Cosmic-ray antinuclei as messengers of new physics: status and outlook for the new decade

The precise measurement of cosmic-ray antinuclei serves as an important means for identifying the nature of dark matter and other new astrophysical phenomena, and could be used with other cosmic-ray species to understand cosmic-ray production and propagation in the Galaxy. For instance, low-energy antideuterons would provide a "smoking gun" signature of dark matter annihilation or decay, essentially free of astrophysical background. Studies in recent years have emphasized that models for cosmic-ray antideuterons must be considered together with the abundant cosmic antiprotons and any potential observation of antihelium. Therefore, a second dedicated Antideuteron Workshop was organized at UCLA in March 2019, bringing together a community of theorists and experimentalists to review the status of current observations of cosmic-ray antinuclei, the theoretical work towards understanding these signatures, and the potential of upcoming measurements to illuminate ongoing controversies. This review aims to synthesize this recent work and present implications for the upcoming decade of antinuclei observations and searches. This includes discussion of a possible dark matter signature in the AMS-02 antiproton spectrum, the most recent limits from BESS Polar-II on the cosmic antideuteron flux, and reports of candidate antihelium events by AMS-02; recent collider and cosmic-ray measurements relevant for antinuclei production models; the state of cosmic-ray transport models in light of AMS-02 and Voyager data; and the prospects for upcoming experiments, such as GAPS. This provides a roadmap for progress on cosmic antinuclei signatures of dark matter in the coming years.

HCV infection and the risk of head and neck cancer: A meta-analysis

Recent evidence has consistently suggested a role for HCV in the etiology of head and neck squamous cell carcinoma (HNSCC), but the conclusions of these studies have often been limited by small sample size. Therefore, a meta-analysis was performed to summarize present evidence on the association between HCV infection and HNSCC. After screening citations from literature search, eight observational studies investigating the association between HCV and cancer(s) of either oral cavity, oropharynx, hypopharynx or larynx were included. For each cancer site, risk ratios from individual studies were displayed in forest plots; pooled risk ratios (RR) and corresponding confidence intervals (CI) were calculated. A significant association was found between HCV infection and cancers of the oral cavity (RR = 2.13; 95%: 1.61-2.83), oropharynx (RR = 1.81; 95% CI: 1.21-2.72), and larynx (RR = 2.57; 95% CI: 1.11-5.94). A similar picture emerged for hypopharyngeal cancer, though this result did not fully reach statistical significance because of the small number of available studies (RR = 2.15; 95% CI: 0.73-6.31). These findings remained similar after exclusion of patients with HIV co-infection. Our results highlighted the importance of surveillance of the upper aerodigestive tract in patients with known chronic HCV infections in order to enable HNSCC early diagnosis. In addition, they could be a reminder of the possibility of undiagnosed HCV infection to the clinicians treating HNSCC.

The Emerging Role of Macrophages in Chronic Cholangiopathies Featuring Biliary Fibrosis: An Attractive Therapeutic Target for Orphan Diseases

Cholangiopathies are a heterogeneous group of chronic liver diseases caused by different types of injury targeting the biliary epithelium, such as genetic defects and immune-mediated attacks. Notably, most cholangiopathies are orphan, thereby representing one of the major gaps in knowledge of the modern hepatology. A typical hallmark of disease progression in cholangiopathies is portal scarring, and thus development of effective therapeutic approaches would aim to hinder cellular and molecular mechanisms underpinning biliary fibrogenesis. Recent lines of evidence indicate that macrophages, rather than more conventional cell effectors of liver fibrosis such as hepatic stellate cells and portal fibroblasts, are actively involved in the earliest stages of biliary fibrogenesis by exchanging a multitude of cues with cholangiocytes, which promote their recruitment from the circulating compartment owing to a senescent or an immature epithelial phenotype. Two cholangiopathies, namely primary sclerosing cholangitis and congenital hepatic fibrosis, are paradigmatic of this mechanism. This review summarizes current understandings of the cytokine and extracellular vesicles-mediated communications between cholangiocytes and macrophages typically occurring in the two cholangiopathies to unveil potential novel targets for the treatment of biliary fibrosis.

