19 results on '"Reichart, Bruno"'
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2. Multiple genetically modified GTKO/hCD46/HLA-E/hβ2-mg porcine hearts are protected from complement activation and natural killer cell infiltration during ex vivo perfusion with human blood.
- Author
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Abicht JM, Sfriso R, Reichart B, Längin M, Gahle K, Puga Yung GL, Seebach JD, Rieben R, Ayares D, Wolf E, Klymiuk N, Baehr A, Kind A, Mayr T, and Bauer A
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- Animals, Endothelial Cells immunology, Humans, Leukocytes metabolism, Myocardium immunology, Swine, Transplantation, Heterologous methods, Animals, Genetically Modified immunology, Complement Activation immunology, Heart, Heterografts immunology, Killer Cells, Natural immunology
- Abstract
Background: In pig-to-human xenotransplantation, early cellular rejection reactions are mediated by natural killer cells (NK cells). Human NK cells are inhibited by HLA-E via CD94/NKG2A receptors. To protect porcine grafts against human NK cell responses, transgenic GTKO pigs expressing hCD46 and HLA-E have been generated. The aim of this study was to test the effect of this genetic modification on xenogeneic, and in particular human NK cell response, using an ex vivo perfusion model of pig hearts with human blood., Methods: Cardiopleged and explanted genetically modified (gm) pig hearts (GTKO/hCD46/HLA-E/hβ2-microglobulin) and wild-type (wt) controls (n = 6 each) were reperfused and tested in an 8 hours ex vivo perfusion system using freshly drawn human blood. Cardiac function was evaluated during a 165-minute period in working heart mode. Myocardial damage, antibody deposition, complement activation, and coagulation parameters were evaluated histologically at the end of perfusion. The number of NK cells in the perfusate was determined by flow cytometry at baseline and at 8 hours; tissue infiltration by NK cells was quantified by immunofluorescence microscopy using NKp46 staining of frozen sections., Results: Deposition of IgG (1.2 ± 1 × 10
7 vs 8.8 ± 2.9 × 106 ; P < .01), IgM (4.4 ± 3.7 × 106 vs 1.7 ± 1.2 × 106 ; P < .01), and the complement activation product C4b/c (3.5 ± 1.3 × 106 vs 2.3 × 106 ± 9.4 × 105 ; P > .01) was lower in gm than wt hearts. NK cell percentages of leukocytes in the perfusate decreased from 0.94 ± 0.77% to 0.21 ± 0.25% (P = .04) during xenoperfusion of wt hearts. In contrast, the ratio of NK cells did not decrease significantly in the gm hearts. In this group, NK cell myocardial infiltration after 480 minutes of perfusion was lower than in wt organs (2.5 ± 3.7 × 104 /mm3 vs 1.3 ± 1.4 × 105 /mm3 ; P = .0001). The function of gm hearts was better preserved compared to wt organs, as demonstrated by higher cardiac index during the first 2 hours of ex vivo perfusion., Conclusion: GTKO, hCD46, and HLA-E expression in porcine hearts reduced complement deposition, complement dependent injury, and myocardial NK cell infiltration during perfusion with human blood. This tested combination of genetic modifications may minimize damage from acute human-anti-pig rejection reactions and improve myocardial function after xenotransplantation., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)- Published
- 2018
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3. Large-Animal Biventricular Working Heart Perfusion System with Low Priming Volume-Comparison between in vivo and ex vivo Cardiac Function.
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Abicht JM, Mayr TAJ, Jauch J, Guethoff S, Buchholz S, Reichart B, and Bauer A
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- Animals, Biopsy, Echocardiography, Energy Metabolism, Heart diagnostic imaging, Myocardium metabolism, Myocardium pathology, Reproducibility of Results, Sus scrofa, Time Factors, Heart physiology, Hemodynamics, Isolated Heart Preparation methods, Perfusion methods, Ventricular Function, Left, Ventricular Function, Right
- Abstract
Background: Existing large-animal, ex vivo, cardiac perfusion models are restricted in their ability to establish an ischemia/reperfusion condition as seen in cardiac surgery or transplantation. Other working heart systems only challenge one ventricle or require a substantially larger priming volume. We describe a novel biventricular cardiac perfusion system with reduced priming volume., Methods: Juvenile pig hearts were cardiopleged, explanted, and reperfused ex vivo after 150 minutes of cold ischemia. Autologous whole blood was used as perfusate (minimal priming volume 350 mL). After 15 minutes of Langendorff perfusion (LM), the system was switched into a biventricular working mode (WM) and studied for 3 hours., Results: During reperfusion, complete unloading of both ventricles and constant-pressure coronary perfusion was achieved. During working mode perfusion, the preload and afterload pressure of both ventricles was controlled within the targeted physiologic range. Functional parameters such as left ventricular work index were reduced in ex vivo working mode (in vivo: 787 ± 186 vs. 1 h WM 498 ± 66 mm Hg·mL/g·min; p < 0.01), but remained stable throughout the following study period (3 h WM 517 ± 103 mm Hg·mL/g·min; p = 0.63). Along with the elevated workload during WM, myocardial metabolism and oxygen consumption increased compared with LM (0.021 ± 0.08 vs. 0.06 ± 0.01 mL/min/g; 1 h after reperfusion). Histologic examination of the myocardium revealed no structural damage., Conclusion: In the ex vivo perfusion system, stable hemodynamic and metabolic conditions can be established for a period of 3 hours while functional and blood parameters are easily accessible. Moreover, because of the minimal priming volume, the novel ex vivo cardiac perfusion circuit allows for autologous perfusion, using the limited amount of blood available from the organ donating animal., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Georg Thieme Verlag KG Stuttgart · New York.)
