Human beta-defensin-2: a natural antimicrobial peptide present in amniotic fluid participates in the host response to microbial invasion of the amniotic cavity.

OBJECTIVE: Human beta-defensin-2 (HBD-2) is a potent antimicrobial peptide that is part of the innate immune response. The purpose of this study was to determine whether HBD-2 is present in amniotic fluid and if its concentration changes with microbial invasion of the amniotic cavity (MIAC) and labor. STUDY DESIGN: Amniotic fluid was retrieved by amniocentesis from 318 patients in the following groups: (1) mid-trimester (n=75); (2) term not in labor (n=28) and in labor (n=51); (3) preterm labor and intact membranes without MIAC who delivered at term (n=36), who delivered preterm without MIAC (n=52), and preterm labor with MIAC who delivered preterm (n=25); and (4) preterm premature rupture of membranes (preterm PROM) with (n=25) and without MIAC (n=26). MIAC was defined as a positive amniotic fluid culture for microorganisms. Amniotic fluid HBD-2 concentrations were determined using a sensitive and specific ELISA. Non-parametric statistics were used for analysis. RESULTS: (1) HBD-2 was detected in all amniotic fluid samples; (2) the concentration of HBD-2 did not change with gestational age from mid-trimester to term (p=0.8); (3) intra-amniotic infection was associated with a significant increase in amniotic fluid concentrations of HBD-2 in both women with preterm labor and intact membranes, and women with preterm PROM (p<0.05 for each comparison); (4) patients with preterm labor and a negative amniotic fluid culture who delivered preterm had a higher median amniotic fluid HBD-2 concentration than those with preterm labor who delivered at term (p=0.001); and (5) among patients with preterm labor without MIAC, those who had intra-amniotic inflammation (amniotic fluid white blood cell count>100 cells per mL) had a higher median amniotic fluid concentration of HBD-2 than those without this condition (p<0.002). CONCLUSION: (1) Amniotic fluid contains HBD-2, a natural antimicrobial peptide, and this may account for some of the antimicrobial activity of amniotic fluid; (2) amniotic fluid HBD-2 concentrations are increased in women with MIAC, regardless of the membrane status (intact membranes or PROM); and (3) we propose that amniotic fluid HBD-2 is part of the innate immune system within the amniotic cavity.     

Matrix metalloproteinase 3 in parturition,premature rupture of the membranes,and microbial invasion of the amniotic cavity

OBJECTIVE: Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that are expressed in many inflammatory conditions and contribute to connective tissue breakdown. Stromelysin 1 [matrix metalloproteinase 3 (MMP-3)], a novel member of this family, is produced in the context of infection and is able to activate the latent forms of other MMPs. The purpose of this study was to determine if parturition (either term or preterm), premature rupture of the membranes (PROM), and microbial invasion of the amniotic cavity are associated with changes in amniotic fluid concentrations of MMP-3. STUDY DESIGN: A cross-sectional study was conducted, which included women who underwent transabdominal amniocentesis (n = 365) in the following categories: (1) mid-trimester with a subsequent normal pregnancy outcome (n = 84) and a subsequent fetal loss (n = 10); (2) preterm labor with intact membranes without microbial invasion of the amniotic cavity who delivered at term (n = 36), or prematurely (n = 50), and preterm labor with microbial invasion of the amniotic cavity (n = 25); (3) preterm PROM with (n = 25) and without (n = 26) microbial invasion of the amniotic cavity; (4) term with intact membranes in the absence of microbial invasion of the amniotic cavity, in labor (n = 52) and not in labor (n = 31); and (5) term with PROM in the absence of microbial invasion of the amniotic cavity and not in labor (n = 26). MMP-3 concentrations in amniotic fluid were measured by a sensitive and specific immunoassay that was validated for amniotic fluid. MMP-3 concentrations were normalized using logarithmic transformation for statistical analysis. Parametric statistics were used and a p value < 0.05 was considered statistically significant. RESULTS: (1) MMP-3 was detected in 99.5% (363/365) of amniotic fluid samples, and its concentration did not change with advancing gestational age. (2) Spontaneous parturition at term and preterm was associated with a significant increase in amniotic fluid MMP-3 concentrations (p = 0.04 and p = 0.002, respectively). (3) Spontaneous rupture of membranes in term and preterm gestations was not associated with significant changes in amniotic fluid MMP-3 concentrations. (4) Intra-amniotic infection was associated with a significant increase in amniotic fluid MMP-3 concentrations in both women with preterm labor and intact membranes (p = 0.03), and women with preterm PROM (p = 0.02). (5) Subsequent fetal loss after genetic amniocentesis was not associated with significant changes in mid-trimester concentrations of amniotic fluid MMP-3. CONCLUSIONS: (1) MMP-3 is a physiologic constituent of amniotic fluid. (2) MMP-3 may play a role in the mechanisms of human parturition and in the regulation of the host response to intrauterine infection.     

