Transmission of an uncultivated Bergeyella strain from the oral cavity to amniotic fluid in a case of preterm birth

Intrauterine infection is a recognized cause of preterm birth. The infectious organisms are believed to originate primarily from the vaginal tract and secondarily from other parts of the body. It is plausible that microbes in the oral cavity can be transmitted to the pregnant uterus. However, direct evidence supporting such a transmission is lacking. In this study, amniotic fluids of 34 pregnant women were examined by PCR using 16S and 23S rRNA universally conserved primers. Bacterial DNA was amplified from the only patient with clinical intrauterine infection and histologic necrotizing acute and chronic chorioamnionitis. One strain, Bergeyella sp. clone AF14, was detected and was 99.7% identical to a previously reported uncultivated oral Bergeyella strain, clone AK152, at the 16S rRNA level. The same strain was detected in the subgingival plaque of the patient but not in her vaginal tract. The 16S-23S rRNA sequence of clone AF14 matched exactly with the sequences amplified from the patient's subgingival plaque. These observations suggest that the Bergeyella strain identified in the patient's intrauterine infection originated from the oral cavity. This is the first direct evidence of oral-utero microbial transmission. The patient's periodontal health during pregnancy was unclear. She did not have detectable periodontal disease during postpartum examination. Bergeyella spp. had not been previously associated with preterm birth and were detected in subgingival plaque of women without clinical levels of intrauterine infection. Uncultivated species may be overlooked opportunistic pathogens in preterm birth. This study sheds new light on the implication of oral bacteria in preterm birth.

The Physiology of Fetal Membrane Rupture: Insight Gained from the Determination of Physical Properties

Premature rupture of the fetal membranes is a major cause of preterm birth and its associated infant morbidity and mortality. Recently, it has become clear that rupture of the fetal membranes, term or preterm, is not merely the result of the stretch and shear forces of uterine contractions, but is, in significant part, the consequence of a programmed weakening process. Work in the rat model has demonstrated that collagen remodeling, with activation of matrix metalloproteinases (MMPs), and apoptosis increase markedly in the amnion at end-gestation, suggesting that these processes are involved in fetal membrane weakening. We have developed fetal membrane strength testing equipment and a systematic tissue sampling methodology that has allowed us to demonstrate that term, non-labored, fetal membranes have a zone of weakness overlying the cervix, which contains biochemical markers of both collagen remodeling and apoptosis. These findings provide strong support for the concept of programmed fetal membrane weakening prior to labor. Our model has also been used to establish the physical properties of individual fetal membrane components (amnion, chorion), determine the sequence of events during the fetal membrane rupture process, and demonstrate that treatment of fetal membranes with TNF or IL-1beta, in vitro, induces weakness and the identical biochemical markers of collagen remodeling and apoptosis seen in the physiological weak zone. The ability to simultaneously correlate macroscopic physical properties with histological and biochemical fetal membrane characteristics, presents a unique perspective on the physiology of fetal membrane rupture.

Inflammatory responses in the placenta and umbilical cord

Histopathological examination of the placenta is the gold standard for evaluating antenatal inflammatory processes that might influence fetal development. Histological chorioamnionitis develops through a well-characterised stereotyped progression of maternal and fetal cellular stages that vary from patient to patient and are amenable to quantification. Increases in the intensity of these responses and their gradual transformation into a chronic phase are important variables that can adversely affect fetal physiology. Under recognised placental inflammatory lesions affecting the decidua, placental villi and fetal vessels are also potentially informative factors that should be taken into account in the studies of adverse pregnancy outcomes. This review summarises the relationships between aetiology, intensity, duration, characteristics and site of histological placental inflammation and suggests how these data may help to better understand the antenatal environment.

