Chronic Bile Duct Injury Research Articles

Subsequent development of cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane in the printing company in Osaka, Japan.

After the report of 17 patients with occupational cholangiocarcinoma caused by long-term exposure to high concentrations of 1,2-dichloropropane and/or dichloromethane in a printing company in Osaka in 2014, additional five patients were diagnosed to have such cholangiocarcinoma. Cholangiocarcinoma was detected during regular health examination or follow-up for liver dysfunction in four of the five patients. Nearly all five patients presented with clinicopathological findings such as an elevated γ-glutamyl transpeptidase activity at the diagnosis, regional dilatation of intrahepatic bile ducts without tumor-induced obstruction, chronic bile duct injury, and precancerous/early cancerous lesions (biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct) at various sites of the bile duct. These findings were similar to those of the previous 17 patients. In total, cholangiocarcinoma developed in 22 of 95 workers exposed to 1,2-dichloropropane in the printing company. Of 22 patients with cholangiocarcinoma, 18 patients were members of 19 high exposure workers (≥1,500 ppm-years). These findings strengthen further the theory that 1,2-dichloropropane causes occupational cholangiocarcinoma. Regular health examination of workers exposed to 1,2-dichloropropane and/or dichloromethane is necessary to detect such cholangiocarcinoma because the potential of the carcinogenesis risk persists over the long term.

Occupational cholangiocarcinoma diagnosed 18\u2009years after the end of exposure to 1,2-dichloropropane and dichloromethane at a printing company: a case report

BackgroundCholangiocarcinoma due to exposure to 1.2-dichloropropane (DCP) or dichloromethane (DCM) is classified as occupational cholangiocarcinoma. We report a case of occupational cholangiocarcinoma diagnosed 18 years after the end of exposure to organic solvents at a printing company.Case presentationA 41-year-old man presented to our hospital with jaundice and anorexia. He had previously worked for 6 years at a printing company where an outbreak of occupational cholangiocarcinoma occurred and was exposed to high concentrations of organic solvents during his employment. Computed tomography demonstrated lower bile duct obstruction by the bulky nodal metastasis at the hepatoduodenal ligament with upstream biliary dilatation, an intraductal papillary tumor in the dilated left superior lateral bile duct (B2), and enlargement of the periaortic nodes. Clinical diagnosis of an unresectable invasive intraductal papillary neoplasm of the bile duct (IPNB) with extensive nodal metastasis was made. Although chemotherapy and laparoscopic gastrojejunostomy were performed for the duodenal obstruction, the patient died due to rupture of the tumor. Pathological examination of the autopsy specimen revealed well-differentiated adenocarcinoma at the stromal site along Glisson’s sheath in segment 3, an IPNB lesion without invasion in B2, and biliary intraepithelial neoplasia and chronic bile duct injury at various sites in the large bile ducts. The bulky lymph node (poorly differentiated adenocarcinoma with partial squamous cell differentiation) invaded the bile duct and duodenum.ConclusionsWe report a case of occupational cholangiocarcinoma that developed 18 years after the end of exposure to DCP and DCM. Long-term follow-up is required to carefully survey development of cholangiocarcinoma in workers with an occupational history of exposure to organic solvents.

Loss of Prolyl-Hydroxylase 1 Protects against Biliary Fibrosis via Attenuated Activation of Hepatic Stellate Cells

Liver fibrosis, eventually progressing to cirrhosis necessitating liver transplantation, poses a significant clinical problem. Oxygen shortage (hypoxia) and hypoxia-inducible transcription factors (HIFs) have been acknowledged as important drivers of liver fibrosis. The significance of oxygen-sensing HIF prolyl-hydroxylase (PHD) enzymes in this context has, however, remained elusive. In this study, we demonstrate that loss of PHD1 (PHD1-/-) attenuates the development of liver fibrosis in mice subjected to chronic bile duct injury, induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine. This effect was accompanied with reduced recruitment of inflammatory leukocytes and attenuated occurrence of profibrotic myofibroblasts in PHD1-/- livers. Further analyses focused on the significance of PHD1 in the activation of hepatic stellate cells (HSCs), which represent the driving force in liver fibrosis. Primary HSCs isolated from PHD1-/- mice displayed significantly attenuated myofibroblast differentiation and profibrogenic properties compared with HSCs isolated from wild-type mice. Consistently, the expression of various profibrogenic and promitogenic factors was reduced in PHD1-/- HSCs, without alterations in HIF-1α protein levels. Of importance, PHD1 protein was expressed in HSCs within human livers, and PHD1 transcript expression was significantly increased with disease severity in hepatic tissue from patients with liver fibrosis. Collectively, these findings indicate that PHD1 deficiency protects against liver fibrosis and that these effects are partly due to attenuated activation of HSCs. PHD1 may represent a therapeutic target to alleviate liver fibrosis.

