Is prophylactic psychiatry around the corner? combating adolescent oxidative stress for adult psychosis and schizophrenia

Longitudinal changes in brain metabolites in healthy controls and patients with first episode psychosis: a 7-Tesla MRS study

Seven Tesla magnetic resonance spectroscopy (7T MRS) offers a precise measurement of metabolic levels in the human brain via a non-invasive approach. Studying longitudinal changes in brain metabolites could help evaluate the characteristics of disease over time. This approach may also shed light on how the age of study participants and duration of illness may influence these metabolites. This study used 7T MRS to investigate longitudinal patterns of brain metabolites in young adulthood in both healthy controls and patients. A four-year longitudinal cohort with 38 patients with first episode psychosis (onset within 2 years) and 48 healthy controls was used to examine 10 brain metabolites in 5 brain regions associated with the pathophysiology of psychosis in a comprehensive manner. Both patients and controls were found to have significant longitudinal reductions in glutamate in the anterior cingulate cortex (ACC). Only patients were found to have a significant decrease over time in γ-aminobutyric acid, N-acetyl aspartate, myo-inositol, total choline, and total creatine in the ACC. Together we highlight the ACC with dynamic changes in several metabolites in early-stage psychosis, in contrast to the other 4 brain regions that also are known to play roles in psychosis. Meanwhile, glutathione was uniquely found to have a near zero annual percentage change in both patients and controls in all 5 brain regions during a four-year follow-up in young adulthood. Given that a reduction of the glutathione in the ACC has been reported as a feature of treatment-refractory psychosis, this observation further supports the potential of glutathione as a biomarker for this subset of patients with psychosis.

Schizophrenia Synaptic Pathology and Antipsychotic Treatment in the Framework of Oxidative and Mitochondrial Dysfunction: Translational Highlights for the Clinics and Treatment

Schizophrenia is a worldwide mental illness characterized by alterations at dopaminergic and glutamatergic synapses resulting in global dysconnectivity within and between brain networks. Impairments in inflammatory processes, mitochondrial functions, energy expenditure, and oxidative stress have been extensively associated with schizophrenia pathophysiology. Antipsychotics, the mainstay of schizophrenia pharmacological treatment and all sharing the common feature of dopamine D2 receptor occupancy, may affect antioxidant pathways as well as mitochondrial protein levels and gene expression. Here, we systematically reviewed the available evidence on antioxidants' mechanisms in antipsychotic action and the impact of first- and second-generation compounds on mitochondrial functions and oxidative stress. We further focused on clinical trials addressing the efficacy and tolerability of antioxidants as an augmentation strategy of antipsychotic treatment. EMBASE, Scopus, and Medline/PubMed databases were interrogated. The selection process was conducted in respect of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Several mitochondrial proteins involved in cell viability, energy metabolism, and regulation of oxidative systems were reported to be significantly modified by antipsychotic treatment with differences between first- and second-generation drugs. Finally, antioxidants may affect cognitive and psychotic symptoms in patients with schizophrenia, and although the evidence is only preliminary, the results indicate that further studies are warranted.

Schizophrenia and risk of new-onset inflammatory bowel disease: a nationwide longitudinal study

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammatory disorder with increasing global prevalence. The risk of IBD in patients with schizophrenia remains unclear. We aim to investigate the risk of new-onset IBD in patients with schizophrenia compared with matched controls.

METHODS

We conducted a retrospective, population-based cohort study utilising patient data from the Taiwan National Health Insurance Research Database collected between January 1, 2001, and December 31, 2011. Patients diagnosed with schizophrenia by board-certified psychiatrists without prior diagnosis of IBD were enrolled and matched to controls in 1:4 fashion by age, sex, residence, income level and medical comorbidities. Adjusted hazard ratios (HRs) for new-onset IBD and sub-analyses were determined using Cox regression analysis with adjustments.

RESULTS

Among 116 164 patients with schizophrenia and 464 656 matched controls, overall incidence of IBD among patients was significantly higher (1.14% vs. 0.25%). Average age of IBD diagnosis was 46.82 among patients with schizophrenia, versus 55.30 among controls. The HR of developing IBD among patients was 3.28, with a 95% confidence interval (95% CI) 2.49-4.33. IBD risk was higher among patients with psychiatric admissions more than once per year (HR 7.99, 95% CI 5.25-12.15) compared to those hospitalised less frequently (HR 2.72, 95% CI 2.03-3.66).

