The infant of the diabetic mother

Insulin Use During Gestational and Pre-existing Diabetes in Pregnancy: A Systematic Review of Study Design

INTRODUCTION

Insulin is the first-line pharmacologic therapy for women with diabetes in pregnancy. However, conducting well-designed randomized clinical trials (RCTs) and achieving recommended glycemic targets remains a challenge for this unique population. This systematic literature review (SLR) aimed to understand the evidence for insulin use in pregnancy and the outcome metrics most often used to characterize its effect on glycemic, maternal and fetal outcomes in gestational diabetes mellitus (GDM) and in pregnant women with diabetes.

METHODS

An SLR was conducted using electronic databases in Medline, EMBASE via Ovid platform, evidence-based medicine reviews (2010-2020) and conference proceedings (2018-2019). Studies were included if they assessed the effect of insulin treatment on glycemic, maternal or fetal outcomes in women with diabetes in pregnancy. Studies on any type of diabetes other than gestational or pre-existing diabetes as well as non-human studies were excluded.

RESULTS

In women diagnosed with GDM or pre-existing diabetes, most studies compared treatment of insulin with metformin (n = 35) followed by diet along with lifestyle intervention (n = 24) and glibenclamide (n = 12). Most studies reporting on glycemic outcomes compared insulin with metformin (n = 22) and glibenclamide (n = 4). Fasting blood glucose was the most reported clinical outcome of interest. Among the studies reporting maternal outcomes, method of delivery and delivery complications were most commonly reported. Large for gestational age, stillbirth and perinatal mortality were the most common fetal outcomes reported.

CONCLUSION

This SLR included a total of 108 clinical trials and observational studies with diverse populations and treatment arms. Outcomes varied across the studies, and a lack of consistent outcome measures to manage diabetes in pregnant women was observed. This elucidates a need for global consensus on study design and standardized clinical, maternal and fetal outcomes metrics.

Maternal diabetes negatively impacts fetal health

Diabetes is a chronic metabolic disease affecting an increasing number of people. Although diabetes has negative health outcomes for diagnosed individuals, a population at particular risk are pregnant women, as diabetes impacts not only a pregnant woman's health but that of her child. In this review, we cover the current knowledge and unanswered questions on diabetes affecting an expectant mother, focusing on maternal and fetal outcomes.

High expression of an unknown long noncoding RNA RP11-290L1.3 from GDM macrosomia and its effect on preadipocyte differentiation

AIMS

Gestational diabetes mellitus (GDM)-induced macrosomia is predominantly characterized by fat accumulation, which is closely related to adipocyte differentiation. An unknown long noncoding RNA RP11-290L1.3, referred to as RP11, was identified to be dramatically upregulated in the umbilical cord blood of women with GDM-induced macrosomia in our previous study. We conducted this study to identify the function of RP11 in GDM-induced macrosomia.

METHODS

The effects of RP11 gain- and loss-of-function on HPA-v (human preadipocytes-visceral) adipogenesis were determined with lentivirus mediated cell transduction. The mRNA and protein expression levels of adipogenesis makers were evaluated by qPCR/Western blot. Then, we performed the microarray and pathway analysis to explore the possible mechanisms by which RP11 regulates adipogenesis.

RESULTS

Overexpression of RP11 significantly enhanced adipocyte differentiation and increased the mRNA and protein expression levels of adipogenesis makers, such as PPARγ, SREBP1c, and FASN by qPCR/Western blot. Knockdown of RP11 showed opposite effects. Microarray and pathway analysis showed, after RP11 knockdown, 1612 genes were upregulated, and 583 genes were down-regulated which were found to be mainly involved in metabolic pathways, insulin signaling pathway and MAPK signaling pathway.

CONCLUSION

In conclusion, the unknown lncRNA RP11 serves as a positive factor on preadipocyte differentiation which could shed light on fetal fat accumulation in GDM.

Cardiac Function in Infants Born to Mothers With Gestational Diabetes - Estimation of Early Diastolic Intraventricular Pressure Differences

Background: This study compared the myocardial performance of infants born to mothers with gestational diabetes mellitus (IGDM) and without GDM (controls) under the new GDM definitions.

Methods and Results: The subjects consisted of 36 IGDM and 39 control infants. GDM diagnosis was based on oral glucose tolerance test during pregnancy or the presence of diabetes prior to the current pregnancy. Between-group infant cardiac function was determined and compared using 2-D speckle tracking analysis, intraventricular pressure difference (IVPD) and IVP gradient (IVPG), using color M-mode Doppler imaging. IVPD and IVPG were higher in IGDM than in the controls, particularly the mid–apical IVPG. The global circumferential strain (GCS) and endocardial GCS were higher in IGDM than in controls. Increased maternal glycated hemoglobin was correlated with reduced transmural and epicardial GCS in the IGDM. Maternal maximum fasting blood sugar had a mild, positive correlation with IVPD and IVPG.

