Oyedele Adeyi

Antiviral treatment of recurrent hepatitis C after liver transplantation: predictors of response and long-term outcome.

Background. Efficacy and long-term outcome of antiviral therapy for recurrent hepatitis C after liver transplantation is poorly defined. Aim. This study aimed at assessing the efficacy of antiviral therapy regarding sustained hepatitis C virus (HCV) clearance, liver histology, and patient survival. Methods. We retrospectively reviewed all 446 patients who received a liver allograft at our institution for HCV-related cirrhosis between January 1992 and December 2006. Two hundred thirty-two patients (52%) were eligible for antiviral therapy based on predefined criteria (Metavir stage ≥1 and/or grade ≥2; protocol biopsies). One hundred seventy-two patients (39%) had no contraindication for treatment, received more than or equal to 1 dose of interferon-&agr;–based combination therapy, and form the basis of this analysis. Therapy was aimed for 48 weeks; median posttreatment follow-up was 68 months. Results. The overall sustained virological response (SVR) rate was 50% (genotype 1/4: 40%; genotype 2/3: 76%). SVR was higher on cyclosporine A (CsA) (56%) than on tacrolimus (44%, P=0.05), largely because of a lower relapse rate (6% vs. 19%, P=0.01). In multivariate analysis, genotype 2/3, CsA use, donor age, and pretreatment necroinflammatory activity were independently associated with SVR. SVR significantly improved histology and long-term survival (actuarial 5-year survival 96% vs. 69% in nonresponders, P<0.0001). Conclusion. Antiviral therapy of recurrent hepatitis C after liver transplantation is able to clear HCV in half the patients, more likely on CsA than on tacrolimus, and markedly improves outcome.

Normothermic Acellular Ex Vivo Liver Perfusion Reduces Liver and Bile Duct Injury of Pig Livers Retrieved After Cardiac Death

We compared cold static with acellular normothermic ex vivo liver perfusion (NEVLP) as a novel preservation technique in a pig model of DCD liver injury. DCD livers (60 min warm ischemia) were cold stored for 4 h, or treated with 4 h cold storage plus 8 h NEVLP. First, the livers were reperfused with diluted blood as a model of transplantation. Liver injury was determined by ALT, oxygen extraction, histology, bile content analysis and hepatic artery (HA) angiography. Second, AST levels and bile production were assessed after DCD liver transplantation. Cold stored versus NEVLP grafts had higher ALT levels (350 ± 125 vs. 55 ± 35 U/L; p < 0.0001), decreased oxygen extraction (250 ± 65 mmHg vs. 410 ± 58 mmHg, p < 0.01) and increased hepatocyte necrosis (45% vs. 10%, p = 0.01). Levels of bilirubin, phospholipids and bile salts were fivefold decreased, while LDH was sixfold higher in cold stored versus NEVLP grafts. HA perfusion was decreased (twofold), and bile duct necrosis was increased (100% vs. 5%, p < 0.0001) in cold stored versus NEVLP livers. Following transplantation, mean serum AST level was higher in the cold stored versus NEVLP group (1809 ± 205 U/L vs. 524 ± 187 U/L, p < 0.05), with similar bile production (2.5 ± 1.2 cc/h vs. 2.8 ± 1.4 cc/h; p = 0.2). NEVLP improved HA perfusion and decreased markers of liver duct injury in DCD grafts.

Mechanism of hard-nanomaterial clearance by the liver

The liver and spleen are major biological barriers to translating nanomedicines because they sequester the majority of administered nanomaterials and prevent delivery to diseased tissue. Here we examined the blood clearance mechanism of administered hard nanomaterials in relation to blood flow dynamics, organ microarchitecture, and cellular phenotype. We found that nanomaterial velocity reduces 1000-fold as they enter and traverse the liver, leading to 7.5 times more nanomaterial interaction with hepatic cells relative to peripheral cells. In the liver, Kupffer cells (84.8%±6.4%), hepatic B cells (81.5±9.3%), and liver sinusoidal endothelial cells (64.6±13.7%) interacted with administered PEGylated quantum dots but splenic macrophages took up less (25.4±10.1%) due to differences in phenotype. The uptake patterns were similar for two other nanomaterial types and five different surface chemistries. Potential new strategies to overcome off-target nanomaterial accumulation may involve manipulating intra-organ flow dynamics and modulating cellular phenotype to alter hepatic cell interaction.

2016 Comprehensive Update of the Banff Working Group on Liver Allograft Pathology: Introduction of Antibody-Mediated Rejection

The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody‐mediated liver allograft rejection at the 11th (Paris, France, June 5–10, 2011), 12th (Comandatuba, Brazil, August 19–23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5–10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody‐mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.

