Jun-ichi Masuda

Recent insights into digestive motility in functional dyspepsia

Functional gastrointestinal disorders, such as functional dyspepsia (FD) and irritable bowel syndrome, are common pathologies of the gut. FD is a clinical syndrome defined as chronic or recurrent pain or discomfort of unknown origin in the upper abdomen. The pathophysiological mechanisms responsible for FD have not been fully elucidated, but new ideas regarding its pathophysiology and the significance of the pathophysiology with respect to the symptom pattern of FD have emerged. In particular, there is growing interest in alterations in gastric motility, such as accommodation to a meal or gastric emptying, and visceral sensation in FD. The mechanisms underlying impaired gastroduodenal motor function are unclear, but possible factors include abnormal neurohormonal function, autonomic dysfunction, visceral hypersensitivity to acid or mechanical distention, Helicobacter pylori infection, acute gastrointestinal infection, psychosocial comorbidity, and stress. Although the optimum treatment for FD is not yet clearly established, acid-suppressive drugs, prokinetic agents, eradication of H. pylori, and antidepressants have been widely used in the management of patients with FD. The therapeutic efficacy of prokinetics such as itopride hydrochloride and mosapride citrate in the treatment of FD is supported by the results of relatively large and well-controlled studies. In addition, recent research has yielded new therapeutic agents and modalities for dysmotility in FD, including agonists/antagonists of various sensorimotor receptors, activation of the nitrergic pathway, kampo medicine, acupuncture, and gastric electric stimulation. This review discusses recent research on the pathophysiology of and treatment options for FD, with special attention given to digestive dysmotility.

Baseline Serum Cholesterol Is Associated with a Response to Pegylated Interferon Alfa-2b and Ribavirin Therapy for Chronic Hepatitis C Genotype 2

Background. HCV infection is associated with lipid disorders because this virus utilizes the host lipid metabolism to sustain its life cycle. Several studies have indicated that higher concentrations of serum cholesterol and LDL before treatment are important predictors of higher rates of sustained virological response (SVR). However, most of these studies involved patients infected with HCV genotype 1. Thus, we performed a multi-institutional clinical study to evaluate the impact of lipid profiles on SVR rates in patients with HCV genotype 2. Methods. A total of 100 chronic hepatitis C patients with HCV genotype 2 who received peg-IFN alfa-2b and ribavirin therapy were consecutively enrolled. The significance of age, sex, BMI, AST level, ALT level, WBC, hemoglobin, platelet count, gamma-glutamyltransferase, total cholesterol level (TC), LDL level, HCV RNA, and histological evaluation was examined for SVR using logistic regression analysis. Results. The 100 patients infected with HCV genotype 2 were divided into 2 groups, an SVR group and a non-SVR group. Characteristics of each group were subsequently compared. There was no significant difference in the level of HCV RNA, BMI, platelet, TG, or stage of fibrosis between the groups. However, there were significant differences in the levels of TC and LDL-C. In multivariate logistic regression analysis using baseline characteristics, high TC level was an independent and significant risk factor (relative risk 18.59, P = 0.015) for SVR. Conclusion. Baseline serum total cholesterol levels should be considered when assessing the likelihood of sustained treatment response following the course of peg-IFN and ribavirin therapy in patients with chronic HCV genotype 2 infection.

