Katsushi Amano

Chemical Xenobiotics and Mitochondrial Autoantigens in Primary Biliary Cirrhosis: Identification of Antibodies against a Common Environmental, Cosmetic, and Food Additive, 2-Octynoic Acid

Emerging evidence has suggested environmental factors as causative agents in the pathogenesis of primary biliary cirrhosis (PBC). We have hypothesized that in PBC the lipoyl domain of the immunodominant E2 component of pyruvate dehydrogenase (PDC-E2) is replaced by a chemical xenobiotic mimic, which is sufficient to break self-tolerance. To address this hypothesis, based upon our quantitative structure-activity relationship data, a total of 107 potential xenobiotic mimics were coupled to the lysine residue of the immunodominant 15 amino acid peptide of the PDC-E2 inner lipoyl domain and spotted on microarray slides. Sera from patients with PBC (n = 47), primary sclerosing cholangitis (n = 15), and healthy volunteers (n = 20) were assayed for Ig reactivity. PBC sera were subsequently absorbed with native lipoylated PDC-E2 peptide or a xenobiotically modified PDC-E2 peptide, and the remaining reactivity analyzed. Of the 107 xenobiotics, 33 had a significantly higher IgG reactivity against PBC sera compared with control sera. In addition, 9 of those 33 compounds were more reactive than the native lipoylated peptide. Following absorption, 8 of the 9 compounds demonstrated cross-reactivity with lipoic acid. One compound, 2-octynoic acid, was unique in both its quantitative structure-activity relationship analysis and reactivity. PBC patient sera demonstrated high Ig reactivity against 2-octynoic acid-PDC-E2 peptide. Not only does 2-octynoic acid have the potential to modify PDC-E2 in vivo but importantly it was/is widely used in the environment including perfumes, lipstick, and many common food flavorings.

Xenobiotic-Induced Loss of Tolerance in Rabbits to the Mitochondrial Autoantigen of Primary Biliary Cirrhosis Is Reversible

Previous work has demonstrated that immunization of rabbits with the xenobiotic 6-bromohexanoate coupled to BSA breaks tolerance and induces autoantibodies to mitochondria in rabbits. Such immunized rabbits develop high-titer Abs to pyruvate dehydrogenase complex (PDC)-E2, the major autoantigen of primary biliary cirrhosis. In efforts to map the fine specificity of these autoantibodies, rabbits were immunized biweekly with 6-bromohexanoate-BSA and screened for reactivity using a unique xenobiotic-peptide-agarose microarray platform with an emphasis on identifying potential structures that mimic the molecular image formed by the association of lipoic acid with the immunodominant PDC-E2 peptide. Essentially, a total of 23 xenobiotics and lipoic acid were coupled to the 12-mer peptide backbones, PDC, a mutant PDC, and albumin. As expected, we succeeded in breaking tolerance using this small organic molecule coupled to BSA. However, unlike multiple experimental methods of breaking tolerance, we report in this study that, following continued immunization, the rabbits recover tolerance. With repeated immunization, the response to the rPDC-E2 protein increased with a gradual reduction in autoantibodies against the lipoic acid-peptide, i.e., the primary tolerance-breaking autoantigen. Detailed analysis of this system may provide strategies on how to restore tolerance in patients with autoimmune disease.

Analysis of the serum bile Acid composition for differential diagnosis in patients with liver disease.

Objectives. We determined the serum bile acid (BA) composition in patients with liver diseases and healthy volunteers to investigate the relationship between the etiologies of liver disease and BA metabolism. Material and Methods. Sera from 150 patients with liver diseases and 46 healthy volunteers were obtained. The serum concentrations of the 16 different BAs were determined according to the LC-MS/MS method and were compared between the different liver diseases. Results. A total of 150 subjects, including patients with hepatitis C virus (HCV) (n = 44), hepatitis B virus (HBV) (n = 23), alcoholic liver disease (ALD) (n = 21), biliary tract disease (n = 20), nonalcoholic fatty liver disease (NAFLD) (n = 13), and other liver diseases (n = 29), were recruited. The levels of UDCA and GUDCA were significantly higher in the ALD group, and the levels of DCA and UDCA were significantly lower in the biliary tract diseases group than in viral hepatitis group. In the UDCA therapy (−) subgroup, a significantly lower level of TLCA was observed in the ALD group, with lower levels of CDCA, DCA, and GLCA noted in biliary tract diseases group compared to viral hepatitis group. Conclusions. Analysis of the BA composition may be useful for differential diagnosis in liver disease.

Oxidative stress markers, secondary bile acids and sulfated bile acids classify the clinical liver injury type: Promising diagnostic biomarkers for cholestasis.

Clinicians sometimes encounter difficulty in choosing a therapeutic strategy due to the uncertainty regarding the type of liver injury. In particular, cholestasis is difficult to diagnose by conventional markers at an early stage of disease. The aim of this study was to identify promising biomarkers for distinguishing the symptom-based types of liver injury (e.g. hepatocellular injury, cholestasis), which was derived from a rigorously statistical perspective. The associations between diagnostic biomarkers (e.g. bile acid components, oxidative stress markers and liver fibrosis markers) and the liver injury types were assessed by a multiple logistic regression analysis using 304 blood samples from patients with liver disease. As a result, reductions in the lithocholic acid (LCA) and deoxycholic acid (DCA) levels, and elevation of the serum sulfated bile acid (SSBA), liver fibrosis marker IV collagen (type IV collagen), hyaluronic acid (HA) and reactive oxygen species (ROS) levels were all significantly associated with cholestasis. On the other hand, elevations in the LCA and type IV collagen levels, and a reduction in the ursodeoxy cholic acid (UDCA) level, were significantly associated with hepatocellular injury. The receiver operating characteristic (ROC) analyses showed that the largest area under the ROC curve (AUC) was found for ROS, followed by DCA, HA, LCA, SSBA and type IV collagen in the cholestatic-type cases. These results indicated that ROS, the secondary bile acid levels such as DCA and LCA, and SSBA are promising biomarkers for cholestasis and for classifying the type of liver injuries. This comprehensive approach will allow for an accurate diagnosis, which will facilitate the selection of an appropriate therapy at the onset of disease.

Successful Treatment of Budd-Chiari Syndrome with Balloon Dilatation Angioplasty

Munenori Itagaki1, Kenichi Satoh1, Katsushi Amano1, Satoshi Sutoh1, Hiroshi Abe1, Yoshio Aizawa1, Ashida Hirokazu2, Kenichi Narita2, Shinsuke Takenaga2, Keitarou Enoki2 1Department of Gastroenterology and Hepatology Internal Medicine, Jikei University 2Department of Radiology, Jikei University; Nishi-Shimbashi, Minato-ku, Tokyo, Japan. Successful Treatment of Budd-Chiari Syndrome with Balloon Dilatation Angioplasty JOURNAL OF CASE REPORTS 2016;6(1):17-20