A heretical view: rather than a solely placental protective function, placental 11β hydroxysteroid dehydrogenase 2 also provides substrate for fetal peripheral cortisol synthesis in obese pregnant ewes

Poor maternal nutrition during gestation in sheep alters key hormonal systems involved in energy homeostasis and appetite in the offspring

Disturbances in maternal nutrient availability through increased or decreased abundance of specific or total nutrients during pre-natal development can have negative impacts on offspring growth. These changes are likely mediated, at least in part, by hormonal systems that control energy homeostasis and appetite. Regulation of insulin signaling is critical to ensuring appropriate glucose homeostasis. Poor maternal nutrition during gestation impacts circulating glucose and insulin concentration in both the dam and offspring, reducing circulating insulin and glucose in offspring of restricted-fed dams and increased circulating insulin and glucose in the offspring of over-fed dams. Leptin and ghrelin are key regulators of appetite and feed intake. Offspring of over-fed ewes often exhibit leptin resistance, which may lead to changes in adiposity. Leptin responses in offspring of restricted-fed ewes are not well defined, although restricted-fed ewes themselves exhibit decreased circulating leptin concentrations. Little is known about the effects of poor maternal nutrition on offspring ghrelin. Glucocorticoids and thyroid hormones are required for appropriate fetal development. Poor maternal nutrition during gestation alters the development of the hypothalamic-pituitary-adrenal and thyroid axes in the offspring, although the effects vary according to the type, duration, timing, and severity of the nutritional insult. The relationships between insulin, leptin, ghrelin, glucocorticoids, and thyroid hormones can result in synergistic effects, exacerbating negative outcomes for the offspring. The impacts of poor maternal nutrition are multi-faceted, and the resulting alterations in body composition can continue to impact hormone regulation beyond the initial insult caused by poor maternal nutrition during gestation.

Cardiovascular consequences of maternal obesity throughout the lifespan in first generation sheep

Obesity continues to be a significant global health issue and contributes to a variety of comorbidities and disease states. Importantly, obesity contributes to adverse cardiovascular health outcomes, which is the leading cause of death worldwide. Further, maternal obesity during gestation has been shown to predispose offspring to adverse phenotypic outcomes, specifically cardiovascular outcomes. Therefore, we hypothesized that diet-induced obesity during gestation would result in adverse cardiovascular phenotypes in first-generation offspring that would have functional consequences in juvenile and advanced ages. Multiparous Rambouillet/Columbia cross ewes (F0) were fed a highly palatable, pelleted diet at either 100% (CON), or 150% (OB) of National Research Council recommendations from 60 days prior to conception, until necropsy at d 135 (90%) of gestation (CON: n = 5, OB: n = 6), or through term for lambs (F1: 2.5 mo. old; CON: n = 9, OB: n = 6) and ewes (F1:9 years old; CON: n = 5, OB: n = 8). Paraffin-embedded fetal aorta section staining revealed increased collagen:elastin ratio and greater aortic wall thickness in OBF1 fetuses. Invasive auricular blood pressure recordings revealed elevated systolic blood pressure in OBF1 lambs, but no differences in diastolic pressure. In aged F1 ewes, systolic and diastolic blood pressures were reduced in OBF1 relative to CONF1. Echocardiography revealed no treatment differences in F1 lambs, but F1 ewes show tendencies for increased end systolic volume and decreased stroke volume, and markedly reduced ejection fraction. Therefore, we conclude that maternal obesity programs altered cardiovascular development that results in a hypertensive state in OBF1 lambs. Increased cardiac workload resulting from early life hypertension precedes the failure of the heart to maintain function later in life.

Life Course Impact of Glucocorticoids During Pregnancy on Muscle Development and Function

Maternal stress, such as maternal obesity, can induce severe gestational disease and hormonal disorder which may disrupt fetal organ maturation and further cause endangered early or future health in offspring. During fetal development, glucocorticoids are essential for the maturation of organ systems. For instance, in clinical applications, glucocorticoids are commonly utilized to pregnant women with the risk of preterm delivery to reduce mortality of the newborns. However, exposure of excessive glucocorticoids at embryonic and fetal developmental stages can cause diseases such as cardiovascular disease and muscle atrophy in adulthood. Effects of excessive glucocorticoids on human health are well-recognized and extensively studied. Nonetheless, effects of these hormones on farm animal growth and development, particularly on prenatal muscle development, and postnatal growth, did not attract much attention until the last decade. Here, we provided a short review of the recent progress relating to the effect of glucocorticoids on prenatal skeletal muscle development and postnatal muscle growth as well as heart muscle development and cardiovascular disease during life course.

H19/let-7 axis mediates caffeine exposure during pregnancy induced adrenal dysfunction and its multi-generation inheritance

