The IGF system during fetal-placental development of the mouse

Role of increased IGFBP2 in trophoblast cell proliferation and recurrent spontaneous abortion development: A pilot study

Recurrent spontaneous abortion (RSA) is a serious condition that adversely affects women's health. Differentially expressed proteins (DEPs) in plasma of patients experiencing RSA is helpful to find new therapeutic targets and identified with mass spectrometry. In 57 DEPs, 21 were upregulated and 36 were downregulated in RSA. Gene ontology analyses indicated that identified DEPs were associated with cell proliferation, including significantly downregulated insulin-like growth factor binding protein 2 (IGFBP2). Immunohistochemical result using clinical decidual tissues also showed that IGFBP2 expression was significantly decreased in RSA trophoblasts. Cell proliferation assay indicated that IGFBP2 treatment increased the proliferation and mRNA expressions of PCNA and Ki67 in trophoblast cells. Transcriptome sequencing experiments and Kyoto Encyclopedia of Genes and Genomes analyses revealed that gene expression for components in PI3K-Akt pathway in trophoblasts was significantly upregulated following IGFBP2 treatment. To confirm bioinformatics findings, we did cell-based experiments and found that treatment of inhibitors for insulin-like growth factor (IGF)-1 receptor-PI3K-Akt pathway significantly reduced IGFBP2-induced trophoblast cell proliferation and mRNA expressions of PCNA and Ki67. Our findings suggest that IGFBP2 may increase trophoblast proliferation through the PI3K-Akt signaling pathway to affect pregnancy outcomes and that IGFBP2 may be a new target for future research and treatment of RSA.

Fetal Growth Restriction Is Associated with Pregnancy Associated Plasma Protein A and Uterine Artery Doppler in First Trimester

Fetal growth restriction (FGR) is a major cause of stillbirth and poor neurodevelopmental outcomes. The early prediction may be important to establish treatment options and improve neonatal outcomes. The aim of this study was to assess the association of parameters used in first-trimester screening, uterine artery Doppler pulsatility index and the development of FGR. In this retrospective cohort study, 1930 singleton pregnancies prenatally diagnosed with an estimated fetal weight under the third percentile were included. All women underwent first-trimester screening assessing maternal serum pregnancy-associated plasma protein A (PAPP-A), free beta-human chorionic gonadotrophin levels, fetal nuchal translucency and uterine artery Doppler pulsatility index (PI). We constructed a Receiver Operating Characteristics curve to calculate the sensitivity and specificity of early diagnosis of FGR. In pregnancies with FGR, PAPP-A was significantly lower, and uterine artery Doppler pulsatility index was significantly higher compared with the normal birth weight group (0.79 ± 0.38 vs. 1.15 ± 0.59, p < 0.001 and 1.82 ± 0.7 vs. 1.55 ± 0.47, p = 0.01). Multivariate logistic regression analyses demonstrated that PAPP-A levels and uterine artery Doppler pulsatility index were significantly associated with FGR (p = 0.009 and p = 0.01, respectively). To conclude, these two parameters can predict FGR < 3rd percentile.

First trimester PAPP-A serum levels and long-term metabolic outcome of mothers and their offspring

Low maternal serum levels of pregnancy associated plasma protein A (PAPP-A) are known to be associated with the development of pregnancy-related complications like small for gestational age infants, intrauterine fetal demise, gestational diabetes and preeclampsia. The study aims to find possible long-term correlations with the development of metabolic and cardiovascular complications in the mothers and their progeny in later life. This is a retrospective cohort study conducted on consecutive unselected women screened for chromosomal anomalies in the first trimester of pregnancy between 2004 and 2010. PAPP-A values as well as clinical data collected at childbirth were considered. A maternal and neonatal follow-up was performed through a telephone interview with the mother during 2015. The body-mass-index and the presence of cardiovascular diseases, dyslipidaemia and diabetes mellitus were evaluated. The analysis included 988 patients. The median time of follow-up was 7 years (IQR 6-9). Lower first trimester maternal blood PAPP-A quartiles were associated with small stature of the offspring (z-score 1st-2nd quartile 0.37 IQR -0.42 and 1.17 vs 3rd-4th quartile 0.67 IQR -0.17 and 1.36, p < 0.05). Furthermore, low first trimester PAPP-A in pregnancy without other gestations following the index one, in Kaplan-Meier analysis was associated to a significant increase of hypoglycemic agents use at 7 and 10 years (respectively 1.12% CI.95 0-2.38% and 5.45% CI.95 0-10.82%) compared to the control group of high first trimester PAPP-A values (0% CI.95 0-0%) (p < 0.05). Low PAPP-A serum levels in the first trimester of pregnancy are associated with short stature in offspring and de-novo development of maternal diabetes mellitus in later life.

IGFBP2: integrative hub of developmental and oncogenic signaling network

Insulin-like growth factor (IGF) binding protein 2 (IGFBP2) was discovered and identified as an IGF system regulator, controlling the distribution, function, and activity of IGFs in the pericellular space. IGFBP2 is a developmentally regulated gene that is highly expressed in embryonic and fetal tissues and markedly decreases after birth. Studies over the last decades have shown that in solid tumors, IGFBP2 is upregulated and promotes several key oncogenic processes, such as epithelial-to-mesenchymal transition, cellular migration, invasion, angiogenesis, stemness, transcriptional activation, and epigenetic programming via signaling that is often independent of IGFs. Growing evidence indicates that aberrant expression of IGFBP2 in cancer acts as a hub of an oncogenic network, integrating multiple cancer signaling pathways and serving as a potential therapeutic target for cancer treatment.