Conclusions: Ventricular sucking force, measured as the IVPD, IVPG, and endocardial GCS, were higher in IGDM than in the controls. A hyperglycemic environment during pregnancy leads to impaired cardiac performance in IGDM, compared with control infants. IGDM might have favorable systolic and diastolic cardiac performance due to cardiac metabolic adaptations occurring before poor glucose control causes impaired cardiac performance.

Infant of diabetic mother: what one needs to know?

The global incidence of diabetes mellitus, including diabetes in pregnant women, is on the rise. Diabetes mellitus in a pregnant woman jeopardizes not only maternal health but can also have significant implications on the child to be born. Therefore, timely diagnosis and strict glycemic control are of utmost importance in achieving a safe outcome for both the mother and fetus. The treating physician should be aware of the complications that can arise due to poor glycemic control during pregnancy. The objective of this article is to discuss the key concerns in a neonate born to diabetic mother, the underlying pathogenesis, and the screening schedule during pregnancy.

HYDROCEPHALY, SCHIZENCEPHALY, SPONDYLOCOSTAL DYSPLASIA, AND HYPOPARATHYROIDISM IN AN INFANT OF A DIABETIC MOTHER

CONTEXT

Diabetes mellitus is the most frequent chronic complication in pregnancy and continues to contribute to increased perinatal morbidity and mortality in newborns. Macrosomia, respiratory distress syndrome, metabolic and electrolytic disturbances, and increased rates of congenital structural defects are well-known neonatal complications associated with maternal diabetes, even if well-controlled.

CASE REPORT

A macrosomic infant born from an insulin-dependent mother, with uncontrolled diabetes and lack of adequate prenatal care, prenatally diagnosed with hydrocephaly showed a complicated postnatal course. Initial respiratory distress syndrome and transient hypoglycemia, rapidly corrected under treatment, were followed by persistent hypocalcemia and hyperphosphatemia due to hypoparathyroidism and evolving hydrocephaly. Ventriculoperitoneal shunting was followed by resolution of hypocalcemia, but seizures associated with schizencephaly and recurrent respiratory tract infections, aggravated by spondylocostal dysplasia, concurred to infant's demise at the age of 5 months.

CONCLUSIONS

The reported case is rare due to multiple aspects: persistent hypoparathyroidism, uncommon association of schizencephaly, and even rarely association with spondylocostal dysplasia, all these conditions requiring a multidisciplinary therapeutic approach. Also, the reported case is evocative for challenges associated with infants born from diabetic mothers.

Three patients presenting with severe macrosomia and congenital hypertrophic cardiomyopathy: a case series

Background

Macrosomia and hypertrophic cardiomyopathy are two features often associated in neonates of diabetic mothers. We report the cases of three patients with severe macrosomia and critical hypertrophic cardiomyopathy without severely unbalanced maternal diabetes. Only three patients with those two features and no uncontrolled maternal diabetes have been previously reported.

Case presentation

The first patient was a 39-week-old girl, the second patient was a 39-week-old girl, and the third patient was a 41-week-old boy. The two French girls and the French boy had severe macrosomia and hypertrophic cardiomyopathy, leading to the death of the boy. The outcome of the two girls was favorable, with a standardization of growth curves and ventricular hypertrophy. Their mothers presented with high body mass index but no severe documented maternal diabetes; glycemic imbalance was only suspected on postnatal analyses. There was no hydramnios during pregnancy and no other environmental factor, especially toxic exposure. Their parents are from Mayotte, Guadeloupe, and Guinea-Conakry. The usual genetics causes, Beckwith–Wiedemann syndrome, and chromosomal copy number variation, were also excluded.

Conclusions

This report suggests the implication of other factors in addition to glycemic disorders, including genetic factors, in the occurrence of macrosomia and severe hypertrophic cardiomyopathy in neonates. These three original observations indicate that gynecologists and neonatologists should pay attention to neonates from mothers with a high body mass index and when maternal diabetes is not documented.

Electronic supplementary material

The online version of this article (doi:10.1186/s13256-017-1231-5) contains supplementary material, which is available to authorized users.

Hypertrophic cardiomyopathy in neonates with congenital hyperinsulinism

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) is a well-recognised complication in infants of diabetic mothers and is attributed to a compensatory increase in fetal insulin secretion. Infants with congenital hyperinsulinism have excessive prenatal and postnatal insulin secretion due to defects in pathways of insulin secretion (most commonly the KATP channel). HCM has been reported in a few neonates with hyperinsulinism, but its extent and risk factors for its development have not been evaluated.