Previously, we systemically confirmed that prenatal caffeine exposure (PCE) could cause intrauterine growth retardation (IUGR) and adrenal steroid synthesis dysfunction in offspring rats. However, the multi-generation inheritance of adrenal dysfunction and its epigenetic mechanism has not been reported. In this study, the PCE rat model was established, part of the pregnant rats were executed on gestational day 20, while the others were delivered normally and the fetal rats were reared into adulthood. The PCE female rats of filial generation 1 (F1) were mated with wild males to produce F2 offspring, and the same way to produce F3 offspring. All the adult female rats of three generations were sacrificed for the related detection. Results showed that PCE could decrease fetal weight, increase IUGR rate, and elevate serum corticosterone level. Meanwhile, the expression of fetal adrenal GR, DNMT3a/3b, miRNA let-7c increased while those of CTCF, H19, and StAR decreased, and the total methylation rate of the H19 promoter region was enhanced. We used SW-13 cells to clarify the molecular mechanism and found that cortisol-induced in vitro changes of these indexes were consistent with those in vivo. We confirmed that high level of cortisol through activating GR, on the one hand, promoted let-7 expression and inhibited StAR expression; on the other hand, caused high methylation and low expression of H19 by down-regulating CTCF and up-regulating DNMT3a/3b, then enhanced let-7 inhibitory effect on StAR by "molecular sponge" effect. Finally, in vivo experiments showed that the adrenal steroid synthesis function and H19/let-7 axis presented the glucocorticoid-dependent changes in the adult female F1, F2, and F3. In conclusion, PCE can cause female adrenal dysfunction with matrilineal multi-generation inheritance, which is related to the programming alteration of the H19/let-7 axis. This study provides a novel perspective to explain the multi-generation inheritance of fetal-originated disease in IUGR offspring.

Metabolic Disease Programming: From Mitochondria to Epigenetics, Glucocorticoid Signalling and Beyond

Embryonic and foetal development are critical periods of development in which several environmental cues determine health and disease in adulthood. Maternal conditions and an unfavourable intrauterine environment impact foetal development and may programme the offspring for increased predisposition to metabolic diseases and other chronic pathologic conditions throughout adult life. Previously, non-communicable chronic diseases were only associated with genetics and lifestyle. Now the origins of non-communicable chronic diseases are associated with early-life adaptations that produce long-term dysfunction. Early-life environment sets the long-term health and disease risk and can span through multiple generations. Recent research in developmental programming aims at identifying the molecular mechanisms responsible for developmental programming outcomes that impact cellular physiology and trigger adulthood disease. The identification of new therapeutic targets can improve offspring's health management and prevent or overcome adverse consequences of foetal programming. This review summarizes recent biomedical discoveries in the Developmental Origins of Health and Disease (DOHaD) hypothesis and highlight possible developmental programming mechanisms, including prenatal structural defects, metabolic (mitochondrial dysfunction, oxidative stress, protein modification), epigenetic and glucocorticoid signalling-related mechanisms suggesting molecular clues for the causes and consequences of programming of increased susceptibility of offspring to metabolic disease after birth. Identifying mechanisms involved in DOHaD can contribute to early interventions in pregnancy or early childhood, to re-set the metabolic homeostasis and break the chain of subsequent events that could lead to the development of disease.

Maternal obesity in sheep impairs foetal hepatic mitochondrial respiratory chain capacity

BACKGROUND

Changes in the nutritional environment in utero induced by maternal obesity (MO) lead to foetal metabolic dysfunction predisposing offspring to later-life metabolic diseases. Since mitochondria play a crucial role in hepatic metabolism and function, we hypothesized that MO prior to conception and throughout pregnancy programmes foetal sheep liver mitochondrial phenotype.

MATERIAL AND METHODS

Ewes ate an obesogenic diet (150% requirements; MO), or 100% requirements (CTR), from 60 days prior to conception. Foetal livers were removed at 0.9 gestation. We measured foetal liver mitochondrial DNA copy number, activity of superoxide dismutase, cathepsins B and D and selected protein content, total phospholipids and cardiolipin and activity of mitochondrial respiratory chain complexes.

RESULTS

A significant decrease in activities of mitochondrial complexes I, II-III and IV, but not aconitase, was observed in MO. In the antioxidant machinery, there was a significant increase in activity of total superoxide dismutase (SOD) and SOD2 in MO. However, no differences were found regarding autophagy-related protein content (p62, beclin-I, LC3-I, LC3-II and Lamp2A) and cathepsin B and D activities. A 21.5% decrease in total mitochondrial phospholipid was observed in MO.

CONCLUSIONS

The data indicate that MO impairs foetal hepatic mitochondrial oxidative capacity and affects total mitochondrial phospholipid content. In addition, MO affects the regulation of foetal liver redox pathways, indicating metabolic adaptations to the higher foetal lipid environment. Consequences of in utero programming of foetal hepatic metabolism may persist and compromise mitochondrial bioenergetics in later life, and increase susceptibility to metabolic diseases.

A Review of Maternal Nutrition during Pregnancy and Impact on the Offspring through Development: Evidence from Animal Models of Over- and Undernutrition

Similarities in offspring phenotype due to maternal under- or over-nutrition during gestation have been observed in studies conducted at University of Wyoming. In these studies, ewes were either nutrient-restricted (NR) from early to mid-gestation, or fed an obesogenic diet (MO) from preconception through term. Offspring necropsies occurred at mid-gestation, late-gestation, and after parturition. At mid gestation, body weights of NR fetuses were ~30% lighter than controls, whereas MO fetuses were ~30% heavier than those of controls. At birth, lambs born to NR, MO, and control ewes exhibited similar weights. This was a consequence of accelerated fetal growth rates in NR ewes, and reduced fetal growth rates in MO ewes in late gestation, when compared to their respective controls. These fetal growth patterns resulted in remarkably similar effects of increased susceptibility to obesity, cardiovascular disease, and glucose intolerance in offspring programmed mostly during fetal stages of development. These data provide evidence that maternal under- and over-nutrition similarly induce the development of the same cadre of physical and metabolic problems in postnatal life.