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O'Neill NA, Zhang T, Braileanu G, Sun W, Cheng X, Hershfeld A, Laird CT, Kronfli A, Hock LA, Dahi S, Kubicki N, Sievert E, Hassanein W, Cimeno A, Pierson RN, Azimzadeh AM. Comparative Evaluation of αCD40 (2C10R4) and αCD154 (5C8H1 and IDEC-131) in a Nonhuman Primate Cardiac Allotransplant Model. Transplantation 2017; 101:2038-2047. [PMID: 28557955 PMCID: PMC5568940 DOI: 10.1097/tp.0000000000001836] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Specific blockade of T cell costimulation pathway is a promising immunomodulatory approach being developed to replace our current clinical immunosuppression therapies. The goal of this study is to compare results associated with 3 monoclonal antibodies directed against the CD40/CD154 T cell costimulation pathway. METHODS Cynomolgus monkey heterotopic cardiac allograft recipients were treated with either IDEC-131 (humanized αCD154, n = 9), 5C8H1 (mouse-human chimeric αCD154, n = 5), or 2C10R4 (mouse-rhesus chimeric αCD40, n = 6) monotherapy using a consistent, comparable dosing regimen for 3 months after transplant. RESULTS Relative to the previously reported IDEC-131-treated allografts, median survival time (35 ± 31 days) was significantly prolonged in both 5C8H1-treated (142 ± 26, P < 0.002) and 2C10R4-treated (124 ± 37, P < 0.020) allografts. IDEC-131-treated grafts had higher cardiac allograft vasculopathy severity scores during treatment relative to either 5C8H1 (P = 0.008) or 2C10R4 (P = 0.0002). Both 5C8H1 (5 of 5 animals, P = 0.02) and 2C10R4 (6/6, P = 0.007), but not IDEC-131 (2/9), completely attenuated IgM antidonor alloantibody (alloAb) production during treatment; 5C8H1 (5/5) more consistently attenuated IgG alloAb production compared to 2C10R4 (4/6) and IDEC-131 (0/9). All evaluable explanted grafts experienced antibody-mediated rejection. Only 2C10R4-treated animals exhibited a modest, transient drop in CD20 lymphocytes from baseline at day 14 after transplant (-457 ± 152 cells/μL) compared with 5C8H1-treated animals (16 ± 25, P = 0.037), and the resurgent B cells were primarily of a naive phenotype. CONCLUSIONS In this model, CD154/CD40 axis blockade using IDEC-131 is an inferior immunomodulatory treatment than 5C8H1 or 2C10R4, which have similar efficacy to prolong graft survival and to delay cardiac allograft vasculopathy development and antidonor alloAb production during treatment.
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Cooper DK, Pierson RN, Hering BJ, Mohiuddin MM, Fishman JA, Denner J, Ahn C, Azimzadeh AM, Buhler LH, Cowan PJ, Hawthorne WJ, Kobayashi T, Sachs DH. Regulation of Clinical Xenotransplantation-Time for a Reappraisal. Transplantation 2017; 101:1766-1769. [PMID: 28737658 PMCID: PMC5702547 DOI: 10.1097/tp.0000000000001683] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The continual critical shortage of organs and cells from deceased human donors has stimulated research in the field of cross-species transplantation (xenotransplantation), with the pig selected as the most suitable potential source of organs. Since the US Food and Drug Administration concluded a comprehensive review of xenotransplantation in 2003, considerable progress has been made in the experimental laboratory to improve cell and organ xenograft survival in several pig-to-nonhuman primate systems that offer the best available models to predict clinical outcomes. Survival of heart, kidney, and islet grafts in nonhuman primates is now being measured in months or even years. The potential risks associated with xenotransplantation, for example, the transfer of an infectious microorganism, that were highlighted in the 2003 Food and Drug Administration guidance and subsequent World Health Organization consensus documents have been carefully studied and shown to be either less likely than previously thought or readily manageable by donor selection or recipient management strategies. In this context, we suggest that the national regulatory authorities worldwide should re-examine their guidelines and regulations regarding xenotransplantation, so as to better enable design and conduct of safe and informative clinical trials of cell and organ xenotransplantation when and as supported by the preclinical data. We identify specific topics that we suggest require reconsideration.
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Cooper DK, Wijkstrom M, Hariharan S, Chan JL, Singh A, Horvath K, Mohiuddin M, Cimeno A, Barth RN, LaMattina JC, Pierson RN. Selection of Patients for Initial Clinical Trials of Solid Organ Xenotransplantation. Transplantation 2017; 101:1551-1558. [PMID: 27906824 PMCID: PMC5453852 DOI: 10.1097/tp.0000000000001582] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Several groups have reported extended survival of genetically engineered pig organs in nonhuman primates, varying from almost 10 months for life-supporting kidney grafts and more than 2 years for non-life-supporting heart grafts to less than 1 month for life-supporting liver and lung grafts. We have attempted to define groups of patients who may not have an option to wait for an allograft. These include kidney, heart, and lung candidates who are highly-allosensitized. In addition, some kidney candidates (who have previously lost at least 2 allografts from rapid recurrence of native kidney disease) have a high risk of further recurrence and will not be offered a repeat allotransplant. Patients with complex congenital heart disease, who may have undergone previous palliative surgical procedures, may be unsuitable for ventricular assist device implantation. Patients dying of fulminant hepatic failure, for whom no alternative therapy is available, may be candidates for a pig liver, even if only as a bridge until an allograft becomes available. When the results of pig organ xenotransplantation in nonhuman primates suggest a realistic potential for success of a pilot clinical trial, highly selected patients should be offered participation.