- Published
- 2018
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4. Ribonuclease (RNase) Prolongs Survival of Grafts in Experimental Heart Transplantation.
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Kleinert E, Langenmayer MC, Reichart B, Kindermann J, Griemert B, Blutke A, Troidl K, Mayr T, Grantzow T, Noyan F, Abicht JM, Fischer S, Preissner KT, Wanke R, Deindl E, and Guethoff S
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- Animals, Cattle, Cell Proliferation drug effects, Edema immunology, Edema pathology, Humans, Male, Myocardial Reperfusion Injury pathology, Rats, Rats, Inbred BN, Rats, Inbred Lew, T-Lymphocytes drug effects, Thrombosis immunology, Thrombosis pathology, Transplantation, Homologous, Graft Survival drug effects, Heart drug effects, Heart Transplantation, Myocardial Reperfusion Injury immunology, Myocardium pathology, Ribonuclease, Pancreatic pharmacology
- Abstract
Background: Cell damage, tissue and vascular injury are associated with the exposure and release of intracellular components such as RNA, which promote inflammatory reactions and thrombosis. Based on the counteracting anti-inflammatory and cardioprotective functions of ribonuclease A (RNase A) in this context, its role in an experimental model of heart transplantation in rats was studied., Methods and Results: Inbred BN/OrlRj rat cardiac allografts were heterotopically transplanted into inbred LEW/OrlRj rats. Recipients were intravenously treated every other day with saline or bovine pancreatic RNase A (50 μg/kg). Toxic side effects were not found (macroscopically and histologically). Heart tissue flow cytometry and quantitative morphological analyses of explanted hearts at postoperative day 1 or postoperative day 4 showed reduced leukocyte infiltration, edema, and thrombus formation in RNase A-treated rats. In allogeneic mixed lymphocyte reactions, RNase A decreased the proliferation of effector T cells. RNase A treatment of rats resulted in prolonged median graft survival up to 10.5 days (interquartile range 1.8) compared to 6.5 days (interquartile range 1.0) in saline treatment (P=0.001). Treatment of rats with a new generated (recombinant) human pancreatic RNase 1 prolonged median graft survival similarly, unlike treatment with (recombinant) inactive human RNase 1 (each 50 μg/kg IV every other day, 11.0 days, interquartile range 0.3, versus 8.0 days, interquartile range 0.5, P=0.007)., Conclusions: Upon heart transplantation, RNase administration appears to present a promising and safe drug to counteract ischemia/reperfusion injury and graft rejection. Furthermore, RNase treatment may be considered in situations of critical reperfusion after percutaneous coronary interventions or in cardiac surgery using the heart-lung machine., (© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)
- Published
- 2016
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5. Reduced fibrin deposition and intravascular thrombosis in hDAF transgenic pig hearts perfused with tirofiban.
