Proteomics/diagnosis of chorioamnionitis and of relationships with the fetal exposome

Prenatal exposure to environmental contaminants and cord serum metabolite profiles in future immune-mediated diseases

BACKGROUND

Prenatal exposure to environmental contaminants is a significant health concern because it has the potential to interfere with host metabolism, leading to adverse health effects in early childhood and later in life. Growing evidence suggests that genetic and environmental factors, as well as their interactions, play a significant role in the development of autoimmune diseases.

OBJECTIVE

In this study, we hypothesized that prenatal exposure to environmental contaminants impacts cord serum metabolome and contributes to the development of autoimmune diseases.

METHODS

We selected cord serum samples from All Babies in Southeast Sweden (ABIS) general population cohort, from infants who later developed one or more autoimmune-mediated and inflammatory diseases: celiac disease (CD), Crohn's disease (IBD), hypothyroidism (HT), juvenile idiopathic arthritis (JIA), and type 1 diabetes (T1D) (all cases, N = 62), along with matched controls (N = 268). Using integrated exposomics and metabolomics mass spectrometry (MS) based platforms, we determined the levels of environmental contaminants and metabolites.

RESULTS

Differences in exposure levels were found between the controls and those who later developed various diseases. High contaminant exposure levels were associated with changes in metabolome, including amino acids and free fatty acids. Specifically, we identified marked associations between metabolite profiles and exposure levels of deoxynivalenol (DON), bisphenol S (BPS), and specific per- and polyfluorinated substances (PFAS).

IMPACT STATEMENT

Abnormal metabolism is a common feature preceding several autoimmune and inflammatory diseases. However, few studies compared common and specific metabolic patterns preceding these diseases. Here we hypothesized that exposure to environmental contaminants impacts cord serum metabolome, which may contribute to the development of autoimmune diseases. We found differences in exposure levels between the controls and those who later developed various diseases, and importantly, on the metabolic changes associated with the exposures. High contaminant exposure levels were associated with specific changes in metabolome. Our study suggests that prenatal exposure to specific environmental contaminants alters the cord serum metabolomes, which, in turn, might increase the risk of various immune-mediated diseases.

The amniotic fluid proteome changes across gestation in humans and rhesus macaques

Amniotic fluid is a complex biological medium that offers protection to the fetus and plays a key role in normal fetal nutrition, organogenesis, and potentially fetal programming. Amniotic fluid is also critically involved in longitudinally shaping the in utero milieu during pregnancy. Yet, the molecular mechanism(s) of action by which amniotic fluid regulates fetal development is ill-defined partly due to an incomplete understanding of the evolving composition of the amniotic fluid proteome. Prior research consisting of cross-sectional studies suggests that the amniotic fluid proteome changes as pregnancy advances, yet longitudinal alterations have not been confirmed because repeated sampling is prohibitive in humans. We therefore performed serial amniocenteses at early, mid, and late gestational time-points within the same pregnancies in a rhesus macaque model. Longitudinally-collected rhesus amniotic fluid samples were paired with gestational-age matched cross-sectional human samples. Utilizing LC-MS/MS isobaric labeling quantitative proteomics, we demonstrate considerable cross-species similarity between the amniotic fluid proteomes and large scale gestational-age associated changes in protein content throughout pregnancy. This is the first study to compare human and rhesus amniotic fluid proteomic profiles across gestation and establishes a reference amniotic fluid proteome. The non-human primate model holds promise as a translational platform for amniotic fluid studies.

Utilizing Amniotic Fluid Metabolomics to Monitor Fetal Well-Being: A Narrative Review of the Literature

Fetal and perinatal periods are critical phases for long-term development. Early diagnosis of maternal complications is challenging due to the great complexity of these conditions. In recent years, amniotic fluid has risen in a prominent position in the latest efforts to describe and characterize prenatal development. Amniotic fluid may provide real-time information on fetal development and metabolism throughout pregnancy as substances from the placenta, fetal skin, lungs, gastric fluid, and urine are transferred between the mother and the fetus. Applying metabolomics to monitor fetal well-being, in such a context, could help in the understanding, diagnosis, and treatment of these conditions and is a promising area of research. This review shines a spotlight on recent amniotic fluid metabolomics studies and their methods as an interesting tool for the assessment of many conditions and the identification of biomarkers. Platforms in use, such as proton nuclear magnetic resonance (¹H NMR) and ultra-high-performance liquid chromatography (UHPLC), have different merits, and a combinatorial approach could be valuable. Metabolomics may also be used in the quest for habitual diet-induced metabolic signals in amniotic fluid. Finally, analysis of amniotic fluid can provide information on exposure to exogenous substances by detecting the exact levels of metabolites carried to the fetus and associated metabolic effects.

