Sclerosing cholangitis epidemiology and etiology

Secondary sclerosing cholangitis as a complication of severe COVID-19: A case report and review of the literature

This case of secondary sclerosing cholangitis (SSC-CIP) emphasizes the need to provide follow-up care for patients that have recovered from COVID-19 in order to understand the complexity of SARS-CoV-2 associated sequela.

Pathophysiologic implications of innate immunity and autoinflammation in the biliary epithelium

The most studied physiological function of biliary epithelial cells (cholangiocytes) is to regulate bile flow and composition, in particular the hydration and alkalinity of the primary bile secreted by hepatocytes. After almost three decades of studies it is now become clear that cholangiocytes are also involved in epithelial innate immunity, in inflammation, and in the reparative processes in response to liver damage. An increasing number of evidence highlights the ability of cholangiocyte to undergo changes in phenotype and function in response to liver damage. By participating actively to the immune and inflammatory responses, cholangiocytes represent a first defense line against liver injury from different causes. Indeed, cholangiocytes express a number of receptors able to recognize pathogen- or damage-associated molecular patterns (PAMPs/DAMPs), such as Toll-like receptors (TLR), which modulate their pro-inflammatory behavior. Cholangiocytes can be both the targets and the initiators of the inflammatory process. Derangements of the signals controlling these mechanisms are at the basis of the pathogenesis of different cholangiopathies, both hereditary and acquired, such as cystic fibrosis-related liver disease and sclerosing cholangitis. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

Macrophage Depletion Attenuates Extracellular Matrix Deposition and Ductular Reaction in a Mouse Model of Chronic Cholangiopathies

Chronic cholangiopathies, such as primary and secondary sclerosing cholangitis, are progressive disease entities, associated with periportal accumulation of inflammatory cells, encompassing monocytes and macrophages, peribiliary extracellular matrix (ECM) deposition and ductular reaction (DR). This study aimed to elucidate the relevance of macrophages in the progression of chronic cholangiopathies through macrophage depletion in a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) mouse model. One group of mice received a single i.p. injection of Clodronate encapsulated liposomes (CLOLipo) at day 7 of a 14 day DDC treatment, while control animals were co-treated with PBSLipo instead. Mice were sacrificed after 7 or respectively 14 days of treatment for immunohistochemical assessment of macrophage recruitment (F4/80), ECM deposition (Sirius Red, Laminin) and DR (CK19). Macrophage depletion during a 14 day DDC treatment resulted in a significant inhibition of ECM deposition. Porto-lobular migration patterns of laminin-rich ECM and ductular structures were significantly attenuated and a progression of DR was effectively inhibited by macrophage depletion. CLOLipo co-treatment resulted in a confined DR to portal regions without amorphous cell clusters. This study suggests that therapeutic options selectively directed towards macrophages might represent a feasible treatment for chronic cholestatic liver diseases.

Isolated Mass-Forming IgG4-Related Cholangitis as an Initial Clinical Presentation of Systemic IgG4-Related Disease

IgG4-related disease (IgG4-RD) may involve multiple organs. Although it usually presents as diffuse organ involvement, localized mass-forming lesions have been occasionally encountered in pancreas. However, the same pattern has been seldom reported in biliary tract. A 61-year-old male showed a hilar bile duct mass with multiple enlarged lymph nodes in imaging studies and he underwent trisectionectomy under impression of cholangiocarcinoma. Gross examination revealed a mass-like lesion around hilar bile duct. Histopathologically, dense lymphoplasmacytic infiltration and storiform fibrosis were identified without evidence of malignancy. Immunohistochemical stain demonstrated rich IgG4-positive plasma cell infiltration. Follow-up imaging studies disclosed multiple enlarged lymph nodes with involvement of pancreas and perisplenic soft tissue. The lesions have been significantly reduced after steroid treatment, which suggests multi-organ involvement of systemic IgG4-RD. Here, we report an unusual localized mass-forming IgG4-related cholangitis as an initial presentation of IgG4-RD, which was biliary manifestation of systemic IgG4-related autoimmune disease.

