Sinusoidal Fibrosis Research Articles

Bevacizumab protects against sinusoidal obstruction syndrome and does not increase response rate in neoadjuvant XELOX/FOLFOX therapy of colorectal cancer liver metastases

Aim In patients suffering from colorectal cancer liver metastases, 5-fluorouracil-based chemotherapy plus oxaliplatin ensures superior response rates at the cost of hepatic injury. Knowledge about the consequences of bevacizumab on chemotherapy-induced hepatic injury and tumor response is limited. Methods Resected liver specimens from patients of two prospective, non-randomized trials (5-fluorouracil/oxaliplatin ± bevacizumab) were analyzed retrospectively. Hepatotoxicity to the non-tumor bearing liver was evaluated for sinusoidal obstruction syndrome, hepatic steatosis and fibrosis. Tumor response under chemotherapy was assessed according to Response Evaluation Criteria in Solid Tumors (RECIST). Results Bevacizumab decreased the severity of the sinusoidal obstruction syndrome. Bevacizumab had no impact on hepatic steatosis and fibrosis. The addition of bevacizumab to chemotherapy had no effect on tumor response compared to combination chemotherapy alone. Conclusions This analysis shows that bevacizumab protects against the sinusoidal obstruction syndrome and thus provides the histological explanation of the safe use of bevacizumab prior to liver resection. Furthermore, we show that bevacizumab does not improve tumor response according to RECIST.

Early Stellate Cell Activation and Veno-occlusive-disease (VOD)–like Hepatotoxicity in Dogs Treated with AR-H047108, an Imidazopyridine Proton Pump Inhibitor

Dogs treated with AR-H047108, an imidazopyridine potassium competitive acid blocker (P-CAB), developed clinical signs of hepatic dysfunction as well as morphologically manifest hepatotoxicity in repeat-dose toxicity studies. An investigative one-month study was performed, with interim euthanasia after one and two weeks. A detailed histopathological and immunohistochemical characterization of the liver lesions was conducted, including markers for fibrosis, Kupffer cell activation, apoptosis, and endothelial injury. In addition, hepatic retinoid and procollagen 1alpha2 mRNA levels in livers of dogs treated with AR-H047108 were analyzed. The results showed an early inflammatory process in central veins and centrilobular areas, present after one week of treatment. This inflammatory reaction was paralleled by activation of stellate/Ito cells to myofibroblasts and was associated with sinusoidal and centrivenular fibrosis. The early activation of stellate cells coincided with a significant decrease in retinyl ester levels, and a significant increase in procollagen 1alpha2 mRNA levels, in the liver. At later time points (three and six months), there was marked sinusoidal fibrosis in centrilobular areas, as well as occlusion of central veins resulting from a combination of fibrosis and increased thickness of smooth muscle bundles in the vessel wall. The pattern of lesions suggests a veno-occlusive-disease (VOD)-like scenario, possibly linked to the imidazopyridine chemical structure of the compound facilitated by specific morphological features of the dog liver.

Acute Liver Cell Damage in Patients With Anorexia Nervosa: A Possible Role of Starvation-Induced Hepatocyte Autophagy

Acute liver insufficiency is a rare complication of anorexia nervosa. The mechanisms for this complication are unclear. The aim of this study was to describe patient characteristics and clarify the mechanisms involved. Liver specimens from 12 patients (median age, 24 years; median body mass index, 11.3 kg/m(2)), with a prothrombin index <50% and/or an International Normalized Ratio >1.7 and anorexia nervosa as the only cause for acute liver injury were analyzed. A detailed pathologic examination was performed, including under electron microscopy. Liver cell glycogen depletion was a constant finding. There was a contrast between the increase in serum alanine aminotransferase (56 times normal on average; 1,904 IU/L) and the absence of significant hepatocyte necrosis on histology. Centrilobular changes (trabecular atrophy and/or sinusoidal fibrosis) were observed in 6 patients. There were rare or no (<5%) terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive hepatocytes, suggesting that apoptosis was not the primary mechanism. Hepatocytes from 4 patients showed numerous autophagosomes, a morphologic hallmark of autophagy, on electron microscopy. In contrast, the mitochondria, endoplasmic reticulum, and nuclei were normal in most cells. These features were absent in 11 control patients. The outcome was favorable in all patients, with a rapid return to normal liver function. Anorexia nervosa with extremely poor nutritional status should be added to the list of conditions causing acute liver insufficiency. Our findings show that starvation-induced autophagy in the human liver may be involved in liver cell death during anorexia nervosa, even though other mechanisms of liver cell damage could also play a role.

