The Voronoi theory of the normal liver lobular architecture and its applicability in hepatic zonation.

The precise characterization of the lobular architecture of the liver has been subject of investigation since the earliest historical publications, but an accurate model to describe the hepatic lobular microanatomy is yet to be proposed. Our aim was to evaluate whether Voronoi diagrams can be used to describe the classic liver lobular architecture. We examined the histology of normal porcine and human livers and analyzed the geometric relationships of various microanatomic structures utilizing digital tools. The Voronoi diagram model described the organization of the hepatic classic lobules with overall accuracy nearly 90% based on known histologic landmarks. We have also designed a Voronoi-based algorithm of hepatic zonation, which also showed an overall zonal accuracy of nearly 90%. Therefore, we have presented evidence that Voronoi diagrams represent the basis of the two-dimensional organization of the normal liver and that this concept may have wide applicability in liver pathology and research.

The prognostic value of histology in the assessment of patients with Budd-Chiari syndrome.

BACKGROUND/AIMS: It is unclear whether treatment of patients with Budd-Chiari syndrome (BCS) should be based on liver histology, as large histopathological studies have not been performed. We investigated the relationship between the histopathological findings and survival. METHODS: We studied the clinical features and findings on biopsy specimens in 45 patients with BCS who were admitted to four tertiary referral medical centers. Histological findings, i.e. congestion, necrosis, inflammation and fibrosis, were graded. Survival was assessed in relation to histological findings and clinical features at the time of diagnosis as well as in relation to subsequent treatment with or without portosystemic shunting. RESULTS: Centrilobular congestion, centrilobular necrosis, lobular inflammation and portal inflammation were not significantly related to survival. In addition, there was no association between either pericentral or periportal fibrosis and survival. Univariate analysis revealed that the prothrombin time and Child-Pugh score were significantly related to survival (P = 0.005 and Ptrend = 0.02, respectively). Multivariate analysis yielded the Child-Pugh score, serum alanine aminotransferase (ALT) and treatment with portosystemic shunting as independent prognostic indicators. CONCLUSIONS: We found no evidence for a relationship between early liver pathology and survival. Child-Pugh score, serum ALT and portosystemic shunting appeared to be prognostic indicators for patients with BCS.

Endoscopic circumferential esophageal mucosectomy in a porcine model: an assessment of technical feasibility, safety, and outcome.

BACKGROUND AND STUDY AIMS: Endoscopic mucosectomy has been performed for early cancers and dysplastic lesions < or = 2 cm in diameter. The feasibility and safety of mucosectomy for circumferential lesions of the esophagus is uncertain. The aim of this study was to determine the technical feasibility, as well as the short and long-term complication rates, with circumferential endoscopic mucosectomy of the distal esophagus in the pig. MATERIALS AND METHODS: Circumferential endoscopic mucosectomy of the distal 3 cm of the esophagus was performed in four pigs, using a cap mucosectomy device. The animals were sacrificed after 30, 50, 70, and 90 days to assess mucosal regeneration and stricture formation. RESULTS: The procedure time for circumferential endoscopic mucosectomy was 15-30 min. Circumferential endoscopic mucosectomy was technically feasible and without short-term complications. Videotapes of all resections were reviewed to ensure that complete removal of the mucosa was achieved. All mucosectomy specimens underwent histological evaluation. The specimens included the mucosa alone in three of the pigs. Some of the specimens in the fourth pig included a superficial layer of muscularis propria. This pig failed to thrive. Macroscopic examination of the dissected esophageal specimens from the healthy pigs revealed a well-healed, normal-appearing esophagus, whereas a stenosis of 4 x 10 mm was observed in the distal esophagus of the pig that failed to thrive. CONCLUSIONS: Circumferential endoscopic mucosectomy of the porcine distal esophagus is feasible and safe. An adequate submucosal saline cushion is essential to prevent stenosis due to deep injury.

Frequency of nonalcoholic steatohepatitis as a cause of advanced liver disease.

