iTRAQ proteomics analysis of placental tissue with gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus is an endocrine and metabolic disorder that appears for the first time during pregnancy and causes varying degrees of short- and/or long-term effects on the mother and child. The etiology of the disease is currently unknown and isobaric tags for relative and absolute quantitation proteomics approach, the present study attempted to identify potential proteins in placental tissues that may be involved in the pathogenesis of GDM and adverse foetal pregnancy outcomes.

METHODS

Pregnant women with GDM hospitalised were selected as the experimental group, and pregnant women with normal glucose metabolism as the control group. The iTRAQ protein quantification technology was used to screen the differentially expressed proteins between the GDM group and the normal control group, and the differentially expressed proteins were analysed by GO, KEGG, PPI, etc., and the key proteins were subsequently verified by western blot.

RESULTS

Based on the proteomics of iTRAQ, we experimented with three different samples of placental tissues from GDM and normal pregnant women, and the total number of identified proteins were 5906, 5959, and 6017, respectively, which were similar in the three different samples, indicating that the results were reliable. Through the Wayne diagram, we found that the total number of proteins coexisting in the three groups was 4475, and 91 differential proteins that could meet the quantification criteria were strictly screened, of which 32 proteins were up-regulated and 59 proteins were down-regulated. By GO enrichment analysis, these differential proteins are widely distributed in extracellular membrane-bounded organelle, mainly in extracellular exosome, followed by intracellular vesicle, extracellular organelle. It not only undertakes protein binding, protein complex binding, macromolecular complex binding, but also involves molecular biological functions such as neutrophil degranulation, multicellular organismal process, developmental process, cellular component organization, secretion, regulated exocytosis. Through the analysis of the KEGG signaling pathway, it is found that these differential proteins are mainly involved in HIF-1 signaling pathway, Glycolysis/Gluconeogenesis, Central carbon metabolism in cancer, AMPK signaling pathway, Proteoglycans in cancer, Protein processing in endoplasmic reticulum, Thyroid cancer, Alcoholism, Glucagon signaling pathway.

DISCUSSION

This preliminary study helps us to understand the changes in the placental proteome of GDM patients, and provides new insights into the pathophysiology of GDM.

Prenatal interventions for fetal growth restriction in animal models: A systematic review

Fetal growth restriction (FGR) in human pregnancy is associated with perinatal mortality, short- and long-term morbidities. No prenatal therapy is currently established despite decades of research. We aimed to review interventions in animal models for prenatal FGR treatment, and to seek the next steps for an effective clinical therapy. We registered our protocol and searched MEDLINE, Embase, and The Cochrane Library with no language restrictions, in accordance with the PRISMA guideline. We included all studies that reported the effects of any prenatal intervention in animal models of induced FGR. From 3257 screened studies, 202 describing 237 interventions were included for the final synthesis. Mice and rats were the most used animals (79%) followed by sheep (16%). Antioxidants (23%), followed by vasodilators (18%), nutrients (14%), and immunomodulators (12%) were the most tested therapy. Two-thirds of studies only reported delivery or immediate neonatal outcomes. Adverse effects were rarely reported (11%). Most studies (73%), independent of the intervention, showed a benefit in fetal survival or birthweight. The risk of bias was high, mostly due to the lack of randomization, allocation concealment, and blinding. Future research should aim to describe both short- and long-term outcomes across various organ systems in well-characterized models. Further efforts must be made to reduce selection, performance, and detection bias.

Sexually dimorphic changes in the endocrine pancreas and skeletal muscle in young adulthood following intra-amniotic IGF-I treatment of growth-restricted fetal sheep

Fetal growth restriction (FGR) is associated with decreased insulin secretory capacity and decreased insulin sensitivity in muscle in adulthood. We investigated whether intra-amniotic IGF-I treatment in late gestation mitigated the adverse effects of FGR on the endocrine pancreas and skeletal muscle at 18 mo of age. Singleton-bearing ewes underwent uterine artery embolization between 103 and 107 days of gestational age, followed by 5 once-weekly intra-amniotic injections of 360-µg IGF-I (FGRI) or saline (FGRS) and were compared with an unmanipulated control group (CON). We measured offspring pancreatic endocrine cell mass and pancreatic and skeletal muscle mRNA expression at 18 mo of age (n = 7-9/sex/group). Total α-cell mass was increased ∼225% in FGRI males versus CON and FGRS males, whereas β-cell mass was not different between groups of either sex. Pancreatic mitochondria-related mRNA expression was increased in FGRS females versus CON (NRF1, MTATP6, UCP2), and FGRS males versus CON (TFAM, NRF1, UCP2) but was largely unchanged in FGRI males versus CON. In skeletal muscle, mitochondria-related mRNA expression was decreased in FGRS females versus CON (PPARGC1A, TFAM, NRF1, UCP2, MTATP6), FGRS males versus CON (NRF1 and UCP2), and FGRI females versus CON (TFAM and UCP2), with only MTATP6 expression decreased in FGRI males versus CON. Although the window during which IGF-I treatment was delivered was limited to the final 5 wk of gestation, IGF-I therapy of FGR altered the endocrine pancreas and skeletal muscle in a sex-specific manner in young adulthood.NEW & NOTEWORTHY Fetal growth restriction (FGR) is associated with compromised metabolic function throughout adulthood. Here, we explored the long-term effects of fetal IGF-I therapy on the adult pancreas and skeletal muscle. This is the first study demonstrating that IGF-I therapy of FGR has sex-specific long-term effects at both the tissue and molecular level on metabolically active tissues in adult sheep.