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Brandl U, Jöckle H, Erhardt M, Michel S, Burdorf L, Brenner P, Bittmann I, Rössle M, Mordstein V, Hammer C, Thein E, Reichart B, and Schmoeckel M
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- Adult, Animals, Animals, Genetically Modified, Antibodies blood, Complement C3 metabolism, Complement C4 metabolism, Creatine Kinase metabolism, Disaccharides immunology, Heart Transplantation physiology, Humans, Male, Myocardium enzymology, Swine, Thrombosis mortality, Tirofiban, Transplantation, Heterologous physiology, Tyrosine therapeutic use, CD55 Antigens genetics, Fibrin metabolism, Fibrinolytic Agents therapeutic use, Heart physiology, Myocardium pathology, Thrombosis prevention & control, Tyrosine analogs & derivatives
- Abstract
Background: Solid organ xenograft rejection is associated with vascular injury resulting at least in part in platelet activation, and rejected xenografts invariably demonstrate intravascular thrombosis and interstitial hemorrhage. Complement activation plays a prominent role in platelet-endothelial interaction. We tested the effects of platelet GPIIb/IIIa inhibitor tirofiban during perfusion of hDAF pig hearts., Methods: Using a working-heart model, nontransgenic and hDAF pig hearts were perfused with tirofiban or human blood only. Myocardial damage was determined by hemodynamic parameters (cardiac output, stroke work index) and creatine phosphokinase. Further monitoring included the assessment of complement factors (C3, C4), platelets, fibrinogen, ATIII, and graft histology., Results: Tirofiban increased cardiac output (CO) and stroke work index (SWI) of nontransgenic pig hearts and improved superior CO and SWI of hDAF pig hearts. Although perfusion time of nontransgenic pig hearts was prolonged by tirofiban (196+/-65 min vs. 162+/-122 min), a similar effect in hDAF pig hearts (218+/-116 min vs. 222+/-30 min) could not be demonstrated. Tirofiban reduced consumption of C3 and C4 independently from hDAF. Depletion of fibrinogen was equally diminished by tirofiban and hDAF; the combination of both agents obtained no further reduction. ATIII consumption was most effectively inhibited by this combination. Intravascular fibrin deposition was reduced by tirofiban and hDAF, but particularly by the combination of the two agents., Conclusions: Improvement of heart performance and reduction of myocardial damage and intravascular thrombosis confirm a role of the GPIIb/IIIa inhibitor tirofiban for the prevention of hDAF pig heart rejection and xenograft function.
- Published
- 2007
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6. Effect of diabetes mellitus on sympathetic neuronal regeneration studied in the model of transplant reinnervation.
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Bengel FM, Ueberfuhr P, Schäfer D, Nekolla SG, Reichart B, and Schwaiger M
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- Catecholamines metabolism, Diabetes Mellitus diagnostic imaging, Female, Heart diagnostic imaging, Humans, Male, Middle Aged, Myocardium metabolism, Radionuclide Imaging, Recovery of Function physiology, Diabetes Mellitus physiopathology, Heart innervation, Heart physiopathology, Heart Transplantation physiology, Nerve Regeneration physiology, Sympathetic Nervous System physiopathology
- Abstract
Unlabelled: The transplanted heart is initially denervated but undergoes subsequent sympathetic reinnervation. It thus provides a unique model for studying regeneration as a specific component of autonomic nerve biology. The aim of this study was to determine the effect of diabetes mellitus on the regenerational capacity of sympathetic neurons using molecule-targeted PET., Methods: Twenty-two nonrejecting, otherwise healthy cardiac transplant recipients underwent PET with the (11)C-labeled physiologic neurotransmitter epinephrine at 4.0 +/- 3.3 y after surgery. Sympathetic reinnervation was defined as regional restoration of epinephrine retention to values within normal limits., Results: Reinnervation was observed in 8 of 12 patients with no evidence of diabetes and in 6 of 10 patients with a long-term history of diabetes mellitus. The regional extent of reinnervation (4.7% +/- 5.3% of left ventricle vs. 19.1% +/- 20.6% for nondiabetic recipients, P = 0.04) and the regeneration rate (0.8% +/- 1.0% of left ventricle per year vs. 8.0% +/- 10.1% for nondiabetic recipients, P = 0.04) were significantly reduced in diabetic subjects. In a multivariate model, diabetes mellitus was an independent determinant of allograft reinnervation. Finally, the reappearance of innervation was found to correlate with an improved chronotropic and inotropic response to stress in a standardized, symptom-limited exercise test including radionuclide angiography., Conclusion: The regenerational capacity of the sympathetic nervous system of the heart is reduced, but not abolished, by diabetes mellitus. This study on cardiac transplant recipients further supports a general link between impaired glucose handling and cardiac autonomic nerve function.
- Published
- 2006
7. Xenotransplantation von Organen
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Schmoeckel, Michael, Längin, Matthias, Reichart, Bruno, Abicht, Jan-Michael, Bender, Martin, Denner, Joachim, Marckmann, Georg, Brenner, Paolo, Wolf, Eckhard, and Hagl, Christian
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- 2024
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8. Combination of Anti-CD40 and Anti-CD40L Antibodies as Co-Stimulation Blockade in Preclinical Cardiac Xenotransplantation.
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Bender, Martin, Abicht, Jan-Michael, Reichart, Bruno, Neumann, Elisabeth, Radan, Julia, Mokelke, Maren, Buttgereit, Ines, Leuschen, Maria, Wall, Felicia, Michel, Sebastian, Ellgass, Reinhard, Steen, Stig, Paskevicius, Audrius, Lange, Andreas, Kessler, Barbara, Kemter, Elisabeth, Klymiuk, Nikolai, Denner, Joachim, Godehardt, Antonia W., and Tönjes, Ralf R.