Although nonalcoholic steatohepatitis (NASH) has generally been considered a benign condition, the increasing prevalence and severity of obesity has heightened concerns about the frequency with which NASH progresses to end-stage liver disease. The aim of this study is to determine the frequency, clinical features, and posttransplantation history of decompensated liver disease secondary to NASH. The frequency of NASH as a cause of end-stage liver disease was prospectively determined in patients evaluated for liver transplantation. NASH was considered to be the primary cause of liver disease in patients who had histological evidence of steatohepatitis and in whom chronic liver diseases other than NASH were excluded. Posttransplantation histological characteristics were also determined in patients with NASH and compared with those of patients with pretransplantation diagnoses of cholestatic liver diseases, alcoholic disease, and hepatitis C. Of 1,207 patients evaluated for liver transplantation during the study period, 31 patients (2.6%) had NASH as the primary cause of liver disease. In the same period, 546 liver transplantations were performed, 16 of which (2.9%) were for end-stage disease secondary to NASH. Posttransplantation steatosis was seen in 60% of transplant recipients with NASH versus 5% of those with cholestatic disease, 15% of those with alcoholic disease, and 15% of those with hepatitis C. Steatohepatitis recurred in 33% of transplant recipients with NASH, with progression to cirrhosis in 12.5%. NASH can progress to end-stage liver disease in a minority of affected patients and was the primary cause of liver disease in 2.9% of patients evaluated for liver transplantation at our center. Recurrence of steatosis and NASH is frequent and can be severe after liver transplantation.

Primary extrapulmonary sugar tumor (PEST): a report of four cases.

The cell of origin and direction of differentiation of the clear cell tumor of the lung (the so-called sugar tumor) remains enigmatic. Recognition of HMB-45 immunoreactivity and identification of melanosomes have suggested a relationship to angiomyolipoma of kidney or liver and lymphangiomyoma. This has given rise to the concept that clear cell tumors are neoplasms of so-called perivascular epithelioid cells--PEComas. Herein we report the existence of four similar tumors occurring in extrapulmonary sites, one of which had malignant features. The three benign tumors occurred in females ages 9, 20, and 40 years; two were located in the rectum and one in the vulva. The malignant tumor occurred in the inter-atrial cardiac septum of a 29-year-old man. Common histologic features were a richly vascular organoid architecture, tumor cells with clear to pale eosinophilic cytoplasm, abundant glycogen, and immunoreactivity for HMB 45, but not S100, multiple keratin, neuroendocrine, or muscle markers. Benign tumors demonstrated low mitotic activity, no necrosis, and good circumscription; the malignant tumor showed considerable mitotic activity, necrosis, and an infiltrative growth pattern. Ultrastructurally, glycogen was present, mitochondria were abundant, and membrane-bound lamellated bodies consistent with premelanosomes were present in two cases, and equivocal in one. Because these tumors have light microscopic, immunohistochemical, and electron microscopic features similar to pulmonary sugar tumors, we propose the name primary extrapulmonary sugar tumor (PEST) for them. Although most PEST's are probably benign, malignant forms appear to exist. These cases further support the concept of a family of systemic HMB-45 positive tumors that include sugar tumors, angiomyolipoma of kidney or liver, lymphangiomyomas, and clear-cell myomelanocytic tumors of the falciform ligament/ligamentum teres.

Adenosquamous and squamous carcinoma of the colon and upper rectum: a clinical and histopathologic study.

