Potential Peripartum Markers of Infectious-Inflammatory Complications in Spontaneous Preterm Birth

Correlation of amniotic fluid inflammatory markers with preterm birth: a meta-analysis

BACKGROUND

The relationship between amniotic fluid inflammatory biomarkers and preterm birth in second- or third-trimester pregnancy has been a focus, and understanding the correlation between these markers and preterm birth is important for early identification and intervention in preterm birth. The aim of this study was to explore potential inflammatory biomarkers in second- or third-trimester pregnancy amniotic fluid associated with preterm birth.

METHODS

On November 30, 2023, we searched literature involved the influence of second- or third-trimester pregnancy amniotic fluid inflammatory biomarkers on preterm birth through PubMed, Web of Science, Embase, Scope, CNKI, WanFang, VIP and China Biomedical Databases. The search languages were Chinese and English. Included outcomes indexes were combined utility analysis via R software.

RESULTS

A total of 11 articles were included in the combined utility analysis. This combined analysis revealed significant differences in several inflammatory biomarkers in amniotic fluid between the two groups (MD = 6.87, 95%CI: 0.26 - 13.47, P < 0.01); the difference in amniotic fluid IL-6 between the two groups (MD = 5.73, 95%CI: 3.13-8.32, P < 0.01); the difference in amniotic fluid IL-10 between the two groups (MD = 0.11, 95%CI: -3.26-3.48, P < 0.01); the difference in amniotic fluid CRP between the two groups (MD = 21.34, 95%CI: 11.69-30.89, P < 0.01); the difference in amniotic fluid MCP-1 between the two groups (MD = 312.14, 95%CI: 211.34-412.97, P < 0.01); the difference in the amniotic fluid MMP-9 between the two groups (MD = 0.86, 95%CI: -0.10-1.82, P < 0.01); and the difference in TNF-α in amniotic fluid between the two groups (MD = 22.78, 95%CI: -5.05-50.61, P < 0.01).

CONCLUSIONS

The inflammatory biomarkers IL-1β, IL-6, IL-10, CRP, TNFα, MCP-1 and MMP-9 in the amniotic fluid of patients in the second- or third-trimester pregnancy were all correlated with preterm birth.

Amniotic fluid CD36 in pregnancies complicated by spontaneous preterm delivery: a retrospective cohort study

OBJECTIVE

The aim of this study was to evaluate CD36 concentrations in amniotic fluid in pregnancies complicated by spontaneous delivery with intact fetal membranes (preterm labor, PTL) and preterm prelabor rupture of membranes (PPROM) with respect to the presence of the intra-amniotic infection.

METHODS

A total of 80 women with PPROM and 71 with PTL were included in the study. Amniotic fluid samples were obtained by transabdominal amniocentesis. Amniotic fluid CD36 concentrations were assessed by enzyme-linked immunosorbent assay. Microbial colonization of the amniotic cavity (MIAC) was determined by the cultivation and non-cultivation approach. Intra-amniotic inflammation (IAI) was defined as an amniotic fluid bedside interleukin-6 concentration ≥3000 pg/mL. Intra-amniotic infection was characterized by the presence of both MIAC and IAI.

RESULTS

Women with PPROM with intra-amniotic infection had higher amniotic fluid CD36 concentrations than women without infection (with infection: median 346 pg/mL, IQR 262-384 vs. without infection: median 242 pg/mL, IQR 199-304; p = .006) A positive correlation between amniotic fluid CD36 concentrations and interleukin-6 concentrations was found (rho = 0.48; p < .0001). In PTL pregnancies, no statistically significant difference was found in the amniotic fluid level of CD36 between intra-amniotic infection, sterile IAI, and negative amniotic fluid.

CONCLUSIONS

The presence of intra-amniotic infection is characterized by higher amniotic fluid CD36 concentrations in pregnancies complicated by PPROM. An amniotic fluid CD36 cutoff value of 252.5 pg/mL was found to be optimal for the prediction of intra-amniotic infection. In PTL pregnancies, no statistically significant change in CD36 concentration was found with respect to the presence of intra-amniotic infection.

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.