Induction of CTLA-4-mediated anergy contributes to persistent colonization in the murine model of gastric Helicobacter pylori infection

Helicobacter pylori infection induces gastric inflammation but the host fails to generate protective immunity. Therefore, we evaluated the immunologic mechanisms that contribute to the failure of the T cells to promote active immunity to H. pylori in the mouse model of H. pylori infection. Spleen cells from infected C57BL/6 mice underwent significantly less proliferation and cytokine production than cells from immune mice upon in vitro stimulation with H. pylori lysate. Similar results were observed when stimulating with Ag-pulsed macrophages demonstrating that hyporesponsiveness was not due to a direct effect of H. pylori virulence factors on the T cells. Ag-specific hyporesponsiveness could be reversed by the addition of high-dose IL-2 but not by removal of CD4(+)CD25(+) T cells, indicating that hyporesponsiveness was due to anergy and not due to active suppression. Cells from infected mice lacked significant suppressor activity as shown by the failure to reduce the recall response of cells from immune mice in coculture at physiologic ratios. Direct blockade of CTLA-4 using anti-CTLA-4 Fabs or indirect blockade using CTLA-4 Ig plus anti-CD28 Ab resulted in significantly increased T cell activation in vitro. The importance of CTLA-4 in establishing anergy was confirmed in an in vivo model of H. pylori infection in which mice that received anti-CTLA-4 Fabs responded to H. pylori challenge with significantly greater inflammation and significantly reduced bacterial load. These results suggest that CTLA-4 engagement induces and maintains functional inactivation of H. pylori-specific T cells during H. pylori infection resulting in a reduced immune response.

Fetal membranes from term vaginal deliveries have a zone of weakness exhibiting characteristics of apoptosis and remodeling

BACKGROUND

Recently we identified a weak zone in term, pre-labor (repeat Cesarean section) human fetal membranes (FM) overlying the cervix with biochemical characteristics suggestive of apoptosis and collagen remodeling. We suggested that this weak zone is the FM rupture initiation site. Vaginally delivered patients have a weak zone in their FM overlying the cervix; a comparable weak zone lies adjacent to the tear line in FM after spontaneous rupture (SROM).

METHODS

FM from vaginally delivered patients with artificial rupture (AROM) and SROM were collected. FM of AROM patients were marked per vagina to identify the FM zone overlying the cervix. Postpartum FM were cut, strength tested, and piece strengths were remapped to their former location on a three-dimensional model. A 10-cm diameter zone centered on the marked area (AROM), or defined weak zone (SROM) was compared with the remaining FM.

RESULTS

AROM FM exhibit a para-cervical weak zone. SROM FM exhibit a comparable zone on the tear line. The mean rupture strength within weak zones was 60% of the remaining membranes (P <.001). AROM and SROM FM weak zones both exhibit increased matrix metalloproteinase 9, increased poly (ADP-ribose) polymerase I cleavage, decreased tissue inhibitor of metalloproteinase 3 protein, and histology consistent with remodeling and apoptosis.

CONCLUSION

Vaginally delivered AROM FM contain a weak zone overlying the cervix. Vaginally delivered SROM FM contain a weak zone adjacent to the tear line that exhibits biochemical and mechanical characteristics suggestive of collagen remodeling and apoptosis comparable to those of the AR FM weak zone.

Placental pathology and cerebral palsy

Recent classification systems of cerebral palsy call for an assessment of the timing and etiology of brain injury. The placenta is an underused resource for addressing these important questions. An expert assessment of the placental pathology can provide temporally and mechanistically specific data not available from any other source. Key concepts for an understanding of the role of placental pathology are the "sentinel lesion," the high prevalence of thromboinflammatory lesions affecting large fetal placental vessels, the significance of underlying placental reserve, and the realization that placental findings can serve as markers for processes occurring in the mother or fetus.

Eradication of Helicobacter pylori and resolution of gastritis in the gastric mucosa of IL-10-deficient mice

BACKGROUND

Helicobacter pylori has been shown to induce pronounced gastric inflammation in the absence of interleukin-10 (IL-10) by 6 weeks post inoculation. The ability of IL-10(-/-) mice to eradicate H. pylori has not been demonstrated, possibly due to early sacrifice. Therefore, the long-term effect of enhanced gastritis on H. pylori colonization was determined in IL-10(-/-) mice.

