An evaluation of calprotectin as serum marker of preeclampsia: a systematic review of observational studies

Predictive potential of various plasma inflammation-, angiogenesis-, and extracellular matrix remodeling-associated mediators for intra-amniotic inflammation and/or microbial invasion of the amniotic cavity in preterm labor

PURPOSE

To determine whether various inflammatory-, angiogenic/anti-angiogenic-, and extracellular matrix remodeling-associated proteins in plasma, alone or in combination with conventional blood-based markers, can predict intra-amniotic inflammation and/or microbial invasion of the amniotic cavity (IAI/MIAC) in women with spontaneous preterm labor (PTL).

METHODS

A total of 193 singleton pregnant women with PTL (23-33 weeks) were included in this retrospective cohort study. Plasma samples were obtained at the time of amniocentesis. Amniotic fluid (AF) was cultured for microorganism detection and consequent MIAC diagnosis. IL-6 levels were determined in AF and used to identify IAI (AF IL-6 ≥ 2.6 ng/mL). Endostatin, haptoglobin, IGFBP-2/3, LBP, M-CSF, MMP-2/8, pentraxin 3, PlGF, S100A8/A9, and VEGFR-1 levels were assayed in plasma samples by ELISA. CRP levels and neutrophil-to-lymphocyte ratio (NLR) were measured.

RESULTS

Plasma LBP, MMP-8, and S100A8/A9 levels, CRP levels, and NLR were significantly higher, and plasma IGFBP-2 and MMP-2 levels were significantly lower in women with IAI/MIAC than in those without this condition, whereas no baseline variables differed significantly between the two groups. Using a stepwise regression analysis, a noninvasive prediction model for IAI/MIAC was developed, which included plasma LBP, MMP-2, and MMP-8 levels (area under the curve [AUC], 0.785). The AUC for this prediction model was significantly or borderline greater than that of any single factor included in the model.

CONCLUSIONS

IGFBP-2, LBP, MMP-2, MMP-8, and S100A8/A9 may represent valuable plasma biomarkers for predicting IAI/MIAC in women with PTL. Combination of LBP, MMP-2, and MMP-8 expression data can significantly improve the predictive potential for IAI/MIAC.

Biomarkers of Pre-eclampsia in Pregnant Women With Gestational Diabetes and Pre-existing Type 2 Diabetes: A Systematic Review

Pre-eclampsia (PE) is one of the leading causes of maternal and perinatal health morbidity, producing more than 4.6% of complications in pregnancy worldwide. This systematic review was conducted to determine the significance of specific biomarkers in predicting PE in gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (DM). The review measured and explained the significant abnormalities in lipids, blood glucose, cytokines, inflammatory markers, placental proteins, urinary proteins, and other serum biomarkers that contribute to the development of PE in GDM and type 2 DM populations. We searched CINAHL, EMBASE, Medline, Maternity and Infant care, Scopus, and Web of Science. Studies were included if they had a measurable component in the blood serum or urine of women who developed PE and suffered from GDM or pre-existing type 2 DM. A narrative synthesis was conducted instead of a meta-analysis due to the high heterogeneity of data from the studies. A total of 2,593 studies were screened, producing eight relevant studies. Twenty-seven different biomarkers were investigated from the study group of 40 to 1,344 participants. No single biomarker was identified; however, there is a need for further research on specific biomarkers of PE, especially in CRP, FABP4, and microalbuminuria in the GDM-PE group and calprotectin in the type 2 DM population. Many biomarkers were identified as practical in predicting PE when combined with other biomarkers and more data are required to verify the predictability of the diagnostic markers in pregnant women.

