Infections and other inflammatory conditions

Neuroimaging findings associated with the fetal inflammatory response syndrome

The fetal inflammatory response syndrome (FIRS) is a condition whereby the fetus mounts an inflammatory response to intrauterine infection/inflammation. Clinical consequences include preterm premature rupture of membranes (PPROM), spontaneous preterm delivery, neonatal sepsis, bronchopulmonary dysplasia, and brain and other organ injury. Mechanisms leading to brain injury in FIRS have been investigated in animal and human studies. We review the neuroimaging findings of brain injury in FIRS, which overlap those of hypoxic-ischemic injury, and clinical correlation is necessary for a correct diagnosis. FIRS should be considered the primary diagnosis when neuroimaging findings such as periventricular leukomalacia are identified in preterm children born as a consequence of PPROM and spontaneous preterm labor. Additionally, FIRS should be considered in term infants who do not have the most common features of HIE (e.g. a sentinel event). Systematic histopathologic examination of the placenta and umbilical cord and/or detection of characteristic inflammatory markers in such cases are needed to establish the correct diagnosis.

Adverse outcomes of measles infection during pregnancy and in the perinatal period

Measles is a major public health concern. Recently, there has been an increase of measles infections worldwide due to low vaccination coverage in certain regions that allowed for the development of measles outbreak in susceptible populations. According to the World Health Organization (WHO), there have been significant measles outbreaks in all WHO regions, and below 10% of cases were reported [1]. It is difficult to measure the impact of measles virus infection on pregnancy outcome.

Inflammatory and vascular placental lesions are associated with neonatal amplitude integrated EEG recording in early premature neonates

INTRODUCTION

Placental histologic examination can assist in revealing the mechanism leading to preterm birth. Accumulating evidence suggests an association between intrauterine pathological processes, morbidity and mortality of premature infants, and their long term outcome. Neonatal brain activity is increasingly monitored in neonatal intensive care units by amplitude integrated EEG (aEEG) and indices of background activity and sleep cycling patterns were correlated with long term outcome. We hypothesized an association between types of placental lesions and abnormal neonatal aEEG patterns.

OBJECTIVE

To determine the association between the placental lesions observed in extreme preterm deliveries, and their neonatal aEEG patterns and survival.

PATIENTS AND METHODS

This prospective cohort study included extreme premature infants, who were born ≤ 28 weeks of gestation, their placentas were available for histologic examination, and had a continues aEEG, soon after birth)n = 34). Infants and maternal clinical data were collected. aEEG data was assessed for percentage of depressed daily activity in the first 3 days of life and for sleep cycling. Associations of placental histology with clinical findings and aEEG activity were explored using parametric and non-parametric statistics.

RESULTS

Twenty two out of the 34 newborns survived to discharge. Preterm prelabor rupture of membranes (PPROM) or chorioamnionitis were associated with placental lesions consistent with fetal amniotic fluid infection (AFI) or maternal under perfusion (MUP) (P < 0.05). Lesions consistent with fetal response to AFI were associated with absence of SWC pattern during the 1st day of life. Fetal-vascular-thrombo-occlusive lesions of inflammatory type were negatively associated with depressed cerebral activity during the 1st day of life, and with aEEG cycling during the 2nd day of life (P<0.05). Placental lesions associated with MUP were associated with depressed neonatal cerebral activity during the first 3 days of life (P = 0.007).

CONCLUSIONS

Depressed neonatal aEEG patterns are associated with placental lesions consistent with maternal under perfusion, and amniotic fluid infection of fetal type, but not with fetal thrombo-oclusive vascular disease of inflammatory type. Our findings highlight the association between the intrauterine mechanisms leading to preterm parturition and subsequent depressed neonatal cerebral function early after birth, which eventually may put premature infants at risk for abnormal neurodevelopmental outcome.

CXCL10 and IL-6: Markers of two different forms of intra-amniotic inflammation in preterm labor

Problem

To determine whether amniotic fluid (AF) CXCL10 concentration is associated with histologic chronic chorioamnionitis in patients with preterm labor (PTL) and preterm prelabor rupture of the membranes (PROM).