Primary biliary cirrhosis among atomic bomb survivors in Nagasaki, Japan

Despite rapid progress in methods for analyzing radiation effects, much remains to be learned about the mechanisms and processes of radiation-induced immunological dysfunction. Among 17,899 sera obtained from atomic bomb survivors in Nagasaki, Japan, sera from 484 participants who complied with a reexamination for alkaline phosphatase (ALP) were tested for antimitochondrial antibody (AMA) by indirect immunofluorescence, and autoantibodies against 2-oxo-acid dehydrogenase complex (2-OADC) by immunoblotting to investigate the prevalence of primary biliary cirrhosis (PBC). Of these 484 sera, 28 (5.8%) were seropositive for AMA. The 484 participants were divided into three groups according to distance from the hypocenter: 72 who were exposed within 1999 m (closest group), 368 from 2000 to 5999 m (intermediate distant group), and 44 outside 6000 m (distant group). The positivity rates for AMA in these three groups were 6/72 (8.3%), 22/368 (6.0%), and 0/44 (0%), respectively (P =.08). Furthermore, high titers ( > 1:320) of AMA were observed in 3/6 (50%) AMA-positive sera from the closest group, in contrast to 4/22 (18%) from the intermediate distant group, although there was no significant correlation between AMA titer and distance from the hypocenter (P =.07). Of these 28 AMA-positive sera, 11 (39%) were from participants who had already been diagnosed with PBC, and 25 (89%) contained antibodies against at least one component of 2-OADC enzymes by immunoblotting. Therefore, the prevalence of PBC was estimated to be at least 615 cases per million (792 per million women). Our results suggest that the prevalence of PBC in atomic bomb survivors in Nagasaki is higher than that reported for the general population in Japan, and a further survey of the environmental factors, including radiation exposure, that predispose to PBC would be needed for understanding this disease of unknown etiology.

Correlation between histopathological findings of the liver and IgA class antibodies to 2-oxo-acid dehydrogenase complex in primary biliary cirrhosis

Although anti-mitochondrial antibody (AMA) is the characteristic serological feature of primary biliary cirrhosis (PBC), its pathogenetic role remains unclear. We tested sera from 72 Japanese patients with histologically confirmed PBC for AMA by indirect immunofluorescence, anti-pyruvate dehydrogenase complex (PDC) by enzyme inhibition assay, immunoglobulin (Ig) G class anti-PDC by ELISA, and IgG, IgM, and IgA class anti-2-oxo-acid dehydrogenase complex (2-OADC) by immunoblotting. Of the 72 sera, 60 (83%), 50 (69%), 42 (58%), and 71 (99%) were positive for AMA by immunofluorescence, enzyme inhibition assay, ELISA, and immunoblotting, respectively. There was no significant correlation between histological stages and AMA by immunofluorescence, PDC inhibitory antibodies by enzyme inhibition assay, IgG class anti-PDC antibodies by ELISA, or IgG and IgM class anti-2-OADC by immunoblotting. IgA class anti-2-OADC by immunoblotting was more frequent in stages 2–4 than in stage 1 (P = 0.0083). Of the IgA class anti-2-OADC, anti-PDC-E2 (74 kDa) and anti-E3BP (52 kDa) were more frequent in stages 2–4 than in stage 1 (P = 0.0253 and 0.0042, respectively). Further examination of histopathological findings in 53 of 72 liver biopsy specimens showed that IgA class anti-PDC-E2 and IgA class anti-E3BP were associated with bile duct loss, and IgA class anti-PDC-E2 was also associated with interface hepatitis and atypical ductular proliferation. IgA is known to be secreted into the bile through biliary epithelial cells, implying that IgA class anti-PDC-E2 and E3BP may have a specific pathogenetic role during their transport into the bile by binding to their target antigen(s) in biliary epithelial cells, and this may be followed by dysfunction and finally destruction of biliary epithelial cells. Our present results suggest that these autoantibodies against 2-OADC detected by immunoblotting may be associated with the pathogenesis and pathologic progression of PBC.

Evaluation of newly developed ELISA using "MESACUP-2 test mitochondrial M2" kit for the diagnosis of primary biliary cirrhosis.

