Insulin-Like Growth Factor Axis and Gestational Diabetes Mellitus: A Longitudinal Study in a Multiracial Cohort

The potential of circulating free DNA of methylated IGFBP as a biomarker for type 2 diabetes Mellitus: A Comprehensive review

T2DM detection methods are commonly used in teens and adults but are generally unsuitable to unborn fetuses in the context of non-invasive prenatal testing (NIPT). Biophysical and biochemical tests for fetuses are often invasive, carry risks, and have low sensitivity and specificity, with no direct method available to diagnose T2DM in utero. In contrast, cell-free DNA (cfDNA) is known have high sensitivity (93-98 %) and specificity (94-100 %) for cancer detection and fetal genetic disorders (trisomy 21, 8, and 13) making it applicable for fetal epigenetic and genetic analysis, including T2DM early detection. However, no study has explored its use for this purpose. Our review focuses on the potential of IGFBP methylation levels in cfDNA as biomarkers for NIPT of T2DM. Placental global hypomethylation in GDM may predict T2DM during the prenatal period, and a similar pattern potentially be detected in cfDNA. Targeted genes reliable for NIPT, such as IGFBPs are needed because their significant role in T2DM and GDM. Among these, IGFBP-1 and IGFBP-2 have shown potential as predictive genes, exhibiting hypermethylation in placental tissue from GDM cases. This hypermethylation reduces their expression and the formation of the IGF-1-IGFBP complex, leading to increased levels of free IGF-1, which is associated with T2DM in the fetus. Hypermethylation regions have longer fragment sizes in cfDNA, thus in T2DM cases, hypermethylation of IGFBP-1 and IGFBP-2 from fetus results in longer cfDNA fragments. Therefore, analyzing the methylation levels and fragment sizes of IGFBP-1 or IGFBP-2 cfDNA could be a promising biomarker for identifying fetal T2DM risk non-invasively.

Nonlinear association between alanine aminotransferase to high-density lipoprotein cholesterol ratio and risk of gestational diabetes mellitus

Previous studies have indicated a potential association between the alanine aminotransferase to high-density lipoprotein cholesterol (ALT/HDL-C) ratio and the risk of Type 2 Diabetes Mellitus, but its relation with gestational diabetes mellitus (GDM) remains uncertain. This study aims to investigate the correlation between the ALT/HDL-C ratio in early pregnancy and the risk of GDM. This study is a secondary analysis based on an open-source cohort study. A total of 590 single pregnant women attending two hospitals in Korea up to 14 weeks gestation were included between November 2014 and July 2016. Logistic regression analysis, subgroup analysis, and smooth curve fitting were employed to explore the association between the ALT/HDL-C ratio and GDM risk. The predictive capability of the ALT/HDL-C ratio for GDM was assessed using ROC curve analysis. The average age of participants was 32.06 ± 3.80 years, with a GDM incidence rate of 6.27%. Multifactorial logistic regression analysis revealed that the serum ALT/HDL-C ratio is an independent influencing factor for GDM (OR = 1.08, 95% CI: 1.02-1.16). Furthermore, a non-linear relationship between the ALT/HDL-C ratio and GDM risk was observed, with a turning point at 5.51. The effect size (OR) on the left and right sides of the turning point were 0.75 (95% CI: 0.37-1.59) and 1.55 (95% CI: 1.18-2.00), respectively. Additionally, when combined with age, pre-pregnancy body mass index, parity, and insulin resistance index in a prediction model for GDM, the ALT/HDL-C ratio demonstrated improved sensitivity of prediction by reaching up to 67.6%, specificity of prediction by reaching up to 87.3%, and an area under curve value of 0.819 (95%CI: 0.743-0.894). In early pregnancy, the serum ALT/HDL-C ratio shows a positive correlation with maternal risk in a nonlinear manner. The combination of ALT/HDL-C ratio with maternal characteristics and metabolic indicators provides good predictive value for GDM. This study may facilitate optimization of GDM prevention in pregnant women and enable timely and effective intervention to enhance their prognosis.

Prediction of gestational diabetes mellitus by multiple biomarkers at early gestation

BACKGROUND

It remains unclear which early gestational biomarkers can be used in predicting later development of gestational diabetes mellitus (GDM). We sought to identify the optimal combination of early gestational biomarkers in predicting GDM in machine learning (ML) models.

METHODS

This was a nested case-control study including 100 pairs of GDM and euglycemic (control) pregnancies in the Early Life Plan cohort in Shanghai, China. High sensitivity C reactive protein, sex hormone binding globulin, insulin-like growth factor I, IGF binding protein 2 (IGFBP-2), total and high molecular weight adiponectin and glycosylated fibronectin concentrations were measured in serum samples at 11-14 weeks of gestation. Routine first-trimester blood test biomarkers included fasting plasma glucose (FPG), serum lipids and thyroid hormones. Five ML models [stepwise logistic regression, least absolute shrinkage and selection operator (LASSO), random forest, support vector machine and k-nearest neighbor] were employed to predict GDM. The study subjects were randomly split into two sets for model development (training set, n = 70 GDM/control pairs) and validation (testing set: n = 30 GDM/control pairs). Model performance was evaluated by the area under the curve (AUC) in receiver operating characteristics.

RESULTS

FPG and IGFBP-2 were consistently selected as predictors of GDM in all ML models. The random forest model including FPG and IGFBP-2 performed the best (AUC 0.80, accuracy 0.72, sensitivity 0.87, specificity 0.57). Adding more predictors did not improve the discriminant power.

CONCLUSION

The combination of FPG and IGFBP-2 at early gestation (11-14 weeks) could predict later development of GDM with moderate discriminant power. Further validation studies are warranted to assess the utility of this simple combination model in other independent cohorts.

Mediating Effect of Insulin-Like Growth Factor-I Underlying the Link Between Vitamin D and Gestational Diabetes Mellitus

Vitamin D was well-known to be associated with gestational diabetes mellitus (GDM). Insulin-like growth factor-I (IGF-I) has been linked to vitamin D and GDM, respectively. We hypothesize that changes in IGF-I metabolism induced by 25(OH)D3 might contribute to GDM. Therefore, we investigated the independent and combined relationships of serum 25(OH)D3 and IGF-I concentrations with GDM risk, and the mediation effect of IGF-I on 25(OH)D3. A total of 278 pregnant women (including 125 cases and 153 controls) were recruited in our current study. Maternal serum 25(OH)D3 and IGF-I were measured in the second trimester. Logistic regression models were used to estimate the associations of 25(OH)D3 and IGF-I concentrations with the risk of GDM. Mediation analyses were used to explore the mediation effect of IGF-I on the association between 25(OH)D3 and the risk of GDM. After adjusted for the confounded factors, both the third and fourth quartile of 25(OH)D3 decreased the risk of GDM (OR = 0.226; 95% CI, 0.103-0.494; OR = 0.109; 95% CI, 0.045-0.265, respectively) compared to the first quartile of 25(OH)D3. However, the third and fourth quartile of serum IGF-I (OR = 5.174; 95% CI, 2.287-11.705; OR = 12.784; 95% CI, 5.292-30.879, respectively) increased the risk of GDM compared to the first quartile of serum IGF-I. Mediation analyses suggested that 19.62% of the associations between 25(OH)D3 and GDM might be mediated by IGF-I. The lower concentration of serum 25(OH)D3 or higher IGF-I in the second trimester was associated with an increased risk of GDM. The serum IGF-I level might be a potential mediator between 25(OH)D3 and GDM.

Epigenetic modifications of placenta in women with gestational diabetes mellitus and their offspring

Gestational diabetes mellitus (GDM) is a pregnancy-related complication characterized by abnormal glucose metabolism in pregnant women and has an important impact on fetal development. As a bridge between the mother and the fetus, the placenta has nutrient transport functions, endocrine functions, etc., and can regulate placental nutrient transport and fetal growth and development according to maternal metabolic status. Only by means of placental transmission can changes in maternal hyperglycemia affect the fetus. There are many reports on the placental pathophysiological changes associated with GDM, the impacts of GDM on the growth and development of offspring, and the prevalence of GDM in offspring after birth. Placental epigenetic changes in GDM are involved in the programming of fetal development and are involved in the pathogenesis of later chronic diseases. This paper summarizes the effects of changes in placental nutrient transport function and hormone secretion levels due to maternal hyperglycemia and hyperinsulinemia on the development of offspring as well as the participation of changes in placental epigenetic modifications due to maternal hyperglycemia in intrauterine fetal programming to promote a comprehensive understanding of the impacts of placental epigenetic modifications on the development of offspring from patients with GDM.