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Loeb KL, Radnitz C, Keller K, Schwartz MB, Marcus S, Pierson RN, Shannon M, DeLaurentis D. The application of defaults to optimize parents' health-based choices for children. Appetite 2017; 113:368-375. [DOI: 10.1016/j.appet.2017.02.039] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/31/2017] [Accepted: 02/27/2017] [Indexed: 12/20/2022]
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French B, Harris D, Laird C, Burdorf L, Cheng X, Feng C, Cross AS, Goldblum SE, Vasta GR, Pierson RN, Azimzadeh AM. Sialic acid and Galectins mediate Xenogenic Neutrophil-Endothelial Adhesion. THE JOURNAL OF IMMUNOLOGY 2017. [DOI: 10.4049/jimmunol.198.supp.82.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Sialic acids (Sias) play multifarious roles in immunity, and likely contribute to inflammation seen in xenograft failure. The ‘net’ cellular sialyation state depends on many things including transient loss of Sia moieties with exposure of subterminal galactosyl structures (mediated by sialyltransferases and sialidases [neuraminidases]), which can function as receptors for extracellular lectins, such as galectins. Here, we report the role of Sias in modulating adhesion of human neutrophils (NΦ’s) to pig endothelial cells.
Human (hAECs) and pig (pAECs) aortic endothelial cells were pretreated with Clostridium perfringens neuraminidase (NA, to remove Sias), human tumor necrosis factor (hTNF, 25 ug/ml), or both. CalceinAM-labelled human NΦ’s were treated with rhIL-8, NA, or N-acetyllactosamine (LacNAc, a galectin inhibitor). NΦ adhesion was measured and expressed as percent adhesion.
NA treatment of AECs increased NΦ adhesion to pig (36.3% vs 22.4%) more than to human (24.2% vs 20.7%) AECs. NΦ adhesion was similarly increased by TNF activation of AECs in static and flow conditions. hIL-8 dramatically increased NΦ adhesion to pAECs (76.5%, p<.001) and hAECs (45.3%, p<.001), with the highest adhesion observed with NA-treated pAECs and hIL-8-activated NΦ’s. Pre-exposure of the NΦ’s to LacNAc prevented their galectin-mediated adhesion to galactose moieties exposed on the NA-treated pAECs (13.7%, p<.0001).
In summary, AEC de-sialylation promotes xenogenic NΦ adhesion, an effect completely inhibited by pre-incubation of Nf’s with LacNAc. These results suggest the inhibition of sialidase activity or galectin binding as promising therapeutic approaches to limit inflammation in xenogeneic organ injury.
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Laird CT, Burdorf L, French BM, Kubicki N, Cheng X, Braileanu G, Sun W, O'Neill NA, Cimeno A, Parsell D, So E, Bähr A, Klymiuk N, Phelps CJ, Ayares D, Azimzadeh AM, Pierson RN. Transgenic expression of human leukocyte antigen-E attenuates GalKO.hCD46 porcine lung xenograft injury. Xenotransplantation 2017; 24. [DOI: 10.1111/xen.12294] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/04/2016] [Accepted: 01/26/2017] [Indexed: 02/06/2023]
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Rybak ER, Shipley S, Tatarov I, Zhang T, Sun W, Braileanu G, Burdorf L, Sievert E, Azimzadeh AM, DeTolla LJ, Pierson RN. Clinical Trypanosoma cruzi Disease after Cardiac Transplantation in a Cynomolgus Macaque ( Macaca fascicularis). Comp Med 2016; 66:494-498. [PMID: 28304254 PMCID: PMC5157966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/15/2016] [Accepted: 05/26/2016] [Indexed: 06/06/2023]
Abstract
A cynomolgus macaque received a heterotopic cardiac allograft as part of a transplant study, with monoclonal antibodies targeted to specific immune costimulation molecules (CD154, CD28) but no traditional immunosuppressive therapy after surgery. Clinical anemia was detected on postoperative day (POD) 35 and had worsened (Hgb, 2.3 g/dL; Hct = 7.3%) by POD 47, despite type-matched whole-blood transfusions. After a total of 4 blood transfusions, hematologic parameters were improved (Hgb, 5.9 g/dL; Hct, 18.7%). On POD 50, a peripheral blood smear revealed trypomastigotes, and qualitative RT-PCR of whole blood identified the organism as Trypanosoma cruzi. Although clinically stable initially, the macaque soon developed sufficient weight loss to necessitate euthanasia on POD 64. The final diagnosis was clinical anemia due to T. cruzi infection. This study represents the first reported case of Chagas disease after heart transplant in a NHP.