The utility of pregnancy associated plasma protein-A MoM values in prediction of term respiratory distress syndrome

This study aimed to investigate if the pregnancy associated plasma Protein-A (PAPP-A) multiples of median (MoM) levels could be used as a marker for the early prediction of RDS. The present study was designed with data gathered from 1773 patients who were referred to our institution for first trimester fetal chromosomal anomaly screening. First trimester PAPP-A MoM values and postnatal RDS occurrences in these pregnancies were retrospectively analysed. Of the 1773 neonates that were included in the study, 28 were delivered at or beyond 37 weeks, and 42 were delivered less than 37 weeks of gestation. In the group of neonates at or beyond 37 weeks, the cut-off value for RDS prediction was determined as 1.02. For this cut-off value, sensitivity was 72.41% and specificity was 91.84%. The area under curve (AUC) was determined to be statistically significant (p < .01). In conclusion, it was determined that in neonates that were delivered at or beyond 37 weeks of gestation, RDS occurrence could be predicted at a significant rate by utilising PAPP-A MoM values.IMPACT STATEMENTWhat is already known on this subject? Respiratory distress syndrome (RDS) is one of the major global healthcare problems, and continues to effect newborns despite the improvements in diagnosis and treatments of the disease. Studies have shown that pregnancy associated plasma protein-A (PAPP-A) has a critical role in cellular proliferation and differentiation, and it is closely associated with many physiological and pathological processes via regulation of local insulin like growth factor (IGF) concentrations. In majority of the past studies in the literature regarding PAPP-A values in pregnancies, the association between low values of PAPP-A MoM and maternal-fetal complications were investigated.What do the results of this study add? This study retrospectively examines the PAPP-A MoM levels and the occurence of RDS. In neonates that were delivered at or beyond 37 weeks of gestation, RDS occurrence could be predicted at a significant rate by utilising PAPP-A MoM values which was measured at the first trimester fetal anomaly screening test.What are the implications of these findings for clinical practice and/or further research? In the light of these findings, in order to reduce RDS related neonatal morbidity and mortality, pregnancies with PAPP-A MoM values greater than 1.02 at the first trimester fetal anomaly screening should be more closely followed up and a higher rate of suspicion should be kept for RDS occurrence.

Regulating needs: Exploring the role of insulin-like growth factor-2 signalling in materno-fetal resource allocation

During pregnancy, the fetus requires nutrients supplied by the mother to grow and develop. However, the mother also requires sufficient resources to support the pregnancy, as well as, to maintain her health. Failure to regulate resource allocation between the mother and fetus can lead to pregnancy complications with immediate and life-long consequences for maternal and offspring health. This review explores the role of insulin-like growth factor (IGF)-2 in regulating materno-fetal resource allocation, particularly via its regulation of placental development and function.

Predicting autism at birth

The amounts of at least three biochemical factors are more often abnormal in autistic people than neurologically normal ones. They include insulin-like growth factor, anti-myelin basic protein, and serotonin. This may explain why processes initiated in utero which hinder normal neurogenesis, especially myelination, continue after delivery. Quantitation of these parameters may make possible the calculation of an autism index, anticipating at birth which children will ultimately develop overt autism.

Low PAPP-A in the first trimester is associated with reduced fetal growth rate prior to gestational week 20

OBJECTIVE

To evaluate the association between maternal pregnancy-associated plasma protein-A (PAPP-A) and fetal growth from the first to the second trimester.

METHODS

A prospective cohort study including 8347 pregnant women attending prenatal care at Aarhus University Hospital were conducted. PAPP-A was measured during 8 to 14 gestational weeks. Fetal growth between the two scans in the first and second trimesters was estimated by (GA(20)- GA(12))/Days(calendar), where GA(12) reflects gestational age in days calculated from crown-rump length at a 12-week scan, GA(20) reflects gestational age in days calculated from biparietal diameter at a 20-week scan, and Days(calendar) reflects the number of calendar days between the two scans.

RESULTS

Fetal growth rate from the first to the second trimester was correlated with PAPP-A, with a regression coefficient of 0.009 (95% CI, 0.007-0.012, P < 0.001). PAPP-A below 0.30 MoM was associated with a fetal growth rate below the tenth centile, with an adjusted OR of 2.05 (95% CI, 1.24-3.38).

CONCLUSION

Low levels of PAPP-A are associated not only with low birth weight at term but also with slower fetal growth prior to 20 weeks of gestation.

Prediction of pre-eclampsia by uterine artery Doppler ultrasonography and maternal serum pregnancy-associated plasma protein-A, free beta-human chorionic gonadotropin, activin A and inhibin A at 22 + 0 to 24 + 6 weeks' gestation

OBJECTIVE

To investigate the potential value of combining uterine artery Doppler ultrasonography with the measurement of maternal serum pregnancy-associated plasma protein-A (PAPP-A), free beta-human chorionic gonadotropin (beta-hCG), activin A and inhibin A at 22 + 0 to 24 + 6 weeks' gestation, in the prediction of pregnancies that subsequently develop pre-eclampsia.

METHODS

The maternal serum PAPP-A, free beta-hCG, activin A and inhibin A concentrations at 22 + 0 to 24 + 6 weeks' gestation were measured in samples obtained from women with singleton pregnancies who participated in a screening study for pre-eclampsia by transvaginal color flow Doppler measurement of the uterine artery pulsatility index (PI). A search was made of the database to identify those who subsequently developed pre-eclampsia (n = 24) and a group of controls with normal outcome (n = 144). Regression analysis was performed to establish any relationship between the biochemical markers themselves and between the biochemical markers and uterine artery mean PI. A multivariate Gaussian model combining various biochemical markers with uterine artery mean PI was developed using standard statistical modeling techniques and the performance of such models in discriminating cases with pre-eclampsia was evaluated by receiver-operating characteristics curve (ROC) analysis.