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IMMUNE checkpoint proteins ,HEART transplantation ,MYCOSES ,XENOTRANSPLANTATION ,SURVIVAL rate - Abstract
The blockade of the CD40/CD40L immune checkpoint is considered essential for cardiac xenotransplantation. However, it is still unclear which single antibody directed against CD40 or CD40L (CD154), or which combination of antibodies, is better at preventing organ rejection. For example, the high doses of antibody administered in previous experiments might not be feasible for the treatment of humans, while thrombotic side effects were described for first-generation anti-CD40L antibodies. To address these issues, we conducted six orthotopic pig-to-baboon cardiac xenotransplantation experiments, combining a chimeric anti-CD40 antibody with an investigational long-acting PASylated anti-CD40L Fab fragment. The combination therapy effectively resulted in animal survival with a rate comparable to a previous study that utilized anti-CD40 monotherapy. Importantly, no incidence of thromboembolic events associated with the administration of the anti-CD40L PAS-Fab was observed. Two experiments failed early because of technical reasons, two were terminated deliberately after 90 days with the baboons in excellent condition and two were extended to 120 and 170 days, respectively. Unexpectedly, and despite the absence of any clinical signs, histopathology revealed fungal infections in all four recipients. This study provides, for the first time, insights into a combination therapy with anti-CD40/anti-CD40L antibodies to block this immune checkpoint. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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9. An Approach to Controlling Inflammation and Coagulation in Pig‐to‐Baboon Cardiac Xenotransplantation.
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Bender, Martin, Reichart, Bruno, Figueiredo, Constanca, Burgmann, Jonathan M., Leuschen, Maria, Wall, Felicia, Radan, Julia, Neumann, Elisabeth, Mokelke, Maren, Buttgereit, Ines, Michel, Sebastian, Ellgass, Reinhard, Egerer, Stefanie, Lange, Andreas, Baehr, Andrea, Kessler, Barbara, Kemter, Elisabeth, Klymiuk, Nikolai, Denner, Joachim, and Godehardt, Antonia W.
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ASPIRIN , *LEUKOCYTE count , *BLOOD coagulation disorders , *XENOTRANSPLANTATION , *HEART transplantation - Abstract
Introduction: Inflammatory responses and coagulation disorders are a relevant challenge for successful cardiac xenotransplantation on its way to the clinic. To cope with this, an effective and clinically practicable anti‐inflammatory and anti‐coagulatory regimen is needed. The inflammatory and coagulatory response can be reduced by genetic engineering of the organ‐source pigs. Furthermore, there are several therapeutic strategies to prevent or reduce inflammatory responses and coagulation disorders following xenotransplantation. However, it is still unclear, which combination of drugs should be used in the clinical setting. To elucidate this, we present data from pig‐to‐baboon orthotopic cardiac xenotransplantation experiments using a combination of several anti‐inflammatory drugs. Methods: Genetically modified piglets (GGTA1‐KO, hCD46/hTBM transgenic) were used for orthotopic cardiac xenotransplantation into captive‐bred baboons (n = 14). All animals received an anti‐inflammatory drug therapy including a C1 esterase inhibitor, an IL‐6 receptor antagonist, a TNF‐α inhibitor, and an IL‐1 receptor antagonist. As an additive medication, acetylsalicylic acid and unfractionated heparin were administered. The immunosuppressive regimen was based on CD40/CD40L co‐stimulation blockade. During the experiments, leukocyte counts, levels of C‐reactive protein (CRP) as well as systemic cytokine and chemokine levels and coagulation parameters were assessed at multiple timepoints. Four animals were excluded from further data analyses due to porcine cytomegalovirus/porcine roseolovirus (PCMV/PRV) infections (n = 2) or technical failures (n = 2). Results: Leukocyte counts showed a relevant perioperative decrease, CRP levels an increase. In the postoperative period, leukocyte counts remained consistently within normal ranges, CRP levels showed three further peaks after about 35, 50, and 80 postoperative days. Analyses of cytokines and chemokines revealed different patterns. Some cytokines, like IL‐8, increased about 2‐fold in the perioperative period, but then decreased to levels comparable to the preoperative values or even lower. Other cytokines, such as IL‐12/IL‐23, decreased in the perioperative period and stayed at these levels. Besides perioperative decreases, there were no relevant alterations observed in coagulation parameters. In summary, all parameters showed an unremarkable course with regard to inflammatory responses and coagulation disorders following cardiac xenotransplantation and thus showed the effectiveness of our approach. Conclusion: Our preclinical experience with the anti‐inflammatory drug therapy proved that controlling of inflammation and coagulation disorders in xenotransplantation is possible and well‐practicable under the condition that transmission of pathogens, especially of PCMV/PRV to the recipient is prevented because PCMV/PRV also induces inflammation and coagulation disorders. Our anti‐inflammatory regimen should also be applicable and effective in the clinical setting of cardiac xenotransplantation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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10. The Endothelial Glycocalyx in Pig-to-Baboon Cardiac Xenotransplantation—First Insights.