Evidence for the participation of interstitial collagenase (matrix metalloproteinase 1) in preterm premature rupture of membranes

OBJECTIVE: Rupture of membranes is thought to result from the effects of physical forces in localized areas of the membranes weakened by the degradation of structural collagens. Matrix metalloproteinases are enzymes that degrade extracellular matrix components and have been implicated in membrane rupture. The objective of this study was to determine whether spontaneous rupture of membranes is associated with a change in the amniotic fluid concentration of interstitial collagenase (matrix metalloproteinase 1 [MMP-1]), a major collagenase. STUDY DESIGN: A cross-sectional study was conducted to determine MMP-1 concentrations in amniotic fluid from 353 women in the following categories: (1) term with intact membranes not in labor and in labor, (2) preterm labor who delivered at term, (3) preterm labor who delivered preterm without microbial invasion of the amniotic cavity, (4) preterm labor who delivered preterm with microbial invasion of the amniotic cavity, (5) preterm premature rupture of membranes with and without microbial invasion of the amniotic cavity, (6) term premature rupture of membranes not in labor and in labor, and (7) mid trimester of pregnancy. Microbial invasion of the amniotic cavity was determined by an amniotic fluid culture positive for microorganisms. MMP-1 concentrations in amniotic fluid were determined by means of sensitive and specific immunoassays. RESULTS: (1) MMP-1 was detectable in 81.3% of amniotic fluid samples (287/353), and its concentrations increased with advancing gestational age (r = 0.4; P <.001). (2) Preterm premature rupture of membranes was associated with a significant increase in the median amniotic fluid concentration of MMP-1 (P =.02). (3) Women with term premature rupture of membranes had a significantly lower amniotic fluid MMP-1 concentration than those with intact membranes at term not in labor (P <.001). (4) Microbial invasion of the amniotic cavity in patients in preterm labor with intact membranes and in patients with preterm premature rupture of membranes was also associated with significant increases in the median amniotic fluid MMP-1 concentrations (P <.05 and P <.01, respectively). (5) Patients with preterm premature rupture of membranes and microbial invasion of the amniotic cavity had a significantly higher median amniotic fluid MMP-1 concentration than those with intact membranes and microbial invasion of the amniotic cavity (P =.01). (6) Neither term nor preterm parturition was associated with changes in amniotic fluid MMP-1 concentrations (P =.6 and P =.3, respectively). CONCLUSION: (1) Collagenase 1 (MMP-1) is a physiologic constituent of amniotic fluid. (2) Preterm premature rupture of membranes (in both the presence and absence of infection) was associated with an increase in the amniotic fluid MMP-1 concentrations. (3) Neither term nor preterm parturition was associated with a significant increase in the amniotic fluid concentration of MMP-1.     

Matrix Metalloproteinases-9 in Preterm and Term Human Parturition

Objective: Spontaneous rupture of the fetal membranes occurs after the commencement of labor in 90% of cases. Recent evidence indicates that the process of parturition requires not only an increase in myometrial contractility and cervical ripening, but also degradation of extracellular matrix in fetal membranes (i.e., leakage of fibronectin into cervicovaginal secretions). This study was undertaken to determine if parturition is associated with in vivo evidence of increased bioavailability of matrix metalloproteinases-9 (MMP-9) and its inhibitor, tissue inhibitor of metalloproteinases-1 (TIMP-1).

Methods: A cross-sectional study was conducted with women in the following categories: 1) midtrimester (n = 25); 2) preterm labor and intact membranes in the absence of intraamniotic infection (n = 78); 3) term not in labor (n = 25); and 4) term with intact membranes in labor (n = 25). MMP-9, and TIMP-1 were measured using sensitive and specific immunoassays.

Results: 1) Spontaneous labor at term was associated with a significant increase in MMP-9 but not in TIMP-1. 2) Women with preterm labor who delivered prematurely had significantly higher concentrations of MMP-9 but not TIMP-1 in amniotic fluid than those with preterm labor who delivered at term. 3) The concentrations of TIMP-1 decreased with advancing gestational age. In contrast, MMP-9 concentrations did not change with advancing gestational age.

Conclusions: Spontaneous human parturition is associated with specific changes in the enzymatic machinery responsible for extracellular matrix degradation.     

Evidence of in vivo differential bioavailability of the active forms of matrix metalloproteinases 9 and 2 in parturition, spontaneous rupture of membranes, and intra-amniotic infection

OBJECTIVE: Matrix metalloproteinases (MMP-9 and MMP-2) have been implicated in the digestion of fetal membranes. The purpose of this study was to determine the amniotic fluid concentrations of active forms of MMP-2 and MMP-9 and to explore the participation of these enzymes in labor (term and preterm), rupture of membranes (term and preterm), and microbial invasion of the amniotic cavity. STUDY DESIGN: A cross-sectional study was conducted with 291 women in the following categories: (1) term not in labor, (2) term in labor, (3) preterm labor and intact membranes who delivered at term, (4) preterm labor who delivered preterm, (5) preterm labor with microbial invasion of the amniotic cavity, (6) preterm premature rupture of membranes without microbial invasion of the amniotic cavity, (7) preterm premature rupture of membranes with microbial invasion of the amniotic cavity, (8) term premature rupture of membranes not in labor, and (9) mid trimester. Active forms of MMP-2 and MMP-9 were measured by a novel assay that uses a substrate developed by protein engineering. RESULTS: (1) MMP-2 and MMP-9 were detected in 88% and 96% of amniotic fluid samples, respectively (255/291 and 279/291). (2) The concentrations of active forms of MMP-2 and MMP-9 changed with advancing gestational age. (3) Spontaneous term parturition was associated with a significant increase in the median concentration of the active forms of MMP-9 (P <.005) and a significant decrease in the median concentration of the active forms of MMP-2 (P <.003). (4) Preterm labor with intact membranes leading to preterm delivery in the absence of infection was associated with a significant increase in the median concentration of the active forms of MMP-9 (P <.005) but not of the active forms of MMP-2 (P =.2). (5) Rupture of membranes (either term or preterm) was associated with a significant increase in the concentration of the active forms of MMP-9 and with a significant decrease in the concentration of the active forms of MMP-2 (P <.005 for term and P <.03 and P <.003 for preterm, respectively). (6) Microbial invasion of the amniotic cavity in women with preterm premature rupture of membranes was also associated with a significant increase in the concentration of the active forms of MMP-9 (P <.03) and a decrease in the concentration of the active forms of MMP-2 (P <.05). (7) Microbial invasion of the amniotic cavity in patients with preterm labor was associated with a significant increase in the median concentration of the active forms of MMP-9 (P <.005) but not of the active forms of MMP-2 (P =.6). CONCLUSION: Spontaneous rupture of membranes (either term or preterm), parturition (either term or preterm), and microbial invasion of the amniotic cavity were associated with significant increases in the amniotic fluid concentration of the active forms of MMP-9. In contrast, the concentration of the active forms of MMP-2 either decreased or remained the same in these conditions. Our observations provide evidence for a novel regulation of gelatinolytic activity in vivo.     