Fetal-fluid proteome analyses in late-term healthy pregnant mares and in mares with experimentally induced ascending placentitis

Characterisation of fetal fluids in healthy and disease states of pregnant mares can help to unravel the pathophysiology and to identify putative markers of disease. Thus, this study aimed to compare the protein composition of: (1) amniotic and allantoic fluids of healthy mares obtained immediately after euthanasia and (2) allantoic fluid harvested via centesis before and after experimental induction of placentitis via transcervical inoculation of Streptococcus equi ssp zooepidemicus in healthy mares. Fetal fluids were analysed with a high-throughput proteomic technique after in-gel digestion. Statistical comparisons were performed following normalisation of peptide spectral match. Global normalisation was performed to calculate relative expression. There were 112 unique proteins present in both allantoic and amniotic fluids. There were 13 and 29 proteins defined as amniotic- or allantoic-specific respectively that were present in at least two fluid samples. Another 26 proteins were present in both amniotic and allantoic fluids. Panther DB functional classification grouped fetal-fluid proteins as transfer carriers, signalling molecules, receptors, immunity, hydrolase, enzymes, membrane traffic, cytoskeleton, cell adhesion, calcium binding and extracellular matrix. Experimentally induced placentitis resulted in 10 proteins being upregulated and 10 downregulated in allantoic fluid. Newly identified proteins and changes in the fetal-fluid proteome provide clues about the physiology of pregnancy and pathogenesis of placentitis.

Association of histological and clinical chorioamnionitis with perinatal and neonatal outcome

Objectives: We investigated the incidence and outcome of clinical and histological chorioamnionitis (CA) and the associated risk factors in an emerging provincial perinatal center in 2014-2015.Study design: Based on the suspected and proven clinical infection in the third trimester of pregnancy, placenta and accessories from singleton deliveries were routinely examined histologically. The incidence of CA and associated fetal and neonatal outcome were compared by the total deliveries.Results: Of the 14,166 deliveries in 12 months, infection and inflammation were found in 373 out of 2372 (15.7%) placentas subjected to histological examination and diagnosed as CA (2.6%). These cases were divided into four groups as histological CA only (HCA, n = 335), clinical and histological CA (HCC, n = 20), clinical CA only (CCA, n = 18) and non-CA control (CON, n = 1999). Thus, an incidence of histological CA was 2.5% (355/14 166) in this birth population. Compared to CON, HCA group was more likely to have premature rupture of membrane, antenatal antibiotic use, gestational age <34 weeks, fetal distress, positive bacterial culture from vaginal secretions, and early-onset sepsis in newborns (all p ≤ .01), which were associated with perinatal risk factors of CA. In the very preterm subgroups, more stillbirths and death at delivery and neonatal intensive care unit admissions (p < .001) were found in the CA group.Conclusions: The results suggested that histological CA was associated with early-onset sepsis and combined perinatal comorbidities which are of more diagnostic importance than clinical only CA. The placental histological examination should be routinely performed in very preterm births to better assess perinatal and neonatal outcome.

Components of the antepartum, intrapartum, and postpartum exposome impact on distinct short-term adverse neonatal outcomes of premature infants: A prospective cohort study

