Paliperidone Reversion of Maternal Immune Activation-Induced Changes on Brain Serotonin and Kynurenine Pathways

Emerging evidence indicates that early-life exposure to environmental factors may increase the risk for schizophrenia via inflammatory mechanisms. Inflammation can alter the metabolism of tryptophan through the oxidative kynurenine pathway to compounds with neurotoxic and neuroprotective activity and compromise serotonin (5-HT) synthesis. Here we investigate the role of serotonergic and kynurenine pathways in the maternal immune activation (MIA) animal model of schizophrenia. The potential reversion exerted by long-term antipsychotic treatment was also evaluated. MIA was induced by prenatal administration of polyinosinic:polycytidylic acid (poly (I:C)) in mice. Expression of different proteins and the content of different metabolites involved in the function of serotonergic and kynurenine pathways was assessed by RT-PCR, immunoblot and ELISA analyses in frontal cortex of the offspring after puberty. MIA decreased tissue 5-HT content and promoted changes in the expression of serotonin transporter, 5-HT2A and 5-HT2C receptors. Expression of indoleamine 2,3-dioxygenase 2 (IDO2) and kynurenine 3-monooxygenase (KMO) was increased by poly (I:C) whereas kynurenine aminotransferase II and its metabolite kynurenic acid were not altered. Long-term paliperidone was able to counteract MIA-induced changes in 5-HT and KMO, and to increase tryptophan availability and tryptophan hydroxylase-2 expression in poly (I:C) mice but not in controls. MIA-induced increase of the cytotoxic risk ratio of kynurenine metabolites (quinolinic/kynurenic acid) was also reversed by paliperidone. MIA induces specific long-term brain effects on serotonergic activity. Such effects seem to be related with alternative activation of the kynurenine metabolic pathway towards a cytotoxic status. Atypical antipsychotic paliperodine partially remediates abnormalities observed after MIA.This work was supported by MINECO-FEDER Funds (SAF201675500-R to JL; SAF2017-88126-R to JM); Centro de Investigacion en Red de Salud Mental, CIBERSAM; and the Basque Government (IT1211-19). Editoria

Kynurenine pathway in post-mortem prefrontal cortex and cerebellum in schizophrenia : relationship with monoamines and symptomatology

The cortico-cerebellar-thalamic-cortical circuit has been implicated in the emergence of psychotic symptoms in schizophrenia (SZ). The kynurenine pathway (KP) has been linked to alterations in glutamatergic and monoaminergic neurotransmission and to SZ symptomatology through the production of the metabolites quinolinic acid (QA) and kynurenic acid (KYNA). This work describes alterations in KP in the post-mortem prefrontal cortex (PFC) and cerebellum (CB) of 15 chronic SZ patients and 14 control subjects in PFC and 13 control subjects in CB using immunoblot for protein levels and ELISA for interleukins and QA and KYNA determinations. Monoamine metabolites were analysed by high-performance liquid chromatography and SZ symptomatology was assessed by Positive and Negative Syndrome Scale (PANSS). The association of KP with inflammatory mediators, monoamine metabolism and SZ symptomatology was explored. In the PFC, the presence of the anti-inflammatory cytokine IL-10 together with IDO2 and KATII enzymes decreased in SZ, while TDO and KMO enzyme expression increased. A network interaction analysis showed that in the PFC IL-10 was coupled to the QA branch of the kynurenine pathway (TDO-KMO-QA), whereas IL-10 associated with KMO in CB. KYNA in the CB inversely correlated with negative and general PANSS psychopathology. Although there were no changes in monoamine metabolite content in the PFC in SZ, a network interaction analysis showed associations between dopamine and methoxyhydroxyphenylglycol degradation metabolite. Direct correlations were found between general PANSS psychopathology and the serotonin degradation metabolite, 5-hydroxyindoleacetic acid. Interestingly, KYNA in the CB inversely correlated with 5-hydroxyindoleacetic acid in the PFC. Thus, this work found alterations in KP in two brain areas belonging to the cortico-cerebellar-thalamic-cortical circuit associated with SZ symptomatology, with a possible impact across areas in 5-HT degradation. The online version contains supplementary material available at 10.1186/s12974-021-02260-6

Association Between Medication Adherence and Oxidative Stress in Patients With First-Episode Mania

