Effects of intranasal oxytocin and positive couple interaction on immune factors in skin wounds

Oxytocin impairs wound-healing during social isolation but not social living

Social isolation hampers immune system function, and the biological mechanisms driving this effect remain understudied. We hypothesized that oxytocin (OT), a key neuropeptide involved in social cognition, is a critical mediator of social context on immune function. In the California mouse (Peromyscus californicus), we examined how female and male immune function is influenced by (1) social isolation from same-sex peers, (2) social peer affiliation, and (3) exogenous OT. We evaluated immune function through wound size progression following a skin biopsy and proinflammatory cytokines in the wound fluid. Unexpectedly, social isolation alone did not influence wound healing, but isolation + OT increased wound size in a dose dependent manner. Wound size progression interacted with sex and OT in socially-housed mice, suggesting that OT increases inflammation in females, while decreasing inflammation in males in a social context-dependent manner. Inflammatory biomarker interleukin-6 (IL-6) mRNA expression correlated with wound size overall, supporting wound healing as an index of inflammatory response. However, isolation + OT mice did not have higher levels of IL-6, suggesting that the mechanism through which isolation + OT influences wound size is not through IL-6 activity. Behaviorally, higher levels of affiliation were negatively associated with wound size, and this effect was diminished by OT treatment. Our results highlight that the anti-inflammatory effects of OT are likely highly dependent on social context.

Minimal couple intervention to improve psychobiological stress resilience

OBJECTIVE

This study aimed at evaluating the effects of a minimal couple intervention focusing on positive aspects within the relationship (instructed partnership appreciation task; PAT) in daily life. We hypothesized a stress-buffering effect of this intervention on perceived stress, salivary cortisol and alpha-amylase.

METHODS

N = 40 couples were randomly assigned to either PAT or a no PAT (nPAT) condition. Self-reports and saliva samples were assessed six times per day on five consecutive days. To account for couple interdependencies, multilevel modelling (MLM) approaches were used to test the effects of (a) group assignment (PAT vs. nPAT) and (b) practicing the PAT in everyday life (PAT group only).

RESULTS

Overall perceived stress was lower for women in the PAT group as compared with women in the nPAT group (b = -.380, p = .0098). Within the PAT group, daily positive interaction (PAT) significantly reduced cortisol (b = -.127, p = .02) and alpha amylase (b = -.122, p = .037). Sex-specific analyses of within-participants effects in daily life indicate that these results were driven by the men in the sample: Practicing the PAT led to a decrease in perceived stress (b = -.271, p = 001) and sCort (b = -.226, p = .006) in men, but not in women (all p > .05).

CONCLUSIONS

The findings suggest that a minimal couple intervention can improve individual health-related outcomes in a sex-specific manner, and that effects depend on actually practicing the positive exchange in daily life.

TRIAL REGISTRATION

The analysis of the present study is based on a sub-sample (placebo group) of a larger neuropharmacological intervention and longitudinal trial 'Oxytocin, Couple Interaction and Wound Healing' (clinicaltrials.gov, identifier NCT01594775).

Hormonal synchrony in older couples' everyday life: The role of situational stressors and buffers

Synchrony in physiology in romantic couples has been suggested to be a result of joint interaction and co-regulation of stress and affect. However, it is subject of debate whether synchrony in endocrine levels - especially in oxytocin - is generally beneficial or if a reciprocal transmission of stress may even be stress-increasing. The aim of this study was to investigate hormonal synchrony in older couples in relation to situational mindfulness, relationship conflict (quarreling), as well as situational resilience and subjective stress levels. A total of N = 26 individuals (i.e., N = 13 couples) aged between 52 and 75 years provided saliva samples and self-report measures 12 times over the course of 2 days (312 measures in total). Superior to randomly scrambled dyads, multilevel models predicted cortisol, alpha-amylase, and oxytocin levels from one partner for the other. Synchrony was higher at times of high levels of quarreling but mitigated in moments of high mindfulness. Moreover, oxytocin synchrony was reduced in couples exerting higher average levels of stress. We interpret this finding as buffering personal factors to protect against the transmission of dyadic stress. To draw implications for clinical interventions to promote these factors and given the preliminary character of the sample and the effects, future studies need to systematically expand this field of research and application.