METHODS

C57BL/6 and IL-10(-/-) mice were infected with H. pylori and assessed for the degree of gastritis, bacterial load, and in vitro T-cell recall response at 4 and 16 weeks of infection.

RESULTS

Infection of IL-10(-/-) mice resulted in significantly more severe gastritis than wild-type control mice and eradication of H. pylori by 4 weeks post inoculation. By 16 weeks, the level of gastritis in IL-10(-/-) was reduced to the levels observed in wild-type mice. Splenocytes from IL-10(-/-) mice were prone to produce significantly greater amounts of IFN-gamma than wild-type mice when stimulated with bacterial antigens.

CONCLUSIONS

These results indicate that the host is capable of spontaneously eradicating H. pylori from the gastric mucosa when inflammation is elevated beyond the chronic inflammation induced in wild-type mice, and that the gastritis dissipates following bacterial eradication. Additionally, these data provide support for a model of gastrointestinal immunity in which naturally occurring IL-10-producing regulatory T cells modulate the host response to gastrointestinal bacteria.

Proinflammatory cytokines found in amniotic fluid induce collagen remodeling, apoptosis, and biophysical weakening of cultured human fetal membranes

The mechanisms by which fetal membranes (FM) rupture during the birth process are unknown. We have recently reported that FM weaken, at least in part, because of a developmental process of extracellular matrix remodeling and apoptosis. We now hypothesize that cytokines that normally increase in amniotic fluid at term induce FM collagen remodeling and apoptosis with concomitant weakening. Full-thickness FM fragments were cultured with (0-100 ng/ml) or without tumor necrosis factor (TNF) or interleukin 1, beta (IL1B). Physical properties were then examined with specially adapted industrial rupture strength testing equipment. Cultured FM were also evaluated for evidence of collagen remodeling and apoptosis. Cytokine-treated FM exhibited a dose-dependent decrease in strength and work to rupture. Compared with controls, the highest TNF dose caused maximal decrease in FM rupture strength (13.2 +/- 1.2 N versus 3.8 +/- 1.5 N; P = 0.0003) and work to rupture (0.035 +/- 0.005 J versus 0.005 +/- 0.002 J; P < 0.0001). The highest IL1B dose also decreased rupture strength (12.9 +/- 3.2 versus 4.6 +/- 1.1 N; P = 0.0027) and work to rupture (0.018 +/- 0.005 J versus 0.005 +/- 0.002 J; P < 0.01). Matrix metalloproteinase 9 (MMP9) protein increased, tissue inhibitor of matrix metalloproteinase 3 (TIMP3) protein decreased, and poly (ADP-ribose) polymerase (PARP1) cleavage increased with increasing TNF or IL1B doses (all P < 0.05), suggesting collagen remodeling and apoptosis. TNF and IL1B cause significant weakening of cultured FM. Both cytokines induce biochemical markers in the FM in a manner characteristic of the weak zone of FM overlying the cervix. TNF and or IL1B may be involved in the development of the weak zone of the FM.

Placental diagnostic criteria and clinical correlation – a workshop report

Placental pathology is a valuable link explaining how underlying pregnancy risk factors result in adverse pregnancy outcome. This potentially useful information is currently underutilized due to a general lack of rigor in placental diagnosis. This lack of rigor is in large part due to a failure to appreciate the importance of the information provided and hence to demand accurate and clinically responsive reporting. This workshop reviewed the results of a recent initiative by the Perinatal Section of the Society for Pediatric Pathology to systematize and validate diagnostic schema for the description of lesions related to three important pathologic processes: amniotic fluid infection, maternal vascular underperfusion, and fetal vascular obstruction. This was followed by presentation of three studies correlating these pathologic processes with the following clinical outcomes: complications of prematurity, fetal growth restriction, and neurodisability following term delivery.

