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

Combined detection of serum adiponectin and pregnancy-associated plasma protein A for early prediction of gestational diabetes mellitus

Early diagnosis of gestational diabetes mellitus (GDM) reduces the risk of adverse perinatal and maternal outcomes. At present, the value of serum adiponectin (ADP) and pregnancy-associated plasma protein A (PAPP-A) in clinical practice for the diagnosis of GDM in early pregnancy is unclear. To investigate the predictive value of serum ADP and PAPP-A in GDM. The electronic medical record data of all pregnant women from Zhongshan People's Hospital from 2018 to 2021 were retrospectively collected and divided into GDM group and control group according to whether GDM occurred. ADP and PAPP-A levels of the 2 groups were detected in early pregnancy, and the related factors of GDM were analyzed by binary logistic regression analysis. Receiver operating characteristic (ROC) curves of ADP and PAPP-A in predicting GDM in the early pregnancy were plotted and their clinical predictive value was analyzed. The significance level for all statistical tests is 0.05. Compared with the non-GDM group, the ADP of the GDM group was significantly lower than that of the non-GDM group [(8.19 ± 2.24) vs. (10.04 ± 2.73)]mg/L, the difference between groups was statistically significant (P < .05), and the multiple of median (MoM) of PAPP-A was significantly lower than that of the non-GDM group (1.13 ± 0.52) versus (1.45 ± 0.61) (P < .05). Binary logistic regression analysis showed that elevated serum ADP and PAPP-A levels were negatively correlated with the subsequent development of GDM [odds ratio (OR) 95% confidence interval (95% CI)] was 0.626 (0.536, 0.816), 0.934 (0.908, 0.961), respectively, P < .05.ROC curve analysis showed that the sensitivity and specificity of ADP and PAPP-A in predicting gestational diabetes were79.1% and 58.6%, respectively, 92.7% and 73.1%, and respectively. The area under curve (AUC) is 0.755 for ADP and 0.770 for PAPP-A. The AUC of the combined detection was 0.867, both of which were higher than that of single index diagnosis, and the sensitivity and specificity of the combined detection were 0.958 and 0.853, respectively. In summary, PAPP-A and ADP levels are independent related factors affecting the occurrence of GDM. The combined detection of PAPP-A and ADP should be utilized in diagnosing GDM to improve pregnancy outcomes for pregnant women.

Early prediction of gestational diabetes mellitus using first trimester maternal serum pregnancy-associated plasma protein-a: A cross-sectional study

Background and Aims

The oral glucose tolerance test with 75 g glucose is commonly regarded as the gold standard (GS) for the detection of gestational diabetes mellitus (GDM). However, one limitation of this test is its administration in the late second trimester of pregnancy in some countries (e.g., Iran). This study aimed to evaluate the accuracy of pregnancy-associated plasma protein-A (PAPP-A) for predicting GDM in the early first trimester of pregnancy using a novel statistical modeling technique.

Methods

The study population consisted of 344 pregnant women who participated in the first trimester screening program for GDM. Maternal serum PAPP-A levels were measured between 11 and 13 gestational weeks for all participants. A Bayesian latent profile model (LPM) under the skew-t (ST) distribution was employed to estimate the diagnostic accuracy measures of PAPP-A in the absence of GS test outcomes.

Results

The mean (standard deviation) age of the participants was 28.87 ± 5.20 years. The median (interquartile range (IQR)) PAPP-A MoM was 0.91 (0.69-1.34). Utilizing the LPM under the ST distribution while adjusting for covariates, the sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of PAPP-A were 92% (95% credible interval [CrI]: 0.89, 0.98), 81% (95% CrI: 0.76, 0.91), and 0.91 (95% CrI: 0.83, 0.97), respectively. Notably, the pregnant women with GDM had significantly lower PAPP-A values (β = -0.52, 95% CrI [-0.61, -0.46]).

Conclusion

Generally, our findings confirmed that PAPP-A could serve as a potential screening tool for the identification of GDM in the early stages of pregnancy.

