Maternal plasma and salivary anelloviruses in pregnancy and preterm birth

Introduction

Human anelloviruses, including torque teno virus (TTV) and torque teno mini virus (TTMV), are ubiquitous in the general population and have no known pathogenicity. We investigated the prevalence and viral load of TTV and TTMV in plasma and saliva over pregnancy, and assessed their association with spontaneous or medically indicated preterm birth.

Methods

This is a secondary analysis of the Measurement of Maternal Stress (MOMS) study, which recruited 744 individuals with singleton pregnancies from 4 US sites (Chicago, Pittsburgh, San Antonio, and rural Pennsylvania). Baseline outpatient visits took place in the second trimester (between 12'0 and 20'6/7  weeks' gestation), and follow-up visits in the third trimester (between 32'0 and 35'6/7  weeks' gestation). In a case-control study design, participants who delivered preterm (<37 weeks) resulting from spontaneous labor and/or preterm premature rupture of membranes ("sPTB") were compared with participants experiencing medically indicated preterm birth ("iPTB"), or delivery at term ("controls"). Plasma and saliva samples obtained during the second and third trimesters were tested for the presence and quantity of TTV and TTMV using real-time PCR. Demographic data were obtained via self-report, and clinical data via medical record review by trained research personnel.

Results

TTV was detected in plasma from 81% (second trimester) and 77% (third trimester) of participants, and in saliva from 64 and 60%. Corresponding detection rates for TTMV were 59 and 41% in plasma, and 35 and 24% in saliva. TTV and TTMV concentrations were similar between matched plasma and saliva samples. TTV prevalence and concentrations were not significantly different between groups (sPTB, iPTB, and controls). However, plasma TTMV in the third trimester was associated with sPTB and earlier gestational age at delivery. The iPTB group was not different from either the sPTB or the control group. In saliva, concentrations of TTV and TTMV were similar among the three groups. Both TTV and TTMV were more prevalent with increasing parity and were more common in Black and Hispanic participants compared to non-Hispanic White participants.

Conclusion

Anellovirus presence (specifically, TTMV) in the third trimester may be associated with preterm birth. Whether this association is causative remains to be determined.

Racial differences across pregnancy in maternal pro-inflammatory immune responsivity and its regulation by glucocorticoids

BACKGROUND

The distribution of adverse pregnancy, birth and subsequent child developmental and health outcomes in the U.S. is characterized by pronounced racial (particularly Black-white) disparities. In this context, chronic stress exposure represents a variable of considerable importance, and the immune/inflammatory system represents a leading candidate biological pathway of interest. Previous pregnancy studies examining racial disparities in immune processes have largely utilized circulating cytokine levels, and have yielded null or mixed results. Circulating cytokines primarily represent basal secretion and do not necessarily represent functional features of immune responsivity and regulation. Thus, in order to conduct a more in-depth characterization of racial differences in functional immune properties during pregnancy, we utilized an ex vivo stimulation assay, a dynamic measure of immune function at the cellular level, to investigate Black-white racial differences in in mid- and late-gestation in i) pro-inflammatory (IL-6) responsivity of leukocytes to antigen [lipopolysaccharide (LPS)] challenge, and ii) regulation (dampening) of this pro-inflammatory response by glucocorticoids.

METHOD

177 women (N = 42 Black (24%), n = 135 white (76%)) with a singleton, intrauterine pregnancy provided 20 mL venous blood in mid- (16.6 ± 2.4 wks) and late (33.3 ± 1.1 wks) pregnancy. Maternal pro-inflammatory responsivity of leukocytes was quantified by assessing the release of the pro-inflammatory cytokine IL-6 in response to LPS stimulation, and regulation of the pro-inflammatory response was quantified by assessing the suppression of the stimulated IL-6 response after co-incubation with progressively increasing levels of dexamethasone [10^-7, 10^-6, 10^-5 M] (i.e., glucocorticoid receptor resistance (GRR)). A priori model covariates included maternal age, parity, SES (socioeconomic status), and pre-pregnancy BMI.

RESULTS

Maternal pro-inflammatory responsivity (LPS-stimulated IL-6) and GRR increased significantly across mid- and late gestation (adjusted β = 0.157, p = 0.007; β = 0.627, p < 0.001, respectively). Across both time points in pregnancy Black women exhibited significantly higher LPS-stimulated IL-6 release and reduced glucocorticoid regulation of the IL-6 response (i.e., higher GRR) relative to white women, before and after adjusting for covariates (β = 0.381, p = 0.0030; β = 0.391, p = 0.0075, respectively). There was no racial difference in the concentrations of circulating IL-6 (p = 0.9199).

