Polymorphisms and Plasma Level of Transforming Growth Factor-Beta 1 and Risk for Preeclampsia: A Systematic Review

<div><p>Background</p><p>Transforming growth factor-beta 1 (TGF-β1) is thought to be involved in the pathogenesis of preeclampsia (PE), but the results are inconsistent among studies. This article aims to compile an overview of the studies about the associations of TGF-β 1 polymorphism and plasma level with PE risk and to provide recommendations for future research.</p><p>Methods and Results</p><p>The databases PubMed, Embase and Web of Science were searched up to December 2013. Five studies investigating the associations of four polymorphisms with the risks of PE were involved. A meta-analysis was conducted for the 869T>C polymorphism and PE risk. The results show that genotype TT of 869T>C polymorphism is a protective factor of PE (pooled odds ratio = 0.73, 95% CI: 0.56, 0.95). Eight case-control studies reported the plasma level of TGF-β 1. The substantial heterogeneity among studies may be attributed to the differences in the blood sample processing and the TGF-β 1 analysis kits. The results suggest that plasma TGF-β 1 level in the second trimester was significantly lower in the PE group than in the normal pregnancy group, but was significantly higher in the PE group during the third trimester.</p><p>Conclusions</p><p>The current results support that the TGF-β 1 869 T>C polymorphism was associated with the risk of PE. However, the number of eligible studies is small and more studies are needed to clarify whether this association can be detected on larger sample sizes and different populations. Owing to the heterogeneity between studies, no conclusion on the association between plasma TGF-β 1 level and PE risk can be drawn from this review. Further studies about the TGF-β 1 levels at different stages of pregnancy and the development of TGF-β 1 assay methodology are required to reveal the role of TGF-β 1 in the pathological development of PE.</p></div

Characteristics of studies on plasma TGF-beta 1 levels and PE included in the systematic review.

a<p>Data are presented as mean±standard deviation or median (25–75 percentile).</p

Meta-analysis for the association of 869 T>C polymorphism with PE risk under a dominant model (TT vs. (TC+CC)) using a fixed-effects model.

<p>Meta-analysis for the association of 869 T>C polymorphism with PE risk under a dominant model (TT vs. (TC+CC)) using a fixed-effects model.</p

Main results of the pooled ORs in meta-analysis for the association between the 869 T>C polymorphism and PE.

<p>*Pooled with fixed effect model.</p

PRISMA flow diagram of study selection process (a) articles involving TGF-beta 1 genetic variants and (b) articles involving plasma concentration of TGF-beta1.

<p>PRISMA flow diagram of study selection process (a) articles involving TGF-beta 1 genetic variants and (b) articles involving plasma concentration of TGF-beta1.</p

Detailed characteristics of all eligible studies for the association with TGF gene polymorphisms and PE.

<p>*Genotype for 869 T>C, TT/TC/CC; 915 G>C, GG/GC/CC; 800 G>A, GG/GA/AA; 509 C>T, CC/CT/TT.</p>a<p>Significant differences was found in allelic frequencies between preeclamptic and control groups.</p>b<p>No significant differences was found in allelic frequencies between preeclamptic and control groups.</p

Additional file 3: Figure S2. of Serum level and polymorphisms of retinol-binding protein-4 and risk for gestational diabetes mellitus: a meta-analysis

The results of sensitivity analysis of serum RBP4 level with GDM risk. (TIFF 8567 kb

Additional file 1: Table S1. of Serum level and polymorphisms of retinol-binding protein-4 and risk for gestational diabetes mellitus: a meta-analysis

Adjusted covariates of all eligible studies for the association with serum RBP4 levels and GDM. (DOCX 18 kb

Additional file 4: Figure S3. of Serum level and polymorphisms of retinol-binding protein-4 and risk for gestational diabetes mellitus: a meta-analysis

The results of sensitivity analysis of rs3758539 (GG vs. GA + AA) with GDM risk. (TIFF 5448 kb

Comparison of distribution of inter-twin birth weight discordance (%) between those pregnant women with hepatitis C and those without, United States, 2011−2015.

Comparison of distribution of inter-twin birth weight discordance (%) between those pregnant women with hepatitis C and those without, United States, 2011−2015.</p