Maternal high fat-high energy diet alters metabolic factors in the non-human primate fetal heart.

The consumption of high fat-high energy diets (HF-HEDs) continues to rise worldwide and parallels the rise in maternal obesity (MO) that predisposes offspring to cardiometabolic disorders. Although the underlying mechanisms are unclear, thyroid hormones (TH) modulate cardiac maturation in utero. Therefore, we aimed to determine the impact of a high fat-high energy diet (HF-HED) on the hormonal, metabolic and contractility profile of the non-human primate (NHP) fetal heart. At ∼9 months preconception, female baboons (Papio hamadryas) were randomly assigned to either a control diet or HF-HED. At 165 days gestational age (term = 184 days), fetuses were delivered by Caesarean section under anaesthesia, humanely killed, and left ventricular cardiac tissue (Control (n = 6 female, 6 male); HF-HED (n = 6 F, 6 M)) was collected. Maternal HF-HED decreased the concentration of active cardiac TH (i.e. triiodothyronine (T3)), and type 1 iodothyronine deiodinase (DIO1) mRNA expression. Maternal HF-HED decreased the abundance of cardiac markers of insulin-mediated glucose uptake phosphorylated insulin receptor substrate 1 (Ser789) and glucose transporter 4, and increased protein abundance of key oxidative phosphorylation complexes (I, III, IV) and mitochondrial abundance in both sexes. Maternal HF-HED alters cardiac TH status, which may induce early signs of cardiac insulin resistance. This may increase the risk of cardiometabolic disorders in later life in offspring born to these pregnancies. KEY POINTS: Babies born to mothers who consume a high fat-high energy diet (HF-HED) prior to and during pregnancy are predisposed to an increased risk of cardiometabolic disorders across the life course. Maternal HF-HED prior to and during pregnancy decreased thyroid hormone triiodothyronine (T3) concentrations and type 1 iodothyronine deiodinase DIO1 mRNA expression in the non-human primate fetal heart. Maternal HF-HED decreased markers of insulin-dependent glucose uptake, phosphorylated insulin receptor substrate 1 and glucose transporter 4 in the fetal heart. Maternal HF-HED increased mitochondrial abundance and mitochondrial OXPHOS complex I, III and IV in the fetal heart. Fetuses from HF-HED pregnancies are predisposed to cardiometabolic disorders that may be mediated by changes in T3, placing them on a poor lifetime cardiovascular health trajectory.

Maternal tadalafil treatment does not increase uterine artery blood flow or oxygen delivery in the pregnant ewe.

Increasing placental perfusion (PP) could improve outcomes of growth-restricted fetuses. One way of increasing PP may be by using phosphodiesterase (PDE)-5 inhibitors, which induce vasodilatation of vascular beds. We used a combination of clinically relevant magnetic resonance imaging (MRI) techniques to characterize the impact that tadalafil infusion has on maternal, placental and fetal circulations. At 116-117 days' gestational age (dGA; term, 150 days), pregnant ewes (n = 6) underwent fetal catheterization surgery. At 120-123 dGA ewes were anaesthetized and MRI scans were performed during three acquisition windows: a basal state and then ∼15-75 min (TAD 1) and ∼75-135 min (TAD 2) post maternal administration (24 mg; intravenous bolus) of tadalafil. Phase contrast MRI and T2 oximetry were used to measure blood flow and oxygen delivery. Placental diffusion and PP were assessed using the Diffusion-Relaxation Combined Imaging for Detailed Placental Evaluation-'DECIDE' technique. Uterine artery (UtA) blood flow when normalized to maternal left ventricular cardiac output (LVCO) was reduced in both TAD periods. DECIDE imaging found no impact of tadalafil on placental diffusivity or fetoplacental blood volume fraction. Maternal-placental blood volume fraction was increased in the TAD 2 period. Fetal D O 2 ${D_{{{\mathrm{O}}_2}}}$ and V ̇ O 2 ${\dot V_{{{\mathrm{O}}_2}}}$ were not affected by maternal tadalafil administration. Maternal tadalafil administration did not increase UtA blood flow and thus may not be an effective vasodilator at the level of the UtAs. The increased maternal-placental blood volume fraction may indicate local vasodilatation of the maternal intervillous space, which may have compensated for the reduced proportion of UtA D O 2 ${D_{{{\mathrm{O}}_2}}}$ .

