Is sex hormone-binding globulin associated with glucose tolerance?

Hormonal regulation in diabetes: Special emphasis on sex hormones and metabolic traits

Diabetes constitutes a significant global public health challenge that is rapidly reaching epidemic proportions. Among the non-communicable diseases, the incidence of diabetes is rising at an alarming rate. The International Diabetes Federation has documented a 9.09% prevalence of diabetes among individuals aged between 20 and 79 years. The interplay of gonadal hormones and gender differences is critical in regulating insulin sensitivity and glucose tolerance, and this dynamic is particularly crucial because of the escalating incidence of diabetes. Variations in insulin sensitivity are observed across genders, levels of adiposity, and age groups. Both estrogen and testosterone are seen to influence glucose metabolism and insulin sensitivity. This chapter surveys the present knowledge of sex differences, sex hormones, and chromosomes on insulin imbalance and diabetes development. It further highlights the influence of metabolic traits in diabetes and changes in sex hormones during diabetic pregnancy. Notably, even stressful lifestyles have been acknowledged to induce hormonal imbalances. Furthermore, it discusses the potential of hormonal therapy to help stabilize sex hormones in diabetic individuals and focuses on the most recent research investigating the correlation between sex hormones and diabetes.

Steroids, steroid associated substances and gestational diabetes mellitus

As gestational diabetes mellitus (GDM) is both a frequent and serious complication, steroid levels in pregnancy are extremely elevated and their role in pregnancy is crucial, this review focuses on the role of steroids and related substances in the GDM pathophysiology. Low SHBG levels are associated with insulin resistance and hyperinsulinemia, while also predicting a predisposition to GDM. Other relevant agents are placental hormones such as kisspeptin and CRH, playing also an important role beyond pregnancy, but which are synthesized here in smaller amounts in the hypothalamus. These hormones affect both the course of pregnancy as well as the synthesis of pregnancy steroids and may also be involved in the GDM pathophysiology. Steroids, whose biosynthesis is mainly provided by the fetal adrenal glands, placenta, maternal adrenal glands, and both maternal and fetal livers, are also synthesized in limited amounts directly in the pancreas and may influence the development of GDM. These substances involve the sulfated Δ5 steroids primarily acting via modulating different ion channels and influencing the development of GDM in different directions, mostly diabetogenic progesterone and predominantly anti-diabetic estradiol acting both in genomic and non-genomic way, androgens associated with IR and hyperinsulinemia, neuroactive steroids affecting the pituitary functioning, and cortisol whose production is stimulated by CRH but which suppresses its pro-inflammatory effects. Due to the complex actions of steroids, studies assessing their predominant effect and studies assessing their predictive values for estimating predisposition to GDM are needed.

Early Identification of the Maternal, Placental and Fetal Dialog in Gestational Diabetes and Its Prevention

Gestational diabetes mellitus (GDM) complicates between 5 and 12% of pregnancies, with associated maternal, fetal, and neonatal complications. The ideal screening and diagnostic criteria to diagnose and treat GDM have not been established and, currently, diagnostic use with an oral glucose tolerance test occurs late in pregnancy and produces poor reproducibility. Therefore, in recent years, significant research has been undertaken to identify a first-trimester biomarker that can predict GDM later in pregnancy, enable early intervention, and reduce GDM-related adverse pregnancy outcomes. Possible biomarkers include glycemic markers (fasting glucose and hemoglobin A1c), adipocyte-derived markers (adiponectin and leptin), pregnancy-related markers (pregnancy-associated plasma protein-A and the placental growth factor), inflammatory markers (C-reactive protein and tumor necrosis factor-α), insulin resistance markers (sex hormone-binding globulin), and others. This review summarizes current data on first-trimester biomarkers, the advantages, and the limitations. Large multi-ethnic clinical trials and cost-effectiveness analyses are needed not only to build effective prediction models but also to validate their clinical use.

