Second-trimester amniotic fluid interleukin-10 concentration predicts preterm delivery

Cytokines and pregnancy: Potential regulation by histone deacetylases

Cytokines are important regulators of pregnancy and parturition. Aberrant expression of proinflammatory cytokines during pregnancy contributes towards preterm labor, pre-eclampsia, and gestational diabetes mellitus. The regulation of cytokine expression in human cells is highly complex, involving interactions between environment, transcription factors, and feedback mechanisms. Recent developments in epigenetic research have made tremendous advancements in exploring histone modifications as a key epigenetic regulator of cytokine expression and the effect of their signaling molecules on various organ systems in the human body. Histone acetylation and subsequent deacetylation by histone deacetylases (HDACs) are major epigenetic regulators of protein expression in the human body. The expression of various proinflammatory cytokines, their role in normal and abnormal pregnancy, and their epigenetic regulation via HDACs will be discussed in this review.

Interleukin 8 may predict surgical necrotizing enterocolitis in infants born less than 1500 g

Necrotizing enterocolitis (NEC) often leads to gastrointestinal emergency resulting high mortality in very low birth weight infants (VLBWIs) requiring surgery. To date, few studies have explored the role of serum cytokines in the development of feeding intolerance (FI) or NEC outcomes in VLBWIs. Infants born weighing <1500 g or of 32 weeks of gestational age were prospectively enrolled from May 2018 to Dec 2019. We measured several cytokines routinely within 72 h of life, even before NEC-like symptoms developed. NEC or FI group comprised 17 (27.4%) infants, and 6 (9.7%) infants had surgical NEC. The gestational age and birth weight were significantly lower in the NEC or FI group with more prematurity-related complications. The surgical NEC group also demonstrated significantly lower gestational age and birth weight along with more infants experiencing refractory hypotension within a 1 week of life, pulmonary hypertension, and patent ductus arteriosus. IL-10 levels were significantly higher in the NEC or FI group, whereas IL-8 levels were significantly higher in the infants with surgical NEC. Our findings indicated to IL-8 can predict surgical NEC while increased IL-10 can predict NEC development in VLBWIs.

Protein Concentrations of Thrombospondin-1, MIP-1β, and S100A8 Suggest the Reflection of a Pregnancy Clock in Mid-Trimester Amniotic Fluid

The development of immunoassays enables more sophisticated studies of the associations between protein concentrations and pregnancy outcomes, allowing early biomarker identification that can improve neonatal outcomes. The aim of this study was to explore associations between selected mid-trimester amniotic fluid proteins and (1) overall gestational duration and (2) spontaneous preterm delivery. A prospective cohort study, including women undergoing mid-trimester transabdominal genetic amniocentesis, was performed in Gothenburg, Sweden, 2008-2016 (n = 1072). A panel of 27 proteins related to inflammation was analyzed using Meso-Scale multiplex technology. Concentrations were adjusted for gestational age at sampling, experimental factors, year of sampling, and covariates (maternal age at sampling, parity (nulliparous/multiparous), smoking at first prenatal visit, and in vitro fertilization). Cox regression analysis of the entire cohort was performed to explore possible associations between protein concentrations and gestational duration. This was followed by Cox regression analysis censored at 259 days or longer, to investigate whether associations were detectable in women with spontaneous preterm delivery (n = 47). Finally, linear regression models were performed to analyze associations between protein concentrations and gestational duration in women with spontaneous onset of labor at term (n = 784). HMG-1, IGFBP-1, IL-18, MIP-1α, MIP-1β, S100A8, and thrombospondin-1 were significantly associated with gestational duration at term, but not preterm. Increased concentrations of thrombospondin-1, MIP-1β, and S100A8, respectively, were significantly associated with decreased gestational duration after the Holm-Bonferroni correction in women with spontaneous onset of labor at term. This adds to the concept of a pregnancy clock, where our findings suggest that such a clock is also reflected in the amniotic fluid at early mid-trimester, but further research is needed to confirm this.

Cell-Free DNA Release by Mouse Fetal Membranes

INTRODUCTION

Cell-free "fetal" DNA is released from the placenta. Because the fetal membranes also arise from the trophectoderm layer of the blastocyst, these studies sought to test the hypothesis that the membranes also release cell-free DNA (cfDNA).