RESULTS

In the pre-eclampsia group, compared to the controls, the uterine artery mean PI and the maternal serum levels of PAPP-A, free beta-hCG, activin A and inhibin A were significantly increased. The predicted detection rates of pre-eclampsia, for a false positive rate of 5%, was 50% by uterine artery mean PI, 5% by PAPP-A, 10% by free beta-hCG, 35% by inhibin A and 44% by activin A. Screening by a combination of uterine artery mean PI and maternal serum activin A and inhibin A could detect 75% and 92% of patients who subsequently developed pre-eclampsia, for false positive rates of 5% and 10%, respectively.

CONCLUSION

Screening for pre-eclampsia by uterine artery PI at 22 + 0 to 24 + 6 weeks' gestation can be improved by measurement of activin A and inhibin A levels.

Long-lasting in vitro hematopoiesis derived from primate embryonic stem cells

OBJECTIVE

Induction of hematopoietic cells from human embryonic stem (ES) cells has been reported recently. However, before cells derived from human ES cells can be used in the clinic, preclinical studies using these cells in experimental primates will be necessary. Therefore, we attempted to establish a method to induce hematopoietic cells robustly and abundantly from primate ES cells.

METHODS

A primate ES cell line, CMK-6, derived from the cynomolgus monkey was used in this study. We adapted a method to induce hematopoiesis from CMK-6 cells on feeder cells, and tested the effectiveness of three kinds of feeder cell lines (OP9, C2C12, and C3H10T1/2). In addition, we tested the effect of vascular endothelial growth factor (VEGF) and insulin-like growth factor-II (IGF-II) on hematopoiesis induction from CMK-6 cells.

RESULTS

VEGF and IGF-II showed an extremely strong synergistic effect to induce hematopoiesis from CMK-6 cells. C3H10T1/2 cells proved to be very useful for the induction of hematopoiesis from CMK-6 cells, and the production of blood cells on C3H10T1/2 cells has been maintained as long as 5 months. During this long period, ES cell derivatives continuously produced mature blood cells, including terminally differentiated cells.

CONCLUSION

We have developed an original method to produce enriched blood cells abundantly from primate ES cells for an extremely long period. This method may represent a good in vitro model for studying primate hematopoiesis and related diseases. Furthermore, our method may be useful for preclinical studies of transfusion therapy using blood cells derived from ES cells in experimental primate systems.

Refinement of cytokine use in the in vitro expansion of erythroid cells

Blood transfusion is indispensable for many clinical applications. However, the supply of transfusable material is insufficient in many countries. Human cord blood contains many hematopoietic stem and progenitor cells, providing a promising resource for the production of transfusable material in vitro. In this study, we have refined a protocol to produce abundant red blood cells (RBC) from human cord blood in an in vitro culture system. We found that erythropoietin and interleukin-3 were most effective when they were added to the culture medium sequentially rather than simultaneously. Although insulin-like growth factor-I (IGF-1) has been reported to function as a positive regulator of RBC production in some in vitro culture systems, we found that IGF-1 had a negative effect upon RBC production. However, IGF-II appeared to function as a positive regulator of RBC production. Finally, stem cell factor functioned to both expand and accelerate the differentiation of immature erythroid cells.

Prediction of pregnancy complications by first-trimester maternal serum PAPP-A and free beta-hCG and with second-trimester uterine artery Doppler

BACKGROUND

Previous studies have shown an association between low first trimester maternal serum free beta-hCG and PAPP-A and subsequent development of pregnancy complications. Similarly, uterine artery Doppler in the late second trimester has shown that high impedance to flow is associated with increased risk for preeclampsia and fetal growth restriction. The objective of this study is to determine whether there is an association between the maternal serum concentration of PAPP-A and free beta-hCG at 11-13(+6) weeks with the uterine artery pulsatility index (PI) at 22-24 weeks, and secondly, to compare the screening characteristics of the two methods in the prediction of adverse pregnancy outcome.

METHODS

Maternal serum PAPP-A and free beta-hCG at 11-13(+6) weeks and uterine artery PI at 22-24 weeks were measured in 4390 women with singleton pregnancies. Pregnancies with chromosomal defects or fetal anomalies were excluded. The biochemical and Doppler measurements were compared between those with normal outcome and those resulting in spontaneous preterm delivery, pre-eclampsia and fetal growth restriction (FGR). Detection rates using a combination of the biochemical and Doppler measurements were investigated.

RESULTS

In the pregnancies resulting in pre-eclampsia (n = 64) and FGR (n = 172), the median PAPP-A was lower (0.844 and 0.813 MoM), the median uterine artery mean PI was higher (1.56 and 1.18) but the median free betahCG was not significantly different (0.923 and 0.933 MoM) than in the normal outcome group. In the preterm delivery group (n = 159), the median free beta-hCG (0.944 MoM) and uterine artery mean PI (1.06) were not significantly different from normal but the median PAPP-A (0.928 MoM) was significantly lower than normal. In screening for pre-eclampsia, the detection rate, for a 5% false-positive rate, was 14.1% for PAPP-A, 54.7% for uterine artery mean PI and 62.1% for a combination of PAPP-A and uterine artery mean PI.

CONCLUSION

Maternal serum PAPP-A at 11-13(+6) of gestation is significantly lower in adverse pregnancy outcomes. The combination of first trimester serum PAPP-A and uterine artery mean PI at 22-24 weeks improves the screening efficacy for the prediction of pre-eclampsia.

Endometriotic Cells Exhibit Metaplastic Change and Oxidative DNA Damage as Well as Decreased Function, Compared to Normal Endometrium

A widely accepted theory of the etiology of endometriosis is that it originates from the implantation and invasion of cells from retrograde menstruation to various sites in the body particularly the pelvic peritoneal cavity. Little is known of the function of these cells in ectopic sites. Normal endometrium was compared with endometriotic tissue using an antibody to Placental Cadherin (P Cadherin), a recently studied cadherin that is implicated in metaplasia and early neoplasia and also 8-hydroxyguanine, an indicator of oxidative DNA damage. Comparisons of endometrial tissue function were made using expression of transforming growth factor beta-1 (TGFbeta-1) and insulin-like growth factor-I (IGF-I). There was no labelling for anti-P Cadherin or anti-8-hydroxydeoxyguanosine in normal endometrium but marked labelling for both on the apical surface of the endometriotic epithelium. Studies of markers of normal endometrial function were all de-expressed in endometriosis. This study indicates that endometriosis cells are abnormal and exhibit oxidative DNA damage, metaplasia and markedly reduced function compared to normal endometrium.

