Changes in insulin sensitivity and insulin secretion during pregnancy and post partum in women with gestational diabetes

How to take action beyond ambulatory glucose profile: Latin American expert recommendations on CGM data interpretation

PURPOSE

This expert consensus provides a standardized methodology for interpreting continuous glucose monitoring (CGM) data to optimize diabetes management. It aims to help healthcare professionals recognize glycemic patterns and apply targeted interventions based on real-time glucose metrics.

METHODS

A systematic literature review informed expert panel discussions. Specialists from Latin America assessed CGM interpretation challenges, reviewed key metrics, and reached consensus through an anonymous voting process. The recommendations align with international guidelines while addressing regional limitations in technology access and healthcare infrastructure.

RESULTS

Reliable CGM data interpretation requires at least 70% sensor use over 14 days. The Ambulatory Glucose Profile (AGP) report serves as the primary tool, offering essential metrics such as time in range (TIR), time below range (TBR), time above range (TAR), coefficient of variation (CV), and glucose management indicator (GMI). Identifying hyperglycemia, hypoglycemia, and glucose variability allows for personalized treatment adjustments. The panel adopted international glycemic targets, adapting them to Latin American settings. The time in tight range (TITR) was considered but not included due to limited supporting evidence and regional barriers to advanced CGM technology.

CONCLUSIONS

Standardized CGM interpretation improves glycemic control and treatment decisions. These recommendations provide a structured approach to diabetes care, aiming to enhance clinical outcomes and address healthcare disparities in Latin America.

Using an Oral Sugar Test to Biologically Validate the Use of a Commercial Enzyme Immunoassay to Measure Salivary Insulin in Western Lowland Gorillas (Gorilla gorilla gorilla)

Noninvasive evaluations of hormones can contribute to the assessment of health and welfare of animals. Variations in insulin levels and sensitivity, for example, have been linked to health concerns in non-human and human primates including insulin resistance, diabetes, and heart disease, the leading cause of death in zoo-housed gorillas. Few published studies have assessed insulin concentrations in western lowland gorillas (Gorilla gorilla gorilla), and all did so using serum. Anesthesia is typically required to collect blood samples from zoo-housed gorillas, limiting sampling frequency and restricting samples to the fasted state. The ability to measure insulin levels in saliva would eliminate these constraints and provide a minimally invasive means for monitoring this hormone. The purpose of this study was to analytically and biologically validate the measurement of insulin in saliva of western lowland gorillas using a commercially available enzyme immunoassay. For validation, an oral sugar test was conducted on five adult gorillas residing at Cleveland Metroparks Zoo. Such assessments are common practice in both human and equine medicine to evaluate the body's insulin response to ingestion of sugars. The test involved measuring salivary insulin at timed intervals before and after gorillas consumed doses of sugar. Salivary insulin levels increased from 15 min post-sugar ingestion and peaked after 90 to 120 min. One female had a high response and peaked at 990.21 mU/L. The other four gorillas had peaks between 49.82 and 167.04 mU/L. The assessment provided a biological validation for the measurement of salivary insulin in western lowland gorillas.

Gestational diabetes mellitus - more than the eye can see - a warning sign for future maternal health with transgenerational impact

Gestational diabetes mellitus (GDM) is regarded by many as maternal maladaptation to physiological insulin resistance during the second half of pregnancy. However, recent evidence indicates that alterations in carbohydrate metabolism can already be detected in early pregnancy. This observation, the increasing prevalence of GDM, and the significant short and long-term implications for the mother and offspring call for reevaluation of the conceptual paradigm of GDM as a syndrome. This review will present evidence for the syndromic nature of GDM and the controversies regarding screening, diagnosis, management, and treatment.

NRF2 deficiency leads to inadequate beta cell adaptation during pregnancy and gestational diabetes

The late stages of mammalian pregnancy are accompanied by a mild increase in insulin resistance likely due to enhanced glucose demand of the growing fetus. Therefore, as an adaptive process to maintain euglycemia during pregnancy, maternal β-cell mass expands leading to increased insulin release. Defects in functional β-cell adaptive expansion during pregnancy can lead to gestational diabetes mellitus (GDM). While the exact mechanisms that promote GDM are poorly understood, GDM is associated with inadequate functional β-cell mass expansion and with a systematic increase of oxidative stress. Here, we show that NRF2 levels are upregulated in mouse β-cells at gestational day 15 (GD15). Inducible β-cell-specific Nrf2 deleted (βNrf2KO) mice display reduced β-cell proliferation, increased β-cell oxidative stress and lipid peroxidation, compromised β-cell function, and elevated β-cell death, leading to impaired β-cell mass expansion and dysregulated glucose homeostasis towards the end of pregnancy. Importantly, the gestational hormone 17-β-estradiol (E2) increases NRF2 levels, and downregulation of NRF2 suppresses E2-induced protection of β-cells against oxidative stress, suggesting that E2 exerts its antioxidant effects through activation of NRF2 signaling in β-cells. Collectively, these data highlight the critical role of NRF2 in regulating oxidative stress during the adaptive response of β-cells in pregnancy and identify NRF2 as a potential therapeutic target for GDM treatment.

