At the forefront of psychoneuroimmunology in pregnancy: Implications for racial disparities in birth outcomes: PART 2: Biological mechanisms

Moving toward affective immunology: Legacy and future directions

The term "affective immunology" has recently been used to denote a field focused on the interplay between affective processes (including mood states, specific emotions, and regulatory processes) and various aspects of immune function. The overarching goals of this commentary are a) to provide historical underpinnings of this field with a focus on the profound impact of the work of Janice Kiecolt-Glaser, who is further honored in this special issue, b) to review important off-shoots of her legacy work in this domain, and c) to highlight important future directions for the field. Kiecolt-Glaser's work laid much of the foundation for affective immunology, with groundbreaking research related to depression, hostility and dyadic interactions, loneliness, and other affective patterns, often in the context of holistic models, novel experimental designs, and interventions. Her former mentees (and many of their mentees) have carried on her legacy in these domains, in ways that continue to advance appreciation of how affective processes relate to immune function. There are numerous remaining questions for the field to pursue, including better understanding of the role of emotion regulation, emotional reactivity and recovery, restorative processes, affective variability, and developmental and dynamic social processes. Such work will require greater use of longitudinal and within-person approaches and/or examination of processes in daily life, as well as models that account for interactive and reciprocal processes and which integrate behavior, social context, sociocultural factors, individual differences, and other aspects of health. As more work in these domains continues, building on Kiecolt-Glaser's rich legacy, we move toward the emergence of affective immunology as an important subfield in the domain of psychoneuroimmunology, one which will offer more nuanced understanding of the role of affective processes in immune health.

Accelerated epigenetic clock aging in maternal peripheral blood and preterm birth

BACKGROUND

Epigenetic clocks use CpG DNA methylation to estimate biological age. Acceleration is associated with cancer, heart disease, and shorter life span. Few studies evaluate DNA methylation age and pregnancy outcomes. AgeAccelGrim is a novel epigenetic clock that combines 7 DNA methylation components.

OBJECTIVE

This study aimed to determine whether maternal biological aging (via AgeAccelGrim) is associated with early preterm birth.

STUDY DESIGN

A prospective cohort of patients with singleton pregnancies and at high risk of spontaneous preterm birth delivering at a tertiary university hospital were included in this study. Genome-wide CpG methylation was measured using the Illumina EPIC BeadChip (Illumina, Inc, San Diego, CA) from maternal blood samples obtained at <28 weeks of gestation. AgeAccelGrim and its 7 DNA methylation components were estimated by the Horvath DNA methylation age online tool. Positive values are associated with accelerated biological aging, whereas negative values are associated with slower biological aging relative to each subject's age. The primary outcome was preterm birth at <34 weeks of gestation (any indication). The secondary outcomes were preterm birth at <37 and <28 weeks of gestation. AgeAccelGrim was analyzed as a continuous variable and in quartiles. Exploratory analyses evaluated each of the 7 DNA methylation components included in the composite AgeAccelGrim. Data were analyzed by chi-square test, t test, rank-sum test, logistic regression (controlling a priori for maternal age, cell counts, low socioeconomic status, and gestational age at the time of sample collection), and Kaplan-Meier survival analyses. The log-rank test was used to test the equality of the survival functions.

RESULTS

Overall, 163 patients met the inclusion criteria. Of the patients, 48%, 39%, and 21% delivered at <37, <34, and <28 weeks of gestation, respectively. The median AgeAccelGrim was -0.35 years (interquartile range, -2.24 to 1.31) for those delivering at term. Those delivering preterm had higher AgeAccelGrim values that were inversely proportional to delivery gestational age (preterm birth at <37 weeks of gestation: +0.40 years [interquartile range: -1.21 to +2.28]; preterm birth at <34 weeks of gestation: +0.51 years [interquartile range: -1.05 to +2.67]; preterm birth at <28 weeks of gestation: +1.05 years [interquartile range: -0.72 to +2.72]). Estimated DNA methylation of the 7 epigenetic clock component values was increased among those with preterm birth at <34 weeks of gestation, although the differences were only significant for DNA methylation of plasminogen activation inhibitor 1. In regression models, AgeAcccelGrim was associated with an elevated risk of preterm birth with increasing magnitude for increasing severity of preterm birth. For each 1-year increase in the AgeAccelGrim value (ie, each 1-year increase in biological age compared with chronologic age), the adjusted odds of preterm birth were 11% (adjusted odds ratio, 1.11; 95% confidence interval, 1.00-1.24), 13% (adjusted odds ratio, 1.13; 95% confidence interval, 1.01-1.26), and 18% (adjusted odds ratio, 1.18; 95% confidence interval, 1.04-1.35) higher for preterm birth at <37, <34, and <28 weeks of gestation, respectively. Similarly, individuals with accelerated biological aging (≥75th percentile AgeAccelGrim) had more than double the odds of preterm birth at <34 weeks of gestation (adjusted odds ratio, 2.36; 95% confidence interval, 1.10-5.08) and more than triple the odds of preterm birth at <28 weeks of gestation (adjusted odds ratio, 3.89; 95% confidence interval, 1.61-9.38). The adjusted odds ratio for preterm birth at <37 weeks of gestation was 1.73 but spanned the null (adjusted odds ratio, 1.73; 95% confidence interval, 0.81-3.69). In Kaplan-Meier survival analyses, those in the highest AgeAccelGrim quartile delivered the earliest (log-rank P value of <.001).

