Validation of machine-learning model for first-trimester prediction of pre-eclampsia using cohort from PREVAL study.

OBJECTIVE: Effective first-trimester screening for pre-eclampsia (PE) can be achieved using a competing-risks model that combines risk factors from the maternal history with multiples of the median (MoM) values of biomarkers. A new model using artificial intelligence through machine-learning methods has been shown to achieve similar screening performance without the need for conversion of raw data of biomarkers into MoM. This study aimed to investigate whether this model can be used across populations without specific adaptations. METHODS: Previously, a machine-learning model derived with the use of a fully connected neural network for first-trimester prediction of early (< 34 weeks), preterm (< 37 weeks) and all PE was developed and tested in a cohort of pregnant women in the UK. The model was based on maternal risk factors and mean arterial blood pressure (MAP), uterine artery pulsatility index (UtA-PI), placental growth factor (PlGF) and pregnancy-associated plasma protein-A (PAPP-A). In this study, the model was applied to a dataset of 10 110 singleton pregnancies examined in Spain who participated in the first-trimester PE validation (PREVAL) study, in which first-trimester screening for PE was carried out using the Fetal Medicine Foundation (FMF) competing-risks model. The performance of screening was assessed by examining the area under the receiver-operating-characteristics curve (AUC) and detection rate (DR) at a 10% screen-positive rate (SPR). These indices were compared with those derived from the application of the FMF competing-risks model. The performance of screening was poor if no adjustment was made for the analyzer used to measure PlGF, which was different in the UK and Spain. Therefore, adjustment for the analyzer used was performed using simple linear regression. RESULTS: The DRs at 10% SPR for early, preterm and all PE with the machine-learning model were 84.4% (95% CI, 67.2-94.7%), 77.8% (95% CI, 66.4-86.7%) and 55.7% (95% CI, 49.0-62.2%), respectively, with the corresponding AUCs of 0.920 (95% CI, 0.864-0.975), 0.913 (95% CI, 0.882-0.944) and 0.846 (95% CI, 0.820-0.872). This performance was achieved with the use of three of the biomarkers (MAP, UtA-PI and PlGF); inclusion of PAPP-A did not provide significant improvement in DR. The machine-learning model had similar performance to that achieved by the FMF competing-risks model (DR at 10% SPR, 82.7% (95% CI, 69.6-95.8%) for early PE, 72.7% (95% CI, 62.9-82.6%) for preterm PE and 55.1% (95% CI, 48.8-61.4%) for all PE) without requiring specific adaptations to the population. CONCLUSIONS: A machine-learning model for first-trimester prediction of PE based on a neural network provides effective screening for PE that can be applied in different populations. However, before doing so, it is essential to make adjustments for the analyzer used for biochemical testing. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Change in prevalence of preterm birth in Israel following publication of national guidelines recommending routine sonographic cervical-length measurement at 19-25 weeks' gestation.