A specific metabolomic and lipidomic signature reveals the postpartum resolution of gestational diabetes mellitus or its evolution to type 2 diabetes in rat

Gestational diabetes mellitus (GDM) represents a major public health concern due to adverse maternal postpartum and long-term outcomes. Current strategies to manage GDM fail to reduce the maternal risk to develop later impaired glucose tolerance (IGT) and type 2 diabetes (T2D). In a rodent model of diet-induced GDM without obesity, we explored the perinatal metabolic adaptations in dams with gestational IGT followed by either persistent or resolved postpartum IGT. Female Sprague-Dawley rats were fed a high-fat high-sucrose (HFHS) or a chow [control group (CTL)] diet, 1 wk before mating and throughout gestation (G). Following parturition, HFHS dams were randomized to two subgroups: one switched to a chow diet and the other one maintained on an HFHS diet throughout lactation (L). Oral glucose tolerance tests (OGTTs) were performed, and plasma metabolome-lipidome were characterized at G12 and L12. We found that 1) in GDM-pregnant dams, IGT was associated with incomplete fatty acid oxidation (FAO), enhanced gluconeogenesis, altered insulin signaling, and oxidative stress; 2) improved glucose tolerance postpartum seemed to restore complete FAO along with elevation of nervonic acid-containing sphingomyelins, assumed to impart β-cell protection; and 3) persistence of IGT after delivery was associated with metabolites known to predict the early onset of insulin and leptin resistance, with maintained liver dysfunction. Our findings shed light on the impact of postpartum IGT evolution on maternal metabolic outcome after an episode of GDM. They suggest innovative strategies, implemented shortly after delivery and targeted on these biomarkers, should be explored to curb or delay the transition from GDM to T2D in these mothers.NEW & NOTEWORTHY Specific metabolomic/lipidomic features are associated with GDM postpartum outcomes. GDM-pregnant dams exhibit partial fatty acid oxidation and boosted gluconeogenesis. Resolution of postpartum IGT relies on nervonic acid-sphingomyelin, a β-cell protector. Postpartum IGT persistence suggests muscle insulin resistance and liver dysfunction.

Biomarkers of Gestational Diabetes Mellitus: Mechanisms, Advances, and Clinical Utility

Gestational diabetes mellitus (GDM) continues to pose a significant challenge to maternal and fetal health, driving the need for advanced diagnostic and therapeutic strategies. Biomarker discovery has proven essential for early detection, mechanistic insights, and targeted interventions. This review provides an in-depth examination of biomarkers related to GDM, focusing on glucose metabolism, insulin resistance, inflammatory signaling, adipokines, oxidative stress markers, and genetic/epigenetic determinants. We also evaluate novel biomarkers emerging from omics technologies and their translational potential in clinical practice. Additionally, we explore the role of microRNAs and extracellular vesicles as emerging biomarkers that could offer new perspectives on GDM pathophysiology. Integration of these biomarkers into predictive models holds the potential to improve risk assessment and patient health outcomes.

Longer Interpregnancy Interval Is Associated with Gestational Diabetes Mellitus Recurrence

OBJECTIVE

 This study aimed to evaluate the effect of interpregnancy interval (IPI) on the gestational diabetes mellitus (GDM) recurrence rate in the subsequent pregnancies following an initial pregnancy complicated by GDM.

STUDY DESIGN

 A multicenter, retrospective cohort study was conducted. The study included women diagnosed with GDM during their index pregnancy who subsequently delivered between 26 and 42 weeks of gestation from 2005 to 2021. The study population was categorized into eight groups according to their IPIs: up to 3, 3-5, 6-11, 12-17, 18-23, 24-35, 36-47, and over 48 months. We examined the recurrence rate of GDM in the different groups while comparing it to the 18-23-month group that was defined as the reference group. Statistical analyses included univariate analyses and multiple logistic regression.

RESULTS

 Out of 3,532 women who were included in the study, 1,776 (50.3%) experienced GDM recurrence in subsequent pregnancy. The recurrence rate was 44.6% for women IPI <6 months, 42.6% for women IPI of 6-11 months, 48.0% for women IPI of 12-17 months, 49.7% for women IPI of 18-23 months, 58.0% for women IPI of 24-47 months, and 62.6% for women IPI above 48 months. Multivariable logistic regression revealed that IPIs of 24-47 months and over 48 months were significantly associated with higher recurrence rates as compared with the 18-23-month reference group (adjusted odds ratio [aOR], 95% confidence interval [CI]: 1.66 [1.04-2.64] and 3.15 [1.07-9.29], respectively). This analysis also revealed other independent risk factors for GDM recurrence, including medication-controlled GDM in the index pregnancy, obesity, maternal age, parity, and gravidity.

CONCLUSION

 Longer IPIs (over 24 months) are associated with an increased risk of GDM recurrence in subsequent pregnancies. These findings suggest that clinicians should consider IPI while managing postpartum care and planning future pregnancies for women with a history of GDM.

KEY POINTS

· Longer IPIs (over 24 months) are associated with an increased risk of GDM recurrence.. · Clinicians should consider IPI while managing postpartum care for women with a history of GDM.. · GDM A1, obesity, maternal age, parity, and gravidity were found as risk factors for GDM recurrence..

Evaluation of Maternal Factors Affecting Postpartum Insulin Resistance Markers in Mothers with Gestational Diabetes-A Case-Control Study

BACKGROUND

Gestational diabetes mellitus (GDM) is defined by an insufficient insulin response to counteract the insulin resistance (IR) that arises from the physiological adaptations associated with pregnancy. However, the pathophysiology of IR is complex and unclear, as it encompasses elements such as epigenetics, environmental factors, modifiable lifestyle factors, and psychosocial factors.