CONCLUSIONS

This population-based cohort study demonstrates a significant association between schizophrenia and subsequent IBD development. Patients with schizophrenia develop IBD at a younger age, and the risk increases with inadequately controlled schizophrenia. Physician vigilance and awareness of this correlation will improve IBD diagnosis and management among this vulnerable patient population.

Thalamic reticular nucleus impairments and abnormal prefrontal control of dopamine system in a developmental model of schizophrenia: prevention by N-acetylcysteine

Recent evidence showed thalamic abnormalities in schizophrenia involving disruptions to the parvalbumin neurons in the thalamic reticular nucleus (TRN). However, their functional consequences, as well as a potential linkage to oxidative stress, are unclear. The TRN is posited to gate prefrontal control of dopamine neuron activity in the ventral tegmental area (VTA). Thus, we hypothesized that schizophrenia-related TRN abnormalities might contribute to dopamine dysregulation, a well-known feature of the disorder. To test this, in adult rats exposed prenatally to methylazoxymethanol acetate (MAM rats), oxidative impairments to the parvalbumin neurons in the anterior TRN were assessed by immunohistochemistry. Using in vivo electrophysiology, we investigated whether inactivation of the prefrontal cortex would produce differential effects on VTA dopamine neurons in MAM rats. We show that MAM rats displayed reduced markers of parvalbumin and wisteria floribunda agglutinin-labeled perineuronal nets, correlating with increased markers of oxidative stress (8-oxo-7, 8-dihydro-20-deoxyguanosine, and 3-nitrotyrosine). Moreover, MAM rats displayed heightened baseline and abnormal prefrontal control of VTA dopamine neuron activity, as tetrodotoxin-induced inactivation of the infralimbic prefrontal cortex decreased the dopamine population activity, contrary to the normal increase in controls. Such dopamine neuron dysregulation was recapitulated by enzymatic perineuronal net digestion in the TRN of normal rats. Furthermore, juvenile (postnatal day 11-25) antioxidant treatment (N-acetyl-cysteine, 900 mg/L drinking water) prevented all these impairments in MAM rats. Our findings suggest that early accumulation of oxidative stress in the TRN may shape the later onset of schizophrenia pathophysiology, highlighting redox regulation as a potential target for early intervention.

Effect of Neonatal Treatment With the NMDA Receptor Antagonist, MK-801, During Different Temporal Windows of Postnatal Period in Adult Prefrontal Cortical and Hippocampal Function

The neonatal MK-801 model of schizophrenia has been developed based on the neurodevelopmental and NMDA receptor hypofunction hypotheses of schizophrenia. This animal model is generated with the use of the NMDA receptor antagonist, MK-801, during different temporal windows of postnatal life of rodents leading to behavioral defects in adulthood. However, no studies have examined the role of specific postnatal time periods in the neonatal MK-801 (nMK-801) rodent model and the resulting behavioral and neurobiological effects. Thus, the goal of this study is to systematically investigate the role of NMDA hypofunction, during specific temporal windows in postnatal life on different cognitive and social behavioral paradigms, as well as various neurobiological effects during adulthood. Both female and male mice were injected intraperitoneally (i.p.) with MK-801 during postnatal days 7-14 (p7-14) or 11-15 (p11-15). Control mice were injected with saline during the respective time period. In adulthood, mice were tested in various cognitive and social behavioral tasks. Mice nMK-801-treated on p7-14 show impaired performance in the novel object, object-to-place, and temporal order object recognition (TOR) tasks, the sociability test, and contextual fear extinction. Mice nMK-801-treated on p11-15 only affects performance in the TOR task, the social memory test, and contextual fear extinction. No differences were identified in the expression of NMDA receptor subunits, the synapsin or PSD-95 proteins, either in the prefrontal cortex (PFC) or the hippocampus (HPC), brain regions significantly affected in schizophrenia. The number of parvalbumin (PV)-expressing cells is significantly reduced in the PFC, but not in the HPC, of nMK-801-treated mice on p7-14 compared to their controls. No differences in PV-expressing cells (PFC or HPC) were identified in nMK-801-treated mice on p11-15. We further examined PFC function by recording spontaneous activity in a solution that allows up state generation. We find that the frequency of up states is significantly reduced in both nMK-801-treated mice on p7-14 and p11-15 compared to saline-treated mice. Furthermore, we find adaptations in the gamma and high gamma activity in nMK-801-treated mice. In conclusion, our results show that MK-801 treatment during specific postnatal temporal windows has differential effects on cognitive and social behaviors, as well as on underlying neurobiological substrates.

