Frank H. Bloomfield

Epigenetic Changes in the Hypothalamic Proopiomelanocortin and Glucocorticoid Receptor Genes in the Ovine Fetus after Periconceptional Undernutrition

Maternal food restriction is associated with the development of obesity in offspring. This study examined how maternal undernutrition in sheep affects the fetal hypothalamic glucocorticoid receptor (GR) and the appetite-regulating neuropeptides, proopiomelanocortin (POMC) and neuropeptide Y, which it regulates. In fetuses from ewes undernourished from -60 to +30 d around conception, there was increased histone H3K9 acetylation (1.63-fold) and marked hypomethylation (62% decrease) of the POMC gene promoter but no change in POMC expression. In the same group, acetylation of histone H3K9 associated with the hypothalamic GR gene was increased 1.60-fold and the GR promoter region was hypomethylated (53% decrease). In addition, there was a 4.7-fold increase in hypothalamic GR expression but no change in methylation of GR gene expression in the anterior pituitary or hippocampus. Interestingly, hypomethylation of both POMC and GR promoter markers in fetal hypothalami was also identified after maternal undernutrition from -60 to 0 d and -2 to +30 d. In comparison, the Oct4 gene, was hypermethylated in both control and underfed groups. Periconceptional undernutrition is therefore associated with marked epigenetic changes in hypothalamic genes. Increase in GR expression in the undernourished group may contribute to fetal programming of a predisposition to obesity, via altered GR regulation of POMC and neuropeptide Y. These epigenetic changes in GR and POMC in the hypothalamus may also predispose the offspring to altered regulation of food intake, energy expenditure, and glucose homeostasis later in life.

Stillbirths: recall to action in high-income countries

Variation in stillbirth rates across high-income countries and large equity gaps within high-income countries persist. If all high-income countries achieved stillbirth rates equal to the best performing countries, 19,439 late gestation (28 weeks or more) stillbirths could have been avoided in 2015. The proportion of unexplained stillbirths is high and can be addressed through improvements in data collection, investigation, and classification, and with a better understanding of causal pathways. Substandard care contributes to 20-30% of all stillbirths and the contribution is even higher for late gestation intrapartum stillbirths. National perinatal mortality audit programmes need to be implemented in all high-income countries. The need to reduce stigma and fatalism related to stillbirth and to improve bereavement care are also clear, persisting priorities for action. In high-income countries, a woman living under adverse socioeconomic circumstances has twice the risk of having a stillborn child when compared to her more advantaged counterparts. Programmes at community and country level need to improve health in disadvantaged families to address these inequities.

Periconceptional Undernutrition of Ewes Impairs Glucose Tolerance in Their Adult Offspring

Maternal undernutrition throughout pregnancy can have long-term effects on the health of adult offspring. Undernutrition around the time of conception alters growth, metabolism, and endocrinology of the sheep fetus, but the impact on offspring after birth is largely unknown. We determined the effect of maternal periconceptional undernutrition in sheep on glucose tolerance in the offspring before and after puberty. Undernourished (UN) ewes were fed individually to maintain weight loss of 10–15% bodyweight from 61 d before until 30 d after mating. Offspring (24 UN, 30 control) underwent an i.v. glucose tolerance test at 4 and 10 mo of age. Glucose tolerance was similar in both groups at 4 mo. Insulin area under the curve increased by 33% between 4 and 10 mo (101 ± 8 versus 154 ± 12 ng · min · mL−1, p < 0.0001). At 10 mo, UN offspring had a 10% greater glucose area under the curve than controls (809 ± 22 versus 712 ± 20 mM · min, p < 0.01), a reduced first phase insulin response (p = 0.003) which was particularly apparent in females and in singletons, and a decreased insulin:glucose ratio (p = 0.01). We conclude that maternal undernutrition around the time of conception results in impaired glucose tolerance in postpubertal offspring.