Poor adherence is a major problem in patients with manic episodes that impairs functionality and has unknown effects on oxidative stress. The objective of this study was to analyze the relationship between adherence to medication, severity of symptoms and oxidative stress in a sample of patients with a first episode of mania. A longitudinal, 6-month study was performed in 60 patients, who were classified as adherent and non-adherent to medication (mainly antipsychotics). Blood levels of oxidative stress parameters and expression of the antioxidant nuclear transcription factor NRF2 in mononuclear cells of peripheral blood were assessed at baseline and at the end of follow-up. In addition, clinical symptoms and functioning were evaluated. Linear multivariate regression was used to determine the relationship between adherence, oxidative stress, and clinical symptoms. Finally, 44 patients completed follow-up. The results of this study showed that at 6-month follow-up, adherence was significantly associated with better functioning and reduced clinical symptoms. Additionally, more severe symptoms were associated with increased levels of oxidative stress and antioxidant parameters. At study completion, non-adherents exhibited greater levels of antioxidants than adherent patients. In conclusion, poor adherence to medication is associated with a poorer prognosis in the medium term and causes increased antioxidant response.This study has been funded by Instituto de Salud Carlos III through the projects PI12/02077, PI16/01164, PI14/01900 (Co-funded by European Regional Development Fund/European Social Fund. Investing in your future); the Basque Foundation for Health Innovation and Research (BIOEF); Networking Center for Biomedical Research in Mental Health (CIBERSAM) and the University of the Basque Country (GIC12/84). The psychiatric research department in University Hospital Araba is supported by the Stanley Research Foundation (03-RC-003). SG has a PhD fellowship from the University of the Basque Country

Cardiovascular risk in early psychosis. Relationship with inflammation and clinical features 6 months after diagnosis

Background: We aimed to investigate the state of cardiovascular risk/protection factors in early psychosis patients. Methods: A total 119 subjects were recruited during the first year after their first episode of psychosis. Eighty-five of these subjects were followed during the next 6 months. Cardiovascular risk/protection factors were measured in plasma and co-variated by sociodemographic/clinical characteristics. Multiple linear regression models detected the change of each biological marker from baseline to follow-up in relation to clinical scales, antipsychotic medication, and pro-/antiinflammatory mediators. Results: Glycosylated hemoglobin is a state biomarker in first episode of psychosis follow-up patients and inversely correlated to the Global Assessment of Functioning scale. We found opposite alterations in the levels of VCAM-1 and E-selectin in first episode of psychosis baseline conditions compared with control that were absent in the first episode of psychosis follow-up group. Adiponectin levels decreased in a continuum in both pathological time points studied. E-Selectin plasma levels were inversely related to total antipsychotic equivalents and adiponectin levels inversely co-related to the Global Assessment of Functioning scale. Finally, adiponectin levels were directly related to antiinflammatory nuclear receptor PPARγ expression in first episode of psychosis baseline conditions and to proinflammatory nuclear factor nuclear factor κB activity in follow-up conditions, respectively. Conclusions: Our results support the need for integrating cardiovascular healthcare very early after the first episode of psychosis

Analysis of Molecular Networks in the Cerebellum in Chronic Schizophrenia: Modulation by Early Postnatal Life Stressors in Murine Models

Despite the growing importance of the cerebellum as a region highly vulnerable to accumulating molecular errors in schizophrenia, limited information is available regarding altered molecular networks with potential therapeutic targets. To identify altered networks, we conducted one-shot liquid chromatography–tandem mass spectrometry in postmortem cerebellar cortex in schizophrenia and healthy individuals followed by bioinformatic analysis (PXD024937 identifier in ProteomeXchange repository). A total of 108 up-regulated proteins were enriched in stress-related proteins, half of which were also enriched in axonal cytoskeletal organization and vesicle-mediated transport. A total of 142 down-regulated proteins showed an enrichment in proteins involved in mitochondrial disease, most of which were also enriched in energy-related biological functions. Network analysis identified a mixed module of mainly axonal-related pathways for up-regulated proteins with a high number of interactions for stress-related proteins. Energy metabolism and neutrophil degranulation modules were found for down-regulated proteins. Further, two double-hit postnatal stress murine models based on maternal deprivation combined with social isolation or chronic restraint stress were used to investigate the most robust candidates of generated networks. CLASP1 from the axonal module in the model of maternal deprivation was combined with social isolation, while YWHAZ was not altered in either model. METTL7A from the degranulation pathway was reduced in both models and was identified as altered also in previous gene expression studies, while NDUFB9 from the energy network was reduced only in the model of maternal deprivation combined with social isolation. This work provides altered stress- and mitochondrial disease-related proteins involved in energy, immune and axonal networks in the cerebellum in schizophrenia as possible novel targets for therapeutic interventions and suggests that METTL7A is a possible relevant altered stress-related protein in this context

