Prenatal programming of neuroendocrine reproductive function

It is now well recognized that the gestational environment can have long-lasting effects not only on the life span and health span of an individual but also, through potential epigenetic changes, on future generations. This article reviews the “prenatal programming” of the neuroendocrine systems that regulate reproduction, with a specific focus on the lessons learned using ovine models. The review examines the critical roles played by steroids in normal reproductive development before considering the effects of prenatal exposure to exogenous steroid hormones including androgens and estrogens, the effects of maternal nutrition and stress during gestation, and the effects of exogenous chemicals such as alcohol and environment chemicals. In so doing, it becomes evident that, to maximize fitness, the regulation of reproduction has evolved to be responsive to many different internal and external cues and that the GnRH neurosecretory system expresses a degree of plasticity throughout life. During fetal life, however, the system is particularly sensitive to change and at this time, the GnRH neurosecretory system can be “shaped” both to achieve normal sexually differentiated function but also in ways that may adversely affect or even prevent “normal function”. The exact mechanisms through which these programmed changes are brought about remain largely uncharacterized but are likely to differ depending on the factor, the timing of exposure to that factor, and the species. It would appear, however, that some afferent systems to the GnRH neurons such as kisspeptin, may be critical in this regard as it would appear to be sensitive to a wide variety of factors that can program reproductive function. Finally, it has been noted that the prenatal programming of neuroendocrine reproductive function can be associated with epigenetic changes, which would suggest that in addition to direct effects on the exposed offspring, prenatal programming could have transgenerational effects on reproductive potential

Prenatal programming of later performance in dairy cattle = Prenatale programmering van latere prestaties bij melkvee

Prenatal programming refers to the fact that insults during pre- and early postnatal life can have long-term consequences on the health and performance. In diary cattle, physiological conditions, such as maternal body growth, milk yield and parity, and environmental conditions during gestation can create a suboptimal environment for the developing fetus. As a consequence, adaptations of the placental and newborn phenotype take place. In addition, potential long-term effects of prenatal programming influence body growth, fertility, milk yield and longevity in dairy cows. These results suggest that the current management systems may pose a risk for the long-term health and performance of dairy cattle. Hence, in management practices, all pre- and postnatal aspects should carefully be considered in order to raise healthier and more productive dairy cows

Testing three hypotheses about effects of sensitive-insensitive parenting on telomeres.

Telomeres are the protective DNA-protein sequences appearing at the ends of chromosomes; they shorten with each cell division and are considered a biomarker of aging. Shorter telomere length and greater erosion have been associated with compromised physical and mental health and are hypothesized to be affected by early life stress. In the latter case, most work has relied on retrospective measures of early life stressors. The Dutch research (n = 193) presented herein tested 3 hypotheses prospectively regarding effects of sensitive-insensitive parenting during the first 2.5 years on telomere length at age 6, when first measured, and change over the following 4 years. It was predicted that (1) less sensitive parenting would predict shorter telomeres and greater erosion and that such effects would be most pronounced in children (2) exposed to prenatal stress and/or (3) who were highly negatively emotional as infants. Results revealed, only, that prenatal stress amplified parenting effects on telomere change-in a differential-susceptibility-related manner: Prenatally stressed children displayed more erosion when they experienced insensitive parenting and less erosion when they experienced sensitive parenting. Mechanisms that might initiate greater postnatal plasticity as a result of prenatal stress are highlighted and future work outlined. (PsycINFO Database Record (c) 2020 APA, all rights reserved)

Prenatal dexamethasone ‘programmes’ hypotension, but stress-induced hypertension in adult offspring

Low birth weight in humans is predictive of hypertension in adult life. Although the mechanisms underlying this link remain unknown, fetal overexposure to glucocorticoids has been implicated. We previously showed that prenatal dexamethasone (DEX) exposure in the rat lowers birth weight and programmes adult hypertension. The current study aimed to further investigate the nature of this hypertension and to elucidate its origins. Unlike previous studies, we assessed offspring blood pressure (BP) with radiotelemetry, which is unaffected by stress artefacts of measurement. We show that prenatal DEX during the last week of pregnancy results in offspring of low birth weight (14% reduction) that have lower basal BP in adulthood (∼4–8 mmHg lower); with the commonly expected hypertensive phenotype only being noted when these offspring are subjected to even mild disturbance or a more severe stressor (up to 30 mmHg higher than controls). Moreover, DEX-treated offspring sustain their stress-induced hypertension for longer. Promotion of systemic catecholamine release (amphetamine) induced a significantly greater rise of BP in the DEX animals (77% increase) over that observed in the vehicle controls. Additionally, we demonstrate that the isolated mesenteric vasculature of DEX-treated offspring display greater sensitivity to noradrenaline and other vasoconstrictors. We therefore conclude that altered sympathetic responses mediate the stress-induced hypertension associated with prenatal DEX programming

Development of the Family Poverty Index (FPI): A Novel Index to Measure Socioeconomic Status

The CANDLE Study aims to uncover factors experienced during pregnancy and early life that affect cognition, behavior, and health of children. External stressors and socioeconomic status (SES) influence the fetus through “prenatal programming”. However, comprehensive measures of SES do not exist, except those based on income and education. We selected 53 variables from the CANDLE study including annual household income, headcount, marital status, health insurance, parental occupation and education. Singular value decomposition imputation (SVDI), a principal components analysis approach unaffected by the 24.4% missing data in our variables, was applied to all 53 variables (Troyanskaya, 2001). All variables were distilled into 3 principal components explaining 93% of the variability. These components were combined to develop the Family Poverty Index (FPI, range 1-10). All subjects were separated into deciles based on FPI scores. Individuals with FPI=1 were the “poorest” with 79% individuals having annual incomes \u3c$15,000. Those with FPI=9 or 10 were “rich”, since most individuals (98.7$55,000. With FPI=1-3, 95% had Medicaid insurance and 4.8% had employer/private insurance, whereas with FPI=8-10, 86% had employer/private insurance and 11.8% had Medicaid. Other variables showed similar distributions across FPI categories. FPI appears to be a robust measure of SES in the CANDLE Study population. Further research should test the validity of the FPI in other datasets

