Significance of chorioamnionitis

Interleukin-6 pathobiology in equine placental infection

PROBLEM

Ascending placentitis is the leading cause of abortion in the horse. Interleukin (IL)-6 is considered predictive of placental infection in other species, but little is understood regarding its role in the pathophysiology of ascending placentitis.

METHOD OF STUDY

Sub-acute ascending placentitis was induced via trans-cervical inoculation of S zooepidemicus, and various fluids/serum/tissues collected 8 days later. Concentrations of IL-6 were detected within fetal fluids and serum in inoculated (n = 6) and control (n = 6) mares. RNASeq was performed on the placenta (endometrium and chorioallantois) to assess transcripts relating to IL-6 pathways. IHC was performed for immunolocalization of IL-6 receptor (IL-6R) in the placenta.

RESULTS

IL-6 concentrations increased in allantoic fluid following inoculation, with a trend toward an increase in amniotic fluid. Maternal serum IL-6 was increased in inoculated animals, while no changes were noted in fetal serum. mRNA expression of IL-6-related transcripts within the chorioallantois indicates that IL-6 is activating the classical JAK/STAT pathway, thereby acting as anti-inflammatory, anti-apoptotic, and pro-survival. The IL-6R was expressed within the chorioallantois, indicating a paracrine signaling pathway of maternal IL-6 to fetal IL-6R.

CONCLUSION

IL-6 plays a crucial role in the placental response to induction of sub-acute equine ascending placentitis, and this could be noted in amniotic fluid, allantoic fluid, and maternal serum. Additionally, IL-6 is acting as anti-inflammatory in this disease, potentially altering disease progression, impeding abortion signals, and assisting with the production of a viable neonate.

Anti-annexin A2 IgM antibody in preterm infants: its association with chorioamnionitis

Intrauterine infection is associated with chorioamnionitis (CAM), which can lead to preterm delivery. We previously reported that the levels of IgM and the incidence of CAM were elevated in preterm infants with neonatal pulmonary emphysema. The pathogen and target of this IgM remain unclear. By using Western blot and amino acid sequences, we have determined one of the target proteins: annexin A2. Immunohistochemical analysis showed that annexin A2 was expressed at fetal chorion and amnion membranes. Among very low birth weight (VLBW) infants with hyper-IgM (> or = 30 mg/dL), 58.8% showed a high titer against annexin A2 (more than x 16), which accounted for about 20%-40% of the total IgM. Anti-annexin A2 IgM antibody inhibited plasmin generation. Furthermore, the median of anti-annexin A2 IgM titer from preterm infants who were delivered with high-grade (grade III) CAM was significantly higher than those from preterm infants without CAM (p = 0.011) and with low-grade CAM (grade I and II) (p = 0.010). Here, we indicate the fetal autoimmunoreactivity against the fetomaternal interface in preterm infants.

Sonographic measurement of cervical length in preterm prelabor amniorrhexis

OBJECTIVE

To determine whether sonographic measurement of cervical length in pregnancies complicated by preterm prelabor amniorrhexis helps distinguish between those women who deliver within 7 days and those who do not.

METHODS

In 101 women with singleton pregnancies presenting with preterm prelabor amniorrhexis at 24-36 (median, 32) weeks of gestation cervical length was measured by transvaginal ultrasound. Exclusion criteria were active labor defined by the presence of cervical dilatation of > or = 3 cm and iatrogenic delivery for fetal or maternal indication when not in active labor. The clinical management was determined by the attending obstetrician. The primary outcome of the study was delivery within 7 days of presentation.

RESULTS

Delivery within 7 days of presentation occurred in 58/101 (57%) pregnancies. Logistic regression analysis demonstrated that significant independent contribution in the prediction of delivery within 7 days was provided by cervical length (odds ratio (OR) = 0.91, 95% CI 0.86-0.96, P = 0.001), gestation at presentation (OR = 1.35, 95% CI 1.14-1.59, P = 0.001) and presence of contractions at presentation (OR = 3.07, 95% CI 1.05-8.92, P = 0.039) with no significant independent contribution from ethnic origin, maternal age, body mass index, parity, previous history of preterm delivery, cigarette smoking, vaginal bleeding or the administration of tocolytics, antibiotics or steroids.

CONCLUSION

In women with preterm prelabor amniorrhexis prediction of delivery within 7 days is provided by cervical length, gestation and presence of contractions at presentation.