METHODS

Retrospective chart review of infants, age <3 months, with congenital hyperinsulinism managed by Children's Hospital of Philadelphia over a 3.5-year period.

DATA

Gestational age, birth weight, hyperinsulinism form and treatments, echocardiogram results, cardiac/respiratory complications.

RESULTS

68 infants were included, 58 requiring pancreatectomy for diffuse (n=28) or focal (n=30) disease, 10 were diazoxide-sensitive. Twenty-five had echocardiograms performed. Ten had HCM, all of whom required pancreatectomy and eight of whom had confirmed ATP-sensitive potassium-hyperinsulinism. Subjects with HCM had younger gestational age 36(32, 38) than their surgical counterparts without HCM 38 (31.6, 43), p=0.02.

DISCUSSION

HCM appears common in infants with severe hyperinsulinism. Routine echocardiogram and EKG of at-risk newborns should be considered. Fetal hyperinsulinism is the likely mediating factor for HCM in HI infants.

Polycythaemia in infants of diabetic mothers: β-hydroxybutyrate stimulates erythropoietic activity

This study tested whether elevated maternal β-hydroxybutyrate (β-OHB) levels contribute to polycythaemia in infants of diabetic mothers. Pregnant diabetic women (n = 27) and non-diabetic controls (n = 20) and their singleton infants were included. Maternal glycosylated haemoglobin and β-OHB levels were studied at 34-36 weeks' gestation; levels were significantly higher in mothers with diabetes than in controls. Birth weights and cord blood levels of insulin and fetal haemoglobin were significantly higher in infants from diabetic mothers compared with control infants, as were haematocrit levels in venous blood samples taken from each infant at 4 h following delivery. Cord blood erythropoietin levels were similar in both groups. There was a positive strong correlation between maternal β-OHB levels and polycythaemia in newborn infants, indicating that β-OHB could activate erythropoiesis independently from intrauterine hyperinsulinaemia and/or erythropoietin levels, and may be important in the pathogenesis of polycythaemia in infants born to diabetic mothers.

Absence of increase in carotid artery intima-media thickness in infants of diabetic mothers

OBJECTIVE

Infants of diabetic mothers (IDM) are considered as a risk group for atherosclerosis. Increased aortic intima-media thickness has been reported in IDM. The purpose of this study was to assess carotid artery intima-media thickness (CA-IMT), left ventricular mass index (LVMI) and atherosclerotic risk factors in IDM.

METHODS

Thirty IDM and 25 healthy controls were included in the study. Of these infants, 14 were appropriate-for-gestational age (AGA) and 16 were large-for-gestational age (LGA). CA-IMT and LVMI were obtained by M-mode echocardiographic examination. The relationship between parameters of atherosclerosis and echocardiographic measurements was assessed by Pearson's correlation analysis.

RESULTS

LVMI was higher in LGA IDM when compared to AGA IDM and controls. CA-IMT was not significantly different between the groups and was also not related to atherosclerotic risk factors. Serum lipid and insulin levels were higher in LGA IDM when compared with AGA IDM and controls. There were no correlations between CA-IMT, LVMI and atherosclerotic risk factors.

CONCLUSIONS

In contrast to previous reports indicating an increase in CA-IMT in IDM, no differences were found between IDM and controls in this study. Our results indicate that macrosomic IDM are prone to hypertrophic cardiomyopathy but not to atherosclerotic changes in the blood vessels.

Whole-exome sequencing identifies compound heterozygous mutations in WDR62 in siblings with recurrent polymicrogyria

Polymicrogyria is a disorder of neuronal development resulting in structurally abnormal cerebral hemispheres characterized by over-folding and abnormal lamination of the cerebral cortex. Polymicrogyria is frequently associated with severe neurologic deficits including intellectual disability, motor problems, and epilepsy. There are acquired and genetic causes of polymicrogyria, but most patients with a presumed genetic etiology lack a specific diagnosis. Here we report using whole-exome sequencing to identify compound heterozygous mutations in the WD repeat domain 62 (WDR62) gene as the cause of recurrent polymicrogyria in a sibling pair. Sanger sequencing confirmed that the siblings both inherited 1-bp (maternal allele) and 2-bp (paternal allele) frameshift deletions, which predict premature truncation of WDR62, a protein that has a role in early cortical development. The probands are from a non-consanguineous family of Northern European descent, suggesting that autosomal recessive PMG due to compound heterozygous mutation of WDR62 might be a relatively common cause of PMG in the population. Further studies to identify mutation frequency in the population are needed.

Safety of insulin glargine use in pregnancy: a systematic review and meta-analysis

BACKGROUND

The prevalence of diabetes in women of childbearing age is increasing. As such, the number of pregnancies complicated by diabetes will inevitably increase. New insulin analogues such as the long-acting analogue insulin glargine may represent beneficial treatment options in pregnancy by ensuring that patients achieve excellent glycemic control without risk of maternal hypoglycemia.

