Dual roles of B lymphocytes in mouse models of diet-induced nonalcoholic fatty liver disease.

BACKGROUND AND AIMS: Growing evidence suggests an important role of B cells in the development of NAFLD. However, a detailed functional analysis of B cell subsets in NAFLD pathogenesis is lacking. APPROACH AND RESULTS: In wild-type mice, 21 weeks of high fat diet (HFD) feeding resulted in NAFLD with massive macrovesicular steatosis, modest hepatic and adipose tissue inflammation, insulin resistance, and incipient fibrosis. Remarkably, Bnull (JHT) mice were partially protected whereas B cell harboring but antibody-deficient IgMi mice were completely protected from the development of hepatic steatosis, inflammation, and fibrosis. The common feature of JHT and IgMi mice is that they do not secrete antibodies, whereas HFD feeding in wild-type mice led to increased levels of serum IgG2c. Whereas JHT mice have no B cells at all, regulatory B cells were found in the liver of both wild-type and IgMi mice. HFD reduced the number of regulatory B cells and IL-10 production in the liver of wild-type mice, whereas these increased in IgMi mice. Livers of patients with advanced liver fibrosis showed abundant deposition of IgG and stromal B cells and low numbers of IL-10 expressing cells, compatible with our experimental data. CONCLUSIONS: B lymphocytes have both detrimental and protective effects in HFD-induced NAFLD. The lack of secreted pathogenic antibodies protects partially from NAFLD, whereas the presence of certain B cell subsets provides additional protection. IL-10-producing regulatory B cells may represent such a protective B cell subset.

A structurally engineered fatty acid, icosabutate, suppresses liver inflammation and fibrosis in NASH.

BACKGROUND & AIMS: Although long-chain omega-3 fatty acids (LCn-3FAs) regulate inflammatory pathways of relevance to non-alcoholic steatohepatitis (NASH), their susceptibility to peroxidation may limit their therapeutic potential. We compared the metabolism of eicosapentaenoic acid (EPA) with an engineered EPA derivative (icosabutate) in human hepatocytes in vitro and their effects on hepatic glutathione metabolism, oxidised lipids, inflammation, and fibrosis in a dietary mouse model of NASH, and in patients prone to fatty liver disease. METHODS: Oxidation rates and cellular partitioning of EPA and icosabutate were compared in primary human hepatocytes. Comparative effects of delayed treatment with either low- (56 mg/kg) or high-dose (112 mg/kg) icosabutate were compared with EPA (91 mg/kg) or a glucagon-like peptide 1 receptor agonist in a choline-deficient (CD), L-amino acid-defined NASH mouse model. To assess the translational potential of these findings, effects on elevated liver enzymes and fibrosis-4 (FIB-4) score were assessed in overweight, hyperlipidaemic patients at an increased risk of NASH. RESULTS: In contrast to EPA, icosabutate resisted oxidation and incorporation into hepatocytes. Icosabutate also reduced inflammation and fibrosis in conjunction with a reversal of CD diet-induced changes in the hepatic lipidome. EPA had minimal effect on any parameter and even worsened fibrosis in association with depletion of hepatic glutathione. In dyslipidaemic patients at risk of NASH, icosabutate rapidly normalised elevated plasma ALT, GGT and AST and reduced FIB-4 in patients with elevated ALT and/or AST. CONCLUSION: Icosabutate does not accumulate in hepatocytes and confers beneficial effects on hepatic oxidative stress, inflammation and fibrosis in mice. In conjunction with reductions in markers of liver injury in hyperlipidaemic patients, these findings suggest that structural engineering of LCn-3FAs offers a novel approach for the treatment of NASH. LAY SUMMARY: Long-chain omega-3 fatty acids are involved in multiple pathways regulating hepatic inflammation and fibrosis, but their susceptibility to peroxidation and use as an energy source may limit their clinical efficacy. Herein, we show that a structurally modified omega-3 fatty acid, icosabutate, overcame these challenges and had markedly improved antifibrotic efficacy in a mouse model of non-alcoholic steatohepatitis. A hepatoprotective effect of icosabutate was also observed in patients with elevated circulating lipids, in whom it led to rapid reductions in markers of liver injury.

Suicide rate and social environment characteristics in South Korea: the roles of socioeconomic, demographic, urbanicity, general health behaviors, and other environmental factors on suicide rate.

