Inflammatory responses to Opisthorchis viverrini infection in animal models: A comparison between susceptible and nonsusceptible hosts in different anatomical locations

Background

Inflammation caused by Opisthorchis viverrini infection increases the risk of cholangitis, cholecystitis, and leads to bile duct cancer (cholangiocarcinoma or CCA). However, only certain infected individuals are susceptible to CCA, suggesting the involvement of host factors in cancer development. In addition, there are reports indicating differences in the locations of CCA.

Aim

This study aims to investigate cellular inflammatory responses in the common bile duct (CB), intrahepatic bile duct (IHB), and gallbladder (GB) in susceptible and non-susceptible hosts following O. viverrini infection.

Methods

Thirty Syrian golden hamsters (a susceptible host) and 30 BALB/c mice (a non-susceptible host) infected with O. viverrini were studied at six time points (five animals per group). Histopathological evaluations were conducted on samples from the IHB, CB, and GB. Inflammatory cell infiltration was quantitatively assessed and compared between groups and time points. Statistical analysis was performed using one-way ANOVA, with a significance level of p < 0.05.

Results

Inflammation was significantly more pronounced in the IHB compared to the other two biliary locations. In comparison between susceptible and non-susceptible hosts, the intensity of inflammation was higher in the OV+H group than in the OV+M group (p < 0.05).

Conclusion

This study highlights the association between host response to inflammation, tissue location, and host susceptibility, with the IHB showing particular susceptibility to inflammation and pathological changes. These findings contribute to our understanding of the increased risk of CCA in susceptible hosts.

Inflammatory cell responses in biliary mucosa during Opisthorchis viverrini infection: Insights into susceptibility differences among hosts

Background

Individual host susceptibility is believed to be a risk factor in the interaction between the host and the parasite. Since studying time series in humans is limited, animal models are replaced.

Aim

This study aims to explore and compare the pattern of inflammatory cell types along the biliary tract and their association with proliferative lesions in the early development of cholangiocarcinoma from susceptible and nonsusceptible animal models.

Methods

Thirty male Syrian golden hamsters and 30 BALB/c mice, serving as the susceptible and nonsusceptible animal models, were used in this comparative study. The animals were infected with 50 Opisthorchis viverrini metacercariae via gastric intubation. At days 1, 2, 7, 14, 28, and 56 postinfection (p.i.), five animals were randomly selected from each group and humanely sacrificed. The hepatobiliary tissues were collected and processed for histopathological study. Histochemical and immunohistochemical staining were applied to differentiate the inflammatory cell types. Kruskal-Wallis and Mann-Whitney tests were applied to assess all semi-quantitative and quantitative variables. The correlation between each variable was also analyzed using Spearman rank at a p-value < 0.05.

Results

The results demonstrated that mice had different patterns of infiltrating cell types when compared to hamsters. This suggested that the cellular response to the infection in mice occurred earlier than that in hamsters. The response in mice reached its peak at D7 to D14 and then rapidly declined at D28. In contrast, although the inflammatory response in hamsters started slowly, the response reached the peak at D28 and maintained a high level until D56. Significant differences in the number of inflammatory cells between mice and hamsters were seen at D1 (p = 0.047), D7 (p = 0.049), D28 (p = 0.040), and D56 (p < 0.040).

Conclusion

The inflammatory responses to O. viverrini infection in the nonsusceptible animal model occurred and declined earlier while the response in the susceptible animal model occurred later in a gradual manner. Both rodents are suitable animal models for the studies of opisthorchiasis susceptibility.

Cholangiocarcinoma in a Free-Ranging Eurasian Brown Bear (Ursus arctos arctos) from Northern Spain

A hepatic cholangiocarcinoma with metastases in the gallbladder, left elbow joint, adrenal glands, and lungs was observed in a female 21-yr-old free-ranging Eurasian brown bear (Ursus arctos arctos) found in the Principality of Asturias (northern Spain). Gross and histopathologic findings are described.