OBJECTIVE

To determine the fetal safety of insulin glargine use in the treatment of diabetes in pregnancy compared with NPH insulin therapy.

METHODS

A systematic review and meta-analysis was performed of all original human studies that reported neonatal outcomes among women with pregestational or gestational diabetes who were managed with either insulin glargine or NPH insulin during pregnancy. A systematic literature search was conducted using MEDLINE, EMBASE, CINAHL, the Cochrane Central Register for Controlled Trials database, and Web of Science from 1980 to June 1, 2010. Outcomes included large size for gestational age, macrosomia, neonatal hypoglycemia, neonatal intensive care unit admissions, birth trauma, congenital anomalies, preterm delivery, perinatal mortality, respiratory distress, and hyperbilirubinemia. Relative risk ratios and weighted mean differences were computed with 95% confidence intervals.

RESULTS

Eight studies reporting on a total of 702 women with pregestational or gestational diabetes in pregnancy treated with either insulin glargine (n = 331) or NPH insulin (n = 371) met the inclusion criteria. There were no statistically significant differences in the occurrence of fetal outcomes studied with the use of insulin glargine compared to NPH insulin.

CONCLUSIONS

No evidence has been documented for increased adverse fetal outcomes with the use of insulin glargine in pregnancy compared to the use of NPH insulin. These results increase the choices for women requiring basal insulin therapy in pregnancy.

Pictorial Essay: Infants of diabetic mothers

About 3 to 10% of pregnancies are complicated by glycemic control abnormalities. Maternal diabetes results in significantly greater risk for antenatal, perinatal, and neonatal morbidity and mortality, as well as congenital malformations. The number of diabetic mothers is expected to rise, as more and more of the obese pediatric female population in developed and some developing countries progresses to childbearing age. Radiologists, being part of the teams managing such pregnancies, should be well aware of the findings that may be encountered in infants of diabetic mothers. Timely, accurate, and proper radiological evaluation can reduce morbidity and mortality in these infants. The purpose of this essay is to illustrate the imaging findings in the various pathological conditions involving the major body systems in the offspring of women with diabetes.

Maternal–fetal transport and disposition of copper, iron, molybdenum, selenium and zinc in experimentally induced diabetic rats

OBJECTIVE

To assess maternal-fetal status of essential trace elements such as copper, iron, molybdenum, selenium and zinc, in experimentally induced diabetic and control pregnant rats, and to correlate the findings with those observed in human diabetic pregnancies. Fetal-maternal ratios of the elements and Cu:Zn and Cu:Fe ratios were also computed in control and study groups.

METHODS

Diabetes was experimentally induced in pregnant Sprague Dawley rats by injection of streptozotocin. A cocktail of essential trace elements along with antipyrine as internal reference marker were then injected intra-peritoneally to diabetic and matched control pregnant rats on the 20th day of pregnancy. Maternal and fetal blood and tissue samples were collected after sacrificing the animals at 30- and 60-minutes following cocktail injection. Concentrations of trace elements and antipyrine in various blood and tissue samples were then determined by atomic absorption spectrophotometry and colorimetry, respectively.

RESULTS

Concentrations of Cu, Fe, Mo, Se, Zn, and antipyrine averaged 2907.0 +/- 212.0 microg/L, 3950.0 +/- 766.0 microg/L, 15.8 +/- 1.7 microg/L, 74.8 +/- 6.5 microg/L, 726.4 +/- 67.4 microg/L, and 170.5 +/- 8.2 mg/L, respectively, in maternal blood in control pregnant rats (n = 5) at day 20 in the 30-minute study phase, while in the diabetic group (n = 5) the values of the various trace element concentrations and antipyrine averaged 2875.0 +/- 225.0 microg/L, 5875.0 +/- 688.0 microg/L, 21.2 +/- 2.1 microg/L, 116.0 +/- 3.6 microg/L, 753.0 +/- 71.3 microg/L, and 171.7 +/- 4.2 mg/L, respectively. Unpaired student's t-test showed that Fe and Se levels were significantly higher (p < 0.05) in the diabetic pregnant rats compared to controls. Cu, Mo and Zn values, however, were not significantly different (p > 0.05) between the two groups. Cu:Zn and Cu:Fe ratios showed varying differences between maternal and fetal samples in the control and study groups.

CONCLUSIONS

Considering the disparity of results in pregnant diabetic rats and pregnant diabetic women, we urge exercising caution when comparing data from animal studies to human situations.