CONCLUSION

Accelerated biological aging was associated with preterm birth among high-risk patients. Future research confirming these findings and elucidating factors that slow biological aging may improve birth outcomes.

Regulatory T-cell phenotypes in prenatal psychological distress

BACKGROUND

Experiencing symptoms of psychological distress during pregnancy is common and has been linked to dysregulated immune functioning. In this context, immunoregulatory function is especially relevant because of its crucial role in establishment and maintenance of healthy pregnancy. However, little research has examined associations between women's prenatal psychological distress and immunoregulatory biomarkers. We investigated how symptoms of depression, anxiety, and stress relate to circulating levels of regulatory T-cells (Tregs).

MATERIALS AND METHODS

Pregnant Latina women were assessed at around 12 weeks of pregnancy (N = 82). These assessments included blood draws and self-report questionnaires assessing symptoms of depression, state anxiety, pregnancy-related anxiety, and perceived stress. Flow cytometry on PBMCs was used to quantify circulating Tregs, defined as CD3+CD4+CD25hiCD127loFoxP3+, and subpopulations positive for one of the following intra- or extracellular markers, CD45RA, CTLA-4, Helios, PD-1, TIM-3, and TIGIT. We collected 82 samples at 12 weeks. Multivariable linear regressions tested for associations between symptoms of psychological distress and Treg concentrations, adjusted for gestational age.

RESULTS

State anxiety symptoms at 12 weeks were negatively associated with parent Treg cell levels (b = -4.02, p = 0.023) and subpopulations Helios+ (b = -3.29, p = 0.019) and TIM3+ (b = -3.17, p = 0.008). Perceived stress was negatively associated with the PD-1+ subpopulation at 12 weeks (b = -4.02, p = 0.023). Depression was not related to Tregs or the subpopulations.

CONCLUSION

Our observation that symptoms of anxiety and stress are related to tolerogenic immunology suggests a possible biomechanism explaining correlations of maternal mood disorders with adverse outcomes for mothers and offspring.

Elevating Voices, Addressing Depression, Toxic Stress, and Equity Through Group Prenatal Care: A Pilot Study

Introduction

Elevating Voices, Addressing Depression, Toxic Stress and Equity (EleVATE) is a group prenatal care (GC) model designed to improve pregnancy outcomes and promote health equity for Black birthing people. This article outlines the foundational community-engaged process to develop EleVATE GC and pilot study results.

Methods

We used community-based participatory research principles and the Ferguson Commission Report to guide creation of EleVATE GC. The intervention, designed by and for Black birthing people, centers trauma-informed care, antiracism, and integrates behavioral health strategies into group prenatal care to address unmet mental health needs. Using a convenience sample of patients seeking care at one of three safety-net health care sites, we compared preterm birth, small for gestational age, depression scores, and other pregnancy outcomes between patients in individual care (IC), CenteringPregnancy™ (CP), and EleVATE GC.

Results

Forty-eight patients enrolled in the study (n=11 IC; n=14 CP; n=23 EleVATE GC) and 86% self-identified as Black. Patients participating in group prenatal care (EleVATE GC or CP) were significantly less likely to experience a preterm birth <34 weeks. Rates of small for gestational age, preterm birth <37 weeks, depression scores, and other pregnancy outcomes were similar across groups. Participants in CP and EleVATE GC were more likely to attend their postpartum visit and breastfeed at hospital discharge than those in IC.

Discussion

Our findings model a systematic approach to design a feasible, patient-centered, community-based, trauma-informed, antiracist intervention. Further study is needed to determine whether EleVATE GC improves perinatal outcomes and promotes health equity.

