OXTR polymorphism in depression and completed suicide-A study on a large population sample

Deviant Peer Affiliation, Depression, and Adolescent Non-Suicidal Self-Injury: The Moderating Effect of the OXTR Gene rs53576 Polymorphism

BACKGROUND

Adolescent non-suicidal self-injury (NSSI) has emerged as a progressively widespread and significant public health concern on a global scale. Research has increasingly documented a positive linkage between deviant peer affiliation and adolescent NSSI; however, there is little known about the underlying moderating or mediating mechanism of NSSI. According to the gene × environment interaction perspective, the current study investigated the intermediary function of depression in linking deviant peer affiliation to NSSI among adolescents, while also considering the moderating effect of the OXTR gene rs53576 polymorphism on this intermediary process.

METHODS

A total of 469 adolescents (Meanage = 12.81 years; SD = 0.47 years) anonymously finished the study questionnaires. This study used structural equation modeling analysis to verify a moderated mediation model. Gender, age, and family financial difficulties were used as covariates.

RESULTS

Mediation analyses suggested that the positive connection between deviant peer affiliation and adolescent NSSI was mediated by depression. Moreover, the moderated mediation analyses revealed that deviant peer affiliation increased depression levels, which in turn contributed to increased NSSI among adolescents with the AA genotype. Nevertheless, the correlation failed to reach statistical significance among adolescents possessing the GA and GG genotypes.

CONCLUSIONS

These findings emphasize depression's potential as a bridge linking deviant peer affiliation to adolescent NSSI. The AA genotype of the OXTR gene rs53576 emerges as a critical risk factor in the enhancement of this indirect effect. This study provides valuable perspectives for designing intervention strategies aimed at reducing adolescent NSSI.

Roles of the Oxytocin Receptor (OXTR) in Human Diseases

The oxytocin receptor (OXTR), encoded by the OXTR gene, is responsible for the signal transduction after binding its ligand, oxytocin. Although this signaling is primarily involved in controlling maternal behavior, it was demonstrated that OXTR also plays a role in the development of the nervous system. Therefore, it is not a surprise that both the ligand and the receptor are involved in the modulation of behaviors, especially those related to sexual, social, and stress-induced activities. As in the case of every regulatory system, any disturbances in the structures or functions of oxytocin and OXTR may lead to the development or modulation of various diseases related to the regulated functions, which in this case include either mental problems (autism, depression, schizophrenia, obsessive-compulsive disorders) or those related to the functioning of reproductive organs (endometriosis, uterine adenomyosis, premature birth). Nevertheless, OXTR abnormalities are also connected to other diseases, including cancer, cardiac disorders, osteoporosis, and obesity. Recent reports indicated that the changes in the levels of OXTR and the formation of its aggregates may influence the course of some inherited metabolic diseases, such as mucopolysaccharidoses. In this review, the involvement of OXTR dysfunctions and OXTR polymorphisms in the development of different diseases is summarized and discussed. The analysis of published results led us to suggest that changes in OXTR expression and OXTR abundance and activity are not specific to individual diseases, but rather they influence processes (mostly related to behavioral changes) that might modulate the course of various disorders. Moreover, a possible explanation of the discrepancies in the published results of effects of the OXTR gene polymorphisms and methylation on different diseases is proposed.

Associations between alcohol use and peripheral, genetic, and epigenetic markers of oxytocin in a general sample of young and older adults

INTRODUCTION

Human and nonhuman animal research suggests that greater oxytocin (OT) activity is protective against harmful substance use. Most research on this topic is preclinical, with few studies evaluating the association between substance use and individual differences in the human OT system. The present study sought to fill this gap by evaluating the relationship between alcohol use and multiple biological measures of OT activity in an overall low to moderate-drinking sample.

METHOD

As part of a larger study, generally healthy young (n = 51) and older (n = 53) adults self-reported whether they regularly used alcohol and how much alcohol they consumed per week. Participants also provided blood samples from which peripheral OT, and in an age-heterogeneous subset of participants (n = 56) variation in the oxytocin receptor gene (the OXTR rs53576 polymorphism) and OXTR DNA methylation levels (at cytosine-guanine dinucleotide sites -860, -924, -934), were obtained.