Method of Study

This study included 168 women who had an episode of PTL or preterm PROM. AF interleukin (IL)‐6 and CXCL10 concentrations were determined by immunoassay.

Results

(i) Increased AF CXCL10 concentration was associated with chronic (OR: 4.8; 95% CI: 1.7‐14), but not acute chorioamnionitis; (ii) increased AF IL‐6 concentration was associated with acute (OR: 4.2; 95% CI: 1.3‐13.7) but not chronic chorioamnionitis; and (iii) an increase in AF CXCL10 concentration was associated with placental lesions consistent with maternal anti‐fetal rejection (OR: 3.7; 95% CI: 1.3‐10.4). (iv) All patients with elevated AF CXCL10 and IL‐6 delivered preterm.

Conclusion

Increased AF CXCL10 concentration is associated with chronic chorioamnionitis or maternal anti‐fetal rejection, whereas increased AF IL‐6 concentration is associated with acute histologic chorioamnionitis.

Histological characteristics of the fetal inflammatory response associated with neurodevelopmental impairment and death in extremely preterm infants

OBJECTIVE

To test the hypothesis that increasing severity of the fetal inflammatory response (FIR) would have a dose-dependent relationship with severe neurodevelopmental impairment or death in extremely preterm infants.

STUDY DESIGN

We report 347 infants of 23-28 weeks gestational age admitted to a tertiary neonatal intensive care unit between 2006 and 2008. The primary outcome was death or neurodevelopmental impairment at the 18- to 22-month follow-up. Exposure status was defined by increasing stage of funisitis (stage 1, phlebitis; stage 2, arteritis with or without phlebitis; stage 3, subacute necrotizing funisitis) and severity of chorionic plate vasculitis (inflammation with or without thrombosis).

RESULTS

A FIR was detected in 110 placentas (32%). The rate of severe neurodevelopmental impairment/death was higher in infants with subacute necrotizing funisitis compared with infants without placental/umbilical cord inflammation (60% vs 35%; P < .05). Among infants with stage 1 or 2 funisitis, the presence of any chorionic vasculitis was associated with a higher rate of severe neurodevelopmental impairment/death (47% vs 23%; P < .05). After adjustment for confounding factors, only subacute necrotizing funisitis (risk ratio, 1.87; 95% CI, 1.04-3.35; P = .04) and chorionic plate vasculitis with thrombosis (risk ratio, 2.21; 95% CI, 1.10-4.46; P = .03) were associated with severe neurodevelopmental impairment/death.

CONCLUSION

Severe FIR, characterized by subacute necrotizing funisitis and severe chorionic plate vasculitis with thrombosis, is associated with severe neurodevelopmental impairment/death in preterm infants.

Villitis of Unknown Etiology and Massive Chronic Intervillositis

Villitis of unknown etiology (VUE) is a common lesion affecting from 6.6% to 33.8% of third-trimester placentas. VUE needs to be distinguished from villitis of infectious etiology, most commonly cytomegalovirus and syphilis. Clinically, this lesion is associated with intrauterine growth retardation, intrauterine fetal demise, fetal neural impairment, maternal alloimmune and autoimmune disease, and maternal hypertension. It has a tendency to recur in subsequent pregnancies. Massive chronic intervillositis (MCI), also known as chronic histiocytic intervillositis, is a rare lesion that has an unclear relationship with VUE. MCI is associated with recurrent abortions.

A new, clinically oriented, unifying and simple placental classification system

OBJECTIVE

At present there is no internationally accepted, clinically easy understandable, comprehensive morphological placental classification. This hampers international benchmarking and comparisons, and clinical research.

STUDY DESIGN

Internationally published criteria on morphological placental pathology were collected, standardized and focused into a comprehensive diagnosis category system. The idea was to create a clinically relevant placental pathology scheme related to major pathological processes. A system of nine main diagnostic categories (normal placenta included) was constructed. Pathologists and obstetricians discussed the mutual understanding of the wording in the reporting. The previously published diagnostic criteria were merged, structured and standardized. Through an interobserver correlation study on 315 placentas from intrauterine deaths and 31 controls (placentas from live births) the microscopic criteria in this classification system were tested on user-friendliness and reproducibility.

