Expression of messenger RNA of insulin-like growth factors (IGFs) and IGF binding proteins (IGFBP1-6) in placenta of normal and diabetic pregnancy

Reduced kidney function and hypertension in adolescents with low birth weight, NHANES 1999-2016

BACKGROUND

Chronic kidney disease (CKD) is a major health problem, and the risk of CKD and hypertension in children born low birth weight (LBW) is under-recognized. We hypothesized that children born with LBW would have a higher prevalence of reduced kidney function and hypertension.

METHODS

Using the National Health and Nutrition Examination Survey (NHANES), we conducted a cross-sectional study to evaluate whether LBW (< 2500 g), very low birth weight (VLBW < 1500 g), and large birth weight (BW) (> 4000 g) were associated with kidney disease using 4 different estimating equations. We used the Counahan-Barratt, updated Schwartz, CKiD-U25, and full age spectrum creatinine-based GFR estimating equations to evaluate associations between a history of LBW/VLBW/large BW and reduced kidney function (eGFR < 90 mL/min/1.73 m2) in children. We also assessed blood pressure (BP) using the old and new pediatric hypertension guidelines.

RESULTS

Our analysis included 6336 children (age 12-15 years) in NHANES representing over 13 million US individuals. Using the updated Schwartz, the prevalence of reduced kidney function was 30.1% (25.2-35.6) for children born with LBW compared to 22.4% (20.5-24.3) in children with normal BW. Equations yielded different estimates of prevalence of reduced kidney function in LBW from 21.5% for Counahan-Barratt to 35.4% for CKiD-U25. Compared to those with normal BW, participants with LBW and VLBW had a 7.2 and 10.3% higher prevalence of elevated BP and a 2.4 and 14.6% higher prevalence of hypertension, respectively.

CONCLUSIONS

Children born with LBW are at higher risk of reduced kidney function and hypertension than previously described. A higher resolution version of the Graphical abstract is available as Supplementary information.

Fetal growth regulation via insulin-like growth factor axis in normal and diabetic pregnancy

OBJECTIVES

Diabetes mellitus (DM) in pregnancy and gestational diabetes remain a considerable cause of pregnancy complications, and fetal macrosomia is among them. Insulin, insulin-like growth factors (IGFs), and components of their signal-transduction axes belong to the predominant growth regulators and are implicated in glucose homeostasis. This study aimed to evaluate the available evidence on the association between the IGF axis and fetal anthropometric parameters in human diabetic pregnancy.

METHODS

PubMed, Medline, Web of Science, and CNKI databases (1981-2021) were searched.

RESULTS

Maternal and cord serum IGF-I levels are suggested to be positively associated with weight and length of neonates born to mothers with type 1 DM. The results concerning IGF-II and IGFBPs in type 1 DM or any of the IGF axis components in type 2 DM remain controversial. The alterations of maternal serum IGFs concentrations throughout diabetic and non-diabetic pregnancy do not appear to be the same. Maternal 1st trimester IGF-I level is positively associated with fetal birth weight in DM.

CONCLUSIONS

Research on the IGF axis should take gestational age of sampling, presence of DM, and insulin administration into account. Maternal 1st trimester IGF-I level might become a predictor for macrosomia development in diabetic pregnancy.

Placental expression of glucose transporters GLUT-1, GLUT-3, GLUT-8 and GLUT-12 in pregnancies complicated by gestational and type 1 diabetes mellitus

Aims/Introduction

The aim of the present study was to evaluate the placental expression of glucose transporters GLUT‐1, GLUT‐3, GLUT‐8 and GLUT‐12 in term pregnancies complicated by well‐controlled gestational (GDM) and type 1 pregestational diabetes mellitus (PGDM).

Materials and Methods

A total of 103 placental samples were obtained from patients diagnosed with GDM (n = 60), PGDM (n = 20) and a non‐diabetic control group (n = 23). Computer‐assisted quantitative morphometry of stained placental sections was performed to determine the expression of selected GLUT proteins.

Results

Immunohistochemical techniques used for the identification of GLUT‐1, GLUT‐3, GLUT‐8 and GLUT‐12 revealed the presence of all glucose transporters in the placental tissue. Morphometric evaluation performed for the vascular density‐matched placental samples demonstrated a significant increase in the expression of GLUT‐1 protein in patients with PGDM as compared to GDM and control groups (P < 0.05). With regard to the expression of the other GLUT isoforms, no statistically significant differences were observed between patients from the diabetic and control populations. Positive correlations between fetal birthweight and the expression of GLUT‐1 protein in the PGDM group (rho = 0.463, P < 0.05) and GLUT‐12 in the control group (rho = 0.481, P < 0.05) were noted.