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O'Neill NA, Zhang T, Sun W, Braileanu G, Tatarov I, Hassanein W, Sendil S, Parsell DM, Pierson RN, Azimzadeh AM. Allograft Rejection with αCD28 and αB7 Costimulation Blockade Is Not Correlated with CD28- Graft Infiltrating T Lymphocytes. J Am Coll Surg 2016. [DOI: 10.1016/j.jamcollsurg.2016.06.312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Burdorf L, Riner A, Rybak E, Salles II, De Meyer SF, Shah A, Quinn KJ, Harris D, Zhang T, Parsell D, Ali F, Schwartz E, Kang E, Cheng X, Sievert E, Zhao Y, Braileanu G, Phelps CJ, Ayares DL, Deckmyn H, Pierson RN, Azimzadeh AM, Dandro A, Karavi K. Platelet sequestration and activation during GalTKO.hCD46 pig lung perfusion by human blood is primarily mediated by GPIb, GPIIb/IIIa, and von Willebrand Factor. Xenotransplantation 2016; 23:222-236. [PMID: 27188532 DOI: 10.1111/xen.12236] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 03/17/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND Here, we ask whether platelet GPIb and GPIIb/IIIa receptors modulate platelet sequestration and activation during GalTKO.hCD46 pig lung xenograft perfusion. METHODS GalTKO.hCD46 transgenic pig lungs were perfused with heparinized fresh human blood. Results from perfusions in which αGPIb Fab (6B4, 10 mg/l blood, n = 6), αGPIIb/IIIa Fab (ReoPro, 3.5 mg/l blood, n = 6), or both drugs (n = 4) were administered to the perfusate were compared to two additional groups in which the donor pig received 1-desamino-8-d-arginine vasopressin (DDAVP), 3 μg/kg (to pre-deplete von Willebrand Factor (pVWF), the main GPIb ligand), with or without αGPIb (n = 6 each). RESULTS Platelet sequestration was significantly delayed in αGPIb, αGPIb+DDAVP, and αGPIb+αGPIIb/IIIa groups. Median lung "survival" was significantly longer (>240 vs. 162 min reference, p = 0.016), and platelet activation (as CD62P and βTG) were significantly inhibited, when pigs were pre-treated with DDAVP, with or without αGPIb Fab treatment. Pulmonary vascular resistance rise was not significantly attenuated in any group, and was associated with residual thromboxane and histamine elaboration. CONCLUSIONS The GPIb-VWF and GPIIb/IIIa axes play important roles in platelet sequestration and coagulation cascade activation during GalTKO.hCD46 lung xenograft injury. GPIb blockade significantly reduces platelet activation and delays platelet sequestration in this xenolung rejection model, an effect amplified by adding αGPIIb/IIIa blockade or depletion of VWF from pig lung.
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Widen EM, Factor-Litvak PR, Gallagher D, Paxton A, Pierson RN, Heymsfield SB, Lederman SA. The Pattern of Gestational Weight Gain is Associated with Changes in Maternal Body Composition and Neonatal Size. Matern Child Health J 2016; 19:2286-94. [PMID: 26179720 DOI: 10.1007/s10995-015-1747-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES The pattern of gestational weight gain (GWG) reflects general nutrient availability to support growing fetal and maternal compartments and may contribute to later health, but how it relates to changes in maternal body composition is unknown. We evaluated how the pattern of GWG related to changes in maternal body composition during pregnancy and infant size at birth. METHODS A prospective, multi-ethnic cohort of 156 pregnant women and their infants was studied in New York City. Prenatal weights were used to estimate total and rate (kg/week) of GWG by trimester. Linear regression models evaluated the association between trimester-specific GWG group (low, medium, high GWG) [total (low ≤25, high ≥75 percentile) or rate (defined by tertiles)] and infant weight, length and maternal body composition changes from 14 to 37 weeks, adjusting for covariates. RESULTS Compared to the low gain group, medium/high rate of GWG in the second trimester and high rate of GWG in the third trimester were associated with larger gains in maternal fat mass (β range for fat Δ = 2.86-5.29 kg, all p < 0.01). For infant outcomes, high rate of GWG in the second trimester was associated with higher birth weight (β = 356 g, p = 0.001) and length (β = 0.85 cm, p = 0.002). First and third trimester GWG were not associated with neonatal size. CONCLUSIONS The trimester specific pattern and rate of GWG reflect changes in maternal body fat and body water, and are associated with neonatal size, which supports the importance of monitoring trimester-specific GWG.
