Report on the 2nd World Congress on Fetal Origins of Adult Disease, Brighton, U.K., June 7-10, 2003

Exposures during the prepuberty period and future offspring's health: evidence from human cohort studies†

Emerging evidence suggests that exposures in prepuberty, particularly in fathers-to-be, may impact the phenotype of future offspring. Analyses of the RHINESSA cohort find that offspring of father’s exposed to tobacco smoking or overweight that started in prepuberty demonstrate poorer respiratory health in terms of more asthma and lower lung function. A role of prepuberty onset smoking for offspring fat mass is suggested in the RHINESSA and ALSPAC cohorts, and historic studies suggest that ancestral nutrition during prepuberty plays a role for grand-offspring’s health and morbidity. Support for causal relationships between ancestral exposures and (grand-)offspring’s health in humans has been enhanced by advancements in statistical analyses that optimize the gain while accounting for the many complexities and deficiencies in human multigeneration data. The biological mechanisms underlying such observations have been explored in experimental models. A role of sperm small RNA in the transmission of paternal exposures to offspring phenotypes has been established, and chemical exposures and overweight have been shown to influence epigenetic programming in germ cells. For example, exposure of adolescent male mice to smoking led to differences in offspring weight and alterations in small RNAs in the spermatozoa of the exposed fathers. It is plausible that male prepuberty may be a time window of particular susceptibility, given the extensive epigenetic reprogramming taking place in the spermatocyte precursors at this age. In conclusion, epidemiological studies in humans, mechanistic research, and biological plausibility, all support the notion that exposures in the prepuberty of males may influence the phenotype of future offspring.

Influence of residential greenness on adverse pregnancy outcomes: A systematic review and dose-response meta-analysis

BACKGROUND

With the development of urbanization, there is a decreasing tendency for people contact with natural greenness. Whether maternal exposure to greenness has an impact on pregnancy complications and pregnancy outcomes remains to be confirmed.

OBJECTIVES

To estimate the association and dose-response relationship between residential greenness and pregnancy outcomes.

DATA SOURCES

PubMed, Embase, Ovid, Scopus and Web of Science from inception to 1st December 2019 were searched.

SYNTHESIS METHODS

The summary regression coefficient (β) and odds ratio (OR) with corresponding 95% confidence interval (95%CI) were calculated. The linear dose-response relationship between greenness and adverse pregnancy outcomes was also investigated.

RESULTS

Overall, 36 studies with a total of 11,983,089 participants were included. Birth weight was significantly higher in highest level of greenness exposure group compared to lowest level group (e.g. β:20.22, 95%CI:13.50-26.93 at 100 m buffer). The odds of low birth weight (LBW) decreased in the highest level of group compared to lowest level group (e.g. OR:0.86, 95%CI:0.75-0.99 at 100 m buffer). The odds of small for gestational age (SGA) also decreased in the highest group (OR:0.93, 95%CI:0.88-1.00 at 100 m buffer). In addition, maternal exposure to greenness was associated with increased head circumference and decreased mental disorders. The dose-response models showed a 2% decrease risk of LBW per 0.1 normalized difference vegetation index (NDVI) increase within 300 m buffer (OR:0.98, 95%CI:0.97-0.99, P < 0.001) and a 1% decrease risk of SGA per 0.1 NDVI increase within 300 m buffer (OR:0.99, 95%CI:0.98-1.00, P = 0.037). No significant associations were found on preterm birth, gestational age, gestational diabetes mellitus, gestational hypertension or preeclampsia.

CONCLUSIONS

This review confirms an inverse association between residential greenness and adverse pregnancy outcomes. Findings of our study provide evidences for pregnant women to increase greenness exposure.

Intrauterine growth restriction impairs right ventricular response to hypoxia in adult male rats

BACKGROUND

Intrauterine growth restriction (IUGR) predisposes to cardiovascular diseases in adulthood. The mechanisms of this phenomenon remain cryptic. We hypothesized that heart mitochondria in IUGR-born adult rats are more sensitive to acute hypoxia which translates into dysfunctional cardiac response to hypoxic stress.

