenia symptoms. We assessed brain oxidative changes in brain areas and plasma. Both sexes' two-hit mice presented deficits in PPI, social interaction, and working memory that were prevented by n3-PUFAs. In two-hit females, n3-PUFAs prevented increments in nitrite levels in the prefrontal cortex (PFC), hippocampus, striatum, and plasma TBARS levels. In two-hit males, n3-PUFAs prevented the increase in TBARS in the PFC, hippocampus, and striatum. Notably, male mice that received only n3-PUFAs without hit exposure presented impairments in working memory and social interaction. These results add further preclinical evidence for n3-PUFAs as an accessible and effective alternative in preventing behavioral and oxidative changes related to schizophrenia but call attention to the need for precaution in this indication due to hit- and sex-sensitive issues.

Naringin treatment improved main clozapine-induced adverse effects in rats; emphasis on weight gain, metabolic abnormalities, and agranulocytosis

Schizophrenia is one of the major neuropsychiatric disorders affecting people worldwide. Unfortunately, currently available antipsychotic medications possess several side effects. Among them, clozapine is one of the atypical antipsychotics prescribed in schizophrenia wing to its blocking effect on dopamine (D2) and serotonin (5-HT_1c ) receptors. However, it has been recently reserved for resistant schizophrenia due to its several side effects. The current research aimed at investigating potential naringin add-on benefit to cease the main side effects of clozapine in ketamine-induced psychosis in rats. In this study, schizophrenia was induced in rats via ketamine administration that could promote neuropathological patterns of schizophrenia. Afterwards, clozapine and naringin were administered to rats in order to improve such effects induced by ketamine. Clozapine administration promoted weight gain, hyperglycemia, dyslipidemia, and agranulocytosis. However, naringin was able to reduce such adverse effects when added to clozapine treatment. Naringin increased total leukocyte count preventing agranulocytosis either when administered alone or in combination with clozapine. In addition, via its metabolic activities, naringin treatment lowered serum total cholesterol and triglycerides levels. Moreover, naringin prevented weight gain when administered. Finally, naringin reduced serum glucose level preventing hyperglycemia associated with clozapine treatment. Collectively, these findings may suggest that naringin possesses a potential add-on benefit to clozapine in treatment of schizophrenia.

Rapid well-plate assays for motor and social behaviors in larval zebrafish

Behavior phenotypes are a powerful means of uncovering subtle xenobiotic chemical impacts on vertebrate nervous system development. Rodents manifest complex and informative behavior phenotypes but are generally not practical models in which to screen large numbers of chemicals. Zebrafish recapitulate much of the behavioral complexity of higher vertebrates, develop externally and are amenable to assay automation. Short duration automated assays can be leveraged to screen large numbers of chemicals or comprehensive dose-response for fewer chemicals. Here we describe a series of mostly automated assays including larval photomotor response, strobe light response, blue color avoidance, shoaling and mirror stimulus-response performed on the ZebraBox (ViewPoint Behavior Technologies) instrument platform. To explore the sensitivity and uniqueness of each assay endpoint, larval cohorts from 5 to 28 days post fertilization were acutely exposed to several chemicals broadly understood to impact different neuro-activities. We highlight the throughput advantages of using the same instrument platform for multiple assays and the ability of different assays to detect unique phenotypes among different chemicals.

No Impact of Omega-3 Fatty Acid Supplementation on Symptoms or Hostility Among Patients With Schizophrenia

OBJECTIVE

This study was aimed to explore the impact of fish oil (Omega-3 fatty acids) on hostility and psychopathology among patients with acute violent schizophrenia.

METHOD

Sixty seven acute hospitalized patients demonstrating violent behavior in the context of a schizophrenic illness, treated with antipsychotics, were randomly assigned to a supplement with either fish oil (N=32) or placebo (N=35) in a double-blind, placebo-controlled trial. Assessments were conducted at the baseline, week 4 and week 8.

RESULTS

The symptoms and hostility decreased after treatment for 4 and 8 weeks in both groups, with no group differences.

CONCLUSIONS

The current study did not find improvements in symptoms or hostility from the Omega-3 fatty acid supplementation in patients with schizophrenia. The implication is that Omega-3 fatty acids do not reduce psychopathology and hostility in acute patients with schizophrenia.

The Effect of Minor Doses of Olanzapine-Solid Lipid Nanoparticles on an Animal Model of Schizophrenia (Neurochemical and Behavioral Study) and the Side Effect

Background and Objective:

Olanzapine (OLZ) is an atypical psychotic agent; the poor bioavailability of olanzapine is the most important issue in its treatment. The present work was carried out to evaluate the oral form of olanzapine solid lipid nanoparticles (OLZ-SLN) to overcome its poor bioavailability and compare between the effect of different doses of OLZ and OLZ-SLN on ketamineinduced schizophrenic-like symptoms. The study was extended to evaluate the adverse effects of subchronic administration of these doses of OLZ and its SLN.

Methods:

OLZ-SLN was prepared by hot homogenization, particle size, zeta potential and in vitro release and entrapping efficiency studies were performed. In order to assess the effective dose in the treatment of schizophrenia, the effect of different doses of OLZ and OLZ-SLN on open field was assessed and passive avoidance tests were carried out. The test was performed to examine the effects of excitatory and inhibitory amino acids, as well as dopamine and serotonin levels in the brain regions.

Results and Conclusion:

The new oral formula showed high stability and sustained release. The administration of low and high dose of OLZ-SLN equivalent to (1/10 and 1/20 from the therapeutic dose before ketamine attenuated the behavioral abnormalities by blocking the effect of ketamine-induced increase in glutamate, dopamine and serotonin levels and enhanced apoptosis were studied in the brain areas. In addition, the sub-chronic treatment with OLZ-SLN showed no adverse effect while the treatment with OLZ free form did.

The effects of sub-anesthetic ketamine plus ethanol on behaviors and apoptosis in the prefrontal cortex and hippocampus of adolescent rats

Ketamine has become increasingly popular in adolescent drug abusers worldwide. Meanwhile, alcohol is usually used by ketamine users. However, little work has been conducted to examine the chronic combined effects of ketamine and ethanol on adolescent brain. Here we probed into the effects of chronic administration of ketamine at recreational doses alone or combined with ethanol on behaviors and neuron damage in an adolescent rat model. 28-day old rats were treated with either 20 or 30 mg/kg ketamine plus or not plus 10% ethanol daily for 21 days. Depressive like behaviors, anxiety like behavior and memory impairment were tested using open field test, forced swimming test, elevated plus maze and Morris water maze. Apoptosis in prefrontal cortex (PFC) and hippocampus (HIP) were determined by the TdT-mediated dUTP Nick-End Labeling (TUNEL) and protein and mRNA levels of caspase-3, Bax and Bcl-2. Results show that co-application of ketamine and ethanol significantly increased immobility time in the forced swimming test, up-regulated TUNEL positive cells and both protein and mRNA expressions of caspase-3 and Bax, compared with the control group and ketamine and ethanol use alone groups in the PFC, but not in the HIP. Our study suggests that chronic co-administration of ketamine and ethanol results in depressive-like behavior and the caspase-dependent apoptosis in the PFC of adolescent rats' brains.

