In PSC with colitis treated with UDCA, most colonic carcinomas develop in the first years after the start of treatment.

BACKGROUND: Patients with PSC and IBD have a high incidence of colonic carcinomas (CRC), and the annual incidence of CRC increases with duration of disease. UDCA treatment has been suggested to reduce colonic dysplasias and carcinomas. AIMS: The annual incidence of colorectal carcinomas after long-term UDCA treatment was studied. METHODS: Patients included in a prospective study on the outcome after ursodeoxycholic acid (UDCA) treatment were evaluated. RESULTS: A total of 120 of 171 PSC patients included had IBD (108 UC and 12 CD). All patients were treated with UDCA for a median time of 6.7 years. Seven patients with PSC and IBD developed a CRC yielding a prevalence of 5.8%. In years 0-3 (n = 120) after the start of UDCA, the annual incidence rate of CRC was 0.62/100 patient years; in years 3-6 (n = 93) it increased to 1.28 and decreased thereafter in years 6-9 (n = 67) to 1.17, then in years 9-12 (n = 42) to 0 and after >12 years (n = 24) it remained 0. In PSC with IBD, Kaplan-Meier estimate of CRC formation increased with time in the first years of treatment and reached a plateau after 9 years; after treatment for ≥ 9 years, no further CRC were observed. CONCLUSION: After the start of UDCA, the annual incidence of CRC increased up to 6 years and subsequently decreased. In PSC with IBD treated with UDCA, most colonic carcinomas develop in the first years after the start of treatment.

Difficult diagnosis of a large cystic retroperitoneal tumor mimicking a hepatic origin.

Schwannomas are rare tumors, usually benign, originating from the nerve sheath, and found only infrequently in the retroperitoneal space. We report on a 67-year-old woman who was initially misdiagnosed and treated for a liver hydatid cyst. After incomplete resection and recurrence of the tumor, we were able to diagnose a large retroperitoneal schwannoma that completely displaced the liver to the left abdomen. The patient underwent surgical resection of the schwannoma; pathological evaluation revealed a cystic tumor measuring 18.5 × 18 × 12.5 cm, with tumor cells staining strongly positive for S-100. Retroperitoneal schwannomas may mimic cystic hepatic tumors and should, therefore, be considered as a differential diagnosis in such cases. We describe the diagnostic modalities and difficulties in the approach of a cystic liver tumor.

Mallory-Denk-bodies: lessons from keratin-containing hepatic inclusion bodies.

Inclusion bodies are characteristic morphological features of various neuronal, muscular and other human disorders. They share common molecular constituents such as p62, chaperones and proteasome subunits. The proteins within aggregates are misfolded with increased beta-sheet structure, they are heavily phosphorylated, ubiquitinylated and partially degraded. Furthermore, involvement of proteasomal system represents a common feature of virtually all inclusions. Multiple aggregates contain intermediate filament proteins as their major constituents. Among them, Mallory-Denk bodies (MDBs) are the best studied. MDBs represent hepatic inclusions observed in diverse chronic liver diseases such as alcoholic and non-alcoholic steatohepatitis, chronic cholestasis, metabolic disorders and hepatocellular neoplasms. MDBs are induced in mice fed griseofulvin or 3,5-diethoxycarbonyl-1,4-dihydrocollidine and resolve after discontinuation of toxin administration. The availability of a drug-induced model makes MDBs a unique tool for studying inclusion formation. Our review summarizes the recent advances gained from this model and shows how they relate to observations in other aggregates. The MDB formation-underlying mechanisms include protein misfolding, chaperone alterations, disproportional protein expression with keratin 8>keratin 18 levels and subsequent keratin 8 crosslinking via transglutaminase. p62 presence is crucial for MDB formation. Proteasome inhibitors precipitate MDB formation, whereas stimulation of autophagy with rapamycin attenuates their formation.

Is stenting necessary after balloon dilation of post-transplantation biliary strictures? Results of a prospective comparative study.

