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

A Hypothalamic Perspective of Human Socioemotional Behavior

Historical evidence from stimulation and lesion studies in animals and humans demonstrated a close association between the hypothalamus and typical and atypical socioemotional behavior. A central hypothalamic contribution to regulation of socioemotional responses was also provided indirectly by studies on oxytocin and arginine vasopressin. However, a limited number of studies have so far directly investigated the contribution of the hypothalamus in human socioemotional behavior. To reconsider the functional role of the evolutionarily conserved hypothalamic region in regulating human social behavior, here I provide a synthesis of neuroimaging investigations showing that the hypothalamus is involved in multiple and diverse facets of human socioemotional behavior through widespread functional interactions with other cortical and subcortical regions. These neuroimaging findings are then integrated with recent optogenetics studies in animals demonstrating that the hypothalamus plays a more active role in eliciting socioemotional responses and is not simply a downstream effector of higher-level brain systems. Building on the aforementioned evidence, the hypothalamus is argued to substantially contribute to a continuum of human socioemotional behaviors promoting survival and preservation of the species that extends from exploratory and approaching responses facilitating social bonding to aggressive and avoidance responses aimed to protect and defend formed relationships.

Type 1 melanocortin receptors in pro-opiomelanocortin-, vasopressin-, and oxytocin-immunopositive neurons in different areas of mouse brain

Information on the localization of the Type 1 melanocortin receptors (MC1Rs) in different regions of the brain is very scarce. As a result, the role of MC1Rs in the functioning of brain neurons and in the central regulation of physiological functions has not been studied. This work aimed to study the expression and distribution of MС1Rs in different brain areas of female C57Bl/6J mice. Using real-time polymerase chain reaction, we demonstrated the Mс1R gene expression in the cerebral cortex, midbrain, hypothalamus, medulla oblongata, and hippocampus. Using an immunohistochemical approach, we showed the MС1R localization in neurons of the hypothalamic arcuate, paraventricular and supraoptic nuclei, nucleus tractus solitarius (NTS), dorsal hippocampus, substantia nigra, and cerebral cortex. Using double immunolabeling, the MC1Rs were visualized on the surface and in the bodies and outgrowths of pro-opiomelanocortin (POMC)-immunopositive neurons in the hypothalamic arcuate nucleus, NTS, hippocampal CA3 and CA1 regions, and cerebral cortex. Co-localization with POMC indicates that MC1R, like MC3R, is able to function as an autoreceptor. In the paraventricular and supraoptic nuclei, MC1Rs were visualized on the surface and in the cell bodies of vasopressin- and oxytocin-immunopositive neurons, indicating a relationship between hypothalamic MC1R signaling and vasopressin and oxytocin production. The data obtained indicate a wide distribution of MC1Rs in different areas of the mouse brain and their localization in POMC-, vasopressin- and oxytocin-immunopositive neurons, which may indicate the participation of MC1Rs in the control of many physiological processes in the central nervous system.

Social zebrafish: Danio rerio as an emerging model in social neuroendocrinology

The fitness benefits of social life depend on the ability of animals to affiliate with others and form groups, on dominance hierarchies within groups that determine resource distribution, and on cognitive capacities for recognition, learning and information transfer. The evolution of these phenotypes is coupled with that of neuroendocrine mechanisms, but the causal link between the two remains underexplored. Growing evidence from our research group and others demonstrates that the tools available in zebrafish, Danio rerio, can markedly facilitate progress in this field. Here, we review this evidence and provide a synthesis of the state-of-the-art in this model system. We discuss the involvement of generalized motivation and cognitive components, neuroplasticity and functional connectivity across social decision-making brain areas, and how these are modulated chiefly by the oxytocin-vasopressin neuroendocrine system, but also by reward-pathway monoamine signaling and the effects of sex-hormones and stress physiology.

Genetic and epigenetic effects on couple adjustment in context of romantic relationship: A scoping systematic review

Introduction: Couples' relationships defined by a complex interaction between the two partners and their intrapersonal traits. Romantic; relationships and love are associated with marital satisfaction and stability, as well as couples' happiness and health. Personality traits influence romantic relationships and, personality influenced by genetical and non-genetically factors. The roles of non-genetically factors such as socioeconomic position and external appearance have revealed in determining the quality of romantic relationships. Methods: We; performed a scoping systematic review to assess the association between genetics and epigenetic factors and romantic relationship. Relevant articles were identified by PubMed, EMBASE, Web of Science, Scopus, and the APA PsycInfo searching between inception and 4 June 2022. Results: Different studies evaluated the associated polymorphisms in 15 different genes or chromosomal regions. In the first step; we classified them into four groups: (1) Oxytocin-related signaling pathway (OXTR, CD38, and AVPR1A); (2) Serotonin-related signaling pathway (SLC6A4, HTR1A, and HTR2A); (3) Dopamine and catecholamine-related signaling pathway (DRD1, DRD2, DRD4, ANKK1, and COMT); and (4) other genes (HLA, GABRA2, OPRM1, and Y-DNA haplogroup D-M55). Then, we evaluated and extracted significant polymorphisms that affect couple adjustment and romantic relationships. Discussion: Overall, the findings suggest that genetic and epigenetics variants play a key role in marital adjustment and romantic relationships over time.