PURPOSE: Squamous and adenosquamous carcinoma of the colon and proximal rectum are rare neoplasms in which the clinicopathologic behavior and the most appropriate management are unknown. The purpose of this study was to review the histology and clinical course of the largest series of cases ever reported from a single center on this rare condition. METHOD: The Mayo Clinic tissue registry was searched for all primary cases of squamous and adenosquamous carcinoma of the colon or rectum proximal to 8 cm from the dentate and presenting before December 31, 1992. Of the 52 identified cases there was adequate histologic material for review in 44 cases. These cases were divided into pure squamous-cell carcinoma (n = 11), mixed adenosquamous carcinoma (n = 31), and adenocarcinoma with benign-appearing squamous metaplasia (adenoacanthoma; n = 2). Squamous-cell carcinomas were examined for evidence of human papilloma virus by in situ hybridization. A retrospective review of medical records was undertaken in all 52 cases with respect to predisposing factors, clinicopathologic behavior, prognostic features, and treatment with adjuvant therapy. RESULTS: The charts of 52 patients (20 females), with a mean age of 58.6 (range, 19-90) years, were reviewed. Right-sided lesions were the most common (43 percent). Metastatic disease was evident at presentation in 49 percent of patients, the most common sites in order being liver, peritoneal, and lung. The five-year overall survival rate was 34 percent, Stage I to III disease had a 65 percent five-year survival rate, and Stage IV mean survival time was 8.5 months. For node-positive and node-negative disease, 23 and 85 percent, respectively, survived five years. There was no evidence of human papilloma virus in the six squamous-cell carcinomas examined. CONCLUSION: Squamous and adenosquamous carcinomas of the colon and rectum are rare neoplasms. Although a poor prognosis can be expected for node-positive disease, patients with negative nodes do generally the same as patients with adenocarcinoma histology. Based on advances made with multimodality therapy of squamous-cell cancer of the anus and adenocarcinoma of the rectum, further studies should define the role of postoperative therapies for these lesions.

Epidemiology and natural history of primary biliary cirrhosis in a US community.

BACKGROUND & AIMS: The epidemiology of primary biliary cirrhosis (PBC) has not been studied systematically in the United States. We report the incidence and prevalence of this condition in the general population. We also examined the validity of the Mayo natural history model for PBC among these unselected patients from the community. METHODS: The Rochester Epidemiology Project entails a computerized index of diagnoses from the health care encounters of residents of Olmsted County, Minnesota. For potential cases identified using this database, the complete (inpatient and outpatient) medical records were reviewed to verify the diagnosis and extract information necessary for the application of the Mayo model. We estimated the incidence and prevalence of PBC in this population and compared the actual survival of patients with PBC in the community with the survival predicted for PBC patients by the Mayo natural history model. RESULTS: The age-adjusted (to 1990 U.S. whites) incidence of PBC per 100,000 person-years for years 1975-1995 was 4.5 (95% confidence interval [CI], 3.1-5.9) for women, 0.7 (95% CI, 0.1-1.3) for men, and 2.7 (95% CI, 1.9-3.5) overall. The age- and sex-adjusted prevalence per 100,000 persons as of 1995 was 65.4 (95% CI, 43.0-87.9) for women, 12.1 (95% CI, 1.1-23.1) for men, and 40.2 (95% CI, 27.2-53.1) overall. The Mayo natural history model accurately predicted the actual survival of these patients. CONCLUSIONS: This first description of the epidemiology of PBC in the United States indicates that its incidence and prevalence in this country are among the highest reported. Outcomes among these unselected patients from a community population further validated the Mayo natural history model of PBC.

Oral budesonide in the treatment of primary sclerosing cholangitis.

