Jae Hyug Yang

Effective Prediction of Preeclampsia by a Combined Ratio of Angiogenesis-Related Factors

OBJECTIVE: Imbalance between angiogenesis-related factors is closely related to the development of preeclampsia. The objective was to estimate the most effective and accurate predictive biomarker among levels and ratios of angiogenesis-related factors, including soluble fms-like tyrosine kinase 1 (sFlt-1), soluble endoglin, placental growth factor (PlGF), and transforming growth factor-&bgr;1 (TGF-&bgr;1), in women who subsequently developed preeclampsia. METHODS: A nested cohort study was conducted to estimate the levels of sFlt-1, soluble endoglin, PlGF, and TGF-&bgr;1 in plasma collected in the second trimester from 40 women who subsequently developed preeclampsia and 100 contemporaneous normotensive women. RESULTS: Levels of sFlt-1 and soluble endoglin were significantly higher in women with preeclampsia than in normotensive women, whereas levels of PlGF and TGF-&bgr;1 were lower (P<.001). In women with preeclampsia, sFlt-1/PlGF, soluble endoglin/TGF-&bgr;1, and the combined ratio of (sFlt-1+soluble endoglin)/(PlGF+TGF-&bgr;1) were significantly higher than in normotensive women (P<.001) and even greater in severe preeclampsia with preterm delivery compared with mild preeclampsia with term delivery (P<.05). At equivalent sensitivity (85%), the false-positive rate was 45% for sFlt-1, 41% for soluble endoglin, 33% for sFlt-1/PlGF, 21% for soluble endoglin/TGF-&bgr;1, and 10% for the combined ratio. After adjusting for potential confounding factors, the risks for developing preeclampsia were as follows: odds ratio (OR) 6.9 [95% confidence interval 2.3-20.7] for sFlt-1 level, 7.1 [2.3-21.7] for soluble endoglin level, 6.8 [2.4-19.4] for sFlt-1/PlGF, 38.8 [9.8-154.3] for soluble endoglin/TGF-&bgr;1, and 74.8 [17.6-316.7] for the combined ratio. CONCLUSION: The combined ratio of angiogenesis-related factors showed the lowest false-positive rate and the highest OR for prediction of preeclampsia, indicating that it may provide more effective prediction of development of preeclampsia. LEVEL OF EVIDENCE: II

Differentiation of endothelial cells from human umbilical cord blood AC133-CD14+ cells.

Endothelial progenitor cells (EPCs) participate in neovascularization and are consistent with postnatal vasculogenesis. In vitro, they differentiate into endothelial cells (ECs). Prior reports have suggested that circulating human AC133+ cells have the capacity to differentiate into ECs as progenitor cells. However, recent studies have demonstrated that circulating CD34−CD14+ cells also have EPC-like properties in vitro and in vivo. We tested whether AC133−CD14+ cells from human umbilical cord blood (HUCB) have the potential to differentiate into ECs. The AC133−CD14+ cells were isolated from HUCB by magnetic bead selection and cultured on fibronectin-coated six-well trays in M199 medium supplemented with fetal bovine serum (FBS), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and insulin growth factor (IGF-1). The AC133−CD14+ cells adhered slightly within 1 day of culture and subsequently underwent a distinct process of morphological transformation to spindle-shaped cells that sprouted from the edge of the cell clusters. After 14 days, the cells formed cord- and tubular-like structures. The AC133−CD14+ cells showed a strong increase in the endothelial marker P1H12 over time, whereas CD14 decreased, and CD45 did not change, respectively. In addition, the cells expressed endothelial markers von Willebrand’s factor (vWF), platelet/endothelial cell adhesion molecule-1 (PECAM-1), vascular endothelial growth factor receptor-1 (VEGFR-1)/Flt-1, VEGFR-2/Flk-1, eNOS, and VE-cadherin, but did not express Tie-2 after 7 days of culture. The present data indicate that AC133−CD14+ cells from HUCB are able to develop endothelial phenotype with expression of endothelial-specific surface markers and even form cord- and tubular-like structures in vitro as progenitor cells.

Menin mediates epigenetic regulation via histone H3 lysine 9 methylation

Menin, encoded by the multiple endocrine neoplasia type 1 (MEN1) gene, is a tumor suppressor that leads to multiple endocrine tumors upon loss of its function. Menin functions as a transcriptional activator by tethering MLL complex to mediate histone H3 K4 methylation. It also functions as a repressor. However, the molecular mechanism of how menin contributes to the opposite outcome in gene expression is largely unknown. Here, we investigated the role of menin in the epigenetic regulation of transcription mediated by histone covalent modification. We show that the global methylation level of histone H3 K9, as well as H3 K4, was decreased in Men1−/− MEF cells. Consistently, menin was able to interact with the suppressor of variegation 3–9 homolog family protein, SUV39H1, to mediate H3 K9 methylation. This interaction decreased when patient-derived MEN1 mutation was introduced into the SUV39H1-interaction domain. We show that menin mediated different chromatin changes depending on target genes. Chromatin immunoprecipitation studies showed that menin directly associated with the GBX2 promoter and menin-dependent recruitment of SUV39H1 was essential for chromatin remodeling and transcriptional regulation. These results provide a molecular basis of how menin functions as a transcriptional repressor and suggest that menin-dependent integration of H3 K9 methylation might play an important role in preventing tumors.