We aimed to test the hypothesis that determinants of the perinatal clinical exposome related to the underlying etiology of premature birth (PTB) impact differently on select neonatal outcomes. We conducted a prospective longitudinal study of 377 singleton preterm neonates [gestational age (GA) at birth: 23-34 weeks] separated into three distinct contemporaneous newborn cohorts: i) spontaneous PTB in the setting of intra-amniotic infection/inflammation (yes-IAI, n = 116); ii) spontaneous PTB in the absence of IAI (no-IAI, n = 130), and iii) iatrogenic PTB for preeclampsia (iPTB-PE, n = 131). Newborns (n = 372) were followed until death or discharge. Amniotic fluid defensins 1&2 and calgranulins A&C were used as biomarkers of IAI. An algorithm considering cord blood interleukin-6 (IL-6) and haptoglobin (Hp switch-on) was used to assess fetal exposure to IAI. Intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), necrotizing enterocolitis (NEC), bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), early-onset neonatal (EONS) and late-onset (LOS) sepsis, death. Independent risk factors for adverse outcomes were: i) IVH (n = 53): histologic chorioamnionitis, GA, fetal growth restriction, male sex, Hp switch-on; ii) PVL (n = 11): cord blood IL-6; iii) NEC (n = 25), GA; iv) BPD (n = 53): ventilator support, need for surfactant, GA; v) ROP (n = 79): ventilator support, Hp switch-on, GA; vi) fetal and neonatal death (n = 31): GA, amniotic fluid IL-6; vii) suspect EONS (n = 92): GA, Hp switch-on; viii) LOS (n = 81): GA. Our findings are applicable to pregnancies delivered between 23 and 34 weeks' gestation in the setting of IAI and PE, and suggest that GA and inflammatory intrauterine environment play key roles in occurrence of IVH, PVL, ROP, death, EONS and LOS. Postnatal determinants seem to play major role in NEC and BPD.

Hepcidin, an Iron Regulatory Hormone of Innate Immunity, is Differentially Expressed in Premature Fetuses with Early-Onset Neonatal Sepsis

OBJECTIVE

Hepcidin, a mediator of innate immunity, binds the iron exporter ferroportin, leading to functional hypoferremia through intracellular iron sequestration. We explored hepcidin-ferroportin interactions in neonates clinically diagnosed with early-onset neonatal sepsis (EONS).

STUDY DESIGN

Hepcidin and interleukin (IL)-6 were quantified by enzyme-linked immunosorbent assay (ELISA) in 92 paired cord blood-maternal blood samples in the following groups: "Yes" EONS (n = 41, gestational age [GA] 29 ± 1 weeks) and "No" EONS (n = 51, GA 26 ± 1 weeks). Placental hepcidin and ferroportin expression were evaluated by immunohistochemistry and real-time-polymerase chain reaction (RT-PCR). Liver hepcidin and ferroportin expression patterns were ascertained in autopsy specimens of neonates (n = 8) who died secondary to culture-proven sepsis.

RESULTS

Cord blood hepcidin was significantly elevated (GA corrected, p = 0.018) and was positively correlated with IL-6 (r = 0.379, p = 0.001) in EONS. Hepcidin localized at syncytiotrophoblast and fetal vascular endothelium. Placental ferroportin, but not hepcidin mRNA correlated with cord blood hepcidin levels (r = 0.46, p = 0.039) and funisitis severity (r = 0.50, p = 0.018). Newborns who died from sepsis (n = 4) had higher hepatic hepcidin and iron sequestration, but lower ferroportin staining than those who died of nonsepsis causes (n = 4).

CONCLUSION

Premature fetuses with EONS have elevated circulating hepcidin, likely related to lower placenta and liver ferroportin expression. Fetal hepcidin-ferroportin interaction appears to play a role in EONS pathophysiology independent of maternal response to intrauterine inflammation.

Maternal sepsis in the era of genomic medicine

PURPOSE

Maternal sepsis remains one of the leading causes of direct and indirect maternal mortality both in high- and low-income environments. In the last two decades, systems biology approaches, based on '-omics' technologies, have started revolutionizing the diagnosis and management of the septic syndrome. The scope of this narrative review is to present an overview of the basic '-omics' technologies, exemplified by cases relevant to maternal sepsis.

METHODS

Narrative review of the new '-omics' technologies based on a detailed review of the literature.

RESULTS

After presenting the main 'omics' technologies, we discuss their limitations and the need for integrated approaches that encompass research efforts across multiple '-omics' layers in the '-omics' cascade between the genome and the phenome.

CONCLUSIONS

Systems biology approaches are revolutionizing the research landscape in maternal sepsis. There is a need for increased awareness, from the side of health practitioners, as a requirement for the effective implementation of the new technologies in the research and clinical practice in maternal sepsis.