Association between neutrophil-lymphocyte ratio and perinatal depressive symptoms among Chinese women

OBJECTIVE

The prevalence of depression has increased dramatically in the past few decades, and pregnant women are at high risk for depression. It is widely thought that inflammation plays a critical role in the pathogenesis of depression. Therefore, we aimed to evaluate the association between the neutrophil-lymphocyte ratio (NLR), a marker of chronic immune inflammation, and perinatal depressive symptoms.

METHODS

A cohort study involving 535 pregnant women was conducted based on a prospective birth cohort in Wuhan, China. The Edinburgh Postnatal Depression Scale (EPDS) was used to assess antepartum depression (APD) and postpartum depression (PPD) during the second trimester of pregnancy and one month after delivery. The NLR during the second trimester was determined based on a routine blood test. The association between NLR and depressive symptoms was evaluated using logistic regression analysis and restricted cubic spline (RCS) regression.

RESULTS

We found that the prevalence of APD and PPD was 8.4% and 15.1%, respectively. NLR levels were positively associated with APD (OR = 1.52, 95% CI: 1.20--1.91). After adjusting for potential confounders, the OR (95% CI) of APD for the highest NLR quartile was 4.56 (1.58, 13.13) compared with the lowest quartile. No significant association was found between NLR and PPD. RCS regression model analysis indicated a linear correlation between NLR and APD (P for non-linearity = 0.58).

CONCLUSION

Overall, elevated mid-trimester NLR is independently associated with APD but not PPD.

Psychosocial and behavioral factors affecting inflammation among pregnant African American women

African American women are reported to have greater inflammation compared with women from other racial groups. Higher inflammation during pregnancy has been associated with increased risk of adverse perinatal outcomes. We hypothesized that maternal inflammation is related to depressive symptoms and social and behavioral risk factors among pregnant African American women. Pregnant African American women (n ​= ​187) were recruited at prenatal clinics in the Midwest. Women completed questionnaires and had blood drawn at a prenatal visit. Plasma levels of cytokines (interferon gamma [IFN]-γ, interleukin [IL]-6, IL-8, IL-10, tumor necrosis factor [TNF]-α) and C-reactive protein (CRP) were measured by multiplex assays. Women had a mean age of 26.58±5.42 years and a mean gestational age at data collection of 16.35±5.95 weeks. Twenty-six percent of women had Center for Epidemiological Studies-Depression (CES-D) scores ≥23 (scores that have been correlated with clinical diagnosis of depression), 15.5% smoked cigarettes, 16.6% used marijuana, and 5.3% reported experiencing intimate partner violence (IPV). Higher CES-D scores were correlated with higher plasma CRP levels (r ​= ​0.16, p ​= ​0.046). Women who reported any experiences of IPV during pregnancy had higher levels of IL-8 (p ​= ​0.018) and lower levels of IFN-γ (p ​= ​0.012) compared with women who did not report IPV. Cigarette smoking during pregnancy was associated with lower levels of the anti-inflammatory cytokine IL-10 (p ​= ​0.003). These findings suggest that depressive symptoms, IPV, and cigarette smoking during pregnancy relate to select inflammatory markers in pregnant African American women. The relationships of inflammation with these factors should be further investigated to better understand the mechanisms which influence maternal and fetal health outcomes.

•

Depressive symptoms are related to higher levels of CRP in pregnant African American Women.

•

Intimate partner violence in pregnancy is related to higher interleukin 8 levels.

•

Smoking during pregnancy is associated with lower interleukin 10 levels.

•

Inflammation is related to depressive symptoms, intimate partner violence and smoking in pregnant African American women.

Lifetime stressor exposure, systemic inflammation during pregnancy, and preterm birth among Black American women

Although Black American mothers and infants are at higher risk for morbidity and mortality than their White counterparts, the biological mechanisms underlying these phenomena remain largely unknown. To investigate the role that lifetime stressor exposure, perceived stressor severity, and systemic inflammatory markers might play, we studied how these factors were interrelated in 92 pregnant Black American women. We also compared inflammatory marker levels for women who did versus did not go on to give birth preterm. During the early third trimester, women completed the Stress and Adversity Inventory for Adults to assess the stressors they experienced over their lifetime. Women also provided blood samples for plasma interleukin (IL)-6, IL-8, IL-1β, and tumor necrosis factor (TNF)-α quantification. Preterm births were identified by medical record review. Controlling for relevant covariates, there were significant positive associations between average levels of both overall and acute perceived stressor severity and plasma IL-1β levels. Controlling for perceived stress at assessment and exposure to racial discrimination did not affect these results. Mediation models revealed that exposure to more chronic stressors was related to higher plasma IL-1β levels, as mediated by higher average levels of overall perceived stressor severity. Exposure to fewer acute stressors was related to higher plasma IL-1β levels, as mediated by higher average levels of acute perceived stressor severity. Finally, women who went on to give birth preterm had higher levels of plasma IL-6. These data thus highlight the potential importance of assessing and addressing lifetime stressor exposure among mothers before and during maternal-infant care.