Maternal Serum Levels of VCAM-1, ICAM-1 and E-selectin in Preeclampsia

Endothelial dysfunction is thought to be a central pathogenic feature in preeclampsia on the basis of elevated adhesion molecules. The aim of the present study was to compare the levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), intercellular adhesion molecule-1 (sICAM-1) and E-selectin (sE-selectin) in sera of normal and preeclamptic pregnancies. We studied the serum levels of sVCAM-1, sICAM-1 and sE-selectin in normal pregnant women (n=63), mild preeclampsia (n=33) and severe preeclampsia (n=82). Concentrations of soluble adhesion molecules were determined with enzyme-linked immunoassay (ELISA). Serum concentrations of sVCAM-1 were significantly higher in both mild (p=0.004) and severe preeclampsia (p=0.000) than normal pregnancy. There were also significant differences in sVCAM-1 levels between mild and severe preeclampsia (p=0.002). sICAM-1 levels of severe preeclampsia were statistically different from those of normal pregnancy (p=0.038). Levels of sE-selectin were elevated in both mild (p=0.011) and severe preeclampsia (p=0.000) compared to normal pregnancy, but no statistical difference between the mild and severe preeclampsia (p=0.345). These results suggest that all three soluble adhesion molecules are increased in severe preeclampsia, and sVCAM-1 among them may be useful in predicting the severity of preeclampsia.

Genetic polymorphism of catechol-O-methyltransferase and cytochrome P450c17 in preeclampsia.

Objective Catechol-O-methyltransferase (COMT) and cytochrome P450c17α (CYP17A1) are key enzymes involved in the metabolism of steroid hormones; genetic polymorphisms in these genes affect enzyme activity. Recently, functional polymorphisms in the COMT and CYP17A1 genes have been suggested as a susceptible marker for intrauterine fetal growth restriction, a typical complication of preeclampsia. Moreover, a close association between COMT and preeclampsia was reported. We therefore investigated the relationships between COMT and CYP17A1 polymorphisms and the risk of preeclampsia. Methods A total of 164 preeclamptic women and 182 normotensive women were enrolled. COMT (Val158Met) and CYP17A1 (-34T/C) polymorphisms were genotyped by quantitative fluorescent-polymerase chain reaction. Multiple logistic regression analysis was used to estimate the risks of preeclampsia according to genotypes. Results The adjusted odds ratios (adjOR) for the risks of preeclampsia, severe preeclampsia and preeclampsia for small-for-gestational-age (SGA) infants were 1.97 [95% confidence interval (CI): 1.02–3.83], 3.29 (95% CI: 1.60–6.77), and 4.05 (95% CI: 1.78–9.22), respectively, in women homozygous for the variant COMT allele. No significant differences were observed between the two groups with respect to CYP17A1 polymorphisms, indicating that variants of this gene have no effects on preeclampsia. The highest risks of preeclampsia were found among women with homozygous variant genotypes of both genes [adjOR (95% CI): 4.58 (1.92–22.81)]. Moreover, the adjOR for preeclamptic complications in those women was 5.09 (95% CI: 1.93–27.88) for severe preeclampsia and 15.65 (95% CI: 3.19–76.82) for SGA preeclampsia. Conclusion These findings suggest that homozygosity for the variant allele of the maternal COMT gene may increase susceptibility to preeclampsia.

The Distribution of Fetal Nuchal Translucency Thickness in Normal Korean Fetuses

The aim of present study was to establish normative data for the distribution of nuchal translucency (NT) thickness in normal Korean fetuses. The data were collected from pregnant women with singleton pregnancies in whom fetal ultrasound was performed and the fetal NT thickness was measured between 11 and 14 weeks of gestation. Among them, a total of 2,577 fetuses with a known normal outcome were included in this study. The distribution of multiple of median (MoM) values of the NT thickness with crown-rump length (CRL) in 10-mm intervals and the 95th percentile of MoM were calculated with the linear regression method. The present study showed that NT measurements increase with increasing CRL and a false positive rate increases with increasing gestational age. Therefore, a fixed cut-off point through the first trimester was not appropriate and each NT measurement should be examined according to the gestational age. The present study offers normative data of the fetal NT thickness in a Korean population, which can be used as reference for screening chromosomal aberrations or other congenital abnormalities in the first trimester.