Gut Micro- and Mycobiota in Preeclampsia: Bacterial Composition Differences Suggest Role in Pathophysiology

Preeclampsia is a severe pregnancy-related inflammatory disease without an effective treatment. The pathophysiology remains partly unknown. However, an increased inflammatory response and oxidative stress are part of the maternal systemic reaction. Recent data have suggested that dysbiosis of the gut microbiome plays a role in preeclampsia as well as other inflammatory diseases. However, dysbiosis in preeclampsia has not been studied in a Scandinavian population. Furthermore, although the fungal flora may also have anti-inflammatory properties, it has never been studied in preeclampsia. We included 25 preeclamptic and 29 healthy third-trimester women for the ITS and 16S sequencing of fungal and bacterial microbiota, respectively. Calprotectin was measured to assess systemic and intestinal inflammatory responses. The fungal diversity differed with BMI and gestational length, suggesting a link between fungi and the immune changes seen in pregnancy. An LEfSe analysis showed 18 significantly differentially abundant bacterial taxa in PE, including enriched Bacteroidetes and depleted Verrucomicrobia and Syntergistota at the phylum level and depleted Akkermansia at the genus level, suggesting a role in the pathophysiology of PE.

Study of sRAGE, HMGB1, AGE, and S100A8/A9 Concentrations in Plasma and in Serum-Extracted Extracellular Vesicles of Pregnant Women With Preterm Premature Rupture of Membranes

Preterm premature rupture of membranes (PPROM), defined as rupture of fetal membranes prior to 37 weeks of gestation, complicates approximately 2–4% of pregnancies and is responsible for 40% of all spontaneous preterm births. PPROM arises from complex pathophysiological pathways with a key actor: inflammation. Sterile inflammation is a feature of senescence-associated fetal membrane maturity. During specific steps of sterile inflammation, cells also release highly inflammatory damage-associated molecular pattern markers (DAMPs), such as high-mobility group box 1 (HMGB1) or S100A8/A9, known to link and activate the receptor for advanced glycation end products (RAGE). The objective of this study was to measure longitudinally during pregnancy concentrations of the soluble form of RAGE (sRAGE) and its main ligands (AGE, HMGB1, S100A8/A9) in blood specimens. We studied 246 pregnant women (82 with PPROM and 164 matched control pregnant women without complications) from a cohort of 7,866 pregnant women recruited in the first trimester and followed during pregnancy until delivery. sRAGE, AGE, HMGB1, and S100A8/A9 concentrations were measured in plasma and in serum-extracted extracellular vesicles from first trimester (T1), second trimester (T2), and delivery (D). In plasma, we observed, in both PPROM and control groups, (i) a significant increase of HMGB1 concentrations between T1 vs. T2, T1 vs. D, but not between T2 vs. D; (ii) a significant decrease of sRAGE concentrations between T1 and T2 and a significant increase between T2 and D; (iii) a significant decrease of AGE from T1 to D; (iv) no significant variation of S100A8/A9 between trimesters. In intergroup comparisons (PPROM vs. control group), there were no significant differences in time variation taking into account the matching effects. There was a correlation between plasma and serum-extracted extracellular vesicle concentrations of sRAGE, AGE, HMGB1, and S100A8/A9. Our results suggest that the rupture of fetal membranes (physiological or premature) is accompanied by a variation in plasma concentrations of sRAGE, HMGB1, and AGE. The study of RAGE and its main ligands in extracellular vesicles did not give additional insight into the pathophysiological process conducting to PPROM.

Increased placental macrophages and a pro-inflammatory profile in placentas and maternal serum in infants with a decreased growth rate in the third trimester of pregnancy

PROBLEM

There is growing evidence for the role of placental inflammation in the pathophysiology of pregnancy complications including fetal growth restriction (FGR). This study aimed to characterize the inflammatory profile in the maternal circulation and the placenta of infants who were growth restricted and those that were small for gestational age (SGA).

METHOD OF STUDY

Placental villous tissue and maternal serum were obtained from pregnancies where infants were SGA at birth or who had a decreasing growth rate (≥25 centiles) across the third trimester. Immunohistochemical and histological analyses of placental samples were conducted for macrophage number, alongside vascular and cell turnover analysis. Inflammatory profile was analyzed in maternal and placental compartments via ELISAs and multiplex assays.