Placental and other perinatal risk factors for chronic lung disease in very low birth weight infants

To clarify the relationship between chorioamnionitis and chronic lung disease (CLD) in very low birth weight (VLBW) infants, we performed a retrospective cohort study of all inborn patients between 1995-1997 with gestational age (GA) less than 32 wk, birth weight less than 1.5 kg, survival to 36 wk adjusted GA, and placentas submitted to pathology (n = 371). Racial distribution as defined by the mother was 40% white/60% nonwhite. Prevalence of CLD, defined as O(2) dependence at 36 wk adjusted GA, was 30%. In a preliminary analysis GA and birth weight for GA (standard deviations from the mean, Z-score), considered together, were inversely related to CLD. After adjustment for GA and Z-score, other risk factors for CLD were white race, acute respiratory distress, pulmonary air leak, patent ductus arteriosus, and septicemia. Two placental lesions were inversely related to CLD: histologic chorioamnionitis and acute atherosis (a placental indicator of preeclampsia). Following multivariate analysis, independent risk factors for CLD were GA (OR, 0.6; 95% CI = 0.5, 0.7), birthweight for GA (OR, 0.4; 95% CI = 0.3, 0.6), white race (OR, 1.9; 95% CI = 1.0, 3.3), patent ductus arteriosus (OR, 2.0; 95% CI = 1.0, 3.5), and pulmonary air leak (OR, 3.0; 95% CI = 1.3, 7.1). Acute atherosis was inversely related to CLD (OR, 0.2; 95% CI = 0.1, 0.8). Chorioamnionitis was stratified by subtype and again no association with CLD was seen in the population as a whole. Finally, chorioamnionitis of all subtypes tended to be increased in white infants and decreased in black infants with CLD. This dichotomy was not explained by differences in death rates, acute respiratory distress, intubation on d 2 of life, or total duration of assisted ventilation. We conclude that while chorioamnionitis was not a risk factor for CLD in our total population, racial differences in its relationship to CLD are worthy of further study.

Re-evaluation of chorioamnionitis and funisitis with a special reference to subacute chorioamnionitis

Our purpose is to prove that prolonged inflammation of the chorionic plate, which we have termed subacute chorioamnionitis (SCAM), is a distinctive entity and should be differentiated from acute chorioamnionitis (ACAM) because it is an excellent prognostic indicator of chronic lung disease (CLD), including Wilson-Mikity syndrome (WMS). Ninety singleton placentas with stage-3 chorioamnionitis were delivered at 23 to 32 weeks of gestation during 1993 to 1996, and the infants survived more than 28 days. There were 49 placentas with stage 3 SCAM, 33 placentas with stage 3 ACAM, and 8 placentas with subacute necrotizing funisitis (SNF) and without inflammation of the chorionic plate. Fifty-three of gestation- and birthweight-matched placentas without chorioamnionitis were selected as control. To determine the risk factors for CLD, 27 clinical and 6 histological variables were analyzed. Logistic regression analysis showed that amniotic necrosis (AN) (P =.0168) and low birthweight (P =.0341) were the major contributing risk factors for CLD. SNF was not significantly related to CLD. Patients with SCAM (AN+, SNF-) were highly susceptible to CLD. In conclusion, SCAM, especially when associated with AN, seems to be a unique prognostic indicator of CLD.

Choriodecidual inflammatory syndrome (CoDIS) is the leading, and under recognised, cause of early preterm delivery and second trimester miscarriage

Severe preterm birth (delivery before 32 completed weeks of gestation), with or without preterm premature rupture of the membranes (PPROM), remains the leading cause of perinatal mortality. It is proposed that localized inflammation of the chorion and decidua in the membranes immediately above the internal cervical os, with or without amniotic cavity infection and inflammation, is the leading, but under recognised, cause of second trimester miscarriage and severe preterm delivery. The term 'CoDIS' (choriodecidual inflammatory syndrome), may provide a better understanding of the underlying pathophysiology than currently used terminology which over emphasizes the importance of overt intra-amniotic infection as opposed to localized extra-amniotic inflammation which stimulates uterine evacuation.