Vitronectin promotes insulin resistance in trophoblast cells by activating JNK in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a common disorder in the clinic, which may lead to severe detrimental outcomes both for mothers and infants. However, the underlying mechanisms for GDM are still not clear. In the present study, we performed label-free proteomics using placentas from GDM patients and normal controls. Vitronectin caused our attention among differentially expressed proteins due to its potential role in the pathological progression of GDM. Vitronectin was increased in the placentas of GDM patients, which was confirmed by Western blot analysis. Vitronectin represses insulin signal transduction in trophoblast cells, whereas the knockdown of vitronectin further potentiates insulin-evoked events. Neutralization of CD51/61 abolishes the repressed insulin signal transduction in vitronectin-treated trophoblast cells. Moreover, vitronectin activates JNK in a CD51/61-depedent manner. Inhibition of JNK rescues impaired insulin signal transduction induced by vitronectin. Overall, our data indicate that vitronectin binds CD51/61 in trophoblast cells to activate JNK, and thus induces insulin resistance. In this regard, increased expression of vitronectin is likely a risk factor for the pathological progression of GDM. Moreover, blockade of vitronectin production or its receptors (CD51/61) may have therapeutic potential for dealing with GDM.

Placental Growth Factor and Pregnancy-Associated Plasma Protein-A as Potential Early Predictors of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications and one of the main causes of adverse pregnancy outcomes. An early diagnosis of GDM is of fundamental importance in clinical practice. However, the major professional organizations recommend universal screening for GDM, using a 75 g oral glucose tolerance test at 24-28 weeks of gestation. A selective screening at an early stage of pregnancy is recommended only if there are maternal risk factors for diabetes. As a result, the GDM diagnosis is often delayed and established after the appearance of complications. The manifestation of GDM is directly related to insulin resistance, which is closely associated with endothelial dysfunction. The placenta, the placental peptides and hormones play a pivotal role in the manifestation and progression of insulin resistance during pregnancy. Recently, the placental growth factor (PlGF) and plasma-associated protein-A (PAPP-A), have been shown to significantly affect both insulin sensitivity and endothelial function. The principal function of PAPP-A appears to be the cleavage of circulating insulin-like growth factor binding protein-4 while PlGF has been shown to play a central role in the development and maturation of the placental vascular system and circulation. On one hand, these factors are widely used as early predictors (11-13 weeks of gestation) of complications during pregnancy, such as preeclampsia and fetal aneuploidies, in most countries. On the other hand, there is increasing evidence for their predictive role in the development of carbohydrate disorders, but some studies are rather controversial. Therefore, this review aims to summarize the available literature about the potential of serum levels of PlGF and PAPP-A as early predictors in the diagnosis of GDM.

Value of PAPP-A combined with BMI in predicting the prognosis of gestational diabetes mellitus: an observational study

The aim of this study was to investigate the potential of pregnancy-associated plasma protein A (PAPP-A) and clinical data in predicting gestational diabetes mellitus (GDM). Clinical data of 318 pregnant women with GDM and 200 healthy pregnant women were retrospectively analysed. The age, BMI and caesarean section in GDM were significantly higher than in normal group. Serum and placental levels of PAPP-A were significantly lower in GDM than in normal group. Pearson's correlation analysis showed that serum levels of PAPP-A were negatively correlated with BMI and blood glucose level. Binary logistic regression analysis displayed that PAPP-A were the potential factors influencing GDM. The area under the ROC curve (AUC) for PAPP-A combined with BMI in predicting GDM was 0.941, significantly higher than that of the single one. The potential of PAPP-A in the first trimester is limited in predicting GDM. PAPP-A combined with BMI is highly conductive for predicting GDM.Impact statementWhat is already known on this subject? GDM not only increases the risk of perinatal morbidity, but also results in an increased risk of long-term sequelae for both mother and child including diabetes, cardiovascular disease obesity. Previous data indicate that besides glycemic control in the second trimester, interventions initiated early in pregnancy can reduce the rate of GDM in pregnant women. The expression of PAPP-A in serum of GDM pregnant women was decreased in the first trimester. Whereas, whether PAPP-A can be as an early predictor of GDM is not clear.What do the results of this study add? The present study shows that PAPP-A MoM was less than 0.6757 in the first trimester of pregnancy is more prone to GDM. The potential of PAPP-A in the first trimester is limited in predicting GDM. PAPP-A combined with BMI is highly conductive for predicting GDM.What are the implications of these findings for clinical practice and/or further research? Early GDM prediction is crucial for prevention and management of GDM, to cope with the rising prevalence of GDM and reduce later life chronic disease of both mother and child. Based on the level of PAPP-A MoM and BMI, interventions such as lifestyle changes initiated early in pregnancy shouldbeenabledin pregnant women.

The Mystery of Exosomes in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the common pregnancy complications, which increases the risk of short-term and long-term adverse consequences in both the mother and offspring. However, the pathophysiological mechanism of GDM is still poorly understood. Inflammation, insulin resistance and oxidative stress are considered critical factors in the occurrence and development of GDM. Although the lifestyle intervention and insulin are the primary treatment, adverse pregnancy outcomes still cannot be ignored. Exosomes have a specific function of carrying biological information, which can transmit information to target cells and play an essential role in intercellular communication. Their possible roles in normal pregnancy and GDM have been widely concerned. The possibility of exosomal cargos as biomarkers of GDM is proposed. This paper reviews the literature in recent years and discusses the role of exosomes in GDM and their possible mechanisms to provide some reference for the prediction, prevention, and treatment of GDM and improve the outcome of pregnancy.

Extracellular vesicles and their role in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a complex disorder that is defined by glucose intolerance with onset during pregnancy. The incidence of GDM is increasing worldwide. Pregnancies complicated with GDM have higher rates of maternal and fetal morbidity with short- and long-term consequences, including increased rates of cardiovascular disease and type II diabetes for both the mother and offspring. The pathophysiology of GDM still remains unclear and there has been interest in the role of small extracellular vesicles (sEVs) in the maternal metabolic adaptations that occur in pregnancy and GDM. Small EVs are nanosized particles that contain bioactive content, including miRNAs and proteins, which are released by cells to provide cell-to-cell communication. Pregnancy induces an increase in total and placental-secreted sEVs across gestation, with a further increase in sEV number and changes in the protein and miRNA composition of these sEVs in GDM. Research has suggested that these sEVs have an impact on maternal adaptations during pregnancy, including targeting the pancreas, skeletal muscle and adipose tissue. Consequently, this review will focus on the differences in total and placental sEVs in GDM compared to normal pregnancy, the role of sEVs in the pathophysiology of GDM and their clinical application as potential GDM biomarkers.

PAPPA-mediated adipose tissue remodeling mitigates insulin resistance and protects against gestational diabetes in mice and humans

Pregnancy is a physiological state of continuous adaptation to changing maternal and fetal nutritional needs, including a reduction of maternal insulin sensitivity allowing for appropriately enhanced glucose availability to the fetus. However, excessive insulin resistance in conjunction with insufficient insulin secretion results in gestational diabetes mellitus (GDM), greatly increasing the risk for pregnancy complications and predisposing both mothers and offspring to future metabolic disease. Here, we report a signaling pathway connecting pregnancy-associated plasma protein A (PAPPA) with adipose tissue expansion in pregnancy. Adipose tissue plays a central role in the regulation of insulin sensitivity, and we show that, in both mice and humans, pregnancy caused remodeling of adipose tissue evidenced by altered adipocyte size, vascularization, and in vitro expansion capacity. PAPPA is known to be a metalloprotease secreted by human placenta that modulates insulin-like growth factor (IGF) bioavailability through prolteolysis of IGF binding proteins (IGFBPs) 2, 4, and 5. We demonstrate that recombinant PAPPA can stimulate ex vivo human adipose tissue expansion in an IGFBP-5- and IGF-1-dependent manner. Moreover, mice lacking PAPPA displayed impaired adipose tissue remodeling, pregnancy-induced insulin resistance, and hepatic steatosis, recapitulating multiple aspects of human GDM. In a cohort of 6361 pregnant women, concentrations of circulating PAPPA are inversely correlated with glycemia and odds of developing GDM. These data identify PAPPA and the IGF signaling pathway as necessary for the regulation of maternal adipose tissue physiology and systemic glucose homeostasis, with consequences for long-term metabolic risk and potential for therapeutic use.

Pregnancy-associated plasma proteins and Stanniocalcin-2 - Novel players controlling IGF-I physiology

IGF-I was originally discovered as a GH-dependent growth factor stimulating longitudinal growth. Currently, however, it has become evident that the biological activities of IGF-I extend well beyond those of a simple growth factor and impact such processes as insulin sensitivity, aging, cancer and cardiovascular disease. The vast majority of IGF-I is tightly bound to IGF-binding proteins (IGFBPs), which renders IGF-I unable to stimulate the IGF-I receptor (IGF-IR) in vivo. This binding means that liberation of IGF-I from the IGFBPs is an important step controlling IGF-I action. In this context, IGFBP-cleaving enzymes appear to play a key role. Enzymatic cleavage of the IGFBPs markedly lowers their ligand affinity, and as a consequence, IGF-I becomes liberated and hence available for stimulation of the IGF-IR. Two of the best-characterized IGFBP-cleaving enzymes are pregnancy-associated plasma protein-A (PAPP-A) and its paralog PAPP-A2. The two enzymes (often referred to as pappalysins) regulate the liberation of IGF-I in a highly controlled manner. PAPP-A is believed to act predominantly in tissues, serving to liberate IGF-I at the cell surface in close proximity to the IGF-IR. In keeping with this notion, mice lacking PAPP-A exhibit reduced body size, despite having normal circulating IGF-I concentrations. In contrast, human findings indicate that altered PAPP-A2 activity changes circulating IGF-I concentrations, although PAPP-A2 is also present in high concentrations in tissues. Thus, PAPP-A2 appears to impact circulating, as well as tissue, IGF-I activity. The enzymatic activity of PAPP-A and PAPP-A2 was recently discovered to be regulated by the protein Stanniocalcin-2 (STC2). By binding to the enzymatic sites of PAPP-A and PAPP-A2, STC2 inhibits their activity. To date, the majority of findings demonstrating the ability of pappalysins and STC2 to regulate IGF-I action are from preclinical studies. However, clinical studies are now beginning to emerge. In this review, we will summarize our data on STC2, PAPP-A and PAPP-A2 in humans. These results indicate that pappalysins and STC2 constitute an important IGF-I activity-regulating system that warrants further investigation.

Pregnancy associated plasma protein A: An indicator of adverse obstetric outcomes in a South India population

Objective

First trimester aneuploidy screening (FTAS) has become an integral part of antenatal care in most of centers in India. The serum markers used for FTAS are pregnancy-associated plasma protein A (PAPP-A) and beta human chorionic gonadotropin. In the present study, we aimed to assess the role of PAPP-A in specific adverse fetal maternal events. To analyze pregnancy outcomes with low maternal PAPP-A (≤5^th percentile) at the FTAS screening test in southern India, and them compared with a control group of >5^th percentile value.

Materials and Methods

A total of 1800 consecutive pregnancies in the first trimester were followed up with PAPP-A levels. The study group consisted 108 subjects, which was compared with a matched control group of 288 subjects. The outcomes considered were spontaneous abortions, fetal anomalies, preterm delivery (PTD), hypertension in pregnancy, intrauterine growth restriction, gestational diabetes, mode of delivery, and birthweight.

Results

For our grouped data, the 5^th percentile value for PAPP-A was 0.49 multiple of medians, (incidence-6%). The incidence of fetal major anomalies was higher in the study group [odds ratio (OR): 1.87]. The incidence of minor anomalies, gestational diabetes, and hypertensive disorders was higher in the study group but not statistically significant. The total rate of PTDs (OR:2.1), small-for-gestation-age fetuses (OR:2.3), and low birthweight babies (OR- 2.12) was significantly higher in the study group. We found positive likelihood ratio of 1.4 for PTD, 2 for <5^th percentile birthweight, and 1.7 for <10^th centile birthweight.

Conclusion

Low PAPP-A pregnancies are at risk of various obstetric complications. Hence, such a pregnancy should have closer surveillance. Further research work on intervention strategy is needed.

Temporal trends without seasonal effects on gestational diabetes incidence relate to reductions in indices of insulin secretion: the Cambridge Baby Growth Study

AIMS

The incidence of gestational diabetes has been reported to have risen over the first decade of this century. Some studies have also found it to vary with seasons of the year. We investigated temporal and seasonal trends on gestational diabetes incidence in a single-centre cohort study from Cambridge, UK, and attempted to explain trends using associated risk factors.

METHODS

Using a cosinor model, we tested both temporal and seasonal trends in gestational diabetes incidence in 1074 women recruited to the Cambridge Baby Growth Study in 2001-2009 who underwent oral glucose tolerance tests around week 28 of pregnancy.

RESULTS

There was a temporal increase in gestational diabetes incidence over the course of recruitment to this study [0.014 (0.005, 0.022) proportional increase per year, p = 2.1 × 10^-3], but no seasonal effect (p = 0.7). HOMA B [- 0.015 (- 0.025, - 0.005) per year, p = 3.0 × 10^-3] and the insulin disposition index [- 0.036 (- 0.060, - 0.013) per year, p = 3.0 × 10^-3], unlike HOMA S, showed negative temporal trends. Risk factor analyses showed a concomitant temporal slight increase in the index of multiple deprivation [0.191 (0.138, 0.257) units per year, p = 4.6 × 10^-10]. This index was positively associated with HOMA B (p = 6.1 × 10^-5) but not directly with gestational diabetes (p = 0.6), HOMA S (p = 0.2) or the insulin disposition index (p = 0.4).

CONCLUSIONS

In this cohort, there were temporal, but not seasonal, increases in gestational diabetes incidence between the years 2001 and 2009, which appeared to be related more to reductions in insulin secretion than sensitivity. Possible mediators of this link include confounding factors related to deprivation.

Use of pregnancy-associated plasma protein-A during oocyte in vitro maturation increases IGF-1 and affects the transcriptional profile of cumulus cells and embryos from Nelore cows

Insulin-like growth factor 1 (IGF-1) activity is established by the regulation of IGF binding protein activity, which blocks IGF-1 functions, whereas pregnancy-associated plasma protein-A (PAPP-A) improves IGF-1 bioavailability and facilitates binding to IGF receptors. To further extend our understanding of the effect of exogenous PAPP-A on bovine embryo production, we added this protein during in vitro maturation of cumulus-oocyte complexes (COCs); moreover, we assessed its effects on IGF-1 quantity in the maturation medium, embryonic yield and postwarming survival, blastocyst quality, and transcript abundance. Bovine COCs were matured in a serum-free medium, either with PAPP-A supplementation (100 ng/ml) or without (control). The treatment group produced higher IGF-1 concentrations in the maturation medium; however, showed no difference on cleavage, blastocysts rates, and embryonic survival 3 and 24 hr postcryopreservation. Regarding gene expression, VNN1 was upregulated, whereas AGPAT9, FASN, EGFR, HAS2, and IMPDH1 were downregulated in PAPP-A treated. PAPP-A treated, CPT2, DNMT3A, and TFAM were upregulated, whereas ATF4 and IFITM3 were downregulated. We concluded that although the addition of PAPP-A did not affect embryo yield and blastocyst survival, higher IGF-1 levels may affect embryo competence through differential expression of genes involved in lipid metabolism, oocyte competence, and mitochondrial function.

PAPP-A concentrations change in patients with gestational diabetes

Our aim was to assess the relationship between gestational diabetes and glucose intolerance regarding maternal serum PAPP-A and free β-hCG concentrations in first trimester pregnancies. This study was conducted on 278 women between 18-45 years old with singleton pregnancies. The subjects were divided into four groups, according to their 50 and 100 g OGTT results. Group 1 was the Control Group, Group 2 with positive 50 g OGTT results, but negative 100 g, Group 3 had gestational diabetes after testing with 50 g OGTT (≥180 mg/dl) or with 100 g OGTT. Finally Group 4 was made of women with a one single high glucose level after testing with 100 g OGTT. These groups were analysed in terms of OGTT results. In the GDM group, serum PAPP-A concentrations were significantly lower when compared with the Control Group's (p = 0.015). There was either no significant differences regarding free β-hCG concentrations among the groups. GDM rate is 21.1%, the patients with GDM had significantly low concentrations of serum PAPP-A but their f β-hCG concentrations did not change. Our results are supported by several studies. However, we need greater numbered studies for exact results.IMPACT STATEMENTWhat is already known on this subject? Pregnancy associated plasma protein A (PAPP-A) is produced by the placenta in pregnancy. PAPP-A cleaves insulin-like growth factor (IGF) binding proteins. It would appear to have a role in regulating IGF bioavailability in pregnancy. This is important as the IGF axis plays a critical role in fetal growth, and placental growth and function during pregnancy. Some studies have reported that PAPP-A levels were impaired among women who subsequently developed GDM.What do the results of this study add? The patients with GDM had significantly low concentrations of serum PAPP-A but their free β-hCG levels did not change.What are the implications of these findings for clinical practice and/or further research? By looking at PAPP-A concentrations, we can predict patients that will be gestational diabetic and take precautions to protect the babies health, such as their diet or exercise.

Age at Menarche and Blood Pressure in Pregnancy

Objectives

To investigate whether age at menarche is related to maternal blood pressure in pregnancy and, if so, whether obesity and insulin resistance can modify the associations.

Study Design

Analysis of data collected from 438 pregnant women from the longitudinal and prospective Cambridge Baby Growth Study.

Main Outcome

Testing associations between questionnaire-derived age at menarche and blood pressure measurements in pregnancy collected from hospital notes, and investigating whether any associations were altered by maternal pre-pregnancy body mass index (BMI) and insulin resistance.

Measures

Mean arterial blood pressure at four time points across pregnancy, age at menarche, (Homeostasis Model Assessment) insulin resistance around week 28 of pregnancy.

Results

For each increased year in age at menarche there was a drop in mean arterial blood pressure (mmHg) of 0.6 at 11.9 weeks, 0.9 at 31.4 and 37.0 weeks, and 0.4 at 38.8 weeks (a maximal difference of over 7 mmHg across extremes of AAM). Each association was attenuated by both maternal pre-pregnancy BMI and insulin resistance.

Conclusions

Age at menarche is negatively associated with future blood pressure in pregnancy, so those with the earliest age at menarche have the highest blood pressures. Either these associations may be mediated by links between age at menarche and obesity/insulin resistance, or there may be a confounder (e.g. systemic inflammation) that links age at menarche to each of them.

Associations of vomiting and antiemetic use in pregnancy with levels of circulating GDF15 early in the second trimester: A nested case-control study

Background: Although nausea and vomiting are very common in pregnancy, their pathogenesis is poorly understood. We tested the hypothesis that circulating growth and differentiation factor 15 (GDF15) concentrations in early pregnancy, whose gene is implicated in hyperemesis gravidarum, are associated with nausea and vomiting. Methods: Blood samples for the measurement of GDF15 and human chorionic gonadotrophin (hCG) concentrations were obtained early in the second trimester (median 15.1 (interquartile range 14.4-15.7) weeks) of pregnancy from 791 women from the Cambridge Baby Growth Study, a prospective pregnancy and birth cohort. During each trimester participants completed a questionnaire which included questions about nausea, vomiting and antiemetic use. Associations with pre-pregnancy body mass indexes (BMI) were validated in 231 pregnant NIPTeR Study participants. Results: Circulating GDF15 concentrations were higher in women reporting vomiting in the second trimester than in women reporting no pregnancy nausea or vomiting: 11,581 (10,977-12,219) (n=175) vs. 10,593 (10,066-11,147) (n=193) pg/mL, p=0.02). In women who took antiemetic drugs during pregnancy (n=11) the GDF15 levels were also raised 13,157 (10,558-16,394) pg/mL (p =0.04). Serum GFD15 concentrations were strongly positively correlated with hCG levels but were inversely correlated with maternal BMIs, a finding replicated in the NIPTeR Study. Conclusions: Week 15 serum GDF15 concentrations are positively associated with second trimester vomiting and maternal antiemetic use in pregnancy. Given GDF15's site of action in the chemoreceptor trigger zone of the brainstem and its genetic associations with hyperemesis gravidarum, these data support the concept that GDF15 may be playing a pathogenic role in pregnancy-associated vomiting.

The association between age at menarche and later risk of gestational diabetes is mediated by insulin resistance

AIMS

Associations have been reported between age at menarche and the later risk of gestational diabetes. However, it is not known whether these associations reflect differences in insulin sensitivity and/or pancreatic β-cell function in pregnancy.

METHODS

We examined this question in women enrolled in the prospective Cambridge Baby Growth Study who recalled their age at menarche in questionnaires during pregnancy. Polynomial logistic and linear regression models were used to relate menarche timing to the risk of gestational diabetes, both unadjusted and adjusted for the Homeostasis Model Assessments of insulin resistance (HOMA IR) and pancreatic β-cell function (HOMA B) at week 28 of pregnancy.

RESULTS

Age at menarche showed a U-shaped association with gestational diabetes risk (linear term: p = 9.5 × 10^-4; quadratic term: p = 1.0 × 10^-3; n = 889; overall model p = 8.1 × 10^-3). Age at menarche showed a negative linear association with insulin resistance (HOMA IR: β = -0.13, p = 5.2 × 10^-4, n = 771), which explained the relationship between age at menarche and gestational diabetes risk (adjusted linear term going from p = 0.03-0.08; adjusted quadratic term going from p = 0.04-0.08; n = 771). Age at menarche also showed a negative linear association with β-cell function (HOMA B: β = -0.11, p = 2.8 × 10^-3, n = 771) but this did not attenuate the relationship between age at menarche and gestational diabetes (adjusted linear term p = 0.02; adjusted quadratic term p = 0.03, n = 771).

CONCLUSIONS

These results suggest that the associations between age at menarche and risk of gestational diabetes and raised pregnancy glucose concentrations may be mediated by insulin resistance.

Insulin Treatment Cannot Promote Lipogenesis in Rat Fetal Lung in Gestational Diabetes Mellitus Because of Failure to Redress the Imbalance Among SREBP-1, SCAP, and INSIG-1

Gestational diabetes mellitus (GDM) has a higher incidence of neonatal respiratory distress syndrome, and lipogenesis is required for the synthesis of pulmonary surfactants. The aim of this study was to determine the effect of insulin treatment in GDM on the production of lipids in the lungs of fetal rats. GDM was induced by streptozotocin, and insulin was used to manage diabetes. Type II alveolar epithelial cells (AEC II), bronchoalveolar lavage fluid (BALF), and lung tissues of the neonatal rats were sampled for analyses. Insulin treatment could not decrease plasma glucose to normal level at a later gestational stage. Lipids/phospholipids in AEC II, BALF, and lung tissues decreased in GDM, and insulin treatment could not increase the levels; quantitative PCR and western blotting demonstrated a lower level of sterol regulator element-binding protein 1 (SREBP-1), SREBP cleavage-activating protein (SCAP), and insulin-induced gene 1 (INSIG-1) in GDM, but insulin treatment upregulated only SREBP-1. Nuclear translocation of the SREBP-1 protein in AEC II was impaired in GDM, which could not be ameliorated by insulin treatment. These findings indicated that insulin treatment in GDM cannot promote lipogenesis in the fetal lung because of failure to redress the imbalance among SREBP-1, SCAP, and INSIG-1.