Evaluating the neuropeptide-social cognition link in ageing: the mediating role of basic cognitive skills

The roles of oxytocin (OT) and arginine-vasopressin (AVP) as crucial modulators of social cognition and related behaviours have been extensively addressed in the literature. The involvement of these neuropeptides in social cognition in ageing, however, and a potential mediating effect of basic cognitive capacities on this link, are not well understood. To fill these research gaps, this study assessed associations of plasma OT and AVP levels with dynamic emotion identification accuracy in generally healthy older men (aged 55-95 years) and probed the underlying roles of crystallized and fluid cognition in these associations. Higher plasma OT levels were associated with lower accuracy in dynamic emotion identification, with this negative relationship fully mediated by cognition. For plasma AVP levels, in contrast, there was no association with dynamic emotion identification accuracy. Integrated within existing theoretical accounts, results from this study advance understanding of the neuropeptide-social cognition link in ageing and support basic cognitive capacities as mediators in this association. This article is part of the theme issue 'Interplays between oxytocin and other neuromodulators in shaping complex social behaviours'.

Hormonal Profile in Response to an Empathic Induction Task in Perpetrators of Intimate Partner Violence: Oxytocin/Testosterone Ratio and Social Cognition

Empathy deficits have been proposed to be an important factor for intimate partner violence (IPV). IPV perpetrators have shown a differential change in salivary oxytocin (sOXT), testosterone (sT), and cortisol (sC), following empathic and stress tasks, compared to non-violent men. However, the influence of empathic deficits in those hormones after an emotion-induction task in IPV perpetrators remains unclear. We analyzed the effects of an empathic induction task on endogenous sOXT, sT and sC levels, as well as their hormonal ratios, in IPV perpetrators (n = 12), and compared them to controls (n = 12). Additionally, we explored the predictive capacity of empathy-related functions (measured with the interpersonal reactivity index) in the hormonal responses to the task. IPV perpetrators presented lower sOXT changes and higher total sT levels than controls after the task, lower sOXT/T change and total sOXT/T levels, as well as higher total sT/C levels. Notably, for all participants, the lower the perspective taking score, the lower the total sOXT levels and sOXT changes and the higher the sT changes were. Low perspective taking also predicted smaller sOXT/T and sOXT/C changes in the empathic induction task, and higher total sT/C levels for all participants. Therefore, our results could contribute to furthering our ability to focus on new therapeutic targets, increasing the effectiveness of intervention programs and helping to reduce IPV recidivism in the medium term.

Functional Neuroimaging of Human Hypothalamus in Socioemotional Behavior: A Systematic Review

There exist extensive animal research and lesion studies in humans demonstrating a tight association between the hypothalamus and socioemotional behavior. However, human neuroimaging literature in this direction is still rather limited. In order to reexamine the functional role of this region in regulating human social behavior, we here provided a synthesis of neuroimaging studies showing hypothalamic activation during affiliative, cooperative interactions, and in relation to ticklish laughter and humor. In addition, studies reporting involvement of the hypothalamus during aggressive and antisocial interactions were also considered. Our systematic review revealed a growing number of investigations demonstrating that the evolutionary conserved hypothalamic neural circuity is involved in multiple and diverse aspects of human socioemotional behavior. On the basis of the observed heterogeneity of hypothalamus-mediated socioemotional responses, we concluded that the hypothalamus might play an extended functional role for species survival and preservation, ranging from exploratory and approaching behaviors promoting social interactions to aggressive and avoidance responses protecting and defending the established social bonds.

Salivary oxytocin after play with parents predicts behavioural problems in preschool children

BACKGROUND

Oxytocin (OXT) has attracted research interest for its potential involvement in many of the behavioural problems observed in childhood. Due to its logistical advantages, saliva is an attractive fluid to quantify neuropeptides in children. Salivary OXT has been suggested as a potential biomarker for psychopathology during childhood. However, several questions still remain about the extent to which, and under what conditions, concentrations of OXT in saliva can be reliably measured and are related to behavioural problems in preschool age children.