Oxytocin-induced increases in cytokines and clinical effect on the core social features of autism: Analyses of RCT datasets

Although oxytocin may provide a novel therapeutics for the core features of autism spectrum disorder (ASD), previous results regarding the efficacy of repeated or higher dose oxytocin are controversial, and the underlying mechanisms remain unclear. The current study is aimed to clarify whether repeated oxytocin alter plasma cytokine levels in relation to clinical changes of autism social core feature. Here we analyzed cytokine concentrations using comprehensive proteomics of plasmas of 207 adult males with high-functioning ASD collected from two independent multi-center large-scale randomized controlled trials (RCTs): Testing effects of 4-week intranasal administrations of TTA-121 (A novel oxytocin spray with enhanced bioavailability: 3U, 6U, 10U, or 20U/day) and placebo in the crossover discovery RCT; 48U/day Syntocinon or placebo in the parallel-group verification RCT. Among the successfully quantified 17 cytokines, 4 weeks TTA-121 6U (the peak dose for clinical effects) significantly elevated IL-7 (9.74, 95 % confidence interval [CI] 3.59 to 15.90, False discovery rate corrected P (PFDR) < 0.001), IL-9 (56.64, 20.46 to 92.82, PFDR < 0.001) and MIP-1b (18.27, 4.96 to 31.57, PFDR < 0.001) compared with placebo. Inverted U-shape dose-response relationships peaking at TTA-121 6U were consistently observed for all these cytokines (IL-7: P < 0.001; IL-9: P < 0.001; MIP-1b: P = 0.002). Increased IL-7 and IL-9 in participants with ASD after 4 weeks TTA-121 6U administration compared with placebo was verified in the confirmatory analyses in the dataset before crossover (PFDR < 0.001). Furthermore, the changes in all these cytokines during 4 weeks of TTA-121 10U administration revealed associations with changes in reciprocity score, the original primary outcome, observed during the same period (IL-7: Coefficient = -0.05, -0.10 to 0.003, P = 0.067; IL-9: -0.01, -0.02 to -0.003, P = 0.005; MIP-1b: -0.02, -0.04 to -0.007, P = 0.005). These findings provide the first evidence for a role of interaction between oxytocin and neuroinflammation in the change of ASD core social features, and support the potential role of this interaction as a novel therapeutic seed. Trial registration: UMIN000015264, NCT03466671/UMIN000031412.

Effects of exogenous oxytocin and estradiol on resting-state functional connectivity in women and men

Possible interactions of the neuropeptide oxytocin and the sex hormone estradiol may contribute to previously observed sex-specific effects of oxytocin on resting-state functional connectivity (rsFC) of the amygdala and hippocampus. Therefore, we used a placebo-controlled, randomized, parallel-group functional magnetic resonance imaging study design and measured amygdala and hippocampus rsFC in healthy men (n = 116) and free-cycling women (n = 111), who received estradiol gel (2 mg) or placebo before the intranasal administration of oxytocin (24 IU) or placebo. Our results reveal significant interaction effects of sex and treatments on rsFC of the amygdala and hippocampus in a seed-to-voxel analysis. In men, both oxytocin and estradiol significantly decreased rsFC between the left amygdala and the right and left lingual gyrus, the right calcarine fissure, and the right superior parietal gyrus compared to placebo, while the combined treatment produced a significant increase in rsFC. In women, the single treatments significantly increased the rsFC between the right hippocampus and the left anterior cingulate gyrus, whereas the combined treatment had the opposite effect. Collectively, our study indicates that exogenous oxytocin and estradiol have different region-specific effects on rsFC in women and men and that the combined treatment may produce antagonistic effects.