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Bender, Martin, Abicht, Jan-Michael, Reichart, Bruno, Leuschen, Maria, Wall, Felicia, Radan, Julia, Neumann, Elisabeth, Mokelke, Maren, Buttgereit, Ines, Michel, Sebastian, Ellgass, Reinhard, Gieseke, Katja, Steen, Stig, Paskevicius, Audrius, Denner, Joachim, Godehardt, Antonia W., Tönjes, Ralf R., Hagl, Christian, Ayares, David, and Wolf, Eckhard
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GLYCOCALYX ,XENOTRANSPLANTATION ,HEPARAN sulfate ,XENOGRAFTS ,PRESERVATION of organs, tissues, etc. ,ENDOTHELIAL cells - Abstract
Cardiac xenotransplantation has seen remarkable success in recent years and is emerging as the most promising alternative to human cardiac allotransplantation. Despite these achievements, acute vascular rejection still presents a challenge for long-term xenograft acceptance and new insights into innate and adaptive immune responses as well as detailed characterizations of signaling pathways are necessary. In allotransplantation, endothelial cells and their sugar-rich surface—the endothelial glycocalyx—are known to influence organ rejection. In xenotransplantation, however, only in vitro data exist on the role of the endothelial glycocalyx so far. Thus, in the current study, we analyzed the changes of the endothelial glycocalyx components hyaluronan, heparan sulfate and syndecan-1 after pig-to-baboon cardiac xenotransplantations in the perioperative (n = 4) and postoperative (n = 5) periods. These analyses provide first insights into changes of the endothelial glycocalyx after pig-to-baboon cardiac xenotransplantation and show that damage to the endothelial glycocalyx seems to be comparable or even less pronounced than in similar human settings when current strategies of cardiac xenotransplantation are applied. At the same time, data from the experiments where current strategies, like non-ischemic preservation, growth inhibition or porcine cytomegalovirus (a porcine roseolovirus (PCMV/PRV)) elimination could not be applied indicate that damage of the endothelial glycocalyx also plays an important role in cardiac xenotransplantation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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11. Transthoracic echocardiography is a simple tool for size matching in cardiac xenotransplantation.
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Mokelke, Maren, Bender, Martin, Reichart, Bruno, Neumann, Elisabeth, Radan, Julia, Buttgereit, Ines, Ayares, David, Wolf, Eckhard, Brenner, Paolo, Abicht, Jan‐Michael, and Längin, Matthias
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HEART size ,XENOTRANSPLANTATION ,ECHOCARDIOGRAPHY ,HEART transplantation ,BODY weight - Abstract
Background: Preoperative size matching is essential for both allogeneic and xenogeneic heart transplantation. In preclinical pig‐to‐baboon xenotransplantation experiments, porcine donor organs are usually matched to recipients by using indirect parameters, such as age and total body weight. For clinical use of xenotransplantation, a more precise method of size measurement would be desirable to guarantee a "perfect match." Here, we investigated the use of transthoracic echocardiography (TTE) and described a new method to estimate organ size prior to xenotransplantation. Methods: Hearts from n = 17 genetically modified piglets were analyzed by TTE and total heart weight (THW) was measured prior to xenotransplantation into baboons between March 2018 and April 2022. Left ventricular (LV) mass was calculated according to the previously published method by Devereux et al. and a newly adapted formula. Hearts from n = 5 sibling piglets served as controls for the determination of relative LV and right ventricular (RV) mass. After explantation, THW and LV and RV mass were measured. Results: THW correlated significantly with donor age and total body weight. The strongest correlation was found between THW and LV mass calculated by TTE. Compared to necropsy data of the control piglets, the Devereux formula underestimated both absolute and relative LV mass, whereas the adapted formula yielded better results. Combining the adapted formula and the relative LV mass data, THW can be predicted with TTE. Conclusions: We demonstrate reliable LV mass estimation by TTE for size matching prior to xenotransplantation. An adapted formula provides more accurate results of LV mass estimation than the generally used Devereux formula in the xenotransplantation setting. TTE measurement of LV mass is superior for the prediction of porcine heart sizes compared to conventional parameters such as age and total body weight. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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12. Genetic diversity, growth and heart function of Auckland Island pigs, a potential source for organ xenotransplantation.