Necroptosis in Cholangiocarcinoma

Necroptosis is a type of regulated cell death that is increasingly being recognized as a relevant pathway in different pathological conditions. Necroptosis can occur in response to multiple stimuli, is triggered by the activation of death receptors, and is regulated by receptor-interacting protein kinases 1 and 3 and mixed-lineage kinase domain-like, which form a regulatory complex called the necrosome. Accumulating evidence suggests that necroptosis plays a complex role in cancer, which is likely context-dependent and can vary among different types of neoplasms. Necroptosis serves as an alternative mode of programmed cell death overcoming apoptosis and, as a pro-inflammatory death type, it may inhibit tumor progression by releasing damage-associated molecular patterns to elicit robust cross-priming of anti-tumor CD8+ T cells. The development of therapeutic strategies triggering necroptosis shows great potential for anti-cancer therapy. In this review, we summarize the current knowledge on necroptosis and its role in liver biliary neoplasms, underlying the potential of targeting necroptosis components for cancer treatment.

Modulation of the Tryptophan Hydroxylase 1/Monoamine Oxidase-A/5-Hydroxytryptamine/5-Hydroxytryptamine Receptor 2A/2B/2C Axis Regulates Biliary Proliferation and Liver Fibrosis During Cholestasis

BACKGROUND AND AIMS

Serotonin (5HT) is a neuroendocrine hormone synthetized in the central nervous system (CNS) as well as enterochromaffin cells of the gastrointestinal tract. Tryptophan hydroxylase (TPH1) and monoamine oxidase (MAO-A) are the key enzymes for the synthesis and catabolism of 5HT, respectively. Previous studies demonstrated that 5-hydroxytryptamine receptor (5HTR)1A/1B receptor agonists inhibit biliary hyperplasia in bile-duct ligated (BDL) rats, whereas 5HTR2B receptor antagonists attenuate liver fibrosis (LF) in mice. Our aim was to evaluate the role of 5HTR2A/2B/2C agonists/antagonists in cholestatic models.

APPROACH AND RESULTS

While in vivo studies were performed in BDL rats and the multidrug resistance gene 2 knockout (Mdr2-/- ) mouse model of PSC, in vitro studies were performed in cell lines of cholangiocytes and hepatic stellate cells (HSCs). 5HTR2A/2B/2C and MAO-A/TPH1 are expressed in cholangiocytes and HSCs from BDL rats and Mdr2-/- - mice. Ductular reaction, LF, as well as the mRNA expression of proinflammatory genes increased in normal, BDL rats, and Mdr2-/- - mice following treatment 5HTR2A/2B/2C agonists, but decreased when BDL rats and Mdr2-/- mice were treated with 5HTR2A/2B/2C antagonists compared to BDL rats and Mdr2-/- mice, respectively. 5HT levels increase in Mdr2-/- mice and in PSC human patients compared to their controls and decrease in serum of Mdr2-/- mice treated with 5HTR2A/2B/2C antagonists compared to untreated Mdr2-/- mice. In vitro, cell lines of murine cholangiocytes and human HSCs express 5HTR2A/2B/2C and MAO-A/TPH1; treatment of these cell lines with 5HTR2A/2B/2C antagonists or TPH1 inhibitor decreased 5HT levels as well as expression of fibrosis and inflammation genes compared to controls.

CONCLUSIONS

Modulation of the TPH1/MAO-A/5HT/5HTR2A/2B/2C axis may represent a therapeutic approach for management of cholangiopathies, including PSC.

Clinical outcome indicators in chronic hepatitis B and C: A primer for value-based medicine in hepatology

BACKGROUND & AIMS

Chronic liver diseases (CLDs) are major health problems that require complex and costly treatments. Liver-specific clinical outcome indicators (COIs) able to assist both clinicians and administrators in improving the value of care are presently lacking. The Value-Based Medicine in Hepatology (VBMH) study aims to fill this gap, devising and testing a set of COIs for CLD, that could be easily collected during clinical practice. Here we report the COIs generated and recorded for patients with HBV or HCV infection at different stages of the disease.

METHODS/RESULTS

In the first phase of VBMH study, COIs were identified, based on current international guidelines and literature, using a modified Delphi method and a RAND 9-point appropriateness scale. In the second phase, COIs were tested in an observational, longitudinal, prospective, multicentre study based in Lombardy, Italy. Eighteen COIs were identified for HBV and HCV patients. Patients with CLD secondary to HBV (547) or HCV (1391) were enrolled over an 18-month period and followed for a median of 4 years. The estimation of the proposed COIs was feasible in the real-word clinical practice and COI values compared well with literature data. Further, the COIs were able to capture the impact of new effective treatments like direct-acting antivirals (DAAs) in the clinical practice.

