A J d'Apice

St. Vincent's Hospital Melbourne, Melbourne, Victoria, Australia

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Publications (110)376.68 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Ischemia-reperfusion injury (IRI) is a major limiting event for successful liver transplantation, and CD4(+) T cells and invariant NKT (iNKT) cells have been implicated in promoting IRI. We hypothesized that hepatic over-expression of CD39, an ecto-nucleotidase with anti-inflammatory functions, will protect liver grafts after prolonged cold ischemia. CD39-transgenic (CD39tg) and wild type (WT) mouse livers were transplanted into WT recipients after 18 hours cold storage, and pathological analysis was performed 6 hours after transplantation. Serum levels of alanine aminotransferase and IL-6 were significantly reduced in recipients of CD39tg livers compared to recipients of WT livers. Furthermore, less severe histopathological injury was demonstrated in the CD39tg grafts. Immune analysis revealed that CD4(+) T cells and iNKT cells were significantly decreased in number in the livers of untreated CD39tg mice. This was associated with a peripheral CD4(+) T cell lymphopenia due to defective thymocyte maturation. To assess the relative importance of liver-resident CD4(+) T cells and iNKT cells in mediating liver injury following extended cold preservation and transplantation, WT mice depleted of CD4(+) T cells or mice genetically deficient in iNKT cells were used as donors. The absence of CD4(+) T cells, but not iNKT cells, protected liver grafts from early IRI. CONCLUSION: Hepatic CD4(+) T cells, but not iNKT cells, play a critical role in early IRI following extended cold preservation in a liver transplant model. (HEPATOLOGY 2012.).
    Hepatology 04/2013; 57(4). DOI:10.1002/hep.25985 · 11.19 Impact Factor
  • Xenotransplantation 11/2010; 17(6):411-2. DOI:10.1111/j.1399-3089.2010.00611.x · 1.78 Impact Factor
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    Peter J Cowan, Anthony Jf d'Apice
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    ABSTRACT: Xenotransplantation using porcine donors holds tremendous promise for alleviating the chronic shortage of human organ donors. However, transplantation from pigs into higher primates triggers a vigorous immune response involving complement activation and thrombosis. Hyperacute rejection can be prevented by using donors in which GalT, the gene responsible for the predominant target of anti-pig natural antibodies, has been deleted. Unfortunately, the adaptive response to GalT knockout (KO) organs has been difficult to immunosuppress. The focus has shifted to identifying additional genetic modifications that will extend xenograft survival beyond the several months currently achievable. Which gene(s) should be added to the GalT KO background is open to debate. Overexpression of a complement regulatory factor(s) seems a logical first choice, supported by recent in vitro data but not yet validated in preclinical models. The next obvious candidate would be an anticoagulant protein(s) to deal with the dysregulated coagulation that is almost invariably associated with xenograft rejection. Several potentially useful molecules have been identified, although this study is yet to be translated to the pig. Our understanding of the mechanisms of GalT KO xenograft rejection continues to grow, providing a rational basis for tailoring further genetic modification of the donor and immunosuppression of the recipient.
    Immunology and Cell Biology 02/2009; 87(3):203-8. DOI:10.1038/icb.2008.107 · 4.21 Impact Factor
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    Bryce JW DENDEREN, Martin J PEARSE, Anthony JF D'APICE
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    ABSTRACT: Xenotransplantation of non-human organs into human recipients has long been proposed as a possible strategy to overcome the acute shortage of donor organs. However, vascular organ transplants to humans from phylogenetically disparate species such as the pig are not currently possible due to a rapid rejection process termed hyperacute rejection. This process is initiated by the binding of host pre-formed ‘natural antibodies’ to the donor vascular endothelium, activation of the host complement system and activation or injury of the donor endothelial cells, leading to intravascular coagulation and loss of the graft due to ischaemic necrosis within minutes to hours of engraftment. Prevention of natural antibody binding and complement activation is viewed as paramount to preventing hyperacute rejection. Even if hyperacute rejection can be prevented, further barriers to successful discordant xenografts such as delayed xenograft rejection and a donor-directed cell-mediated rejection process will still represent major obstacles. This review examines recent advances being made in the various areas of xenograft research and the potential clinical application of pig-to-human xenografts that these strategies may bring.