Betamethasone improved near-term neonatal lamb lung maturation in experimental maternal asthma.

Maternal asthma is associated with increased rates of neonatal lung disease, and fetuses from asthmatic ewes have fewer surfactant-producing cells and lower surfactant-protein B gene (SFTPB) expression than controls. Antenatal betamethasone increases lung surfactant production in preterm babies, and we therefore tested this therapy in experimental maternal asthma. Ewes were sensitised to house dust mite allergen, and an asthmatic phenotype induced by fortnightly allergen lung challenges; controls received saline. Pregnant asthmatic ewes were randomised to receive antenatal saline (asthma) or 12 mg intramuscular betamethasone (asthma+beta) at 138 and 139 days of gestation (term = 150 days). Lambs were delivered by Caesarean section at 140 days of gestation and ventilated for 45 min before tissue collection. Lung function and structure were similar in control lambs (n = 16, 11 ewes) and lambs from asthma ewes (n = 14, 9 ewes). Dynamic lung compliance was higher in lambs from asthma+beta ewes (n = 12, 8 ewes) compared to those from controls (P = 0.003) or asthma ewes (P = 0.008). Lung expression of surfactant protein genes SFTPA (P = 0.048) and SFTPB (P < 0.001), but not SFTPC (P = 0.177) or SFTPD (P = 0.285), was higher in lambs from asthma+beta than those from asthma ewes. Female lambs had higher tidal volume (P = 0.007), dynamic lung compliance (P < 0.001), and SFTPA (P = 0.037) and SFTPB gene expression (P = 0.030) than males. These data suggest that betamethasone stimulates lung maturation and function of near-term neonates, even in the absence of impairment by maternal asthma.

Placenta-Specific Transcripts Containing Androgen Response Elements Are Altered In Silico by Male Growth Outcomes.

A birthweight centile (BWC) below the 25th is associated with an elevated risk of adverse perinatal outcomes, particularly among males. This male vulnerability may stem from alterations in placenta-specific androgen signalling, a signalling axis that involves the androgen receptor (AR)-mediated regulation of target genes containing androgen response elements (AREs). In this study, we examined global and ARE-specific transcriptomic signatures in term male placentae (≥37 weeks of gestation) across BWC subcategories (<10th, 10th-30th, >30th) using RNA-seq and gene set enrichment analysis. ARE-containing transcripts in placentae with BWCs below the 10th percentile were upregulated compared to those in the 10th-30th and >30th percentiles, which coincided with the enrichment of gene sets related to hypoxia and the suppression of gene sets associated with mitochondrial function. In the absence of ARE-containing transcripts in silico, <10th and 10th-30th BWC subcategory placentae upregulated gene sets involved in vasculature development, immune function, and cell adhesion when compared to those in the >30th BWC subcategory. Collectively, our in silico findings suggest that changes in the expression of ARE-containing transcripts in male placentae may contribute to impaired placental vasculature and therefore result in reduced fetal growth outcomes.

Reduced in utero substrate supply decreases mitochondrial abundance and alters the expression of metabolic signalling molecules in the fetal sheep heart.