IGF1R stimulates autophagy, enhances viability, and promotes insulin secretion in pancreatic β cells in gestational diabetes mellitus by upregulating ATG7

Gestational diabetes mellitus (GDM) is a prevalent metabolic disturbance in pregnancy. This article investigated the correlations between serum IGF1R and ATG7 with insulin resistance (IR) in GDM patients. Firstly, 100 GDM patients and 100 healthy pregnant women were selected as study subjects. The levels of serum IGF1, IGF1R, and ATG7 and their correlations with the insulin resistance index homeostasis model assessment of insulin resistance (HOMA-IR) were measured and analyzed by ELISA and Pearson. Additionally, in mouse pancreatic β cells, IGF1R, ATG7, Beclin-1, and LC3-II/LC3-I levels, cell viability/apoptosis, and insulin level were assessed by western blot, CCK-8, flow cytometry, and ELISA. The GDM group exhibited obviously raised serum IGF1 level and diminished serum IGF1R/ATG7 levels. The IGF1 level was positively correlated with HOMA-IR, while IGF1R/ATG7 levels were negatively correlated with HOMA-IR in GDM patients. Collectively, IGF1R stimulated cell viability, suppressed apoptosis, amplified insulin secretion, and increased ATG7 expression to induce cell autophagy, which could be partially averted by ATG7 silencing.

Associations Between Prenatal Blood Metals and Vitamins and Cord Blood Peptide Hormone Concentrations

Background

Nonessential metals have endocrine disrupting properties, interfere with cellular processes, generate reactive oxygen and deplete antioxidants, while essential metals and vitamins act as antioxidants. The extent to which prenatal metals and vitamins are associated with cord blood hormones involved in maternal and fetal metabolic and growth processes is unknown.

Methods

We measured six nonessential (arsenic, barium, cadmium, cesium, lead, mercury) and four essential (magnesium, manganese, selenium, zinc) metals and trace elements, and two vitamins (B12 and folate) in first trimester blood from participants in the longitudinal pre-birth Project Viva cohort, who were recruited between 1999-2002 in eastern Massachusetts. We measured adiponectin, C-peptide, IGF-1, IGF-2, IGFBP-3, insulin, and leptin concentrations in cord blood (~n=695). We used covariate-adjusted quantile g-computation for mixtures and linear regression for individual exposures to estimate associations with cord blood peptide hormones.

Results

The essential metal mixture (magnesium, manganese, selenium, zinc) was associated with higher IGF-1 (β=3.20 ng/ml per quartile, 95% CI: 0.39, 6.01), IGF-2 (β=10.93 ng/ml, 95% CI: 0.08, 21.79), and leptin (β=1.03 ng/ml, 95% CI: 0.25, 1.80). Magnesium was associated with higher leptin (β=2.90 ng/ml, 95% CI: 0.89, 4.91), while B12 was associated with lower adiponectin, IGF-2, and leptin, but higher C-peptide. Other individual nonessential metals were associated with cord blood hormones.

Conclusions

Our findings suggest that some prenatal metals and vitamins are associated with cord blood hormones, which may influence growth and development.

Longitudinal lipidomic profiles during pregnancy and associations with neonatal anthropometry: findings from a multiracial cohort

BACKGROUND

Maternal lipidomic profiling offers promise for characterizing lipid metabolites during pregnancy, but longitudinal data are limited. This study aimed to examine associations of longitudinal lipidomic profiles during pregnancy with multiple neonatal anthropometry using data from a multiracial cohort.

METHODS

We measured untargeted plasma lipidome profiles among 321 pregnant women from the NICHD Fetal Growth Study-Singletons using plasma samples collected longitudinally during four study visits at gestational weeks (GW) 10-14, 15-26, 23-31, and 33-39, respectively. We evaluated individual lipidomic metabolites at each study visit in association with neonatal anthropometry. We also evaluated the associations longitudinally by constructing lipid networks using weighted correlation network analysis and common networks using consensus network analysis across four visits using linear mixed-effects models with the adjustment of false discover rate.

FINDINGS

Multiple triglycerides (TG) were positively associated with birth weight (BW), BW Z-score, length and head circumference, while some cholesteryl ester (CE), phosphatidylcholine (PC), sphingomyelines (SM), phosphatidylethanolamines (PE), and lysophosphatidylcholines (LPC 20:3) families were inversely associated with BW, length, abdominal and head circumference at different GWs. Longitudinal trajectories of TG, PC, and glucosylcermides (GlcCer) were associated with BW, and CE (18:2) with BW z-score, length, and sum of skinfolds (SS), while some PC and PE were significantly associated with abdominal and head circumference. Modules of TG at GW 10-14 and 15-26 mainly were associated with BW. At GW 33-39, two networks of LPC (20:3) and of PC, TG, and CE, showed inverse associations with abdominal circumference. Distinct trajectories within two consensus modules with changes in TG, CE, PC, and LPC showed significant differences in BW and length.

INTERPRETATION

The results demonstrated that longitudinal changes of TGs during early- and mid-pregnancy and changes of PC, LPC, and CE during late-pregnancy were significantly associated with neonatal anthropometry.

FUNDING

National Institute of Child Health and Human Development intramural funding.

Expression of insulin-like growth factor binding protein-3 in HELLP syndrome

OBJECTIVE

To investigate the expression of insulin-like growth factor binding protein-3(IGFBP-3) in HELLP syndrome and its possible role in the pathogenesis of this disease.

METHODS

1) 87 subjects were enrolled, including 29 patients with HELLP syndrome, 29 patients with pre-eclampsia (PE), and 29 healthy gravidae as control. The levels of IGFBP-3, IGF-1, TGF-β1, and VEGF in maternal and umbilical blood of them were detected using ELISA. Correlation analysis was used to observe the correlation between IGFBP-3 and IGF-1/TGF-β1/VEGF in maternal and umbilical blood, as well as that between maternal serum IGFBP-3 and clinical diagnostic indicators of HELLP syndrome. 2) Human hepatic sinusoid endothelial cells (HLSEC) and human umbilical vein endothelial cells (HUVEC) were cultured with different concentrations of IGFBP-3. After 72 h of culture, cell apoptosis and the normal living cells rate were detected and compared.

RESULTS

1) In both maternal and umbilical blood of HELLP group, levels of IGFBP-3 and TGF-β1 were higher than control and PE group, IGF-1was lower than control group, VEGF was lower than control and PE group. IGFBP-3 in maternal blood was correlated with IGF-1/TGF-β1/ VEGF, while IGFBP-3 in umbilical blood was linked to IGF-1/TGF-β1. In maternal blood, there was a negative correlation between PLT and IGFBP-3, and a positive correlation between ALT/AST/LDH and IGFBP-3. 2) After cultured with IGFBP-3, the total apoptosis rate of either HLSEC or HUVEC was considerably elevated, while the normal living rate was decreased.

CONCLUSION

The expression of IGFBP-3 is elevated in HELLP syndrome, which may subsequently promote cell apoptosis by affecting the expression and function of IGF-1, VEGF, and TGFβ1 in the IGF/PI3K/Akt, TGF-β1/Smad3, and VEGF/eNOS/NO pathways. IGFBP-3 aggravates inflammatory reactions of the vascular endothelium and liver under hypoxia, affects the normal function of cells, and plays a role in the pathogenesis of diseases.

Adiponectin, IGFBP-1 and -2 are independent predictors in forecasting prediabetes and type 2 diabetes

Objective

Adiponectin and insulin-like growth factor (IGF) binding proteins IGFBP-1 and IGFBP-2 are biomarkers of insulin sensitivity. IGFBP-1 reflects insulin sensitivity in the liver, adiponectin in adipose tissue and IGFBP-2 in both tissues. Here, we study the power of the biomarkers adiponectin, IGFBP-1, IGFBP-2, and also included IGF-I and IGF-II, in predicting prediabetes and type 2 diabetes (T2D) in men and women with normal oral glucose tolerance (NGT).

Design

Subjects with NGT (35-56 years) recruited during 1992-1998 were re-investigated 8-10 years later. In a nested case control study, subjects progressing to prediabetes (133 women, 164 men) or to T2D (55 women, 98 men) were compared with age and sex matched NGT controls (200 women and 277 men).

Methods

The evaluation included questionnaires, health status, anthropometry, biochemistry and oral glucose tolerance test.

Results

After adjustment, the lowest quartile of adiponectin, IGFBP-1 and IGFBP-2 associated independently with future abnormal glucose tolerance (AGT) in both genders in multivariate analyses. High IGFs predicted weakly AGT in women. In women, low IGFBP-2 was the strongest predictor for prediabetes (OR:7.5), and low adiponectin for T2D (OR:29.4). In men, low IGFBP-1 was the strongest predictor for both prediabetes (OR:13.4) and T2D (OR:14.9). When adiponectin, IGFBP-1 and IGFBP-2 were combined, the ROC-AUC reached 0.87 for women and 0.79 for men, higher than for BMI alone.

Conclusion

Differences were observed comparing adipocyte- and hepatocyte-derived biomarkers in forecasting AGT in NGT subjects. In women the strongest predictor for T2D was adiponectin and in men IGFBP-1, and for prediabetes IGFBP-2 in women and IGFBP-1 in men.

Association between gestational diabetes mellitus and bioavailability of insulin-like growth factors and role of their binding proteins

OBJECTIVE

Insulin-like growth factors (IGFs) are involved in regulating growth and metabolism and increase insulin sensitivity, improve glucose metabolism, and are potentially related to gestational diabetes mellitus (GDM) and its complications for mothers and fetuses.

