Calciprotein particles as potential etiologic agents of idiopathic preterm birth

Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality and is often preceded by preterm premature rupture of the membranes (PPROM) without an identifiable cause. Pathological calcification, the deposition of hydroxyapatite (HA) in nonskeletal tissues, has been implicated in degenerative diseases including atherosclerosis and aneurism rupture. Among pathogenic mechanisms, the aberrant aggregation of HA into calciprotein particles (CPPs) and the HA-induced differentiation of mesenchymal cells into osteoblasts (ectopic osteogenesis) have been implicated. We explored the hypothesis that CPPs form in human amniotic fluid (AF), deposit in fetal membranes, and are linked mechanistically to pathogenic pathways favoring PTB. We demonstrated that fetal membranes from women with idiopathic PPROM frequently show evidence of ectopic calcification and expression of osteoblastic differentiation markers. Concentrations of fetuin-A, an endogenous inhibitor of ectopic calcification, were decreased in AF of idiopathic PPROM cases, which reflected their reduced functional capacity to inhibit calcification. Using long-term cultures of sterile AF, we demonstrated coaggregation of HA with endogenous proteins, including fetuin-A. The fetuin-HA aggregates exhibited progressive growth in vitro in a pattern similar to CPPs. When applied to amniochorion explants, AF-derived CPPs induced structural and functional pathological effects recapitulating those noted for PPROM. Our results demonstrate that disruption of protein-mineral homeostasis in AF stimulates the formation and deposition of CPPs, which may represent etiologic agents of idiopathic PPROM. Therapeutic or dietary interventions aimed at maintaining the balance between endogenous HA formation and fetuin reserve in pregnant women may therefore have a role in preventing PTB.

Limiting the Exposure of Select Fetuses to Intrauterine Infection/Inflammation Improves Short-Term Neonatal Outcomes in Preterm Premature Rupture of Membranes

BACKGROUND

To improve neonatal outcomes in pregnancies at heightened risk for early-onset neonatal sepsis (EONS), there is a need to identify fetuses that benefit from expectant management as opposed to early delivery. Detectable haptoglobin and haptoglobin-related protein (Hp&HpRP switch-on status) in cord blood has been proposed as a biomarker of antenatal exposure to intra-amniotic infection and/or inflammation (IAI), an important determinant of EONS.

SUBJECTS AND METHODS

We analyzed 185 singleton newborns delivered secondary to preterm premature rupture of membranes (PPROM). In 123 cases, amniocentesis was performed to exclude amniotic fluid (AF) infection. Delivery was indicated for 61 cases with confirmed infection. Women without AF infection (n = 62) and those without amniocentesis (n = 62) were managed expectantly. Interleukin 6 and Hp&HpRP switch-on status were evaluated by ELISA and Western blot. Newborns were followed prospectively for short-term outcomes until hospital discharge or death.

RESULTS

Newborns exposed antenatally to IAI had an increased risk of adverse neonatal outcome [OR: 3.0 (95% CI: 1.15-7.59)]. Increasing gestational age [OR: 0.61 (95% CI: 0.52-0.70)] and management with amniocentesis [OR: 0.37 (95% CI: 0.14-0.95)] lowered the newborn's risk of developing adverse outcomes.

DISCUSSION

In the setting of PPROM and IAI, early delivery benefits a select subgroup of fetuses that have not yet progressed to Hp&HpRP switch-on status.

Amniotic Fluid Soluble Myeloid Differentiation-2 (sMD-2) as Regulator of Intra-amniotic Inflammation in Infection-induced Preterm Birth

PROBLEM

TLR4 mediates host responses to pathogens through a mechanism that involves protein myeloid differentiation-2 (MD-2) and its soluble form sMD-2. The role of sMD2 in intra-amniotic inflammation-induced preterm birth has not been previously explored.

METHOD OF STUDY

Human amniotic fluid (AF) sMD-2 was studied by Western blotting in 152 AF samples of patients who had an amniocentesis to rule-out infection (yes infection, n = 50; no infection, n = 50) or women with normal pregnancy outcome (second trimester genetic karyotyping, n = 26; third trimester lung maturity testing, n = 26). Histological localization and mRNA expression of MD2 in fetal membranes were studied by immunohistochemistry and RT-PCR. The ability of fetal membrane to release sMD-2 and inflammatory cytokines was studied in vitro.

RESULTS

Human AF contains three sMD-2 proteoforms whose levels of expression were lower at term. Intra-amniotic infection upregulated sMD-2. MD-2 mRNA and immunohistochemistry findings concurred. In vitro, LPS and monensin increased, while cycloheximide decreased sMD-2 production. Recombinant sMD-2 modulated TNF-α and IL-6 levels in a dose- and time-dependent fashion.

CONCLUSION

sMD2 proteoforms are constitutively present in human AF. The intensity of the intra-amniotic inflammatory response to bacteria or perhaps to other TLR4 ligands may be facilitated through synthesis and release of sMD2 by the amniochorion.

Clitoral epidermoid cyst presenting as pseudoclitoromegaly of pregnancy

Objective Acquired clitoromegaly is rare and may result from hormonal and nonhormonal causes, and evaluation of the pregnant patient with clitoromegaly invokes a specific set of differential diagnoses. Methods Case report. Results We describe the case of a young woman with pregnancy-associated clitoral enlargement whose hormonal evaluation proved negative. Further investigation concluded that an epidermoid cyst was the culprit of her pseudoclitoromegaly. The patient underwent successful surgical resection and has had no recurrence at her subsequent pregnancy. Conclusion We review the differential diagnosis of clitoromegaly, including hormonal and nonhormonal causes, with focus on the evaluation of pregnancy-associated clitoromegaly.

