Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - PrenatStressAging (Prenatal Stress and Programming of Newborn and Infant Telomere Biology and Cellular Aging)

Teaser

The long-term consequences of exposure to excess stress on the initiation and progression of many age-related diseases are well established. The period of intrauterine life represents among the most sensitive de-velopmental windows, at which time the effects of stress may be...

Summary

The long-term consequences of exposure to excess stress on the initiation and progression of many age-related diseases are well established. The period of intrauterine life represents among the most sensitive de-velopmental windows, at which time the effects of stress may be transmitted inter-generationally from a mother to her as-yet-unborn child. The elucidation of mechanisms underlying such effects is an area of in-tense interest and investigation. Aging, by definition, occurs with advancing age, and age-related disorders result from exposures over the life span of factors that produce and accumulate damage.

The novel concept advanced in this project is that the establishment of the integrity of key cellular aging-related processes that determine variation across individuals in the onset and progression of age-related disorders may originate very early in life (in utero) and may be plastic and influenced by developmental conditions. We propose that telomere biology and the epigenetic DNA methylation-based aging profile (DNAmAGE) represent can-didate outcomes of particular interest in this context. A prospective, longitudinal cohort study of 350 mother-child dyads is being conducted from early pregnancy through birth till one year of age.
Serial measures of maternal psychological, behavioral and physiological characteristics will be collected across gestation using an inno-vative ecological momentary assessment (EMA) based real-time, ambulatory sampling protocol.

The study addresses the following aims:

Aim 1: To estimate the nature and magnitude of the prospective association of maternal stress during pregnancy on markers of newborn and infant cellular aging (telomere biology, DNAmAGE). Hypothesis 1a): We hypothesize that EMA measures of maternal stress over gestation will be prospectively associated with shorter leukocyte TL (TL) at birth, steeper TL attrition over the first year of life, impaired mitogen-stimulated telomerase expression capacity at birth, and alterations in the DNAmAGE profile at birth and at 12 months age. We expect that the combination (interaction) of EMA measures of maternal psychosocial stress and psychobiological stress reactivity (i.e., change in heart rate or cortisol associated with a unit increase in psychological stress) will yield greater precision and predictive power than either measure alone. Hypothesis 1b): Because early gestation is hypothesized to be a particularly sensitive period for fetal programming, we expect that maternal stress measures in early gestation will be more strongly related to infant cellular aging than those in later gestation.

Aim 2: To test the hypothesis that alterations in key biomarkers of maternal-placental-fetal (MPF) endocrine, immune and oxidative stress biology during pregnancy mediate the effect of maternal stress exposure on newborn and infant cellular aging. The serial measures in early and late pregnancy of biomarkers that directly or indirectly reflect the MPF endocrine (CRH, cortisol) and immune (CRP, IL-6) and oxidative stress (8,12-isoprostane-F2alpha-VI) milieu across gestation will be used to determine the extent to which maternal MPF stress biology mediates the link between maternal prenatal stress (as defined in Aim 1) and newborn and infant cellular aging outcomes.

Aim 3: To test the hypothesis that the effects of maternal stress exposure on newborn and infant cellular aging are modulated by potentially modifiable maternal characteristics and states.


The study will help identify new strategies for risk identification and primary and secondary interventions to augment current efforts to prevent, delay and ameliorate age-related disorders.

Work performed

For the present project, a prospective, longitudinal cohort study of 350 mother-child dyads is being conducted from early pregnancy through birth till one year of age. Specific hypotheses about the effects of maternal stress and maternal-placental-fetal stress biology on newborn and infant telomere length, telomerase expression capacity, and an epigenetic aging-related profile will be addressed. Serial measures of maternal psychological, behavioral and physiological characteristics will be collected across gestation using an ecological momentary assessment (EMA) based real-time, ambulatory sampling protocol.

Currently, all study procedures are in place, recruitment is on track, study visits are running smoothly, and study retention and compliance of the study participants with the study protocol is very high.

Preliminary Findings:

