Transfer of inflammatory cytokines across the placenta

OBJECTIVE: The purpose of this study was to determine whether the placental transfer of interleukin (IL)-1alpha, IL-6, and tumor necrosis factor-alpha (TNF-alpha) occurs. METHODS: Four normal-term placentas were perfused for maternal-fetal transfer of the cytokines, 2 placentas for fetal-maternal transfer, and 4 additional placentas were used for an endogenous control. The ex vivo isolated cotyledon human placental perfusion model was used. The reference compound antipyrine was used to determine the transport fraction and clearance index of the cytokines. The cytokines were added to either the maternal or fetal circulations, and samples were collected for 1 hour in a constant-flow open circulation. Cytokine levels were compared between the study and control placentas. Concentrations of the cytokines were measured by sandwich enzyme immunoassay. RESULTS: The clearance index for the maternal-fetal transfer of IL-1alpha and TNF-alpha was 0.001, suggesting minimal transfer to the fetal circulation. The clearance index for IL-6 was 0.30, indicating transfer to the fetal circulation. When the cytokines were added to the fetal circulation, the clearance index for IL-1alpha was 0.001, again indicating minimal transfer. The clearance index for TNF-alpha in the fetal-maternal study was not determined. IL-6 had a clearance index of 0.23, which was similar to that observed with maternal-fetal transfer. IL-6 concentrations in the study placentas were higher than the concentrations found in the controls. CONCLUSION: There appears to be bidirectional transfer of IL-6 in the healthy-term human placental perfusion model. LEVEL OF EVIDENCE: II-2     

细胞因子与胎儿宫内发育受限胎盘凋亡相关性研究

目的探讨胎儿宫内生长受限(FGR)中细胞因子对胎盘细胞凋亡的调节。方法 20例FGR组和25例足月正常体重儿(对照组),采用放射免疫分析法测定脐血中表皮生长因子(EGF),肿瘤坏死因子a(TNF—α)浓度。末端脱氧核苷酸转移酶介导的dUTP缺口末端标记(TUNEL)法检测胎盘细胞凋亡指数(AI)。结果与对照组比较,FGR组脐血EGF浓度明显降低(P<0.01),TNF—α明显升高(P<0.05),胎盘AI明显升高(P<0.01)。FGR组中脐血EGF浓度与胎盘细胞AI呈负相关(P<0.05),TNF—α与AI呈正相关(P<0.05)。在正常对照组中EGF、TNF—α与AI无相关性(P>0.05)。结论FGR脐血中EGF水平降低,TNF—a升高,可能引起胎盘凋亡细胞增加,抑制胎儿生长。     

The relationship between acute inflammatory lesions of the preterm placenta and amniotic fluid microbiology.

OBJECTIVE: Our objective was to determine the relationship between microbial invasion of the amniotic cavity and the presence and severity of acute inflammatory lesions in the placenta. STUDY DESIGN: Placental histologic and amniotic fluid microbiologic studies were performed in 92 consecutive patients who were admitted with preterm labor and intact membranes and delivered within 48 hours after amniocentesis. RESULTS: The prevalence of a positive amniotic fluid culture was 38% (35 of 92). There was a strong association between the presence and severity of inflammation in the amnion, chorion-decidua, umbilical cord, and chorionic plate and the results of the amniotic fluid culture (p less than 0.0001 for each tissue section). Three patterns of inflammation of the chorion-decidua were identified: marginating, nonmarginating, and a mixed pattern. The marginating and the mixed patterns of inflammation were strongly associated with the presence of a positive amniotic fluid culture. Acute inflammation of the chorionic plate was the most sensitive indicator of a microbial invasion of the amniotic cavity (sensitivity 96.6%), and funisitis and umbilical vasculitis had the highest specificity (85.7%). CONCLUSION: The presence of acute inflammatory lesions of the chorioamniotic membranes can serve as a marker of microbial invasion of the amniotic cavity.     

Cerebral palsy and chorioamnionitis: the inflammatory cytokine link.