OBJECTIVE: This study was designed to evaluate the safety and estimate the efficacy of oral budesonide in patients with primary sclerosing cholangitis (PSC). METHODS: Twenty-one patients with PSC were treated with 9 mg daily of oral budesonide for 1 yr. RESULTS: Significant, but marginally important, improvement in serum alkaline phosphatase (1,235 +/- 190 vs 951 +/-206 U/L, p = 0.003) and AST levels (119 +/- 14 vs 103 +/- 19 U/L, p = 0.02) was noted at the end of the treatment period. Serum bilirubin levels increased significantly in the 18 patients who completed 1 yr of treatment (1.1 +/- 0.1 vs 1.4 +/- 0.3, p = 0.01) and no significant changes in liver tests were noted 3 months after budesonide was discontinued. The Mayo risk score did not change significantly, and although a significant improvement in the degree of portal inflammation was noted at the end of the treatment period, the degree of fibrosis and stage of disease were not significantly affected. There was a marked loss of bone mass of the femoral neck (0.851 +/- 0.02 vs 0.826 +/- 0.02 g/cm2, p = 0.002) and lumbar spine (1.042 +/- 0.02 vs 1.029 +/- 0.02 g/cm2, p = 0.09) at 1 yr of treatment with budesonide. Two patients required evaluation for liver transplantation during treatment, and two patients developed cosmetic side effects. CONCLUSIONS: Oral budesonide appears to be of minimal, if any, benefit and it is associated with a significant worsening of osteoporosis in patients with PSC.

Comparative allograft histology after liver transplantation for cryptogenic cirrhosis, alcohol, hepatitis C, and cholestatic liver diseases.

BACKGROUND: End-stage liver disease for which no cause can be identified, cryptogenic cirrhosis, is a common indication for liver transplantation. Allograft inflammation and fibrosis have been reported to recur with similar frequencies after liver transplantation for cryptogenic cirrhosis and hepatitis C (HCV). METHODS: We determined sequential posttransplant allograft histology in four groups of recipients: 31 transplanted for cryptogenic cirrhosis, 70 for cholestatic etiologies, 40 for alcoholic liver disease, and 56 for HCV. Modified hepatitis activity index (HAI) and fibrosis stage were determined at 4 months, 1 year, and at most recent biopsy posttransplantation. RESULTS: The prevalence of HAI > or = 2 among cryptogenic recipients was similar to that of cholestatic and alcoholic recipients at 4 months, 1 year, and at most recent evaluation (mean 45+/-17 months posttransplantation). For HCV-infected recipients, the frequency of HAI > or = 2 was more than for cryptogenic recipients at 1 year (52 vs. 29%, P=0.04) and at most recent evaluation (64 vs. 15%, P=0.003). Fibrosis scores for cryptogenic, cholestatic, and alcoholic recipients were similar at all timepoints. The proportion of HCV-infected recipients with fibrosis stage >2 was more than that of cryptogenic recipients at 4 months (29 vs. 12%, P=0.05), 1 years (46 vs. 7%, P=0.0002), and at most recent evaluation (42 vs. 15%, P=0.06). None of the cryptogenic recipients developed cirrhosis. RESULTS: The frequency of elevated HAI and fibrosis stage in recipients who undergo transplantation for cryptogenic cirrhosis is similar to that of recipients who undergo transplantation for cholestatic etiologies and significantly less than that of HCV-infected recipients. Fibrosis stage and HAI are generally stable after transplantation for cryptogenic cirrhosis. These data do not suggest a viral etiology of liver disease in the majority of patients with cryptogenic cirrhosis.

Early detection of hepatitis C allograft reinfection after orthotopic liver transplantation: a molecular and histologic study.

After orthotopic liver transplantation (OLT), patients with chronic hepatitis C virus (HCV) infection show nearly universal persistence of viremia and reinfection of the liver, but identifying the point at which the liver is reinfected morphologically can be difficult. One tool that may potentially be useful to detect reinfection is reverse transcriptase-polymerase chain reaction (RT-PCR), which has proven to be highly sensitive for detecting HCV RNA in formalin-fixed paraffin-embedded liver tissue. Our purpose was to gain insight into the time frame of HCV reinfection by assaying for HCV RNA in serial posttransplant liver biopsy specimens. Our study population consisted of 14 patients who underwent liver transplantation for hepatitis C and had confirmed HCV RNA in pretransplant serum, absence of HCV RNA in donor livers, and available consecutive posttransplant liver allograft specimens. We performed RT-PCR for HCV RNA in serial posttransplant liver biopsy specimens, beginning at 1 week until at least one biopsy from each tested positive. HCV RNA was detected in liver tissue by RT-PCR in 1-week post-OLT liver samples in 6 of 14 (42.8%) patients, the earliest being 5 days post-OLT. Eventually, each of the remaining eight samples became RT-PCR positive as well; the first detections occurred in these at 3 weeks (three cases), 4 weeks (three cases), 48 weeks (one case), and 144 weeks (one case). Histologic identification of hepatitis C recurrence was relatively insensitive in relation to these molecular data. These data suggest that (1) HCV RNA reinfection is nearly universal after liver transplantation in patients with chronic hepatitis C infection, (2) molecular reinfection by HCV occurs at a variable interval post-OLT, with the majority of allograft livers reinfected as early as 1 week, and (3) morphologic features of hepatitis C are usually appreciable at the time of "molecular" recurrence.