Effects of intrauterine insulin-like growth factor-1 therapy for fetal growth restriction on adult metabolism and body composition are sex specific

Fetal growth restriction (FGR) is associated with compromised growth and metabolic function throughout life. Intrauterine therapy of FGR with intra-amniotic insulin-like growth factor-1 (IGF1) enhances fetal growth and alters perinatal metabolism and growth in a sex-specific manner, but the adult effects are unknown. We investigated the effects of intra-amniotic IGF1 treatment of FGR on adult growth and body composition, adrenergic sensitivity, and glucose-insulin axis regulation. Placental embolization-induced FGR was treated with four weekly doses of 360 µg intra-amniotic IGF1 (FGRI) or saline (FGRS). Offspring were raised to adulthood (18 mo: FGRI, n = 12 females, 12 males; FGRS, n = 13 females, 10 males) alongside offspring from unembolized and untreated sheep (CON; n = 12 females, 21 males). FGRI females had increased relative lean mass compared with CON but not FGRS (P < 0.05; 70.6 ± 8.2% vs. 61.4 ± 8.2% vs. 67.6 ± 8.2%), decreased abdominal adipose compared with CON and FGRS (P < 0.05; 43.7 ± 1.2% vs. 49.3 ± 0.9% vs. 48.5 ± 1.0%), increased glucose utilization compared with FGRS but not CON (P < 0.05; 9.6 ± 1.0 vs. 6.0 ± 0.9 vs. 7.6 ± 0.9 mg·kg^-1·min^-1), and increased β-hydroxybutyric acid:nonesterified fatty acid ratio in response to adrenaline compared with CON and FGRS (P < 0.05; 3.9 ± 1.4 vs. 1.1 ± 1.4 vs. 1.8 ± 1.4). FGRS males were smaller and lighter compared with CON but not FGRI (P < 0.05; 86.8 ± 6.3 vs. 93.5 ± 6.1 vs. 90.7 ± 6.3 kg), with increased peak glucose concentration (10%) in response to a glucose load but few other differences. These effects of intra-amniotic IGF1 therapy on adult body composition, glucose-insulin axis function, and adrenergic sensitivity could indicate improved metabolic regulation during young adulthood in female FGR sheep.

Postnatal effects of intrauterine treatment of the growth-restricted ovine fetus with intra-amniotic insulin-like growth factor-1

KEY POINTS

Fetal growth restriction increases the risk of fetal and neonatal mortality and morbidity, and contributes to increased risk of chronic disease later in life. Intra-amniotic insulin-like growth factor-1 (IGF1) treatment of the growth-restricted ovine fetus improves fetal growth, but postnatal effects are unknown. Here we report that intra-amniotic IGF1 treatment of the growth-restricted ovine fetus alters size at birth and mechanisms of early postnatal growth in a sex-specific manner. We also show that maternal plasma C-type natriuretic peptide (CNP) products are related to fetal oxygenation and size at birth, and hence may be useful for non-invasive monitoring of fetal growth restriction. Intrauterine IGF1 treatment in late gestation is a potentially clinically relevant intervention that may ameliorate the postnatal complications of fetal growth restriction.