BACKGROUND AND STUDY AIMS: Biliary strictures are a major cause of morbidity following liver transplantation. In the present prospective comparative trial, we evaluated balloon dilation vs. balloon dilation plus stenting with regard to technical and clinical efficacy as well as complications. PATIENTS AND METHODS: A total of 32 patients with symptomatic biliary strictures after liver transplantation were assigned to balloon dilation (n = 17) or balloon dilation plus plastic stent placement (n = 15). The main outcome parameter was sustained clinical success defined as an interval of at least 3 months without further endoscopic intervention. Additional outcome parameters were assisted clinical success and treatment failure, as well as procedure-related complications. RESULTS: The initial technical success and primary clinical success rates in the dilation group were both 100%; in the stent group, the corresponding rates were 100% and 93% (n. s.). The sustained clinical success was 71% vs. 73%, respectively (n. s.). The time interval to reach sustained clinical success was 6.1 and 5.1 months, respectively (n. s.). No significant differences were found in assisted clinical success or in treatment failure. Complications were observed in 4.3% in the dilation group and 13.6% in the stent group (P < 0.05). Independent of the treatment group, a sustained clinical success in anastomotic strictures was achieved in 100%, whereas the success rate of strictures of the donor hepatic duct was 50% and of strictures involving the hilum, only 14% (P < 0.05). CONCLUSIONS: In patients with biliary strictures after liver transplantation, endoscopic balloon dilation alone was as effective as dilation plus stent placement. Stent placement was associated with a significantly higher complication rate. Endoscopic treatment of strictures of the biliary anastomosis is highly effective, whereas attempts to treat more complex strictures are less promising.

Poor outcome in progressive sclerosing cholangitis after septic shock.

BACKGROUND AND STUDY AIMS: Progressive sclerosing cholangitis after septic shock is an increasingly diagnosed disease entity. We evaluated the outcome after long-term follow-up of 29 patients treated in our institution between 1995 and 2007. PATIENTS AND METHODS: Patients with cholestatic liver disease without evidence of pre-existing hepatobiliary disease and who previously required long-term treatment in an intensive care unit for septic shock due to following reasons were included in the study: severe trauma (n = 10; five with burn injury and five following accident), cardiac operation (n = 9), bacterial infection (n = 5), sigmoidectomy (n = 2), operation of aortic aneurysm (n = 3). RESULTS: In all patients, endoscopic retrograde cholangiopancreatography showed multiple stenoses, pre-stenotic dilatations, and in part rarefication of intrahepatic small bile ducts. The bile ducts were partially filled by black-pigmented or necrotic material. In 18 of 29 patients, liver biopsies were performed and showed fibrosing cholangitis. The endoscopic therapy comprised removal of occluding material, dilation of stenoses, and intermittent stenting if necessary. All endoscopic procedures were done under antibiotic prophylaxis. During follow-up, 19 of the 29 patients died. Three patients received orthotopic liver transplantation. Four patients have been registered for transplantation, and the remaining three patients show signs of severe cholestasis. The actuarial estimate (Kaplan-Meier) indicated a survival free of liver transplantation of 55 % after 1 year, and only 14 % after 6 years. The median survival was 1.1 years. CONCLUSIONS: Progressive sclerosing cholangitis after septic shock is a recently described disease characterized by extremely short survival free of liver transplantation. This disease should be considered in patients who develop cholestasis following treatment of septic shock in an intensive care unit.

Expression of the multidrug resistance proteins MRP2 and MRP3 in human cholangiocellular carcinomas.