Association of prolactin, oxytocin, and homocysteine with the clinical and cognitive features of a first episode of psychosis over a 1-year follow-up

Background: The clinical debut of schizophrenia is frequently a first episode of psychosis (FEP). As such, there is considerable interest in identifying associations between biological markers and clinical or cognitive characteristics that help predict the progression and outcome of FEP patients. Previous studies showed that high prolactin, low oxytocin, and high homocysteine are factors associated with FEP 6 months after diagnosis, at which point plasma levels were correlated with some clinical and cognitive characteristics. Methods: We reexamined 75 patients at 12 months after diagnosis to measure the evolution of these molecules and assess their association with clinical features. Results: At follow-up, FEP patients had lower prolactin levels than at baseline, and patients treated with risperidone or paliperidone had higher prolactin levels than patients who received other antipsychotic agents. By contrast, no changes in oxytocin and homocysteine plasma levels were observed between the baseline and follow-up. In terms of clinical features, we found that plasma prolactin and homocysteine levels were correlated with the severity of the psychotic symptoms in male FEP patients, suggesting that they might be factors associated with psychotic symptomatology but only in men. Together with oxytocin, these molecules may also be related to sustained attention, verbal ability, and working memory cognitive domains in FEP patients. Conclusion: This study suggests that focusing on prolactin, oxytocin, and homocysteine at a FEP may help select adequate pharmacological treatments and develop new tools to improve the outcome of these patients, where sex should also be borne in mind

Association Between Medication Adherence and Oxidative Stress in Patients With First-Episode Mania

Poor adherence is a major problem in patients with manic episodes that impairs functionality and has unknown effects on oxidative stress. The objective of this study was to analyze the relationship between adherence to medication, severity of symptoms and oxidative stress in a sample of patients with a first episode of mania. A longitudinal, 6-month study was performed in 60 patients, who were classified as adherent and non-adherent to medication (mainly antipsychotics). Blood levels of oxidative stress parameters and expression of the antioxidant nuclear transcription factor NRF2 in mononuclear cells of peripheral blood were assessed at baseline and at the end of follow-up. In addition, clinical symptoms and functioning were evaluated. Linear multivariate regression was used to determine the relationship between adherence, oxidative stress, and clinical symptoms. Finally, 44 patients completed follow-up. The results of this study showed that at 6-month follow-up, adherence was significantly associated with better functioning and reduced clinical symptoms. Additionally, more severe symptoms were associated with increased levels of oxidative stress and antioxidant parameters. At study completion, non-adherents exhibited greater levels of antioxidants than adherent patients. In conclusion, poor adherence to medication is associated with a poorer prognosis in the medium term and causes increased antioxidant response

The influence of oxytocin and prolactin during a first-episode of psychosis: the implication of sex differences, clinical features and cognitive performance

Background: Approximately 3% of the population suffers a first episode of psychosis (FEP), and a high percentage of these patients subsequently relapse. Because the clinical course following a FEP is hard to predict, it is of interest to identify cognitive and biological markers that will help improve the diagnosis, treatment, and outcome of such events and to define new therapeutic targets. Here we analyzed the plasma oxytocin and prolactin levels during an FEP, assessing their correlation with clinical and cognitive features. Methods: The oxytocin and prolactin in plasma was measured in 120 FEP patients and 106 healthy controls, all of whom were subjected to a clinical and neuropsychological assessment. Most patients were under antipsychotics. Statistical analyses aimed to identify factors associated with the FEP and to search for associations between the variables. This study is preliminary and exploratory because the P-values were not corrected for multiple comparisons. Results: FEP patients had less oxytocin, more prolactin, and a poor premorbid IQ, and they performed worse in sustained attention. Male patients with higher prolactin levels experienced more severe psychotic symptoms and required higher doses of antipsychotics. Low oxytocin was associated with poor sustained attention in women, whereas low oxytocin and high prolactin in men correlated with better performance in sustained attention. Conclusion: Low oxytocin, high prolactin, and poor premorbid IQ and sustained attention are factors associated with an FEP, representing potential therapeutic targets in these patients. These biological factors and cognitive domains might play an important role during a FEP, which could help us to develop new strategies that improve the outcomes of this disorder and that should perhaps be gender specific