Cerebral palsy remains a significant cause of perinatal morbidity in medically developed countries. Human epidemiologic data suggest a relationship between cerebral palsy and chorioamnionitis mediated by proinflammatory cytokines. This association has been confirmed by experimental data from human and animal research that demonstrate an increase in cytokine levels in the amniotic fluid of cases of white matter damage. Recent evidence suggests this damage is the result of a fetal inflammatory response initiated in response to placental inflammation. The strong association between cerebral palsy and chorioamnionitis warrants additional investigation into the mechanisms by which white matter damage is initiated and into possible neuroprotective treatments to prevent the development of cerebral palsy.     

The effects of hypoxia and hyperoxia on fetal-placental vascular tone and inflammatory cytokine production.

OBJECTIVE: To determine the effects of fetal hypoxia and hyperoxia on placental vascular tone and production of interleukin-6 and tumor necrosis factor-alpha. STUDY DESIGN: The maternal and fetal circulation of 2 cotyledons from 5 human placentas were perfused for 4 hours. The fetal circulation of 1 cotyledon was perfused with hypoxic Hanks' balanced salt solution; the other was perfused with hyperoxic Hanks' balanced salt solution. Fetal vascular pressures were recorded every 10 minutes, and fetal vein effluents were collected hourly. RESULTS: Fetal-placental vascular perfusion pressure was reduced from baseline during hypoxic conditions. Cytokine concentrations were elevated during hyperoxic conditions compared with hypoxic conditions, with significant differences achieved at 2, 3, and 4 hours for interleukin-6 and at 4 hours for tumor necrosis factor-alpha. CONCLUSION: Fetal-placental vasodilation may be a compensatory mechanism to improve hypoxic conditions. Supraphysiologic oxygenation may contribute to the fetal inflammatory response syndrome and to the development of cerebral palsy.     

PPARγ不同配体对LPS诱导人滋养细胞炎症细胞因子的调节

目的:探讨PPARγ的天然激动配体15-d-PGJ2和合成配体Troglitazone对人滋养细胞IL-6、IL-8和TNF-α分泌的调节及其可能的机制。方法:以LPS刺激体外培养的滋养细胞作为炎症细胞模型,细胞经10mg/L的LPS与30μmol/L的15-d-PGJ2和Tro-glitazone单独或联合处理,培养6h后收集上清,通过ELISA定量检测IL-6、IL-8和TNF-α的分泌,通过Western blot检测处理后细胞NF-B蛋白活性的变化。结果:滋养细胞经15-d-PGJ2和Troglitazone处理后,LPS诱导的IL-6、IL-8和TNF-α分泌,分别下降97.53%,93.10%,90.62%和92.68%,73.85%,91.80%,差异均有显著统计学意义(P<0.05),且15-d-PGJ2可抑制NF-B蛋白活性,而Troglitazone无此作用。结论:PPARγ被配体激活后可调节人滋养细胞炎症细胞因子的分泌,部分机制可能是通过抑制NF-B蛋白活性实现的,因此,从平衡炎症反应角度为预防和治疗子痫前期提供了实验依据。     

The thrombogenic effect of an inflammatory cytokine on trophoblasts from women with preeclampsia

OBJECTIVE: This study was undertaken to investigate whether the increased thrombogenic potential of cytotrophoblastic cells of women with preeclampsia can be accounted for by increased rates of apoptosis. STUDY DESIGN: Cytotrophoblasts were isolated from the placenta of (a) nulliparous women without hypertensive disease who were delivered at term and (b) nulliparous women with preeclampsia. The cytotrophoblasts were identified by morphology, and cytokeratin and gonadotropin-releasing hormone positivity. The inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) was added to cytotrophoblasts in vitro and incubated for 24 hours. Tissue factor antigen, activity, and amount of apoptosis were evaluated both before and after TNF-alpha stimulation. RESULTS: TNF-alpha simulation significantly increased tissue factor activity both in the cytotrophoblasts of women with (0.08 +/- 0.04 pmol/min/10 6 cells to 0.53 +/- 0.19 pmol/min/10 6 cells) and without (0.07 +/- 0.04 pmol/min/10 6 cells to 0.30 +/- 0.16 pmol/min/10 6 cells) preeclampsia. TNF-alpha stimulation of the cytotrophoblasts also significantly increased tissue factor antigen in the cytotrophoblasts of both groups of women (3.6 +/- 0.9 fmol/10 6 cells to 34.0 +/- 7.5 fmol/10 6 cells, and 7.5 +/- 1.4 fmol/10 6 cells to 25.4 +/- 2.2 fmol/10 6 cells, respectively). For both tissue factor antigen and activity, the magnitude of increase after stimulation was significantly greater in the preeclamptic cytotrophoblasts. In contrast, both normal and preeclamptic cytotrophoblasts showed similar increases in their apoptotic indices (approximately 2-fold) after induction by TNF-alpha. CONCLUSION: The greater response of tissue factor activity and antigen to TNF-alpha by preeclamptic cytotrophoblasts cannot be accounted for by the increase in apoptosis. These data suggest that preeclamptic cytotrophoblasts are inherently more thrombogenic and more sensitive to TNF-alpha stimulation.     