An increase in plasma brain derived neurotrophic factor levels is related to n-3 polyunsaturated fatty acid efficacy in first episode schizophrenia: secondary outcome analysis of the OFFER randomized clinical trial

RATIONALE

N-3 polyunsaturated fatty acids (n-3 PUFA) influence multiple biochemical mechanisms postulated in the pathogenesis of schizophrenia that may influence BDNF synthesis.

OBJECTIVES

A randomized placebo-controlled study was designed to compare the efficacy of a 26-week intervention composed of either 2.2 g/day of n-3 PUFA or olive oil placebo, with regard to symptom severity in first-episode schizophrenia patients. The secondary outcome measure of the study was to describe the association between n-3 PUFA clinical effect and changes in peripheral BDNF levels.

METHODS

Seventy-one patients aged 16-35 were enrolled in the study and randomly assigned to the following study arms: 36 to the EPA + DHA group and 35 to the placebo group. Plasma BDNF levels were assessed three times, at baseline and at weeks 8 and 26 of the intervention. BDNF levels were determined in plasma samples using Quantikine Human BDNF ELISA kit. Plasma BDNF level changes were further correlated with changes in the severity of symptoms in different clinical domains.

RESULTS

A significantly greater increase in plasma BDNF levels was observed in the intervention compared to the placebo group (Cohen's d = 1.54). Changes of BDNF levels inversely correlated with change in depressive symptoms assessed using the Calgary Depression Rating Scale in Schizophrenia (Pearson's r = - 0.195; p = 0.018).

CONCLUSIONS

The efficacy of a six-month intervention with n-3 PUFA observed in first-episode schizophrenia may be related to an increase in BDNF levels, which may be triggered by the activation of intracellular signaling pathways including transcription factors such as cAMP-reactive element binding protein.

Vinpocetine halts ketamine-induced schizophrenia-like deficits in rats: impact on BDNF and GSK-3β/β-catenin pathway

There are increasing evidences supporting the involvement of oxidative stress and neuroinflammation in schizophrenia. Vinpocetine, a nootropic phosphodiesterase-1 inhibitor, was proven to possess anti-oxidant and anti-inflammatory potentials. This research aimed to reveal the likely protective features of vinpocetine against ketamine-induced schizophrenia-like deficits in rats. Additionally, the probable mechanisms contributing to this neuroprotection were also elucidated. Vinpocetine was given (20 mg/kg, i.p.) once a day for 14 days commencing 7 days before administrating ketamine (25 mg/kg i.p.). Risperidone was applied as a reference antipsychotic. Vinpocetine pre-treatment revealed a marked amendment in the hyperlocomotion, anxiety, and short-term memory deficits induced by ketamine in rats. In rats' hippocampus, ketamine induced a drastic increase in tissue levels of dopamine, lipid peroxidation, and pro-inflammatory cytokines along with a significant decrease in glutamate, GABA, SOD, and total anti-oxidant capacity. Also, ketamine induced a reduced level of BDNF together with the potentiation of GSK-3β/β-catenin pathway that led to the destruction of β-catenin. Pre-treatment of ketamine-challenged animals with vinpocetine significantly attenuated oxidative stress, inflammation, and neurotransmitter alterations. Vinpocetine also elevated BDNF expression and prevented ketamine-induced stimulation of the GSK-3β/β-catenin signaling. This research presents enlightenments into the role of vinpocetine in schizophrenia. This role may be accomplished through its effect on oxidative stress, inflammation as well as modulating BDNF and the GSK-3β/β-catenin pathway.

Effects of Omega-3 in the treatment of violent schizophrenia patients

OBJECTIVE

This study was designed to explore the relationship in between the daily consumption of fish oil (360mg DHA+540mg EPA), and reduction of symptoms and violent behavior among patients with schizophrenia.

METHOD

Fifty inpatients meeting ICD-10 criteria for schizophrenia and scoring more than four of Modified Overt Aggression Scale (MOAS) with antipsychotics treatment were randomly assigned to receive either fish oil (N=28) or a placebo (N=22) in a twelve week, double-blind supplementation trial. Assessments were performed at baseline and at weeks 4, 8 and 12.

RESULTS

The PANSS and CGI scores decreased at the week of 4, 8 and 12, but no differences were found between the two groups. MOAS scores declined significantly at weeks 4, 8 and 12. At week 12, MOAS scores of the fish oil group declined significantly than the placebo group (t=-2.40, P<0.05).

CONCLUSIONS

violent schizophrenia patients treated with fish oil (360mg DHA+540mg EPA) demonstrated a decrease in violence, but improvement in positive and negative symptoms was no greater than patients treated with the placebo after twelve weeks.

The use of antioxidant compounds in the treatment of first psychotic episode: Highlights from preclinical studies

Recent evidence highlighted a pathogenetic link between redox dysregulation and the early stages of psychosis. Indeed, an increasing number of studies have pointed toward an association between oxidative stress, both at central and peripheral levels, and first psychotic episode. Moreover, basal low antioxidant capacity has been shown to directly correlate with cognitive impairment in the early onset of psychosis. In this context, the possibility to use antioxidant compounds in first psychotic episode, especially as supplementation to antipsychotic therapy, has become the focus of numerous investigations on rodents with the aim to translate data on the possible effects of antioxidant therapies to large populations of patients, with a diagnosis of the first psychotic episode. In this review, we will discuss studies, published from January 1st, 2007 to July 31st, 2017, investigating the effects of antioxidant compounds on neuropathological alterations observed in different rodent models characterized by a cluster of psychotic-like symptoms reminiscent of what observed in human first psychotic episode. A final focus on the effective possibility to directly translate data obtained on rodents to humans will be also provided.

N-3 (Omega-3) Fatty Acids: Effects on Brain Dopamine Systems and Potential Role in the Etiology and Treatment of Neuropsychiatric Disorders

BACKGROUND & OBJECTIVE

A number of neuropsychiatric disorders, including Parkinson's disease, schizophrenia, attention deficit hyperactivity disorder, and, to some extent, depression, involve dysregulation of the brain dopamine systems. The etiology of these diseases is multifactorial, involving genetic and environmental factors. Evidence suggests that inadequate levels of n-3 (omega- 3) polyunsaturated fatty acids (PUFA) in the brain may represent a risk factor for these disorders. These fatty acids, which are derived from the diet, are a major component of neuronal membranes and are of particular importance in brain development and function. Low levels of n-3 PUFAs in the brain affect the brain dopamine systems and, when combined with appropriate genetic and other factors, increase the risk of developing these disorders and/or the severity of the disease. This article reviews the neurobiology of n-3 PUFAs and their effects on dopaminergic function.