As proposed in the current study and as recently conceptualized in a review paper that we published on this topic (Entringer et al., Philos Trans R Soc Lond B Biol Sci. 2018 Mar 5;373(1741). pii: 20170151), the initial (newborn) telomere length (TL) represents a critically important aspect of an individual’s telomere system across the lifespan. Adverse conditions in intrauterine life such as maternal stress during pregnancy are associated with shorter offspring TL at birth and in adult life. Alterations in stress-related immunological processes during pregnancy constitute a potential mediating biological pathway in this context because they can affect telomere length and telomerase activity via nuclear factor kappa B (NFκB)-mediated pathways. Thus, in data available from a small pilot sample, we tested if the balance between tumor necrosis factor-α (TNF-α), the major pro-inflammatory cytokine, and interleukin-10 (IL-10), the major anti-inflammatory cytokine, assessed throughout pregnancy, is related to leucocyte telomere length (LTL) of the newborn at birth. Participants were healthy women (N=108) recruited in early pregnancy. Concentrations of TNF- α and IL-10 were quantified in early, mid and late pregnancy from maternal blood samples. Telomere length was assessed in newborn blood samples within four weeks after birth. After adjusting for maternal age, maternal pre-pregnancy BMI, birth weight, gestational age at birth and infant sex, a higher mean TNF-α/IL-10 ratio across pregnancy was significantly associated with shorter newborn TL (β=-.205, p=.030, see Figure 9). These findings were presented at the Annual Conference of the International Society of Psychoneuroendocrinology 2017 (Lazarides et al., Psychoneuroendocrinology 83:27, September 2017), and have now been published in the journal Brain, Behavior and Immunity (Brain Behav Immun. 2019 Apr 8. pii: S0889-1591(19)30096-0. doi: 10.1016/j.bbi.2019.04.021. [Epub ahead of print])
This finding proves support for Aim 2 and provides new evidence in humans for a potential programming effect of pro-inflammatory processes during pregnancy on the newborn telomere system.

As previously reported, maternal stress during pregnancy has been shown to predict shorter newborn telomere length (TL). However, there is a lack of research on the role positive affect may play in protecting against the negative consequences of stress in the context of fetal programming of health and disease risk. Positive emotions may serve to buffer the psychological sequelae of maternal stress during pregnancy. We had access through a collaboration to a large data base in which one of the PhD students working on the current project was able to examined the relationship between maternal psychological resilience during pregnancy and newborn TL. The study sample consisted of 661 mother-child dyads from the Prediction and Prevention of Preeclampsia and Intrauterine Growth Restriction (PREDO) cohort. Pregnancy perceived stress, negative and positive emotional responses to pregnancy daily events, and positive affect were measured repeatedly throughout pregnancy Principal com

Final results

PROGRESS BEYOND THE STATE OF THE ART
The proposed study will help identify maternal conditions and intrauterine processes associated with her offspring’s long-term disease susceptibility for aging-related disorders. In the context of mother-child transmission of the effects of maternal stress we address specific knowledge gaps related to: a) ascertainment of the earliest period(s) of time during the offspring’s development when such trans-generational transmission may occur; b) elucidation of the primary biological pathways that may mediate this effect; and c) elucidation of stress-related maternal psychological, biophysical, obstetric, behavioral and potential stress-buffering states and conditions that may be amenable to interventions. For these reasons, I suggest this study represents the necessary and foundational step to move the field forward in an informed manner, in order to guide future translational research and identify targets for early identification of risk and for the subsequent development of intervention strategies. Moreover, I submit that even if the specific hypotheses are not supported there is considerable value in conducting the study and collecting these data for the following reasons. i) The newborn and infant telomere biology and epigenetics data will contribute to the greatly-needed currently-sparse data on the trajectory of these cellular characteristics in human infants; ii) The biosamples collected from this study will enable evaluation of alternate biological candidates in the context of fetal programming of health and disease risk; and iii) Because infants exposed to prenatal stress are at increased risk for mental and physical disorders, the establishment and longitudinal follow-up of this cohort will enable the characterization of developmental trajectories in this high-risk group.

INNOVATION
Innovative Paradigm. Instead of addressing the issue of susceptibility for common age-related disorders from only cumulative exposures of risk factors that produce and accumulate damage over the life span, we adopt the much less-frequently examined, alternate perspective of the fetal/ developmental origins approach. We suggest that telomere biology and DNAmAGE represent fundamental cellular (molecular) aging-related processes that are common across different cell types and tissues; that the integrity of the structure and function of these cellular aging-related processes depends, in part, on their initial (newborn) settings; and that this initial setting may be plastic and influenced by developmental conditions in the earliest stages of life.
Innovative characterization of maternal stress exposure. Instead of relying on conventional, self-report retrospective recall measures of stress, we will employ an alternate, innovative, state-of-the-art methodology -- EMA based real-time, ambulatory sampling of psychological, behavioral and biological states – in order to gain new, more precise information about the nature, magnitude and context-specificity of the effects of maternal stress and psychobiological stress reactivity on the outcomes of interest.
Innovative methods to assess cellular aging. The proposed study includes application of leading-edge methods to characterize the maximal capacity of cells to express telomerase (mitogen-stimulated cord blood mononuclear cell protocol) and a recently discovered DNA methylation based aging profile, coupled with state-of-the-art statistical modeling techniques for parametric and non-parametric repeated measures, time-series data. This will contribute to further defining technical capabilities in this field.