Feline hepatobiliary neoplasia and mistaken age

A cat, thought to be 5 years old, and with reduced appetite and weight loss, was presented for dental cleaning and extractions. Bile duct origin hepatic carcinoma was diagnosed. The progression of iris degeneration, dental disease, histological renal lesions, spondylosis, and hepatobiliary neoplasia suggest this cat was closer to 10 years old.

Papillary Adenocarcinoma of the Extrahepatic Bile Duct in a Holstein Cow

A 15-year-old female Holstein cow was presented with a history of anorexia and weight loss. Abnormal physical examination findings included poor body condition, dehydration, icterus, and photodermatitis on nonpigmented areas of the skin of the dorsum. At necropsy, the common bile duct was greatly enlarged, with thickened walls, and tightly adhered to the hepatic capsular surface and serosa of adjacent loops of the small intestine. Two sessile, yellowish, friable, well-circumscribed, cauliflower-like, bulging masses (14 and 8 cm in diameter) were attached to the inner surface of the common bile duct blocking its lumen. Microscopically, the tumor was composed of well-differentiated, columnar epithelial cells with oval or round, vesicular, basal nuclei arranged in papillary projections. Periodic acid-Schiff-positive material accumulated in the apical cytoplasm of the neoplastic cells. Immunostaining of the tumor cells was positive for cytokeratin (CK) of wide-spectrum screening and for CK 7. The diagnosis of papillary adenocarcinoma of the extrahepatic bile duct was based on the morphologic features of the neoplasm and evidence of local invasion. To the best of our knowledge, extrahepatic bile duct carcinomas have not been described in cattle.

Diagnostic criteria for proliferative hepatic lesions in brown bullhead Ameiurus nebulosus

Brown bullhead Ameiurus nebulosus is used as indicator species for contaminant effects at areas of concern (AOC) in the Great Lakes and other areas. One of the beneficial use impairments at numerous AOC is 'fish tumors and other deformities'. An impairment occurs when the prevalence of fish tumors and other deformities exceeds those at unimpacted or control sites or when survey data confirm the presence of neoplastic or preneoplastic liver lesions in bullhead or white sucker Catostomus commersonii. Numerous surveys have been conducted over the years assessing neoplasia in these fishes, both liver and skin tumors. However, a major problem in comparing the results has been a lack of consistent criteria for evaluating histological changes in bullhead livers. As individual AOC develop and implement remedial action plans, realistic and attainable delisting targets need to be specified. For this to occur and be consistent from site to site there must be standardization of the criteria being used to evaluate specific impairments. In this report, specific diagnostic criteria are provided for both non-neoplastic and neoplastic proliferative hepatocellular and biliary lesions. These criteria should assist fish pathologists in describing and categorizing proliferative liver lesions from brown bullhead.

Bile duct carcinoma and nasal adenocarcinoma in a guinea pig

A guinea pig with a low grade bile duct carcinoma and nasal papillary adenocarcinoma also had a collagen nevus or lipoma that was considered insignificant in the overall management of the case. The bile duct carcinoma was treated successfully through surgery. The clinical presentation of the adenocarcinoma, which was not treated, is described.

Hepatocellular adenoma in a 12-year-old crossbred German shepherd dog

A 12-year-old, neutered male crossbred German shepherd presented with lethargy, inappetence, vomiting, and diarrhea. Bile duct carcinoma was diagnosed by cytological analysis of samples obtained by ultrasound-guided fine-needle aspiration. After surgical excision of the mass, the histologic diagnosis was hepatocellular adenoma.

Sporadic neoplasms of farmed chinook salmon, Oncorhynchus tshawytscha (Walbaum), from New Zealand

Eight separate neoplasms with five distinct morphologies are described in the present report. The spontaneous neoplasms were identified in farmed chinook salmon, Oncorhynchus tshawytscha (Walbaum), during processing. The masses were examined histologically and were classified as teratoma, rhabdosarcoma, biliary and renal cystadenomas, renal carcinoma and three leiomyomas. This represents one neoplasm detected for every 125000 fish processed during the sampling period.