AIM

The objective of this study was to evaluate the influence of GDM and other maternal factors on IR markers in comparison to mothers with normal glucose tolerance during pregnancy in the first week postpartum.

MATERIAL AND METHODS

The study population comprised 70 participants, including mothers with gestational diabetes who were treated with a diet and physical activity (GDM G1), with insulin (GDM G2), and a control group of healthy mothers without gestational diabetes (non-GDM). A series of statistical techniques were employed to facilitate the comparison of data between the study groups, with the objective of identifying potential associations with maternal factors. A taxonomic analysis was conducted using the following factors: classification by study group, a history of hypothyroidism in the maternal medical interview, and maternal gestational weight gain, which were identified as the best-fitting predictors.

RESULTS

The analysis resulted in the identification of four clusters of patients. Comparison of the insulin resistance markers between mothers assigned to the abovementioned clusters showed differences in the incidence of excessive weight loss and in the results of glucose screening tests during pregnancy. Also, differences concerning fasting glucose levels in the first and second/third trimesters of pregnancy and glucose levels at 1 h post-OGTT were found. For the clusters, the results of the HOMA-IR and the QUICKI did not show any differences in the first week after delivery (p > 0.05). HbA1c results varied significantly.

CONCLUSIONS

Degree of glucose metabolism disorders, hypothyroidism, and weight gain in pregnancy influence maternal insulin resistance markers in the first week postpartum. Additionally, gestational weight fluctuation has a significant influence on the outcome of pregnancy, particularly with regard to fetal growth and, consequently, the infant's birth weight and adipose tissue accumulation.

Linking the reversal of gestational insulin resistance to postpartum depression

BACKGROUND

Postpartum depression (PPD) constitutes a significant mental health disorder affecting almost one fifth of pregnancies globally. Despite extensive research, the precise etiological mechanisms underlying PPD remain elusive. However, several risk factors like genetic predisposition, hormonal fluctuations, and stress-related environmental and psychosocial triggers have been found to be implicated in its development. MAIN: Recently, an increased risk of PPD has been reported to be associated with gestational diabetes mellitus (GDM), which is characterized by the disruption of glucose metabolism, primarily attributed to the emergence of insulin resistance (IR). While IR during pregnancy seems to be an evolutionary adaptative mechanism to handle the profound metabolic alterations during pregnancy, its subsequent resolution following delivery necessitates a reconfiguration of the metabolic landscape in both peripheral tissues and the central nervous system (CNS). Considering the pivotal roles of energy metabolism, particularly glucose metabolism, in CNS functions, we propose a novel model that such pronounced changes in IR and the associated glucose metabolism seen postpartum might account for PPD development. This concept is based on the profound influences from insulin and glucose metabolism on brain functions, potentially via modulating neurotransmitter actions of dopamine and serotonin. Their sudden postpartum disruption is likely to be linked to mood changes, as observed in PPD.

CONCLUSIONS

The detailed pathogenesis of PPD might be multifactorial and still remains to be fully elucidated. Nevertheless, our hypothesis might account in part for an additional etiological factor to PPD development. If our concept is validated, it can provide guidance for future PPD prevention, diagnosis, and intervention.

The Impact of a Lifestyle Intervention on Cardiometabolic Risk Factors among Postpartum Hispanic Women with Overweight and Obesity in a Randomized Controlled Trial (Proyecto Mamá)

INTRODUCTION

Maternal overweight or obesity has been associated with metabolic syndrome through 1 year postpartum, but it remains unknown whether a culturally-modified, motivationally-targeted, and individually-tailored Lifestyle Intervention could improve postpartum cardiometabolic health among Hispanic women with overweight or obesity.

METHODS

Proyecto Mamá was a randomized controlled trial conducted in Western Massachusetts from 2014 to 2020 in which Hispanic women with overweight/obesity were randomized to a Lifestyle Intervention (LI) involving diet and exercise or to a comparison Health and Wellness Intervention (HW). Biomarkers of cardiovascular risk (i.e., lipids, C-reactive protein) and insulin resistance (fasting insulin, glucose, HbA1c, homeostasis model assessment [HOMA-IR], leptin, adiponectin) were measured at baseline (early pregnancy), mid-pregnancy, and 6 weeks, 6 months, and 12 months postpartum. Generalized linear mixed effect models were used to evaluate differences in the change in biomarkers over the course of postpartum follow-up time.

RESULTS

In intent-to-treat analyses among eligible women (LI; n=51, HW; n=58) there were no significant differences in changes in biomarkers of CVD risk or insulin resistance over the postpartum year; for example, the intervention effect for total cholesterol was 6.98 (SE: 6.36, p=0.27) and for HbA1c was -0.01 (SE: 0.4, p=0.85). In pooled analyses, regardless of intervention arm, women who participated in any vigorous activity had less of an increase in HbA1c (intervention effect = -0.17, SE: 0.05, p=0.002) compared to those with no vigorous activity, and similarly beneficial associations with other cardiovascular risk biomarkers (p<0.05).

DISCUSSION

Women who participated in vigorous activity, regardless of their assigned intervention arm, had more favorable changes in biomarkers of insulin resistance.