RESULTS

There were significantly more CD163⁺ macrophages in placentas of infants with a decreased growth rate compared to controls, but not in SGA infants (median 8.6/ nuclei vs 3.8 and 2.9, P = .008 and P = .003, respectively). Uric acid (P = .0007) and IL-8 (P = .0008) were increased in placentas, and S100A8 (P < .0002) was increased in maternal serum of infants with decreased growth rate. No changes in the maternal serum or placental lysates of SGA infants were observed.

CONCLUSION

The evidence of an altered inflammatory profile in infants with a decreasing growth rate, but not in those that were born SGA, provides further evidence that inflammation plays a role in true FGR. It remains unclear whether the increased placental macrophages occur as a direct result, or as a consequence of the pro-inflammatory environment observed in fetal growth restriction.

Calprotectin in pregnancy and pregnancy-associated diseases: a systematic review and prospective cohort study

PURPOSE

Calprotectin, a marker of acute and chronic inflammation, may play a role in pregnancy-associated disorders. We aimed to summarize available clinical data on calprotectin in pregnancy and to establish normal values of calprotectin during the course of pregnancy.

METHODS

We performed a systematic review of the databases PubMed and Cochrane Central Register of Controlled Trials to identify experimental and clinical evidence assessing the role of calprotectin in pregnancy. In addition, we performed a prospective cohort study assessing serum and urine calprotectin throughout pregnancy.

RESULTS

We identified 17 studies investigating 1638 pregnant women, 151 newborns, and 99 non-pregnant controls, measuring calprotectin in different compartments. Calprotectin was present in meconium and elevated in fecal samples of pregnant women with active inflammatory bowel disease. In women with pregnancy-induced hypertension, mild and severe preeclampsia (PE), calprotectin was significantly elevated in maternal plasma and serum, but not in fetal serum, amniotic fluid, and umbilical cord blood. For the cohort study, we recruited 196 pregnant women. PE and concomitant renal disease were present in 6/196 (3%) and 11/196 (5.6%) of women, respectively. Throughout pregnancy, median serum and urine levels of calprotectin largely exceed reported concentrations of the healthy non-pregnant population, but showed no significant variations between trimesters 1-3 and post-partum. Calprotectin in serum was correlated with systolic blood pressure and in urine with leukocytes and total protein. No significant differences were found in subgroup analyses of smokers vs. non-smokers, PE vs. none, and renal disease (kidney stones, reflux) vs. none.

CONCLUSION

Calprotectin concentrations in amnion fluid and stools serve as potential indicators of inflammatory states during pregnancy. Urinary calprotectin concentrations are continuously high during pregnancy and show no significant variations between trimesters 1-3 and post-partum.

Immune biomarkers in maternal plasma to identify histologic chorioamnionitis in women with preterm labor

PURPOSE

To determine whether various selected immune-related proteins in maternal plasma, alone or in combination, can predict histologic chorioamnionitis (HCA) in women with preterm labor, and to compare the predictive abilities of these biomarkers with that of serum C-reactive protein (CRP).

METHODS

This retrospective cohort study included 74 consecutive women with preterm labor (23-34 gestational weeks) who delivered within 96 h of blood sampling. Their serum CRP levels were also measured. The stored maternal plasma was assayed for interleukin (IL)-6, matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinases (TIMP)-1, angiopoietin-2, S100 A8/A9, CXCL14, APRIL, and insulin-like growth factor-binding protein-2 (IGFBP-2), using ELISA kits. The primary outcome measure was HCA.

RESULTS

HCA was detected in 59.4% (44/74) of women. Women with HCA had a significantly lower median gestational age at sampling and plasma IGFBP-2 level, and higher median plasma IL-6 and S100 A8/A9 levels than those without HCA. In multivariable analysis, high plasma IL-6 and low plasma IGFBP-2 levels were independently associated with the occurrence of HCA. However, the sensitivities, specificities, and areas under the curve of plasma IL-6, S100 A8/A9, and IGFBP-2, alone or in combination, were similar to or lower than those of serum CRP, for detecting HCA.