Molecular analysis of Helicobacter pylori-associated gastric inflammation in naïve versus previously immunized mice

To identify mechanisms of immunity against Helicobacter pylori, we performed microarray analysis on gastric tissue from infected mice and mice vaccinated prior to challenge. RNA from gastric tissue was used to screen over 10,000 genes. MHC antigens and GTP binding proteins were upregulated in both groups. Infected mice were characterized by expression of innate host defense markers while immune mice expressed many IFN-gamma response genes and T cell markers. Results were confirmed for several genes by RT-PCR. CD4+ spleen cells from immune mice produced significantly more IFN-gamma than from infected mice. These results support a role for T cell regulated inflammation in H. pylori immunity.

Term Human Fetal Membranes Have a Weak Zone Overlying the Lower Uterine Pole and Cervix Before Onset of Labor1

The etiology of fetal membrane (FM) rupture is unknown. A hypothesis that the FM weakens by a process of collagen remodeling and apoptosis to facilitate rupture has been proposed. Human FMs reportedly exhibit a zone of altered histology, postulated to be the FM rupture site, but concomitant FM weakness has not been demonstrated. We hypothesized that a discrete zone of FM with marked weakness, histological change, and evidence of remodeling and apoptosis, develops in late gestation in the FM overlying the cervix. FM tissue from women undergoing prelabor cesarean delivery were perioperatively marked to identify the FM overlying the cervix, cut with a procedure that facilitates remapping the rupture strength of FM pieces to their former location and orientation on a three-dimensional model, and tested for strength. A 10-cm FM zone centered at the cervical mark was compared with the remaining FM. Mean rupture strength within the cervical zone was 55% of the remaining FM. The cervical zone also exhibited increased MMP-9 protein, decreased tissue inhibitor of metalloproteinases-3 (TIMP-3) protein, and increased PARP cleavage coincident with the previously reported zone of altered histology. A discrete zone of weakness is present in term prelabor FMs overlying the cervix and has biochemical characteristics consistent with tissue remodeling and apoptosis.

Severe fetal placental vascular lesions in term infants with neurologic impairment

OBJECTIVE

This study tests the hypothesis that placental disease can identify antepartum processes that either progress into the intrapartum period or predispose to intrapartum brain injury.

STUDY DESIGN

Lesions that affect large fetal vessels were compared in the placentas of 125 neurologically impaired term infants who were the focus of clinical negligence litigation and 250 consecutive singleton deliveries of >/=36 weeks of gestation.

RESULTS

One or more of 4 severe placental fetal vascular lesions (fetal thrombotic vasculopathy, chronic villitis with obliterative fetal vasculopathy, chorioamnionitis with severe fetal vasculitis, and meconium-associated fetal vascular necrosis) were found in 51% of index cases versus 10% of the comparison group ( P <.0001). Prevalence of these lesions in the 64 infants with cerebral palsy was 52% ( P <.0001).

CONCLUSION

Severe fetal placental vascular lesions are correlated highly with neurologic impairment and cerebral palsy. Their nature, duration, and anatomic location make them strong candidates for the antepartum processes that place fetuses at risk for brain injury during the intrapartum period.

Clinical and pathological umbilical cord abnormalities in fetal thrombotic vasculopathy

Although inherited fetal coagulation disorders may lead to fetal thrombotic vasculopathy (FTV) in occasional cases, several studies have failed to show a significant association between these 2 entities. This study tests the hypothesis that vascular stasis related to chronic umbilical cord obstruction might be a contributing factor. The study population consisted of 125 neurologically impaired term infants who were the focus of clinical negligence litigation. FTV, as defined by an average of >15 villi per slide exhibiting either a complete lack of blood vessels or villous stromal karyorrhexis, was found in the placentas of 23 cases. Clinical umbilical cord entanglement (ie, true knots or cord loops around the neck or body parts at delivery) was significantly more common in cases with FTV (61% vs 24% in cases without FTV; P = 0.0009). Potentially obstructive pathological abnormalities of the umbilical cord (marginal/ membranous insertion, decreased Wharton's jelly, maximum cord diameter <8 mm, or hypercoiling) were also more frequent in this group (30% vs 9% without FTV; P = 0.0055). Overall, 16 of 23 placentas with FTV had either clinical or pathological cord abnormalities. This study, with careful documentation of cord status at delivery and on the delivered placenta, is the first to report that clinical cord entanglement and pathological cord abnormalities are significantly increased in placentas with FTV.

