Influence of glutathione-related genetic variants on the oxidative stress profile of Mexican patients with psychotic disorders

Objective: The clinical trajectories of patients with psychotic disorders have divergent outcomes, which may result in part from glutathione (GSH)-related high-risk genotypes. We aimed to determine pharmacokinetics of clozapine, GSH levels, GSH peroxidase (GPx) activity, gene variants involved in the synthesis and metabolism of GSH, and their association with psychotic disorders in Mexican patients on clozapine monotherapy and controls. Methods: The sample included 75 patients with psychotic disorders on clozapine therapy and 40 paired healthy controls. Plasma clozapine/N-desmethylclozapine, GSH concentrations, and GPx activity were determined, along with genotyping of GCLC and GSTP1 variants and copy number variations of GSTP1, GSTT1, and GSTM1. Clinical, molecular and biochemical data were analyzed with a logistic regression model. Results: GSH levels were significantly reduced and, conversely, GPx activity was higher among patients than controls. GCLC_GAG-7/9 genotype (OR = 4.3, 95%CI = 1.40-14.31, p = 0.019) and hetero-/homozygous genotypes of GCLC_rs761142 (OR = 6.09, 95%CI = 1.93-22.59, p = 0.003) were found to be risk factors for psychosis. The genetic variants were not related to clozapine/N-desmethylclozapine levels or metabolic ratio. Conclusions: GCLC variants were associated with the oxidative stress profile of patients with psychotic disorders, raising opportunities for intervention to improve their antioxidant defenses. Further studies with larger samples should explore this proposal.

Las orexinas como biomarcadores para demencia tipo Alzheimer y relación con síntomas neuropsiquiátricos / Orexins as biomarkers for Alzheimer dementia and their relationship with neuropsychiatric symptoms

RESUMEN: Los biomarcadores más estudiados en la demencia tipo Alzheimer (DA) son los niveles elevados de Aβ42 y de proteína Tau en líquido cefalorraquídeo. Dada la complejidad de la sintomatología cognitiva y síntomas neuropsiquiátricos (SNP) de esta patología, algunos estudios recientes proponen sustancias como las orexinas, como blanco terapéutico de DA y SNP. El presente trabajo tiene como objetivo revisar publicaciones científicas recientes que hayan analizado la asociación entre orexinas, SNP y DA en humanos, algunos modelos animales y que hayan evaluado a las orexinas como posibles biomarcadores tanto para investigación como en el área clínica. En esta revisión también se describen los estudios que sugieren a las orexinas como un posible biomarcador en la DA, dada su relación con el Aβ42 y la proteína Tau, y otros estudios que las asocian con presencia de SNP, especialmente alteración del sueño. Se plantea la hipótesis de que la presencia de SNP en DA se asocia con las orexinas, debido a que este sistema influye en el funcionamiento hipotalámico y de forma indirecta en áreas cerebrales que regulan el comportamiento. Sin embargo, aún falta mayor investigación, principalmente de estudios longitudinales para conocer claramente la influencia de las orexinas en los SNP.

ABSTRACT The most studied biomarkers in Alzheimer's dementia (AD) are elevated levels of Aβ42 and Tau protein in cerebrospinal fluid. Given the complexity of the cognitive symptomatology and neuropsychiatric symptoms (NPS) of this pathology, some recent studies propose substances such as orexins as a therapeutic target for AD and NPS. The present work aims to review recent scientific publications that have analyzed the association between orexins, PNS and AD in humans. There are some animal models that have evaluated orexins as possible biomarkers both for research and in the clinical area. This review also describes studies that suggest orexins as possible biomarkers in AD, given their relationship with Aβ42 and Tau protein, and other studies that associate them with the presence of SNPs, especially sleep disturbance. It is hypothesized that the presence of SNPs in AD is associated with orexins, because this system influences hypothalamic functioning and indirectly in brain areas that regulate behavior. However, further research is still lacking, mainly longitudinal studies to clearly know the influence of orexins on SNPs.