Conclusions

In term pregnancies complicated by well‐controlled GDM/PGDM, expression of transporters GLUT‐3, GLUT‐8 and GLUT‐12 in the placenta remains unaffected. Increased expression of GLUT‐1 among women with type 1 PGDM might contribute to a higher rate of macrosomic fetuses in this population.

Maternal Diabetes Impairs Insulin and IGF-1 Receptor Expression and Signaling in Human Placenta

BACKGROUND

Maternal high blood glucose during pregnancy increases the risk for both maternal and fetal adverse outcomes. The mechanisms underlying the regulator effects of hyperglycemia on placental development and growth have not been fully illustrated yet. The placenta expresses high amounts of both insulin receptor (IR) and insulin-like growth factor receptor (IGF-1R). It has been reported that the placenta of diabetic women has structural and functional alterations and the insulin/IGF system is likely to play a role in these changes. The aim of the present study was to measure the content of IR and IGF-1R and their phosphorylation in the placenta of women with type 1 diabetes mellitus (T1D) or with gestational diabetes mellitus (GDM) compared to women with normal glucose tolerance (NGT) during pregnancy.

METHODS

Placental tissues were obtained from 80 Caucasian women with a singleton pregnancy. In particular, we collected placenta samples from 20 T1D patients, 20 GDM patients and 40 NGT women during pregnancy. Clinical characteristics and anthropometric measures of all women as well as delivery and newborn characteristics were recorded. Patients were also subdivided on the basis of peripartum glycemia either ≥90 mg/dl or <90 mg/dl, regardless of the diagnosis.

RESULTS

In T1D patients, a higher rate of adverse outcomes was observed. Compared to the GDM women, the T1D group showed significantly higher average capillary blood glucose levels at the third trimester of pregnancy and at peripartum, and higher third-trimester HbA1c values. In both T1D and GDM women, HbA1c values during pregnancy correlated with glucose values in the peripartum period (R-squared 0.14, p=0.02). A positive correlation was observed between phosphorylation of placental IR and the glucose levels during the third trimester of GDM and T1D pregnancy (R-squared 0.21, p=0.003). In the placenta of T1D patients, IGF-1R phosphorylation and IR isoform A (IR-A) expression were significantly increased (p=0.006 and p=0.040, respectively), compared to the NGT women. Moreover, IGF-1R phosphorylation was significantly increased (p<0.0001) in the placenta of patients with peripartum glucose >90 mg/dl, while IR-A expression was increased in those with peripartum blood glucose higher than 120 mg/dl (p=0.046).

CONCLUSIONS

To the best of our knowledge, our study represents the first one in which an increased maternal blood glucose level during pregnancy is associated with an increased IGF-1R phosphorylation and IR-A expression in the placenta. Both these mechanisms can promote an excessive fetal growth.

Relationship between Size of the Foveal Avascular Zone and Carbohydrate Metabolic Disorders during Pregnancy

Aim

To determine whether the area of the foveal avascular zone (FAZ), as a morphological indicator of the microcirculation of the perifoveal capillary network, changes in the carbohydrate metabolism disorders during pregnancy (the gestational age of patients with gestational diabetes mellitus (GDM) and preexisting diabetes (PexD)).

Methods

Ten normal individuals and 41 eyes of 41 patients, 28 with GDM and 13 with PexD, were studied. A 3 × 3 mm area of the FAZ of the superficial capillary plexus layer (SCP) and the deep capillary plexus layer (DCP) was determined by optical coherence tomography angiography (OCTA; RS-3000 Advance, NIDEK). The significance of the correlation between the size of the FAZ and the weeks of pregnancy was determined.

Results

The area of the FAZ of the SCP was 0.38 ± 0.11 mm² (normal eyes), 0.41 ± 0.16 mm² (GDM), and 0.43 ± 0.10 mm² (PexD). The area of the FAZ of the DCP was 0.78 ± 0.23 mm² (normal eyes), 0.69 ± 0.16 mm² (GDM), and 0.79 ± 0.25 mm² (PexD). No significant difference in the FAZ sizes was observed between the groups. The average number of weeks of pregnancy was 24.1 ± 8.2 weeks in the eyes with GDM and 23.3 ± 11.4 weeks in the eyes with PexD (P > 0.05). Significant correlations were found between the size of the FAZ of the SCP and the number of weeks (r = 0.37, P=0.04 for GDM, and r = 0.49, P=0.04 for PexD, Spearman's rank-order correlation coefficient).