Placental inflammation

Placental inflammatory disorders represent a diverse and important category of pathological processes leading to fetal and neonatal morbidity and mortality. These processes can be divided into two broad subcategories, those caused by micro-organisms and those caused by host immune responses to non-replicating antigens. The mechanisms by which these inflammatory processes cause death and disability are diverse and can be separated into four distinct classes: placental damage with loss of function, induction of premature labour and subsequent preterm birth, release of inflammatory mediators leading to fetal organ damage and transplacental infection of the fetus. Each specific inflammatory process can be modulated by properties of the specific organism, the route and timing of infection and variations in the host's genetic background and immune responsiveness. All of these factors combine to produce specific patterns of placental pathology that can be used to guide treatment, predict complications and explain adverse outcome.

Fetal vascular obstructive lesions: nosology and reproducibility of placental reaction patterns

The purpose of this study was to assemble and test the reliability of a complete set of the placental reaction patterns seen with chronic fetal vascular obstruction in the hope that this might provide a standardized diagnostic framework useful for practicing pathologists. Study cases (14 with fetal vascular obstructive lesions, 6 controls) were reviewed blindly by seven pathologists after agreement on a standard set of diagnostic criteria. Majority vote served as the gold standard and 80% of the 180 diagnoses rendered (9 diagnoses each for 20 cases) were agreed upon by at least six of the seven scores. The sensitivity of individual diagnosis relative to the group consensus averaged 83% (range, 69-100%) and specificity averaged 91% (range, 86-100%). Reproducibility was measured by unweighted kappa-values and interpreted as follows: < 0.2, poor; 0.2-0.6, fair/moderate; > 0.6, substantial. Kappa values for lesions of distal villi were generally superior to those for lesions involving large fetal vessels: avascular villi (0.49), villous stromal-vascular karyorrhexis (0.58), and villitis of unknown etiology (VUE) with stem villitis and avascular villi (0.65) versus large vessel thrombi (any vessel, 0.34; chorionic plate vessel, 0.40) and intimal fibrin cushions (recent, 0.47; remote, 0.78). Reproducibility for a global impression of any villous change consistent with chronic fetal vascular obstruction was substantial (0.63), while that for a more severe subgroup was moderate (0.44). Three points are worthy of emphasis. Our system separately recognizes, but later combines, uniformly avascular villi and villous stromal-vascular karyorrhexis as manifestations of the same underlying process. We propose that this combined group of villous lesions be dichotomized with the terms fetal thrombotic vasculopathy or extensive avascular villi (and/or villous stromal-vascular karyorrhexis) being reserved for the group with 15 or more affected terminal villi per section. Scattered foci of avascular villi (and/or villous stromal-vascular karyorrhexis) could be used to describe less severe cases. Finally, we distinguish VUE with stem villitis and avascular villi (obliterative fetal vasculopathy) as a distinct process with substantial perinatal morbidity.

Placental pathology in fetal thrombophilia

The aim of this study was to test the hypothesis that placental vascular lesions of the fetal circulation are caused by fetal thrombophilic mutations. The study included 64 newborns of women with one or more of the following pregnancy complications: preeclampsia, placental abruption, and intrauterine growth restriction. The most prevalent inherited thrombophilias--factor V Leiden, factor II (prothrombin) G20210A, and homozygosity for methyltetrahydrofolate reductase C677T--were examined in maternal blood and fetal umbilical cord blood. One pathologist reviewed all of the slides for fetal vascular lesions. Associations between fetal thrombotic vasculopathy and fetal thrombophilia were tested for using Fisher's exact test; Z scores and gestational age were compared using the Student t-test. Fetal thrombophilic mutations were diagnosed in 19 of 64 newborns, 15 of whom had coexistent maternal thrombophilia. There was no statistical difference in the prevalence of thrombotic lesions of the fetal circulation between newborns with and without thrombophilia. The combination of maternal and fetal thrombophilia was also not associated with increased fetal vascular lesions. The results indicate that fetal thrombophilia alone, even in the context of maternal underperfusion, is not associated with fetal vascular lesions of the placenta, although it may represent an underlying risk factor for lesions triggered by other process(es).

