Effect of Lactobacillus rhamnosus GR-1 supernatant and fetal sex on lipopolysaccharide-induced cytokine and prostaglandin-regulating enzymes in human placental trophoblast cells: implications for treatment of bacterial vaginosis and prevention of preterm labor.

OBJECTIVE: The objective of the study was to determine the effect of fetal sex on the output of cytokines and prostaglandin-regulating enzymes in lipopolysaccharide (LPS) and probiotic lactobacilli-treated placental trophoblast cells. STUDY DESIGN: We examined the effect of LPS and Lactobacillus rhamnosus GR-1 supernatant in placental trophoblast cells on tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-10 using enzyme-linked immunosorbent assay and on prostaglandin-endoperoxide synthase 2 (PTGS2), 15-hydroxy prostaglandin dehydrogenase (PGDH), and toll-like receptor-4 (TLR-4) using Western blotting. Comparisons were performed using one-way analysis of variance and Student t test. RESULTS: LPS increased the output of TNF-alpha, IL-10, and PTGS2 with a greater response in male placentae. L rhamnosus GR-1 supernatant inhibited the LPS-stimulated TNF-alpha and increased IL-10. It also up-regulated expression of PGDH in female placentae and partially reduced the LPS-stimulated PTGS2 in male placentae. There was no change in IL-1beta. Expression of TLR-4 was greater in placentae of male fetuses. CONCLUSION: These findings suggest an underlying mechanism for the sex difference in the incidence of preterm birth and provide potential evidence for a therapeutic benefit of lactobacilli in reducing preterm labor.

15-Hydroxyprostaglandin dehydrogenase protein expression in human fetal membranes with and without subclinical inflammation.

Prostaglandins play a central role in the stimulation and maintenance of both term and preterm labor. 15-Hydroxyprostaglandin dehydrogenase (PGDH), localized primarily to chorion trophoblasts, is the key enzyme responsible for the metabolism of prostaglandins. In preterm chorion, levels of PGDH protein and activity were lower when compared to term and were further reduced with the presence of infection, but effects of subclinical inflammation and membrane rupture on PGDH expression are not known. Our objectives were (1) to determine the relative expression of PGDH in amnion and chorion and (2) to determine the effect of preterm premature rupture of membranes (PPROM) and (3) subclinical inflammation on PGDH protein expression in preterm fetal membranes. Fetal membranes were collected from women with idiopathic preterm labor. Patients were divided into preterm birth (1) <32 weeks with PPROM (n = 6), (2) <32 weeks with intact membranes (n = 11), (3) >or=32 and <37 weeks with PPROM (n = 10), and (4) >or=32 and <37 weeks with intact membranes (n = 10). Different antibodies were used to detect protein expression and localization of PGDH in amnion and chorion from these patients using both Western blotting and immunohistochemistry. Antibody T (AbT) localized PGDH to chorion trophoblasts, whereas antibody C (AbC) detected immunoreactive (ir) PGDH predominantly in the amnion mesenchyme. By Western blot, AbT showed a stronger 29-kDa ir-PGDH band whereas with AbC, a stronger 55-kDa ir-PGDH signal was detected. 55-kDa ir-PGDH was significantly higher in PPROM amnion, specifically in the <32 weeks group (P < .05) and with PPROM >24 hours (P < .05). No change was detected in the 29-kDa ir-PGDH in either amnion or chorion with gestational age or the presence and absence of PPROM. In addition, neither form of ir-PGDH was altered significantly with or without subclinical inflammation. ir-PGDH is detectable in both chorion trophoblasts and amnion, especially in the mesenchyme; however, the predominant form of the enzyme differs in the 2 tissues. PPROM and subclinical inflammation do not appear to affect the levels of 29-kDa ir-PGDH protein in the fetal membranes. The differential expression of 55-kDa ir-PGDH in preterm amnion with and without PPROM supports the need for a better understanding of the different forms of PGDH.

Elevated circulating insulin-like growth factor binding protein-1 is sufficient to cause fetal growth restriction.

IGF binding protein-1 (IGFBP-1) inhibits the mitogenic actions of the IGFs. Circulating IGFBP-1 is elevated in newborns and experimental animals with fetal growth restriction (FGR). To establish a causal relationship between high circulating IGFBP-1 and FGR, we have generated transgenic mice using the mouse alpha-fetoprotein gene promoter to target overexpression of human IGFBP-1 (hIGFBP-1) in the fetal liver. These transgenic mice (AFP-BP1) expressed hIGFBP-1 mainly in the fetal hepatocytes, starting at embryonic d 14.5 (E14.5), with lower levels in the gut. The expression peaked at 1 wk postnatally (plasma concentration, 474 +/- 34 ng/ml). At birth, AFP-BP1 pups were 18% smaller [weighed 1.34 +/- 0.02 g compared with 1.62 +/- 0.04 g for wild type (WT); P < 0.05], and they did not demonstrate any postnatal catch-up growth. The placentas of the AFP-BP1 mice were larger than WT from E16.5 onwards (150 +/- 12 for AFP-BP1 vs. 100 +/- 5 mg for WT at E16.5; P < 0.05). Thus, this model of FGR is associated with a larger placenta, but without postnatal catch-up growth. Overall, these data clearly demonstrate that high concentrations of circulating IGFBP-1 are sufficient to cause FGR.

Effect of intermittent umbilical cord occlusion on fetal respiratory activity and brain adenosine in late-gestation sheep.

It was hypothesized that intermittent umbilical cord occlusion (UCO) would inhibit ovine fetal breathing movements (FBM) in association with increased cerebral adenosine levels. To test this hypothesis, on two successive days during late gestation (133-134 days; term = 146 days), microdialysis samples were collected from the brains of 10 chronically instrumented fetal sheep during 2-h periods of complete UCO induced every 30 min (Day 1: 2-min UCOs; Day 2: 4-min UCOs). Control fetuses (n = 10) underwent no UCO. Tracheal pressure was measured throughout. This regimen resulted in a decrease in fetal arterial PO2 (PaO2) during each UCO to 7.3 +/- 0.8 mmHg (P<0.01; Day 1) and 8.4 +/- 1.1 mmHg (P<0.01; Day 2). Throughout each UCO period, fetal arterial pH (pHa) decreased to 7.28 +/- 0.02 (P<0.01; Day 1) and 7.11 +/- 0.07 (P<0.01; Day 2). The hourly incidence of FBM decreased significantly only on Day 2, from 38.6 +/- 4.1% to 4.1 +/- 1.6% (P<0.01). The frequency of deep isolated inspiratory efforts increased from 4.7 +/- 2.0 h(-1) to 17.6 +/- 6.1 h(-1) (P<0.05; Day 1) and from 2.2 +/- 0.9 h(-1) to 33.6 +/- 4 h(-1) (P<0.01; Day 2). The amplitude of both FBM and deep isolated inspiratory efforts increased during the UCO periods on both days. The concentration of cerebral extracellular fluid (ECF) adenosine during UCO increased by 219 +/- 215% (P<0.05; Day 1) and 172 +/- 107% (P<0.05; Day 2) over the baseline periods. In conclusion, the severity of the inhibitory effect of repeated UCO on FBM depends, in part, on the length of the occlusions. The inhibition of FBM during intermittent UCO may be mediated by the increase in ECF adenosine in the fetal brain. Furthermore, FBM and deep isolated inspiratory efforts appear to be regulated by different mechanisms.