CONCLUSION

Clinical studies supporting their role in the etiologies of diseases involving the brain dopamine systems and the potential of n-3 PUFAs in the treatment of these disorders are discussed.

Differences in omega-3 and omega-6 polyunsaturated fatty acid consumption in people at ultra-high risk of psychosis, first-episode schizophrenia, and in healthy controls

AIM

Supplementation with omega-3 PUFA showed efficacy in reducing the risk of transition into psychosis in UHR individuals. It is uncertain whether dietary patterns can be partly responsible for n-3 deficiencies observed in susceptible participants before the diagnosis of schizophrenia. The study was designed to assess differences in omega-3 and omega-6 PUFA consumption in healthy controls (HC), UHR participants and FES patients as well as to verify the hypothesis that dietary changes in PUFA consumption are present before active psychosis develops, that is, in UHR individuals.

METHODS

Dietary habits during the previous year were assessed in 34 patients at UHR of psychosis, 33 patients diagnosed with FES and 33 HC participants using a validated Food-Frequency Questionnaire and the Polish Food Composition Tables.

RESULTS

Significant differences in omega-3 and omega-6 PUFA intake were observed between study groups. UHR and FES groups reported significantly higher consumption of omega-6 PUFA in comparison with HC. FES patients also reported a higher consumption of alpha-linolenic acid (omega-3) in comparison with HC. No significant differences were seen in consumption of long-chain marine PUFA.

CONCLUSIONS

Differences in omega-6 and omega-3 PUFA consumption exist before development of psychotic symptoms, fulfilling the criteria of schizophrenia.

Effects of omega-3 PUFA on immune markers in adolescent individuals at ultra-high risk for psychosis - Results of the randomized controlled Vienna omega-3 study

Alterations of immune function have been reported in ultra-high risk (UHR) for psychosis patients causing expectations in terms of predictive meaningfulness and benefits of anti-inflammatory agents. According to a RCT in UHR-patients supplementation of omega-3 polyunsaturated fatty acids (PUFA) was effective in reducing transition to psychosis risk and to improve symptomatology. Based on preclinical findings, we now investigated state marker properties of and the influence of PUFA on immune markers in a RCT (clinical trials.gov Identifier: NCT00396643). In a longitudinal design we measured plasma levels of the pro-inflammatory interleukin 6 (IL-6), the soluble alpha (Tac) subunit of the interleukin 2 receptor (sIL-2r), and the circulating soluble form of the intercellular adhesion molecule one (sICAM-1), in 79 help-seeking UHR individuals (13-25years of age). Using linear mixed model (LMM) analysis, we investigated the effects of 12weeks supplementation of either 1.2g/d PUFA (n=38) or Placebo (n=41). At baseline, inflammatory markers were not altered in patients who later suffered transition to psychosis within one year (n=12; 11 PUFA-group, 1 PL-group). IL-6 was weakly inverse associated with omega-6 PUFA, and highly increased in nicotine users. In univariate tests of the LMM omega-3 PUFA caused a significant increase of sICAM-1 (p=0.022). PUFA did not significantly influence IL-6 or sIL-2r. The enhancement of sICAM-1 in the PUFA condition is suggestive for supportive effects on vascular immune response and immediate Th1 helper cell mediated immune answer, which was found disturbed in manifest schizophrenia, e.g. by facilitating the leukocyte adhesion and migration across the endothelium.

Comparative effects of sertraline, haloperidol or olanzapine treatments on ketamine-induced changes in mouse behaviours

Effects of sertraline, haloperidol or olanzapine administration on ketamine-induced behaviours in mice were examined. The aim was to ascertain the degree of reversal of such behaviours by sertraline, and compare its effectiveness to haloperidol and olanzapine. Ten-week old mice (N = 120) were equally divided into main groups; 1 (open-field, radial-arm maze and elevated plus maze {EPM} tests), and 2 (social interaction test). Mice in each main group were assigned into six groups of ten (n = 10) each. Group 1 received intraperitoneal (i.p) injection of vehicle, while groups 2-6 received i.p ketamine at 15 mg/kg daily for 10 days. From day 11 to 24, mice in group 1 (vehicle) were given distilled water (i.p at 2 ml/kg and oral at 10 ml/kg), group 2 (ketamine control) received daily i.p ketamine and oral distilled water; while animals in groups 3-6 received daily i.p. ketamine and oral haloperidol (4 mg/kg), olanzapine (2 mg/kg), or one of two doses of sertraline (SERT) (2.5 or 5 mg/kg), respectively. Treatments were administered daily, and behaviours assessed on days 11 and 24. Results showed that repeated ketamine administration caused hyperlocomotion, increased self-grooming, memory loss and social withdrawal. Administration of sertraline (both doses), haloperidol, and olanzapine reversed ketamine-induced behavioural changes. However, in the EPM, sertraline and olanzapine were anxiolytic, while haloperidol was anxiogenic. Sertraline's effect on behaviours tested was comparable to olanzapine and better than haloperidol. In conclusion, this study shows that sertraline's ability to counteract ketamine-induced behavioural changes in mice is comparable to known antipsychotics.

The preventive effects of ascorbic acid supplementation on locomotor and acetylcholinesterase activity in an animal model of schizophrenia induced by ketamine

Studies have shown that schizophrenic patients seem to have nutritional deficiencies. Ascorbic acid (AA) has an important antioxidant effect and neuromodulatory properties. The aim of this study was to evaluate the effects of AA on locomotor activity and the acetylcholinesterase activity (AChE) in an animal model of schizophrenia (SZ). Rats were supplemented with AA (0.1, 1, or 10 mg/kg), or water for 14 days (gavage). Between the 9th and 15th days, the animals received Ketamine (Ket) (25 mg/kg) or saline (i.p). After the last administration (30 min) rats were subjected to the behavioral test. Brain structures were dissected for biochemical analysis. There was a significant increase in the locomotor activity in Ket treated. AA prevented the hyperlocomotion induced by ket. Ket also showed an increase of AChE activity within the prefrontal cortex and striatum prevented by AA. Our data indicates an effect for AA in preventing alterations induced by Ket in an animal model of SZ, suggesting that it may be an adjuvant approach for the development of new therapeutic strategies within this psychiatric disorder.