Hepatic biliary adenofibroma: a hitherto unrecognized tumor in equines. Report of a case

Hepatic biliary cystadenoma is a well-delineated neoplasm in some domestic animals, especially in cats, but it has not been reported in equines. We report on a case of hepatic biliary tumor, incidentally found in a 10-year-old horse, with gross and microscopic features similar to those observed in biliary adenofibroma of humans. The tumor presented as a solid mass measuring 16 cm in diameter and histologically was composed of complex tubulocystic biliary components embedded in an abundant fibrotic stroma. We regarded this tumor as a morphological variant of biliary cystadenoma of domestic animals. Differential diagnoses from other hepatic biliary tumor-like and tumor lesions are provided.

Hepatobiliary inflammation, neoplasia, and argyrophilic bacteria in a ferret colony

Hepatobiliary disease was diagnosed in eight of 34 genetically unrelated cohabitating pet ferrets (Mustela putorios furo) during a 7-year period. The eight ferrets ranged in age from 5 to 8 years and exhibited chronic cholangiohepatitis coupled with cellular proliferation ranging from hyperplasia to frank neoplasia. Spiral-shaped argyrophilic bacteria were demonstrated in livers of three ferrets, including two with carcinoma. Sequence analysis of a 400-base pair polymerase chain reaction product amplified from DNA derived from fecal bacteria from one ferret demonstrated 98% and 97% similarity to Helicobacter cholecystus and Helicobacter sp. strain 266-1 , respectively. The clustering of severe hepatic disease in these cohabitating ferroes suggests a possible infectious etiology. The role of Helicobacter species and other bacteria in hepatitis and/or neoplasia in ferrets requires further study.

Immunohistochemical characterization of canine hyperplastic hepatic lesions and hepatocellular and biliary neoplasms with monoclonal antibody hepatocyte paraffin 1 and a monoclonal antibody to cytokeratin 7

Immunostaining with monoclonal antibody (MoAb) hepatocyte paraffin 1 (Hep Par 1) and an MoAb to cytokeratin 7 (CK7) was performed on 105 formalin-fixed, paraffin-embedded canine hyperplastic and neoplastic hepatic lesions. Hep Par 1 was detected in 12/12 hyperplastic nodules, 17/17 hepatocellular adenomas, and 37/40 hepatocellular carcinomas. The staining was disseminated, granular, and cytoplasmic. This antibody did not react with normal or neoplastic biliary epithelium. Other hepatic tumors or tumors metastatic to the liver did not bind Hep Par 1 except one metastatic intestinal carcinoma. MoAb to CK 7 stained all hyperplastic biliary epithelium and benign cholangiocellular tumors (5/5) and 14/18 cholangiocellular carcinomas. One hepatocellular carcinoma had cells positive for both Hep Par 1 and CK 7. Liver was the only normal tissue tested that reacted with MoAb Hep Par 1. Only five nonhepatic tumors (one adrenocortical carcinoma, one interstitial cell tumor of the testis, one melanoma, and two salivary adenocarcinomas) of 277 tumors tested had focal/multifocal staining for Hep Par 1. Prolonged fixation did not alter the staining with Hep Par 1. We conclude that Hep Par 1 is a specific and sensitive marker for canine hepatocellular tumors and allows distinction between hepatocellular and biliary neoplasms.

Concurrent cholangiocarcinoma, peritonitis, paratuberculosis, and aspergillosis in a goat

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Cholangiocarcinoma with metastasis in a captive Adelie penguin (Pygoscelis adeliae)

A captive male Adelie penguin (Pygoscelis adeliae), wild caught in 1976, died unexpectedly. Necropsy revealed cholangiocarcinoma with metastases to lung, pancreas, mesentery, and cloaca, the first known case of a penguin hepatic tumor.