CONCLUSIONS

The COIs efficiently measured clinical outcomes at different stages of CLDs. While specific clinical practice settings and related healthcare systems may modify their implementation, these indicators will represent an important component of the tools for a value-based approach in hepatology and will positively affect care delivery.

Effect of Gestational Age on Maternofetal Vascular Function Following Single Maternal Engineered Nanoparticle Exposure

Normal pregnancy outcome is accomplished, in part, by rapid and expansive physiological adaptations to the systemic circulation, the extent of which is specific to gestational day (GD) and anatomical location. Pregnancy-related hemodynamic changes in uterine placental blood flow stimulate compensatory vascular signaling and remodeling that begins early and continues throughout gestation. Exposure of the maternal environment to engineered nanomaterials (ENM) during pregnancy has been shown to impact health of the dam, fetus, and adult offspring; however, the consequences of specific temporal (gestational age) and spatial (vascular location) considerations are largely undetermined. We exposed pregnant Sprague-Dawley rats to nano-TiO2 aerosols at three critical periods of fetal development (GD 4, 12, and 17) to identify vascular perturbations associated with ENM exposure at these developmental milestones. Vascular reactivity of the maternal thoracic aorta, the uterine artery, the umbilical vein, and the fetal thoracic aorta were evaluated using wire myography on GD 20. While impairments were noted at each level of the maternofetal vascular tree and at each exposure day, our results indicate the greatest effects may be identified within the fetal vasculature (umbilical vein and fetal aorta), wherein effects of a single maternal inhalational exposure to nano-TiO2 on GD 4 modified responses to cholinergic, NO, and α-adrenergic signaling.

Pathobiology of inherited biliary diseases: a roadmap to understand acquired liver diseases

Bile duct epithelial cells, also known as cholangiocytes, regulate the composition of bile and its flow. Acquired, congenital and genetic dysfunctions in these cells give rise to a set of diverse and complex diseases, often of unknown aetiology, called cholangiopathies. New knowledge has been steadily acquired about genetic and congenital cholangiopathies, and this has led to a better understanding of the mechanisms of acquired cholangiopathies. This Review focuses on findings from studies on Alagille syndrome, polycystic liver diseases, fibropolycystic liver diseases (Caroli disease and congenital hepatic fibrosis) and cystic fibrosis-related liver disease. In particular, knowledge on the role of Notch signalling in biliary repair and tubulogenesis has been advanced by work on Alagille syndrome, and investigations in polycystic liver diseases have highlighted the role of primary cilia in biliary pathophysiology and the concept of biliary angiogenic signalling and its role in cyst growth and biliary repair. In fibropolycystic liver disease, research has shown that loss of fibrocystin generates a signalling cascade that increases β-catenin signalling, activates the NOD-, LRR- and pyrin domain-containing 3 inflammasome, and promotes production of IL-1β and other chemokines that attract macrophages and orchestrate the process of pericystic and portal fibrosis, which are the main mechanisms of progression in cholangiopathies. In cystic fibrosis-related liver disease, lack of cystic fibrosis transmembrane conductance regulator increases the sensitivity of epithelial Toll-like receptor 4 that sustains the secretion of nuclear factor-κB-dependent cytokines and peribiliary inflammation in response to gut-derived products, providing a model for primary sclerosing cholangitis. These signalling mechanisms may be targeted therapeutically and they offer a possibility for the development of novel treatments for acquired cholangiopathies.

Identification and quantification of gold engineered nanomaterials and impaired fluid transfer across the rat placenta via ex vivo perfusion

Development and implementation of products incorporating nanoparticles are occurring at a rapid pace. These particles are widely utilized in domestic, occupational, and biomedical applications. Currently, it is unclear if pregnant women will be able to take advantage of the potential biomedical nanoproducts out of concerns associated with placental transfer and fetal interactions. We recently developed an ex vivo rat placental perfusion technique to allow for the evaluation of xenobiotic transfer and placental physiological perturbations. In this study, a segment of the uterine horn and associated placenta was isolated from pregnant (gestational day 20) Sprague-Dawley rats and placed into a modified pressure myography vessel chamber. The proximal and distal ends of the maternal uterine artery and the vessels of the umbilical cord were cannulated, secured, and perfused with physiological salt solution (PSS). The proximal uterine artery and umbilical artery were pressurized at 80 mmHg and 50 mmHg, respectively, to allow countercurrent flow through the placenta. After equilibration, a single 900 μL bolus dose of 20 nm gold engineered nanoparticles (Au-ENM) was introduced into the proximal maternal artery. Distal uterine and umbilical vein effluents were collected every 10 min for 180 min to measure placental fluid dynamics. The quantification of Au-ENM transfer was conducted via inductively coupled plasma mass spectrometry (ICP-MS). Overall, we were able to measure Au-ENM within uterine and umbilical effluent with 20 min of material infusion. This novel methodology may be widely incorporated into studies of pharmacology, toxicology, and placental physiology.

