Respiratory Sinus Arrhythmia as a Physiological Resilience Marker for Children's Health

Family cohesion moderates the inverted U-shaped curve between resting RSA and children's empathy

Resting respiratory sinus arrhythmia (RSA) and family cohesion may jointly influence children's empathy. Resting RSA has been found to exhibit an inverted U-shaped relation with empathy, and family cohesion is a psychosocial correlate of children's empathy that may moderate this relation. The present study recruited 182 first-grade children as participants (87 girls, Mage = 7.02, SDage = 0.36). Parents completed questionnaires to assess family cohesion and children's empathy. The SOMNOtouch RESP device was utilized to collect resting electrocardiogram data and calculate resting RSA. The results showed that family cohesion significantly moderated the inverted U-shaped curve between resting RSA and children's empathy. High family cohesion served as a protective factor in mitigating the negative impact of high resting RSA on empathy but could not buffer the negative effect of extremely low resting RSA on empathy among children. The findings suggest a role for high family cohesion in promoting empathy in children with moderate to high resting RSA.

Interpersonal stressors predicting inflammation in adolescents: Moderation by emotion regulation and heart rate variability?

This study assessed interpersonal stressors (peer adversity and parental rejection) as predictors of adolescents' circulating inflammatory markers, while examining emotion regulation and parasympathetic nervous system activity (at rest, reactivity, and recovery) as potential protective moderators. Data were collected in a Belgian cohort of adolescents in 2017 (n=185, 51.4 % boys, 10-18 y) and 2018 (n=98), and included serum inflammatory markers (CRP, TNFα, IFNγ, IL-6, IL-8 and IL-10), peer adversity, parental rejection, emotion regulation and heart rate variability (RMSSD-HRV, at rest and in 2018 also in response to a Trier Social Stress Test). Contrary to the hypothesis, interpersonal stressors were negatively related to TNFα (in 2017 and 2018), IFNγ (in 2017 and longitudinally) and IL-6 (in 2018). In 23 % of the tested associations, HRV at rest was a significant moderator: the negative stressor-inflammation associations were present only among adolescents with low HRV resting values. No significant moderation by HRV reactivity or recovery was detected. After correction for multiple testing, all above-mentioned significant findings disappeared. These unexpected findings may suggest that the positive association between stress exposure and circulating markers of inflammation is not yet detectable in adolescence and perhaps becomes evident only later in life.

The Interplay of Peer Victimization and Parasympathetic Nervous System Activity on Acute Inflammatory Stress Responses in Adolescence

This study examined the extent to which adolescent peer victimization predicted acute inflammatory responses to stress, and whether both resting parasympathetic nervous system (PNS) activity and PNS stress reactivity moderated this association. 83 adolescents (Mage = 14.89, SDage = 0.52, 48% female) reported their history of peer victimization and were exposed to a standardized social stress task before and after which dried blood spot samples were collected to assay inflammatory markers. Inflammatory responses to the stress task were assessed with a latent inflammatory change factor using the cytokines interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α). PNS functioning, indexed by high-frequency heart rate variability, was measured at rest and during the stressor. Contrary to hypotheses, analyses revealed no direct relation between peer victimization and acute inflammatory responses, and resting PNS activity did not moderate this association. However, peer victimization predicted stronger inflammatory responses among adolescents with weaker PNS reactivity to the stress task (b = 0.63, p = .02). This association was not observed among adolescents with stronger PNS reactivity, for whom a negative but non-significant trend was found. Weaker PNS reactivity may thus indicate victimized adolescents' vulnerability for acute inflammatory responses, whereas stronger PNS reactivity may indicate adolescents' resilience to a social stressor.

Associations of air pollution with peripheral inflammation and cardiac autonomic physiology in children

Climate change-related disasters have drawn increased attention to the impact of air pollution on health. 122 children ages 9-11 years old, M(SD) = 9.91(.56), participated. Levels of particulate matter (PM2.5) near participants' homes were obtained from the Environmental Protection Agency. Cytokines were assayed from 100 child serum samples: IL-6, IL-8, IL-10, and TNFα. Autonomic physiology was indexed by pre-ejection period (PEP), respiratory sinus arrhythmia (RSA), cardiac autonomic regulation (CAR), and cardiac autonomic balance (CAB). IL-6 was positively related to daily PM2.5 (r = .26, p = .009). IL-8 was negatively associated with monthly PM2.5 (r = -.23, p = .02). PEP was positively related to daily (r = .29, p = .001) and monthly PM2.5 (r = .18, p = .044). CAR was negatively associated with daily PM2.5 (r = -.29, p = .001). IL-10, TNFα, RSA, and CAB were not associated with PM2.5. Air pollution may increase risk of inflammation in children.

The cholinergic anti-inflammatory pathway in humans: State-of-the-art review and future directions

The parasympathetic nervous system modulates inflammation through efferent vagus nerve signaling. Tracey (2002) termed this process as the cholinergic anti-inflammatory pathway (CAP). Interest in the potential practical use of this immune-modulatory process is increasing alongside increasing appreciation for the role of systemic inflammation in the etiology of somatic and psychological disease. A diverse literature exists providing expansive correlational evidence and some preliminary experimental evidence of the CAP in humans. However, so far this literature has not been well integrated and critically evaluated. This review describes the current state-of-the-art of research into vagus nerve driven parasympathetic control of inflammation in humans. Substantial limitations and gaps in the literature are identified, and promising directions for future research are highlighted.