Human neutrophil collagenase (matrix metalloproteinase 8) in parturition, premature rupture of the membranes, and intrauterine infection

OBJECTIVES: The mechanisms by which microbial invasion of the amniotic cavity leads to membrane weakening and rupture are poorly understood. Recently, endogenous host enzymes have been implicated in this process. Matrix metalloproteinases are a family of potent enzymes that degrade components of the extracellular matrix. Collagen type I provides the main tensile strength of the fetal membranes. Matrix metalloproteinase 8 (MMP-8), or neutrophil collagenase, degrades interstitial collagens, acting preferentially on collagen type I. This study was undertaken (1) to determine whether MMP-8 is present in amniotic fluid and whether its concentrations are changed in preterm and term labor and membrane rupture with and without intra-amniotic infection and (2) to determine whether the amniotic fluid concentrations of MMP-8 in labor at term are different in the lower and upper uterine compartments. STUDY DESIGN: A cross-sectional study was conducted and transabdominal amniocentesis was performed in women in the following categories: (1) midtrimester (n = 25), (2) preterm labor in the presence and absence of microbial invasion of the amniotic cavity (n = 86), (3) preterm premature rupture of the membranes in the presence and absence of microbial invasion of the amniotic cavity (n = 51), (4) term patients in labor and not in labor (n = 51), and (5) term premature rupture of membranes (n = 20). Additional paired samples of amniotic fluid were retrieved by transabdominal amniocentesis (upper compartment) and transvaginal amniocentesis (lower or forebag compartment) from 14 term patients (28 samples) in spontaneous labor with intact membranes. Amniotic fluid MMP-8 concentrations were determined with a sensitive and specific immunoassay. RESULTS: MMP-8 was detected in 95.4% (249/261) of all samples. (1) Spontaneous human parturition was associated with a significant increase in amniotic fluid concentrations of MMP-8 in both term and preterm gestation. Term (no labor median, 3.3 ng/mL; range, <0.06-38.6 ng/mL; vs labor median, 16.6 ng/mL; range, 0. 33-1650 ng/mL; P <.05). Patients with preterm labor who delivered preterm (in the absence of microbial invasion of the amniotic cavity) had a significantly higher median amniotic fluid MMP-8 concentration than those with preterm labor who delivered at term (preterm labor, term delivery median, 3.1 ng/mL; range, <0.06-415.1 ng/mL; vs preterm labor, preterm delivery median, 32.5 ng/mL; range, <0.06-6006.6 ng/mL;P <.003). (2) Spontaneous rupture of membranes in preterm gestation but not in term gestation was associated with elevated amniotic fluid concentrations of MMP-8. Preterm gestation (preterm labor, intact membranes median, 3.1 ng/mL; range, <0.06-415. 1 ng/mL; vs preterm premature rupture of membranes median, 35.1 ng/mL; range, 0.71-1184.1 ng/mL; P <.05). Term gestation (intact membranes median, 3.3 ng/mL; range, 0.24-38.6 ng/mL; vs rupture of membranes median, 5.6 ng/mL; range, 0.22-19.8 ng/mL; P =.9). (3) Microbial invasion of the amniotic cavity was associated with a significant increase in amniotic fluid MMP-8 concentration in patients with preterm labor and intact membranes, as well as in patients with preterm premature rupture of membranes. Preterm labor (no microbial invasion of the amniotic cavity, preterm delivery median, 32.5 ng/mL; range, <0.06-6006.6 ng/mL; vs microbial invasion of the amniotic cavity median, 208.1 ng/mL; range, 4.2-14,600 ng/mL; P <.001). Preterm premature rupture of membranes (no microbial invasion of the amniotic cavity median, 35.1 ng/mL; range, 0.71-1184. 1 ng/mL; vs microbial invasion of the amniotic cavity median, 317.9 ng/mL; range, 2.16-14,500 ng/mL; P <.01). (4) The median amniotic fluid MMP-8 concentrations were significantly higher in fluid obtained from the forebag compartment than in that obtained from the upper compartment (median, 66.2 ng/mL; range, 7.4-170 ng/mL; vs median, 13.3 ng/mL; range, 2-170 ng/mL; respectively; P <.01). (ABSTRACT TRUNCATED)     

Fetal plasma MMP-9 concentrations are elevated in preterm premature rupture of the membranes