BACKGROUND: Suicide is a serious worldwide public health concern, and South Korea has shown the highest suicide rate among Organisation for Economic Co-operation and Development (OECD) countries since 2003. Nevertheless, most previous Korean studies on suicide had limitations in investigating various social environment factors using long-term nationwide data. Thus, this study examined how various social environment characteristics are related to the suicide rate at the district-level, using nationwide longitudinal data over 11 years. METHODS: We used the district-level age-standardized suicide rate and a total of 12 annual social environment characteristics that represented socioeconomic, demographic, urbanicity, general health behaviors, and other environmental characteristics from 229 administrative districts in South Korea. A Bayesian hierarchical model with integrated Laplace approximations (INLA) was used to examine the spatiotemporal association between the rate of suicide and the social environment indicators selected for the study. RESULTS: In the total population, the indicators "% of population aged 65 and older eligible for the basic pension", "% vacant houses in the area", "% divorce", "% single elderly households", "% detached houses", "% current smokers", and "% of population with obesity" showed positive associations with the suicide rate. In contrast, "% of people who regularly participated in religious activities" showed negative associations with suicide rate. The associations between these social environment characteristics and suicide rate were generally more statistically significant in males and more urbanized areas, than in females and less urbanized areas; however, associations differed amongst age groups, depending on the social environment characteristic variable under study. CONCLUSIONS: This study investigated the complex role of social environments on suicide rate in South Korea and revealed that higher suicide rates were associated with lower values of socioeconomic status, physical exercise, and religious activities, and with higher social isolation and smoking practice. Our results can be used in the development of targeted suicide prevention policies.

3D analysis of microvasculature in murine liver fibrosis models using synchrotron radiation-based microtomography.

Cirrhosis describes the development of excess fibrous tissue around regenerative nodules in response to chronic liver injury and usually leads to irreversible organ damage and end-stage liver disease. During the development of cirrhosis, the formation of collagenous scar tissue is paralleled by a reorganization and remodeling of the hepatic vascular system. To date, macrovascular remodeling in various cirrhosis models has been examined using three-dimensional (3D) imaging modalities, while microvascular changes have been studied mainly by two-dimensional (2D) light microscopic and electron microscopic imaging. Here, we report on the application of high-resolution 3D synchrotron radiation-based microtomography (SRµCT) for the study of the sinusoidal and capillary blood vessel system in three murine models of advanced parenchymal and biliary hepatic fibrosis. SRµCT facilitates the characterization of microvascular architecture and identifies features of intussusceptive angiogenesis in progressive liver fibrosis in a non-destructive 3D manner.

Huge Anterior Skull Base Defect Reconstruction on Communicating Between Cranium and Nasal Cavity: Combination Flap of Galeal Flap and Reverse Temporalis Flap.

INTRODUCTION: Traditionally, galeal flap or cranialization was often used to reconstruct the skull base defect caused by trauma or tumor removal. However, in the case of huge skull base defect, galeal flap is not enough to block the communication between nasal cavity and intracranial space. In this study, authors suggest combination flap of galea and reverse temporalis muscle as a method for reconstruction of huge skull base defect. MATERIALS AND METHODS: From 2016 to 2019, retrospective review was conducted, assessing 7 patients with bone defect which is not just opening of frontal sinus but extends to frontal sinus and cribriform plate. Reconstructions were done by combination of galeal flap and reverse temporalis muscle flap transposition. RESULTS: Defects were caused by nasal cavity tumor with intracranial extension or brain tumor with nasal cavity extension. There was no major complication in every case. During the follow up period, no patient had signs of complication such as ascending infection, herniation and CSF rhinorrhea. Postoperative radiologic images of all patients that were taken at least 6 months after the surgery showed that flaps maintained the lining and the volume well. DISCUSSION: Conventional reconstruction of skull base defect with galeal flap is not effective enough to cover the large sized defect. In conclusion, galeal flap in combination with reverse temporalis muscle flap can effectively block the communication of nasal cavity and intracranium.

Deletion of organic cation transporter Oct3 promotes hepatic fibrosis via upregulation of TGFß.

