Integrative Genomic-Epigenomic Analysis of Clozapine-Treated Patients with Refractory Psychosis.

Clozapine (CLZ) is the only antipsychotic drug that has been proven to be effective in patients with refractory psychosis, but it has also been proposed as an effective mood stabilizer; however, the complex mechanisms of action of CLZ are not yet fully known. To find predictors of CLZ-associated phenotypes (i.e., the metabolic ratio, dosage, and response), we explore the genomic and epigenomic characteristics of 44 patients with refractory psychosis who receive CLZ treatment based on the integration of polygenic risk score (PRS) analyses in simultaneous methylome profiles. Surprisingly, the PRS for bipolar disorder (BD-PRS) was associated with the CLZ metabolic ratio (pseudo-R2 = 0.2080, adjusted p-value = 0.0189). To better explain our findings in a biological context, we assess the protein-protein interactions between gene products with high impact variants in the top enriched pathways and those exhibiting differentially methylated sites. The GABAergic synapse pathway was found to be enriched in BD-PRS and was associated with the CLZ metabolic ratio. Such interplay supports the use of CLZ as a mood stabilizer and not just as an antipsychotic. Future studies with larger sample sizes should be pursued to confirm the findings of this study.

Psicofarmacología del suicidio II parte: Estabilizadores del ánimo y suicidio / Mood stabilizers and suicide: Part II

Lithium and anticonvulsants have been widely used as mood stabilizers (MS) in bipolar affective disorder (BAD), showing a reduction of suicide risk, even more, the anti-suicidal effect of lithium would be independent of its stabilizer property. The action mechanisms of the drug are not completely known and clinical research is hampered due to the heterogeneity of the studied samples, however, some mechanisms related to neurotransmitters metabolism and neurotrophic and neuroprotective factors have been proposed in order to explain its effect. Despite the current decline in the use of lithium as a MS it remains as the anti-suicidal drug of choice in bipolar patients.

El litio y los anticonvulsivantes han sido ampliamente empleados como estabilizadores del ánimo (EA) en el trastorno afectivo bipolar (TAB), demostrando además una reducción del riesgo de suicidio. En el caso particular del litio, dicho efecto sería independiente de su acción estabilizadora. Si bien los mecanismos de acción de la droga no son completamente conocidos y la investigación clínica se ve dificultada debido a la heterogeneidad de las muestras estudiadas, se han propuesto distintas vías que explicarían su efecto, relacionadas con el metabolismo de los neurotransmisores y con factores neurotróficos y neuroprotectores. Pese a la disminución actual en el uso del litio como EA, continúa siendo el fármaco antisuicida de elección en pacientes bipolares.

Targeting mitochondrially mediated plasticity to develop improved therapeutics for bipolar disorder.

INTRODUCTION: Bipolar disorder (BPD) is a severe illness with few treatments available. Understanding BPD pathophysiology and identifying potential relevant targets could prove useful for developing new treatments. Remarkably, subtle impairments of mitochondrial function may play an important role in BPD pathophysiology. AREAS COVERED: This article focuses on human studies and reviews evidence of mitochondrial dysfunction in BPD as a promising target for the development of new, improved treatments. Mitochondria are crucial for energy production, generated mainly through the electron transport chain (ETC) and play an important role in regulating apoptosis and calcium (Ca²âº) signaling as well as synaptic plasticity. Mitochondria move throughout the neurons to provide energy for intracellular signaling. Studies showed polymorphisms of mitochondria-related genes as risk factors for BPD. Postmortem studies in BPD also show decreased ETC activity/expression and increased nitrosative and oxidative stress (OxS) in patient brains. BPD has been also associated with increased OxS, Ca²âº dysregulation and increased proapoptotic signaling in peripheral blood. Neuroimaging studies consistently show decreased energy levels and pH in brains of BPD patients. EXPERT OPINION: Targeting mitochondrial function, and their role in energy metabolism, synaptic plasticity and cell survival, may be an important avenue for development of new mood-stabilizing agents.

Histone deacetylase activity and brain-derived neurotrophic factor (BDNF) levels in a pharmacological model of mania

Objective: In the present study, we aimed to examine the effects of repeated D-amphetamine (AMPH) exposure, a well-accepted animal model of acute mania in bipolar disorder (BD), and histone deacetylase (HDAC) inhibitors on locomotor behavior and HDAC activity in the prefrontal cortex (PFC) and peripheral blood mononuclear cells (PBMCs) of rats. Moreover, we aimed to assess brain-derived neurotrophic factor (BDNF) protein and mRNA levels in these samples. Methods: We treated adult male Wistar rats with 2 mg/kg AMPH or saline intraperitoneally for 14 days. Between the 8th and 14th days, rats also received 47.5 mg/kg lithium (Li), 200 mg/kg sodium valproate (VPT), 2 mg/kg sodium butyrate (SB), or saline. We evaluated locomotor activity in the open-field task and assessed HDAC activity in the PFC and PBMCs, and BDNF levels in the PFC and plasma. Results: AMPH significantly increased locomotor activity, which was reversed by all drugs. This hyperactivity was associated with increased HDAC activity in the PFC, which was partially reversed by Li, VPT, and SB. No differences were found in BDNF levels. Conclusion: Repeated AMPH administration increases HDAC activity in the PFC without altering BDNF levels. The partial reversal of HDAC increase by Li, VPT, and SB may account for their ability to reverse AMPH-induced hyperactivity. .