Contribution of apoptosis and apoptosis-related proteins to the malformation of the primitive intrahepatic biliary system in Meckel syndrome

Stillbirth Investigations: An Iconographic and Concise Diagnostic Workup in Perinatal Pathology

Introduction  Stillbirth is a dramatic event for the parents, health care team, and anyone close to the expectant parents. Multidisciplinary team (MDT) meetings are essential to improve communication in health care. We review the most frequent findings discussed at MDT meetings. Methods  A PubMed search was conducted through December 2021 since the inception (1965) using clinical queries with the key terms "stillbirth" AND "investigation" AND "pathology" AND "human." The search strategy included reviews, meta-analyses, randomized controlled trials, clinical trials, and observational studies. This systematic review is based on, but not limited to, the search results. It is the experience of more than 30 years of pediatrics, obstetrics, and pathology staff. Results  Two hundred and six articles were screened and complemented through the perusal of congressional activities and personal communications. Pathological findings following perinatal death can be divided into macroscopic, histologic, and placental findings. The placenta is crucial in fetal medicine and is key in determining the cause of stillbirth in a substantial number of events. Perinatal lung disease is essential to evaluate the response of newborns to extrauterine life and address newborns' outcomes appropriately. Conclusions  Stillbirth remains one of the less explored areas of medicine, and we can determine the cause in a limited number of cases. Nevertheless, placental pathology is critical in the etiology discovery pathway. Accurate investigations and discussion of photography-supported findings are vital in promoting communication at MDT meetings.

Mitochondrial Dysfunction and Induction of Apoptosis in Hepatocellular Carcinoma and Cholangiocarcinoma Cell Lines by Thymoquinone

Thymoquinone (TQ), a plant-based bioactive constituent derived from the volatile oil of Nigella sativa, has been shown to possess some anti-neoplastic activities. The present study aimed to investigate the mitochondria and apoptosis observed when TQ is applied against hepatocellular carcinoma (HepG2) and cholangiocarcinoma (HuCCT1) cells, two of the most common primary tumors of the liver. All cell lines were treated with increasing concentrations of TQ for varying durations. The anti-proliferative effect of TQ was measured using the methoxyphenyl-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and resulted in dose- and time-dependent growth inhibition in both cell lines. Cell cycle, apoptosis, and assessment of mitochondria viability by morphology assessment and evaluation of the mitochondrial membrane potential were investigated. The present study confirms that TQ caused cell cycle arrest at different phases and induced apoptosis in both cell lines. A systematic review of rodent animal models was also carried out. Overall, our data seem to represent the most robust results, suggesting that TQ possesses promising therapeutic potential as an anti-tumor agent for the treatment of hepatocellular carcinoma and cholangiocarcinoma.

Biliary Atresia Animal Models: Is the Needle in a Haystack?

Biliary atresia (BA) is a progressive fibro-obliterative process with a variable degree of inflammation involving the hepatobiliary system. Its consequences are incalculable for the patients, the affected families, relatives, and the healthcare system. Scientific communities have identified a rate of about 1 case per 10,000-20,000 live births, but the percentage may be higher, considering the late diagnoses. The etiology is heterogeneous. BA, which is considered in half of the causes leading to orthotopic liver transplantation, occurs in primates and non-primates. To consolidate any model, (1) more transport and cell membrane studies are needed to identify the exact mechanism of noxa-related hepatotoxicity; (2) an online platform may be key to share data from pilot projects and new techniques; and (3) the introduction of differentially expressed genes may be useful in investigating the liver metabolism to target the most intricate bilio-toxic effects of pharmaceutical drugs and toxins. As a challenge, such methodologies are still limited to very few centers, making the identification of highly functional animal models like finding a "needle in a haystack". This review compiles models from the haystack and hopes that a combinatorial search will eventually be the root for a successful pathway.

‘Teratoid’ Hepatoblastoma: An Intriguing Variant of Mixed Epithelial-Mesenchymal Hepatoblastoma

Liver neoplasms are quite rare in childhood. They often involve 6.7 cases per 10 million children aged 18 years or younger. Hepatoblastoma (HB) is the most frequent tumor, but this neoplasm’s rarity points essentially to the difficulty of performing biologic studies and large-scale therapeutic trials. On the pathological ground, HB is separated into an entirely epithelial neoplasm or a mixed neoplasm with epithelial and mesenchymal components. This last category has been further subdivided into harboring teratoid features or not. The ‘teratoid’ HB includes a mixture of components with heterologous origin. The heterologous components include neuroectoderm, endoderm, or melanin-holding cells with or without mesenchymal components. The most important criterium for the teratoid component is neuroepithelium, melanin, and, more recently, a yolk-sac-like component and neuroendocrine components. The mesenchymal components include muscle, osteoid, and cartilage, which are most often observed mainly in ‘teratoid’ neoplasms. The teratoid component or mesenchymal components are diagnosed with biopsies. They appear more prominent after chemotherapy due to the response and shrinkage of epithelial elements and non- or low-responsive components of mixed HB. This review focuses on the clinical, radiological, and pathological findings of HB with teratoid features.

