Stefan G. Hubscher

Histological assessment of non-alcoholic fatty liver disease

Non‐alcoholic fatty liver disease (NAFLD) is an important complication of the metabolic syndrome, which is becoming an increasingly common cause of chronic liver disease. Histological changes typically mainly affect perivenular regions of the liver parenchyma and include an overlapping spectrum of steatosis, steatohepatitis and persinusoidal or pericellular fibrosis, in some cases leading to cirrhosis. Once cirrhosis has developed, typical hepatocellular changes are often no longer conspicuous, leading to such cases being mistakenly diagnosed as ‘cryptogenic’. Portal inflammation, ductular reaction and periportal fibrosis can also be seen as part of the morphological spectrum of NAFLD, particularly in the paediatric population. Hepatocellular carcinoma has also been described as a complication of NAFLD‐associated cirrhosis. NAFLD is also an important cofactor in other chronic liver diseases, especially hepatitis C. Histological assessments have an important role to play in the diagnosis and management of NAFLD. These include making the potentially important distinction between simple steatosis and steatohepatitis and providing pointers to the aetiology, including cases where a dual pathology exists. A number of systems have been devised for grading and staging the severity of fatty liver disease. These require further evaluation, but have a potentially important role to play in determining prognosis and monitoring therapeutic responses.

Hepatic Endothelial CCL25 Mediates the Recruitment of CCR9+ Gut-homing Lymphocytes to the Liver in Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC), a chronic inflammatory liver disease characterized by progressive bile duct destruction, develops as an extra-intestinal complication of inflammatory bowel disease (IBD) (Chapman, R.W. 1991. Gut. 32:1433–1435). However, the liver and bowel inflammation are rarely concomitant, and PSC can develop in patients whose colons have been removed previously. We hypothesized that PSC is mediated by long-lived memory T cells originally activated in the gut, but able to mediate extra-intestinal inflammation in the absence of active IBD (Grant, A.J., P.F. Lalor, M. Salmi, S. Jalkanen, and D.H. Adams. 2002. Lancet. 359:150–157). In support of this, we show that liver-infiltrating lymphocytes in PSC include mucosal T cells recruited to the liver by aberrant expression of the gut-specific chemokine CCL25 that activates α4β7 binding to mucosal addressin cell adhesion molecule 1 on the hepatic endothelium. This is the first demonstration in humans that T cells activated in the gut can be recruited to an extra-intestinal site of disease and provides a paradigm to explain the pathogenesis of extra-intestinal complications of IBD.

Progressive histological damage in liver allografts following pediatric liver transplantation

The long‐term histological outcome after pediatric liver transplantation (OLT) is not yet fully understood. De novo autoimmune hepatitis, consisting of histological chronic hepatitis associated with autoantibody formation and allograft dysfunction, is increasingly recognized as an important complication of liver transplantation, particularly in the pediatric population. In this study, 158 asymptomatic children with 5‐year graft survival underwent protocol liver biopsies (113, 135, and 64 at 1, 5, and 10 years after OLT, respectively). Histological changes were correlated with clinical, biochemical, and serological findings. All patients received cyclosporine A as primary immunosuppression with withdrawal of corticosteroids at 3 months post OLT. Normal or near‐normal histology was reported in 77 of 113 (68%), 61 of 135 (45%), and 20 of 64 (31%) at 1, 5, and 10 years, respectively. The commonest histological abnormality was chronic hepatitis (CH), the incidence of which increased with time [25/113 (22%), 58/135 (43%), and 41/64 (64%) at 1, 5, and 10 years, respectively) (P < .0001)]. The incidence of fibrosis associated with CH increased with time [13/25 (52%), 47/58 (81%), and 37/41 (91%) at 1, 5, and 10 years, respectively) (P < .0001)]. The severity of fibrosis associated with CH also increased with time, such that by 10 years 15% had progressed to cirrhosis. Aspartate aminotransferase (AST) levels were slightly elevated in children with CH (median levels 52 IU/L, 63 IU/L, and 48 IU/L at 1, 5, and 10 years, respectively), but this did not reach statistical significance compared with those with normal histology. On multivariate analysis, the only factor predictive of chronic hepatitis was autoantibody positivity (present in 13% and 10% of children with normal biopsies at 5 and 10 years, respectively, and 72% and 80% of those with CH at 5 and 10 years, respectively) (P < .0001). Four children with CH and autoantibodies, who also had raised immunoglobulin G (IgG) levels and AST greater than 1.5× normal fulfilled the diagnostic criteria for de novo autoimmune hepatitis (AIH). Another two were found to be hepatitis C positive. No definite cause for CH could be identified in the other cases. In conclusion, chronic hepatitis is a common finding in children after liver transplantation and is associated with a high risk of developing progressive fibrosis, leading to cirrhosis. Standard liver biochemical tests cannot be relied on either in the diagnosis or in the monitoring of progress of chronic allograft hepatitis. In contrast, the presence of autoantibodies is strongly associated with the presence of CH. The cause of chronic hepatitis in transplanted allografts is uncertain but may be immune mediated, representing a hepatitic form of chronic rejection. (HEPATOLOGY 2006;43:1109–1117.)