Differences in Psychosocial Protective Factors by Race/Ethnicity and Socioeconomic Status and Their Relationship to Preterm Delivery

Background: Non-Hispanic Black (“Black”) women in the United States deliver preterm at persistently higher rates than non-Hispanic White (“White”) women, and disparities in preterm delivery (PTD) also exist by socioeconomic factors. Research is needed to identify and understand factors that are protective against PTD for Black women and low socioeconomic status (SES) women.

Methods: We examined seven potential protective factors at the individual, interpersonal, and neighborhood levels during pregnancy to determine if they (1) differed in prevalence by race/ethnicity and SES and (2) were associated with risk of PTD overall or within specific race/ethnicity and SES groups. We used prospectively collected data from n = 2474 women who were enrolled in the Pregnancy Outcomes and Community Health Study conducted in Michigan (1998–2004).

Results: White women reported higher levels of self-esteem, mastery, perceived social support, instrumental social support, and reciprocity compared to Black women (all p < 0.01), while Black women reported higher levels of religiosity compared to white women (p < 0.01). High SES women reported higher levels of all protective factors compared to middle and low SES women (all p < 0.01). While protective factors were not independently associated with PTD, religiosity was associated with lower odds of PTD among low SES women (OR 0.6, 95% CI 0.4-0.9) and among Black women (OR 0.6, 95% CI 0.4–1.0), respectively.

Conclusions: Our findings highlight the importance of assessing how protective factors may operate differently across race/ethnicity and SES to promote healthy pregnancy outcomes. Future studies should examine mechanisms that elucidate potential causal pathways between religiosity and PTD for Black women and low SES women.

The contribution of racism-related stress and adversity to disparities in birth outcomes: evidence and research recommendations

Currently, racial and ethnic differences in adverse birth outcomes and infant mortality are some of the largest and most persistent health disparities in the United States. This narrative review article synthesizes existing literature to present a conceptual model of how racism-related stress and adversity are critical determinants of such disparities. We describe how historical and ongoing racism has created conditions wherein women of color are disproportionately exposed to chronic, multilayered stress and adversity and how the biological consequences of exposure to these stressors confers risk for adverse birth outcomes. Next, we identify important priorities and considerations for future research, including the heterogeneity of racism-related stressors, biomarkers and mechanisms, chronicity and sensitive periods of exposure, developmental programming of lifespan health, resilience, and community-engaged research methodologies.

•

Historical and ongoing racism has created conditions wherein women of color are disproportionately exposed to stress and adversity.

•

The consequences of exposure to racism-related stress and adversity can confer risk for health conditions implicated in adverse birth outcomes and alter maternal physiology associated with fetal development and timing of parturition.

•

Conjointly studying racism-related stress, biologic profiles, and birth outcomes is a priority for future research.

•

It is important to identify factors that mitigate the impact of racism-related stress and adversity on birth outcomes.

A biopsychosocial framework for understanding sexual and gender minority health: A call for action

The number of US adults identifying as lesbian, gay, bisexual, transgender, or a different sexual identity has doubled since 2008, and about 40 % of the sexual and gender minority population identify as people of color. Minority stress theory posits that sexual and gender minorities are at particular risk for stress via stigma and discrimination at the structural, interpersonal, and individual levels. This stress, in turn, elevates the risk of adverse health outcomes across several domains. However, there remains a conspicuously limited amount of research on the psychoneuroimmunology of stress among sexual and gender minorities. We developed the Biopsychosocial Minority Stress Framework which posits that sexual minority status leads to unique experiences of minority stress which results in adverse health behavioral factors, elevated psychological distress and sleep disturbance, and immune dysregulation. Moderators in the model include both individual differences and intersectional identities. There is a crucial need to understand the biological-psychological axis of stress among the increasingly visible sexual and gender minority population to increase their health, longevity, and quality of life.