Pentoxifylline inhibits lipopolysaccharide-induced inflammatory mediators in human second trimester placenta explants

BackgroundIntrauterine infection and inflammation during pregnancy, which leads to up-regulation of inflammatory cytokines and prostaglandin synthesis, has been implicated in the pathogenesis of preterm delivery and other pregnancy complications. Effective preventive and therapeutic strategies to reduce these outcomes are lacking to date. Pentoxifylline (PTX) is a non-specific phosphodiesterase inhibitor which raises intracellular cyclic adenosine monophosphate and decreases production of pro-inflammatory mediators while enhancing anti-inflammatory cytokines. We hypothesized that pentoxifylline will decrease lipopolysaccharide (LPS)-induced pro-inflammatory cytokines production in human placental explants.MethodsPlacental explants derived from normal second trimester human placentas were treated with PTX, stimulated with LPS and cultured at 37 °C in 5% CO₂. Conditioned media were assayed for pro- and anti-inflammatory mediators with multiplex immunoassays or ELISA, and explant tissues for mRNA with real time PCR. Means of PTX-treated and untreated samples were compared using paired t tests and Wilcoxon-signed rank tests.ResultsPTX preferentially inhibited placental expression and production of LPS-induced pro-inflammatory cytokines including TNF-α (25461 vs. 1908 pg/ml, p < 0.001), IL-1β (2921 vs. 1067 pg/ml, p < 0.001) and IFN-γ (2190 vs 427 pg/ml, p < 0.001) with relative preservation of anti-inflammatory mediators. The suppressive effects on LPS-induced placental inflammation were independent of the timing of PTX administration in relation to LPS-induced stimulation.ConclusionOur study suggests that PTX attenuates the LPS-induced pro-inflammatory milieu in human placental explants. We speculate that PTX may have utility as a candidate anti-inflammatory agent for prophylaxis and/or treatment of human placental inflammation.     

Predictive value of intra-amniotic and serum markers for inflammatory lesions of preterm placenta

Objective

To compare the relative predictive values of amniotic fluid (AF) matrix metalloproteinase-9 (MMP-9), interleukin-6 (IL-6), and serum C-reactive protein (CRP) for histologic chorioamnionitis and intra-amniotic infection in women with preterm labor or preterm premature rupture of membranes (PROM).

Study design

This retrospective cohort study included 99 consecutive women with preterm labor or preterm PROM (21–35 weeks’ gestation) who delivered within 72 h of transabdominal amniocentesis. The AF was cultured for aerobic and anaerobic bacteria and for genital mycoplasmas and was assayed for MMP-9 and IL-6 levels. Maternal serum CRP was measured immediately after amniocentesis. The placentas were examined histologically.

Main outcome measures

histologic chorioamnionitis and intra-amniotic infection.