Hormonal monitoring of the first trimester of pregnancy

The hormonal changes and maternal adaptations of human pregnancy are among the most remarkable phenomena in nature. Endocrinologic parameters in the early gestation period have been used to predict abnormal pregnancies and to identify fetuses that have chromosomal aberrations. This article focuses on the changes in hormones that are secreted by the maternal-fetal-placental unit that are unique for the first trimester of pregnancy and their impact on clinical outcome.

IGF-I, 17beta-estradiol and progesterone in SHR and in rats treated with L-NAME: fetal-placental development

METHODS

The relationship between progesterone (P4), 17beta-estradiol, insulin-like growth factor (IGF-I) and embryonic and fetal development, were examined. Female Sprague Dawley rats were divided into two groups: control untreated (n=60) and treated (n=63) with L-NAME (N(omega)-nitro-L-arginine methyl ester), 15 mg/day in drinking water from the first day after mating to day 18 of gestation. A further group was formed (n=63) of spontaneously hypertensive rats (SHR). Mean systolic blood pressure was recorded daily. On days 6, 11 and 18 of pregnancy, the number of sites of implantation, litter and placenta weight was examined. In addition, serum levels of P4, 17beta-estradiol and IGF-I were determined.

RESULTS

Systolic blood pressure (SBP) (mmHg) increased significantly in L-NAME and SHR rats over the course of the experiment. On day 6 of pregnancy, in the L-NAME group the number of implantation sites, levels of IGF-I and 17beta-estradiol were significantly lower than in the control group. In SHR, only the concentration of IGF-I was low (p<0.05). In contrast, on day 11 of pregnancy no variation was found in the parameters under study. On day 18 of gestation, a significant decrease in litter and placenta weight, concentration of P4 and IGF-I was observed in the experimental groups.

CONCLUSION

The data further suggest that nitric oxide might regulate IGF-I production, indicating that growth factors may play an important role in fetal-placental development.

First trimester origins of fetal growth impairment

The timing of factors that lead to disorders of fetal growth have been studied for many years. Previous studies have focused on disorders of the "second wave" of trophoblast invasion of myometrial arterioles and on fetal weight gain in the third trimester. Over the last 5 years, clinical studies have shown associations between first trimester ultrasound and biochemical parameters and the risk of later adverse perinatal outcome. First trimester growth restriction is associated with an increased risk of low birth weight, low birth weight percentile for gestational age and extremely preterm birth. This may reflect a defect in early pregnancy placentation and later adverse outcome. Consistent with this hypothesis, low first trimester circulating maternal concentrations of pregnancy-associated plasma protein A, a trophoblast-derived regulator of the insulin-like growth factor system, are associated with an increased risk of later stillbirth, growth restriction, pre-term birth and pre-eclampsia. Even among healthy women having normal pregnancies, first trimester circulating concentrations of pregnancy-associated plasma protein A correlate with the timing of spontaneous labor and the eventual birth weight. These analyses suggest that in some women complications of late pregnancy have their origins in the very earliest weeks of gestation and precede first attendance for prenatal care.

Association between first trimester maternal serum pregnancy associated plasma protein-A and adverse pregnancy outcome

AIMS

To investigate whether low pregnancy associated plasma protein-A (PAPP-A) levels in the first trimester of pregnancy are associated with subsequent intrauterine fetal growth restriction, stillbirth and preterm delivery.

METHODS

A retrospective review of pregnancy outcomes was undertaken in women who had PAPP-A carried out in the first trimester of pregnancy at the time of nuchal translucency scan. Pregnancy outcomes were assessed by the review of medical records, and postal questionnaires. Delivery details were collected, including livebirth, neonatal birthweight and gestational age at delivery. The chi2 test was used to investigate the association between low first trimester serum PAPP-A levels and adverse fetal outcomes. Unpaired t-test was used for continuous variables. Sensitivities and specificities were then calculated.

RESULTS

A total of 894 women who had blood collected for PAPP-A were identified, and data was obtained for 827 deliveries. Each had a normal karyotype. There were six intrauterine deaths, 13 babies with birthweights below the 3rd centile, 55 babies weighing below the 10th centile, and 96 women who delivered prematurely. Four of six intrauterine deaths had low PAPP-A levels (<0.5 multiples of the median), with a relative risk of 13.75. Low PAPP-A levels were associated with fetal weight below the 10th centile (P = 0.01) but not the 3rd centile. There was no statistically significant association between low maternal serum PAPP-A levels and preterm delivery.

CONCLUSION

At 11-13 weeks' gestation, low maternal serum PAPP-A levels are associated with fetal death in utero and birthweight below the 10th centile. First trimester PAPP-A may be a useful tool for identifying pregnancies at risk of adverse fetal outcomes.