METHODS

Seven samples of saliva from 30 preschool children (17 girls) were collected in five different days at their homes. Three of the samples were collected by the children's parents at baseline daily routine conditions, and four of the samples were collected by researchers during two home-visits: before and after two 15-minute dyadic play sessions (one with mothers and one fathers) between each individual parent and the child. Oxytocin concentrations were quantified by Radioimmunoassay with prior extraction. Children's behavioural problems were assessed by the Caregiver-Teacher Report Form (C-TRF) questionnaire, completed by the child's' preschool teacher.

RESULTS

Salivary OXT measured in baseline samples could not predict any of the behavioural problems measured by the C-TRF. However, when measured after playing with parents salivary OXT showed a stronger pattern of negative correlations, specially with the depression and opposition scales of the C-TRF. Furthermore, salivary OXT was unlikely to be reliably measured using single sampling, but acceptable reliabilities were achieved when averaging several samples. Finally, the single measures of salivary OXT evoked after an episode of play with parents showed better reliabilities than collected at baseline.

CONCLUSION

Measurements of OXT evoked after positive affect interactions with parents seem to capture aspects of the OXT system in young children that might be relevant for understanding the role of this system in children's social behaviour.

Temporal Dynamics of Intranasal Oxytocin in Human Brain Electrophysiology

Oxytocin (OT) is a key modulator of human social cognition, popular in behavioral neuroscience. To adequately design and interpret intranasal OT (IN-OT) research, it is crucial to know for how long it affects human brain function once administered. However, this has been mostly deduced from peripheral body fluids studies, or uncommonly used dosages. We aimed to characterize IN-OT’s effects on human brain function using resting-state EEG microstates across a typical experimental session duration. Nineteen healthy males participated in a double-blind, placebo-controlled, within-subject, cross-over design of 24 IU of IN-OT in 12-min windows 15 min-to-1 h 42min after administration. We observed IN-OT effects on all microstates, across the observation span. During eyes-closed, IN-OT increased duration and contribution of A and contribution and occurrence of D, decreased duration and contribution of B and C; and increased transition probability C-to-B and C-to-D. In eyes-open, it increased A-to-C and A-to-D. As microstates A and D have been related to phonological auditory and attentional networks, respectively, we posit IN-OT may tune the brain for reception of external stimuli, particularly of social nature—tentatively supporting current neurocognitive hypotheses of OT. Moreover, we contrast our overall results against a comprehensive literature review of IN-OT time-course effects in the brain, highlighting comparability issues.

Endogenous Oxytocin Levels in Autism-A Meta-Analysis

Oxytocin (OT) circuitry plays a major role in the mediation of prosocial behavior. Individuals with autism spectrum disorder (ASD) are characterized by impairments in social interaction and communication and have been suggested to display deficiencies in central OT mechanisms. The current preregistered meta-analysis evaluated potential group differences in endogenous OT levels between individuals with ASD and neurotypical (NT) controls. We included 18 studies comprising a total of 1422 participants. We found that endogenous OT levels are lower in children with ASD as compared to NT controls (n = 1123; g = -0.60; p = 0.006), but this effect seems to disappear in adolescent (n = 152; g = -0.20; p = 0.53) and adult populations (n = 147; g = 0.27; p = 0.45). Secondly, while no significant subgroup differences were found in regard to sex, the group difference in OT levels of individuals with versus without ASD seems to be only present in the studies with male participants (n = 814; g = -0.44; p = 0.08) and not female participants (n = 192; g = 0.11; p = 0.47). More research that employs more homogeneous methods is necessary to investigate potential developmental changes in endogenous OT levels, both in typical and atypical development, and to explore the possible use of OT level measurement as a diagnostic marker of ASD.

Practitioner's review: medication for children and adolescents with autism spectrum disorder (ASD) and comorbid conditions

Alleviating the multiple problems of children with autism spectrum disorder (ASD) and its comorbid conditions presents major challenges for the affected children, parents, and therapists. Because of a complex psychopathology, structured therapy and parent training are not always sufficient, especially for those patients with intellectual disability (ID) and multiple comorbidities. Moreover, structured therapy is not available for a large number of patients, and pharmacological support is often needed, especially in those children with additional attention deficit/hyperactivity and oppositional defiant, conduct, and sleep disorders.

Bioavailability and pharmacokinetic profile of balovaptan, a selective, brain-penetrant vasopressin 1a receptor antagonist, in healthy volunteers

BACKGROUND

Balovaptan is a potent, selective vasopressin 1a receptor antagonist. The early-phase pharmacokinetics (PK) of balovaptan are reported.

RESEARCH DESIGN AND METHODS

Two Phase 1 studies (overall N = 93) assessed single- and multiple-dose balovaptan PK in healthy adults. One (N = 16) assessed absolute oral bioavailability (10 mg or 50 mg) vs a [¹³C]-balovaptan microdose. The other (N = 77) explored single- (0.5-76 mg) and multiple-dose (14 days; 12-52 mg/day) - randomized 6:2 balovaptan:placebo per dose - PK, dose proportionality, and the effect of food on single-dose (32 mg) C_max and AUC_inf.

