Julie A. Owens

Bio: Julie A. Owens is an academic researcher from University of Adelaide. The author has contributed to research in topics: Fetus & Pregnancy. The author has an hindex of 60, co-authored 214 publications receiving 13301 citations. Previous affiliations of Julie A. Owens include University of Melbourne & University of Newcastle.

Chronic high-fat diet in fathers programs β-cell dysfunction in female rat offspring

Abstract: Childhood obesity and diabetes are closely related to these conditions in either parent, but how the father contributes is unclear. A study in rats shows that normal females mated with obese, glucose-intolerant fathers on a high-fat diet produce female offspring who develop glucose intolerance due to impaired insulin secretion and pancreatic function. This is the first report in any species that a father's diet can initiate progression to diabetes in his offspring. The work highlights a novel role for environmentally induced paternal factors in influencing metabolic disease in offspring and in the growing epidemics of obesity and diabetes. Here it is shown that the consumption of a high-fat diet by male rats has an intergenerational effect: it leads to the dysfunction of pancreatic β-cells in female offspring. Relative to controls, these offspring showed an early onset of impaired insulin secretion and glucose tolerance, which worsened with time. The results add to our understanding of the complex genetic and environmental factors that are leading to the global epidemic of obesity and type 2 diabetes. The global prevalence of obesity is increasing across most ages in both sexes. This is contributing to the early emergence of type 2 diabetes and its related epidemic1,2. Having either parent obese is an independent risk factor for childhood obesity3. Although the detrimental impacts of diet-induced maternal obesity on adiposity and metabolism in offspring are well established4, the extent of any contribution of obese fathers is unclear, particularly the role of non-genetic factors in the causal pathway. Here we show that paternal high-fat-diet (HFD) exposure programs β-cell ‘dysfunction’ in rat F1 female offspring. Chronic HFD consumption in Sprague–Dawley fathers induced increased body weight, adiposity, impaired glucose tolerance and insulin sensitivity. Relative to controls, their female offspring had an early onset of impaired insulin secretion and glucose tolerance that worsened with time, and normal adiposity. Paternal HFD altered the expression of 642 pancreatic islet genes in adult female offspring (P < 0.01); genes belonged to 13 functional clusters, including cation and ATP binding, cytoskeleton and intracellular transport. Broader pathway analysis of 2,492 genes differentially expressed (P < 0.05) demonstrated involvement of calcium-, MAPK- and Wnt-signalling pathways, apoptosis and the cell cycle. Hypomethylation of the Il13ra2 gene, which showed the highest fold difference in expression (1.76-fold increase), was demonstrated. This is the first report in mammals of non-genetic, intergenerational transmission of metabolic sequelae of a HFD from father to offspring.

Paternal obesity initiates metabolic disturbances in two generations of mice with incomplete penetrance to the F2 generation and alters the transcriptional profile of testis and sperm microRNA content

Abstract: Obesity is highly prevalent, and its incidence is increasing. The previous study showing a major effect of paternal obesity on metabolic health of offspring is confounded by comorbidity with diabetes. Therefore, we investigated the effect of diet-induced paternal obesity, in the absence of diabetes, on the metabolic health of two resultant generations and the molecular profiles of the testes and sperm. Founder (F0) male C57BL6 mice were fed either a high-fat diet (HFD) or a control diet (CD); n = 10/diet for a period of 10 wk. Testis expression of mRNA/microRNAs was analyzed by microarray and qPCR and sperm microRNA abundance by qPCR. Two subsequent generations were generated by mating F0 and then F1 mice to CD mice, and their metabolic health was investigated. All mice, other than F0 males, were maintained on a CD. HFD feeding induced paternal obesity with a 21% increase in adiposity, but not overt diabetes, and initiated intergenerational transmission of obesity and insulin resistance in two generations of offspring. This distinct phenotypic constellation is either partially or fully transmitted to both female and male F1 offspring and further transmitted through both parental lineages to the F2 generation, with a heightened effect on female F1 offspring (+67% in adiposity) and their F2 sons (+24% in adiposity). Founder male obesity altered the testes expression of 414 mRNAs by microarray and 11 microRNAs by qPCR, concomitant with alterations in sperm microRNA content and a 25% reduction in global methylation of germ cell DNA. Diet-induced paternal obesity modulates sperm microRNA content and germ cell methylation status, which are potential signals that program offspring health and initiate the transmission of obesity and impaired metabolic health to future generations. This study implicates paternal obesity in the transgenerational amplification of obesity and type 2 diabetes in humans.

