Lower HLA-G levels in extravillous trophoblasts of human term placenta in gestational diabetes mellitus than in normal controls

The non-classical human leucocyte antigen (HLA) class I molecule HLA-G is widely known to play a major role in feto-maternal tolerance. We tested the hypothesis that HLA-G expression is altered in placentas of women with gestational diabetes mellitus (GDM) in a specific pattern that depends on fetal sex. HLA-G expression was analysed in a total of 80 placentas (40 placentas from women with GDM and 40 healthy controls) by immunohistochemistry using the semi-quantitative immunoreactive score (IRS). Double immunofluorescence staining identified the cells expressing HLA-G in the decidua and allowed evaluation of the expression pattern. We found a significant (p < 0.001) reduction of HLA-G expression in extravillous cytotrophoblasts (EVTs) in the placentas of women with GDM as compared to the healthy controls and were able to demonstrate that this downregulation was not due to a loss of cell number, but to a loss of expression intensity. A special change in the cell pattern of EVTs was observed, with these cells showing an obvious decrease in HLA-G expression on their cell surface. No significant differences according to fetal sex were found. These data show a possible association between decreased HLA-G expression and presence of GDM and provide new insights into altered placental function in women with GDM.

RXRα is upregulated in first trimester endometrial glands of spontaneous abortions unlike LXR and PPARγ

Nuclear receptors are necessary for uterine invasion of the trophoblast and therefore important for maintaining a viable pregnancy. The aim of this study was to investigate the expression pattern and frequency of LXR, PPARγ and RXRα under physiological circumstances and in spontaneous abortions in endometrial glands and decidual tissue cells. A total of 28 (14 physiologic pregnancies/14 spontaneous abortion) human pregnancies in first trimester were analyzed for expression of the nuclear receptors LXR, RXRα and PPARγ. Expression changes were evaluated by immunohistochemistry in decidual tissue and endometrial glands of the decidua. RXRα expression was up-regulated in the endometrial glands of spontaneous abortion (P<0.015). Similar up regulation of RXRα was found in decidual tissue (P<0.05). LXR and PPARγ expression was unchanged in spontaneous abortion. By Correlation analysis we found a trend to positive correlation of LXR and PPARγ (Spearman correlation coefficient r=0.56, P=0.07) in endometrial glands. In decidual tissue, we found significant negative correlation in the control group, for the combination of RXRα and PPARγ (Spearman correlation coefficient r=0.913, P=0.03). Our data show that RXRα expression is increased in miscarriage in endometrial glands and correlation analysis showed that negative correlation between RXRα and PPARγ disappears in miscarriage. This shift is supposable responsible for the loss of regular function in trophoblast and embryonic tissue.

GDM Alters Expression of Placental Estrogen Receptor α in a Cell Type and Gender-Specific Manner

OBJECTIVE

The nuclear receptor estrogen receptor α (ERα) is one of the key players in energy balance, insulin resistance, and trophoblast differentiation. We tested the hypothesis that gestational diabetes mellitus (GDM) alters expression of placental ERα in a cell type-specific manner and that this regulation may involve epigenetic changes.

STUDY DESIGN

Expression of ERα was analyzed by immunohistochemistry using the semiquantitative immunoreactive score in 80 placentas (40 GDM/40 controls). Quantitative real-time polymerase chain reaction (PCR) measured ERα messenger RNA (mRNA) in decidual tissue. Methylation-specific PCR was performed to analyze cytosine-phosphatidyl-guanine-island methylation of the ERα promoter.

RESULTS

Expression of ERα protein is upregulated (P = .011) in GDM in extravillous trophoblasts but not in syncytiotrophoblast. Gestational diabetes mellitus downregulated ERα in decidual vessels only in pregnancies with male but not female fetuses. Furthermore, mRNA of the ERα encoding gene estrogen receptor gene 1 (ESR1) was increased (+1.77 fold) in GDM decidua when compared to controls (P = .024). In parallel, the promoter of ESR1 was methylated only in decidua of healthy control individuals but not in GDM.

CONCLUSION

Gestational diabetes mellitus affects expression of placental ERα in a cell type-dependent way, on epigenetic level. These data link GDM with epigenetic deregulations of ERα expression and open new insights into the intrauterine programming hypothesis of GDM.

Galectin-13/PP-13 expression in term placentas of gestational diabetes mellitus pregnancies

INTRODUCTION

Gestational diabetes mellitus (GDM) is an increasing harm in pregnancy. Inflammatory processes in the placenta seem to have an influence on pathogenesis besides known factors like maternal BMI. Galectin-13 (gal-13) is an immunoregulatory protein, which is suspected to play a role in development of GDM in the placenta.