RESULTS

Absolute balovaptan bioavailability was high (103-116%). Steady-state (Day 14) balovaptan PK was approximately dose proportional with a half-life of 45-47 hours, but single-dose C_max increased more than dose proportionally and half-life was inversely dose-proportional - a discordance partially attributable to a dose-and-time-dependent volume of distribution. Accumulation (Day 1-Day 14) was inversely dose-proportional (~3.5 [12 mg] to ~1.8 [52 mg]). There was no relevant effect of a high-fat meal on single-dose balovaptan exposure. There were no safety signals: 2/93 subjects discontinued for adverse events.

CONCLUSIONS

Balovaptan was well tolerated at single (≤76 mg) and multiple (≤52 mg/day) doses, with a PK profile supportive of once-daily administration without food restrictions.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03764449; NCT01418963.

The link between oxytocin plasma levels and observed communication behaviors during sexual and nonsexual couple discussions: An exploratory study

The role of oxytocin (OT) in close relationships is complex, as both positive and negative associations have been found between OT and relationship processes. Also, with most research focusing on the effects of exogenous OT administration on communication and couple behaviors, our knowledge about the association between endogenous OT and couple dynamics remains limited. This study is the first to assess the link between peripheral OT levels and observed communication behaviors during sexual and nonsexual conflict discussions in romantic relationships. A sample of 126 young, heterosexual couples (Mean age = 23.3, SD = 2.4; average relationship duration = 1.9 years, SD = 0.9) participated in videotaped sexual and nonsexual couple conflict discussions of 7 min each. Communication behaviors were coded using an adaptation of the Specific Affect Coding System (SPAFF) and the System for Coding Interactions and Family Functioning (SCIFF). Blood samples were collected prior to the couple discussions, during a separate lab visit, and OT plasma levels were determined using enzyme-linked immunosorbent assays (ELISA). Plasma OT levels were positively associated with validating behaviors during sexual discussions in both women (r = +.24, p = .008) and men (r = +.18, p = .052). No significant associations were found between OT levels and validating behaviors during nonsexual discussions and between OT and affectionate and negative behaviors during either sexual or nonsexual discussions. Analyses revealed significant associations between OT levels and one's own validating behaviors during sexual discussions (b = 47.82, t(201.16) = 3.81, p < .001) and one's partner's (b = 32.12, t(216.35) = 2.62, p = .009). The results highlight the biobehavioral aspects of couples' sexual communication and may contribute to a better understanding of the processes involved in individual and relational well-being. This study is the first to report an association between peripheral OT levels and validating behaviors during sexual communication, indicating neurophysiological involvement in dyadic sexual communication patterns.

Neuroendocrine Factors in Melanoma Pathogenesis

Simple Summary

Melanoma is a very aggressive and fatal malignant tumor. While curable if diagnosed in its early stages, advanced melanoma, despite the complex therapeutic approaches, is associated with one of the highest mortality rates. Hence, more and more studies have focused on mechanisms that may contribute to melanoma development and progression. Various studies suggest a role played by neuroendocrine factors which can act directly on tumor cells, modulating their proliferation and metastasis capability, or indirectly through immune or inflammatory processes that impact disease progression. However, there are still multiple areas to explore and numerous unknown features to uncover. A detailed exploration of the mechanisms by which neuroendocrine factors can influence the clinical course of the disease could open up new areas of biomedical research and may lead to the development of new therapeutic approaches in melanoma.

Abstract

Melanoma is one of the most aggressive skin cancers with a sharp rise in incidence in the last decades, especially in young people. Recognized as a significant public health issue, melanoma is studied with increasing interest as new discoveries in molecular signaling and receptor modulation unlock innovative treatment options. Stress exposure is recognized as an important component in the immune-inflammatory interplay that can alter the progression of melanoma by regulating the release of neuroendocrine factors. Various neurotransmitters, such as catecholamines, glutamate, serotonin, or cannabinoids have also been assessed in experimental studies for their involvement in the biology of melanoma. Alpha-MSH and other neurohormones, as well as neuropeptides including substance P, CGRP, enkephalin, beta-endorphin, and even cellular and molecular agents (mast cells and nitric oxide, respectively), have all been implicated as potential factors in the development, growth, invasion, and dissemination of melanoma in a variety of in vitro and in vivo studies. In this review, we provide an overview of current evidence regarding the intricate effects of neuroendocrine factors in melanoma, including data reported in recent clinical trials, exploring the mechanisms involved, signaling pathways, and the recorded range of effects.