Appetite Regulatory Neural Circuitry in the Prenatal Testosterone Treated and Obese Ewe

Body weight and energy expenditure are regulated by the nervous systerfi. The first aim of this thesis was to characterize appetite regulatory neurons in the sheep brain which express both agouti-related protein (AgRP) and neuropeptide Y (NPY), or proopiomelanocortin (POMC) and cocaine- and amphetamine- regulated transcript (CART). We then asked whether this circuitry is altered in ewes at increased risk of obesity following prenatal testosterone (T) treatment, or in diet-induced obese ewes. Using immunocytochemistry, we found that prenatal T-treated ewes showed increased expression of the appetite stimulatory peptide, AgRP, but not the inhibitory peptide, POMC, consistent with the increased risk of obesity in these animals. In contrast, chronic diet-induced obesity led to decreased AgRP and increased POMC, suggesting compensatory mechanisms to reverse the obese state. Overall, our results suggest that distinct changes in metabolic control neurons are associated with increased predisposition, as well as expression, of obesity in adult sheep

Prenatal programming of child neurocognitive abilities and maternal mental health : Fetal Programming

Maternal mental health problems during pregnancy, especially mood and anxiety disorders and symptoms, are common. They not only hinder maternal well-being and health during pregnancy but also are associated with physical and mental health adversities in the offspring. We provide here a review of the studies published between 2017 and 2019, which reported on the associations between maternal mental health problems during pregnancy and child neurocognitive outcomes. We identified eight studies, which reported a mixed pattern of findings. While the balance of evidence favors lack of associations, small sample sizes and heterogeneity in study designs, exposures, outcomes, and covariate adjustments between the studies preclude firm conclusions. The reviewed studies encourage further research filling in the knowledge gaps we identified.Peer reviewe

Additive drug-specific and sex-specific risks associated with co-use of marijuana and tobacco during pregnancy: Evidence from 3 recent developmental cohorts (2003-2015).

BACKGROUND: Methodologic challenges related to the concomitant use (co-use) of substances and changes in policy and potency of marijuana contribute to ongoing uncertainty about risks to fetal neurodevelopment associated with prenatal marijuana use. In this study, we examined two biomarkers of fetal neurodevelopmental risk-birth weight and length of gestation-associated with prenatal marijuana use, independent of tobacco (TOB), alcohol (ALC), other drug use (OTH), and socioeconomic risk (SES), in a pooled sample (N = 1191) derived from 3 recent developmental cohorts (2003-2015) with state-of-the-art substance use measures. We examined differential associations by infant sex, and multiplicative effects associated with co-use of MJ and TOB. METHODS: Participants were mother-infant dyads with complete data on all study variables derived from Growing Up Healthy (n = 251), Behavior and Mood in Babies and Mothers (Cohorts 1 and 2; n = 315), and the Early Growth and Development Study (N = 625). We estimated direct effects on birth weight and length of gestation associated with MJ, TOB, and co-use (MJ x TOB), using linear regression analysis in the full sample, and in male (n = 654) and female (n = 537) infants, separately. RESULTS: Mean birth weight and length of gestation were 3277 g (SD = 543) and 37.8 weeks (SD = 2.0), respectively. Rates of prenatal use were as follows: any use, n = 748 (62.8%); MJ use, n = 273 (22.9%); TOB use, n = 608 (51.0%); co-use of MJ and TOB, n = 230 (19.3%); ALC use, n = 464 (39.0%); and OTH use n = 115 (9.7%.) For all infants, unique effects on birth weight were observed for any MJ use [B(SE) = -84.367(38.271), 95% C.I. -159.453 to -9.281, p = .028], any TOB use [B(SE) = -0.99.416(34.418), 95% C.I. -166.942 to -31.889, p = .004], and each cigarette/day in mean TOB use [B(SE) = -12.233(3.427), 95% C.I. -18.995 to -5.510, p \u3c .001]. Additional effects of co-use on birth weight, beyond these drug-specific effects, were not supported. In analyses stratified by sex, while TOB use was associated with lower birth weight in both sexes, MJ use during pregnancy was associated with lower birth weight of male infants [B(SE) = -153.1 (54.20); 95% C.I. -259.5 to -46.7, p = .005], but not female infants [B(SE) = 8.3(53.1), 95% C.I. -96.024 to 112.551, p = .876]. TOB, MJ, and their co-use were not associated with length of gestation. CONCLUSIONS: In this sample, intrauterine co-exposure to MJ and TOB was associated with an estimated 18% reduction in birth weight not attributable to earlier delivery, exposure to ALC or OTH drugs, nor to maternal SES. We found evidence for greater susceptibility of male fetuses to any prenatal MJ exposure. Examination of dose-dependence in relationships found in this study, using continuous measures of exposure, is an important next step. Finally, we underscore the need to consider (a) the potential moderating influence of fetal sex on exposure-related neurodevelopmental risks; and (b) the importance of quantifying expressions of risk through subtle alterations, rather than dichotomous outcomes