Clinical trials and projected future of liver xenotransplantation.

The trial and error of the pioneering xenotransplant trials over the past three decades has defined the limitation of the species used. Success was tantalizingly close with the chimpanzee, baboon, and other primates. The use of more disparate species has been frustrated by the xenoantibody barrier.

Hepatic resection and transplantation for peripheral cholangiocarcinoma.

Background: Recent publications have questioned the role of orthotopic liver transplantation (OLT) in treating advanced or unresectable peripheral cholangiocarcinoma (Ch-Ca).

Study Design: We reviewed our experience with Ch-Ca to determine survival rates, recurrence patterns, and risk factors in 54 patients who underwent either hepatic resection or OLT between 1981 and 1994. Liver transplantation was performed in patients with unresectable tumors (n = 12) and in those with advanced cirrhosis (n = 8).

HLA and cross-reactive antigen group matching for cadaver kidney allocation.

Background: Allocation of cadaver kidneys by graded human leukocyte antigen (HLA) compatibility scoring arguably has had little effect on overall survival while prejudicing the transplant candidacy of African-American and other hard to match populations. Consequently, matching has been proposed of deduced amino acid residues of the individual HLA molecules shared by cross-reactive antigen groups (CREGs). We have examined the circumstances under which compatibility with either method impacted graft survival.

Attenuation of ischemic liver injury by monoclonal anti-endothelin antibody, AwETN40.

Background: Enhanced production of endothelin-1 (ET-1), vasoconstrictive 21 amino acids produced by endothelial cells during ischemia and after reperfusion of the liver, is known to cause sinusoidal constriction and microcirculatory disturbances, which lead to severe tissue damage. Using a 2-hour hepatic vascular exclusion model in dogs, we tested our hypothesis that neutralization of ET-1 by monoclonal anti-ET-1 and anti-ET-2 antibody (AwETN40) abates vascular dysfunction and ameliorates ischemia/reperfusion injury of the liver.

Study Design: After skeletonization, the liver was made totally ischemic by cross-clamping the portal vein, the hepatic artery, and the vena cava (above and below the liver).

Correction of congenital hyperbilirubinemia in homozygous Gunn rats by xenotransplantation of hamster livers.

The homozygous Gunn(j/j) rat is an animal model for Crigler-Najjarsyndrome in which the lack of the enzyme uridine diphosphoglucoronate-glucuronosyltransferase (UDP-GT) results in congenital unconjugated nonhemolytic hyperbilirubinemia. Because the binding of bilirubin to albumin in plasma varies from species to species, xenotransplantation (XTx) of liver afforded in this model the opportunity to study the interactions between xenoproteins of the donor and bilirubin of the recipient. For this purpose, orthotopic liver transplantation (OLTx) was performed from hamster to adult Gunn(j/j) rats.

Treatment of fibrolamellar hepatoma with subtotal hepatectomy or transplantation.

Fibrolamellar hepatoma (FL-HCC) is an uncommon variant of hepatocellular carcinoma (HCC), distinguished by histopathological features suggesting greater differentiation than conventional HCC. However, the optimal treatment and the prognosis of FL-HCC have been controversial. Follow-up studies are available from 1 year to 27 years, after 41 patients with FL-HCC were treated with partial hepatectomy (PHx) (28 patients) or liver transplantation (13 patients).

Evidence for the presence of multilineage chimerism and progenitors of donor dendritic cells in the peripheral blood of bone marrow-augmented organ transplant recipients.

We have postulated that the donor leukocyte microchimerism plays a seminal role in the acceptance of allografts by inducing and perpetuating variable degree of donor-specific nonreactivity in long-surviving organ recipients. Limited information is available, however, concerning the phenotype and function of these chimeric cells in humans. The unequivocal presence of donor dendritic cells (DCs), a prominent lineage in the microchimerism observed in rodents and clinical organ recipients, was difficult to demonstrate in bone marrow (BM)-augmented organ transplant recipients.

Abrogation of chronic rejection in a murine model of aortic allotransplantation by prior induction of donor-specific tolerance.

Aortic allotransplantation in mice has been well established as a model of choice to study the evolvement of chronic rejection, the etiopathology of which is believed to be that of immune origin. This has prompted the postulation that prior induction of donor-specific tolerance would attenuate or abrogate the underlying events that culminate in posttransplant arteriosclerosis. To study the effects of donor-specific tolerance on chronic rejection, we performed orthotopic liver transplantation without immunosuppression in mice 30 days before aortic allotransplantation across C57Bl/ 10J (H2b)-->C3H (H2k) strain combinations (group III).

On the crossroad between tolerance and posttransplant lymphoma.

The role of the Epstein-Barr virus in the development of post-transplant lymphomas is well established. However, not all lymphomas that arise in these patients contain Epstein-Barr virus, suggesting that other cofactors are involved in tumor pathogenesis. We propose that immunologic interactions that result from the introduction of immunocompetent donor cells during transplantation contribute to a lymphomagenic environment in the host.