Biliary Atresia: A Complex Hepatobiliary Disease with Variable Gene Involvement, Diagnostic Procedures, and Prognosis

The diagnosis of biliary atresia is still terrifying at the 3rd decade of the 21st century. In a department of neonatal intensive care unit, parents and physicians face a challenge with a jaundiced baby, who may or may not have a surgically correctable hepatopathy. The approach has been systematically evaluated, but the etiology remains ambiguous. The study of families with recurrent biliary atresia has been undertaken at a molecular level. The primary interest with this disease is to identify the etiology and change the treatment from symptomatic to curative. The occurrence of this obstructive cholangio-hepatopathy in well-known genetic syndromes has suggested just coincidental finding, but the reality can be more intriguing because some of these diseases may have some interaction with the development of the intrahepatic biliary system. Several genes have been investigated thoroughly, including ADD3 and GPC1 shifting the interest from viruses to genetics. In this review, the intriguing complexities of this hepatobiliary disease are highlighted.

Vitamin D supplementation for autoimmune hepatitis: A need for further investigation

Autoimmune hepatitis is a chronic liver disease harboring an autoimmune basis and progressive character. Despite still obscurity in etiology and pathogenesis, some evidence supports the importance of sustaining the immune system. Vitamin D is a lipo-soluble vitamin, which has been identified as decreased in our body. It is often due to the daily habit change and decrease of individual sun exposure due to the increase of the ultraviolet-induced potential melanocytic transformation. Here, we emphasize the importance of vitamin D supplementation in patients affected with liver disease.

Epigallocatechin-3-Gallate Toxicity in Children: A Potential and Current Toxicological Event in the Differential Diagnosis With Virus-Triggered Fulminant Hepatic Failure

The use of nutraceuticals is considerably increasing worldwide with a demand for organic and clean foods in the last two decades, which is probably incomparable with other periods of our civilization. The consistent application of nutraceuticals and so-called "superfood" may have remarkable effects on the prevention of several chronic diseases, including cancer. Moreover, the increased rate of overweight and obesity in Western countries does not spare childhood and youth, and the number of parents using natural remedies for preventing pediatric illness is vastly increasing worldwide. However, the overwhelming effects on diseases often overshadow the side effects of such nutrition, particularly in societies without millennial experience with botanicals and natural elements. Thus, the final result may be disastrous for some individuals. The liver is the most important and conspicuous target organ of numerous molecular compounds, and the cell damage is particularly striking on the infantile and pediatric liver due to the immaturity of the hepatocytes. Here, we target some generic data on fulminant hepatic failure, the benefits, and toxicity of epigallocatechin-3-gallate, which is one of the major components of green tea, and the histopathology of the "green-tea"-associated liver disease.

Road Map for Development of Stem Cell-Based Alternative Test Methods

Much progress has been made in establishing strategies for differentiation of induced human pluripotent stem cells (hiPSCs). However, differentiated hiPSCs are not yet routinely used for prediction of toxicity. Here, limiting factors are summarised and possibilities for improvement are discussed, with a focus on hepatocytes, cardiomyocytes, tubular epithelial cells, and developmental toxicity. Moreover, we make recommendations for further fine-tuning of differentiation protocols for hiPSCs to hepatocyte-like cells by comparing individual steps of currently available protocols to the mechanisms occurring during embryonic development. A road map is proposed to facilitate test system development, including a description of the most useful performance metrics.

Understanding the marvels behind liver regeneration

Tissue regeneration is a process by which the remaining cells of an injured organ regrow to offset the missed cells. This field is relatively a new discipline that has been a focus of intense research by clinicians, surgeons, and scientists for decades. It constitutes the cornerstone of tissue engineering, creation of artificial organs, and generation and utilization of therapeutic stem cells to undergo transformation to different types of mature cells. Many medical experts, scientists, biologists, and bioengineers have dedicated their efforts to deeply comprehend the process of liver regeneration, striving for harnessing it to invent new therapies for liver failure. Liver regeneration after partial hepatectomy in rodents has been extensively studied by researchers for many years. It is divided into three important distinctive phases including (a) Initiation or priming phase which includes an overexpression of specific genes to prepare the liver cells for replication, (b) Proliferation phase in which the liver cells undergo a series of cycles of cell division and expansion and finally, (c) termination phase which acts as brake to stop the regenerative process and prevent the liver tissue overgrowth. These events are well controlled by cytokines, growth factors, and signaling pathways. In this review, we describe the function, embryology, and anatomy of human liver, discuss the molecular basis of liver regeneration, elucidate the hepatocyte and cholangiocyte lineages mediating this process, explain the role of hepatic progenitor cells and elaborate the developmental signaling pathways and regulatory molecules required to procure a complete restoration of hepatic lobule. This article is categorized under: Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration Signaling Pathways > Global Signaling Mechanisms Gene Expression and Transcriptional Hierarchies > Cellular Differentiation.