Omega-3 fatty acids and mood stabilizers alter behavioral and oxidative stress parameters in animals subjected to fenproporex administration

Studies have shown that oxidative stress is involved in the pathophysiology of bipolar disorder (BD). It is suggested that omega-3 (ω3) fatty acids are fundamental to maintaining the functional integrity of the central nervous system. The animal model used in this study displayed fenproporex-induced hyperactivity, a symptom similar to manic BD. Our results showed that the administration of fenproporex, in the prevent treatment protocol, increased lipid peroxidation in the prefrontal cortex (143%), hippocampus (58%) and striatum (181%), and ω3 fatty acids alone prevented this change in the prefrontal cortex and hippocampus, whereas the co-administration of ω3 fatty acids with VPA prevented the lipoperoxidation in all analyzed brain areas, and the co-administration of ω3 fatty acids with Li prevented this increase only in the prefrontal cortex and striatum. Moreover, superoxide dismutase (SOD) activity was decreased in the striatum (54%) in the prevention treatment, and the administration of ω3 fatty acids alone or in combination with Li and VPA partially prevented this inhibition. On the other hand, in the reversal treatment protocol, the administration of fenproporex increased carbonyl content in the prefrontal cortex (25%), hippocampus (114%) and striatum (91%), and in prefrontal coxter the administration of ω3 fatty acids alone or in combination with Li and VPA reversed this change, whereas in the hippocampus and striatum only ω3 fatty acids alone or in combination with VPA reversed this effect. Additionally, the administration of fenproporex resulted in a marked increase of TBARS in the hippocampus and striatum, and ω3 fatty acids alone or in combination with Li and VPA reversed this change. Finally, fenproporex administration decreased SOD activity in the prefrontal cortex (85%), hippocampus (52%) and striatum (76%), and the ω3 fatty acids in combination with VPA reversed this change in the prefrontal cortex and striatum, while the co-administration of ω3 fatty acids with Li reversed this inhibition in the hippocampus and striatum. In conclusion, our results support other studies showing the importance of ω3 fatty acids in the brain and the potential for these fatty acids to aid in the treatment of BD.

Omega-3 fatty acids in schizophrenia Part II: Clinical applications

Ω-3 unsaturated fatty acids are compounds belonging to the group of essential fatty acids (EFAs). The history of the discovery of EFAs dates back to the 1930s of the twentieth century, however, growing interest in ω-3 EFAs in the context of mental health has been observed since the year 2000. In view of their multidirectional action, these compounds are a promising form of adjunctive therapy of many illnesses, including psychiatric disorders. The present article aims to review the literature on the clinical applicability of ω-3 EFAs in treating schizophrenia. We present the results of preclinical studies in this area and the mechanisms of ω-3 EFAs action discussed by the authors. The randomized controlled trials (RCTs) evaluating the possibility of using ω-3 EFAs in schizophrenia are characterized in detail. The results of the tests are not clear, which may result from the methodological diversity of interventions made. Ω-3 EFAs seem to be a promising form of adjunctive therapy of schizophrenia. Further research is needed, which will allow for defining groups of patients in which intervention will bring the expected results.

Effect of folic acid on oxidative stress and behavioral changes in the animal model of schizophrenia induced by ketamine

Recent studies have shown benefits for the supplementation of folic acid in schizophrenic patients. The aim of this study was to evaluate the effects of folic acid addition on adult rats, over a period of 7 or 14 days. It also sets out to verify any potential protective action using an animal model of schizophrenia induced by ketamine, in behavioral and biochemical parameters. This study used two protocols (acute and chronic) for the administration of ketamine at a dose of 25 mg/kg (i.p.). The folic acid was given by oral route in doses of 5, 10 and 50 mg/kg, once daily, for 7 and/or 14 days in order to compare the protective effects of folic acid. Thirty minutes after the last administration of ketamine, the locomotor and social interaction activities were evaluated, and immediately the brain structure were removed for biochemical analysis. In this study, ketamine was administered in a single dose or in doses over the course of 7 days increasing the animal's locomotion. This study showed that the administration of folic acid over 7 days was unable to prevent hyper locomotion. In contrast, folic acid (10 and 50 mg/kg) administrated over a period of 14 days, was able to partially prevent the hyper locomotion. Our data indicates that both acute and chronic administrations of ketamine increased the time to first contact between the animals, while the increased latency for social contact was completely prevented by folic acid (5, 10 and 50 mg/kg). Chronic and acute administrations of ketamine also increased lipid peroxidation and protein carbonylation in brain. Folic acid (10 and 50 mg/kg) supplements showed protective effects on the oxidative damage found in the different brain structures evaluated. All together, the results indicate that nutritional supplementation with folic acid provides promising results in an animal model of schizophrenia induced by ketamine.

Differential expression of the inflammation marker IL12p40 in the at-risk mental state for psychosis: a predictor of transition to psychotic disorder?

BACKGROUND

The identification of biomarkers of transition from the at-risk mental state (ARMS) to psychotic disorder is important because early treatment of psychosis is associated with improved outcome. Increasing evidence points to an inflammatory contribution to psychosis. We questioned whether raised levels of plasma inflammatory markers predict transition from ARMS to psychotic disorder and whether any such predictors could be reduced by omega-3 (ω-3) polyunsaturated fatty acids (PUFAs).

METHODS

We measured the levels of 40 neuroinflammation biomarkers using a commercially available immunoassay kit. Firstly, we compared inflammatory markers in subjects in the ARMS who transitioned to psychotic disorder (n = 11) compared to subjects who did not (n = 28). Then we compared inflammatory markers in all subjects before and after ω-3 PUFA treatment (n = 40).

RESULTS

Our data provides preliminary evidence that elevations in the baseline plasma levels of the inflammatory marker IL12/IL23p40 are associated with transition from ARMS to psychotic disorder. IL12/IL23p40 levels did not change following 12 weeks administration of ω-3 PUFAs. These findings provide evidence that elevated plasma IL12/IL23p40 is a potential biomarker of increased risk for transition to psychotic disorder.

CONCLUSION

Further studies are required to confirm and extend this finding. Our results do not provide support for the possibility that administration of ω-3 PUFAs act to reduced transition to psychotic disorder by reducing blood levels of IL12/IL23p40.

TRIAL REGISTRATION

ClinicalTrials.gov, a service of the U.S. National Institutes of Health, Identifier: NCT00396643 , last updated December 20, 2007. Retrospectively registered.

The Gut-Brain Axis, BDNF, NMDA and CNS Disorders

Gastro-intestinal (GI) microbiota and the 'gut-brain axis' are proving to be increasingly relevant to early brain development and the emergence of psychiatric disorders. This review focuses on the influence of the GI tract on Brain-Derived Neurotrophic Factor (BDNF) and its relationship with receptors for N-methyl-D-aspartate (NMDAR), as these are believed to be involved in synaptic plasticity and cognitive function. NMDAR may be associated with the development of schizophrenia and a range of other psychopathologies including neurodegenerative disorders, depression and dementias. An analysis of the routes and mechanisms by which the GI microbiota contribute to the pathophysiology of BDNF-induced NMDAR dysfunction could yield new insights relevant to developing novel therapeutics for schizophrenia and related disorders. In the absence of GI microbes, central BDNF levels are reduced and this inhibits the maintenance of NMDAR production. A reduction of NMDAR input onto GABA inhibitory interneurons causes disinhibition of glutamatergic output which disrupts the central signal-to-noise ratio and leads to aberrant synaptic behaviour and cognitive deficits. Gut microbiota can modulate BDNF function in the CNS, via changes in neurotransmitter function by affecting modulatory mechanisms such as the kynurenine pathway, or by changes in the availability and actions of short chain fatty acids (SCFAs) in the brain. Interrupting these cycles by inducing changes in the gut microbiota using probiotics, prebiotics or antimicrobial drugs has been found promising as a preventative or therapeutic measure to counteract behavioural deficits and these may be useful to supplement the actions of drugs in the treatment of CNS disorders.