OBJECTIVE: The objective of this study was to determine whether the concentrations of matrix metalloproteinase-9 (MMP-9) in the fetal (fetal plasma and amniotic fluid) and maternal compartments (plasma) are different in patients presenting with preterm premature rupture of membranes (PROM) than in those with preterm labor and intact membranes. STUDY DESIGN: Fetal plasma MMP-9, interleukin-1beta (IL-1beta), IL-6, soluble tumor necrosis factor receptors 1 (sTNF-R1) and 2 (sTNF-R2) were measured in fetuses with preterm labor and intact membranes (n = 96) and preterm PROM (n = 43). The concentrations of analytes were determined with sensitive and specific immunoassays. A P value <.05 was considered significant. RESULTS: (1) The median fetal plasma MMP-9 concentration was significantly higher in fetuses with preterm PROM than in those with preterm labor (P =.035). (2) In contrast, fetal plasma IL-1beta, sTNF-R1, and sTNF-R2 were significantly higher in patients with preterm labor than in those with preterm PROM (IL-1beta, P =.01; sTNF-R1, P =.003; and sTNF-R2, P =.02). (3) The median amniotic fluid concentration of MMP-9 was higher in patients with preterm PROM than in those with preterm labor (P <.001). CONCLUSION: Fetuses with preterm PROM have increased concentrations of an enzyme (MMP-9) implicated in the mechanism of membrane rupture but lower concentrations of IL-1beta, sTNF-R1, and sTNF-R2 than fetuses with preterm labor and intact membranes. A role for the fetus in the genesis of preterm PROM deserves consideration.     

A study of the relationship between placenta growth factor and gestational age, parturition, rupture of membranes, and intrauterine infection

OBJECTIVE: Placenta growth factor is a potent angiogenic factor produced by the human placenta that has been implicated in the pathogenesis of preeclampsia and intrauterine growth restriction. Placenta growth factor belongs to the vascular endothelial growth factor family and is capable of inducing proliferation, migration, and activation of endothelial cells. The objective of this study was to determine the relationship between amniotic fluid concentration of placenta growth factor and gestational age, parturition (term and preterm), spontaneous rupture of the membranes, and intra-amniotic infection. STUDY DESIGN: Amniotic fluid samples obtained from 273 pregnant patients were assayed in the following clinical groups: midtrimester pregnancy, preterm labor who delivered at term, preterm labor without microbial invasion of the amniotic cavity who delivered preterm, preterm labor with microbial invasion of the amniotic cavity, term not in labor, term in labor, term with microbial invasion of the amniotic cavity, preterm premature rupture of membranes with and without microbial invasion of the amniotic cavity, and term with premature rupture of membranes without microbial invasion of the amniotic cavity. The placenta growth factor concentrations were determined by an immunoassay that is both sensitive and specific. RESULTS: Placenta growth factor was detectable in 96.3% (263/273) of samples. Amniotic fluid placenta growth factor concentration decreased with advancing gestational age (r = -0.42; P <.001). Amniotic fluid placenta growth factor concentrations were significantly higher in women in midtrimester pregnancy than in those at term not in labor (midtrimester pregnancy: median, 43.1 pg/mL; range, 22.9-69.8 pg/mL; vs term not in labor: median, 28.7 pg/mL; range, 16.1-82.7 pg/mL; P <.01). Neither term nor preterm parturition was associated with a change in amniotic fluid placenta growth factor concentrations. Term premature rupture of membranes was associated with a significant decrease in amniotic fluid placenta growth factor concentration (term premature rupture of membranes: median, 16.5 pg/mL; range <5.2-195.1 pg/mL; vs term intact membranes: median, 28.7 pg/mL; range, 16.1-822.7 pg/mL; P <.005). Preterm premature rupture of membranes was not associated with changes in amniotic fluid placenta growth factor concentrations. Intra-amniotic infection in preterm labor, term labor with intact membranes, and preterm premature rupture of membranes were not associated with changes in amniotic fluid placenta growth factor concentrations. CONCLUSION: Placenta growth factor is a physiologic constituent of amniotic fluid. Amniotic fluid concentrations of placenta growth factor decrease with advancing gestational age. Neither parturition nor infection affects amniotic fluid placenta growth factor concentrations.     

Evidence of participation of soluble CD14 in the host response to microbial invasion of the amniotic cavity and intra-amniotic inflammation in term and preterm gestations

Objective: Endotoxin has been implicated in the mechanism responsible for the setting of infection in preterm labor. To exert its biological effects, endotoxin binds to a circulating protein known as lipopolysaccharide binding protein (LBP) and presents endotoxin monomers to CD14, which may be a membrane-bound receptor or a soluble molecule. The endotoxin- LBP-CD14 complex interacts with Toll-like receptor 4 and other regulatory proteins leading to cellular activation and an inflammatory response. The purpose of this study was to determine whether microbial invasion of the amniotic cavity (MIAC)/intra-amniotic inflammation (both preterm and term) and parturition at term are associated with changes in the amniotic fluid and umbilical plasma soluble concentrations of CD14 (sCD14). Study design: Amniotic fluid was retrieved by amniocentesis from 88 patients in the following groups: group 1, preterm labor with intact membranes with MIAC/intra-amniotic inflammation (n = 18) and without these conditions (n = 26); group 2, term gestations not in labor without MIAC/intra-amniotic inflammation (n = 11), in labor without MIAC/intra-amniotic inflammation (n = 12) and in labor with MIAC/intra-amniotic inflammation (n = 13); and group 3, patients who underwent genetic amniocentesis at mid-trimester (n = 8). A sample of cord blood was obtained after delivery in all patients except those in group 3. sCD14 was assayed with a sensitive and specific immunoassay. Non-parametric statistics were used for analysis. A p value of < 0.05 was considered significant. Results: sCD14 was detectable in 97% (85/88) of the amniotic fluid samples. Amniotic fluid sCD14 concentrations were lower in patients at term than in the mid-trimester of pregnancy (mid-trimester: median 482 ng/ml, range 258-838 ng/ml vs. term no labor: median 7 ng/ml, range 2-274 ng/ml, p = 0.01). Among patients with preterm labor with intact membranes, the median amniotic fluid sCD14 level of patients with MIAC/intra-amniotic inflammation was higher than in patients without these conditions (median 1568 ng/ml, range 98-5887 ng/ml vs. median 645 ng/ml, range 0-3961 ng/ml, respectively; p = 0.01). Among women at term in labor, those with MIAC/intra-amniotic inflammation had a higher median amniotic fluid sCD14 concentration than those without these conditions (median 85 ng/ml, range 2-1113 ng/ml vs. median 17 ng/ml, range 0-186 ng/ml; p = 0.01). MIAC/ intra-amniotic inflammation in women with preterm labor with intact membranes was associated with a higher median umbilical venous plasma sCD14 concentration (median 744 ng/ml, range 0-3620 ng/ml vs. median 0 ng/ml, range 0-2060 ng/ml; p = 0.04). sCD14 was undetectable in plasma from umbilical cords of all neonates born to women at term. An increase in amniotic fluid concentration of sCD14 was observed in cases of intrauterine infection, not only by Gram-negative bacteria, but also Gram-positive bacteria and Ureaplasma spp. Conclusion: sCD14 is a physiological constituent of amniotic fluid, and its concentrations at term are lower than in the mid-trimester. Intrauterine infection/inflammation is associated with a higher median amniotic fluid sCD14 concentration in both preterm and term parturition. Neonates born from mothers with preterm labor with intact membranes and MIAC/intra-amniotic inflammation had a higher median concentration of sCD14 in umbilical cord plasma than those without these conditions. sCD14 concentrations are increased in the amniotic fluid and umbilical cord blood even in the absence of a microbiologically proven Gram-negative infection. CD14 appears to participate in the host response to intrauterine infection even in cases involving genital mycoplasmas.     

Matrilysin (matrix metalloproteinase 7) in parturition, premature rupture of membranes, and intrauterine infection

OBJECTIVE: Matrix metalloproteinases are enzymes capable of degrading extracellular matrix components. Matrilysin (matrix metalloproteinase 7), a novel member of this family, degrades fibronectin and proteoglycans. The objective of this study was to determine whether parturition (either term or preterm), premature rupture of the membranes, and microbial invasion of the amniotic cavity are associated with changes in the amniotic fluid concentration of matrilysin. STUDY DESIGN: A cross-sectional study was conducted with 275 women in the following categories: (1) second trimester, (2) term not in labor, (3) term in labor, (4) term with microbial invasion of the amniotic cavity, (5) preterm labor with intact membranes without microbial invasion of the amniotic cavity who delivered at term, (6) preterm labor without microbial invasion of the amniotic cavity who delivered preterm, (7) preterm labor with microbial invasion of the amniotic cavity, (8) preterm premature rupture of membranes with and without microbial invasion of the amniotic cavity, and (9) term premature rupture of membranes not in labor and without microbial invasion of the amniotic cavity. Matrilysin concentrations were measured with a sensitive specific immunoassay that was validated for amniotic fluid. RESULTS: Matrilysin was detectable in 97.4% (268/275) of the samples. The concentration of matrilysin increased with advancing gestational age (r = 0.8; P <.001). Parturition at term was not associated with a significant increase in amniotic fluid concentration of matrilysin. Preterm parturition in the absence of microbial invasion of the amniotic cavity was associated with a significant increase in amniotic fluid concentration of matrilysin (preterm labor with preterm delivery: median, 1.7 ng/mL; range, 0.45-21.6 mg/mL; vs preterm labor with term delivery: median, 1.2 ng/mL; range, 0.17-42. 1 ng/mL; P <.05). Premature rupture of membranes without microbial invasion of the amniotic cavity (either term or preterm) was not associated with a significant change in the amniotic fluid matrilysin concentration. Intra-amniotic infection was associated with a significant increase in amniotic fluid matrilysin among both patients with preterm labor and patients with preterm premature rupture of membranes (preterm labor with microbial invasion of the amniotic cavity: median, 3.2 ng/mL; range, 0.16-21.9 ng/mL; vs preterm labor and delivery without microbial invasion of the amniotic cavity: median, 1.7 ng/mL; range, 0.45-21.6 ng/mL; vs preterm labor with term delivery: median, 1.2 ng/mL; range, 0.17-42. 1 ng/mL; P <.01 for each comparison; and preterm premature rupture of membranes without microbial invasion of the amniotic cavity: median, 1.7 ng/mL; range, 0.29-13.9 ng/mL; vs preterm premature rupture of membranes with microbial invasion of the amniotic cavity: median, 3.6 ng/mL; range, 0.59-20.3 ng/mL; P <.01). CONCLUSION: Matrilysin is a physiologic constituent of amniotic fluid, and its concentration increases with advancing gestational age. Microbial invasion of the amniotic cavity in preterm gestations was associated with a significant increase in amniotic fluid concentration of matrilysin. Matrilysin therefore may play a role in the host defense mechanism.     

