# Parasympathetic nervous activity and CTRA gene expression among healthy young adults in Japan

## TL;DR

This study shows that higher parasympathetic nervous system activity is linked to reduced inflammation in Japanese young adults, similar to findings in Western populations.

## Contribution

The study confirms the generalizability of PNS-CTRA relationships in a Japanese population, extending prior findings from Western samples.

## Key findings

- Higher heart rate variability (HRV) is associated with lower CTRA gene expression in Japanese young adults.
- Genome-wide analysis shows HRV links to up-regulated interferon response and down-regulated NF-κB activity.
- Neuro-immune regulation of CTRA appears consistent between East Asian and Western populations.

## Abstract

Previous research suggests that parasympathetic nervous system (PNS) activity may inhibit the leukocyte Conserved Transcriptional Response to Adversity (CTRA) which has been observed in individuals exposed to prolonged stressors like loneliness, social isolation, and bereavement. Previous PNS-CTRA studies have focused on Western populations, raising questions about the generalizability of these findings across different cultural and ethnic backgrounds. This study examined the relationship between PNS activity (as indexed by heart rate variability; HRV) and CTRA gene expression in young, healthy adults in Japan (n = 26; Mean age = 26; 34.6 % female). In analyses that controlled for demographic and behavioral covariates (including age, sex, ethnicity, smoking, alcohol, and BMI), results showed a significant inverse relationship between HRV and CTRA gene expression (i.e., lower expression of pro-inflammatory genes and elevated expression of Type I interferon response genes). Convergent validation analyses of genome-wide transcription factor activity linked HRV to up-regulation of Interferon Response Factors and down-regulation of NF-κB. These results parallel previous findings from Western samples, confirming that PNS neuro-immune regulation generalizes to an population based in Japan, as part of broader East Asian region and identifying HRV as a useful index for optimizing immune health in diverse populations.

•Higher PNS is linked to reduced inflammation including CTRA in western populations.•Race and ethnicity may modify the relation between PNS and inflammatory biomarkers.•Higher PNS was also related to lower CTRA gene expression in Japanese young adults.•Neuro-immune regulation of the CTRA appeared similar in Asian vs Western populations.

Higher PNS is linked to reduced inflammation including CTRA in western populations.

Race and ethnicity may modify the relation between PNS and inflammatory biomarkers.

Higher PNS was also related to lower CTRA gene expression in Japanese young adults.

Neuro-immune regulation of the CTRA appeared similar in Asian vs Western populations.