Comprehensive RNA profiling of villous trophoblast and decidua basalis in pregnancies complicated by preterm birth following intra-amniotic infection

INTRODUCTION

We performed RNA sequencing with the primary goal of discovering key placental villous trophoblast (VT) and decidua basalis (DB) transcripts differentially expressed in intra-amniotic infection (IAI)-induced preterm birth (PTB).

METHODS

RNA was extracted from 15 paired VT and DB specimens delivered of women with: 1) spontaneous PTB in the setting of amniocentesis-proven IAI and histological chorioamnionitis (n = 5); 2) spontaneous idiopathic PTB (iPTB, n = 5); and 3) physiologic term pregnancy (n = 5). RNA sequencing was performed using the Illumina HiSeq 2500 platform, and a spectrum of computational tools was used for gene prioritization and pathway analyses.

RESULTS

In the VT specimens, 128 unique long transcripts and 7 mature microRNAs differed significantly between pregnancies complicated by IAI relative to iPTB (FDR<0.1). The up-regulated transcripts included many characteristic of myeloblast-derived cells, and bioinformatic analyses revealed enrichment for multiple pathways associated with acute inflammation. In an expanded cohort including additional IAI and iPTB specimens, the expression of three proteins (cathepsin S, lysozyme, and hexokinase 3) and two microRNAs (miR-133a and miR-223) was validated using immunohistochemistry and quantitative PCR, respectively. In the DB specimens, only 11 long transcripts and no microRNAs differed significantly between IAI cases and iPTB controls (FDR<0.1). Comparison of the VT and DB specimens in each clinical scenario revealed signatures distinguishing these placental regions.

DISCUSSION

IAI is associated with a transcriptional signature consistent with acute inflammation in the villous trophoblast. The present findings illuminate novel signaling pathways involved in IAI, and suggest putative therapeutic targets and potential biomarkers associated with this condition.

Diagnostic value of amniotic fluid inflammatory biomarkers for subclinical chorioamnionitis

OBJECTIVE

To determine the value of measuring amniotic fluid inflammatory biomarkers for diagnosis of subclinical chorioamnionitis.

METHODS

A prospective study was conducted among pregnant women with cervical dilation, preterm premature rupture of membranes, threatened late abortion, or threatened premature labor who attended a tertiary care hospital in Guangzhou, China, between June 1, 2012, and January 31, 2014. Participants were divided into two groups according to the presence or absence of subclinical chorioamnionitis. Surface-enhanced laser desorption/ionization time-of-flight mass spectroscopy (SELDI-TOF-MS) was used to detect human neutrophil defensins (HNP-1 and HNP-2), calgranulins A (S100A8), and calgranulins C (S100A12) in amniocentesis samples.

RESULTS

Overall, 22 patients had subclinical chorioamnionitis and 17 patients did not. Positive test results for HNP-2 were noted for more patients with subclinical chorioamnionitis than for those without for HNP-2 (19 [86%] vs 2 [12%]; P<0.001), HNP-1 (19 [86%] vs 5 [29%]; P=0.001), S100A12 (20 [91%] vs 9 [53%]; P=0.011), and S100A8 (12 [55%] vs 0; P<0.001). When three or four of these biomarkers were present, the accuracy for a diagnosis of subclinical chorioamnionitis was 89.7%. The sensitivity, specificity, positive predictive value, and negative predictive value were 81.8%, 100.0%, 100.0%, and 81.0%, respectively.

CONCLUSION

Detection of inflammatory biomarkers in the amniotic fluid by SELDI-TOF-MS exhibited high diagnostic accuracy for subclinical chorioamnionitis.

Novel biomarkers in amniotic fluid for early assessment of intraamniotic infection

