Demographic correlates of inflammatory and antiviral gene expression in the study of Midlife in the United States (MIDUS)

IBS stress reactivity phenotype is associated with blood transcriptome profiles and microstructural and functional brain changes

Background & Aims

Clinical evidence suggests significant interindividual differences in stress reactivity (SR), but biological mechanisms and therapeutic implications of these differences are poorly understood. We aimed to identify the biological basis of increased SR by investigating associations between a psychometric-based phenotype with blood transcriptomics profiles of increased sympathetic nervous system (SNS) activation and brain imaging phenotypes in irritable bowel syndrome (IBS) participants and healthy controls (HCs).

Methods

A cross-sectional observational study design, transcriptomics profiling, multimodal brain imaging, and psychosocial assessments were obtained in 291 female and male IBS participants and HCs. Prior to analyses, unsupervised clustering was applied to derive high and low SR subgroups across participants based on two measures of SR. General linear models tested for SR group differences in clinical and biological parameters. Exploratory analyses examined associations between SR group-specific brain alterations and gene expression.

Results

The high, compared to low SR group showed greater cyclic AMP response element-binding protein (CREB) gene expression consistent with tonic SNS activity and proinflammatory changes in whole blood. Brain imaging showed neuroplastic changes in the high SR group consistent with an upregulation of ascending arousal systems and sensory processing and integration regions, and functional connectivity changes in the central autonomic network. SR moderated the sex difference in extraintestinal symptoms.

Conclusions

The findings support a model of tonically increased SNS activity as a plausible risk factor for increased autonomic reactivity to psychosocial stressors and low grade immune activation in both IBS and HCs, with a greater prevalence in IBS. These findings may have important implications for personalized treatment interventions in IBS.

Poor sleep and inflammatory gene expression among care partners of persons living with dementia: a pilot trial of a behavioral sleep intervention

Objective

Poor sleep is associated with increased inflammation, thereby increasing the risk of chronic diseases and mortality. However, the effects of behavioral sleep interventions on the upstream inflammatory system are unknown among family care partners (CP). The present study explored the role of a behavioral sleep intervention program on inflammatory gene expression.

Methods

This was part of a randomized controlled trial of a sleep intervention for dementia care dyads with sleep problems. Thirty dyads were randomized to sleep intervention or control groups. Sleep outcomes for CP were assessed with 1 week of actigraphy and sleep diary, and the Pittsburgh Sleep Quality Index. Other information included CP demographics, body mass index, and intensity of caregiving tasks. All outcomes were collected at baseline, post-treatment, and 3-month follow-up.

Results

Neither group showed any significant differential changes in gene expression from baseline to post-treatment or 3-month follow-up. A decrease in inflammatory gene expression was significantly associated with more nights of good sleep (i.e. nights without trouble falling or staying asleep at night). This finding remained significant after controlling for group (intervention/control), timepoint (baseline, post-treatment, and 3-month follow-up), and CP characteristics (e.g. age and ethnicity).

Conclusions

Although better sleep was associated with decreased inflammatory gene expression, this study did not demonstrate any benefits of a behavioral sleep intervention over control, most likely due to a small sample. Studies with larger sample sizes are needed to test the specific aspects of disturbed sleep that relate to inflammatory biology among CP of persons living with dementia.

Intersectional vulnerability in the relationship between discrimination and inflammatory gene expression

Addressing social disparities in health and well-being requires understanding how the effects of discrimination become biologically embedded, and how embedding processes might vary across different demographic contexts. Emerging research suggests that a threat-related gene expression response may contribute to social disparities in health. We tested a contextual vulnerability model of discrimination embedding using an empirical intersectionality (interaction discovery) analysis of pro-inflammatory gene expression in a national sample of non-institutionalized, English-speaking adults with RNA biomarker data (n = 543). At the time of data collection, the average age of participants was 55 years (SD = 13.26) and approximately half identified as female (50.46%). Most participants identified as White (∼73%) and had some college experience (∼60%). Results showed significant variation in the strength of association between daily discrimination and inflammatory gene expression by race and sex (b = -0.022; 95% CI:-0.038,-0.005, p = .009) with the estimated marginal association larger for racially-minoritized males (b = 0.007; 95% CI:-0.003,0.017, p = .163), compared to White males (b = -0.006; 95% CI:-0.013,0.001, p = .076). This study indicates that the link between daily discrimination and inflammatory gene expression may vary by sociodemographic characteristics. To improve initiatives and policies aimed at ameliorating disparities within populations, greater attention is needed to understand how interlocking systems of inequalities contribute to physiological health.