Timely N-Acetyl-Cysteine and Environmental Enrichment Rescue Oxidative Stress-Induced Parvalbumin Interneuron Impairments via MMP9/RAGE Pathway: A Translational Approach for Early Intervention in Psychosis

Research in schizophrenia (SZ) emphasizes the need for new therapeutic approaches based on antioxidant/anti-inflammatory compounds and psycho-social therapy. A hallmark of SZ is a dysfunction of parvalbumin-expressing fast-spiking interneurons (PVI), which are essential for neuronal synchrony during sensory/cognitive processing. Oxidative stress and inflammation during early brain development, as observed in SZ, affect PVI maturation. We compared the efficacy of N-acetyl-cysteine (NAC) and/or environmental enrichment (EE) provided during juvenile and/or adolescent periods in rescuing PVI impairments induced by an additional oxidative insult during childhood in a transgenic mouse model with gluthation deficit (Gclm KO), relevant for SZ. We tested whether this rescue was promoted by the inhibition of MMP9/RAGE mechanism, both in the mouse model and in early psychosis (EP) patients, enrolled in a double-blind, randomized, placebo-controlled clinical trial of NAC supplementation for 6 months. We show that a sequential combination of NAC+EE applied after an early-life oxidative insult recovers integrity and function of PVI network in adult Gclm KO, via the inhibition of MMP9/RAGE. Six-month NAC treatment in EP patients reduces plasma sRAGE in association with increased prefrontal GABA, improvement of cognition and clinical symptoms, suggesting similar neuroprotective mechanisms. The sequential combination of NAC+EE reverses long-lasting effects of an early oxidative insult on PVI/perineuronal net (PNN) through the inhibition of MMP9/RAGE mechanism. In analogy, patients vulnerable to early-life insults could benefit from a combined pharmacological and psycho-social therapy.

Glutamate and microglia activation as a driver of dendritic apoptosis: a core pathophysiological mechanism to understand schizophrenia

Schizophrenia disorder remains an unsolved puzzle. However, the integration of recent findings from genetics, molecular biology, neuroimaging, animal models and translational clinical research offers evidence that the synaptic overpruning hypothesis of schizophrenia needs to be reassessed. During a critical period of neurodevelopment and owing to an imbalance of excitatory glutamatergic pyramidal neurons and inhibitory GABAergic interneurons, a regionally-located glutamate storm might occur, triggering excessive dendritic pruning with the activation of local dendritic apoptosis machinery. The apoptotic loss of dendritic spines would be aggravated by microglia activation through a recently described signaling system from complement abnormalities and proteins of the MHC, thus implicating the immune system in schizophrenia. Overpruning of dendritic spines coupled with aberrant synaptic plasticity, an essential function for learning and memory, would lead to brain misconnections and synaptic inefficiency underlying the primary negative symptoms and cognitive deficits of schizophrenia. This driving hypothesis has relevant therapeutic implications, including the importance of pharmacological interventions during the prodromal phase or the transition to psychosis, targeting apoptosis, microglia cells or the glutamate storm. Future research on apoptosis and brain integrity should combine brain imaging, CSF biomarkers, animal models and cell biology.

Betaine ameliorates schizophrenic traits by functionally compensating for KIF3-based CRMP2 transport

In schizophrenia (SCZ), neurons in the brain tend to undergo gross morphological changes, but the related molecular mechanism remains largely elusive. Using Kif3b^+/- mice as a model with SCZ-like behaviors, we found that a high-betaine diet can significantly alleviate schizophrenic traits related to neuronal morphogenesis and behaviors. According to a deficiency in the transport of collapsin response mediator protein 2 (CRMP2) by the KIF3 motor, we identified a significant reduction in lamellipodial dynamics in developing Kif3b^+/- neurons as a cause of neurite hyperbranching. Betaine administration significantly decreases CRMP2 carbonylation, which enhances the F-actin bundling needed for proper lamellipodial dynamics and microtubule exclusion and may thus functionally compensate for KIF3 deficiency. Because the KIF3 expression levels tend to be downregulated in the human prefrontal cortex of the postmortem brains of SCZ patients, this mechanism may partly participate in human SCZ pathogenesis, which we hypothesize could be alleviated by betaine administration.