INTERCELLULAR ADHESION MOLECULE 1 ON LIVER ALLOGRAFTS DURING REJECTION

The expression of intercellular adhesion molecule 1 (ICAM-1), a ligand for the leucocyte adhesion receptor lymphocyte-function-associated antigen 1 (LFA-1), was studied on liver tissue after transplantation. There was greater ICAM-1 expression on bile ducts, endothelium, and perivenular hepatocytes (structures affected by the rejection process) in patients with acute rejection than in donor livers, patients with stable transplants, or patients with non-rejection complications. The expression on bile ducts and hepatocytes was greater in patients in whom there was progression to chronic, irreversible rejection. In patients with resolving rejection ICAM-1 expression was greatly reduced after high-dose corticosteroid treatment. The expression in patients with non-rejection complications and in those with long-term stable grafts was similar to that seen in the donor controls. The induction of ICAM-1 on tissues may be an important step in the development of the inflammatory response of rejection and in determining which cells are the targets of immune damage. The reduction of ICAM-1 expression seen after successful treatment with high-dose corticosteroids suggests that this might be an important mode of action of these drugs.

A re‐evaluation of the risk factors for the recurrence of primary sclerosing cholangitis in liver allografts

Previously, we have found that the absence of the colon after liver transplantation (LT) protects the patient from recurrent primary sclerosing cholangitis (rPSC). As our previous observation has not been confirmed in other series, we have reviewed our cohort of patients grafted for primary sclerosing cholangitis (PSC) with greater numbers and longer follow‐up to reassess the rate, consequences, and risk factors for rPSC. We collected data on patients who underwent LT for PSC between January 1986 and April 2006. Data were collected for cytomegalovirus status, inflammatory bowel disease status, time of colectomy, type of colectomy, donor‐recipient gender mismatch, recipient sex, extended donor criteria (EDC), and donor risk index. Accepted criteria were used to diagnose rPSC. Of a total of 230 consecutive adult patients, 61 (27%) underwent colectomy pre‐/peri‐LT, and 54 (23.5%) developed rPSC at a median of 4.6 (range, 0.5–12.9) years post‐LT. A total of 263 deceased donor grafts were used, and 73 were EDC grafts. A diagnosis of rPSC was made in 61 of the 263 grafts (23%). The recurrence‐free patient survival was significantly better (P < 0.05) in patients who underwent pre‐/peri‐LT colectomy and in those with non‐EDC grafts. In conclusion, in this larger cohort of 230 patients and with longer follow‐up of 82.5 (range, 0.0–238.6) months [in comparison with the previous report of 152 recipients with a follow‐up of 52.8 (range, 1–146) months], we have shown that colectomy remains a significant risk factor for rPSC and that colectomy before and during initial LT for PSC confers a protective effect against rPSC in subsequent graft(s). Moreover, we have shown that EDC grafts are also a significant risk factor for rPSC. Liver Transpl 15:330–340, 2009.

CD81 and Claudin 1 Coreceptor Association: Role in Hepatitis C Virus Entry

ABSTRACT Hepatitis C virus (HCV) is an enveloped positive-stranded RNA hepatotropic virus. HCV pseudoparticles infect liver-derived cells, supporting a model in which liver-specific molecules define HCV internalization. Three host cell molecules have been reported to be important entry factors or receptors for HCV internalization: scavenger receptor BI, the tetraspanin CD81, and the tight junction protein claudin-1 (CLDN1). None of the receptors are uniquely expressed within the liver, leading us to hypothesize that their organization within hepatocytes may explain receptor activity. Since CD81 and CLDN1 act as coreceptors during late stages in the entry process, we investigated their association in a variety of cell lines and human liver tissue. Imaging techniques that take advantage of fluorescence resonance energy transfer (FRET) to study protein-protein interactions have been developed. Aequorea coerulescens green fluorescent protein- and Discosoma sp. red-monomer fluorescent protein-tagged forms of CD81 and CLDN1 colocalized, and FRET occurred between the tagged coreceptors at comparable frequencies in permissive and nonpermissive cells, consistent with the formation of coreceptor complexes. FRET occurred between antibodies specific for CD81 and CLDN1 bound to human liver tissue, suggesting the presence of coreceptor complexes in liver tissue. HCV infection and treatment of Huh-7.5 cells with recombinant HCV E1-E2 glycoproteins and anti-CD81 monoclonal antibody modulated homotypic (CD81-CD81) and heterotypic (CD81-CLDN1) coreceptor protein association(s) at specific cellular locations, suggesting distinct roles in the viral entry process.