Emerging Protein Biomarkers for the Diagnosis or Prediction of Gestational Diabetes-A Scoping Review

Introduction: Gestational diabetes (GDM), defined as hyperglycemia with onset or initial recognition during pregnancy, has a rising prevalence paralleling the rise in type 2 diabetes (T2DM) and obesity. GDM is associated with short-term and long-term consequences for both mother and child. Therefore, it is crucial we efficiently identify all cases and initiate early treatment, reducing fetal exposure to hyperglycemia and reducing GDM-related adverse pregnancy outcomes. For this reason, GDM screening is recommended as part of routine pregnancy care. The current screening method, the oral glucose tolerance test (OGTT), is a lengthy, cumbersome and inconvenient test with poor reproducibility. Newer biomarkers that do not necessitate a fasting sample are needed for the prompt diagnosis of GDM. The aim of this scoping review is to highlight and describe emerging protein biomarkers that fulfill these requirements for the diagnosis of GDM. Materials and Methods: This scoping review was conducted according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines for scoping reviews using Cochrane Central Register of Controlled Trials (CENTRAL), the Cumulative Index to Nursing & Allied Health Literature (CINAHL), PubMed, Embase and Web of Science with a double screening and extraction process. The search included all articles published in the literature to July 2020. Results: Of the 3519 original database citations identified, 385 were eligible for full-text review. Of these, 332 (86.2%) were included in the scoping review providing a total of 589 biomarkers studied in relation to GDM diagnosis. Given the high number of biomarkers identified, three post hoc criteria were introduced to reduce the items set for discussion: we chose only protein biomarkers with at least five citations in the articles identified by our search and published in the years 2017-2020. When applied, these criteria identified a total of 15 biomarkers, which went forward for review and discussion. Conclusions: This review details protein biomarkers that have been studied to find a suitable test for GDM diagnosis with the potential to replace the OGTT used in current GDM screening protocols. Ongoing research efforts will continue to identify more accurate and practical biomarkers to take GDM screening and diagnosis into the 21st century.

Association of sex hormone binding globulin with gestational age and parity in gestational diabetes mellitus

Objective: Recent research on sex hormone binding globulin (SHBG) has emphasized its role in the prediction of gestational diabetes mellitus (GDM) development. SHBG is associated with glucose tolerance status, and its level is regulated by prenatal and perinatal factors during pregnancy. This study aimed to determine the levels of SHBG in pregnant women with normal glucose tolerance and those with GDM in association with parity and gestational age (weeks).Materials and methods: This cross-sectional study enrolled 218 pregnant women (165 controls and 53 women with GDM). Serum SHBG levels were analyzed using enzyme-linked immunosorbent assay. The association of SHBG with gestational age was assessed using multivariate regression analysis after adjustment for GDM-related risk factors.Results: Parity sub-group analyses indicated the presence of significant differences in the SHBG levels between nulliparous women in the GDM and control groups (p = .04). Moreover, in the GDM group, SHBG was significantly associated with gestational age beyond the risk factors of GDM.Conclusion: This study demonstrated a strong association between SHBG and gestational age in women with GDM. Our findings suggest that parity and gestational age should be considered in the analysis of SHBG as a marker for GDM diagnosis.

Sex Hormone-binding Globulin, Cardiometabolic Biomarkers, and Gestational Diabetes: A Longitudinal Study and Meta-analysis

Objective

This study investigated the prospective associations of circulating levels of sex hormone-binding globulin (SHBG) levels with cardiometabolic biomarkers and risk of gestational diabetes (GDM) during pregnancy. It also examines the longitudinal trajectory of SHBG in women with and without GDM.

Methods

We conducted a nested case-control study of 107 incident GDM cases and 214 matched controls within the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies-Singleton Cohort. The cohort enrolled non-obese and obese women aged 18-40 years with a singleton pregnancy between 8 and 13 weeks of gestation from 2009 to 2013. GDM was ascertained via medical records review. Blood samples were drawn four times at gestational weeks 10-14, 15-26, 23-31, and 33-39. The prospective associations between SHBG levels and cardiometabolic biomarkers were examined using the Spearman partial correlation among the controls. The longitudinal trajectories of SHBG levels were examined among the cases and the controls. Meta-analysis of prospective studies were performed to examine the association between SHBG levels and GDM risk.

Results

SHBG levels at gestational weeks 10-14 were significantly inversely associated with fasting insulin (r = -0.17, P = 0.01) and insulin resistance as measured by HOMA-IR (r = -0.17, P = 0.01) at gestational week 15-26. SHBG at gestational weeks 10-14 and 15-26 was lower in cases than controls (mean ± standard deviation: (204.0 ± 97.6) vs. (220.9 ± 102.5) nmol/L, P = 0.16 and (305.6 ± 124.3) vs. (322.7 ± 105.1) nmol/L, P = 0.14, respectively), yet the differences were not significant. In the meta-analysis, SHBG was 41.5 nmol/L (95% confidence interval: 23.9, 59.1, P < 0.01) significantly lower among women with GDM than without, and each 50 nmol/L increase in SHBG was significantly associated with an odds ratio of 0.85 (95% confidence interval: 0.76-0.95, P = 0.01) for GDM.

