Adipokine levels during the first or early second trimester of pregnancy and subsequent risk of gestational diabetes mellitus: A systematic review

Adiponectin Deficiency Impairs Maternal Metabolic Adaptation to Pregnancy in Mice

Hypoadiponectinemia has been widely observed in patients with gestational diabetes mellitus (GDM). To investigate the causal role of hypoadiponectinemia in GDM, adiponectin gene knockout (Adipoq^-/- ) and wild-type (WT) mice were crossed to produce pregnant mouse models with or without adiponectin deficiency. Adenoviral vector-mediated in vivo transduction was used to reconstitute adiponectin during late pregnancy. Results showed that Adipoq^-/- dams developed glucose intolerance and hyperlipidemia in late pregnancy. Increased fetal body weight was detected in Adipoq^-/- dams. Adiponectin reconstitution abolished these metabolic defects in Adipoq^-/- dams. Hepatic glucose and triglyceride production rates of Adipoq^-/- dams were significantly higher than those of WT dams. Robustly enhanced lipolysis was found in gonadal fat of Adipoq^-/- dams. Interestingly, similar levels of insulin-induced glucose disposal and insulin signaling in metabolically active tissues in Adipoq^-/- and WT dams indicated that maternal adiponectin deficiency does not reduce insulin sensitivity. However, remarkably decreased serum insulin concentrations were observed in Adipoq^-/- dams. Furthermore, β-cell mass, but not glucose-stimulated insulin release, in Adipoq^-/- dams was significantly reduced compared with WT dams. Together, these results demonstrate that adiponectin plays an important role in controlling maternal metabolic adaptation to pregnancy.

Leptin and adiponectin levels in discordant dichorionic twins at 72 hours of age-associations with anthropometric parameters and insulin resistance

BACKGROUND

Insulin resistance (IR) in adults has been associated with intrauterine growth restriction (IUGR). Leptin and adiponectin correlations with anthropometric parameters and IR at 72 h in discordant twins were tested.

METHODS

We included 24 discordant (birth weight discordance ≥20% in relation to the heavier cotwin) and 30 concordant (birth weight discordance ≤10%) twins.

RESULTS

A correlation between leptin (but not adiponectin) level and birth weight (BW), birth length and head circumference in IUGR twins was recorded (p<0.05). Insulin sensitivity (IS) and homeostatic model assessment (HOMA)-IR in IUGR twins were similar to appropriate-for-gestational-age cotwins and unrelated to adipokines. In IUGR twins, adiponectin and insulin associated positively. In larger concordant twins' leptin level correlated with HOMA-IR and insulin.

CONCLUSIONS

Leptin, but not adiponectin, levels correlate positively with anthropometric parameters in IUGR twins. IR in IUGR twins is unrelated to adipokines in the first few days of life.

Maternal obesity and inflammatory mediators: A controversial association

The link between maternal obesity and inflammatory mediators is still unclear. Our aim was to summarize the main findings of recently published studies on this topic. We performed a search in Medline for studies published in the last years on obesity, human pregnancy, and inflammatory mediators. We report the findings of 30 studies. The characteristics and number of participants, study design, gestational age at sample collection, and type of sample varied widely. Approximately two-thirds of them investigated more than one mediator, and 50% included participants in only one trimester of pregnancy. The most frequently investigated mediators were leptin, tumour necrosis factor-alpha (TNF-α), and interleukin (IL)-6. Almost all studies reported an association between maternal obesity, leptin, and C-reactive protein (CRP) serum levels but not with IL-1β and IL-10. The association of IL-6, TNF-α, monocyte chemo-attractant protein-1 (MCP-1), adiponectin, and resistin with maternal obesity is still controversial. To clarify the physiopathological link between maternal obesity and inflammation, more high-quality studies are needed.

Early Pregnancy Biochemical Predictors of Gestational Diabetes Mellitus

PURPOSE OF REVIEW

Universal oral glucose tolerance-based screening is employed to identify pregnant women with gestational diabetes mellitus (GDM), as treatment of this condition decreases the risk of associated complications. A simple and accurate blood test which identifies women at low or high risk for GDM in the first trimester would have the potential to decrease costs and improve outcomes through prevention or treatment. This review summarizes published data on early pregnancy biomarkers which have been tested as predictors of GDM.

