Tomohiro Katsumi

Animal Models of Primary Biliary Cirrhosis

Primary biliary cirrhosis (PBC) is characterized histologically by the presence of chronic non-suppurative destructive cholangitis of the small interlobular bile duct, leading to chronic progressive cholestasis. Most PBC patients are asymptomatic and have a reasonable prognosis, but a few develop esophageal varices or jaundice, rapidly leading to liver failure within a short period. As multiple factors appear to be involved in the onset of PBC, its clinical course may be complicated. Therefore, the use of an animal model would be valuable for clarifying the pathogenesis of PBC. Here, we review recent data of selected PBC models, particularly spontaneous models, xenobiotic immunized models, and infection-triggered models. There are a number of spontaneous models: the NOD.c3c4, dominant-negative TGF-β receptor II, IL-2Rα−/−, Scurfy, and Ae2a,b−/− mice. These animal models manifest distinct clinical and immunological features similar, but also often different, from those of human PBC. It is clear that a combination of genetic predisposition, environmental factors, and immunological dysfunction contribute to the pathogenesis of PBC. The diverse clinical course and complexity of the immunological mechanisms of PBC cannot be fully recapitulated solely any single animal model. The challenge remains to develop a progressive PBC disease model that exhibits fibrosis, and ultimately hepatic failure.

Dynamics of serum metabolites in patients with chronic hepatitis C receiving pegylated interferon plus ribavirin: A metabolomics analysis

OBJECTIVES Serum samples from patients with chronic hepatitis C were subjected to metabolomics analysis to clarify the pretreatment characteristics of their metabolites and also changes in specific metabolites resulting from antiviral therapy with pegylated interferon plus ribavirin (PegIFN/RBV). MATERIALS/METHODS The serum levels of low-molecular-weight metabolites in the twenty patients before and 24weeks after completion of PegIFN/RBV therapy were analyzed using capillary electrophoresis and liquid chromatography-mass spectrometry. RESULTS Ten patients showed a non-virological response (NVR) and 10 achieved a sustained virological response (SVR) with eradication of viremia. The pretreatment levels of tryptophan were significantly higher in the patients of SVR than in those of NVR (p=0.010). The area under the curve (AUC) value of tryptophan calculated from the receiver operating characteristic (ROC) curve for discriminating SVR from NVR was 0.84 (95% confidential interval, 0.66-1.02, p=0.010). The ROC curve of multiple logistic regression model incorporating the pretreatment levels of tryptophan and γ-glutamate-arginine showed that the AUC value was highly significant (AUC=0.92, 95% confidential interval, 0.79-1.05, p=0.002). Twenty four weeks after completion of treatment, the levels of γ-glutamyl dipeptides, glutamic acid, 5-oxoproline, glucosamine and methionine sulfoxide were decreased, whereas those of 5-methoxy-3-indoleacetate, glutamine, kynurenine and lysine were increased significantly (p<0.05) in both the NVR and SVR patients. CONCLUSIONS The pretreatment serum levels of certain metabolites including tryptophan are associated with the response to PegIFN/RBV therapy. PegIFN/RBV therapy can ameliorate the oxidative stress responsible for glutathione metabolism.

Clinical manifestations of liver injury in patients with anorexia nervosa

The number of Japanese patients with anorexia nervosa (AN) is increasing as society changes. Mild liver injury is a complication of AN in around 30% of cases. In some rare instances, patients present with severe liver injury similar to acute liver failure. However, there are numerous uncertainties over the clinical characteristics of this condition. The objective of the present study was to clarify the clinical characteristics of AN complicated by liver injury and to investigate the factors related to hepatic complications.