Myths and methodologies: Assessing glycaemic control and associated regulatory mechanisms in human physiology research

Accurate measurements of glycaemic control and the underpinning regulatory mechanisms are vital in human physiology research. Glycaemic control is the maintenance of blood glucose concentrations within optimal levels and is governed by physiological variables including insulin sensitivity, glucose tolerance and β-cell function. These can be measured with a plethora of methods, all with their own benefits and limitations. Deciding on the best method to use is challenging and depends on the specific research question(s). This review therefore discusses the theory and procedure, validity and reliability and any special considerations of a range common methods used to measure glycaemic control, insulin sensitivity, glucose tolerance and β-cell function. Methods reviewed include glycosylated haemoglobin, continuous glucose monitors, the oral glucose tolerance test, mixed meal tolerance test, hyperinsulinaemic euglycaemic clamp, hyperglycaemic clamp, intravenous glucose tolerance test and indices derived from both fasting concentrations and the oral glucose tolerance test. This review aims to help direct understanding, assessment and decisions regarding which method to use based on specific physiology-related research questions.

The impact of a culturally adapted lifestyle intervention on the glycaemic profile of mothers with GDM one year after delivery - a community-based, cluster randomized trial in Sri Lanka

BACKGROUND

A woman with a history of GDM has a high risk of developing type two diabetes (T2DM) in her future life. Lifestyle modifications are known to attenuate the progression of GDM to T2DM. Therefore, the aim of this study was to assess the impact of a simple, cost effective, culturally acceptable lifestyle intervention programme on the trajectory towards T2DM in women with a history of GDM.

METHODS

This cluster randomized trial was conducted in 100 postpartum women in three selected districts of Sri Lanka. The subjects were divided into intervention (n = 50) and control groups (n = 50) by cluster randomization method. A culturally adapted protocol (comprised of dietary and physical activity modifications) was administered to the intervention group. The glycemic profile was assessed using fasting and 2-hour post-OGTT plasma glucose and HbA1c, and insulin resistance by HOMA-IR at baseline and after one year of intervention.

RESULTS

The mean age (SD) of the subjects in the intervention and control groups were 33.0 (5.1) and 34.3 (6.5) years respectively. All glycemic and insulin resistance parameters (i.e. Fasting plasma glucose- FPG, 2-hour post-OGTT plasma glucose, HbA1c and HOMA-ir) were comparable (p > 0.05) between the two groups at baseline. FPG, 2 h post OGTT, HbA1c and HOMA-ir values between intervention vs. control (p) at 12 months were 87.3 vs. 123.2 (< 0.01); 106.5 vs. 156.1 (0.01); 5.3 vs. 6.8 (< 0.01) and 0.9 vs. 2.3 (< 0.01) respectively. All glycemic parameters showed a significant reduction in the intervention group at 12 months compared to baseline. In contrast, the control group showed a significant increase in FPG, 2-hour post-OGTT plasma glucose and HbA1c at 12 months compared to baseline. In multiple linear regression model adjusted for age, parity and family history, the control group showed an approximately 33 times risk of developing insulin resistance compared to the intervention group.

CONCLUSION

The culturally acceptable and individualized lifestyle intervention was able to produce remarkable reductions in glycaemic and insulin resistance parameters among postpartum women with a history of GDM.

TRIAL REGISTRATION

Ethical clearance was obtained from the Ethics Review Committee of the University of Sri Jayewardenepura, Sri Lanka (ERC 52/14), Sri Lanka Clinical trial registration number Sri Lanka Clinical Trials Registry (SLCTR/2015/021 date 25.09.2015).

Insulin Blood Levels in Gestational Diabetes Mellitus in Relation to Ethnicity and Age in the Kingdom of Bahrain: A Cross-Sectional Study

BACKGROUND

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy. It may be attributed to certain placental hormones during pregnancy which render insulin less effective. Our study aimed to focus on the levels of insulin in gestational diabetic women in the Kingdom of Bahrain as compared with non-diabetic pregnant women. Furthermore, we studied the correlation between insulin levels by ethnicity and age of the pregnant women.  Methods: A cross-sectional study was conducted on 75 pregnant participants: 41 with GDM (test group) and 34 without GDM (control group). Insulin levels were determined in patients with GDM and compared to non-diabetic pregnant women. A comparison between Bahraini and non-Bahraini women was carried out in two different age groups: below and above 30 years of age. P values < 0.05 were considered significant.

RESULTS

The results showed higher mean values of fasting blood glucose (FBG), random blood glucose (RBG), and insulin levels in the test group when compared to the control group. There was no significant difference in FBG, RBG, and insulin levels among Bahraini women with GDM and non-Bahraini women (Indian, Pakistani. Bengali, and Filipino) with GDM. Age, less than 30 vs more than 30 years, had no significant effect on women with GDM.

CONCLUSION

Insulin levels were higher in pregnant women with GDM irrespective of their ethnicity or age. The lack of blood glucose control in GDM even in the presence of high insulin secretion may suggest loss of insulin effectiveness due to other factors such as stress and lactogenic placental hormones.