Secretin/secretin receptor signaling mediates biliary damage and liver fibrosis in early-stage primary biliary cholangitis

Primary biliary cholangitis (PBC) primarily targets cholangiocytes and is characterized by liver fibrosis and biliary proliferation. Activation of the secretin (Sct)/secretin receptor (SR) axis, expressed only by cholangiocytes, increases biliary proliferation, liver fibrosis, and bicarbonate secretion. We evaluated the effectiveness of SR antagonist treatment for early-stage PBC. Male and female dominant-negative TGF-β receptor II (dnTGF-βRII) (model of PBC) and wild-type mice at 12 wk of age were treated with saline or the SR antagonist, Sec 5-27, for 1 wk. dnTGF-βRII mice expressed features of early-stage PBC along with enhanced Sct/SR axis activation and Sct secretion. dnTGF-βRII mice had increased biliary proliferation or senescence, inflammation, and liver fibrosis. In dnTGF-βRII mice, there was increased microRNA-125b/TGF-β1/TGF-β receptor 1/VEGF-A signaling. Human early-stage PBC patients had an increase in hepatobiliary Sct and SR expression and serum Sct levels. Increased biliary Sct/SR signaling promotes biliary and hepatic damage during early-stage PBC.-Kennedy, L., Francis, H., Invernizzi, P., Venter, J., Wu, N., Carbone, M., Gershwin, M. E., Bernuzzi, F., Franchitto, A., Alvaro, D., Marzioni, M., Onori, P., Gaudio, E., Sybenga, A., Fabris, L., Meng, F., Glaser, S., Alpini, G. Secretin/secretin receptor signaling mediates biliary damage and liver fibrosis in early-stage primary biliary cholangitis.

The tumour microenvironment and immune milieu of cholangiocarcinoma

Tumour microenvironment is a complex, multicellular functional compartment that, particularly when assembled as an abundant desmoplastic reaction, may profoundly affect the proliferative and invasive abilities of epithelial cancer cells. Tumour microenvironment comprises not only stromal cells, mainly cancer-associated fibroblasts, but also immune cells of both the innate and adaptive system (tumour-associated macrophages, neutrophils, natural killer cells, and T and B lymphocytes), and endothelial cells. This results in an intricate web of mutual communications regulated by an extensively remodelled extracellular matrix, where the tumour cells are centrally engaged. In this regard, cholangiocarcinoma, in particular the intrahepatic variant, has become the focus of mounting interest in the last years, largely because of the lack of effective therapies despite its rising incidence and high mortality rates worldwide. On the other hand, recent studies in pancreatic cancer, which similarly to cholangiocarcinoma, is highly desmoplastic, have argued against a tumour-promoting function of the tumour microenvironment. In this review, we will discuss recent developments concerning the role of each cellular population and their multifaceted interplay with the malignant biliary epithelial counterpart. We ultimately hope to provide the working knowledge on how their manipulation may lead to a therapeutic gain in cholangiocarcinoma.

Platelet-derived growth factor-D enables liver myofibroblasts to promote tumor lymphangiogenesis in cholangiocarcinoma

BACKGROUND & AIMS

In cholangiocarcinoma, early metastatic spread via lymphatic vessels often precludes curative therapies. Cholangiocarcinoma invasiveness is fostered by an extensive stromal reaction, enriched in cancer-associated fibroblasts (CAFs) and lymphatic endothelial cells (LECs). Cholangiocarcinoma cells recruit and activate CAFs by secreting PDGF-D. Herein, we investigated the role of PDGF-D and liver myofibroblasts in promoting lymphangiogenesis in cholangiocarcinoma.

METHODS

Human cholangiocarcinoma specimens were immunostained for podoplanin (LEC marker), α-SMA (CAF marker), VEGF-A, VEGF-C, and their cognate receptors (VEGFR2, VEGFR3). VEGF-A and VEGF-C secretion was evaluated in human fibroblasts obtained from primary sclerosing cholangitis explants. Using human LECs incubated with conditioned medium from PDGF-D-stimulated fibroblasts we assessed migration, 3D vascular assembly, transendothelial electric resistance and transendothelial migration of cholangiocarcinoma cells (EGI-1). We then studied the effects of selective CAF depletion induced by the BH3 mimetic navitoclax on LEC density and lymph node metastases in vivo.