The Difference in the Fibrosis Progression of Recurrent Hepatitis C After Live Donor Liver Transplantation Versus Deceased Donor Liver Transplantation Is Attributable to the Difference in Donor Age

Hepatitis C recurs universally after liver transplantation (LT). Whether its progression differs after live donor liver transplantation (LDLT) and deceased donor liver transplantation (DDLT) is still debated. We retrospectively analyzed 201 consecutive LTs performed at our institution for hepatitis C–related end‐stage liver disease between April 2000 and December 2005 (46 LDLTs and 155 DDLTs). Patients were followed with protocol biopsies for medians of 29 (LDLT) and 39 months (DDLT; P = 0.7). Although overall graft and patient survival did not differ, the mean fibrosis stage (Metavir) was significantly higher at 12 to 48 months post‐LT (all P < 0.05), and the rate of fibrosis progression tended to be faster after DDLT than LDLT (0.19 versus 0.11 stage/year, P = 0.05). In univariate analysis, donor age, cold ischemic time, and DDLT were significantly associated with a fibrosis stage ≥ 1 at 1 year and a fibrosis stage of 3 or 4 at 2 years post‐LT. In multivariate analysis, however, donor age was the sole variable independently associated with both surrogate outcomes. Thus, donor age > 45 years carried a relative risk of 8.17 (confidence interval = 2.6–25.5, P = 0.001) for reaching fibrosis stage 3 or 4 at 2 years post‐LT. In conclusion, donor age, rather than the transplant approach, determines the progression of recurrent hepatitis C after LT. LDLT, allowing for the selection of younger donors, may particularly benefit hepatitis C patients. Liver Transpl 14:1778–1786, 2008.

CD154 on the surface of CD4+CD25+ regulatory T cells contributes to skin transplant tolerance.

Background. It is known that the infusion of whole blood from donors (donor-specific transfusion) into recipients combined with anti-CD154 therapy can prolong allograft survival. It has generally been agreed that the effectiveness of anti-CD154 therapy is caused by the inactivation of alloreactive CD4+ and CD8+ effector T cells. The recent literature has implicated CD4+CD25+ regulatory T cells in the suppression of autoimmunity and graft rejection, and we therefore examined whether CD154 blockade is effective because of its blockade of inflammatory T-cell activation or because of a direct impact on the regulatory T cells. Methods. RAG-/- mice were adoptively transfused with CD4+ T cells or a subset of the population (CD4+CD25+ or CD4+CD25− T cells) alone or in combination with donor-specific transfusion and anti-CD154 and given an allo-skin transplant. The longevity of the transplant was determined over time. CD154-/-CD4+ T cells were used to assess the importance of CD154 in graft rejection and acceptance. Results. CD154 blockade (or loss of CD154) on CD4+CD25+ regulatory T cells enhanced their immunosuppressive activities and was a contributing factor to anti-CD154–induced immune suppression in vivo. In a model of allograft tolerance, suppression was elicited by antigen and anti-CD154 or antigen alone if the CD4+CD25+ regulatory T cells were deficient in CD154 expression. Conclusions. Neutralizing the function of CD154 on regulatory T cells upon antigen exposure induces heightened levels of suppressive activities and is likely a contributing factor to the long-lived therapeutic effects of anti-CD154 treatment.

The novel CD4+CD25+ regulatory T cell effector molecule fibrinogen-like protein 2 contributes to the outcome of murine fulminant viral hepatitis.

Fulminant viral hepatitis (FH) remains an important clinical problem in which the underlying pathogenesis is not well understood. Here, we present insight into the immunological mechanisms involved in FH caused by murine hepatitis virus strain 3 (MHV‐3), indicating a critical role for CD4+CD25+ regulatory T cells (Tregs) and production of the novel Treg effector molecule FGL2. Before infection with MHV‐3, susceptible BALB/cJ mice had increased numbers of Tregs and expression of fgl2 messenger RNA (mRNA) and FGL2 protein compared with resistant A/J mice. After MHV‐3 infection, plasma levels of FGL2 in BALB/cJ mice were significantly increased, correlating with increased percentage of Tregs. Treatment with anti‐FGL2 antibody completely inhibited Treg activity and protected susceptible BALB/cJ mice against MHV‐3‐liver injury and mortality. Adoptive transfer of wild‐type Tregs into resistant fgl2−/− mice increased their mortality caused by MHV‐3 infection, whereas transfer of peritoneal exudate macrophages had no adverse effect. Conclusion: This study demonstrates that FGL2 is an important effector cytokine of Tregs that contributes to susceptibility to MHV‐3–induced FH. The results further suggest that targeting FGL2 may lead to the development of novel treatment approaches for acute viral hepatitis infection. (HEPATOLOGY 2009.)