DESIGN

This study aimed to assess serum levels and cord blood levels of IGF system components in pregnant women with (39 participants) and without GDM (22 participants). Blood samples were obtained at 28-32 and 36-38 weeks of gestation and 6-12 months after delivery. Cord blood samples were obtained during delivery. Results between both groups as well as between single visits were statistically compared.

RESULTS

Both IGF1 and IGF2 maternal serum levels did not differ between the GDM and non-GDM groups. However, levels of IGF-binding proteins (IGFBPs) were different. IGFBP4 levels were decreased during pregnancy and after delivery in women with GDM, while IGFBP7 levels were increased during pregnancy in women with GDM. Cord blood IGFBP3 and IGFBP7 levels were increased (p < 0.001 for IGFBP3, p = 0.003 for IGFBP7), while IGFBP4 levels were decreased (p < 0.001) in the GDM group compared with the non-GDM group.

CONCLUSIONS

Although IGF levels did not differ, changes in their function level could still persist possibly because of the effects of the binding proteins, especially their promoting or inhibitory effects on IGFs. These results should be considered in interpretation of IGF levels.

Polygenic Risk Score and Risk Factors for Gestational Diabetes

Gestational diabetes mellitus (GDM) is a common complication of pregnancy that adversely affects maternal and offspring health. A variety of risk factors, such as BMI and age, have been associated with increased risks of gestational diabetes. However, in many cases, gestational diabetes occurs in healthy nulliparous women with no obvious risk factors. Emerging data suggest that the tendency to develop gestational diabetes has genetic and environmental components. Here we develop a polygenic risk score for GDM and investigate relationships between its genetic architecture and genetically constructed risk factors and biomarkers. Our results demonstrate that the polygenic risk score can be used as an early screening tool that identifies women at higher risk of GDM before its onset allowing comprehensive monitoring and preventative programs to mitigate the risks.

Gestational Diabetes Mellitus and Energy-Dense Diet: What Is the Role of the Insulin/IGF Axis?

Gestational diabetes mellitus (GDM), is one of the most important pregnancy complications affecting approximately 15% of pregnant women. It is related to several gestational adverse outcomes in the fetus, e.g., macrosomia, shoulder dystocia, stillbirth, neonatal hypoglycemia, and respiratory distress. Women with GDM have a high risk of developing type 2 diabetes in the future. The pathogenesis of GDM is not completely understood; nevertheless, two factors could contribute to its development: β-cell dysfunction and failure in insulin secretion in response to insulin resistance induced by gestation. Both processes, together with the physiological activities of the insulin-like growth factors (IGFs), play a crucial role in glucose transport to the fetus and hence, fetal growth and development. IGFs (both IGF-1 and IGF-2) and their binding proteins (IGFBPs) regulate glucose metabolism and insulin sensitivity. Maternal nutritional status determines the health of the newborn, as it has substantial effects on fetal growth and development. Maternal obesity and an energy-dense diet can cause an increase in insulin and IGF-1 serum levels, producing metabolic disorders, such as insulin resistance, GDM, and high birth weight (> 4,000 g) due to a higher level of body fat. In this way, in GDM pregnancies there is an increase in IGF-1 and IGF-2 serum levels, and a decrease in IGFBP-1 and 4 serum levels, suggesting the crucial role of the insulin/IGF system in this gestational outcome. Here, the present review tries to elucidate the role that energy-dense diets and the insulin/IGF-1 signaling pathway perform in GDM pregnancies.

Plasma Acylcarnitines during Pregnancy and Neonatal Anthropometry: A Longitudinal Study in a Multiracial Cohort

As surrogate readouts reflecting mitochondrial dysfunction, elevated levels of plasma acylcarnitines have been associated with cardiometabolic disorders, such as obesity, gestational diabetes, and type 2 diabetes. This study aimed to examine prospective associations of acylcarnitine profiles across gestation with neonatal anthropometry, including birthweight, birthweight z score, body length, sum of skinfolds, and sum of body circumferences. We quantified 28 acylcarnitines using electrospray ionization tandem mass spectrometry in plasma collected at gestational weeks 10–14, 15–26, 23–31, and 33–39 among 321 pregnant women from the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singletons. A latent-class trajectory approach was applied to identify trajectories of acylcarnitines across gestation. We examined the associations of individual acylcarnitines and distinct trajectory groups with neonatal anthropometry using weighted generalized linear models adjusting for maternal age, race/ethnicity, education, parity, gestational age at blood collection, and pre-pregnancy body mass index (BMI). We identified three distinct trajectory groups in C2, C3, and C4 and two trajectory groups in C5, C10, C5–DC, C8:1, C10:1, and C12, respectively. Women with nonlinear decreasing C12 levels across gestation (5.7%) had offspring with significantly lower birthweight (−475 g; 95% CI, −942, −6.79), birthweight z score (−0.39, −0.71, −0.06), and birth length (−1.38 cm, −2.49, −0.27) than those with persistently stable C12 levels (94.3%) (all nominal p value < 0.05). Women with consistently higher levels of C10 (6.1%) had offspring with thicker sum of skinfolds (4.91 mm, 0.85, 8.98) than did women with lower levels (93.9%) during pregnancy, whereas women with lower C10:1 levels (12.6%) had offspring with thicker sum of skinfolds (3.23 mm, 0.19, 6.27) than did women with abruptly increasing levels (87.4%) (p < 0.05). In conclusion, this study suggests that distinctive trajectories of C10, C10:1, and C12 acylcarnitine levels throughout pregnancy were significantly associated with neonatal anthropometry.

The role of maternal diet on offspring hyperinsulinaemia and adiposity after birth: a systematic review of randomised controlled trials

In utero diet may be directly related to the risk of fetal hyperinsulinaemia and offspring metabolic health. This review examines the relationship between maternal dietary exposures and sub-clinical fetal hyperinsulinaemia and neonatal adiposity. Articles were identified in MEDLINE, Web of Science, Cochrane Controlled Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, SCOPUS, and SPORTDiscus (September 2019-March 2021) using the preferred reporting items for systematic reviews and meta-analyses guidelines. PROSPERO registration ID CRD42020146453. Studies were selected by two independent reviewers. Randomised controlled trials (RCT) involving a dietary intervention with pregnant women (healthy pregnancy, gestational diabetes mellitus and obesity) and reporting fetal cord-blood insulin, c-peptide, glucose or adiposity estimates were included. One author extracted all information on main study characteristics and outcomes. Risk of bias was assessed using the Cochrane Collaboration's bias risk assessment tool. A total of 733 articles were identified. Fourteen articles from 11 RCTs (3614 participants) were included. Studies reviewed showed no specific effect of maternal diet on neonatal cord blood insulin, c-peptide or glucose levels. Infants born to mothers who followed a low glycaemic load (GL) had lower skin fold thickness compared to controls. Interventions that provided individualised nutrition counselling to women with obesity or previous infant born > 4 kg were also associated with lower adiposity. The studies reviewed suggest that lifestyle-based dietary interventions to improve glycaemia (low GL) have a protective effect against excess adiposity. Future studies should incorporate multi-modal interventions with dietary counselling to support lifestyle changes throughout gestation and include assessments of maternal insulin resistance at recruitment.

Assessment of Caffeine Consumption and Maternal Cardiometabolic Pregnancy Complications

IMPORTANCE

Women are recommended to limit caffeine consumption to less than 200 mg per day based on risks to fetal health. Impacts of caffeine on maternal health remain unclear.

OBJECTIVE

To determine whether caffeinated-beverage intake and plasma caffeine and paraxanthine are associated with cardiometabolic complications in pregnancy (ie, gestational diabetes [GDM], preeclampsia, and gestational hypertension [GH]).

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from a longitudinal pregnancy cohort study from the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singletons (2009-2013). This post hoc secondary analysis of 2802 pregnant women without major chronic conditions enrolled at 12 US clinical sites was completed in 2021. The final sample for caffeinated beverage analyses included 2583 women. After excluding women who did not consent to have their biospecimens stored for future research (n = 54), plasma caffeine analyses included 2529 women. Analyses of caffeine consumption and fasting cardiometabolic profiles included 319 women.

EXPOSURES

Daily total caffeine intake was estimated at 10 to 13 gestational weeks and 16 to 22 gestational weeks based on self-reported past week intake of caffeinated coffee, tea, soda, and energy drinks. Plasma caffeine and paraxanthine were measured in specimens collected at 10 to 13 weeks.

MAIN OUTCOMES AND MEASURES

Clinical diagnoses of GDM, preeclampsia, GH, glucose concentrations from GDM screening, and blood pressure were extracted from medical records.

