Myelopoiesis in the Liver of Stillborns With Evidence of Intrauterine Infection

Cytological, histochemical, and ultrastructural study of human foetal liver of various gestation with future implications in segmental resection: an anatomical perspective

The liver is the largest gland of the gastrointestinal tract having both exocrine and endocrine functions. Developmentally it arises as a ventral outgrowth from the gut endoderm during 3rd week of intrauterine life. The foetal liver is very important because of its synthetic and hemopoietic potential. The present work aimed to see the detailed histogenesis and development of the foetal liver by cytological, immunohistochemical and ultrastructural study. The liver tissue of nine aborted foetuses of various gestational age were studied. For cytology: special stains like Masson trichrome, periodic acid Schiff and reticulin were used, immunohistochemical staining was performed with triple antibodies (c-myc, Ki-67 and Ber-H2), and for ultrastructure: aluminium mounted specimens were coated with gold and argon gas and observed under scanning electron microscopy (EM). Cytology and immunohistochemistry showed the development of duct patterns and hemopoietic patterns in all stages of fetogenesis. The ductal plate was marked by the layer of dark brown staining cells at the edge of two portal tracts. The haemopoietic cells with sinusoids and aggregation of hepatocytes were observed in the early weeks of gestation. EM showed tree-like branching of a portal canal depicting hepatic segmentation of foetal liver. The organizational changes in lobular pattern, duct pattern, and microstructure of liver during fetogenesis are very crucial to achieve the adult morphology in feature. Histogenesis of the foetal liver follows a multistep process depending upon the gestational age, any deviation from normalcy may lead to structural and functional abnormality later in life.

The fetal inflammatory response syndrome: the origins of a concept, pathophysiology, diagnosis, and obstetrical implications

The fetus can deploy a local or systemic inflammatory response when exposed to microorganisms or, alternatively, to non-infection-related stimuli (e.g., danger signals or alarmins). The term "Fetal Inflammatory Response Syndrome" (FIRS) was coined to describe a condition characterized by evidence of a systemic inflammatory response, frequently a result of the activation of the innate limb of the immune response. FIRS can be diagnosed by an increased concentration of umbilical cord plasma or serum acute phase reactants such as C-reactive protein or cytokines (e.g., interleukin-6). Pathologic evidence of a systemic fetal inflammatory response indicates the presence of funisitis or chorionic vasculitis. FIRS was first described in patients at risk for intraamniotic infection who presented preterm labor with intact membranes or preterm prelabor rupture of the membranes. However, FIRS can also be observed in patients with sterile intra-amniotic inflammation, alloimmunization (e.g., Rh disease), and active autoimmune disorders. Neonates born with FIRS have a higher rate of complications, such as early-onset neonatal sepsis, intraventricular hemorrhage, periventricular leukomalacia, and death, than those born without FIRS. Survivors are at risk for long-term sequelae that may include bronchopulmonary dysplasia, neurodevelopmental disorders, such as cerebral palsy, retinopathy of prematurity, and sensorineuronal hearing loss. Experimental FIRS can be induced by intra-amniotic administration of bacteria, microbial products (such as endotoxin), or inflammatory cytokines (such as interleukin-1), and animal models have provided important insights about the mechanisms responsible for multiple organ involvement and dysfunction. A systemic fetal inflammatory response is thought to be adaptive, but, on occasion, may become dysregulated whereby a fetal cytokine storm ensues and can lead to multiple organ dysfunction and even fetal death if delivery does not occur ("rescued by birth"). Thus, the onset of preterm labor in this context can be considered to have survival value. The evidence so far suggests that FIRS may compound the effects of immaturity and neonatal inflammation, thus increasing the risk of neonatal complications and long-term morbidity. Modulation of a dysregulated fetal inflammatory response by the administration of antimicrobial agents, anti-inflammatory agents, or cell-based therapy holds promise to reduce infant morbidity and mortality.