CONCLUSIONS

Our data suggest that plasma IL-6, S100 A8/A9, and IGFBP-2 could be potential novel biomarkers for predicting HCA in women with PTL; however, elevated plasma levels of these biomarkers, alone or in combination, do not predict HCA better than serum CRP.

Alarmins at the maternal-fetal interface: involvement of inflammation in placental dysfunction and pregnancy complications 1

Inflammation is known to be associated with placental dysfunction and pregnancy complications. Infections are well known to be a cause of inflammation but they are frequently undetectable in pregnancy complications. More recently, the focus has been extended to inflammation of noninfectious origin, namely caused by endogenous mediators known as "damage-associated molecular patterns (DAMPs)" or alarmins. In this manuscript, we review the mechanism by which inflammation, sterile or infectious, can alter the placenta and its function. We discuss some classical DAMPs, such as uric acid, high mobility group box 1 (HMGB1), cell-free fetal deoxyribonucleic acid (DNA) (cffDNA), S100 proteins, heat shock protein 70 (HSP70), and adenosine triphosphate (ATP) and their impact on the placenta. We focus on the main placental cells (i.e., trophoblast and Hofbauer cells) and describe the placental response to, and release of, DAMPs. We also covered the current state of knowledge about the role of DAMPs in pregnancy complications including preeclampsia, fetal growth restriction, preterm birth, and stillbirth and possible therapeutic strategies to preserve placental function.

Genetic and non-genetic risk factors for pre-eclampsia: umbrella review of systematic reviews and meta-analyses of observational studies

OBJECTIVE

To summarize evidence from the literature on genetic and non-genetic risk factors associated with pre-eclampsia (PE), assess the presence of statistical bias in the studies and identify risk factors for which there is robust evidence supporting their association with PE.

METHODS

PubMed and ISI Web of Science were searched from inception to October 2016, to identify systematic reviews and meta-analyses of observational studies examining associations between genetic or non-genetic risk factors and PE. For each meta-analysis, the summary-effect size was estimated using random-effects and fixed-effects models, along with 95% CIs and the 95% prediction interval. Between-study heterogeneity was expressed using the I2 statistic, and evidence of small-study effects (large studies had significantly more conservative results than smaller studies) and evidence of excess significance bias (too many studies with statistically significant results) were estimated.

RESULTS

Fifty-eight eligible meta-analyses were identified, which included 1466 primary studies and provided data on 130 comparisons of risk factors associated with PE, covering a wide range of comorbid diseases, genetic factors, exposure to environmental agents and biomarkers. Sixty-five (50%) associations had nominally statistically significant findings at P < 0.05, while 16 (12%) were significant at P < 10-6 . Sixty-five (50%) associations had large or very large heterogeneity. Evidence for small-study effects and excess significance bias was found in 10 (8%) and 26 (20%) associations, respectively. The only non-genetic risk factor with convincing evidence for an association with PE was oocyte donation vs spontaneous conception, which had a summary odds ratio of 4.33 (95% CI, 3.11-6.03), was supported by 2712 cases with small heterogeneity (I2  = 26%) and 95% prediction intervals excluding the null value, and without hints of small-study effects (P for Egger's test > 0.10) or excess of significance (P > 0.05). Of the statistically significant (P < 0.05) genetic risk factors for PE, only PAI-1 4G/5G (recessive model) polymorphism was supported by strong evidence for a contribution to the pathogenesis of PE. Eleven factors (serum iron level, pregnancy-associated plasma protein-A, chronic kidney disease, polycystic ovary syndrome, mental stress, bacterial and viral infections, cigarette smoking, oocyte donation vs assisted reproductive technology, obesity vs normal weight, severe obesity vs normal weight and primiparity) presented highly suggestive evidence for an association with PE.

CONCLUSIONS

A large proportion of meta-analyses of genetic and non-genetic risk factors for PE have caveats that threaten their validity. Oocyte donation vs spontaneous conception and PAI-1 4G/5G polymorphism (recessive model) showed the strongest consistent evidence for an association with risk for PE. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.