BACKGROUND: Cholangiocellular carcinomas and gallbladder carcinomas are highly aggressive tumours with a poor prognosis and are generally regarded as chemoresistant tumours. Overexpression of ATP-binding cassette transporters of the multidrug resistance protein (MDR) and multidrug resistance-related protein (MRP) family in cancer cells is a major cause for the multidrug resistance phenotype in vitro and in vivo. To further define the role of MRP family members in biliary tract cancer, we studied the expression and localization of MRP2 and MRP3 in cholangiocellular carcinomas and gallbladder carcinomas. MATERIALS AND METHODS: The expression and cellular localization of the multidrug resistance proteins MRP2 and MRP3 in human cholangiocellular carcinomas and gallbladder carcinomas were analysed by immunohistochemistry using isoform-specific antibodies. Expression of MRP isoforms was studied in vitro in Mz-ChA-1 cells derived from gallbladder adenocarcinoma by reverse transcription-polymerase chain reaction (RT-PCR), immunoblotting and immunofluorescence microscopy. RESULTS: Mz-ChA-1 cells constitutively expressed MDR P-glycoproteins, MRP1, MRP2 and MRP3 by RT-PCR, immunoblotting and immunofluorescence microscopy. MRP2 and MRP3 are expressed in the respective apical and basolateral membrane domains. MRP3 was the predominant MRP isoform in gallbladder carcinomas (93%) and cholangiocellular carcinomas (57%), whereas MRP2 expression was detected in only 29% of gallbladder carcinomas and was undetectable in cholangiocellular carcinomas. CONCLUSIONS: Our findings suggest that the intrinsic multidrug resistance of cholangiocellular and gallbladder carcinomas seems to be independent of MRP2 expression while the expression of MRP3 may contribute to the MDR phenotype.

HJV gene mutations in European patients with juvenile hemochromatosis.

A large variety of mutations within the genes encoding hepcidin (HAMP) and hemojuvelin (HJV) have been identified in patients with the severe iron overload disorder juvenile hemochromatosis (JH). The aim of the present study was to evaluate the molecular background of JH in patients from central parts of Europe. Sequence analyses of HAMP and HJV were performed in seven JH patients from six families from Germany, Slovakia, and Croatia. For detection of the G320V mutation in HJV, a rapid polymerase chain reaction-based assay was developed. No mutations were found within the HAMP gene. Six of seven (86%) JH patients carried at least one copy of the G320V mutation within the HJV gene. Four of these patients were homozygous for the G320V mutation. In addition, two novel HJV mutations were identified (C119F and S328fsX337). Taken together, the present study demonstrates that molecular analysis of the HJV gene is a powerful tool for an early and reliable diagnosis of JH. As in affected patients from Greece, the G320V mutation seems to be widely distributed among JH patients from central parts of Europe. Therefore, detection of the G320V mutation could identify the majority of JH cases from these regions non-invasively.

The iron-regulatory peptide hormone hepcidin: expression and cellular localization in the mammalian kidney.

It is generally accepted that iron homeostasis is mainly controlled in the gastrointestinal tract by absorption of dietary iron. However, recent studies have shown that the kidneys are also involved in iron metabolism. Since the iron-regulatory and antimicrobial peptide hormone hepcidin was originally isolated from human urine we have investigated the expression as well as the zonal and cellular localization of hepcidin in the mammalian kidney and developed an ELISA assay to analyze hepcidin concentrations in serum and urine. The expression of hepcidin was shown by RT-PCR and immunoblot experiments; its cellular localization was studied by immunocytochemistry in human, mouse and rat kidney, which revealed similar patterns of immunoreactivity. Hepcidin expression was absent from the proximal tubule and descending and ascending thin limbs. There was strong expression in the thick ascending limb of the cortex and in connecting tubules. Moderate expression was noted in the thick ascending limb and collecting ducts of the medulla and in collecting ducts of the papilla. Importantly, the cells of the macula densa were unstained. At the cellular level, hepcidin was localized to the apical cell pole of the renal epithelial cells. Based on its presence in urine, hepcidin may be released apically into the urine. Enhanced levels of hepcidin were determined in patients with chronic renal insuffciency (156.8 ng/ml, controls 104.2 ng/ml) indicating that the kidneys may metabolize and/or eliminate the circulating peptide. From the expression of hepcidin in the mammalian kidney, we have concluded that the iron-regulatory hormone is an intrinsic renal peptide which is not only eliminated by the kidney but is also synthesized in the kidney tubular system. Localization of hepcidin in the kidney implicates an iron-regulatory role of this peptide hormone in the renal tubular system, possibly in connection with the iron transporter divalent metal transporter-1.

Pro-hepcidin: expression and cell specific localisation in the liver and its regulation in hereditary haemochromatosis, chronic renal insufficiency, and renal anaemia.