CONCLUSION

Our findings support the hypothesis postulating significant racial (Black-white) differences in key functional properties of the maternal immune system in pregnancy, which were not apparent using circulating cytokine measures. These data elucidate a potentially important physiological mechanism underlying the transduction of environmental conditions into racial disparities in reproductive and subsequent child health outcomes, and the use of these ex vivo measures should be considered in future studies.

Prospective association of maternal immune pro-inflammatory responsivity and regulation in pregnancy with length of gestation

PROBLEM

The immune system represents a leading pathway of interest in the pathophysiology of preterm birth. The majority of human clinical studies interrogating this pathway have utilized circulating immune biomarkers; however, these concentrations typically reflect only basal production but not key functional properties of the immune system, particularly variation in the pro-inflammatory response to antigen challenge and the regulation of this response. Thus, in this study, we utilized an ex vivo stimulation protocol that quantifies these processes, and we examined their prospective association with the gestation length and risk of preterm birth.

METHOD OF STUDY

Immune responsiveness and regulation were assessed in 128 pregnant women in mid-gestation using an ex vivo stimulation protocol. Maternal pro-inflammatory responsivity of leukocytes was quantified by assessing the release of the pro-inflammatory cytokines IL-6, TNF-α, and IL-1β in response to antigen stimulation, and regulation of the pro-inflammatory response was quantified by assessing the suppression of stimulated cytokine response upon co-incubation with increasing dexamethasone concentrations (ie, glucocorticoid receptor resistance; GRR).

RESULTS

Higher maternal GRR, indicating impaired regulation of the pro-inflammatory response, was significantly and independently associated with shorter gestational length (β = -0.42, p = .0091) and a 3.0-fold increase in risk for preterm birth (OR = 3.01, 95% CI = 1.17-7.70, p = .0218). Basal circulating IL-6 and TNF-α were not associated with either outcome.

CONCLUSION

The association of maternal GRR with length of gestation and preterm birth risk suggests that the processes represented by this measure-maternal pro-inflammatory propensity and immune regulation-may provide further mechanistic insight into the pathophysiology of preterm birth.

Early and current life adversity: Past and present influences on maternal diurnal cortisol rhythms during pregnancy

Stress during pregnancy affects maternal health and well-being, as well as the health and well-being of the next generation, in part through the hypothalamic-pituitary-adrenal (HPA) axis. Although most studies have focused solely on proximal experiences (i.e., during the pregnancy) as sources of prenatal stress, there has been a recent surge in studies that examine maternal early life adversity as a source of stress system dysregulation during pregnancy. The current study of 178 pregnant women examined the association of economic and life stress experienced during two time periods (i.e., childhood and pregnancy) with maternal HPA axis activity during the third trimester of pregnancy. Findings indicated that a current annual income of less than $15,000 and greater childhood disadvantage were associated with a flatter diurnal cortisol slope. Childhood maltreatment, particularly sexual abuse, was associated with a higher cortisol awakening response (CAR), even when controlling for recent adversity. We found some evidence that past adversity moderates the relationship between current adversity and diurnal cortisol, specifically for economic adversity and waking cortisol. Overall, our findings indicate that early life stressors play an important and underappreciated role in shaping stress biology during pregnancy.

Maternal socioeconomic disadvantage is associated with transcriptional indications of greater immune activation and slower tissue maturation in placental biopsies and newborn cord blood

Children from economically disadvantaged families experience worse cognitive, psychiatric, and medical outcomes compared to more affluent youth. Preclinical models suggest some of the adverse influence of disadvantage could be transmitted during gestation via maternal immune activation, but this hypothesis has not been tested in humans. It also remains unclear whether prenatal interventions can mitigate such effects. To fill these gaps, we conducted two studies. Study 1 characterized the socioeconomic conditions of 79 women during pregnancy. At delivery, placenta biopsies and umbilical blood were collected for transcriptional profiling. Maternal disadvantage was associated with a transcriptional profile indicative of higher immune activation and slower fetal maturation, particularly in pathways related to brain, heart, and immune development. Cord blood cells of disadvantaged newborns also showed indications of immaturity, as reflected in down-regulation of pathways that coordinate myeloid cell development. These associations were independent of fetal sex, and characteristics of mothers (age, race, adiposity, diabetes, pre-eclampsia) and babies (delivery method, gestational age). Study 2 performed the same transcriptional analyses in specimens from 20 women participating in CenteringPregnancy, a group-based psychosocial intervention, and 20 women in traditional prenatal care. In both placenta biopsies and cord blood, women in CenteringPregnancy showed up-regulation of transcripts found in Study 1 to be most down-regulated in conjunction with disadvantage. Collectively, these results suggest socioeconomic disparities in placental biology are evident at birth, and provide clues about the mechanistic origins of health disparities. They also suggest the possibility that psychosocial interventions could have mitigating influences.