Conclusions

For GDM and PexD under established glycemic control, the area of the FAZ is not affected, but vascular changes occurred at the early phase of pregnancy.

Developmental programming of aging trajectory

There is accumulating evidence that aging phenotype and longevity may be developmentally programmed. Main mechanisms linking developmental conditions to later-life health outcomes include persistent changes in epigenetic regulation, (re)programming of major endocrine axes such as growth hormone/insulin-like growth factor axis and hypothalamic-pituitary-adrenal axis and also early-life immune maturation. Recently, evidence has also been generated on the role of telomere biology in developmental programming of aging trajectory. In addition, persisting changes of intestinal microbiota appears to be crucially involved in these processes. In this review, experimental and epidemiological evidence on the role of early-life conditions in programming of aging phenotypes are presented and mechanisms potentially underlying these associations are discussed.

Birth weight predicts aging trajectory: A hypothesis

Increasing evidence suggests that risk for age-related disease and longevity can be programmed early in life. In human populations, convincing evidence has been accumulated indicating that intrauterine growth restriction (IUGR) resulting in low birth weight (<2.5 kg) followed by postnatal catch-up growth is associated with various aspects of metabolic syndrome, type 2 diabetes and cardiovascular disease in adulthood. Fetal macrosomia (birth weight > 4.5 kg), by contrast, is associated with high risk of non-diabetic obesity and cancers in later life. Developmental modification of epigenetic patterns is considered to be a central mechanism in determining such developmentally programmed phenotypes. Growth hormone/insulin-like growth factor (GH/IGF) axis is likely a key driver of these processes. In this review, evidence is discussed that suggests that different aging trajectories can be realized depending on developmentally programmed life-course dynamics of IGF-1. In this hypothetical scenario, IUGR-induced deficit of IGF-1 causes "diabetic" aging trajectory associated with various metabolic disorders in adulthood, while fetal macrosomia-induced excessive levels of IGF-1 lead to "cancerous" aging trajectory. If the above reasoning is correct, then both low and high birth weights are predictors of short life expectancy, while the normal birth weight is a predictor of "normal" aging and maximum longevity.

Human placental growth hormone is increased in maternal serum at 20 weeks of gestation in pregnancies with large-for-gestational-age babies

To investigate the relationship between maternal serum concentrations of placental growth hormone (GH-V), insulin-like growth factor (IGF)-1 and 2, IGF binding proteins (IGFBP)-1 and 3 and birth weight in appropriate-for-gestational-age (AGA), large-for-gestational-age (LGA) and small-for-gestational-age (SGA) cases in a nested case-control study. Maternal serum samples were selected from the Screening for Pregnancy Endpoints (SCOPE) biobank in Auckland, New Zealand. Serum hormone concentrations were determined by ELISA. We found that maternal serum GH-V concentrations at 20 weeks of gestation in LGA pregnancies were significantly higher than in AGA and SGA pregnancies. Maternal GH-V concentrations were positively correlated to birth weights and customized birth weight centiles, while IGFBP-1 concentrations were inversely related to birth weights and customized birth weight centiles. Our findings suggest that maternal serum GH-V and IGFBP-1 concentrations at 20 weeks' gestation are associated with fetal growth.

Insulin-like growth factor axis in pregnancies affected by fetal growth disorders

Background

Insulin-like growth factors 1 and 2 (IGF1 and IGF2) and their binding proteins (IGFBPs) are expressed in the placenta and known to regulate fetal growth. DNA methylation is an epigenetic mechanism which involves addition of methyl group to a cytosine base in the DNA forming a methylated cytosine-phosphate-guanine (CpG) dinucleotide which is known to silence gene expression. This silences gene expression, potentially altering the expression of IGFs and their binding proteins. This study investigates the relationship between DNA methylation of components of the IGF axis in the placenta and disorders in fetal growth. Placental samples were obtained from cord insertions immediately after delivery from appropriate, small (defined as birthweight <10th percentile for the gestation [SGA]) and macrosomic (defined as birthweight > the 90th percentile for the gestation [LGA]) neonates. Placental DNA methylation, mRNA expression and protein levels of components of the IGF axis were determined by pyrosequencing, rtPCR and Western blotting.