RESULTS

In cholangiocarcinoma specimens, CAFs and LECs were closely adjacent. CAFs expressed VEGF-A and VEGF-C, while LECs expressed VEGFR2 and VEGFR3. Upon PDGF-D stimulation, fibroblasts secreted increased levels of VEGF-C and VEGF-A. Fibroblasts, stimulated by PDGF-D induced LEC recruitment and 3D assembly, increased LEC monolayer permeability, and promoted transendothelial EGI-1 migration. These effects were all suppressed by the PDGFRβ inhibitor, imatinib. In the rat model of cholangiocarcinoma, navitoclax-induced CAF depletion, markedly reduced lymphatic vascularization and reduced lymph node metastases.

CONCLUSION

PDGF-D stimulates VEGF-C and VEGF-A production by fibroblasts, resulting in expansion of the lymphatic vasculature and tumor cell intravasation. This critical process in the early metastasis of cholangiocarcinoma may be blocked by inducing CAF apoptosis or by inhibiting the PDGF-D-induced axis.

LAY SUMMARY

Cholangiocarcinoma is a highly malignant cancer affecting the biliary tree, which is characterized by a rich stromal reaction involving a dense population of cancer-associated fibroblasts that promote early metastatic spread. Herein, we show that cholangiocarcinoma-derived PDGF-D stimulates fibroblasts to secrete vascular growth factors. Thus, targeting fibroblasts or PDGF-D-induced signals may represent an effective tool to block tumor-associated lymphangiogenesis and reduce the invasiveness of cholangiocarcinoma.

Pinealectomy or light exposure exacerbates biliary damage and liver fibrosis in cholestatic rats through decreased melatonin synthesis

Melatonin, a neuroendocrine hormone synthesized by the pineal gland and cholangiocytes, decreases biliary hyperplasia and liver fibrosis during cholestasis-induced biliary injury via melatonin-dependent autocrine signaling through increased biliary arylalkylamine N-acetyltransferase (AANAT) expression and melatonin secretion, downregulation of miR-200b and specific circadian clock genes. Melatonin synthesis is decreased by pinealectomy (PINX) or chronic exposure to light. We evaluated the effect of PINX or prolonged light exposure on melatonin-dependent modulation of biliary damage/ductular reaction/liver fibrosis. Studies were performed in male rats with/without BDL for 1 week with 12:12 h dark/light cycles, continuous light or after 1 week of PINX. The expression of AANAT and melatonin levels in serum and cholangiocyte supernatant were increased in BDL rats, while decreased in BDL rats following PINX or continuous light exposure. BDL-induced increase in serum chemistry, ductular reaction, liver fibrosis, inflammation, angiogenesis and ROS generation were significantly enhanced by PINX or light exposure. Concomitant with enhanced liver fibrosis, we observed increased biliary senescence and enhanced clock genes and miR-200b expression in total liver and cholangiocytes. In vitro, the expression of AANAT, clock genes and miR-200b was increased in PSC human cholangiocyte cell lines (hPSCL). The proliferation and activation of HHStecs (human hepatic stellate cell lines) were increased after stimulating with BDL cholangiocyte supernatant and further enhanced when stimulated with BDL rats following PINX or continuous light exposure cholangiocyte supernatant via intracellular ROS generation. Conclusion: Melatonin plays an important role in the protection of liver against cholestasis-induced damage and ductular reaction.

Endo-laparoscopic reconstruction of the abdominal wall midline with linear stapler, the THT technique. Early results of the first case series

Background

Midline primary hernias represent one of the most frequent abdominal wall defects in the adult population and in almost half of the cases they are associated with a rectus abdominis diastasis (RAD). Despite the high incidence of these defects there is currently no consensus in the literature on what is the preferred surgical technique for treatment. In this paper we present the first case series treated with an innovative technique that aims to repair the defects of the midline and RAD, while combining the advantages of the sublay Rives-Stoppa technique with those of the minimally-invasive surgery.

Methods

Between January 2018 and May 2018, 14 patients underwent endo-laparoscopic reconstruction of the midline. The surgery was performed under general anaesthesia through a 4 cm periumbilical incision with single port technique. The rectus abdominis sheaths were joined together and sutured lengthwise using a linear stapler. A tailor-made synthetic prosthesis was positioned in the retromuscular space.