Lactoferrin in intrauterine infection, human parturition, and rupture of fetal membranes

OBJECTIVE: Lactoferrin is an iron-binding protein with antimicrobial properties. This study was undertaken to determine whether amniotic fluid concentrations of this protein change with gestational age, infection, labor, and rupture of membranes. STUDY DESIGN: This cross-sectional study included women who underwent transabdominal amniocentesis (n = 268) in the following groups: (1) mid trimester of pregnancy; (2) preterm labor who delivered at term, preterm labor who delivered preterm with intra-amniotic infection, and preterm labor who delivered preterm without intra-amniotic infection; (3) preterm premature rupture of membranes in the presence or absence of intra-amniotic infection; (4) term with intact membranes not in labor, in labor, and in labor with intra-amniotic infection; and (5) premature rupture of membranes at term not in labor. In addition, lactoferrin concentrations were determined in maternal plasma and cord blood of patients at term not in labor. Lactoferrin concentration was measured with an immunoassay. RESULTS: (1) Lactoferrin was detectable in 85.4% (229/268) of amniotic fluid samples, not detectable in all fluid obtained in the mid trimester, and detectable in all maternal and cord plasma samples. (2) The concentration of lactoferrin increased with advancing gestational age (r = 0.68; P <.0001). (3) Intra-amniotic infection was associated with significant increases in amniotic fluid lactoferrin concentrations in patients with preterm labor (no intra-amniotic infection median, 1641.2 ng/mL; range, <1.24-35,090.0 ng/mL; vs intra-amniotic infection median, 3833.6 ng/mL; range, 746.0-47,020.0 ng/mL; P <.001), term labor (no intra-amniotic infection median, 2085.8 ng/mL; range, 425.0-23,230.0 ng/mL; vs intra-amniotic infection median, 5627.0 ng/mL; range, <1.24-19,220.0 ng/mL; P <. 001), and preterm premature rupture of membranes (no intra-amniotic infection median, 2190 ng/mL; range, <1.24-7456.1 ng/mL; vs intra-amniotic infection median, 3449.3 ng/mL; range, <1.24-83,600. 0; P <.01). (4) Spontaneous labor at term but not preterm was associated with a significant decrease in amniotic fluid lactoferrin concentration (P <.05). (5) Spontaneous term parturition was associated with a significant increase in umbilical cord plasma lactoferrin concentration (P <.005). CONCLUSION: (1) Intra-amniotic infection was consistently associated with dramatically increased concentrations of lactoferrin in amniotic fluid. (2) Term parturition was associated with a significant increase in lactoferrin concentration in the fetal compartment (umbilical cord blood) and a decrease in the amniotic compartment. We propose that lactoferrin is part of the repertoire of host defense mechanisms against intra-amniotic infection.     

Idiopathic vaginal bleeding during pregnancy as the only clinical manifestation of intrauterine infection.

OBJECTIVE: To determine the frequency and clinical significance of microbial invasion of the amniotic cavity (MIAC) in patients with vaginal bleeding in the absence of placenta previa, preterm labor or preterm premature rupture of membranes (PROM). STUDY DESIGN: This retrospective cohort study included patients who presented with vaginal bleeding between 18 and 35 weeks, and underwent an amniocentesis shortly after admission for the assessment of the microbiologic status of the amniotic cavity and/or fetal lung maturity. Amniotic fluid was cultured for aerobic and anaerobic bacteria, as well as genital mycoplasmas. Patients presenting with preterm labor, preterm PROM, placenta previa, overt placental abruption, and an intrauterine device in situ were excluded, as well as those with local cervical bleeding. MIAC was defined as a positive amniotic fluid culture. Analysis was conducted with non-parametric statistics. RESULTS: One hundred and fourteen patients met the entry criteria. MIAC was detected in 14% of cases (16/114). Patients with vaginal bleeding and a gestational age < 28 weeks at the time of amniocentesis had a significantly higher frequency of MIAC than those with a gestational age 28 weeks [25% (13/52) vs. 4.8% (3/62), respectively; p < 0.01]. Ureaplasma urealyticum was the microorganism most frequently isolated from the amniotic fluid. Except for one case admitted at 33 weeks, all patients with MIAC had an early preterm delivery 32 weeks. Patients with vaginal bleeding and MIAC had a shorter procedure-to-delivery interval than those without MIAC [MIAC, median survival 19 days (95% CI 10-27 days) vs. no MIAC, median survival 50 days (95% CI 37-62 days); p < 0.0001]. Patients with vaginal bleeding and MIAC had a significantly lower gestational age at delivery and lower birth weight than those with vaginal bleeding and negative amniotic fluid cultures (for gestational age, median 25 weeks, range 21-33 weeks vs. median 37 weeks, range 19-42 weeks, respectively; p < 0.01, and for birth weight, median 750 grams, range 520-1820 grams vs. 2800 grams, range 520-4880 grams, respectively; p < 0.01), as well as a higher frequency of subsequent preterm PROM [81.3% (13/16) vs. 9.2% (9/98); p < 0.01]. CONCLUSIONS: MIAC was detected in 14% of patients with 'idiopathic' vaginal bleeding and was associated with subsequent preterm PROM and early preterm delivery. Vaginal bleeding may be the only clinical manifestation of MIAC, and it predisposes to adverse outcome.     

