Effect of the Nature of Subsequent Environment on Oxytocin and Cortisol Secretion in Maltreated Children

Subclinical structural atypicality of retinal thickness and its association with gray matter volume in the visual cortex of maltreated children

Childhood maltreatment is reportedly associated with atypical gray matter structures in the primary visual cortex (V1). This study explores the hypothesis that retinal structures, the sensory organs of vision, are associated with brain atypicality and child maltreatment and examines their interrelation. General ophthalmologic examinations, visual cognitive tasks, retinal imaging, and structural magnetic resonance imaging (MRI) were conducted in children and adolescents aged 9-18 years with maltreatment experiences (CM) and typically developing (TD) children. The retinal nerve fiber layer (RNFL), the most superficial of the ten distinct retinal layers, was found to be significantly thinner in both eyes in CM. While whole-brain analysis using Voxel-based morphometry revealed a significantly larger gray matter volume (GMV) in the thalamus in CM, no significant correlation with RNFL thickness was observed. However, based on region-of-interest analysis, a thinner RNFL was associated with a larger GMV in the right V1. Although it cannot be ruled out that this outcome resulted from maltreatment alone, CM demonstrated subclinical structural atypicality in the retina, which may also correlate with the immaturity of V1 development. Examination of retinal thickness offers a novel clinical approach to capturing characteristics associated with childhood maltreatment.

Out of touch? How trauma shapes the experience of social touch - Neural and endocrine pathways

Trauma can shape the way an individual experiences the world and interacts with other people. Touch is a key component of social interactions, but surprisingly little is known about how trauma exposure influences the processing of social touch. In this review, we examine possible neurobiological pathways through which trauma can influence touch processing and lead to touch aversion and avoidance in trauma-exposed individuals. Emerging evidence indicates that trauma may affect sensory touch thresholds by modulating activity in the primary sensory cortex and posterior insula. Disturbances in multisensory integration and oxytocin reactivity combined with diminished reward-related and anxiolytic responses may induce a bias towards negative appraisal of touch contexts. Furthermore, hippocampus deactivation during social touch may reflect a dissociative state. These changes depend not only on the type and severity of the trauma but also on the features of the touch. We hypothesise that disrupted touch processing may impair social interactions and confer elevated risk for future stress-related disorders.

The neurobiological effects of childhood maltreatment on brain structure, function, and attachment

Childhood maltreatment is a risk factor for psychopathologies, and influences brain development at specific periods, particularly during early childhood and adolescence. This narrative review addresses phenotypic alterations in sensory systems associated with specific types of childhood maltreatment exposure, periods of vulnerability to the neurobiological effects of maltreatment, and the relationships between childhood maltreatment and brain structure, function, connectivity, and network architecture; psychopathology; and resilience. It also addresses neurobiological alterations associated with maternal communication and attachment disturbances, and uses laboratory-based measures during infancy and case-control studies to elucidate neurobiological alterations in reactive attachment disorders in children with maltreatment histories. Moreover, we review studies on the acute effects of oxytocin on reactive attachment disorder and maltreatment and methylation of oxytocin regulatory genes. Epigenetic changes may play a critical role in initiating or producing the atypical structural and functional brain alterations associated with childhood maltreatment. However, these changes could be reversed through psychological and pharmacological interventions, and by anticipating or preventing the emergence of brain alterations and subsequent psychopathological risks.

Oxytocin: An Old Hormone, A Novel Psychotropic Drug And Possible Use In Treating Psychiatric Disorders

BACKGROUND

Oxytocin is a nonapeptide synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Historically, this molecule has been involved as a key factor in the formation of infant attachment, maternal behavior and pair bonding and, more generally, in linking social signals with cognition, behaviors and reward. In the last decades, the whole oxytocin system has gained a growing interest as it was proposed to be implicated in etiopathogenesis of several neurodevelopmental and neuropsychiatric disorders.

METHODS

With the main goal of an in-depth understanding of the oxytocin role in the regulation of different functions and complex behaviors as well as its intriguing implications in different neuropsychiatric disorders, we performed a critical review of the current state of art. We carried out this work through PubMed database up to June 2021 with the search terms: 1) "oxytocin and neuropsychiatric disorders"; 2) "oxytocin and neurodevelopmental disorders"; 3) "oxytocin and anorexia"; 4) "oxytocin and eating disorders"; 5) "oxytocin and obsessive-compulsive disorder"; 6) "oxytocin and schizophrenia"; 7) "oxytocin and depression"; 8) "oxytocin and bipolar disorder"; 9) "oxytocin and psychosis"; 10) "oxytocin and anxiety"; 11) "oxytocin and personality disorder"; 12) "oxytocin and PTSD".