Occupational cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane.

A cluster of cholangiocarcinoma among printing company workers who were exposed to 1,2‐dichloropropane and/or dichloromethane was classified by the Ministry of Health, Labour and Welfare of Japan on 1 October 2013 as “occupational cholangiocarcinoma”. At the time of the diagnosis of cholangiocarcinoma, levels of γ‐glutamyl transferase, and aspartate and alanine aminotransferases were elevated, and had been elevated in some patients several years prior to the diagnosis. Regional dilatation of intrahepatic bile ducts without tumor‐induced obstruction was characteristic in diagnostic imaging. Pathological examination found chronic bile duct injury with DNA damage, precancerous/preinvasive lesions such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct in various sites of the large bile ducts, and invasive cholangiocarcinoma such as mass‐forming type and intraductal growth‐type intrahepatic cholangiocarcinoma and mainly papillary‐type extrahepatic cholangiocarcinoma. Whole‐exome analysis of the cancerous tissues showed hypermutation, substantial strand bias, and unique trinucleotide mutational changes. Patients seemed to suffer high incidence of postoperative complications including intra‐abdominal, which might be related to chronic bile duct injury. Postoperative recurrence from multicentric origins occurred in some patients, as DNA‐injured bile ducts have high carcinogenic potential. Aggressive treatment, including second resections for such multicentric recurrences, appeared to be effective. In 2014, the International Agency for Research on Cancer classified 1,2‐dichloropropane as Group 1 (carcinogenic to humans) and dichloromethane as Group 2A (probably carcinogenic to humans) carcinogens.

Lymphocytes contribute to biliary injury and fibrosis in experimental xenobiotic-induced cholestasis

The etiology of chronic bile duct injury and fibrosis in patients with autoimmune cholestatic liver diseases is complex, and likely involves immune cells such as lymphocytes. However, most models of biliary fibrosis are not autoimmune in nature. Biliary fibrosis can be induced experimentally by prolonged exposure of mice to the bile duct toxicant alpha-naphthylisothiocyanate (ANIT). We determined whether lymphocytes contributed to ANIT-mediated biliary hyperplasia and fibrosis in mice. Hepatic accumulation of T-lymphocytes and increased serum levels of anti-nuclear-autoantibodies were evident in wild-type mice exposed to ANIT (0.05% ANIT in chow). This occurred alongside bile duct hyperplasia and biliary fibrosis. To assess the role of lymphocytes in ANIT-induced biliary fibrosis, we utilized RAG1-/- mice, which lack T- and B-lymphocytes. ANIT-induced bile duct injury, indicated by increased serum alkaline phosphatase activity, was reduced in ANIT-exposed RAG1-/- mice compared to ANIT-exposed wild-type mice. Despite this reduction in biliary injury, ANIT-induced bile duct hyperplasia was similar in wild-type and RAG1-/- mice. However, hepatic induction of profibrogenic genes including COL1A1, ITGβ6 and TGFβ2 was markedly attenuated in ANIT-exposed RAG1-/- mice compared to ANIT-exposed wild-type mice. Peribiliary collagen deposition was also reduced in ANIT-exposed RAG1-/- mice. The results indicate that lymphocytes exacerbate bile duct injury and fibrosis in ANIT-exposed mice without impacting bile duct hyperplasia.

Outcomes after resection of occupational cholangiocarcinoma.

Cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane is recognized as occupational cholangiocarcinoma. The aim of this study was to investigate the outcomes after resection of occupational cholangiocarcinoma to establish a treatment strategy for this disease. Clinicopathological findings and outcomes after surgical intervention in 20 patients with occupational cholangiocarcinoma were investigated. Of 20 the patients, curative resection was performed in 16 patients. Three patients underwent radiation at the stump of the bile ducts. Adjuvant chemotherapy was performed in 12 patients. Biliary intraepithelial neoplasia, intraductal papillary neoplasm of the bile duct, and/or chronic bile duct injury was detected in most subjects. Intraabdominal infection developed after surgery in nine patients. Cholangiocarcinoma recurred in 12 of the 20 patients. The recurrent tumors in five patients developed at a different part of the bile duct from the primary tumor and a second resection was performed in four of these five patients. The incidence of postoperative complications including intraabdominal infection was high in patients with occupational cholangiocarcinoma. Multicentric recurrence occurred not infrequently after surgery because the bile ducts had a high potential for the development of carcinoma. The aggressive treatment including second resection for the multicentric recurrence appeared to be effective.

Pathological spectrum of bile duct lesions from chronic bile duct injury to invasive cholangiocarcinoma corresponding to bile duct imaging findings of occupational cholangiocarcinoma.

We aimed to identify the pathological characteristics of occupational cholangiocarcinoma. We examined the location and distribution of the carcinomas: atypical epithelium including biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB); and chronic bile duct injuries in operative or autopsy liver specimens from 16 patients. We examined the detailed pathological findings and diagnostic imaging of three patients. Immunohistochemical analysis using primary antibodies against γH2AX and S100P was performed. BilIN and chronic bile duct injury were observed in 16 patients, and IPNB or invasive IPNB was observed in 11 patients. BilIN, IPNB, and/or chronic bile duct injury were observed in almost all the large bile ducts. Regional dilatation of the bile ducts without tumor-induced obstruction revealed such pathological changes. Highly positive results for the γH2AX and S100P markers were noted in invasive carcinoma, BilIN, and IPNB, whereas positive results for γH2AX and negative results for S100P were noted in non-neoplastic biliary epithelium. The carcinogenic process of occupational cholangiocarcinoma comprised chronic bile duct injury and DNA damage in almost all the large bile ducts, along with induction of precancerous lesions and development of invasive carcinoma. Such pathological findings reflected radiological changes on diagnostic imaging.

Intrahepatic cholangiocarcinoma in a worker at an offset color proof‐printing company: An autopsy case report

A 40-year-old Japanese man visited our hospital after test results indicated elevated hepatobiliary enzymes. He had worked at a printing plant for 8 years and been exposed to organic solvents, including 1,2-dichloropropane (1,2-DCP) and dichloromethane (DCM). Abdominal computed tomography (CT) showed an intrahepatic tumor with dilation of the intrahepatic bile duct. He was diagnosed with intrahepatic cholangiocarcinoma. He had no known risk factors for cholangiocarcinoma. Extended left hepatectomy with lymph node dissection was performed and the tumor was histologically diagnosed as well-differentiated adenocarcinoma. A histological examination also showed biliary intraepithelial preneoplastic lesions in non-cancerous liver areas. Two years after surgery, the patient developed jaundice, esophageal varices and ascites. A CT examination showed liver cirrhosis without recurrence of the cholangiocarcinoma. Although a liver transplantation was planned as a therapeutic option for his liver cirrhosis, his liver failure progressed rapidly and he died before transplantation could be performed. At autopsy, fibrosis was found in the whole liver, especially in the wall of the bile duct and periductal area suggesting chronic bile duct injury due to exposure to organic solvents. Taken together, the current case may suggest that exposure to organic solvents, including 1,2-DCP and DCM, is a risk factor for cholangiocarcinoma. Identifying risk factors for cholangiocarcinoma will help identify the mechanism and help prevent development of the disease.