RESULTS

Participants had a mean (SD) age of 28.1 (5.5) years and 422 participants (16.3%) were Asian/Pacific Islander women, 741 (28.9%) were Hispanic women, 717 (27.8%) were non-Hispanic Black women, and 703 (27.2%) were non-Hispanic White women. At 10 to 13 weeks, 1073 women (41.5%) reported consuming no caffeinated beverages, 1317 (51.0%) reported consuming 1 mg/d to 100 mg/d, 173 (6.7%) reported consuming 101 mg/d to 200 mg/d, and 20 (0.8%) reported consuming more than 200 mg/d. At 16 to 22 weeks, 599 women (23.6%) reported consuming no caffeinated beverages, 1734 (68.3%) reported consuming 1 mg/d to 100 mg/d, 186 (7.3%) reported consuming 101 mg/d to 200 mg/d, and 20 (0.8%) reported consuming more than 200 mg/d caffeinated beverages. Intake at 16 to 22 weeks was associated with lower GDM risk and lower glucose concentrations (1 mg/d to 100 mg/d vs none: relative risk, 0.53 [95% CI, 0.35 to 0.80]; β, -2.7 mg/dL [95% CI, -5.4 mg/dL to 0 mg/dL]) and lower C-reactive protein and C-peptide concentrations and favorable lipid profiles. Total plasma caffeine and paraxanthine at 10 to 13 weeks was inversely associated with glucose (quartile 4 vs quartile 1: β = -3.8 mg/dL [95% CI, -7.0 mg/dL to -0.5 mg/dL]; trend of P = .01). No associations were observed with preeclampsia or GH.

CONCLUSIONS AND RELEVANCE

In this cohort study, second trimester caffeinated beverage intake within current recommendations was associated with lower GDM risk, but not preeclampsia or GH. These findings may be reassuring for women with moderate caffeine intake.

Diabetes in pregnancy 100 years after the discovery of insulin: Hot topics and open questions to be addressed in the coming years

By making it possible for women with diabetes to achieve their family planning goals, the discovery of insulin ushered in the field of diabetes in pregnancy. The ensuing century has witnessed tremendous advances, with clinical focus on preconception planning and maternal glycemic control making successful pregnancy an achievable goal. Currently, the global epidemic of overweight/obesity has led to maternal hyperglycemia now affecting one in every six pregnancies worldwide, prompting intense research interest. Topics of particular interest include (i) the optimal approach to diagnosing gestational diabetes mellitus (GDM); (ii) the emergence of GDM as a chronic metabolic disorder identifying future risk of non-communicable disease; (iii) the transgenerational impact of maternal glycemia as per the Developmental Origins of Health and Disease; and (iv) the application of new technology for optimizing clinical management. These topics have raised exciting questions such as (i) whether the treatment of diabetes in pregnancy can impact growth/development in childhood, (ii) whether GDM can be prevented, and (iii) whether the diagnosis of GDM could facilitate the prevention of type 2 diabetes and cardiovascular disease. Indeed, this field may be on the precipice of a golden era of new concepts and evidence to optimize the health of mother and child.

Does exercise during pregnancy impact organs or structures of the maternal-fetal interface?

Exercise during pregnancy has been shown to be associated with improved health outcomes both during and after pregnancy for mother and fetus across the lifespan. Increasing physical activity and reducing sedentary behaviour during pregnancy have been recommended by many researchers and clinicians-alike. It is thought that the placenta plays a central role in mediating any positive or negative pregnancy outcomes. The positive outcomes obtained through prenatal exercise are postulated to result from exercise-induced regulation of maternal physiology and placental development. Considerable research has been performed to understand the placenta's role in pregnancy-related diseases, such as preeclampsia, fetal growth restriction, and gestational diabetes mellitus. However, little research has examined the potential for healthy lifestyle and behavioural changes to improve placental growth, development, and function. While the placenta represents the critical maternal-fetal interface responsible for all gas, nutrient, and waste exchange between the mother and fetus, the impact of exercise during pregnancy on placental biology and function is not well known. This review will focus on prenatal exercise and its promising influence on the structures of the maternal-fetal interface, with particular emphasis on the placenta. Potential molecular mechanistic hypotheses are presented to aid future investigations of prenatal exercise and placental health.

Vegetarian diets during pregnancy, and maternal and neonatal outcomes

BACKGROUND

Vegetarian diets are becoming increasingly popular in the USA. Limited research has examined the health consequences of vegetarian diets during pregnancy. We comprehensively examined associations of vegetarianism during pregnancy with maternal and neonatal outcomes.

METHODS

We used data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development's Fetal Growth Studies-Singletons, a prospective multi-site cohort of 1948 low-risk pregnant women of four races/ethnicities (White, Black, Hispanic, Asian/Pacific Islander) in the USA (2009-2013). Vegetarianism was self-reported and also defined based on dietary patterns measured using a self-administered first-trimester food-frequency questionnaire (full [lacto-ovo and vegan], pesco-, semi- and non-vegetarians). Neonatal outcomes included birthweight and neonatal anthropometric measures, small for gestational age, small for gestational age with neonatal morbidity and preterm delivery. Maternal outcomes included gestational weight gain, gestational diabetes, hypertensive disorders of pregnancy and gestational anaemia.

RESULTS

Ninety-nine (6.2%) women self-reported being vegetarian. The diet-based definition identified 32 (2.0%) full vegetarians, 7 (0.6%) pesco-vegetarians and 301 (17.6%) semi-vegetarians. Neonates of diet-based full vegetarians had higher odds of being small for gestational age [adjusted odds ratio (ORadj) = 2.51, 95% confidence interval: 1.01, 6.21], but not of being small for gestational age with a postnatal morbidity. Full vegetarians had marginally increased the odds of inadequate second-trimester gestational weight gain (ORadj = 2.24, 95% confidence interval: 0.95, 5.27).

CONCLUSION

Vegetarian diets during pregnancy were associated with constitutionally smaller neonatal size, potentially via the mothers' reduced gestational weight gain. Notably, vegetarianism was not associated with small-for-gestational-age-related morbidities or other adverse maternal outcomes.

Potential Role of Insulin Growth-Factor-Binding Protein 2 as Therapeutic Target for Obesity-Related Insulin Resistance

Evidence from observational and in vitro studies suggests that insulin growth-factor-binding protein type 2 (IGFBP2) is a promising protein in non-communicable diseases, such as obesity, insulin resistance, metabolic syndrome, or type 2 diabetes. Accordingly, great efforts have been carried out to explore the role of IGFBP2 in obesity state and insulin-related diseases, which it is typically found decreased. However, the physiological pathways have not been explored yet, and the relevance of IGFBP2 as an important pathway integrator of metabolic disorders is still unknown. Here, we review and discuss the molecular structure of IGFBP2 as the first element of regulating the expression of IGFBP2. We highlight an update of the association between low serum IGFBP2 and an increased risk of obesity, type 2 diabetes, metabolic syndrome, and low insulin sensitivity. We hypothesize mechanisms of IGFBP2 on the development of obesity and insulin resistance in an insulin-independent manner, which meant that could be evaluated as a therapeutic target. Finally, we cover the most interesting lifestyle modifications that regulate IGFBP2, since lifestyle factors (diet and/or physical activity) are associated with important variations in serum IGFBP2.

The Influence of Gestational Diabetes Mellitus upon the Selected Parameters of the Maternal and Fetal System of Insulin-Like Growth Factors (IGF-1, IGF-2, IGFBP1-3)-A Review and a Clinical Study

BACKGROUND

Gestational diabetes mellitus (GDM), defined as impaired glucose tolerance with onset or first recognition in pregnancy, increases the risk of not only maternal but also fetal and neonatal complications. Given the structural similarity of insulin-like growth factors with insulin and participation of components of the insulin-like growth factor system in glucose homeostasis, we hypothesized that the IGF axis is involved in the development of GDM complications or its pathogenesis. The aim of this study was to evaluate the effect of GDM on the selected parameters of the insulin-like growth factors (IGF-1, IGF-2, IGFBP1-3) in the maternal and fetal blood.

METHODS

The clinical material of this case-control study included 109 pregnant women and their offspring. The study group (n = 120) consisted of 60 patients with diagnosed gestational diabetes and their newborn babies. The control group (n = 98) comprised 49 healthy parturients and their offspring. We measured the concentrations of IGF-1, IGF-2, IGFBP-1, IGFBP-2, IGFBP-3, insulin and glucose made by the ELISA method in peripheral blood serum in patients suffering from GDM and pregnant women without GDM, and in the umbilical cord blood of newborn babies born to them.

RESULTS

The analysis of concentrations of IGF-1, -2 and IGFBP-3 in peripheral blood as well as umbilical cord blood did not demonstrate a statistically significant difference between the study group and the control group. Significantly lower concentration of IGFBP-1, IGFBP-2 in peripheral blood and in umbilical cord blood was detected in the study group in comparison to the control group. A statistically positive correlation between the concentration of IGF-1 in umbilical cord serum of newborn babies born to women with gestational diabetes and the length of a baby after its birth was observed.

CONCLUSIONS

Gestational diabetes mellitus does not significantly affect the concentrations of IGF-1, -2, IGFBP-3 in the peripheral blood and umbilical cord blood, but has the greatest influence on maternal and fetal IGFBP-2 concentrations. A positive correlation between the concentration of IGF-1 in umbilical cord blood and the length of a newborn suggests an influence of IGF-1 on the process of fetal development.

Adipokines in early and mid-pregnancy and subsequent risk of gestational diabetes: a longitudinal study in a multiracial cohort

INTRODUCTION

Several adipokines are implicated in the pathophysiology of gestational diabetes mellitus (GDM), however, longitudinal data in early pregnancy on many adipokines are lacking. We prospectively investigated the association of a panel of adipokines in early and mid-pregnancy with GDM risk.