Oxytocin Pathway Gene (CD38, OXTR) Variants Are Not Related to Psychosocial Characteristics Defined by Strengths and Difficulties Questionnaire in Adolescents: A Field School-Based Study

Background: CD38 is a transmembrane glycoprotein that regulates oxytocin (OT) production and influences social interactions. The oxytocin receptor (OXTR) has been studied intensively regarding its association with human psychosocial functions. Many studies have demonstrated a link between CD38 rs3796863 and OXTR rs53576 polymorphic regions and psychosocial characteristics as well as various psychiatric disorders in adolescents. Some studies, however, have reported null findings. Methods: The Strengths and Difficulties Questionnaire (SDQ) is a brief psychopathologic screening tool recommended for detecting psychosocial problems and psychiatric disorders in adolescents. The current field school-based study, conducted among urban Siberian adolescents (n = 298 aged 12-18), explored the SDQ scales in relation to polymorphisms of the CD38 and the OXTR genes (rs3796863 and rs53576, respectively). Results: None of the studied genotypes were associated with the SDQ results for the complete sample with presumed statistical power as 0.80 to detect a medium-size effect (Cramer's V = 0.3) at α = 0.0083. Post-hoc analysis in subgroups showed that OT pathway high activity may cause some negative consequences, such as emotional instability in older (aged 15-18) adolescent boys who are carriers of the rs53576 GG variant. Conclusion: Variations at the CD38 rs3796863 and OXTR rs53576 loci were not associated with psychosocial characteristics of adolescents assessed with the SDQ. In studies with a similar design, we recommend replication with larger samples and greater power to detect small effects, especially in age-sex subgroups of adolescents.

Transcutaneous Electrical Acupoint Stimulation in Early Life Changes Synaptic Plasticity and Improves Symptoms in a Valproic Acid-Induced Rat Model of Autism

Autism spectrum disorder (ASD) is a developmental disorder characterized by social behavior deficit in childhood without satisfactory medical intervention. Transcutaneous electrical acupoint stimulation (TEAS) is a noninvasive technique derived from acupuncture and has been shown to have similar therapeutic effects in many diseases. Valproic acid- (VPA-) induced ASD is a known model of ASD in rats. The therapeutic efficacy of TEAS was evaluated in the VPA model of ASD in the present study. The offspring of a VPA-treated rat received TEAS in the early life stage followed by a series of examinations conducted in their adolescence. The results show that following TEAS treatment in early life, the social and cognitive ability in adolescence of the offspring of a VPA rat were significantly improved. In addition, the abnormal pain threshold was significantly corrected. Additional studies demonstrated that the dendritic spine density of the primary sensory cortex was decreased with Golgi staining. Results of the transcriptomic study showed that expression of some transcription factors such as the neurotrophic factor were downregulated in the hypothalamus of the VPA model of ASD. The reduced gene expression was reversed following TEAS. These results suggest that TEAS in the early life stage may mitigate disorders of social and recognition ability and normalize the pain threshold of the ASD rat model. The mechanism involved may be related to improvement of synaptic plasticity.

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.

Mechanisms for the Approach/Avoidance Decision Applied to Autism

As a neurodevelopmental disorder with serious lifelong consequences, autism has received considerable attention from neuroscientists and geneticists. We present a hypothesis of mechanisms plausibly affected during brain development in autism, based on neural pathways that are associated with social behavior and connect the prefrontal cortex (PFC) to the basal ganglia (BG). We consider failure of social approach in autism as a special case of imbalance in the fundamental dichotomy between behavioral approach and avoidance. Differential combinations of genes mutated, differences in the timing of their impact during development, and graded degrees of hormonal influences may help explain the heterogeneity in symptomatology in autism and predominance in boys.

Noise during mouthbrooding impairs maternal care behaviors and juvenile development and alters brain transcriptomes in the African cichlid fish Astatotilapia burtoni

Anthropogenic noise has increased underwater ambient sound levels in the range in which most fishes detect and produce acoustic signals. Although the impacts of increased background noise on fish development have been studied in a variety of species, there is a paucity of information on how noise affects parental care. Mouthbrooding is an energetically costly form of parental care in which the brooding fish carries developing larvae in the buccal cavity for the duration of development. In the African cichlid Astatotilapia burtoni, females carry their brood for ~2 weeks during which time they do not eat. To test the hypothesis that increased background noise impacts maternal care behaviors and brood development, we exposed brooding females to a 3-h period of excess noise (~140 dB) played through an underwater speaker. Over half of noise-exposed brooding females cannibalized or pre-maturely released their brood, but 90% of control females exhibited normal brooding behaviors. RNA-seq analysis revealed that transcripts related to feeding and parental care were differentially expressed in the brains of noise-exposed females. Juveniles that were exposed to noise during their brood period within the mother's mouth had lower body condition factors, higher mortality and altered head transcriptomes compared with control broods. Furthermore, onset of adult-typical coloration and behaviors was delayed compared with control fish. Together, these data indicate that noise has severe impacts on reproductive fitness in mouthbrooding females. Our results, combined with past studies, indicate that parental care stages are extremely susceptible to noise-induced perturbations with detrimental effects on species persistence.