IgGFc-binding protein in pregnancies complicated by spontaneous preterm delivery: a retrospective cohort study

To determine the IgGFc-binding protein (FcgammaBP) concentration in amniotic and cervical fluids in preterm prelabor rupture of membranes (PPROM) and preterm labor with intact membranes (PTL) and to assess the diagnostic indices of FcgammaBP to predict intra-amniotic infection (the presence of both microbial invasion of the amniotic cavity and intra-amniotic inflammation). In this study, we included 170 and 79 women with PPROM and PTL, respectively. Paired cervical and amniotic fluid samples were obtained using a Dacron polyester swab and transabdominal amniocentesis, respectively. The FcgammaBP concentrations in the samples were assessed using an enzyme-linked immunosorbent assay. The presence of intra-amniotic infection was associated with elevated FcgammaBP concentrations in pregnancies with PPROM and PTL [PPROM—presence: 86 ng/mL vs. absence: 13 ng/mL, p < 0.0001, area under receiver operating characteristic curve (AUC) = 0.94; PTL—presence: 140 ng/mL vs. absence: 22 ng/mL, p < 0.0001, AUC = 0.86]. In cervical fluid, the concentrations of FcgammaBP were elevated in the presence of intra-amniotic infection in pregnancies with PPROM only (presence: 345 ng/mL vs. absence: 60 ng/mL, p < 0.0001, AUC = 0.93). FcgammaBP in amniotic fluid might be a marker of intra-amniotic infection in women with both PPROM and PTL However, in cervical fluid, it is only observed in women with PPROM.

The role of maternal infection in preterm birth: evidence from the Brazilian Multicentre Study on Preterm Birth (EMIP)

OBJECTIVES

Evidence suggests that infection or inflammation is a major contributor to early spontaneous preterm birth (sPTB). Therefore, this study aimed to investigate the development and causes of maternal infection associated with maternal and neonatal outcomes in women with sPTB.

METHODS

This was a secondary analysis of a multicenter cross-sectional study with a nested case-control component, the Brazilian Multicentre Study on Preterm Birth (EMIP), conducted from April 2011 to July 2012 in 20 Brazilian referral obstetric hospitals. Women with preterm birth (PTB) and their neonates were enrolled. In this analysis, 2,682 women undergoing spontaneous preterm labor and premature pre-labor rupture of membranes were included. Two groups were identified based on self-reports or prenatal or hospital records: women with at least one infection factor and women without any maternal infection (vulvovaginitis, urinary tract infection, or dental infection). A bivariate analysis was performed to identify potential individual risk factors for PTB. The odds ratios (ORs) with their respective 95% confidence intervals were calculated.

RESULTS

The majority of women with sPTB fulfilled at least one criterion for the identification of maternal infection (65.9%), and more than half reported having urinary tract infection during pregnancy. Approximately 9.6% of women with PTB and maternal infection were classified as having periodontal infection only. Apart from the presence of a partner, which was more common among women with infectious diseases (p=0.026; OR, 1.28 [1.03-1.59]), other variables did not show any significant difference between groups.

CONCLUSION

Maternal infection was highly prevalent in all cases of sPTBs, although it was not clearly associated with the type of PTB, gestational age, or any adverse neonatal outcomes.

Nicotinamide phosphoribosyltransferase and intra-amniotic inflammation in preterm prelabor rupture of membranes

Introduction: The amniotic fluid nicotinamide phosphoribosyltransferase (NAMPT) levels have not been compared among women with preterm prelabor rupture of membranes (PPROM) comorbid with intra-amniotic infection, sterile intra-amniotic inflammation (IAI), colonization, or without IAI and microbial invasion of the amniotic cavity (MIAC). Therefore, the main aim was to quantify the amniotic fluid NAMPT in women with PPROM complicated by intra-amniotic infection, sterile IAI, or colonization. The second aim was to characterize the diagnostic indices of NAMPT to reveal IAI. The third aim was to determine whether the cervical fluid and maternal serum NAMPT quantitation might be of value in the identification of intra-amniotic inflammatory complications in PPROM.Methods of study: NAMPT levels in amniotic fluid, cervical fluid, and maternal serum were assessed in three independent cohorts of women with singleton pregnancies complicated by PPROM between 24⁺⁰ and 36⁺⁶ weeks of gestation consisting of 88, 121, and 88 women, respectively. Amniotic fluid samples were obtained by transabdominal amniocentesis, cervical fluid samples were obtained using a Dacron polyester swab and maternal blood was obtained by venipuncture of the cubital vein. The NAMPT levels were measured by an enzyme-linked immunosorbent assay. Testing for MIAC and IAI was performed on all women, who were then categorized into four subgroups: intra-amniotic infection (MIAC and IAI), sterile IAI (IAI alone), colonization (MIAC alone), and without MIAC and IAI.Results: Women with intra-amniotic infection and women with sterile IAI had higher NAMPT levels than did women with colonization and women without MIAC and IAI (intra-amniotic infection: median 73.6 ng/mL, sterile IAI: median 55.5 ng/mL, colonization: median 12.1 ng/mL, without MIAC and IAI: 10.6 ng/mL; p < .0001). An amniotic fluid NAMPT level of 37 ng/mL was the best value for the detection of intra-amniotic infection in women with PPROM. Cervical fluid (p = .51) and maternal serum (p = .50) NAMPT levels did not reflect intra-amniotic inflammatory complications in women with PPROM.Conclusions: Intra-amniotic infection and sterile IAI are associated with higher NAMPT levels in amniotic fluid but not in cervical fluid or maternal serum in women with PPROM. Amniotic fluid NAMPT might be a marker for invasive identification of IAI in PPROM.