RESEARCH DESIGN AND METHODS

Within the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singletons cohort (n=2802), a panel of 10 adipokines (plasma fatty acid binding protein-4 (FABP4), chemerin, interleukin-6 (IL-6), leptin, soluble leptin receptor (sOB-R), adiponectin, omentin-1, vaspin, and retinol binding protein-4) were measured at gestational weeks (GWs) 10-14, 15-26, 23-31, and 33-39 among 107 GDM cases (ascertained on average at GW 27) and 214 non-GDM controls. Conditional logistic regression was used to estimate ORs of each adipokine and GDM, controlling for known GDM risk factors including pre-pregnancy body mass index.

RESULTS

Throughout pregnancy changes in chemerin, sOB-R, adiponectin, and high-molecular-weight adiponectin (HMW-adiponectin) concentrations from 10-14 to 15-26 GWs were significantly different among GDM cases compared with non-GDM controls. In early and mid-pregnancy, FABP4, chemerin, IL-6 and leptin were positively associated with increased GDM risk. For instance, at 10-14 GWs, the OR comparing the highest versus lowest quartile (ORQ4-Q1) of FABP4 was 3.79 (95% CI 1.63 to 8.85). In contrast, in both early and mid-pregnancy adiponectin (eg, ORQ4-Q1 0.14 (0.05, 0.34) during 10-14 GWs) and sOB-R (ORQ4-Q1 0.23 (0.11, 0.50) during 10-14 GWs) were inversely related to GDM risk. At 10-14 GWs a model that included conventional GDM risk factors and FABP4, chemerin, sOB-R, and HMW-adiponectin improved the estimated prediction (area under the curve) from 0.71 (95% CI 0.66 to 0.77) to 0.77 (95% CI 0.72 to 0.82).

CONCLUSIONS

A panel of understudied adipokines including FABP4, chemerin, and sOB-R may be implicated in the pathogenesis of GDM with significant associations detected approximately 10-18 weeks before typical GDM screening.

Downregulation of microRNA-873 attenuates insulin resistance and myocardial injury in rats with gestational diabetes mellitus by upregulating IGFBP2

Gestational diabetes mellitus (GDM) is a metabolic disorder characterized by insulin resistance, and patients with GDM have a higher risk of cardiovascular disease. Multiple microRNAs (miRNAs) are reported to be involved in the regulation of myocardial injury. Moreover, miR-873 was predicted to target insulin-like growth factor binding protein 2 (IGFBP2) through bioinformatic analysis, which was further confirmed using a luciferase assay. Thus, our objective was to assess whether microRNA-873 (miR-873) affects insulin resistance and myocardial injury in an established GDM rat model. The GDM rats were treated with miR-875 mimic or inhibitor or IGFBP2 siRNA. The effects of miR-875 and IGFBP2 on the cardiac function, insulin resistance, and myocardial injury were evaluated by hemodynamic measurements, determination of biochemical indices of myocardium and serum, and insulin homeostatic model assessment. The results indicated that downregulation of miR-873 upregulated the expression of IGFBP2 and promoted the activation of phosphatidylinositol-3 kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) axis. With downregulation of miR-873 in GDM rats, the cardiac function was improved and the myocardial apoptosis was inhibited, coupled with elevated activity of superoxide dismutase, carbon monoxide synthase, and the nitric oxide content. In addition, the inhibition of miR-873 in GDM rats modulated the insulin resistance and reduced myocardial apoptosis. Overall, the data showed that inhibition of miR-873 by targeting IGFBP2 may regulate the insulin resistance and curtail myocardial injury in GDM rats through activating the PI3K/AKT/mTOR axis, thus providing a potential means of impeding the progression of GDM.

Glycaemic status during pregnancy and longitudinal measures of fetal growth in a multi-racial US population: a prospective cohort study

BACKGROUND

The timepoint at which fetal growth begins to differ by maternal glycaemic status is not well understood. To address this lack of data, we examined gestational diabetes, impaired glucose tolerance, and early pregnancy glucose concentrations in relation to fetal growth trajectories.

METHODS

This cohort study included 2458 pregnant women from the NICHD Fetal Growth Studies-Singletons study, which took place between 2009 and 2013. Women were recruited from 12 clinical centres in the USA. Women aged 18-40 years without major chronic conditions when entering pregnancy were included and those with records of neither glucose screening test or glucose tolerance test were excluded from the study. Women were enrolled at gestational weeks 8-13 and randomly assigned to four ultrasonogram schedules (Group A; weeks 16, 24, 30, 34; Group B: weeks 18, 26, 31, 35, 39; Group C: weeks 20, 28, 32, 36; Group D: weeks 22, 29, 33, 37, 41) to capture weekly fetal growth. Gestational diabetes, impaired glucose tolerance, and normal glucose tolerance were defined by medical record review. Glucose was measured in a subsample of women at weeks 10-14. We modelled fetal growth trajectories using linear mixed models with cubic splines. This study is registered with ClinicalTrials.gov, NCT00912132.

FINDINGS

Of the 2458 women included in this study, 107 (4·4%) had gestational diabetes, 118 (4·8%) had impaired glucose tolerance, and 2020 (82·2%) had NGT. 213 women were excluded from the main analysis. The cohort with gestational diabetes was associated with a larger estimated fetal weight that started at week 20 and was significant at week 28-40 (at week 37: 3061 g [95% CI 2967-3164] for women with gestational diabetes vs 2943 g [2924-2962] for women with normal glucose tolerance, adjusted p=0·02). In addition, glucose levels at weeks 10-14 were positively associated with estimated fetal weight starting at week 23 and the association became significant at week 27 (at week 37: 3073 g [2983-3167] in the highest tertile vs 2853 g [2755-2955] in the lowest tertile, adjusted p=0·0009.

INTERPRETATION

Gestational diabetes was associated with a larger fetal size that started at week 20 and became significant at gestational week 28. Efforts to mitigate gestational diabetes-related fetal overgrowth should start before 24-28 gestational weeks, when gestational diabetes is typically screened for in the USA.

FUNDING

National Institutes of Health.

Plasma Prolactin and Progesterone Levels and the Risk of Gestational Diabetes: A Prospective and Longitudinal Study in a Multiracial Cohort

Objective: Prolactin and progesterone are implicated in glucose homeostasis in and outside of pregnancy. However, their associations with gestational diabetes (GDM) risk were not well-understood. This study investigates this question in a prospective and longitudinal cohort. Methods: This is a nested case-control study of 107 incident GDM cases and 214 matched non-GDM controls within the NICHD Fetal Growth Studies-Singleton Cohort. Blood samples were collected at gestational weeks 10-14, 15-26, 23-31, and 33-39. The odds ratios (OR) of GDM were estimated using conditional logistic regression. The longitudinal changes in prolactin and progesterone were estimated using linear mixed-effects models. Results: Compared to controls, cases have significantly higher prolactin levels at weeks 10-14 (median: 50.4 vs. 42.1 ng/mL), and significantly lower progesterone levels at weeks 10-14 (median: 109.4 vs. 126.5 nmol/L). Prolactin levels at weeks 10-14 were significantly and positively associated with GDM risk; the adjusted ORs across increasing quartiles were 1.00, 1.13, 1.80, 2.33 (p-trend = 0.02). A similar but slightly attenuated association was observed at weeks 15-26 (p-trend = 0.05). Progesterone was not associated with GDM risk at either time points. Longitudinal changes in prolactin and progesterone between the first two visits were not associated with GDM risk. In addition, prolactin was significantly and positively associated with insulin and C-peptide levels at weeks 10-14, and significantly and inversely associated with C-peptide levels at weeks 15-26; progesterone was significantly and inversely associated with glucose and insulin levels. Conclusions: This study provided the first prospective evidence of a positive association between prolactin levels in early pregnancy and GDM risk.

Pregnancy-associated plasma protein-A2 levels are increased in early-pregnancy gestational diabetes: a novel biomarker for early risk estimation

AIM

To determine whether pregnancy-associated plasma protein-A2 levels are increased in early pregnancies complicated by gestational diabetes and whether gestation age influences levels. The possible use of pregnancy-associated plasma protein-A2 as a pre-screening biomarker to reduce the need for performing oral glucose tolerance tests in pregnant women was also investigated.

METHODS

Pregnant women were diagnosed with gestational diabetes in early pregnancy after a 2-hour 75 g oral glucose tolerance test in the catchment area of Skåne University Hospital, Lund, Sweden during 2011-2015 (n = 99). Age- and BMI-matched pregnant women without diabetes were recruited at similar gestational ages from maternal healthcare centres in the same geographical area during 2014-2015 to act as controls (n = 100). Circulating pregnancy-associated plasma protein-A2 was analysed in participant serum using commercially available enzyme-linked immunosorbent assay kits.

RESULTS

Circulating pregnancy-associated plasma protein-A2 was increased in women diagnosed with gestational diabetes [13.5 (9.58-18.8) ng/ml] compared with controls [8.11 (5.74-11.3) ng/ml; P < 0.001]. Pregnancy-associated plasma protein-A2 was associated with gestational diabetes independent of age, BMI, C-peptide and adiponectin (P < 0.001). Pregnancy-associated plasma protein-A2 as a pre-screening biomarker to identify women at a decreased risk of gestational diabetes resulted in a negative predictive value of 99.7%, with a sensitivity of 96% and a specificity of 30% at a cut-off level of 6 ng/ml.