Advances in medical diagnosis of intra-amniotic infection

INTRODUCTION

Intrauterine infection is a global problem and a significant contributor to morbidity and perinatal death. The host response to infection causes an inflammatory state that acts synergistically with microbial insult to induce preterm birth and fetal damage. Prompt and accurate diagnosis of intra-amniotic infection in the asymptomatic stage of the disease is critical for improved maternal and neonatal outcomes.

AREAS COVERED

This article provides an overview of the most recent progress, challenges, and opportunities for discovery and clinical implementation of various maternal serum, cervicovaginal, and amniotic fluid biomarkers in pregnancies complicated by intra-amniotic infection.

EXPERT OPINION

Clinically relevant biomarkers are critical to the accurate diagnostic of intrauterine infection. Front-end implementation of such biomarkers will also translate in lower incidence of early-onset neonatal sepsis (EONS) which is an important determinant of neonatal morbidity and mortality associated with prematurity. However, of the hundreds of differentially expressed proteins, only few may have clinical utility and thus function as biomarkers. The small number of validation studies along with barriers to implementation of technological innovations in the clinical setting are current limitations.

Heparin elevates circulating soluble fms-like tyrosine kinase-1 immunoreactivity in pregnant women receiving anticoagulation therapy

BACKGROUND

Alterations in circulating levels of pro- and antiangiogenic factors have been associated with adverse pregnancy outcomes. Heparin is routinely administered to pregnant women, but without clear knowledge of its impact on these factors.

METHODS AND RESULTS

We conducted a longitudinal study of 42 pregnant women. Twenty-one women received prophylactic heparin anticoagulation, and 21 healthy pregnant women served as controls. Compared with gestational age-matched controls, heparin treatment was associated with increased circulating levels of soluble fms-like tyrosine kinase-1 (sFlt-1) in the third trimester (P<0.05), in the absence of preeclampsia, placental abruption, or fetal growth restriction. Heparin had no effect on circulating levels of vascular endothelial growth factor, placenta growth factor, or soluble endoglin as assessed by ELISA. In vitro, low-molecular weight and unfractionated heparins stimulated sFlt-1 release from placental villous explants, in a dose- and time-dependent manner. This effect was not due to placental apoptosis, necrosis, alteration in protein secretion, or increased transcription. Western blot analysis demonstrated that heparin induced shedding of the N-terminus of Flt-1 both in vivo and in vitro as indicated by a predominant band of 100-112 kDa. By using an in vitro angiogenesis assay, we demonstrated that serum of heparin-treated cases inhibited both basal and vascular endothelial growth factor-induced capillary-like tube formation.

CONCLUSIONS

Heparin likely increases the maternal sFlt-1 through shedding of the extracellular domain of Flt-1 receptor. Our results imply that upregulation of circulating sFlt-1 immunoreactivity in pregnancy is not always associated with adverse outcomes, and that heparin's protective effects, if any, cannot be explained by promotion of angiogenesis.

Modulation of amniotic fluid activin-a and inhibin-a in women with preterm premature rupture of the membranes and infection-induced preterm birth

PROBLEM

Activins and inhibins are important modulators of inflammatory processes. We explored activation of amniotic fluid (AF) activin-A and inhibin-A system in women with intra-amniotic infection and preterm premature rupture of the membranes (PPROM).

METHOD OF STUDY

We analyzed 78 AF samples: '2nd trimester-control' (n=12), '3rd trimester-control' (n=14), preterm labor with intact membranes [positive-AF-cultures (n=13), negative-AF-cultures (n=13)], and PPROM [positive-AF-cultures (n=13), negative-AF-cultures (n=13)]. Activin-A levels were evaluated ex-vivo following incubation of amniochorion and placental villous explants with Gram-negative lipopolysaccharide (LPS) or Gram-positive (Pam3Cys) bacterial mimics. Ability of recombinant activin-A and inhibin-A to modulate inflammatory reactions in fetal membranes was explored through explants' IL-8 release.

RESULTS

Activin-A and inhibin-A were present in human AF and were gestational age-regulated. Activin-A was significantly upregulated by infection. Lower inhibin-A levels were seen in PPROM. LPS elicited release of activin-A from amniochorion, but not from villous explants. Recombinant activin-A stimulated IL-8 release from amniochorion, an effect that was not reversed by inhibin-A.

CONCLUSION

Human AF activin-A and inhibin-A are involved in biological processes linked to intra-amniotic infection/inflammation-induced preterm birth.

Proteomics mapping of cord blood identifies haptoglobin "switch-on" pattern as biomarker of early-onset neonatal sepsis in preterm newborns

Background

Intra-amniotic infection and/or inflammation (IAI) are important causes of preterm birth and early-onset neonatal sepsis (EONS). A prompt and accurate diagnosis of EONS is critical for improved neonatal outcomes. We sought to explore the cord blood proteome and identify biomarkers and functional protein networks characterizing EONS in preterm newborns.