Epigenetic changes in fetal hypothalamic energy regulating pathways are associated with maternal undernutrition and twinning

Undernutrition during pregnancy is implicated in the programming of offspring for the development of obesity and diabetes. We hypothesized that maternal programming causes epigenetic changes in fetal hypothalamic pathways regulating metabolism. This study used sheep to examine the effect of moderate maternal undernutrition (60 d before to 30 d after mating) and twinning to investigate changes in the key metabolic regulators proopiomelanocortin (POMC) and the glucocorticoid receptor (GR) in fetal hypothalami. Methylation of the fetal hypothalamic POMC promoter was reduced in underfed singleton, fed twin, and underfed twin groups (60, 73, and 63% decrease, respectively). This was associated with reduced DNA methyltransferase activity and altered histone methylation and acetylation. Methylation of the hypothalamic GR promoter was decreased in both twin groups and in maternally underfed singleton fetuses (52, 65, and 55% decrease, respectively). This correlated with changes in histone methylation and acetylation and increased GR mRNA expression in the maternally underfed singleton group. Alterations in GR were hypothalamic specific, with no changes in hippocampi. Unaltered levels of OCT4 promoter methylation indicated gene‐specific effects. In conclusion, twinning and periconceptional undernutrition are associated with epigenetic changes in fetal hypothalamic POMC and GR genes, potentially resulting in altered energy balance regulation in the offspring.—Begum, G., Stevens, A., Smith, E. B., Connor, K., Challis, J. R. G., Bloomfield, F., White, A. Epigenetic changes in fetal hypothalamic energy regulating pathways are associated with maternal undernutrition and twinning. FASEB J. 26, 1694–1703 (2012). www.fasebj.org

Maternal undernutrition programs tissue-specific epigenetic changes in the glucocorticoid receptor in adult offspring

Epidemiological data indicate that an adverse maternal environment during pregnancy predisposes offspring to metabolic syndrome with increased obesity, and type 2 diabetes. The mechanisms are still unclear although epigenetic modifications are implicated and the hypothalamus is a likely target. We hypothesized that maternal undernutrition (UN) around conception in sheep would lead to epigenetic changes in hypothalamic neurons regulating energy balance in the offspring, up to 5 years after the maternal insult. We found striking evidence of decreased glucocorticoid receptor (GR) promoter methylation, decreased histone lysine 27 trimethylation, and increased histone H3 lysine 9 acetylation in hypothalami from male and female adult offspring of UN mothers. These findings are entirely compatible with the increased GR mRNA and protein observed in the hypothalami. The increased GR predicted the decreased hypothalamic proopiomelanocortin expression and increased obesity that we observed in the 5-year-old adult males. The epigenetic and expression changes in GR were specific to the hypothalamus. Hippocampal GR mRNA and protein were decreased in UN offspring, whereas pituitary GR was altered in a sex-specific manner. In peripheral polymorphonuclear leukocytes there were no changes in GR methylation or protein, indicating that this epigenetic analysis did not predict changes in the brain. Overall, these results suggest that moderate changes in maternal nutrition, around the time of conception, signal life-long and tissue-specific epigenetic alterations in a key gene regulating energy balance in the hypothalamus.

Tight Glycemic Control With Insulin in Hyperglycemic Preterm Babies: A Randomized Controlled Trial

OBJECTIVE: The optimal treatment of neonatal hyperglycemia is unclear. The aim of this trial was to determine whether tight glycemic control with insulin improves growth in hyperglycemic preterm infants, without increasing the incidence of hypoglycemia. METHODS: Randomized, controlled, nonblinded trial of 88 infants born at <30 weeks’ gestation or <1500 g who developed hyperglycemia (2 consecutive blood glucose concentrations (BGC) >8.5 mmol/L, 4 hours apart) and were randomly assigned to tight glycemic control with insulin (target BGC 4–6 mmol/L, “tight” group) or standard practice (restrictive guidelines for starting insulin, target BGC 8–10 mmol/L, “control” group). The primary outcome was linear growth rate to 36 weeks’ postmenstrual age. RESULTS: Eighty-eight infants were randomly assigned (tight group n = 43; control group n = 45). Infants in the tight group had a lesser lower leg growth rate (P < .05), but greater head circumference growth (P < .0005) and greater weight gain (P < .001) to 36 weeks’ postmenstrual age than control infants. Tight group infants had lower daily BGC (median [interquartile range] 5.7 [4.8–6.7] vs 6.5 [5.1–8.2] mmol/L, P < .001) and greater incidence of hypoglycemia (BGC <2.6 mmol/L) (25/43 vs 12/45, P < .01) than controls. There were no significant differences in nutritional intake, or in the incidences of mortality or morbidity. CONCLUSIONS: Tight glycemic control with insulin in hyperglycemic preterm infants increases weight gain and head growth, but at the expense of reduced linear growth and increased risk of hypoglycemia. The balance of risks and benefits of insulin treatment in hyperglycemic preterm neonates remains uncertain.