Segmental cholangiectasia clinically worrisome for cholangiocarcinoma: comparison with recurrent pyogenic cholangitis

The aim of this study was to review the clinical, radiographic, and pathologic features of cases of benign segmental cholangiectasia in non-Asian US patients with clinical concern for cholangiocarcinoma and compare these features with cases of recurrent pyogenic cholangitis (RPC) in Asian patients. A total of 10 non-Asian US patients with benign segmental cholangiectasia were included in this study. Nine of them underwent partial hepatic resection due to cholangiographic findings of segmental cholangiectasia with mural thickening and/or proximal biliary stricture. One was found to have markedly dilated and thickened intrahepatic bile ducts at the time of autopsy. Clinical and radiographic findings were reviewed. Elastin stains and immunostains for immunoglobulin G4, cluster of differentiation (CD1a), and Langerin were performed. Six comparison cases of RPC in Asian US patients were also examined. Histologic examination of resection specimens revealed markedly dilated large intrahepatic bile ducts with variable degrees of mural fibrosis, periductal gland hyperplasia, inflammation, and liver parenchymal atrophy. These changes were not associated with a ductular reaction. There was no evidence of biliary dysplasia or biliary cirrhosis in any cases. No gross or microscopic feature definitively separated the Asian from non-Asian patients. The etiology of this disorder in non-Asian US patients is unclear. It does not appear to represent a localized variant of Caroli disease or primary sclerosing cholangitis. The high degree of similarity shared by these cases and classic RPC suggests a common pathogenic mechanism, although the pathologic features tend to be less well developed in the cases from the non-Asian US patients.

Bone marrow transplantation demonstrates medullar origin of CD34+ fibrocytes and ameliorates hepatic fibrosis in Abcb4-/- mice

Bone marrow (BM)-derived stem cells and CD34(+) fibrocytes are associated with fibrogenesis in several organs. In an Abcb4(-/-) mouse model for sclerosing cholangitis alpha-smooth muscle actin-positive (alpha-SMA(+)) myofibroblasts are thought to play a pivotal role in hepatic fibrogenesis. The aim of this study was 2-fold: (1) to demonstrate that the origin of an important fibrogenetic cell population is the BM; and (2) to investigate whether transplantation of BM (BM-Tx) affects liver function, staging, and grading. Surrogate markers for fibrogenesis and regulation of hepatic stellate cells (HSC) as well as progenitor-cell-derived fibrocytes in liver tissue were analyzed by quantitative real-time polymerase chain reaction (PCR) and immunohistology. After lethal irradiation of recipient mice, BM-Tx was carried out by way of tail vein injection of BM cells from marker protein donors (green fluorescent protein, GFP(+)) or Abcb4(-/-) mice as control (syngeneic Tx). Parameters of liver function were assessed serologically and histologically. Activated HSC of alpha-SMA(+)/CRP2(+) phenotype were expressed in approximately 50% of proliferating bile ducts, whereas fibrotic liver parenchyma showed no expression thereof. Epithelial mesenchymal transfer (EMT) was visualized in the areas of proliferating bile ducts. The hematopoietic origin of CD34(+) fibrocytes was demonstrated immunohistologically in livers of BM chimeric mice. These CD34(+) cells infiltrated hepatic lobules from portal fields and developed a desmin(+) phenotype expressing collagen type I in fibrotic parenchyma as well as in vitro after isolation by magnetic cell separation. Transplantation of GFP(+)/Abcb4(+) BM improved liver function and staging compared with sham transplantation, but no significant differences were noticed among allogeneic and syngeneic Tx.

CONCLUSION

The present study is the first to identify that both BM-derived fibrocytes and HSC are involved in biliary fibrogenesis in Abcb4(-/-) mice. Our data suggest that changes in immunity subsequent to BM-Tx may alter hepatic fibrosis.

Incidence, clinical presentation and pathological features of benign sclerosing cholangitis of unknown origin masquerading as biliary carcinoma

BACKGROUND

Benign obstructions of the liver hilum are occasionally encountered in surgically resected cases. Some of these cases are pathologically classified as benign sclerosing cholangitis and are not clearly categorized. This study aims to elucidate the clinicopathological features of benign sclerosing cholangitis of unknown origin.

METHODS

Patients who had undergone surgery of the proximal bile duct from 1993 to 2008 on suspicion of proximal bile carcinoma were evaluated, then their clinical presentation, histopathological and immunohistochemical findings were retrospectively analyzed.

RESULTS

One hundred seventy-six patients underwent surgery during this period. Of these, five patients were diagnosed with benign sclerosing cholangitis of unknown origin. All five patients were middle-aged with no history of autoimmune disease. One patient died of recurrent cholangitis after surgery. Histopathologically, lymphoplasmacytic infiltrations were observed in all five cases. Among them, the clinicopathological findings of one patient were compatible with IgG4-related sclerosing cholangitis, and the other two patients had unusual histopathological findings with prominent lymph follicular formation.

CONCLUSIONS

Although patients with benign sclerosing cholangitis of unknown origin comprise a heterogeneous population, they can be further classified into subgroups. The response to immunosuppressive therapy, long-term prognosis and histological morphology of the disease should be considered in order to classify these cases of sclerosing cholangitis.