Methodology/Principal Findings

We studied a prospective cohort of 180 premature newborns delivered May 2004-September 2009. A proteomics discovery phase employing two-dimensional differential gel electrophoresis (2D-DIGE) and mass spectrometry identified 19 differentially-expressed proteins in cord blood of newborns with culture-confirmed EONS (n = 3) versus GA-matched controls (n = 3). Ontological classifications of the proteins included transfer/carrier, immunity/defense, protease/extracellular matrix. The 1^st-level external validation conducted in the remaining 174 samples confirmed elevated haptoglobin and haptoglobin-related protein immunoreactivity (Hp&HpRP) in newborns with EONS (presumed and culture-confirmed) independent of GA at birth and birthweight (P<0.001). Western blot concurred in determining that EONS babies had conspicuous Hp&HpRP bands in cord blood (“switch-on pattern”) as opposed to non-EONS newborns who had near-absent “switch-off pattern” (P<0.001). Fetal Hp phenotype independently impacted Hp&HpRP. A Bayesian latent-class analysis (LCA) was further used for unbiased classification of all 180 cases based on probability of “antenatal IAI exposure” as latent variable. This was then subjected to 2^nd-level validation against indicators of adverse short-term neonatal outcome. The optimal LCA algorithm combined Hp&HpRP switch pattern (most input), interleukin-6 and neonatal hematological indices yielding two non-overlapping newborn clusters with low (≤20%) versus high (≥70%) probability of IAI exposure. This approach reclassified ∼30% of clinical EONS diagnoses lowering the number needed to harm and increasing the odds ratios for several adverse outcomes including intra-ventricular hemorrhage.

Conclusions/Significance

Antenatal exposure to IAI results in precocious switch-on of Hp&HpRP expression. As EONS biomarker, cord blood Hp&HpRP has potential to improve the selection of newborns for prompt and targeted treatment at birth.

Activation of the receptor for advanced glycation end products system in women with severe preeclampsia

CONTEXT

Activation of the receptor for advanced glycation end products (RAGE) mediates cellular injury. Soluble forms of RAGE [soluble RAGE (sRAGE), endogenous secretory (esRAGE)] bind RAGE ligands, thereby preventing downstream signaling and damage.

OBJECTIVES

The objective of the study was to characterize the changes in maternal serum, amniotic fluid, and cord blood soluble receptor for advanced glycation end products (sRAGE) during physiological gestation and to provide insight into mechanisms responsible for RAGE activation in preeclampsia.

DESIGN AND SETTINGS

This was a cross-sectional study at a tertiary university hospital.

PATIENTS

We studied 135 women in the following groups: nonpregnant controls (n = 16), healthy pregnant controls (n = 68), pregnant women with chronic hypertension (n = 13), or pregnant women with severe preeclampsia (sPE; n = 38).

INTERVENTIONS AND MAIN OUTCOME MEASURES

sRAGE and esRAGE levels were evaluated in vivo by ELISA in maternal serum, amniotic fluid, and cord blood and in vitro after stimulation of the amniochorion and placental explants with lipopolysaccharide or xanthine/xanthine oxidase. Placenta and amniochorion were immunostained for RAGE. Real-time quantitative PCR measured RAGE mRNA.

RESULTS

Pregnant women had significantly decreased serum sRAGE compared with nonpregnant subjects (P < 0.001). sPE women had higher serum and amniotic fluid sRAGE and esRAGE relative to those expected for gestational age (P < 0.001). Cord blood sRAGE remained unaffected by sPE. RAGE immunoreactivity and mRNA expression appeared elevated in the amniochorion of sPE women. Xanthine/xanthine oxidase (but not lipopolysaccharide) significantly up-regulated the release of sRAGE (P < 0.001) in the amniochorion explant system.

CONCLUSIONS

Fetal membranes are a rich source of sRAGE. Elevated maternal serum and amniotic fluid sRAGE and esRAGE, paralleled by increased RAGE expression in the amniochorion, suggest activation of this system in sPE.

IL-6 trans-signaling system in intra-amniotic inflammation, preterm birth, and preterm premature rupture of the membranes

Classic IL-6 signaling is conditioned by the transmembrane receptor (IL-6R) and homodimerization of gp130. During trans-signaling, IL-6 binds to soluble IL-6R (sIL-6R), enabling activation of cells expressing solely gp130. Soluble gp130 (sgp130) selectively inhibits IL-6 trans-signaling. To characterize amniotic fluid (AF) IL-6 trans-signaling molecules (IL-6, sIL-6R, sgp130) in normal gestations and pregnancies complicated by intra-amniotic inflammation (IAI), we studied 301 women during second trimester (n = 39), third trimester (n = 40), and preterm labor with intact (n = 131, 85 negative IAI and 46 positive IAI) or preterm premature rupture of membranes (PPROM; n = 91, 61 negative IAI and 30 positive IAI). ELISA, Western blotting, and real-time RT-PCR were used to investigate AF, placenta, and amniochorion for protein and mRNA expression of sIL-6R, sgp130, IL-6R, and gp130. Tissues were immunostained for IL-6R, gp130, CD15(+) (polymorphonuclear), and CD3(+) (T cell) inflammatory cells. The ability of sIL-6R and sgp130 to modulate basal and LPS-stimulated release of amniochorion matrix metalloprotease-9 was tested ex vivo. We showed that in physiologic gestations, AF sgp130 decreases toward term. AF IL-6 and sIL-6R were increased in IAI, whereas sgp130 was decreased in PPROM. Our results suggested that fetal membranes are the probable source of AF sIL-6R and sgp130. Immunohistochemistry and RT-PCR revealed increased IL-6R and decreased gp130 expression in amniochorion of women with IAI. Ex vivo, sIL-6R and LPS augmented amniochorion matrix metalloprotease-9 release, whereas sgp130 opposed this effect. We conclude that IL-6 trans-signaling molecules are physiologic constituents of the AF regulated by gestational age and inflammation. PPROM likely involves functional loss of sgp130.