RECENT FINDINGS

A large number of first-trimester biochemical predictors of GDM have been reported, mostly in small case-control studies. These include glycemic markers (fasting glucose, post-load glucose, hemoglobin A1C), inflammatory markers (C-reactive protein, tumor necrosis factor-alpha), insulin resistance markers (fasting insulin, sex hormone-binding globulin), adipocyte-derived markers (adiponectin, leptin), placenta-derived markers (follistatin-like-3, placental growth factor, placental exosomes), and others (e.g., glycosylated fibronectin, soluble (pro)renin receptor, alanine aminotransferase, ferritin). A few large studies suggest that first-trimester fasting glucose or hemoglobin A1C may be useful for identifying women who would benefit from early GDM treatment. To translate the findings from observational studies of first-trimester biomarkers for GDM to clinical practice, trials or cost-effectiveness analyses of screening and treatment strategies based on these novel biomarkers are needed.

Blood-based biomarkers of adverse perinatal outcomes in maternal obesity

OBJECTIVE

Increasing maternal weight has been shown to predict adverse perinatal outcome, including increases in the relative risk of fetal death, stillbirth, neonatal death, perinatal death and infant death. In order to better understand the pathophysiological factors associated with obesity during pregnancy, the role of biomarkers associated with adverse outcomes in obese pregnant women is under investigation. The purpose of this review study was to examine potential biomarkers that could serve as effective screening strategies in obese pregnant women to reduce fetal and neonatal morbidity, as well as maternal morbidity.

METHODS

Electronic databases (Pubmed, Embase) were searched for previously published research studies that investigated biomarkers associated with perinatal outcomes in obese pregnant women and the putative mechanisms underlying biomarker effects on pregnancy outcomes.

RESULTS

It is evident that while several biomarkers predict perinatal complications in obese pregnant women, none fulfilled the criteria to be considered clinically useful.

CONCLUSION

There is a critical need for reliable blood-based biomarkers associated with an increased risk of adverse perinatal outcomes in obese pregnant women.

Leptin and adiponectin as predictors of cardiovascular risk after gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is a significant risk factor for cardiovascular disease (CVD) in later life, but the mechanism remains unclear. Adipokine imbalance in the presence of metabolic dysfunction may be a key event in promoting CVD. The aim of the study was to examine the relationships between GDM, cardiovascular risk, and plasma adiponectin, leptin and the leptin/adiponectin (L/A) ratio in pregnancy and at 5 years after the index pregnancy.

METHODS

This population-based prospective cohort included 300 women who had an oral glucose tolerance test (OGTT) during pregnancy. Five years later, the OGTT was repeated along with dual-energy X-ray absorptiometry, lipid analysis, and pulse wave velocity analysis. Fasting adiponectin and leptin levels were measured four times during pregnancy and at follow-up.

RESULTS

We found the L/A ratio higher in GDM women both during pregnancy and follow-up compared to non-GDM women. A high L/A ratio during pregnancy was associated with CV risk based on lipid ratios at follow-up, especially the TG/HDL-C ratio. Further, interaction analysis indicated that an increase in the L/A ratio of 1 unit was associated with a higher CV risk in GDM compared to normal pregnancy. Finally, low adiponectin levels independently predicted increased lipid ratios at follow-up.

CONCLUSIONS

Taken together, our findings suggest that high L/A ratio in pregnancy and in particularly in those with GDM are associated with an unfavorable CVD risk profile during follow-up. Future studies should investigate if a dysregulated leptin and adiponectin profile during pregnancy is associated with atherosclerotic disease during long-term follow-up.

Leptin and adiponectin levels in discordant dichorionic twins at 72 hours of age-associations with anthropometric parameters and insulin resistance

Background:

Insulin resistance (IR) in adults has been associated with intrauterine growth restriction (IUGR). Leptin and adiponectin correlations with anthropometric parameters and IR at 72 h in discordant twins were tested.

Methods:

We included 24 discordant (birth weight discordance ≥20% in relation to the heavier cotwin) and 30 concordant (birth weight discordance ≤10%) twins.