METHODS

Adult IUGR-born male rats (the offspring of dams fed with calories-restricted diet during pregnancy) were exposed to acute hypoxic stress with echocardiographic assessment of cardiac function. In parallel, mitochondrial respiration in organelles isolated from left ventricle (LV) and right ventricle (RV) was tested in normoxic and anoxic conditions. The extent of post-anoxic inhibition of mitochondrial respiration and cardiac function was compared with controls, non-IUGR rats.

RESULTS

Compared with controls, in the IUGR rats hypoxia significantly reduced only RV contractility, evidenced by decreased fractional shortening, functional area of contraction, and tricuspid annular plane systolic excursion. In isolated mitochondria, anoxic challenge inhibited respiratory chain in both groups of rats. However, compared with controls, the extent of anoxic mitochondrial depression was significantly greater in IUGR-born rats, but only in the organelles isolated from RV.

CONCLUSIONS

In adult IUGR-born rats, mitochondria from RV are hypersensitive to oxygen deprivation and this translates into maladaptive RV cardiac response to acute hypoxia.

Adult responses to an ischemic stroke in a rat model of neonatal stress and morphine treatment

Critically ill newborn infants experience stressors that may alter brain development. Using a rodent model, we previously showed that neonatal stress, morphine, and stress plus morphine treatments each influence early gene expression and may impair neurodevelopment and learning behavior. We hypothesized that the combination of neonatal stress with morphine may alter neonatal angiogenesis and/or adult cerebral blood vessel density and thus increase injury after cerebral ischemia in adulthood. To test this, neonatal Lewis rats underwent 8 h/d maternal separation, plus morning/afternoon hypoxia exposure and either saline or morphine treatment (2 mg/kg s.c.) from postnatal day 3-7. A subset received bromodeoxyuridine to track angiogenesis. Adult brains were stained with collagen IV to quantify cerebral blood vessel density. To examine vulnerability to brain injury, postnatal day 80 adult rats underwent right middle cerebral artery occlusion (MCAO) to produce unilateral ischemic lesions. Brains were removed and processed for histology 48 h after injury. Brain injury was assessed by histological evaluation of hematoxylin and eosin, and silver staining. In contrast to our hypothesis, neither neonatal morphine, stress, nor the combination affected cerebral vessel density or MCAO-induced brain injury. Neonatal angiogenesis was not detected in adult rats possibly due to turnover of endothelial cells. Although unrelated to angiogenesis, hippocampal granule cell neurogenesis was detected and there was a trend (P = 0.073) toward increased bromodeoxyuridine incorporation in rats that underwent neonatal stress. These findings are discussed in contrast to other data concerning the effects of morphine on cerebrovascular function, and acute effects of morphine on hippocampal neurogenesis.

Mechanisms of obesity-induced male infertility

Male infertility, characterized by hypogonadism, decreased semen quality or ejaculatory dysfunction, accounts for approximately 20% of infertility cases. Obesity and metabolic dysfunction have been identified, among other causal factors, to contribute to male infertility. In the context of the Western world's 'obesity epidemic', this article discusses three main biological mechanisms linking obesity to impaired male reproductive function: hypogonadism, testicular heat stress/hypoxia-induced apoptosis and endocrine disruption by 'obesogens'. Among these, obesity-induced hypogonadism is undoubtedly the most clinically significant and is easily assessed. Rapidly expanding areas of research in this area include leptin modulation of kisspeptins and hypothalamic-pituitary-testicular hormone pathways, and roles of other adipocytokines in male infertility, as well as the impact of exposure to obesogens on the quality of semen.

The obesity epidemic

Obesity has reached epidemic proportions in the United States, with 35.1% of adults being classified as obese. Obesity affects every segment of the US population and continues to increase steadily, especially in children. Obesity increases the risk for many other chronic diseases, including diabetes mellitus, cardiovascular disease, and nonalcoholic fatty liver disease, and decreases overall quality of life. The current US generation may have a shorter life expectancy than their parents if the obesity epidemic is not controlled, and there is no indication that the prevalence of obesity is decreasing. Because of the complexity of obesity, it is likely to be one of the most difficult public health issues our society has faced.