Isocaloric maternal low-protein diet alters IGF-I, IGFBPs, and hepatocyte proliferation in the fetal rat

We investigated the effect of an isocaloric maternal low-protein diet during pregnancy in rats on the proliferative capacity of cultured fetal hepatocytes. The potential roles of these changes on the IGF-IGF-binding protein (IGFBP) axis, and the role of insulin and glucocorticoids in liver growth retardation, were also evaluated. Pregnant Wistar rats were fed a control (C) diet (20% protein) or a low-protein (LP) diet (8%) throughout gestation. In primary culture, the DNA synthesis of hepatocytes derived from LP fetuses was decreased by approximately 30% compared with control hepatocytes (P < 0.05). In parallel, in vivo moderate protein restriction in the dam reduced the fetal liver weight and IGF-I level in fetal plasma (P < 0.01) and augmented the abundance of 29- to 32-kDa IGFBPs in fetal plasma (P < 0.01) and fetal liver (P < 0.01). By contrast, the abundance of IGF-II mRNA in liver of LP fetuses was unaffected by the LP diet. In vitro, the LP-derived hepatocytes produced less IGF-I (P < 0.01) and more 29- to 32-kDa IGFBPs (P < 0.01) than hepatocytes derived from control fetuses. These alterations still appeared after 3-4 days of culture, indicating some persistence in programming. Dexamethasone treatment of control-derived hepatocytes decreased cell proliferation (54 +/- 2.3%, P < 0.01) and stimulated 29- to 32-kDa IGFBPs, whereas insulin promoted fetal hepatocyte growth (127 +/- 5.5%, P < 0.01) and inhibited 29- to 32-kDa IGFBPs. These results show that liver growth and cell proliferation in association with IGF-I and IGFBP levels are affected in utero by fetal undernutrition. It also suggests that glucocorticoids and insulin may modulate these effects.

Protein kinase B alpha/Akt1 regulates placental development and fetal growth

Protein kinase B alpha (PKB alpha/Akt1) is implicated in the regulation of metabolism, transcription, cell survival, angiogenesis, cell migration, growth, and tumorigenesis. Previously, it was reported that PKB alpha-deficient mice are small with increased neonatal mortality (Cho, H., Thorvaldsen, J. L., Chu, Q., Feng, F., and Birnbaum, M. J. (2001) J. Biol. Chem. 276, 38349-38352 and Chen, W. S., Xu, P. Z., Gottlob, K., Chen, M. L., Sokol, K., Shiyanova, T., Roninson, I., Wenig, W., Suzuki, R., Tobe, K., Kadowaki, T., and Hay, N. (2001) Genes Dev. 15, 2203-2208). Here we show that PKB alpha is widely expressed in placenta including all types of trophoblast and vascular endothelial cells. Pkb alpha-/- placentae display significant hypotrophy, with marked reduction of the decidual basalis and nearly complete loss of glycogen-containing cells in the spongiotrophoblast, and exhibit decreased vascularization. Pkb alpha-/- placentae also show significant reduction of phosphorylation of PKB and endothelial nitric-oxide synthase. These defects may cause placental insufficiency, fetal growth impairment, and neonatal mortality. These data represent the first evidence for the role of PKB alpha and endothelial nitricoxide synthase in regulating placental development and provide an animal model for intrauterine growth retardation.

Insulin-like growth factor binding protein 5 and apoptosis in mammary epithelial cells

Insulin-like growth factors (IGFs) are important survival signals that can protect a range of cell types from apoptosis. Although IGF bioavailability is modulated by high affinity interactions with IGF-binding proteins (IGFBPs), there is currently no experimental evidence that IGFBPs regulate the survival function of IGFs in the mammary gland. We have examined IGFBP expression during mammary gland development and studied the effects of IGFBPs on IGF-mediated survival and signalling in mammary epithelial cells in culture. IGFBP-5 protein was greatly increased during days 1-3 of mammary gland involution, when levels of apoptosis are dramatically elevated to remodel the gland after lactation. Primary cultures of mammary epithelial cells (MECs) expressed IGFBP-5 from their basal surface suggesting that IGFBP-5 is suitably located to inhibit IGF signalling. Addition of exogenous IGFBP-5 and IGFBP-3 to MECs suppressed IGF-I-mediated survival, resulting in threefold greater apoptosis in cells incubated with IGF-I and IGFBP-5 compared with IGF-I alone. Examination of signalling pathways involved in apoptosis revealed that phosphorylation of PKB and the forkhead transcription factor, FKHRL1, was induced by IGFs, but that phosphorylation was blocked by IGFBP-5 and IGFBP-3. This study provides evidence that IGFBP-5 plays an important role in the regulation of apoptosis in the mammary gland.

TNF-alpha in pregnancy loss and embryo maldevelopment: a mediator of detrimental stimuli or a protector of the fetoplacental unit?

PURPOSE

Tumor necrosis factor alpha (TNF-alpha), a multifunctional cytokine, has been identified in the ovary, oviduct, uterus, and placenta, and is expressed in embryonic tissues. For many years TNF-alpha was mainly considered to be a cytokine involved in triggering immunological pregnancy loss and as a mediator of various embryopathic stresses. However, data collected during the last decade has characterized TNF-alpha not only as a powerful activator of apoptotic, but also antiapoptotic signaling cascades, as well as revealed its regulatory role in cell proliferation. This review summarizes and conceptualizes the studies addressing TNF-alpha-activated intracellular signaling and the possible functional role of TNF-alpha in embryonic development.

METHODS

Studies addressing the role of TNF-alpha in intercellular signaling, in vivo studies addressing the functional role TNF-alpha in spontaneous and induced pregnancy loss, and studies addressing the role of TNF-alpha in fetal malformations were reviewed. Comparative studies in TNF-alpha knockout and TNF-alpha positive mice were performed to evaluate embryonic death, structural anomalies in fetuses, the degree of apoptosis and cell proliferation, and the activity of molecules such as caspases 3 and 8, the NF-kappaB, (RelA), IkappaBalpha in some target embryonic organs shortly after exposure to embryopathic stresses.

RESULTS

It is proposed that the possible essential function of TNF-alpha may be to prevent the birth of offspring with structural anomalies.

CONCLUSIONS

TNF-alpha will boost death signaling to kill the embryo if initial events (damages) triggered by detrimental stimuli may culminate in structural anomalies, and stimulate protective mechanisms if the repair of these damages may prevent maldevelopment.