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Sanchez PG, Rouse M, Pratt DL, Kon ZN, Pierson RN, Rajagopal K, Iacono AT, Pham SM, Griffith BP. Lung Donation After Controlled Circulatory Determination of Death: A Review of Current Practices and Outcomes. Transplant Proc 2016; 47:1958-65. [PMID: 26293081 DOI: 10.1016/j.transproceed.2015.06.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 06/08/2015] [Accepted: 06/16/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND Since the first reported series in 1995, transplantation of lungs recovered through donation after circulatory determination of death (DCDD) has steadily increased. In some European and Australian centers, controlled DCDD accounts for 15% to 30% of all transplanted lungs. Several transplant centers have reported early and midterm outcomes similar to those associated with the use of donors after brain death. Despite these encouraging reports, less than 2% of all lung transplants in the United States are performed using donors after circulatory determination of death. METHODS An electronic search from January 1990 to January 2014 was performed to identify series reporting lung transplant outcomes using controlled DCDD. Data from these publications were analyzed in terms of donor characteristics, donation after circulatory determination of death protocols, recipients' characteristics, and early and midterm outcomes. RESULTS Two hundred twenty-two DCDDs were transplanted into 225 recipients. The rate of primary graft dysfunction grade 3 ranged from 3% to 36%. The need for extracorporeal membrane oxygenation support after transplantation ranged from 0% to 18%. The average intensive care unit stay ranged from 4 to 8.5 days and the average hospital stay ranged from 14 to 35 days. Thirty-day mortality ranged from 0% to 11% and 1-year survival from 88% to 100%. CONCLUSION Under clinical protocols developed and strictly applied by several experienced lung transplant programs, lungs from controlled DCDD have produced outcomes very similar to those observed with brain death donors.
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Timofte I, Terrin M, Barr E, Sanchez P, Kim J, Reed R, Britt E, Ravichandran B, Rajagopal K, Griffith B, Pham S, Pierson RN, Iacono A. Belatacept for renal rescue in lung transplant patients. Transpl Int 2016; 29:453-63. [PMID: 26678245 DOI: 10.1111/tri.12731] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 08/19/2015] [Accepted: 12/09/2015] [Indexed: 11/28/2022]
Abstract
Renal failure causes morbidity and mortality after lung transplantation and is aggravated by exposure to nephrotoxic immunosuppressant (IS) drugs. We report an off-label experience using belatacept for lung transplant recipients with severe renal insufficiency to reduce nephrotoxic IS exposure. We analyzed data retrospectively from a consecutive series of lung transplant patients with renal insufficiency in whom belatacept treatment was initiated between June 2012 and June 2014 at the University of Maryland Medical Center. Eight patients received belatacept because of acute or chronic renal insufficiency (median) GFR 24 (IQR 18-26). Glomerular filtration rate (GFR) remained stable in two patients and increased in five. One patient with established renal and respiratory failure received only the induction dose of belatacept and died 4 months later of respiratory and multisystem organ failure. Calcineurin inhibitor or sirolimus exposure was safely withheld or reduced without moderate or severe acute rejection during ongoing belatacept in the other seven patients. FEV1 remained stable over the 6-month study interval. Belatacept use appears to permit safe transient reduction in conventional immunosuppressive therapy and was associated with stable or improved renal function in a small retrospective series of lung transplant recipients with acute or chronic renal insufficiency.
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Abstract
Generation of an effective immune response against foreign antigens requires two distinct molecular signals: a primary signal provided by the binding of antigen-specific T-cell receptor to peptide-MHC on antigen-presenting cells and a secondary signal delivered via the engagement of costimulatory molecules. Among various costimulatory signaling pathways, the interactions between CD40 and its ligand CD154 have been extensively investigated given their essential roles in the modulation of adaptive immunity. Here, we review current understanding of the role CD40/CD154 costimulation pathway has in alloimmunity, and summarize recent mechanistic and preclinical advances in the evaluation of candidate therapeutic approaches to target this receptor-ligand pair in transplantation.
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Kubicki N, Laird C, Burdorf L, Pierson RN, Azimzadeh AM. Current status of pig lung xenotransplantation. Int J Surg 2015; 23:247-254. [PMID: 26278663 DOI: 10.1016/j.ijsu.2015.08.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 07/27/2015] [Accepted: 08/04/2015] [Indexed: 12/15/2022]
Abstract
Human organ transplantation has improved duration and quality of life for many people, but its full potential is critically limited by short supply of available organs. One solution is xenotransplantation, although this comes with its own set of challenges. Lungs in particular are highly sensitive to injury, during the transplantation process generally, and to multiple immune rejection mechanisms. Using pig lung donors, our lab has been working on lung transplants into baboons as a surrogate for a human recipient. Several ex vivo human blood perfusion models have also proven useful. The combination of these experiments allows us to test large animal models as well as whole organ or isolated endothelial reactions to perfusion with human blood. We have found that a multi-modality therapeutic approach to prevent various pathogenic cascades - such as antibody-driven complement activation, other immune pathway activation, thrombosis, and tissue ischemia-reperfusion injury - has met with progressively greater success to protect the xeno lung from injury. Pig gene knockout and human gene transfer has been perhaps the greatest contributor. This review will discuss mechanisms of xeno lung injury, relevant experimental models, as well as recent results and future targets for research.