    Nephrology 04/2007; 2(4):217 - 227. DOI:10.1111/j.1440-1797.1996.tb00091.x · 1.86 Impact Factor
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    ABSTRACT: T-cell apoptosis is an important regulatory mechanism in transplant tolerance. The aim of this study was to identify specific apoptotic molecules important for tolerance induction. Mice expressing the human Bcl-2 molecule in T cells or Bim -/- mice were used as islet allograft or rat islet xenograft recipients and treated with CTLA4-Fc and MR1 costimulation blockade. hBcl-2 transgenic mice and Bim -/- accepted islet allografts and rat islet xenografts for more than 100 days, similar to wildtype controls. Changes in the dose of the CTLA4-Fc and MR1 did not lead to differences in graft survival and there were no differences in the percentage of CD4+ T cells expressing Fas, CD25, or undergoing apoptosis. Inhibition of the passive cell death pathway in T cells did not block tolerance induction, suggesting that the mechanism by which apoptosis regulates the alloimmune response is more complex than first thought.
    Transplantation 04/2007; 83(5):653-5. DOI:10.1097/01.tp.0000255592.09784.ba · 3.78 Impact Factor
  • Peter J Cowan, Mark B Nottle, Anthony JF d'Apice
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    ABSTRACT: Purpose of review: The past year has seen several pig-to-baboon transplant studies using α1,3-galactosyltransferase-deficient donors. There are now sufficient data to begin to assess the impact of this important modification, and to review additional genetic strategies that may bring xenotransplantation to the clinic. Recent findings: Survival of pig heart and kidney xenografts can now be measured in months rather than weeks, and the introduction of α1,3-galactosyltransferase-deficient donors has removed the requirement for depletion of anti-galactose-α1,3-galactose antibodies. The main obstacle to even longer survival is the development of antibodies to as yet unidentified non-galactose-α1,3-galactose antigens. Analysis of rejected grafts indicates that these antibodies activate graft endothelium, and the resulting prothrombotic state is poorly controlled because endogenous porcine anticoagulants fail to efficiently regulate primate clotting factors. Manipulation of the donor or graft to express anticoagulant and immunosuppressive molecules has produced encouraging results in small animal models. It is conceivable that expression of these molecules in pigs, in combination with the existing α1,3-galactosyltransferase-deficient and complement regulator transgenic modifications, will result in stable long-term xenograft survival. Summary: The α1,3-galactosyltransferase-deficient pig has advanced the field and becomes the platform on which further genetic modifications are built.
    Current Opinion in Organ Transplantation 01/2007; 12(1):30-36. DOI:10.1097/MOT.0b013e328012b0bb · 2.38 Impact Factor
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    ABSTRACT: Purpose of review: The success of islet allotransplantation has highlighted the need for an alternative source of islet tissue. This review looks at the current status of islet xenotransplantation and what progress has been made towards a clinical therapy. Recent findings: There has been substantial progress in preclinical studies of islet xenotransplantation. Pig islets have been shown to control diabetes in rhesus macaques beyond 100 days using strong immunosuppression. There have been advances in our understanding of the fate of islets after transplantation. Exposure of pig islets to human blood leads to the instant blood-mediated inflammatory reaction, a likely cause of early graft loss. Islets surviving this reaction face immunological rejection by anti-pig antibodies and cell-mediated rejection. There has been progress with novel immunosuppressive approaches. The use of local immunosuppression secreted by the graft utilizes the therapeutic option of genetically altering the pig to enhance graft survival. Summary: Our understanding of issues such as instant blood-mediated inflammatory reaction and rejection have led to new strategies to overcome these problems. What is required now is well-planned preclinical studies to test these and to develop a protocol that is suitable to clinical application.
    Current Opinion in Organ Transplantation 03/2006; 11(2):174-179. DOI:10.1097/01.mot.0000218932.27397.19 · 2.38 Impact Factor
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    ABSTRACT: The search for alternative sources for transplant organs leads us to the search for animals as an inexhaustible source of organs. The objective of this study was to analyze whether livers from polytransgenic pigs expressing the human complement regulatory proteins CD55 (hDAF), CD59, and alfa alpha1,2-fucosyltransferase (H-transferase), protected against hyperacute rejection after orthotopic liver xenotransplantation to a baboon and also to study pig liver function in a nonhuman primate. Nine liver transplants from pig to baboon were divided into two groups: a control group (n = 4) of genetically unmodified pigs and an experimental group (n = 5) of pigs transgenic for CD55, CD59, and H-transferase as donors. All the donating piglets obtained through hysterectomy were maintained in specific pathogen-free conditions. The selection of transgenic pig donors followed demonstration of transgene expression using monoclonal antibodies (antiCD55, antiCD59) and immunohistological studies on liver biopsies. All animals in the control group developed hyperacute rejection with survival rates less than 16 hours without function of transplanted livers. In the experimental group none of the animals suffered hyperacute rejection. Survival in this group was between 13 and 24 hours. The livers were functional, producing bile and maintaining above 35% prothrombin activity. Only in one case was there primary dysfunction of the xenograft. Polytransgenic livers for complement regulatory proteins prevent hyperacute rejection when xenotransplanted into a baboon.