Results:

A correlation between leptin (but not adiponectin) level and birth weight (BW), birth length and head circumference in IUGR twins was recorded (p<0.05). Insulin sensitivity (IS) and homeostatic model assessment (HOMA)-IR in IUGR twins were similar to appropriate-for-gestational-age cotwins and unrelated to adipokines. In IUGR twins, adiponectin and insulin associated positively. In larger concordant twins’ leptin level correlated with HOMA-IR and insulin.

Conclusions:

Leptin, but not adiponectin, levels correlate positively with anthropometric parameters in IUGR twins. IR in IUGR twins is unrelated to adipokines in the first few days of life.

Maternal TSH level and TPOAb status in early pregnancy and their relationship to the risk of gestational diabetes mellitus

Subclinical hypothyroidism is common in pregnant women and often related to adverse pregnancy outcomes, but its relationship with gestational diabetes remains controversial. In particular, the impact of thyroperoxidase antibodies status on the relationship between subclinical hypothyroidism and gestational diabetes is not clear. We investigated the association between combined thyroid stimulating hormone (TSH) level and thyroperoxidase antibodies status in early pregnancy (<20 weeks of gestation) and gestational diabetes mellitus. A total of 7084 pregnant women met the inclusion criteria, which included thyroperoxidase antibodies-positive subclinical hypothyroidism [TSH(H)TPOAb(+)] (n = 78), thyroperoxidase antibodies-negative subclinical hypothyroidism [TSH(H)TPOAb(-)] (n = 281), thyroperoxidase antibodies-positive euthyroidism [TSH(N)TPOAb(+)] (n = 648), and thyroperoxidase antibodies-negative euthyroidism [TSH(N)TPOAb(-)] (n = 6077). Of the 7084 cases included in our study, 1141 cases were diagnosed with gestational diabetes mellitus at 24-28 weeks of pregnancy. The prevalence of gestational diabetes mellitus in TSH(N)TPOAb(-), TSH(H)TPOAb(-), TSH(N)TPOAb(+), and TSH(H)TPOAb(+) was 14.65, 19.57, 24.85, and 46.15 %, respectively. Compared with TSH(N)TPOAb(-) women, the risk of gestational diabetes mellitus was increased in all other groups of women in early pregnancy. After dividing early pregnancy into first and second trimesters, we found that TSH(H)TPOAb(-) women in the first trimester do not show this increase. Our study suggests that subclinical hypothyroidism and thyroperoxidase antibodies-positive euthyroidism in early pregnancy are associated with an increased risk of gestational diabetes mellitus.

Novel Molecules Regulating Energy Homeostasis: Physiology and Regulation by Macronutrient Intake and Weight Loss

Excess energy intake, without a compensatory increase of energy expenditure, leads to obesity. Several molecules are involved in energy homeostasis regulation and new ones are being discovered constantly. Appetite regulating hormones such as ghrelin, peptide tyrosine-tyrosine and amylin or incretins such as the gastric inhibitory polypeptide have been studied extensively while other molecules such as fibroblast growth factor 21, chemerin, irisin, secreted frizzle-related protein-4, total bile acids, and heme oxygenase-1 have been linked to energy homeostasis regulation more recently and the specific role of each one of them has not been fully elucidated. This mini review focuses on the above mentioned molecules and discusses them in relation to their regulation by the macronutrient composition of the diet as well as diet-induced weight loss.

Maternal Hyperleptinemia Improves Offspring Insulin Sensitivity in Mice

Maternal obesity and gestational diabetes are prevalent worldwide. Offspring of mothers with these conditions weigh more and are predisposed to metabolic syndrome. A hallmark of both conditions is maternal hyperleptinemia, but the role of elevated leptin levels during pregnancy on developmental programming is largely unknown. We previously found that offspring of hyperleptinemic mothers weighed less and had increased activity. The goal of this study was to determine whether maternal leptin affects offspring insulin sensitivity by investigating offspring glucose metabolism and lipid accumulation. Offspring from two maternal hyperleptinemic models were compared. The first model of hyperleptinemia is the Lepr(db/+) mouse, which has a mutation in one copy of the gene that encodes the leptin receptor, resulting in a truncated long form of the receptor, and hyperleptinemia. Wild-type females served as the control for the Lepr(db/+) females. For the second hyperleptinemic model, wild-type females were implanted with miniosmotic pumps, which released leptin (350 ng/h) or saline (as the control) just prior to mating and throughout gestation. In the offspring of these dams, we measured glucose tolerance; serum leptin, insulin, and triglyceride levels; liver triglycerides; pancreatic α- and β-cell numbers; body composition; incidence of nonalcoholic fatty liver disease; and the expression of key metabolic genes in the liver and adipose tissue. We found that the offspring of hyperleptinemic dams exhibited improved glucose tolerance, reduced insulin and leptin concentrations, reduced liver triglycerides, and a lower incidence of nonalcoholic fatty liver disease. Overall, maternal hyperleptinemia was beneficial for offspring glucose and lipid metabolism.

Association between maternal serum high mobility group box 1 levels and pregnancy complicated by gestational diabetes mellitus

BACKGROUND AND AIMS

Gestational diabetes mellitus (GDM), is characterized by chronic, low-grade subclinical inflammation with altered production of cytokines and mediators. Recently, a new protein acting as a "danger signal", high mobility group box 1 (HMGB1), that migrates quickly during electrophoresis, has been identified. The aim of our study was to analyze serum levels of HMGB1 in pregnant women, with or without GDM, in the third trimester of pregnancy to evaluate correlation with insulin resistance and other risk factors for GDM.

METHODS AND RESULTS

Seventy five pregnant women positive to the 75 g oral glucose tolerance test (OGTT) were included in the study group and 48 pregnant women who were negative to the screening test, were randomly selected using a computer-generated randomisation table. A significant positive univariate correlation was observed between serum HMGB1 levels, HOMA-IR index, glycaemia values at OGTT and pre-pregnancy BMI. Moreover, logistic regression analysis showed that serum HMGB1 was independent linked to GDM.

CONCLUSION

Our study demonstrated that HMGB1, a marker of chronic inflammation, is associated to GDM and insulin resistance level, in the third trimester of pregnancy.

Prediction and prevention of Gestational Diabetes: an update of recent literature

A diagnosis of Gestational Diabetes (GDM) confers adverse risk to the health of the mother and fetus both in pregnancy and later life. The background rate in pregnancy varies between 2 and 14% with incidences reported to be as high as 40% in obese populations. GDM diagnoses are escalating because of rising numbers of overweight and obesity in the reproductive age group but also because of different screening and diagnostic criteria. Lifestyle modification in those diagnosed with GDM has been proven to be an effective treatment in attenuating the metabolic dysregulation associated with this and potentially avoiding the need for medical therapy with either metformin or insulin. Emerging evidence in previous years suggests lifestyle interventions (dietary±physical activity and behavior modification) either pre-pregnancy or antenatally may reduce the incidence of GDM. The first trimester is also becoming an important interrogation period for the prediction of many adverse obstetric outcomes including abnormal glucose metabolism. This review outlines the most contemporary evidence on the prediction and non-pharmacological antenatal prevention strategies used for Gestational Diabetes.

Impact of Systemic Inflammation on the Progression of Gestational Diabetes Mellitus

With increasing rates of obesity and new diagnostic criteria for gestational diabetes mellitus (GDM), the overall prevalence of GDM is increasing worldwide. Women with GDM have an increased risk of maternal and fetal complications during pregnancy as well as long-term risks including higher prevalence of type 2 diabetes mellitus and cardiovascular disease. In recent years, the role of immune activation and inflammation in the pathogenesis of GDM has gained increasing attention. This monograph explores the current state of the literature as regards the expression of markers of inflammation in the maternal circulation, placenta, and adipose tissue of women with GDM.

Irisin as an early marker for predicting gestational diabetes mellitus: a prospective study

OBJECTIVE

The objective of this study is to evaluate maternal serum irisin levels in the first and second trimesters of pregnancy in women diagnosed with and without gestational diabetes mellitus (GDM).