METHODS

Fetal membranes were harvested from pregnant CD-1 mice and cultured in 12-well plates containing media alone or with staurosporine and thapsigargin (apoptosis stimulators), Q-VD-OPh (caspase inhibitor), Trolox (vitamin E analog), and lipopolysaccharide and tumor necrosis factor α (TNFα; inflammatory mediators). The cfDNA in the media was extracted, quantified, and normalized for tissue weight. Media was used for a lactate dehydrogenase (LDH) assay. Membrane homogenates were used to assess activated caspase levels and the expression of DNA fragmentation factor B (DFFB) and BAX proteins. 5-Methylcytosine was assessed using a 5-mC DNA enzyme-linked immunosorbent assay. The cfDNA was used to stimulate interleukin 6 (IL6) release by J774A.1 mouse macrophage cells.

RESULTS

Increased cfDNA release at 6 and 21 hours occurred in parallel with increasing LDH levels. The cfDNA concentrations were significantly suppressed by Q-VD-OPh and Trolox and increased by thapsigargin and TNFα. Increased caspase activity was suppressed by Q-VD-OPh and increased by TNFα, thapsigargin, and staurosporine. The expression of BAX and DFFB proteins significantly increased by 21 hours. 5-Methylcytosine levels were significantly lower in fetal membranes and placentas and below detectable in the cfDNA released by the explants. The cfDNA-stimulated IL6 release by macrophage cells was suppressed by chloroquine, a Toll-like receptor 9 (TLR9) inhibitor.

CONCLUSIONS

These studies have confirmed cfDNA release by the mouse fetal membranes; cfDNA was markedly hypomethylated and a robust stimulator of TLR9.

The association between selected mid-trimester amniotic fluid candidate proteins and spontaneous preterm delivery

Objective: The aim of this study was to explore inflammatory response and identify early potential biomarkers in mid-trimester amniotic fluid associated with subsequent spontaneous preterm delivery (PTD).Methods: A cohort study was performed at Sahlgrenska University Hospital/Östra, Gothenburg, Sweden, between 2008 and 2010. Amniotic fluid was collected from consecutive women undergoing mid-trimester transabdominal genetic amniocentesis at 14-19 gestational weeks. Clinical data and delivery outcome variables were obtained from medical records. The analysis included 19 women with spontaneous PTD and 118 women who delivered at term. A panel of 26 candidate proteins was analyzed using Luminex xMAP technology. Candidate protein concentrations were analyzed with ANCOVA and adjusted for plate effects.Results: The median gestational age at delivery was 35 + 3 weeks in women with spontaneous PTD and 40 + 0 weeks in women who delivered at term. Nominally significantly lower amniotic fluid levels of adiponectin (PTD: median 130,695 pg/mL (IQR 71,852-199,414) vs term: median 185,329 pg/mL (IQR (135,815-290,532)), granulocyte-macrophage colony stimulating factor (PTD: median 137 pg/mL (IQR 74-156) vs term: median 176 pg/mL (IQR 111-262)), and macrophage migration inhibitory factor (PTD: median 3025 pg/mL (IQR 1885-3891) vs term: median 3400 pg/mL (IQR 2181-5231)) were observed in the spontaneous PTD group, compared with the term delivery group, after adjusting for plate effects. No significant differences remained after Bonferroni correction for multiple comparisons.Conclusions: Our results are important in the process of determining the etiology behind spontaneous PTD but due to the non-significance after Bonferroni correction, the results should be interpreted with caution. Further analyses of larger sample size will be required to determine whether these results are cogent and to examine whether microbial invasion of the amniotic cavity or intra-amniotic inflammation occurs in asymptomatic women in the mid-trimester with subsequent spontaneous PTD.

Procalcitonin in amniotic fluid at the time of genetic amniocentesis and preterm delivery

PURPOSE

Procalcitonin (PCT) is an acute-phase protein that has been infrequently studied in amniotic fluid. We sought to determine if PCT levels measured in amniotic fluid samples at the time of genetic amniocentesis are predictive of preterm delivery.