Antenatal lifestyle advice for women who are overweight or obese: LIMIT randomised trial

Abstract: Objective To determine the effect of antenatal dietary and lifestyle interventions on health outcomes in overweight and obese pregnant women. Design Multicentre randomised trial. We utilised a central telephone randomisation server, with computer generated schedule, balanced variable blocks, and stratification for parity, body mass index (BMI) category, and hospital. Setting Three public maternity hospitals across South Australia. Participants 2212 women with a singleton pregnancy, between 10+0 and 20+0 weeks’ gestation, and BMI ≥25. Interventions 1108 women were randomised to a comprehensive dietary and lifestyle intervention delivered by research staff; 1104 were randomised to standard care and received pregnancy care according to local guidelines, which did not include such information. Main outcome measures Incidence of infants born large for gestational age (birth weight ≥90th centile for gestation and sex). Prespecified secondary outcomes included birth weight >4000 g, hypertension, pre-eclampsia, and gestational diabetes. Analyses used intention to treat principles. Results 2152 women and 2142 liveborn infants were included in the analyses. The risk of the infant being large for gestational age was not significantly different in the two groups (lifestyle advice 203/1075 (19%) v standard care 224/1067 (21%); adjusted relative risk 0.90, 95% confidence interval 0.77 to 1.07; P=0.24). Infants born to women after lifestyle advice were significantly less likely to have birth weight above 4000 g (lifestyle advice 164/1075 (15%) v standard care 201/1067 (19%); 0.82, 0.68 to 0.99; number needed to treat (NNT) 28, 15 to 263; P=0.04). There were no differences in maternal pregnancy and birth outcomes between the two treatment groups. Conclusions For women who were overweight or obese, the antenatal lifestyle advice used in this study did not reduce the risk delivering a baby weighing above the 90th centile for gestational age and sex or improve maternal pregnancy and birth outcomes. Trial registration Australian and New Zealand Clinical Trials Registry (ACTRN12607000161426).

Effect of diet and physical activity based interventions in pregnancy on gestational weight gain and pregnancy outcomes: meta-analysis of individual participant data from randomised trials

Abstract: National Institute for Health Research (NIHR) Health Technology Assessment) programme (No 12/01/50)

Fetal origins of coronary heart disease

Abstract: The fetal origins hypothesis states that fetal undernutrition in middle to late gestation, which leads to disproportionate fetal growth, programmes later coronary heart disease. Animal studies have shown that undernutrition before birth programmes persisting changes in a range of metabolic, physiological, and structural parameters. Studies in humans have shown that men and women whose birth weights were at the lower end of the normal range, who were thin or short at birth, or who were small in relation to placental size have increased rates of coronary heart disease. We are beginning to understand something of the mechanisms underlying these associations. The programming of blood pressure, insulin responses to glucose, cholesterol metabolism, blood coagulation, and hormonal settings are all areas of active research.

Systematic localization of common disease-associated variation in regulatory DNA.

Abstract: Genome-wide association studies have identified many noncoding variants associated with common diseases and traits. We show that these variants are concentrated in regulatory DNA marked by deoxyribonuclease I (DNase I) hypersensitive sites (DHSs). Eighty-eight percent of such DHSs are active during fetal development and are enriched in variants associated with gestational exposure–related phenotypes. We identified distant gene targets for hundreds of variant-containing DHSs that may explain phenotype associations. Disease-associated variants systematically perturb transcription factor recognition sequences, frequently alter allelic chromatin states, and form regulatory networks. We also demonstrated tissue-selective enrichment of more weakly disease-associated variants within DHSs and the de novo identification of pathogenic cell types for Crohn’s disease, multiple sclerosis, and an electrocardiogram trait, without prior knowledge of physiological mechanisms. Our results suggest pervasive involvement of regulatory DNA variation in common human disease and provide pathogenic insights into diverse disorders.