Carmen Tudela

The c-Myc-regulated microRNA-17~92 (miR-17~92) and miR-106a~363 clusters target hCYP19A1 and hGCM1 to inhibit human trophoblast differentiation.

ABSTRACT Mononuclear cytotrophoblasts of the human placenta proliferate rapidly, subsequently fuse, and differentiate to form multinucleated syncytiotrophoblast with induction of aromatase (hCYP19A1) and chorionic gonadotropin (hCGβ) expression. Using microarray analysis, we identified members of the miR-17∼92 cluster and its paralogs, miR-106a∼363 and miR-106b∼25, that are significantly downregulated upon syncytiotrophoblast differentiation. Interestingly, miR-19b and miR-106a directly targeted hCYP19A1 expression, while miR-19b also targeted human GCM1 (hGCM1), a transcription factor critical for mouse labyrinthine trophoblast development. Overexpression of these microRNAs (miRNAs) impaired syncytiotrophoblast differentiation. hGCM1 knockdown decreased hCYP19A1 and hCGβ expression, substantiating its important role in human trophoblast differentiation. Expression of the c-Myc proto-oncogene was increased in proliferating cytotrophoblasts compared to that in differentiated syncytiotrophoblast. Moreover, c-Myc overexpression upregulated miR-17∼92 and inhibited hCYP19A1 and hCGβ expression. Binding of endogenous c-Myc to genomic regions upstream of the miR-17∼92 and miR-106a∼363 clusters in cytotrophoblasts dramatically decreased upon syncytiotrophoblast differentiation. Intriguingly, we observed higher levels of miR-106a and -19b and lower aromatase and hGCM1 expression in placentas from preeclamptic women than in placentas from gestation-matched normotensive women. Our findings reveal that c-Myc-regulated members of the miR-17∼92 and miR-106a∼363 clusters inhibit trophoblast differentiation by repressing hGCM1 and hCYP19A1 and suggest that aberrant regulation of these miRNAs may contribute to the pathogenesis of preeclampsia.

Relationship of subclinical thyroid disease to the incidence of gestational diabetes.

OBJECTIVE: To estimate if there is a relationship between subclinical thyroid disease and gestational diabetes. METHODS: Between November 2000 and April 2003, serum thyrotropin screening was performed on all women who presented for prenatal care. Women identified with abnormal thyrotropin had a serum free thyroxine reflexively determined. Those women with abnormal serum free thyroxine values were referred for further evaluation and excluded from further analysis. For this analysis, normal thyrotropin values were those between the 2.5th and 97.5th percentiles (0.03–4.13 milliunits/L) not corrected for gestational age and serum free thyroxine were considered normal if they ranged from 0.9 to 2.0 mg/dL. Women with an elevated serum thyrotropin but a normal serum free thyroxine were designated to have subclinical hypothyroidism and those with a low thyrotropin and a normal serum free thyroxine level were designated to have subclinical hyperthyroidism. Euthyroid women had both normal thyrotropin and normal serum free thyroxine values. The incidence of gestational diabetes was compared among these three groups. RESULTS: Of the 24,883 women included in the study, 23,771 (95.5%) were euthyroid, 584 (2.3%) had subclinical hyperthyroidism, and 528 (2%) had subclinical hypothyroidism. The likelihood of gestational diabetes increased with thyrotropin level (P=.002). For example, when a pregnant Hispanic woman of average age and weight was used, the predicted percent of gestational diabetes increased from 1.9% to 4.9% as thyrotropin increased from 0.001 to 10 milliunits/L (P=.001). CONCLUSION: The risk of developing gestational diabetes increases with thyrotropin level. This supports a relationship between subclinical hypothyroidism and diabetes diagnosed during pregnancy. LEVEL OF EVIDENCE: III

Glyburide in Women with Mild Gestational Diabetes: A Randomized Controlled Trial

OBJECTIVE: To evaluate whether the addition of glyburide to diet therapy modifies pregnancy outcomes in women with mild gestational diabetes. METHODS: Women with at least two abnormal values on a 3-hour, 100-g oral glucose tolerance test according to National Diabetes Data Group criteria and fasting values less than 105 mg/dL between 24 and 30 weeks of gestation were randomized to blinded glyburide or placebo study drug. All women were placed on a 35-kcal/kg diet and recorded four times daily capillary glucose measurements. The study drug was titrated based on weekly maternal capillary glucose values with targets of less than 95 mg/dL (5.3 mmol/L) and 120 mg/dL (6.7 mmol/L) for fasting and 2-hour postprandial glucose measurements, respectively. The primary study outcome was a 200-g birth weight decrement in neonates of women treated with glyburide. The sample size estimate for this outcome was 334 total randomized women with a one-to-one allocation. RESULTS: A total of 395 women were enrolled at a single center between September 2008 and October 2012. Women treated with glyburide had a significantly greater decline in fasting glucose values over the course of therapy. However, there was no difference in the primary study outcome. Specifically, the mean birth weight was 33 g lower in the group treated with glyburide (P=.52). Although not powered to examine all outcomes associated with gestational diabetes, treatment with glyburide did not affect need for operative delivery, shoulder dystocia, clavicular fracture, Erbs palsy, or neonatal hypoglycemia. Four women in each group required insulin. CONCLUSION: The addition of glyburide to diet therapy significantly improved maternal glycemic control over time when compared with placebo. However, adding glyburide to diet did not decrease birth weight or improve maternal or neonatal outcomes in women with mild gestational diabetes. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00744965. LEVEL OF EVIDENCE: I

Intrapartum evidence of early-onset group B streptococcus.