Improvement of insulin sensitivity by dietary fiber consumption during late pregnant sows is associated with gut microbiota regulation of tryptophan metabolism

BACKGROUND

Dietary fiber (DF) consumption was reported to improve insulin sensitivity, change the tryptophan metabolism, and alter the gut microbiota. Herein, this study aimed to investigate the effects of DF consumption on insulin sensitivity, tryptophan metabolism, and gut microbiota composition in sows during late pregnancy, and explore the relationship between tryptophan metabolites and insulin sensitivity regulated by DF supplementation.

RESULTS

Twelve sows were randomly assigned to two dietary treatment groups (six/group): the low-fiber (LF) group, which was fed a basal diet, and the high-fiber (HF) group, which was fed the basal diet supplemented with 22.60 g/kg inulin and 181.60 g/kg cellulose. During late pregnancy, meal test, glucose tolerance test, and insulin challenge test were used to investigate the insulin sensitivity of sows, using the percutaneous brachiocephalic vein catheterization technique. High DF consumption resulted in improved insulin sensitivity, especially during the second and third trimesters, and promoted serotonin production from tryptophan. Additionally, plasma serotonin concentration was positively correlated with the insulin sensitivity index during late pregnancy. Moreover, DF consumption elevated fecal short-chain fatty acid (SCFA) concentrations, altered fecal microbial diversity, and increased the abundances of Rikenellaceae_RC9_gut_group, Alloprevotella, Parabacteroides, Roseburia, and Sphaerochaeta, which were positively correlated to plasma serotonin concentration.

CONCLUSIONS

DF consumption improved insulin sensitivity during late pregnancy in sows, which improved microbial diversity in fecal samples and increased fecal SCFA concentrations, resulting in a positive correlation with plasma serotonin level.

Protein Profiling of Placental Extracellular Vesicles in Gestational Diabetes Mellitus

Throughout pregnancy, some degree of insulin resistance is necessary to divert glucose towards the developing foetus. In gestational diabetes mellitus (GDM), insulin resistance is exacerbated in combination with insulin deficiency, causing new-onset maternal hyperglycaemia. The rapid reversal of insulin resistance following delivery strongly implicates the placenta in GDM pathogenesis. In this case-control study, we investigated the proteomic cargo of human syncytiotrophoblast-derived extracellular vesicles (STBEVs), which facilitate maternal-fetal signalling during pregnancy, in a UK-based cohort comprising patients with a gestational age of 38-40 weeks. Medium/large (m/l) and small (s) STBEVs were isolated from GDM (n = 4) and normal (n = 5) placentae using ex vivo dual-lobe perfusion and subjected to mass spectrometry. Bioinformatics were used to identify differentially carried proteins and mechanistic pathways. In m/lSTBEVs, 56 proteins were differently expressed while in sSTBEVs, no proteins reached statistical difference. Differences were also observed in the proteomic cargo between m/lSTBEVs and sSTBEVs, indicating that the two subtypes of STBEVs may have divergent modes of action and downstream effects. In silico functional enrichment analysis of differentially expressed proteins in m/lSTBEVs from GDM and normal pregnancy found positive regulation of cytoskeleton organisation as the most significantly enriched biological process. This work presents the first comparison of two populations of STBEVs' protein cargos (m/l and sSTBEVs) from GDM and normal pregnancy isolated using placenta perfusion. Further investigation of differentially expressed proteins may contribute to an understanding of GDM pathogenesis and the development of novel diagnostic and therapeutic tools.

The yield of early-pregnancy homeostasis of model assessment -insulin resistance (HOMA-IR) for predicting gestational diabetes mellitus in different body mass index and age groups

BACKGROUND

Early prediction of gestational diabetes mellitus(GDM) can be beneficial for lifestyle modifications to prevent GDM. The aim of this study was to investigate the predictive values of Homeostasis of Model Assessment -Insulin Resistance (HOMA-IR) in early pregnancy to predict GDM development in different body mass index (BMI) and age risk categories.

MATERIALS AND METHODS

This study is part of the Qazvin Maternal and Neonatal Metabolic Study (QMNMS) in Iran (2018-2021). In this prospective longitudinal study, pregnant women with a gestational age ≤ 14 weeks were enrolled in the study using convenience sampling method and were followed up until delivery to investigate risk factors for maternal and neonatal complications. Data collection was done using questionnaires. Serum sampling was done at a gestational age ≤ 14 weeks and sera were frozen until the end of study. GDM was diagnosed at 24-28 weeks of pregnancy using 75gr oral glucose tolerance test. Fasting blood glucose and insulin were measured in sera taken during early pregnancy in 583 participants. The Mann-Whitney U test, independent t-test, and Chi-square test were used for comparing variables between groups. The logistic regression analysis was used to examine the independent association of HOMA-IR with GDM development and receiver operating characteristic analysis was used for finding the best cut-off of HOMA-IR for predicting GDM.

RESULTS

GDM was developed in 90 (15.4%) of the participants. The third HOMA-IR tertile was independently associated with 3.2 times higher GDM occurrence (95% CI:1.6-6.2, P = 0.001). Despite the high prevalence of GDM in advanced maternal age (GDM rate = 28.4%), HOMA-IR had no association with GDM occurrence in this high-risk group. In both normal BMI and overweight/obese groups, HOMA-IR was a moderate predictor of GDM development (AUC = 0.638, P = 0.005 and AUC = 0.622, P = 0.008, respectively). However, the best cut-off for predicting GDM was 2.06 (sensitivity 67.5%, specificity 61.1%) in normal BMI and 3.13 (sensitivity 64.6%, specificity61.8%) in overweight/obese BMI.