Risk factors for recurrence of primary sclerosing cholangitis of liver allograft

Primary sclerosing cholangitis (PSC) is a disease of unknown cause that effects the biliary tree and is closely associated with inflammatory bowel disease. We did a retrospective analysis of the risk factors associated with recurrence of PSC in an allograft after liver transplantation. Recurrence of disease, assessed by liver histology or imaging the biliary tree, occurred in 56 of 152 patients (37%) at a median of 36 months (range 1.4-120 months). Multivariate analysis showed that being male (relative risk 1.2, 95% CI 0.73-2.15) and an intact colon before transplantation (8.7, 1.19-64.48) were associated with recurrence. These observations could help elucidate the pathogenesis of the disease.

Lamivudine without HBIg for prevention of graft reinfection by hepatitis B: Long-term follow-up

Background. This open, multicenter study was conducted to evaluate the efficacy and safety of lamivudine prophylaxis given to chronic hepatitis B virus- (HBV) infected patients before and after orthotopic liver transplantation (OLT).We now present long-term data that follow our previous short-term report. Methods. Twenty-three patients were treated with lamivudine (100 mg orally, daily); 13 (57%), were serum HBV DNA positive (Abbott Genostics, Abbott Laboratories, Chicago, IL) at study entry. Patients received lamivudine for at least 4 weeks before OLT, and for up to 50 months (median 25 months) after OLT. Results. Of the 23 treated patients, 17 survived to undergo OLT. Eleven patients (65%) survived up to 4 years (median 36 months) after OLT. One of the survivors stopped lamivudine because of a possible adverse reaction 9 months post-OLT, and prophylaxis with HBV immune globulin was then established. Ten survivors continue lamivudine. Eight long-term survivors have normal liver function without evidence of HBV reinfection. Of the 17 transplanted patients, 6 died. Four patients died (3 days to 5 months post-OLT) without evidence of graft reinfection. Two further patients died at 19 and 23 months post-OLT from graft failure. Both patients had YMDD variant detected at 12 months post-OLT. Two other patients with YMDD-variant HBV remain alive on lamivudine, 9 and 15 months after development of the variant. Conclusions. Lamivudine, given before and after OLT, prevents significant graft reinfection for the majority of treated patients. The study has also shown that lamivudine is extremely well tolerated by liver failure patients and for a prolonged period after transplantation.

Hepatic Expression of Secondary Lymphoid Chemokine (CCL21) Promotes the Development of Portal-Associated Lymphoid Tissue in Chronic Inflammatory Liver Disease

The chronic inflammatory liver disease primary sclerosing cholangitis (PSC) is associated with portal inflammation and the development of neolymphoid tissue in the liver. More than 70% of patients with PSC have a history of inflammatory bowel disease and we have previously reported that mucosal addressin cell adhesion molecule-1 is induced on dendritic cells and portal vascular endothelium in PSC. We now show that the lymph node-associated chemokine, CCL21 or secondary lymphoid chemokine, is also strongly up-regulated on CD34(+) vascular endothelium in portal associated lymphoid tissue in PSC. In contrast, CCL21 is absent from LYVE-1(+) lymphatic vessel endothelium. Intrahepatic lymphocytes in PSC include a population of CCR7(+) T cells only half of which express CD45RA and which respond to CCL21 in migration assays. The expression of CCL21 in association with mucosal addressin cell adhesion molecule-1 in portal tracts in PSC may promote the recruitment and retention of CCR7(+) mucosal lymphocytes leading to the establishment of chronic portal inflammation and the expanded portal-associated lymphoid tissue. This study provides further evidence for the existence of portal-associated lymphoid tissue and is the first evidence that ectopic CCL21 is associated with lymphoid neogenesis in human inflammatory disease.

Recurrence of autoimmune hepatitis after liver transplantation.

BACKGROUND The literature data on the recurrence of autoimmune hepatitis (AIH) after orthotopic liver transplantation (OLTX) is scanty. METHODS We analyzed the frequency of recurrent AIH in 47 patients who had been transplanted for AIH and survived at least 1 year after surgery. The following criteria were applied to diagnose recurrence: (1) positive autoantibodies in the titer> or =1:40; (2) hypertransaminasemia; (3) histological features of chronic hepatitis; (4) need of reintroduction or significant increase of steroids; and (5) lack of serum markers of viral hepatitis. RESULTS A total of 13 patients (1 male/12 females) developed recurrent AIH after an interval of 6-63 months after OLTX (mean 29 months). Mean AST level at recurrence was 542+/-129 U/L. Three patients from this group needed regrafting. Mismatch of DR3+ recipient and DR3- donor was not more common in the recurrent disease group (37%) compared to the nonrecurrence group (31%) (P=NS). CONCLUSIONS Recurrence of AIH after OLTX was diagnosed in a high proportion of patients and some of them required regrafting. DR3+ patients are not particularly prone to develop recurrence.