Pregnancy after liver transplantation under tacrolimus.

Background: The maternal and fetal risk of pregnancy after organ transplantation under tacrolimus has not been reported. This was prospectively studied in 27 pregnancies by 21 female liver recipients who were treated with tacrolimus before and throughout gestation.

Method: Twenty-seven babies were born between October 1990 and April 1996.

Hepatitis C virus genotypes in liver transplant recipients: impact on posttransplant recurrence, infections, response to interferon-alpha therapy and outcome.

Background: End-stage liver disease due to hepatitis C virus (HCV) is the most common indication for liver transplantation in U.S. veterans.

Adult heart transplantation under tacrolimus (FK506) immunosuppression: histopathologic observations and comparison to a cyclosporine-based regimen with lympholytic (ATG) induction.

Background: Tacrolimus (FK506) is an effective immunosuppressant for human heart transplantation, but information about its effects on cardiac allograft and nonallograft kidney and liver histopathologic study is limited.

Methods: We therefore reviewed 1145 endomyocardial biopsy specimens and eight autopsy results from 80 heart transplant recipients who received tacrolimus as baseline immunosuppression. These were compared with 619 endomyocardial biopsy specimens and four autopsy results from 51 patients treated with cyclosporine-based immunosuppression with lympholytic induction (CLI) by use of rabbit anti-thymocyte globulin.

Effect in supralethally irradiated rats of granulocyte colony-stimulating factor and lisofylline on hematopoietic reconstitution by syngeneic bone marrow or whole organ passenger leukocytes.

We have previously shown the existence of migratory hematopoietic stem cells in adult solid organs. This study demonstrates that granulocyte colony-stimulating factor (G-CSF) and lisofylline, a phosphatidic acid inhibitor that suppresses hematopoiesis-inhibiting cytokines, can enhance the engraftment of organ-based hematopoietic stem cells. When syngeneic heart grafts or liver nonparenchymal cells were transplanted into lethally irradiated (9.

Clinical features of acute reversible tacrolimus (FK 506) nephrotoxicity in kidney transplant recipients.

This study was designed to (a) estimate the contribution of tacrolimus nephrotoxicity to episodes of renal allograft dysfunction investigated by needle biopsy, (b) describe the temporal evolution of nephrotoxicity and its response to therapy, and (c) ascertain how often renal dysfunction is associated with concurrent extra-renal toxicity. Patients were selected based on a rising serum creatinine, normal ultrasound, and biopsy findings leading to a reduction in the dose of tacrolimus and a fall in serum creatinine. Twenty two (17%) cases of nephrotoxicity were identified amongst 128 consecutive kidney transplant biopsies with sufficient clinical data for analysis.

Autologous lymphokine-activated killer cell therapy of Epstein-Barr virus-positive and -negative lymphoproliferative disorders arising in organ transplant recipients.

Lymphoreticular malignancies, collectively called posttransplant lymphoproliferative disorders (PTLD), eventually develop in 2-5% of organ transplant recipients. They frequently undergo regression when immunosuppression is reduced or stopped. This feature has been associated with a previous or de novo Epstein-Barr virus (EBV) infection.

Striking augmentation of hematopoietic cell chimerism in noncytoablated allogeneic bone marrow recipients by FLT3 ligand and tacrolimus.

The influence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and the recently identified hematopoietic stem-progenitor cell mobilizing factor flt3 ligand (FL) on donor leukocyte microchimerism in noncytodepleted recipients of allogeneic bone marrow (BM) was compared. B10 mice (H2b) given 50x10(6) allogeneic (B10.BR [H2k]) BM cells also received either GM-CSF (4 microg/day s.

Apoptosis within spontaneously accepted mouse liver allografts: evidence for deletion of cytotoxic T cells and implications for tolerance induction.

MHC-mismatched liver grafts are accepted spontaneously between many mouse strains. The underlying mechanism(s) is unclear. In the B10 (H2(b)) to C3H (H2(k)) strain combination used in this study, donor T cells within the liver were rapidly replaced within 2 to 4 days of transplantation with those of the recipient.

Crystallization and preliminary crystallographic data for the augmenter of liver regeneration.

A new cellular growth factor termed augmenter of liver regeneration (ALR) has been crystallized. ALR has been shown to have a proliferative effect on liver cells while at the same time producing an immunosuppressive effect on liver-resident natural killer cells and liver-resident mononuclear leukocytes. In addition, ALR appears to play an important role in the synthesis and stabilization of mitochondrial gene transcripts in actively regenerating cells.

Chimerism after organ transplantation.

Recent evidence suggests that passenger leukocytes migrate after organ transplantation and produce persistent chimerism, which is essential for sustained survival of the allograft. Here, we describe how this hematolymphopoietic chimerism provides an important framework for interpretation of post-transplant phenomena and for initiation of therapeutically oriented transplantation research.