Babies born with fetal growth restriction (FGR) are at higher risk of developing cardiometabolic diseases across the life course. The reduction in substrate supply to the developing fetus that causes FGR not only alters cardiac growth and structure but may have deleterious effects on metabolism and function. Using a sheep model of placental restriction to induce FGR, we investigated key cardiac metabolic and functional markers that may be altered in FGR. We also employed phase-contrast magnetic resonance imaging MRI to assess left ventricular cardiac output (LVCO) as a measure of cardiac function. We hypothesized that signalling molecules involved in cardiac fatty acid utilisation and contractility would be impaired by FGR and that this would have a negative impact on LVCO in the late gestation fetus. Key glucose (GLUT4 protein) and fatty acid (FATP, CD36 gene expression) substrate transporters were significantly reduced in the hearts of FGR fetuses. We also found reduced mitochondrial numbers as well as abundance of electron transport chain complexes (complexes II and IV). These data suggest that FGR diminishes metabolic and mitochondrial capacity in the fetal heart; however, alterations were not correlated with fetal LVCO. Overall, these data show that FGR alters fetal cardiac metabolism in late gestation. If sustained ex utero, this altered metabolic profile may contribute to poor cardiac outcomes in FGR-born individuals after birth. KEY POINTS: Around the time of birth, substrate utilisation in the fetal heart switches from carbohydrates to fatty acids. However, the effect of fetal growth restriction (FGR) on this switch, and thus the ability of the fetal heart to effectively metabolise fatty acids, is not fully understood. Using a sheep model of early onset FGR, we observed significant downregulation in mRNA expression of fatty acid receptors CD36 and FABP in the fetal heart. FGR fetuses also had significantly lower cardiac mitochondrial abundance than controls. There was a reduction in abundance of complexes II and IV within the electron transport chain of the FGR fetal heart, suggesting altered ATP production. This indicates reduced fatty acid metabolism and mitochondrial function in the heart of the FGR fetus, which may have detrimental long-term implications and contribute to increased risk of cardiovascular disease later in life.

Let's Talk about Placental Sex, Baby: Understanding Mechanisms That Drive Female- and Male-Specific Fetal Growth and Developmental Outcomes.

It is well understood that sex differences exist between females and males even before they are born. These sex-dependent differences may contribute to altered growth and developmental outcomes for the fetus. Based on our initial observations in the human placenta, we hypothesised that the male prioritises growth pathways in order to maximise growth through to adulthood, thereby ensuring the greatest chance of reproductive success. However, this male-specific "evolutionary advantage" likely contributes to males being less adaptable to shifts in the in-utero environment, which then places them at a greater risk for intrauterine morbidities or mortality. Comparatively, females are more adaptable to changes in the in-utero environment at the cost of growth, which may reduce their risk of poor perinatal outcomes. The mechanisms that drive these sex-specific adaptations to a change in the in-utero environment remain unclear, but an increasing body of evidence within the field of developmental biology would suggest that alterations to placental function, as well as the feto-placental hormonal milieu, is an important contributing factor. Herein, we have addressed the current knowledge regarding sex-specific intrauterine growth differences and have examined how certain pregnancy complications may alter these female- and male-specific adaptations.

Maternal obesity impacts fetal liver androgen signalling in a sex-specific manner.

BACKGROUND: Maternal obesity (MO) increases fetal androgen concentrations, the prevalence of macrosomia, and predisposes offspring to metabolic dysfunction in later life, especially males. These risks may be, in part, the result of increased liver-specific androgen signalling pathway activity in utero. Androgen signalling activity can be suppressed by androgen metabolism via cytochrome P450 (CYP) isoenzymes (CYP2B6, CYP3A) or through inhibition of the full-length androgen receptor (AR-FL) via the antagonistic isoform, AR-45. We hypothesised MO impairs CYP enzyme activity and AR-45 expression in male fetal livers, thereby enhancing activity of androgen signalling pathways. METHODS: Nine months prior to pregnancy, nulliparous female baboons were assigned to either ad libitum control or high fat diet. At 165 day (d) gestation (term, 180 d) fetal liver was collected (n = 6/sex/group). CYP activity was quantified using functional assays; subcellular AR expression was measured using Western blot. RESULTS: CYP2B6 and CYP3A activity, and nuclear expression of AR-45, was reduced in MO males only. Nuclear AR-45 expression was inversely related with fetal body weight of MO males only. CONCLUSIONS: Reduced CYP2B6 and CYP3A activity in conjunction with decreased nuclear AR-45 expression may enhance liver androgen signalling in males from MO pregnancies, thereby increasing the risk of macrosomia, as well as metabolic dysfunction in later life.