METHODS

We performed a prospective, nested case-control study in 258 pregnant women who were enrolled at the time of the first prenatal visit (6-11th weeks of gestation) and followed until delivery. Among the entire population, we selected 20 women who subsequently developed GDM and 30 women with uneventful pregnancies. Blood samples were collected once from each participant at 6-11th weeks of gestation during the fetal viability scan and at 24-28th weeks of gestation during screening for GDM.

RESULTS

In the first trimester, irisin levels were significantly lower in women who later developed GDM (median = 453 ng/mL, range: 257-811 ng/mL) than in controls (median = 721 ng/mL, range: 700-786 ng/mL). In the second trimester, the difference in irisin levels between the GDM group (median = 749 ng/mL; range: 456-910 ng/mL) and controls (median = 757 ng/mL; range: 703-898 ng/mL) was not statistically significant.

CONCLUSIONS

Irisin may be a useful biomarker in early pregnancy to predict the development of GDM.

Could gestational diabetes mellitus be managed through dietary bioactive compounds? Current knowledge and future perspectives

Gestational diabetes mellitus (GDM) is a serious problem growing worldwide that needs to be addressed with urgency in consideration of the resulting severe complications for both mother and fetus. Growing evidence indicates that a healthy diet rich in fruit, vegetables, nuts, extra-virgin olive oil and fish has beneficial effects in both the prevention and management of several human diseases and metabolic disorders. In this review, we discuss the latest data concerning the effects of dietary bioactive compounds such as polyphenols and PUFA on the molecular mechanisms regulating glucose homoeostasis. Several studies, mostly based on in vitro and animal models, indicate that dietary polyphenols, mainly flavonoids, positively modulate the insulin signalling pathway by attenuating hyperglycaemia and insulin resistance, reducing inflammatory adipokines, and modifying microRNA (miRNA) profiles. Very few data about the influence of dietary exposure on GDM outcomes are available, although this approach deserves careful consideration. Further investigation, which includes exploring the ‘omics’ world, is needed to better understand the complex interaction between dietary compounds and GDM.

Adipokine-myokine-hepatokine compartment-system in mothers and children: An explorative study

Objective

Maternal lifestyle during pregnancy has an effect of gestational development and neonatal outcome. Overweight gravidas and gravidas with excessive weight gain have an increased risk of gestational complications and neonatal metabolic disorder. The underlying mechanisms are still under discussion, but the hormonally active fat mass and its biomarkers, adipocytokines, may play a key role by potentially having a direct impact on the metabolic homeostasis of the system in concert with other biomarkers like hepatokines and myokines. Up to now little is known in terms of lifestyle habits and their effect on this complex model on maternal and fetal outcome. Therefore, we aim to investigate the influence of maternal lifestyle clusters during pregnancy on the maternal and fetal biomarkers of compartments, specifically those implying maternal fat and muscle mass, maternal liver and the placenta and who are associated with maternal body composition and birth weight.

Methods

In this exploratory pilot study at least 100 singleton pregnancies and their newborns will be included. The women will undergo assessments of anthropometric measurements, venous blood samples will be drawn and physical activity and nutritional status will be collected through questionnaires. Newborns will undergo assessments of anthropometric measurements, umbilical cord samples will be drawn and birth outcomes will be evaluated. We will measure adipokines, myokines and hepatokines and relate them to maternal lifestyle clusters and fetal outcome.

Conclusion

Our study will be the first to examine the relationship between maternal body composition, birth weight and potential biomarkers based on an innovative compartment model.

Maternal and Fetal Lipid and Adipokine Profiles and Their Association with Obesity

Background. Maternal metabolic changes impact fetal metabolism resulting in a higher risk for developing chronic diseases later in life. The aim of this study was to assess the association between maternal and fetal adipokine and lipid profiles, as well as the influence of maternal weight on this association. Methods. Healthy pregnant women at term who delivered by C-section were enrolled. Maternal and fetal glucose, lipid profile, adiponectin, leptin, and resistin levels were analyzed by obesity and maternal weight gain. Statistics included descriptives, correlations, and mean differences (SPSS v20.0). Results. Adiponectin and resistin concentrations were higher in fetal blood, while leptin was lower (p < 0.05). A significant inverse association between maternal resistin and fetal LDL-cholesterol (LDL-C) (r = -0.327; p = 0.022) was observed. A positive correlation was found between maternal and fetal resistin (r = 0.358; p = 0.013). Women with excessive weight gain had higher leptin levels and their fetuses showed higher LDL-C levels (p < 0.05). Conclusions. Maternal resistin showed an inverse association with fetal LDL-C, suggesting that maternal adiposity status may play an active role in the regulation of fetal lipid profile and consequently, in fetal programming. Excessive maternal weight gain during pregnancy may exert an effect over metabolic mediators in both mother and newborn.