Results

In the placenta from small for gestational age (SGA) neonates (n = 16), mRNA and protein levels of IGF1 were lower and of IGFBPs (1, 2, 3, 4 and 7) were higher (p < 0.05) compared to appropriately grown neonates (n = 37). In contrast, in the placenta from large for gestational age (LGA) neonates (n = 20), mRNA and protein levels of IGF1 was not different and those of IGFBPs (1, 2, 3 and 4) were lower (p < 0.05) compared to appropriately grown neonates. Compared to appropriately grown neonates, CpG methylation of the promoter regions of IGF1 was higher in SGA neonates. The CpG methylation of the promoter regions of IGFBP1, IGFBP2, IGFBP3, IGFBP4 and IGFBP7 was lower in the placenta from SGA neonates as compared to appropriately grown neonates, but was unchanged in the placenta from LGA neonates.

Conclusions

Our results suggest that changes in CpG methylation contribute to the changes in gene expression of components of the IGF axis in fetal growth disorders. Differential methylation of the IGF1 gene and its binding proteins is likely to play a role in the pathogenesis of SGA neonates.

Diabetes-associated changes in the fetal insulin/insulin-like growth factor system are organ specific in rats

BACKGROUND

Diabetes in pregnancy affects fetal growth and development. The insulin/insulin-like growth factors (IGF) system comprising insulin, IGF, their receptors, and binding proteins, has been implicated in fetal growth regulation. This study tested the hypothesis that maternal diabetes alters the fetal insulin/IGF system in a tissue-specific manner.

METHODS

Wistar rats were rendered diabetic by neonatal administration of streptozotocin and mated with control rats. At day 21 of gestation, the weights of fetuses, placentas, and fetal organs (heart, lung, liver, stomach, intestine, and pancreas) were determined. Maternal and fetal plasma concentrations of insulin, IGF1, and IGF2 were measured by ELISA, and expression of IGF1, IGF2, IGF1R, IGF2R, IR, IGFBP1, BP2, and BP3 in placenta and fetal organs by qPCR.

RESULTS

The well-known increase in fetal growth in this model of mild diabetes is accompanied by elevated insulin and IGF1 levels and alterations of the insulin/IGF system in the fetus and the placenta. These alterations were organ and gene specific. The insulin/IGF system was generally upregulated, especially in the fetal heart, while it was downregulated in fetal lung.

CONCLUSION

In our model of mild diabetes, the effect of maternal diabetes on fetal weight and fetal insulin/IGF system expression is organ specific with highly sensitive organs such as lung and heart, and organs that were less affected, such as stomach.

Fetal growth factors and fetal nutrition

Optimal fetal growth is important for a healthy pregnancy outcome and also for lifelong health. Fetal growth is largely regulated by fetal nutrition, and mediated via the maternal and fetal glucose/insulin/insulin-like growth factor axes. Fetal nutrition may reflect maternal nutrition, but abnormalities of placental function can also affect fetal growth, as the placenta plays a key intermediary role in nutritional signalling between mother and fetus. Fetal nutrition also impacts on the development of key fetal endocrine systems such as the glucose-insulin and insulin-like growth factor axes. This is likely to contribute to the link between both fetal growth restriction and fetal overgrowth, and increased risks of obesity and impaired glucose tolerance in later life. This review focuses on the associations between maternal and fetal nutrition, fetal growth and later disease risk, with particular emphasis on the role of insulin-like growth factors and the importance of the periconceptional period.

Maternal and fetal placental growth hormone and IGF axis in type 1 diabetic pregnancy

AIM

Placental growth hormone (PGH) is a major growth hormone in pregnancy and acts with Insulin Like Growth Factor I (IGF-I) and Insulin Like Growth Hormone Binding Protein 3 (IGFBP3). The aim of this study was to investigate PGH, IGF-I and IGFBP3 in non-diabetic (ND) compared to Type 1 Diabetic (T1DM) pregnancies.

METHODS

This is a prospective study. Maternal samples were obtained from 25 ND and 25 T1DM mothers at 36 weeks gestation. Cord blood was obtained after delivery. PGH, IGF-I and IGFBP3 were measured using ELISA.