Organic cation transporters (OCT) are responsible for the intracellular uptake and detoxification of a broad spectrum of endogenous and exogenous substrates. OCTs are downregulated in cholestasis, fibrosis, and hepatocellular carcinoma, but the underlying molecular mechanisms and downstream effects of OCT deletion are unknown. Oct3-knockout (Oct3-/-; FVB.Slc22a3tm10pb) and wild-type (WT; FVB) mice were subject to escalating doses of carbon tetrachloride (CCl4) or thioacetamide (TAA) for 6 wk to induce advanced parenchymal liver fibrosis. Secondary biliary fibrosis was generated by bile duct ligation. Liver fibrosis was assessed by hydroxyproline determination, quantitative Sirius red morphometry, and quantitative real-time PCR for fibrosis and inflammation-related genes. Ductular reaction was assessed by bile duct count per field of view in hematoxylin and eosin staining. General gene expression analyses were performed in liver tissue from untreated Oct3-/- and WT mice. Finally, primary murine hepatocytes were treated with the nonselective OCT inhibitor quinine, and transforming growth factor-ß1 (Tgfß1) protein expression was quantified by quantitative real-time PCR and Western blot. Oct3-/- mice developed significantly more fibrosis after bile duct ligation and CCl4 treatment compared with WT mice. Ductular reaction was enhanced in the long-term model. Concomitantly, Oct1 mRNA expression was downregulated during cholestatic and chemically (TAA and CCl4) induced fibrogenesis. The downregulation of Oct1 mRNA in fibrotic liver tissue reversed within 4 wk after TAA cessation. Gene expression analysis by next-generation sequencing revealed an enrichment of Tgfß1 target genes in Oct3-/- mice. Tgfß1 mRNA expression was significantly upregulated after chemically induced fibrosis (P < 0.001) in Oct3-/- compared with WT mice. Accordingly, in primary murine hepatocytes functional inhibition of OCT led to an upregulation of Tgfß1 mRNA expression. Loss of Oct3 promotes fibrogenesis by affecting Tgfß-mediated homeostasis in mice with chronic biliary and parenchymal liver damage and fibrosis.NEW & NOTEWORTHY We show for the first time that organic cation transporter 3 (Oct3) is not only downregulated in fibrosis but loss of Oct3 also leads to an upregulation of transforming growth factor-ß contributing to fibrosis progression.

Effects of nintedanib on the microvascular architecture in a lung fibrosis model.

Nintedanib, a tyrosine kinase inhibitor approved for the treatment of idiopathic pulmonary fibrosis, has anti-fibrotic, anti-inflammatory, and anti-angiogenic activity. We explored the impact of nintedanib on microvascular architecture in a pulmonary fibrosis model. Lung fibrosis was induced in C57Bl/6 mice by intratracheal bleomycin (0.5 mg/kg). Nintedanib was started after the onset of lung pathology (50 mg/kg twice daily, orally). Micro-computed tomography was performed via volumetric assessment. Static lung compliance and forced vital capacity were determined by invasive measurements. Mice were subjected to bronchoalveolar lavage and histologic analyses, or perfused with a casting resin. Microvascular corrosion casts were imaged by scanning electron microscopy and synchrotron radiation tomographic microscopy, and quantified morphometrically. Bleomycin administration resulted in a significant increase in higher-density areas in the lungs detected by micro-computed tomography, which was significantly attenuated by nintedanib. Nintedanib significantly reduced lung fibrosis and vascular proliferation, normalized the distorted microvascular architecture, and was associated with a trend toward improvement in lung function and inflammation. Nintedanib resulted in a prominent improvement in pulmonary microvascular architecture, which outperformed the effect of nintedanib on lung function and inflammation. These findings uncover a potential new mode of action of nintedanib that may contribute to its efficacy in idiopathic pulmonary fibrosis.