RESULTS

Biological, genetic, and epigenetic studies highlighted quality and quantity modifications in the expression of oxytocin peptide or in oxytocin receptor isoforms. These alterations would seem to be correlated with a higher risk of presenting several neuropsychiatric disorders belonging to different psychopathological spectra. Collaterally, the exogenous oxytocin administration has shown to ameliorate many neuropsychiatric clinical conditions.

CONCLUSION

Finally, we briefly analyzed the potential pharmacological use of oxytocin in patient with severe symptomatic SARS-CoV-2 infection due to its anti-inflammatory, anti-oxidative and immunoregulatory properties.

Alterations in oxytocin and vasopressin in men with problematic pornography use: The role of empathy

BACKGROUND

Addictive behaviors share clinical, genetic, neurobiological and phenomenological parallels with substance addictions. Despite the prevalence of compulsive sexual behaviors, particularly problematic pornography use (PPU), how neuroendocrine systems relate to PPU is not well understood. Preclinical studies demonstrate alterations in oxytocin and arginine vasopressin (AVP) function in animal models of addiction, but no human study has tested their involvement in PPU.

METHOD

Participants included 122 males; 69 reported PPU, and 53 were demographically-matched participants without PPU. Plasma oxytocin and AVP levels and oxytocin-to-AVP balance were measured at baseline. Salivary oxytocin was assessed at baseline and in response to four videos depicting neutral/positive social encounters. Participants reported on empathy and psychiatric symptoms.

RESULTS

Baseline plasma AVP levels were elevated in men with PPU, and the ratio of oxytocin-to-vasopressin suggested AVP dominance. Men with PPU reacted with greater oxytocin increases to presentation of neutral/positive social stimuli. Decreased empathic tendencies were found in men with PPU, and this reduced empathy mediated links between oxytocin and pornography-related hypersexuality. Structural equation modeling revealed three independent paths to pornography-related hypersexuality; two direct paths via increased AVP and higher psychiatric symptoms and one indirect path from oxytocin to pornography-related hypersexuality mediated by diminished empathy.

CONCLUSIONS

Findings are among the first to implicate neuropeptides sustaining mammalian attachment in the pathophysiology of pornography-related hypersexuality and describe a neurobiological mechanism by which oxytocin-AVP systems and psychiatric symptomatology may operate to reduce empathy and lead to pornography-related hypersexuality.

A multi-modal MRI analysis of brain structure and function in relation to OXT methylation in maltreated children and adolescents

Child maltreatment dysregulates the brain's oxytocinergic system, resulting in dysfunctional attachment patterns. However, how the oxytocinergic system in children who are maltreated (CM) is epigenetically affected remains unknown. We assessed differences in salivary DNA methylation of the gene encoding oxytocin (OXT) between CM (n = 24) and non-CM (n = 31), alongside its impact on brain structures and functions using multi-modal brain imaging (voxel-based morphometry, diffusion tensor imaging, and task and resting-state functional magnetic resonance imaging). We found that CM showed higher promoter methylation than non-CM, and nine CpG sites were observed to be correlated with each other and grouped into one index (OXTmi). OXTmi was significantly negatively correlated with gray matter volume (GMV) in the left superior parietal lobule (SPL), and with right putamen activation during a rewarding task, but not with white matter structures. Using a random forest regression model, we investigated the sensitive period and type of maltreatment that contributed the most to OXTmi in CM, revealing that they were 5-8 years of age and physical abuse (PA), respectively. However, the presence of PA (PA+) was meant to reflect more severe cases, such as prolonged exposure to multiple types of abuse, than the absence of PA. PA+ was associated with significantly greater functional connectivity between the right putamen set as the seed and the left SPL and the left cerebellum exterior. The results suggest that OXT promoter hypermethylation may lead to the atypical development of reward and visual association structures and functions, thereby potentially worsening clinical aspects raised by traumatic experiences.

Association Between Accumulation of Child Maltreatment and Salivary Oxytocin Level Among Japanese Adolescents

Background: Child maltreatment is related to oxytocin (OT), which is related to social functioning. It may hamper the OT level to avoid a harmful situation and increase the OT level to adapt to the situation using a tend-and-befriend stress reaction. Objective: This study aims to examine the association between the accumulation of moderate-severe childhood maltreatment and salivary OT levels in Japanese adolescents. Participants: We used convenience samples of adolescents living in an institution (n = 31) and those living with their parents (n = 46). Methods: Child maltreatment experiences were measured with the Childhood Trauma Questionnaire. The salivary OT levels were assessed by enzyme linked immunosorbent assay. A multivariate regression analysis was performed to see the association between the accumulation of child maltreatment types and the salivary OT levels adjusted for covariates (i.e., age, sex, and duration of institutionalization). Results: Physical abuse was associated with higher OT, while emotional neglect showed an inverse association with OT. OT was the lowest with one maltreatment type group, which was significantly lower than the non-maltreatment group. As the number of maltreatment types increased from one maltreatment type to 2-3 types and to 4-5 types, OT also increased. This U-shaped association between the number of maltreatment types and OT was confirmed with the significant result of a square term of number of maltreatment type in the model (p = 0.012). Conclusion: We found herein a U-shaped association between the accumulation of child maltreatment and salivary OT levels. Also, different types of maltreatment had varied effects on the salivary OT. Further study is needed to elucidate the non-linear association between child maltreatment and OT levels.