Cord blood erythropoietin and interleukin-6 for prediction of intraventricular hemorrhage in the preterm neonate

OBJECTIVE

To evaluate cord blood erythropoietin (EPO) and interleukin-6 (IL-6) levels to predict preterm infants at risk of developing intraventricular hemorrhage (IVH).

METHODS

Levels of umbilical cord EPO, acid-base status and IL-6 were analyzed in 116 consecutive, preterm newborns (GA at delivery: 29 [23-34 ] weeks) born to mothers who had a clinically indicated amniocentesis to rule out infection. Early-onset neonatal sepsis (EONS) was diagnosed using symptoms, hematological criteria and blood cultures.

RESULTS

IVH was diagnosed by cranial ultrasounds. The prevalence of IVH in our population was 25% (29/116). There was a direct relationship between cord blood EPO and cord blood IL-6 concentration (r = 0.225, p = 0.014), independent of GA at birth. Elevated cord blood EPO levels (r = 0.182, p = 0.016) and GA at birth (r =  -0.236, p = 0.004) remained significant independent factors associated with the risk of IVH, when evaluated with stepwise logistic regression analyses. Cord blood IL-6, pH, and EONS were not associated with IVH. These relationships remained following correction for GA at birth (p = 0.027).

CONCLUSIONS

Our results suggest that elevation in cord blood EPO may predict newborns at risk for IVH, independent of fetal inflammatory status. Further studies are warranted to confirm this association.

Amniotic fluid angiopoietin-1, angiopoietin-2, and soluble receptor tunica interna endothelial cell kinase-2 levels and regulation in normal pregnancy and intraamniotic inflammation-induced preterm birth

BACKGROUND

Angiopoietin-1 (Ang-1) and Ang-2 act selectively on endothelial cells by engaging the Tunica interna endothelial cell kinase-2 (Tie2) receptor. A soluble form of Tie2 (sTie2) blocks angiopoietin bioactivity.

OBJECTIVE

The aim of the study was to characterize changes and expression patterns of Ang-1, Ang-2, and sTie2 in amniotic fluid (AF) and placenta during human pregnancy and intraamniotic inflammation (IAI)-induced preterm birth.

DESIGN AND SETTING

We conducted a cross-sectional study at a tertiary university hospital.

PATIENTS

AF levels of Ang-1, Ang-2, and sTie2 were evaluated in 176 women during second trimester (n = 40), third trimester (n = 37), and preterm labor (positive IAI, n = 50; negative IAI, n = 49). Placenta and cord blood of select women were analyzed.

MAIN OUTCOME MEASURES

Ang-1, Ang-2, sTie2, and IL-6 were evaluated by ELISA. Real-time PCR measured Ang-1, Ang-2, and Tie2 placental mRNA levels. Placenta was immunostained for Ang-1 and Ang-2. Placental explant cultures were stimulated with lipopolysaccharide, Pam3Cys, and modulators of protein synthesis/secretion (cycloheximide, monensin, and brefeldin A).

RESULTS

In normal pregnancy, the levels and ratios of AF Ang-1, Ang-2, and sTie2 varied with gestational age (GA) (P < 0.001). PCR revealed corresponding changes in placental Ang-1 and Ang-2, but not Tie2, mRNA. IAI raised AF Ang-1, Ang-2, and sTie2 above the expected level for GA without affecting their placental mRNA. Ang-2 immunoreactivity appeared enhanced in areas of villous edema. AF Ang-2/Ang-1 ratio was an important determinant of cord blood IL-6 (P < 0.001). Ex-vivo, sTie2 release was increased by Golgi disrupting but not bacterial mimic agents.

CONCLUSIONS

Ang-1, Ang-2, and sTie2 are physiological constituents of AF that are GA and IAI regulated. Ang-2/Ang-1 ratio may play a role in modulating the fetal inflammatory response to IAI. Placental sTie2 shedding likely involves a Golgi-mediated mechanism.

Is the rate of congenital heart defects detected by fetal echocardiography among pregnancies conceived by in vitro fertilization really increased?: a case-historical control study

OBJECTIVE

We investigated the prenatal prevalence of congenital heart defects (CHDs) among in vitro fertilization (IVF) pregnancies at a referral program in the United States.

METHODS

Study patients were referred for fetal echocardiography between April 1, 2006, and May 1, 2009, due to IVF. An IVF pregnancy was defined as a patient who conceived with IVF with or without intracytoplasmic sperm injection. Congenital heart defect odds relative to historical data were calculated by standard methods. P < .05 was considered statistically significant.