Effect of reactive oxygen species on fetal lung maturation

OBJECTIVES

Fetal lung maturation in preterm infants with chorioamnionitis is known to be accelerated. However, the molecular basis of this pathological acceleration has not been elucidated. We investigated whether reactive oxygen species play a role in the acceleration of fetal lung maturation.

STUDY DESIGN

On the 16th day of gestation, xanthine (1mM) and xanthine oxidase solution (0.1-100mU/ml) were injected into the intrauterine cavity of pregnant rats. On the 19th day of gestation, we examined the expression of the mRNA of surfactant associated proteins A, B and C (sp-A, sp-B and sp-C) by reverse transcription-polymerase chain reaction.

RESULTS

sp-A, sp-B and sp-C mRNAs were observed in lung tissue from fetal rats stimulated by xanthine-xanthine oxidase in contrast to the control.

CONCLUSION

Reactive oxygen species in amniotic fluid might be an important factor in accelerated fetal lung maturation associated with chorioamnionitis in the rat experimental model.

Effects of intrauterine IL-6 and IL-8 on the expression of surfactant apoprotein mRNAs in the fetal rat lung

OBJECTIVE

The purpose of this study was to investigate the effect of interleukin-6 (IL-6) and interleukin-8 (IL-8), whose concentrations are elevated with chorioamnionitis, on the expression of surfactant apoprotein mRNAs in fetal rat lung.

STUDY DESIGN

We employed an animal model in which we were able to administer substances continuously into the cavity between the fetal membranes and endometrium using a miniosmotic pump. Lipopolysaccharide (LPS), IL-6, or IL-8 was administered to timed pregnant rats for 3 days (day 16-19), and fetal lung expression of surfactant apoprotein mRNAs for SP (surfactant apoprotein)-A, SP-B, and SP-C was evaluated by Northern blot hybridization.

RESULTS

Continuous administration of LPS increased the expression of each surfactant apoprotein mRNA, but the expression of mRNAs was not dose-dependent. On the other hand, continuous IL-6 or IL-8 administration increased the expression of each surfactant apoprotein mRNA in a dose-dependent manner.

CONCLUSION

Fetal lung maturation may be promoted by either IL-6 or IL-8 produced in response to chorioamnionitis.

Prophylaxis against early adrenal insufficiency to prevent chronic lung disease in premature infants

BACKGROUND. Many extremely low birth weight infants (<1000 g) show biochemical evidence of adrenal insufficiency in the first week of life, correlating with subsequent development of chronic lung disease (CLD).

METHODS

We conducted a randomized, double-masked, placebo-controlled pilot study to test whether early treatment with low-dose hydrocortisone for 12 days (1 mg/kg/day for 9 days followed by.5 mg/kg/day for 3 days), begun before 48 hours of life, would increase the likelihood of survival without CLD.

RESULTS

Forty patients were enrolled at two centers. Birth weight and gestation were similar for treatment and placebo groups: 732 +/- 135 g versus 770 +/- 135 g and 25.2 +/- 1.3 weeks versus 25.4 +/- 1.5 weeks. More infants treated with hydrocortisone achieved study success, defined as survival without supplemental oxygen at 36 weeks' postconception (12/20 [60%] vs 7/20 [35%]). Lower birth weight, histologic chorioamnionitis, and preeclampsia were significant risk factors, whereas study center, prenatal steroids, sex, and ethnicity were not significant. Hydrocortisone treatment decreased days on >40% oxygen, days on >25% oxygen, days on ventilator, and oxygen at discharge. Among infants exposed to chorioamnionitis, hydrocortisone treatment also was associated with increased enteral intake during the first month of life and with increased weight at 36 weeks' postconception. Five treated infants and 6 placebo infants developed sepsis; 3 in each group died.

CONCLUSIONS

First, early treatment with low-dose hydrocortisone in this population of extremely low birth weight infants increased the likelihood of survival without CLD. Second, the benefit was particularly apparent in infants with chorioamnionitis. Third, a larger multicenter trial is needed to verify the primary outcome and to better evaluate risks and benefits.