The endocrine function of human placenta: an overview

During pregnancy, several tightly coordinated and regulated processes take place to enable proper fetal development and gestational success. The formation and development of the placenta is one of these critical pregnancy events. This organ plays essential roles during gestation, including fetal nourishment, support and protection, gas exchange and production of several hormones and other mediators. Placental hormones are mainly secreted by the syncytiotrophoblast, in a highly and tightly regulated way. These hormones are important for pregnancy establishment and maintenance, exerting autocrine and paracrine effects that regulate decidualization, placental development, angiogenesis, endometrial receptivity, embryo implantation, immunotolerance and fetal development. In addition, because they are released into maternal circulation, the profile of their blood levels throughout pregnancy has been the target of intense research towards finding potential robust and reliable biomarkers to predict and diagnose pregnancy-associated complications. In fact, altered levels of these hormones have been associated with some pathologies, such as chromosomal anomalies or pre-eclampsia. This review proposes to revise and update the main pregnancy-related hormones, addressing their major characteristics, molecular targets, function throughout pregnancy, regulators of their expression and their potential clinical interest.

Circulating Betatrophin Is Strongly Increased in Pregnancy and Gestational Diabetes Mellitus

Aims/hypothesis

Betatrophin has recently been introduced as a novel hormone and promotor of beta cell proliferation and improved glucose tolerance in mouse models of insulin resistance. In obese and diabetic humans altered levels were reported and a role in pathophysiology of metabolic diseases was therefore hypothesized. However its release and regulation in women with gestational diabetes mellitus (GDM), as well as its associations with markers of obesity, glucose and lipid metabolism during pregnancy still remain unclear.

Methods

Circulating betatrophin was quantified in 21 women with GDM and 19 pregnant body mass index-matched women with normal glucose tolerance (NGT) as well as 10 healthy age-matched non-pregnant women by enzyme-linked immunosorbent assay. Additionally we performed radioimmunassay (RIA) to confirm the results.

Results

Betatrophin concentrations measured by ELISA were significantly higher in GDM than in NGT (29.3±4.4 ng/ml vs. 18.1±8.7 ng/ml, p<0.001) which was confirmed by RIA. Betatrophin did not correlate with BMI or insulin resistance but showed a weak association with leptin levels in pregnancy and negative relationship with fasting C-peptide levels in all women. Moreover it correlated significantly with lipid parameters including triglycerides and total cholesterol in pregnancy, as well as estrogen, progesteron and birth weight.

Conclusions/interpretation

Circulating betatrophin concentrations are dramatically increased in pregnancy and are significantly higher in GDM versus pregnant NGT. In the light of the previously reported role in lipid metabolism, betatrophin may represent a novel endocrine regulator of lipid alterations in pregnancy. However additional studies are needed to elucidate whether hormonal factors, such as estrogen, control the production of betatrophin and if targeting betatrophin could hold promise in the fight against metabolic disease.

Inflammatory and Other Biomarkers: Role in Pathophysiology and Prediction of Gestational Diabetes Mellitus

Understanding pathophysiology and identifying mothers at risk of major pregnancy complications is vital to effective prevention and optimal management. However, in current antenatal care, understanding of pathophysiology of complications is limited. In gestational diabetes mellitus (GDM), risk prediction is mostly based on maternal history and clinical risk factors and may not optimally identify high risk pregnancies. Hence, universal screening is widely recommended. Here, we will explore the literature on GDM and biomarkers including inflammatory markers, adipokines, endothelial function and lipids to advance understanding of pathophysiology and explore risk prediction, with a goal to guide prevention and treatment of GDM.