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Azimzadeh AM, Kelishadi SS, Ezzelarab MB, Singh AK, Stoddard T, Iwase H, Zhang T, Burdorf L, Sievert E, Avon C, Cheng X, Ayares D, Horvath KA, Corcoran PC, Mohiuddin MM, Barth RN, Cooper DKC, Pierson RN. Early graft failure of GalTKO pig organs in baboons is reduced by expression of a human complement pathway-regulatory protein. Xenotransplantation 2015; 22:310-6. [PMID: 26174749 DOI: 10.1111/xen.12176] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/07/2015] [Indexed: 01/24/2023]
Abstract
We describe the incidence of early graft failure (EGF, defined as loss of function from any cause within 3 days after transplant) in a large cohort of GalTKO pig organs transplanted into baboons in three centers, and the effect of additional expression of a human complement pathway-regulatory protein, CD46 or CD55 (GalTKO.hCPRP). Baboon recipients of life-supporting GalTKO kidney (n = 7) or heterotopic heart (n = 14) grafts received either no immunosuppression (n = 4), or one of several partial or full immunosuppressive regimens (n = 17). Fourteen additional baboons received a GalTKO.hCPRP kidney (n = 5) or heart (n = 9) and similar treatment regimens. Immunologic, pathologic, and coagulation parameters were measured at frequent intervals. EGF of GalTKO organs occurred in 9/21 baboons (43%). hCPRP expression reduced the GalTKO EGF incidence to 7% (1/14; P < 0.01 vs. GalTKO alone). At 30 mins, complement deposits were more intense in organs in which EGF developed (P < 0.005). The intensity of peri-transplant platelet activation (as β-thromboglobulin release) correlated with EGF, as did the cumulative coagulation score (P < 0.01). We conclude that (i) the transgenic expression of a hCPRP on the vascular endothelium of a GalTKO pig reduces the incidence of EGF and reduces complement deposition, (ii) complement deposition and platelet activation correlate with early GalTKO organ failure, and (iii) the expression of a hCPRP reduces EGF but does not prevent systemic coagulation activation. Additional strategies will be required to control coagulation activation.
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Harris DG, Benipal PK, Cheng X, Burdorf L, Azimzadeh AM, Pierson RN. Four-dimensional characterization of thrombosis in a live-cell, shear-flow assay: development and application to xenotransplantation. PLoS One 2015; 10:e0123015. [PMID: 25830912 PMCID: PMC4382176 DOI: 10.1371/journal.pone.0123015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 02/26/2015] [Indexed: 02/01/2023] Open
Abstract
Background Porcine xenografts are a promising source of scarce transplantable organs, but stimulate intense thrombosis of human blood despite targeted genetic and pharmacologic interventions. Current experimental models do not enable study of the blood/endothelial interface to investigate adhesive interactions and thrombosis at the cellular level under physiologic conditions. The purpose of this study was to develop and validate a live-cell, shear-flow based thrombosis assay relevant to general thrombosis research, and demonstrate its potential in xenotransplantation applications. Methodology/Principal Findings Confluent wild-type (WT, n = 48) and Gal transferase knock-out (GalTKO, which resist hyperacute rejection; n = 11) porcine endothelia were cultured in microfluidic channels. To mimic microcirculatory flow, channels were perfused at 5 dynes/cm2 and 37°C with human blood stained to fluorescently label platelets. Serial fluorescent imaging visualized percent surface area coverage (SA, for adhesion of labeled cells) and total fluorescence (a metric of clot volume). Aggregation was calculated by the fluorescence/SA ratio (FR). WT endothelia stimulated diffuse platelet adhesion (SA 65 ± 2%) and aggregation (FR 120 ± 1 a.u.), indicating high-grade thrombosis consistent with the rapid platelet activation and consumption seen in whole-organ lung xenotransplantation models. Experiments with antibody blockade of platelet aggregation, and perfusion of syngeneic and allo-incompatible endothelium was used to verify the biologic specificity and validity of the assay. Finally, with GalTKO endothelia thrombus volume decreased by 60%, due primarily to a 58% reduction in adhesion (P < 0.0001 each); importantly, aggregation was only marginally affected (11% reduction, P < 0.0001). Conclusions/Significance This novel, high-throughput assay enabled dynamic modeling of whole-blood thrombosis on intact endothelium under physiologic conditions, and allowed mechanistic characterization of endothelial and platelet interactions. Applied to xenogeneic thrombosis, it enables future studies regarding the effect of modifying the porcine genotype on sheer-stress-dependent events that characterize xenograft injury. This in-vitro platform is likely to prove broadly useful to study thrombosis and endothelial interactions under dynamic physiologic conditions.