Predicting complications of pregnancy with first-trimester maternal serum free-?hCG, PAPP-A and inhibin-A

OBJECTIVE

To find whether fbetahCG, PAPP-A and inhibin-A levels in maternal serum or fetal nuchal translucency (NT) thickness at the first-trimester screening for trisomy 21 (T21) might detect women at high risk for adverse pregnancy outcomes.

METHODS

A retrospective analysis of 1136 women with singleton pregnancy between 10 and 14 weeks. Women with pregnancy complications were allotted to five subgroups: small for gestational age (SGA), large for gestational age (LGA), gestational diabetes (GDM), hypertensive disorders, preterm delivery; women with normal pregnancy represented the control group. NT, maternal serum fbetahCG, PAPP-A and inhibin-A were measured. Mann-Whitney test was used for the comparison of fbetahCG, PAPP-A, inhibin-A and NT between a subgroup of a certain pregnancy complication and the control group. Multivariate logistic regression models were built to explore the relationship among different variables and the occurrence of pregnancy complications.

RESULTS

PAPP-A values were significantly lower in women who delivered SGA babies (n=51, 0.76 MoM; p=0.002) and significantly higher in women who delivered LGA babies (n=120, 1.12 MoM; p=0.036). In women with GDM (n=27), fbetahCG, PAPP-A and inhibin-A were insignificantly lower than in controls, whereas in women with hypertensive disorders (n=56) no significant differences between the groups were found. In women with a preterm delivery (<34 weeks) (n=17), inhibin-A levels were significantly higher (1.25 MoM; p=0.015).

CONCLUSION

Low PAPP-A level is associated with the delivery of an SGA baby and high PAPP-A with the delivery of an LGA baby. High inhibin-A is associated with preterm delivery before 34 weeks. Feto-placental products in the first trimester do not prove to be useful as a screening tool for predicting pregnancy complications.

Bone growth factors in maxillofacial skeletal reconstruction

A literature review was performed to survey the available information on the potential of bone growth factors in skeletal reconstruction in the maxillofacial area. The aim of this review was to characterize the biological and developmental nature of the growth factors considered, their molecular level of activity and their osteogenic potential in craniofacial bone repair and reconstruction. A total of 231 references were selected for evaluation by the content of the abstracts. All growth factors considered have a fundamental role in growth and development. In postnatal skeletal regeneration, PDGF plays an important role in inducing proliferation of undifferentiated mesenchymal cells. It is an important mediator for bone healing and remodelling during trauma and infection. It can enhance bone regeneration in conjunction with other growth factors but is unlikely to provide entirely osteogenic properties itself. IGFs have an important role in general growth and maintenance of the body skeleton. The effect of local application of IGFs alone in craniofacial skeletal defects has not yet shown a clear potential for enhancement of bone regeneration in the reported dosages. The combination of IGF-I with PDGF has been effective in promoting bone regeneration in dentoalveolar defects around implants or after periodontal bone loss. TGFbeta alone in skeletal reconstruction appears to be associated with uncertain results. The presence of committed cells is required for enhancement of bone formation by TGFbeta. It has a biphasic effect, which suppresses proliferation and osteoblastic differentiation at high concentrations. BMPs, BMP2, BMP4 and BMP7 in particular, appear to be the most effective growth factors in terms of osteogenesis and osseous defect repair. Efficacy of BMPs for defect repair is strongly dependent on the type of carrier and has been subject to unknown factors in clinical feasibility trials resulting in ambiguous results. The current lack of clinical data may prolong the period until this factor is introduced into routine clinical application. PRP is supposed to increase proliferation of undifferentiated mesenchymal cells and to enhance angiogenesis. There is little scientific evidence about the benefit of PRP in skeletal reconstructive and preprosthetic surgery yet and it is unlikely that peri-implant bone healing or regeneration of local bone into alloplastic material by the application of PRP alone will be significantly enhanced.

Early pregnancy levels of pregnancy-associated plasma protein a and the risk of intrauterine growth restriction, premature birth, preeclampsia, and stillbirth

The risk of adverse perinatal outcome among 8839 women recruited to a multicenter, prospective cohort study was related to maternal circulating concentrations of trophoblast-derived proteins at 8-14 wk gestation. Women with a pregnancy-associated plasma protein A (PAPP-A) in the lowest fifth percentile at 8-14 wk gestation had an increased risk of intrauterine growth restriction [adjusted odds ratio, 2.9; 95% confidence interval (CI), 2.0-4.1], extremely premature delivery (adjusted odds ratio, 2.9; 95% CI, 1.6-5.5), moderately premature delivery (adjusted odds ratio, 2.4; 95% CI, 1.7-3.5), preeclampsia (adjusted odds ratio, 2.3; 95% CI, 1.6-3.3), and stillbirth (adjusted odds ratio, 3.6; 95% CI, 1.2-11.0). The strengths of the associations were similar when the test was performed before 13 wk gestation or between 13 and 14 wk gestation. In contrast, levels of free beta-human CG, another circulating protein synthesized by the syncytiotrophoblast, were not predictive of later outcome in multivariate analysis. PAPP-A has been identified as a protease specific for IGF binding proteins. We conclude that control of the IGF system in the first and early second trimester trophoblast may have a key role in determining subsequent pregnancy outcome.

Nutrient insult in early pregnancy

Nutrient insults in early pregnancy, such as nutrient deprivation during famines, are often associated with an unfavourable outcome. Suboptimal nutrition in the early stage of gestation has been linked to a number of adverse effects on fetal growth and development. Historically, nausea and vomiting in pregnancy (NVP) was an important contributor to pregnancy-related mortality; indeed, Charlotte Bronte died from starvation and dehydration after suffering very severe NVP 4 months into her first pregnancy (Gaskell, 1858). Although NVP seldom now progresses to be life-threatening, it affects the majority of pregnant women, and potentially presents a challenge to nutrient intake in the most vulnerable period of development. Symptoms range from mild (nausea only) to severe (a level of vomiting that restricts nutrient intake and ultimately threatens metabolic and electrolyte balance). Although NVP has been documented for thousands of years, its cause has not yet been satisfactorily elucidated, but seems to be related to endocrinological changes. Pregnant women also frequently report dietary cravings and aversions during pregnancy which can be linked to both the incidence and severity of NVP. Paradoxically, NVP appears to be positively associated with a favourable outcome of pregnancy, including increased birth weight and gestational age. The mechanisms by which NVP favours the outcome of pregnancy are not known. They may be related to women increasing their nutrient intake to alleviate symptoms, improving the quality of their diet or reducing energy expenditure. Alternatively, adaptation to a reduced nutrient intake might stimulate the expression of growth factors and affect placentation or metabolism, thus favouring fetal growth when NVP resolves.