BACKGROUND AND AIMS: The hepatic peptide hormone hepcidin, which has recently been isolated from human plasma and urine, is thought to be a central regulator of iron homeostasis. We investigated the presence and cellular localisation of hepcidin in the liver and developed a non-invasive assay to analyse its regulation in patients with hereditary haemochromatosis (HH), chronic renal insufficiency (CRI), and renal anaemia (RA). METHODS: Expression and localisation of hepcidin was shown by reverse transcription-polymerase chain reaction, western blot, immunocytochemistry, and immunofluorescence in human and guinea pig liver. Serum concentrations were determined in various groups of patients using a sensitive enzyme linked immunosorbent assay (ELISA). RESULTS: Western blot analysis with region specific antibodies identified a approximately 10 kDa peptide corresponding to the apparent molecular mass of pro-hepcidin. Localisation studies revealed that pro-hepcidin is expressed at the basolateral membrane domain of hepatocytes and is also present in blood. We developed a stable sensitive ELISA for detection and determination of pro-hepcidin in human serum. Mean pro-hepcidin level in human serum of healthy volunteers was 106.2 ng/ml. Enhanced levels of pro-hepcidin (148.1 ng/ml) were found in patients with CRI but normal haemoglobin values, indicating that the kidneys may metabolise and/or eliminate the circulating hormone. In contrast, concentrations of pro-hepcidin were significantly decreased in patients with HH (70.2 ng/ml) and also in patients with RA (115.0 ng/ml) compared with the CRI group. CONCLUSIONS: From the detection of pro-hepcidin in human serum, we conclude that the prohormone may be involved in the regulation of iron metabolism in HH. Decreased pro-hepcidin levels could play an important role in the pathogenesis of HH.

Identification of somatostatin receptor subtypes 1, 2A, 3, and 5 in neuroendocrine tumours with subtype specific antibodies.

BACKGROUND AND AIMS: Recently, novel somatostatin receptor (sstr) subtype specific ligand analogues have been developed for medical treatment of neuroendocrine tumours expressing different sstrs (sstr1-5). At present, individual expression patterns of sstr subtypes are based on methods such as in situ hybridisation and polymerase chain reaction at the transcriptional level. Therefore, we generated subtype specific antibodies against sstr1, 2A, 3, and 5 and analysed their presence, cellular localisation, distribution, and expression pattern in 33 gastrinomas, 36 insulinomas, and 35 tumours associated with a carcinoid syndrome by immunohistochemistry at the translational level. METHODS: Western blotting experiments were performed in the normal human pancreas used as a reference organ and in tumour tissues; at the cellular level, sstrs were localised by immunohistochemistry in tissue paraffin sections. RESULTS: In western blot analyses, the antibodies identified the respective receptors in their correct molecular range in extracts of the pancreas and neuroendocrine tumours. Using immunohistochemistry and immunofluorescence, the antibodies specifically detected the receptors in islet cells of the normal pancreas. Immunohistochemistry in the tumours revealed that all investigated sstr subtypes were highly expressed in the different tumour types. The frequency and expression pattern of the individual sstr subtypes varied considerably not only between the different tumour types but also in each patient. CONCLUSIONS: We conclude that immunohistochemistry with subtype specific antibodies can be used in clinical routine work to analyse sstr expression patterns for each patient before treatment and to facilitate well directed individual medical therapy by administering subtype specific somatostatin analogues.

Guanylin in the human pancreas: a novel luminocrine regulatory pathway of electrolyte secretion via cGMP and CFTR in the ductal system.