Characterisation of ciclesonide metabolism in human placentae across gestation.

INTRODUCTION: Current clinical management of pregnancies at risk of preterm delivery includes maternal antenatal corticosteroid (ACS) treatment. ACS activate the glucocorticoid receptor (GR) in all fetal tissues, maturing the lungs at the cost of impaired brain development, creating a need for novel treatments. The prodrug ciclesonide (CIC) activates the GR only when converted to des-CIC by specific enzymes, including acetylcholinesterase (ACHE) and carboxylesterase 1 and 2 (CES1, CES2). Importantly, the human placenta expresses ACHE and CES, and could potentially produce des-CIC, resulting in systemic fetal exposure and GR activation in all fetal tissues. We therefore investigated CES gene expression and conversion of CIC to des-CIC in human placentae collected during the second trimester (Tri2), and at preterm and term birth. METHODS: Differential expression analysis was performed in Tri2 (n = 27), preterm (n = 34), and term (n = 40) placentae using the DESeq2 R-package. Conversion of CIC to des-CIC was measured in a subset of placenta samples (Tri2 n = 7, preterm n = 26, term n = 20) using functional assays. RESULTS: ACHE mRNA expression was higher in Tri2 male than preterm and term male placentae only, whereas CES1 mRNA expression was higher in Tri2 than preterm or term placentae of both sexes. Conversion of CIC to des-CIC did not differ between gestational ages. DISCUSSION: Conversion of CIC to des-CIC by the human placenta may preclude its use as a novel GR-agonist in threatened preterm birth. In vivo studies are required to confirm the extent to which placental activation occurs after maternal treatment.

Maternal obesogenic diet during pregnancy and its impact on fetal hepatic function in baboons.

OBJECTIVE: Maternal obesity (MO) increases the risk of later-life liver disease in offspring, especially in males. This may be due to impaired cytochrome P450 (CYP) enzyme activity driven by an altered maternal-fetal hormonal milieu. MO increases fetal cortisol concentrations that may increase CYP activity; however, glucocorticoid receptor (GR)-mediated signaling can be modulated by alternative GR isoform expression. We hypothesized that MO induces sex-specific changes in GR isoform expression and localization that contribute to reduced hepatic CYP activity. METHODS: Nonpregnant, nulliparous female baboons were assigned to either an ad libitum control diet or a high-fat, high-energy diet (HF-HED) at 9 months pre pregnancy. At 165 days' gestation (term = 180 days), fetal liver samples were collected (n = 6/sex/group). CYP activity was quantified using functional assays, and GR was measured using quantitative RT-PCR and Western blot. RESULTS: CYP3A activity was reduced in the HF-HED group, whereas CYP2B6 activity was reduced in HF-HED males only. Total GR expression was increased in the HF-HED group. Relative nuclear expression of the antagonistic GR isoform GRß was increased in HF-HED males only. CONCLUSIONS: Reduced CYP activity in HF-HED males may be driven in part by dampened hepatic-specific glucocorticoid signaling via altered GR isoform expression. These findings highlight targetable mechanisms that may reduce later-life sex-specific disease risk.

Characterisation of cytochrome P450 isoenzyme activity in sheep liver and placental microsomes.