Effects of early undernutrition on the brain insulin-like growth factor-I system

Undernutrition reduces circulating concentrations of insulin-like growth factor (IGF)-I, but how it affects the brain IGF system, especially during development, is largely unknown. We have studied IGF-I, IGF-II, IGF receptor and IGF binding protein (BP)-2 mRNA expression in the hypothalamus, cerebellum and cerebral cortex of neonatal rats that were food restricted beginning on gestational day 16. One group was refed starting on postnatal day 14. Rats were killed on postnatal day 8 or 22. Undernutrition did not produce an overall reduction in brain weight at either age but, at 22 days, both the cerebellum and hypothalamus weighed significantly less. At 8 days, no change was detected in the central IGF axis in response to undernutrition. However, in 22-day-old undernourished rats, IGF-I and IGF receptor mRNA expression were increased in both the hypothalamus and cerebellum, while IGFBP-2 was decreased, but only in the hypothalamus. Refeeding had no effect on any of these parameters. These results suggest that the hypothalamus and cerebellum respond to malnutrition and the decrease in circulating IGF-I, a peptide fundamental for growth and development, by increasing the local production of both the growth factor and its receptor in attempt to maintain normal development.

Obstruction of ductus venosus stimulates cell proliferation in organs of fetal sheep

In growth restricted fetuses, hepatic blood flow is reduced. This suggests the hypothesis that liver blood flow controls fetal growth. In 11 near term sheep the ductus venosus was blocked with an embolization coil in one fetus (experimental) and left patent in the twin (control). Arterial catheters were placed in both fetuses. After termination [mean (s.d.) 5 days (2) after surgery] the fetal body and organs were weighed. The cell proliferation rate (pKi-67) was determined in tissue samples of the liver, heart, skeletal muscle, kidneys and placenta (n=6). Blood flow through the umbilical vein measured by Doppler ultrasound did not differ in control and experimental fetuses [experimental: 600 (101) ml/min; control: 626 (89) ml/min]. In experimental fetuses, blood flow through the ductus venosus was negligible (colour Doppler), and thus hepatic blood flow was increased. Absolute and relative (percentage of body weight) liver weights were increased in experimental fetuses [liver weight: 119 (34) g versus 84 (17) g; relative liver weight: 4.3 (0.8) per cent versus 3.4 (0.8) per cent;P=0.002, n=11]. The cell proliferation rate was increased significantly (twofold) in heart muscle, skeletal muscle and kidneys, and sixfold in liver. It is concluded that increases of hepatic blood flow stimulate cell proliferation in major organs of the ovine fetus.

IGF-II promotes mesoderm formation

IGF-II is abundant in the nascent mesoderm of the gastrulating mouse embryo. Its function at this developmental stage is unknown. We investigated it by following the in vitro and in vivo differentiation of several androgenetic, biparental, parthenogenetic, and androgenetic Igf2 -/- murine ES cell lines; these cells differed in endogenous IGF-II levels because Igf2 is paternally expressed in the mouse embryo in most tissues. The expression of mesoderm markers and the subsequent formation of muscle structures were correlated with endogenous IGF-II level during teratoma formation and during in vitro differentiation. In addition, the absence of Igf2 in androgenetic Igf2 -/- ES cells led to a severe impairment of mesoderm development, demonstrating the dependence of the preferential mesoderm development of androgenetic ES cells upon Igf2 activity, among the numerous known imprinted genes. The addition of exogenous IGF-II to in vitro differentiation culture medium led to a specific increase in the expression of mesoderm markers. Thus, we propose a novel model in which the binding of IGF-II to its principal signaling receptor, IGF1R, at the surface of mesoderm precursor cells increases the formation of mesoderm cells.

Regulation and localization of insulin-like growth factor binding protein-5 gene expression in the uterus and placenta of the cyclic and early pregnant ewe

The insulin-like growth factor (IGF) system plays an important role in the regulation of uterine function and placental growth. However, there is little information regarding the localization and regulation of IGF binding protein-5 (IGFBP-5) in the reproductive tract. The distribution of this IGFBP was therefore investigated using in situ hybridization in sections of utero-placental tissue obtained throughout the estrous cycle, up to Day 55 of gestation, and on Days 16-17 from both horns of ewes with unilateral pregnancies that followed uterine transection. In nonpregnant ewes, IGFBP-5 mRNA was present at high concentrations in the maternal caruncles and luminal epithelium, and at moderate levels in myometrium. In these regions IGFBP-5 mRNA showed cyclic variations, with concentrations peaking around ovulation, whereas low expression in the endometrial stroma remained constant. During pregnancy, there was additional localization to the endometrial glands; and in all regions, with the exception of the caruncles, concentrations increased significantly with gestational age. In transected uteri, concentrations in the luminal epithelium of the pregnant horn were significantly higher than those in the nonpregnant horn. In the caruncles, IGFBP-5 mRNA formed an intense band just below the tips of the invading fetal villi. Below this band, IGFBP-5 mRNA localized to form a series of rings, which could create a route to allow the fetal villi access into the caruncular stroma for nutrient exchange. In conclusion, IGFBP-5 is abundantly expressed in the ovine reproductive tract, with both the concentration and localization differentially regulated during the cycle and pregnancy.

