This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hsu, C.-D. Articles by Copel, J. A. Search for Related Content PubMed PubMed Citation Articles by Hsu, C.-D. Articles by Meaddough, E. Articles by Hong, S.-F. Articles by Aversa, K. Articles by Lu, L.-C. Articles by Copel, J. A. Social Bookmarking                   What's this?

Elevated Amniotic Fluid Nitrix Oxide Metabolites and Interleukin-6 in Intra-amniotic Infection

Erika Meaddough, MPH

Shih-Fen Hong, MPH

Kristen Aversa, BS

Li-Cheng Lu, MD

Joshua A. Copel, MD

Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut

Objective: To compare amniotic fluid nitric oxide metabolites and interleukin-6 (IL-6) concentrations in paitents with and without intra-amniotic infection.

Methods: Amniotic fluid nitric oxide metabolites, IL-6, Gram stains, glucose, leukocyte counts, leukocyte esterase activity, creatinine, pH, and specific gravity were determined in 14 patients with intra-amniotic infection and 26 patients without intra-amniotic infection. Intra-amniotic infection was defined as the presence of a positive amniotic fluid culture. The nitric oxide metabolites, nitrate and nitrite (NO_x), were measured using Greiss reagent after reduction of nitrate to nitrite with aspergillus nitrate reductase. Interleukin-6 was measured by a two-site, enzyme-linked immunosorbent assay. Amniotic fluid nitric oxide metabolites and IL-6 concentrations were normalized by amniotic fluid creatinine levels. The Mann-Whitney U test, contingency table method, and Spearman's rank correlation test were used for statistical analyses.

Results: Amniotic fluid NO_x and IL-6 levels were significantly higher in patients with intra-amniotic infection than in those without intra-amniotic infection (NO_x: median = 2.06 µmol/mg creatinine, range = 0.74-6.81 versus 1.35 µmol/mg creatinine, range = 0.99-1.60, P = .01, IL-6: median = 2.00 µg/mg creatinine, range = 0.026-4.07 versus median = 0.04 µg/mg creatinine, range = 0.004-3.210, P = .0009, respectively). Patients with intra-amniotic infection had significantly elevated leukocyte counts, leukocyte esterase activity, Gram positive stains, and significantly lower amniotic fluid glucose levels compared with those without intra-amniotic infection. There were no differences in gestational age, maternal age, parity, race, pH, or specific gravity between the two groups. Amniotic fluid NO_x was significantly correlated with IL-6 (r = .4, P = .02). Both amniotic fluid NO_x and IL-6 were also positively correlated with amniotic fluid leukocyte counts, leukocyte esterase activity and Gram stains, and negatively correlated with glucose levels.

Conclusions: Amniotic fluid NO_x and IL-6 are significantly elevated and positively correlated during intra-amniotic infection. Both increased amniotic fluid IL-6 and nitric oxide may exert cytotoxic and cytostatic effects on the target cells. We suggest that measurements of amniotic fluid NO_x and IL-6 may serve as useful clinical markers in patients with intra-amniotic infection.

Key Words: Nitric oxide • interleukin-6 • intra-amniotic infection • amniotic fluid

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?