Different dosing regimens of repeated ketamine administration have opposite effects on novelty processing in rats

Repeated exposure to sub-anesthetic doses of ketamine in rats has been shown to induce cognitive deficits, as well as behavioral changes akin to the negative symptoms of schizophrenia, giving much face validity to the use of ketamine administration as a pharmacological model of schizophrenia. This study sought to further characterize the behavioral effects of two different ketamine pre-treatment regimens, focusing primarily on the effects of repeated ketamine administration on novelty processing, a capacity that is disrupted in schizophrenia. Rats received 5 or 14 intra-peritoneal injections of 30mg/kg ketamine or saline across 5 or 7days, respectively. They were then tested in an associative mismatch detection task to examine their ability to detect novel configurations of familiar audio-visual sequences. Furthermore, rats underwent a sequential novel object and novel object location exploration task. Subsequently, rats were also tested on the delayed matching to place T-maze task, sucrose preference task and locomotor tests involving administering a challenge dose of amphetamine (AMPH). The high-dose ketamine pre-treatment regimen elicited impairments in mismatch detection and working memory. In contrast, the low-dose ketamine pre-treatment regimen improved performance of novelty detection. In addition, low-dose ketamine pre-treated rats showed locomotor sensitization following an AMPH challenge, while the high-dose ketamine pre-treated rats showed an attenuated locomotor response to AMPH, compared to control rats. These findings demonstrate that different regimens of repeated ketamine administration induce alterations in novelty processing in opposite directions, and that differential neural adaptations occurring in the mesolimbic dopamine system may underlie these effects.

Omega 3 Fatty Acids: Novel Neurotherapeutic Targets for Cognitive Dysfunction in Mood Disorders and Schizophrenia?

An increasing body of evidences from preclinical as well as epidemiological and clinical studies suggest a potential beneficial role of dietary intake of omega-3 fatty acids for cognitive functioning. In this narrative review, we will summarize and discuss recent findings from epidemiological, interventional and experimental studies linking dietary consumption of omega-3 fatty acids to cognitive function in healthy adults. Furthermore, affective disorders and schizophrenia (SZ) are characterized by cognitive dysfunction encompassing several domains. Cognitive dysfunction is closely related to impaired functioning and quality of life across these conditions. Therefore, the current review focues on the potential influence of omega-3 fatty acids on cognition in SZ and affective disorders. In sum, current data predominantly from mechanistic models and animal studies suggest that adjunctive omega-3 fatty acid supplementation could lead to improved cognitive functioning in SZ and affective disorders. However, besides its translational promise, evidence for clinical benefits in humans has been mixed. Notwithstanding evidences indicate that adjunctive omega-3 fatty acids may have benefit for affective symptoms in both unipolar and bipolar depression, to date no randomized controlled trial had evaluated omega-3 as cognitive enhancer for mood disorders, while a single published controlled trial suggested no therapeutic benefit for cognitive improvement in SZ. Considering the pleiotropic mechanisms of action of omega-3 fatty acids, the design of well-designed controlled trials of omega-3 supplementation as a novel, domain-specific, target for cognitive impairment in SZ and affective disorders is warranted.

Omega-3 Fatty Acids and Mood Stabilizers Alter Behavioural and Energy Metabolism Parameters in Animals Subjected to an Animal Model of Mania Induced by Fenproporex

Studies have shown that changes in energy metabolism are involved in the pathophysiology of bipolar disorder (BD). It was suggested that omega-3 (ω3) fatty acids have beneficial properties in the central nervous system and that this fatty acid plays an important role in energy metabolism. Therefore, the study aimed to evaluate the effect of ω3 fatty acids alone and in combination with lithium (Li) or valproate (VPA) on behaviour and parameters of energy metabolism in an animal model of mania induced by fenproporex. Our results showed that co-administration of ω3 fatty acids and Li was able to prevent and reverse the increase in locomotor and exploratory activity induced by fenproporex. The combination of ω3 fatty acids with VPA was only able to prevent the fenproporex-induced hyperactivity. For the energy metabolism parameters, our results showed that the administration of Fen for the reversal or prevention protocol inhibited the activities of succinate dehydrogenase, complex II and complex IV in the hippocampus. However, hippocampal creatine kinase (CK) activity was decreased only for the reversal protocol. The ω3 fatty acids, alone and in combination with VPA or Li, prevented and reversed the decrease in complex II, IV and succinate dehydrogenase activity, whereas the decrease in CK activity was only reversed after the co-administration of ω3 fatty acids and VPA. In conclusion, our results showed that the ω3 fatty acids combined with VPA or Li were able to prevent and reverse manic-like hyperactivity and the inhibition of energy metabolism in the hippocampus, suggesting that ω3 fatty acids may play an important role in the modulation of behavioural parameters and energy metabolism.

The association between polyunsaturated fatty acid consumption and the transition to psychosis in ultra-high risk individuals

PUFA deficiencies in cellular membranes have been observed in ultra-high risk (HR) individuals and in early schizophrenia. It is uncertain whether dietary PUFA consumption can be associated with the risk of transition to psychosis in HR individuals. The aim of the study was to assess PUFA consumption and confirm whether dietary habits are related to the risk of transition to full-threshold psychosis in HR individuals during a 12-month follow-up. PUFA consumption during the previous year was analyzed in 62 h individuals and 33 healthy controls (HC) at the beginning of the follow-up period using a validated Food-Frequency Questionnaire and the Polish Food Composition Tables. Fifteen HR individuals converted into psychosis (C-HR) during the 12-month follow-up. C-HR individuals reported significantly higher consumption of n-6 fatty acids (linoleic acid, LA and arachidonic acid, AA) in comparison with individuals who did not develop psychosis (NC-HR). The C-HR group reported a significantly higher AA/(EPA+DHA) consumption ratio than the NC-HR group. HC reported significantly higher consumption of most n-3 PUFA and lower consumption of all n-6 PUFA than both groups of HR individuals. The results suggest that dietary patterns of PUFA consumption may play a role in the conversion to psychosis of HR individuals.