CONCLUSIONS

This is the first study to show increased pregnancy-associated plasma protein-A2 levels in gestational diabetes. Pregnancy-associated plasma protein-A2 also shows promise as a pre-screening biomarker with the potential to reduce the need for performing oral glucose tolerance tests in early pregnancy. Future prospective cohort studies in a larger group of both high- and low-risk women are, however, needed to further confirm this observation.

Plasma phospholipid n-3 and n-6 polyunsaturated fatty acids in relation to cardiometabolic markers and gestational diabetes: A longitudinal study within the prospective NICHD Fetal Growth Studies

BACKGROUND

Despite dietary recommendations of polyunsaturated fatty acids (PUFAs) for cardiometabolic health, n-3 and n-6 PUFAs and their interplay in relation to diabetes risk remain debated. Importantly, data among pregnant women are scarce. We investigated individual plasma phospholipid n-3 and n-6 PUFAs in early to midpregnancy in relation to subsequent risk of gestational diabetes mellitus (GDM).

METHODS AND FINDINGS

Within the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singleton Cohort (n = 2,802), individual plasma phospholipid n-3 and n-6 PUFAs levels were measured at gestational weeks (GWs) 10-14, 15-26, 23-31, and 33-39 among 107 GDM cases (ascertained on average at GW 27) and 214 non-GDM controls. Conditional logistic regression was used, adjusting for major risk factors for GDM. After adjusting for covariates, individual n-3 eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) were inversely correlated with insulin-resistance markers, whereas individual n-6 dihomo-gamma-linolenic acid (DGLA) was positively correlated with insulin-resistance markers. At GW 15-26, a standard deviation (SD) increase in total n-3 PUFAs and individual n-3 DPA was associated with a 36% (adjusted odds ratio 0.64; 95% CI 0.42-0.96; P = 0.042) and 33% (0.67; 95% CI 0.45-0.99; P = 0.047) lower risk of GDM, respectively; however, the significance did not persist after post hoc false-discovery rate (FDR) correction (FDR-corrected P values > 0.05). Associations between total n-6 PUFAs and GDM were null, whereas associations with individual n-6 PUFAs were differential. Per SD increase, gamma-linolenic acid (GLA) at GWs 10-14 and DGLA at GWs 10-14 and 15-26 were significantly associated with a 1.40- to 1.95-fold higher risk of GDM, whereas docosatetraenoic acid (DTA) at GW 15-26 was associated with a 45% (0.55; 95% CI 0.37-0.83) lower risk of GDM (all FDR-corrected P values < 0.05). Null associations were observed for linoleic acid (LA) in either gestational window in relation to risk of GDM. Women with high (≥median) n-3 PUFAs and low (<median) n-6 PUFAs levels had a 64% (95% CI 0.14-0.95; P value = 0.039) lower risk of GDM versus women with low n-3 and high n-6 PUFAs. Limitations include the inability to distinguish between exogenous and endogenous influences on circulating PUFA levels and the lack of causality inherent in observational studies.

CONCLUSIONS

Our findings may suggest a potential role of primarily endogenously metabolized plasma phospholipid n-6 PUFAs including GLA, DGLA, and DTA in early to midpregnancy in the development of GDM. Null findings on primarily diet-derived n-3 EPA and DHA and n-6 LA do not provide strong evidence to suggest a beneficial role in prevention of GDM, although not excluding the potential benefit of EPA and DHA on glucose-insulin homeostasis given the inverse associations with insulin-resistance markers. Our findings highlight the importance of assessing individual circulating PUFAs to investigate their distinct pathophysiologic roles in glucose homeostasis in pregnancy.

Insulin-like growth factor axis in pregnancy and gestational diabetes mellitus

The insulin-like growth factor (IGF) is involved in the regulation of growth and metabolism. The aim of this study was to determine selected parameters of IGF system at systemic and local levels [subcutaneous (SAT) and visceral adipose tissue (VAT)] to assess its possible role in gestational diabetes mellitus (GDM). 37 pregnant women (21 with GDM and 16 without GDM) and 15 age-matched non-pregnant females were included in the study. Blood samples were taken in 28-32 and 36-38 weeks of gestation and 6-12 months after delivery. SAT and VAT samples were obtained during delivery or surgery. Compared with non-pregnant women, serum IGF-1 and IGFBP-3 were increased in both groups of pregnant women. IGF-2 was elevated only in GDM women from 36 weeks of gestation culminating 6 months after delivery (p=0.003). Serum IGFBP-3 was increased and IGFBP-4 decreased in GDM women vs. pregnant women without GDM during the whole study (IGFBP-3: p?0.001 for GDM vs. non-GDM; IGFBP-4: p=0.004 for GDM vs. non-GDM). Pregnant women with GDM had decreased mRNA expression of IGF-1, IGF-1R and IGF-2R and IGFBP-4 in VAT and IGF-1R in SAT compared to pregnant women without GDM. Changes in local activity of IGF are associated with the development of GDM.

Maternal adipokines longitudinally measured across pregnancy and their associations with neonatal size, length, and adiposity

BACKGROUND/OBJECTIVES

Maternal obesity impacts fetal growth as early as second trimester of pregnancy, yet little is known about the molecular mechanisms involved. We aimed to examine associations between maternal adipokines throughout pregnancy and neonatal size by prepregnancy obesity status.

METHODS

In a prospective cohort of 2802 U.S. pregnant women from the NICHD Fetal Growth Studies-Singleton Cohort (2009-2013), biospecimens were analyzed in a matched case-control subset of 321 women. Blood was collected at 10-14, 15-26 (fasting), 23-31, and 33-39 gestational weeks. Plasma leptin and soluble leptin receptor (sOB-R) and total and high-molecular-weight (HMW)-adiponectin were measured. Free leptin was calculated as leptin/sOB-R. Birthweight was abstracted from medical records. Neonatal length and skinfolds were measured.

RESULTS

Leptin and sOB-R in late pregnancy tended to be positively and negatively associated with neonatal length, respectively, while free leptin throughout pregnancy tended to be positively associated with length. Free leptin associations with neonatal length were differential by obesity (i.e., inversely among women without obesity and positively among women with obesity). A per unit increase in free leptin at 33-39 weeks was associated with a shorter neonatal length by -0.55 cm (95%CI, -0.83, -0.28) in women without obesity and longer length by 0.49 cm (95%CI, 0.34, 0.65) in women with obesity. HMW-adiponectin at 33-39 weeks was inversely associated with neonatal length (β = -1.29 cm; 95%CI, -1.74, -0.85) and skinfold thickness (β = -1.46 mm; 95%CI, -1.58, -0.56) among women with obesity. Free leptin across pregnancy tended to be negatively associated with neonatal skinfold thickness among women without obesity, while free leptin in early pregnancy was positively associated with skinfold thickness.

CONCLUSIONS

Maternal adipokines were associated with multiple pathways that influence neonatal size including length and adiposity, which differed in timing across pregnancy and by prepregnancy obesity. These findings provide new potential insights into mechanisms and timing by which maternal obesity may impact fetal growth.

Effects of gestational diabetes mellitus on stereological parameters and extravillous trophoblast cells of placenta compared to the control group

The quantitative changes of extravillous trophoblast cells (EVTs) in placenta of gestational diabetes mellitus (GDM) patients were investigated compared to healthy controls using stereological methods. The volumetric parameters of the placenta and EVTs were estimated using Cavalieri's principle and Physical Disector stereological methods. The placental volume and weight in the GDM group increased compared to the control group (p < .05). The difference in the total volume of intervillous space and blood vessels of the placenta between GDM and control groups was statistically significant (p < .05). In addition, there was a significant difference in the volume density of blood vessels and syncytiotrophoblast between the GDM group and the control group (p < .05). The total volume of the EVTs, nucleus and cytoplasm diameter, volume of the nucleus and cytoplasm, nucleus to cytoplasm ratio (N/C) of EVTs and the total number of EVTs per unit volume of the placenta in the GDM group showed a significant increase compared to the controls (p < .05). Impact statement What is already known on this subject? It is reported that extravillous trophoblast cells (EVTs) played an important role in pregnancy complications. There are limited studies on the quantitative changes of EVTs in the placental bed of GDM patients. What do the results of this study add? The results showed that volumetric parameters and number of EVTs were significantly altered in GDM placentas. These changes can be associated with disturbances in trophoblastic invasion in GDM pregnancies and may affect the development and survival of the embryo. What are the implications of these findings for clinical practice and/or further research? In the present study, there is a new insight to placenta structure that probably could be useful to understanding possible mechanisms of pregnancy complications and the achievement of new therapeutic strategies. Further investigation on the molecular biology of these cells in pregnancy complications will be needed to clarify this hypothesis.

