Steroid production and excretion by the pregnant mouse, particularly in relation to pregnancies with fetuses deficient in Delta7-sterol reductase (Dhcr7), the enzyme associated with Smith-Lemli-Opitz syndrome

Continuous glucose monitoring during pregnancy in healthy mice

During pregnancy, metabolic adaptations occur to maintain the balance between maternal and foetal growth, including increased insulin secretion and decreased insulin sensitivity. When the body fails to adjust, gestational diabetes mellitus develops. To gain insight in the pregnancy-induced adaptations, we applied continuous glucose monitoring via telemetric transmitters. We show that continuous glucose monitoring in conscious, non-stressed, freely moving mice throughout the full pregnancy is feasible, accurate and safe. We show that healthy mice during a full pregnancy develop adaptations in glucose homeostasis reminiscent of those in pregnant women. Furthermore, continuous glucose monitoring allows the complete analysis of all aspects of glucose excursions associated with spontaneous feeding episodes, and the thorough analysis of glycaemic variability. In conclusion, continuous glucose monitoring allows a detailed description of the glycaemic status during pregnancy, which will help to unravel specific mechanisms for gestational diabetes mellitus.

Molecular mechanisms of estrogen action in female genital tract development

The development of the female reproductive tract can be divided into three parts consisting of Müllerian duct organogenesis, pre-sexual maturation organ development, and post-sexual maturation hormonal regulation. In primates, Müllerian duct organogenesis proceeds in an estrogen independent fashion based on transcriptional pathways that are suppressed in males by the presence of AMH and SRY. However, clinical experience indicates that exposure to xenoestrogens such as diethylstilbestrol (DES) during critical periods including late organogenesis and pre-sexual maturational development can have substantial effects on uterine morphology, and confer increased risk of disease states later in life. Recent evidence has demonstrated that these effects are in part due to epigenetic regulation of gene expression, both in the form of aberrant CpG methylation, and accompanying histone modifications. While xenoestrogens and selective estrogen receptor modulators (SERMS) both can induce non-canonical binding confirmations in estrogen receptors, the primate specific fetal estrogens Estriol and Estetrol may act in a similar fashion to alter gene expression through tissue specific epigenetic modulation.

Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive, multiple congenital malformation and intellectual disability syndrome, with clinical characteristics that encompass a wide spectrum and great variability. Elucidation of the biochemical and genetic basis for SLOS, specifically understanding SLOS as a cholesterol deficiency syndrome caused by mutation in DHCR7, opened up enormous possibilities for therapeutic intervention. When cholesterol was discovered to be the activator of sonic hedgehog, cholesterol deficiency with inactivation of this developmental patterning gene was thought to be the cause of SLOS malformations, yet this explanation is overly simplistic. Despite these important research breakthroughs, there is no proven treatment for SLOS. Better animal models are needed to allow potential treatment testing and the study of disease pathophysiology, which is incompletely understood. Creation of human cellular models, especially models of brain cells, would be useful, and in vivo human studies are also essential. Biomarker development will be crucial in facilitating clinical trials in this rare condition, because the clinical phenotype can change over many years. Additional research in these and other areas is critical if we are to make headway towards ameliorating the effects of this devastating condition.