    Transplantation Proceedings 12/2005; 37(9):4103-6. DOI:10.1016/j.transproceed.2005.09.186 · 0.95 Impact Factor
  • Nephrology 02/2002; 7(1). DOI:10.1046/j.1440-1797.2002.00007-1-59.x · 1.86 Impact Factor
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    ABSTRACT: A retrospective analysis of transgenesis rates obtained in seven pronuclear microinjection programs was undertaken to determine if a relationship existed between the amount of DNA injected and transgenesis rates in the pig. Logistic regression analysis showed that as the concentration of DNA injected increased from 1 to 10 ng/microl, the number of transgenics when expressed as a proportion of the number liveborn (integration rate) increased from 4% to an average of 26%. A similar relationship was found when the number of molecules of DNA injected per picolitre was analysed. No evidence was obtained to suggest either parameter influenced integration rate in mice when the same constructs were injected. The number of transgenics liveborn when expressed as a proportion of ova injected (efficiency rate), increased as DNA concentration increased up to 7.5 ng/microl and then decreased at 10 ng/microl for both species suggesting that at this concentration DNA (or possible contaminants) may have influenced embryo survival. The relationship between efficiency and the number of molecules injected per picolitre was complex suggesting that the concentration at which DNA was injected was a better determinant of integration and efficiency rates. In conclusion, the present study suggests that transgenes need to be injected at concentrations of between 5 and 10 ng/microl to maximise integration and efficiency rates in pigs.
    Transgenic Research 01/2002; 10(6):523-31. DOI:10.1023/A:1013007329936 · 2.28 Impact Factor
  • A J d'Apice, M B Nottle, P J Cowan
    Transplantation Proceedings 11/2001; 33(7-8):3053-4. DOI:10.1016/S0041-1345(01)02305-3 · 0.95 Impact Factor
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    ABSTRACT: The involvement of the vascular endothelium in a large number of diseases supports the importance of vascular-specific gene delivery for their treatment. The hereditary hemorrhagic telangiectasia type 1 is an example of a vascular inherited disease (OMIM 187300). This is an autosomal dominant vascular disorder originated by mutations in the endoglin gene and associated with frequent epistaxis, telangiectases, gastrointestinal bleedings, and arteriovenous malformations in brain, lung and liver. Here, we address for the first time the possibility of using in vivo gene transfer to target endoglin expression to the vasculature. The promoter of the endothelial gene, ICAM-2, was used to generate transgenic animals which demonstrated endothelial expression of endoglin. Next, the promoters of the human endothelial genes, endoglin and ICAM-2, were inserted upstream of the human endoglin cDNA, and the resulting constructs were systemically or locally delivered, demonstrating endoglin expression in the vessel walls of liver, lung and skin. These gene transfer experiments represent an initial step in the treatment of the hereditary hemorrhagic telangiectasia type 1 by gene therapy, and suggest that endoglin and ICAM-2 promoters can be used to deliver other genes to the endothelium specifically.
    Gene Therapy 07/2001; 8(12):897-904. DOI:10.1038/sj.gt.3301468 · 4.20 Impact Factor
  • A J D'Apice, P J Cowan
    Transplantation 12/2000; 70(9):1273-4. DOI:10.1097/00007890-200011150-00003 · 3.78 Impact Factor
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    Transplantation Proceedings 12/2000; 32(7):2075. DOI:10.1016/S0041-1345(00)01574-8 · 0.95 Impact Factor
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    ABSTRACT: Pig-to-primate vascularized xenografts undergo hyperacute rejection (HAR). This results from pre-formed xenoreactive antibodies directed against galactose-alpha1,3-galactose (alphaGal) in the donor organ and activation of the complement cascade. We describe an in vivo murine model of HAR using a BALB/c mice system devoid of histocompatibility or complement differences between donor and recipient to investigate in isolation, the effects of alphaGal epitope and anti-alphaGal antibody interactions in causing rejection of vascularized heart transplants. Gal KO mice were immunized with rabbit red blood cell membranes to induce high anti-alphaGal antibody titers that were predominantly IgM by ELISA (enzyme-linked immunosorbent assay). When alphaGal-expressing mice hearts were transplanted heterotopically into these recipients (n= 12), 67% of grafts rejected within 24 h, the majority within 16 h with histological features of HAR. In contrast, none of the grafts in the non-immunized Gal KO recipient control group (n=11) underwent HAR. Interestingly, approximately 50% of the remaining grafts in both the immunized and non-immunized Gal KO recipient group were rejected between 7 and 27 days by a rejection process characterized by a dense infiltrate of macrophage/monocytes, perivascular cuffing and tissue destruction similar to recent descriptions of delayed xenograft rejection (DXR). In addition, some grafts (21.5%) continued to survive in the immunized Gal KO recipients despite the presence of anti-alphaGal antibody and normal complement activity and these showed well-preserved myocardium when harvested whilst still functioning well at days 30 or 90. No rejection was seen when Gal KO donors were used in this system (n=4), nor when alphaGal-expressing BALB/c hearts were transplanted into alphaGal-expressing BALB/c recipients (n=5). This in vivo small animal model offers the opportunity to test a variety of strategies to overcome HAR prior to more resource intensive pig-to-primate studies, and may provide insights into the processes similar to DXR and accommodation.