INTRODUCTION: Drug metabolism during pregnancy is a complex process that involves maternal, placental and fetal sites of metabolism. Indeed, there is a lack of clarity provided from drug metabolism in human pregnancy due to ethical limitations. Large animal models of human pregnancy provide an opportunity to quantify activity of phase 1 drug metabolism mediated by cytochrome P450 (CYP) enzymes in the maternal, placental, and fetal compartments. Herein, we have validated a comprehensive assay to quantify maternal, placental, and fetal CYP activity. METHODS: Isolated microsomes from sheep maternal liver, placenta, and fetal liver (140d gestation, term = 150d) were incubated with CYP-specific probe drugs to quantify the activity of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A. Inhibition studies were performed to validate specificity of probe drugs. The validated assay was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: CYP1A2, CYP2B6, CYP2C8, CYP2C19, CYP2D6, CYP2E1 and CYP3A were active in maternal liver. In contrast, only CYP1A2, CYP2C8 and CYP2D6 were active in the placenta, whereas CYP2B6, CYP2C8 and CYP2D6 were active in the fetal liver. Of the placental-specific CYPs validated, CYP1A2 increased in type A compared with type D placentomes, whereas CYP2C8 activity increased in type B compared with type A and C. DISCUSSION: This study has established conditions for compartment-specific CYP activity in the sheep maternal-placental-fetal unit using a validated and standardised experimental workflow. Compartment- and placentome type-specific CYP activity are important considerations when examining drug metabolism in the maternal-placental-fetal unit and in determining the impact of pregnancy complications.

Acute resveratrol exposure does not impact hemodynamics of the fetal sheep.

Babies born growth restricted are at an increased risk of both poor short-and long-term outcomes. Current interventions to improve fetal growth are ineffective and do not lower the lifetime risk of poor health status. Maternal resveratrol (RSV) treatment increases uterine artery blood flow, fetal oxygenation, and fetal weight. However, studies suggest that diets high in polyphenols such as RSV may impair fetal hemodynamics. We aimed to characterize the effect of RSV on fetal hemodynamics to further assess its safety as an intervention strategy. Pregnant ewes underwent magnetic resonance imaging (MRI) scans to measure blood flow and oxygenation within the fetal circulation using phase contrast-MRI and T2 oximetry. Blood flow and oxygenation measures were performed in a basal state and then repeated while the fetus was exposed to RSV. Fetal blood pressure and heart rate were not different between states. RSV did not impact fetal oxygen delivery (DO2 ) or consumption (VO2 ). Blood flow and oxygen delivery throughout the major vessels of the fetal circulation were not different between basal and RSV states. As such, acute exposure of the fetus to RSV does not directly impact fetal hemodynamics. This strengthens the rationale for the use of RSV as an intervention strategy against fetal growth restriction.

An ex vivo approach to understanding sex-specific differences in placental androgen signalling in the presence and absence of inflammation.

INTRODUCTION: The mechanisms that contribute to continued male intrauterine growth in response to an adverse maternal environment, such as those brought on by maternal asthma, remain largely undefined but may, in part, be mediated by androgen-mediated signalling. We previously reported the expression of multiple AR protein isoforms in the human placenta and proposed the novel AR-45 isoform to be integral in mediating male-specific androgen-dependent signalling in the presence of maternal asthma. In the current study we have used an ex vivo approach to further understand sex-specific differences in placental androgen signalling in the presence and absence of inflammation using human term villous placental explants. METHODS: Explants were cultured in the presence and absence of 0.1 nM dihydrotestosterone (DHT), 1 µg/ml lipopolysaccharide (LPS), or DHT + LPS for 24hr. Tissue was used for gene expression and subcellular AR protein isoform expression. RESULTS: Cytoplasmic and nuclear AR protein isoforms expression did not vary between culture conditions in either sex. AR-45 activity was upregulated in male placentae cultured in DHT, LPS and DHT + LPS only. There were no changes in the expression of androgen-mediated downstream targets in males in response to culture conditions, but females had significantly reduced IGF1R expression in response to LPS. DISCUSSION: Increased AR-45 activity in the presence of inflammation may drive continued male feto-placental growth via maintained expression of downstream growth targets. Our findings build on previous work suggesting an important role for AR-45 in regulating male-specific adaptations to placental inflammation and underscores the need to further characterise the function of this AR isoform.

Maternal-placental-fetal drug metabolism is altered by late gestation undernutrition in the pregnant ewe.

