Faculty Bibliography

PROBLEM/OBJECTIVE:Preterm birth is frequently caused by intrauterine infection and inflammation. Recent studies have demonstrated that carbon monoxide (CO), which is produced endogenously, has potent anti-inflammatory properties. Whether or not CO can prevent infection-mediated preterm birth is unknown. METHODS:Mice were assigned to one of four groups: sham infection, sham infection + CO, infection, or infection + CO. Infections were established by intra-uterine injection of Escherichia coli on day 14 of pregnancy. Animals received daily i.p. injections of 1 mL CO-saturated lactated ringers solution (LRS) or LRS alone beginning on the morning of surgery. Gestational age at delivery and litter characteristics was noted. In second experiment, animals were sacrificed 24 hrs post-surgery and tissues were harvested for cytokine analyses. RESULTS:Escherichia coli intrauterine infection increased the number of animals delivering preterm. This effect was significantly ameliorated by CO-LRS. CO-treatment also increased litter size and weights of the surviving offspring. Cytokines in the amniotic fluid and the placenta were increased by E. coli exposure, but CO had no detectible effect on E. coli-stimulated cytokine production. No effects of CO were detected in sham-infected animals. CONCLUSION/CONCLUSIONS:Supplemental CO improves pregnancy outcome after intrauterine infection and may function at a point downstream of, or through pathways independent of, induction of proinflammatory cytokines.

Preterm birth is a leading cause of perinatal morbidity and mortality that is often associated with ascending infections from the lower genital tract. Recent studies with animal models have suggested that developmental exposure to the environmental toxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can increase the risk of preterm birth in the offspring. How TCDD may modify placental immunity to ascending infections is unclear. Therefore, we studied the effects of TCDD treatment on basal and Escherichia coli-stimulated cytokine production by placental explants. Cultures of second-trimester placentas were treated with up to 40 nM TCDD for 72 h and then stimulated with 10(7)CFU/ml E. coli for an additional 24h. Concentrations of cytokines and PGE2 were measured in conditioned medium by immunoassay. TCDD exposure increased mRNA levels of IL-1β by unstimulated cultures, but no effects on protein levels of this cytokine were detected. TNF-α production was unaffected by TCDD for unstimulated cultures, but pre-treatment with 40 nM TCDD significantly increased E. coli-stimulated TNF-α production. Both basal and bacteria-stimulated PGE2 and COX-2 gene expression were enhanced by TCDD pretreatment. In contrast, production of the anti-inflammatory cytokine, IL-10, was reduced by TCDD pretreatment for both unstimulated and E. coli-stimulated cultures. No effect of TCDD on the viability of the cultures was detected. These results suggest that TCDD exposure may shift immunity to enhance a proinflammatory phenotype at the maternal-fetal interface that could increase the risk of infection-mediated preterm birth.

PROBLEM/OBJECTIVE:Preterm birth is frequently caused by an inflammatory response to ascending infections of the reproductive tract. Carbon monoxide (CO) has potent anti-inflammatory properties at subtoxic concentrations. Whether or not CO can modulate inflammatory responses by placental tissues is unclear. METHODS:Placental explant cultures were incubated with heat-killed Escherichia coli or Ureaplasma parvum in the presence or absence of 250 ppm CO for 24 hr. Concentrations of cytokines relative viability of the cultures were quantified. RESULTS:Escherichia coli- and U. parvum-stimulated IL-1β production was significantly inhibited by CO supplementation. Escherichia coli-stimulated, but not U. parvum-stimulated, IFN-γ production was inhibited by CO. While CO inhibited PGE(2) production by unstimulated cells, no effects on bacteria-stimulated prostaglandin production were detected. CO had no effect on basal or E. coli-stimulated TNF-α production but enhanced TNF-α production by cultures stimulated with U. parvum. In addition, CO tended to improve the viability of the placental cultures. CONCLUSIONS:Low concentrations of CO tended to reduce proinflammatory cytokines and to promote the production of anti-inflammatory cytokines in a pathogen-specific manner. These properties suggest that CO may be useful for promoting a pro-pregnancy cytokine milieu by placental explants and may reduce the consequences of intrauterine infections.

BACKGROUND:Current professional guidelines, such as the Neonatal Resuscitation Program, specify significant roles for parents in decision-making at periviability. However, current federal regulations and some legal precedents indicate that resuscitation decisions should be made by the physician at the time of delivery, based on physical assessment of the infant. The enforcement of such approach would potentially increase the resuscitation of infants with poor prognoses. OBJECTIVE:To characterize the resuscitation practices of neonatologists attending deliveries of premature infants at the borderline of viability, in the context of current federal legislation. STUDY DESIGN/METHODS:A questionnaire was administered to directors of all level III neonatal intensive care units in the state of New Jersey, eliciting resuscitation decisions for hypothetical birth scenarios as well as knowledge of legal statutes. RESULTS:Resuscitation decisions for infants born at 24 weeks of gestational age were not associated with parental wishes. In contrast, parental requests were significantly associated with decisions whether to treat infants born at 22 and 23 weeks gestation. Most neonatologists believed they were knowledgeable about federal legislation, but that knowledge did not change the way they practiced. CONCLUSIONS:Our findings suggest that resuscitation of premature infants at 24 weeks gestation is the standard of care in New Jersey, a socioeconomically and ethnically diverse state that may represent broader national trends. The high compliance with parental wishes at 22 or 23 weeks is probably related to physicians' expectation of poor outcomes at these gestational ages. This approach is consistent with current recommendations of the Neonatal Resuscitation Program but may not be compatible with existing federal statutes and legal precedent.