RESULTS

There was no difference in delivery type, gender of infants or birth weight between groups. In T1DM, maternal PGH significantly correlated with ultrasound estimated fetal weight (r = 0.4, p = 0.02), birth weight (r = 0.51, p<0.05) and birth weight centile (r = 0.41, p = 0.03) PGH did not correlate with HbA1c. Maternal IGF-I was lower in T1DM (p = 0.03). Maternal and fetal serum IGFBP3 was higher in T1DM. Maternal third trimester T1DM serum had a significant band at 16 kD on western blot, which was not present in ND.

CONCLUSION

Maternal T1DM PGH correlated with both antenatal fetal weight and birth weight, suggesting a significant role for PGH in growth in diabetic pregnancy. IGFBP3 is significantly increased in maternal and fetal serum in T1DM pregnancies compared to ND controls, which was explained by increased proteolysis in maternal but not fetal serum. These results suggest that the normal PGH-IGF-I-IGFBP3 axis in pregnancy is abnormal in T1DM pregnancies, which are at higher risk of macrosomia.

Consequences of gestational and pregestational diabetes on placental function and birth weight

Maternal diabetes constitutes an unfavorable environment for embryonic and fetoplacental development. Despite current treatments, pregnant women with pregestational diabetes are at increased risk for congenital malformations, materno-fetal complications, placental abnormalities and intrauterine malprogramming. The complications during pregnancy concern the mother (gravidic hypertension and/or preeclampsia, cesarean section) and the fetus (macrosomia or intrauterine growth restriction, shoulder dystocia, hypoglycemia and respiratory distress). The fetoplacental impairment and intrauterine programming of diseases in the offspring’s later life induced by gestational diabetes are similar to those induced by type 1 and type 2 diabetes mellitus. Despite the existence of several developmental and morphological differences in the placenta from rodents and women, there are similarities in the alterations induced by maternal diabetes in the placenta from diabetic patients and diabetic experimental models. From both human and rodent diabetic experimental models, it has been suggested that the placenta is a compromised target that largely suffers the impact of maternal diabetes. Depending on the maternal metabolic and proinflammatory derangements, macrosomia is explained by an excessive availability of nutrients and an increase in fetal insulin release, a phenotype related to the programming of glucose intolerance. The degree of fetal damage and placental dysfunction and the availability and utilisation of fetal substrates can lead to the induction of macrosomia or intrauterine growth restriction. In maternal diabetes, both the maternal environment and the genetic background are important in the complex and multifactorial processes that induce damage to the embryo, the placenta, the fetus and the offspring. Nevertheless, further research is needed to better understand the mechanisms that govern the early embryo development, the induction of congenital anomalies and fetal overgrowth in maternal diabetes.

Cord blood telomere length, telomerase activity and inflammatory markers in pregnancies in women with diabetes or gestational diabetes

AIMS

We tested the hypothesis that diabetes during pregnancy leads to chromosomal DNA damage and telomere attrition in the feto placental unit and cord blood, and provides evidence for intrauterine programming towards a senescent phenotype in the offspring.

METHODS

We obtained cord blood from pregnant women with pregestational Type 1 diabetes (n=26), Type 2 diabetes (n=20) or gestational diabetes (n=71), and control subjects without diabetes (n=45, n=76 and n=81, respectively) matched for maternal and gestational age. We measured cord blood mononuclear cell telomere length, telomerase activity (a reverse transcriptase that limits telomere attrition), and concentrations of insulin, high-sensitivity C-reactive protein (hs-CRP) and soluble intercellular adhesion molecule-1 (sICAM-1).

RESULTS

We found no significant differences between groups in cord blood telomere length in any nucleated cell type, or in hs-CRP or sICAM-1 concentrations, but telomerase activity was higher in cord blood from Type 1 (P<0.05) and gestational diabetes pregnancies (P<0.05), but not in Type 2 diabetes pregnancies. There were no significant relationships between glycaemic control, cord blood telomere length, telomerase activity or inflammatory markers in any group.

CONCLUSIONS

We found no difference in cord blood telomere length in pregnancies of women with diabetes compared with control subjects, but higher cord blood telomerase activity in Type 1 and gestational diabetes. This may reflect upregulated telomere reverse transcriptase in response to in utero oxidative DNA and telomere damage. These observations are relevant to the hypothesis that diabetes during pregnancy leads to in utero preprogramming towards senescence in the offspring.