Association of novel markers of liver disease with neonatal liver disease in premature baboons, Papio sp

Parenteral Nutrition (PN) Associated Liver Disease (PNALD) affects up to 60% of neonates; however, techniques for diagnosing and monitoring disease progression remain limited. The neonatal baboon model may provide a unique opportunity to identify serologic markers associated with this disease. The purpose of this study was to investigate if Hyaluronic Acid (HA), TIMP metallopeptidase inhibitor 1 (TIMP1), Amino-terminal Propeptide of Type-III Collagen (PIIINP) and Enhanced Liver Fibrosis (ELF) score associate with histological liver disease in neonatal baboons exposed to PN. Preterm baboons delivered via c-section at 67% gestation received PN for 14 days with or without Intralipid (PRT+IL, PRT-IL, respectively) or were sacrificed after birth (PRTCTR). Term baboons were sacrificed after birth (TERMCTR) or survived 14 days (TERM+14d). Serum HA, TIMP1, and PIIINP concentrations were measured by ELISA. A blinded pathologist assigned liver histological scores following necropsy. HA increased 9.1-fold, TIMP1 increased 2.2-fold, and ELF score increased 1.4-fold in PRT-IL compared to PRTCTR. ALT, AST, and GGT were within normal limits and did not vary between groups. A trend towards increased fibrosis was found in PRT-IL baboons. Microvesicular hepatocyte steatosis and Kupffer cell hypertrophy were elevated in PRT-IL vs PRTCTR. HA and TIMP1 were significantly elevated in preterm baboons with early histological findings of liver disease evidenced by hepatic steatosis, Kupffer cell hypertrophy and a trend towards fibrosis whereas traditional markers of liver disease remained normal. These novel markers could potentially be utilized for monitoring early hepatic injury in neonates.

A perfect storm: fetal inflammation and the developing immune system

Histologic chorioamnionitis is an inflammatory disorder of the placenta that commonly precedes preterm delivery. Preterm birth related to chorioamnionitis and fetal inflammation has been associated with a risk for serious inflammatory complications in infancy. In addition, preterm infants exposed to chorioamnionitis may be more susceptible to infection in the neonatal intensive care unit and possibly later in life. A significant body of work has established an association between chorioamnionitis and inflammatory processes. However, the potential consequences of this inflammation on postnatal immunity are less understood. In this review, we will discuss current knowledge regarding the effects of fetal exposure to inflammation on postnatal immune responses.

The relationship among the progression of inflammation in umbilical cord, fetal inflammatory response, early-onset neonatal sepsis, and chorioamnionitis

OBJECTIVES

No information exists about whether fetal inflammatory-response(FIR), early-onset neonatal sepsis(EONS) and chorioamnionitis(an advanced-stage of maternal inflammatory-response in extraplacental membranes) continuously increase according to the progression of inflammation in umbilical-cord(UC). The objective of current-study is to examine this-issue.

METHODS

Study-population included 239singleton pregnant-women(gestational-age[GA] at delivery: 21.6~36weeks) who had inflammation in extraplacental membranes or chorionic plate (CP) and either preterm-labor or preterm-PROM. We examined FIR, and the frequency of fetal inflammatory-responses syndrome(FIRS), proven-EONS, suspected-EONS and chorioamnionitis according to the progression of inflammation in UC. The progression of inflammation in UC was divided with a slight-modification from previously reported-criteria as follows: stage0, inflammation-free UC; stage-1: umbilical phlebitis only; stage-2: involvement of at least one UA and either the other UA or UV without extension into WJ; stage-3: the extension of inflammation into WJ. FIR was gauged by umbilical-cord-plasma(UCP) CRP concentration(ng/ml) at birth, and FIRS was defined as an elevated UCP CRP concentration at birth(≥200ng/ml).

RESULTS

Stage-0, stage-1, stage-2 and stage-3 of inflammation in UC were present in 48.1%, 15.5%, 6.7%, and 29.7% of cases. FIR continuously increased according to the progression of inflammation in UC(Kruskal-Wallis test,P<0.001; Spearman-rank-correlation test,P<0.000001,r = 0.546). Moreover, there was a significant and stepwise increase in the frequency of FIRS, proven-EONS, suspected-EONS and chorioamnionitis according to the progression of inflammation in UC(each for P<0.000005 in both chi-square test and linear-by-linear-association). Multiple logistic-regression analysis demonstrated that the more advanced-stage in the progression of inflammation in UC(i.e., stage-1 vs. stage-2 vs. stage-3), the better predictor of suspected-EONS (Odds-ratio[OR]3.358, 95%confidence-interval[CI]:1.020-11.057 vs. OR5.147, 95%CI:1.189-22.275 vs. OR11.040, 95%CI:4.118-29.592) and chorioamnionitis(OR6.593, 95%CI:2.717-15.999 vs. OR16.508, 95%CI:3.916-69.596 vs. OR20.167, 95%CI:8.629-47.137).