OBJECTIVES An enzyme-linked immunosorbent assay (ELISA) using MESACUP-2 Test Mitochondria M2 kit (new-M2 ELISA) has recently become commercially available. The aim of this study was to evaluate the clinical utility of this newly developed ELISA for the diagnosis of primary biliary cirrhosis (PBC). DESIGN AND METHODS We tested the immunoreactivity of sera from 82 Japanese PBC patients to the 2-oxo-acid dehydrogenase complex (2-OADC) enzymes by indirect immunofluorescence, enzyme inhibition assay using commercially available TRACE Enzymatic Mitochondrial Antibody (M2) Assay (EMA) kit, commercial ELISAs using MESACUP Mitochondria M2 kit (old-M2 ELISA) and new-M2 ELISA, and immunoblotting on bovine heart mitochondria. RESULTS Each test gave the following positive results; antimitochondrial antibodies (AMA) by immunofluorescence in 71 (87%) out of the 82 sera, enzymatic inhibitory antibody to pyruvate dehydrogenase complex (PDC) by EMA in 61 (74%), immunoglobulin (Ig) G class anti-PDC antibody by old-M2 ELISA in 55 (67%), IgG/M/A class anti-E2 subunit of PDC (PDC-E2)/anti-E2 subunit of branched chain oxo-acid dehydrogenase complex (BCOADC-E2)/anti-E2 subunit of 2-oxoglutarate dehydrogenase complex (OGDC-E2) antibodies by new-M2 ELISA in 73 (89%), and IgG, IgM, or IgA class antibodies against at least one of the 2-OADC enzymes by immunoblotting in 82 (100%). Fifty-three of the 82 sera (65%) were all positive by these five assays. Of the 18 sera that were positive by new-M2 ELISA but negative by old-M2 ELISA, 12 were theoretically interpretable. Of the 11 sera that were negative for AMA by immunofluorescence but positive for at least one of anti-2-OADC enzymes by immunoblotting, four (36%) were positive by new-M2 ELISA, whereas only two and one sera were positive by EMA and old-M2 ELISA, respectively. CONCLUSIONS Our results indicated that the sensitivity of the newly developed new-M2 ELISA was higher than that of EMA and old-M2 ELISA, and comparable with that of immunofluorescence. However, it is still unclear whether the new-M2 ELISA could replace the conventional immunofluorescence testing for routine assay requests because six (7%) sera showed discrepant results between these two assays.

A possible mouse model for spontaneous cholangitis: serological and histological characteristics of MRL/lpr mice.

Aims: MRL/Mp‐ lpr/lpr (MRL/ lpr ) mice spontaneously develop lymphadenopathy, hypergammaglobulinaemia, serum auto‐antibodies, and a generalised auto‐immune disease including glomerulonephritis and arthritis, and have been used as a model for the study of systemic lupus erythematosus. Recently, MRL/ lpr mice were also reported as a potentially suitable animal model of primary biliary cirrhosis (PBC). The aim of this study was to determine the suitability of MRL/Mp‐ lpr/lpr (MRL/ lpr ) mice as an experimental auto‐immune‐mediated cholangitis model for PBC. Methods: We investigated the serum hepatobiliary enzymes, histopathological findings, and the target antigen of antimitochondrial antibodies (AMA) in MRL/ lpr mice. Results: Serum levels of total bilirubin and hepatobiliary enzymes including alanine aminotransferase (ALT), leucine aminopeptidase (LAP), and gamma‐glutamyl transpeptidase (G‐GTP) in older‐aged (over 20 weeks old) MRL/ lpr or MRL/Mp‐ + / + (MRL/ + ) mice were not significantly higher than those in younger (8‐12 weeks old) MRL/ lpr, MRL/ +, or older‐aged control mice (C3H/HeJ and BALB/C mice). Histopathologically, 24 of 47 (51%) older‐aged MRL/ lpr mice showed evidence of cholangitis, compared with two of 20 (10%) younger MRL/ lpr mice. Especially, epithelioid granuloma and/or bile duct loss were seen in 11 out of 47 (23%) older‐aged MRL/ lpr mice, whereas such findings were seen in only one of 20 (5%) younger MRL/ lpr mice. None of the MRL/ +, C3H/HeJ, and BALB/C mice developed cholangitis. The target antigens of AMA were not pyruvate dehydrogenase complex but 2‐oxoglutarate dehydrogenase complex and/or branched‐chain oxo‐acid dehydrogenase complex as confirmed by immunoblotting. There was no significant correlation between the presence of AMA and severity of histological lesions in older‐aged MRL/ lpr mice, and there were no significant differences in these biochemical data, the proportion of mice with portal inflammation, cholangitis and AMA between male and female MRL/ lpr mice. Conclusion: Although several clinical features were incompatible with PBC, the serological and histopathological features of MRL/ lpr mice indicate that these mice can be used as an experimental immune‐mediated cholangitis model for PBC.