    Xenotransplantation 12/2000; 7(4):237-46. · 1.78 Impact Factor
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    ABSTRACT: It has been proposed that hyperacute rejection (HAR) of pig-to-primate vascularized xenografts is due in large part to ineffective regulation of recipient complement by pig complement regulatory proteins (CRPs), and indeed transgenic expression of human CRPs in pigs can prevent hyperacute rejection. However, at least one pig CRP (CD59) efficiently regulates human complement in vitro, suggesting that it is the level of expression of a particular CRP(s) rather than cross-species incompatibility that explains the HAR of porcine xenografts. We investigated the relative effectiveness of transgenically expressed pig and human CD59 in providing protection of mouse hearts from human complement in an ex vivo setting. Transgenic mice expressing pig CD59 or human CD59 under the control of the human ICAM-2 promoter, which restricts expression in tissues to vascular endothelium, were used. Hearts from mice expressing similar levels of pig CD59 or human CD59 were perfused ex vivo with 10% human plasma and heart function was monitored for 60 min. Sections of perfused hearts were examined for deposition of the membrane attack complex (MAC). Control nontransgenic hearts (n=5) were rapidly affected by the addition of human plasma, with mean function falling to less than 10% of the initial level within 15 min. In contrast, hearts expressing either pig CD59 (n=6) or human CD59 (n=8) were protected from plasma-induced injury, maintaining 31 and 35% function, respectively, after 60 min of perfusion. MAC deposition was markedly reduced in both pig CD59 and human CD59 transgenic hearts compared to nontransgenic control hearts. When highly expressed on endothelium in transgenic mice, pig CD59 provided equivalent protection to human CD59 in a model of human complement-mediated xenograft rejection. Thus supranormal expression of endogenous porcine CRPs may be a feasible alternative to the expression of human CRPs in preventing HAR of pig-to-primate xenografts.
    Transplantation 10/2000; 70(6):963-8. DOI:10.1097/00007890-200009270-00014 · 3.78 Impact Factor
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    ABSTRACT: Acute vascular xenograft rejection (AVXR), also termed delayed xenograft rejection (DXR), occurs when hyperacute rejection (HAR) is prevented by strategies directed at xenoreactive natural antibodies and/or complement activation. We have hypothesized that AVXR/DXR is initiated in part by early components of the complement cascade, notably C1q. We have developed synthetic peptides (termed CBP2 and WY) that interfere with the interaction between C1q and antibody. CBP2 and the WY-conjugates were used as inhibitors of immunoglobulin aggregate binding to solid phase C1q. Inhibition of complement activation by the peptides of the classical system was determined using lysis assays with sensitized sheep red blood cells or porcine aortic endothelial cells as targets and of the alternate complement pathway using guinea pig red blood cells as targets. Two transplant models were used to study the effects of administering peptides to recipients: rat heart transplant to presensitized mouse, and guinea heart transplant to PVG C6-deficient rats. CBP2 and WY-conjugates inhibited immunoglobulin aggregate binding to C1q. The peptides also inhibited human complement-mediated lysis of sensitized sheep red blood cells and porcine aortic endothelial cells in a dose-dependent manner and the WY-conjugates prevented activation of the alternate complement pathway as shown by inhibition of guinea pig red blood cells lysis with human serum. In addition, the use of the peptides and conjugates resulted in significant prolongation of xenograft survival. The CBP2 and WY peptides exhibit the functional activity of inhibition of complement activation. These peptides also prolong xenograft survival and thus provide reagents for the study of the importance of C1q and other complement components in transplant rejection mechanisms.