Amyloidosis of the alimentary canal: radiologic-pathologic correlation of CT findings.

BACKGROUND: The purpose of the study was to describe the computed tomographic (CT) findings of the alimentary canal and mesentery in amyloid infiltration of the gastrointestinal (GI) tract and to correlate the CT findings with histologic extent and distribution and with amyloid subtype. METHODS: Abdominal CT scans performed between 1988 and 1997 on patients with pathologically proven amyloidosis of the alimentary canal and mesentery. Histology was graded for extent of mucosal, submucosal, and muscularis propria involvement and for degree of interstitial and vascular distribution. CT findings were correlated with histologic extent, histologic distribution, and amyloid histochemical type. RESULTS: Twenty-three patients were included. Four (17%) had bowel wall thickening, which was associated with a higher submucosal extent and interstitial distribution than in patients with normal bowel by CT. Four (17%) patients had bowel wall dilatation without thickening, which was not associated with statistically significantly different histology than in patients with normal bowel by CT. There was no statistically significant correlation between CT findings and histochemical subtype. Mesenteric soft tissue infiltration was seen in two patients, and mesenteric adenopathy was seen in one patient. CONCLUSIONS: Normal bowel is a common abdominal CT finding in amyloidosis of the alimentary canal. When findings are present, GI wall thickening and/or bowel wall dilatation without wall thickening may be seen. Bowel wall thickening on CT correlates with submucosal extent and interstitial distribution of disease. Soft tissue infiltration and adenopathy are also occasionally seen.

Time course of histological progression in primary sclerosing cholangitis.

OBJECTIVE: The aim of this study was to determine the time course over which patients with primary sclerosing cholangitis (PSC) progress through the histological stages of the disease. METHODS: One hundred seven patients with PSC who had at least two liver biopsies were identified. The stage information from two consecutive biopsies formed one observation and a continuous time Markov model was used to describe the rate of progression between biopsies. RESULTS: Three hundred seven liver biopsies were performed in the 107 patients giving a total of 200 observations. At 1 yr, 42% of patients in stage II disease progress, 66% at 2 yr, and 93% at 5 yr; whereas 14% of patients in stage III progress at 1 yr, 25% at 2 yr, and 52% at 5 yr. The frequency of progression of stage I disease could not be determined because of the small number of patients in stage I. Regression of histological stage was observed in 30 of 200 total observations (15%), and in 30 of 85 observations (35%) in which there was a change in stage. CONCLUSIONS: These data regarding histological progression in PSC may be potentially helpful in determining the number of patients and length of time necessary to appreciate a treatment effect in clinical trials. However, the high degree of sampling variability in PSC may restrict the usefulness of serial liver biopsies as a means of evaluating treatment efficacy.