A Multi-center Study for Birth Defect Monitoring Systems in Korea

The aim of this study was to establish a multi-center birth defects monitoring system to evaluate the prevalence and the serial occurrence of birth defects in Korea. Ten medical centers participated in this program. A trained nurse collected relevant records from delivery units and pediatric clinics in participating hospitals on a monthly basis. We observed 1,537 cases of birth defects among 86,622 deliveries, which included live births and stillbirths. The prevalence of birth defects was 1.8%, and the sex distribution of the birth defect cases was 55.2% male and 41.6% female. The highest proportion of birth defects was in the cardiovascular system (17.5%), followed by birth defects involving in the genitourinary system (15.6%). Chromosomal anomalies were detected 30.0 per 10,000 births. Of these chromosomal anomalies, Down syndrome was most frequently observed. This study led to an establishment of a multi-center active monitoring system for birth defects. To better understand the serial occurrence of birth defects in Korea, it is necessary to increase the number of participating hospitals and to launch on a nation-wide multi-center study.

Perinatal Outcome in Twin Pregnancies Complicated by Gestational Diabetes Mellitus: A Comparative Study

The purpose of this study is to compare perinatal outcomes of twin pregnancies complicated by gestational diabetes (GDM) with those unaffected by GDM. A total of 1,154 twin pregnancies who delivered at Cheil General Hospital, between January 1998 and December 2002 were recruited to participate in a retrospective analysis. Out of these twin pregnancies, 37 women were had GDM. Four pregnancies exposed to GDM were excluded due to the loss of medical records; therefore 33 twin pregnancies exposed to GDM were enrolled. We matched the GDM pregnancies with pregnancies unaffected by GDM in a 1:2 ratio; therefore there were 33 GDM/66 without GDM who delivered during the study period. Our findings show that there were no significant differences including birth weight, Apgar score, respiratory distress syndrome, meconium aspiration pneumonia, transient tachypnea of new born, hyperbilirubinemia, hypoglycemia, hypocalcemia and congenital anomalies. Therefore, well controlled GDM may not increase perinatal complications in twin pregnancies. Careful pregnancy management and fetal surveillance in twin pregnancies is important to decrease perinatal complications and maintain a sound pregnancy and healthy offspring.

Neonatal brain damage following prolonged latency after preterm premature rupture of membranes.

This study evaluated the risk of brain damage in neonates delivered at <34 weeks following a prolonged latency after preterm premature rupture of membranes (pPROM). The medical records of 77 singletons delivered at <34 weeks with pPROM and 66 singletons delivered at <34 weeks with preterm labor and intact membranes were reviewed. Latency was divided into four intervals: ≤24, >24-≤72, >72-≤168 hr, and >1 week. Outcomes in the longer three intervals were compared with those in neonates delivered at ≤24 hr after pPROM. The documented outcomes were placental (histologic chorioamnionitis, vasculitis, funnisitis) and neonatal (intraventricular hemorrhage, ventriculomegaly, germinal matrix hemorrhage, periventricular leukomalacia). Odds ratios and 95% CI for the risk of histologic chorioamnionitis according to the respective latency intervals were 4.8 (1.0-22.9), 7.0 (1.1-43.1), 7.4 (2.1-42.3) in patients with pPROM. The risks of intracranial ultrasonic abnormalities, however, did not increased with prolonged latency. In the patients with preterm labor and intact membranes, the both risks did not increased with increasing latency. Therefore, this study was suggested that the risk of histologic chorioamnionitis increased with increasing latency, but there was no relationship between neonatal brain damage and latency interval after pPROM.

Rapid Prenatal Diagnosis of Down Syndrome Using Quantitative Fluorescent PCR in Uncultured Amniocytes

Rapid prenatal diagnosis of common chromosome aneuploidies have been successful through quantitative fluoresent PCR (QF-PCR) assays and small tandem repeat (STR) markers. The purpose of our study was to investigate the clinical feasibility for rapid prenatal detection of Down syndrome using the quantitative fluorescent PCR in uncultured amniocytes. DNA was extracted from uncultured amniotic fluid of normal karyotype (n=200) and of Down syndrome (n=21). It was amplified using QF-PCR with four STR markers located on chromosome 21. Among normal samples, the ranges of diallelic peaks for at least one STR marker were 1.0-1.3 for D21S11, 1.0-1.4 for D21S1411 and 1.0-1.5 for D21S1270. Down syndrome samples showed trisomic triallelic patterns or trisomic diallelic patterns. The sensitivity, specificity, and efficiency of the assay for detecting Down syndrome were 95.4%, 100%, and 99.5%, respectively. Rapid prenatal diagnosis of Down syndrome using QF-PCR is a reliable technique that aids clinical management of pregnancy.