RESULTS

During the study period, we performed fetal echocardiography on 749 consecutive IVF pregnancies. Overall, the frequency of CHDs was 1.1% (95% confidence interval, 0.3%-1.8%) per pregnancy. Compared to earlier historical population data, IVF pregnancies had a significantly higher risk of CHDs (odds ratios, 7.3 [3.6-14.7] and 2.9 [1.4-5.9], respectively). However, compared to more contemporary population data, there was no difference in the CHD risk between IVF gestations and naturally conceived pregnancies. Further analysis indicated that IVF twin pregnancies were as much as 12.5 (4.6-33.5) times as likely to have CHDs compared to a general population.

CONCLUSIONS

In this study population, the frequency of CHDs in IVF pregnancies was higher than early historical population data; however, it was similar to that of a more contemporary general population. Further analysis showed that this increase was mainly driven by IVF twin gestations. Previous reports of increased CHD risk in pregnancies conceived via IVF may have been due, in part, to an increased frequency of higher-order pregnancies seen among these patients.

The role of urinary soluble endoglin in the diagnosis of pre-eclampsia: comparison with soluble fms-like tyrosine kinase 1 to placental growth factor ratio

OBJECTIVE

Endoglin, an anti-angiogenic glycoprotein expressed on endothelial cells, has been proposed recently as a biomarker of pre-eclampsia (PE). Given that PE is characterised by an imbalance of angiogenic factors, we sought to determine the clinical utility of urinary soluble endoglin, relative to the soluble fms-like tyrosine kinase 1 to placental growth factor (PlGF) ratio, in the diagnosis of PE during gestation.

DESIGN

Prospective observational cohort.

SETTING

Tertiary referral university hospital.

POPULATION

Two hundred and thirty-four pregnant women were enrolled prospectively in the following groups: healthy controls, n = 63; gestational age (GA), median (interquartile range), 33 weeks (27-39 weeks); chronic hypertension, n = 27; GA, 33 weeks (30-36 weeks); mild PE, n = 38; GA, 37 weeks (34-40 weeks); severe PE, n = 106; GA, 32 weeks (29-37 weeks).

METHODS

Free urinary levels of soluble endoglin, soluble fms-like tyrosine kinase 1 and PlGF were measured by sensitive and specific immunoassay. Levels for all urinary analytes were normalised to creatinine.

MAIN OUTCOME MEASURES

Urinary soluble endoglin, and the soluble fms-like tyrosine kinase 1 to PlGF ratio.

RESULTS

In healthy controls, urinary soluble endoglin levels were increased significantly at term relative to those earlier in gestation. Severe PE was characterised by an increased urinary level of soluble endoglin, soluble fms-like tyrosine kinase 1, protein to creatinine ratio and soluble fms-like tyrosine kinase 1 to PlGF ratio compared with all other groups. There was a direct correlation between urinary soluble endoglin and proteinuria that remained after GA correction (R = 0.382, P < 0.001). Urinary soluble endoglin could not differentiate mild PE from severe preterm PE. Overall, soluble endoglin had the ability to discriminate PE from chronic hypertension and healthy controls only in women who were evaluated at <37 weeks of GA. The sensitivity, specificity and accuracy of urinary soluble endoglin alone in the diagnosis of PE or in the identification of women with PE requiring a mandated delivery before 37 weeks of gestation were 70%, 86% and 76%, respectively. These values were inferior to those of the soluble fms-like tyrosine kinase 1 to PlGF ratio (P < 0.001). The addition of urinary soluble endoglin did not improve the diagnostic accuracy of the soluble fms-like tyrosine kinase 1 to PlGF ratio alone.

CONCLUSIONS

We have provided evidence that soluble endoglin is present and elevated in the urine of women who develop preterm PE. Urinary soluble endoglin has only limited ability to determine the severity of PE and to distinguish between PE and chronic hypertension both preterm and at term. Compared with urinary soluble endoglin, the soluble fms-like tyrosine kinase 1 to PlGF ratio remains a better marker of disease presence, severity and outcome.

Characterization of RAGE, HMGB1, and S100beta in inflammation-induced preterm birth and fetal tissue injury

Immune activation represents an adaptive reaction triggered by both noxious exogenous (microbes) and endogenous [high mobility group box-1 protein (HMGB1), S100 calcium binding proteins] inducers of inflammation. Cell stress or necrosis lead the release of HMGB1 and S100 proteins in the extracellular compartment where they act as damage-associated molecular pattern molecules (or alarmins) by engaging the receptor for advanced glycation end-products (RAGE). Although the biology of RAGE is dictated by the accumulation of damage-associated molecular pattern molecules at sites of tissue injury, the role of RAGE in mediating antenatal fetal injury remains unknown. First, we studied the relationships at birth between the intensity of human fetal inflammation and sRAGE (an endogenous RAGE antagonist), HMGB1, and S100beta protein. We found significantly lower sRAGE in human fetuses that mounted robust inflammatory responses. HMGB1 levels correlated significantly with levels of interleukin-6 and S100beta in fetal circulation. We then evaluated the levels and areas of tissue expression of RAGE, HMGB1, and S100beta in specific organs of mouse fetuses on E16. Using an animal model of endotoxin-induced fetal damage and preterm birth, we determined that inflammation induces a significant change in expression of RAGE and HMGB1, but not S100beta, at sites of tissue damage. Our findings indicate that RAGE and HMGB1 may be important mediators of cellular injury in fetuses delivered in the setting of inflammation-induced preterm birth.