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Harris DG, Quinn KJ, French BM, Schwartz E, Kang E, Dahi S, Phelps CJ, Ayares DL, Burdorf L, Azimzadeh AM, Pierson RN. Meta-analysis of the independent and cumulative effects of multiple genetic modifications on pig lung xenograft performance during ex vivo perfusion with human blood. Xenotransplantation 2015; 22:102-11. [PMID: 25470239 PMCID: PMC4390422 DOI: 10.1111/xen.12149] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 11/01/2014] [Indexed: 12/31/2022]
Abstract
BACKGROUND Genetically modified pigs are a promising potential source of lung xenografts. Ex vivo xenoperfusion is an effective platform for testing the effect of new modifications, but typical experiments are limited by testing of a single genetic intervention and small sample sizes. The purpose of this study was to analyze the individual and aggregate effects of donor genetic modifications on porcine lung xenograft survival and injury in an extensive pig lung xenoperfusion series. METHODS Data from 157 porcine lung xenoperfusion experiments using otherwise unmodified heparinized human blood were aggregated as either continuous or dichotomous variables. Lungs were wild type in 17 perfusions (11% of the study group), while 31 lungs (20% of the study group) had one genetic modification, 40 lungs (39%) had 2, and 47 lungs (30%) had 3 or more modifications. The primary endpoint was functional lung survival to 4 h of perfusion. Secondary analyses evaluated previously identified markers associated with known lung xenograft injury mechanisms. In addition to comparison among all xenografts grouped by survival status, a subgroup analysis was performed of lungs incorporating the GalTKO.hCD46 genotype. RESULTS Each increase in the number of genetic modifications was associated with additional prolongation of lung xenograft survival. Lungs that exhibited survival to 4 h generally had reduced platelet activation and thrombin generation. GalTKO and the expression of hCD46, HO-1, hCD55, or hEPCR were associated with improved survival. hTBM, HLA-E, and hCD39 were associated with no significant effect on the primary outcome. CONCLUSION This meta-analysis of an extensive lung xenotransplantation series demonstrates that increasing the number of genetic modifications targeting known xenogeneic lung injury mechanisms is associated with incremental improvements in lung survival. While more detailed mechanistic studies are needed to explore the relationship between gene expression and pathway-specific injury and explore why some genes apparently exhibit neutral (hTBM, HLA-E) or inconclusive (CD39) effects, GalTKO, hCD46, HO-1, hCD55, and hEPCR modifications were associated with significant lung xenograft protection. This analysis supports the hypothesis that multiple genetic modifications targeting different known mechanisms of xenograft injury will be required to optimize lung xenograft survival.
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Cooper DKC, Buhler L, Breimer M, Korsgren O, Tibell A, Wennberg L, Cozzi E, d'Apice AJF, Hering B, McKenzie IFC, Pierson RN, Sykes M, Kobayashi T. Tribute to Carl-Gustav Groth (1933-2014), first president of the International Xenotransplantation Association. Xenotransplantation 2014; 21:97-8. [PMID: 25268247 DOI: 10.1111/xen.12098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ezzelarab MB, Ekser B, Azimzadeh A, Lin CC, Zhao Y, Rodriguez R, Echeverri GJ, Iwase H, Long C, Hara H, Ayares D, Pierson RN, Thomson AW, Cooper DK. Systemic inflammation in xenograft recipients precedes activation of coagulation. Xenotransplantation 2014; 22:32-47. [PMID: 25209710 DOI: 10.1111/xen.12133] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 07/25/2014] [Indexed: 01/21/2023]
Abstract
BACKGROUND Dysregulation of coagulation is considered a major barrier against successful pig organ xenotransplantation in non-human primates. Inflammation is known to promote activation of coagulation. The role of pro-inflammatory factors as well as the relationship between inflammation and activation of coagulation in xenograft recipients is poorly understood. METHODS Baboons received kidney (n=3), heart (n=4), or artery patch (n=8) xenografts from α1,3-galactosyltransferase gene-knockout (GTKO) pigs or GTKO pigs additionally transgenic for human complement-regulatory protein CD46 (GTKO/CD46). Immunosuppression (IS) was based on either CTLA4Ig or anti-CD154 costimulation blockade. Three artery patch recipients did not receive IS. Pro-inflammatory cytokines, chemokines, and coagulation parameters were evaluated in the circulation after transplantation. In artery patch recipients, monocytes and dendritic cells (DC) were monitored in peripheral blood. Expression of tissue factor (TF) and CD40 on monocytes and DC were assessed by flow cytometry. C-reactive protein (C-RP) levels in the blood and C-RP deposition in xenografts as well as native organs were evaluated. Baboon and pig C-RP mRNA in heart and kidney xenografts were evaluated. RESULTS In heart and kidney xenograft recipients, the levels of INFγ, TNF-α, IL-12, and IL-8 were not significantly higher after transplantation. However, MCP-1 and IL-6 levels were significantly higher after transplantation, particularly