BACKGROUND: Maternal undernutrition during pregnancy disrupts both fetal growth and development with perturbations to certain physiological processes within the maternal-fetal-placental unit, including metabolic function. However, it is unknown if hypoglycemia during pregnancy alters maternal-fetal-placental drug metabolism as mediated by cytochrome P450 (CYP) enzymes. Despite this, hypoglycemia reduces CYP enzyme activity in non-pregnant animals. We therefore hypothesised that in a sheep model of hypoglycemia induced by late gestation undernutrition (LGUN), maternal-fetal-placental CYP activity would be reduced, and that fetal glucose infusion (LGUN+G) would rescue reduced CYP activity. METHODS: At 115d gestation (term, 150d), ewes were allocated to control (100% metabolic energy requirement (MER); n = 11), LGUN (50% MER; n = 7) or LGUN+G (50% MER + fetal glucose infusion; n = 6) and maintained on their diets until post-mortem. Maternal-fetal-placental CYP activity assays were performed at 131-133d gestation. Microsomes were isolated from placenta and fetal liver collected at 139-142d gestation and incubated with CYP-specific probe drugs. Metabolite concentrations were measured using Liquid Chromatography - tandem mass spectrometry (LC-MS/MS). RESULTS: CYP2C19 and CYP3A were undetectable in placenta or fetal liver, and CYP1A2 was undetectable in the fetal liver. Placental-specific CYP1A2 and CYP2D6 activity and hepatic-specific CYP2D6 activity were unaffected by LGUN. Maternal-fetal-placental CYP1A2 activity was reduced in response to LGUN in the maternal compartment only. CONCLUSIONS: Reduced maternal-fetal-placental CYP1A2 activity, but not placental-specific CYP1A2 activity, may lead to the developing fetus being exposed to increased concentrations of CYP1A2-specific substrates and suggests further consideration of drug dosing is required in instances of late gestation maternal undernutrition.

MRI Characterization of Blood Flow and Oxygen Delivery in the Fetal Sheep whilst Exposed to Sildenafil Citrate.

INTRODUCTION: Newborns exposed to sildenafil citrate (SC) in utero have increased rates of persistent pulmonary hypertension. The mechanism behind this has not yet been fully elucidated. We aimed to utilize a combination of clinically relevant MRI techniques to comprehensively characterize the haemodynamics of the fetal sheep whilst under the influence of SC. We hypothesized that these MRI techniques would detect SC-induced increases in pulmonary blood flow and oxygen delivery prior to birth. METHODS: At 116-117 days gestational age (term, 150 days), pregnant Merino ewes (n = 9) underwent fetal catheterization surgery. MRI scans were performed during a basal state and then repeated during a constant umbilical vein infusion of SC to measure blood flow and oxygenation within the major vessels of the fetal circulation using phase-contrast-MRI and T2 oximetry. RESULTS: Right and left ventricular cardiac outputs were not different between states. Pulmonary blood flow increased during the SC state resulting in elevated pulmonary oxygen delivery. Right to left heart shunting through the foramen ovale was reduced without reducing cerebral oxygen delivery. CONCLUSION: SC induces alterations to pulmonary haemodynamics in utero; a characteristic that if maintained may underlie or act as a precursor towards the elevated rates of poor pulmonary outcomes after birth. These MRI techniques are the first to comprehensively characterize sildenafil's direct impact on the pulmonary vasculature and its indirect detriment to the flow of oxygen-rich blood through the foramen ovale.

A preferential switch between placental GR exon 1 promoter variants in the presence of maternal asthma or inflammation upregulates GRα D isoforms.