Insulin-Like Growth Factor Axis Biomarkers and Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

The insulin-like growth factor (IGF) axis has been implicated in glucose homeostasis. It is plausible to hypothesize that the IGF axis is involved in the development of gestational diabetes mellitus (GDM). In a systematic review of the evidence on IGF axis biomarkers in relation to GDM, we searched the PubMed and EMBASE for publications up to May 31, 2018, on the associations of circulating IGF axis biomarkers with GDM. Eligible studies must meet the pre-specified quality assessment criteria. Meta-analyses were conducted where there were at least three studies on the same biomarker at the same gestational age window-early (<20 weeks), mid (20-29 weeks), or late (30+ weeks) gestation. Twelve studies were included (484 GDM, 1755 euglycemic pregnancies). Meta-analyses showed that GDM was consistently associated with higher IGF-I concentrations in mid-gestation (six studies) and late gestation (six studies). There were only two studies on IGF-I in early gestation and GDM with inconsistent findings. GDM was associated with lower IGFBP-2 concentrations in early, mid-, or late gestation, according to data from one or two studies. GDM was associated with higher IGFBP-3 concentrations in late gestation according to a meta-analysis of five studies. There was no association with GDM for IGFBP-3 in early or mid-gestation, according to data from one study. Other IGF axis biomarkers (IGF-II, IGFBP-1,-4,-5-6, and -7) showed no or inconsistent associations, and the data at early gestation were scanty or absent. Available evidence is suggestive but inconclusive concerning whether the IGF axis is involved in the development of GDM. More studies on IGF axis biomarkers in early gestation are warranted. If a specific IGF axis molecule is proven to be involved in the development of GDM, this may point to a new molecular target for designing interventions to reduce the incidence of GDM.

Central Obesity Increases the Risk of Gestational Diabetes Partially Through Increasing Insulin Resistance

OBJECTIVE

This study examined the associations of central obesity measures, waist to hip ratio (WHR) and waist circumference (WC), in early pregnancy with subsequent risk of gestational diabetes mellitus (GDM) and evaluated the potential mediating role of insulin resistance markers.

METHODS

Within the prospective Pregnancy Environment and Lifestyle Study cohort of 1,750 women, WC and hip circumference were measured at gestational weeks 10 to 13. In a nested case-control study within the cohort, 115 GDM cases and 230 controls had fasting serum insulin, homeostatic model assessment of insulin resistance (HOMA-IR), and adiponectin measurements at gestational weeks 16 to 19. Poisson and conditional logistic regression models were used, adjusting for established risk factors for GDM, including prepregnancy overweight or obesity.

RESULTS

For women with WHR < 0.85, one or more established risk factors increased GDM risk 1.99-fold (95% CI: 0.99-4.02). For women with WHR ≥ 0.85 but no established risk factors, GDM risk increased 2.41-fold (95% CI: 1.14-5.06), and in those with established risk factors it increased 6.22-fold (95% CI: 3.49-11.10). Similar but attenuated results were observed for WC ≥ 88 cm. Insulin, HOMA-IR, and adiponectin levels mediated the WHR-GDM association by 9% to 11%; corresponding mediation proportions for the WC-GDM association were 35% to 41% (all P  < 0.04).

CONCLUSIONS

Central obesity in early pregnancy represented a high-risk phenotype for GDM independent of other risk factors, including overweight or obesity, and may inform early screening and prevention strategies.

Comparison of serum concentrations of humanin in women with and without gestational diabetes mellitus

Humanin (MT-RNR2) is an endogenous polypeptide that is involved in many diseases, including T2DM. Gestational diabetes mellitus (GDM) is defined as hyperglycemia during pregnancy. The aim of this study was to evaluate serum humanin levels in women with or without GDM and to elucidate possible correlations with anthropometric parameters, metabolic parameters and the incidence of GDM. Eighty-four women with GDM and 73 control women were enrolled in this study. The clinical and biochemical parameters of all subjects were determined. Serum humanin levels were measured by an ELISA. Serum humanin levels were significantly lower in women with GDM than in control women. Moreover, humanin levels were significantly negatively correlated with the presence of GDM, body weight, BMI at 24 weeks of gestation, TG, FPG, 1 hPG, 2 hPG, FINS, and HOMA-IR. In contrast, humanin levels were significantly positively correlated with FT3 and FT4. A binary logistic analysis showed that humanin levels were associated with the incidence of GDM. Additional follow-up studies are needed to highlight whether and how decreased humanin levels play an important role in GDM.

Hyperglycemia in pregnancy and its implications for a woman's future risk of cardiovascular disease

It is well established that gestational diabetes mellitus (GDM) identifies a population of women who are at risk of ultimately developing type 2 diabetes (T2DM) later in life. Moreover, this relationship extends across the full spectrum of hyperglycemia in pregnancy, with lesser degrees of gestational dysglycemia identifying a proportionate gradient of future risk of T2DM. Importantly, a growing body of evidence suggests that an analogous relationship exists between hyperglycemia in pregnancy and a woman's long-term risk of cardiovascular disease (CVD), as well. Indeed, as compared to their peers, woman who had GDM have a higher risk of major cardiovascular events, which first manifests within the first decade after the index pregnancy. Although the absolute incidence of such events remains low in young women of child-bearing age, the identification of future risk of CVD at this early point in its natural history may provide the unique opportunity for timely intervention and ideally disease prevention. Thus, in this review, we discuss the emerging concept of hyperglycemia in pregnancy as an indicator of the future risk of CVD in young women and its implications for research and clinical practice.

The insulin like growth factor and binding protein family: Novel therapeutic targets in obesity & diabetes

Background

Recent changes in nutrition and lifestyle have provoked an unprecedented increase in the prevalence of obesity and metabolic disorders. Recognition of the adverse effects on health has prompted intense efforts to understand the molecular determinants of insulin sensitivity and dysglycemia. In many respects, actions of insulin-like growth factors (IGFs) mirror those of insulin in metabolic regulation. Unlike insulin, however, the bioactivity of IGFs is regulated by a family of seven high-affinity binding proteins (IGFBPs) which confer temporospatial modulation with implications for metabolic homeostasis. In addition, evidence is accumulating that IGF-independent actions of certain of the IGFBPs can directly modulate insulin sensitivity.

Scope of review

In this review, we discuss the experimental data indicating a critical role for IGF/IGFBP axis in metabolic regulation. We highlight key discoveries through which IGFBPs have emerged as biomarkers or putative therapeutic targets in obesity and diabetes.

Major conclusions

Growing evidence suggests that several components of the IGF-IGFBP system could be explored for therapeutic potential in metabolic disorders. Both IGFBP-1 and IGFBP-2 have been favorably linked with insulin sensitivity in humans and preclinical data implicate direct involvement in the molecular regulation of insulin signaling and adiposity respectively. Further studies are warranted to evaluate clinical translation of these findings.

Role of IGF-binding proteins in regulating IGF responses to changes in metabolism

The IGF-binding protein family contains six members that share significant structural homology. Their principal function is to regulate the actions of IGF1 and IGF2. These proteins are present in plasma and extracellular fluids and regulate access of both IGF1 and II to the type I IGF receptor. Additionally, they have functions that are independent of their ability to bind IGFs. Each protein is regulated independently of IGF1 and IGF2, and this provides an important mechanism by which other hormones and physiologic variables can regulate IGF actions indirectly. Several members of the family are sensitive to changes in intermediary metabolism. Specifically the presence of obesity/insulin resistance can significantly alter the expression of these proteins. Similarly changes in nutrition or catabolism can alter their synthesis and degradation. Multiple hormones such as glucocorticoids, androgens, estrogen and insulin regulate IGFBP synthesis and bioavailability. In addition to their ability to regulate IGF access to receptors these proteins can bind to distinct cell surface proteins or proteins in extracellular matrix and several cellular functions are influenced by these interactions. IGFBPs can be transported intracellularly and interact with nuclear proteins to alter cellular physiology. In pathophysiologic states, there is significant dysregulation between the changes in IGFBP synthesis and bioavailability and changes in IGF1 and IGF2. These discordant changes can lead to marked alterations in IGF action. Although binding protein physiology and pathophysiology are complex, experimental results have provided an important avenue for understanding how IGF actions are regulated in a variety of physiologic and pathophysiologic conditions.

Plasma concentrations of lipids during pregnancy and the risk of gestational diabetes mellitus: A longitudinal study

BACKGROUND

Abnormal lipid profiles have been associated with gestational diabetes mellitus (GDM), but studies with longitudinal measures of lipids throughout pregnancy are sparse. The aim of the present study was to characterize longitudinal changes in lipid profiles throughout pregnancy and prospectively examine the associations of plasma lipid concentrations with risk of GDM.

METHODS

This study was a nested case-control study including 107 GDM cases and 214 matched non-GDM controls from participants in the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies - Singleton cohort. Blood samples were collected longitudinally at Gestational Weeks (GW) 10-14, 15-26 (fasting sample), 23-31, and 33-39. Plasma concentrations of triglycerides, total cholesterol, and high-density lipoprotein cholesterol (HDL-C) were measured by enzymatic assays. Low-density lipoprotein cholesterol (LDL-C) was calculated using Friedewald's formula.