High Prevalence of Small Intestinal Bacterial Overgrowth in Patients with Morbid Obesity: A Contributor to Severe Hepatic Steatosis

With the increasing prevalence of obesity, non-alcoholic fatty liver disease (NAFLD) has become a major cause of liver diseases. Small intestinal bacterial overgrowth (SIBO) could be related to NAFLD. Our aim was to determine the prevalence of SIBO and its relationship with liver lesions in morbidly obese patients. A glucose hydrogen (H(2)) breath test (positive if fasting breath H(2) concentration > 20 ppm and/or an increase of > 10 ppm over baseline within the first 2 h) was performed in obese patients referred for bariatric surgery (body mass index [BMI] > 40 kg/m(2) or > 35 in association with comorbidities) and in healthy non-obese subjects. In obese patients, a surgical liver biopsy was performed. One hundred and forty-six patients (129 women, age [mean+/-SE]: 40.7 +/- 11.4 years) were prospectively included in the study. The mean BMI was 46.1+/-6.4 kg/m(2). A liver biopsy was available in 137 patients and a breath test in 136. The frequency of positive breath tests was higher in obese patients (24/136, 17.1%) than in healthy subjects (1/40, 2.5%; P=0.031). In the univariate analysis, SIBO was not associated with clinical variables, but tended to be associated with more frequent severe hepatic steatosis (26.3 vs. 10.3%, P=0.127), whereas the frequency of sinusoidal or portal fibrosis, lobular necrosis and non-alcoholic steatohepatitis (NASH) were not different. In the multivariate analysis, SIBO (P=0.005) and the presence of a metabolic syndrome (P=0.006) were independent factors of severe hepatic steatosis. In morbidly obese patients, bacterial overgrowth prevalence is higher than in healthy subjects and is associated with severe hepatic steatosis.

BETA-ADRENERGIC BLOCKADE OF THE SYMPATHETIC NERVOUS SYSTEM DECELERATES PERIPORTAL FIBROSIS IN ABCB4 KNOCKOUT MICE

BACKGROUND AND AIM: Hepatic Stellate Cells (HSC) express α- and β-adrenoceptors and adrenergic inhibition results in reduced collagen I and α-smooth muscle actin (SMA) expression. Therefore, HSC were suggested to be the main cellular targets of sympathetic inhibition by β-blockers in experimental sinusoidal fibrosis. In order to study the role of the sympathetic nervous system in liver fibrogenesis we used the Abcb4 knock-out model developing non-HSC based, periportal fibrosis, which mimics primary sclerosing cholangitis (PSC).

Pro-Inflammatory and Pro-Coagulant Effects of Gemtuzumab Ozogamicin (Mylotarg®); Implications for the Development of VOD-Like Syndrome.