Altering the course of schizophrenia: progress and perspectives

Despite a lack of recent progress in the treatment of schizophrenia, our understanding of its genetic and environmental causes has considerably improved, and their relationship to aberrant patterns of neurodevelopment has become clearer. This raises the possibility that 'disease-modifying' strategies could alter the course to - and of - this debilitating disorder, rather than simply alleviating symptoms. A promising window for course-altering intervention is around the time of the first episode of psychosis, especially in young people at risk of transition to schizophrenia. Indeed, studies performed in both individuals at risk of developing schizophrenia and rodent models for schizophrenia suggest that pre-diagnostic pharmacotherapy and psychosocial or cognitive-behavioural interventions can delay or moderate the emergence of psychosis. Of particular interest are 'hybrid' strategies that both relieve presenting symptoms and reduce the risk of transition to schizophrenia or another psychiatric disorder. This Review aims to provide a broad-based consideration of the challenges and opportunities inherent in efforts to alter the course of schizophrenia.

Behavioural effects of high fat diet in a mutant mouse model for the schizophrenia risk gene neuregulin 1

Schizophrenia patients are often obese or overweight and poor dietary choices appear to be a factor in this phenomenon. Poor diet has been found to have complex consequences for the mental state of patients. Thus, this study investigated whether an unhealthy diet [i.e. high fat diet (HFD)] impacts on the behaviour of a genetic mouse model for the schizophrenia risk gene neuregulin 1 (i.e. transmembrane domain Nrg1 mutant mice: Nrg1 HET). Female Nrg1 HET and wild-type-like littermates (WT) were fed with either HFD or a control chow diet. The mice were tested for baseline (e.g. anxiety) and schizophrenia-relevant behaviours after 7 weeks of diet exposure. HFD increased body weight and impaired glucose tolerance in all mice. Only Nrg1 females on HFD displayed a hyper-locomotive phenotype as locomotion-suppressive effects of HFD were only evident in WT mice. HFD also induced an anxiety-like response and increased freezing in the context and the cued version of the fear conditioning task. Importantly, CHOW-fed Nrg1 females displayed impaired social recognition memory, which was absent in HFD-fed mutants. Sensorimotor gating deficits of Nrg1 females were not affected by diet. In summary, HFD had complex effects on the behavioural phenotype of test mice and attenuated particular cognitive deficits of Nrg1 mutant females. This topic requires further investigations thereby also considering other dietary factors of relevance for schizophrenia as well as interactive effects of diet with medication and sex.

A randomized controlled study of the efficacy of six-month supplementation with concentrated fish oil rich in omega-3 polyunsaturated fatty acids in first episode schizophrenia

Short-term clinical trials of omega-3 polyunsaturated fatty acids (n-3 PUFA) as add-on therapy in patients with schizophrenia revealed mixed results. The majority of these studies used an 8- to 12-week intervention based on ethyl-eicosapentaenoic acid. A randomized placebo-controlled trial was designed to compare the efficacy of 26-week intervention, composed of either 2.2 g/day of n-3 PUFA, or olive oil placebo, with regard to symptom severity in first-episode schizophrenia patients. Seventy-one patients (aged 16-35) were enrolled in the study and randomly assigned to the study arms. The primary outcome measure of the clinical evaluation was schizophrenia symptom severity change measured by the Positive and Negative Syndrome Scale (PANSS). Mixed models repeated measures analysis revealed significant differences between the study arms regarding total PANSS score change favouring n-3 PUFA (p = 0.016; effect size (ES) = 0.29). A fifty-percent improvement in symptom severity was achieved significantly more frequently in the n-3 PUFA group than in the placebo group (69.4 vs 40.0%; p = 0.017). N-3 PUFA intervention was also associated with an improvement in general psychopathology, measured by means of PANSS (p = 0.009; ES = 0.32), depressive symptoms (p = 0.006; ES = 0.34), the level of functioning (p = 0.01; ES = 0.31) and clinical global impression (p = 0.046; ES = 0.29). The findings suggest that 6-month intervention with n-3 PUFA may be a valuable add-on therapy able to decrease the intensity of symptoms and improve the level of functioning in first-episode schizophrenia patients.

The Antipsychotic Effects of Omega-3 Fatty Acids in Rats

BACKGROUND

In humans, omega-3 fatty acids are necessary for cell membranes, brain function and nerve transmission continuation. When animals are exposed to a new environment-or as a result of an apomorphine application that creates an agonistic effect on D1 and D2 receptors-they display behavioral reactions like rearing and stereotypy. This study aims to reveal the possible antipsychotic and oxidative effects of omega-3 fatty acids by comparing with chlorpromazine, a conventional antipsychotic drug, through evaluating the novelty-induced rearing and apomorphine-induced stereotypic behaviors, as well as malondialdehyde and glutathione levels in rats.

METHODS

Twenty-eight, adult, male, Wistar rats were used in the study. Briefly, 4 groups of rats (n = 7) were administered docosahexaenoic acid (DHA) + eicosapentaenoic acid (EPA) (300 mg/kg; DHA: 120 mg/kg + EPA: 180 mg/kg intraperitoneally [IP]), DHA + EPA (150 mg/kg; DHA: 60 mg/kg + EPA: 90 mg/kg IP), chlorpromazine (1 mg/kg, IP) and isotonic saline (1 mL/kg, IP). One hour later, apomorphine (2 mg/kg, subcutaneously) was administered to each rat. After the apomorphine administration, rats were observed for stereotypic behavior.

RESULTS

This study shows that omega-3 fatty acids, "similar to antipsychotics," reversed the psychotic like effects, increase of oxidants and decrease of antioxidants that are composed experimentally in rats.

CONCLUSIONS

The application of omega-3 fatty acids has antipsychotic effects and causes an oxidative imbalance. This study adds new evidence to the current literature regarding the possible antipsychotic effects of omega-3 fatty acids.

Beneficial effects of omega-3 fatty acids and vitamin B12 supplementation on brain docosahexaenoic acid, brain derived neurotrophic factor, and cognitive performance in the second-generation Wistar rats

In vegetarian population, vitamin B12 deficiency coexists with suboptimal levels of omega-3 fatty acids. Studies indicate a need for supplementation/fortification of vitamin B12 and omega-3 fatty acids to reduce the risk of brain disorders. We have described the effects of vitamin B12 and omega-3 fatty acid supplementation on brain development in F1 generation animals. The current study investigates the effects of vitamin B12 and omega-3 fatty acids supplementation on brain function and cognition. Pregnant Wistar rats were assigned the following groups: control, vitamin B12 deficient (BD), vitamin B12 deficient + omega-3 fatty acid (BDO), vitamin B12 supplemented (BS), vitamin B12 supplemented + omega-3 fatty acid (BSO). The same diets were continued for two generations. BDO group showed higher (P < 0.05) levels of BDNF (brain derived neurotrophic factor) and DHA (docosahexaenoic acid) in the cortex and hippocampus as compared with the BD group. The cognitive performance was also normalized in this group. BS showed comparable levels of DHA, BDNF (protein and mRNA), and CREB mRNA (cAMP response element-binding protein) to that of control group while Tropomyosin receptor kinase mRNA levels were higher. The combined vitamin B12 and omega-3 fatty acid supplementation further enhanced the levels of DHA (P < 0.05) and BDNF (P < 0.05) in the hippocampus and CREB mRNA (P < 0.01) in the cortex as compared with BS group. The cognitive performance of these animals was higher (P < 0.05) as compared with BS group. Our data indicates the beneficial effects of vitamin B12 and omega-3 fatty acid supplementation across two generations on brain development and function.