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Lange, Andreas, Medugorac, Ivica, Ali, Asghar, Kessler, Barbara, Kurome, Mayuko, Zakhartchenko, Valeri, Hammer, Sabine E., Hauser, Andreas, Denner, Joachim, Dobenecker, Britta, Wess, Gerhard, Tan, Paul L. J., Garkavenko, Olga, Reichart, Bruno, Wolf, Eckhard, and Kemter, Elisabeth
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SOMATIC cell nuclear transfer ,GENETIC variation ,XENOTRANSPLANTATION ,SWINE ,SINGLE nucleotide polymorphisms - Abstract
One of the prerequisites for successful organ xenotransplantation is a reasonable size match between the porcine organ and the recipient's organ to be replaced. Therefore, the selection of a suitable genetic background of source pigs is important. In this study, we investigated body and organ growth, cardiac function, and genetic diversity of a colony of Auckland Island pigs established at the Center for Innovative Medical Models (CiMM), LMU Munich. Male and female Auckland Island pig kidney cells (selected to be free of porcine endogenous retrovirus C) were imported from New Zealand, and founder animals were established by somatic cell nuclear transfer (SCNT). Morphologically, Auckland Island pigs have smaller body stature compared to many domestic pig breeds, rendering their organ dimensions well‐suited for human transplantation. Furthermore, echocardiography assessments of Auckland Island pig hearts indicated normal structure and functioning across various age groups throughout the study. Single nucleotide polymorphism (SNP) analysis revealed higher runs of homozygosity (ROH) in Auckland Island pigs compared to other domestic pig breeds and demonstrated that the entire locus coding the swine leukocyte antigens (SLAs) was homozygous. Based on these findings, Auckland Island pigs represent a promising genetic background for organ xenotransplantation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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13. Hemodynamics in pig‐to‐baboon heterotopic thoracic cardiac xenotransplantation: Recovery from perioperative cardiac xenograft dysfunction and impairment by cardiac overgrowth.
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Bender, Martin, Panelli, Alessandro, Reichart, Bruno, Radan, Julia, Mokelke, Maren, Neumann, Elisabeth, Buttgereit, Ines, Michel, Sebastian, Bauer, Andreas, Fresch, Ann Kathrin, Mayr, Tanja, Werner, Fabian, Egerer, Stefanie, Bähr, Andrea, Kessler, Barbara, Klymiuk, Nikolai, Ayares, David, Wolf, Eckhard, Hagl, Christian, and Brenner, Paolo
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HEART diseases ,XENOTRANSPLANTATION ,HEMODYNAMICS ,PRESERVATION of organs, tissues, etc. ,CARDIAC output - Abstract
Introduction: Orthotopic cardiac xenotransplantation has seen notable improvement, leading to the first compassionate use in 2022. However, it remains challenging to define the clinical application of cardiac xenotransplantation, including the back‐up strategy in case of xenograft failure. In this regard, the heterotopic thoracic technique could be an alternative to the orthotopic procedure. We present hemodynamic data of heterotopic thoracic pig‐to‐baboon transplantation experiments, focusing on perioperative xenograft dysfunction and xenograft overgrowth. Methods: We used 17 genetically modified piglets as donors for heterotopic thoracic xenogeneic cardiac transplantation into captive‐bred baboons. In all animals, pressure probes were implanted in the graft's left ventricle and the recipient's ascending aorta and hemodynamic data (graft pressure, aortic pressure and recipient's heart rate) were recorded continuously. Results: Aortic pressures and heart rates of the recipients' hearts were postoperatively stable in all experiments. After reperfusion, three grafts presented with low left ventricular pressure indicating perioperative cardiac dysfunction (PCXD). These animals recovered from PCXD within 48 h under support of the recipient's heart and there was no difference in survival compared to the other 14 ones. After 48 h, graft pressure increased up to 200 mmHg in all 17 animals with two different time‐patterns. This led to a progressive gradient between graft and aortic pressure. With increasing gradient, the grafts stopped contributing to cardiac output. Grafts showed a marked weight increase from implantation to explantation. Conclusion: The heterotopic thoracic cardiac xenotransplantation technique is a possible method to overcome PCXD in early clinical trials and an experimental tool to get a better understanding of PCXD. The peculiar hemodynamic situation of increasing graft pressure but missing graft's output indicates outflow tract obstruction due to cardiac overgrowth. The heterotopic thoracic technique should be successful when using current strategies of immunosuppression, organ preservation and donor pigs with smaller body and organ size. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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14. Cardiac xenotransplantation: from concept to clinic.