Impaired mitochondrial β-oxidation in patients with chronic hepatitis C: relation with viral load and insulin resistance

BackgroundHepatic steatosis is often seen in patients with chronic hepatitis C (CH-C). It is still unclear whether these patients have an impaired mitochondrial β-oxidation. In this study we assessed mitochondrial β-oxidation in CH-C patients by investigating ketogenesis during fasting.MethodsThis study consisted of thirty patients with CH-C. Serum levels of insulin and hepatitis C virus (HCV) core protein were measured by chemiluminescence enzyme immunoassay. The subjects were then fasted, and venous blood samples were drawn 12 h and 15 h after the start of fasting. The levels of blood ketone bodies were measured by an enzymatic cycling method. The rate of change in total ketone body concentration was compared with that in eight healthy volunteers.ResultsThe rate of change in total ketone body concentration between 12 h and 15 h after the start of fasting was significantly lower in CH-C patients than in healthy volunteers (129.9% (8.5-577.3%) vs. 321.6% (139.6-405.4%); P <0.01). The rate of change in total ketone body concentration in patients with a serum level of HCV core protein of 10000 fmol/L or higher was significantly lower than in patients with a level of less than 10000 fmol/L (54.8% (8.5-304.3%) vs. 153.6% (17.1-577.3%); P <0.05). The rate of change in total ketone body concentration in patients with a homeostasis model assessment of insulin resistance (HOMA-IR) of 2.5 or higher was significantly lower than in patients with a HOMA-IR of less than 2.5 (56.7% (8.5-186.7%) vs. 156.4% (33.3-577.3%); P <0.01).ConclusionsThese results suggest that mitochondrial β-oxidation is impaired, possibly due to HCV infection in patients with CH-C.

MiR-139-5p is associated with inflammatory regulation through c-FOS suppression, and contributes to the progression of primary biliary cholangitis

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease characterized pathologically by destruction of intrahepatic bile ducts. PBC is largely classified into three subtypes based on clinical course: (i) gradually progressive, (ii) portal hypertension, and (iii) hepatic failure. Previous studies have indicated that serum levels of the pro-inflammatory cytokine TNF-α, is elevated in PBC patients with fibrosis. Although the severity of cholangitis might also be related to the PBC subtype, its etiology has been unclear. Several studies have shown that microRNAs (miRNAs) demonstrate specific expression patterns in various diseases. In the present study, we evaluated miRNA expression patterns among the PBC subtypes using comprehensive deep sequencing. We also carried out histologic examination by laser capture microdissection and investigated how the identified miRNAs were involved in PBC clinical progression using the miRNA transfection method. On average, ~11 million 32-mer short RNA reads per sample were obtained, and we found that the expression levels of 97 miRNAs differed significantly among the four groups. Heat mapping demonstrated that the miRNA profiles from hepatic failure and portal hypertension type were clustered differently from those of the gradually progressive type and controls. Furthermore, we focused on miR-139-5p, which has an adequate number of total short reads. Quantitative reverse transcription PCR showed that miR-139-5p was significantly downregulated in clinically advanced PBC. Also, examination of liver tissues demonstrated that the expression of lymphocyte-derived miR-139-5p was significantly higher in hepatocytes. In vitro, the level of TNF-α was significantly elevated in supernatant of cells with upregulation of miR-139-5p. Furthermore, c-FOS gene transcription was repressed. Thus, we have demonstrated a novel inflammation-regulatory mechanism involving TNF-α and c-FOS transcription through miR-139-5p in the NF-κB signaling pathway. We conclude that the specific miRNA miR-139-5p might be involved in the pathogenesis of PBC, especially during clinical progression.

Epiregulin promotes the emergence and proliferation of adult liver progenitor cells