Polybrominated diphenyl ether(s) (PBDE) are ubiquitous environmental contaminants that bind and cross the placenta but their effects on pregnancy outcome are unclear. It is possible that environmental contaminants increase the risk of inflammation-mediated pregnancy complications such as preterm birth by promoting a proinflammatory environment at the maternal-fetal interface. We hypothesized that PBDE would reduce IL-10 production and enhance the production of proinflammatory cytokines associated with preterm labor/birth by placental explants. Second-trimester placental explants were cultured in either vehicle (control) or 2 muM PBDE mixture of congers 47, 99 and 100 for 72 h. Cultures were then stimulated with 10(6) CFU/ml heat-killed Escherichia coli for a final 24 h incubation and conditioned medium was harvested for quantification of cytokines and PGE(2). COX-2 content and viability of the treated tissues were then quantified by tissue ELISA and MTT reduction activity, respectively. PBDE pre-treatment reduced E. coli-stimulated IL-10 production and significantly increased E. coli-stimulated IL-1beta secretion. PBDE exposure also increased basal and bacteria-stimulated COX-2 expression. Basal, but not bacteria-stimulated PGE(2), was also enhanced by PBDE exposure. No effect of PBDE on viability of the explants cultures was detected. In summary, pre-exposure of placental explants to congers 47, 99, and 100 enhanced the placental proinflammatory response to infection. This may increase the risk of infection-mediated preterm birth by lowering the threshold for bacteria to stimulate a proinflammatory response(s).

Preterm labor and birth continue to pose a significant challenge to physicians in the obstetrics and neonatal fields. Until specific and effective therapeutic treatments are developed to prevent preterm labor, the best means of reducing preterm birth rate is early detection and diagnosis. However, current approaches to predict preterm labor have had variable success in the clinical setting. In this review, we discuss several limitations of using biomarkers from biological samples to predict preterm labor. In addition, we propose strategies for improving our ability to predict preterm labor, as well as directing therapies that are best suited to the underlying cause of preterm labor.

OBJECTIVE: We propose a novel amniotic fluid inflammatory score from a comprehensive cytokine analysis of patients with mid-trimester short cervix. STUDY DESIGN: Amniotic fluid from singleton gestations (n = 44) with a cervical length of /=34 weeks). Mediators that reached statistical significance were included in the amniotic fluid inflammatory score. Patients were assigned 1 point for each significant mediator if their level was in the upper quartile. The amniotic fluid inflammatory score was determined, and its relationship to other clinical characteristics was examined. RESULTS: Fourteen mediators met the criteria. A score of >/=8 was predictive of delivery at <34 weeks' gestation (sensitivity, 87.0%; specificity, 100%; positive predictive value, 100%; negative predictive value, 87.5%). Twenty patients had a high inflammatory score (>/=8); 24 patients had a low score. All patients with a high inflammatory score delivered at <30 weeks' gestation. CONCLUSION: The amniotic fluid inflammatory score is related to delivery outcome and clinical characteristics.

Citation Peltier MR, Gurzenda EM, Murthy A, Chawala K, Lerner V, Kharode I, Arita Y, Rhodes A, Maari N, Moawad A, Hanna N. Can oxygen tension contribute to an abnormal placental cytokine milieu? Am J Reprod Immunol 2011; 66: 279-285 Objective The aim of this study was to determine whether culturing human placental explants under different oxygen tensions will alter expression of pro- and anti-inflammatory mediators. Methods Placental explant cultures from second-trimester, elective, terminations-of-pregnancy were incubated under 21, 5, or 1% O(2) concentrations for 24 hr in the presence or absence of IL-10. Cytokine concentrations in the conditioned medium were quantified by immunoassay. Results Culture of placental explants under 21, 5, or 1% O(2) concentrations produced hyperoxic (143 +/- 1.6 mmHg), normoxic (37 +/- 1.6 mmHg), and hypoxic (18.2 +/- 1.6 mmHg) pO(2) levels for the maternal-fetal interface in the medium. Oxygen tension had profound effects on basal placental cytokine levels as well as on IL-10-stimulated cytokine production. IL-1beta and TNF-alpha, but not IFN-gamma production, was reduced by 21% O(2) . Moreover, 21% O(2) levels increased the anti-inflammatory cytokines IL-10 and IL-13 while 1% O(2) tended to decrease the production of these cytokines. Conclusions Five percent- O(2) incubation more accurately represents in vivo pO(2) conditions at the maternal-fetal interface. Routine culture of placental explants in room air produces a superphysiologic oxygen tension that tended to increase the production of anti-inflammatory and decrease the production of pro-inflammatory cytokines. In addition, low pO(2) may reduce responsiveness of the placenta to the anti-inflammatory actions of IL-10