Cystic fibrosis transmembrane conductance regulator (CFTR) is a channel and regulator protein that is crucially involved in transepithelial ion transport. In the exocrine pancreas, the CFTR-mediated secretion of an electrolyte-rich fluid is a major but as yet incompletely understood function. We show here that the peptide guanylin is a specific activator of CFTR function in the human pancreas implicating regulation of pancreatic electrolyte secretion. Guanylin and its affiliated signaling and effector proteins including guanylate cyclase C, cGMP-dependent protein kinase II, CFTR, and the epithelial Cl-/HCO3- exchanger, anion exchanger 2, are highly expressed in the human pancreas. Guanylin is localized specifically to the typical centroacinar cells and proximal duct cells which, based on its additional presence in the pancreatic juice, is obviously released luminally into the pancreatic ducts. The guanylin receptor and the respective functional downstream proteins are all confined to the apical membrane of the duct cells implicating an as yet unknown route of luminal regulatory pathway of electrolyte secretion in the ductal system. Functional studies in two different human pancreatic duct cell lines expressing the CFTR Cl- channel that is functionally intact in CAPAN-1 cells but defective (delta F508) in CFPAC-1 cells clearly identify guanylin as a specific regulator of pancreatic CFTR channel function. Whole-cell patch-clamp recordings in CAPAN-1 cells revealed that forskolin induces an increase of Cl- conductance mediated by cAMP. In contrast, guanylin increased Cl- conductance in the same cells via cGMP but not cAMP; the respective membrane current was largely blockable by the sulfonylurea glibenclamide. In CFPAC-1 cells, however, neither guanylin nor forskolin produced a current activation. Based on the present findings we conclude that guanylin is an intrinsic pancreatic regulator of Cl- current activation in pancreatic duct cells via cGMP and CFTR. Remarkably, in the pancreas guanylin may exert its function through an intriguing luminocrine mode via the pancreatic juice.

Guanylin and uroguanylin in the parotid and submandibular glands: potential intrinsic regulators of electrolyte secretion in salivary glands.

The intestinal peptides guanylin and uroguanylin regulate the electrolyte/water transport in the gastrointestinal epithelium via activation of cystic fibrosis transmembrane conductance regulator (CFTR), the cystic fibrosis gene product. Because a major but incompletely understood function of the salivary glands is the CFTR-mediated secretion of an electrolyte-rich fluid, we investigated the rat and guinea pig parotid and submandibular glands for expression, cellular distribution, and subcellular localization of guanylin and uroguanylin. RT-PCR analyses with guanylin and uroguanylin-specific primers revealed that both peptides are highly expressed in the parotid and submandibular glands. At the translational level, western blotting analyses with peptide-specific guanylin and uroguanylin antibodies identified the expected 12.5-kDa immunoreactive peptides in these organs. At the cellular level, guanylin and uroguanylin were exclusively confined to epithelial cells of the intralobular and interlobular ducts. At the subcellular level, the immunoreactivities were localized by preembedding immunoelectron microscopy to small vesicles which were concentrated at the apical part of the secretory epithelial cells. The expression and cell-specific localization of guanylin and uroguanylin in the salivary glands indicate that these peptides may be specifically involved in the regulation of CFTR-mediated electrolyte/water secretion in the salivary gland ductal system.

Uroguanylin and guanylate cyclase C in the human pancreas: expression and mutuality of ligand/receptor localization as indicators of intercellular paracrine signaling pathways.

The intestinal peptide hormone uroguanylin regulates electrolyte/fluid transport in the gastrointestinal epithelium by binding to its receptor, guanylate cyclase C (GC-C), and thus specifically coupling to activation of cystic fibrosis transmembrane conductance regulator (CFTR). Since CFTR is crucially involved in pancreatic electrolyte secretion, we investigated the human pancreas for expression and cell-specific localization of uroguanylin and guanylate cyclase C as potential regulatory components of pancreatic electrolyte secretion. RT-PCR analyses with specific primers revealed that uroguanylin and GC-C are expressed in the human pancreas (and in the duodenum, used as positive control); at the translational level, western blotting analyses with peptide- and region-specific antibodies identified the presence of 12.5 kDa uroguanylin and 130 kDa GC-C in both human pancreatic and intestinal extracts. At the cellular level, uroguanylin and GC-C immunoreactivities were absent from the islets of Langerhans but were exclusively confined to the exocrine parenchyma. Hence, uroguanylin was localized to the centroacinar cells typical of the pancreas, and also to epithelial cells of the intercalated, intralobular and interlobular ducts where the peptide was primarily concentrated adluminally to the apical portion of the respective cells. Coincidently, correlative studies localized the GC-C receptor to the epithelial cells of the ductal network, where it was confined exclusively to the apical cell membrane that evidently represents the functionally relevant target membrane domain for the regulatory peptide. In view of the fact that CFTR is highly expressed in pancreatic ductal cells where uroguanylin and its receptor are also localized, we assume that uroguanylin, an intrinsic pancreatic peptide, is involved in the regulation of electrolyte/water secretion in the ductal system via GC-C and CFTR. The particular cellular expression of uroguanylin in duct cells and the localization of GC-C to the duct cell apical membrane domain predict a novel route of intercellular signaling and luminal activation of GC-C via the pancreatic juice.