Comparison of Gene Expression Patterns Between Mouse Models of Nonalcoholic Fatty Liver Disease and Liver Tissues From Patients.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries. Mouse models of NAFLD have been used in studies of pathogenesis and treatment, and have certain features of the human disease. We performed a systematic transcriptome-wide analysis of liver tissues from patients at different stages of NAFLD progression (ranging from healthy obese individuals to those with steatosis), as well as rodent models of NAFLD, to identify those that most closely resemble human disease progression in terms of gene expression patterns. METHODS: We performed a systematic evaluation of genome-wide messenger RNA expression using liver tissues collected from mice fed a standard chow diet (controls) and 9 mouse models of NAFLD: mice on a high-fat diet (with or without fructose), mice on a Western-type diet, mice on a methionine- and choline-deficient diet, mice on a high-fat diet given streptozotocin, and mice with disruption of Pten in hepatocytes. We compared gene expression patterns with those of liver tissues from 25 patients with nonalcoholic steatohepatitis (NASH), 27 patients with NAFLD, 15 healthy obese individuals, and 39 healthy nonobese individuals (controls). Liver samples were obtained from patients undergoing liver biopsy for suspected NAFLD or NASH, or during liver or bariatric surgeries. Data sets were analyzed using the limma R-package. Overlap of functional profiles was analyzed by gene set enrichment analysis profiles. RESULTS: We found differences between human and mouse transcriptomes to be significantly larger than differences between disease stages or models. Of the 65 genes with significantly altered expression in patients with NASH and 177 genes with significantly altered expression in patients with NAFLD, compared with controls, only 1-18 of these genes also differed significantly in expression between mouse models of NAFLD and control mice. However, expression of genes that regulate pathways associated with the development of NAFLD were altered in some mouse models (such as pathways associated with lipid metabolism). On a pathway level, gene expression patterns in livers of mice on the high-fat diet were associated more closely with human fatty liver disease than other models. CONCLUSIONS: In comparing gene expression profiles between liver tissues from different mouse models of NAFLD and patients with different stages of NAFLD, we found very little overlap. Our data set is available for studies of pathways that contribute to the development of NASH and NAFLD and selection of the most applicable mouse models (http://www.nash-profiler.com).

Hepatic B cell leukemia-3 promotes hepatic steatosis and inflammation through insulin-sensitive metabolic transcription factors.

BACKGROUND & AIMS: The pathomechanisms underlying non-alcoholic fatty liver disease (NAFLD) and the involved molecular regulators are incompletely explored. The nuclear factor-kappa B (NF-κB)-cofactor gene B cell leukemia-3 (Bcl-3) plays a critical role in altering the transcriptional capacity of NF-κB - a key inducer of inflammation - but also of genes involved in cellular energy metabolism. METHODS: To define the role of Bcl-3 in non-alcoholic steatohepatitis (NASH), we developed a novel transgenic mouse model with hepatocyte-specific overexpression of Bcl-3 (Bcl-3Hep) and employed a high-fat, high-carbohydrate dietary feeding model. To characterize the transgenic model, deep RNA sequencing was performed. The relevance of the findings was confirmed in human liver samples. RESULTS: Hepatocyte-specific overexpression of Bcl-3 led to pronounced metabolic derangement, characterized by enhanced hepatic steatosis from increased de novo lipogenesis and uptake, as well as decreased hydrolysis and export of fatty acids. Steatosis in Bcl-3Hep mice was accompanied by an augmented inflammatory milieu and liver cell injury. Moreover, Bcl-3 expression decreased insulin sensitivity and resulted in compensatory regulation of insulin-signaling pathways. Based on in vivo and in vitro studies we identified the transcription factors PPARα, PPARγ and PGC-1α as critical regulators of hepatic metabolism and inflammation downstream of Bcl-3. Metformin treatment improved the metabolic and inflammatory phenotype in Bcl-3Hep mice through modulation of PPARα and PGC-1α. Remarkably, these findings were recapitulated in human NASH, which exhibited increased expression and nuclear localization of Bcl-3. CONCLUSIONS: In summary, Bcl-3 emerges as a novel regulator of hepatic steatosis, insulin sensitivity and inflammation in NASH. LAY SUMMARY: Non-alcoholic fatty liver disease (NAFLD) is considered the most prevalent liver disease worldwide. Patients can develop end-stage liver disease resulting in liver cirrhosis or hepatocellular carcinoma, but also develop complications unrelated to liver disease, e.g., cardiovascular disease. Still there is no full understanding of the mechanisms that cause NAFLD. In this study, genetically engineered mice were employed to examine the role of a specific protein in the liver that is involved in inflammation and the metabolism, namely Bcl-3. By this approach, a better understanding of the mechanisms contributing to disease progression was established. This can help to develop novel therapeutic and diagnostic options for patients with NAFLD.

Podoplanin discriminates distinct stromal cell populations and a novel progenitor subset in the liver.

Podoplanin/gp38(+) stromal cells present in lymphoid organs play a central role in the formation and reorganization of the extracellular matrix and in the functional regulation of immune responses. Gp38(+) cells are present during embryogenesis and in human livers of primary biliary cirrhosis. Since little is known about their function, we studied gp38(+) cells during chronic liver inflammation in models of biliary and parenchymal liver fibrosis and steatohepatitis. Gp38(+) cells were analyzed using flow cytometry and confocal microscopy, and the expression of their steady state and inflammation-associated genes was evaluated from healthy and inflamed livers. Gp38(+) cells significantly expanded in all three models of liver injury and returned to baseline levels during regression of inflammation. Based on CD133 and gp38 expression in the CD45(-)CD31(-)Asgpr1(-) liver cell fraction, numerous subsets could be identified that were negative for CD133 (gp38(hi)CD133(-), gp38(low)CD133(-), and gp38(-)CD133(-)). Moreover, among the CD133(+) cells, previously identified as progenitor population in injured liver, two subpopulations could be distinguished based on their gp38 expression (gp38(-)CD133(+) and CD133(+)gp38(+)). Importantly, the distribution of the identified subsets in inflammation illustrated injury-specific changes. Moreover, the gp38(+)CD133(+) cells exhibited liver progenitor cell characteristics similar to the gp38(-)CD133(+) population, thus representing a novel subset within the classical progenitor cell niche. Additionally, these cells expressed distinct sets of inflammatory genes during liver injury. Our study illuminates a novel classification of the stromal/progenitor cell compartment in the liver and pinpoints a hitherto unrecognized injury-related alteration in progenitor subset composition in chronic liver inflammation and fibrosis.

Specific hepatic delivery of procollagen α1(I) small interfering RNA in lipid-like nanoparticles resolves liver fibrosis.

UNLABELLED: Fibrosis accompanies the wound-healing response to chronic liver injury and is characterized by excessive hepatic collagen accumulation dominated by collagen type I. Fibrosis often progresses to cirrhosis. Here we present in vivo evidence of an up to 90% suppression of procollagen α1(I) expression, a reduction of septa formation, and a 40%-60% decrease of collagen deposition in mice with progressive and advanced liver fibrosis that received cationic lipid nanoparticles loaded with small interfering RNA to the procollagen α1(I) gene. After intravenous injection, up to 90% of lipid nanoparticles loaded with small interfering RNA to the procollagen α1(I) gene were retained in the liver of fibrotic mice and accumulated in nonparenchymal more than parenchymal cells for prolonged periods, significantly ameliorating progression and accelerating regression of fibrosis. CONCLUSION: Our lipid nanoparticles loaded with small interfering RNA to the procollagen α1(I) gene specifically reduce total hepatic collagen content without detectable side effects, potentially qualifying as a therapy for fibrotic liver diseases.

Extrahepatic platelet-derived growth factor-ß, delivered by platelets, promotes activation of hepatic stellate cells and biliary fibrosis in mice.

BACKGROUND & AIMS: Platelet-derived growth factor-ß (PDGFB) is a mitogen for hepatic stellate cells (HSCs). We studied the cellular sources of PDGFB and the effects of a high-affinity monoclonal antibody against PDGFB (MOR8457) in mouse models of biliary fibrosis. METHODS: Cellular sources of PDGFB were identified using quantitative reverse-transcription polymerase chain reaction, biochemical, and immunohistologic methods. Mice with advanced biliary fibrosis, MDR2(Abcb4)-null mice, and C57Bl/6 (control) mice were placed on 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-supplemented diets and were given weekly intraperitoneal injections of MOR8457. Platelets were depleted from MDR2-null mice by injection of an antibody against CD41, or inhibited with diets containing low-dose aspirin. Liver tissues were collected and analyzed by quantitative reverse-transcription PCR and histologic and biochemical analyses. RESULTS: Levels of PDGFB protein, but not messenger RNA, were increased in fibrotic livers of MDR2-null mice, compared with control mice. Platelet clusters were detected in the hepatic endothelium, in close proximity to HSCs, and were identified as a source of PDGFB protein in MDR2-null mice. Levels of the PDGFB were increased in serum samples from patients with early stages of liver fibrosis of various etiologies (F1-2, n = 16; P < .05), compared with nonfibrotic liver tissue (F0, n = 12). Depletion of platelets from MDR2-null mice normalized hepatic levels of PDGFB within 48 hours, reducing levels of a marker of HSC activation (α-smooth muscle actin) and expression of genes that promote fibrosis. Diets supplemented with low-dose aspirin reduced circulating serum and hepatic levels of PDGFB and significantly reduced progression of fibrosis in MDR2-null mice over 1 year. MOR8457 produced a dose-dependent decrease in liver fibrosis in MDR2-null mice, reducing collagen deposition by 45% and expression of fibrosis-associated genes by 50%, compared with mice given a control antibody. In vitro, platelets activated freshly isolated HSCs (induction of α-smooth muscle actin and fibrosis-associated genes) via a PDGFB-dependent mechanism. MOR8457 also reduced liver fibrosis in mice placed on DDC-supplemented diets. CONCLUSIONS: Platelets produce PDGFB to activate HSC and promote fibrosis in MDR2-null mice and mice on DDC-supplemented diets. Antiplatelet therapy or selective inhibition of PDGFB might reduce biliary fibrosis in patients with liver disease.