in kidney recipients. Elevated C-RP levels preceded activation of coagulation in heart and kidney recipients, where high levels of C-RP were maintained until the time of euthanasia in both heart and kidney recipients. In artery patch recipients, INFγ, TNF-α, IL-12, IL-8, and MCP-1 were elevated with no IS, while IL-6 was not. With IS, INFγ, TNF-α, IL-12, IL-8, and MCP-1 were reduced, but IL-6 was elevated. Elevated IL-6 levels were observed as early as 2 weeks in artery patch recipients. While IS was associated with reduced thrombin activation, fibrinogen and C-RP levels were increased when IS was given. There was a significant positive correlation between C-RP, IL-6, and fibrinogen levels. Additionally, absolute numbers of monocytes were significantly increased when IS was given, but not without IS. This was associated with increased CD40 and TF expression on CD14+ monocytes and lineage(neg) CD11c+ DC, with increased differentiation of the pro-inflammatory CD14+ CD11c+ monocyte population. At the time of euthanasia, C-RP deposition in kidney and heart xenografts, C-RP positive cells in artery patch xenograft and native lungs were detected. Finally, high levels of both pig and baboon C-RP mRNA were detected in heart and kidney xenografts. CONCLUSIONS Inflammatory responses precede activation of coagulation after organ xenotransplantation. Early upregulation of C-RP and IL-6 levels may amplify activation of coagulation through upregulation of TF on innate immune cells. Prevention of systemic inflammation in xenograft recipients (SIXR) may be required to prevent dysregulation of coagulation and avoid excessive IS after xenotransplantation.
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Azimzadeh AM, Byrne GW, Ezzelarab M, Welty E, Braileanu G, Cheng X, Robson SC, McGregor CGA, Cooper DKC, Pierson RN. Development of a consensus protocol to quantify primate anti-non-Gal xenoreactive antibodies using pig aortic endothelial cells. Xenotransplantation 2014; 21:555-66. [PMID: 25176173 DOI: 10.1111/xen.12125] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 05/30/2014] [Indexed: 01/05/2023]
Abstract
BACKGROUND Scientists working in the field of xenotransplantation do not employ a uniform method to measure and report natural and induced antibody responses to non-Galα(1,3)Gal (non-Gal) epitopes. Such humoral responses are thought to be particularly pathogenic after transplantation of vascularized GalTKO pig organs and having a more uniform assay and reporting format would greatly facilitate comparisons between laboratories. METHODS Flow cytometry allows examination of antibody reactivity to intact antigens in their natural location and conformation on cell membranes. We have established a simple and reproducible flow cytometric assay to detect antibodies specific for non-Gal pig antigens using primary porcine aortic endothelial cells (pAECs) and cell culture-adapted pAEC cell lines generated from wild type and α1,3galactosyl transferase knockout (GalTKO) swine. RESULTS The consensus protocol we propose here is based on procedures routinely used in four xenotransplantation centers and was independently evaluated at three sites using shared cells and serum samples. Our observation support use of the cell culture-adapted GalTKO pAEC KO:15502 cells as a routine method to determine the reactivity of anti-non-Gal antibodies in human and baboon serum. CONCLUSIONS We have developed an assay that allows the detection of natural and induced non-Gal xenoreactive antibodies present in human or baboon serum in a reliable and consistent manner. This consensus assay and format for reporting the data should be accessible to laboratories and will be useful for assessing experimental results between multiple research centers. Adopting this assay and format for reporting the data should facilitate the detection, monitoring, and detailed characterization of non-Gal antibody responses.
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Kim MK, Choi HJ, Kwon I, Pierson RN, Cooper DKC, Soulillou JP, O'Connell PJ, Vabres B, Maeda N, Hara H, Scobie L, Gianello P, Takeuchi Y, Yamada K, Hwang ES, Kim SJ, Park CG. The International Xenotransplantation Association consensus statement on conditions for undertaking clinical trials of xenocorneal transplantation. Xenotransplantation 2014; 21:420-30. [PMID: 25176471 DOI: 10.1111/xen.12129] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Accepted: 06/20/2014] [Indexed: 11/27/2022]
Abstract
To develop an international consensus regarding the appropriate conditions for undertaking clinical trials in xenocorneal transplantation, here we review specific ethical, logistical, scientific, and regulatory issues regarding xenocorneal transplantation, and propose guidelines for conduct of clinical xenocorneal transplantation trials. These proposed guidelines are modeled on the published consensus statement of the International Xenotransplantation Association regarding recommended guidelines for conduct of clinical islet xenotransplantation. It is expected that this initial consensus statement will be revised over time in response to scientific advances in the field, and changes in the regulatory framework based on accumulating clinical experience.