Differences among acute, subacute, and chronic chorioamnionitis based on levels of inflammation-associated proteins in cord blood

The serum concentration of inflammation-associated proteins and several complement components in the cord blood of 215 newborns with and without chorioamnionitis (CAM), who were delivered between 17 and 42 weeks of gestation, were measured. We investigated the relationship of levels of serum proteins to acute, subacute, and chronic CAM, and to subacute necrotizing funisitis (SNF). Complement components C3d, C3, and C4 levels increased in subacute CAM (P = 0. 0002, P = 0.0007, P = 0.0029, respectively), whereas factor B increased in each type of CAM (P = 0.0001, P = 0.0009, P = 0.0004, respectively). Among the immunoglobulins, IgG levels were unrelated to the presence or type of CAM, IgM levels increased in subacute CAM (P < 0.0001), and IgA levels increased in chronic CAM (P < 0.0001). Among the acute phase reactants (APR), haptoglobin and C-reactive protein (CRP) levels increased in acute (P < 0.0001, P = 0.0022, respectively) and chronic CAM (P = 0.0035, P = 0.0345, respectively), whereas orosomucoid levels increased in chronic CAM (P = 0.0003). IL-6 levels increased in acute (P = 0.0011) and subacute (P = 0. 0475) CAM. C3d (P = 0.0063), C3 (P = 0.0289), C4 (P = 0.0491), and IgM (P < 0.0001) levels were increased in SNF. These findings suggest that the histologic distinction of acute, subacute, and chronic CAM is a useful indicator of the inflammatory mediator status of the infants. The infants with SNF may have ended their initial active inflammatory states, but they still have subacute immune activation.

Chorioamnionitis, cortisol, and acute lung disease in very low birth weight infants

OBJECTIVE

To explore the relationship between chorioamnionitis, postnatal cortisol concentrations, and acute respiratory distress in very low birth weight infants.

METHODS

Appropriate for gestational age infants weighing between 501 to 1500 g at birth were enrolled into this prospective, observational study, and data regarding respiratory distress on the first day of life were recorded. Serum cortisol concentrations were measured on (a) day 2, (b) day 3 or 4, and (c) day 5, 6, or 7 of life. On day (b) or (c), 3.5 microg/kg of cosyntropin (an adrenocorticotrophic hormone analog) was given, and a repeat specimen was drawn 30 minutes later. Chorioamnionitis was diagnosed by placental examination by one author (R.L.N.).

RESULTS

Forty-two infants exposed to chorioamnionitis and 37 infants not exposed were enrolled. Chorioamnionitis correlated inversely with gestational age, and was associated with decreased measures of acute respiratory support (exogenous surfactant, fraction of inspired oxygen, and ventilator support at 12 and 24 hours). Infants with chorioamnionitis had higher cortisol concentrations, both basal and stimulated. Gestational age was not significantly related to basal cortisol, but did correlate positively with stimulated values. Cortisol values from the 16 infants exposed to prenatal glucocorticoid therapy were excluded from these analyses.

CONCLUSIONS

These results provide evidence that prenatal inflammation leads to adrenal stimulation, resulting in increased cortisol secretion and accelerated lung maturation. The enhanced response to cosyntropin stimulation seen in these infants may reflect an increased adrenal capacity to respond to postnatal stressors. Because of the apparent magnitude of the effect of chorioamnionitis on cortisol measures, this factor should be included in future investigations of adrenal function in very low birth weight newborns.

Augmentation of fetal granulopoiesis with chorioamnionitis during the second trimester of gestation

Chorioamnionitis is a major hazard to pregnancy in the second trimester. It affects the fetomaternal unit, causing febrile illness in the mother. The fetus eventually is expelled because uterine contractions can no longer be suppressed after a certain stage of the disease. To determine the effects of chorioamnionitis on the fetus we examined fetal hematopoiesis, which is, for the most part, located extramedullarily during the second trimester of gestation. The study was performed morphometrically on sections of fetal tissues; the results are given as an increase of cells per square millimeter. In chorioamnionitis the fetuses (n = 18) showed increased granulopoiesis in the parenchyma of the liver (x12), in the spleen (x 5), in the portal triads of the liver (x3), and in the bone marrow (x1.35). Erythropoiesis and total hematopoiesis were reduced in all compartments. Inflammatory disease in the mother other than chorioamnionitis did not alter fetal hematopoiesis (n = 13). Under normal conditions fetal liver granulopoiesis is at a very low level within the sinusoids, but an early and substantial increase can be seen most easily in this location during infection; chorioamnionitis can thus be diagnosed from the fetal liver alone. Alterations in fetal hematopoiesis might be caused by cytokines generated at the fetomaternal interface during chorioamnionitis.