CONCLUSION

The present study revealed the necessity of considering the BMI and age risk groups when using the HOMA-IR index to predict GDM. Using lower cut-offs is more accurate for women with a normal BMI. In the advanced maternal age, there is no yield of HOMA-IR for predicting GDM.

Growth differentiation factor‑15 in patients with gestational diabetes mellitus and its relationship with microalbuminuria

Gestational diabetes mellitus (GDM) is a common pregnancy-related complication and growth differentiation factor-15 (GDF-15) is involved in a number of diseases; therefore, the aim of the present study was to investigate the level and clinical significance of serum GDF-15 levels in patients with GDM. A total of 237 pregnant women at 20-24 weeks of gestation were selected and assigned to a normal pregnancy group (70 patients) and a GDM group (167 patients) according to the presence or absence of GDM. The general clinical data of the two groups were collected. Fasting plasma glucose, 1-h plasma glucose, 2-h plasma glucose, glycated hemoglobin, fasting insulin, 24-h urinary albumin and serum GDF-15 levels were measured. The results showed that the body mass index (BMI) of the GDM group was higher than that of the normal pregnancy group. Fasting plasma glucose, 1-h plasma glucose, 2-h plasma glucose, fasting insulin, glycated hemoglobin and GDF-15 levels and the positive rate of microalbuminuria were significantly higher in the GDM group compared with the normal pregnancy group. GDF-15 levels were positively correlated with BMI, fasting plasma glucose, glycated hemoglobin, homeostasis model assessment-insulin resistance and fasting insulin levels. Logistic regression analysis suggested that elevated GDF-15 levels are an independent risk factor for microalbuminuria. In conclusion, serum GDF-15 levels are strongly associated with GDM and elevated GDF-15 levels are an independent risk factor for microalbuminuria. Serum GDF-15 may act as a novel biomarker for predicting microalbuminuria in GDM patients.

The MPRINT Hub Data, Model, Knowledge and Research Coordination Center: Bridging the gap in maternal-pediatric therapeutics research through data integration and pharmacometrics

Maternal and pediatric populations have historically been considered "therapeutic orphans" due to their limited inclusion in clinical trials. Physiologic changes during pregnancy and lactation and growth and maturation of children alter pharmacokinetics (PK) and pharmacodynamics (PD) of drugs. Precision therapy in these populations requires knowledge of these effects. Efforts to enhance maternal and pediatric participation in clinical studies have increased over the past few decades. However, studies supporting precision therapeutics in these populations are often small and, in isolation, may have limited impact. Integration of data from various studies, for example through physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) modeling or bioinformatics approaches, can augment the value of data from these studies, and help identify gaps in understanding. To catalyze research in maternal and pediatric precision therapeutics, the Obstetric and Pediatric Pharmacology and Therapeutics Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) established the Maternal and Pediatric Precision in Therapeutics (MPRINT) Hub. Herein, we provide an overview of the status of maternal-pediatric therapeutics research and introduce the Indiana University-Ohio State University MPRINT Hub Data, Model, Knowledge and Research Coordination Center (DMKRCC), which aims to facilitate research in maternal and pediatric precision therapeutics through the integration and assessment of existing knowledge, supporting pharmacometrics and clinical trials design, development of new real-world evidence resources, educational initiatives, and building collaborations among public and private partners, including other NICHD-funded networks. By fostering use of existing data and resources, the DMKRCC will identify critical gaps in knowledge and support efforts to overcome these gaps to enhance maternal-pediatric precision therapeutics.

Alpha-linolenic acid modulates systemic and adipose tissue-specific insulin sensitivity, inflammation, and the endocannabinoid system in dairy cows

Metabolic disorders are often linked to alterations in insulin signaling. Omega-3 (n-3) fatty acids modulate immunometabolic responses; thus, we examined the effects of peripartum n-3 on systemic and adipose tissue (AT)-specific insulin sensitivity, immune function, and the endocannabinoid system (ECS) in dairy cows. Cows were supplemented peripartum with saturated fat (CTL) or flaxseed supplement rich in alpha-linolenic acid (ALA). Blood immunometabolic biomarkers were examined, and at 5-8 d postpartum (PP), an intravenous glucose-tolerance-test (GTT) and AT biopsies were performed. Insulin sensitivity in AT was assessed by phosphoproteomics and proteomics. Peripartum n-3 reduced the plasma concentrations of Interleukin-6 (IL-6) and IL-17α, lowered the percentage of white blood cells PP, and reduced inflammatory proteins in AT. Systemic insulin sensitivity was higher in ALA than in CTL. In AT, the top canonical pathways, according to the differential phosphoproteome in ALA, were protein-kinase-A signaling and insulin-receptor signaling; network analysis and immunoblots validated the lower phosphorylation of protein kinase B (Akt), and lower abundance of insulin receptor, together suggesting reduced insulin sensitivity in ALA AT. The n-3 reduced the plasma concentrations of ECS-associated ligands, and lowered the abundances of cannabinoid-1-receptor and monoglycerol-lipase in peripheral blood mononuclear cells PP. Peripartum ALA supplementation in dairy cows improved systemic insulin sensitivity and immune function, reduced ECS components, and had tissue-specific effects on insulin-sensitivity in AT, possibly counter-balancing the systemic responses.