Independent predictors of liver fibrosis in patients with nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) may present with increased hepatic fibrosis progressing to end-stage liver disease. No factors that determine increasing fibrosis and histologically advanced disease have been recognized, thus, liver biopsy is recommended in all patients for diagnosis and prognosis. Our aim was to identify independent predictors of severe hepatic fibrosis in patients with NASH. One hundred and forty-four patients were studied. All patients underwent liver biopsy. Clinical and biochemical variables were examined with univariate and multivariate analysis. Thirty-seven (26%) patients had no abnormal fibrosis, 53 (37%) had mild fibrosis, 15 (10%) had moderate fibrosis, 14 (10%) had bridging fibrosis, and 25 (17%) had cirrhosis. In multivariate analysis, older age (P =. 001), obesity (P =.002), diabetes mellitus (P =.009), and aspartate transaminase/alanine transaminase (AST/ALT) ratio greater than 1 (P =.03) were significant predictors of severe liver fibrosis (bridging/cirrhosis). Body mass index (P =.003) was the only independent predictor of the degree of fat infiltration. Increased transferrin saturation correlated positively with the severity of fibrosis (P =.02) in univariate analysis, and there was a trend for more female patients among those with more advanced fibrosis (P =. 09). However, iron studies or gender were not significant when controlled for age, obesity, diabetes, and AST/ALT ratio. In conclusion, older age, obesity, and presence of diabetes mellitus help identify those NASH patients who might have severe liver fibrosis. This is the subgroup of patients with NASH who would be expected to derive the most benefit from having a liver biopsy and considering investigational therapies.

Update on hereditary hemochromatosis and the HFE gene.

Hereditary hemochromatosis (HHC) is the most common inherited single gene disorder in people of northern European descent. Hereditary hemochromatosis is characterized by increased intestinal absorption of iron leading to its deposition into multiple organs. The classic description of HHC is bronze diabetes in a patient with cirrhosis. Hereditary hemochromatosis is increasingly being diagnosed at an earlier, less symptomatic stage. Diagnosis is based on an elevated fasting early morning transferrin saturation. Treatment is by phlebotomy, which, if initiated before the development of cirrhosis or diabetes, is associated with a normal life expectancy. Recently, a gene associated with HHC was discovered and named HFE. Two point mutations of this gene have been referred to as C282Y and H63D. Several US and European studies have found that 60% to 93% of patients with suspected HHC are homozygous for C282Y. Positive results of HFE gene testing may eliminate the need for a liver biopsy in selected cases. The greatest utility of HFE gene testing will likely be in screening family members of an identified proband and in helping to resolve ambiguous cases.

Evolving concepts in the diagnosis, pathogenesis, and treatment of chronic hepatic allograft rejection.

Chronic hepatic allograft rejection is characterized by the histological findings of ductopenia and a decreased number of hepatic arteries in portal tracts in the presence of foam cell (obliterative) arteriopathy. Recent studies have extended the histological spectrum of chronic rejection to include the presence of biliary epithelial atrophy or pyknosis involving the majority of small ducts present in the liver biopsy specimen. Overall, the incidence of chronic rejection in adults appears to be decreasing and is currently approximately 4%. However, the incidence of chronic rejection in pediatric liver transplant recipients has been more stable and ranges from 8% to 12% in most studies. Clinical risk factors associated with chronic rejection include: underlying liver disease, HLA donor-recipient matching, positive lymphocytotoxic cross-match, cytomegalovirus infection, recipient age, donor-recipient ethnic origin, male donor into female recipient, number of acute rejection episodes, histological severity of acute rejection episodes, low cyclosporine trough levels, and retransplantation for chronic rejection. Chronic rejection, once diagnosed, frequently leads to graft failure; however, a number of reports indicated 20% to 30% of the patients with this diagnosis may respond to additional immunosuppressive therapy or even resolve spontaneously receiving baseline immunosuppression. Newer immunosuppressive agents, such as tacrolimus and mycophenolate, may successfully reverse chronic rejection, particularly when it is diagnosed in its early histological stages.

Acute and chronic hepatic allograft rejection: pathology and classification.