Participation of the novel cytokine interleukin 18 in the host response to intra-amniotic infection

OBJECTIVE: Interleukin 18 is a proinflammatory pleiotropic cytokine that has been implicated in the host defense against infection. This study was undertaken to determine whether interleukin 18 concentrations change in the maternal, fetal, and amniotic fluid compartments with labor (term and preterm) and microbial invasion of the amniotic cavity. STUDY DESIGN: Amniotic fluid was assayed for interleukin 18 in samples obtained from 285 patients in the following groups: (1) term not in labor (n = 22), in labor (n = 19), and with microbial invasion of the amniotic cavity (n = 16); (2) preterm labor who delivered at term (n = 38), who delivered preterm but without microbial invasion of the amniotic cavity (n = 41), and preterm labor with microbial invasion of the amniotic cavity (n = 24); (3) preterm premature rupture of membranes without microbial invasion of the amniotic cavity (n = 30) and with microbial invasion of the amniotic cavity (n = 34); (4) term premature rupture of membranes not in labor (n = 20) and term premature rupture of membranes in labor (n = 19); and (5) midtrimester (n = 22). In addition, cord and maternal plasma samples from women at term not in labor (n = 20) and in labor (n = 20) were assayed for interleukin 18. RESULTS: (1) Interleukin 18 was detectable in all amniotic fluid samples and maternal and umbilical cord blood samples. (2) Interleukin 18 concentrations increased with advancing gestational age (r = 0.47; P <.0001). (3) Microbial invasion of the amniotic cavity in either preterm or term parturition was associated with a significant increase in the amniotic fluid concentration of interleukin 18 (preterm labor without microbial invasion of the amniotic cavity: median, 14.95 pg/mL; range, 3.9-277.0 pg/mL; vs preterm labor with microbial invasion of the amniotic cavity: median, 20.75 pg/mL; range, 5.53-160.21 pg/mL; P <.02; term labor without microbial invasion of the amniotic cavity: median, 18.73 pg/mL; range, 5.09-95.44 pg/mL; vs term labor with microbial invasion of the amniotic cavity: median, 24.35 pg/mL; range, 10.07-144.42 pg/mL; P<.004). (4) Both term and preterm parturition were associated with a modest increase in amniotic fluid interleukin 18 concentrations, although this trend did not reach statistical significance. (5) Rupture of membranes at term was associated with a significant decrease in amniotic fluid interleukin 18 concentrations (intact membranes: median, 14.96 pg/mL; range, <3.89-26.07 pg/mL; vs rupture of membranes: median, 10.1 pg/mL; range, 4.29-21.44 pg/mL; P <.001). CONCLUSION: (1) Interleukin 18 is increased in cases of microbial invasion of the amniotic cavity. (2) Interleukin 18 is detectable in the amniotic, maternal, and fetal compartments. (3) We propose that this novel cytokine plays a role in the host defense against infection.     

Evidence for complement activation in the amniotic fluid of women with spontaneous preterm labor and intra-amniotic infection

Objective.?The complement system plays an important role in host defense against infection. Concentrations of complement split products or anaphylatoxins (C3a, C4a, and C5a) in biological fluids are considered to reflect complement activation. The purpose of this study was to determine if term and preterm parturition are associated with evidence of complement activation in the amniotic fluid.

Study design.?Amniotic fluid (AF) samples were collected from 270 women in the following groups: (1) normal pregnant women in midtrimester (n = 70), (2) term not in labor (n = 23), (3) term in labor (n = 48), and (4) preterm labor (PTL) (n = 129). PTL was categorized into: (a) PTL without microbial invasion of the amniotic cavity (MIAC) who delivered at term (n = 42), (b) PTL who delivered preterm without MIAC (n = 57), and (c) PTL with MIAC (n = 30). C5a, C4a, and C3a concentrations in amniotic fluid were determined by ELISA. Nonparametric tests were used for statistical analysis.

Results.?(1) The median AF C5a concentration was higher in women at term than that of those in the midtrimester (p = 0.02); (2) Spontaneous labor at term was not associated with changes in AF concentrations of anaphylatoxins C3a, C4a, and C5a (all p > 0.05); (3) Among patients with PTL who delivered preterm, those with MIAC had higher AF C4a and C5a concentrations than those without infection (p < 0.01); and (4) AF C3a, C4a, and C5a concentrations were higher in patients with PTL with MIAC than in those with PTL without MIAC who delivered at term.

Conclusion.?Patients with spontaneous preterm labor and intact membranes with microbial invasion of the amniotic cavity had higher median amniotic fluid concentration of complement split products C3a, C4a, and C5a than patients without intra-amniotic infection. These findings suggest that preterm labor in the context of infection is associated with activation of the complement system.     

Amniotic fluid heat shock protein 70 concentration in histologic chorioamnionitis,term and preterm parturition

Objective. Heat shock protein (HSP) 70, a conserved member of the stress protein family, is produced in almost all cell types in response to a wide range of stressful stimuli, and its production has a survival value. Evidence suggests that extracellular HSP70 is involved in the activation of the innate and adaptive immune response. Furthermore, increased mRNA expression of HSP70 has been observed in human fetal membranes following endotoxin stimulation. This study was conducted to determine the changes in amniotic fluid HSP70 concentrations during pregnancy, term and preterm parturition, intra-amniotic infection (IAI), and histologic chorioamnionitis.