OBJECTIVE: To compare the prevalence of preterm birth (PTB) (delivery before 37 weeks) in Israel before and after publication of national guidelines recommending second-trimester sonographic cervical-length (CL) measurement. METHODS: The Israeli Society of Obstetrics and Gynecology (ISOG) guidelines, issued on 1 January 2012, specified that CL should be measured transabdominally or, if this is not possible, transvaginally, at the 19-25-week ultrasound anomaly scan and that CL < 25 mm should indicate further work-up and treatment, although the type of treatment was unspecified. In 2000, the Israel Ministry of Health issued a legal requirement for the submission of delivery records to a national registry. These data were used to compare PTB prevalence in the period before (2000-2011) and that after (2012-2020) publication of the guidelines, as well as trends within each time period. Information was available on singleton and multiple pregnancy and maternal age and parity, as well as low birth weight (< 2500 g). RESULTS: During the period 2000-2020, there were 3 403 976 infants liveborn in Israel: 1 797 657 before and 1 606 319 after publication of the ISOG guidelines. There were 247 187 PTBs overall, with a prevalence of 7.64% (95% CI, 7.52-7.77%) before publication of the guidelines and 6.84% (95% CI, 6.43-7.24%) afterwards (P < 0.0002, two-tailed). The annual PTB prevalence was static in the first time period but declined by 0.18% per annum during the second period, after publication of the guidelines. The proportionate reduction in PTB prevalence after compared with before publication of the guidelines was 10% overall, 9% for PTB at 33-36 weeks, 18% for PTB at 28-32 weeks and 24% for PTB at < 28 weeks. After publication of the guidelines, reduced prevalence of PTB was observed among singletons (5.49% before vs 4.83% after, P < 0.0001), but not among infants in twin or higher-order multiple pregnancy. There was a statistically significant reduction in the rate of PTB following publication of the guidelines in both nulliparous and parous women and in the 19-39-year-old maternal-age group. Although reductions in PTB prevalence were also noted in high-risk age groups (maternal age < 19 years and ≥ 40 years), these did not reach statistical significance. Following publication of the guidelines, there was a statistically significant reduction in the prevalence of birth weight under 2500 g, of a magnitude similar to that for PTB prevalence. CONCLUSIONS: The publication of national guidelines recommending routine CL measurement at the time of the second-trimester anomaly scan was associated with a fall in PTB prevalence in singleton pregnancies. Whilst direct evidence linking screening with this fall in prevalence is lacking, it is likely that implementation of routine CL screening played an important role in the reduction of PTB rate. Our experience indicates that screening can be incorporated into the second-trimester anomaly scan. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Machine-learning-based prediction of pre-eclampsia using first-trimester maternal characteristics and biomarkers.

OBJECTIVE: To evaluate the accuracy of predicting the risk of developing pre-eclampsia (PE) according to first-trimester maternal demographic characteristics, medical history and biomarkers using artificial-intelligence and machine-learning methods. METHODS: The data were derived from prospective non-interventional screening for PE at 11-13 weeks' gestation at two maternity hospitals in the UK. The data were divided into three subsets. The first set, including 30 437 subjects, was used to develop the training process, the second set of 10 000 subjects was utilized to optimize the machine-learning hyperparameters and the third set of 20 352 subjects was coded and used for model validation. An artificial neural network was used to predict from the demographic characteristics and medical history the prior risk that was then combined with biomarker values to determine the risk of PE and preterm PE with delivery at < 37 weeks' gestation. An additional network was trained without including race as input. Biomarkers included uterine artery pulsatility index (UtA-PI), mean arterial blood pressure (MAP), placental growth factor (PlGF) and pregnancy-associated plasma protein-A. All markers were entered using raw values without conversion into standardized multiples of the median. The prediction accuracy was estimated using the area under the receiver-operating-characteristics curve (AUC). We further computed the detection rate at 10%, 20% and 40% false-positive rates (FPR). The impact of taking aspirin was also added. Shapley values were calculated to evaluate the contribution of each parameter to the prediction of risk. We used a non-parametric test to compare the expected AUC with the one obtained when we randomly scrambled the labels and kept the predictions. For the general prediction, we performed 10 000 permutations of the labels. When the AUC was higher than the one obtained in all 10 000 permutations, we reported a P-value of < 0.0001. For the race-specific analysis, we performed 1000 permutations. When the AUC was higher than the AUC in permutations, we reported a P-value of < 0.001. RESULTS: The detection rate for preterm PE vs no PE, at a 10% FPR, was 53.3% when screening by maternal factors only, and the corresponding AUC was 0.816; these increased to 75.3% and 0.909, respectively, with the addition of biomarkers into the model. Information on race was important for the prediction accuracy; when race was not used to train the model, at a 10% FPR, the detection rate of preterm PE vs no PE decreased to 34.5-45.5% (for different races) when screening by maternal factors only and to 55.0-62.1% when biomarkers were added. The major predictors of PE were high MAP and UtA-PI, and low PlGF. The accuracy of prediction of all PE cases was lower than that for preterm PE. Aspirin use was recommended for cases who were at high risk of preterm PE. The AUC of all PE vs no PE was 0.770 when screening by maternal factors and 0.817 when the biomarkers were added; the respective detection rates, at a 10% FPR, were 41.3% and 52.9%. CONCLUSIONS: Screening for PE using a non-linear machine-learning-based approach does not require a population-based normalization, and its performance is similar to that of logistic regression. Removing race information from the model reduces its prediction accuracy, especially for the non-white populations when only maternal factors are considered. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Placental protein 13 and decidual zones of necrosis: an immunologic diversion that may be linked to preeclampsia.