An unbiased ranking of murine dietary models based on their proximity to human metabolic dysfunction-associated steatotic liver disease (MASLD).

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease, encompasses steatosis and metabolic dysfunction-associated steatohepatitis (MASH), leading to cirrhosis and hepatocellular carcinoma. Preclinical MASLD research is mainly performed in rodents; however, the model that best recapitulates human disease is yet to be defined. We conducted a wide-ranging retrospective review (metabolic phenotype, liver histopathology, transcriptome benchmarked against humans) of murine models (mostly male) and ranked them using an unbiased MASLD 'human proximity score' to define their metabolic relevance and ability to induce MASH-fibrosis. Here, we show that Western diets align closely with human MASH; high cholesterol content, extended study duration and/or genetic manipulation of disease-promoting pathways are required to intensify liver damage and accelerate significant (F2+) fibrosis development. Choline-deficient models rapidly induce MASH-fibrosis while showing relatively poor translatability. Our ranking of commonly used MASLD models, based on their proximity to human MASLD, helps with the selection of appropriate in vivo models to accelerate preclinical research.

Fibroblast Activation Protein Activates Macrophages and Promotes Parenchymal Liver Inflammation and Fibrosis.

BACKGROUND & AIMS: Fibroblast activation protein (FAP) is expressed on activated fibroblast. Its role in fibrosis and desmoplasia is controversial, and data on pharmacological FAP inhibition are lacking. We aimed to better define the role of FAP in liver fibrosis in vivo and in vitro. METHODS: FAP expression was analyzed in mice and patients with fibrotic liver diseases of various etiologies. Fibrotic mice received a specific FAP inhibitor (FAPi) at 2 doses orally for 2 weeks during parenchymal fibrosis progression (6 weeks of carbon tetrachloride) and regression (2 weeks off carbon tetrachloride), and with biliary fibrosis (Mdr2-/-). Recombinant FAP was added to (co-)cultures of hepatic stellate cells (HSC), fibroblasts, and macrophages. Fibrosis- and inflammation-related parameters were determined biochemically, by quantitative immunohistochemistry, polymerase chain reaction, and transcriptomics. RESULTS: FAP+ fibroblasts/HSCs were α-smooth muscle actin (α-SMA)-negative and located at interfaces of fibrotic septa next to macrophages in murine and human livers. In parenchymal fibrosis, FAPi reduced collagen area, liver collagen content, α-SMA+ myofibroblasts, M2-type macrophages, serum alanine transaminase and aspartate aminotransferase, key fibrogenesis-related transcripts, and increased hepatocyte proliferation 10-fold. During regression, FAP was suppressed, and FAPi was ineffective. FAPi less potently inhibited biliary fibrosis. In vitro, FAP small interfering RNA reduced HSC α-SMA expression and collagen production, and FAPi suppressed their activation and proliferation. Compared with untreated macrophages, FAPi regulated macrophage profibrogenic activation and transcriptome, and their conditioned medium attenuated HSC activation, which was increased with addition of recombinant FAP. CONCLUSIONS: Pharmacological FAP inhibition attenuates inflammation-predominant liver fibrosis. FAP is expressed on subsets of activated fibroblasts/HSC and promotes both macrophage and HSC profibrogenic activity in liver fibrosis.

Regulatory T-cell deficiency leads to features of autoimmune liver disease overlap syndrome in scurfy mice.