MATERIALS AND METHODS

A retrospective cohort study was performed on all women presenting for genetic amniocentesis between 15-23 weeks of pregnancy at our institution from 2011 to 2013 with stored amniotic fluid samples. PCT protein levels were measured in the samples by enzyme-linked immunosorbent assay (ELISA). PCT levels in women who delivered less than 37 weeks versus those who delivered at or after 37 week were compared. Mann-Whitney test was used.

RESULTS

Eighty-seven samples were available for analysis and of these eight (9.2%) were from patients who delivered preterm. Sixty-two (70%) had PCT levels below the lower limit of quantification, which was 25 pg/mL. Median PCT levels did not differ between the preterm and term group [20.4 pg/mL (range 0-82.8) and 20.2 pg/mL (range 0-198.4), respectively, p = .95].

CONCLUSION

In asymptomatic women undergoing genetic amniocentesis in this cohort, procalcitonin levels were low to undetectable and did not correlate with risk of subsequent preterm birth.

Early- or mid-trimester amniocentesis biomarkers for predicting preterm delivery: a meta-analysis

OBJECTIVE

To determine the value of early- or mid-trimester amniotic fluid levels of interleukin-6 (IL-6), matrix metalloproteinase-8 (MMP-8), and glucose for predicting preterm delivery.

METHODS

Randomized controlled trials and two-arm prospective, retrospective, cohorts, and case-controlled studies in which patients received early- or mid-trimester amniocentesis for karyotyping, and biomarker testing of the amniotic fluid was performed and delivery data were available were included in the analysis.

RESULTS

Outcome measures were the associations of amniotic fluid IL-6, MMP-8, and glucose levels with preterm delivery. Differences in means with 95% confidence intervals (CIs) were calculated. Of 288 articles identified, 14 were included in the meta-analysis with a total of 675 patients who had preterm birth and 2518 patients who had term births. The preterm-delivery group had significantly higher amniotic fluid IL-6 and MMP-8 levels, and a significantly lower glucose level than the term delivery group (IL-6: difference in means = 0.32, 95% CI: 0.22-0.43, p < 0.001; MMP-8: difference in means = 4.47, 95% CI: 0.83-8.11), p = 0.016; glucose: difference in means = -5.22, 95% CI: -8.19 to -2.26, p = 0.001) Conclusion: Early- or mid-trimester amniotic fluid IL-6, MMP-8, and glucose levels are useful for predicting the risk of preterm delivery. KEY MESSAGES Median amniotic fluid ferritin and IL-6 levels, and mean amniotic fluid ALP levels were higher in the preterm group. The preterm-delivery group had significantly higher amniotic fluid IL-6 and MMP-8 levels, and a significantly lower glucose level than the term-delivery group.

Cell-Free Fetal DNA, Telomeres, and the Spontaneous Onset of Parturition

Multiple previous reports have provided compelling support for the premise that spontaneous parturition is mediated by activation of inflammation-related signaling pathways leading to increased secretion of cytokines and chemokines, the influx of neutrophils and macrophages into the pregnant uterus, increased production of uterine activation proteins (eg, connexin-43, cyclo-oxygenase-2, oxytocin receptors, etc), activation of matrix metalloproteinases, and the release of uterotonins leading to cervical ripening, membrane rupture, and myometrial contractions. The missing link has been the fetal/placental signal that triggers these proinflammatory events in the absence of microbial invasion and intrauterine infection. This article reviews the biomedical literature regarding the increase in cell-free fetal DNA (cffDNA), which is released during apoptosis in the placenta and fetal membranes at term, the ability of apoptosis modified vertebrate DNA to stimulate toll-like receptor-9 (TLR9) leading to increased release of cytokines and chemokines, and the potential "fail-safe" role for the anti-inflammatory cytokine IL-10. This article also reviews the literature supporting the key role that telomere loss plays in regard to increasing the ability of vertebrate (including placental) DNA to stimulate TLR9, and in regard to signaling the onset of apoptosis in the placenta and fetal membranes, thereby providing a biologic clock that determines the length of gestation and the timing for the onset of parturition. In summary, this literature review provides a strong rationale for future research to test the hypothesis that telomere loss and increased cffDNA levels trigger the proinflammatory events leading to the spontaneous onset of parturition in mammals: the "cffDNA/telomere hypothesis."