A community-based parish nurse intervention program for Mexican American women with gestational diabetes

OBJECTIVE

To examine the effects of a Parish Nurse Intervention Program (PNIP) on maternal health behaviors, glycemic control, and neonatal outcomes among Mexican American women with gestational diabetes.

DESIGN

A randomized controlled trial comparing care as usual (CAU) with a supplementary 1-hour education session for diabetes education reinforcement by a Parish Nurse.

SETTING

An outpatient treatment clinic for gestational diabetes within a 250-bed tertiary care, non-profit hospital with a Parish Nurse partnership.

PARTICIPANTS

One hundred Mexican American women were included in the study with randomization into Parish Nurse Intervention Program (n=49) and care as usual (n=51) groups.

MAIN OUTCOME MEASURES

The Health Promoting Lifestyle Profile II (HPLP II) and two measures of glycemic control pre- and post-intervention, as well as newborn size, and days of maternal and neonatal hospitalization.

RESULTS

Outcomes indicate significantly improved Health Promoting Lifestyle Profile II scores in the Parish Nurse Intervention Program group post-intervention compared with the Care As Usual group. No significant differences between groups regarding glycemic control, macrosomia, or days of maternal or neonatal hospitalization were found.

CONCLUSIONS

A Parish Nurse Intervention Program for pregnant women of Mexican descent with gestational diabetes is effective in leading to improved self-reported health promoting behaviors.

Insulins and oral hypoglycemic agents in pregnancy

Numerous studies have established a direct relationship between maternal levels of glycemic control and neonatal outcomes for pregnancies complicated by diabetes. The past several years have seen the addition of insulin analogues as well as many new oral agents to the pharmacological armamentarium available to treat diabetes. Insulin analogs (both rapid and long acting) are of potential interest for women with insulin-requiring diabetes because of the improved control reported in non-pregnant individuals. Insulin lispro is the only insulin analog to be systematically studied in pregnancy. At this time, the majority of evidence suggests that insulin lispro does not cross the placenta and does not have adverse maternal or fetal effects during pregnancy in women with diabetes. For women with gestational diabetes mellitus (GDM) and type 2 diabetes, which are characterized by insulin resistance and relatively decreased insulin secretion, treatment with oral hypoglycemic agents is generating much excitement. Most retrospective studies and the published clinical experience have failed to demonstrate an increased risk of neonatal hypoglycemia and other neonatal morbidities with glyburide or metformin. To date there has been only one randomized controlled trial utilizing glyburide, which found it to be safe and effective in the management of GDM. More intensive investigation regarding the safety and feasibility of oral agents in pregnancies complicated by type 2 diabetes is necessary.

Defined culture conditions of human embryonic stem cells

Human embryonic stem cells (hESCs) are pluripotent cells that have the potential to differentiate into any tissue in the human body; therefore, they are a valuable resource for regenerative medicine, drug screening, and developmental studies. However, the clinical application of hESCs is hampered by the difficulties of eliminating animal products in the culture medium and/or the complexity of conditions required to support hESC growth. We have developed a simple medium [termed hESC Cocktail (HESCO)] containing basic fibroblast growth factor, Wnt3a, April (a proliferation-inducing ligand)/BAFF (B cell-activating factor belonging to TNF), albumin, cholesterol, insulin, and transferrin, which is sufficient for hESC self-renewal and proliferation. Cells grown in HESCO were maintained in an undifferentiated state as determined by using six different stem cell markers, and their genomic integrity was confirmed by karyotyping. Cells cultured in HESCO readily form embryoid bodies in tissue culture and teratomas in mice. In both cases, the cells differentiated into each of the three cell lineages, ectoderm, endoderm, and mesoderm, indicating that they maintained their pluripotency. The use of a minimal medium sufficient for hESC growth is expected to greatly facilitate clinical application and developmental studies of hESCs.

Echocardiographic measurements in infants of diabetic mothers and macrosomic infants of nondiabetic mothers

AIM

To compare echocardiographic findings of infants of diabetic mothers (IDMs), macrosomic infants of nondiabetic mothers and healthy full term appropriate-for-gestational-age (AGA) infants.

METHODS

Included in this study were 83 infants, admitted to our Neonatology Unit. Thirty-three IDMs, including both macrosomic and nonmacrosomic, comprised Group A, 25 macrosomic infants of nondiabetic mothers comprised group B, and 25 healthy full term AGA infants comprised group C. Echocardiographic measurements were performed in the first three days after birth and compared by using one-way ANOVA, Post Hoc Tukey HSD and Student's t tests.