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Reichart, Bruno, Cooper, David K C, Längin, Matthias, Tönjes, Ralf R, Pierson, Richard N, and Wolf, Eckhard
- Subjects
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HEART assist devices , *ORGANS (Anatomy) , *XENOTRANSPLANTATION , *HEART transplantation , *PATIENT selection , *TERMINALLY ill - Abstract
For many patients with terminal/advanced cardiac failure, heart transplantation is the most effective, durable treatment option, and offers the best prospects for a high quality of life. The number of potentially life-saving donated human organs is far fewer than the population who could benefit from a new heart, resulting in increasing numbers of patients awaiting replacement of their failing heart, high waitlist mortality, and frequent reliance on interim mechanical support for many of those deemed among the best candidates but who are deteriorating as they wait. Currently, mechanical assist devices supporting left ventricular or biventricular heart function are the only alternative to heart transplant that is in clinical use. Unfortunately, the complication rate with mechanical assistance remains high despite advances in device design and patient selection and management, and the quality of life of the patients even with good outcomes is only moderately improved. Cardiac xenotransplantation from genetically multi-modified (GM) organ-source pigs is an emerging new option as demonstrated by the consistent long-term success of heterotopic (non-life-supporting) abdominal and life-supporting orthotopic porcine heart transplantation in baboons, and by a recent 'compassionate use' transplant of the heart from a GM pig with 10 modifications into a terminally ill patient who survived for 2 months. In this review, we discuss pig heart xenotransplantation as a concept, including pathobiological aspects related to immune rejection, coagulation dysregulation, and detrimental overgrowth of the heart, as well as GM strategies in pigs to prevent or minimize these problems. Additional topics discussed include relevant results of heterotopic and orthotopic heart transplantation experiments in the pig-to-baboon model, microbiological and virologic safety concepts, and efficacy requirements for initiating formal clinical trials. An adequate regulatory and ethical framework as well as stringent criteria for the selection of patients will be critical for the safe clinical development of cardiac xenotransplantation, which we expect will be clinically tested during the next few years. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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15. Immunomodulatory therapy with thymopentin and indomethacin: successful restoration of interleukin-2 synthesis in patients undergoing major surgery
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Faist, Eugen, Markewitz, Andreas, Fuchs, Dietmar, Lang, Stefan, Zarius, Susanne, Schildberg, Friedrich-Wilhelm, Wachter, Helmut, and Reichart, Bruno
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Heart ,Immunosuppression -- Drug therapy ,Indomethacin -- Evaluation ,Drug therapy, Combination -- Evaluation ,Thymopentin -- Evaluation ,Blood -- Circulation, Artificial ,Health - Abstract
Patients who undergo heart surgery may require extracorporeal circulation, a method of oxygenating the blood in which venous blood is diverted outside the body to a heart-lung machine for oxygenation and then returned to the body. Patients who undergo this surgery receive a massive insult to their immune system as a result of the combination of tissue injury, blood transfusions, and inflammation-like state affecting the entire body from the contact between blood and foreign material. These patients have an increased susceptibility to infection. A prospective study was undertaken of 60 patients who were undergoing open heart surgery. Combination therapy with thymopentin and indomethacin was aimed at restoring the patient's immune potential. Immunologic studies were performed prior to surgery. Twenty patients received indomethacin only; 20 received both indomethacin and thymopentin; and 20 patients represented a control group, receiving no immunologic treatment. Significant restoration of immune suppression was achieved in the group that received both indomethacin and thymopentin. Patients receiving combination therapy showed restoration of impaired expression of T-cell receptors, proliferation of lymphocytes, and synthesis of interleukin-2 (a cytokine that stimulates the growth of T-cells). It is concluded that combination therapy with indomethacin and thymopentin is more effective than indomethacin alone in preserving and/or restoring immune potential as defined as intact monocyte T-cell interaction. This approach may be useful in maintaining normal immune system defenses in injured or traumatized patients. (Consumer Summary produced by Reliance Medical Information, Inc.)
- Published
- 1991
16. Genetically modified pigs as donors of cells, tissues, and organs for xenotransplantation.
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Wolf, Eckhard, Kemter, Elisabeth, Klymiuk, Nikolai, and Reichart, Bruno
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XENOTRANSPLANTATION ,ANTIGEN presenting cells ,ZOOLOGY ,SOMATIC cell nuclear transfer - Published
- 2019
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17. Multiple genetically modified GTKO/hCD46/HLA‐E/hβ2−mg porcine hearts are protected from complement activation and natural killer cell infiltration during ex vivo perfusion with human blood.