RESULTS

A-allele carriers of the OXTR rs53579 polymorphism were less likely to regularly consume alcohol. Among regular alcohol consumers, number of alcoholic drinks per week was positively associated with peripheral OT in regression models excluding observations of high influence (postdiagnostic models). Number of alcoholic drinks per week was consistently negatively associated with OXTR DNA methylation at site -860; and with OXTR DNA methylation at site -924 in postdiagnostic models.

CONCLUSIONS

The significant associations between alcohol use and individual differences in OT activity support the involvement of the OT system in alcohol use, which most likely reflect the role of OT when alcohol use is under control of its rewarding properties and/or the acute impacts of alcohol on the OT system. Additional research with markers of OT activity and alcohol use, particularly longitudinal, is needed to clarify the bidirectional effects of OT and alcohol use in moderate to harmful drinking and dependence.

The association of oxytocin with major depressive disorder: role of confounding effects of antidepressants

Major depressive disorder is a genetic susceptible disease, and a psychiatric syndrome with a high rate of incidence and recurrence. Because of its complexity concerning etiology and pathogenesis, the cure rate of first-line antidepressants is low. In recent years, accumulative evidences revealed that oxytocin act as a physiological or pathological participant in a variety of complex neuropsychological activities, including major depressive disorder. Six electronic databases (Web of Science, PubMed, Scopus, Google Scholar, CNKI, and Wanfang) were employed for researching relevant publications. At last, 226 articles were extracted. The current review addresses the correlation of the oxytocin system and major depressive disorder. Besides, we summarize the mechanisms by which the oxytocin system exerts potential antidepressant effects, including regulating neuronal activity, influencing neuroplasticity and regeneration, altering neurotransmitter release, down regulating hypothalamic-pituitary-adrenal axis, anti-inflammatory, antioxidation, and genetic effects. Increasing evidence shows that oxytocin and its receptor gene may play a potential role in major depressive disorder. Future research should focus on the predictive ability of the oxytocin system as a biomarker, as well as its role in targeted prevention and early intervention of major depressive disorder.

Association Analysis of 14 Candidate Gene Polymorphism with Depression and Stress among Gestational Diabetes Mellitus

The association of candidate genes and psychological symptoms of depression, anxiety, and stress among women with gestational diabetes mellitus (GDM) in Malaysia was determined in this study, followed by the determination of their odds of getting psychological symptoms, adjusted for socio-demographical background, maternal, and clinical characteristics. Single nucleotide polymorphisms (SNPs) recorded a significant association between SNP of EPHX2 (rs17466684) and depression symptoms (AOR = 7.854, 95% CI = 1.330–46.360) and stress symptoms (AOR = 7.664, 95% CI = 1.579–37.197). Associations were also observed between stress symptoms and SNP of OXTR (rs53576) and (AOR = 2.981, 95% CI = 1.058–8.402) and SNP of NRG1 (rs2919375) (AOR = 9.894, 95% CI = 1.159–84.427). The SNP of EPHX2 (rs17466684) gene polymorphism is associated with depression symptoms among Malaysian women with GDM. SNP of EPHX2 (rs17466684), OXTR (rs53576) and NRG1 (rs2919375) are also associated with stress symptoms.

Infancy onset maltreatment and the development of suicide ideation: An investigation of moderation by oxytocin-related gene polymorphisms

BACKGROUND

Suicide ideation and behavior remains a significant public policy concern. The interpersonal-psychological theory of suicide posits that thwarted belongingness potentiates risk for suicide. Early disruptions in caregiving have documented effects on lifespan social and interpersonal development, and therefore warrants further investigation in suicide research. This novel study investigates risk for suicide ideation conferred by infant-onset child maltreatment and oxytocin genotypes (OXTR and CD38) and tests interactive effects of genetics and early maltreatment experiences.

METHODS

Participants (N = 251) were from a longitudinal follow-up study of emerging adults who participated in a research summer camp program as children (wave 1). Childhood maltreatment was coded from child protective service records and buccal cells were obtained from children and genotyped. At wave 2, self-reported suicide ideation and internalizing symptomatology were obtained.

