Intestinal permeability and peripheral immune cell composition are altered by pregnancy and adiposity at mid- and late-gestation in the mouse.

It is clear that the gastrointestinal tract influences metabolism and immune function. Most studies to date have used male test subjects, with a focus on effects of obesity and dietary challenges. Despite significant physiological maternal adaptations that occur across gestation, relatively few studies have examined pregnancy-related gut function. Moreover, it remains unknown how pregnancy and diet can interact to alter intestinal barrier function. In this study, we investigated the impacts of pregnancy and adiposity on maternal intestinal epithelium morphology, in vivo intestinal permeability, and peripheral blood immunophenotype, using control (CTL) and high-fat (HF) fed non-pregnant female mice and pregnant mice at mid- (embryonic day (E)14.5) and late (E18.5) gestation. We found that small intestine length increased between non-pregnant mice and dams at late-gestation, but ileum villus length, and ileum and colon crypt depths and goblet cell numbers remained similar. Compared to CTL-fed mice, HF-fed mice had reduced small intestine length, ileum crypt depth and villus length. Goblet cell numbers were only consistently reduced in HF-fed non-pregnant mice. Pregnancy increased in vivo gut permeability, with a greater effect at mid- versus late-gestation. Non-pregnant HF-fed mice had greater gut permeability, and permeability was also increased in HF-fed pregnant dams at mid but not late-gestation. The impaired maternal gut barrier in HF-fed dams at mid-gestation coincided with changes in maternal blood and bone marrow immune cell composition, including an expansion of circulating inflammatory Ly6Chigh monocytes. In summary, pregnancy has temporal effects on maternal intestinal structure and barrier function, and on peripheral immunophenotype, which are further modified by HF diet-induced maternal adiposity. Maternal adaptations in pregnancy are thus vulnerable to excess maternal adiposity, which may both affect maternal and child health.

Paternal obesity induces placental hypoxia and sex-specific impairments in placental vascularization and offspring metabolism†.

Paternal obesity predisposes offspring to metabolic dysfunction, but the underlying mechanisms remain unclear. We investigated whether this metabolic dysfunction is associated with changes in placental vascular development and is fueled by endoplasmic reticulum (ER) stress-mediated changes in fetal hepatic development. We also determined whether paternal obesity indirectly affects the in utero environment by disrupting maternal metabolic adaptations to pregnancy. Male mice fed a standard chow or high fat diet (60%kcal fat) for 8-10 weeks were time-mated with female mice to generate pregnancies and offspring. Glucose tolerance was evaluated in dams at mid-gestation (embryonic day (E) 14.5) and late gestation (E18.5). Hypoxia, angiogenesis, endocrine function, macronutrient transport, and ER stress markers were evaluated in E14.5 and E18.5 placentae and/or fetal livers. Maternal glucose tolerance was assessed at E14.5 and E18.5. Metabolic parameters were assessed in offspring at ~60 days of age. Paternal obesity did not alter maternal glucose tolerance but induced placental hypoxia and altered placental angiogenic markers, with the most pronounced effects in female placentae. Paternal obesity increased ER stress-related protein levels (ATF6 and PERK) in the fetal liver and altered hepatic expression of gluconeogenic factors at E18.5. Offspring of obese fathers were glucose intolerant and had impaired whole-body energy metabolism, with more pronounced effects in female offspring. Metabolic deficits in offspring due to paternal obesity may be mediated by sex-specific changes in placental vessel structure and integrity that contribute to placental hypoxia and may lead to poor fetal oxygenation and impairments in fetal metabolic signaling pathways in the liver.

Nutritional adversity, sex and reproduction: 30 years of DOHaD and what have we learned?

It is well established that early life environmental signals, including nutrition, set the stage for long-term health and disease risk - effects that span multiple generations. This relationship begins early, in the periconceptional period and extends into embryonic, fetal and early infant phases of life. Now known as the Developmental Origins of Health and Disease (DOHaD), this concept describes the adaptations that a developing organism makes in response to early life cues, resulting in adjustments in homeostatic systems that may prove maladaptive in postnatal life, leading to an increased risk of chronic disease and/or the inheritance of risk factors across generations. Reproductive maturation and function is similarly influenced by early life events. This should not be surprising, since primordial germ cells are established early in life and thus vulnerable to early life adversity. A multitude of 'modifying' cues inducing developmental adaptations have been identified that result in changes in reproductive development and impairments in reproductive function. Many types of nutritional challenges including caloric restriction, macronutrient excess and micronutrient insufficiencies have been shown to induce early life adaptations that produce long-term reproductive dysfunction. Many pathways have been suggested to underpin these associations, including epigenetic reprogramming of germ cells. While the mechanisms still remain to be fully investigated, it is clear that a lifecourse approach to understanding lifetime reproductive function is necessary. Furthermore, investigations of the impacts of early life adversity must be extended to include the paternal environment, especially in epidemiological and clinical studies of offspring reproductive function.

Fetal Growth Restriction Is Associated With Decreased Number of Ovarian Follicles and Impaired Follicle Growth in Young Adult Guinea Pig Offspring.

BACKGROUND: The mechanisms mediating the impacts of fetal growth restriction (FGR) on follicular development are commonly studied in mouse/rat models, where ovarian development occurs largely during the early postnatal period. These models have shown that FGR is associated with premature follicle loss, early pubertal onset, and accelerated ovarian aging. Whether the same occurs in precocious species is unknown. OBJECTIVE: Since guinea pig follicle development occurs in utero in a manner consistent with human ovarian development, we sought to determine whether FGR had similar impacts on guinea pig ovarian development. METHODS: Dunkin-Hartley guinea pig dams were randomized to receive a control (CON) or a nutrient-restricted diet (FGR) prior to conception until weaning. Offspring ovaries were collected at prepubertal (postnatal day [P] 25) and young adult (P110) time points. RESULTS: Prepubertal offspring exposed to FGR showed little differences in ovarian transcript levels and follicle counts. Young adult FGR offspring, however, showed reductions in the number of transitioning, primary, and antral follicles, as well as corpora lutea. This loss in follicles was associated with reduced insulin-like growth factor receptor and growth differentiation factor-9 messenger RNA levels in FGR P110 offspring compared to CON. CONCLUSION: We demonstrate that FGR in guinea pigs is accompanied by perturbations in signaling pathways essential for proper follicle growth and manifests as reductions in growing follicles in offspring, but these changes do not manifest until postpuberty. These data support the fact that accelerated reproductive maturation/aging is a conserved phenotype that is associated with in utero nutritional adversity.

Maternal nutrient restriction impairs young adult offspring ovarian signaling resulting in reproductive dysfunction and follicle loss.

Reproductive abnormalities are included as health complications in offspring exposed to poor prenatal nutrition. We have previously shown in a rodent model that offspring born to nutrient restriction during pregnancy are born small, enter puberty early, and display characteristics of early ovarian aging as adults. The present study investigated whether key proteins involved in follicle recruitment and growth mediate ovarian follicle loss. Pregnant rats were randomized to a standard diet throughout pregnancy and lactation (CON), or a calorie-restricted (50% of control) diet (UN) during pregnancy. Offspring reproductive phenotype was investigated at postnatal days 4, 27, and 65. Maternal UN resulted in young adult (P65) irregular estrous cyclicity due to persistent estrus, a significant loss of antral follicles, corpora lutea, and an increase in atretic follicles. This decrease in growing follicles in UN offspring appears to be due to increased apoptosis as seen by immunopositive staining of pro-apoptotic factor CASP3 (caspase 3) in ovaries of young adult offspring. UN prepubertal offspring had reduced expression levels of Fshr in antral follicles, which may contribute to a decrease in PI3K/AKT activation evident as a decrease in pAKT immunolocalization in prepubertal antral follicles. Moreover, neonatal ovaries of UN offspring show decreased levels of immunopositive staining for AMHR2 (anti-mullerian hormone receptor 2). Collectively, these data demonstrate that maternal UN during pregnancy impacts ovarian function in offspring as early as P65 and provides a model for understanding the mechanisms driving early life UN-induced follicle loss and reproductive dysfunction.