Faculty Bibliography

PROBLEM/OBJECTIVE:Placental infection induces increased levels of pro-inflammatory cytokines, which have been implicated in the pathogenesis of preterm labor. Endotoxin tolerance is a phenomenon in which exposure to a dose of endotoxin makes tissue less responsive to subsequent exposures. The objective of our study is to determine if repeated exposure to endotoxin will induce a tolerant phenotype in normal human second trimester placental tissue. METHODS OF STUDY/METHODS:Human second trimester placental explants from elective termination of pregnancy were cultured and exposed to endotoxin (LPS). After 24 hours, the media was collected for analysis, and the explants were re-exposed to LPS after adding fresh media for another 24 hours. This process was repeated for a total of 4 LPS doses. The media was collected from each day and analyzed for cytokine levels. RESULTS:The first LPS treatment stimulated the secretion of the pro-inflammatory cytokines IL-1β, TNF-α. However, their production was significantly diminished with repeated LPS doses. Production of anti-inflammatory cytokines, IL-1ra and IL-10, was also stimulated by the first LPS treatment, but secretion was more gradually and moderately decreased with repeated LPS doses compared to the pro-inflammatory cytokines. The ratios of the anti-inflammatory/pro-inflammatory mediators (IL-1ra/IL-1β and IL-10/ TNF-α) indicate a progressively more anti-inflammatory milieu with repeated LPS doses. CONCLUSIONS:Repeated LPS exposure of human second trimester placental tissues induced endotoxin tolerance. We speculate that endotoxin tolerance at the maternal-fetal interface will protect the fetus from exaggerated inflammatory responses after repeated infectious exposure.

Retroperitoneal cyst is an extremely rare complication of pregnancy. The management of this rare clinical entity is not well understood. An 18-year-old primigravid woman at 11 weeks of gestation with twins presented with complaints of severe nausea and vomiting. Abdominal magnetic resonance imaging showed a 25 x 18 x 10-cm retroperitoneal cyst reaching up to the level of xiphoid processes. No solid component or ascites was seen. She underwent ultrasound-guided percutaneous aspiration of the cyst and 2 L of fluid was removed. The cytology was negative for malignant cells. There was no recurrence of retroperitoneal cyst during the subsequent pregnancy. At 37 (0)/ (7) weeks' gestation, the patient spontaneously delivered the female fetuses in cephalic and breech presentation. There were only seven cases reported in the literature of retroperitoneal cysts during pregnancy between 1955 and 2008. Retroperitoneal cyst during pregnancy is characterized by its extremely rare incidence and its massive cyst size. Because of the difficulty in surgery due to the gravid uterus and close proximity to major organs and blood vessels, percutaneous aspiration of cyst could be an option during pregnancy.