Plasminogen activator inhibitor 1 gene polymorphism and gestational diabetes mellitus

Update on the genetic and epigenetic etiology of gestational diabetes mellitus: a review

Background

Many studies have been conducted on the genetic and epigenetic etiology of gestational diabetes mellitus (GDM) in the last two decades because of the disease’s increasing prevalence and role in global diabetes mellitus (DM) explosion. An update on the genetic and epigenetic etiology of GDM then becomes imperative to better understand and stem the rising incidence of the disease. This review, therefore, articulated GDM candidate genes and their pathophysiology for the awareness of stakeholders.

Main body (genetic and epigenetic etiology, GDM)

The search discovered 83 GDM candidate genes, of which TCF7L2, MTNR1B, CDKAL1, IRS1, and KCNQ1 are the most prevalent. Certain polymorphisms of these genes can modulate beta-cell dysfunction, adiposity, obesity, and insulin resistance through several mechanisms. Environmental triggers such as diets, pollutants, and microbes may also cause epigenetic changes in these genes, resulting in a loss of insulin-boosting and glucose metabolism functions. Early detection and adequate management may resolve the condition after delivery; otherwise, it will progress to maternal type 2 diabetes mellitus (T2DM) and fetal configuration to future obesity and DM. This shows that GDM is a strong risk factor for T2DM and, in rare cases, type 1 diabetes mellitus (T1DM) and maturity-onset diabetes of the young (MODY). This further shows that GDM significantly contributes to the rising incidence and burden of DM worldwide and its prevention may reverse the trend.

Conclusion

Mutations and epigenetic changes in certain genes are strong risk factors for GDM. For affected individuals with such etiologies, medical practitioners should formulate drugs and treatment procedures that target these genes and their pathophysiology.

Circulating Levels of Bone and Inflammatory Markers in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) can cause short- and long-term complications to the mother and fetus. While the precise mechanisms in preserving glucose balance in a healthy pregnancy are unknown, various growth factors and hormones have been implicated or associated with GDM risk in humans or rodents, including prolactin, tumor necrosis factor alpha (TNFα), osteoprotegerin (OPG), hepatocyte growth factor (HGF), and receptor activator of nuclear factor-kappa B ligand (RANKL). We aimed to evaluate the relationship of these and other protein markers in women with GDM. In this cross-sectional study, blood samples were collected from pregnant women with GDM and with normal glucose tolerance (NGT) at the 24- to 32-week obstetrical visit, during the 1-h oral glucose challenge test or 3-h oral glucose tolerance test. Blood plasma was analyzed for RANKL, OPG, prolactin, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), HGF, plasminogen activator inhibitor type 1 (PAI-1), and TNFα. Forty-six women with NGT and 47 women with GDM were included (mean ± standard deviation maternal age 31.6 ± 5.7, mean ± standard deviation gestational age 28.1 ± 2.2 weeks). Groups were similar in terms of age, body mass index, gestational age, and race/ethnicity. Serum levels of OPG, prolactin, TRAIL, HGF, PAI-1, and TNFα were similar in both groups. RANKL was lower in GDM subjects (p = 0.019). Contrary to previous reports in the literature, we found a lower serum RANKL level in women with GDM. Further investigation is needed to determine whether there are suitable serum markers for diagnosing GDM or determining prognosis or severity.

Gestational diabetes from A to Z

Gestational diabetes mellitus (GDM) is defined as any degree of hyperglycaemia that is recognized for the first time during pregnancy. This definition includes cases of undiagnosed type 2 diabetes mellitus (T2DM) identified early in pregnancy and true GDM which develops later. GDM constitutes a greater impact on diabetes epidemic as it carries a major risk of developing T2DM to the mother and foetus later in life. In addition, GDM has also been linked with cardiometabolic risk factors such as lipid abnormalities, hypertensive disorders and hyperinsulinemia. These might result in later development of cardiovascular disease and metabolic syndrome. The understanding of the different risk factors, the pathophysiological mechanisms and the genetic factors of GDM, will help us to identify the women at risk, to develop effective preventive measures and to provide adequate management of the disease. Clinical trials have shown that T2DM can be prevented in women with prior GDM, by intensive lifestyle modification and by using pioglitazone and metformin. However, a matter of controversy surrounding both screening and management of GDM continues to emerge, despite several recent well-designed clinical trials tackling these issues. The aim of this manuscript is to critically review GDM in a detailed and comprehensive manner, in order to provide a scientific analysis and updated write-up of different related aspects.