We evaluated the role of placental protein 13 (PP13; galectin 13) in the process of trophoblast invasion and decidual necrosis. Immunohistochemical analysis for PP13, immune cells, human placental lactogen, cytokeratin, and apoptosis markers was performed on 20 elective pregnancy termination specimens between 6 and 15 weeks of gestation. Placental protein 13 was localized to syncytiotrophoblasts in the chorionic villi and to occasional multinucleated luminal trophoblasts within converted decidual spiral arterioles. Cytotrophoblasts, anchoring trophoblasts, and invasive trophoblasts did not stain for PP13. Extracellular PP13 aggregates were found around decidual veins associated with T-cell-, neutrophil- and macrophage-containing decidual zones of necrosis (ZONEs). We hypothesize that PP13 is secreted into the intervillus space, drains through the decidua basalis veins, and forms perivenous PP13 aggregates which attract and activate maternal immune cells. Thus, syncytiotrophoblast-derived PP13 may create a ZONE that facilitates trophoblast invasion and conversion of the maternal spiral arterioles.

Placenta-bound and body fluid PP13 and its mRNA in normal pregnancy compared to preeclampsia, HELLP and preterm delivery.

OBJECTIVES: To compare the distribution of placental protein 13 (PP13) in fetal and maternal blood and amnionic fluid and to correlate it with PP13 protein and mRNA in the placenta. METHODS: Umbilical arterial serum, amnionic fluid, maternal venous serum and placental tissues were collected from normal outcome pregnancies (N = 63) (GA>37), early onset preeclampsia (PE) (N = 12, GA: 26-33), and HELLP syndrome (N = 5, GA: 27-29). Because PE and HELLP cases delivered preterm, cases of preterm delivery (PTD) (N = 6, GA: 31-36) served as additional control. PP13 was determined by ELISA, Western blot, and immunohistochemistry. PP13 mRNA was measured by PCR (RT-PCR). Continuous parameters were compared by t-test, P < 0.05 was considered significant. RESULTS: In women with normal pregnancy outcome significantly higher PP13 levels were found in maternal serum compared to amnionic fluid and negligible amount was found in fetal serum. A similar pattern was identified in cases of PTD with concentrations similar to term control. In PE and HELLP cases PP13 levels in amnionic fluid level were more than twice compared to maternal serum (P < 0.001). Umbilical cord level was negligible in PE but high in HELLP corresponding to the much higher level of PP13 in this patient group compared to all others. In the placenta PP13 level in term controls was higher compared to PTD. In PE and HELLP (similar early delivery time as PTD) the level was significantly higher (P < 0.01) compared to PTD or term controls. PP13 mRNA levels in term control and PTD were similar while PP13 mRNA levels in PE and HELLP placentas were significantly lower compared to term controls or PTD or the two combined. Syncytiotrophoblast labeling appeared stronger in PE and HELLP compared to term controls and PTD. CONCLUSIONS: In all cases but HELLP, PP13 in fetal blood is very low indicating that routing of PP13 to fetal blood is limited and that the fetus is unlikely to generate PP13. PP13 mRNA is lower in the third trimester at the time of disease while protein level accumulates and become higher creating an unparallel change in the level of the mRNA and the corresponding protein.

Placental and trophoblastic in vitro models to study preventive and therapeutic agents for preeclampsia.

