Adrenocortical imprint in the fetus of a diabetic gestation

Sonographic Evaluation of Fetal Adrenal Gland in Gestational Diabetes: Relation to Fetal Growth and Maternal Biochemical Markers

OBJECTIVES

To relate measurements and volume of the fetal adrenal gland in third trimester ultrasound in diabetic pregnancies (1) to birth weight; (2) to other sonographic markers of diabetic fetopathy (expected fetal weight, sectional area, and fractional volume in fetal limbs); and (3) to maternal biochemical markers of diabetes (HbA1c, leptin).

METHODS

Fetal adrenal gland measurements were obtained between 32 and 34 weeks. The gland length, width, depth, and volume (by Virtual Organ Computer-Aided Analysis [VOCAL]) were measured for total gland and fetal zone. Fetal total and fat sectional area and fractional volume were obtained in arm and thigh. A maternal blood sample was obtained. Univariate and multivariate models were used to assess the associations.

RESULTS

Thirty-nine diabetic pregnancies were included. Birth weight related significantly to total and fetal zone adrenal depth, and total adrenal volume in third trimester. Total adrenal length and corrected adrenal gland volume also showed a significant correlation to birth weight percentile in univariate and multivariate models. Total adrenal volume associated significantly to total and fat areas and volumes in fetal limbs. Both maternal leptin and HbA1c levels found a significant positive relation to fetal total adrenal volume and corrected adrenal gland volume. Total adrenal gland volume showed a significant association to maternal HbA1c level in multivariate model.

CONCLUSIONS

An enlargement of the fetal adrenal gland may be observed in gestational diabetes, not only related to birth weight, but also to distinctive features of diabetic pregnancies, such as fat tissue fetal deposits or maternal biochemical markers.

Modulation of cholesterol transport by insulin-treated gestational diabetes mellitus in human full-term placenta

Gestational diabetes mellitus (GDM) is a common complication of pregnancy that is characterized by glucose intolerance, leads to dyslipidemia, and is aggravated by obesity. Cholesterol is taken up by the placenta as part of lipoproteins through the scavenger receptor class B type I receptor (SRBI), low-density lipoprotein receptor (LDLR), and very low density lipoprotein receptor (VLDLR), and its efflux is then mediated by ABCA1 and ABCG1. PCSK9 is involved in the degradation of LDLR and VLDLR. The goal of this study was to evaluate the impact of GDM and prepregnancy body mass index (BMI) on cholesterol transport through the modulation of the expression of several key players. Human full-term placenta, maternal, and venous cord blood samples were obtained at delivery from normal-weight women without GDM (n = 10), normal-weight women with GDM (n = 6), and overweight/obese women with GDM (n = 6). Lipids (total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, free fatty acids, apolipoprotein A1, apolipoprotein B100) levels were evaluated in blood samples. Messenger RNA and protein expression levels (LDLR, VLDLR, SRBI, ABCA1, ABCG1, proprotein convertase subtilisin/kexin type 9, liver x receptors, peroxisome proliferator-activated receptors) were assessed in human full-term placenta, respectively, by real-time RT-PCR and Western blots. Lipoprotein lipase activity was evaluated using a commercial kit on tissue homogenates. Overall, our study demonstrates that GDM affects the maternal and neonatal lipid profiles as well as different key players of placental cholesterol transfer from the maternal to the fetal circulation, depending on the maternal BMI. These changes could affect the fetal metabolism and predispose the fetus to future metabolic diseases.

Diabetic pregnancy in rats leads to impaired glucose metabolism in offspring involving tissue-specific dysregulation of 11beta-hydroxysteroid dehydrogenase type 1 expression

Population-based studies have shown that the offspring of diabetic mothers have an increased risk of developing obesity, insulin resistance, type 2 diabetes and hypertension in later life. To investigate mechanism for the high incidence of metabolic diseases in the offspring of diabetic mothers, we focused on the tissue-specific glucocorticoid regulation by 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) and studied offspring born to streptozotocin-induced diabetic rats. The body weights of newborn rats from diabetic mothers were heavier than those from control mothers. Offspring born to diabetic mothers demonstrated insulin resistance and mild glucose intolerance after glucose loading at 10 weeks and showed significantly increased 11beta-HSD1 mRNA and enzyme activity in adipose tissue at 12 weeks of age without obvious obesity. Hepatic 11beta-HSD1 mRNA was also elevated. We propose that the 11beta-HSD1 in adipose tissue and liver may play a key role in the development of metabolic syndrome in the offspring of diabetic mothers. Tissue-specific glucocorticoid dysregulation provides a candidate mechanism for the high incidence of metabolic diseases in the offspring of diabetic mothers. Therefore early analyses before apparent obesity are needed to elucidate the molecular mechanisms that may be programmed during the fetal period.

Streptozotocin-induced diabetes in the pregnant rat reduces 11 beta-hydroxysteroid dehydrogenase type 2 expression in placenta and fetal kidney

Several epidemiological and animal studies have shown that the offsprings of diabetic mothers have higher incidences of glucose intolerance, obesity, insulin resistance, and hypertension in later life. It is well known that glucocorticoid metabolism plays a crucial role on several adult disease originated from fetal environment. The aim of this study was to investigate the relation between diabetic pregnancy and glucocorticoid metabolism of both mother and fetus, focusing on the 11 beta-hydroxysteroid dehydrogenase (11beta-HSD) type 2. A model of diabetic pregnancy was made by intravenous injection of streptozotocin (35 mg/kg body weight) to Sprague-Dawley rats, and blood and tissue samples were collected on day 20 of pregnancy. In the diabetic group, expression of 11 beta-hydroxysteroid dehydrogenase type 2 in placentas and fetal kidneys was decreased remarkably. Corticosterone levels of diabetic mothers were lower than those of control rats. Despite the differences in maternal corticosterone levels, fetal levels of corticosterone did not differ between the groups. Our results lend support to the concept that diabetic pregnancy imprints glucocorticoid regulation in these fetuses, which may contribute to their increased incidence of higher blood pressure as adults.