CONCLUSION

FIR, EONS and chorioamnionitis continuously increase according to the progression of inflammation in UC among preterm-gestations with inflammation in extraplacental membranes or CP. This finding may suggest that funisitis(inflammation in UC) is both qualitatively and quantitatively histologic-counterpart of FIRS, and a surrogate-marker for chorioamnionitis.

Preterm labor and preterm premature rupture of membranes have a different pattern in the involved compartments of acute histologoic chorioamnionitis and/or funisitis: Patho-physiologic implication related to different clinical manifestations

It is unknown whether histo-topographic findings about the involved compartments (i.e., choriodecidua, amnion, chorionic-plate) of acute-histologic chorioamnionitis (acute-HCA) and/or funisitis according to the presence or absence of intra-amniotic inflammation (IAI) and/or fetal inflammatory response syndrome (FIRS) are different between preterm labor and intact membranes (PTL) and preterm premature rupture of membranes (preterm-PROM). The involved compartments of acute-HCA and/or funisitis were examined in 161 singleton preterm-births (<34 weeks) due to PTL (n = 88) and preterm-PROM (n = 73). The study-population was divided into IAI(-)/FIRS(-), IAI(+)/FIRS(-), and IAI(+)/FIRS(+) groups according to the presence or absence of IAI (amniotic-fluid MMP-8 ≥ 23 ng/ml) and/or FIRS (umbilical-cord plasma CRP ≥ 200 ng/ml). Histological inflammation was not detected in any-compartment except choriodecidua in IAI(-)/FIRS(-) group with PTL while inflammation appeared in all-compartment0s (choriodeciduitis-46.2 %; amnionitis-23.1 %; funisitis-30.8 %; chorionic-plate inflammation-7.7 %) in IAI(-)/FIRS(-) group with preterm-PROM. IAI(+)/FIRS(-) group had a significantly higher frequency of inflammation in each-compartment than IAI(-)/FIRS(-) group in PTL (each-for P < 0.01), but not preterm-PROM (each-for P > 0.1). However, IAI(+)/FIRS(+) group had a significantly higher rate of inflammation in each compartment than IAI(+)/FIRS(-) group in both PTL and preterm-PROM (each-for P < 0.05). We first demonstrated that PTL and preterm-PROM had a different pattern in the involved compartments of acute-HCA and/or funisitis in the IAI(-)/FIRS(--) group and in the change of involved compartments from IAI(-)/FIRS(-) to IAI(+)/FIRS(-).

Liver disease after intensive care of premature baboons: histopathologic observations

BACKGROUND AND OBJECTIVES

Cholestasis affects 50% of extremely low-birth-weight infants. Its etiology remains poorly understood and the extent of liver injury in these infants is unclear. The premature baboon model provides an opportunity to study neonatal liver disease. We characterize hepatic histopathologic changes in this model.

METHODS

Archival tissue and data were obtained from the Southwest Foundation for Biomedical Research Primate Center, San Antonio, TX. Animals were selected based on history of antenatal steroid therapy and absence of sepsis or necrotizing enterocolitis with a protocol duration of at least 21 days and no early death (n = 45). Baboons had been treated per protocol in the neonatal intensive care unit (NICU). At necropsy, liver tissue was harvested and stored. Tissues from fetal gestational controls at similar ages were used for comparison (n = 28). Histologic changes were scored by consensus of 2 pathologists blinded to treatment group. Descriptive and comparative statistics were performed.

RESULTS

Control fetal livers had extramedullary hematopoiesis (EMH) that decreased across the gestational range. There was evidence of hepatocyte iron storage and ongoing portal tract development. Livers of NICU-treated baboons had increased Kupffer cell hypertrophy and hemosiderosis. There was a shift away from erythroid EMH toward increased myeloid EMH. There was increased cholestasis, ductular proliferation, portal tract fibrosis, and steatosis in treated animals.

CONCLUSIONS

We found pathologic changes in NICU-treated baboons comparable with findings reported in human infants. The baboon model of prematurity may be a useful tool to explore cholestasis and liver dysfunction in extremely low-birth-weight infants.

Liver morphologic analysis in perinatal autopsies with intrauterine stress liver morphology in perinatal autopsies

Quantify steatosis, fibrosis, and focuses of extramedullary erythropoiesis (ER) in the liver and report it to the causes of death in the perinatal. Morphologic analysis of steatosis', percentage of fibrosis, and ER of 467 perinatal autopsies. Cases with hypoxia/perinatal anoxia and ascending infection showed higher percentage of fibrosis. The number of ER was significantly higher among premature infants and in cases with infection. Our results contribute to a better quality of perinatal care through clinical demonstration of which injuries are associated with them, what may help in early diagnosis of these alterations in children who survive.