Results

All cases had RAD with a mean width of 5.3 cm in the supraumbilical space. None of the surgeries needed laparotomic conversion. The average duration of the surgery was 80 min. The hospitalization was in all cases one day. The average follow-up period was 6 months. Neither recurrences, nor major or minor complications have been reported to date.

Conclusion

Our THT is a feasible technique, easily reproducible, and effective in the repair of primary defects of the midline and RAD, which greatly reduces the operating times and hospitalization allowing a quick return to active life.

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The THT procedure is a surgical technique for repair of the abdominal wall midline hernias and rectus abdominis diastasis.

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The THT procedure combines the advantages of endoscopic single port surgery with those of a retromuscular prosthetic reconstruction.

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The THT procedure strongly reduces costs and operative times if compared to lap/robotic surgery while allows to avoid the complication risks related to a large laparotomy.

Liver diseases in the dish: iPSC and organoids as a new approach to modeling liver diseases

Liver diseases negatively impact the quality of life and survival of patients, and often require liver transplantation in cases that progress to organ failure. Understanding the cellular and molecular mechanisms of liver development and pathogenesis has been a challenging task, in part for the lack of adequate cellular models directly relevant to the human diseases. Recent technological advances in the stem cell field have shown the potentiality of induced pluripotent stem cells (iPSC) and liver organoids as the next generation tool to model in vitro liver diseases. Hepatocyte-like cells and cholangiocyte are currently being generated from skin fibroblasts and mononuclear blood cells reprogrammed into iPSC and have been successfully used for disease modeling, drug testing and gene editing, with the hope to be able to find application also in regenerative medicine. Protocols to generate other liver cell types are still under development, but the field is advancing rapidly. On the other end, liver cells can now be isolated from liver specimens (liver explants or liver biopsies) and cultured in specific conditions to form polarized 3D organoids. The purpose of this review is to summarize all these recent technological advances and their potential applications but also to analyze the current issues to be addressed before the technology can reach its full potential.

Animal models of cholestasis: An update on inflammatory cholangiopathies

Cholestasis is a frequent clinical condition initiating or complicating chronic liver diseases, particularly cholangiopathies, where the biliary epithelium is the primary target of the pathogenetic sequence. Until a few decades ago, understanding of cholestasis relied mostly on the experimental model of bile duct ligation in rodents. However, a simple model of biliary obstruction cannot reproduce the complex mechanisms and networks leading to cholestasis in cholangiopathies. These networks are underpinned by an intricate dysregulation of pro-inflammatory and pro-fibrotic signals involving besides cholangiocytes, multiple cell elements of both innate and adaptive immunity. Therefore, in the last years, a wide range of animal models of biliary injury have been developed, mostly in mice, following three main approaches, chemical induction, immunization and genetic manipulation. In this review, we will give an update of the animal models of the two main cholangiopathies, primary sclerosing cholangitis and primary biliary cholangitis, which have provided us with the most relevant insights into the pathogenesis of these still controversial diseases.

Animal models for cystic fibrosis liver disease (CFLD)

Liver disease is a severe complication in patients with Cystic Fibrosis (CF), a genetic disease caused by mutations in the gene encoding for cystic fibrosis transmembrane conductance regulator (CFTR) channel. The sequence of events leading to CFLD is still unclear and has limited the development of more specific treatments other than the bile acid UDCA. However, in the last twenty years, several gaps have been filled, which have mainly been possible due to the availability of different animal models that mimic CF. CF mice, although they lack a spontaneous liver manifestation, have been essential to better understand the multiple functions of CFTR expression on the apical membrane of cholangiocytes, from chloride channel to regulator of epithelial innate immunity. Additionally, we have learned that the gut microbiota might be a pathogenetic factor for the development of liver disease. The recent creation of novel CF animal models (i.e. pig and ferret) that better reproduce the human disease, will allow for comparative studies with species that spontaneously develop the liver disease and will hopefully lead to novel therapeutic treatments. In this review, we have compared and summarized the main features of the current available CF animal models and their applicability for the study of the liver phenotype.