Perinatal taurine depletion increases susceptibility to adult sugar-induced hypertension in rats

This study tests the hypothesis that perinatal taurine depletion produces autonomic nervous system dysregulation and increases arterial pressure in young male rats maintained on a high sugar diet. Sprague-Dawley dams were either taurine depleted (beta-alanine 3% in water) or left untreated from conception to weaning. Their male offspring were fed normal rat chow with or without 5% glucose. At 7-8 weeks of age, the male offspring were either tested in a conscious, unrestrained state or after anesthetia. Body weight was slightly lower in the taurine-depleted rats although their heart or kidneys to body weight ratios were similar. Plasma potassium, blood urea nitrogen, plasma creatinine, hematocrit, fasting blood glucose concentrations and glucose tolerance were all similar. In the taurine-depleted, high glucose group, mean arterial pressure and sympathetic nervous system activity were increased while baroreflex function was impaired. These findings suggest that in this model perinatal taurine depletion causes autonomic nervous system dysfunction that may contribute to dietary high sugar-induced hypertension.

Effects of endocrine disruptors on obesity

Environmental chemicals with hormone-like activity can disrupt the programming of endocrine signalling pathways that are established during perinatal life and result in adverse consequences that may not be apparent until much later in life. Increasing evidence implicates developmental exposure to environmental hormone mimics with a growing list of adverse health consequences in both males and females. Most recently, obesity has been proposed to be yet another adverse health effect of exposure to endocrine disrupting chemicals (EDCs) during critical stages of development. Obesity is quickly becoming a significant human health crisis because it is reaching epidemic proportions worldwide, and is associated with chronic illnesses such as diabetes and cardiovascular disease. In this review, we summarize the literature reporting an association of EDCs and the development of obesity, and further describe an animal model of exposure to diethylstilbestrol that has proven useful in studying mechanisms involved in abnormal programming of various oestrogen target tissues during differentiation. Together, these data suggest new targets (i.e. adipocyte differentiation and mechanisms involved in weight homeostasis) of abnormal programming by EDCs, and provide evidence that support the scientific term 'the developmental origins of adult disease'. The emerging idea of an association of EDCs and obesity expands the focus on obesity from intervention and treatment to include prevention and avoidance of these chemical modifiers.

Proceedings of the Summit on Environmental Challenges to Reproductive Health and Fertility: executive summary

The 2007 Summit on Environmental Challenges to Reproductive Health and Fertility convened scientists, health care professionals, community groups, political representatives, and the media to hear presentations on the impact of environmental contaminants on reproductive health and fertility, and to discuss opportunities to improve health through research, education, communication, and policy. Environmental reproductive health focuses on exposures to environmental contaminants, particularly during critical periods of development, and their potential effects on future reproductive health, including conception, fertility, pregnancy, adolescent development, and adult health. Approximately 87,000 chemical substances are registered for commercial use in the United States, with ubiquitous human exposures to environmental contaminants in air, water, food, and consumer products. Exposures during critical windows of susceptibility may result in adverse effects with lifelong and even intergenerational health impacts. Effects can include impaired development and function of the reproductive tract and permanently altered gene expression, leading to metabolic and hormonal disorders, reduced fertility and fecundity, and illnesses such as testicular, prostate, uterine, and cervical cancers later in life. This executive summary reviews effects of pre- and postnatal exposures on male and female reproductive health, and provides a series of recommendations for advancing the field in the areas of research, policy, health care, and community action.

State of the Art Reviews: Nutrition and Lifestyle for a Healthy Pregnancy

Nutrition and lifestyle factors can maximize health in pregnancy and lower future risk of disease for both mother and fetus. Education can make a big difference for patients in pregnancy outcomes, anxiety, and future health. Pregnancy is a time when attention to proper weight gain can reduce the risk of future obesity, diabetes, hyperlipidemia, and cardiovascular disease. There is mounting evidence that fetal “programming” for future risk of disease begins in utero and varies with nutritional exposures during different times of pregnancy, although the exact mechanisms remain to be elucidated. It is clear that a few simple precautions and enhancements of diet and lifestyle can prevent birth defects and perinatal infections and may reduce future health risks. Exercise in pregnancy is safe and should be encouraged for healthy women.