MSX2 and BCL2 expressions in the development of anorectal malformations in ethylenethiourea-induced rat embryos

BACKGROUND

This study aimed to determine Msh homeobox 2 (MSX2) and B cell lymphoma-2 (BCL2) expression patterns during anorectal development in anorectal malformations (ARM) and normal rat embryos, with the goals of determining the role of MSX2 and BCL2 in ARM pathogenesis.

METHODS

ARM was induced in rat embryos with ethylenethiourea administered to dams on gestational day 10 (GD10). Embryos were harvested by cesarean deliveries from GD14 to GD16. MSX2 and BCL2 expression was evaluated via immunohistochemical staining, immunofluorescence, western blotting and quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Immunohistochemical staining of ARM embryos revealed that MSX2 was mainly expressed in the epithelium of the hindgut and urorectal septum (URS) on GD14. On GD15 and GD16, MSX2-immunolabeled cells were noted in the epithelium of the rectum, fistula and URS. However, in normal embryos, faint immunopositivity for MSX2 was demonstrated in the epithelium of the rectum and URS from GD14 to GD16. As for BCL2, in normal embryos, BCL2-immunopositive cells were extensively expressed in the epithelium of the hindgut and URS on GD14 and GD15. In ARM embryos, weak immunopositivity for BCL2 was detected in the epithelium of hindgut and URS on GD14 and GD15. Immunofluorescence revealed that MSX2 and BCL2 colocalized in the hindgut. In ARM embryos, we observed more MSX2-positive than BCL2-positive cells on GD14; the normal embryos had the opposite pattern. Analyses by western blot and qRT-PCR showed that MSX2 protein and mRNA expression was significantly increased in ARM embryos compared with the normal embryos on GD15 and GD16 (p < 0.05). However, BCL2 protein and mRNA expression was significantly decreased in ARM embryos compared with the normal embryos on GD14 (p < 0.05). The MSX2/BCL2 ratio of protein and mRNA expression level in the ARM group was the highest on GD15.

CONCLUSION

These results indicate that upregulation of MSX2 and downregulation of BCL2 during cloacal development into the rectum and urethra might be related to the ARM development, and MSX2 promoted apoptosis through reduction of BCL2 expression during the development of anorectal development in ARM.

Hepatocellular Carcinoma, Fibrolamellar Variant: Diagnostic Pathologic Criteria and Molecular Pathology Update. A Primer

Fibrolamellar hepatocellular carcinoma (FL-HCC) is generally a fairly rare event in routine pathology practice. This variant of hepatocellular carcinoma (HCC) is peculiarly intriguing and,in addition, poorly understood. Young people or children are often the target individuals with this type of cancer. Previously, I highlighted some pathology aspects of FL-HCC, but in this review, the distinctive clinico-pathologic features of FL-HCC and the diagnostic pathologic criteria of FL-HCC are fractionally reviewed and expanded upon. Further, molecular genetics update data with reference to this specific tumor are particularly highlighted as a primer for general pathologists and pediatric histopathologists. FL-HCC may present with metastases, and regional lymph nodes may be sites of metastatic spread. However, peritoneal and pulmonary metastatic foci have also been reported. To the best of our knowledge, FL-HCC was initially considered having an indolent course, but survival outcomes have recently been updated reconsidering the prognosis of this tumor. Patients seem to respond well to surgical resection, but recurrences are common. Thus, alternative therapies, such as chemotherapy and radiation, are ongoing. Overall, it seems that this aspect has not been well-studied for this variant of HCC and should be considered as target for future clinical trials. Remarkably, FL-HCC data seem to point to a liver neoplasm of uncertain origin and unveiled outcome. A functional chimeric transcript incorporating DNAJB1 and PRKACA was recently added to FL-HCC. This sensational result may give remarkable insights into the understanding of this rare disease and potentially provide the basis for its specific diagnostic marker. Detection of DNAJB1-PRKACA seems to be, indeed, a very sensitive and specific finding in supporting the diagnosis of FL-HCC. In a quite diffuse opinion, prognosis of this tumor should be reconsidered following the potentially mandatory application of new molecular biological tools.