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Harris DG, Quinn KJ, Dahi S, Burdorf L, Azimzadeh AM, Pierson RN. Lung xenotransplantation: recent progress and current status. Xenotransplantation 2014; 21:496-506. [PMID: 25040467 DOI: 10.1111/xen.12116] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 05/05/2014] [Indexed: 12/22/2022]
Abstract
Xenotransplantation has undergone important progress in controlling initial hyperacute rejection in many preclinical models, with some cell, tissue, and organ xenografts advancing toward clinical trials. However, acute injury, driven primarily by innate immune and inflammatory responses, continues to limit results in lung xenograft models. The purpose of this article is to review the current status of lung xenotransplantation--including the seemingly unique challenges posed by this organ-and summarize proven and emerging means of overcoming acute lung xenograft injury.
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Burdorf L, Stoddard T, Zhang T, Rybak E, Riner A, Avon C, Laaris A, Cheng X, Sievert E, Braileanu G, Newton A, Phelps CJ, Ayares D, Azimzadeh AM, Pierson RN. Expression of human CD46 modulates inflammation associated with GalTKO lung xenograft injury. Am J Transplant 2014; 14:1084-95. [PMID: 24698431 PMCID: PMC4144189 DOI: 10.1111/ajt.12673] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 12/06/2013] [Accepted: 01/12/2014] [Indexed: 01/25/2023]
Abstract
Evaluation of lungs from GalTKO.hCD46 pigs, genetically modified to lack the galactose-α(1,3)-galactose epitope (GalTKO) and to express human CD46, a complement regulatory protein, has not previously been described. Physiologic, hematologic and biochemical parameters during perfusion with heparinized fresh human blood were measured for 33 GalTKO.hCD46, GalTKO (n = 16), and WT pig lungs (n = 16), and 12 pig lungs perfused with autologous pig blood. Median GalTKO.hCD46 lung survival was 171 min compared to 120 for GalTKO (p = 0.27) and 10 for WT lungs (p < 0.001). Complement activation, platelet activation and histamine elaboration were significantly reduced during the first 2 h of perfusion in GalTKO.hCD46 lungs compared to GalTKO (ΔC3a at 120' 812 ± 230 vs. 1412 ± 1047, p = 0.02; ΔCD62P at 120' 9.8 ± 7.2 vs. 25.4 ± 18.2, p < 0.01; Δhistamine at 60' 97 ± 62 vs. 189 ± 194, p = 0.03). We conclude that, in addition to significant down-modulation of complement activation, hCD46 expression in GalTKO lungs diminished platelet and coagulation cascade activation, neutrophil sequestration and histamine release. Because GalTKO.hCD46 lung failure kinetics correlated directly with platelet and neutrophil sequestration, coagulation cascade activation and a rise in histamine levels within the first hour of perfusion, further progress will likely depend upon improved control of these pathways, by rationally targeted additional modifications to pigs and pharmacologic interventions.
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LaMattina JC, Burdorf L, Zhang T, Rybak E, Cheng X, Munivenkatappa R, Salles II, Broos K, Sievert E, McCormick B, Decarlo M, Ayares D, Deckmyn H, Azimzadeh AM, Pierson RN, Barth RN. Pig-to-baboon liver xenoperfusion utilizing GalTKO.hCD46 pigs and glycoprotein Ib blockade. Xenotransplantation 2014; 21:274-86. [PMID: 24628649 DOI: 10.1111/xen.12093] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 02/05/2014] [Indexed: 12/15/2022]
Abstract
BACKGROUND Although transplantation of genetically modified porcine livers into baboons has yielded recipient survival for up to 7 days, survival is limited by profound thrombocytopenia, which becomes manifest almost immediately after revascularization, and by subsequent coagulopathy. Porcine von Willebrand's factor (VWF), a glycoprotein that adheres to activated platelets to initiate thrombus formation, has been shown to constitutively activate human platelets via their glycoprotein Ib (GPIb) receptors. Here, we report our pig-to-primate liver xenoperfusion model and evaluate whether targeting the GPIb-VWF axis prevents platelet sequestration. METHODS Twelve baboons underwent cross-circulation with the following extracorporeal livers: one allogeneic control with a baboon liver, 4 xenogeneic controls with a GalTKO.hCD46 pig liver, 3 GalTKO.hCD46 pig livers in recipients treated with αGPIb antibody during perfusion, and 4 GalTKO.hCD46 pig livers pre-treated with D-arginine vasopressin (DDAVP) in recipients treated with αGPIb antibody during perfusion. RESULTS All perfused livers appeared grossly and macroscopically normal and produced bile. Xenograft liver perfusion experiments treated with αGPIb antibody may show less platelet sequestration during the initial 2 h of perfusion. Portal venous resistance remained constant in all perfusion experiments. Platelet activation studies demonstrated platelet activation in all xenoperfusions, but not in the allogeneic perfusion. CONCLUSION These observations suggest that primate platelet sequestration by porcine liver and the associated thrombocytopenia are multifactorial and perhaps partially mediated by a constitutive interaction between porcine VWF and the primate GPIb receptor. Control of platelet sequestration and consumptive coagulopathy in liver xenotransplantation will likely require a multifaceted approach in our clinically relevant perfusion model.
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