RESULTS

The clinical feedback has been very positive, focusing on the understandability and usefulness in patient follow-up. The interobserver agreement in the microscopic correlation study was in general good. The differences in agreement mainly reflected the degree of preciseness of the microscopic criteria, exemplified by excellent correlation in diagnosing acute chorioamnionitis. Maternal and fetal circulatory disorders need grading criteria and studies are needed to get more insight and clinical correlations of villitis and maturation disorders.

CONCLUSION

The clinically oriented, unifying and simple placental pathology classification system may work as a platform for standardization and international benchmarking. Further research is needed to define diagnostic criteria in staging and grading of some main diagnostic categories.

Placental pathology in asphyxiated newborns meeting the criteria for therapeutic hypothermia

OBJECTIVE

We sought to describe placental findings in asphyxiated term newborns meeting therapeutic hypothermia criteria and to assess whether histopathologic correlation exists between these placental lesions and the severity of later brain injury.

STUDY DESIGN

We conducted a prospective cohort study of the placentas of asphyxiated newborns, in whom later brain injury was defined by magnetic resonance imaging.

RESULTS

A total of 23 newborns were enrolled. Eighty-seven percent of their placentas had an abnormality on the fetal side of the placenta, including umbilical cord lesions (39%), chorioamnionitis (35%) with fetal vasculitis (22%), chorionic plate meconium (30%), and fetal thrombotic vasculopathy (26%). A total of 48% displayed placental growth restriction. Chorioamnionitis with fetal vasculitis and chorionic plate meconium were significantly associated with brain injury (P = .03). Placental growth restriction appears to significantly offer protection against the development of these injuries (P = .03).

CONCLUSION

Therapeutic hypothermia may not be effective in asphyxiated newborns whose placentas show evidence of chorioamnionitis with fetal vasculitis and chorionic plate meconium.

Diagnosing placental membrane hypoxic lesions increases the sensitivity of placental examination

CONTEXT

Two relatively unknown and recently described placental membrane hypoxic lesions (laminar necrosis and microscopic chorionic pseudocysts) have never been compared with time-honored, focal (infarction), and diffuse hypoxic lesions of placental parenchyma.

OBJECTIVE

To compare the effect on placental diagnosis of the above placental membrane hypoxic lesions and chorionic disc hypoxic lesions (infarctions and global hypoxic pattern of placental injury).

DESIGN

Twenty-three clinical (maternal and fetal) and 32 gross and microscopic placental features were retrospectively compared in 4590 placentas from a placental database built during a 13-year period: 168 placentas with at least one hypoxic disc lesion (infarct or global hypoxia) and at least one membrane lesion (microscopic chorionic pseudocysts or laminar necrosis (group 1), 750 placentas with at least one hypoxic villous lesion but no membrane lesion (group 2), 480 placentas with at least one membrane lesion but no villous lesion (group 3), and 3192 placentas with no hypoxic villous or membrane lesions (group 4).

RESULTS

Several clinical and fetal conditions and placental features known to be associated with in utero hypoxia had a statistically significant correlation with the index hypoxic placental lesions, both villous and membranous. Of placentas from patients associated with clinical conditions at risk for hypoxia, 15% featured only hypoxic membrane lesions without a chorionic disc hypoxic lesion.

CONCLUSIONS

Recognizing placental membrane hypoxic lesions increases the sensitivity of placental examination in diagnosing placental hypoxia by at least 15%. The risk of in utero hypoxia is increased when microscopic chorionic pseudocysts and laminar necrosis occur in conjunction with villous hypoxic lesions.