In the field of preeclampsia, enormous efforts are ongoing to identify biomarkers predicting the syndrome already in the first trimester of pregnancy. At the same time, there is the need for in vitro models to test such biomarkers prior to their use in clinical trials. In addition, in vitro models may accelerate the development and evaluation of the benefit of any putative therapeutics. Therefore, in vitro systems have been established to evaluate the release of biomarkers and measure the effect of putative therapeutics using placental villous explants as well as the choriocarcinoma cell line BeWo. For explants, a cryogenic method to freeze, transport and thaw villous explants was developed to use such tissues for a multi-site tissue culture evaluation. Here we focus on three out of many in vitro models that have been established for human placental trophoblast. (1) Choriocarcinoma cell lines such as BeWo, Jeg-3 and Jar cells (2) isolated primary trophoblast cells, and (2) villous explants from normal placentas delivered at term. Cell lines were used to assess the effect of differentiation and fusion on the expression and release of a preeclampsia marker (placental protein 13; PP13) and beta-hCG. Moreover, cell lines were used to study the effect of putative preeclampsia therapeutics such as vitamins C and E, heparin and aspirin on marker release and viability. Cryopreservation of villous explants enabled shipment to a remote laboratory and testing of parameters in different countries using explants from one and the same placenta. Recently published data make it tempting to speculate that the choriocarcinoma cell line BeWo as well as fresh and cryogenically stored placental villous explants may well serve as in vitro models to study preventive and therapeutic agents in the field of preeclampsia.

Cryogenic and low temperature preservation of human placental villous explants - a new way to explore drugs in pregnancy disorders.

BACKGROUND: A major handicap in cell culture studies using human tissues is the insufficient availability of fresh material on site. A method was developed for cryogenic storage and low temperature preservation of human placental villous explants, facilitating multi-site distribution for functional studies. METHODS: Explants from term placentas were incubated with cryoprotectant agents (dimethyl-sulfoxide (DMSO), ethylene glycol, propanediol or Aedesta), frozen in liquid nitrogen, thawed and then cultured in-vitro. Viability was assessed by comparing frozen and thawed explants with non-frozen controls for morphological changes, lactate dehydrogenase (LDH) release, placenta protein 13 (PP13) secretion, and PCNA Western blotting. Functional studies determined the effect of oxygen and magnesium on explant viability. RESULTS: Cryoprotection by 3 M DMSO best maintained explants' viability, morphological integrity and PP13 release after freezing and thawing from liquid nitrogen. The effect of oxygen and magnesium was used to test the functional viability of cultured explants, after freezing in liquid nitrogen and transfer to dry ice for 1-5 days on site or for shipment to a remote lab. The tested parameters were similar between controls and cryogenically treated explants in the remote lab and the lab of origin, demonstrating the possibility of cryostoring explants for functional studies. CONCLUSION: Cryogenically stored placental villous explants shipped frozen can serve as a useful tool for comparative functional studies of placental villous tissues. The results of this pilot study also open the way for multi-site studies associated with drug tailoring for pregnancy disorders.

Pregenesys pre-eclampsia markers consensus meeting: What do we require from markers, risk assessment and model systems to tailor preventive strategies?

The Pregenesys Consensus Meeting held in Cambridge on 13 July 2009 was organized by the Pregenesys Consortium to review and critically discuss current knowledge regarding early markers of preeclampsia, to identify priorities and opportunities for future research, to consider issues that may need to be addressed in future recommendations and to highlight key issues in cost effectiveness and national policies concerning prediction and early screening for the risk of developing preeclampsia. This report summarizes the outcome of the Consensus Meeting and draws attention to issues for further investigation with specific regard to single versus multiple markers, early versus late risk identification, and the long-term effects on both maternal and perinatal health and the need to include these in any future cost-benefit assessment.

Effects of calcium, magnesium, low-dose aspirin and low-molecular-weight heparin on the release of PP13 from placental explants.

BACKGROUND: Preeclampsia is one of the leading causes for maternal and fetal morbidity. Attempts to prevent preeclampsia have already been made using low-dose aspirin, low-molecular-weight heparin (LMWH), and calcium supplementation. Magnesium sulphate is used at the time of disease to prevent eclampsia. Here we investigated the effect of these agents on PP13 release from placental explants. METHODS: Placentas harvested after C-section of term or preterm control and preeclampsia cases or first trimester terminations were used to obtain explants. Explants were incubated for 24h with/without respective agents, harvested, weighed and subjected to PP13 determination in the culture medium and the explant. LDH was used to determine viability. Dose response curves were obtained for each drug. P < 0.05 was considered significant. RESULTS: Exposure to magnesium (0.7-7g/day) slightly decreased PP13 release from controls, and slightly increased it in preeclampsia and first trimester termination. Calcium (0. 3-6g/day) showed a tendency to decrease the release in control and preeclampsia, whereas in first trimester release was increased in a bell-shaped manner. Aspirin (0-250 mg/day) tended to decrease the release in controls but increased it in a bell-shaped manner in first trimester and preeclampsia. LMWH showed no effect from 0 to 80 mg/day in controls but tended to decrease PP13 release in preeclampsia and first trimester. CONCLUSION: This data might point to a beneficial effect of aspirin and calcium supplementation in the first trimester of pregnancy and aspirin at the time of disease, although the interaction with the maternal system still needs to be elucidated.

Microarray profiling reveals that placental transcriptomes of early-onset HELLP syndrome and preeclampsia are similar.

BACKGROUND: The involvement of the placenta in the pathogenesis of preeclampsia and HELLP syndrome is well established, and placental lesions are also similar in these two syndromes. Here we aimed to examine the placental transcriptome and to identify candidate biomarkers in early-onset preeclampsia and HELLP syndrome. METHODS: Placental specimens were obtained at C-sections from women with early-onset preeclampsia and HELLP syndrome, and from controls who delivered preterm or at term. After histopathological examination, fresh-frozen placental specimens were used for microarray profiling and validation by qRT-PCR. Differential expression was analysed using log-linear models while adjusting for gestational age. Gene ontology and pathway analyses were used to interpret gene expression changes. Tissue microarrays were constructed from paraffin-embedded placental specimens and immunostained. RESULTS: Placental gene expression was gestational age-dependent among preterm and term controls. Out of the 350 differentially expressed genes in preeclampsia and 554 genes in HELLP syndrome, 224 genes (including LEP, CGB, LHB, INHA, SIGLEC6, PAPPA2, TREM1, and FLT1) changed in the same direction (elevated or reduced) in both syndromes. Many of these encode proteins that have been implicated as biomarkers for preeclampsia. Enrichment analyses revealed similar biological processes, cellular compartments and biological pathways enriched in early-onset preeclampsia and HELLP syndrome; however, some processes and pathways (e.g., cytokine-cytokine receptor interaction) were over-represented only in HELLP syndrome. CONCLUSION: High-throughput transcriptional and tissue microarray expression profiling revealed that placental transcriptomes of early-onset preeclampsia and HELLP syndrome largely overlap, underlying a potential common cause and pathophysiologic processes in these syndromes. However, gene expression changes may also suggest a more severe placental pathology and pronounced inflammatory response in HELLP syndrome than in preeclampsia.

Effects of vitamins C and E, acetylsalicylic acid and heparin on fusion, beta-hCG and PP13 expression in BeWo cells.

Preeclampsia is one of the leading causes for maternal and fetal morbidity. Placental protein 13 (PP13) is a placenta specific protein and with its decreased maternal serum levels in the first trimester it is one of the most promising markers to predict the syndrome in early pregnancy. In clinical trials attempts to prevent preeclampsia have already been made using low-dose aspirin, low-molecular-weight heparin, and antioxidants such as vitamins C and E. Here we investigated the effect of these agents on PP13 and beta-hCG levels using choriocarcinoma cell lines as surrogates for primary villous trophoblast. Five different cell lines were triggered with forskolin and cultured for 48 h. Amongst the five tested cell lines BeWo cells showed the strongest increase in PP13 mRNA after forskolin treatment compared to controls. Hence these cells were used to investigate the effect of varying concentrations of vitamin C, acetylsalicylic acid (ASA), Trolox) and heparin on cell fusion and PP13 and beta-hCG levels. The response to vitamin C was a dose-dependent increase in protein expression, while the other drugs showed only modest effects. Since first trimester PP13 has been shown to be significantly decreased in women subsequently developing preeclampsia, this data might point to a beneficial effect of very early vitamin C treatment of such women already in the early first trimester of pregnancy.

First-trimester markers for the prediction of pre-eclampsia in women with a-priori high risk.

OBJECTIVE: To investigate the predictive value of the combination of first-trimester serum placental protein 13 (PP13), uterine artery Doppler pulsatility index (PI) and pulse wave analysis (augmentation index at a heart rate of 75 beats per min (AIx-75)), and to evaluate concurrent and contingent strategies using this combination for assessing the risk of pre-eclampsia in high-risk women. METHODS: In this nested case-control study, serum PP13, uterine artery mean PI and AIx-75 were measured at between 11 + 0 and 13 + 6 weeks' gestation in women at increased risk of pre-eclampsia. For each case of pre-eclampsia (n = 42), five matched controls were randomly selected from the study group. Gestation specific multiples of the median (MoMs) were adjusted for body mass index, ethnicity, smoking, age and parity. MoMs were compared between cases and controls using the Wilcoxon rank sum test. Sensitivities and specificities were derived from receiver-operating characteristics curves. RESULTS: Compared with controls, women who developed pre-eclampsia had lower PP13, higher uterine artery mean PI and higher AIx-75 (P < 0.001). For a 10% false-positive rate, the best detection rate for pre-eclampsia (85.7% (95% CI, 71.5-94.6%)) and pre-eclampsia requiring delivery before 34 weeks (92.9% (95% CI, 66.1-99.8%)) was achieved by concurrent testing with all three markers. The best contingency screening sequences for pre-eclampsia were (AIx-75 --> PP13 --> mean PI) and (PP13 --> AIx-75 --> mean PI), with an 86% detection rate for false-positive rates of 9 and 10%, respectively. These two sequences would require 410 and 414 tests, respectively, compared with 756 tests in concurrent testing. CONCLUSION: Combination of first-trimester PP13, uterine artery mean PI and pulse-wave analysis is promising for the prediction of pre-eclampsia in women at increased a-priori risk and may be useful in clinical practice. Contingency screening achieved similar detection rates to concurrent testing, but required almost 50% fewer tests, making it a more cost-effective option.

IFPA meeting 2008 workshops report.

Workshops are an important part of the IFPA annual meeting. At the IFPA meeting 2008 diverse topics were discussed in 12 themed workshops. Topics covered included: immunology of placentation; galectins and trophoblast invasion; signaling in implantation and invasion; markers to identify trophoblast subpopulations; placental pathology; placental toxicology; stereology; placental transport of fatty acids; placental mesenchymal stem cells; comparative placentation; trophoblast and neoplasia; trophoblast differentiation. This report is a summary of the various topics covered.

Placental protein 13 as an early marker for pre-eclampsia: a prospective longitudinal study.

OBJECTIVE: To assess the value of placental protein 13 (PP13) as an early marker of pre-eclampsia. DESIGN: Sequential blood samples were obtained from women with singleton viable pregnancies at 6-10, 16-20 and 24-28 weeks of gestation. Samples were tested for PP13 using a solid-phase sandwich enzyme-linked immunosorbent assay. Levels were expressed as multiples of the medians (MoM) of the unaffected population. The slope or rate of change in PP13 concentration per week of gestation was also calculated. SETTING: Thirty-five prenatal care community clinics. SAMPLE: In total, 1,366 women were recruited, and subsequently, 20 were diagnosed with pre-eclampsia, 41 with gestational hypertension and 1,178 were unaffected. MAIN OUTCOME MEASURES: Sensitivity and specificity of screening with PP13 at each gestational period and of PP13 level combined with the slope of PP13 between two testing periods. RESULTS: At 6-10 gestational weeks, PP13 levels were significantly lower among the pre-eclampsia group with a median 0.28 MoM (95% CI 0.15-0.39, P < 0.004). Using a cutoff of 0.40 MoM, the sensitivity was 80%, false-positive rate (FPR) was 20% and odds ratio was 16.0 (95% CI 5.3-48.4). Combining MoM of 6-10 weeks and slope between 6-10 and 16-20 weeks, the sensitivity was 78%, the FPR was 6% and odds ratio was 55.5 (95% CI 18.2-169.2). The gestational hypertension group was not different from the normal group. CONCLUSIONS: PP13 in the first trimester alone or in combination with the slope between the first and the second trimesters may be a promising marker for assessing the risk of pre-eclampsia.