Fusobacterium nucleatum induces premature and term stillbirths in pregnant mice: implication of oral bacteria in preterm birth

Fusobacterium nucleatum is a gram-negative anaerobe ubiquitous to the oral cavity. It is associated with periodontal disease. It is also associated with preterm birth and has been isolated from the amniotic fluid, placenta, and chorioamnionic membranes of women delivering prematurely. Periodontal disease is a newly recognized risk factor for preterm birth. This study examined the possible mechanism underlying the link between these two diseases. F. nucleatum strains isolated from amniotic fluids and placentas along with those isolated from orally related sources invaded both epithelial and endothelial cells. The invasive ability may enable F. nucleatum to colonize and infect the pregnant uterus. Transient bacteremia caused by periodontal infection may facilitate bacterial transmission from the oral cavity to the uterus. To test this hypothesis, we intravenously injected F. nucleatum into pregnant CF-1 mice. The injection resulted in premature delivery, stillbirths, and nonsustained live births. The bacterial infection was restricted inside the uterus, without spreading systemically. F. nucleatum was first detected in the blood vessels in murine placentas. Invasion of the endothelial cells lining the blood vessels was observed. The bacteria then crossed the endothelium, proliferated in surrounding tissues, and finally spread to the amniotic fluid. The pattern of infection paralleled that in humans. This study represents the first evidence that F. nucleatum may be transmitted hematogenously to the placenta and cause adverse pregnancy outcomes. The results strengthen the link between periodontal disease and preterm birth. Our study also indicates that invasion may be an important virulence mechanism for F. nucleatum to infect the placenta.

Maternal vascular underperfusion: nosology and reproducibility of placental reaction patterns

Placental examination can be a useful tool for specifying the etiology, prognosis, and recurrence risk of pregnancy disorders. The purpose of this study was to test the reliability of a predetermined set of placental reaction patterns seen with maternal vascular underperfusion in the hope that this might provide a useful diagnostic framework for practicing pathologists. Study cases (14 with clinical and pathologic evidence of maternal underperfusion plus 6 controls) were evaluated for the presence or absence of 11 lesions by eight perinatal pathologists. After analysis of initial results, diagnostic criteria were refined and a second, overlapping set of cases was reviewed. The collective sensitivity, specificity, and efficiency of individual assessments for the 11 lesions relative to the group consensus ranged from 74-93% (22/33 > 90%). Reproducibility was measured by unweighted kappa-values and interpreted as follows: < 0.2 poor, 0.2-0.6 fair/moderate, > 0.6 substantial. Kappa values for lesions affecting villi and the intervillous space were increased syncytial knots (any -0.42, severe -0.50), villous agglutination (0.42), increased intervillous fibrin (0.25), and distal villous hypoplasia (0.57). Individual estimates of percent involvement for syncytial knots, intervillous fibrin, and distal villous hypoplasia were correlated with placental and fetal weight for gestational age. Extent of increased intervillous fibrin showed the strongest correlation with both placental weight ( R = -0.64) and fetal weight ( R = -0.45). Kappa values for lesions affecting maternal vessels and the implantation site were acute atherosis (0.50), mural hypertrophy of membrane arterioles (0.43), muscularized basal plate arteries (0.48), increased placental site giant cells (0.54), and immature intermediate trophoblast (0.36). Correlation of maternal vessel and implantation site lesions with the clinical diagnosis of preeclampsia showed that excessive placental site giant cells and immature intermediate trophoblast were more sensitive and efficient predictors, whereas atherosis and muscularized basal plate arteries were more specific. Kappa value for a thin umbilical cord, a possible indicator of fetal volume depletion, was 0.61. Reproducibility for a global impression of maternal vascular underperfusion, taking into account all of the above lesions, was moderate (kappa 0.54) and improved after inclusion of additional pathologic and clinical data (kappa 0.68). Adoption of this clearly defined, clinically relevant, and pathologically reproducible terminology could enhance clinicopathologic correlation and provide a more objective framework for future clinical research.