METHODS

A total of 40 placentas were obtained from women treated for gestational diabetes mellitus. Placental tissue for control group was obtained from 40 women with normal pregnancy. We investigated the protein expression of gal-13 in term placentas with immunohistochemistry and immunofluorescence. Immunohistochemical staining was analyzed with the semi-quantified IRS score. Gal-13 serum levels were performed with ELISA on a total of 20 probes from women with GDM and healthy control pregnancies in the third trimester.

RESULTS

Gal-13 was found in syncytiotrophoblast, in nuclei of syncytiotrophoblast and trophoblast cells as well in extravillous trophoblast cells of normal placentas. In GDM placentas, gal-13 expression was significantly decreased in all of these examined cell types (syncytiotrophoblast p = 0.003, nuclei of syncytiotrophoblast p = 0.007; extravillous trophoblast cells p = 0.001). The ELISA showed a significant lower gal-13 serum level in blood from pregnant women with GDM in comparison to healthy controls.

DISCUSSION

As gal-13 with its anti-inflammatory functions plays a role in regulation of maternal immune system, a lack of gal-13 may contribute to an imbalance in inflammation processes in the placenta during pregnancy and therefore influences development of GDM.

Gestational diabetes mellitus upregulates vitamin D receptor in extravillous trophoblasts and fetoplacental endothelial cells

OBJECTIVE

Gestational diabetes mellitus (GDM) is often accompanied by low maternal vitamin D, that is, calcitriol (1,25[OH]2 vitamin D3), levels. Here, we tested the hypothesis that the placental vitamin D receptor (VDR) is regulated by calcitriol and altered in GDM with distinct changes in different placental cell types. Specifically, we aimed to localize VDR in human term placentas from normal and GDM pregnancies, to quantify its cellular expression and to study in vitro its regulation by its physiological agonist calcitriol.

STUDY DESIGN

Placental tissue slides of 80 patients (40 with GDM/40 controls) were double stained for VDR and human leukocyte antigen G to identify extravillous trophoblasts (EVTs). Staining intensity was semiquantified. Quantitative real time-polymerase chain reaction and Western blotting measured VDR messenger RNA (mRNA) and protein in decidual tissue. The trophoblast cell line BeWo was used to study in vitro VDR regulation by calcitriol (0.01, 0.1, and 1 nmol/mL).

RESULTS

Vitamin D receptor protein and mRNA levels are upregulated (P < .05) in EVT (1.8-fold) as well as in placental endothelium (5.8-fold) of patients with GDM. Expression of VDR is regulated by calcitriol in a bimodal manner: high doses (0.1 and 1 nmol/mL) caused downregulation, whereas the low dose (0.01 nmol/mL) resulted in VDR upregulation.

CONCLUSION

Vitamin D receptor is upregulated in EVT and endothelium of GDM placentas. This could be due to low maternal vitamin D levels in patients with GDM because in vitro low calcitriol doses upregulate VDR in trophoblast cells.

Peroxisome proliferator-activated receptor-gamma (PPARγ) is down regulated in trophoblast cells of gestational diabetes mellitus (GDM) and in trophoblast tumour cells BeWo in vitro after stimulation with PPARγ agonists

AIMS

Peroxisome proliferator-activated receptor-gamma (PPARγ) plays an important role in insulin metabolism, trophoblast differentiation and anti-inflammatory circuits. The aim of this study was to investigate the expression of PPARγ in the placenta of patients with gestational diabetes mellitus (GDM) and the regulation of PPARγ by its agonists in trophoblast tumour cells BeWo in vitro.

METHODS

PPARγ expression in a total of 80 placentas (40 GDM/40 controls) was analysed by immunohistochemistry using the semi-quantitative immunoreactive score. Furthermore, a quantitative reverse transcription-polymerase chain reaction (PCR) was performed to determine the PPARγ mRNA-expression in both groups. We used a fused and a non-fused BeWo cell culture model for the stimulation with arachidonic acid and 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2). Afterwards PPARγ mRNA-expression was analysed by quantitative real-time PCR (RT-PCR) (TaqMan).

RESULTS

Using immunohistochemistry we identified a decreased expression of PPARγ in the syncytiotrophoblast and the extravillous trophoblast of GDM placentas compared to normal controls. Furthermore, PPARγ mRNA-expression was reduced in GDM placentas. Stimulation of BeWo cells with arachidonic acid and 15d-PGJ2 caused a downregulation of PPARγ expression.

CONCLUSION

As PPARγ is down regulated by arachidonic acid and 15d-PGJ2, the reduced PPARγ expression in GDM placentas may be due to an altered concentration of fatty acid derivates.