Viral infection of the placenta leads to fetal inflammation and sensitization to bacterial products predisposing to preterm labor

Pandemics pose a more significant threat to pregnant women than to the nonpregnant population and may have a detrimental effect on the well being of the fetus. We have developed an animal model to evaluate the consequences of a viral infection characterized by lack of fetal transmission. The experiments described in this work show that viral infection of the placenta can elicit a fetal inflammatory response that, in turn, can cause organ damage and potentially downstream developmental deficiencies. Furthermore, we demonstrate that viral infection of the placenta may sensitize the pregnant mother to bacterial products and promote preterm labor. It is critical to take into consideration the fact that during pregnancy it is not only the maternal immune system responding, but also the fetal/placental unit. Our results further support the immunological role of the placenta and the fetus affecting the global response of the mother to microbial infections. This is relevant for making decisions associated with treatment and prevention during pandemics.

First-trimester cervical inflammatory milieu and subsequent early preterm birth

OBJECTIVE

Our objective was to explore the relation between the pro- and antiinflammatory cervical cytokine balance in early pregnancy and subsequent early preterm birth.

STUDY DESIGN

In this prospective cohort of 218 pregnant women who were enrolled in the first trimester, we assayed cervical concentrations of interleukin-1alpha, -1beta, -6, -4, -10, and -13. Based on these cytokines, we categorized subjects into 1 of 3 strata: high proinflammatory/low antiinflammatory, high antiinflammatory/low proinflammatory, or balanced. The primary outcome of interest was preterm birth at < 34 weeks' gestation.

RESULTS

Women in the high antiinflammatory/low proinflammatory stratum had a subsequent odds ratio for preterm birth < 34 weeks' gestation of 7.7 (95% CI, 4.9-9.1; P = .01), after adjustment for marital status, smoking, bacterial vaginosis, maternal race, and less than high school education.

CONCLUSION

Women with a relatively hyporesponsive cervical inflammatory milieu in early pregnancy are at higher risk of subsequent early spontaneous preterm birth.

Intrauterine administration of endotoxin leads to motor deficits in a rabbit model: a link between prenatal infection and cerebral palsy

OBJECTIVE

This study was undertaken to determine whether maternal intrauterine endotoxin administration leads to neurobehavioral deficits in newborn rabbits.

STUDY DESIGN

Pregnant New Zealand white rabbits were injected with 1 mL saline solution (n = 8) or 20 microg/kg of lipopolysaccharide in saline solution (n = 8) into the uterine wall on day 28/31 of gestation. On postnatal day 1, kits (saline solution [n = 30] and lipolysaccharide in saline solution [n = 18] from 4 consecutive litters) underwent neurobehavioral testing. Neonatal brains were stained for microglial cells and myelin.

RESULTS

Kits in the lipopolysaccharide in saline solution group were hypertonic and demonstrated significant impairment in posture, righting reflex, locomotion, and feeding, along with neuroinflammation indicated by activated microglia and hypomyelination in the periventricular regions. A greater mortality was noted in the lipopolysaccharide in saline solution group (16 stillbirths from 3 litters vs 3 from 1 litter).

CONCLUSION

Maternal intrauterine endotoxin administration leads to white matter injury and motor deficits in the newborn rabbit, resulting in a phenotype that resembles those found in periventricular leukomalacia and cerebral palsy.

Maternal and fetal Toll-like receptor 4 genotype and chorionic plate inflammatory lesions

OBJECTIVE

The objective of the study was to explore the relation between maternal and fetal genetic variation in Toll-like receptor 4 (TLR4) and chorionic plate inflammation

STUDY DESIGN

In this prospective observational cohort of 109 women with singleton gestations, 13 tag single nucleotide polymorphisms (SNPs) were genotyped in the TLR4 gene. The diagnosis of chorionic plate inflammation was made by a single blinded perinatal pathologist.

RESULTS

After adjustment for multiple comparisons, 1 maternal SNP (rs10759932) and 1 fetal SNP (rs1554973) in the TLR4 gene demonstrated highly significant association with chorionic plate inflammation. After adjustment for race, smoking, and bacterial vaginosis, carriage of these alleles was associated with chorionic plate inflammation (maternal rs1554973: odds ratio [OR] 5.2, 95% confidence interval, 3.2-6.4, P = .006; fetal rs10759932: OR 4.95, 95% confidence interval, 3.0-5.6, P = .005). There was no evidence of interaction between these 2 SNPs.