Morphofunctional Alterations of the Hypothalamus and Social Behavior in Autism Spectrum Disorders

An accumulating body of evidence indicates a tight relationship between the endocrine system and abnormal social behavior. Two evolutionarily conserved hypothalamic peptides, oxytocin and arginine-vasopressin, because of their extensively documented function in supporting and regulating affiliative and socio-emotional responses, have attracted great interest for their critical implications for autism spectrum disorders (ASD). A large number of controlled trials demonstrated that exogenous oxytocin or arginine-vasopressin administration can mitigate social behavior impairment in ASD. Furthermore, there exists long-standing evidence of severe socioemotional dysfunctions after hypothalamic lesions in animals and humans. However, despite the major role of the hypothalamus for the synthesis and release of oxytocin and vasopressin, and the evident hypothalamic implication in affiliative behavior in animals and humans, a rather small number of neuroimaging studies showed an association between this region and socioemotional responses in ASD. This review aims to provide a critical synthesis of evidences linking alterations of the hypothalamus with impaired social cognition and behavior in ASD by integrating results of both anatomical and functional studies in individuals with ASD as well as in healthy carriers of oxytocin receptor (OXTR) genetic risk variant for ASD. Current findings, although limited, indicate that morphofunctional anomalies are implicated in the pathophysiology of ASD and call for further investigations aiming to elucidate anatomical and functional properties of hypothalamic nuclei underlying atypical socioemotional behavior in ASD.

Emerging pharmacological therapies in fragile X syndrome and autism

PURPOSE OF REVIEW

Research on the pathophysiology of syndromic autism spectrum disorder (ASD) has contributed to the uncovering of mechanisms in nonsyndromic ASD. The current review aims to compare recent progress in therapeutics development for ASD with those for fragile X syndrome (FXS), the most frequent monogenic form of ASD.

RECENT FINDINGS

Although candidates such as oxytocin, vasopressin, and cannabinoids are being tested as novel therapeutics, it remains difficult to focus on a specific molecular target of drug development for ASD core symptoms. As the pathophysiology of FXS has been well described as having a causal gene, fragile X mental retardation-1, development of therapeutic agents for FXS is focused on specific molecular targets, such as metabotropic glutamate receptor 5 and GABAB receptor.

SUMMARY

There is a large unmet medical need in ASD, a heterogeneous and clinically defined behavioral syndrome, owing to its high prevalence in the general population, lifelong cognitive and behavioral deficits, and no established treatment of ASD core symptoms, such as deficits in social communication and restrictive repetitive behaviors. The molecular pathogenesis of nonsyndromic ASD is largely undefined. Lessons from initial attempts at targeted treatment development in FXS, and new designs resulting from these lessons, will inform trials in nonsyndromic ASD for development of therapeutics for its core symptoms.

Effects of Stroking on Salivary Oxytocin and Cortisol in Guide Dogs: Preliminary Results

This pilot study aimed at investigating how salivary oxytocin levels are affected by human interaction and isolation in eight guide dogs (six Labrador retrievers and two golden retrievers; four males and four females, 21.87 ± 1.36 months old) just before assignment to the blind person. Each dog engaged, at one-week intervals, in a positive (5 min of affiliative interaction with their trainer) and a negative (5 min of isolation) condition. Saliva samples used for Enzyme Immunoassay (EIA) quantification of salivary oxytocin were collected before and immediately after both experimental conditions. In order to assess potential hypothalamic pituitary adrenal (HPA) axis activation that could have affected oxytocin levels, saliva samples were collected 15 min after both experimental conditions for EIA quantification of salivary cortisol and a behavioral assessment was performed during the negative condition. The results were compared using the Wilcoxon test (p < 0.05). Oxytocin concentrations showed a statistically significant increase after the positive interaction (p = 0.036) and no difference after the negative one (p = 0.779). Moreover, no difference (p = 0.263) was found between the cortisol concentrations after each experimental condition and no signs of distress were observed during the isolation phase. These preliminary findings support the hypothesis that stroking dogs has positive effects on their emotional state independently of hypothalamic pituitary adrenal axis activation.