- Author
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Abicht, Jan‐Michael, Längin, Matthias, Gahle, Katja, Mayr, Tanja, Bauer, Andreas, Sfriso, Riccardo, Rieben, Robert, Reichart, Bruno, Puga Yung, Gisella L., Seebach, Jörg D., Ayares, David, Wolf, Eckhard, Klymiuk, Nikolai, Baehr, Andrea, and Kind, Alexander
- Subjects
SWINE ,XENOGRAFTS ,KILLER cells ,BIOPROSTHESIS ,BLOOD ,CARDIOMYOPATHIES ,TISSUES ,LEUCOCYTES - Abstract
Abstract: Background: In pig‐to‐human xenotransplantation, early cellular rejection reactions are mediated by natural killer cells (NK cells). Human NK cells are inhibited by HLA‐E via CD94/NKG2A receptors. To protect porcine grafts against human NK cell responses, transgenic GTKO pigs expressing hCD46 and HLA‐E have been generated. The aim of this study was to test the effect of this genetic modification on xenogeneic, and in particular human NK cell response, using an ex vivo perfusion model of pig hearts with human blood. Methods: Cardiopleged and explanted genetically modified (gm) pig hearts (GTKO/hCD46/HLA‐E/hβ2‐microglobulin) and wild‐type (wt) controls (n = 6 each) were reperfused and tested in an 8 hours ex vivo perfusion system using freshly drawn human blood. Cardiac function was evaluated during a 165‐minute period in working heart mode. Myocardial damage, antibody deposition, complement activation, and coagulation parameters were evaluated histologically at the end of perfusion. The number of NK cells in the perfusate was determined by flow cytometry at baseline and at 8 hours; tissue infiltration by NK cells was quantified by immunofluorescence microscopy using NKp46 staining of frozen sections. Results: Deposition of IgG (1.2 ± 1 × 10
7 vs 8.8 ± 2.9 × 106 ; P < .01), IgM (4.4 ± 3.7 × 106 vs 1.7 ± 1.2 × 106 ; P < .01), and the complement activation product C4b/c (3.5 ± 1.3 × 106 vs 2.3 × 106 ± 9.4 × 105 ; P > .01) was lower in gm than wt hearts. NK cell percentages of leukocytes in the perfusate decreased from 0.94 ± 0.77% to 0.21 ± 0.25% (P = .04) during xenoperfusion of wt hearts. In contrast, the ratio of NK cells did not decrease significantly in the gm hearts. In this group, NK cell myocardial infiltration after 480 minutes of perfusion was lower than in wt organs (2.5 ± 3.7 × 104 /mm3 vs 1.3 ± 1.4 × 105 /mm3 ; P = .0001). The function of gm hearts was better preserved compared to wt organs, as demonstrated by higher cardiac index during the first 2 hours of ex vivo perfusion. Conclusion: GTKO, hCD46, and HLA‐E expression in porcine hearts reduced complement deposition, complement dependent injury, and myocardial NK cell infiltration during perfusion with human blood. This tested combination of genetic modifications may minimize damage from acute human‐anti‐pig rejection reactions and improve myocardial function after xenotransplantation. [ABSTRACT FROM AUTHOR]- Published
- 2018
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18. Large-Animal Biventricular Working Heart Perfusion System with Low Priming Volume--Comparison between in vivo and ex vivo Cardiac Function.
- Author
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Jan-Michael, Abicht, Mayr, Tanja Axinja Jelena, Jauch, Judith, Guethoff, Sonja, Buchholz, Stefan, Reichart, Bruno, and Bauer, Andreas
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CARDIAC arrest ,HISTOCOMPATIBILITY antigens ,PERFUSION ,HEMODYNAMICS ,BIOLOGICAL fluid dynamics - Abstract
Background Existing large-animal, ex vivo, cardiac perfusion models are restricted in their ability to establish an ischemia/reperfusion condition as seen in cardiac surgery or transplantation. Other working heart systems only challenge one ventricle or require a substantially larger priming volume.We describe a novel biventricular cardiac perfusion system with reduced priming volume. Methods Juvenile pig hearts were cardiopleged, explanted, and reperfused ex vivo after 150 minutes of cold ischemia. Autologous whole blood was used as perfusate (minimal priming volume 350 mL). After 15 minutes of Langendorff perfusion (LM), the system was switched into a biventricular working mode (WM) and studied for 3 hours. Results During reperfusion, complete unloading of both ventricles and constantpressure coronary perfusion was achieved. During workingmode perfusion, the preload and afterload pressure of both ventricles was controlled within the targeted physiologic range. Functional parameters such as left ventricular work index were reduced in ex vivo working mode (in vivo: 787 ± 186 vs. 1 h WM 498 ± 66 mm Hg·mL/g·min; p < 0.01), but remained stable throughout the following study period (3 h WM 517 ± 103 mm Hg·mL/g·min; p ¼ 0.63). Along with the elevated workload during WM, myocardial metabolism and oxygen consumption increased compared with LM (0.021 ± 0.08 vs. 0.06 ± 0.01 mL/min/g; 1 h after reperfusion). Histologic examination of the myocardium revealed no structural damage. Conclusion In the ex vivo perfusion system, stable hemodynamic and metabolic conditions can be established for a period of 3 hours while functional and blood parameters are easily accessible.Moreover, because of the minimal priming volume, the novel ex vivo cardiac perfusion circuit allows for autologous perfusion, using the limited amount of blood available from the organ donating animal. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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19. Complement C3 inhibitor Cp40 attenuates xenoreactions in pig hearts perfused with human blood.
- Author
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Abicht, Jan‐Michael, Kourtzelis, Ioannis, Reichart, Bruno, Koutsogiannaki, Sophia, Primikyri, Alexandra, Lambris, John D., Chavakis, Triantafyllos, Holdt, Lesca, Kind, Alexander, Guethoff, Sonja, and Mayr, Tanja
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HEART transplantation ,SWINE ,ENZYME inhibitors ,IMMUNOHISTOCHEMISTRY ,HUMAN anatomy - