Insulin and carbohydrate metabolism

Performance of whole-genome promoter nucleosome profiling of maternal plasma cell-free DNA for prenatal noninvasive prediction of fetal macrosomia: a retrospective nested case-control study in mainland China

Background

Fetal macrosomia is common occurrence in pregnancy, which is associated with several adverse prognosis both of maternal and neonatal. While, the accuracy of prediction of fetal macrosomia is poor. The aim of this study was to develop a reliable noninvasive prediction classifier of fetal macrosomia.

Methods

A total of 3600 samples of routine noninvasive prenatal testing (NIPT) data at 12^+ 0–27^+ 6 weeks of gestation, which were subjected to low-coverage whole-genome sequencing of maternal plasma cell-free DNA (cfDNA), were collected from three independent hospitals. We identified set of genes with significant differential coverages by comparing the promoter profiling between macrosomia cases and controls. We selected genes to develop classifier for noninvasive predicting, by using support vector machine (SVM) and logistic regression models, respectively. The performance of each classifier was evaluated by area under the curve (AUC) analysis.

Results

According to the available follow-up results, 162 fetal macrosomia pregnancies and 648 matched controls were included. A total of 1086 genes with significantly differential promoter profiling were found between pregnancies with macrosomia and controls (p < 0.05). With the AUC as a reference，the classifier based on SVM (C_MA-A2) had the best performance, with an AUC of 0.8256 (95% CI: 0.7927–0.8586).

Conclusions

Our study provides that assessing the risk of fetal macrosomia by whole-genome promoter nucleosome profiling of maternal plasma cfDNA based on low-coverage next-generation sequencing is feasible.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-05027-w.

Feasibility and Safety of Continuous Glucose Monitoring in Infants at Risk of Hypoglycemia in a Rooming-in Setting

Background:Screening of neonatal hypoglycemia uses currently intermittent blood sampling. Continuous glucose monitoring (CGM) allows for tighter glucose control and better comfort for newborns and parents. CGM has previously been used in intensive care setting or blinded to clinicians. Our pilot study uses CGM in real time in rooming-in setting. Methods: CGM was attached within first two hours of life. Low glucose readings were verified to prevent overtreatment. Pairs of sensor readings and corresponding blood glucose measurements were assessed retrospectively. Neurodevelopmental evaluation was performed at 24 months. Results: 44 infants were enrolled. Three had verified hypoglycemia found due to CGM. No patient was below 2 standard deviations in any components of Bayley scales. Median scores were: Cognitive 100, language 86, motor 94. Conclusion: Use of CGM in a rooming-in environment is safe from clinical and neurodevelopmental point of view. Randomized trials are needed to evaluate superiority in longer term outcomes.

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.

The associations of nitrated polycyclic aromatic hydrocarbon exposures with plasma glucose and amino acids

Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) have been widely studied for their mutagenic and carcinogenic effects. This study aims to investigate whether exposure to nitro-PAHs is associated with biomarkers of carbohydrate metabolism, an underlying risk factor for metabolic disorder. Early morning urine and blood samples were longitudinally collected two times with a four-week interval from 43 healthy adults. Five urinary amino-PAHs (1-aminonaphthalene, 2-aminonaphthalene, 9-aminophenanthrene, 2-aminofluorene, and 1-aminopyrene) were measured as biomarkers of nitro-PAH exposures. We measured plasma concentrations of glucose and six amino acids that can regulate insulin secretion, including aspartate (Asp), glutamate (Glu), glutamine (Gln), alanine (Ala), Arginine (Arg), and ornithine (Orn). We found that increasing concentrations of 9-aminophenanthrene were significantly associated with increasing glucose levels and with decreasing Asp, Glu, Ala, and Orn levels. We estimated that 26.4 %-43.8 % of the 9-aminophenanthrene-associated increase in glucose level was mediated by Asp, Glu, and Orn. These results suggest that exposure to certain nitro-PAHs affects glucose homeostasis, partly resulting from the depletion of insulin-stimulating amino acids (Asp, Glu, and Orn).

Decreased KATP Channel Activity Contributes to the Low Glucose Threshold for Insulin Secretion of Rat Neonatal Islets

Transitional hypoglycemia in normal newborns occurs in the first 3 days of life and has clinical features consistent with hyperinsulinism. We found a lower threshold for glucose-stimulated insulin secretion from freshly isolated embryonic day (E) 22 rat islets, which persisted into the first postnatal days. The threshold reached the adult level by postnatal day (P) 14. Culturing P14 islets also decreased the glucose threshold. Freshly isolated P1 rat islets had a lower threshold for insulin secretion in response to 2-aminobicyclo-(2, 2, 1)-heptane-2-carboxylic acid, a nonmetabolizable leucine analog, and diminished insulin release in response to tolbutamide, an inhibitor of β-cell KATP channels. These findings suggested that decreased KATP channel function could be responsible for the lower glucose threshold for insulin secretion. Single-cell transcriptomic analysis did not reveal a lower expression of KATP subunit genes in E22 compared with P14 β cells. The investigation of electrophysiological characteristics of dispersed β cells showed that early neonatal and cultured cells had fewer functional KATP channels per unit membrane area. Our findings suggest that decreased surface density of KATP channels may contribute to the observed differences in glucose threshold for insulin release.

Chemical composition, antioxidant, and anti-diabetic activities of ethyl acetate fraction of Stachys riederi var. japonica (Miq.) in streptozotocin-induced type 2 diabetic mice

This work analysed the chemical composition, antioxidant, and enzyme inhibitory activities of solvent extract (SJ-ME) and fractions (SJ-HF, SJ-EAF, and SJ-MF) of the Stachys riederi var. japonica (Miq.) (SJ). Furthermore, the effect of SJ-EAF in STZ induced type 2 diabetic mice was examined. Among the samples, SJ-EAF exhibited a lower IC50 concentration of 64.2 ± 0.48 μg/mL for DPPH and 82.6 ± 0.09 μg/mL for ABTS+. The SJ-EAF concentration of 2.89 ± 0.03 μg and 2.27 ± 0.98 μg was equivalent to 1 μg of acarbose mediated enzyme inhibitory effect against α-amylase and α -glucosidase, respectively. The SJ-EAF did not show cytotoxicity (<80%) to NIH3T3 nor HepG2 cells but enhanced the glucose uptake in the IR-HepG2. LC-MS/MS of SJ-EAF showed the presence of a total of 16 compounds. Among the identified compounds, rosmarinic acid, caffeic acid, oleanolic acid, and ursolic acid showed high catalytic activity of α-amylase and α-glucosidase. The treatments of SJ-EAF restored the level of blood glucose, body weight, insulin, HDL and mRNA level of IRS1, GLUT2, GLUT4 and Akt whereas it reduced the excess elevation of total cholesterol, total triglycerides, LDL, AST, ALT, ALP, BUN, and creatinine in STZ induced diabetic mice. Overall, the present study concluded that the SJ-EAF exhibited promising antidiabetic activity.

Decreased placental apoptosis and autophagy in pregnancies complicated by gestational diabetes with large-for-gestational age fetuses

INTRODUCTION

Dysregulation of placental apoptosis and autophagy are observed in pregnancy complications including preeclampsia and fetal growth restriction. However, studies of their changes in the placentas of women with gestational diabetes mellitus (GDM) show inconsistent results. We aimed to compare the changes in apoptosis, autophagy, and Bcl-2 family proteins in the placentas from women with normal pregnancies and those with GDM, with or without large-for-gestational age (LGA) infants and to investigate the effect of hyperglycemia on the changes in apoptosis, autophagy, and Bcl-2 family proteins in primary cytotrophoblastic cells.

METHODS

Villous tissues were obtained from normal pregnant women and those with GDM, with or without LGA infants. Primary cytotrophoblast cells were isolated from normal term placentas and cultured under standard, hyperglycemic, or hyperosmotic conditions.

RESULTS

Compared to placentas from normal pregnant women, those from GDM women with LGA infants were heavier, had lower beclin-1 and DRAM levels, less M30 and cleaved PARP immunoreactivity, and increased Ki-67 immunoreactivity. These changes were associated with increased Bcl-xL and decreased Bak levels. Increased glucose concentration led to lower ATG5, beclin-1, LC3B-II, p62, and DRAM levels, lower annexin V and M30-positive cell percentages, and less cleaved PARP changes compared with standard culture conditions. Hyperglycemia caused higher Bcl-xL levels and lower Bak and Bad levels than did standard culture conditions.

DISCUSSION

There were differential changes in apoptosis and autophagy between placentas from normal pregnant women and those from GDM women with LGA infants. Bcl-2 family proteins are likely involved in the regulation of these changes.

Targeting glucose control in preterm infants: pilot studies of continuous glucose monitoring

OBJECTIVE

Hyperglycaemia is common in very preterm infants and is associated with adverse outcomes. Preventing hyperglycaemia without increasing the risk of hypoglycaemia is difficult. Real time tracking with continuous glucose monitors (CGM) may improve glucose control. We assessed the feasibility and safety of CGM to target glucose control in preterm infants, to inform a randomised controlled trial (RCT).

DESIGN

We performed a single centre study in very preterm infants during the first week of life. Accuracy was assessed by comparison of CGM with blood glucose levels (n=20 infants). In a separate pilot study of efficacy (n=20), real-time CGM combined with a paper guideline to target glucose control (2.6-10 mmol/L) was compared with standard neonatal care (masked CGM). Questionnaires were used to assess staff acceptability.

RESULTS

No concerns were raised about infection or skin integrity at sensor site. The sensor performed well compared with point-of-care blood glucose measurements, mean bias of -0.27 (95% CI -0.35 to -0.19). Per cent time in target range (sensor glucose 2.6-10 mmol/L) was greater with CGM than POC (77% vs 59%, respectively) and per cent time sensor glucose >10 mmol/L was less with CGM than POC (24% vs 40%, respectively). The CGM also detected clinically unsuspected episodes of hypoglycaemia. Staff reported that the use of the CGM positively improved clinical care.

CONCLUSIONS

This study suggests that CGM has sufficient accuracy and utility in preterm infants to warrant formal testing in a RCT.

Types of Carbohydrates Intake during Pregnancy and Frequency of a Small for Gestational Age Newborn: A Case-Control Study

The objective of this study was to assess the relationship between consumption of different types of carbohydrates (CHO) during pregnancy and the risk of having a small for gestational age (SGA) newborn. A retrospective matched case–control design was carried out with a total of 518 mother-offspring pairs. A total of 137 validated items were included in the food frequency questionnaire (FFQ). Conditional logistic regression models were used to calculate crude odds ratios (cORs) and adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Having more than 75 g/day of brown bread showed an inverse association with SGA (aOR = 0.64, CI 0.43–0.96). In contrast, an intake of industrial sweets more than once a day (aOR = 2.70, CI 1.42–5.13), or even 2–6 times a week (aOR = 1.84, CI 1.20–2.82), increased the odds of having a SGA newborn. During pregnancy, the higher the increase of wholegrain cereal and bread, the lower the possibility of having a SGA newborn, but the opposite occurred with refined sugar products—just consuming industrial bakery products or pastries twice a week increased the odds of having an SGA infant. Case–control studies cannot verify causality and only show associations, which may reflect residual confusion due to the presence of unknown factors. It is possible that a high consumption of sugary foods is a marker of a generally poor lifestyle.

Predictors of severe postoperative hyperglycemia after cardiac surgery in infants: a single-center, retrospective, observational study

PURPOSE

Hyperglycemia is a common issue in infants after cardiac surgery for congenital heart disease. Poor glycemic control is suspected to be associated with adverse postoperative outcomes. This study was performed to investigate clinical factors contributing to hyperglycemia in the perioperative period in infats.

METHODS

A total of 69 infants (aged 1-12 months) who were admitted to Yokohama City University Hospital Intensive Care Unit (ICU) after surgical repair of congenital heart diseases with cardiopulmonary bypass (CPB) were retrospectively analysed. Hyperglycemia was defined as blood glucose ≥ 250 mg/dL on ICU admission. Clinical background, operative factors, and postoperative factors were compared between the hyperglycemic and non-hyperglycemic groups. Additionally, multivariate analysis was performed to identify factors contributing to hyperglycemia.

RESULTS

Nineteen (27.5%) and 50 (72.5%) infants were classified into the hyperglycemic and non-hyperglycemic groups, respectively. Hyperglycemic infants were significantly younger, shorter, and weighed less, with a higher rate of chromosomal abnormalities. Intraoperatively, they also experienced longer CPB and surgery times and had higher peak lactate levels and higher inotropic requirements. Hyperglycemia was related to longer mechanical ventilation and longer ICU stays. Multivariate analysis detected intraoperative hyperglycemia, longer CPB time, younger age and chromosomal abnormality as significant factors.

CONCLUSION

Adding to hyperglycemia during the operation, longer CPB time younger age and chromosomal abnormality were identified as predictors of high blood glucose levels at ICU admission.

Insulin resistance, glucagon-like peptide-1 and factors influencing glucose homeostasis in neonates

OBJECTIVES

To explore the relationships between postmenstrual age (PMA), insulin, C-peptide, glucagon and blood glucose concentrations (BGCs) in preterm and term neonates. To compare glucagon-like peptide-1 (GLP-1) concentrations in fed versus never-fed neonates.

DESIGN

Observational.

SETTING

Dunedin Hospital Neonatal Intensive Care Unit, New Zealand.

PATIENTS

Term or preterm euglycaemic neonates (102) receiving routine blood tests (343 samples).

INTERVENTIONS

None: plasma was obtained from surplus samples from routine clinical care.

MAIN OUTCOME MEASURES

Insulin, C-peptide, GLP-1 and glucagon concentrations were measured in temporal association with BGC.

RESULTS

Insulin and C-peptide concentrations were elevated in very preterm infants (PMA≤32 weeks) and decreased to term; this relationship persisted when BGCs were accounted for. Generalised linear mixed models showed that insulin:C-peptide ratio and insulin:BGC ratio decreased significantly with increasing PMA (p<0.001). GLP-1 increased following initial oral feeds regardless of PMA (p<0.001).

CONCLUSION

Preterm neonates exhibit insulin resistance in the absence of hyperglycaemia. Enteral feeds result in an increase in GLP-1. These factors are likely to contribute to the increased risk of hyperglycaemia in premature neonates (PMA<32 weeks).

Maternal Midpregnancy Glucose Levels and Risk of Congenital Heart Disease in Offspring

IMPORTANCE

There is a well-described association between maternal diabetes mellitus and risk of congenital heart disease (CHD) in offspring. Although the clinical diagnoses of type 2 diabetes or gestational diabetes are strong risk factors for CHD, subclinical abnormalities of glucose and insulin metabolism are common within the general population and could also confer risk for CHD. We hypothesize that continuous measures of blood analytes related to maternal diabetes are related to odds of cardiac malformations.

OBJECTIVE

To explore the potential association of 2 different CHD phenotypes in offspring with maternal midpregnancy measures of glucose and insulin.

DESIGN, SETTING, AND PARTICIPANTS

Case-control study from a population-based cohort of 277 pregnant women in southern and central California carrying infants with tetralogy of Fallot (TOF) (n = 55), dextrotransposition of the great arteries (dTGA) (n = 42), or healthy infants without CHD (n = 180). Serum samples were collected from 2003 through 2007. The analysis was conducted from March through June 2015.

MAIN OUTCOMES AND MEASURES

Blood analytes related to maternal glucose metabolism were measured from random nonfasting second-trimester blood samples. We measured serum insulin levels by a validated radioimmunoassay, and we measured glucose levels. Multivariable logistic regression models estimated the association between these levels and case status.

RESULTS

Serum glucose values were elevated in the maternal samples for offspring with TOF (median, 97.0 mg/dL [to convert to millimoles per liter, multiply by 0.0555]) relative to controls (median, 91.5 mg/dL) (P = .01, Wilcoxon rank sum test), a phenomenon not observed in the maternal samples for offspring with dTGA (median, 90.0 mg/dL) relative to controls (P = .18, Wilcoxon rank sum test). Serum insulin levels were significantly different between controls (median, 18.8 μIU/mL [to convert to picomoles per liter, multiply by 6.945]) and maternal samples for offspring with dTGA (median, 13.1 μIU/mL; P = .048, Wilcoxon rank sum test) but not with TOF (median, 14.3 μIU/mL; P = .35, Wilcoxon rank sum test). Relative to maternal blood glucose levels of infants without cardiac malformations, we observed that maternal blood glucose levels in models including insulin were strongly associated with odds of TOF (adjusted odds ratio = 7.54; 95% CI, 2.30-24.69) but not with dTGA (adjusted odds ratio = 1.16; 95% CI, 0.28-4.79).

CONCLUSIONS AND RELEVANCE

These results represent a direct correlation of glucose as a continuous variable to odds of specific cardiac malformations. The association between serum glucose and odds of TOF indicates the need for additional epidemiological and mechanistic investigations into the risk conferred by insulin signaling and glucose metabolism during early pregnancy.

Clinically stable very low birthweight infants are at risk for recurrent tissue glucose fluctuations even after fully established enteral nutrition

OBJECTIVE

In previous cases, we have observed occasional hypoglycaemic episodes in preterm infants after initial intensive care. In this prospective study, we determined the frequency and severity of abnormal tissue glucose (TG) in clinically stable preterm infants on full enteral nutrition.

METHODS

Preterm infants born at <1000 g (n=23; G1) and birth weight 1000-1500 g (n=18; G2) were studied at a postmenstrual age of 32±2 weeks (G1) and 33±2 weeks (G2). Infants were fed two or three hourly, according to a standard bolus-nutrition protocol, and continuous subcutaneous glucose measurements were performed for 72 h. Normal glucose values were assumed at ≥2.5 mmol/L (45 mg/dL) and ≤8.3 mmol/L (150 mg/dL). Frequency, severity and duration of glucose values beyond normal values were determined.

RESULTS

We observed asymptomatic low TG values in 39% of infants in G1 and in 44% in G2. High TG values were detected in 83% in G1 and 61% in G2. Infants in G1 experienced prolonged and more severe low TG episodes, and also more frequent and severe high TG episodes. In G1 and G2, 87% and 67% of the infants, respectively, showed glucose fluctuations characterised by rapid glucose increase followed by a rapid glucose drop after feeds. In more mature infants, glucose fluctuations were less pronounced and less dependent on enteral feeds.

CONCLUSIONS

Clinically stable well-developing preterm infants beyond their initial period of intensive care show interstitial glucose instabilities exceeding values as low as 2.5 mmol/L and as high as 8.3 mmol/L. This novel observation may play an important role for the susceptibility of these high-risk infants for the development of the metabolic syndrome.

TRIAL REGISTRATION NUMBER

German trial registration number DRKS00004590.

Shape information in repeated glucose curves during pregnancy provided significant physiological information for neonatal outcomes

Objective

To use multilevel functional principal component analysis to exploit the information inherent in the shape of longitudinally sampled glucose curves during pregnancy, and to analyse the impact of glucose curve characteristics on neonatal birth weight, percentage fat and cord blood C-peptide.

Study Design and Setting

A cohort study of healthy, pregnant women (n = 884). They underwent two oral glucose tolerance tests (gestational weeks 14–16 and 30–32), which gave two glucose curves per woman.

Results

Glucose values were higher, and peaked later in third trimester than in early pregnancy. The curve characteristic “general glucose level” accounted for 91% of the variation across visits, and 72% within visits. The curve characteristics “timing of postprandial peak”, and “oscillating glucose levels” accounted for a larger part of the variation within visits (15% and 8%), than across visits (7% and <2%). A late postprandial peak during pregnancy, and high general glucose levels in third trimester had significant, positive effects on birth weight (p<0.05). Generally high glucose levels during pregnancy had a significant, positive impact on neonatal percentage fat (p = 0.04). High general glucose level in third trimester had a significant, positive impact on cord blood C-peptide (p = 0.004).

Conclusion

Shape information in entire OGTT curves provides significant physiological information of importance for several outcomes, and may contribute to the understanding of the metabolic changes during pregnancy.

Insulin dysregulation

Abnormalities of insulin metabolism include hyperinsulinaemia and insulin resistance, and these problems are collectively referred to as insulin dysregulation in this review. Insulin dysregulation is a key component of equine metabolic syndrome: a collection of endocrine and metabolic abnormalities associated with the development of laminitis in horses, ponies and donkeys. Insulin dysregulation can also accompany prematurity and systemic illness in foals. Causes of insulin resistance are discussed, including pathological conditions of obesity, systemic inflammation and pituitary pars intermedia dysfunction, as well as the physiological responses to stress and pregnancy. Most of the discussion of insulin dysregulation to date has focused on insulin resistance, but there is increasing interest in hyperinsulinaemia itself and insulin responses to feeding. An oral sugar test or in-feed oral glucose tolerance test can be performed to assess insulin responses to dietary carbohydrates, and these tests are now recommended for use in clinical practice. Incretin hormones are likely to play an important role in postprandial hyperinsulinaemia and are the subject of current research. Insulin resistance exacerbates hyperinsulinaemia, and insulin sensitivity can be measured by performing a combined glucose-insulin test or i.v. insulin tolerance test. In both of these tests, exogenous insulin is administered and the rate of glucose uptake into tissues measured. Diagnosis and management of hyperinsulinaemia is recommended to reduce the risk of laminitis. The term insulin dysregulation is introduced here to refer collectively to excessive insulin responses to sugars, fasting hyperinsulinaemia and insulin resistance, which are all components of equine metabolic syndrome.

Frequency and risk factors of fetal malnutrition among liveborn singleton term neonates using a computerised perinatal database, 2000-2006

AIM

The aim of this study was to determine the frequency, risk factors and anthropometric measurements of fetally malnourished, liveborn singleton term neonates.

METHODS

The computed delivery room data of 11.741 liveborn singleton term neonates was used to compare malnourished and nourished newborns.

RESULTS

Of the total subjects, 577 (4.9%) were malnourished. There were no differences between the groups with regard to gender distribution, Apgar scores, maternal parity, smoking during pregnancy and type of delivery. Maternal age and neonatal gestational age (GA) were significantly lower in malnourished newborns (P < 0.001). Birthweight (BW), birth length (BL) and head circumference (HC) were significantly lower in the malnourished group compared with well-nourished group (P < 0.001). Mean BW (g) was 2724.7 ± 17.0 in the malnourished group versus 3234.3 ± 3.8 in the well-nourished group; BL (cm) was 47.8 ± 0.1 in malnourished versus 49.5 ± 0.0 in well-nourished neonates; HC (cm) was 33.25 ± 0.1 in the malnourished versus 34.3 ± 0.0 in the well-nourished group. Between the groups, there were significant differences in the ratio of small, appropriate and large for GA (P < 0.001). Of the malnourished newborns, 35.5% were small for GA, 63.3% were appropriate for GA and 1.2% were large for GA.

CONCLUSION

Fetal malnutrition (FM) still exists despite the advances in current obstetric care. Neonates of adolescent mothers and of low GA are particularly at risk for FM. The BW, BL and HC of fetally malnourished neonates are lower than that of well-nourished neonates. Like term singleton appropriate and small for GA neonates, term singleton large for GA neonates could also have been fetally malnourished.

Fetal exposure to altered amniotic fluid glucose, insulin, and insulin-like growth factor-binding protein 1 occurs before screening for gestational diabetes mellitus

OBJECTIVE

We explored the possibility that perturbations in amniotic fluid glucose, insulin, and insulin-like growth factor-binding protein 1(IGFBP1) and/or metabolic acids exist before routine screening for GDM.

RESEARCH DESIGN AND METHODS

We selected consenting mother-infant pairs (n = 408) who met our inclusion criteria (singleton pregnancy, no genetic abnormalities, and no preexisting diabetes) and for whom sufficient amniotic fluid and appropriate medical information were available. We compared birth outcomes and second trimester amniotic fluid glucose, insulin, IGFBP1 concentrations, and amniotic fluid lactic, β-hydroxybutyric, and uric acids of mothers with gestational diabetes mellitus (GDM) (n = 52) with those of mothers with no diagnosis of GDM at >24 weeks (n = 356).