The epigenetic modulation of alcohol/ethanol and cannabis exposure/co-exposure during different stages

Studies have reported the significant economic impact of smoking cannabis and drinking alcohol In the USA. It was estimated that the costs of cannabis-related treatment, hospitalization and loss of work-related pay have amounted to $200 billion. (Andersen AM, Dogan MV, Beach SRH, Philibert RA. 2015 Genes 6, 991-1022. ( doi:10.3390/genes6040991 )). Data from the National Epidemiologic Survey on Alcohol and Related Conditions showed that individuals with general anxiety disorder and substance use disorder (GAD-SUD) have higher psychiatric comorbidity rates than those without substance use disorder (Alegría AA, Hasin DS, Nunes EV, Liu SM, Davies C, Grant BF, Blanco C. 2010 J. Clin. Psychiatry 71, 1187-1195. ( doi:10.4088/JCP.09m05328gry )). Moreover, the criminal justice system is significantly impacted by this cost (Andersen AM, Dogan MV, Beach SRH, Philibert RA. 2015 Genes 6, 991-1022. ( doi:10.3390/genes6040991 )). Despite the increasing use of cannabis, there are still too many obscure facts. One of the new areas that scientific evidence shows is impacted negatively by cannabis use is the epigenome, which is an understudied area that we are still learning about. In addition, over the past few decades, we have seen various social and healthcare changes that have raised critical questions about their ongoing roles in regulating marijuana and alcohol use. This is important because of the increasing popularity and usage across various ages especially young adults and teenagers. More than 97.5 million Americans over 12 years old have used cannabis for non-medical use despite the significant side effects, with 1 in 10 users developing cannabis dependence (Crean RD, Crane NA, Mason BJ. 2011 J. Addict. Med. 5, 1-8. ( doi:10.1097/ADM.0b013e31820c23fa ), Office of Applied Studies. 2006 Substance Abuse and Mental Health Services Administration, USA.). It was reported that 16% of substance abuse admissions in the USA were for cannabis-related symptoms, which is second only to alcohol-related disorders (Agalioti T, Lomvardas S, Parekh B, Yie J, Maniatis T, Thanos D. 2000 Cell 103, 667-678. ( doi:10.1016/S0092-8674(00)00169-0 ), Soutoglou E, Talianidis I. 2002 Science 295, 1901-1904. ( doi:10.1126/science.1068356 )). Today there are thirty-one states and the District of Columbia that currently have legalized marijuana for either medical or recreational use. Data about marijuana use from NIAAA's National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) indicates that 'in total, 79 000 people were interviewed on alcohol and drug use. When examined by age young adults (ages 18-21) were found to be at highest risk for marijuana use and marijuana use disorder, with use increasing from 10.5 to 21.2% and disorder increasing from 4.4 to 7.5%'. 'Given these facts, George Koob, PhD, director of NIAAA stated the importance for the scientific community to convey this information to the public about the potential hazards of marijuana and it's use'. On the other hand, according to the National Institute on Alcohol Abuse and Alcoholism, 16 million adults suffer from alcohol use disorders. To the best of our knowledge, epigenetic mechanisms have been previously studied in alcohol and cannabis abuse separately. Recent studies highlighted the molecular mechanisms that are linked with drug-induced transcriptional regulation, behavioural abnormalities and neurodegeneration, which has emphasized the role of chromatin modification/remodelling in the generation of drug activation of certain genes and the disabling of others, and the effect of that on addiction (Maze I, Nestler EJ. 2011 Ann. N. Y. Acad. Sci. 1216, 99-113. ( doi:10.1111/j.1749-6632.2010.05893.x ); Renthal W, Nestler EJ. 2008 Trends Mol. Med. 14, 341-350. ( doi:10.1016/j.molmed.2008.06.004 )). In this review, we will give an overview of epigenome science relevant to cannabis/the endocannabinoid system and the potential of epigenetic overlap between alcohol and cannabinergic activity at different stages, to aid further investigations that could bring more treatment options to our horizon.