The contribution of extramedullary hematopoiesis to hepatomegaly in anemic hydrops fetalis: a study in alpha-thalassemia hydrops fetalis

Massive hepatomegaly is a common finding in hydrops fetalis (HF) arising from hemoglobinopathies. It has been suggested that extramedullary hematopoiesis, which is markedly increased in response to anemia, plays a principal role in hepatomegaly via sinusoidal obstruction and distortion of the intrahepatic architecture. To test this concept, the authors compared 20 cases of α-thalassemia (hemoglobin Bart, 15 cases; hemoglobin H, 5 cases) with 19 cases of HF arising from other causes and 39 control nonhydrops cases. The mean liver weight in α-thalassemia cases was significantly heavier than in control cases and in hydrops fetalis cases due to other causes (P < 0.01). This was not explainable on the basis of extramedullary hematopoiesis (erythropoiesis or myelopoiesis) or hemosiderin deposition, since cases of HF from other causes, especially related to anemia, showed similar findings to α-thalassemia cases. While these processes no doubt contribute to hepatic weight, the major factor would still be high-output cardiac failure causing hepatic congestion.

Erythropoietin ameliorates damage to the placenta and fetal liver induced by exposure to lipopolysaccharide

Intrauterine infection and inflammation have been causally linked to preterm birth and fetal brain injury. Using an ovine model of endotoxin-induced brain injury we have recently shown that recombinant human erythropoietin (rhEPO) reduces brain injury and protects against damage to myelination in major myelinated axon tracts. Our present objective was to determine whether rhEPO is also protective of the placenta and the fetal liver, organs which could influence fetal well-being. At 107 +/- 1 days of gestational age (DGA) chronically catheterized fetal sheep were randomly assigned to receive, on 3 consecutive days, either: 1) an i.v. bolus dose of lipopolysaccharide (LPS; approximately 0.9 microg/kg; n = 8); 2) i.v. bolus dose of LPS, followed at 1 h by 5000 IU/kg of rhEPO (LPS + rhEPO, n = 8); 3) rhEPO (n = 3). Seven untreated fetuses served as controls (n = 7). The placenta and fetal liver were examined histologically at 116 +/- 1 DGA; a placental injury index was formulated comprising measures of placental area, apoptosis, tissue injury and the size of the intervillous space. In LPS-exposed fetuses this index was greater than in control or rhEPO alone fetuses (p < 0.02). Treatment of LPS-exposed fetuses with rhEPO resulted in a reduction in the index (p < 0.05) and in the extent of liver necrosis. We conclude that rhEPO offers protection to the placenta and fetal liver in the presence of acute inflammation.

What is adequate sampling of extraplacental membranes?: a randomized, prospective analysis

CONTEXT

It is the generally accepted practice to submit 1 or 2 membrane rolls when examining placentas.

OBJECTIVE

To determine whether obtaining additional sections would increase diagnostic yield and, if so, to what degree.

DESIGN

A membrane roll section was prospectively procured from each quadrant of its respective singleton placenta. These placentas were submitted for routine pathologic examination, the process of which was entirely separate from this study. All study sections were randomized and assigned new numbers, thereby blinding the pathologist to the placenta of origin. We evaluated the incidence of acute chorionitis/chorioamnionitis (AC/A) and atherosis when 1, 2, 3, or 4 slides were examined. The diagnostic yield from all possible combinations of single, pairs, and triplets of sections was tabulated. When an additional slide identified more extensive acute inflammation than what was demonstrated initially, the AC/A was upstaged.

RESULTS

With 1 section examined, 7 to 10 placentas had AC/A. With 2 sections, 10 to 15 placentas had AC/A; with 3 sections, 16 to 18 cases; and with 4 sections, 19 cases. Additional sections upstaged the AC/A diagnosis infrequently. A total of 4 of 53 placentas had atherosis, based on review of all 4 slides. One slide identified 1 to 3 cases of atherosis. With a second and third section, the yield increased to 2 to 4 and 3 to 4, respectively.

CONCLUSIONS

Review of a single membrane roll identified, at most, 53% of cases of AC/A and 50% of cases of atherosis. Additional sections increased the yield for both diagnoses in a roughly linear manner.