Conclusion

Lower SHBG levels in early pregnancy were prospectively associated with higher high insulin levels and insulin resistance in mid-pregnancy and subsequent risk of GDM, independent of adiposity. SHBG may serve as a marker for the identification of high-risk pregnancies during early pregnancy.

Sex hormone binding globulin for prediction of gestational diabetes mellitus in pre-conception and pregnancy: A systematic review

AIM

The purpose of the present study was to assess the relationship of sex hormone binding globulin (SHBG) and gestational diabetes mellitus (GDM).

METHODS

The Cochrane Library, Medline, ScienceDirect, and Web of Science were searched for studies published from the inception of the databases up to February 2019. Our inclusion criteria were published observational full-text articles. All data were analyzed using Review Manager 5.3. Of 208 papers reviewed, 26 studies (n = 6668) were considered for meta-analysis.

RESULTS

The SHBG level was significantly lower in women with GDM compared to healthy women (MD = -11.86; 95% CI: [-13.02, -10.71]). Also, SHBG in women with PCOS and GDM and obesity was significantly lower than women with PCOS without GDM (MD = -38.14; 95% CI: [-56.79, -19.48]) and normal weight women (MD: -58.96; 95% CI: [-79.32, -38.59]). SHBG in the second trimester was lower than that in the first trimester and pre-conception.

CONCLUSIONS

This systematic review showed that the level of SHBG is significantly lower in GDM pregnant women than that in healthy women. The results of this systematic review about the relationship of GDM and SHBG and suggestion to assess this marker in early pregnancy should be considered with caution.

SHBG expression is correlated with PI3K/AKT pathway activity in a cellular model of human insulin resistance

Decreased sex hormone-binding globulin (SHBG) expression is an independent risk factor for gestational diabetes mellitus(GDM).However, the mechanisms that link low SHBG expression and insulin resistance in GDM is unclear. In this study, we investigated the placenta SHBG in the PI3K/AKT pathway to reveal the mechanism that links decreased SHBG to insulin resistance. A insulin resistance cells model was established by the method of insulin stimulation. Two groups were set up, HTR8/Svneo cells and insulin-resistance cells of HTR8/SVneo. The expression of SHBG and PI3K/AKT associated factors were detected using real-time PCR and western blotting and their correlations were analyzed. The results showed that SHBG protein and mRNA levels in insulin resistance cells were both significantly lower. Along with decreased SHBG expression, the mRNA and protein levels of IRS-1, IRS-2, PI3Kp85α and GLUT-3, GLUT-4 decreased significantly. However, the expression of GLUT-1 increased significantly. Pearson correlation analysis showed that SHBG mRNA expression was positively correlated with IRS-1, IRS-2 and PI3Kp85α mRNA levels. According to the results, low SHBG expression not only participates in the development of local insulin resistance, but may also play an important role in PI3K/AKT pathway-mediated systemic insulin resistance and gestational diabetes.

Prediction of gestational diabetes mellitus at first trimester in low-risk pregnancies

OBJECTIVE

We aimed to assess the relationship among the sex hormone-binding globulin (SHBG), homeostasis model assessment (HOMA), glycosylated hemoglobin (HbA1c), and cholesterol panel values to predict subsequent gestational diabetes mellitus (GDM) in low-risk pregnancies.

MATERIALS AND METHODS

Thirty-eight pregnant women with GDM and 295 low-risk pregnant women without GDM were included in this study. Maternal blood samples were obtained during the first trimester examination to determine the SHBG, HbA1c, fasting blood glucose, insulin, thyroid stimulating hormone (TSH), free thyroxine, total cholesterol, triglycerides (TG), high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDL-C) levels. The variables that exhibited statistically significant differences between the groups and independent predictors for GDM were examined using logistic regression analysis. The risk of developing GDM, according to cutoff values, was determined using receiver operating characteristic (ROC) curve analysis.

RESULTS

The SHBG, HOMA, LDL, and TG levels were found to be the significant independent markers for GDM [adjusted odds ratio (OR) = 0.991; 95% confidence interval (CI), 0.986-995; OR = 1.56; 95% CI, 1.24-1.98; OR = 1.02; 95% CI, 1.01-1.04; and OR = 1.01; 95% CI, 1.00-1.02, respectively]. The HbA1c, body mass index, and mean arterial pressure values were nonindependent predictors of GDM. The areas under the ROC curve used to determine the predictive accuracy of SHBG, HOMA, TG, and LDL-C for development of GDM were 0.73, 0.75, 0.70, and 0.72, respectively. For a false positive rate of 5% for the prediction of GDM, the values of the sensitivities were 21.1, 26.3, 21.1, and 18.4%, respectively.