Growth factor concentrations and their placental mRNA expression are modulated in gestational diabetes mellitus: possible interactions with macrosomia

Background

Gestational diabetes mellitus (GDM) is a form of diabetes that occurs during pregnancy. GDM is a well known risk factor for foetal overgrowth, termed macrosomia which is influenced by maternal hypergycemia and endocrine status through placental circulation. The study was undertaken to investigate the implication of growth factors and their receptors in GDM and macrosomia, and to discuss the role of the materno-foeto-placental axis in the in-utero regulation of foetal growth.

Methods

30 women with GDM and their 30 macrosomic babies (4.75 ± 0.15 kg), and 30 healthy age-matched pregnant women and their 30 newborns (3.50 ± 0.10 kg) were recruited in the present study. Serum concentrations of GH and growth factors, i.e., IGF-I, IGF-BP3, FGF-2, EGF and PDGF-B were determined by ELISA. The expression of mRNA encoding for GH, IGF-I, IGF-BP3, FGF-2, PDGF-B and EGF, and their receptors, i.e., GHR, IGF-IR, FGF-2R, EGFR and PDGFR-β were quantified by using RT-qPCR.

Results

The serum concentrations of IGF-I, IGF-BP3, EGF, FGF-2 and PDGF-B were higher in GDM women and their macrosomic babies as compared to their respective controls. The placental mRNA expression of the growth factors was either upregulated (FGF-2 or PDGF-B) or remained unaltered (IGF-I and EGF) in the placenta of GDM women. The mRNA expression of three growth factor receptors, i.e., IGF-IR, EGFR and PDGFR-β, was upregulated in the placenta of GDM women. Interestingly, serum concentrations of GH were downregulated in the GDM women and their macrosomic offspring. Besides, the expression of mRNAs encoding for GHR was higher, but that encoding for GH was lower, in the placenta of GDM women than control women.

Conclusions

Our results demonstrate that growth factors might be implicated in GDM and, in part, in the pathology of macrosomia via materno-foeto-placental axis.

Insulin and the IGF system in the human placenta of normal and diabetic pregnancies

The insulin/insulin-like growth factor (IGF) system regulates fetal and placental growth and development. In maternal diabetes, components of this system including insulin, IGF1, IGF2 and various IGF-binding proteins are deregulated in the maternal or fetal circulation, or in the placenta. The placenta expresses considerable amounts of insulin and IGF1 receptors at distinct locations on both placental surfaces. This makes the insulin and the IGF1 receptor accessible to fetal and/or maternal insulin, IGF1 and IGF2. Unlike the receptor for IGF1, the insulin receptor undergoes a gestational change in expression site from the trophoblast at the beginning of pregnancy to the endothelium at term. Insulin and IGFs are implicated in the receptor-mediated regulation of placental growth and transport, trophoblast invasion and placental angiogenesis. The dysregulation of the growth factors and their receptors may be involved in placental and fetal changes observed in diabetes, i.e. enhanced placental and fetal growth, placental hypervascularization and higher levels of fetal plasma amino acids.

No loss of genomic imprinting of IGF-II and H19 in placentas of diabetic pregnancies with fetal macrosomia

OBJECTIVES

Fetal macrosomia is a common complication of maternal diabetes mellitus and is associated with substantial morbidity, but the precise cellular and molecular mechanisms that induce fetal macrosomia are not well understood. The imprinted genes IGF-II and H19 are crucial for placental development and fetal growth. The term placentas from diabetic pregnancies express more insulin-like growth factor II (IGF-II) than those from normal pregnancies. Deregulation of their imprinting status is observed in the macrosomia-associated syndrome, the Beckwith-Wiedemann syndrome. The aim of this study was to determine whether loss of imprinting hence biallelic expression was also a hallmark of macrosomia in diabetic pregnancies.

DESIGN AND METHODS

IGF-II and H19 maternal and paternal expressions were studied in placentas from two groups of type 1 diabetic mothers: one with macrosomic babies and the other with babies of normal weight. Maternal or paternal allele specific expressions were defined by using DNA polymorphic markers of the IGF-II and H19 genes. RFLP analysis was performed on PCR products from genomic DNA of the father, the mother and the child, and on RT-PCR products from placental mRNA.

RESULTS

RFLP analysis showed that the IGF-II gene remains paternally expressed and the H19 gene remains maternally expressed in all placentas examined, independently of the birth weight status.