Combined hepatocellular and cholangiocellular carcinoma in a dog

A transitional type of combined hepatocellular and cholangiocellular carcinoma developed in a 12-year-old male Yorkshire terrier dog. The tumor was histologically composed of both hepatocellular carcinoma and cholangiocellular carcinoma components, and both elements were closely intermingled. Intraluminal mucin accumulation in cytokeratin-positive tubular/glandular structures was observed within the cholangiocellular carcinoma components and this feature was useful histological marker for a differential diagnosis between combined hepatocellular and cholangiocellular carcinoma and a pseudoglandular type of hepatocellular carcinoma. This primary hepatic tumor is extremely rare in dogs.

Ultrasonographic evaluation of biliary cystadenomas in cats

The purpose of this study was to describe the ultrasonographic appearance of biliary cystadenomas in cats and compare the findings to a similar rare form of liver tumor in humans. Biliary cystadenomas are uncommon, benign liver tumors of older cats that may occur as focal or multifocal cystic lesions within the liver. The records of 10 cats which had abdominal ultrasonography and histologic diagnosis of biliary cystadenoma were reviewed. The average age of affected cats was 13.3 years (range 10-16 years). Eight cats were neutered males and two were neutered females. In three cats, the tumors were not seen ultrasonographically due to their small size or from being obscured by near-field reverberation echoes. The remaining seven cats had solitary (4 cats) or multifocal (3 cats) masses corresponding to variable ultrasonographic patterns: multilocular masses containing thin-walled cysts, hyperechoic masses with cystic components, or masses of mixed echogenicity with cystic components. The masses had variable ultrasonographic patterns when multifocal disease was present. Recognizable cysts were evident somewhere within the tumors seen ultrasonographically, although sometimes the cysts appeared very small. The biliary cystadenomas were thought to be clinically silent. Although liver enlargement or a cranial abdominal mass was palpable in 4 cats, no consistent trend of clinical signs, CBC or serum biochemical abnormalities could be directly attributed to biliary cystadenoma. The treatment of choice is surgical resection of the tumor, as continued growth may compress adjacent vital structures within the liver. The differential diagnosis of biliary cystadenomas from other cystic liver lesions such as hepatic cysts, hematomas, abscesses, parasitic cysts, or other liver tumors is discussed.

Sclerosing adenocarcinoma of the extrahepatic bile duct in a cat

Sclerosing adenocarcinoma of the extrahepatic bile duct and pyometra were diagnosed in a 17-year-old entire female Siamese cat which had had anorexia, depression, acute icterus and abdominal distension for about a week. Clinical signs derived from he tumor were minimal and non-specific until the diffuse thickening of the bile duct obstructed bile flow and acute icterus resulted. Sclerosing adenocarcinoma of the extrahepatic bile duct is a human variant of bile duct carcinomas that has not, to the authors' knowledge, previously been described in the cat, but it appears to be as invasive as other feline hepatic tumours.

The riddle of hepatic neoplasia in brown bullheads from relatively unpolluted waters in New York State

Since 1985, pathologists at Cornell University have investigated the causes of lesions in freshwater fish throughout New York waters in order to clarify possible impairment of fish health by environmental contaminants. Fishermen and biologists alerted us to several relatively protected reservoirs and ponds in which we have found no evidence of elevated levels of anthropogenic environmental contaminants but in which up to 100% of brown bullheads exhibited skin neoplasia. Complete necropsies and histologic study revealed that over 30% of mature brown bullheads from some of these sites had benign or malignant hepatocellular or biliary liver neoplasia. Up to 50% of brown bullheads had benign or malignant liver neoplasia in other relatively unpolluted waters with no evidence of skin neoplasia in bullheads. Multiple samplings of brown bullheads from several of these sites have revealed puzzling variability in the prevalence of skin, liver, and other neoplasia in these fish populations. The cause of these striking epizootics of neoplasia in brown bullheads in unpolluted waters in New York State remains unclear. We hypothesize that natural carcinogens such as N-nitroso compounds formed in aquatic sediments or radon from geologic formations may contribute to epizootic fish neoplasia in New York waters.