Identification of biomarkers for preterm delivery in mid-trimester amniotic fluid

OBJECTIVE

We investigated whether the level of vascular endothelial growth factor (VEGF) and inflammatory markers in mid-trimester amniotic fluid have predictive value for spontaneous preterm birth in singleton pregnancy.

METHOD

Our subjects were 72 pregnant women who were undertaken with amniocentesis from 16 to 19 weeks of gestation. 36 cases were women with preterm delivery, and other 36 cases were matched women with full-term delivery. Stored amniotic fluid was investigated after the delivery. The levels of matrix metalloproteinases-8 (MMP-8), interleukin-6 (IL-6), C-reactive protein (CRP), and VEGF were measured by enzyme-linked immunosorbent assay (ELISA) and Western blot.

RESULTS

The levels of MMP-8 and IL-6 in preterm group were significantly higher than control group (5.76 ± 1.53 ng/ml vs 4.89 ± 1.77 ng/ml and 170.54 ± 55.69 pg/ml vs 141.92 ± 57.21 pg/ml, respectively) (p < 0.05). In terms of VEGF, the levels were elevated in preterm group (30.76 ± 4.06 pg/ml vs 22.36 ± 7.03 pg/ml) (p < 0.05).

CONCLUSION

This study suggests that elevated levels of IL-6 and MMP-8 in amniotic fluid at mid-trimester are predictive of preterm delivery, and that VEGF which is representative of angiogenesis can be a new and useful predictor of preterm delivery.

Postnatal amniotic fluid intake reduces gut inflammatory responses and necrotizing enterocolitis in preterm neonates

Preterm neonates are susceptible to gastrointestinal disorders such as necrotizing enterocolitis (NEC). Maternal milk and colostrum protects against NEC via growth promoting, immunomodulatory, and antimicrobial factors. The fetal enteral diet amniotic fluid (AF), contains similar components, and we hypothesized that postnatal AF administration reduces inflammatory responses and NEC in preterm neonates. Preterm pigs (92% gestation) were delivered by caesarean section and fed parental nutrition (2 days) followed by enteral (2 days) porcine colostrum (COLOS, n = 7), infant formula (FORM, n = 13), or AF supplied before and after introduction of formula (AF, n = 10) in experiment 1, and supplied only during the enteral feeding period in experiment 2 (FORM, n = 16; AF, n = 14). The NEC score was reduced in both AF and COLOS pigs, relative to FORM, when AF was provided prior to full enteral feeding (9.9 and 7.7 compared with 17.3, P < 0.05). There was no effect of AF when provided only during enteral feeding. AF pigs showed decreased bacterial abundance in colon and intestinal inflammation-related genes (e.g., TNF-α, IL-1α, IL-6, NOS) were downregulated, relative to FORM pigs with NEC. Anti-inflammatory properties of AF were supported by delayed maturation and decreased TNF-α production in murine dendritic cells, as well as increased proliferation and migration, and downregulation of IL-6 expression in intestinal cells (IEC-6, IPEC-J2). Like colostrum, AF may reduce NEC development in preterm neonates by suppressing the proinflammatory responses to enteral formula feeding and gut colonization when provided before the onset of NEC.

Interleukin-10 predicts preterm birth in acculturated Hispanics

OBJECTIVE

Among Hispanics living in the United States, acculturation is associated with an increased risk for preterm birth. Inflammatory pathways are also associated with preterm birth. As such, the current study sought to investigate the potential relationships among preterm birth, acculturation of Hispanic women, and inflammatory markers.

STUDY DESIGN

The authors performed an observational study on pregnant Hispanic women in Texas at 22-24 weeks' gestation (n = 470). The authors obtained demographic data prenatally as well as birth outcome data from the medical chart after delivery. The authors obtained venous blood and used plasma to assay interleukin-1 receptor antagonist (IL-1RA), interleukin-6 (IL-6), and interleukin-10 (IL-10). The authors used logistic regression to understand whether the presence or the absence of IL-10 levels was related to acculturation and the risk of preterm birth.

