First trimester low maternal serum pregnancy associated plasma protein-A (PAPP-A) as a screening method for adverse pregnancy outcomes

Pregnancy-associated plasma protein A (PAPP-A) as a first trimester serum biomarker for preeclampsia screening: a systematic review and meta-analysis

OBJECTIVE

The aim of this study is to systematically examine the role of the pregnancy-associated plasma protein A (PAPP-A) serum biomarker in the first trimester screening of preeclampsia (PE).

MATERIALS AND METHODS

A systematic search of the literature was conducted on PubMed via Medline, and Cochrane Library up to 8 November 2022, for prospective studies evaluating PAPP-A serum levels in first trimester pregnant women as a screening biomarker for PE. Eligible were all prospectively designed case-control or cohort studies, published in English. Two investigators independently examined the studies and the studies' characteristics were extracted. Newcastle-Ottawa Scale (NOS) for case-control and cohort studies were applied to assess the risk of bias. For the quantitative analysis of the studies, a meta-analysis was also performed.

RESULTS

A total of 22 studies including 33,651 pregnant women were assessed, of whom, 2001 were diagnosed with PE. A meta-analysis was performed, showing that PAPP-A levels in the first trimester were significantly lower in early onset preeclamptic women (MD: -0.24, 95% CI: -0.37, -0.11, p = .0002), late onset (MD: -0.15, 95% CI: -0.25, -0.05, p = .03), and total preeclamptic cases (MD = -0.17, 95% CI = -0.23, -0.11, p < .00001) when compared with controls.

CONCLUSIONS

Our results suggest that PAPP-A can be a promising predictor in early screening for PE; hence, women at risk can be diagnosed early in their pregnancy stage and benefit from individualized PE treatment before it progresses.

Prediction of late-onset preeclampsia using plasma proteomics: a longitudinal multi-cohort study

Preeclampsia is a pregnancy disorder with substantial perinatal and maternal morbidity and mortality. Pregnant women at risk of preeclampsia would benefit from early detection for follow-up, timely interventions and delivery. Several attempts have been made to identify protein biomarkers of preeclampsia, but findings vary with demographics, clinical characteristics, and time of sampling. In the current study, we combined three independent longitudinal pregnancy cohorts (Detroit, Stanford and Oslo) resulting in 124 late-onset preeclampsia (LOPE) cases and 178 gestational age matched controls, and analyzed > 1000 proteins in maternal plasma sampled between 12 and 34 weeks of gestation. Differential abundance analysis of combined protein data revealed increased deviation in protein abundance trajectories throughout gestation in women destined to develop LOPE compared to controls. There were no differentially abundant proteins at time interval T1 (12-19 weeks), yet 31 differentially abundant proteins were found at time interval T2 (19-27 weeks), and 48 proteins at time interval T3 (27- 34 weeks). Multi-protein random forest models assessed via cross-validation predicted LOPE with an area under the ROC curve of 0.72 (0.65-0.78), 0.76 (0.71-0.81) and 0.80 (0.75-0.85) at time interval T1, T2 and T3, respectively. The results at T3 were confirmed using a leave-one-cohort-out analysis suggesting cross-cohort consistency, and at T1 and T2 when the largest two cohorts were used as training sets.

First trimester maternal serum PAPP-A and free β-hCG levels and risk of SGA or LGA in women with and without GDM

BACKGROUND

Maternal gestational diabetes (GDM), small (SGA) and large (LGA) for gestational age neonates are associated with increased morbidity in both mother and child. We studied how different levels of first trimester pregnancy associated plasma protein-A (PAPP-A) and free beta human chorionic gonadotropin (fβ-hCG) were associated with SGA and LGA in GDM pregnancies and controls.

METHODS

Altogether 23 482 women with singleton pregnancies participated in first trimester combined screening and delivered between 2014 and 2018 in Northern Finland and were included in this retrospective case-control study. Women with GDM (n = 4697) and controls without GDM (n = 18 492) were divided into groups below 5th and 10th or above 90th and 95th percentile (pc) PAPP-A and fβ-hCG MoM levels. SGA was defined as a birthweight more than two standard deviations (SD) below and LGA more than two SDs above the sex-specific and gestational age-specific reference mean. Odds ratios were adjusted (aOR) for maternal age, BMI, ethnicity, IVF/ICSI, parity and smoking.

RESULTS

In pregnancies with GDM the proportion of SGA was 2.6% and LGA 4.5%, compared to 3.3% (p = 0.011) and 1.8% (p < 0.001) in the control group, respectively. In ≤ 5th and ≤ 10th pc PAPP-A groups, aORs for SGA were 2.7 (95% CI 1.5-4.7) and 2.2 (95% CI 1.4-3.5) in the GDM group and 3.8 (95% CI 3.0-4.9) and 2.8 (95% CI 2.3-3.5) in the reference group, respectively. When considering LGA, there was no difference in aORs in any high PAPP-A groups. In the low ≤ 5 percentile fβ-hCG MoM group, aORs for SGA was 2.3 (95% CI 1.8-3.1) in the control group. In fβ-hCG groups with GDM there was no association with SGA and the only significant difference was ≥ 90 percentile group, aOR 1.6 (95% CI 1.1-2.5) for LGA.

CONCLUSION

Association with low PAPP-A and SGA seems to be present despite GDM status. High PAPP-A levels are not associated with increased LGA risk in women with or without GDM. Low fβ-hCG levels are associated with SGA only in non-GDM pregnancies.

Human uterine natural killer cells regulate differentiation of extravillous trophoblast early in pregnancy

In humans, balanced invasion of trophoblast cells into the uterine mucosa, the decidua, is critical for successful pregnancy. Evidence suggests that this process is regulated by uterine natural killer (uNK) cells, but how they influence reproductive outcomes is unclear. Here, we used our trophoblast organoids and primary tissue samples to determine how uNK cells affect placentation. By locating potential interaction axes between trophoblast and uNK cells using single-cell transcriptomics and in vitro modeling of these interactions in organoids, we identify a uNK cell-derived cytokine signal that promotes trophoblast differentiation at the late stage of the invasive pathway. Moreover, it affects transcriptional programs involved in regulating blood flow, nutrients, and inflammatory and adaptive immune responses, as well as gene signatures associated with disorders of pregnancy such as pre-eclampsia. Our findings suggest mechanisms on how optimal immunological interactions between uNK cells and trophoblast enhance reproductive success.