CONCLUSION

The HOMA, SHBG, TG, and LDL-C levels are independent predictors for subsequent development of GDM in low-risk pregnancies, but they exhibit low sensitivity.

Expression and correlation of sex hormone-binding globulin and insulin signal transduction and glucose transporter proteins in gestational diabetes mellitus placental tissue

OBJECTIVE

The aim of the present study was to investigate the probable pathogenesis of gestational diabetes mellitus (GDM) by analyzing the correlation between sex hormone-binding globulin (SHBG) secreted by the placenta during pregnancy and insulin signaling components and glucose transporter proteins (GLUTs) in the placental tissue.

DESIGN AND METHODS

Placental tissue was collected from full-term and non-obese [body mass index <25kg/m(2)] pregnant women; 10 diagnosed with GDM and 10 with normal pregnancy. We used real-time polymerase chain reaction (PCR), immunohistochemistry and western blotting to detect expression of protein and mRNA of SHBG and insulin signaling components and GLUTs in placental tissue.

RESULTS

In the placental tissue of non-obese women, there was a decrease in expression of SHBG protein and mRNA, with a concurrent decrease in expression of GLUT-4 protein and mRNA in women with GDM compared with normal controls. There was a decrease in GLUT-3 and insulin receptor substrate (IRS)-1 protein expression and lower IRS-2 mRNA expression was also observed in GDM placental tissue. Linear correlation analyses showed a positive correlation between SHBG and IRS-2 mRNA (P=0.038, R(2)=0.2178, y=0.249x+1.4208); positive correlation between SHBG and phosphatidylinositol 3-kinase (PI3K) p85α mRNA (P=0.035, R(2)=0.224, y=0.3506x+0.7433); positive correlation between SHBG and GLUT-4 mRNA (P=0.000, R(2)=0.5174, y=1.3822+1.7811x); positive correlation between IRS-2 and GLUT-4 mRNA (P=0.002, R(2)=0.4064, y=-0.8272+2.9592x); negative correlation between IRS-1 and PI3K p85α mRNA (P=0.005, R(2)=0.366, y=2.4492-0.1929x); negative correlation between IRS-1 and GLUT-3 mRNA (P=0.027, R(2)=0.243, y=0.9254-0.0714x); and positive correlation between IRS-2 and GLUT-1 mRNA (P=0.004, R(2)=0.3794, y=0.0225+0.6298x).

CONCLUSION

The results confirm that defective receptors for insulin signal transduction and GLUT proteins are present in GDM placental tissue. Decreasing expression of SHBG may participate in regulation of insulin signaling, leading to a concomitant decrease in expression of relevant insulin signaling components in placental tissue, implying insulin resistance and eventual development of GDM.

SHBG in GDM maternal serum, placental tissues and umbilical cord serum expression changes and its significance

AIMS

To compare the expression of sex hormone binding globulin (SHBG) in normal placental tissues and serum with placental tissues from patients with gestational diabetes mellitus (GDM) and to deduce the mechanism affecting placental SHBG in GDM.

METHODS

Enzyme-linked immunosorbent assay (ELISA) method were used to detect SHBG levels changes in normal and GDM maternal serum, umbilical cord serum and placental. We measured SHBG mRNA and protein using reverse-transcription polymerase chain reaction, and Western blotting, respectively, in normal and GDM placental tissues.

RESULTS

In maternal serum, compared with the control group, GDM group: glucose, insulin increased, SHBG decreased. In the placenta, compared with the control group, GDM group: SHBG, SHBG mRNA and SHBG protein decreased. There is no correlation between placenta SHBG and maternal serum SHBG respectively in control and GDM group, but in GDM group maternal serum insulin and placenta SHBG are linear correlation.

CONCLUSIONS

GDM serum and placental SHBG levels are reduced, hyperinsulinemia may lead to a reduction of SHBG in circulating blood, but also damage the placenta cells which led to placental synthesis and secretion of SHBG decrease.

Expression changes of sex hormone binding globulin in GDM placental tissues

OBJECTIVE

To compare the expression of sex hormone binding globulin (SHBG) in normal placental tissues with placental tissues from patients with gestational diabetes mellitus (GDM) and to deduce the mechanism affecting placental SHBG in GDM.