ABSTRACT

Placental insufficiency-mediated fetal growth restriction (FGR) is associated with altered postnatal growth and metabolism, which are, in turn, associated with increased risk of adult disease. Intra-amniotic insulin-like growth factor-1 (IGF1) treatment of ovine FGR increases growth rate in late gestation, but the effects on postnatal growth and metabolism are unknown. We investigated the effects of intra-amniotic IGF1 administration to ovine fetuses with uteroplacental embolisation-induced FGR on phenotypical and physiological characteristics in the 2  weeks after birth. We measured early postnatal growth velocity, amino-terminal propeptide of C-type natriuretic peptide (NTproCNP), body composition, tissue-specific mRNA expression, and milk intake in singleton lambs treated weekly with 360 μg intra-amniotic IGF1 (FGRI; n = 13 females, 19 males) or saline (FGRS; n = 18 females, 12 males) during gestation, and in controls (CON; n = 15 females, 22 males). There was a strong positive correlation between maternal NTproCNP and fetal oxygenation, and size at birth in FGR lambs. FGR lambs were ∼20% lighter at birth and demonstrated accelerated postnatal growth velocity. IGF1 treatment did not alter perinatal mortality, partially abrogated the reduction in newborn size in females, but not males, and reduced accelerated growth in both sexes. IGF1-mediated upregulation of somatotrophic genes in males during the early postnatal period could suggest that treatment effects are associated with delayed axis maturation, whilst treatment outcomes in females may rely on the reprogramming of nutrient-dependent mechanisms of growth. These data suggest that the growth-restricted fetus is responsive to intra-amniotic intervention with IGF1, and that sex-specific somatotrophic effects persist in the early postnatal period.

Intraplacental gene therapy with Ad-IGF-1 corrects naturally occurring rabbit model of intrauterine growth restriction

Intrauterine growth restriction (IUGR) due to placental insufficiency is a leading cause of perinatal complications for which there is no effective prenatal therapy. We have previously demonstrated that intraplacental injection of adenovirus-mediated insulin-like growth factor-1 (Ad-IGF-1) corrects fetal weight in a murine IUGR model induced by mesenteric uterine artery branch ligation. This study investigated the effect of intraplacental Ad-IGF-1 gene therapy in a rabbit model of naturally occurring IUGR (runt) due to placental insufficiency, which is similar to the human IUGR condition with onset in the early third trimester, brain sparing, and a reduction in liver weight. Laparotomy was performed on New Zealand White rabbits on day 21 of 30 days of gestation and litters were divided into five groups: Control (first position)+phosphate-buffered saline (PBS), control+Ad-IGF-1, runt (third position)+PBS, runt+Ad-IGF-1, and runt+Ad-LacZ. The effect of IGF-1 gene therapy on fetal, placental, liver, heart, lung, and musculoskeletal weights of the growth-restricted pups was examined. Protein expression after gene transfer was seen along the maternal-fetal placenta interface (n=12) 48 hr after gene therapy. There was minimal gene transfer detected in the pups or maternal organs. At term, compared with the normally grown first-position control, the runted third-position pups demonstrated significantly lower fetal, placental, liver, lung, and musculoskeletal weights. The fetal, liver, and musculoskeletal weights were restored to normal by intraplacental Ad-IGF-1 gene therapy (p<0.01), with no change in the placental weight. Intraplacental gene therapy is a novel strategy for the treatment of IUGR caused by placental insufficiency that takes advantage of an organ that will be discarded at birth. Development of nonviral IGF-1 gene delivery using placenta-specific promoters can potentially minimize toxicity to the mother and fetus and facilitate clinical translation of this novel therapy.

Differential pathways to adult metabolic dysfunction following poor nutrition at two critical developmental periods in sheep

Epidemiological and experimental studies suggest early nutrition has long-term effects on susceptibility to obesity, cardiovascular and metabolic diseases. Small and large animal models confirm the influence of different windows of sensitivity, from fetal to early postnatal life, on offspring phenotype. We showed previously that undernutrition in sheep either during the first month of gestation or immediately after weaning induces differential, sex-specific changes in adult metabolic and cardiovascular systems. The current study aims to determine metabolic and molecular changes that underlie differences in lipid and glucose metabolism induced by undernutrition during specific developmental periods in male and female sheep. Ewes received 100% (C) or 50% nutritional requirements (U) from 1–31 days gestation, and 100% thereafter. From weaning (12 weeks) to 25 weeks, offspring were then fed either ad libitum (CC, UC) or were undernourished (CU, UU) to reduce body weight to 85% of their individual target. From 25 weeks, all offspring were fed ad libitum. A cohort of late gestation fetuses were studied after receiving either 40% nutritional requirements (1–31 days gestation) or 50% nutritional requirements (104–127 days gestation). Post-weaning undernutrition increased in vivo insulin sensitivity, insulin receptor and glucose transporter 4 expression in muscle, and lowered hepatic methylation at the delta-like homolog 1/maternally expressed gene 3 imprinted cluster in adult females, but not males. Early gestational undernutrition induced lower hepatic expression of gluconeogenic factors in fetuses and reduced in vivo adipose tissue insulin sensitivity in adulthood. In males, undernutrition in early gestation increased adipose tissue lipid handling mechanisms (lipoprotein lipase, glucocorticoid receptor expression) and hepatic methylation within the imprinted control region of insulin-like growth factor 2 receptor in adulthood. Therefore, undernutrition during development induces changes in mechanisms of lipid and glucose metabolism which differ between tissues and sexes dependent on the period of nutritional restriction. Such changes may increase later life obesity and dyslipidaemia risk.