RESULTS

Higher amniotic fluid glucose, lactic acid, uric acid, and insulin and lower IGFBP1 concentrations were present by 15.1 ± 0.1 weeks in mothers in whom GDM was subsequently diagnosed. However, logistic regression showed that second trimester amniotic fluid glucose, but not insulin, IGFBP1, or metabolic acids was associated with an increased odds ratio (1.2 [95% CI 1.052-1.338]) for diagnosis of GDM at 24-28 weeks. In addition, probability contour maps that accounted for nonlinear relationships among the dynamically changing amniotic fluid constituents showed an increased risk for GDM with elevated second trimester amniotic fluid glucose in combination with either elevated amniotic fluid insulin or low amniotic fluid IGFBP1

CONCLUSIONS

Fetuses are exposed to increased amniotic fluid glucose before 15 weeks of gestation, suggesting that metabolic perturbations are underway before diagnosis and that earlier screening and intervention may be warranted.

Former small for gestational age (SGA) status is associated to changes of insulin resistance in obese children during weight loss

OBJECTIVE

Former small for gestational age (SGA) children are at risk of both obesity and insulin resistance. Longitudinal studies are required to assess a possible relationship between former SGA status and insulin resistance independent of weight status. We hypothesized that obese children with former appropriate for gestational age (AGA) status improve their insulin resistance during weight loss more effectively compared to obese children with former SGA status.

METHODS

A 1-yr longitudinal follow-up study design was adopted in the primary care setting and 341 obese children [8% SGA, mean age 10.5 +/- 0.1 yr, body mass index (BMI) 27.7 +/- 0.2, BMI-standard deviation score (SDS) 2.47 +/- 0.02] were taken for the study. Outpatient 1-yr intervention was based on exercise, behavior and nutrition therapy. We measured insulin resistance index following the Homeostasis model assessment model (HOMA), blood pressure, lipids, glucose, and insulin in all children before and after the 1-yr intervention.

RESULTS

In a multiple linear regression analysis adjusted for age, gender, and pubertal stage, changes of HOMA were significantly related to changes of BMI-SDS (-2.55 per loss of 1 BMI-SDS unit; p < 0.001) and SGA status (+2.05 for SGA children; p < 0.001). Changes of BMI-SDS together with gender and age explained 10% of the variance of changes of HOMA, while SGA status explained an additional 4%. After adjustment for age, sex, pubertal stage, and BMI-SDS, former SGA status was not significantly related to any other considered cardiovascular risk factor.

CONCLUSIONS

Change of weight status predicted change of HOMA in obese children participating in a lifestyle intervention. Changes of HOMA were also predicted by former SGA status supporting that former SGA status influences insulin resistance.

The human insulin superfamily of polypeptide hormones

The identification in the 1950s of insulin, an essential carbohydrate regulatory hormone, as consisting of not one but two peptide chains linked by three disulfide bonds in a distinctive pattern was a milestone in peptide chemistry. When it was later found that relaxin also possessed a similar overall structure, the term 'insulin superfamily' was coined. Use of methods of conventional protein chemistry followed by recombinant DNA and more recently bioinformatics has led to the recognition that insulin is the precursor to a large protein superfamily that extends beyond the human. Insulin-like peptides are found not only in vertebrates such as mammals, birds, reptiles, amphibians but also in the invertebrates such as chordates, molluscs and insects. All superfamily members share the distinctive insulin structural motif. In the human, there exists ten members of the superfamily, each of which are expressed on the ribosome as a single-chain pre-prohormone that undergoes proteolytic processing to produce eight double-chain mature proteins and two single-chain forms. The six cysteine residues that form the three insulin disulfide cross-links - one intramolecular within the A-chain and two intermolecular between that A- and B-chains - are absolutely conserved across all members of the superfamily. They are responsible for imparting a similar overall tertiary structure. The human insulin superfamily members have each evolved to assume remarkably distinctive biological functions ranging from glucose homeostasis to neuroendocrine actions. That such diversity is contained within a modestly sized superfamily is testament to efficiency of the insulin structural motif as an evolutionary template.