METHODS

We detected SHBG localization and measured SHBG mRNA and protein using immunohistochemistry, reverse-transcription polymerase chain reaction, and Western blotting, respectively, in normal and GDM placental tissues. The distribution of SHBG in placental cells was examined using immune electron microscopy.

RESULTS

Compared to controls, placental tissues from patients in the GDM group displayed disordered cell surface microvilli that were decreased in quantity, swollen, and had narrowed and broken gap junctions. Intracellular abnormalities included expanded rough endoplasmic reticula, swollen mitochondria, and irregular nuclear morphologies with non-uniform chromatin. SHBG localized primarily to trophoblast cell membranes and cytoplasm. SHBG was strongly expressed on the microvilli side and weakly expressed on the basement membrane with uneven staining. SHBG also was expressed in villous stromal cells and vascular endothelial cells. Compared to the controls, placental tissues from the GDM group displayed significantly decreased immunostaining rates for SHBG, as well as significantly lower levels of SHBG mRNA and protein expression (P<0.05).

CONCLUSION

SHBG was detected in placental trophoblast cells from patients with GDM, and the synthesis and secretion of SHBG were reduced when trophoblast cells were irregular. A decrease in SHBG could affect placental function or aggravate GDM. Our results suggest that placental SHBG plays an important role in the pathogenesis of GDM.

Decreased variation of inflammatory markers in gestational diabetes

BACKGROUND

Gestational diabetes is a prediabetic state. Sub-clinical inflammation may play a role in the transition from gestational diabetes to type 2 diabetes; the role of the autonomic nervous system as a mediating system has been raised. We aimed to study the association of the sympathetic nervous system and sub-clinical inflammation in women with gestational diabetes.

METHODS

We studied 41 Caucasian women with gestational diabetes and 22 healthy pregnant and 14 non-pregnant controls. We assayed plasma noradrenaline, insulin, C-reactive protein, interleukin-6, insulin growth factor-1, serum amyloid A, steroid hormone-binding globulin, α-1 acid glycoprotein and cortisol at 2400, 0400 and 0700 h.

RESULTS

No differences existed in the concentrations of inflammatory markers between gestational diabetes and normal pregnancy but women with gestational diabetes showed loss of variation in C-reactive protein and serum amyloid A. Levels of hormone-binding globulin were lower in hypertensive compared with normotensive women with gestational diabetes at all time points and lowest at midnight when α-1 acid glycoprotein levels were higher in hypertensive women.

CONCLUSIONS

Gestational diabetes is associated with loss of natural variation of C-reactive protein and serum amyloid A, suggesting altered modulation of inflammation. Hypertension in gestational diabetes seems not to be associated with higher levels of inflammatory markers other than α-1 acid glycoprotein.

The change in sex hormone binding globulin and the influence by gestational diabetes mellitus in fetal period

OBJECTIVE

To investigate the influence of gestational diabetes mellitus (GDM) on the change of SHBG in fetus.

METHOD

Forty-eight pregnant women with GDM and 86 women with normal pregnancy were included in the study. The following were measured in the serums of pregnant women, amniotic fluids, and umbilical cord serums: glucose, insulin, peptide-C, SHBG, and sex hormones.

RESULTS

SHBGs in pregnant women's serums were, when compared with the control group: in male fetuses 308.06 +/- 55.64 vs. 445.21 +/- 50.07 (p < 0.01) and in female fetuses 312.38 +/- 56.61 vs. 451.05 +/- 52.87 (p < 0.01). When comparing the levels of SHBGs in amniotic fluids, inclusive of the control group, the following were in male fetuses 8.35 +/- 1.07 vs. 8.41 +/- 1.09 (p = NS) and in female fetuses 8.31 +/- 0.97 vs. 8.39 +/- 0.94 (p = NS). For the levels of SHBGs in umbilical cord serums and comparison to the control group were: in male fetuses 41.44 +/- 8.83 vs. 40.24 +/- 7.50 (p = NS) and in female fetuses 39.93 +/- 7.04 vs. 39.69 +/- 7.16 (p = NS). The concentration of SHBG in amniotic fluid had no significant relationship to glucose, dehydroepiandrosterone (DHEAS), estradiol, and total and free testosterone, but had an extremely negatively correlated to insulin and peptide-C (p < 0.01) in GDM group.

CONCLUSION

Although the concentration of SHBG does not change in fetus when pregnant woman is complicated with GDM, it is already influenced by the fetal regulation on hyperinsulinemia.