Myocytes of chorionic vessels from placentas with meconium-associated vascular necrosis exhibit apoptotic markers

Meconium-associated vascular necrosis (MAVN) is a histological abnormality of human placental chorionic vessels that is associated with poor neonatal outcome. We tested the hypothesis that MAVN shows apoptosis in the walls of chorionic vessels. Archival placental specimens with MAVN (n = 5) were compared with specimens from uncomplicated pregnancies at term (n = 5) and from placentas with intense chorionic vasculitis associated with acute chorioamnionitis with (n = 5) or without (n = 5) a clinical history of meconium in the amniotic fluid. Sections from all placentas were processed by the TUNEL method, and 2 observers who were blinded to specimen diagnosis quantified the immunofluorescent TUNEL staining in both the amnion-facing and villous-facing walls of the larger chorionic vessels in each specimen. Compared with the other 3 groups, only the amnion-facing wall of chorionic vessels in MAVN showed a significantly greater number of apoptotic cells. This was verified by morphological criteria and caspase 3 staining. There were limited or no detectable TUNEL-stained cells in either the villous-facing walls of vessels in the MAVN specimens or in any of the vessels of the placentas from uncomplicated pregnancies. There was a negligible level of apoptosis in chorionic vessels of placentas with intense chorionic vasculitis, with or without meconium, despite the inflammatory response or presence of meconium. We conclude that apoptosis contributes to the pathophysiology of MAVN.

Discordancy for maternal floor infarction in dizygotic twin placentas

Maternal floor infarction (also known as massive perivillous fibrin/fibrinoid deposition) is a rare and devastating pregnancy disorder associated with prematurity, fetal growth restriction, spontaneous abortion, and long-term neurologic impairment. Recurrence in multiple pregnancies is common. Little is known regarding either the pathophysiology or the management and treatment of patients at risk for recurrence in subsequent pregnancies. Most authors have emphasized maternal risk factors believed to act in a dominant fashion irrespective of fetal genotype. We report on dizygotic twins discordant for the development of placental maternal floor infarction and fetal growth restriction. The mother was a poorly controlled class C diabetic, and the onset of disease was coincident with the clinical onset of preeclampsia. This case demonstrates that fetal genotype, or some other factor specific to an individual fetoplacental unit, can lead to the differential expression of maternal floor infarction in dizygotic twins gestating in the same intrauterine environment.

Amniotic infection syndrome: nosology and reproducibility of placental reaction patterns

Clinically responsive placental examination seeks to provide useful information regarding the etiology, prognosis, and recurrence risk of pregnancy disorders. The purpose of this study was to assemble and validate a complete set of the placental reaction patterns seen with amniotic fluid infection in the hope that this might provide a standardized diagnostic framework useful for practicing pathologists. Study cases (14 with amniotic fluid infection, 6 controls) were reviewed blindly by six pathologists after agreement on a standard set of diagnostic criteria. After analysis of initial results, criteria were refined and a second, overlapping set of cases were reviewed. Majority vote served as the gold standard. Grading and staging of maternal and fetal inflammatory responses was found to be more reproducible using a two- versus three-tiered grading system than a three- versus five-tiered staging system (overall agreement 81% vs. 71%). Sensitivity, specificity, and efficiency for individual observations ranged from 67-100% (24/30 > 90%). Reproducibility was measured by unweighted kappa values and interpreted as follows: < 0.2, poor; 0.2-0.6, fair/moderate; > 0.6, substantial. Kappa values for the 12 lesions evaluated in 20 cases by the six pathologists were: acute chorioamnionitis/maternal inflammatory response (any, 0.93; severe 0.76; advanced stage, 0.49); chronic (subacute) chorioamnionitis (0.25); acute chorioamnionitis/fetal inflammatory response (any, 0.90; severe, 0.55; advanced stage, 0.52); chorionic vessel thrombi (0.37); peripheral funisitis (0.84); acute villitis (0.90); acute intervillositis/intervillous abscesses (0.65), and decidual plasma cells (0.30). Adoption of this clearly defined, clinically relevant, and pathologically reproducible terminology could enhance clinicopathologic correlation and provide a framework for future clinical research.