How Is Maternal Nutrition Related to Preterm Birth

The incidence of preterm birth in developed countries is increasing, and in some countries, including the United States, it is almost as high as in developing countries. Demographic changes in women becoming pregnant can account for only a relatively small proportion of the increase. A significant proportion of spontaneous preterm birth continues to be of unknown cause. Experimental data from animal studies suggesting that maternal undernutrition may play a role in spontaneous, noninfectious, preterm birth are supported by observational data in human populations, which support a role for maternal prepregnancy nutritional status in determining gestation length. In addition, intakes or lack of specific nutrients during pregnancy may influence gestation length and thus the risk of preterm birth. As yet, the role of paternal nutrition in contributing to gestation length is unexplored.

Whole animal experiments should be more like human randomized controlled trials.

The quality of reporting of animal studies lags behind that of human randomized controlled trials but a series of additions to the ARRIVE guidelines will help ensure that the standards are comparable.

Increased protein intake decreases postnatal growth faltering in ELBW babies

Objective To determine whether purposely designed nutritional guidelines for extremely low birthweight (ELBW; birth weight <1000 g) babies result in protein intakes that meet international consensus recommendations, and whether this results in improved growth from birth to discharge. Design A prospective cohort study of nutritional intakes and growth in ELBW babies. Setting A tertiary neonatal intensive care unit in New Zealand. Patients 100 ELBW babies who survived for the first month of life, 50 before the introduction of the guideline (Lo Pro) and 50 after (Hi Pro). Intervention Introduction of a nutritional guideline aimed at increasing protein intakes to meet international consensus recommendations. Main outcome measures Weekly protein intakes over the first month of life and growth until discharge. Results Hi Pro babies had significantly higher protein intakes in the first month of life than Lo Pro babies (mean (SD), 3.8 (0.3) vs 3.3 (0.4) g/kg.day, p<0.0001) and a significantly greater growth velocity (GV) over the first 30 days after regaining birth weight (19.5 (5.0) vs 16.2 (5.4) g/kg.day, p<0.002). Hi Pro babies had a significantly lesser Z-score change between birth and discharge than Lo Pro babies for weight (0.0 (1.2) vs −0.9 (1.1), p=0.001), length (−0.8 (0.8) vs −1.2 (1.1), p=0.02) and head circumference (−0.2 (1.1) vs −1.1 (1.6), p<0.001). Conclusions Simple, standardised nutritional guidelines can result in recommended protein intakes for ELBW babies being achieved and result in increased GV. Downward crossing of centiles between birth and discharge, common in ELBW babies, is significantly reduced for weight, length and head circumference.

Survey of the management of neonatal hyperglycaemia in Australasia.

Aim:  Hyperglycaemia is a common problem in very low birthweight (VLBW) preterm neonates and has been associated with an increase in intraventricular haemorrhage and mortality. There are few data to guide clinicians on the best range of blood glucose levels to aim for when treating hyperglycaemic preterm babies with insulin. The aim of this study was to survey all Australasian tertiary neonatal intensive care units for their current practice in the definition and management of neonatal hyperglycaemia to aid in the design of a randomised controlled trial of the effect of tight glycaemic control on long‐term outcome in VLBW babies.