Fetal renal artery impedance as assessed by Doppler ultrasound in pregnancies complicated by intraamniotic inflammation and preterm birth

OBJECTIVE

The objective of the study was to evaluate the fetal renal artery impedance in the context of inflammation-associated preterm birth.

STUDY DESIGN

We conducted a prospective Doppler assessment of the fetal renal artery impedance in 70 singleton fetuses. The study group consisted of 56 premature fetuses (median, 28.1 [interquartile range, 25.3-30.6] weeks at enrollment). Gestational age (GA) reference ranges were generated based on fetuses with uncomplicated pregnancies (n = 14). Doppler studies included renal artery pulsatility index (PI), resistance index (RI), systolic/diastolic (S/D) ratio, and presence or absence of end-diastolic blood flow. Proteomic profiling (surface-enhanced laser desorption ionization time-of-flight) was used for assessment of intraamniotic inflammation and biomarker peak corresponding to beta2-microglubin. Data were interpreted in relationship to amniotic fluid index (AFI), cord blood interleukin (IL)-6 and erythropoietin (EPO) levels. The cardiovascular and metabolic profiles of the neonates were investigated in the first 24 hours of life.

RESULTS

Fetuses delivered by mothers with intraamniotic inflammation had higher cord blood IL-6 but not EPO levels. Fetal inflammation did not affect either renal artery PI, RI, S/D ratio, or end-diastolic blood flow. Neonates delivered in the context of intraamniotic inflammation had higher serum blood urea nitrogen levels, which correlated significantly with AF IL-6 levels. The renal artery RI and SD ratio were inversely correlated with the AFI independent of GA, cord blood IL-6, and status of the membranes.

CONCLUSION

The fetus is capable of sustaining normal renal artery impedance despite inflammation. Resistance in the renal vascular bed affects urine output independent of inflammation.

Fetal inflammatory response in women with proteomic biomarkers characteristic of intra-amniotic inflammation and preterm birth

OBJECTIVE

To determine the relationship between presence of amniotic fluid (AF) biomarkers characteristic of inflammation (defensins 2 and 1 and calgranulins C and A) and fetal inflammatory status at birth.

DESIGN

Prospective observational cohort.

SETTING

Tertiary referral University hospital.

POPULATION

One hundred and thirty-two consecutive mothers (gestational age, median [interquartile range]: 29.6 [24.1-33.1] weeks) who had a clinically indicated amniocentesis to rule out infection and their newborns.

METHODS

Intra-amniotic inflammation was diagnosed by mass spectrometry surface-enhanced-laser-desorption-ionization time of flight (SELDI-TOF). The AF proteomic fingerprint (mass-restricted [MR] score) ranges from 0-4 (none to all biomarkers present). The intensity of intra-amniotic inflammation was graded based on the number of proteomic biomarkers: MR score 0: 'no' inflammation, MR score 1-2: 'minimal' inflammation and MR score 3-4: 'severe' inflammation. At birth, cord blood was obtained for all women. Severity of histological chorioamnionitis and early-onset neonatal sepsis (EONS) was based on established histological and haematological criteria. Interleukin-6 (IL-6) levels were measured by sensitive immunoassays. The cord blood-to-AF IL-6 ratio was used as an indicator of the differential inflammatory response in the fetal versus the AF compartment.

MAIN OUTCOME MEASURES

To relate proteomic biomarkers of intra-amniotic infection to cord blood IL-6 and to use the latter as the primary marker of fetal inflammatory response.

RESULTS

Women with intra-amniotic inflammation delivered at an earlier gestational age (analysis of variance, P<0.001) and had higher AF IL-6 levels (P<0.001). At birth, neonates of women with severe intra-amniotic inflammation had higher cord blood IL-6 levels (P=0.002) and a higher frequency of EONS (P=0.002). EONS was characterised by significantly elevated cord blood IL-6 levels (P<0.001). Of the 39 neonates delivered by mothers with minimal intra-amniotic inflammation, 15 (39%) neonates had umbilical cord blood IL-6 levels above the mean for the group and 2 neonates had confirmed sepsis. The severity of the neutrophilic infiltrate in the chorionic plate (P<0.001), choriodecidua (P=0.002), umbilical cord (P<0.001) but not in the amnion (P>0.05) was an independent predictor of the cord blood-to-AF IL-6 ratio. Relationships were maintained following correction for gestational age, birthweight, amniocentesis-to-delivery interval, caesarean delivery, status of the membranes, race, MR score and antibiotics and steroid exposure.

CONCLUSIONS

We provide evidence that presence of proteomic biomarkers characteristic of inflammation in the AF is associated with an increased inflammatory status of the fetus at birth. Neonates mount an increased inflammatory status and have positive blood cultures even in the context of minimal intra-amniotic inflammation.