RESULTS

The left ventricular end-systolic/left ventricular end-diastolic diameter ratio of group A was significantly smaller than that of group C (P<0.05). The interventricular septum/posterior wall thickness ratios of groups A and B were greater than those of group C (P<0.05). The left ventricular mass index of group A was greater than those of groups B and C (P<0.05). The shortening fraction and ejection fraction of group A were increased in comparison to group C (P<0.05). When comparing the values of echocardiographic measurements of macrosomic IDMs (n=9) with nonmacrosomic ones (n=24), and infants of pregestational diabetic mothers (n=11) with those of gestational diabetes mothers (n=22), no statistical difference was found.

CONCLUSION

The present study suggests that underlying mechanisms common to both macrosomic infants of nondiabetic mothers and IDMs lead to less cardiac alterations in the macrosomic infants of nondiabetic mothers than in IDMs.

T-type Ca2+ channels are involved in high glucose-induced rat neonatal cardiomyocyte proliferation

Infants develop hypertrophic cardiomyopathy in approximately 30% of diabetic pregnancies. We have characterized the effects of glucose on voltage-gated T-type Ca2+ channels and intracellular free calcium concentration, [Ca2+]i in neonatal rat cardiomyocytes. We found that T-type Ca2+ channel current density increased significantly in primary culture neonatal cardiac myocytes that were treated with 25 mM glucose for 48 h when compared with those that were treated with 5 mM glucose. High-glucose treatment also caused a higher Ca2+ influx elicited by 50 mM KCl in the myocytes. KCl-induced Ca2+ influx was attenuated when nickel was present. Real-time PCR studies demonstrated that mRNA levels of both alpha1G (Ca(v)3.1) and alpha1H (Ca(v)3.2) T-type Ca2+ channels were elevated after high-glucose treatment. High-glucose also significantly increased ventricular cell proliferation as well as the proportion of cells in the S-phase of the cell cycle; both effects were reversed by nickel or mibefradil. These results indicate that high glucose causes a rise in [Ca2+]i in neonatal cardiac myocytes by a mechanism that is associated with the regulation of the T-type Ca2+ channel activity.

Modulation of eomes activity alters the size of the developing heart: implications for in utero cardiac gene therapy

Congenital heart disease is the most prevalent cause of infant morbidity and mortality in developed countries. The mechanisms responsible for many specific types of congenital cardiac malformations are strongly associated with gene abnormalities. However, at this time no strategies for gene therapy of the various congenital heart malformations have been investigated. In the present studies we focus on Eomesodermin (Eomes), a T-box transcription factor expressed in developing vertebrate mesoderm. Although Eomes is required for early mesodermal patterning and differentiation, the role of Eomes in cardiac development is unknown. In the present studies we demonstrate that Eomes is expressed in the developing heart, with a pronounced myocardial distribution in the Xenopus ventricle during late cardiac development. Using either a conditional dominant-interfering approach (GR-Eomes--engrailed) or an Eomes-activating approach (GR-Eomes-VP16) we demonstrate that manipulating Eomes activity during late cardiac development can either suppress ventricular development (GR-Eomes-enR) or increase ventricular myocardial size (GR-Eomes-VP16). Thus, a potential gene therapy approach for treating both congenital ventricular hypoplasia (e.g., the hypoplastic left heart syndrome) and hypertrophic cardiomyopathy is hypothetically implicit from the present results.

Mouse models of insulin resistance

Insulin resistance plays a key role in the pathogenesis of several human diseases, including diabetes, obesity, hypertension, and cardiovascular diseases. The predisposition to insulin resistance results from genetic and environmental factors. The search for gene variants that predispose to insulin resistance has been thwarted by its genetically heterogeneous pathogenesis. However, using techniques of targeted mutagenesis and transgenesis in rodents, investigators have developed mouse models to test critical hypotheses on the pathogenesis of insulin resistance. Moreover, experimental crosses among mutant mice have shed light onto the polygenic nature of the interactions underlying this complex metabolic condition.

Is There a Role for Oral Antihyperglycemics in Gestational Diabetes and Type 2 Diabetes during Pregnancy?