OBJECTIVE: To estimate if neonates with early-onset group B streptococcus (GBS) sepsis have clinical evidence of fetal infection during labor or at delivery. METHODS: Retrospective cohort study of all neonates diagnosed with GBS sepsis by culture and clinical findings within the first 72 hours of life from January 1, 2000, through December 31, 2008, at Parkland Health and Hospital System. Medical records were reviewed and maternal, neonatal, and delivery data were ascertained. These neonates then were compared with all neonates delivered during the same time period. RESULTS: During the study period, 143,384 live-born neonates were delivered at our institution; 94 were diagnosed with early-onset GBS sepsis. The majority of these neonates (n=93) were diagnosed with early-onset GBS within the first hour of life. Neonates with early-onset GBS sepsis had a significant increase in preterm delivery, cesarean delivery (total and for fetal distress), 1- and 5-minute Apgar scores of 3 or lower, umbilical cord pH less than 7.0, and a base deficit of 12 mmol/L or higher. In addition, nulliparity differed between those with early-onset GBS and those without (74% compared with 33%, P<.001) as did chorioamnionitis rates (62% compared with 8%, P<.001). CONCLUSION: We believe that these findings are compelling evidence that fetuses with early-onset GBS may have signs of sepsis peripartum. We hypothesize that these data support the concept that early-onset GBS represents a spectrum of infection that often precedes birth. LEVEL OF EVIDENCE: II

Effect of maternal body mass index on serum magnesium levels given for seizure prophylaxis.

OBJECTIVE: To estimate the effect of body mass index (BMI) on magnesium levels for eclampsia prophylaxis. METHODS: This is a retrospective study from 2004 to 2011, examining magnesium levels in women receiving seizure prophylaxis. Women received 6 g and then 2 g/h. Women had 4-hour and 12-hour levels drawn. Levels were considered subtherapeutic at less than 4.9 mg/dL, therapeutic from 4.9 to 8.4 mg/dL, and supratherapeutic at 8.5 mg/dL or more. If the 4-hour value was not therapeutic, the dose was adjusted and a 12-hour level was drawn. Levels at 4 and 12 hours were compared among the women with different BMI classifications and clinical characteristics. RESULTS: During the study period,106,265 women delivered, and 7,799 (7.4%) had preeclampsia diagnosed and received magnesium sulfate for seizure prophylaxis. A total of 5,304 (68%) of these women had a recorded BMI. At 4 hours, 2,698 (51%) were subtherapeutic. These women were more likely to be older, parous, undergo cesarean delivery, have a higher systolic blood pressure, and have central nervous system manifestations. At 12 hours, 2,342 (90%) of therapeutic women remained therapeutic, and 5% became subtherapeutic (n=118) or supratherapeutic (n=140). Using logistic regression, we were able to predict being subtherapeutic in women with greater BMI and to predict being supratherapeutic if women had labor longer than 12 hours and worsening severity of preeclampsia. CONCLUSION: Women receiving seizure prophylaxis with a BMI of more than 30 may benefit from routine serum magnesium evaluation 4 hours after the loading dose. LEVEL OF EVIDENCE: III

Estrogen-Related Receptor γ Serves a Role in Blood Pressure Homeostasis During Pregnancy

Persistent hypoxia caused by shallow trophoblast invasion and poor placental perfusion may underlie the pathophysiology of preeclampsia, a leading cause of maternal and neonatal morbidity and mortality. Previously, we found that estrogen-related receptor γ (ERRγ) serves a critical and O2-dependent role in differentiation of human trophoblasts in culture and expression of tissue kallikrein and voltage-gated K(+) channels. In this study, we surprisingly observed that ERRγ expression was significantly increased in placentas from preeclamptic women compared with that in gestation-matched normotensive women. To further investigate a functional role for ERRγ during pregnancy, we analyzed ERRγ-deficient mice. Maternal systolic blood pressure was significantly reduced in pregnant ERRγ(+/-) females bred to ERRγ(+/-) males compared with that in wild-type (WT) mice and was markedly up-regulated by treatment of WT pregnant mice with the ERRγ agonist DY131. Placentas of ERRγ(+/-) mice manifested increased vascular endothelial growth factor A expression compared with that in WT mice. Notably, circulating levels of the antiangiogenic factor, soluble fms-like tyrosine kinase-1, were significantly reduced in ERRγ(+/-) pregnant mice as was serum aldosterone. These effects were associated with a decrease in maternal adrenal Cyp11b1 (steroid 11β-hydroxylase) and Cyp11b2 (aldosterone synthase) expression. In contrast, adrenal Cyp11b1 and Cyp11b2 mRNA were increased in pregnant WT mice treated with DY131. Moreover, chromatin immunoprecipitation and luciferase reporter assays identified Cyp11b2 as a transcriptional target of ERRγ. Collectively, these findings reveal a potential role of ERRγ in maternal blood pressure homeostasis during pregnancy and suggest that aberrant ERRγ expression may contribute to the pathogenesis of preeclampsia.