Alpha-lipoic acid alone and combined with clozapine reverses schizophrenia-like symptoms induced by ketamine in mice: Participation of antioxidant, nitrergic and neurotrophic mechanisms

Oxidative stress has important implications in schizophrenia. Alpha-lipoic acid (ALA) is a natural antioxidant synthesized in human tissues with clinical uses. We studied the effect of ALA or clozapine (CLZ) alone or in combination in the reversal of schizophrenia-like alterations induced by ketamine (KET). Adult male mice received saline or KET for 14 days. From 8th to 14th days mice were additionally administered saline, ALA (100 mg/kg), CLZ 2.5 or 5 mg/kg or the combinations ALA+CLZ2.5 or ALA+CLZ5. Schizophrenia-like symptoms were evaluated by prepulse inhibition of the startle (PPI) and locomotor activity (positive-like), social preference (negative-like) and Y maze (cognitive-like). Oxidative alterations (reduced glutathione - GSH and lipid peroxidation - LP) and nitrite in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST) and BDNF in the PFC were also determined. KET caused deficits in PPI, working memory, social interaction and hyperlocomotion. Decreased levels of GSH, nitrite (HC) and BDNF and increased LP were also observed in KET-treated mice. ALA and CLZ alone reversed KET-induced behavioral alterations. These drugs also reversed the decreases in GSH (HC) and BDNF and increase in LP (PFC, HC and ST). The combination ALA+CLZ2.5 reversed behavioral and some neurochemical parameters. However, ALA+CLZ5 caused motor impairment. Therefore, ALA presented an antipsychotic-like profile reversing KET-induced positive- and negative-like symptoms. The mechanism partially involves antioxidant, neurotrophic and nitrergic pathways. The combination of ALA+CLZ2.5 improved most of the parameters evaluated in this study without causing motor impairment demonstrating, thus, that possibly when combined with ALA a lower dose of CLZ is required.

Brain-derived neurotrophic factor (BDNF) and neurocognitive deficits in people with schizophrenia: a meta-analysis

Studies suggest that the BDNF Val66Met (rs6265) polymorphism is associated with the incidence of schizophrenia and neurocognitive functioning. These associations appear to be however somewhat mixed. We conducted two separate meta-analyses to investigate (1) the association between the Val66Met polymorphism and neurocognition in people with schizophrenia and (2) the association between peripheral expression of BDNF and neurocognitive phenotypes. For the first aim, we identified 12 studies and 67 comparisons of Met allele carriers and Val homozygotes. These comparisons included 1890 people with schizophrenia (men=1465, women=553), of whom 972 were Met allele carriers and 918 were Val homozygotes. For the second aim, we identified five studies and 25 correlations of peripheral BDNF and neurocognitive scores. The meta-analysis for the second aim included 414 people with schizophrenia (men=292, women=170). First, we found non-significant difference between the genotype groups on most neurocognitive domains. Second, correlations between peripheral BDNF and neurocognitive phenotypes were minimal but we obtained significant effects for the reasoning and problem-solving domains; thus, higher levels of BDNF expression corresponded to better performance on reasoning/problem-solving tasks. The meta-analyses did not robustly establish an association between BDNF Val66Met polymorphism and neurocognition in schizophrenia.

Adult emotionality and neural plasticity as a function of adolescent nutrient supplementation in male rats

The present study explored the effects of supplementing male rats with either choline, omega-3 fatty acids, or phytoestrogens, from weaning into early adulthood, on emotionality and hippocampal plasticity. Because of the neuroprotective properties of these nutrients, we hypothesized that they would positively affect both behavior and hippocampal function when compared to non-supplemented control rats. To test this hypothesis, male Sprague Dawley rats were assigned to one of four nutrient conditions after weaning: 1) control (normal rat chow); 2) choline (supplemented in drinking water); 3) omega 3 fatty acids (daily oral supplements); or 4) phytoestrogens (supplemented in chow). After 4weeks on their respective diets, a subset of rats began 3weeks of behavioral testing, while the remaining behaviorally naïve rats were sacrificed after 6weeks on the diets to assess numbers of adult-born hippocampal neurons using the immature neuron marker, doublecortin. The results revealed that choline supplementation affected emotional functioning; compared to rats in other diet conditions, rats in this group were less anxious in an open field and after exposure to predator odor and showed less behavioral despair after forced swimming. Similar behavioral findings were evident following supplementation with omega-3 fatty acids and phytoestrogen supplementation, though not on all tests and not to the same magnitude. Histological findings followed a pattern consistent with the behavioral findings: choline supplementation, followed by omega-3 fatty acid supplementation, but not phytoestrogen supplementation, significantly increased the numbers of new-born hippocampal neurons. Choline and omega-3 fatty acids have similar biological functions-affecting cell membranes, growth factor levels, and epigenetically altering gene transcription. Thus, the present findings suggest that targeting nutrients with these effects may be a viable strategy to combat adult psychopathologies.

Effect of sepsis on behavioral changes on the ketamine-induced animal model of schizophrenia

This study aimed to evaluate the effect of sepsis on behavioral changes on the ketamine-induced animal model of schizophrenia. Male Wistar rats underwent Cecal Ligation and Perporation (CLP) with "basic support" or were sham-operated. After 30 days, the animals were submitted to a model of schizophrenia by injection of Ketamine. The behavior tests were performed after 30 min of the injection of Ketamine or saline. Ketamine in doses of 15 and 25mg/kg increased locomotor activity, latency to first contact in the social interaction and stereotyped behavior. Some changes caused by sepsis may be associated with a predisposition to develop schizophrenia in the animal model.

Omega-3 fatty acids prevent the ketamine-induced increase in acetylcholinesterase activity in an animal model of schizophrenia

AIMS

Schizophrenia is a debilitating neurodevelopmental disorder that is associated with dysfunction in the cholinergic system. Early prevention is a target of treatment to improve long-term outcomes. Therefore, we evaluated the preventive effects of omega-3 fatty acids on AChE activity in the prefrontal cortex, hippocampus and striatum in an animal model of schizophrenia.