RESULTS

The authors observed interactions between undetectable IL-10 levels and years in the United States and undetectable IL-10 levels and being born in the United States in models predicting preterm birth. Follow-up probes of these interactions suggested that when IL-10 was undetectable, preterm birth became more likely as time living in the United States increased, χ(2) = 5.15 (1, 416), p = .020, odds ratio (OR) = 3.17, and was more likely in participants born in the United States than in those born elsewhere, χ(2) = 5.35 (1, 462), p = .020, OR = 16.78. The authors observed no interactions among acculturation, preterm birth, and IL-1RA and IL-6 levels.

CONCLUSION

Acculturated Hispanics who lack the protective effects of IL-10 experience a markedly higher risk of preterm birth than nonacculturated Hispanics.

Effects of amniotic and maternal CD-146, TGF-β1, IL-12, IL-18 and IFN-γ, on adverse pregnancy outcome

OBJECTIVE

Our aim was to determine the effects of maternal serum and amniotic fluid levels of cluster of differentiation 146 (CD-146), transforming growth factor (TGF)-β1, interleukin (IL)-12, IL-18, and interferon (IFN)-γ on intrauterine growth restriction and preterm labor.

METHODS

In this retrospective cohort study, we included pregnant women who underwent amniocentesis at Istanbul University Cerrahpasa Medical School. Women were followed up to labor. The study group comprised 23 women with adverse pregnancy outcomes (intrauterine growth restriction and preterm labor), and the control group comprised 105 women with normal pregnancy outcome.

RESULTS

The study group was further divided into two subgroups of preterm labor and intrauterine growth restriction. No significant differences were found for IL-12, IFN-γ, TGF-β1, or CD-146 levels in either plasma or amniotic fluid between the study and control groups. Serum IL-18 levels were similar, but the amniotic fluid level of IL-18 was significantly higher in the intrauterine growth restriction subgroup than that in the preterm labor subgroup and that in the control group (p < 0.01).

CONCLUSIONS

Increased IL-18 level in amniotic fluid may be a predictor for intrauterine growth restriction. IL-12, IFN-γ, TGF-β1, and CD-146 were not related to adverse pregnancy outcome.

Midtrimester amniotic fluid concentrations of interleukin-6 and interferon-gamma-inducible protein-10: evidence for heterogeneity of intra-amniotic inflammation and associations with spontaneous early (<32 weeks) and late (>32 weeks) preterm delivery

INTRODUCTION

Intra-amniotic inflammation is traditionally defined as an elevation of amniotic fluid interleukin (IL)-6. Previous case control studies have suggested an association between an elevated midtrimester amniotic fluid IL-6 and preterm delivery, although such an association has been recently challenged. Intra-amniotic inflammation can also be defined by an elevation of the T-cell chemokine, Interferon-gamma-inducible protein (IP)-10. An elevation in amniotic fluid IP-10 has been associated with chronic chorioamnionitis, a lesion frequently found in late spontaneous preterm birth and fetal death. In contrast, an elevation in amniotic fluid IL-6 is typically associated with acute chorioamnionitis and funisitis. This study was conducted to examine the relationship between an elevation in amniotic fluid IL-6 in the midtrimester and preterm delivery at or before 32 weeks of gestation, and the amniotic fluid concentration of IP-10 and preterm delivery after 32 weeks of gestation.

MATERIALS AND METHODS

This cohort study included 847 consecutive women undergoing genetic midtrimester amniocentesis; in 796 cases, amniotic fluid and pregnancy outcome was available for study after exclusion of abnormal karyotype and/or fetal congenital anomalies. Spontaneous preterm delivery was defined as early (≤32 weeks) or late (after 32 completed weeks of pregnancy). The amniotic fluid and maternal blood concentrations of IL-6 and IP-10 were measured by specific immunoassays.