Women's Cortisol Stress Responsivity, Sexual Arousability, and Sexual History

Life history theory and the adaptive calibration model state that characteristics of one's early environment influence individual differences in both neuroendocrine reactivity to stress and sexual risk-taking behavior. However, few studies have directly examined the relationship between neuroendocrine reactivity to stress and risky sexual behavior. This study used multilevel modeling to test whether cortisol reactivity and recovery in response to laboratory stress were associated with women's history of sexual behavior and their sexual arousability in response to laboratory sexual stimuli. Participants were 65 women (35% heterosexual, 44% bisexual, and 21% lesbian) who completed two laboratory sessions, two weeks apart. Women's self-reported sexual arousability to sexual stimuli interacted with their sexual abuse history to predict their trajectories of cortisol stress reactivity and recovery. Cortisol reactivity and recovery were not associated with women's sexual risk taking, such as the age of sexual debut, sociosexuality, or lifetime number of sexual partners.

Development of Social Attention and Oxytocin Levels in Maltreated Children

Child maltreatment (CM) is a major risk factor for various psychopathologies but also adversely affects social development. Research on oxytocin (OT) is currently drawing attention as an endocrine basis for social development. In this study, we investigated the relationship between visual attention to social cues and salivary OT levels in children exposed to CM. The results revealed that the CM group had a significantly lower percentage of gaze fixation for the human face eye area and lower salivary OT levels compared to the typical development group. Moreover, a path analysis suggested that gaze fixation for the eye area was a mediator of the relationship between salivary OT levels and social-emotional problems in the CM group. These results suggest that lower endogenous OT levels in maltreated children may lead to atypical development of their visual attention to eyes as a social cue, resulting in social-emotional problems.

How do hypothalamic nonapeptides shape youth's sociality? A systematic review on oxytocin, vasopressin and human socio-emotional development

The hypothalamic nonapeptides oxytocin and vasopressin are important modulators of socio-affective behaviours in a wide variety of animal species, including humans. Nevertheless, there is little research addressing their possible roles on socio-affective dimensions of human behaviour across development, during which considerable behavioural and physiological change occurs. Questions still remain about the extent to which findings from adults may directly apply to earlier phases of human development. In this article, we systematically summarize and discuss all existing studies investigating the developmental association of endogenous levels of hypothalamic neuropeptides oxytocin and vasopressin with human social behaviour or on its disruption in paediatric populations. Evidence is sparse insofar as there are still relatively few developmental studies and limited due to correlational research designs and unreliability of methods currently used for neuropeptide measurements in biological fluids. The findings to date generally converge with adult evidence, but also suggest that important differences between age stages may exist. Further studies focusing these differences may prove critical for informing drug development for socio-affective deficits in paediatric populations.

The Associations Between Oxytocin and Trauma in Humans: A Systematic Review

Studies have shown that traumatic experiences may affect hormonal systems mediated by the hypothalamic-pituitary-adrenal (HPA) axis and the oxytocinergic system. This effect is the result of long-term impairments in hypothalamic structures and negative feedback mechanisms within the HPA axis, structures that mediate the response to stress. This deregulation reduces the production and release of cortisol and oxytocin (OXT), which may alter stress responses and lead to increased vulnerability to impairments from stressful experiences. The presence of gene polymorphisms might also have an impact on the vulnerability to psychopathology. We made a systematic review of articles dealing with the relationship between OXT and traumatic emotional experiences in humans. Thirty-five studies were reviewed and significant associations between experiences of emotional trauma (ET) and OXT were found. The main results showed that the presence of ET and post-traumatic stress disorder (PTSD) is strongly associated with reductions in endogenous OXT, and also that the acute effects of OXT administrations in individuals with ET tend to be anxiolytic only in less severe forms. In victims of recent traumatic experiences (RTE), OXT increased the re-experience of traumas and restored the function of different neural networks associated with fear control/extinction in PTSD patients. The results available also suggest that gene receptor polymorphisms may have a protective function in different outcomes after the experience of traumatic events. We conclude that the relationship between ET and OXT is multifaceted, complex, and mediated by contextual and individual factors. Directions for future studies are suggested considering the gaps in the available literature.