    Transplantation 10/2000; 70(5):828-36. DOI:10.1097/00007890-200009150-00021 · 3.78 Impact Factor
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    ABSTRACT: The genetic modification of pigs is a powerful strategy that may ultimately enable successful xenotransplantation of porcine organs into humans. Transgenic pigs were produced by microinjection of gene constructs for human complement regulatory proteins CD55 and CD59 and the enzyme alpha1,2-fucosyltransferase (H-transferase, HT), which reduces expression of the major xenoepitope galactose-alpha1,3-galactose (alphaGal). Kidneys from CD55/HT and CD55/CD59/HT transgenic pigs were transplanted into nephrectomised, nonimmunosuppressed adult baboons. In several lines of transgenic pigs, CD55 and CD59 were expressed strongly in all tissues examined, whereas HT expression was relatively weak and did not significantly reduce alphaGal. Control nontransgenic kidneys (n=4) grafted into baboons were hyperacutely rejected within 1 hr. In contrast, kidneys from CD55/HT pigs (n=2) were rejected after 30 hr, although kidneys from CD55/CD59/HT pigs (n=6) maintained function for up to 5 days. In the latter grafts, infiltration by macrophages, T cells, and B cells was observed at days 3 and 5 posttransplantation. The recipients developed thrombocytopenia and abnormalities in coagulation, manifested in increased clotting times and an elevation in the plasma level of the fibrin degradation product D-dimer, within 2 days of transplantation. Treatment with low molecular weight heparin prevented profound thrombocytopenia but not the other aspects of coagulopathy. Strong expression of CD55 and CD59 completely protected porcine kidneys from hyperacute rejection and allowed a detailed analysis of xenograft rejection in the absence of immunosuppression. Coagulopathy appears to be a common feature of pig-to-baboon renal transplantation and represents yet another major barrier to its clinical application.
    Transplantation 07/2000; 69(12):2504-15. DOI:10.1097/00007890-200006270-00008 · 3.78 Impact Factor
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    ABSTRACT: Antibodies directed against galactose-alpha1,3-galactose (alphaGal) are believed to play an important role in the pathogenesis of delayed xenograft rejection (DXR). This study was designed to determine whether alpha1,3-galactosyltransferase-deficient (Gal KO) mice can naturally acquire a sufficient anti-alphaGal titre to cause the delayed type rejection of alphaGal-expressing hearts. Gal KO mice of various ages were assessed for anti-alphaGal antibody levels. alphaGal-expressing hearts were transplanted heterotopically into these mice and monitored daily. Rejecting and surviving hearts were evaluated histologically. In Gal KO mice greater than 6-month-old, 64% had an anti-alphaGal antibody titre above the background level. When wild-type alphaGal-expressing hearts were transplanted into this group, 45% of grafts rejected within 5 to 13 days. Histological examination of the rejected hearts displayed marked tissue damage and an inflammatory infiltrate of predominantly macrophage/monocytes. Surviving grafts showed preserved morphology. Like humans, Gal KO mice naturally develop anti-alphaGal antibodies with age. The titre in these mice was sufficient to cause a "delayed-type" rejection of a significant proportion of alphaGal-expressing cardiac grafts. This model thus provides an opportunity to investigate the role of naturally acquired anti-alphaGal antibodies in the pathogenesis of DXR.
    Xenotransplantation 03/2000; 7(1):42-7. · 1.78 Impact Factor
  • D J Goodman, A J d'Apice
    Transplantation 12/1999; 68(11):1630-1. DOI:10.1097/00007890-199912150-00004 · 3.78 Impact Factor

Publication Stats

2k Citations
376.68 Total Impact Points

Institutions

  • 1989–2013
    • St. Vincent's Hospital Melbourne
      • Immunology Research Centre
      Melbourne, Victoria, Australia
    • The Royal Children's Hospital
      Melbourne, Victoria, Australia
    • Oregon Health and Science University
      • Department of Medicine
      Portland, OR, United States
  • 1991–2007
    • St. Vincent Hospital
      Green Bay, Wisconsin, United States
  • 1987–1998
    • University of Melbourne
      • Department of Surgery
      Melbourne, Victoria, Australia
  • 1993
    • Royal Victorian Eye and Ear Hospital
      Melbourne, Victoria, Australia
  • 1980–1991
    • Royal Melbourne Hospital
      • Department of Nephrology
      Melbourne, Victoria, Australia