Brain Gene Expression-DNA Methylation Correlation in Suicide Completers: Preliminary Results

Abstract Background: Gene expression alterations have been implicated in suicide pathology. However, the study of the regulatory effect of DNA methylation on gene expression in the suicidal brain has been restricted to candidate genes. Objective: The objective of the study was to identify genes whose expression levels are correlated with DNA methylation in the prefrontal cortex of suicides. Methods: Postmortem prefrontal cortex samples from 21 suicides and six non-suicides were collected. Transcriptomic and DNA methylation profiles were evaluated with microarrays; cis correlations between gene expression and CpG methylation were screened. We then analyzed the presence of transcription factor (TF) binding sites (TFBS) at CpG sites correlated with gene expression. Gene expression of TFs involved in neurodevelopmental binding to predicted TFBS was determined in the BrainSpan database. Results: We identified 22 CpG sites whose methylation levels correlated with gene expression in the prefrontal cortex of suicides. Genes annotated to identified CpG sites were involved in neurodevelopment (BBS4, NKX6-2, AXL, CTNND1, and MBP) and polyamine metabolism (polyamine oxidase [PAOX]). Such correlations were not detected in the non-suicide group. Nine TFs (USF1, TBP, SF1, NRF1, RFX1, SP3, PKNOX1, MAZ, and POU3F2) showed differential expression in pre- and post-natal developmental periods, according to BrainSpan database. Conclusions: The integration of different omic technologies provided novel candidates for the investigation of genes whose expression is altered in the suicidal brain and their potential regulatory mechanisms. (REV INVEST CLIN. 2020;72(5):283-92)

Displasia ectodérmica hipohidrótica ligada al cromosoma X de novo por variante recurrente en un paciente mexicano / X-linked hypohidrotic ectodermal dysplasia by a de novo recurrent variant in a Mexican patient

Resumen Introducción: Las displasias ectodérmicas son un grupo de genodermatosis que se caracterizan por distrofia de las estructuras derivadas del ectodermo. De ellas, la variedad más común es la hipohidrótica, con una incidencia de 7/100,000 nacidos vivos observada en todos los grupos étnicos. La displasia ectodérmica hipohidrótica tiene distintas etiologías. La presentación más frecuente es la asociada a un patrón de herencia ligado al cromosoma X, causada por variantes patogénicas del gen EDA en Xq13.1. EDA codifica a la ectodisplasina A, una molécula de señalización que participa en la comunicación epitelio-mesénquima durante el desarrollo de la piel y los anexos. Caso clínico: Varón de 6 años con las características clínicas cardinales de la displasia ectodérmica hipohidrótica ligada al cromosoma X (DEHLX), que incluyen hipotricosis, oligodoncia e hipohidrosis. El análisis del gen EDA por secuenciación directa mostró la presencia de la variante patogénica c.466C>T, p.Arg156Cys, rs132630313 con presentación de novo en el paciente. Esta variante ya ha sido reportada en diferentes poblaciones, incluyendo familias mexicanas, y constituye un punto caliente para mutación en EDA. Se analizaron los hallazgos clínicos, la etiología y el manejo de la DEHLX, en la que de manera reciente se ha planteado la posibilidad de otorgar tratamiento prenatal para prevenir sus manifestaciones clínicas. Conclusiones: Se pone de relevancia que el análisis molecular en pacientes con DEHLX corrobora el diagnóstico clínico y permite brindar asesoramiento genético con bases moleculares.

Abstract Background: Ectodermal dysplasias are a group of genodermatoses characterized by dystrophy of ectodermal derived structures. The most frequent presentation of the ectodermal dysplasias is the hypohidrotic type, which has an incidence of 7/100,000 newborns and has been described in all ethnic groups. The hypohidrotic ectodermal dysplasia (HED) has different etiologies, and it is more frequently associated with an X-linked pattern of inheritance caused by pathogenic variants of the EDA gene in Xq13.1. EDA encodes the protein ectodisplasin A, a signal molecule which participates in epithelium and mesenchymal development of the skin. Case report: A 6 year-old male patient with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. The direct sequencing analysis of EDA in our patient detected a de novo pathogenic variant, c.466C>T, p.Arg156Cys, rs132630313. This variant has been previously described in different ethnic groups, including Mexican families, and is considered a mutational hotspot. The clinical characteristics, etiology and management of the X-linked HED, including the possibility of prenatal therapy in order to avoid the clinical manifestations are discussed. Conclusions: The molecular analysis in patients with X-linked HED is of relevance, as it enables to confirm the clinical diagnosis and also, it allows a genetic assessment with molecular bases.