Oxidation-reduction mechanisms in psychiatric disorders: A novel target for pharmacological intervention

While neurotransmitter dysfunction represents a key component in mental illnesses, there is now a wide agreement for a central pathophysiological hub that includes hormones, neuroinflammation, redox mechanisms as well as oxidative stress. With respect to oxidation-reduction (redox) mechanisms, preclinical and clinical evidence suggests that an imbalance in the pro/anti-oxidative homeostasis toward the increased production of substances with oxidizing potential may contribute to the etiology and manifestation of different psychiatric disorders. The substantial and continous demand for energy renders the brain highly susceptible to disturbances in its energy supply, especially following exposure to stressful events, which may lead to overproduction of reactive oxygen and nitrogen species under conditions of perturbed antioxidant defenses. This will eventually induce different molecular alterations, including extensive protein and lipid peroxidation, increased blood-brain barrier permeability and neuroinflammation, which may contribute to the changes in brain function and morphology observed in mental illnesses. This view may also reconcile different key concepts for psychiatric disorders, such as the neurodevelopmental origin of these diseases, as well as the vulnerability of selective cellular populations that are critical for specific functional abnormalities. The possibility to pharmacologically modulate the redox system is receiving increasing interest as a novel therapeutic strategy to counteract the detrimental effects of the unbalance in brain oxidative mechanisms. This review will describe the main mechanisms and mediators of the redox system and will examine the alterations of oxidative stress found in animal models of psychiatric disorders as well as in patients suffering from mental illnesses, such as schizophrenia and major depressive disorder. In addition, it will discuss studies that examined the effects of psychotropic drugs, including antipsychotics and antidepressants, on the oxidative balance as well as studies that investigated the effectiveness of a direct modulation of oxidative mechanisms in counteracting the behavioral and functional alterations associated with psychiatric disorders, which supports the promising role of the redox system as a novel therapeutic target for the improved treatment of brain disorders.

Galantamine-Memantine Combination as an Antioxidant Treatment for Schizophrenia

PURPOSE OF REVIEW

The objective of this article is to highlight the potential role of the galantamine-memantine combination as a novel antioxidant treatment for schizophrenia.

RECENT FINDINGS

In addition to the well-known mechanisms of action of galantamine and memantine, these medications also have antioxidant activity. Furthermore, an interplay exists between oxidative stress, inflammation (redox-inflammatory hypothesis), and kynurenine pathway metabolites. Also, there is an interaction between brain-derived neurotrophic factor and oxidative stress in schizophrenia. Oxidative stress may be associated with positive, cognitive, and negative symptoms and impairments in white matter integrity in schizophrenia. The antipsychotic-galantamine-memantine combination may provide a novel strategy in schizophrenia to treat positive, cognitive, and negative symptoms.

SUMMARY

A "single antioxidant" may be inadequate to counteract the complex cascade of oxidative stress. The galantamine-memantine combination as "double antioxidants" is promising. Hence, randomized controlled trials are warranted with the antipsychotic-galantamine-memantine combination with oxidative stress and antioxidant biomarkers in schizophrenia.

Dietary glucoraphanin prevents the onset of psychosis in the adult offspring after maternal immune activation

Maternal immune activation (MIA) contributes to behavioral abnormalities relevant to schizophrenia in adult offspring, although the molecular mechanisms underlying MIA-induced behavioral changes remain unclear. Here we demonstrated that dietary intake of glucoraphanin (GF), the precursor of a natural antioxidant sulforaphane, during juvenile and adolescent stages prevented cognitive deficits and loss of parvalbumin (PV) immunoreactivity in the medial prefrontal cortex (mPFC) of adult offspring after MIA. Gene set enrichment analysis by RNA sequencing showed that MIA caused abnormal expression of centrosome-related genes in the PFC and hippocampus of adult offspring, and that dietary intake of GF improved these abnormal gene expressions. Particularly, MIA increased the expression of suppressor of fermentation-induced loss of stress resistance protein 1 (Sfi1) mRNA in the PFC and hippocampus of adult offspring, and dietary intake of GF prevented the expression of Sfi1 mRNA in these regions. Interestingly, we found altered expression of SFI1 in the postmortem brains and SFI1 mRNA in hair follicle cells from patients with schizophrenia compared with controls. Overall, these data suggest that centrosome-related genes may play a role in the onset of psychosis in offspring after MIA. Therefore, dietary intake of GF-rich vegetables in high-risk psychosis subjects may prevent the transition to psychosis in young adulthood.