RESULTS

1) The prevalence of preterm delivery was 8.3% (66/796), while those of early and late spontaneous preterm delivery were 1.5% (n=12), and 4.5% (n=36), respectively; 2) patients who had a spontaneous preterm delivery after 32 weeks of gestation had a higher median amniotic fluid IP-10 concentration than those who delivered at term [median 713 pg/mL, inter-quartile range (IQR) 509-1427 pg/mL vs. median 589 pg/mL, IQR 402-953 pg/mL; P=0.006] and an elevation of amniotic fluid IP-10 concentration above 502 pg/mL (derived from an ROC curve) was associated with late spontaneous preterm delivery [odds ratio 3.9 (95% CI 1.6-9.9)]; 3) patients who had a spontaneous preterm delivery ≤32 weeks of gestation had a higher median amniotic fluid IL-6 concentration than those who delivered at term [median 2052 pg/mL, IQR 435-3015 pg/mL vs. median 414 pg/mL, IQR 209-930 pg/mL; P=0.006], and an elevated amniotic fluid IL-6 concentration above 1740 pg/mL (derived from an ROC curve) was associated with early spontaneous preterm delivery [odds ratio 9.5 (95% CI 2.9-31.1)]; 4) subclinical intra-amniotic inflammation, defined as an elevation of IL-6 (≥2.9 ng/mL) or IP-10 (≥2.2 ng/mL) concentration above the 95th percentile of patients who had uncomplicated term delivery (n=652 for IL-6 and n=633 for IP-10), was observed in 6.3% (50/796) and 5.8% (45/770) of cases, respectively. Although each type of inflammation is a risk factor for spontaneous preterm delivery, many patients had a term delivery without complication; 5) the amniotic fluid in the midtrimester did not contain microorganisms detectable with cultivation techniques.

CONCLUSIONS

INTRA-amniotic inflammation is heterogeneous. Some patients have elevated amniotic fluid concentrations of IL-6, and are at risk for spontaneous preterm delivery before 32 weeks of gestation, while others have an elevated IP-10 (a chemotactic T-cell chemokine) and such patients are at risk for spontaneous preterm delivery after 32 weeks of gestation. A fraction of patients have subclinical intra-amniotic inflammation and deliver at term. The clinical significance of this condition remains to be determined.

Amniotic fluid inflammatory score is associated with pregnancy outcome in patients with mid trimester short cervix

OBJECTIVE

We propose a novel amniotic fluid inflammatory score from a comprehensive cytokine analysis of patients with mid-trimester short cervix.

STUDY DESIGN

Amniotic fluid from singleton gestations (n = 44) with a cervical length of ≤25 mm between 16-24 weeks was assayed for 25 inflammatory mediators. Patient data were stratified according to gestational age at delivery (<34 vs ≥34 weeks). Mediators that reached statistical significance were included in the amniotic fluid inflammatory score. Patients were assigned 1 point for each significant mediator if their level was in the upper quartile. The amniotic fluid inflammatory score was determined, and its relationship to other clinical characteristics was examined.

RESULTS

Fourteen mediators met the criteria. A score of ≥8 was predictive of delivery at <34 weeks' gestation (sensitivity, 87.0%; specificity, 100%; positive predictive value, 100%; negative predictive value, 87.5%). Twenty patients had a high inflammatory score (≥8); 24 patients had a low score. All patients with a high inflammatory score delivered at <30 weeks' gestation.

CONCLUSION

The amniotic fluid inflammatory score is related to delivery outcome and clinical characteristics.

Evolutionary-developmental perspectives on immune system interactions among the pregnant woman, placenta, and fetus, and responses to sexually transmitted infectious agents

A balance has evolved over deep time between the various immune systems of the "triad" that is linked together for a short period: the pregnant woman, the fetus, and the placenta. This balance is affected by, and helps to determine, the immune responses to maternal infectious agents that may be transmitted to the fetus/infant transplacentally, intrapartum, or via breast milk. This review identifies newer evolutionary concepts and processes related particularly to the human placenta, innate and adaptive immune systems involved in tolerance, and in responses to sexually transmitted infectious (STI) agents that may be pathogenic to the fetus/infant at different gestational periods and in the first year of life. An evolutionary-developmental (EVO-DEVO) perspective has been applied to the complexities within, and among, the different actors and their beneficial or deleterious outcomes. Such a phylogenetic and ontogenic approach has helped to stimulate several basic questions and suggested possible explanations and novel practical interventions.