The Antifibrinolytic Drug Tranexamic Acid Reduces Liver Injury and Fibrosis in a Mouse Model of Chronic Bile Duct Injury

Hepatic fibrin deposition has been shown to inhibit hepatocellular injury in mice exposed to the bile duct toxicant α-naphthylisothiocyanate (ANIT). Degradation of fibrin clots by fibrinolysis controls the duration and extent of tissue fibrin deposition. Thus, we sought to determine the effect of treatment with the antifibrinolytic drug tranexamic acid (TA) and plasminogen activator inhibitor-1 (PAI-1) deficiency on ANIT-induced liver injury and fibrosis in mice. Plasmin-dependent lysis of fibrin clots was impaired in plasma from mice treated with TA (1200 mg/kg i.p., administered twice daily). Prophylactic TA administration reduced hepatic inflammation and hepatocellular necrosis in mice fed a diet containing 0.025% ANIT for 2 weeks. Hepatic type 1 collagen mRNA expression and deposition increased markedly in livers of mice fed ANIT diet for 4 weeks. To determine whether TA treatment could inhibit this progression of liver fibrosis, mice were fed ANIT diet for 4 weeks and treated with TA for the last 2 weeks. Interestingly, TA treatment largely prevented increased deposition of type 1 collagen in livers of mice fed ANIT diet for 4 weeks. In contrast, biliary hyperplasia/inflammation and liver fibrosis were significantly increased in PAI-1(-/-) mice fed ANIT diet for 4 weeks. Overall, the results indicate that fibrinolytic activity contributes to ANIT diet-induced liver injury and fibrosis in mice. In addition, these proof-of-principle studies suggest the possibility that therapeutic intervention with an antifibrinolytic drug could form a novel strategy to prevent or reduce liver injury and fibrosis in patients with liver disease.

Role of Integrin αvβ6 in the Pathogenesis of Ischemia-Related Biliary Fibrosis After Liver Transplantation

Biliary fibrosis has been referred to as the "final common pathway" of acute and chronic bile duct injury after orthotopic liver transplantation (OLT). We studied the role of integrin αvβ6 in the pathogenesis of ischemia-related biliary fibrosis after OLT. The mouse nonarterialized OLT model with prolonged cold ischemia time was used in this study. A total of 54 FVB/N mice were divided into three groups: sham-operated group (sham, n=18), OLT group that was given the blocking antibody to integrin αvβ6 (OLT+antibody, n=18), and OLT group that was given the isotype control immunoglobulin G (OLT+vehicle, n=18). The expression of αvβ6 and major fibrosis-related genes were studied by real-time polymerase chain reaction and immunohistochemistry. Serum and bile were collected and analyzed biochemically. The histopathologic evaluation was performed to determine the severity of biliary fibrosis and bile duct injury. Integrin αvβ6 was highly expressed on newly formed bile ducts because of cholangiocyte proliferation and was gradually upregulated with the progression of biliary fibrosis after liver transplantation. αvβ6 transcripts closely correlated with fibrosis stages but not bile duct injury severity. Inhibition of αvβ6 attenuated peribiliary collagen deposition remarkably, induced significant downregulation of fibrogenic genes, and improved hepatic function. Integrin αvβ6 is strongly induced de novo in newly formed bile ducts because of cholangiocyte proliferation during ischemia-related biliary fibrogenesis after liver transplantation. Inhibition of αvβ6 could retard the progression of biliary fibrosis of liver allograft significantly, suggesting that αvβ6 is a potential target for the treatment of ischemic biliary complications.

Chronic Bile Duct Injury Associated with Fibrotic Matrix Microenvironment Provokes Cholangiocarcinoma in p53-Deficient Mice

Intrahepatic cholangiocarcinoma (CCA) is a lethal malignancy of the biliary epithelium associated with p53 mutations, bile duct injury, inflammation, and fibrosis. Here, to validate these processes in CCA, we developed a liver cirrhosis model driven by chronic intermittent toxin exposure, which provokes bile duct injury/necrosis and proliferation, fibroblast recruitment, and progressive extracellular matrix (ECM) changes. Fibrotic changes in the matrix microenvironment, typified by increased type I and III collagens and fibroblast recruitment, were shown to stimulate biliary epithelium hyperplasia with subsequent progression to malignant intrahepatic CCA only in mice harboring a p53 mutant allele. These murine CCAs bear histologic and genetic features of human intrahepatic CCA, including dense peritumoral fibrosis, increased inducible nitric oxide synthase, nitrotyrosine, and cyclooxygenase-2 expression, c-Met activation, cErbB2 overexpression, down-regulation of membrane-associated E-cadherin, and p53 codon 248 mutation. Thus, p53 deficiency, chronic bile duct injury/proliferation, and the fibrotic matrix microenvironment cooperate to induce intrahepatic CCA, highlighting the key role of the ECM microenvironment in this common liver cancer.

