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Low-molecular-weight heparin for prevention of placenta-mediated pregnancy complications: protocol for a systematic review and individual patient data meta-analysis (AFFIRM).

ABSTRACT: Placenta-mediated pregnancy complications include pre-eclampsia, late pregnancy loss, placental abruption, and the small-for-gestational age newborn. They are leading causes of maternal, fetal, and neonatal morbidity and mortality in developed nations. Women who have experienced these complications are at an elevated risk of recurrence in subsequent pregnancies. However, despite decades of research no effective strategies to prevent recurrence have been identified, until recently. We completed a pooled summary-based meta-analysis that strongly suggests that low-molecular-weight heparin reduces the risk of recurrent placenta-mediated complications. The proposed individual patient data meta-analysis builds on this successful collaboration. The project is called AFFIRM, An individual patient data meta-analysis oF low-molecular-weight heparin For prevention of placenta-medIated pRegnancy coMplications.We conducted a systematic review to identify randomized controlled trials with a low-molecular-weight heparin intervention for the prevention of recurrent placenta-mediated pregnancy complications. Investigators and statisticians representing eight trials met to discuss the outcomes and analysis plan for an individual patient data meta-analysis. An additional trial has since been added for a total of nine eligible trials. The primary analyses from the original trials will be replicated for quality assurance prior to recoding the data from each trial and combining it into a common dataset for analysis. Using the anonymized combined data we will conduct logistic regression and subgroup analyses aimed at identifying which women with previous pregnancy complications benefit most from treatment with low-molecular-weight heparin during pregnancy.The goal of the proposed individual patient data meta-analysis is a thorough estimation of treatment effects in patients with prior individual placenta-mediated pregnancy complications and exploration of which complications are specifically prevented by low-molecular-weight heparin.PROSPERO (International Prospective Registry of Systematic Reviews) 23 December 2013, CRD42013006249.

SUBMITTER: Rodger MA

PROVIDER: S-EPMC4094595 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature

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Low-molecular-weight heparin for prevention of placenta-mediated pregnancy complications: protocol for a systematic review and individual patient data meta-analysis (AFFIRM).

Rodger Marc A MA Langlois Nicole J NJ de Vries Johanna Ip JI Rey Evelyne E Gris Jean-Christophe JC Martinelli Ida I Schleussner Ekkehard E Ramsay Timothy T Mallick Ranjeeta R Skidmore Becky B Middeldorp Saskia S Bates Shannon S Petroff David D Bezemer Dick D van Hoorn Marion E ME Abheiden Carolien Nh CN Perna Annalisa A de Jong Paulien P Kaaja Risto R

Systematic reviews 20140626

<h4>Background</h4>Placenta-mediated pregnancy complications include pre-eclampsia, late pregnancy loss, placental abruption, and the small-for-gestational age newborn. They are leading causes of maternal, fetal, and neonatal morbidity and mortality in developed nations. Women who have experienced these complications are at an elevated risk of recurrence in subsequent pregnancies. However, despite decades of research no effective strategies to prevent recurrence have been identified, until recen ...[more]

PMID: 24969227

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Project description:Data on the temporal dynamics of human placental gene expression is scarce. We have completed the first whole-genome profiling of human placental gene expression dynamics (GeneChips, Affymetrix®) from early to mid- gestation (10 samples; gestational weeks 5 to 18) and report 154 genes with considerable change in transcript levels (FDR P<0.1). Functional enrichment analysis revealed >200 GO categories that are statistically over-represented among 105 genes with dynamically increasing transcript levels. Analysis in an extended sample (n=43; gestational weeks 5 to 41) conformed a highly significant (FDR P<0.05) expressional peak in mid-gestation placenta for ten genes: BMP5, CCNG2, CDH11, FST, GATM, GPR183, ITGBL1, PLAGL1, SLC16A10, STC1. A central hypothesis of our study states that the aberrant expression of genes characteristic to mid-gestation placenta may contribute to affected fetal growth, maternal preeclampsia (PE) or gestational diabetes (GD). The gene STC1 coding for Stanniocalcin 1 (STC1) was identified with a sharp placental expressional peak in mid-gestation, increased mRNA levels at term and significantly elevated STC1 protein levels in post-partum maternal plasma in all pregnancy complications. The highest STC1 levels were identified in women, who developed simultaneously PE and delivered an SGA baby (median 731 vs 418 pg/ml in controls; P=0.001). CCNG2 and LYPD6 exhibited significantly increased placental mRNA expression and enhanced intensity of immunohistochemistry staining in placental sections all studied in GD and PE cases. Aberrant expression of mid-gestation specific genes in pregnancy complications at term indicates the importance of the fine-scale tuning of the temporal dynamics of transcription regulation in placenta. Observed significantly elevated plasma STC1 in complicated pregnancies warrants further investigations of its potential as a biomarker. Interestingly, a majority of genes with high expression in mid-gestation placenta have also been implicated in adult complex disease. This observation promotes a recently opened discussion on the role of placenta in developmental programming. 4 samples; this submission is extension of our earlier study (accession GSE22490).

Project description:Despite the importance of placenta in mediating rapid physiological changes in pregnancy, data on temporal dynamics of placental gene expression are limited. We completed the first transcriptome profiling of human placental gene expression dynamics (GeneChips, Affymetrix®; ~47,000 transcripts) from early to mid-gestation (n = 10; gestational weeks 5-18) and report 154 genes with significant transcriptional changes (ANOVA, FDR P<0.1). TaqMan RT-qPCR analysis (n = 43; gestational weeks 5-41) confirmed a significant (ANOVA and t-test, FDR P<0.05) mid-gestational peak of placental gene expression for BMP5, CCNG2, CDH11, FST, GATM, GPR183, ITGBL1, PLAGL1, SLC16A10 and STC1, followed by sharp decrease in mRNA levels at term (t-test, FDR P<0.05). We hypothesized that normal course of late pregnancy may be affected when genes characteristic to mid-gestation placenta remain highly expressed until term, and analyzed their expression in term placentas from normal and complicated pregnancies [preeclampsia (PE), n = 12; gestational diabetes mellitus (GDM), n = 12; small- and large-for-gestational-age newborns (SGA, LGA), n = 12+12]. STC1 (stanniocalcin 1) exhibited increased mRNA levels in all studied complications, with the most significant effect in PE- and SGA-groups (t-test, FDR P<0.05). In post-partum maternal plasma, the highest STC1 hormone levels (ELISA, n = 129) were found in women who had developed PE and delivered a SGA newborn (median 731 vs 418 pg/ml in controls; ANCOVA, P = 0.00048). Significantly higher expression (t-test, FDR P<0.05) of CCNG2 and LYPD6 accompanied with enhanced immunostaining of the protein was detected in placental sections of PE and GDM cases (n = 15). Our study demonstrates the importance of temporal dynamics of placental transcriptional regulation across three trimesters of gestation. Interestingly, many genes with high expression in mid-gestation placenta have also been implicated in adult complex disease, promoting the discussion on the role of placenta in developmental programming. The discovery of elevated maternal plasma STC1 in pregnancy complications warrants further investigations of its potential as a biomarker.

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Dataset Information

Low-molecular-weight heparin for prevention of placenta-mediated pregnancy complications: protocol for a systematic review and individual patient data meta-analysis (AFFIRM).

Publications

Low-molecular-weight heparin for prevention of placenta-mediated pregnancy complications: protocol for a systematic review and individual patient data meta-analysis (AFFIRM).

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