Severe inflammation and reduced bacteria load in murine helicobacter infection caused by lack of phagocyte oxidase activity

The vaccine-induced immune mechanisms that protect against Helicobacter pylori infection in the mouse model have not been identified. This study investigated the contribution of reactive oxygen and nitrogen intermediates to Helicobacter pathogenesis and immunity. Mice deficient in nicotinamide-adenine dinucleotide phosphate oxidase activity (gp91(phox-/-)), nitric oxide synthase activity (NOS2(-/-)), or both (gp91(phox-/-)/NOS2(-/-)) were infected with Helicobacter organisms and evaluated for inflammation and bacteria load. Infection of all 3 transgenic strains resulted in significantly more inflammation than found in infected C57BL/6 wild-type mice. However, only gp91(phox-/-) and gp91(phox-/-)/NOS2(-/-) mice had significantly reduced numbers of infected gastric glands. Intranasal immunization of NOS2(-/-) or gp91(phox-/-)/NOS2(-/-) mice against H. pylori resulted in protective immunity comparable to that seen in C57BL/6 control mice. Therefore, reactive oxygen species may play a role in limiting the inflammatory response associated with H. pylori infection of the gastric mucosa but may also limit the host's ability to eradicate Helicobacter organisms.

Protective efficacy of anti-Helicobacter pylori immunity following systemic immunization of neonatal mice

Helicobacter pylori infection of the gastric mucosa is a significant cause of morbidity and mortality because of its etiologic role in symptomatic gastritis, peptic ulcer disease, and gastric adenocarcinoma. Infection occurs in young children; therefore, a prophylactic vaccine would have to be administered within the first year of life, a period thought to be immunologically privileged. We investigated vaccine formulations administered by different routes to confer protective anti-H. pylori immunity in neonatal mice. Neonatal mice immunized with a single dose of vaccine in complete Freund's adjuvant (CFA) generated antigen-specific gamma interferon-, interleukin-2 (IL-2)-, IL-4-, and IL-5-secreting T cells in numbers similar to those in immunized adult mice, while vaccine administered to neonates in incomplete Freund's adjuvant (IFA) induced such cells in reduced numbers compared to those in adult mice. Both IFA and CFA, however, provided partial protection from a challenge with infectious H. pylori when the vaccine was administered subcutaneously. Neonatal immunized mice also had reduced bacterial loads when immunized intraperitoneally with CFA. In all cases, protection was equivalent to that achieved when adult counterparts were immunized. These studies suggest that an efficacious vaccine might be successfully administered to very young children to prevent perinatal infection of H. pylori.

Intrauterine exposure to infection and risk of cerebral palsy in very preterm infants

OBJECTIVE

To evaluate exposure to intrauterine infection as an independent risk factor for spastic cerebral palsy (CP) among very prematurely born infants.

STUDY DESIGN

Retrospective case-control study.

METHODS

Singleton children with gestational ages less than 32 weeks and birth weights less than 1999 g who survived to age 2 years and were born from 1988 to 1994 in a level 2 or 3 hospital in California were included in the study. Cases were children with congenital spastic CP (n = 170). Controls were children randomly sampled within 250-g birth weight intervals (n = 270). Gestational age was controlled through multiple logistic models. Major analyses were controlled for preeclampsia and short time between admission and delivery.

RESULTS

Neither clinical nor histologic indicators of intrauterine infection were associated with total spastic CP or spastic diplegia in these infants. Although not predicted by prior hypothesis, we observed an approximate doubling of risk for infants of infected mothers among children born to white women, whereas no association was noted among children born to women of other races/ethnicities. White controls had lower frequency of all measured infection indicators compared with white cases and cases and controls of other races/ethnicities.

CONCLUSION

Exposure to intrauterine infection was not an independent risk factor for CP in very premature infants when gestational age and other confounders were tightly controlled.