Differential Expression of Sonic Hedgehog Protein in Human Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (CCA) are the two most common primary liver malignancies in adult patients. The molecular mechanisms underlying the pathogenesis of HCC and CCA are still poorly understood. Sonic hedgehog (SHH) signaling plays an essential role during mammalian development, i.e., promoting organ growth, tissue differentiation, and cell polarity. The upregulation of SHH has been observed during carcinogenesis, including colorectal carcinoma. Our aim was to investigate the expression pattern of SHH in HCC and CCA. We investigated 40 malignant tumors of the liver, including 21 HCC and 19 of intrahepatic CCA cases by immunohistochemistry (IHC) using a polyclonal antibody against SHH and Avidin-Biotin Complex method. We also investigated the co-localization of SHH and Bone morphogenetic protein 4 (BMP4) in CCA using indirect double IHC. Moreover, we examined whether SHH is expressed in two HCC cell lines HepG2 and HuH-7 and three CCA cell lines OZ, HuCCT1 and HuH28. We found that SHH was expressed in 15 out of 21 cases (71.4 %) of HCC and 100 % of CCA cases by immunohistochemistry. SHH expression showed a positive trend in liver tumors (HCC, CCA) with high grade (G2-G3). SHH localized to the epithelial cells, while BMP4 was expressed in the stromal cells in CCA by double IHC. However, both HCC and CCA cell lines showed SHH expression by Western blot analysis. In conclusion, SHH seems to be an interesting marker of de-differentiation in liver tumors and the simultaneous epithelial-mesenchymal expression may be an intriguing prompt to investigate cross-talks between SHH and BMP4.

Variable expressivity of ciliopathy neurological phenotypes that encompass Meckel-Gruber syndrome and Joubert syndrome is caused by complex de-regulated ciliogenesis, Shh and Wnt signalling defects

The ciliopathies are a group of heterogeneous diseases with considerable variations in phenotype for allelic conditions such as Meckel-Gruber syndrome (MKS) and Joubert syndrome (JBTS) even at the inter-individual level within families. In humans, mutations in TMEM67 (also known as MKS3) cause both MKS and JBTS, with TMEM67 encoding the orphan receptor meckelin (TMEM67) that localizes to the ciliary transition zone. We now describe the Tmem67(tm1(Dgen/H)) knockout mouse model that recapitulates the brain phenotypic variability of these human ciliopathies, with categorization of Tmem67 mutant animals into two phenotypic groups. An MKS-like incipient congenic group (F6 to F10) manifested very variable neurological features (including exencephaly, and frontal/occipital encephalocele) that were associated with the loss of primary cilia, diminished Shh signalling and dorsalization of the caudal neural tube. The 'MKS-like' group also had high de-regulated canonical Wnt/β-catenin signalling associated with hyper-activated Dishevelled-1 (Dvl-1) localized to the basal body. Conversely, a second fully congenic group (F > 10) had less variable features pathognomonic for JBTS (including cerebellar hypoplasia), and retention of abnormal bulbous cilia associated with mild neural tube ventralization. The 'JBTS-like' group had de-regulated low levels of canonical Wnt signalling associated with the loss of Dvl-1 localization to the basal body. Our results suggest that modifier alleles partially determine the variation between MKS and JBTS, implicating the interaction between Dvl-1 and meckelin, or other components of the ciliary transition zone. The Tmem67(tm1(Dgen/H)) line is unique in modelling the variable expressivity of phenotypes in these two ciliopathies.

Ductal plates in hepatic ductular reactions. Hypothesis and implications. III. Implications for liver pathology

This article discusses on the basis of the ductal plate hypothesis the implication of the concept for several liver abnormalities. The occurrence of ductal plates (DP) during liver growth in childhood would explain the paraportal and parenchymal localizations of von Meyenburg complexes in postnatally developed parts of the liver, and their higher incidence in adulthood versus childhood. It partly clarifies the lack of postnatal intrahepatic bile duct development in Alagille syndrome and the reduced number of portal tracts in this disease. Ductular reactions (DRs) in DP configuration are the predominant type of progenitor cell reaction in fulminant necro-inflammatory liver disease, when lack of sufficient parenchymal regeneration results in liver failure. The concept of dissecting DRs explains the micronodular pattern of advanced biliary and alcoholic cirrhosis. The concept explains the DP patterns of bile ducts in several cases of biliary atresia, with implications for diagnosis and prognosis. The hypothesis also has an impact on concepts about stem/progenitor cells and their niche.