The microbiome during pregnancy and early postnatal life

We are changing our concept that the newborn infant emerges from a sterile environment. In-utero colonization may have major impacts on the developing mammal in terms of development of immunity and metabolism that, with epigenetic modifications, will lead to diseases in later life. In addition, the microbial profile that develops during and after birth depends on mode of delivery, type of feeding (human milk versus formula) and various other environmental factors to which the newborn is exposed. The goal of this review is to clarify that the microbiome in the maternal fetal unit as well as the immediate changes that occur as new microbes are acquired postnatally play major roles in subsequent health and disease. Rapidly developing technologies for multi-omic analyses and systems biology are shifting paradigms in both scientific knowledge and clinical care.

Amniotic fluid calreticulin in pregnancies complicated by the preterm prelabor rupture of membranes

OBJECTIVE

This study aimed to determine the amniotic fluid calreticulin concentrations in women with the preterm prelabor rupture of membranes (PPROM) based on the microbial invasion of the amniotic cavity (MIAC), intraamniotic inflammation (IAI) and microbial-associated IAI.

METHODS

One hundred sixty-eight women with singleton pregnancies were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis and were assayed for calreticulin concentrations by ELISA. IAI was defined as an amniotic fluid interleukin-6 concentration > 745 pg/ml. Microbial-associated IAI was defined as the presence of both MIAC and IAI.

RESULT

Women with MIAC (with MIAC: median 54.4 ng/ml, versus without MIAC: median 32.6 ng/ml; p < 0.0001), IAI (with IAI: median 66.8 ng/ml, versus without IAI: median 33.0 ng/ml; p < 0.0001) and microbial-associated IAI (with microbial-associated IAI: median 82.5 ng/ml, versus without microbial-associated IAI: median 33.7 ng/ml; p < 0.0001) had higher concentrations of calreticulin than women without these complications. An amniotic fluid calreticulin concentration of 81.4 ng/ml was found to be the best cutoff point for identifying women with microbial-associated IAI.

CONCLUSIONS

The presence of microbial-associated IAI is associated with increased amniotic fluid calreticulin concentrations. Calreticulin seems to be a promising marker for the early identification of PPROM complicated by microbial-associated IAI.

Visfatin: New marker of oxidative stress in preterm newborns

BACKGROUND

Oxidative stress is involved in several neonatal conditions characterized by an upregulation in the production of oxidative or nitrative free radicals and a concomitant decrease in the availability of antioxidant species. Oxygen, which is obviously vital to survival, can be highly damaging to neonatal tissue which is known to be poorly equipped to neutralize toxic derivatives. Thus, exposure of the newborn infant to high oxygen concentrations during resuscitation at birth increases oxidative damage. Visfatin is an adipocytokine involved in oxidative stress and an important mediator of inflammation that induces dose-dependent production of both pro-inflammatory and anti-inflammatory cytokines. To our knowledge, the diagnostic value of visfatin as a marker of oxidative stress in preterm newborns has not been investigated.

OBJECTIVE

The aim of this study was to evaluate visfatin levels in preterm neonates resuscitated with different concentrations of oxygen in the delivery room.

PATIENTS

Fifty-two preterm newborns with gestational age less than 32 weeks, resuscitated randomly with different oxygen concentrations (40%, 60%, or 100%) were enrolled at the University Hospital of Messina, over a 12-month period to evaluate serum visfatin levels at T0 (within 1 h after birth), T24 h, T72 h, and T168 h of life.

RESULTS

At T72 h and T168 h, higher serum visfatin values in the high-oxygen group compared to the low- and mild-oxygen subjects (P=0.002 and P<0.001, respectively) were noted.

CONCLUSION

The results of this study suggest that visfatin could be a new marker of oxidative stress in preterm newborns.