Role of Plasminogen Activator Inhibitor Type 1 in Pathologies of Female Reproductive Diseases

Normal pregnancy is a state of hypercoagulability with diminishing fibrinolytic activity, which is mainly caused by an increase of plasminogen activator inhibitor type 1 (PAI-1). PAI-1 is the main inhibitor of plasminogen activators, including tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). In human placentas, PAI-1 is expressed in extravillous interstitial trophoblasts and vascular trophoblasts. During implantation and placentation, PAI-1 is responsible for inhibiting extra cellular matrix (ECM) degradation, thereby causing an inhibition of trophoblasts invasion. In the present study, we have reviewed the literature of various reproductive diseases where PAI-1 plays a role. PAI-1 levels are increased in patients with recurrent pregnancy losses (RPL), preeclampsia, intrauterine growth restriction (IUGR), gestational diabetes mellitus (GDM) in the previous pregnancy, endometriosis and polycystic ovary syndrome (PCOS). In general, an increased expression of PAI-1 in the blood is associated with an increased risk for infertility and a worse pregnancy outcome. GDM and PCOS are related to the genetic role of the 4G/5G polymorphism of PAI-1. This review provides an overview of the current knowledge of the role of PAI-1 in reproductive diseases. PAI-1 represents a promising monitoring biomarker for reproductive diseases and may be a treatment target in the near future.

Gestational diabetes: risk factors and recent advances in its genetics and treatment

The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study of over 23000 diabetes-free pregnancies has shown that at a population level an unequivocal linear relationship exists between maternal glucose concentrations around the beginning of the third trimester of pregnancy and the risk of their baby being born above the ninetieth centile for weight. With the rising incidence of gestational diabetes (GDM) across the developed world, largely paralleling the increased prevalence of obesity, there has been a sharp increase in the risk of pregnancy complications developing related to the birth of macrosomic babies. The associated additional long-term complications of GDM pregnancies means that in the future there is likely to be a large increase in the incidence of type 2 diabetes and associated conditions in both the mothers and their affected offspring. The present review seeks to highlight recent advances and remaining gaps in knowledge about GDM in terms of its genetics (where some of the recently discovered polymorphic risk factors for type 2 diabetes have also proved to be risk factors for GDM) and its treatment by diet, exercise and drugs.

Maternal and paternal race/ethnicity are both associated with gestational diabetes

OBJECTIVE

The objective of the study was to examine the rates of gestational diabetes mellitus (GDM) associated with both maternal and paternal race/ethnicity.

STUDY DESIGN

This was a retrospective cohort study of all women delivered within a managed care network. Rates of GDM were calculated for maternal, paternal, and combined race/ethnicity.

RESULTS

Among the 139,848 women with identified race/ethnicity, Asians had the highest rate (P < .001) of GDM (6.8%) as compared with whites (3.4%), African Americans (3.2%), and Hispanics (4.9%). When examining race/ethnicity controlling for potential confounders, we found that the rates of GDM were higher among Asian (adjusted odds ratio [aOR], 1.5; 95% confidence interval [CI], 1.4-1.6) and Hispanic (aOR, 1.2; 95% CI, 1.1-1.4) women as well as Asian (aOR, 1.4; 95% CI, 1.3-1.5) and Hispanic (aOR, 1.3; 95% CI, 1.2-1.4) men as compared with their white counterparts.

CONCLUSION

We found that rates of GDM are affected by both maternal and paternal race/ethnicity. In both Asians and Hispanics, maternal and paternal race are equally associated with an increase in GDM. These differences may inform further investigation of the pathophysiology of GDM.

Type 2 diabetes-associated genetic variants discovered in the recent genome-wide association studies are related to gestational diabetes mellitus in the Korean population

AIMS/HYPOTHESIS

New genetic variants associated with susceptibility to type 2 diabetes mellitus have been discovered in recent genome-wide association (GWA) studies. The aim of the present study was to examine the association between these diabetogenic variants and gestational diabetes mellitus (GDM).

METHODS

The study included 869 Korean women with GDM and 345 female and 287 male Korean non-diabetic controls. We genotyped the single nucleotide polymorphisms (SNPs) rs7756992 and rs7754840 in CDKAL1; rs564398, rs1333040, rs10757278 and rs10811661 in the CDKN2A-CDKN2B region; rs8050136 in FTO; rs1111875, rs5015480 and rs7923837 in HHEX; rs4402960 in IGF2BP2; and rs13266634 in SLC30A8. In addition, rs7903146 and rs12255372 in TCF7L2; rs5215 and rs5219 in KCNJ11; and rs3856806 and rs1801282 in PPARG were genotyped. The genotype frequencies in the GDM patients were compared with those in the non-diabetic controls.

RESULTS

Compared with controls (men and women combined), GDM was associated with rs7756992 and rs7754840 (OR 1.55, 95% CI 1.34-1.79, p = 4.17 x 10(-9)) in CDKAL1; rs10811661 (OR 1.49, 95% CI 1.29-1.72, p = 1.05 x 10(-7)) in the CDKN2A-CDKN2B region; rs1111875 (OR 1.27, 95% CI 1.09-1.49, p = 0.003), rs5015480, and rs7923837 in HHEX; rs4402960 (OR 1.18, 95% CI 1.01-1.38, p = 0.03) in IGF2BP2; rs13266634 (OR 1.24, 95% CI 1.07-1.43, p = 0.005) in SLC30A8; and rs7903146 (OR 1.58, 95% CI 1.03-2.43, p = 0.038) in TCF7L2. The risk alleles of the SNPs rs7756992 and rs7754840 in CDKAL1; rs10811661 in the CDKN2A-CDKN2B region; and rs1111875, rs5015480 and rs7923837 in HHEX were associated with significant decreases in the insulin AUC during a 100 g OGTT performed at the time of diagnosis of GDM.

CONCLUSIONS/INTERPRETATION

Some of the type 2 diabetes-associated genetic variants that were discovered in the recent GWA studies are also associated with GDM in Koreans.

The genetics of gestational diabetes mellitus: evidence for relationship with type 2 diabetes mellitus

Gestational diabetes is a major public health problem because of its prevalence, its associated complications during pregnancy, and its increased risk for type 2 diabetes later in life. Insulin resistance is one of many physiological changes occurring during pregnancy, and when insulin resistance is accompanied by pancreatic beta-cell insufficiency, gestational diabetes may develop. Several lines of evidence suggest that gestational diabetes shares a common etiology with type 2 diabetes and support the hypothesis that gestational diabetes serves as a window to reveal a predisposition to type 2 diabetes. Pregnancy is an environmental stressor that may catalyze the progression to a diabetic state in genetically predisposed women; therefore, identification of these women during pregnancy could decrease the occurrence of type 2 diabetes through targeted prevention. This review presents an overview of the genetics of gestational diabetes, focusing on human association studies with candidate genes common to both type 2 diabetes and gestational diabetes.

An observational study of reduction of insulin resistance and prevention of development of type 2 diabetes mellitus in women with polycystic ovary syndrome treated with metformin and diet

Our first specific aim in an observational study of 431 nondiabetic women with polycystic ovary syndrome (PCOS), aged >or=20 years and with >or=11 months follow-up on metformin diet, was to prospectively assess relationships between pretreatment glucose and insulin resistance (IR) and the development of type 2 diabetes mellitus (T2DM) or gestational diabetes (GD). Our second specific aim was to determine whether development of T2DM and GD was independently associated with lesser reduction of IR on metformin diet when compared with women who remained free of T2DM and GD. Women with body mass index <25 kg/m(2) and those with body mass index >or=25 kg/m(2) were, respectively, instructed in a 2000- or 1500-cal/d, high-protein (26% of calories), low-carbohydrate (44%) diet, with 30% of calories as fat and a polyunsaturate-saturate ratio of 2:1. Three groups of women with PCOS were categorized: (a) 17 with no previous GD, who developed T2DM on metformin diet (mean +/- SD follow-up, 49 +/- 33 months), (b) 401 with no previous GD and free of T2DM on metformin diet (follow-up, 38 +/- 25 months), and (c) 13 with either previous GD or GD on metformin diet (follow-up, 38 +/- 25 months). On metformin diet, women who developed T2DM vs those who remained free of T2DM had higher pretreatment glucose (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.03-1.16; P = .003) and homeostasis model assessment of insulin resistance (HOMA-IR) (OR, 1.22; 95% CI, 1.04-1.42; P = .01), and less reduction of HOMA-IR (OR, 0.82; 95% CI, 0.72-0.92; P = .0008). On metformin diet, women either with previous GD or who developed GD vs those who remained free of T2DM had less reduction of HOMA-IR (OR, 0.88; 95% CI, 0.78-0.99; P = .03). By repeated-measures analysis, on metformin diet, women who did not develop T2DM had reduction in HOMA-IR (P < .0001), with the slope of this curve different (P = .002) from the unchanged IR exhibited by women who developed T2DM and different (P = .017) from an increased IR slope (P = .049) in women who had GD. In women with PCOS, pretreatment glucose and IR, and lesser reduction in IR on metformin diet were associated with T2DM and GD.

Gestational diabetes has no additional effect on plasma thrombin-activatable fibrinolysis inhibitor antigen levels beyond pregnancy

Pregnancy is a prothrombotic condition with increased levels of several circulating coagulation factors. Decreased fibrinolytic activity has been shown in gestational diabetes. Gestational diabetes has been found to be associated with higher plasma plasminogen activator inhibitor-1 (PAI-1) antigen levels than normal pregnancy. The aim of the present study is to investigate the effect of gestational diabetes on plasma thrombin-activatable fibrinolysis inhibitor (TAFI) antigen levels. Plasma TAFI and PAI-1 antigen levels were measured in 26 pregnant women with gestational diabetes, 25 pregnant women with normal glucose tolerance, and age-matched 24 non-pregnant women with no history of gestational diabetes. Increased plasma TAFI antigen levels were found in pregnant women compared to non-pregnant controls. However, no statistically significant difference in TAFI antigen levels was observed between women with gestational diabetes and pregnant controls. Plasma PAI-1 antigen levels were higher in gestational diabetes than pregnant and non-pregnant controls. Our study revealed that pregnancy was associated with elevated plasma TAFI antigen levels. However, no additional effect of gestational diabetes was found on plasma TAFI antigen levels beyond pregnancy. We suggest that pregnancy is associated with enhanced coagulation and impaired fibrinolysis. Despite increased PAI-1 antigen levels associated with gestational diabetes, the effect of gestational diabetes on TAFI antigen levels is lacking.

Prevention of gestational diabetes by metformin plus diet in patients with polycystic ovary syndrome

OBJECTIVE

To prospectively assess whether metformin diet safely provides primary and secondary prevention of gestational diabetes (GD).

DESIGN

Assess development of GD on metformin diet.

SETTING

Outpatient clinical research center.

PATIENT(S)

One hundred forty-two nondiabetic women with polycystic ovary syndrome (PCOS) who had at least one live-birth (LB) pregnancy on metformin diet (172 pregnancies, 180 LBs).

INTERVENTION(S)

Women were given 26% protein, 44% carbohydrate diets, without calorie restriction during pregnancy. Metformin (2-2.55 g/d) was given preconception, through pregnancy.

MAIN OUTCOME MEASURE(S)

Development of GD.

RESULT(S)

On metformin, GD developed in 12 (7%) of 172 LB pregnancies. Forty-seven women had at least one previous LB pregnancy (n = 64) without metformin, with GD developing in 19 (30%). Subsequently, on metformin, these 47 women had 50 LB pregnancies, developing GD in 6 (12%), which was a statistically significant difference. Of 15 women who had previous GD without metformin, GD developed in 5 (31%) of 16 subsequent pregnancies on metformin. Of 32 women who were previously free of GD without metformin, GD developed in 1 (3%) of 34 subsequent pregnancies on metformin. Previous GD without metformin was the only statistically significant explanatory variable for current GD on metformin.

CONCLUSION(S)

Metformin diet during pregnancy in women with PCOS facilitates primary and secondary prevention of GD.