Diabetes mellitus is a heterogeneous disorder of glucose intolerance that is generally classified into the following categories: type 1 and type 2 diabetes and gestational diabetes (GDM). Currently, the number of pregnancies complicated by type 2 diabetes and GDM exceed those affected by type 1 diabetes. Numerous studies have established a direct relationship between maternal glycemic control and neonatal outcomes for all types of diabetes. Therefore, modern treatment protocols during pregnancy emphasize strict glycemic control by a combination of diet and medication. Traditionally, insulin therapy has been considered the gold standard for management because of its efficacy in achieving tight glucose control and the fact that it does not cross the placenta. Since GDM and type 2 diabetes are characterized by insulin resistance and relatively decreased insulin secretion, treatment with oral antihyperglycemic agents that target these defects is of potential interest. However, because of concerns regarding transplacental passage and, therefore, the possibility of fetal teratogenesis and prolonged neonatal hypoglycemia, these agents are not currently recommended in pregnancy. There are no randomized controlled trials on which to draw conclusions regarding the teratogenicity of these oral agents. However, most retrospective studies and the published clinical experience have not demonstrated an increased risk of malformed infants among women treated with oral antihyperglycemic agents. Rather, the data indicate that the increased risk for major congenital anomalies appears to be related to maternal glycemic control prior to and during conception. These studies and currently available data on the use of both metformin and sulfonylureas in pregnancy have also failed to demonstrate an increased risk of neonatal hypoglycemia and other neonatal morbidities. To date, there has only been one randomized controlled trial to test the effectiveness and safety of sulfonylurea therapy (glyburide [glibenclamide]) in the management of women with GDM. Both the insulin- and glyburide-treated women were able to achieve satisfactory glucose control and had similar perinatal outcomes. Glyburide was not detected in the cord serum of any infant in the glyburide group. In summary, based on the currently available data, it appears that glyburide could be safely and effectively utilized in the management of GDM. However, more intensive investigation regarding the safety and feasibility of oral agents in pregnancies complicated by type 2 diabetes is necessary. It is important to emphasize that it is the level of metabolic control achieved and not the mode of therapy that is crucial to improving outcomes in these pregnancies.

Insulin receptor knockout mice

To examine the role of the insulin receptor in fuel homeostasis, we and others have carried out genetic ablation studies in mice. Mice lacking insulin receptors are born with normal features, but develop early postnatal diabetes and die of ketoacidosis. In contrast, mice lacking insulin receptors in specific cell types as a result of conditional mutagenesis develop mild metabolic and reproductive abnormalities. These experiments have uncovered novel functions of insulin receptors in tissues such as brain and pancreatic beta-cells. Combined knockout studies of insulin and Igf1 receptors indicate that the insulin receptor also promotes embryonic growth. Experimental crosses of mice with insulin receptor haploinsufficiency have been instrumental to the genetic analysis of insulin action by enabling us to assign specific roles to different insulin receptor substrates and identify novel elements in insulin signaling.

Maternal hypoglycemia during pregnancy in type 1 diabetes: maternal and fetal consequences

There is strong evidence that the avoidance of hyperglycemia is essential inoptimizing pregnancy outcome in type 1 diabetes. The price to pay is a striking increase in severe hypoglycemia (SH), defined as episodes requiring help from another person. During type 1 diabetic pregnancy, occurrence rates of SH up to 15 times higher as in the intensively treated group of the Diabetes Control and Complications Trial (DCCT) are reported. Blood glucose (BG) treatment targets differ considerably between clinics; some authors advocate lower limits as low as 3.3 mmol/l. Improved glycemic control and/or recurrent hypoglycemia (i.e. BG <3.9 mmol/l) may result in impairment of glucose counterregulatory responses. Also, glucose counterregulation may be altered by pregnancy itself. Short-acting insulin analogs may help reduce hypoglycemia with preservation of good glycemic control, but their use during pregnancy has yet to be proven safe.Several clinical studies did not establish an association between maternal hypoglycemia and diabetic embryopathy. However, animal studies clearly indicate that hypoglycemia is potentially teratogenic during organogenesis. Increased rates of macrosomia continue to be observed despite near normal HbA(1c) levels. This may, at least in part, be the result of rebound hyperglycemia elicited by hypoglycemia. Exposure to hypoglycemia in utero may have long-term effects on offspring including neuropsychological defects. It is yet unclear to what extent the benefits of tight glycemic control balance with the increased risk of (severe) hypoglycemia during type 1 diabetic pregnancy. Efforts must be made to avoid low BG, i.e. <3.9 mmol/l, when tightening glycemic control.

Distinct and overlapping functions of insulin and IGF-I receptors

Targeted gene mutations have established distinct, yet overlapping, developmental roles for receptors of the insulin/IGF family. IGF-I receptor mediates IGF-I and IGF-II action on prenatal growth and IGF-I action on postnatal growth. Insulin receptor mediates prenatal growth in response to IGF-II and postnatal metabolism in response to insulin. In rodents, unlike humans, insulin does not participate in embryonic growth until late gestation. The ability of the insulin receptor to act as a bona fide IGF-II-dependent growth promoter is underscored by its rescue of double knockout Igf1r/Igf2r mice. Thus, IGF-II is a true bifunctional ligand that is able to stimulate both insulin and IGF-I receptor signaling, although with different potencies. In contrast, the IGF-II/cation-independent mannose-6-phosphate receptor regulates IGF-II clearance. The growth retardation of mice lacking IGF-I and/or insulin receptors is due to reduced cell number, resulting from decreased proliferation. Evidence from genetically engineered mice does not support the view that insulin and IGF receptors promote cellular differentiation in vivo or that they are required for early embryonic development. The phenotypes of insulin receptor gene mutations in humans and in mice indicate important differences between the developmental roles of insulin and its receptor in the two species.