RESULTS

Plasma triglycerides, total cholesterol, and LDL-C increased as pregnancy progressed. At GW 10-14, the adjusted odds ratios (aORs) of GDM comparing the highest versus lowest quartile were 3.15 (95% confidence interval [CI] 1.38-7.15; P _trend  = 0.002) for triglycerides and 0.44 (95% CI 0.18-1.09; P _trend  = 0.045) for HDL-C. At GW 15-26, the aORs were 6.57 (95% CI 2.25-19.17; P _trend  = 0.001) for triglycerides and 0.23 (95% CI 0.08-0.63; P _trend  = 0.005) for HDL-C. No significant associations were observed for total cholesterol and LDL-C concentrations with risk of GDM.

CONCLUSIONS

Higher plasma triglyceride and lower HDL-C concentrations in early and mid-pregnancy were significantly associated with a greater risk of GDM. Total cholesterol and LDL-C concentrations during pregnancy were not significantly associated with GDM risk.

A prospective and longitudinal study of plasma phospholipid saturated fatty acid profile in relation to cardiometabolic biomarkers and the risk of gestational diabetes

Background

Data on saturated fatty acids (SFAs) in relation to metabolic function and glucose homeostasis remain controversial. Such data are lacking among pregnant women.

Objective

We prospectively investigated objectively measured individual and subclasses of plasma phospholipid SFAs throughout pregnancy in relation to cardiometabolic markers and gestational diabetes mellitus (GDM) risk.

Design

Within the National Institute of Child Health and Human Development Fetal Growth Studies-Singleton Cohort of 2802 singleton pregnancies, 107 GDM cases were ascertained via medical record review and matched to 214 non-GDM controls on age, race/ethnicity, and gestational week (GW) at blood collection. Individual plasma phospholipid SFA concentrations were repeatedly measured throughout pregnancy at GWs 10-14, 15-26, 23-31, and 33-39 and also grouped into subclasses of even- or odd-chain SFAs.

Results

From GW 10, even-chain SFA concentrations were significantly higher among women who later developed GDM, whereas odd-chain SFAs were significantly lower among GDM cases compared with controls. At GWs 10-14, the SFA palmitic acid (16:0) was positively associated with impaired insulin resistance and cardiometabolic markers and the risk of GDM [adjusted OR comparing the highest with the lowest quartile (aORQ4-Q1): 4.76; 95% CI: 1.72, 13.10; P-trend = 0.001]. In contrast, odd-chain SFAs were inversely related to the previously mentioned markers and GDM risk [aORQ4-Q1 for pentadecanoic acid (15:0): 0.32; 95% CI: 0.11, 0.92; P-trend = 0.025; for heptadecanoic acid (17:0): 0.20; 95% CI: 0.07, 0.58; P-trend = 0.003]. Women with high (median or greater) even-chain SFA concentrations and low (less than median) odd-chain SFAs had a 9.43-fold (95%: CI 3.26-, 27.30-fold) increased risk compared with women with low even-chain and high odd-chain SFA concentrations. Similar results were observed at GWs 15-26.

Conclusions

The study provided one of the first lines of evidence suggesting that circulating concentrations of SFAs varying by SFA chain length, as early as GWs 10-14, were significantly and differentially associated with subsequent risk of GDM. Our findings highlight the importance of assessing objectively measured, individual, and subclasses of SFAs to investigate their distinct biological and pathophysiologic roles in glucose homeostasis and cardiometabolic outcomes. This study was registered at www.clinicaltrials.gov as NCT00912132.

Liver Enzymes in Early to Mid-pregnancy, Insulin Resistance, and Gestational Diabetes Risk: A Longitudinal Analysis

Background: Liver enzymes may be implicated in glucose homeostasis; liver enzymes progressively change during pregnancy but longitudinal data during pregnancy in relation to insulin resistance and gestational diabetes (GDM) risk are lacking. We investigated longitudinal associations of γ-glutamyl transferase (GGT) and alanine aminotransferase (ALT) with insulin secretion and resistance markers across early to mid-pregnancy and subsequent GDM risk. Methods: Within the prospective Pregnancy Environment and Lifestyle Study cohort, 117 GDM cases were ascertained and matched to 232 non-GDM controls in a nested case-control study. Fasting blood samples were collected at two clinic visits (CV1, gestational weeks 10-13; CV2, gestational weeks 16-19). Linear mixed model and conditional logistic regression were used, adjusting for major risk factors for GDM. Results: In repeated measure analysis, after adjusting for confounders including body mass index and waist-to-hip ratio, GGT per standard deviation increment was associated with elevated fasting glucose and HOMA-IR (% change = 1.51%, 95% CI 0.56-2.46% and 7.43%, 95% CI 1.76-13.11%, respectively) and decreased adiponectin (% change = -2.86%, 95% CI-5.53 to -0.20%) from CV1 to CV2. At CV1 and CV2, GGT levels comparing the highest versus lowest quartile were associated with 3.01-fold (95% CI 1.32-6.85) and 3.51-fold (95% CI 1.37-8.97) increased risk of GDM, respectively. Progressively increased (<median at CV1, ≥median at CV2) and stably high (≥median at both CV1 and CV2) GGT levels were associated with 3.89- and 2.39-fold increased risk of GDM, compared to stably low levels (<median at both CV1 and CV2), respectively (both P < 0.05). Similar but non-significant trends were observed for ALT. Conclusion: Elevated levels of GGT in early and mid-pregnancy, even within the conventional normal range, and its progressive increase from early to mid-pregnancy may be implicated in the pathogenesis of GDM, highlighting its potential to inform early screening or preventive strategies to mitigate subsequent risk of GDM.

Early Pregnancy-Associated Plasma Protein A Concentrations Are Associated With Third Trimester Insulin Sensitivity

CONTEXT

First or early second trimester pregnancy-associated plasma protein A (PAPP-A) concentrations have previously been shown to be lower in women who subsequently develop gestational diabetes mellitus (GDM) and gestational hypertension.

OBJECTIVE

We therefore sought to investigate why circulating PAPP-A concentrations are related to the subsequent risk of GDM and gestational hypertension.

PATIENTS, DESIGN, AND SETTING

We measured serum PAPP-A concentrations around week 15 of pregnancy and related these to indices derived from week 28 oral glucose tolerance tests and blood pressures across pregnancy in the Cambridge Baby Growth Study cohort.

RESULTS

Increased PAPP-A concentrations were associated with reduced GDM risk [odds ratio 0.623 (0.453, 0.856), P = 3.5 × 10-3, n = 777] and reduced mean arterial blood pressures (β = -0.202 to -0.177, P = 1.7 to 6.9 × 10-3, n = 347 to 355). They were also negatively associated with week 28 fasting (β = -0.149, P = 6.6 × 10-4, n = 777) and 60-minute (β = -0.188, P = 1.5 × 10-5, n = 777) oral glucose tolerance test glucose concentrations. These associations were underpinned by the strong associations between increased week 15 PAPP-A concentrations and decreased week 28 insulin resistance (homeostasis model assessment of insulin resistance: β = -0.319, P = 1.7 × 10-13, n = 768), as well as increased insulin secretion relative to insulin sensitivity (insulin disposition index: β = 0.202, P = 6.5 × 10-6, n = 731).

CONCLUSIONS

These results suggest that links between PAPP-A concentrations in early pregnancy and subsequent glucose concentrations and blood pressures may be mediated by changes in insulin sensitivity (and secretion).

Pregnancy and acromegaly

INTRODUCTION

Acromegaly is a rare disorder in which, due to the high incidence of secondary hypogonadism, pregnancies are relatively rare. However, some women with acromegaly do get pregnant, which brings along questions about medication, complications and follow-up. This review tries to address these issues and provide the reader with practical information.

METHODS

This review summarizes published data.

CONCLUSIONS

Acromegaly is a disorder that is characterized by changes in growth hormone (GH), insulin-like growth factor-1 (IGF-1) and insulin concentrations and actions. All these hormones are important in pregnancy as well. In principle, the fetal-placental collaboration between mother and child more-or-less takes over the control over GH and IGF-1, not only in normal physiology but also to a certain extend in acromegaly. When medication for the high GH levels or actions is continued during pregnancy, both dopamine agonists, somatostatin analogs and GH receptor antagonists have been used and the available data suggest that there are no adverse consequences on mother or fetus to date. However, it is strongly advised to stop any medical intervention during pregnancy until more data are available on the safety of these compounds. Also, medical treatment is not needed as tumor size and disease activity are not reported to escape.

Potential Mechanisms underlying the Protective Effect of Pregnancy against Breast Cancer: A Focus on the IGF Pathway

A first full-term birth at an early age protects women against breast cancer by reducing lifetime risk by up to 50%. The underlying mechanism resulting in this protective effect remains unclear, but many avenues have been investigated, including lobular differentiation, cell fate, and stromal composition. A single pregnancy at an early age protects women for 30-40 years, and this long-term protection is likely regulated by a relatively stable yet still modifiable method, such as epigenetic reprograming. Long-lasting epigenetic modifications have been shown to be induced by pregnancy and to target the IGF pathway. Understanding how an early first full-term pregnancy protects against breast cancer and the role of epigenetic reprograming of the IGF system may aid in developing new preventative strategies for young healthy women in the future.