Nutritional modulation of the gut microbiota and immune system in preterm neonates susceptible to necrotizing enterocolitis

The gastrointestinal inflammatory disorder, necrotizing enterocolitis (NEC), is among the most serious diseases for preterm neonates. Nutritional, microbiological and immunological dysfunctions all play a role in disease progression but the relationship among these determinants is not understood. The preterm gut is very sensitive to enteral feeding which may either promote gut adaptation and health, or induce gut dysfunction, bacterial overgrowth and inflammation. Uncontrolled inflammatory reactions may be initiated by maldigestion and impaired mucosal protection, leading to bacterial overgrowth and excessive nutrient fermentation. Tumor necrosis factor alpha, toll-like receptors and heat-shock proteins are identified among the immunological components of the early mucosal dysfunction. It remains difficult, however, to distinguish the early initiators of NEC from the later consequences of the disease pathology. To elucidate the mechanisms and identify clinical interventions, animal models showing spontaneous NEC development after preterm birth coupled with different forms of feeding may help. In this review, we summarize the literature and some recent results from studies on preterm pigs on the nutritional, microbial and immunological interactions during the early feeding-induced mucosal dysfunction and later NEC development. We show that introduction of suboptimal enteral formula diets, coupled with parenteral nutrition, predispose to disease, while advancing amounts of mother's milk from birth (particularly colostrum) protects against disease. Hence, the transition from parenteral to enteral nutrition shortly after birth plays a pivotal role to secure gut growth, digestive maturation and an appropriate response to bacterial colonization in the sensitive gut of preterm neonates.

Interrelationship of cytokines, hypothalamic-pituitary-adrenal axis hormones, and psychosocial variables in the prediction of preterm birth

BACKGROUND/AIMS

To examine the relationship of biological mediators (cytokines, stress hormones), psychosocial, obstetric history, and demographic factors in the early prediction of preterm birth (PTB) using a comprehensive logistic regression model incorporating diverse risk factors.

METHODS

In this prospective case-control study, maternal serum biomarkers were quantified at 9-23 weeks' gestation in 60 women delivering at <37 weeks compared to 123 women delivering at term. Biomarker data were combined with maternal sociodemographic factors and stress data into regression models encompassing 22 preterm risk factors and 1st-order interactions.

RESULTS

Among individual biomarkers, we found that macrophage migration inhibitory factor (MIF), interleukin-10, C-reactive protein (CRP), and tumor necrosis factor-alpha were statistically significant predictors of PTB at all cutoff levels tested (75th, 85th, and 90th percentiles). We fit multifactor models for PTB prediction at each biomarker cutoff. Our best models revealed that MIF, CRP, risk-taking behavior, and low educational attainment were consistent predictors of PTB at all biomarker cutoffs. The 75th percentile cutoff yielded the best predicting model with an area under the ROC curve of 0.808 (95% CI 0.743-0.874).

CONCLUSION

Our comprehensive models highlight the prominence of behavioral risk factors for PTB and point to MIF as a possible psychobiological mediator.

The role of human beta defensins 2 and 3 in the second trimester amniotic fluid in predicting preterm labor and premature rupture of membranes

AIM

Human beta defensins 2 (HBD2) and 3 (HBD3) are peptides expressed in the amnion and chorion. This is a matched case control study conducted in our Department to determine whether second trimester amniotic fluid HBD2 and HBD3 concentrations measured at the time of genetic amniocentesis could be potential markers of preterm labor prediction.

METHODS

Amniotic fluid HBD2 and HBD3 were determined by an enzyme-linked immunosorbent assay (ELISA) Women with preterm labor were defined as cases (N=41) while for each case a woman matched for age delivering at term served as control (N=41). Subgroup analysis was conducted to examine possible associations of HBD2 and HBD3 in cases of premature rupture of membranes. Nineteen women with preterm labor and premature rupture of membranes were defined as cases while for every case a woman matched for maternal age delivering at term served as control (N1=19). Results were presented as odds ratios (OR) and 95% confidence intervals. Statistical analysis used STATA 8.2 and SPSS 11.5 edition. A P-value of <0.05 was considered statistically significant.

RESULTS

Amniotic fluid concentrations of HBD2 at the time of genetic amniocentesis were positively associated with preterm premature rupture of membranes (P=0.028), but not with preterm labour. No association of HBD3 and preterm birth was documented.