Results

The prevalence of histologic chorioamnionitis and a positive AF culture was 44% (44/99) and 28% (28/99), respectively. In predicting intra-amniotic infection, AF MMP-9 had a significantly higher area under the curve (AUC: 0.94 [95% CI, 0.87–0.98]) than AF IL-6 (0.87 [95% CI, 0.78–0.84]; P < 0.05) and serum CRP (0.76 [95% CI, 0.66–0.84]; P < 0.001) and a higher sensitivity and specificity than serum CRP (P < 0.01, respectively). However, in predicting histologic chorioamnionitis, there were no significant differences in AUCs among the three tests (AF MMP-9: 0.78 [95% CI, 0.68–0.85]; AF IL-6: 0.76 [95% CI, 0.66–0.84]; serum CRP: 0.76 [95% CI, 0.66–0.84]). In a sub-analysis of 71 women without intra-amniotic infection, histologic chorioamnionitis was associated with an elevated serum CRP level (P < 0.05), but not with the level of AF IL-6 or MMP-9 (P = 0.232 and P = 0.402, respectively).

Conclusions

The AF MMP-9 has a better overall diagnostic performance than the AF IL-6 and maternal serum CRP in predicting intra-amniotic infection. However, the serum CRP level obtained up to 72 h before delivery appears to be an important marker for early identification of histologic chorioamnionitis in women without intra-amniotic infection.     

The placenta dilemma

Despite the critical role the placenta plays in governing the outcome of pregnancy, a great deal remains to be learned about this transient organ. Several factors have contributed to our relative lack of knowledge. For example, most of the placenta's development, which precedes that of the embryo or fetus, occurs during the first half of pregnancy in humans. Thus, it is difficult to obtain the tissue samples that are required to study relevant time points. In addition, placental anatomy is complex; one of the most interesting parts can be obtained only by biopsy of the uterine wall. Recent analyses of these biopsies, combined with information from cell culture models, revealed the unexpected finding that placental cells that invade the uterus phenocopy many endothelial cell characteristics. This finding has several interesting implications for normal pregnancy and for pregnancy complications that could be related, either directly or indirectly, to this phenomenon, such as preeclampsia and cytomegalovirus transmission.     

The retained placenta

The incidence and importance of retained placenta (RP) varies greatly around the world. In less developed countries, it affects about 0.1% of deliveries but has up to 10% case fatality rate. In more developed countries, it is more common (about 3% of vaginal deliveries) but very rarely associated with mortality. There are three main types of retained placenta following the vagina delivery: placenta adherens (when there is failed contraction of the myometrium behind the placenta), trapped placenta (a detached placenta trapped behind a closed cervix) and partial accreta (when there is a small area of accreta preventing detachment). All can be treated by manual removal of placenta, which should be carried out at 30-60 minutes postpartum. Medical management is also an option for placenta adherens and trapped placenta. The need for manual removal can be reduced by 20% by the use of intraumbilical oxytocin (30 i.u. in 30 mL saline). A trapped placenta may respond to glyceryl trinitrate (500 mcg sublingually) or gentle, persistent, controlled cord traction.     

Correlation between symptoms of pain and peritoneal fluid inflammatory cytokine concentrations in endometriosis

Endometriosis affects 10–20% of women during reproductive age and is a common cause of infertility and pain leading to work absenteeism and reduced quality of life.The objective of this study was to investigate the association between the presence and concentration of interleukin-8 (IL-8), RANTES, osteoprotegerin (OPG), pregnancy-associated plasma protein A (PAPP-A), tumour necrosis factor-α (TNF-α), midkine and glycodelin in the peritoneal fluid (PF) and the intensity of pain reported by patients undergoing laparoscopy in our clinic. They rated their pain during menstruation, intercourse and lower abdominal using a visual analogue scale. During laparoscopy, PF was aspirated. Pain scores were correlated to the concentration of the above substances in the PF and to the stage of endometriosis. Endometriosis was histologically confirmed in 41 of 68 participating women; 27 without such evidence were considered as controls. TNF-α and glycodelin correlated positively with the level of menstrual pain. For IL-8, RANTES, OPG and PAPP-A no correlation between their PF concentration and the menstrual pain scores was observed. Patients with severe dysmenorrhoea had increased PF cytokine and marker levels; the difference was significant for TNF-α and glycodelin when compared with the other patients (no or moderate pain). TNF-α and glycodelin may thus play a role in endometriosis and the severity of menstrual pain.