Ductal plates in hepatic ductular reactions. Hypothesis and implications. III. Implications for liver pathology

This article discusses on the basis of the ductal plate hypothesis the implication of the concept for several liver abnormalities. The occurrence of ductal plates (DP) during liver growth in childhood would explain the paraportal and parenchymal localizations of von Meyenburg complexes in postnatally developed parts of the liver, and their higher incidence in adulthood versus childhood. It partly clarifies the lack of postnatal intrahepatic bile duct development in Alagille syndrome and the reduced number of portal tracts in this disease. Ductular reactions (DRs) in DP configuration are the predominant type of progenitor cell reaction in fulminant necro-inflammatory liver disease, when lack of sufficient parenchymal regeneration results in liver failure. The concept of dissecting DRs explains the micronodular pattern of advanced biliary and alcoholic cirrhosis. The concept explains the DP patterns of bile ducts in several cases of biliary atresia, with implications for diagnosis and prognosis. The hypothesis also has an impact on concepts about stem/progenitor cells and their niche.

Immunohistochemical detection of polyductin and co-localization with liver progenitor cell markers during normal and abnormal development of the intrahepatic biliary system and in adult hepatobiliary carcinomas

The longest open reading frame of PKHD1 (polycystic kidney and hepatic disease 1), the autosomal recessive polycystic kidney disease (ARPKD) gene, encodes a single-pass, integral membrane protein named polyductin or fibrocystin. A fusion protein comprising its intracellular C-terminus, FP2, was previously used to raise a polyclonal antiserum shown to detect polyductin in several human tissues, including liver. In the current study, we aimed to investigate by immunohistochemistry the detailed polyductin localization pattern in normal (ductal plate [DP], remodelling ductal plate [RDP], remodelled bile ducts) and abnormal development of the primitive intrahepatic biliary system, known as ductal plate malformation (DPM). This work also included the characterization of polyductin expression profile in various histological forms of neonatal and infantile cholestasis, and in cholangiocellular carcinoma (CCC) and hepatocellular carcinoma (HCC). We detected polyductin expression in the intrahepatic biliary system during the DP and the RDP stages as well as in DPM. No specific staining was found at the stage of remodelled bile ducts. Polyductin was also detected in liver biopsies with neonatal cholestasis, including mainly biliary atresia and neonatal hepatitis with ductular reaction as well as congenital hepatic fibrosis. In addition, polyductin was present in CCC, whereas it was absent in HCC. Polyductin was also co-localized in some DP cells together with oval stem cell markers. These results represent the first systematic study of polyductin expression in human pathologies associated with abnormal development of intrahepatic biliary tree, and support the following conclusions: (i) polyductin expression mirrors developmental properties of the primitive intrahepatic biliary system; (ii) polyductin is re-expressed in pathological conditions associated with DPM and (iii) polyductin might be a potential marker to distinguish CCC from HCC.

Bile duct to portal space ratio and ductal plate remnants in liver disease of infants aged less than 1 year

AIM

To validate the bile duct to portal space ratio as an independent factor useful for the prognosis of neonatal liver disease.

METHODS

We assessed the maturation of the intrahepatic bile duct system (IBDS) in 87 consecutive infants aged less than 1 year undergoing non-subcapsular, adequate (at least six portal tracts), liver needle biopsies because of hepatomegaly and/or cholestasis. The maturation of the IBDS was evaluated by immunohistochemistry with an antibody directed to cytokeratin 7 (CK7), a biliary-type intermediate filament of the cytoskeleton, and a schema showing the IBDS remodelling. We used five categories to fit the different patterns of the IBDS remodelling using the ratio between the number of bile ducts and the number of portal tracts (BD/PT) and the presence of abnormal reaction patterns (marked intra-acinar pseudorosettes and/or periportal ductular proliferation): (A) abnormal reaction patterns with any BD/PT; (B) BD/PT = 0; (C) 0.1 < or = BD/PT < 0.5; (D) 0.5 < or = BD/PT < 0.9; and (E) BD/PT > 0.9 (B-E categories: no abnormal reaction patterns). Further, we evaluated cholestasis, portal fibrosis (PF), portal inflammation (PI), giant cell transformation (GCT), and extramedullary haematopoiesis (EMH).

RESULTS

We identified A-E categories in 24, 14, 17, 8, and 24 biopsies, respectively. B and C categories were frequently observed in biliary atresia (BA), A category in neonatal hepatitis (NH), A-C categories in paucity of intrahepatic bile ducts (PIBD), and E category in 'other liver diseases' (OLD). Cholestasis, PI, GCT, and EMH were more frequent in A and C, while PF was variably seen in all categories. The lowest survival rate occurred in B (Kaplan-Meier estimator).

CONCLUSIONS

(1) Biliary epithelial cell patterns recapitulate the primitive stages of the IBDS maturation; (2) abnormal reaction patterns occur mainly in NH, whilst BD/PT < 0.5 in BA; and (3) lack of intrahepatic bile ducts in infants aged less than 1 year is an adverse prognostic factor independent from aetiology of neonatal liver disease.