Study design. A cross-sectional study was conducted in 376 pregnant women in the following groups: (1) women with a normal pregnancy who were classified into the following categories: (a) women in the mid-trimester (14–18 weeks) who underwent amniocentesis for genetic indications and delivered normal infants at term (n=72); (b) women at term not in labor (n = 23); and (c) those at term in labor (n = 48). (2) Women with spontaneous preterm labor and intact membranes who were subdivided into the following categories: (a) preterm labor who delivered at term without IAI (n = 42); (b) preterm labor who delivered preterm without IAI (n = 57); and (c) preterm labor and delivery with IAI (n = 30). (3) Women with preterm prelabor rupture of membranes (PROM) with (n = 50) and without (n = 54) IAI. Among patients with preterm labor with intact membranes and preterm PROM who delivered within 72 hours of amniocentesis, placenta, umbilical cord, and chorioamniotic membranes were collected and assessed for the presence or absence of acute inflammatory lesions in the extraplacental membranes (histologic chorioamnionitis) and/or umbilical cords (funisitis). HSP70 concentrations in amniotic fluid were determined using a sensitive and specific immunoassay. Non-parametric statistics were used for analysis. A p value of <0.05 was considered statistically significant.

Results. Immunoreactive HSP70 was detected in 88% (332/376) of amniotic fluid samples. The median amniotic fluid HSP70 concentration was significantly higher in women at term without labor than in those in the mid-trimester (term no labor: median 34.9 ng/mL, range 0–78.1 ng/mL vs. mid-trimester; median 6.6 ng/mL, range 0–20.8 ng/mL; p<0.001). Among patients with spontaneous preterm labor and preterm PROM, those with IAI had a significantly higher median amniotic fluid HSP70 concentration than those without IAI (preterm labor with IAI: median 82.9 ng/mL, range 0–500 ng/mL vs. preterm labor without IAI: median 41.7 ng/mL, range 0–244 ng/mL; p = 0.001; preterm PROM with IAI: median 86.5 ng/mL, range 0–428 ng/mL vs. preterm PROM without IAI: median 55.9 ng/mL, range 14.9–299.9 ng/mL; p = 0.007). There was no significant difference in the median amniotic fluid HSP70 concentration between patients with preterm labor who delivered preterm without IAI and those who delivered at term (p = 0.6). However, among patients with preterm labor without IAI, there was an inverse relationship between amniotic fluid concentration of HSP70 and the amniocentesis-to-spontaneous delivery interval (Spearman's Rho = ?0.26; p = 0.02). Patients with histologic chorioamnionitis/funisitis had a significantly higher median amniotic fluid HSP70 concentration than those without inflammation (inflammation: median 108.7 ng/mL, range 0–500 ng/mL vs. without inflammation: median 67.9 ng/mL, range 7.1–299.9 ng/mL; p = 0.02). Women at term in labor had a median amniotic fluid concentration of HSP70 significantly higher than those not in labor (term in labor: median 60.7 ng/mL, range 0–359.9 ng/mL vs. term not in labor: median 34.9 ng/mL, range 0–78.1 ng/mL; p = 0.02).

Conclusions. Intra-amniotic infection, histologic chorioamnionitis, and term parturition are associated with elevated amniotic fluid HSP70 concentrations. HSP70 plays a role in the host defense mechanism by activating the innate arm of the immune response in women with intrauterine infection. The mechanisms of preterm and term parturition in humans may involve extracellular HSP70.     

Intraamniotic infection with fusobacteria

Summary A literature search produced ten studies in which Fusobacterium was cultured from amniotic fluid in women with preterm labor and intact membranes or with preterm premature rupture of membranes (PROM). Fusobacterium was isolated in 9.9% (9/91) of positive amniotic fluid cultures in women with preterm PROM and in 28.3% (17/60) of positive amniotic fluid cultures in women presenting with preterm labor and intact membranes. Fusobacterium plays a previously unrecognized role in the pathogenesis of premature labor and delivery. Amniotic fluid culture for anaerobs, specifically Fusobacterium, is suggested for all women who present with premature labor and intact membranes and do not respond to tocolytic drugs.     

基质金属蛋白酶-8和环氧合酶-2在早产、胎膜早破时胎膜中的表达及其意义

目的 :探讨基质金属蛋白酶 8(matrixmetalloproteinase -8,MMP -8)和环氧合酶 2 (cyclooxygenase -2 ,COX- 2 )在早产、胎膜早破 (PROM)发病机制中的作用。方法 :用免疫组化法 (SP法 )检测 8例早产临产、11例早产PROM、2 0例足月PROM、10例足月临产及 12例足月未临产正常产妇 (对照组 )宫颈胎膜和宫体胎膜组织中MMP 8和COX- 2的分布和表达。结果 :(1)MMP- 8和COX -2在羊膜及绒毛膜上皮细胞和间质细胞中均可见表达 ;(2 )前 4组产妇宫颈胎膜组织中MMP 8表达的免疫组化积分分别是 5 .2 5± 0 .89、5 .73±0 .4 7、4 .0 0± 1.95、3.70± 2 .2 6 ,均高于对照组的 2 .0 8± 1.5 6 (P <0 .0 5 ) ;同时亦均高于同组产妇宫体胎膜组织MMP 8的表达 ,分别是 3.38± 1.6 9、2 .2 7± 2 .2 8、2 .2 5± 2 .0 5与 1.70± 1.6 4(P <0 .0 5 ) ;而对照组宫颈和宫体胎膜组织中MMP 8的表达差异无显著性 (P >0 .0 5 ) ;(3) 5组产妇之间宫体胎膜组织中MMP- 8的表达差异无显著性 (P >0 .0 5 ) ;(4)宫颈和宫体胎膜组织中COX -2表达的免疫组化积分 ,早产临产组为 5 .75± 0 .4 4、5 .6 3±0 .5 2 ,足月临产组为 4 .4 0± 1.4 3、3.70± 1.77,均高于对照组的 2 .92± 1.31、2 .2 5± 1.6 6 (P<0 .0 5 ) ;其中早产临产组明显增?