Determinants of Ageism against Older Adults: A Systematic Review

Ageism is a widespread phenomenon and constitutes a significant threat to older people's well-being. Identifying the factors contributing to ageism is critical to inform policies that minimise its societal impact. In this systematic review, we gathered and summarised empirical studies exploring the key determinants of ageism against older people for a period of over forty years (1970-2017). A comprehensive search using fourteen databases identified all published records related to the umbrella concept of "ageism". Reviewers independently screened the final pool to identify all papers focusing on determinants, according to a predefined list of inclusion and exclusion criteria. All relevant information was extracted and summarised following a narrative synthesis approach. A total of 199 papers were included in this review. We identified a total of 14 determinants as robustly associated with ageism. Of these, 13 have an effect on other-directed ageism, and one on self-directed ageism. The quality of contact with older people and the positive or negative presentation of older people to others emerged as the most robust determinants of other-directed ageism; self-directed ageism is mostly determined by older adults' health status. Given the correlational nature of most studies included in this review, inferences on causality should be made cautiously.

One Single Nucleotide Polymorphism of the TRPM2 Channel Gene Identified as a Risk Factor in Bipolar Disorder Associates with Autism Spectrum Disorder in a Japanese Population

The transient receptor potential melastatin 2 (TRPM2) is a non-specific cation channel, resulting in Ca²⁺ influx at warm temperatures from 34 °C to 47 °C, thus including the body temperature range in mammals. TRPM2 channels are activated by β-NAD⁺, ADP-ribose (ADPR), cyclic ADPR, and 2′-deoxyadenosine 5′-diphosphoribose. It has been shown that TRPM2 cation channels and CD38, a type II or type III transmembrane protein with ADP-ribosyl cyclase activity, simultaneously play a role in heat-sensitive and NAD⁺ metabolite-dependent intracellular free Ca²⁺ concentration increases in hypothalamic oxytocinergic neurons. Subsequently, oxytocin (OT) is released to the brain. Impairment of OT release may induce social amnesia, one of the core symptoms of autism spectrum disorder (ASD). The risk of single nucleotide polymorphisms (SNPs) and variants of TRPM2 have been reported in bipolar disorder, but not in ASD. Therefore, it is reasonable to examine whether SNPs or haplotypes in TRPM2 are associated with ASD. Here, we report a case-control study with 147 ASD patients and 150 unselected volunteers at Kanazawa University Hospital in Japan. The sequence-specific primer-polymerase chain reaction method together with fluorescence correlation spectroscopy was applied. Of 14 SNPs examined, one SNP (rs933151) displayed a significant p-value (OR = 0.1798, 95% CI = 0.039, 0.83; Fisher’s exact test; p = 0.0196). The present research data suggest that rs93315, identified as a risk factor for bipolar disorder, is a possible association factor for ASD.

[Oxitocin is a hormone of trust and emotional attachment: the influence on behavior of children and adolescents]

This review presents current data on the mechanisms of production and reception of oxytocin and its effect on the socio-emotional aspects of behavior in different age periods of childhood and adolescence. The main hormonal role of oxytocin is to regulate the process of carrying a fetus, childbirth and lactation, as well as the establishment of social connections from the infancy period (connection with parents with a child) throughout childhood to adolescence and adult periods of life. Its central action takes the most important part in cognitive, emotional and behavioral processes. In addition, oxytocin plays a role in the regulation of food and sexual behavior, in the mechanisms of visceral hypersensitivity and pain perception. The analysis of publications covering the most important role of oxytocin in the formation of the emotional interaction between parents and children in different age periods: infancy, preschool and adolescence was carried out. A brief analysis of genetically determined features of the production and reception of oxytocin and their role in the regulation of behavioral responses is presented. In addition, the review briefly highlights aspects of the likely involvement of oxytocin in the mechanisms of formation of certain psychopathological conditions in children and adolescents.

The Influence of an Attachment-Related Stimulus on Oxytocin Reactivity in Poly-Drug Users Undergoing Maintenance Therapy Compared to Healthy Controls

BACKGROUND

Substance use disorders (SUDs) have been described as a dysfunctional way to compensate for deficiencies in that person's underlying attachment system. Furthermore, the neuropeptide oxytocin (OT), which is a critical component of the neurobiology of the attachment system, has been shown to effectively reduce addictive behavior and therefore has been discussed as a potential medication in SUD treatment. This study investigates variation in peripheral OT plasma levels as a function of exposure to an attachment-related stimulus in SUD patients compared to healthy controls (HCs).

METHODS

A total sample of 48 men, 24 inpatients in maintenance treatment who were diagnosed with poly-drug use disorder (PUD) and 24 HC, was investigated. A 15-min exposure to the Adult Attachment Projective Picture System (AAP) was used as an attachment-related stimulus and coded for attachment status. Blood samples before and after the AAP-assessment were taken and assayed for OT levels. Variation in baselines level of OT was examined in relation to the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST), the Adult Attachment-Scale (AAS), and the Brief Symptom Inventory (BSI).