Hepatic allograft rejection has been divided into humoral (or hyperacute), acute (or cellular), and chronic (or ductopenic) forms. Humoral rejection is extremely uncommon in the liver and is not graded. Acute rejection will occur in approximately 50% of liver allografts, is more common in the first few weeks posttransplantation, and is defined by Snover's triad of portal hepatitis, endothelialitis (or endotheliitis), and lymphocytic cholangitis. This form of rejection is generally reversible, either spontaneously or with additional immunosuppressive therapy, and can be reliably graded using a system with categories of mild, moderate, and severe rejection, associated with 37%, 48%, and 75% unfavorable shortterm and 1%, 12%, and 14% unfavorable long-term outcomes, respectively. Chronic rejection is characterized histologically by progressive duct loss and a lipid-rich vasculopathy that can be difficult to diagnose in early phases. Chronic rejection typically occurs several months to a year posttransplantation, although exceptions exist.

Ursodeoxycholic acid inhibits eosinophil degranulation in patients with primary biliary cirrhosis.

Eosinophilia is a distinctive feature of primary biliary cirrhosis (PBC), especially in its early stages. Intriguingly, treatment with ursodeoxycholic acid (UDCA) ameliorates eosinophilia as well as liver tests in patients with PBC. It remains unknown, however, whether eosinophils in PBC patients are functionally activated and whether UDCA inhibits eosinophil activation. In the present study, we systematically examined eosinophil dynamics in the blood and liver in patients with stage I to II PBC before and after UDCA treatment. We determined serum concentrations of eosinophil granule proteins (major basic protein [MBP] and eosinophil-derived neurotoxin [EDN]) by radioimmunoassay and quantitated eosinophil degranulation using computer-assisted morphometry after MBP immunohistochemistry. Before UDCA treatment, patients with PBC (n = 25) showed significantly higher circulating eosinophil counts (P <. 05) and serum concentrations of MBP (P <.0005) and EDN (P <.02) compared with patients with chronic viral hepatitis (n = 22), autoimmune hepatitis (n = 10), and obstructive jaundice (n = 12). Four-week UDCA treatment significantly reduced blood eosinophil counts (P <.0001) and serum MBP (P <.0001) and EDN (P <.0001) levels in PBC patients. MBP immunohistochemistry and computer-assisted quantitative morphometry showed infiltration and degranulation of eosinophils in the portal tract in patients with PBC and significant reductions in the number of sites and the area occupied by extracellular MBP deposits after UDCA treatment for 2 years (P <.02) but not in placebo-treated patients. Our results suggest that eosinophils in patients with PBC are not only increased in number, but also release granule proteins, and that UDCA treatment inhibits this eosinophil activation/degranulation.

Spiral nitinol biliary stents in a porcine model: evaluation of the potential for use in benign strictures.

BACKGROUND AND STUDY AIMS: Self-expanding spiral nitinol stents are potentially removable and may be useful in the treatment of benign strictures. We evaluated the histologic response to stent placement and technical aspects of their placement and removal in a porcine model. METHODS: Nine animals were studied. Stents were placed above the papilla in six surviving animals. After intervals of one, two or three months cholangiography and attempted stent removal was performed. Four animals were then sacrificed acutely with their stent in place, and two were sacrificed after a one-month healing interval. The results of placement, follow-up cholangiography and histology are reported. RESULTS: Cholangiography and stent placement succeeded in 26 of 27 and 11 of 16 attempts, respectively. Three placement failures were attributed to stent/duct size disparity or a faulty release mechanism, resulting in stent kinking and/or duct twisting. Among the successfully deployed stents, two animals developed strictures where stents traversed bifurcations and one exhibited partial luminal compromise by tissue entrapment between coils. Fluoroscopically guided removal was successful in two of five stents positioned above the papilla. Histology was non-specific but minimally changed in those given a one-month healing interval after removal. Others exhibited moderate inflammation, fibrosis and an intramural abscess at sites of induced stricture. CONCLUSIONS: Spiral metal stents for the treatment of benign strictures remain experimental. Care must be taken to deploy them in bile ducts of adequate diameter and endoscopic removal is not yet demonstrably reliable and safe.