Introduction: Scurfy mice have a complete deficiency of functional regulatory T cells (Treg) due to a frameshift mutation in the Foxp3 gene. The impaired immune homeostasis results in a lethal lymphoproliferative disorder affecting multiple organs, including the liver. The autoimmune pathology in scurfy mice is in part accompanied by autoantibodies such as antinuclear antibodies (ANA). ANA are serological hallmarks of several autoimmune disorders including autoimmune liver diseases (AILD). However, the underlying pathogenesis and the role of Treg in AILD remain to be elucidated. The present study therefore aimed to characterize the liver disease in scurfy mice. Methods: Sera from scurfy mice were screened for ANA by indirect immunofluorescence assay (IFA) and tested for a wide range of AILD-associated autoantibodies by enzyme-linked immunosorbent assay, line immunoassay, and addressable laser bead immunoassay. CD4+ T cells of scurfy mice were transferred into T cell-deficient B6/nude mice. Monoclonal autoantibodies from scurfy mice and recipient B6/nude mice were tested for ANA by IFA. Liver tissue of scurfy mice was analyzed by conventional histology. Collagen deposition in scurfy liver was quantified via hepatic hydroxyproline content. Real-time quantitative PCR was used to determine fibrosis-related hepatic gene expression. Hepatic immune cells were differentiated by flow cytometry. Results: All scurfy mice produced ANA. AILD-associated autoantibodies, predominantly antimitochondrial antibodies, were detected at significantly higher levels in scurfy sera. CD4+ T cells from scurfy mice were sufficient to induce anti-dsDNA autoantibodies and ANA with an AILD-related nuclear envelope staining pattern. Liver histology revealed portal inflammation with bile duct damage and proliferation, as in primary biliary cholangitis (PBC), and interface hepatitis with portal-parenchymal necroinflammation, as found in autoimmune hepatitis (AIH). In scurfy liver, TNFα and fibrosis-related transcripts including Col1a1, Timp1, Acta2, Mmp2, and Mmp9 were upregulated. The level of proinflammatory monocytic macrophages (Ly-6Chi) was increased, while M2-type macrophages (CD206+) were downregulated compared to wildtype controls. Despite severe hepatic inflammation, fibrosis did not develop within 25 days, which is close to the lifespan of scurfy mice. Discussion: Our findings suggest that Treg-deficient scurfy mice spontaneously develop clinical, serological, and immunopathological characteristics of AILD with overlapping features of PBC and AIH.

Increased hepatic fibrosis and JNK2-dependent liver injury in mice exhibiting hepatocyte-specific deletion of cFLIP.

Chronic liver disease promotes hepatocellular injury involving apoptosis and triggers compensatory regeneration that leads to the activation of quiescent stellate cells in the liver. The deposition of extracellular matrix from activated myofibroblasts promotes hepatic fibrosis and the progression to cirrhosis with deleterious effects on liver physiology. The role of apoptosis signaling pathways in the development of fibrosis remains undefined. The aim of the current study was to determine the involvement of the caspase-8 homologue cellular FLICE-inhibitory protein (cFLIP) during the initiation and progression of fibrosis. Liver injury and fibrosis from carbon tetrachloride (CCl(4)) and thioacetamide (TAA) were examined in mice exhibiting a hepatocyte-specific deletion of cFLIP (flip(-/-)). Acute liver injury from CCl(4) and TAA were enhanced in flip(-/-) mice. This was accompanied by increased activation of caspase-3 and -9, pronounced phosphorylation of JNK, and decreased phosphorylation of Erk. Deletion of the cJun NH(2)-terminal kinase 2 (JNK2) in flip(-/-) mice protected from injury. Hepatic fibrosis was increased at baseline in 12-wk-old flip(-/-) mice, and progression of fibrosis from TAA was accelerated compared with the wild type. In conclusion, deletion of cFLIP in hepatocytes leads to increased fibrosis and accelerated fibrosis progression. This is accompanied by increased injury involving the activation of caspases and JNK2. Thus predisposition to liver injury involving increased hepatocellular apoptosis is a critical mediator of accelerated fibrogenesis, and prevention of liver injury will be a most important measure for patients with chronic liver disease.

Effects of urbanization on vulnerability to heat-related mortality in urban and rural areas in South Korea: a nationwide district-level time-series study.