Fetal heart rate monitoring patterns in women with amniotic fluid proteomic profiles indicative of inflammation

We hypothesized that abnormal fetal heart rate monitoring patterns (FHR-MPs) occur more often in pregnancies complicated by intra-amniotic inflammation. Therefore, our objective was to examine the relationships among FHR-MP abnormalities, intra-amniotic inflammation and/or infection, acute histological chorioamnionitis, and early-onset neonatal sepsis (EONS) in pregnancies complicated by preterm birth. Additionally, the ability of various FHR-MPs to predict EONS was investigated. FHR-MPs from 87 singleton premature neonates delivered within 48 hours from amniocentesis (gestational age, mean +/- SD: 28.9 +/- 3.3 weeks) were analyzed blindly using strict National Institute of Child Health and Human Development criteria. Strips were evaluated at three time points: at admission, at amniocentesis, and prior to delivery. Intra-amniotic inflammation was established based on a previously validated proteomic fingerprint (mass-restricted score). Diagnoses of histological chorioamnionitis and EONS were based on well-recognized pathological, clinical, and laboratory criteria. We determined that fetuses of women with severe intra-amniotic inflammation had a higher FHR baseline throughout the entire monitoring period and an increased frequency of a nonreactive FHR-MP at admission. Of all FHR-MPs, a nonreassuring test at admission had 32% sensitivity, 95% specificity, 73% positive predictive value, 77% negative predictive value, and 76% accuracy in predicting EONS. Although a nonreassuring FHR-MP at admission was significantly associated with EONS after correcting for gestational age (odds ratio, 5.6; 95% confidence interval, 1.2 to 26.2; P = 0.030), the majority of the neonates that developed EONS had an overall reassuring FHR-MP. Nonreassuring FHR-MPs at either amniocentesis or delivery had no association with EONS. We conclude that in cases complicated by preterm birth, a nonreassuring FHR-MP at the initial evaluation is a specific but not a sensitive predictor of EONS. An abnormal FHR-MP can thus raise the level of awareness that a fetus with EONS may be born, but it is not a useful clinical indicator of the need for antibiotic treatment of the neonate.

First-trimester ultrasound: current uses and applications

This article is aimed to aid the sonographer and medical care provider in better interpretation and clinical application of first-trimester ultrasound findings in early pregnancy. We review current uses, applications, and interpretations of first-trimester ultrasound. A discussion of basic embryology and normal as well as abnormal first-trimester sonographic findings are discussed. We also cover the utility of the first-trimester ultrasound in screening for fetal aneuploidy. Attention is also given to the role of the first-trimester ultrasound in the prediction of adverse perinatal and maternal outcomes.

Prenatal course of isolated muscular ventricular septal defects diagnosed only by color Doppler sonography: single-institution experience

OBJECTIVE

Counseling patients with an isolated ventricular septal defect (i-VSD) is clinically important because with high-resolution ultrasound equipment, more small muscular VSDs are now being diagnosed. The prevalence of these lesions is not yet completely described, and the frequency with which muscular VSDs resolve in utero has also not been extensively reported.

METHODS

We investigated the perinatal course of isolated muscular VSDs diagnosed only on color Doppler examinations and followed between January 1, 2005, and December 31, 2006. A complete evaluation of the fetal heart was performed by gray scale, spectral Doppler, and color Doppler examinations.

RESULTS

We performed a total of 2583 fetal echocardiographic examinations on 2410 fetuses during 2318 pregnancies. The study group included 78 twin gestations (3.4%) and 7 triplet gestations (0.3%). There were 16 fetuses with an i-VSD (6.6/1000 fetuses) within the study group. The mean gestational age +/- SD at diagnosis was 23.5 +/- 4.3 weeks. Two of the i-VSDs (12.5%) spontaneously resolved prenatally. One fetus with an i-VSD had trisomy 21 and also had increased nuchal translucency in the first trimester. One i-VSD was diagnosed among 22 fetuses with trisomy 21 examined during the study period.

CONCLUSIONS

An i-VSD is a common congenital heart defect. Prenatal resolution of i-VSDs is less frequent than reported in the literature. A larger cohort is needed to provide a better risk estimate for aneuploidy in the presence of an i-VSD.

Nucleated red blood cells are a direct response to mediators of inflammation in newborns with early-onset neonatal sepsis

OBJECTIVE

The objective of the study was to test the hypothesis that inflammation modulates fetal erythroblastosis and/or the release of nucleated red blood cells (NRBCs) independent of hypoxia or fetal stress. We sought to determine whether fetal inflammation is associated with an elevation in neonatal NRBC count in the setting of inflammation-associated preterm birth.

STUDY DESIGN

The relationships between peripheral NRBC count, histological chorioamnionitis, umbilical cord interleukin (IL)-6, erythropoietin (EPO), cortisol, and acid-base status were analyzed in 68 preterm singletons, born to mothers who had an amniocentesis to rule out infection. Proteomic profiling of amniotic fluid identified presence of intraamniotic inflammation according to established parameters. NRBC counts were assessed within 1 hour of birth. Early-onset neonatal sepsis (EONS) was established based on hematological and microbiological indices. IL-6, EPO, and cortisol levels were measured by immunoassays. Fetal acid-base status was determined within 10 minutes of delivery. Parametric or nonparametric statistics were used.

RESULTS

Fetuses with EONS (n = 19) were delivered at earlier gestational ages (mean +/- SD: 27.1 +/- 2.8 weeks, P = .001) and more often by mothers with intraamniotic inflammation (P = .022) and histological chorioamnionitis (P < .001). Neonates with EONS had higher absolute NRBC counts (P = .011). NRBC counts were directly correlated with cord blood IL-6 levels (P < .001) but not with EPO, cortisol or parameters of acid-base status levels regardless of EONS status. These relationships remained following correction for gestational age, diabetes, intrauterine growth restriction, and steroid exposure.

CONCLUSION

In the setting of inflammation-associated preterm birth and in the absence of hypoxia, elevations in NRBCs in the early neonatal period may be a direct response of exposure to inflammatory mediators in utero.