CONCLUSIONS

These results suggest that, in contrast with Beckwith-Wiedemann syndrome-associated macrosomia, loss of imprinting for IGF-II or H19 is not a common feature of diabetic pregnancies associated with macrosomia.

Inverse changes in fetal insulin-like growth factor (IGF)-1 and IGF binding protein-1 in association with higher birth weight in maternal diabetes

OBJECTIVE

The insulin like growth factor (IGF) system plays a key role in regulating fetal growth, is metabolically regulated, and may influence development of increased birth weight in offspring of mothers with diabetes. We examined IGF-1 and IGF binding protein-1 (IGFBP-1) concentrations in cord blood samples from offspring of mothers with gestational and type 2 diabetes.

DESIGN AND PATIENTS

Case-control study of Maori and Pacific Island mothers recruited prospectively at Middlemore Hospital, South Auckland, New Zealand.

MEASUREMENTS

Cord blood (for insulin, IGF-1 and IGFBP-1) was taken from umbilical vein at birth from singleton babies born after 32 weeks of gestation from138 mothers with gestational diabetes (GDM), 39 mothers with type 2 diabetes (T2DM) and 95 control mothers.

RESULTS

Babies born to mothers with both GDM and T2DM had significantly increased birth weight (Z-score birth weight mean +/- SD: GDM 0.94 +/- 1.31, T2DM 0.53 +/- 1.1) compared to controls (Z-score birth weight -0.08 +/- 1.10). IGFBP-1 was significantly reduced in both diabetic groups (median interquartile range: GDM 67(31-137) ng/ml, T2DM 59(29-105) ng/ml, control 114(56-249) ng/ml). Cord IGF-1 was significantly increased in cord blood of infants of mothers with GDM (42.2 +/- 16.3 ng/ml vs. control 34.7 +/- 18.5 ng/ml) but not T2DM (38.7 +/- 17.4 ng/ml). In all offspring, IGF-1 and IGFBP-1 were positively and negatively correlated with birth weight, respectively.

CONCLUSIONS

Maternal diabetes results in inverse changes of circulating fetal IGF-1 and IGFBP-1 at birth. A decrease in circulating IGFBP-1 and to a lesser extent an increase in circulating IGF-1 may present an important mechanism that contributes to increased birth weight in diabetic pregnancies.

Insulin-like growth factor-1 receptor expression in the placentae of diabetic and normal pregnancies

BACKGROUND

Septal hypertrophic cardiomyopathy (sHCM) is a characteristic anomaly of the infant of diabetic mother (IDM). Insulin-like growth factor-1 (IGF-1) has been identified as a mediator of tissue overgrowth and we have previously shown that maternal IGF-1 levels were significantly elevated among neonates with asymmetrical sHCM. IGF-1 does not cross the placenta; it exerts physiologic action through binding to the IGF-1 receptor (IGF-1R). Localisation and expression of IGF-1R in term diabetic pregnancies are largely unclear. We have studied IGF-1R in the placentae of diabetic and normal pregnancies and this receptor expression in association with neonates with sHCM.

METHODS

IGF-1R localization and expression in the placentae of six diabetic pregnancies associated with neonatal sHCM were compared with six each of randomly selected diabetic and normal pregnancies without neonatal sHCM by immunohistochemistry. The staining for IGF-1R in the deciduas, cytotrophoblasts, syncytiotrophoblasts and villous endothelium for these 18 samples were assessed and scored by two pathologists who were blinded to the respective diagnoses.

RESULTS

Placental IGF-1R staining was negative in the villous endothelium for all three groups. IGF-1R staining was present in deciduas, cytotrophoblasts and syncytiotrophoblasts but the staining was weaker in the entire group of infants with sHCM compared to those without sHCM.

CONCLUSIONS

IGF-1R is localized in all cell types of the placenta except in villous endothelium. Weaker placental IGF-1R staining in the placentae of diabetic pregnancies associated with sHCM suggests reduced expression of IGF-1R. This may be a down-regulatory response to elevated maternal IGF with neonatal sHCM outcome.

