Fetal macrosomia and neonatal hyperinsulinemic hypoglycemia associated with transplacental transfer of sulfonylurea in a mother with KCNJ11-related neonatal diabetes

Analysis of risk factors and construction of a predictive model for macrosomia in deliveries with gestational diabetes

BACKGROUND

Gestational diabetes, a frequent pregnancy complication marked by elevated maternal blood glucose, can cause serious adverse effects for both mother and fetus, including increased amniotic fluid and risks of fetal asphyxia, hypoxia, and premature birth.

OBJECTIVE

To construct a predictive model to analyze the risk factors for macrosomia in deliveries with gestational diabetes.

METHODS

From January 2021 to February 2023, 362 pregnant women with gestational diabetes were selected for the study. They were followed up until delivery. Based on newborn birth weight, the participants were divided into the macrosomia group (birth weight ⩾ 4000 g) and the non-macrosomia group (birth weight < 4000 g). The data of the two groups of pregnant women were compared. ROC curves were plotted to analyze the predictive value of multiple factors for the delivery of macrosomic infants among pregnant women with gestational diabetes. A logistic regression model was constructed to identify the risk factors for delivering macrosomic infants and the model was tested.

RESULTS

A total of 362 pregnant women with gestational diabetes were included, of which 58 (16.02%) had babies with macrosomia. The macrosomia group exhibited higher metrics in several areas compared to those without: pre-pregnancy BMI, fasting glucose, 1 h and 2 h OGTT sugar levels, weight gain during pregnancy, and levels of triglycerides, LDL-C, and HDL-C, all with significant differences (P< 0.05). ROC analysis revealed predictive value for macrosomia with AUCs of 0.761 (pre-pregnancy BMI), 0.710 (fasting glucose), 0.671 (1 h OGTT), 0.634 (2 h OGTT), 0.850 (weight gain), 0.837 (triglycerides), 0.742 (LDL-C), and 0.776 (HDL-C), indicating statistical significance (P< 0.05). Logistic regression identified high pre-pregnancy BMI, fasting glucose, weight gain, triglycerides, and LDL-C levels as independent risk factors for macrosomia, with odds ratios of 2.448, 2.730, 1.884, 16.919, and 5.667, respectively, and all were statistically significant (P< 0.05). The model's AUC of 0.980 (P< 0.05) attests to its reliability and stability.

CONCLUSION

The delivery of macrosomic infants in gestational diabetes may be related to factors such as body mass index before pregnancy, blood-glucose levels, gain weight during pregnancy, and lipid levels. Clinical interventions targeting these factors should be implemented to reduce the incidence of macrosomia.

Role of Actionable Genes in Pursuing a True Approach of Precision Medicine in Monogenic Diabetes

Monogenic diabetes is a genetic disorder caused by one or more variations in a single gene. It encompasses a broad spectrum of heterogeneous conditions, including neonatal diabetes, maturity onset diabetes of the young (MODY) and syndromic diabetes, affecting 1-5% of patients with diabetes. Some of these variants are harbored by genes whose altered function can be tackled by specific actions ("actionable genes"). In suspected patients, molecular diagnosis allows the implementation of effective approaches of precision medicine so as to allow individual interventions aimed to prevent, mitigate or delay clinical outcomes. This review will almost exclusively concentrate on the clinical strategy that can be specifically pursued in carriers of mutations in "actionable genes", including ABCC8, KCNJ11, GCK, HNF1A, HNF4A, HNF1B, PPARG, GATA4 and GATA6. For each of them we will provide a short background on what is known about gene function and dysfunction. Then, we will discuss how the identification of their mutations in individuals with this form of diabetes, can be used in daily clinical practice to implement specific monitoring and treatments. We hope this article will help clinical diabetologists carefully consider who of their patients deserves timely genetic testing for monogenic diabetes.