Gemtuzumab Ozogomicin (GO) is a humanized IgG4 anti-CD33 monoclonal antibody covalently linked to the powerful antitumour antibiotic, calicheamicin. CD33 expression is found on myeloid (mature and immature), erythroid, megakaryocytic, and multipotent progenitors but is absent from normal CD34+ pluripotent haematopoietic stem cells and non-haematopoietic tissues. GO has been used successfully in de novo and refractory/relapsed CD33+ AML, and in other CD33+ leukaemias, including ALL - the main rationale being it selectively targets the CD33+ blast population while sparing the CD33– haematopoietic stem cell compartment. Although myelosuppression is the main toxicity seen in the vast majority of patients (>95%) receiving GO at doses ranging from 6 to 9mg/m2, it is the liver injury, especially veno-occlusive disease (VOD)-like syndrome, that is unique and the most significant drug-related toxicity observed. Previous studies have shown that patients who develop VOD-like syndrome have higher circulating levels of pro-inflammatory cytokines and reduced levels of the natural anti-coagulants protein C and anti-thrombin, suggesting that a pro-inflammatory and pro-coagulant state is induced in the liver, however no specific mechanism has been elucidated to account for the liver toxicity. One possible explanation is that GO binds to CD33+ Kupffer cells and/or other CD33+ cells residing in the hepatic sinusoids and in doing so induces state of pro-inflammation and pro-coagulation which in turn causes the sinusoidal fibrosis, centrilobular congestion, and hepatocyte necrosis, the histological hallmark of this process. To investigate this possibility, the CD33+ AML cell line, THP1, and the CD33– hepatocyte cell line, HepG2, were treated with increasing concentrations of GO. Secreted levels of the pro-inflammatory cytokines TNF-α and IL-8 were measured by sandwich ELISA. Cell surface expression levels of Tissue Factor (TF), the critical initiator of the pro-coagulation pathway, were analysed by flow cytometry. Cell proliferation was measured by the WST-1 assay. A statistically significant (P<0.001) pro-coagulant but not pro-inflammatory response was observed following GO exposure in both cell lines. THP1 cells showed upregulation of TF expression after 24 hour incubation with GO but no significant increase in TNF-α or IL-8 levels. Neither cell line showed a significant change in proliferation levels after treatment with GO. These results suggest that the initial response to GO treatment is pro-coagulant. After the first treatment, there will be fewer CD33+ blast cells, leaving more GO molecules free to ligate to CD33+ targets in the liver, therefore repeated administration of the drug increases the pro-coagulant state and perpetuates the liver injury. Continuous injury of the liver initiates an inflammatory response through autocrine and paracrine loops. This serves as the initiation signal for fibrosis. If the cycle of inflammation and coagulation proceeds unchecked, the fibrogenic cascade is continued leading to the development of VOD-like syndrome.

Hepatic Microvasculature in Liver Injury

Injury to the hepatic microvasculature, the hepatic sinusoids, manifests in several ways. The sinusoidal endothelial cells (SECs) may lose porosity and scavenger function (capillarization); SECs may loosen from their tetherings to the space of Disse or even detach completely (ischemia-reperfusion injury, early sinusoidal obstruction syndrome, peliosis hepatis, early acetaminophen toxicity); the space of Disse may be completely denuded of sinusoidal lining cells that then embolize and obstruct the sinusoid (early sinusoidal obstruction syndrome); or the sinusoid may be obstructed by fibrosis (hepatic sinusoidal fibrosis, late sinusoidal obstruction syndrome). In many of these microvascular injuries, the change to the sinusoid is a primary event that may lead to hepatocyte hypoxia with liver dysfunction and disruption of the portal circulation. With the exception of hepatic fibrosis, which will be reviewed elsewhere in this issue, each of these types of microvascular injuries will be described in this article.

Hepatic fibrosis and cirrhosis in the Fontan circulation: a detailed morphological study

Aims:To describe the histological features of the liver in patients with a Fontan circulation.Methods:Specimens from liver biopsies carried out as part of preoperative assessment prior to extracardiac cavopulmonary conversion of...

Increased T-Cell Sinusoidal Lymphocytosis in Liver Biopsies in Patients With Chronic Hepatitis C and Mixed Cryoglobulinemia

Mixed cryoglobulinemia (MC) has a strong association with hepatitis C virus (HCV) infection and is associated with a higher degree of fibrosis and poor response to therapy. Currently, there are no known histological findings on liver biopsy that correlate with the presence of MC in HCV-infected patients, although we have occasionally noted prominent sinusoidal lymphocytosis in MC patients. The goal of this study is to determine whether sinusoidal lymphocytosis is a histological marker of MC in liver biopsies from patients with chronic hepatitis C. The liver clinic database at our institution was searched for chronic hepatitis C patients with MC who underwent liver biopsy during 1999-2005. Ten such cases were identified and were included in the study. Ten chronic hepatitis C MC-negative cases were matched for age and stage of fibrosis to serve as controls. Histological features (sinusoidal lymphocytes, inflammatory activity, acidophil bodies, and fibrosis stage) were evaluated in each biopsy. Clinical and laboratory data (serum protein electrophoresis, liver enzymes, hepatitis C viral load, treatment status, comorbidities, etc.) were also recorded. Formalin-fixed, paraffin-embedded sections were submitted for immunohistochemical analysis using antibodies against CD3, CD20, CD4, CD8, and CD68. Sinusoidal lymphocytes were counted in 5 hpf (40x) on hematoxylin and eosin (H&E) stain, and on CD3 and CD20 immunostains. The number of CD68+ Kupffer cells was also counted in a similar fashion. In the MC-positive versus MC-negative cases, mean fibrosis stage (2.4 vs. 2.4), inflammatory grade (1.7 vs. 2.1), lymphocyte count (359 vs. 128/5 hpf), and Kupffer cell count (239 vs. 220/5 HPF) were assessed. There was a significant increase in sinusoidal T-cell lymphocytes (P < 0.05) in MC-positive cases as compared to MC-negative cases. Nearly all sinusoidal lymphocytes were CD8-positive cells in both groups. Other histological parameters did not differ in the two groups. MC-positive cases tended to have a lower viral load as compared to controls (P= 0.059). The role of sinusoidal T cells in the pathogenesis of MC is currently unknown. It is unclear if the presence of these cells implies ongoing antigenic stimulation that may lead to increased risk of lymphoma. This feature may be an important clue to predict the presence of MC, an HCV-associated phenomenon that has important implications for response to treatment and disease progression.