Lack of cilia and differentiation defects in the liver of human foetuses with the Meckel syndrome

BACKGROUND/AIMS

Meckel syndrome is an autosomal-recessive disease characterized by a combination of renal cysts, anomalies of the central nervous system, polydactyly and ductal plate malformations (DPM), which are hepatic anomalies consisting of excessive and abnormal foetal biliary structures. Among the genomic loci associated with Meckel syndrome, mutations in four genes were recently identified. These genes code for proteins associated with primary cilia and are possibly involved in cell differentiation. The aim of the present work was to investigate the formation of the primary cilia and the differentiation of the hepatic cells in foetuses with Meckel syndrome.

METHODS

Sections of livers from human foetuses with Meckel syndrome were analysed by immunofluorescence, immunohistochemistry and electron microscopy.

RESULTS

The primary cilia of the biliary cells were absent in some Meckel foetuses, but were present in others. In addition, defects in hepatic differentiation were observed in Meckel livers, as evidenced by the presence of hybrid cells co-expressing hepatocytic and biliary markers.

CONCLUSIONS

Defects in cilia formation occur in some Meckel livers, and most cases show DPM associated with abnormal hepatic cell differentiation. Because differentiation precedes the formation of the cilia during liver development, we propose that defective differentiation may constitute the initial defect in the liver of Meckel syndrome foetuses.

Transcriptional profiling implicates TGFbeta/BMP and Notch signaling pathways in ductular differentiation of fetal murine hepatoblasts

Bile duct morphogenesis involves sequential induction of biliary specific gene expression, bilayer generation, cell proliferation, remodeling and apoptosis. HBC-3 cells are a model system to study differentiation of hepatoblasts along the hepatocytic or bile ductular lineage in vitro and in vivo. We used microarray to define molecular pathways during ductular differentiation in response to Matrigel. The temporal pattern of expression of marker genes induced was similar to that observed during bile duct formation in vivo. Notch, HNF1beta, Polycystic kidney disease 2, Bicaudal C 1 and beta-catenin were up regulated during the time course. Functional clustering analysis revealed significant up regulation of clusters of genes involved in extracellular matrix remodeling, ion transport, vacuoles, lytic vacuoles, pro-apoptotic and anti-apoptotic genes, transcription factors and negative regulators of the cell proliferation, while genes involved in the cell cycle were significantly down regulated. Notch signaling pathway was activated by treatment with Matrigel. In addition, TGFbeta/BMP signaling pathway members including the type I TGFbeta receptor and Smads 3, 4 and 5 were significantly up regulated, as were several TGFbeta/BMP responsive genes including Hey 1, a regulator of Notch pathway signaling. SMADS 3, 4 and 5 were present in the nuclear fraction of HBC-3 cells during ductular differentiation in vitro, but not during hepatocyte differentiation. SMAD 5 was preferentially expressed in hepatoblasts undergoing bile duct morphogenesis in the fetal liver, while the TGFbeta/BMP signaling antagonist chordin, was expressed throughout the liver suggesting a mechanism by which TGFbeta/BMP signaling is limited to hepatoblasts that contact portal mesenchyme in vivo.

An immunohistochemical study of human fetal liver in the Meckel-Gruber syndrome

AIMS

The ductal plate abnormality of the liver in fetuses with the Meckel-Gruber syndrome has been well characterised, but its aetiology remains unknown. We have analysed liver structure in six fetuses with this syndrome, using routine histology, immunocytochemistry, and electron microscopy.

METHODS

Liver tissue from six fetuses of 11-27 weeks gestational age was examined by immunoperoxidase staining with antigens to cyokeratin (AE1/3) and polyclonal CEA. We also examined the ultrastructure of the syndromic fetal liver. The findings were compared with livers of control fetuses obtained from miscarriages, of similar size and gestational age but without dysmorphic features or developmental anomalies.

RESULTS

The ductal plate abnormality was present in all the fetuses with the Meckel-Gruber syndrome. There were abnormalities of biliary excretion in all syndromic fetuses. Ultrastructural studies of the portal tract revealed abnormal collagen bundles in the Meckel-Gruber syndrome.

CONCLUSIONS

Our findings, in conjunction with other reports in the literature, suggest that the ductal plate abnormality may be caused by failure of anastomosis of the intra- and extrahepatic biliary systems, perhaps in association with abnormalities of the portal tract stroma and biliary excretion.

Human brain of preterm infants after hypoxic-ischaemic injuries: no evidence of a substantial role for apoptosis by using a fine-tuned ultrasound-guided neuropathological analysis

Preterm birth may be associated with hypoxic-ischaemic encephalopathy (HIE) showing a well recognised number of patterns, including neuronal karyorrhexis/eosinophilia mostly at the diencephalon and brain stem and leukomalacia at the periventricular white matter. To investigate whether programmed cell death or apoptosis plays a role in HIE, we examined human brains of preterm infants. Brain tissue samples from 12 consecutive infants (24-34 weeks of gestation) were available at post-mortem examination (1998-2000) after approval of the Ethics Committee. Two tissue sections were stereologically localised after brain fixation, slice preparation, and comparison with ultrasound imaging. We studied the periventricular white matter and the corresponding cortical region in each brain. Conventional histological stains were used. In addition, apoptosis was detected using a neuronal-specific terminal deoxynucleotidyl transferase-mediated nick end-labelling (TUNEL) method (NeuroTACS). A semiquantitative evaluation was performed to compare regions close to brain lesions with injury-free areas. Neuronal apoptosis was low in both cortical and in periventricular regions. No glial apoptosis was detected. Apoptosis in neurones was, however, detected in preterm brains with bacterial or mycotic infection. These results point out to the ambiguity of the TUNEL-reactive neurons in the diseased premature infants using fine-tuned ultrasound-guided neuropathological analysis, support the probable coexistence of neuronal TUNEL-reactivity and infection, and suggest that the association between apoptosis and HIE should overall be viewed with more caution.

Hepatic artery malformations associated with a primary defect in intrahepatic bile duct development

BACKGROUND/AIMS

The portal tracts contain bile ducts associated with branches of the portal vein and of the hepatic artery. Hepatic artery malformations are found in diseases in which fetal biliary structures persist after birth (ductal plate malformations). Here we investigated how hepatic artery malformations relate to abnormal bile duct development.

METHODS

Hepatic artery and biliary development was analyzed in fetuses with Jeune syndrome or Meckel syndrome, which show ductal plate malformations. We also analyzed hepatic artery development in transgenic mice which exhibit biliary anomalies following inactivation of the genes for hepatocyte nuclear factor (HNF)-6 or HNF-1beta, two transcription factors expressed in biliary cells, but not in arteries.

RESULTS

We show that arterial anomalies occurred in fetuses with Jeune syndrome or Meckel syndrome. We provide the first description of hepatic artery branch development in the mouse and show that inactivation of the Hnf6 or Hnf1beta gene results in anomalies of the hepatic artery branches. In the transgenic mice and in the human syndromes, the biliary anomalies preceded the arterial anomalies.

CONCLUSIONS

A primary defect in biliary epithelial cells is associated with hepatic artery malformations in mice. Our data provide a model to interpret and study hepatic artery anomalies in humans.

Molecular pathology and genetics of congenital hepatorenal fibrocystic syndromes

The hepatorenal fibrocystic (HRFC) syndromes are a heterogeneous group of severe monogenic conditions that may be detected before birth. Commonly, HRFC syndromes present in the neonatal and paediatric age, with consistent developmental abnormalities mostly involving the liver and kidney. The changes include the proliferation and dilatation of epithelial ducts in these tissues with abnormal deposition of extracellular matrix. In this review, we examine the clinical features and differential diagnoses of this group of syndromes, including autosomal recessive polycystic kidney disease (ARPKD), juvenile nephronophthisis (NPHP), Meckel-Gruber syndrome (MKS), Bardet-Biedl syndrome (BBS), and Jeune asphyxiating thoracic dystrophy (JATD). Extrahepatic manifestations include mostly bone and central nervous system abnormalities, dysmorphic features, and developmental delay. Previously, it has been suggested that ARPKD, JATD, and Ellis-van Creveld syndrome (EvC) may arise from defects in differentiation in a common developmental pathway. We review recent molecular advances in the recessive HRFC syndromes and discuss this hypothesis.

Hepatic failure with neonatal tissue siderosis of hemochromatotic type in an infant presenting with meconium ileus. Case report and differential diagnosis of the perinatal iron storage disorders

We report on a female preterm infant with hepatic failure and neonatal tissue siderosis of hemochromatotic type diagnosed by using both histochemistry and atomic absorption spectroscopy. The infant presented with meconium ileus, signs of rapidly progressive hepatic failure, and hyperferritinemia (7132 ng/ml). Despite surgery and intensive care the infant died 32 days after birth. Postmortem examination showed a wrinkled liver with extensive collapse of the hepatic architecture and regenerating nodules as well as hepatic and extrahepatic iron accumulation of hemochromatotic type, sparing the reticuloendothelial system. Atomic absorption spectroscopy confirmed an increase in the iron content of various organs: liver, heart, pancreas, oral salivary gland, kidney, and adrenal gland. The increase in the iron content of various organs was determined by comparing the analysis of the propositus with those of 5 gestationally age-related preterm infants who had died in the intensive care unit: 2 died of meconium aspiration syndrome, the other 3 of hyaline membrane disease, bronchopulmonary dysplasia, and immaturity, respectively. We also compared the analysis of 15 fetuses having a a condition predisposing to iron accumulation (trisomy 21, trisomy 18, cytomegalovirus, amnion infection syndrome, Rhesus- and ABO-incompatibility, congenital hemolysis, anti-phospholipid syndrome, congenital heart disease). Delta F508, the most frequent mutation seen in cystic fibrosis patients, was excluded by gene sequencing. Different noxae causing iron accumulation in the neonatal period have led to the statement that neonatal hemochromatosis may collect different etiologies, such as metabolic disorders, infections, chromosomal aberrations, and immunological disorders. In this study, we report the singular evidence of neonatal iron accumulation of hemochromatotic type in an infant presenting with meconium ileus and propose a classification of the neonatal disorders associated with iron accumulation.