RESULTS

Following the AAP stimulus controls showed no significant difference in OT levels elevation from baseline compared to the PUD group's OT levels. Furthermore, in the PUD group only OT-baseline-levels may be negatively associated with the AAS subscale "Comfort with Closeness" and "Anxiety" and lifetime substance use.

DISCUSSION

Our results suggest that peripheral OT levels in poly-drug users undergoing maintenance treatment are not significantly different in responsiveness to an attachment related stimulus compared to HC. With regard to non-significant tendencies observed in this study which hint toward decreased OT-reactivity in the PUD group, further research is needed to explore this hypothesis with increased statistical power.

Interaction between polymorphisms of the oxytocinergic system genes and emotion perception in inpatients with anorexia nervosa

OBJECTIVE

The empirical literature describes the role of the oxytocinergic system in emotion perception (EP). Variants in the oxytocin (OXT) and oxytocin receptor genes have been associated with mental disorders, including anorexia nervosa (AN), that are characterized by difficulties in socioemotional functioning. Our study aimed to examine whether variability within the genes related to OXT pathways may play a role in facial EP in inpatients with AN.

METHOD

Single nucleotide polymorphisms (SNPs) of the following genes: oxytocin receptor (rs2254298, rs53576), OXT (rs6133010), OXT-arginine-vasopressin (rs2740204), CD38 (rs6449197, rs3796863), and human leucyl/cystinylaminopeptidase (rs4869317) were genotyped in 60 AN female inpatients and 60 healthy control females (HCs). Associations between genetic polymorphisms and EP as well as clinical symptoms were examined.

RESULTS

The AN group showed decreased EP abilities compared with HCs. SNPs of rs2740204, rs6133010, and rs53576 were associated with differences in EP in women with AN and in HCs. The SNP of rs4869317 was associated with the level of eating disorders symptoms in HCs.

CONCLUSIONS

The OXT system may be involved in EP difficulties in AN. SNPs within genes related to OXT pathways may influence EP abilities. The leucyl/cystinylaminopeptidase rs4869317 SNP may be involved in the development of eating disorders psychopathology.

Social Interaction Improved by Oxytocin in the Subclass of Autism with Comorbid Intellectual Disabilities

Approximately half of all autism spectrum disorder (ASD) individuals suffer from comorbid intellectual disabilities. Furthermore, the prevalence of epilepsy has been estimated to be 46% of patients with low intelligence quotient. It is important to investigate the therapeutic benefits and adverse effects of any recently developed drugs for this proportion of individuals with the so-called Kanner type of ASD. Therefore, we investigated the therapeutic and/or adverse effects of intranasal oxytocin (OT) administration, especially in adolescents and adults with ASD and comorbid intellectual disability and epilepsy, with regard to core symptoms of social deficits. We have already reported three randomized placebo-controlled trials (RCTs). However, we revisit results in our pilot studies from the view of comorbidity. Most of the intellectually disabled participants were found to be feasible participants of the RCT. We observed significantly more events regarded as reciprocal social interaction in the OT group compared with the placebo group. In the trial, no or little differences in adverse events were found between the OT and placebo arms, as found in some other reports. However, seizures were induced in three participants with medical history of epilepsy during or after OT treatment. In conclusion, we stress that behavioral changes in ASD patients with intellectual disabilities could be recognized not by the conventional measurements of ASD symptoms but by detailed evaluation of social interactions arising in daily-life situations.

A Longitudinal Multilevel Study of the "Social" Genotype and Diversity of the Phenotype

Sociability and social domain-related behaviors have been associated with better well-being and endogenous oxytocin levels. Inspection of the literature, however, reveals that the effects between sociability and health outcomes, or between sociability and genotype, are often weak or inconsistent. In the field of personality psychology, the social phenotype is often measured by error-prone assessments based on different theoretical frameworks, which can partly explain the inconsistency of the previous findings. In this study, we evaluated the generalizability of “sociability” measures by partitioning the population variance in adulthood sociability using five indicators from three personality inventories and assessed in two to four follow-ups over a 15-year period (n = 1,573 participants, 28,323 person-observations; age range 20–50 years). Furthermore, we tested whether this variance partition would shed more light to the inconsistencies surrounding the “social” genotype, by using four genetic variants (rs1042778, rs2254298, rs53576, rs3796863) previously associated with a wide range of human social functions. Based on our results, trait (between-individual) variance explained 23% of the variance in overall sociability, differences between sociability indicators explained 41%, state (within-individual) variance explained 5% and measurement errors explained 32%. The genotype was associated only with the sociability indicator variance, suggesting it has specific effects on sentimentality and emotional sharing instead of reflecting general sociability.