First-trimester maternal serum PP-13, PAPP-A and second-trimester uterine artery Doppler pulsatility index as markers of pre-eclampsia.

OBJECTIVE: To evaluate whether measurement of maternal serum placental protein-13 (PP-13) and pregnancy-associated plasma protein-A (PAPP-A) at 11 + 0 to 13 + 6 weeks of gestation alone or in combination with second-trimester uterine artery pulsitility measured by Doppler velocimetry is useful in predicting those women who will develop pre-eclampsia METHODS: This was a nested case-control study of pre-eclampsia cases with controls matched for gestational age and storage time for the maternal serum. Samples were collected as part of a first-trimester prenatal chromosomal anomaly screening program and were routinely tested for PAPP-A. PP-13 was tested using an enzyme linked immunosorbent assay (ELISA) by an examiner who was blinded to pregnancy outcome. All patients also underwent uterine artery Doppler flow velocimetry to measure the mean pulsatility index (PI) at 22-24 weeks' gestation. RESULTS: There were 446 controls and 44 cases with early pre-eclampsia where delivery was induced prior to 35 weeks. In addition there were a further 44 cases with pre-eclampsia in which delivery was not induced before term. Median PP-13 levels for controls, all cases and early pre-eclampsia cases were 176.9, 121.9 and 111.7 pg/mL, with multiples of the median (MoMs) of 1.00, 0.69 and 0.63, respectively (P < 0.001). PAPP-A MoMs were 1.00, 0.89 (P = 0.076) and 0.89 (P = 0.042) and mean PIs were 1.0, 1.6 (P < 0.001) and 1.7 (P < 0.001) for controls, all cases and early cases, respectively. Receiver-operating characteristics (ROC) curve analysis for either all cases or early cases vs. controls yielded areas under the curve for PP-13, PAPP-A and PI respectively of 0.68 (95% CI, 0.61-0.74; P < 0.001), 0.56 (95% CI, 0.49-0.63; P = 0.076) and 0.79 (95% CI, 0.72-0.87; P < 0.001) for all cases and 0.71 (95% CI, 0.63-0.79; P < 0.001), 0.59 (95% CI, 0.51-0.68; P = 0.076) and 0.86 (95% CI, 0.77-0.94; P < 0.001) for early cases. At a specificity set to 0.80 the sensitivities were 0.50, 0.23 and 0.76 for PP-13, PAPP-A and PI in the early cases and 0.44, 0.24 and 0.73 in all cases. Combining PP-13 and PI using logistic regression analysis yielded an area under the curve of 0.84 (95% CI, 0.78-0.90; P < 0.001) and a sensitivity of 0.74 in all cases, and 0.90 (95% CI, 0.84-0.96; P < 0.001) and a sensitivity of 0.79 for early cases. PAPP-A with PI gave an area under the curve of 0.82 (95% CI, 0.76-0.90; P < 0.001) and a sensitivity of 0.76 in all cases. Combining PAPP-A with PP-13 and PI did not add significantly to the sensitivity. CONCLUSION: First-trimester PP-13 levels may be useful in predicting pre-eclampsia and early pre-eclampsia, and the accuracy of the method increases when coupled with second-trimester Doppler PI measurement. First-trimester PAPP-A provides some prediction for pre-eclamspia when combined with PI but does not add to the prediction of early pre-eclampsia when PP-13 and PI are used together. Further studies are required to establish the real value of PP-13 in first-trimester screening for pre-eclampsia.

A novel approach to first-trimester screening for early pre-eclampsia combining serum PP-13 and Doppler ultrasound.