The sperm mitochondria-specific translocator has a key role in maternal mitochondrial inheritance

The mechanism of maternal mitochondrial inheritance in animals involves the selective elimination of sperm mitochondria by the elimination factor of the egg and the sperm mitochondria‐specific factor. In vitro fertilization using sperm from isogenic mice incorporating heterospecific mitochondrial DNA (mtDNA) showed that the number of PCR positives of sperm mtDNA in two‐cell embryos was significantly increased following sperm incubation with anti‐tetratricopeptide repeat‐containing protein involved in spermatogenesis (tpis) protein, anti‐translocator of mitochondrial outer membrane (Tom) 22 and anti‐Tom40 antibodies. The treatment of fertilized eggs with EGTA and other endonuclease inhibitors increased the sperm mtDNA levels. We conclude that the elimination factor, which is probably an endonuclease, is selectively received by the tpis protein of the sperm mitochondrial outer membrane within the egg. It is then transported into the sperm mitochondria by Tom22 and Tom40, where it destroys the sperm mtDNA, establishing the maternal inheritance of mtDNA.

Changes in titers of antimitochondrial and antinuclear antibodies during the course of primary biliary cirrhosis

Abstract A case of primary biliary cirrhosis (PBC) in whom a complete biochemical (serum bilirubin, transaminases and alkaline phosphatase) remission was noted after combination treatment with ursodeoxycholic acid (UDCA) and corticosteroid is reported. The antimitochondrial antibody (AMA) detected by indirect immunofluorescence was initially positive, and the antinuclear antibody (ANA) was negative, but these two antibodies subsequently fluctuated independently (AMA‐positive/ANA‐negative, AMA‐negative/ANA‐negative, AMA‐negative/ANA‐positive, AMA‐positive/ANA‐positive, and again AMA‐negative/ANA‐positive) in spite of a lack of histopathological improvement in the liver after treatment. The clinical presentation in our case suggests that in some cases the diagnosis of PBC or so‐called autoimmune cholangitis (AIC) might depend on the ‘phase’ of the same disease. Our results also suggest that detailed immunoreactive profiles against 2‐oxo‐acid dehydrogenase complex (2‐OADC) enzymes by using immunoblotting, together with a serial histological examination, should provide more precise information for a diagnosis of PBC.

Automated enzymatic mitochondrial antibody assay for the diagnosis of primary biliary cirrhosis: applications of a routine diagnostic tool for the detection of antimitochondrial antibodies.

Background and Aims: An automated enzymatic mitochondrial antibody assay (EMA) kit for the diagnosis of primary biliary cirrhosis (PBC) has become commercially available recently. The aim of this study was to assess the clinical utility of the enzyme inhibition assay using this EMA kit for the diagnosis of PBC.

Frequency of elevated biomarkers in patients with cryptogenic hepatocellular carcinoma

Background The incidence of hepatocellular carcinoma (HCC) continues to increase in Japan, but the clinical characteristics of Japanese patients with HCC have not been well described. The aim of this study was to determine the frequencies and utilities of elevated α-fetoprotein (AFP) and des-gamma-carboxy prothrombin (DCP) levels as biomarkers in cryptogenic HCC. Material/Methods A total of 2638 patients with HCC diagnosed between 1999 and 2010 in the Nagasaki Association Study of Liver (NASLD) were recruited for this study. The cause of HCC was categorized into 4 groups; HCC-B, HCC-C, HCC-BC, and HCC-nonBC. The significance of factors was examined for HCC-nonBC using logistic regression analysis in all patients. Results Multivariate analysis identified age, sex, BMI, alcohol consumption, platelet count, AST, ALT, AFP, DCP, and TNM stage as independent and significant risk factors for HCC-nonBC. According to TNM stage, the median AFP levels in HCC-nonBC with TNM stages I, II, and III were significantly lower than in either HCC-B or HCC-C. In TNM stage IV, the median AFP level in HCC-nonBC was significantly lower than in either HCC-B or HCC-BC. The median DCP levels in HCC-nonBC with TNM stages I and II were significantly higher than those in either HCC-B or HCC-C. In TNM stage III, the median DCP level in HCC-nonBC was significantly higher than that in HCC-C. Conclusions DCP was more sensitive than AFP for the diagnosis of early stage cryptogenic HCC. DCP should be used as the main serum test for cryptogenic HCC detection.