Chronic Administration of Lipopolysaccharide and Proteases Induces Periodontal Inflammation and Hepatic Steatosis in Rats

Epidemiologic studies suggest a relationship between periodontitis and liver diseases. A rat periodontitis model was used to investigate whether a causal relationship exists between periodontitis and liver diseases. Fourteen male Wistar rats (8 weeks old) were divided into two groups: a periodontitis group in which Escherichia coli lipopolysaccharide (LPS) and Streptomyces griseus proteases were applied into the gingival sulcus for 8 weeks, and a control group using pyrogen-free water instead. After blood samples were collected, periodontal tissues and liver specimens were analyzed. Chronic administration of LPS and proteases to the gingival sulcus induced periodontitis and liver injury, including steatosis with inflammation and sinusoidal fibrosis. Apoptosis, enhanced concentration of 8-hydroxydeoxyguanosine, and activated production of tumor necrosis factor-alpha in liver were observed in the periodontitis group, with increased gingival inflammation, serum LPS, and reactive oxygen species. Periodontal inflammation in a rat model induced fatty liver disease through increased serum LPS.

Autoimmune Hepatitis: A Risk Factor for Cryptogenic Cirrhosis

Purpose: The etiology of cryptogenic cirrhosis (CC) is poorly understood. It is recognized that a significant number of patients with CC may result from nonalcoholic fatty liver disease (NAFLD) yet its cause in the others remains unknown. Occult autoimmune hepatitis or toxic liver injuries have been the other proposed causes of CC. The aim of the present study was to identify the clinical, biochemical, immunologic and histologic parameters of autoimmune hepatitis (AIH) in patients with CC to ascertain whether AIH is a causative risk factor for the disease. Methods: Thirty five consecutive patients who had liver transplant for CC were studied. Clinical, biochemical, immunologic and histologic parameters were analyzed and the International Autoimmune Hepatitis (IAH) score calculated. Explant histology was reevaluated by a hepatopathologist for the inflammation, lymphoid aggregate, plasma cells, interface hepatitis, steatosis, perivenular and sinusoidal changes, glycogenated nuclei, Mallory hyaline, bile duct changes, hepatocyte necrosis and fibrosis. Results: The mean age of patients was 53.7 ± 13 years, BMI was 29.6 ± 6.8 Kg M2 (range 21–42) and 57% were females. Diabetes was present in 42%; obesity in 63%, and 37% had concurrent illness. The liver chemistry revealed mild to moderate increase in aminotransferases (AST 85.5 ± 105, ALT 67 ± 70, AST/ALT 1.4 ± 0.6) and Alk Phos (187.7 ± 97.7). The ANA was positive in 17% and anti-smooth muscle antibody in 31%. Mean IAH score was 7.0 ± 3.0 and a score of 10 or greater was seen in 14%. However, in 60% of the patients with the high IAH score, the histologic features of residual NAFLD were also present. Liver histology showed cirrhosis in all. No interface hepatitis or plasma cell infiltrates were seen. Varying grades of centrivenular sclerosis (27 biopsies) and sinusoidal fibrosis (18 biopsies) indicative of residual NAFLD were seen in addition to Mallory hyaline seen in 23%. Conclusion: Occult or burnt-out AIH diagnosed by clinical, biochemical and immunologic criteria may be a risk factor leading to CC in a subset of patients. In some patients, dual injury from NAFLD and chronic AIH resulting in CC is a possibility. It remains conjectural that, the classic histology of AIH may be altered or lost once the disease progresses to cirrhotic stage.

