A SNP, Gene, and Polygenic Risk Score Approach of Oxytocin-Vasopressin Genes in Adolescents' Loneliness

The Effect of Peer Relationships on Adolescent Loneliness: The Role of Psychological Resilience and the OXTR Gene

Background

Based on the gene-environment interaction paradigm, this study explored the effect of peer relationships on adolescent loneliness and the role of psychological resilience and the oxytocin receptor gene (OXTR).

Methods

A survey was conducted in a sample of 619 adolescents, and their oral cells were collected for DNA extraction and genotyping.

Results

The results showed that (1) both peer relationships and psychological resilience significantly affected adolescent loneliness; (2) psychological resilience partially mediated the relationship between peer relationships and loneliness in adolescents; (3) OXTR gene rs53576 polymorphism moderated both the first and second half of the indirect pathway of the mediation model. Specifically, carriers of the rs53576 polymorphism A/A genotype showed a significantly enhanced effect of peer relationships on adolescent psychological resilience, while carriers of the rs53576 polymorphism G/G genotype showed a significantly enhanced effect of psychological resilience on adolescent loneliness.

Conclusion

These findings helped elucidate the developmental mechanisms of adolescent loneliness in terms of peer relationships, psychological resilience, and OXTR gene polymorphisms.

Neurogenetics and Epigenetics of Loneliness

Loneliness, an established risk factor for both, mental and physical morbidity, is a mounting public health concern. However, the neurobiological mechanisms underlying loneliness-related morbidity are not yet well defined. Here we examined the role of genes and associated DNA risk polymorphic variants that are implicated in loneliness via genetic and epigenetic mechanisms and may thus point to specific therapeutic targets. Searches were conducted on PubMed, Medline, and EMBASE databases using specific Medical Subject Headings terms such as loneliness and genes, neuro- and epigenetics, addiction, affective disorders, alcohol, anti-reward, anxiety, depression, dopamine, cancer, cardiovascular, cognitive, hypodopaminergia, medical, motivation, (neuro)psychopathology, social isolation, and reward deficiency. The narrative literature review yielded recursive collections of scientific and clinical evidence, which were subsequently condensed and summarized in the following key areas: (1) Genetic Antecedents: Exploration of multiple genes mediating reward, stress, immunity and other important vital functions; (2) Genes and Mental Health: Examination of genes linked to personality traits and mental illnesses providing insights into the intricate network of interaction converging on the experience of loneliness; (3) Epigenetic Effects: Inquiry into instances of loneliness and social isolation that are driven by epigenetic methylations associated with negative childhood experiences; and (4) Neural Correlates: Analysis of loneliness-related affective states and cognitions with a focus on hypodopaminergic reward deficiency arising in the context of early life stress, eg, maternal separation, underscoring the importance of parental support early in life. Identification of the individual contributions by various (epi)genetic factors presents opportunities for the creation of innovative preventive, diagnostic, and therapeutic approaches for individuals who cope with persistent feelings of loneliness. The clinical facets and therapeutic prospects associated with the current understanding of loneliness, are discussed emphasizing the relevance of genes and DNA risk polymorphic variants in the context of loneliness-related morbidity.

Physical activity associates empathy in Japanese young adults with specific gene variations of oxytocin receptor and vasopressin V1B receptor

BACKGROUND

Empathy, consisting of cognitive empathy and affective empathy, is essential for creating relationships with others. Since the genetic polymorphism of oxytocin receptor (OXTR) and arginine-vasopressin V1B receptor (AVPR1B) relate to prosocial behavior and empathy, it would need to innovate strategies for treating human empathy by considering individual genetic variations. Physical activity is expected as a possible strategy; here, we investigated the influences of genetic polymorphisms in OXTR SNP rs53576 and AVPR1B SNP rs28373064, on the relationships of self-reported empathy with physical activity.

METHODS

The saliva is collected from a hundred Japanese college students for determining the individual polymorphism of OXTR SNP rs53576 (AA, AG, or GG genotype) and AVPR1B SNP rs28373064 (TT, TC, or CC genotype). In addition, the participants' self-reported cognitive and affective empathy, amounts of physical activity, and sitting time were evaluated with questionaries.

RESULTS

The participants with OXTR SNP rs53576 GG genotype showed a significant negative correlation between sitting time and cognitive empathy adjusted by age, gender, and sports experience. Further, there was a trend to correlate between physical activity amounts and cognitive empathy in the participants carrying the G variant in OXTR SNP rs53576 (AG or GG). As for AVPR1B SNP rs28373064, the persons with TT genotype exhibited a negative correlation trend between sitting time and cognitive empathy.

CONCLUSIONS

There are possible correlations between the self-reported cognitive empathy and physical activity amounts in the persons carrying the G variant of OXTR rs53576 or with the TT genotype for AVPR1B SNP rs28373064.

Salivary and plasmatic oxytocin are not reliable trait markers of the physiology of the oxytocin system in humans

Single measurements of salivary and plasmatic oxytocin are used as indicators of the physiology of the oxytocin system. However, questions remain about whether they are sufficiently stable to provide valid trait markers of the physiology of the oxytocin system, and whether salivary oxytocin can accurately index its plasmatic concentrations. Using radioimmunoassay, we measured baseline plasmatic and/or salivary oxytocin from two independent datasets. We also administered exogenous oxytocin intravenously and intranasally in a triple dummy, within-subject, placebo-controlled design and compared baseline levels and the effects of routes of administration. Our findings question the use of single measurements of baseline oxytocin concentrations in saliva and plasma as valid trait markers of the physiology of the oxytocin system in humans. Salivary oxytocin is a weak surrogate for plasmatic oxytocin. The increases in salivary oxytocin observed after intranasal oxytocin most likely reflect unabsorbed peptide and should not be used to predict treatment effects.