We have previously reported that epiregulin is a growth factor that seems to act on liver progenitor cells (LPCs) during liver regeneration. However, the relationship between epiregulin and LPCs has remained unclear. The aim of the present study was to clarify the role of epiregulin during liver regeneration. The serum levels of epiregulin in patients with acute liver failure were examined. A liver injury model was developed using mice fed a diet containing 0.1% 3.5-diethoxycarbonyl-1.4-dihydrocollidine (DDC) to induce LPCs. We then evaluated the expression of epiregulin and LPCs in these mice. The proliferation of epithelial cell adhesion molecule + LPCs cultured with epiregulin was examined in vitro, and finally epiregulin was overexpressed in mouse liver. In patients with acute liver failure, serum epiregulin levels were elevated significantly. In DDC mice, LPCs emerged around the portal area. Epiregulin was also detected around the portal area during the course of DDC-induced liver injury and was partially coexpressed with Thy1. Serum epiregulin levels in DDC mice were also significantly elevated. Recombinant epiregulin augmented the proliferative capacity of the LPCs in a dose-dependent manner. In mice showing overexpression of epiregulin, the expression of PCNA on hepatocytes was increased significantly. Finally, LPCs emerged around the portal area after epiregulin gene delivery. We concluded that epiregulin promotes the proliferation of LPCs and DNA synthesis by hepatocytes and is upregulated in the serum of patients with liver injury. Furthermore, induction of epiregulin leads to the appearance of LPCs. Epiregulin would be a useful biomarker of liver regeneration.

Serum metabolome profiles characterized by patients with hepatocellular carcinoma associated with hepatitis B and C

AIM To clarify the characteristics of metabolite profiles in virus-related hepatocellular carcinoma (HCC) patients using serum metabolome analysis. METHODS The serum levels of low-molecular-weight metabolites in 68 patients with HCC were quantified using capillary electrophoresis chromatography and mass spectrometry. Thirty and 38 of the patients suffered from hepatitis B virus-related HCC (HCC-B) and hepatitis C virus-related HCC (HCC-C), respectively. RESULTS The main metabolites characteristic of HCC were those associated with glutathione metabolism, notably 13 γ-glutamyl peptides, which are by-products of glutathione induction. Two major profiles, i.e., concentration patterns, of metabolites were identified in HCC patients, and these were classified into two groups: an HCC-B group and an HCC-C group including some of the HCC-B cases. The receiver operating characteristic curve for the multiple logistic regression model discriminating HCC-B from HCC-C incorporating the concentrations of glutamic acid, methionine and γ-glutamyl-glycine-glycine showed a highly significant area under the curve value of 0.94 (95%CI: 0.89-1.0, P < 0.0001). CONCLUSION The serum levels of γ-glutamyl peptides, as well as their concentration patterns, contribute to the development of potential biomarkers for virus-related HCC. The difference in metabolite profiles between HCC-B and HCC-C may reflect the respective metabolic reactions that underlie the different pathogeneses of these two types of HCC.

Clinical Manifestations of Liver Dysfunction in Patients With Anorexia Nervosa

BACKGROUND AND AIMS: The number of Japanese patients with anorexia nervosa (AN) is increasing as society changes. Mild liver dysfunction is a complication of AN in around 30% of cases. In some rare instances, patients present with severe liver dysfunction similar to acute liver failure. However, there are numerous uncertainties over the clinical characteristics of this condition. The objective of the present study was to clarify the clinical characteristics of AN complicated by liver dysfunction and to investigate the factors related to hepatic complications. METHODS: Thirty-seven patients hospitalized at our institution with a diagnosis of AN were enrolled, and clinical data were obtained at the time of hospitalization. Subjects were categorized into three groups: 1) normal liver function, 2) moderate liver dysfunction, and 3) severe liver dysfunction. Subsequently, subgroup analysis was performed. RESULTS: All study subjects were female with an average age of 26 years and presenting with marked weight loss (mean body mass index, 13 kg/m). Thirteen subjects were found to have liver dysfunction. Patients with severe liver dysfunction (alanine aminotransferase >800IU/L) had a significantly higher level of blood urea nitrogen (BUN) and a higher BUN/creatinine ratio, and a lower body temperature and blood sugar level, compared with patients with normal liver function. CONCLUSIONS: Our present findings indicate that AN patients with severe liver dysfunction have a high degree of dehydration. This suggests that dysfunction of the hepatic circulation accompanying severe dehydration due to malnutrition, may be an important factor in the development of severe liver dysfunction in AN patients.