N-acetylcysteine in a Double-Blind Randomized Placebo-Controlled Trial: Toward Biomarker-Guided Treatment in Early Psychosis

Biomarker-guided treatments are needed in psychiatry, and previous data suggest oxidative stress may be a target in schizophrenia. A previous add-on trial with the antioxidant N-acetylcysteine (NAC) led to negative symptom reductions in chronic patients. We aim to study NAC's impact on symptoms and neurocognition in early psychosis (EP) and to explore whether glutathione (GSH)/redox markers could represent valid biomarkers to guide treatment. In a double-blind, randomized, placebo-controlled trial in 63 EP patients, we assessed the effect of NAC supplementation (2700 mg/day, 6 months) on PANSS, neurocognition, and redox markers (brain GSH [GSHmPFC], blood cells GSH levels [GSHBC], GSH peroxidase activity [GPxBC]). No changes in negative or positive symptoms or functional outcome were observed with NAC, but significant improvements were found in favor of NAC on neurocognition (processing speed). NAC also led to increases of GSHmPFC by 23% (P = .005) and GSHBC by 19% (P = .05). In patients with high-baseline GPxBC compared to low-baseline GPxBC, subgroup explorations revealed a link between changes of positive symptoms and changes of redox status with NAC. In conclusion, NAC supplementation in a limited sample of EP patients did not improve negative symptoms, which were at modest baseline levels. However, NAC led to some neurocognitive improvements and an increase in brain GSH levels, indicating good target engagement. Blood GPx activity, a redox peripheral index associated with brain GSH levels, could help identify a subgroup of patients who improve their positive symptoms with NAC. Thus, future trials with antioxidants in EP should consider biomarker-guided treatment.

Glutathione, the Major Redox Regulator, in the Prefrontal Cortex of Individuals at Clinical High Risk for Psychosis

INTRODUCTION

Oxidative stress and glutathione dysregulation have been implicated in the etiology of schizophrenia. To date, most in vivo studies have investigated alterations in cerebral glutathione levels in patients in which the disorder is already established; however, whether oxidative stress actually predates the onset of psychosis remains unknown. In the current study, we investigated cerebral glutathione levels of antipsychotic-naïve individuals at clinical high risk for psychosis. As exploratory analyses, we also investigated the associations between cerebral glutathione levels and peripheral glutathione peroxidase activity and clinical and neuropsychological measures.

METHODS

Glutathione levels were measured in the medial prefrontal cortex of 30 clinical high risk (n=26 antipsychotic naïve) and 26 healthy volunteers using 3T proton magnetic resonance spectroscopy. Each participant was assessed for glutathione peroxidase activity in plasma and genotyped for the glutamate cysteine ligase catalytic subunit polymorphism.

RESULTS

No significant differences were observed in glutathione levels between clinical high risk and healthy volunteers in the medial prefrontal cortex (F(1,54)=0.001, P =0.98). There were no significant correlations between cerebral glutathione levels and clinical and neuropsychological measures. Similarly, no significant differences were found in peripheral glutathione peroxidase activity between clinical high risk and healthy volunteers (F(1,37)=0.15, P =0.70). However, in clinical high risk, we observed a significant effect of lifetime history of cannabis use on glutathione peroxidase activity (F(1,23)=7.41, P =0.01).

DISCUSSION

The lack of significant differences between antipsychotic naïve clinical high risk and healthy volunteers suggests that alterations in glutathione levels in medial prefrontal cortex are not present in the clinical high risk state.

Schizophrenia

Schizophrenia is a complex, heterogeneous behavioural and cognitive syndrome that seems to originate from disruption of brain development caused by genetic or environmental factors, or both. Dysfunction of dopaminergic neurotransmission contributes to the genesis of psychotic symptoms, but evidence also points to a widespread and variable involvement of other brain areas and circuits. Disturbances of synaptic function might underlie abnormalities of neuronal connectivity that possibly involves interneurons, but the precise nature, location, and timing of these events are uncertain. At present, treatment mainly consists of antipsychotic drugs combined with psychological therapies, social support, and rehabilitation, but a pressing need for more effective treatments and delivery of services exists. Advances in genomics, epidemiology, and neuroscience have led to great progress in understanding the disorder, and the opportunities for further scientific breakthrough are numerous--but so are the challenges.