CONCLUSION

Maternal and fetal genetic variation in TLR4 is strongly associated with chorionic plate inflammation. This maternal and fetal genotypic effect are independent of each other as well as other environmental covariates.

Is cerebral palsy preventable?

PURPOSE OF REVIEW

To use evidence of good medical quality to update information on strategies for prevention of cerebral palsy, and on the success of these preventive efforts to date.

RECENT FINDINGS

Causes of cerebral palsy, and therefore promising approaches to prevention, differ by gestational age group and by clinical subtype. Neuroimaging and neuropathology indicate the importance of white matter disorders and of ischemic stroke in cerebral palsy; birth asphyxia, congenital malformations, placental pathology, and genetic variants also contribute to cerebral palsy risk. Multiplicity of risk factors markedly increases risk. Recent studies indicate that mild hypothermia lessens cerebral palsy risk in term infants with moderate neonatal encephalopathy, and the possibility that administration of magnesium sulphate to women in preterm labor may aid in primary prevention of cerebral palsy in very preterm infants.

SUMMARY

Past efforts to prevent cerebral palsy have not had the benefits sought, but recent results provide new hope and new challenges.

Placental pathology, a survival guide

Placental pathology continues to be an underutilized, undertaught, and inadequately handled surgical subspecialty. The requests for placental pathology are soaring, due partly to demands from obstetricians and to the litigious environment in which they practice, and to improved obstetrical care leading to pregnancies in medically challenging situations. Evaluation of the placenta requires a good understanding of the questions and issues concerning both the fetus/infant and the mother. Information from placental pathology can be critical in early neonatal care and in reproductive planning for the family, and it can provide risk assessment for neurologic outcome of the infant. A comfortable interaction among the obstetric staff, mothers, and pathologists often obviates need for legal intervention in unexpected pregnancy outcomes. Some critical pathologic features that involve maternal and fetal management are illustrated herein. A template for gross examination and a few critical histopathologic diagnostic features with clincopathologic correlation are included.

Using proteomic analysis of the human amniotic fluid to identify histologic chorioamnionitis

OBJECTIVE

To estimate the relationship between histologic chorioamnionitis and four amniotic fluid proteomic biomarkers characteristic of inflammation (defensins 2 and 1, calgranulins C and A).

METHODS

One hundred fifty-eight women with singleton pregnancies had a clinically indicated amniocentesis to rule out inflammation and infection in the context of preterm labor or preterm premature rupture of membranes. A proteomic fingerprint (Mass Restricted score) was generated from amniotic fluid using surface-enhanced laser desorption ionization time-of-flight mass spectrometry. The Mass Restricted score ranges from 0 to 4 (none to all four biomarkers present) in direct relationship with severity of intra-amniotic inflammation. Presence or absence of biomarkers was analyzed in relationship to placental pathology. Criteria for severity of histologic chorioamnionitis were 3 stages and 4 grades of inflammation of the amnion, choriodecidua and chorionic plate.

RESULTS

The prevalence of histologic chorioamnionitis was 64% (stage I 12%, stage II 16%, and stage III 37%). The Mass Restricted score significantly correlated with stages of histologic chorioamnionitis (r=0.539, P<.001), grades of choriodeciduitis (r=0.465, P<.001), and amnionitis (r=0.536, P<.001). African-American women were overrepresented in the group with severe inflammation (Mass Restricted score 3-4, P=.022). Of the four biomarkers of the Mass Restricted score, calgranulin C had the strongest relationship with presence of stage III chorioamnionitis, independent of race, amniocentesis-to-delivery interval, and gestational age.

CONCLUSION

Proteomic analysis of amniotic fluid provides an opportunity for early recognition of histologic chorioamnionitis. This methodology may in the future identify candidates for antenatal therapeutic interventions.

LEVEL OF EVIDENCE

II.