OBJECTIVE: To investigate the value of maternal serum placental protein 13 (PP-13) measurement and uterine artery Doppler during first-trimester screening in the prediction of early pre-eclampsia. METHODS: This was a nested case-control prospective study of pregnancies at 11 + 0 to 13 + 6 weeks of gestation. The pulsatility index (PI) of blood flow in the uterine arteries and the maternal serum concentration of PP-13 were measured in 10 women who went on to develop pre-eclampsia that necessitated delivery before 34 weeks, and in 423 unaffected women. Results were expressed as multiples of the gestation-specific median in controls (MoM). A logistic regression model was used to predict detection and false-positive rates. RESULTS: In the cases that developed pre-eclampsia requiring delivery before 34 weeks, compared with the unaffected pregnancies, the median uterine artery PI was higher (1.43 MoM) and the median serum PP-13 level was lower (0.07 MoM; P < 0.001, Wilcoxon rank sum test for both). Modeling predicted that for a 90% detection rate of pre-eclampsia requiring delivery before 34 weeks, the false-positive rate of screening by PP-13 was 12%, by uterine artery PI was 31% and by a combination of the two methods was 9%. A policy of contingency screening, whereby all women are screened by maternal serum PP-13 and only the 14% at highest risk are then screened by Doppler, achieved a detection rate of 90% with an overall false-positive rate of 6%. CONCLUSION: Effective screening for pre-eclampsia requiring delivery before 34 weeks can potentially be provided by assessment of a combination of maternal serum PP-13 and uterine artery Doppler in the first trimester of pregnancy.

Placental protein 13 (PP-13): effects on cultured trophoblasts, and its detection in human body fluids in normal and pathological pregnancies.

Placental tissue protein 13 (PP-13), one of the 56 known placental proteins identified till today, was purified from placentas obtained from women at delivery, and used to evoke antibodies against it. The purified PP-13 was lysed to peptides, which were sequenced, leading to the full-length cDNA sequencing and its expression in Escherichia coli. Sequence analysis in databases showed homology to the galectin family. Of the various antibody preparations developed, a pair of monoclonal antibodies (MAbs) coupled to the recombinant PP-13 (PP-13-R) was used for the immunodetection of PP-13 in pregnant women's serum with the solid-phase ELISA format. With a dynamic range of 25-500 pg/mL with no background in non-pregnant women's serum and men's serum, the ELISA test was suitable for the detection of PP-13 in the 1st, 2nd, and 3rd trimesters. PP-13 levels slowly increase during pregnancy. In the 1st trimester, lower than normal PP-13 levels were found in fetal growth restriction (IUGR), preeclampsia (PE), and particularly in early PE (<34 weeks of gestation). In the 2nd and 3rd trimesters, higher than normal concentrations were found in PE, IUGR and in preterm delivery (PTD). Application of PP-13 to cultured trophoblasts elicited depolarization carried by calcium ions, followed by liberation of linoleic and arachidonic acids from the trophoblast membrane, and a subsequent elevation of prostacyclin and thromboxane. These effects were negligible when PP-13 derived from the placentas of patients with IUGR, PE or PTD was used. The results are discussed in view of the potential utilization of PP-13 for early serum screening to assess the risk to develop placental insufficiency, coupled to a differential analysis of the various pathologies by analyzing cultured trophoblasts.

Calcitriol therapy modulates the cellular immune responses in hemodialysis patients.

We studied the in vitro and in vivo effects of calcitriol (1,25D) on the cellular immune responses in 19 hemodialysis (HD) patients. In vitro 5-day treatment with 1,25D markedly reduced the HLA-DR expression by peripheral blood CD14(+) monocytes from both HD patients and normal subjects in a similar fashion. The HLA-DR expression by monocytes and the phorbol myristate acetate (PMA)-induced superoxide production (SOP) by neutrophils were significantly higher in the HD patients than in the normal subjects (p < 0.01 and p < 0.05, respectively). The phagocytic activity in the HD patients was significantly lower than that in the normal subjects (p < 0.05). Moreover, the mitogen response of HD peripheral blood lymphocytes against pokeweed mitogen (PWM) was significantly lower than that of the controls (p < 0.01) but was only slightly and insignificantly lower against Con A. Oral 1,25D pulse therapy resulted in a marked decrease in the HLA-DR expression by peripheral blood monocytes 2 and 4 days after the first 1,25D administration (p < 0.01) in HD patients. Moreover, the treatment significantly enhanced the PMA-induced SOP 2 days after the treatment (p < 0.01). However, the phagocytic activity by neutrophils and the mitogen responses to Con A and PWM by lymphocytes were not significantly affected by this treatment. These results suggest that 1,25D plays a significant role in the regulation of both the monocyte and neutrophil functions in HD patients.