Human insulin-like growth factor (IGF) binding protein-1 inhibits IGF-I-stimulated body growth but stimulates growth of the kidney in snell dwarf mice

The actions of insulin-like growth factor-I (IGF-I) are modulated by IGF binding proteins (IGFBPs). The effects of IGFBP-1 in vivo are insufficiently known, with respect to inhibitory or stimulatory actions on IGF-induced growth of specific organs. Therefore, we studied the effects of IGFBP-1 on IGF-I-induced somatic and organ growth in pituitary-deficient Snell dwarf mice. Human GH, IGF-I, IGFBP-1, and a preequilibrated combination of equimolar amounts of IGF-I and IGFBP-1 were administered sc during 4 weeks. Treatment with IGF-I alone induced a significant increase in body length (108% of control) and weight (112%) as well as an increase in weight of the submandibular salivary glands (135%), kidneys (124%), femoral muscles (111%), testes (129%), and spleen (126%) compared with saline-treated controls. IGFBP-1 alone induced a significant increase in weight of the kidneys (152% of control). Coadministration of IGF-I with IGFBP-1 neutralized the stimulating effects of IGF-I on body length and weight as well as on the femoral muscles and testes. In contrast, the weights of the submandibular salivary glands (143%) were not significantly different from those of IGF-I-treated animals, whereas the weights of the kidneys (171%) and spleen (156%) were significantly increased compared with IGF-I-treated mice. The effect of IGFBP-1 plus IGF-I on kidney weight was not significantly greater than the effect of IGFBP-1 alone. Western ligand blotting showed induction of the IGFBP-3 doublet as well as IGFBPs with molecular masses of 24 kDa, most probably IGFBP-4, by human GH, IGF-I alone, and IGF-I in combination with IGFBP-1. Our data show that coadministration of IGFBP-1 inhibits IGF-I-induced body growth of GH-deficient mice but significantly stimulates the growth promoting effects of IGF-I on the kidneys and the spleen. These data warrant further investigation because differences in concentrations of IGFBP-1 occurring in vivo may influence IGF-I-induced anabolic processes.

The insulin-like growth factors (IGFs) and IGF binding proteins in postnatal development of murine mammary glands

The insulin-like growth factors are mitogens and survival factors for normal mammary epithelial cells in vitro. Data reviewed here demonstrate that mRNAs for IGF-I and IGF-II, the IGF type I receptor and the IGFBPs are expressed locally in mammary tissue during pubertal and pregnancy-induced growth and differentiation of murine mammary glands. IGF-I, IGF-II and the IGF-IR were expressed in terminal end buds (TEBs) in virgin glands during ductal growth. In addition, IGF-II and IGF-IR mRNAs were expressed in ductal and alveolar epithelium in glands throughout postnatal development. Consistent with these results, IGF-I promoted ductal growth and proliferation in mouse mammary glands in organ culture. In addition to endogenous expression of the IGFs and IGF-IR, the IGFBPs showed a varied pattern of expression in mammary tissue during postnatal development. For example, IGFBP-3 and -5 mRNAs were expressed in TEBs and ducts while IGFBP-2 and -4 mRNAs were expressed in stromal cells immediately surrounding the epithelium. These results support a role for the IGFs and IGFBPs as local mediators of postnatal mammary gland growth and differentiation.

Differential expression of insulin-like growth factors in the uterine epithelium and extracellular matrix during early pregnancy

We have studied the simultaneous expression of insulin-like growth factor I (IGF-I) and insulin-like growth factor II (IGF-II) in the uterine epithelium and extracellular matrix during the time of trophoblast attachment and implantation. These studies reveal that IGF-I and IGF-II display different spatial and temporal patterns of expression during early pregnancy, and suggest a role for them in the process of attachment and implantation. Specifically, IGF-I is strongly expressed in the basal lamina which is the site of trophoblast invasion into the maternal stroma, and also in the apical epithelium, the site of initial trophoblast attachment. IGF-II is expressed to a lesser extent in the basal lamina, lateral plasma membranes and apical epithelium on day 3 but is only prominent apically at the time of implantation, suggesting a role in attachment.

IGF binding protein-1 (IGFBP-1) is preferentially associated with the fetal-facing basal surface of the syncytiotrophoblast in the human placenta

IGF receptors are expressed in a spatially polarized manner on the syncytiotrophoblast cell membrane. We therefore examined the hypothesis that IGFBPs expressed at the maternal-fetal interface interact with distinct surfaces of the syncytiotrophoblast membrane to modulate IGF function. Membrane vesicles were prepared specifically from the maternal-facing, microvillous membrane (MVM) and the fetal-facing, basal membrane (BM) surfaces of the syncytiotrophoblast. The association of IGFBPs with each membrane preparation was determined by ligand blot analysis. A doublet migrating at 38/42 kD was detected in both MVM and BM preparations. Selective immunoprecipitation followed by ligand blot analysis identified this IGF binding species as IGFBP-3. Additionally, a protein migrating at approximately 29 kD was associated primarily with the BM. This protein was identified as IGFBP-1 by both immunoprecipitation and ligandblotting techniques. Non-denaturing PAGE revealed five distinct bands corresponding to different degrees of phosphorylation. The phosphorylation pattern of BM-associated IGFBP-1 was identical to that of native IGFBP-1 in amniotic fluid. Immunohistological analysis of term placenta revealed IGFBP-1-specific staining of the syncytiotrophoblast and the fetal capillary/pericapillary bed. The localization of IGFBP-1 to a distinct compartment within the fetal placenta, not in proximity to the syncytiotrophoblast type I IGF receptor, suggests it may play a role in regulating/targeting IGF activity within the stromal compartment or by exerting IGF-independent effects on the basal surface of the syncytiotrophoblast. The nature of its binding to the BM has not been determined.