Expression and cell-specific and membrane-specific localization of NHE-3 in the human and guinea pig upper gastrointestinal tract.

Na+/H+ exchangers (NHEs) are vital transmembrane transport proteins mediating the electroneutral exchange of Na+ and H+ ions in mammalian cells. In the epithelium of the lower intestine, the isoform NHE-3 is apparently involved in Na+ absorption; however, its presence and cellular localization in the duodenum and particularly in the stomach remain largely unclear. Therefore, we studied the human and guinea pig stomach and duodenum for the expression, regional and mucosal distribution pattern, and membrane-specific localization of NHE-3. Reverse transcription/polymerase chain reaction analyses revealed strong expression of NHE-3 in the stomach and duodenum, where it was identified as a 85-kDa immunoreactive protein by Western blotting experiments. Whereas NHE-3 was localized to the basolateral membrane of surface mucous cells of the stomach, it was exclusively confined to the brush border membrane of epithelial cells in the duodenum. We conclude that the basolateral NHE-3 in the stomach protects the mucosa by secreting protons that diffuse into the mucous cells. In the duodenum, the localization of NHE-3 to the apical membrane of enterocytes suggests a resorptive function by directional Na+ transport. These findings indicate that NHE-3 may be involved in various segment-specific functions in the upper gastrointestinal tract.

Expression and cell-specific localization of the cholecystokinin B/gastrin receptor in the human stomach.

Gastrin stimulates gastric acid secretion by acting on the cholecystokinin B/gastrin receptor (CCK-BR). The localization of this receptor at the cellular level showed conflicting results in animal studies and has not been described in man by immunohistochemistry. The aim of the present study is to characterize the precise cellular location of the CCK-BR in the human stomach. Polyclonal antisera were raised against different epitopes of the CCK-BR molecule and used for immunohistochemical investigations. CCK-BR mRNA was detected in paraffin tissue sections by the highly sensitive method of in situ reverse transcriptase-polymerase chain reaction (RT-PCR). Using immunohistochemistry, CCK-BR could successfully be localized in gastric parietal cells. In the majority of parietal cells, CCK-BR immunoreactivity was present a he basolateral cell membrane domain. In some parietal cells, a granular pattern of immunoreactivity was exclusively confined to the cytoplasm of the cells. CCK-BR mRNA was found in parietal cells and in enterochromaffin-like (ECL) cells by means of in situ RT-PCR. No expression of CCK-BR was found in the gastric antral mucosa. Our data support the concept that gastrin stimulates gastric acid secretion directly via CCK-B receptors on parietal cells and indirectly by inducing histamine release from histamine-containing ECL cells, which contributes to acid secretion by parietal cells.

Expression of guanylin in "pars tuberalis-specific cells" and gonadotrophs of rat adenohypophysis.

The intestinal peptide guanylin regulates the electrolyte/water transport in the gastrointestinal epithelium by paracrine/luminocrine mechanisms. Because guanylin also circulates in the blood, we investigated the rat hypothalamo-pituitary region for expression and cellular localization of this peptide. Reverse transcriptase-PCR analyses with guanylin-specific primers revealed expression of the peptide in the pars tuberalis and pars distalis of the pituitary. Western blotting analyses in hypophyseal tissue extracts identified the expected 12.5-kDa immunoreactive peptide by using two different region-specific guanylin antisera. Light and electron microscopic immunocytochemistry with the same antisera localized guanylin in "pars tuberalis-specific cells" in the juxtaneural pars tuberalis adjacent to nerve endings and blood vessels of the hypothalamo-pituitary portal system and in gonadotrophic cells within the distal pars tuberalis and ventrolateral part of the pars distalis. The presence and cell-specific localization of guanylin within the hypothalamo-hypophyseal system indicate that this peptide may be specifically involved in paracrine and endocrine regulatory mechanisms.