Biliary cystadenoma of cats

Published surveys of feline neoplasia have not specifically included biliary cystadenoma, and there is only one case report in the literature. This report is a compilation of 13 feline cases and provides a description of clinical, pathologic, immunohistochemical, and ultrastructural aspects of biliary cystadenoma as well as a discussion of comparative pathology of biliary cystadenoma in human beings and speculative histogenesis.

Septic cholangiohepatitis and cholangiocarcinoma in a horse

Septic cholangiohepatitis was diagnosed in an 11-year-old Warmblood gelding with a history of intermittent colic and fever. Klebsiella pneumoniae, susceptible to gentamicin, was cultured from the biopsy specimen. However, treatment with gentamicin was unsuccessful, and histologic examination and bacteriologic culture of a biopsy specimen obtained 3 weeks later revealed progression of the hepatic inflammation and yielded growth of gentamicin-resistant K pneumoniae. At this time, several discrete hyperechoic structures, suggestive of biliary calculi, were seen ultrasonographically. A change in antibiotic treatment was associated with gradual resolution of clinical signs. Five months after initial examination, the horse had a sudden onset of severe right forelimb lameness. The horse responded to treatment with antibiotics and phenylbutazone, but lameness and fever that was unresponsive to treatment recurred 7 months later, and the horse was euthanatized. Necropsy revealed nodules throughout the liver and a mass associated with the right metacarpophalangeal joint. Histologic and immunohistochemical examination revealed carcinomatous infiltration of the liver and metacarpophalangeal joint. The tumor was probably of biliary origin. Carcinoma should be considered in cases of septic cholangiohepatitis unresponsive to antibiotic treatment.

Acquired myasthenia gravis and cholangiocellular carcinoma in a dog

Acquired myasthenia gravis and cholangiocellular carcinoma were diagnosed in a 7-year-old English Setter referred because of forelimb lameness, exercise-induced weakness, and fever. Three months earlier, the dog had had a pleuropulmonary infection caused by a Fusobacterium sp. The concurrent development of myasthenia gravis and cholangiocellular carcinoma in this dog may be explained by a paraneoplastic syndrome, although it is unproven. The cholangiocellular carcinoma may have possessed an acetylcholine receptor-like antigen on the tumor surface, which induced autoantibodies to cross-react with acetylcholine receptors at the neuromuscular junction.

Cholangiocarcinoma in a 4-month-old double yellow-cheeked Amazon parrot (Amazona autumnalis)

A cholangiocarcinoma was diagnosed in a 4-month-old double yellow-cheeked Amazon parrot (Amazona autumnalis). Histologically, neoplastic cells effaced hepatocellular architecture. Ultrastructurally, variably dilated bile ductules were lined by simple cuboidal to low columnar ciliated epithelial cells with sparse cellular organelles and prominent junctional complexes. Elongated single cilia arising from basal bodies in the apical cytoplasm were occasionally evident. The presence of such a neoplasm in a 4-month-old parrot is extremely unusual.

Hyperplastic and neoplastic alterations in the livers of white perch (Morone americana) from the Chesapeake Bay

White perch (Morone americana) sampled from 15 estuaries of the Chesapeake Bay contained a variety of hyperplastic and neoplastic alterations in their livers. The lesions were derived from bile ductular epithelium and/or hepatocytes. The biliary lesions consisted of hyperplasias and adenomas. The hepatocellular lesions consisted of focal populations of altered cells and neoplasms, of clear-cell and basophilic morphologic appearance. The hepatocellular lesions were conspicuous in the absence of the decreased amount of copper accumulation. In this respect, the cells comprising these lesions are reminiscent of cells from hepatocellular neoplasia in mice and rats resistant to accumulation of iron.

Metastasis of bile ductule carcinoma in a cow

An 8-year-old Holstein cow was referred with a history of weight loss, poor milk production, and hyperfibrinoginemia. Laboratory evaluation showed high gamma-glutamyltransferase activity, prolonged sulfobromophthalein clearance half-time, and prolonged prothrombin and partial thromboplastin times. Multiple firm nodules with histologic evidence of bile ductule carcinoma were found on exploratory laparotomy and liver biopsy. Pulmonary and lymph node tumor metastases were extensive. Tumor development in this case could not be associated with any of the known contributing factors in ruminants. This case demonstrates the extensive metastatic potential of this tumor and nonspecific signs with which bovine hepatic disease can be manifested.

Tumors in dwarf galagos (Galagoides demidovii)

Three spontaneously occurring tumors are described in dwarf galagos. One tumor was a subcutaneous fibrous histiocytoma in the left inguinal area of an adult male; the other two were bile duct carcinomas in a seven-year-old male and a four-year-old female. Both bile duct carcinomas had remarkable invasive and metastasizing capacities.

Extrahepatic biliary carcinoma in sloth bears

Extrahepatic biliary carcinoma was found in each of 5 adult sloth bears that died between 1970 and 1984 while on exhibit in Ohio zoos. The tumor was characterized by numerous mucin-producing neoplastic glands scattered throughout abundant fibrous stroma. The cause of the tumor was not determined.

Canine biliary carcinoma: epidemiological comparisons with man

A retrospective study of abstracted data representing 1.1 million hospital examinations of dogs at veterinary university teaching facilities identified 77 with bile duct carcinoma. Using the hospital population, based on patient years at risk, as the expected frequency of particular zoographic characteristics, there was a suggestion of a familial (breed) predisposition in Labrador retrievers and limited evidence of a sex differential. Because mongrel dogs displayed about the same frequency of bile duct cancer as all breeds combined, other causal factors, besides genetics, are implied. A possible association was detected between canine cholangiocarcinoma and host infection by canine hookworms and/or whipworms. Human infection from hookworms (Necator americanus) and whipworms (Trichuris trichiura) is common in the southern rural areas of the U.S.A. (e.g. Appalachia), and tropical and sub-tropical countries of Africa, Central and South America, where there have been unexplained high rates reported for human biliary cancer. It is possible that the presence of these blood-letting nematodes, like a number of other parasites (ascarids, flukes and protozoa), may be related to the occurrence of human cholangiocarcinoma.

Canine bile duct carcinoma

Twenty-four adenocarcinomas of the hepatobiliary system were found among 110 primary hepatic neoplasms: 22 of these were intrahepatic, one involved the extrahepatic bile duct and one the gall bladder. Histologically, 10 intrahepatic neoplasms were classified as cholangiocarcinoma, and 12 as bile duct cystadenocarcinoma. The former were characterized by tubular structures lined by anaplastic cuboidal or columnar cells with diffuse fibrous stroma, and the latter by multiple cystic structures with papillary and solid areas. Half the bile duct cystadenocarcinomas showed benign cysts and transition to adenocarcinomas. This was seen in only one case of cholangiocarcinoma. The extrahepatic bile duct carcinoma was characterized by tubular structures lined with flattened cuboidal cells with scant stroma. The gall bladder adenocarcinoma contained many acinar structures lined with columnar or cuboidal cells and separated by thin stroma. Distant metastasis was found in 87.5% (21 of 24) sites of metastasis.

Extrahepatic biliary carcinomas in Asiatic bears

Extrahepatic biliary carcinomas occurred in 2 Asiatic bears at the National Zoological Park in Washington, D.C. The tumors were associated with ascites in both cases and jaundice in 1 and metastasized widely. Neither bear had gallstones. Microscopically, the tumors were infiltrative, scirrhous adenocarcinomas that produced varying amounts of mucin. A genetic predisposition and change from the natural diet were factors proposed to contribute to the development of this neoplasm.