INTRODUCTION: The human placenta expresses multiple glucocorticoid receptor (GR) isoforms that may be partially regulated by the untranslated 5' exon 1 GR gene promoter region which consists of 9 different promoters and 13 splice variants. The objective of this study was to determine which GR exon 1 variants are expressed in the human placenta and relate these findings to GR mRNA and protein expression. METHODS: Placental extracts from pregnancies with or without the complication of maternal asthma and trophoblast cells exposed to an inflammatory challenge in vitro were examined using PCR and Western blot to measure GR exon 1 variants, GR splice variant mRNA and GR protein isoforms, respectively. RESULTS: All 9 GR exon 1 variants were detectable in the human placenta and included GR exons 1A, 1B, 1C, 1D, 1E, 1F, 1H, 1I and 1J. In the presence of maternal asthma and a male fetus there was preferential expression of GR exon 1B, 1C, IF and 1J (KW-ANOVA, P < 0.05) which were positively correlated with GRα D3 protein isoform. In female placentae from pregnancies complicated by asthma there was no upregulation of any exon 1 variant (KW-ANOVA, P < 0.05). Exposure of BeWo trophoblast cell line to an inflammatory challenge, lipopolysaccharide, in vitro, resulted in preferential expression of GR exon 1B, 1D, 1E and 1H and associated with GRα-D1 protein upregulation. DISCUSSION: The preferential expression of different GR exon 1 promoters drive the upregulation of GRα D isoforms and contribute to glucocorticoid resistance observed in male placentae of pregnancies complicated by asthma.

Hepatic cytochrome P450 function is reduced by life-long Western diet consumption in guinea pig independent of birth weight.

INTRODUCTION: Non-alcoholic fatty liver disease (NAFLD) is characterised by accumulation of triglycerides and cholesterol within the liver and dysregulation of specific hepatic cytochrome P450 (CYPs) activity. CYPs are involved in the metabolism of endogenous and exogenous chemicals. Hepatic CYP activity is dysregulated in human studies and animal models of a Western diet (WD) or low birth weight (LBW) independently, but the additive effects of LBW and postnatal WD consumption are unknown. As such, the aim of this study was to determine the independent and combined effect of birthweight and postnatal diet on hepatic CYP activity in a guinea pig model. METHODS: LBW was generated via uterine artery ablation at mid gestation (term = 70 days gestation). Normal birthweight (NBW) and LBW pups were allocated either a control diet (CD) or WD at weaning. After 4 months of dietary intervention, guinea pigs were humanely killed, and liver tissue collected for biochemical and functional hepatic CYP activity analyses. RESULTS: Independent of birthweight, functional activity of CYP3A was significantly reduced in female and male WD compared to CD animals (female, P < 0.0001; male, P = 0.004). Likewise, CYP1A2 activity was significantly reduced in male WD compared to CD animals (P = 0.020) but this same reduction was not observed in females. CONCLUSION: Diet, but not birthweight, significantly altered hepatic CYP activity in both sexes, and the effect of diet appeared to be greater in males. These findings may have clinical implications for the management of NAFLD and associated co-morbidities between the sexes.

Identification of placental androgen receptor isoforms in a sheep model of maternal allergic asthma.

Maternal asthma is known to impact intrauterine growth outcomes, which may be mediated, in part, by altered androgen signalling. Our aim was to explore whether the sheep placenta expresses androgen receptor (AR) isoforms and determine if the differential expression of AR protein isoforms is altered by maternal asthma. Four known AR isoforms were detected (AR-FL, AR-v1, AR-v7, and AR-45), and their expression and subcellular distribution was altered in the presence of maternal allergic asthma. These findings underscore the importance for in vivo models of maternal asthma to delineate molecular patterns that may contribute to feto-placental growth and development.

Intrauterine growth restriction alters the activity of drug metabolising enzymes in the maternal-placental-fetal unit.

