Galectin 2 expression in placentas of pre-eclamptic patients

Introduction:

Preeclampsia (PE), is well known as a pregnancy specific disorder associated with maternal inflammation and insufficient placentation. Galectin 2 (gal-2) has been shown to have important regulatory functions in monocyte and macrophage function as well as in angiogenesis.

Methods:

Placental tissues were obtained from 14 women with regular pregnancies and 13 women with PE, with a mean date of delivery in the PE group of 34 ± 3.2 and in the control group 39 ± 1.4 weeks of gestation. The tissue samples were stained for immunohistochemistry and immunofluorescence and analyzed using the IRS score to evaluate gal-2 expression in placental tissue.

Results:

Down regulation of gal-2 protein expression in placental tissue from pre-eclamptic patients was shown using IRS scoring. It revealed a 1.3 -fold decrease in gal-2 staining intensity of extravillous cytotrophoblast cells (EVT) in cases of pre-eclampsia (2.8 ± 2.3) compared with control placentas (3.8 ± 1.6). Staining intensity of syncytiotrophoblast is 2.0-fold decreased in cases of pre-eclampsia (1.9 ± 2.3) compared with control placentas (3.8 ± 1.6). Results from rt-PCR also showed significantly lower gene expression of gal-2 in PE placentas compared to controls. No difference was shown between early onset PE (before 34+0 weeks) and late onset PE (after 34+0 weeks).

Conclusion:

As EVT and syncytiotrophoblast show both decreased expression of gal-2 in cases of PE compared to the control group it is unclear whether this lowered expression is causative for PE or a result of its pathophysiology. Further investigation is needed to fully understand the role of gal-2 concerning PE and other gestational diseases.

Fig. 1

Galectin-2 expression is intense in normal syncytiotrophoblasts as shown in A (magnification 250x). In preeclamtic placental tissue, the syncytiotrophoblast shows significantly reduced staining (B, magnification 250x). A summary of the staining results is presented as Box-Plot (C, The boxes represent the range between the 25th and 75th percentiles with a horizontal line at the median. The bars delineate the 5th and 95th percentiles. The circle indicates values more than 1.5 box lengths, and the asterisk indicates values more than 3.0 box lengths from the 75th percentile). Gal-2 staining in early onset compared to late preeclampsia is shown in D. Description of Box Plots as for C.