Precision medicine in cholangiocarcinoma

Cholangiocarcinoma is one of the epithelial cancers with the poorest prognosis and the narrowest therapeutic choice in humans. Compared with other cancer types, cholangiocarcinoma has been often neglected by oncology and liver research studies, thereby leaving many issues unsolved. Apart from the early and marked aggressiveness, one of the main reasons of the still unsatisfying clinical management of cholangiocarcinoma is its wide tumor heterogeneity needing more than other diseases a 'precision medicine' approach. In this regard, in the last few years there has been an awakening of interest aimed at dissecting the complex molecular and genomic profile of cholangiocarcinoma. Thus, a range of molecular players have been recently identified as putative mechanistic determinants of cholangiocarcinoma invasiveness, encompassing tyrosine kinase receptors, metabolic enzymes, transcription factors, small GTPases, ubiquitin ligases, and chromatin-remodelling proteins, whose aberrant expression may derive from stochastic mutations as well as from pro-oncogenic paracrine signals released by the stromal microenvironment, which is particularly exuberant in cholangiocarcinoma. Herein, we sought to overview the most relevant observations unravelling the genomic landscape of cholangiocarcinoma, and the prognostic and predictive biomarkers that consequently have been emerging. Then, we will discuss innovative treatment approaches derived from conventional chemotherapy, targeted therapies, antiangiogenic therapies and immunotherapy, and how they are opening new avenues towards a precision medicine in cholangiocarcinoma.

β-Catenin and interleukin-1β-dependent chemokine (C-X-C motif) ligand 10 production drives progression of disease in a mouse model of congenital hepatic fibrosis

Congenital hepatic fibrosis (CHF), a genetic disease caused by mutations in the polycystic kidney and hepatic disease 1 (PKHD1) gene, encoding for the protein fibrocystin/polyductin complex, is characterized by biliary dysgenesis, progressive portal fibrosis, and a protein kinase A-mediated activating phosphorylation of β-catenin at Ser675. Biliary structures of Pkhd1^del4/del4 mice, a mouse model of CHF, secrete chemokine (C-X-C motif) ligand 10 (CXCL10), a chemokine able to recruit macrophages. The aim of this study was to clarify whether CXCL10 plays a pathogenetic role in disease progression in CHF/Caroli disease and to understand the mechanisms leading to increased CXCL10 secretion. We demonstrate that treatment of Pkhd1^del4/del4 mice for 3 months with AMG-487, an inhibitor of CXC chemokine receptor family 3, the cognate receptor of CXCL10, reduces the peribiliary recruitment of alternative activated macrophages (cluster of differentiation 45⁺ F4/80⁺ cells), spleen size, liver fibrosis (sirius red), and cyst growth (cytokeratin 19-positive area), consistent with a pathogenetic role of CXCL10. Furthermore, we show that in fibrocystin/polyductin complex-defective cholangiocytes, isolated from Pkhd1^del4/del4 mice, CXCL10 production is mediated by Janus kinase/signal transducer and activator of transcription 3 in response to interleukin 1beta (IL-1β) and β-catenin. Specifically, IL-1β promotes signal transducer and activator of transcription 3 phosphorylation, whereas β-catenin promotes its nuclear translocation. Increased pro-IL-1β was regulated by nuclear factor kappa-light-chain-enhancer of activated B cells, and increased secretion of active IL-1β was mediated by the activation of Nod-like receptors, pyrin domain containing 3 inflammasome (increased expression of caspase 1 and Nod-like receptors, pyrin domain containing 3).

CONCLUSION

In fibrocystin/polyductin complex-defective cholangiocytes, β-catenin and IL-1β are responsible for signal transducer and activator of transcription 3-dependent secretion of CXCL10; in vivo experiments show that the CXCL10/CXC chemokine receptor family 3 axis prevents the recruitment of macrophages, reduces inflammation, and halts the progression of the disease; the increased production of IL-1β highlights the autoinflammatory nature of CHF and may open novel therapeutic avenues. (Hepatology 2018;67:1903-1919).

Molecular Mechanisms Driving Cholangiocarcinoma Invasiveness: An Overview

The acquisition of invasive functions by tumor cells is a first and crucial step toward the development of metastasis, which nowadays represents the main cause of cancer-related death. Cholangiocarcinoma (CCA), a primary liver cancer originating from the biliary epithelium, typically develops intrahepatic or lymph node metastases at early stages, thus preventing the majority of patients from undergoing curative treatments, consistent with their very poor prognosis. As in most carcinomas, CCA cells gradually adopt a motile, mesenchymal-like phenotype, enabling them to cross the basement membrane, detach from the primary tumor, and invade the surrounding stroma. Unfortunately, little is known about the molecular mechanisms that synergistically orchestrate this proinvasive phenotypic switch. Autocrine and paracrine signals (cyto/chemokines, growth factors, and morphogens) permeating the tumor microenvironment undoubtedly play a prominent role in this context. Moreover, a number of recently identified signaling systems are currently drawing attention as putative mechanistic determinants of CCA cell invasion. They encompass transcription factors, protein kinases and phosphatases, ubiquitin ligases, adaptor proteins, and miRNAs, whose aberrant expression may result from either stochastic mutations or the abnormal activation of upstream pro-oncogenic pathways. Herein we sought to summarize the most relevant molecules in this field and to discuss their mechanism of action and potential prognostic relevance in CCA. Hopefully, a deeper knowledge of the molecular determinants of CCA invasiveness will help to identify clinically useful biomarkers and novel druggable targets, with the ultimate goal to develop innovative approaches to the management of this devastating malignancy.

Src kinase inhibition reduces inflammatory and cytoskeletal changes in ΔF508 human cholangiocytes and improves cystic fibrosis transmembrane conductance regulator correctors efficacy

Cystic fibrosis transmembrane conductance regulator (CFTR), the channel mutated in cystic fibrosis (CF), is expressed by the biliary epithelium (i.e., cholangiocytes) of the liver. Progressive clinical liver disease (CF-associated liver disease; CFLD) occurs in around 10% of CF patients and represents the third leading cause of death. Impaired secretion and inflammation contribute to CFLD; however, the lack of human-derived experimental models has hampered the understanding of CFLD pathophysiology and the search for a cure. We have investigated the cellular mechanisms altered in human CF cholangiocytes using induced pluripotent stem cells (iPSCs) derived from healthy controls and a ΔF508 CFTR patient. We have devised a novel protocol for the differentiation of human iPSC into polarized monolayers of cholangiocytes. Our results show that iPSC-cholangiocytes reproduced the polarity and the secretory function of the biliary epithelium. Protein kinase A/cAMP-mediated fluid secretion was impaired in ΔF508 cholangiocytes and negligibly improved by VX-770 and VX-809, two small molecule drugs used to correct and potentiate ΔF508 CFTR. Moreover, ΔF508 cholangiocytes showed increased phosphorylation of Src kinase and Toll-like receptor 4 and proinflammatory changes, including increased nuclear factor kappa-light-chain-enhancer of activated B cells activation, secretion of proinflammatory chemokines (i.e., monocyte chemotactic protein 1 and interleukin-8), as well as alterations of the F-actin cytoskeleton. Treatment with Src inhibitor (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyramidine) decreased the inflammatory changes and improved cytoskeletal defects. Inhibition of Src, along with administration of VX-770 and VX-809, successfully restored fluid secretion to normal levels.

CONCLUSION

Our findings have strong translational potential and indicate that targeting Src kinase and decreasing inflammation may increase the efficacy of pharmacological therapies aimed at correcting the basic ΔF508 defect in CF liver patients. These studies also demonstrate the promise of applying iPSC technology in modeling human cholangiopathies. (Hepatology 2018;67:972-988).

Hydraulic modelling of the spatial and temporal variability in Atlantic salmon parr habitat availability in an upland stream

We show how spatial variability in channel bed morphology affects the hydraulic characteristics of river reaches available to Atlantic salmon parr (Salmo salar) under different flow conditions in an upland stream. The study stream, the Girnock Burn, is a long-term monitoring site in the Scottish Highlands. Six site characterised by different bed geometry and morphology were investigated. Detailed site bathymetries were collected and combined with discharge time series in a 2D hydraulic model to obtain spatially distributed depth-averaged velocities under different flow conditions. Available habitat (AH) was estimated for each site. Stream discharge was used according to the critical displacement velocity (CDV) approach. CDV defines a velocity threshold above which salmon parr are not able to hold station and effective feeding opportunities or habitat utilization are reduced, depending on fish size and water temperature. An average value of the relative available habitat (<RAH>) for the most significant period for parr growth - April to May - was used for inter-site comparison and to analyse temporal variations over 40years. Results show that some sites are more able than others to maintain zones where salmon parr can forage unimpeded by high flow velocities under both wet and dry conditions. With lower flow velocities, dry years offer higher values of <RAH> than wet years. Even though <RAH> can change considerably across the sites as stream flow changes, the directions of change are consistent. Relative available habitat (RAH) shows a strong relationship with discharge per unit width, whilst channel slope and bed roughness either do not have relevant impact or compensate each other. The results show that significant parr habitat was available at all sites across all flows during this critical growth period, suggesting that hydrological variability is not a factor limiting growth in the Girnock.