Proceedings of the Summit on Environmental Challenges to Reproductive Health and Fertility: executive summary

The 2007 Summit on Environmental Challenges to Reproductive Health and Fertility convened scientists, health care professionals, community groups, political representatives, and the media to hear presentations on the impact of environmental contaminants on reproductive health and fertility, and to discuss opportunities to improve health through research, education, communication, and policy. Environmental reproductive health focuses on exposures to environmental contaminants, particularly during critical periods of development, and their potential effects on future reproductive health, including conception, fertility, pregnancy, adolescent development, and adult health. Approximately 87,000 chemical substances are registered for commercial use in the United States, with ubiquitous human exposures to environmental contaminants in air, water, food, and consumer products. Exposures during critical windows of susceptibility may result in adverse effects with lifelong and even intergenerational health impacts. Effects can include impaired development and function of the reproductive tract and permanently altered gene expression, leading to metabolic and hormonal disorders, reduced fertility and fecundity, and illnesses such as testicular, prostate, uterine, and cervical cancers later in life. This executive summary reviews effects of pre- and postnatal exposures on male and female reproductive health, and provides a series of recommendations for advancing the field in the areas of research, policy, health care, and community action.

Developmental exposure to endocrine disruptors and the obesity epidemic

Xenobiotic and dietary compounds with hormone-like activity can disrupt endocrine signaling pathways that play important roles during perinatal differentiation and result in alterations that are not apparent until later in life. Evidence implicates developmental exposure to environmental hormone-mimics with a growing list of health problems. Obesity is currently receiving needed attention since it has potential to overwhelm health systems worldwide with associated illnesses such as diabetes and cardiovascular disease. Here, we review the literature that proposes an association of exposure to environmental endocrine disrupting chemicals with the development of obesity. We describe an animal model of developmental exposure to diethylstilbestrol (DES), a potent perinatal endocrine disruptor with estrogenic activity, to study mechanisms involved in programming an organism for obesity. This experimental animal model provides an example of the growing scientific field termed "the developmental origins of adult disease" and suggests new targets of abnormal programming by endocrine disrupting chemicals.

Impact of diet on the immunological microenvironment of the pregnant uterus and its relationship to allergic disease in the offspring--a review of the recent literature

Medical progress has reduced the mortality from infectious diseases in most countries, but allergic diseases have become more prevalent worldwide over the same period, especially in industrialized countries. This has prompted speculation that modern lifestyles have altered the relationship between heredity and environment so as to promote development of an atopic phenotype when exposure to infection decreases. A healthy uterine microenvironment is known to favor Th2 lymphocyte development. However, some evidence suggests that persistence of the Th2 pattern of immunity directs the developing organism's immune response towards a long-lasting atopic phenotype. Even though the outcome also depends on other factors (such as infection, functional state of the intestinal microflora, and exposure to environmental allergens at times critical to development), it seems that the immune system during the perinatal period is responsive to interventions that are no longer effective in adulthood. We have reviewed the literature accessible through Medline to identify recent advances in the prevention of allergic disease through interventions in the fetal-maternal relationship. Diet seems to have a significant impact on the immunological profile of the pregnant uterus, as well as on the postnatal development of allergic disease in the offspring, as suggested by the effects of probiotic bacteria and by manipulations of the dietary content of polyunsaturated fatty acids and antioxidants. This highlights the need for further studies, in order to define the best intervention methods, the most appropriate time interval and the individuals who will most likely benefit from them.

Role of nutrition in the development of the fetal cardiovascular system

Emerging evidence demonstrates that heart disease may originate during fetal development. This review will focus on the role of maternal nutrition in the development of the fetal cardiovascular system. Emphasis will be placed upon the concept that nutritional inadequacies during gestation may be major programming stimuli that alter fetal cardiac, as well as vascular, physiology and predispose an individual to cardiovascular abnormalities in postnatal life. It is hypothesized that this research area will yield new information, resulting in improved fetal nutrition, growth and development through efficient maternal nutrition before and during pregnancy and will form the basis for nutritional strategies for the primary prevention of cardiovascular disease.