PURPOSE: Ten percent of pregnancies are affected by intrauterine growth restriction (IUGR), and evidence suggests that affected neonates have reduced activity of hepatic cytochrome P450 (CYP) drug metabolising enzymes. Given that almost all pregnant individuals take medications and additional medications are often required during an IUGR pregnancy, we aimed to determine the impact of IUGR on hepatic CYP activity in sheep fetuses and pregnant ewes. METHODS: Specific probes were used to determine the impact of IUGR on the activity of several CYP isoenzymes (CYP1A2, CYP2C19, CYP2D6 and CYP3A) in sheep fetuses and pregnant ewes. Probes were administered intravenously to the ewe at 132 days (d) gestation (term 150 d), followed by blood sampling from the maternal and fetal circulation over 24 h. Maternal and fetal liver tissue was collected at 139-140 d gestation, from which microsomes were isolated and incubated with probes. Metabolite and maternal plasma cortisol concentrations were measured using Liquid Chromatography - tandem mass spectrometry (LC-MS/MS). RESULTS: Maternal plasma cortisol concentration and maternal hepatic CYP1A2 and CYP3A activity was significantly higher in IUGR pregnancies. Maternal hepatic CYP activity was higher than fetal hepatic CYP activity for all CYPs tested, and there was minimal CYP1A2 or CYP3A activity in the late gestation fetus when assessed using in vitro methods. CONCLUSIONS: The physiological changes to the maternal-placental-fetal unit in an IUGR pregnancy have significant effects on maternal drug metabolism, suggesting changes in medications and/or doses may be required to optimise maternal and fetal health.

The impact of maternal asthma during pregnancy on fetal growth and development: a review.

INTRODUCTION: Asthma is a highly prevalent co-morbidity during pregnancy that can worsen as gestation progresses and is associated with several adverse perinatal outcomes. These adverse outcomes often result from uncontrolled asthma during pregnancy and acute asthma exacerbations that are associated with alterations in placental function and fetal growth. AREAS COVERED: This paper will discuss how maternal asthma in pregnancy affects fetal growth and development which may alter future offspring health. Changes in placental function occur in a sex-specific manner in pregnancies complicated by asthma and result in differences in fetal growth and development which may influence child health. The follow up of children from mothers with asthma suggests they are at greater risk of developing asthma, have alterations in microvascular structure that may contribute to a future risk of cardiovascular disease and epigenetic modifications in immune cell function. The current evidence suggests that appropriately managed asthma during pregnancy results in normal fetal growth and development. EXPERT OPINION: Clinical management of asthma during pregnancy needs significant improvement to prevent adverse outcomes for the fetus. The key to improving maternal and fetal outcomes is through education of health professionals and parents about controlling asthma during pregnancy.

Human placental androgen receptor variants: Potential regulators of male fetal growth.

INTRODUCTION: Numerous studies show that males have increased intrauterine growth compared to females, and that pregnancy complications may further these growth differences, but the regulatory mechanisms underlying these differences remain unknown. We propose that these growth outcomes may be due to sex-specific differences in androgen sensitivity - giving rise to altered growth signalling pathways - mediated by the differential expression of placental androgen receptor (AR) variants. METHODS: Placental protein and mRNA were used to identify AR protein variant levels and AR-downstream target gene expression, and were then analysed against neonatal measurements. Dihydrotestosterone (DHT)-induced AR protein variant expression and downstream growth factors were examined in vitro. RESULTS: Four known AR variants (AR-FL, AR-V1, AR-V7, and AR-45), and three unknown proteins (120, 90 and 55 kDa) immunoreactive to the anti-AR antibody were identified in human placentae. Male placentae from controlled asthmatic pregnancies had increased AR-45 and decreased AR-V1 and AR-V7 nuclear expression. Increased nuclear AR-45 expression was associated with increased insulin-like growth factor 1 (IGF-1), IGF-1 receptor (IGF-1R), and IGF-binding protein 5 (IGFBP-5) mRNA expression and normal male growth. AR-45 mRNA and protein did not change in the presence of uncontrolled maternal asthma and associated with an increase in small for gestational (SGA) male fetuses. In vitro DHT stimulation increased AR-45 protein and IGF-1R and IGFBP-5 mRNA expression. CONCLUSIONS: Collectively, our data shows altered AR protein expression and downstream signalling targets may contribute to sex-specific fetal growth outcomes in response to an adverse environment, and that AR-45 appears central in mediating these changes.