Intra-amniotic infection/inflammation (IAI) is associated with preterm birth, short and long-term adverse clinical outcomes and oxidative stress. The diagnosis of IAI is based on histological and clinical findings; however, often these results are unspecific. Therefore, efforts have been directed towards validating reliable methods for patients lacking overt clinical symptoms. In this study, amniotic fluid (AF) samples were prospectively collected from 23 women grouped into two categories (with or without IAI) following clinical, microbiological and histological criteria. AFs were analyzed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) for the determination of the following biomarkers: oxidized and nitrated tyrosines (Tyr), 8-hydroxy-2'-deoxyguanosine (8OHdG), oxidized glutathione (GSSG) and glutathione sulfonamide (GSA). 3-NO2-Tyrosine (3NO2-Tyr) and GSSG concentrations in AF were not identified as significantly relevant biomarkers in the presence of IAI. However, inflammatory biomarkers such as GSA (p=0.002) and 3-Chloro-Tyrosine [3Cl-Tyr (p=0.049)], and oxidative stress biomarker 8OHdG (p=0.021) were significantly increased in AF with IAI as compared to normal controls. Biomarkers of inflammation and oxidative stress determined in AF samples could represent a new approach towards an early diagnosis of IAI and subsequent chorioamnionitis in the clinical setting.

Compartmentalization of acute phase reactants Interleukin-6, C-Reactive Protein and Procalcitonin as biomarkers of intra-amniotic infection and chorioamnionitis

BACKGROUND

The arsenal of maternal and amniotic fluid (AF) immune response to local or systemic infection includes among others the acute-phase reactants IL-6, C-Reactive Protein (CRP) and Procalcitonin (PCT). If these molecules can be used as non-invasive biomarkers of intra-amniotic infection (IAI) in the subclinical phase of the disease remains incompletely known.

METHODS

We used time-matched maternal serum, urine and AF from 100 pregnant women who had an amniocentesis to rule out IAI in the setting of preterm labor, PPROM or systemic inflammatory response (SIR: pyelonephritis, appendicitis, pneumonia) to infection. Cord blood was analyzed in a subgroup of cases. We used sensitive immunoassays to quantify the levels of inflammatory markers in the maternal blood, urine and AF compartment. Microbiological testing and placental pathology was used to establish infection and histological chorioamnionitis.

RESULTS

PCT was not a useful biomarker of IAI in any of the studied compartments. Maternal blood IL-6 and CRP levels were elevated in women with subclinical IAI. Compared to clinically manifest chorioamnionitis group, women with SIR have higher maternal blood IL-6 levels rendering some marginal diagnostic benefit for this condition. Urine was not a useful biological sample for assessment of IAI using either of these three inflammatory biomarkers.

CONCLUSIONS

In women with subclinical IAI, the large overlapping confidence intervals and different cut-offs for the maternal blood levels of IL-6, CRP and PCT likely make interpretation of their absolute values difficult for clinical decision-making.

Use of amniotic fluid for determining pregnancies at risk of preterm birth and for studying diseases of potential environmental etiology

Amniotic fluid (AF) is a biological medium uniquely suited for the study of early exposure of the human fetus to environmental contaminants acquired by the mother before and during pregnancy. Traditional diagnostic applications of AF have focused almost exclusively on the diagnosis of genetic aberrations such as Trisomy-21 and on heritable diseases in high-risk pregnancies. Since more than 50 anthropogenic compounds have been detected in AF, there is considerable potential in utilizing fetal protein biomarkers as indicators of health effects related to prenatal toxic exposure. Here, we focus on preterm birth (PTB) to illustrate opportunities and limitations of using AF as a diagnostic matrix. Representing a pervasive public health challenge worldwide, PTB cannot be managed simply by improving hygiene and broadening access to healthcare. This is illustrated by 15-year increases of PTB in the U.S. from 1989 to 2004. AF is uniquely suited as a matrix for early detection of the association between fetal exposures and PTB due to its fetal origin and the fact that it is sampled from women who are at higher risk of PTB. This critical review shows the occurrence in AF of a number of xenobiotics, including endocrine-disrupting compounds (EDCs), which are known or may reasonably be expected to shorten fetal gestation. It is not yet known whether EDCs, including bisphenol A, phytoestrogens, and polychlorinated biphenyls (PCBs), can affect the expression of proteins considered viable or potential biomarkers for the onset of PTB. As such, the diagnostic value of AF is broad and has not yet been fully explored for prenatal diagnosis of pregnancies at risk from toxic, environmental exposures and for the elucidation of mechanisms underlying important public health challenges including PTB.

Non-invasively collected amniotic fluid as a source of possible biomarkers for premature rupture of membranes investigated by proteomic approach

PURPOSE

Preterm delivery is one of the main causes of perinatal morbidity and mortality and it accounts for 75 % of perinatal mortality and more than half of the long-term morbidity. We applied a proteomic approach based on mass spectrometry (MS) for biomarkers discovery of preterm premature rupture of membranes (pPROM) by investigating amniotic fluid (AF) invasively and non-invasively collected.