Hyperglycemia in Pregnancy and Women's Health in the 21st Century

Hyperglycemia is the commonest medical condition affecting pregnancy and its incidence is increasing globally in parallel with the twin epidemics of diabetes and obesity. Both pre-pregnancy diabetes and gestational diabetes are associated with short term pregnancy complications, with the risk of immediate complications generally broadly rising with more severe hyperglycemia. In this article we firstly consider these risks and their optimal management during pregnancy and then broaden our scope to consider the long-term implications of hyperglycemia in pregnancy as it relates to overall maternal and offspring health in a life course perspective.

Sexual dimorphism in the molecular mechanisms of insulin resistance during a critical developmental window in Wistar rats

Background

Insulin resistance (IR) is a condition in which the response of organs to insulin is impaired. IR is an early marker of metabolic dysfunction. However, IR also appears in physiological contexts during critical developmental windows. The molecular mechanisms of physiological IR are largely unknown in both sexes. Sexual dimorphism in insulin sensitivity is observed since early stages of development. We propose that during periods of accelerated growth, such as around weaning, at postnatal day 20 (p20) in rats, the kinase S6K1 is overactivated and induces impairment of insulin signaling in its target organs. This work aimed to characterize IR at p20, determine its underlying mechanisms, and identify whether sexual dimorphism in physiological IR occurs during this stage.

Methods

We determined systemic insulin sensitivity through insulin tolerance tests, glucose tolerance tests, and blood glucose and insulin levels under fasting and fed conditions at p20 and adult male and female Wistar rats. Furthermore, we quantified levels of S6K1 phosphorylated at threonine 389 (T389) (active form) and its target IRS1 phosphorylated at serine 1101 (S1101) (inhibited form). In addition, we assessed insulin signal transduction by measuring levels of Akt phosphorylated at serine 473 (S473) (active form) in white adipose tissue and skeletal muscle through western blot. Finally, we determined the presence and function of GLUT4 in the plasma membrane by measuring the glucose uptake of adipocytes. Results were compared using two-way ANOVA (With age and sex as factors) and one-way ANOVA with post hoc Tukey’s tests or t-student test in each corresponding case. Statistical significance was considered for P values < 0.05.

Results

We found that both male and female p20 rats have elevated levels of glucose and insulin, low systemic insulin sensitivity, and glucose intolerance. We identified sex- and tissue-related differences in the activation of insulin signaling proteins in p20 rats compared to adult rats.

Conclusions

Male and female p20 rats present physiological insulin resistance with differences in the protein activation of insulin signaling. This suggests that S6K1 overactivation and the resulting IRS1 inhibition by phosphorylation at S1101 may modulate to insulin sensitivity in a sex- and tissue-specific manner.

Relationship between different hepatitis B virus infection status and gestational diabetes mellitus prevalence among pregnant women with chronic HBV infection: A retrospective study

To investigate the relationships between different hepatitis B virus (HBV) infection status and gestational diabetes mellitus (GDM) and analyse the potential risk factors, we conducted an observational retrospective study in HBV-infected pregnant women to compare the differences of GDM prevalence and clinical outcomes between groups divided by HBV infection status. Spearman's correlation coefficient was used to evaluate the correlations among hepatitis B e antigen (HBeAg), HBV DNA and liver function. Logistic regression model was used to analyse the risk factors. In all, 1390 HBsAg-positive pregnant women were enrolled. HBeAg titre and HBV DNA, ALT and AST were correlated (r = 0.743, p < 0.001; r = 0.813, p < 0.001). Overall GDM prevalence was 21%. GDM prevalence of HBV-infected women with abnormal liver function was higher than those with normal liver function (26.8% vs. 20%, p = 0.027). Age over 35 years and abnormal liver function over 5 times ULN and 1-2 times ULN were independent risk factors for GDM prevalence with odds ratio (OR) of 1.858 (95% CI 1.227-2.815), 1.589 (95% CI 1.023-2.468) and 2.203 (95% CI 1.029-4.718), respectively. GDM prevalence in HBV-infected pregnancies with abnormal liver function was higher than those with normal liver function. Age over 35 years and abnormal liver function were independent risk factors for GDM in HBV-infected women.

NLRP3 inflammasome activation in gestational diabetes mellitus placentas is associated with hydrogen sulfide synthetase deficiency

The placenta may play a key role in the activation of inflammation and initiation of insulin resistance (IR) during gestational diabetes mellitus (GDM) pathogenesis. Interleukin (IL)-1β and IL-18, regulated by NLR family pyrin domain containing-3 (NLRP3) inflammasome, are important inflammatory cytokines in the initiation of maternal IR during GDM. However, the mechanism responsible for the regulatory of NLRP3 inflammasome in placenta remains unknown. Hydrogen sulfide (H₂S) exerts anti-inflammatory function partially via suppressing the activation of the NLPR3 inflammasome. The present study aimed to investigate the role of NLRP3 inflammasome, H₂S synthetase cystathionine-γ-lyase (CSE) and cystathionine-β-synthetase (CBS) in placenta in the pathogenesis of GDM. Clinical placenta samples were collected from pregnant women with GDM (n=16) and healthy pregnant women at term (n=16). Western blot analysis was performed to detect the protein expression levels of NLRP3, cleaved caspase-1, CBS and CSE in the placenta samples. Pearson's correlation analysis was performed to assess the correlation between NLRP3 inflammasome and H₂S synthetase. Human placental cells were cultured and treated with different concentrations of NaHS (0, 10, 25 and 50 nmol/l) or L-cysteine (0, 0.25, 0.50 and 1.00 mmol/l). In addition, western blot analysis was performed to detect the protein expression levels of NLRP3 and cleaved caspase-1, while ELISA was performed to measure the production of IL-1β and IL-18 in the culture media. The results demonstrated that the expression levels of NLRP3 and cleaved caspase-1 increased, while the expression levels of CBS and CSE decreased in the placenta samples. In addition, the expression levels of NLRP3 and cleaved caspase-1 were inversely correlated with the expression levels of CBS and CSE. Notably, NaHS and L-cysteine significantly suppressed the expression levels of NLRP3 and cleaved caspase-1, and the production of IL-1 and IL-18 in human placental cells. Taken together, the results of the present study suggest that H₂S synthetase deficiency in placenta may contribute to excessive activation of NLRP3 inflammasome in GDM.