BACKGROUND: Although urbanization is often an important topic in climate change studies, the complex effect of urbanization on heat vulnerability in urban and rural areas has rarely been studied. We investigated the disparate effects of urbanization on heat vulnerability in urban and rural areas, using nationwide data. METHODS: We collected daily weather data for all 229 administrative districts in South Korea (2011-17). Population density was applied as an urbanization indicator. We calculated the heat-mortality risk using a distributed lag nonlinear model and analysed the relationship with population density. We also examined district characteristics that can be related to the spatial heterogeneity in heat-mortality risk. RESULTS: We found a U-shaped association between population density and heat-mortality risk, with the highest risk for rural populations; in urban areas, risk increases with increasing population density. Higher heat-mortality risk was associated with a lower number of hospital beds per person and higher percentage of people requiring recuperation. The association between hospital beds and heat-mortality risk was prominent in high-density urban areas, whereas the association between the percentage of people requiring recuperation and heat-mortality risk was pronounced in rural areas. CONCLUSIONS: Our findings indicate that the association between population density and heat-mortality risk is different in urban and rural areas, and that district characteristics related to heat-mortality risk also differ by urbanicity. These results can contribute to understanding the complex role of urbanization on heat vulnerability and can provide evidence to policy makers for prioritizing resources.

Dietary naringenin increases hepatic peroxisome proliferators-activated receptor α protein expression and decreases plasma triglyceride and adiposity in rats.

BACKGROUND: Naringenin, a flavonoid present in grapefruit, has recently been shown to exert hypolipidemic and hypocholesterolemic effects, which has a particular importance for protecting against chronic diseases. However, the lipid-lowering potential of naringenin at the concentrations in the dietary range and its underlying mechanisms have yet to be fully elucidated. AIM: The aim of the present study was (1) to investigate the effects of dietary naringenin on plasma and hepatic triglyceride and cholesterol levels and on adipose deposition in rat and (2) to determine the contribution of hepatic peroxisome proliferators-activated receptor α (PPARα) expression to fatty acid oxidation. METHODS: Male Long-Evans hooded rats were fed a diet supplemented with naringenin (0.003, 0.006, and 0.012%) for 6 weeks. We analyzed plasma and hepatic lipid contents and determined the protein expression of PPARα, carnitine-palmitoyl transferase 1L (CPT-1), and uncoupling protein 2 (UCP2), all of which are critical genes for fatty acid oxidation. RESULTS: Naringenin supplementation caused a significant reduction in the amount of total triglyceride and cholesterol in plasma and liver. In addition, naringenin supplementation lowered adiposity and triglyceride contents in parametrial adipose tissue. Naringenin-fed animals showed a significant increase in PPARα protein expression in the liver. Furthermore, expression of CPT-1 and UCP2, both of which are known to be regulated by PPARα, was markedly enhanced by naringenin treatment. CONCLUSIONS: Our results indicate that the activation of PPARα transcription factor and upregulation of its fatty acid oxidation target genes by dietary naringenin may contribute to the hypolipidemic and anti-adiposity effects in vivo.

Effects of associated bacteria on the pathogenicity and reproduction of the insect-parasitic nematode Rhabditis blumi (Nematoda: Rhabditida).

Three bacteria, Alcaligenes faecalis , Flavobacterium sp., and Providencia vermicola , were isolated from dauer juveniles of Rhabditis blumi . The pathogenic effects of the bacteria against 4th instar larvae of Galleria mellonella were investigated. Providencia vermicola and Flavobacterium sp. showed 100% mortality at 48 h after haemocoelic injection, whereas A. faecalis showed less than 30% mortality. Dauer juveniles showed 100% mortality against G. mellonella larvae, whereas axenic juveniles, which do not harbor associated bacteria, exhibited little mortality. All of the associated bacteria were used as a food source for nematode growth, and nematode yield differed with bacterial species. Among the bacterial species, P. vermicola was most valued for nematode yield, showing the highest yield of 5.2 × 10(4) nematodes/mL in the plate. In bacterial cocultures using two of the three associated bacteria, one kind stimulated the other. The highest total bacterial yield of 12.6 g/L was obtained when the inoculum ratio of P. vermicola to A. faecalis was 10:1. In air-lift bioreactors, the nematode growth rate increased with an increasing level of dissolved oxygen. The maximum nematode yield of 1.75 × 10(5) nematodes/mL was obtained at 192 h with an aeration rate of 6 vvm.