Liver allograft pathology: approach to interpretation of needle biopsies with clinicopathological correlation

The spectrum of diseases encountered in post-transplant liver pathology biopsies is broad. In this review, these have been divided as belonging to one of three categories: (1) new-onset/de novo post-transplant abnormalities (early and late), (2) rejection, and (3) recurrence of original disease. The clinical and pathological features of the entities making up each category, with the relevant differential diagnosis and overlaps between and within these groups, are discussed and illustrated. Recurrent or de novo neoplasms make up a fourth category not included in this review. Early new-onset conditions are mostly related to surgical complications, donor factors and ischaemia to the graft. These include reperfusion/preservation injury, lipopeliosis, small-for-size-syndrome, biliary sludge syndrome and hepatic artery thrombosis. The various forms of rejection (cellular, chronic, antibody-mediated, and late atypical rejection) are detailed. Most chronic liver diseases can and do recur in the graft. They may display features that overlap with de novo conditions (eg, primary sclerosing cholangitis versus chronic rejection). As with most cases of allograft biopsy interpretation, accurate diagnosis rests with careful correlation of histological features with clinical, imaging and laboratory findings, and often comparison with previous sequential and follow-up biopsies. Late-onset new diseases include biliary strictures, idiopathic chronic hepatitis and de novo autoimmune hepatitis, among others. This review provides a practical approach to the interpretation of these challenging biopsies. Selected difficult scenarios or conundrums are identified and discussed in the relevant sections.

Subnormothermic ex vivo liver perfusion reduces endothelial cell and bile duct injury after donation after cardiac death pig liver transplantation

An ischemic‐type biliary stricture (ITBS) is a common feature after liver transplantation using donation after cardiac death (DCD) grafts. We compared sequential subnormothermic ex vivo liver perfusion (SNEVLP; 33°C) with cold storage (CS) for the prevention of ITBS in DCD liver grafts in pig liver transplantation (n = 5 for each group). Liver grafts were stored for 10 hours at 4°C (CS) or preserved with combined 7‐hour CS and 3‐hour SNEVLP. Parameters of hepatocyte [aspartate aminotransferase (AST), international normalized ratio (INR), factor V, and caspase 3 immunohistochemistry], endothelial cell (EC; CD31 immunohistochemistry and hyaluronic acid), and biliary injury and function [alkaline phosphatase (ALP), total bilirubin, and bile lactate dehydrogenase (LDH)] were determined. Long‐term survival (7 days) after transplantation was similar between the SNEVLP and CS groups (60% versus 40%, P = 0.13). No difference was observed between SNEVLP‐ and CS‐treated animals with respect to the peak of serum INR, factor V, or AST levels within 24 hours. CD31 staining 8 hours after transplantation demonstrated intact EC lining in SNEVLP‐treated livers (7.3 × 10−4 ± 2.6 × 10−4 cells/μm2) but not in CS‐treated livers (3.7 × 10−4 ± 1.3 × 10−4 cells/μm2, P = 0.03). Posttransplant SNEVLP animals had decreased serum ALP and serum bilirubin levels in comparison with CS animals. In addition, LDH in bile fluid was lower in SNEVLP pigs versus CS pigs (14 ± 10 versus 60 ± 18 μmol/L, P = 0.02). Bile duct histology revealed severe bile duct necrosis in 3 of 5 animals in the CS group but none in the SNEVLP group (P = 0.03). Sequential SNEVLP preservation of DCD grafts reduces bile duct and EC injury after liver transplantation. Liver Transpl 20:1296‐1305, 2014.

Human Solid Tumor Xenografts in Immunodeficient Mice Are Vulnerable to Lymphomagenesis Associated with Epstein-Barr Virus

Xenografting primary human solid tumor tissue into immunodeficient mice is a widely used tool in studies of human cancer biology; however, care must be taken to prove that the tumors obtained recapitulate parent tissue. We xenografted primary human hepatocellular carcinoma (HCC) tumor fragments or bulk tumor cell suspensions into immunodeficient mice. We unexpectedly observed that 11 of 21 xenografts generated from 16 independent patient samples resembled lymphoid neoplasms rather than HCC. Immunohistochemistry and flow cytometry analyses revealed that the lymphoid neoplasms were comprised of cells expressing human CD45 and CD19/20, consistent with human B lymphocytes. In situ hybridization was strongly positive for Epstein-Barr virus (EBV) encoded RNA. Genomic analysis revealed unique monoclonal or oligoclonal immunoglobulin heavy chain gene rearrangements in each B-cell neoplasm. These data demonstrate that the lymphoid neoplasms were EBV-associated human B-cell lymphomas. Analogous to EBV-associated lymphoproliferative disorders in immunocompromised humans, the human lymphomas in these HCC xenografts likely developed from reactivation of latent EBV in intratumoral passenger B lymphocytes following their xenotransplantation into immunodeficient recipient mice. Given the high prevalence of latent EBV infection in humans and the universal presence of B lymphocytes in solid tumors, this potentially confounding process represents an important pitfall of human solid tumor xenografting. This phenomenon can be recognized and avoided by routine phenotyping of primary tumors and xenografts with human leukocyte markers, and provides a compelling biological rationale for exclusion of these cells from human solid tumor xenotransplantation assays.