MAIN METHODS

Young Wistar rats (30 days old) were initially treated with omega-3 fatty acids or vehicle alone. Animals received ketamine to induce an animal model of schizophrenia or saline plus omega-3 fatty acids or vehicle alone for 7 consecutive days beginning on day 15. A total of 22 days elapsed between the treatment and intervention. Animals were sacrificed, and brain structures were dissected to evaluate AChE activity and gene expression.

KEY FINDINGS

Our results demonstrate that ketamine increased AChE activity in these three structures, and omega-3 fatty acids plus ketamine showed lower values for the studied parameters, which indicate a partial preventive mechanism of omega-3 fatty acid supplementation. We observed no effect on AChE expression. Together, these results indicate that omega-3 fatty acid supplementation effectively reduced AChE activity in an animal model of schizophrenia in all studied structures. In conclusion, the present study provides evidence that ketamine and omega-3 fatty acids affect the cholinergic system, and this effect may be associated with the physiopathology of schizophrenia. Further studies are required to investigate the mechanisms that are associated with this effect.

Relationship between membrane fatty acids and cognitive symptoms and information processing in individuals at ultra-high risk for psychosis

Cognitive symptoms and impairment are central to schizophrenia and often an early sign of this condition. The present study investigated biological correlates of cognitive symptoms and performance in individuals at ultra-high risk (UHR) for psychosis. The study sample comprised 80 neuroleptic-naïve UHR individuals aged 13-25 years. Associations among erythrocyte membrane fatty acid levels, measured by gas chromatography, and cognitive functioning were investigated in UHR patients. Subjects were divided into terciles based on their scores on the cognitive factor of the Positive and Negative Syndrome Scale. The Zahlen-Verbindungs Test (ZVT) (the number-combination test) was also used as a measure of information-processing speed. Exploratory analysis was conducted to investigate the relationship between membrane fatty acid levels with the size of the intracranial area (ICA), a neurodevelopmental measure relevant to schizophrenia, in half of subjects (n=40) using magnetic resonance imaging. The adjusted analysis revealed that omega-9 eicosenoic and erucic acid levels were significantly higher, but omega-3 docosahexaenoic acid levels were significantly lower, in the cognitively impaired than in the cognitively intact group. We found a significant negative association of eicosenoic, erucic, and gamma-linoleic acids with ZVT scores. A negative association between ICA and membrane levels of eicosenoic acid was also found. This is the first study to demonstrate the relationship between membrane fatty acids and cognitive function in neuroleptic-naïve subjects at UHR for psychosis. The study findings indicate that abnormalities in membrane fatty acids may be associated with the neurodevelopmental disruption associated with the cognitive impairments of individuals at UHR for psychosis.

Impact of ketamine on learning and memory function, neuronal apoptosis and its potential association with miR-214 and PTEN in adolescent rats

Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, is used as a general pediatric anesthetic and anti-depressive drug. Recent studies suggest that ketamine enhances neuronal apoptosis in developing rats. The goal of this study is to explore whether ketamine could result in learning and memory impairment and neurodegeneration in adolescent rats, and if so, whether the effects of ketamine are associated with miR-214 and PTEN expression. Fifty-day-old SD rats were randomly divided into three groups receiving ketamine at 30, or 80 mg/kg, i.p. or saline for seven consecutive days. Twenty-four hours after the last treatment, learning and memory function were tested by the Morris water maze. The rats were then decapitated, and the brains were isolated for detection of neuronal apoptosis and protein PTEN expression by TUNEL and immunohistochemistry respectively. Expression levels of the miR-214 and PTEN in the hippocampus were measured by qRT-PCR and western blot analysis respectively. Ketamine administered to the adolescent rats at a dose of 80 mg/kg rather than the lower dose of 30 mg/kg caused learning and memory impairment, increased the number of apoptotic cells in the hippocampal CA1 region, cerebral cortex and subcortical region, decreased the miR-214 levels and increased PTEN protein expression in hippocampus. The results suggest that ketamine at a dose of 80 mg/kg in the adolescent rats is able to induce the learning and memory impairment and neurodegeneration, in which the down-regulation of miR-214 and high expression of PTEN protein may be involved.

Omega-3 fatty acids alter behavioral and oxidative stress parameters in animals subjected to fenproporex administration

Studies have consistently reported the participation of oxidative stress in bipolar disorder (BD). Evidences indicate that omega-3 (ω3) fatty acids play several important roles in brain development and functioning. Moreover, preclinical and clinical evidence suggests roles for ω3 fatty acids in BD. Considering these evidences, the present study aimed to investigate the effects of ω3 fatty acids on locomotor behavior and oxidative stress parameters (TBARS and protein carbonyl content) in brain of rats subjected to an animal model of mania induced by fenproporex. The fenproporex treatment increased locomotor behavior in saline-treated rats under reversion and prevention model, and ω3 fatty acids prevented fenproporex-related hyperactivity. Moreover, fenproporex increased protein carbonyls in the prefrontal cortex and cerebral cortex, and the administration of ω3 fatty acids reversed this effect. Lipid peroxidation products also are increased in prefrontal cortex, striatum, hippocampus and cerebral after fenproporex administration, but ω3 fatty acids reversed this damage only in the hippocampus. On the other hand, in the prevention model, fenproporex increased carbonyl content only in the cerebral cortex, and administration of ω3 fatty acids prevented this damage. Additionally, the administration of fenproporex resulted in a marked increased of TBARS in the prefrontal cortex, hippocampus, striatum and cerebral cortex, and prevent this damage in the prefrontal cortex, hippocampus and striatum. In conclusion, we are able to demonstrate that fenproporex-induced hyperlocomotion and damage through oxidative stress were prevented by ω3 fatty acids. Thus, the ω3 fatty acids may be important adjuvant therapy of bipolar disorder.

Evaluation of acetylcholinesterase activity and behavioural alterations induced by ketamine in an animal model of schizophrenia

OBJECTIVE

Cognitive deficits in schizophrenia play a crucial role in its clinical manifestation and seem to be related to changes in the cholinergic system, specifically the action of acetylcholinesterase (AChE). Considering this context, the aim of this study was to evaluate the chronic effects of ketamine in the activity of AChE, as well as in behavioural parameters involving learning and memory.

METHODS

The ketamine was administered for 7 days. A duration of 24 h after the last injection, the animals were submitted to behavioural tests. The activity of AChE in prefrontal cortex, hippocampus and striatum was measured at different times after the last injection (1, 3, 6 and 24 h).

RESULTS

The results indicate that ketamine did not affect locomotor activity and stereotypical movements. However, a cognitive deficit was observed in these animals by examining their behaviour in inhibitory avoidance. In addition, an increase in AChE activity was observed in all structures analysed 1, 3 and 6 h after the last injection. Differently, serum activity of AChE was similar between groups.

CONCLUSION

Chronic administration of ketamine in an animal model of schizophrenia generates increased AChE levels in different brain tissues of rats that lead to cognitive deficits. Therefore, further studies are needed to elucidate the complex mechanisms associated with schizophrenia.