Safety of neoadjuvant oxaliplatin-based chemotherapy (N-FOLFOX) in patients undergoing resection of colorectal liver metastases (R-CLM). Interim results

14550 Background: Oxaliplatin-5-fluorouracil-leucovorin (FOLFOX) has significant activity against CRC in both the metastatic and adjuvant settings. Consequently, neoadjuvant FOLFOX (N-FOLFOX) is being investigated in R-CLM. This has raised concerns regarding the safety and rate of post-operative complications (P-OCs) with N-FOLFOX, specifically, development of sinusoidal dilatation (SD), fibrosis and steatosis. This single-center cohort study was conducted to prospectively evaluate safety of N-FOLFOX in R-CLM patients. Methods: Planned total sample size is 40 patients [20 N-FOLFOX; 20 no chemotherapy (N-C)]. The N-C group consists of patients undergoing surgery for other hepatic pathology. Normal liver was examined by light (LM) and electron (EM) microscopy for SD, perisinusoidal fibrosis, and steatosis/necrosis; severity was graded from 0 (absent) to 2. The rate of P-OCs, hospital stays, and liver function tests (LFTs) were assessed. Results: At the time of this analysis, 20 patients (10 N-FOLFOX; 10 N-C) have undergone surgery. In the N- FOLFOX group, median number of cycles of N-FOLFOX was 6, with 2 patients receiving only 4 cycles. The median time between completion of N-FOLFOX and surgery was 6 weeks. There were no statistical differences between N-FOLFOX and N-C groups in potentially confounding factors, including previous chemotherapy, alcohol consumption, medical history, or concomitant medications. Number of patients with SD was 8 in each group (all were grade 1 except for 1 patient in N-C who had grade 2). Steatosis was seen in 7 and 6 patients in N-FOLFOX, and N-C groups, respectively (2 patients in each group were grade 2; remaining were grade 1). Fibrosis was noted in only 1 patient in N-C group. No nodular regeneration was observed in either group. There was a subjective loss on EM of mitochondria and Golgi apparatus/body with N-FOLFOX. Median post-operative hospital stay was 12 days in both groups. Conclusions: N-FOLFOX appears to have no clinically significant deleterious effects on normal liver architecture, function, or recovery post-surgery in R-CLM patients. The study is ongoing to accrue up to 40 patients; updated data will be presented. No significant financial relationships to disclose.

Early histologic changes in fibrosing cholestatic hepatitis C

Recurrent hepatitis C (RHCV) after liver transplantation is almost universal, and occasional patients will have an aggressive course characterized histologically by pericellular/sinusoidal fibrosis and cholestasis, known as fibrosing cholestatic hepatitis (FCH). The early stages and evolution of this disease have not been well characterized. A total of 77 liver biopsies performed for indication (nonprotocol) were evaluated for necroinflammation, rejection, cholestasis, and fibrosis. Control groups were composed of protocol biopsies from HCV transplant patients (10 biopsies) as well as non-HCV transplant patients (6 biopsies). Scoring for necroinflammation, rejection, and fibrosis were compiled using standard criteria (hepatic activity index, Banff, Ishak, METAVIR). Pericellular fibrosis was staged with a novel "sinusoidal" system. A cholestasis scoring system was developed to quantitate parenchymal and portal features of cholestasis. Biopsies were categorized as rejection, RHCV, FCH, and stable based on histology and clinical information. FCH was found to have a higher fibrosis stage overall when compared to most diagnostic groups, regardless of the staging system used. Additionally, sinusoidal fibrosis was significantly higher in the FCH diagnosis group. Cholestasis was more prominent in biopsies of FCH in all comparisons. In conclusion, the presence of cholestasis and fibrosis with mild to moderate RHCV should raise the suspicion of FCH. When studying the evolution of these cases, the first abnormality to appear is RHCV and cholestasis, fibrosis develops soon after, and both continue to worsen until the point of allograft failure or patient death.