Pancreatic disorders in the newborn

Except for the hyperinsulinism associated with the infant of a diabetic mother (accounting for about 5 percent of NICU admissions annually), pancreatic disorders of the newborn are rare. Congenital anomalies (such as annular pancreas) and endocrine disorders (such as hyperinsulinism of nesidioblastosis or hyperglycemia of neonatal diabetes mellitus) present many challenges to the personnel caring for these infants and their families. The potential mortality and morbidity of these disorders make it imperative for nurses and nurse practitioners working with infants to recognize and understand pancreatic dysfunction so that appropriate and timely intervention can prevent complications of brain injury and developmental delay. The home care needs of these infants and the extensive teaching needs of their parents require skilled nursing care to ensure a safe discharge.

Detection of placental growth hormone variant and chorionic somatomammotropin-L RNA expression in normal and diabetic pregnancy by reverse transcriptase-polymerase chain reaction

Diabetes is a common complication encountered during pregnancy. Earlier studies indicated that diabetic placentas bear morphological alterations consistent with modified placental differentiation, including alterations in the villous cellular content, structure, and total surface. Limited data associating the diabetic status with the expression of terminal placental differentiation markers are available. The human growth hormone/chorionic somatomammotropin (hGH/CS) family consists of five genes, one of which (GH-N) is expressed efficiently in pituitary while the other four (CS-A, B, L, and hGH-V) are expressed in placenta and represent ultimate placental differentiation markers. We developed and applied a sensitive RT-PCR method coupled with diagnostic restriction digestion to determine the relative levels of the hGH/CS family in normal pregnancies and examine whether their mRNA expression pattern is altered in pregnancies complicated by diabetes. We show that relative hCS-L content changes during placental development. Specifically, normal term placentas express higher relative levels of hCS-L, lower relative hGH-V levels and a 70-fold lower hGH-V/CS-L mRNA ratio compared to early placentas. Also, many term placentas from diabetic pregnancies express lower relative levels of hCS-L mRNA and a much higher hGH-V/CS-L mRNA ratio compared to normal term placenta, resembling more an early placenta pattern of expression. Thus, our study suggests that the expression of terminal placental differentiation markers, such as the hGH/CS genes, is altered in term placentas from these diabetics reflecting either impaired placental differentiation or post-differentiation impairment of normal placental function.

Radiographic evaluation of the neonate with congenital heart disease

Remarkable advances in pediatric cardiology have been spurred by the explosion of technologies both in interventional and surgical techniques and the ability to manipulate the genome of experimental animals. After a brief discussion concerning the striking advances in the molecular understanding of congenital heart disease, this article focuses on clues to the diagnosis of congenital heart disease and on chest radiography and common, specific lesions of the neonate such as hypoplastic left heart, transposition of the great vessels, and severe tetralogy of Fallot. The impact of treatment protocols involving interventional cardiology in the neonate also are discussed.

Effect of maternal diabetes on the fetal exocrine pancreas

To test the hypothesis that fetal pancreatic exocrine and endocrine function are stimulated in parallel in the diabetic pregnancy, 68 mothers with gestational and pregestational diabetes who underwent amniocenteses after 34 weeks' for the evaluation of fetal lung maturity were enrolled. Amniotic fluid specimens were analyzed for C-peptide and trypsin content. Amniotic fluid specimens were obtained from 92 non-diabetic women undergoing amniocenteses for lung maturity, preterm labor, or premature rupture of membranes. Groups were compared using the Wilcoxon rank-sum test, Kruskal Wallis rank sum test, and Spearman's rank correlation test. C-peptide amniotic fluid concentrations were significantly greater in diabetics (median 0.6 ng/ml) than non-diabetics (median 0.4 ng/ml, P= 0.0001), in pregestational (median 0.6 ng/ml) vs. gestational diabetics (median 0.4 ng/ml, P = 0.006), and greater in proportion to severity of disease according to diabetic class (A1 = 0.4 ng/ml, A2 = 0.55 ng/ml, B = 0.6 ng/ml, C = 0.7 ng/ml, D = 0.85 ng/ml, P = 0.04). No significant differences were detected in amniotic fluid trypsin between the diabetic and non-diabetic or the gestational and non-gestational diabetic groups. There was no correlation between C-peptide and trypsin within the diabetic groups. Stimulation of the exocrine and endocrine pancreas does not occur in parallel in the fetus of the diabetic mother. Although originating as a single organ, pancreatic exocrine and endocrine functions are distinct in both physiologic and pathologic conditions.