METHODS

Amniotic fluid was obtained from vagina of women with pPROM (group 1), PROM at term (group 2) and by genetic amniocentesis (group 3). Pre-fractionated AF proteome was analyzed through matrix assisted laser desorption ionization-time of flight (MALDI-TOF) MS. The characterization of proteins/peptides of interest was obtained by high performance liquid chromatography-electrospray tandem MS.

RESULTS

Three peptides overexpressed in pPROM and able to discriminate the groups 1 and 2 were detected. One peptide was identified as the fragment Gly452LAVPDGPLGLPPKPro466 of the protein KIAA1522, expressed by fetal brain and liver. This peptide was overexpressed in a patient of the group 3, completely asymptomatic at the time of the amniocentesis, who later developed pPROM.

CONCLUSION

Amniotic fluid invasively and non-invasively collected can be analyzed by MALDI-TOF MS to obtain proteomic profiles. Proteomic analysis identified a peptide with promising diagnostic capability for pPROM.

Amniotic fluid: the use of high-dimensional biology to understand fetal well-being

Our aim was to review the use of high-dimensional biology techniques, specifically transcriptomics, proteomics, and metabolomics, in amniotic fluid to elucidate the mechanisms behind preterm birth or assessment of fetal development. We performed a comprehensive MEDLINE literature search on the use of transcriptomic, proteomic, and metabolomic technologies for amniotic fluid analysis. All abstracts were reviewed for pertinence to preterm birth or fetal maturation in human subjects. Nineteen articles qualified for inclusion. Most articles described the discovery of biomarker candidates, but few larger, multicenter replication or validation studies have been done. We conclude that the use of high-dimensional systems biology techniques to analyze amniotic fluid has significant potential to elucidate the mechanisms of preterm birth and fetal maturation. However, further multicenter collaborative efforts are needed to replicate and validate candidate biomarkers before they can become useful tools for clinical practice. Ideally, amniotic fluid biomarkers should be translated to a noninvasive test performed in maternal serum or urine.

Comparative microbial analysis of paired amniotic fluid and cord blood from pregnancies complicated by preterm birth and early-onset neonatal sepsis

BACKGROUND

16S rRNA-based genomic analyses have revolutionized our understanding of infectious diseases. Many cases which were recognized as "idiopathic" are now known to have an infectious etiology. Here, we present a proof-of-concept study to examine the microbial link between intra-amniotic infection (IAI) and early-onset neonatal sepsis (EONS).

RESULTS

Using culture independent methods, we analyzed paired amniotic fluid (AF) and cord blood (CB) samples from 36 singleton pregnancies complicated by preterm birth (PTB), IAI, and/or EONS. PTB cases were grouped as 1) Group 1- neonatal blood culture-positive EONS (n=6). 2) Group 2- neonatal blood culture-negative presumed EONS with positive IAI (n=16). 3) Group 3- neonatal blood culture-negative presumed EONS with no IAI (n=7); 4) Group 4- no EONS or IAI (n=7). In addition, samples from term healthy deliveries (n=8) served as technical controls. A total of 31 species (15 non-redundant) were identified in AF, of which only 1/3 were cultivated. Significantly fewer microorganisms were detected in CB, with a total of 18 species (7 non-redundant) identified, of which only 2 (Escherichia coli, Streptococcus agalactiae) were cultivated. Of those, Bergeyella, Fusobacterium nucleatum, and Sneathia sanguinegens had not been detected in EONS before. The novel species identified in AF by PCR include Peptoniphilus harei and Lachnospiraceae sp. The majority (72%) of CB species were also detected in the matching AF, with E. coli and F. nucleatum as the most prevalent. The 16S rRNA sequences of paired AF and CB were 99.9-100% identical, while no identical sequences were found between different pregnancies.

CONCLUSIONS

Previously unrecognized, uncultivated or difficult-to-cultivate species are implicated in EONS. Microbial species in paired AF and CB likely share the same infectious origin. Given its prevalence in EONS, F. nucleatum should be placed on the same importance scale as E. coli.

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.