Adverse metabolic outcomes in the early and late postpartum after gestational diabetes are broader than glucose control

INTRODUCTION

Gestational diabetes mellitus is associated with an increased cardiovascular risk. To better target preventive measures, we performed an in-depth characterization of cardiometabolic risk factors in a cohort of women with gestational diabetes in the early (6-8 weeks) and late (1 year) postpartum.

RESEARCH DESIGN AND METHODS

Prospective cohort of 622 women followed in a university gestational diabetes clinic between 2011 and 2017. 162 patients who attended the late postpartum visit were analyzed in a nested long-term cohort starting in 2015. Metabolic syndrome (MetS) was based on the International Diabetes Federation definition, and then having at least two additional criteria of the MetS (blood pressure, triglycerides, high-density lipoprotein (HDL) cholesterol, plasma glucose above or below the International Diabetes Federation cut-offs).

RESULTS

Compared with prepregnancy, weight retention was 4.8±6.0 kg in the early postpartum, and the prevalence of obesity, pre-diabetes, MetS-body mass index (BMI) and MetS-waist circumference (WC) were 28.8%, 28.9%, 10.3% and 23.8%, respectively. Compared with the early postpartum, weight did not change and waist circumference decreased by 2.6±0.6 cm in the late postpartum. However, the prevalence of obesity, pre-diabetes, MetS-WC and MetS-BMI increased (relative increase: 11% for obesity, 82% for pre-diabetes, 50% for MetS-WC, 100% for MetS-BMI; all p≤0.001).Predictors for obesity were the use of glucose-lowering treatment during pregnancy and the prepregnancy BMI. Predictors for pre-diabetes were the early postpartum fasting glucose value and family history of diabetes. Finally, systolic blood pressure in pregnancy and in the early postpartum, the 2-hour post oral glucose tolerance test glycemia and the HDL-cholesterol predicted the development of MetS (all p<0.05).

CONCLUSIONS

The prevalence of metabolic complications increased in the late postpartum, mainly due to an increase in fasting glucose and obesity, although weight did not change. We identified predictors of late postpartum obesity, pre-diabetes and MetS that could lead to high-risk identification and targeted preventions.

Extreme insulin resistance during pregnancy: a therapeutic challenge

SUMMARY

During pregnancy, maternal tissues become increasingly insensitive to insulin in order to liberate nutritional supply to the growing fetus, but occasionally insulin resistance in pregnancy becomes severe and the treatment challenging. We report a rare and clinically difficult case of extreme insulin resistance with daily insulin requirements of 1420 IU/day during pregnancy in an obese 36-year-old woman with type 2 diabetes (T2D) and polycystic ovary syndrome (PCOS). The woman was referred to the outpatient clinic at gestational week 12 + 2 with a hemoglobin A1c (HbA1c) at 59 mmol/mol. Insulin treatment was initiated immediately using Novomix 30, and the doses were progressively increased, peaking at 1420 units/day at week 34 + 4. At week 35 + 0, there was an abrupt fall in insulin requirements, but with no signs of placental insufficiency. At week 36 + 1 a, healthy baby with no hypoglycemia was delivered by cesarean section. Blood samples were taken late in pregnancy to search for causes of extreme insulin resistance and showed high levels of C-peptide, proinsulin, insulin-like growth factor (IGF-1), mannan-binding-lectin (MBL) and leptin. CRP was mildly elevated, but otherwise, levels of inflammatory markers were normal. Insulin antibodies were undetectable, and no mutations in the insulin receptor (INSR) gene were found. The explanation for the severe insulin resistance, in this case, can be ascribed to PCOS, obesity, profound weight gain, hyperleptinemia and inactivity. This is the first case of extreme insulin resistance during pregnancy, with insulin requirements close to 1500 IU/day with a successful outcome, illustrating the importance of a close interdisciplinary collaboration between patient, obstetricians and endocrinologists.

LEARNING POINTS

This is the first case of extreme insulin resistance during pregnancy, with insulin requirements of up to 1420 IU/day with a successful outcome without significant fetal macrosomia and hypoglycemia. Obesity, PCOS, T2D and high levels of leptin and IGF-1 are predictors of severe insulin resistance in pregnancy. A close collaboration between patient, obstetricians and endocrinologists is crucial for tailoring the best possible treatment for pregnant women with diabetes, beneficial for both the mother and her child.