Exposure to maternal diabetes is associated with altered fetal growth patterns: A hypothesis regarding metabolic allocation to growth under hyperglycemic-hypoxemic conditions

The prevalence of diabetes is rising worldwide, including women who grew poorly in early life, presenting intergenerational health problems for their offspring. It is well documented that fetuses exposed to maternal diabetes during pregnancy experience both macrosomia and poor growth outcomes in birth size. Less is known about the in utero growth patterns that precede these risk factor expressions. Fetal growth patterns and the effects of clinical class and glycemic control were investigated in 37 diabetic pregnant women and their fetuses and compared to 29 nondiabetic, nonsmoking maternal/fetal pairs who were participants in a biweekly longitudinal ultrasound study with measurements of the head, limb, and trunk dimensions. White clinical class of the diabetic women was recorded (A2-FR) and glycosylated hemoglobin levels taken at the time of measurement assessed glycemic control (median 6.9%, interquartile range 5.6-9.2%). No significant difference in fetal weight was found by exposure. The exposed sample had greater abdominal circumferences from 21 weeks (P < or = 0.05) and shorter legs, but greater upper arm and thigh circumferences accompanied increasing glycemia in the second trimester. In the third trimester, exposed fetuses had a smaller slope for the occipital frontal diameter (P = 0.00) and were brachycephalic. They experienced a proximal/distal growth gradient in limb proportionality with higher humerus / femur ratios (P = 0.04) and arms relatively long by comparison with legs (P = 0.02). HbA1c levels above 7.5% accompanied shorter femur length for thigh circumference after 30 gestational weeks of age. Significant effects of diabetic clinical class and glycemic control were identified in growth rate timing. These growth patterns suggest that hypoxemic and hyperglycemic signals cross-talk with their target receptors in a developmentally regulated, hierarchical sequence. The increase in fetal fat often documented with diabetic pregnancy may reflect altered growth at the level of cell differentiation and proximate mechanisms controlling body composition. These data suggest that the maternal-fetal interchange circuit, designed to share and capture resources on the fetal side, may not have had a long evolutionary history of overabundance as a selective force, and modern health problems drive postnatal sequelae that become exacerbated by increasing longevity.

Predictive value of hormone measurements in maternal and fetal complications of pregnancy

Intrauterine tissues (placenta, amnion, chorion, decidua) express hormones and cytokines that play a decisive role in maternal-fetal physiological interactions. The excessive or deficient release of some placental hormones in association with gestational diseases may reflect an abnormal differentiation of the placenta, an impaired fetal metabolism, or an adaptive response of the feto-placental unit to adverse conditions. This review is focused on the applicability of hormone measurements in the risk assessment, early diagnosis, and management of pregnancies complicated by Down's syndrome, fetal growth restriction, preeclampsia, preterm delivery, and diabetes mellitus. Combined hormonal tests or the combination of hormones and ultrasound may achieve reasonable sensitivity, but research continues to simplify the screening programs without sacrificing their accuracy. Only in a few instances is there sufficient evidence to firmly recommend the routine use of hormone tests to predict maternal and fetal complications, but the judicious use of selected tests may enhance the sensitivity of the risk assessment based solely on clinical and ultrasound examination.

Altered nephrogenesis due to maternal diabetes is associated with increased expression of IGF-II/mannose-6-phosphate receptor in the fetal kidney

We have recently demonstrated that the exposure to hyperglycemia in utero impairs nephrogenesis in rat fetuses (Amri K et al., Diabetes 48:2240-2245, 1999). Diabetic pregnancy is commonly associated with alterations in the IGF system in fetal tissues. It has also been shown that both IGF-I and IGF-II are produced within developing metanephros and promote renal organogenesis. Therefore, we investigated the effect of maternal diabetes on IGFs and their receptors in developing fetal rat kidney. Diabetes was induced in pregnant rats by a single injection of streptozotocin on day 0 of gestation. We measured the amounts of IGF and their receptors, both proteins and mRNAs, in the metanephroi of fetuses issued from diabetic subjects and in age-matched fetuses from control subjects (14-20 days of gestation). IGF-II was produced throughout fetal nephrogenesis, whereas IGF-I protein was not detected, suggesting a critical role of IGF-II in kidney development. Fetal exposure to maternal diabetes caused no change in IGF production in the early stages of nephrogenesis. Similarly, the amounts of IGF-I receptor and insulin receptor were not altered. By contrast, there was an increase in production of IGF-II/mannose-6-phosphate receptor throughout nephrogenesis. Because this receptor plays an essential role in regulating the action of IGF-II, the altered nephrogenesis in fetuses exposed to maternal diabetes may be linked to a decrease in IGF-II bioavailability.