Hormonal and nutritional drivers of intrauterine growth

PURPOSE OF REVIEW

Size at birth is critical in determining life expectancy with both small and large neonates at risk of shortened life spans. This review examines the hormonal and nutritional drivers of intrauterine growth with emphasis on the role of foetal hormones as nutritional signals in utero.

RECENT FINDINGS

Nutrients drive intrauterine growth by providing substrate for tissue accretion, whereas hormones regulate nutrient distribution between foetal oxidative metabolism and mass accumulation. The main hormonal drivers of intrauterine growth are insulin, insulin-like growth factors and thyroid hormones. Together with leptin and cortisol, these hormones control cellular nutrient uptake and the balance between accretion and differentiation in regulating tissue growth. They also act indirectly via the placenta to alter the materno-foetal supply of nutrients and oxygen. By responding to nutrient and oxygen availability, foetal hormones optimize the survival and growth of the foetus with respect to its genetic potential, particularly during adverse conditions. However, changes in the intrauterine growth of individual tissues may alter their function permanently.

SUMMARY

In both normal and compromised pregnancies, intrauterine growth is determined by multiple hormonal and nutritional drivers which interact to produce a specific pattern of intrauterine development with potential lifelong consequences for health.

Expression of genes involved in energy homeostasis in the duodenum and liver of Holstein-Friesian and Jersey cows and their F1 hybrid

Differences in feed intake and production efficiency in lactating Holstein-Friesian (HF), Jersey (JE), and JE × HF (F1) dairy cows have been reported. The liver-gut axis is important in the regulation of energy homeostasis, appetite behaviour, and production efficiency. The objectives of this study were to determine: 1) the effect of dairy cow genotype on the expression profiles of genes involved in energy homeostasis in duodenal and hepatic tissue, and 2) the association between the expression of these genes across both tissues and with economically important production efficiency traits. The expression of 27 candidate genes involved in energy homeostasis, feed intake, and energy storage was measured by qPCR. Duodenal expression of the pro-opiomelanocortin ( POMC), glucagon-like peptide 1 receptor ( GLP1R), and insulin-like growth factor 1 ( IGF1) genes was highest in HF. In contrast, hepatic expression of the leptin receptor ( LEPR), insulin-like growth factor 1 receptor ( IGF1R), protein kinase, AMP-activated, beta 1 ( AMPKB1), and POMC genes was highest in the F1 cross. In the duodenum, positive correlations were observed between mRNA expression of anorectic peptides ( POMC and GLP1R), whereas a negative correlation was detected between orexigenic (ghrelin) and anorectic (peptide YY) gene expression. A negative correlation was observed between duodenal POMC gene expression and both residual feed intake and milk production efficiency traits, while GLP1R gene expression was negatively correlated with milk production efficiency traits. A heterotic effect was observed in hepatic expression of AMKPB1, IGF1R, LEPR, POMC in the F1 genotype, possibly mediating improved feed efficiency in cross-bred cows. In conclusion, key genes involved in energy homeostasis and appetite behaviour are differentially expressed due to cow genotype in a tissue-dependent fashion. POMC and GLP1R are potential candidate genes for the identification of single nucleotide polymorphisms regulating energetic efficiency in the dairy cow, which may be incorporated into future breeding programmes.

Maternal weight gain: a determinant for fetal abdominal circumference in the second trimester

OBJECTIVE

To study the association between maternal weight gain in pregnancy and fetal abdominal circumference in the second trimester.

DESIGN

Prospective cross-sectional study.

SETTING

Low-risk antenatal clinic.

POPULATION

Six hundred and fifty women with low-risk pregnancy.

METHODS

Women with a regular menstrual period (28±4 days) and certain information on the last menstrual period were recruited when they were referred for routine ultrasound scanning. Women with a discrepancy of>14 days between ultrasound and menstrual age were excluded. Maternal weight gain during pregnancy was derived from information in the antenatal chart and the weekly weight gain was calculated. Fetal abdominal circumference measurements were registered in gestational weeks 15-25 and their z-scores, together with the z-scores of maternal weight gain, were used in a linear regression analysis. Main outcome measures. Association between maternal weight gain and fetal abdominal circumference.

RESULTS

Based on the complete data of 515 women we found a mean maternal weight gain during pregnancy of 0.39 kg/week and a positive association between this weight gain and fetal abdominal circumference in the second trimester (r=0.122 (95%CI 0.051-0.194)), with the strongest effect in women with the slowest weight gain (<0.28 kg/week) (r=0.554 (95%CI 0.261-0.846)).

CONCLUSION

Maternal weight gain in pregnancy is related to and may determine fetal abdominal circumference in gestational weeks 15-25, particularly in those women with a slow weight gain.