Transfer and metabolism of prostaglandin E(2)in the dual perfused human placenta

Lipopolysaccharide differently affects prostaglandin E2 levels in fetal and maternal compartments of perfused human term placenta

The aim of the present study was to examine the effect of lipopolysaccharide (LPS) on the levels of prostaglandin E(2) (PGE(2)) in the perfusates of the fetal and the maternal compartments of perfused human term placental tissue. Term placentas were perfused for 10h in the absence [control, (n=4)] and presence of LPS [LPS=1 microg/kg perfused placental tissue, (n=4)] in the maternal reservoir. Perfusate samples from the fetal and the maternal circulations were collected every 30 min and examined for PGE(2) levels by radio-immunoassay. PGE(2) levels in the fetal circulation were gradually increased reaching significant peak value of 479+/-159 pg/ml, as compared to PGE(2) levels in the maternal circulation (140+/-146 pg/ml) (p<0.05). After 10 hours of perfusion with control medium, PGE(2) levels in the maternal circulation (347+/-144 pg/ml) were significantly higher as compared to the fetal circulation (150+/-57 pg/ml) (p<0.05). In presence of LPS, PGE(2) levels in the fetal circulation increased reaching a peak value of 1028+/-663 pg/ml after 240 min of perfusion. The levels of PGE(2) in the control group after 240 min of perfusion were significantly lower (156+/-77 pg/ml) (p<0.05). No significant differences were detected in the levels of PGE(2) in the perfusate of the maternal compartment in presence of LPS, as compared to control. Our results suggest that the placenta may play an important role in maintaining high levels of PGE(2) in the fetal circulation and low PGE(2) levels in the maternal circulation during normal pregnancy. Moreover, placental PGE(2) release into the fetal and the maternal circulations may be differently affected in presence of intra-uterine infection/inflammation.

Arachidonic acid stimulates internalisation of leptin by human placental choriocarcinoma (BeWo) cells

Arachidonic acid at 100 nM stimulated internalisation of 125I-leptin in human placental choriocarcinoma (BeWo) cells by 3-fold compared with controls. In contrast, eicosapentaenoic acid at similar concentration decreased internalisation of leptin by 2-fold. Use of ibuprofen and indomethacin (inhibitors of prostaglandin synthesis) inhibited the stimulatory effect of arachidonic acid. Prostaglandin E(2), a cyclooxygenase metabolite of arachidonic acid, stimulated internalisation of leptin by these cells. All these data demonstrate that stimulation of leptin internalisation by arachidonic acid in placental trophoblasts may be mediated via prostaglandin E(2).

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in human fetal testis and ovary

Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) are major regulators of tissue remodelling of the extracellular matrix (ECM) and may also be involved in the control of growth factor availability. We have investigated their production and localization in the developing human gonad during mid-gestation using zymographic techniques and immunohistochemistry. The secretion of MMP-2, MMP-9 and all four TIMP was demonstrated from both testis and ovary, with the predominant gelatinase produced by both being MMP-2. In the testis, MMP-1, MMP-2, MMP-9 and all TIMP family members were localized to the interstitium and to varying degrees within the tubules. MMP-9 and TIMP-4 were abundant in both Sertoli cells and gonocytes and MMP-1 and TIMP-1 were localized in particular to Sertoli cells. In the ovary, all TIMP and MMP-1, MMP-2 and MMP-9 were localized to the oogonium/oocyte cytoplasm with varying intensities and MMP-1, TIMP-2 and TIMP-3 were also detected in the ovarian stroma. This study demonstrates that MMP-1, MMP-2, MMP-9 and all TIMP family members are secreted by the developing ovary and testis and are localized to specific cell and tissue sites. MMP and TIMP are likely to play a role in ECM remodelling during gonadal development and also in the cell and matrix interactions that control a range of cellular functions.