Accessory liver in an infant with congenital diaphragmatic hernia

Incidence of congenital diaphragmatic hernia (CDH) ranges from 1 in 2,400 to one in 5,000 live births. Associated anomalies in CDH are approximately 30% to 35%. The authors report on an infant with CDH and an accessory supradiaphragmatic liver with separate vascularization from the thoracic aorta. The pathogenesis of this malformation is discussed. The postoperative course and the follow-up of the child over 5 years was completely uneventful.

Immunohistochemical localization of transforming growth factor-alpha and epithelial growth factor receptor in human fetal developing skin, psoriasis and restrictive dermopathy

Keratinocytes release a number of cytokines interacting with other intra- and subepidermal cells during the initiation and the perpetuation of skin inflammatory reactions. Cultured human keratinocytes overexpressing the transforming growth factor alpha (TGF-alpha) assumed a spindled morphology and displayed increased locomotion. Moreover, the receptor for TGF-alpha, the epithelial growth factor receptor (EGFR), is important for autocrine growth, promotion of cell survival, and regulation of cell migration. The expression of TGF-alpha and EGFR has not been widely studied in human developing skin and their roles in geno-dermatosis are not known. In this study, we investigated the expression of TGF-alpha and EGFR by immunohistochemistry in human developing skin at different gestational ages (14 th week, 20 th week, and 34 th week), in six patients with psoriasis, and, for the first time, in an infant affected with restrictive dermopathy, a very rare lethal genodermatosis, characterized by abnormal skin growth and differentiation with thin, tightly adherent skin. TGF-alpha and EGFR were expressed in the basal layer at the 14 th week and in all epidermal layers at the 20 th and 34 th week of gestation. In psoriasis, TGF-alpha was overexpressed in all layers of epidermis, while EGFR was expressed in the basal and first suprabasal layers. In restrictive dermopathy, we observed no expression of both TGF-alpha and EGFR at the level of the skin. The other organs showed comparable patterns to those of an age-matched infant. In conclusion, TGF-alpha and EGFR interact strictly to promote skin development during the intrauterine life. An interactive autocrine growth cycle between TGF-alpha and EGFR is present in psoriasis. A skin-localized alteration of the expression of TGF-alpha and EGFR may be at the basis of restrictive dermopathy. The delay of growth and differentiation of the skin in restrictive dermopathy may be related to the absent expression of TGF-alpha, which is probably due to a down regulation of EGFR by an abnormal autocrine mechanism.

Polycystic kidney rat is a novel animal model of Caroli's disease associated with congenital hepatic fibrosis

Caroli's disease (congenital intrahepatic biliary dilatation) associated with congenital hepatic fibrosis is an autosomal recessive polycystic kidney disease. Recently, the polycystic kidney (PCK) rat, a spontaneous mutant derived from a colony of CRJ:CD rats with polycystic lesions in the liver and an autosomal recessive mode of inheritance, was reported. In the present study, the pathology of the hepatobiliary system and the biliary cell-kinetics were evaluated in fetuses (day 18 to 21 of gestation) and neonates and adults (1 day to 4 months after delivery) of PCK rats. CRJ:CD rats were used as a control. Multiple segmental and saccular dilatations of intrahepatic bile ducts were first observed in fetuses at 19 days of gestation. The dilatation spread throughout the liver and the degree of dilatation increased with aging. Gross and histological features characterizing ductal plate malformation were common in the intrahepatic bile ducts. Overgrowth of portal connective tissue was evident and progressive after delivery. These features were very similar to those of Caroli's disease with congenital hepatic fibrosis. Proliferative activity in the biliary epithelial cells was greater in PCK rats than controls during the development. In contrast, the biliary epithelial apoptosis was less extensive in PCK rats than the controls until 1 week after delivery, but greater after 3 weeks, suggesting that the remodeling defect in immature bile ducts associated with the imbalance of cell kinetics plays a role in the occurrence of intrahepatic biliary anomalies in PCK rats. The PCK rat could be a useful and promising animal model of Caroli's disease with congenital hepatic fibrosis.