RESULTS

Maltreatment onset in infancy was significantly related to lifetime suicide ideation. The CD38 gene variation moderated this association such that early onset maltreatment was related to suicide ideation among C-carriers only. The OXTR gene did not relate to lifetime suicide ideation, nor did it moderate early onset maltreatment risk.

LIMITATIONS

This study was conducted with a relatively small sample, necessitating the combination of genotypes into binary groups. Replication is necessary.

CONCLUSIONS

Child maltreatment experienced early in development confers significant risk for lifetime suicide ideation. Furthermore, greater risk for suicide ideation was present for those with specific oxytocin genotypes. These findings further emphasize the importance of preventive interventions aimed at decreasing the incidence of maltreatment and increasing support for high risk families.

The Oxytocin Receptor Gene (OXTR) Variant rs53576 Is Not Related to Emotional Traits or States in Young Adults

Background: To understand the genetic underpinnings of emotion, researchers have studied genetic variants in the oxytocin system, a hormone and neurotransmitter important to socio-emotional functioning. The oxytocin receptor gene (OXTR) variant rs53576 has been associated with emotional traits such as positive affect and related constructs such as optimism and self-esteem. Individuals carrying the A allele (AG and AA genotypes) of rs53576 have been found to score lower in these traits when compared to GG homozygotes, although not always. Given recent mixed evidence regarding this polymorphism, replication of these associations is critical.

Methods: Using a cross-sectional design, the present study tested the association between rs53576 and a wide variety of emotional traits and states in a sample of 611 young adults ages 18 – 25 of various ethnicities (European, Asian, Māori/Pacific Islander, other). Participants completed standard trait measures of positive and negative affect, depressive symptoms, life engagement, psychological well-being, optimism, and self-esteem. They also completed state measures of positive and negative affect and life engagement for 13-days using Internet daily diaries.

Results: Controlling for ethnicity and gender, variation at the OXTR variant rs53576 obtained from blood samples was not related to any of the emotional traits or states. This null finding occurred despite measuring emotions in “near to real time” using daily diaries and having sufficient power to detect a medium effect size difference between homozygous genotype groups.

Conclusion: These findings suggest that variation at the rs53576 locus may not be as involved in emotional differences as initial studies suggested.

Association between serotonin 2A receptor genetic variations, stressful life events and suicide

AIM

Life events are series of events that disrupt a person's psychological equilibrium and may enhance the development of a disorder such as suicide. Several studies have assessed a relationship between 5-hydroxytryptamine (serotonin) 2A receptor (5-HTR2A) gene polymorphisms with an increased risk of suicide. However, there has been no study about the association between three 5-HTR2A gene polymorphisms, A1438G (rs6311), T102C (rs6313) and C1354T (rs6314), suicide, stressful life, and loss events in a same time.

METHODS

Relatives of 191 suicide victims were interviewed using a semi-structured questionnaire designed according to Iranian culture. Venous blood was taken from all subjects for DNA isolation. 5-HTR2A polymorphisms in a total of 191 suicide victims and 218 healthy controls were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Chi-squared and Fisher's exact tests were used to compare genotype and allele frequencies between suicide and control groups. Correction for multiple comparisons was calculated using Bonferroni correction.

RESULTS

There was a significant association between the 102 C/C genotype of 5-HTR2A gene and suicide (к² = 8.700, P = 0.012). Furthermore, we found that suicide victims with a 102 C/C genotype had a significantly higher number of stressful life and loss events (P < 0.05). Genotype and allele distributions of A1438G (rs6311) and C1354T (rs6314) polymorphisms of 5-HTR2A gene showed no differences between suicide victims and control participants and there was no association between genotype distribution and higher number of stressful life and loss events (P > 0.05).

CONCLUSION

Our results suggest that C102T (rs6313) polymorphism of 5-HTR2A gene may be involved in the susceptibility to suicide, higher number of stressful life and loss events, but A1438G (rs6311) and C1354T (rs6314) polymorphisms of 5-HTR2A gene were not associated with suicide, higher number of stressful life and loss events.