Pharmacological targeting of redox regulation systems as new therapeutic approach for psychiatric disorders: A literature overview

Redox dysregulation occurs following a disequilibrium between reactive oxygen species (ROS) producing and degrading systems, i.e. mitochondria, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and nitric oxide synthase (NOS) on one hand and the principal antioxidant system, the glutathione, on the other hand. Increasing recent evidence points towards a pathogenetic role of an altered redox state in the development of several mental disorders, such as anxiety, bipolar disorders, depression, psychosis, autism and post-traumaticstress disorders (PTSD). In this regard, pharmacological targeting of the redox state regulating systems in the brain has been proposed as an innovative and promising therapeutic approach for the treatment of these mental diseases. This review will summarize current knowledge obtained from both pre-clinical and clinical studies in order to descant "lights and shadows" of targeting pharmacologically both the producing and degrading reactive oxygen species (ROS) systems in psychiatric disorders.

Converging models of schizophrenia--Network alterations of prefrontal cortex underlying cognitive impairments

The prefrontal cortex (PFC) and its connections with other brain areas are crucial for cognitive function. Cognitive impairments are one of the core symptoms associated with schizophrenia, and manifest even before the onset of the disorder. Altered neural networks involving PFC contribute to cognitive impairments in schizophrenia. Both genetic and environmental risk factors affect the development of the local circuitry within PFC as well as development of broader brain networks, and make the system vulnerable to further insults during adolescence, leading to the onset of the disorder in young adulthood. Since spared cognitive functions correlate with functional outcome and prognosis, a better understanding of the mechanisms underlying cognitive impairments will have important implications for novel therapeutics for schizophrenia focusing on cognitive functions. Multidisciplinary approaches, from basic neuroscience to clinical studies, are required to link molecules, circuitry, networks, and behavioral phenotypes. Close interactions among such fields by sharing a common language on connectomes, behavioral readouts, and other concepts are crucial for this goal.

Involvement of oxidative stress and mitochondrial/lysosomal cross-talk in olanzapine cytotoxicity in freshly isolated rat hepatocytes

1. Olanzapine (OLZ) is a widely used atypical antipsychotic agent for the treatment of schizophrenia and other disorders. Serious hepatotoxicity and elevated liver enzymes have been reported in patients receiving OLZ. However, the cellular and molecular mechanisms of the OLZ hepatotoxicity are unknown. 2. In this study, the cytotoxic effect of OLZ on freshly isolated rat hepatocytes was assessed. Our results showed that the cytotoxicity of OLZ in hepatocytes is mediated by overproduction of reactive oxygen species (ROS), mitochondrial potential collapse, lysosomal membrane leakiness, GSH depletion and lipid peroxidation preceding cell lysis. All the aforementioned OLZ-induced cellular events were significantly (p < 0.05) prevented by ROS scavengers, antioxidants, endocytosis inhibitors and adenosine triphosphate generators. Also, the present results demonstrated that CYP450 is involved in OLZ-induced oxidative stress and cytotoxicity mechanism. 3. It is concluded that OLZ hepatotoxicity is associated with both mitochondrial/lysosomal involvement following the initiation of oxidative stress in hepatocytes.

New Targets for Prevention of Schizophrenia: Is It Time for Interventions in the Premorbid Phase?

A number of influences have converged that make this Special Theme Issue timely: "A New Direction: Considering Developmentally Sensitive Targets for Very Early Intervention in Schizophrenia". These factors include: 1. the substantial knowledge about premorbid developmental vulnerabilities to psychosis, especially regarding schizophrenia; 2. the promising results emerging from interventions during the clinical high-risk (CHR) phase of psychosis and; 3. the recognition that the CHR period is a relatively late phase of developmental derailment. These factors have together led to a perspective that even earlier intervention is warranted. This paper briefly summarizes the articles comprising the Special Theme including new data on early neurocognitive development, proposed potential targets for psychosocial and psychopharmacological interventions during the premorbid period as early as pregnancy, and ethical challenges. These thought experiments must be empirically tested, and the ethical challenges overcome as posed by the various interventions, which range from relatively low risk, supportive, psychosocial to higher risk, experimental, pharmacological interventions. All of the interventions proposed require careful study of ethics, safety, potential stigma, feasibility, efficacy and tolerability, and the meaning to the people involved.

Targeting Oxidative Stress and Aberrant Critical Period Plasticity in the Developmental Trajectory to Schizophrenia

Schizophrenia is a neurodevelopmental disorder reflecting a convergence of genetic risk and early life stress. The slow progression to first psychotic episode represents both a window of vulnerability as well as opportunity for therapeutic intervention. Here, we consider recent neurobiological insight into the cellular and molecular components of developmental critical periods and their vulnerability to redox dysregulation. In particular, the consistent loss of parvalbumin-positive interneuron (PVI) function and their surrounding perineuronal nets (PNNs) as well as myelination in patient brains is consistent with a delayed or extended period of circuit instability. This linkage to critical period triggers (PVI) and brakes (PNN, myelin) implicates mistimed trajectories of brain development in mental illness. Strategically introduced antioxidant treatment or later reinforcement of molecular brakes may then offer a novel prophylactic psychiatry.

Dietary Intake of Sulforaphane-Rich Broccoli Sprout Extracts during Juvenile and Adolescence Can Prevent Phencyclidine-Induced Cognitive Deficits at Adulthood

Oxidative stress and inflammation play a role in cognitive impairment, which is a core symptom of schizophrenia. Furthermore, a hallmark of the pathophysiology of this disease is the dysfunction of cortical inhibitory γ-aminobutyric acid (GABA) neurons expressing parvalbumin (PV), which is also involved in cognitive impairment. Sulforaphane (SFN), an isothiocyanate derived from broccoli, is a potent activator of the transcription factor Nrf2, which plays a central role in the inducible expressions of many cytoprotective genes in response to oxidative stress. Keap1 is a cytoplasmic protein that is essential for the regulation of Nrf2 activity. Here, we found that pretreatment with SFN attenuated cognitive deficits, the increase in 8-oxo-dG-positive cells, and the decrease in PV-positive cells in the medial prefrontal cortex and hippocampus after repeated administration of phencyclidine (PCP). Furthermore, PCP-induced cognitive deficits were improved by the subsequent subchronic administration of SFN. Interestingly, the dietary intake of glucoraphanin (a glucosinolate precursor of SFN) during the juvenile and adolescence prevented the onset of PCP-induced cognitive deficits as well as the increase in 8-oxo-dG-positive cells and the decrease in PV-positive cells in the brain at adulthood. Moreover, the NRF2 gene and the KEAP1 gene had an epistatic effect on cognitive impairment (e.g., working memory and processing speed) in patients with schizophrenia. These findings suggest that SFN may have prophylactic and therapeutic effects on cognitive impairment in schizophrenia. Therefore, the dietary intake of SFN-rich broccoli sprouts during the juvenile and adolescence may prevent the onset of psychosis at adulthood.

Sequence of Molecular Events during the Maturation of the Developing Mouse Prefrontal Cortex

Recent progress in psychiatric research has accumulated many mouse models relevant to developmental neuropsychiatric disorders using numerous genetic and environmental manipulations. Since the prefrontal cortex (PFC) is essential for cognitive functions whose impairments are central symptoms associated with the disorders in humans, it has become crucial to clarify altered developmental processes of PFC circuits in these mice. To that end, we aimed to understand a sequence of molecular events during normal mouse PFC development. Expression profiles for representative genes covering diverse biological processes showed that while there were little changes in genes for neuroreceptors and synaptic molecules during postnatal period, there were dramatic increases in expression of myelin-related genes and parvalbumin gene, peaking at postnatal day (P) 21 and P35, respectively. The timing of the peaks is different from one observed in the striatum. Furthermore, evaluation of the circuitry maturation by measuring extracellular glutamate in PFC revealed that sensitivity to an NMDA antagonist became adult-like pattern at P56, suggesting that some of maturation processes continue till P56. The trajectory of molecular events in the PFC maturation described here should help us to characterize how the processes are affected in model mice, an important first step for translational research.

Present and future of developmental neuropsychopharmacology

The field of child and adolescent psychiatry has always lagged behind adult psychiatry. With recent evidence that the vast majority of mental disorders, even when they emerge in adulthood, cause abnormal neurodevelopment and resultant emphasis on prevention and early intervention, there is a need to put child psychiatry at the top of the agenda in mental health research. This should also be the case for developmental neuropsychopharmacology. The target of drug discovery should shift toward a population younger than the one that is typically included in clinical trials. This is not only a matter of trying to replicate what has been found in individuals with mature brains; it is about searching for new strategies that address developing brains while the therapeutic window for their effect is still open. At present, major concerns in developmental psychopharmacology are over-prescription rates and use of psychotropic medications for conditions with a particularly underdeveloped evidence base, as well as adverse effects, especially potentially life-shortening cardiometabolic effects and suicidal ideation. The future of research in this area should focus on the use of drugs for primary and secondary prevention that would modify abnormal brain development.