Large Intrahepatic Ducts Research Articles

Síndrome de Caroli em um cão

ABSTRACT: Caroli syndrome is characterized by a combination of intrahepatic biliary ductal ectasia and congenital ductal fibrosis due to the failure of involution of ductal plates and large intrahepatic ducts. This study aims to report Caroli syndrome in a dog, with emphasis on clinical characteristics, complementary examinations, and diagnostic approach. A 1-year-old mixed-breed intact male dog was presented with a 7-day history of acute vomiting and anorexia. Clinical evaluation revealed severe jaundice, abdominal pain, dehydration, lethargy, and abdominal distension. Ultrasonography revealed hepatic cysts filled with fluid. Exploratory laparotomy was performed to clarify the imaging findings; however, the dog died shortly after surgery. Postmortem examination revealed that the liver was reduced in size and had multiple interconnected and distended saccular dilations. The bile ducts were markedly dilated and replaced a large part of the liver parenchyma. Multiple small cysts were also observed in the kidneys. Microscopically, the hepatic lesions were characterized by extensive bridging fibrosis associated with proliferating and ectatic bile ducts contiguous with the biliary tree. Marked fibrosis and small cysts were observed in the kidneys. Therefore, a final diagnosis of Caroli syndrome was made. While uncommon, this syndrome should be considered as a differential diagnosis for young dogs with biliary cysts and hepatic fibrosis.

Functional heterogeneity of cholangiocytes.

The objective of this article is to summarize the findings related to the notion that cholangiocytes, within small and large intrahepatic ducts, are heterogeneous regarding (1) morphology; (2) secretion in response to hormones and peptides and to bile acids; and (3) proliferation in response to injury or toxins, including bile duct ligation (BDL), acute carbon tetrachloride (CCl 4 ) administration, chronic feeding of bile salts (i.e., taurocholate [TC] or taurolithocholate [TLC]) or alpha-naphthylisothiocyanate (ANIT). After an overview of the morphology of the biliary epithelium, we provide a summary of cholangiocyte function, the in vivo models, and the in vitro experimental tools (i.e., small and large cholangiocytes or small and large intrahepatic bile duct units [IBDU]), which allowed us to demonstrate cholangiocyte heterogeneity. After a discussion on the receptors, transporters, and channels that are heterogeneously expressed by cholangiocytes, we discuss the different-sized ducts that differentially respond to injury and toxins. Finally, we review the human diseases that selectively target specific-sized ducts.

Primary sclerosing cholangitis in children.

Primary sclerosing cholangitis (PSC), a chronic inflammatory process affecting the extrahepatic and/or medium to large bile ducts, is not rare in children. It has features suggesting an autoimmune pathogenesis, although the mechanism of tissue damage remains unknown. The clinical presentation of childhood primary sclerosing cholangitis is highly variable and frequently without obvious features of cholestasis. Clinical similarity to autoimmune hepatitis is common. Association with chronic colitis is less common than in adults. Cholangiography is essential for the diagnosis and examination of the medium to large intrahepatic ducts is mandatory, as 40% of children lack extrahepatic duct involvement. Histological findings may help to distinguish childhood PSC from autoimmune hepatitis. In children, sclerosing cholangitis may also develop secondary to other disease processes, notably Langerhans histiocytosis, congenital immunodeficiencies and cystic fibrosis. Neonatal sclerosing cholangitis is chronic inflammatory disease of bile ducts which presents initially with neonatal cholestasis; its pathogenesis remains uncertain and may not be the same as for primary sclerosing cholangitis. Effective treatment modalities for childhood PSC remain undetermined. Liver transplantation is required for children who progress to biliary cirrhosis and hepatic decompensation.

Radiological and pathological features of AIDS-related polypoid cholangitis

A review of the radiographs obtained at ERCP from 31 patients with AIDS-related sclerosing cholangitis (ARSC) demonstrated intraluminal polypoidal defects within the common bile duct and larger intrahepatic ducts in eight cases (26%). The radiological features from this subgroup are described and correlated with the microbiological and histological findings from biopsy specimens including two patients who underwent post-mortem examination. At microscopy the polypoid lesions were demonstrated to consist of granulation tissue. The presence of these polyps did not adversely affect the prognosis nor were they associated with any particular infective agent. We propose recognizing the existence of this entity by the term AIDS-related polypoid cholangitis (ARPC).

AIDS-related cholangiopathy

Several types of biliary tract abnormality of undetermined origin have been described among AIDS patients. The aims of this study are: (1) to evaluate whether biliary tree involvement is in fact one or several homogeneous morphological entities, (2) to specify the role of CMV or Cryptosporidium sp. infection, and (3) to evaluate the possible efficacy of treatment. Since ultrasound had revealed abnormality in the biliary tree, 26 consecutive AIDS patients underwent cholangiography. Cholangiograms enabled us to distinguish between two types of biliary tract involvement: (1) gradual and regular stenosis of the terminal portion of the common bile duct associated with dilation but without irregularity of the intrahepatic biliary ducts was present in 27% of our cases, and (2) distal stenosis of the extrahepatic biliary ducts combined with diffuse irregularity of the caliber of the intrahepatic bile ducts was present in 73% of our cases. Concomitant infection by CMV or Cryptosporidium sp. was significantly more frequent when intrahepatic duct irregularities were present (94%) than when absent (14%, P < 0.001). Anti-CMV treatment and sphincterotomy were unsuccessful in treating anomalies of the intrahepatic biliary tract. Conversely, sphincterotomy caused rapid and lasting disappearance of pain in all our patients. In conclusion, biliary tract involvement in AIDS patients is of two types. CMV infection and infection by Cryptosporidium sp. are most frequent when the large intrahepatic ducts are implicated.

The spectrum of bile duct lesions in end‐stage primary sclerosing cholangitis

Tissue from 15 livers with primary sclerosing cholangitis, obtained at transplantation, was examined histologically with respect to: small and medium sized bile duct lesions; large bile duct lesions; fibrosis/cirrhosis; and parenchymal changes. Lesions affecting small and medium-sized bile ducts were quantified by determining the percentage of 20 portal tracts involved. The two characteristic bile duct lesions of primary sclerosing cholangitis, periductal fibrosis and fibro-obliterative scars, were largely confined to medium-sized portal areas. Although present in each case, the number of such lesions varied considerably. Loss of bile ducts was the most conspicuous feature in small portal tracts where the diagnostic duct lesions of primary sclerosing cholangitis were rarely observed. Inflammation, ulceration and cholangiectases of large intrahepatic ducts were common, and appear to be useful additional diagnostic features.

The Relation Between Structure and Function of Bile Ducts in Man, Some Laboratory Animals and the Adelie Penguin

The biliary trees of man, dog, cat, rabbit, rat, guinea pig and penguin were examined in histological sections and by latex casts. The trees of man, dog, and cat were similar with only minor differences. Tubulo-alveolar glands were present in all three species around large intrahepatic ducts and in large portal tracts there were zones of ductules (areas with many small bile ducts), surrounded by small vessels with no apparent relation to hepatocytes. Both these features were present in the guinea pig and tubulo-alveolar glands were present in the penguin liver. The biliary epithelium of the rat was comparatively simple but that of the rabbit appeared to be highly specialized. An estimation of the complexity of the biliary tree was obtained in the mammals by comparing the circumference of small portal venous branches with the circumference of the accompanying bile ducts, and obtaining a ratio. Man, dog, and cat had fewer and smaller bile ducts than the other species. The literature on the rate of formation and composition of bile in the species studied here was reviewed and it appears that the physiology of bile secretion can be related to the morphology of the biliary tree.