Comparison of diabetes phenotype in children and their mothers with permanent neonatal diabetes mellitus carrying the same KCNJ11 variants

Objective. Mutations of the KCNJ11 gene are the most common cause of the permanent neonatal diabetes mellitus (PNDM). Majority of people with KNCJ11-PNDM have a de-novo mutation. We aimed to compare diabetes phenotype in two children and their mothers with PNDM carrying the same sulfonylurea-sensitive KCNJ11 variants.Methods. We have compared glibenclamide (sulfonylurea) dose, C-peptide, and HbA1c serum levels in two children and their mothers with PNDM up to 5.5-year follow-up. All of them were carrying a heterozygous activating KCNJ11 pathogenic variant (p.R201H in Family 1 or p.H46Y in Family 2). The mothers were initially treated with insulin and successfully switched to sulfonylurea at the age of 24 and 11 years, respectively. Both children were treated with sulfonylurea since the diagnosis of PNDM.Results. Glibenclamide dose was similar in both children (0.02-0.03 mg/kg/day), but lower compared to their mothers (0.1-0.4 mg/kg/day) (p<0.002). Fasting serum C-peptide levels were also lower in children (70-210 pmol/l) than in their mothers (263-720 pmol/l) (p<0.002), but no significant differences were observed in postprandial C-peptide levels. HbA1c was lower only in the son of SVK4 (Family 2) compared to his mother, as she had poor adherence to the sulfonylurea therapy during the first years after the sulfonylurea switch.Conclusions. Evaluation of the treatment in people with sulfonylurea-sensitive KNCJ11-PNDM should respect the age of patients together with the type of mutation and duration of diabetes at therapy start and may differ within one family.

New insights into KATP channel gene mutations and neonatal diabetes mellitus

The ATP-sensitive potassium channel (K_ATP channel) couples blood levels of glucose to insulin secretion from pancreatic β-cells. K_ATP channel closure triggers a cascade of events that results in insulin release. Metabolically generated changes in the intracellular concentrations of adenosine nucleotides are integral to this regulation, with ATP and ADP closing the channel and MgATP and MgADP increasing channel activity. Activating mutations in the genes encoding either of the two types of K_ATP channel subunit (Kir6.2 and SUR1) result in neonatal diabetes mellitus, whereas loss-of-function mutations cause hyperinsulinaemic hypoglycaemia of infancy. Sulfonylurea and glinide drugs, which bind to SUR1, close the channel through a pathway independent of ATP and are now the primary therapy for neonatal diabetes mellitus caused by mutations in the genes encoding K_ATP channel subunits. Insight into the molecular details of drug and nucleotide regulation of channel activity has been illuminated by cryo-electron microscopy structures that reveal the atomic-level organization of the K_ATP channel complex. Here we review how these structures aid our understanding of how the various mutations in the genes encoding Kir6.2 (KCNJ11) and SUR1 (ABCC8) lead to a reduction in ATP inhibition and thereby neonatal diabetes mellitus. We also provide an update on known mutations and sulfonylurea therapy in neonatal diabetes mellitus.

Update of variants identified in the pancreatic β-cell KATP channel genes KCNJ11 and ABCC8 in individuals with congenital hyperinsulinism and diabetes

The most common genetic cause of neonatal diabetes and hyperinsulinism is pathogenic variants in ABCC8 and KCNJ11. These genes encode the subunits of the β-cell ATP-sensitive potassium channel, a key component of the glucose-stimulated insulin secretion pathway. Mutations in the two genes cause dysregulated insulin secretion; inactivating mutations cause an oversecretion of insulin, leading to congenital hyperinsulinism, whereas activating mutations cause the opposing phenotype, diabetes. This review focuses on variants identified in ABCC8 and KCNJ11, the phenotypic spectrum and the treatment implications for individuals with pathogenic variants.

Monogenic Forms of Diabetes Mellitus

In addition to the common types of diabetes mellitus, two major monogenic diabetes forms exist. Maturity-onset diabetes of the young (MODY) represents a heterogenous group of monogenic, autosomal dominant diseases. MODY accounts for 1-2% of all diabetes cases, and it is not just underdiagnosed but often misdiagnosed to type 1 or type 2 diabetes. More than a dozen MODY genes have been identified to date, and their molecular classification is of great importance in the correct treatment decision and in the judgment of the prognosis. The most prevalent subtypes are HNF1A, GCK, and HNF4A. Genetic testing for MODY has changed recently due to the technological advancements, as contrary to the sequential testing performed in the past, nowadays all MODY genes can be tested simultaneously by next-generation sequencing. The other major group of monogenic diabetes is neonatal diabetes mellitus which can be transient or permanent, and often the diabetes is a part of a syndrome. It is a severe monogenic disease appearing in the first 6 months of life. The hyperglycemia usually requires insulin. There are two forms, permanent neonatal diabetes mellitus (PNDM) and transient neonatal diabetes mellitus (TNDM). In TNDM, the diabetes usually reverts within several months but might relapse later in life. The incidence of NDM is 1:100,000-1:400,000 live births, and PNDM accounts for half of the cases. Most commonly, neonatal diabetes is caused by mutations in KCNJ11 and ABCC8 genes encoding the ATP-dependent potassium channel of the β cell. Neonatal diabetes has experienced a quick and successful transition into the clinical practice since the discovery of the molecular background. In case of both genetic diabetes groups, recent guidelines recommend genetic testing.

Pharmacotherapy for hyperglycemia in pregnancy - Do oral agents have a place?

Diabetes is a frequent condition in pregnancy and achieving adequate glycemic control is of paramount importance. Insulin treatment is the gold standard, oral agents are more attractive, but their safety and efficiency should be a prerequisite for their use. We have more information regarding treatment of women with gestational diabetes mellitus where glyburide can induce a picture of fetal hyperinsulinism (higher birthweight and more neonatal hypoglycemia) whereas metformin requires supplemental insulin in a larger proportion of women but achieves satisfactory perinatal outcomes with the exception of preterm birth. Information in patients with Type 2 Diabetes Mellitus is much more limited but also favors metformin. Combinations provide additional possibilities. However, as to long-term outcomes, we have no information on the impact of exposure to glyburide and it is still unclear if in utero exposure to metformin will have any effect on the offspring and the direction of this effect. Women prefer oral agents, indicating the need of additional studies.

Binding of sulphonylureas to plasma proteins - A KATP channel perspective

Sulphonylurea drugs stimulate insulin secretion from pancreatic β-cells primarily by inhibiting ATP sensitive potassium (K_ATP) channels in the β-cell membrane. The effective sulphonylurea concentration at its site of action is significantly attenuated by binding to serum albumin, which makes it difficult to compare in vitro and in vivo data. We therefore measured the ability of gliclazide and glibenclamide to inhibit K_ATP channels and stimulate insulin secretion in the presence of serum albumin. We used this data, together with estimates of free drug concentrations from binding studies, to predict the extent of sulphonylurea inhibition of K_ATP channels at therapeutic concentrations in vivo. K_ATP currents from mouse pancreatic β-cells and Xenopus oocytes were measured using the patch-clamp technique. Gliclazide and glibenclamide binding to human plasma were determined in spiked plasma samples using an ultrafiltration-mass spectrometry approach. Bovine serum albumin (60g/l) produced a mild, non-significant reduction of gliclazide block of K_ATP currents in pancreatic β-cells and Xenopus oocytes. In contrast, glibenclamide inhibition of recombinant K_ATP channels was dramatically suppressed by albumin (predicted free drug concentration <0.1%). Insulin secretion was also reduced. Free concentrations of gliclazide and glibenclamide in the presence of human plasma measured in binding experiments were 15% and 0.05%, respectively. Our data suggest the free concentration of glibenclamide in plasma is too low to account for the drug’s therapeutic effect. In contrast, the free gliclazide concentration in plasma is high enough to close K_ATP channels and stimulate insulin secretion.

Clinical Management of Women with Monogenic Diabetes During Pregnancy

PURPOSE OF REVIEW

Monogenic diabetes accounts for 1-2% of all diabetes cases, but is frequently misdiagnosed as type 1, type 2, or gestational diabetes. Accurate genetic diagnosis directs management, such as no pharmacologic treatment for GCK-MODY, low-dose sulfonylureas for HNF1A-MODY and HNF4A-MODY, and high-dose sulfonylureas for K_ATP channel-related diabetes. While diabetes treatment is defined for the most common causes of monogenic diabetes, pregnancy poses a challenge to management. Here, we discuss the key issues in pregnancy affected by monogenic diabetes.

RECENT FINDINGS

General recommendations for pregnancy affected by GCK-MODY determine need for maternal insulin treatment based on fetal mutation status. However, a recent study suggests macrosomia and miscarriage rates may be increased with this strategy. Recent demonstration of transplacental transfer of sulfonylureas also raises questions as to when insulin should be initiated in sulfonylurea-responsive forms of monogenic diabetes. Pregnancy represents a challenge in management of monogenic diabetes, where factors of maternal glycemic control, fetal mutation status, and transplacental transfer of medication must all be taken into consideration. Guidelines for pregnancy affected by monogenic diabetes will benefit from large, prospective studies to better define the need for and timing of initiation of insulin treatment.

Management of sulfonylurea-treated monogenic diabetes in pregnancy: implications of placental glibenclamide transfer

The optimum treatment for HNF1A/HNF4A maturity-onset diabetes of the young and ATP-sensitive potassium (K_ATP ) channel neonatal diabetes, outside pregnancy, is sulfonylureas, but there is little evidence regarding the most appropriate treatment during pregnancy. Glibenclamide has been widely used in the treatment of gestational diabetes, but recent data have established that glibenclamide crosses the placenta and increases risk of macrosomia and neonatal hypoglycaemia. This raises questions about its use in pregnancy. We review the available evidence and make recommendations for the management of monogenic diabetes in pregnancy. Due to the risk of stimulating increased insulin secretion in utero, we recommend that in women with HNF1A/ HNF4A maturity-onset diabetes of the young, those with good glycaemic control who are on a sulfonylurea per conception either transfer to insulin before conception (at the risk of a short-term deterioration of glycaemic control) or continue with sulfonylurea (glibenclamide) treatment in the first trimester and transfer to insulin in the second trimester. Early delivery is needed if the fetus inherits an HNF4A mutation from either parent because increased insulin secretion results in ~800-g weight gain in utero, and prolonged severe neonatal hypoglycaemia can occur post-delivery. If the fetus inherits a K_ATP neonatal diabetes mutation from their mother they have greatly reduced insulin secretion in utero that reduces fetal growth by ~900 g. Treating the mother with glibenclamide in the third trimester treats the affected fetus in utero, normalising fetal growth, but is not desirable, especially in the high doses used in this condition, if the fetus is unaffected. Prospective studies of pregnancy in monogenic diabetes are needed.

Neonatal Diabetes and the KATP Channel: From Mutation to Therapy

Activating mutations in one of the two subunits of the ATP-sensitive potassium (K_ATP) channel cause neonatal diabetes (ND). This may be either transient or permanent and, in approximately 20% of patients, is associated with neurodevelopmental delay. In most patients, switching from insulin to oral sulfonylurea therapy improves glycemic control and ameliorates some of the neurological disabilities. Here, we review how K_ATP channel mutations lead to the varied clinical phenotype, how sulfonylureas exert their therapeutic effects, and why their efficacy varies with individual mutations.

Analysis of cell-free fetal DNA for non-invasive prenatal diagnosis in a family with neonatal diabetes

AIMS

An early genetic diagnosis of neonatal diabetes guides clinical management and results in improved treatment in ~ 40% of patients. In the offspring of individuals with neonatal diabetes, a prenatal diagnosis allows accurate estimation of the risk of developing diabetes and, eventually, the most appropriate treatment for the baby. In this study, we performed non-invasive prenatal genetic testing for a fetus at risk of inheriting a paternal KCNJ11 p.R201C mutation causing permanent neonatal diabetes.

METHODS

A droplet digital polymerase chain reaction assay was used to detect the presence of the mutation in cell-free circulating DNA (cfDNA) extracted from maternal plasma at 12 and 16 weeks' gestation.

RESULTS

The mutation was not detected in the cfDNA samples, suggesting that the fetus had not inherited the KCNJ11 mutation. The fetal DNA fraction was estimated at 6.2% and 10.7%, which is above the detection limit of the assay. The result was confirmed by Sanger sequencing after the baby's birth, confirming that the baby's risk of developing neonatal diabetes was reduced to that of the general population.

CONCLUSIONS

We report the first case of non-invasive prenatal testing in a family with neonatal diabetes. A prenatal diagnosis in families at high risk of monogenic diabetes informs both prenatal and postnatal management. Although the clinical impact of this novel technology still needs to be assessed, its implementation in clinical practice (including cases at risk of inheriting mutations from the mother) will likely have a positive impact upon the clinical management of families affected by monogenic diabetes.

Pharmacokinetics, efficacy and safety of glyburide for treatment of gestational diabetes mellitus

INTRODUCTION

Gestational diabetes mellitus (GDM) complicates 10% of all pregnancies and is defined as hyperglycemia first noted during pregnancy. Rates of GDM are rising and untreated GDM results in complications for both mother and fetus. GDM is often managed by diet and exercise but 30-40% of women will require pharmacological intervention. Insulin has traditionally been the treatment of choice but since 2007, glyburide, a second generation sulfonylurea has become the most prescribed medication for GDM.

AREAS COVERED

This review will cover the pharmacokinetics, efficacy, and safety of glyburide for the management of GDM.

EXPERT OPINION

Management of GDM is challenging secondary to the stringent glycemic goals that mimic the lower glucose levels in pregnancy. Glyburide is generally effective in treating hyperglycemia. However, several studies have raised safety concerns showing higher neonatal intensive care unit (NICU) admissions, higher rates of macrosomia, large for gestational age and pre-eclampsia in the mother. For this reason, insulin should be first-line therapy for GDM. In areas of limited resources where the self-monitoring needed for accurate insulin dosing is not possible, where access to refrigeration for insulin storage is not universal, or severe needle phobia then the benefits of glyburide (controlling hyperglycemia) outweighs the harm of NICU admissions and macrosomia.

Differences in pregnancy outcomes and characteristics between insulin- and diet-treated women with gestational diabetes

Background

Our aim was to evaluate the difference in pregnancy outcomes and characteristics between insulin- and diet-treated women with gestational diabetes (GDM).

Methods

Retrospective analysis of the medical files from 2010–2013 of women with GDM diagnosed with the Carpenter & Coustan criteria attending two clinics, one in a university and another in a non-university hospital. Characteristics associated with insulin use were analyzed. Multivariable logistic regression was used to adjust for confounders. For women attending the university hospital, indices of insulin sensitivity such as the reciprocal of the homeostasis model assessment of insulin resistance (1/HOMA-IR) and an index of beta-cell function, the Insulin Secretion-Sensitivity Index-2 (ISSI-2) were calculated.

Results

Over a 4 year period, 601 women were identified with GDM of whom 22.9 % were obese at first prenatal visit. 24.2 % needed insulin. Insulin did not prevent adverse outcomes, as women on insulin had higher rates of large-for-gestational age infants (LGA) (28.5 % vs. 13.1 %, p < 0.0001) and more cesarean sections (44.1 % vs. 27.0 %, p = 0.001), remaining significant after adjustment for confounders. Compared to diet-treated women, women on insulin more often had an ethnic minority background (33.3 % vs. 21.6 %, p = 0.004), more often had a history of GDM (21.5 % vs. 10.4 %, p = 0.002), were more often multiparous (59.3 % vs. 47.6 %, p = 0.044) and were diagnosed with GDM earlier in pregnancy (weeks 25.3 ± 4.9 vs. 27.1 ± 3.7, p < 0.0001). When undergoing an oral glucose tolerance test, women treated with insulin had a higher fasting glycaemia (97.6 ± 18.8 vs.87.7 ± 10.3, p < 0.0001), a higher 1-hour glycaemia (197.7 ± 30.1 vs.184.5 ± 25.8, p < 0.0001), a higher 2-hour glycaemia (185.2 ± 28.5 vs. 175.0 ± 22.8, p < 0.0001), more often 3 and 4 abnormal values (58.1 % vs. 37.8 %, p < 0.0001 and 24.8 % vs. 7.7 %, p < 0.0001) and higher HbA1c levels (5.5 ± 0.6 vs 5.2 ± 0.5, p < 0.0001). ISSI-2 (1.3 ± 0.5 vs. 1.7 ± 0.5, p < 0.0001) and 1/HOMA-IR [0.01 (0.001–0.002) vs. 0.02 (0.01–0.03), p = 0.027] were lower in women on insulin. Women on insulin more often received corticoids in preparation of preterm delivery (11.0 % vs. 2.4 %, p < 0.0001).

Conclusion

Compared to diet-treated women with GDM, women treated with insulin have a higher risk profile, impaired beta-cell function and lower insulin sensitivity. Rates of LGA and cesarean sections were higher in insulin-treated women.

The value of in vitro studies in a case of neonatal diabetes with a novel Kir6.2-W68G mutation

In infants, especially with novel previously undescribed mutations of the K_ATP channel causing neonatal diabetes, in vitro studies can be used to both predict the response to sulphonylurea treatment and support a second trial of glibenclamide at higher than standard doses if the expected response is not observed.

Systemic Administration of Glibenclamide Fails to Achieve Therapeutic Levels in the Brain and Cerebrospinal Fluid of Rodents

Activating mutations in the Kir6.2 (KCNJ11) subunit of the ATP-sensitive potassium channel cause neonatal diabetes (ND). Patients with severe mutations also suffer from neurological complications. Glibenclamide blocks the open KATP channels and is the treatment of choice for ND. However, although glibenclamide successfully restores normoglycaemia, it has a far more limited effect on the neurological problems. To assess the extent to which glibenclamide crosses the blood-brain barrier (BBB) in vivo, we quantified glibenclamide concentrations in plasma, cerebrospinal fluid (CSF), and brain tissue of rats, control mice, and mice expressing a human neonatal diabetes mutation (Kir6.2-V59M) selectively in neurones (nV59M mice). As only small sample volumes can be obtained from rodents, we developed a highly sensitive method of analysis, using liquid chromatography tandem mass spectrometry acquisition with pseudo-selected reaction monitoring, achieving a quantification limit of 10ng/ml (20nM) glibenclamide in a 30μl sample. Glibenclamide was not detectable in the CSF or brain of rats after implantation with subcutaneous glibenclamide pellets, despite high plasma concentrations. Further, one hour after a suprapharmacological glibenclamide dose was administered directly into the lateral ventricle of the brain, the plasma concentration was twice that of the CSF. This suggests the drug is rapidly exported from the CSF. Elacridar, an inhibitor of P-glycoprotein and breast cancer resistance protein (major multidrug resistance transporters at the BBB), did not affect glibenclamide levels in CSF and brain tissue. We also identified a reduced sensitivity to volatile anaesthetics in nV59M mice and showed this was not reversed by systemic delivery of glibenclamide. Our results therefore suggest that little glibenclamide reaches the central nervous system when given systemically, that glibenclamide is rapidly removed across the BBB when given intracranioventricularly, and that any glibenclamide that does enter (and is below our detection limit) is insufficient to influence neuronal function as assessed by anaesthesia sensitivity.