Multidimensional system biology: genetic markers and proteomic biomarkers of adverse pregnancy outcome in preterm birth

Premature birth before 37 weeks of gestation is a significant public health problem. Each year, 4.5 million premature infants are born worldwide. Despite extensive research and a variety of interventions, the rate of preterm birth has steadily increased over the past 20 years and reached a high of 12.8% in 2006. The etiology of most preterm births remains elusive and is likely multifactorial, with many pathophysiological pathways involved, such as excessive stretching, oxidative stress, decidual hemorrhage, and infection. Genomics and proteomics have emerged to provide a better comprehension of the pathophysiological conditions leading to preterm birth, thereby providing a perspective for improving neonatal outcome.

Relationships of maternal serum levels of vascular endothelial growth factor and tensile strength properties of the cervix in a rat model of chronic hypoxia

OBJECTIVE

It has been shown that hypoxia leads to alterations in maternal serum levels of vascular endothelial growth factor (VEGF). In this study, we sought to test the hypothesis that chronic hypoxia increases maternal serum levels of VEGF, which in turn cause measurable changes in the viscoelastic properties of the rat uterine cervix.

STUDY DESIGN

Timed-pregnant adult Sprague-Dawley rats were exposed to hypoxia beginning on day 17 of gestation (term = day 22). The following groups of animals were studied: (1) nonpregnant controls (NP, n = 6); (2) normoxia 21% fraction of inspired oxygen (FiO2) (NMX, n = 6); and (3) severe hypoxia 10% FiO2 (HPX; n = 5). A hypoxic chamber was used to assure consistent hypoxic environment. Animals were killed on day 21 of gestation (before labor). Maternal blood was collected immediately following anesthesia and prior to euthanasia. Free serum levels of VEGF were measured by highly specific immunoassays. Tensile strength properties of the cervix were assessed using a stretching regimen designed to mimic labor. Physical parameters measured were: indicators of viscoelasticity (slope; measure of stiffness), plasticity (yield point [YP]; moment the tissue changes its properties from elastic to plastic), strength (break point [BP]; moment of tissue disruption), and displacement at YP (marks the duration of the viscoelastic phase of the stretching) and BP (a measure of the strength of the material). Data were normalized to the dry weight of the cervix.

RESULTS

Hypoxia is associated with increased serum levels of VEGF compared to NP or NMX groups (P = .001). Cervical stiffness was lower in NMX, compared with NP animals (P = .004), and was not significantly influenced by hypoxia (P > .05). Overall there was a significant inverse correlation between slope and maternal serum levels of VEGF (r = -0.85, P < .001). The force required to reach YP was significantly higher for the NP, compared with NMX and HPX groups (P = .004). Hypoxia did not alter the force required to reach the YP (NMX vs HPX, P > .05). Conversely, hypoxia significantly decreased the displacement at YP, indicating a shortening of the elastic phase (NMX vs HPX, P = .021). There was a significant inverse correlation between maternal serum levels of VEGF and the displacement at YP (r = -0.68, P = .002). In vivo, hypoxia decreased the force required to reached the BP (NMX vs HPX, P = .025), but there was no correlation between the levels of maternal serum VEGF and this indicator (r = -0.35, P = .170).

CONCLUSION

Chronic hypoxia induces measurable changes in maternal serum levels of VEGF and tensile properties of the rat cervix, specifically a shortening of the elastic phase. Hypoxia decreases the cervical strength to stretch and predisposes to rupture, but this effect seems to be unrelated to maternal serum levels of VEGF.

Prevalence of congenital heart defects in monochorionic/diamniotic twin gestations: a systematic literature review

OBJECTIVE

Congenital heart defects (CHDs) affect approximately 0.5% of all neonates. Recent literature points to a possible increase in the CHD prevalence among monochorionic/diamniotic (MC/DA) twin gestations. We hypothesized that MC/DA twin pregnancy is a risk factor for CHD.

METHODS

A systematic review of all published English literature was conducted on MEDLINE (Ovid and PubMed) from January 2000 through April 2007 using the medical subject heading terms "congenital heart defect" and "monozygotic twins." Four observational studies were included in the final analysis. Published historical data were used for the population background risk of CHD. Relative risk (RR) estimates with 95% confidence intervals (CIs) were calculated by fixed and random effect models.

RESULTS

We included a total of 40 fetuses with CHDs among 830 fetuses from MC/DA twin gestations. Compared with the population, CHDs were significantly more prevalent in MC/DA twins regardless of the presence of twin-twin transfusion syndrome (TTTS) (RR, 9.18; 95% CI, 5.51-15.29; P < .001). Monochorionic/diamniotic twin gestations affected by TTTS were more likely to be complicated by CHDs than those that did not have TTTS (RR, 2.78; 95% CI, 1.03-7.52; P = .04). Ventricular septal defects were the most frequent heart defects. Pulmonary stenosis and atrial septal defects were significantly more prevalent in pregnancies complicated with TTTS.

CONCLUSIONS

Monochorionic/diamniotic twin gestation appears to be a risk factor for CHDs. Conditions that lead to abnormal placentation may also contribute to abnormal heart development, especially in MC/DA twin pregnancies complicated with TTTS. Fetal echocardiography may be considered for all MC/DA twin gestations because ventricular septal defects and pulmonary stenosis are the most common defects.