Transjugular Intrahepatic Portosystemic Shunt for the Treatment of Portal Hypertension Due to Idiopathic Myelofibrosis

A 59-year-old man was diagnosed to have idiopathic myelofibrosis (IMF) in November 2001. In April 2004, massive ascites and esophageal varices were found. IMF was considered to be the cause of portal hypertension (ascites and esophageal varices). Since ascites tend to be intractable with diuretic drugs, a transjugular intrahepatic portosystemic shunt (TIPS) was inserted in May 2004. Before TIPS, his waist measured 98 cm. On day 74 after TIPS, his waist measured 68 cm as a result of the administration of diuretic drugs alone. He eventually died due to hepatic failure on day 168 after TIPS. The autopsy findings suggest that sinusoidal fibrosis caused portal hypertension.

HYDROPS FETALIS IN A NEONATE WITH DOWN SYNDROME, TRANSIENT MYELOPROLIFERATIVE DISORDER AND HEPATIC FIBROSIS

Transient myeloproliferative disorder is a self limiting disorder characterized by leukocytosis with the presence of megakaryoblasts in the peripheral blood and bone marrow, anemia, thrombocytopenia, and organomegaly. It occurs in approximately 10% of newborn infants with Down syndrome. Hepatic fibrosis is seen in the severe form of transient myeloproliferative disorder with Down syndrome that is characterized by diffuse intralobular sinusoidal fibrosis and extramedullary hematopoesis. We describe a patient with hydrops fetalis, Down syndrome, and transient myeloproliferative disorder. We suggest that patients with the severe form of transient myeloproliferative disorder should be examined for hepatic fibrosis.

Segmental Budd Chiari Syndrome

Segmental hepatic ischemia following placement of transjugular intrahepatic portosystemic shunt (TIPS) is extremely rare (only 2 cases previously described in literature) and thought to be due to thrombosis of the hepatic vein above the stent graft. We describe a case of segmental Budd Chiari Syndrome (BCS) developing following TIPS placement for ascites in a patient with veno-occlusive disease (VOD). A 65 year-old Caucasian male with acute myelogenous leukemia relapsed and was treated with salvage Gemtuzumab (Mylotarg) and subsequent allogenic stem-cell transplant 4 years prior to presentation. Post-transplant course was complicated by chronic graft-versus-host disease (GVHD) involving skin, lung, and liver. Five months prior to admission, he noted an increase in abdominal girth and lower extremity edema. Over the next several months, the ascites increased requiring multiple paracenteses (SAAG>1.1) and became refractory to diuretic therapy. A transjugular liver biopsy showed a hepatic venous wedge gradient of 25mmHg and marked sinusoidal fibrosis, hepato-portal sclerosis, and mild GVHD consistent with VOD. In view of the post sinusoidal outflow obstruction, relatively good liver synthetic function, and since the patient was not a transplant candidate, TIPS was placed from middle hepatic vein to the left portal vein for the management of ascites. Ultrasound performed the following day confirmed patency of TIPS. The patient's ascites improved immediately following TIPS. Two days later, he was found to have an acute worsening of his transaminases with AST of 432 and ALT of 1169 u/l with normal bilirubin. CT scan showed a wedge-shaped hypodense region in left hepatic lobe consistent with ischemia. Branches of the hepatic artery and portal vein were patent within the affected liver segment. The middle hepatic vein was not clearly visualized, and given the distribution of the ischemia was likely thrombosed. He was managed conservatively with hydration and monitoring and transaminases improved over the next few days. However, he developed respiratory decompensation and eventually, multi-organ system failure. His family opted to withdraw further care. No autopsy was performed. We present a case of segmental BCS – an extremely rare complication of TIPS which can be diagnosed on imaging when there is a high index of clinical suspicion (high transaminases post procedure in the absence of other causes). It is generally self limited and managed conservatively.

A Report of the Vancouver Forum on the Care of the Live Organ Donor: Lung, Liver, Pancreas, and Intestine Data and Medical Guidelines

An international conference of transplant physicians, surgeons, and allied health professionals was held in Vancouver, Canada, on September 15 and 16, 2005 to address the care of the live lung, liver, pancreas, and intestine organ donor. The Vancouver Forum was convened under the auspices of the Ethics Committee of The Transplantation Society. Forum participants included over 100 leaders in organ transplantation, representing many countries from around the world, including participants from the following continents: Africa, Asia, Australia, Europe, North and South America. The objective of the Vancouver Forum was to develop an international standard of care for the live lung, liver, pancreas and intestinal organ donor. This Vancouver Forum followed a conference convened in Amsterdam on the care of the live kidney donor (1, 2). There were four organ specific work groups at the Vancouver Forum: lung, liver, pancreas and intestine. Each organ work group addressed the following topics in concert and reported their findings in a plenary presentation to all participants:

Hypervitaminosis A‐induced liver fibrosis: stellate cell activation and daily dose consumption

Hypervitaminosis A-related liver toxicity may be severe and may even lead to cirrhosis. In the normal liver, vitamin A is stored in hepatic stellate cells (HSC), which are prone to becoming activated and acquiring a myofibroblast-like phenotype, producing large amounts of extracellular matrix. In order to assess the relationship between vitamin A intake, HSC activation and fibrosis, we studied nine liver biopsies from patients belonging to a well-characterized series of 41 patients with vitamin A hepatotoxicity. Fibrosis was underlined by Sirius-red staining, whereas activated HSC were immunohistochemically identified using an antibody against alpha smooth muscle actin. The volume density (Vv) of sinusoidal and total fibrosis and of sinusoidal and total activated HSC was quantified by the point-counting method. Morphology ranged from HSC hypertrophy and hyperplasia as the sole features to severe architectural distortion. There was a significant positive correlation between Vv of perisinusoidal fibrosis and the daily consumption of vitamin A (P=0.004). The close correlation between the severity of perisinusoidal fibrosis and the daily dose of the retinol intake suggests the existence of a dose-effect relationship.

P.424 Metformin in the treatment of non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of clinicopatholologic conditions ranging from steatosis alone to nonalcoholic steatohepatitis (NASH), with varying risks for progression to cirrhosis. Although steatosis alone seems to be nonprogressive, some patients with NASH can progress. This study focuses on the clinical and pathological characteristics of patients with NAFLD associated with the development of histological fibrosis. Patients with an established diagnosis of nonalcoholic fatty liver were identified through our NAFLD database containing extensive clinical, demographic, and laboratory data. Liver biopsy specimens were read blindly by one hepatopathologist using a 19-item pathological protocol and by another hepatopathologist using a second pathological protocol. Clinical and pathological data were matched to the presence of different types of histological fibrosis. Univariate and multivariate analyses helped determine all of the variables independently associated with histological fibrosis. Of 132 NAFLD patients, 21.2% had advanced fibrosis (septal/bridging fibrosis or well-established cirrhosis). Sinusoidal fibrosis was present in 20.3% of patients, whereas perivenular fibrosis was seen in 17.2%. Ballooning degeneration and Mallory bodies were independently associated with both sinusoidal fibrosis and perivenular fibrosis. Aspartate aminotransferase/alanine aminotransferase ratio and ballooning degeneration were also independently associated with periportal-portal fibrosis. We conclude that the presence of hepatocyte injury in NAFLD is associated with fibrosis. These pathological features can be used to establish the pathological criteria for diagnosis of the progressive form of NAFLD or NASH.

Diabetic Hepatosclerosis: Diabetic Microangiopathy of the Liver

Liver disease associated with diabetes mellitus is common and usually takes the form of simple steatosis or nonalcoholic steatohepatitis. After observing a noncirrhotic form of hepatic sinusoidal fibrosis in patients with long-standing diabetes mellitus who underwent liver biopsy, we set about to characterize this novel entity. Cases with the hallmark histologic findings were gathered at Saint Louis University School of Medicine and the Armed Forces Institute of Pathology. The clinical records were examined in a systematic fashion. Results of light microscopy and prepared immunohistochemical stains were reviewed. Clinical findings of patients with the histologic, detailed light microscopic, and immunohistochemical findings on biopsies. Twelve patients were identified from biopsy findings; all had a history of long-standing diabetes mellitus and a noncirrhotic form of hepatic sinusoidal fibrosis not associated with nonalcoholic steatohepatitis. Most of these patients had a body mass index less than 25 kg/m2 and had substantial evidence of microvascular complications, including retinopathy, nephropathy, and peripheral and autonomic neuropathy. Alkaline phosphatase elevation was common. Liver biopsy specimens showed extensive dense perisinusoidal fibrosis, and immunostaining revealed basement membrane components in a perisinusoidal distribution. Features of nonalcoholic steatohepatitis were not present in the biopsy specimens. We propose the term diabetic hepatosclerosis for this entity and suggest that it represents a form of diabetic microangiopathy affecting the liver. Further studies are needed to precisely characterize diabetic hepatosclerosis and to understand mechanisms of pathogenesis and the clinical significance.