CONCLUSION

Second trimester amniotic fluid HBD2 might be a predictor of premature rupture of membranes.

The anti-inflammatory limb of the immune response in preterm labor, intra-amniotic infection/inflammation, and spontaneous parturition at term: a role for interleukin-10

OBJECTIVE

The anti-inflammatory limb of the immune response is crucial for dampening inflammation. Spontaneous parturition at term and preterm labor (PTL) are mediated by inflammation in the cervix, membranes, and myometrium. This study focuses on the changes in the amniotic fluid concentrations of the anti-inflammatory cytokine interleukin (IL)- 10. The objectives of this study were to determine whether there is a relationship between amniotic fluid concentrations of IL-10 and gestational age, parturition (at term and preterm), and intra-amniotic infection/inflammation (IAI).

STUDY DESIGN

A cross-sectional study was conducted including 301 pregnant women in the following groups: (1) mid-trimester of pregnancy who delivered at term (n = 112); (2) mid-trimester who delivered preterm neonates (n = 30); (3) term not in labor without IAI (n = 40); (4) term in labor without IAI (n = 24); (5) term in labor with IAI (n = 20); (6) PTL without IAI who delivered at term (n = 31); (7) PTL without IAI who delivered preterm (n = 30); (8) PTL with IAI who delivered preterm (n = 14). IL-10 concentrations in amniotic fluid were determined by a specific and sensitive immunoassay. Non-parametric statistics were used for analysis.

RESULTS

(1) IL-10 was detectable in amniotic fluid and its median concentration did not change with gestational age from mid-trimester to term. (2) Patients in labor at term had a significantly higher median amniotic fluid IL-10 concentration than that of patients at term not in labor (p = 0.04). (3) Women at term in labor with IAI had a significantly higher median amniotic fluid IL-10 concentration than that of patients at term in labor without IAI (p = 0.02). (4) Women with PTL and IAI who delivered preterm had a significantly higher median amniotic fluid concentration of IL-10 than those without IAI who delivered preterm and than those who delivered at term (p = 0.009 and p < 0.001, respectively). (5) Among patients with preterm labor without IAI, those who delivered preterm had a significantly higher median amniotic fluid IL-10 concentration than those who delivered at term (p = 0.03).

CONCLUSIONS

The anti-inflammatory cytokine IL-10 is detectable in the amniotic fluid of normal pregnant women. Spontaneous parturition at term and in preterm gestation is associated with increased amniotic fluid concentrations of IL-10. IAI (preterm and at term) is also associated with increased amniotic fluid concentrations of IL-10. We propose that IL-10 has a role in the regulation of the immune response in vivo by initiating actions that dampen inflammation.

Amniotic fluid cytokine profile in association with fetal hyperechogenic bowel

OBJECTIVES

Fetal hyperechogenic bowel (FEB) is associated with infection, chromosomal abnormalities and poor fetal outcome. FEB may result from an intrauterine fetal bowel cytokine-mediated inflammatory response. Since alterations in the levels of the cytokines interleukin (IL)-6, IL-8, IL-10, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma are associated with pregnancy complications and necrotizing enterocolitis, this study aimed: (i) to determine their involvement in the pathophysiology of FEB and (ii) to identify their role as amniotic fluid markers of this condition.

STUDY DESIGN

In this prospective case-control study, amniotic fluid was collected by transabdominal amniocentesis from pregnant women with fetuses presenting (n=10)--or not (n=30)--with FEB during routine 18-20 week ultrasound scans. Cell-free amniotic fluid samples were analysed for cytokine concentrations by fluid-phase multiplex immunoassay. Data were compared by Mann-Whitney U-tests and Pearson correlations.

RESULTS

Amniotic fluid IL-8 levels were significantly higher in the FEB group. There was a positive correlation between IL-6 and each of IL-8 and INF-gamma, as well as between IL-8 and IL-10, and TNF-alpha and INF-gamma.

CONCLUSIONS

FEB likely ensues from a fetal inflammatory process involving IL-8 and, possibly, IL-6 and IL-10. This indicates the potential of immunomodulatory therapy in the management of FEB.