Liver transplantation for alcoholic cirrhosis: long term follow-up and impact of disease recurrence.

Alcoholic liver disease has emerged as a leading indication for hepatic transplantation, although it is a controversial use of resources. We aimed to examine all aspects of liver transplantation associated with alcohol abuse. Retrospective cohort analysis of 123 alcoholic patients with a median of 7 years follow-up at one center. In addition to alcohol, 43 (35%) patients had another possible factor contributing to cirrhosis. Actuarial patient and graft survival rates were, respectively, 84% and 81% (1 year); 72% and 66% (5 years); and 63% and 59% (7 years). After transplantation, 18 patients (15%) manifested 21 noncutaneous de novo malignancies, which is significantly more than controls (P=0.0001); upper aerodigestive squamous carcinomas were overrepresented (P=0.03). Thirteen patients had definitely relapsed and three others were suspected to have relapsed. Relapse was predicted by daily ethanol consumption (P=0.0314), but not by duration of pretransplant sobriety or explant histology. No patient had alcoholic hepatitis after transplantation and neither late onset acute nor chronic rejection was significantly increased. Multiple regression analyses for predictors of graft failure identified major biliary/vascular complications (P=0.01), chronic bile duct injury on biopsy (P=0.002), and pericellular fibrosis on biopsy (P=0.05); graft viral hepatitis was marginally significant (P=0.07) on univariate analysis. Alcoholic liver disease is an excellent indication for liver transplantation in those without coexistent conditions. Recurrent alcoholic liver disease alone is not an important cause of graft pathology or failure. Potential recipients should be heavily screened before transplantation for coexistent conditions (e.g., hepatitis C, metabolic diseases) and other target-organ damage, especially aerodigestive malignancy, which are greater causes of morbidity and mortality than is recurrent alcohol liver disease.

Late protection against chemical induced liver injury with dimethyl sulfoxide: [formula omitted], Dept. of Anesthesiology, University of Arizona, Tucson, AZ

The etiology of chronic bile duct injury and fibrosis in patients with autoimmune cholestatic liver diseases is complex, and likely involves immune cells such as lymphocytes. However, most models of biliary fibrosis are not autoimmune in nature. Biliary fibrosis can be induced experimentally by prolonged exposure of mice to the bile duct toxicant alpha-naphthylisothiocyanate (ANIT). We determined whether lymphocytes contributed to ANIT-mediated biliary hyperplasia and fibrosis in mice. Hepatic accumulation of T-lymphocytes and increased serum levels of anti-nuclear-autoantibodies were evident in wild-type mice exposed to ANIT (0.05% ANIT in chow). This occurred alongside bile duct hyperplasia and biliary fibrosis. To assess the role of lymphocytes in ANIT-induced biliary fibrosis, we utilized RAG1−/− mice, which lack T- and B-lymphocytes. ANIT-induced bile duct injury, indicated by increased serum alkaline phosphatase activity, was reduced in ANIT-exposed RAG1−/− mice compared to ANIT-exposed wild-type mice. Despite this reduction in biliary injury, ANIT-induced bile duct hyperplasia was similar in wild-type and RAG1−/− mice. However, hepatic induction of profibrogenic genes including COL1A1, ITGβ6 and TGFβ2 was markedly attenuated in ANIT-exposed RAG1−/− mice compared to ANIT-exposed wild-type mice. Peribiliary collagen deposition was also reduced in ANIT-exposed RAG1−/− mice. The results indicate that lymphocytes exacerbate bile duct injury and fibrosis in ANIT-exposed mice without impacting bile duct hyperplasia.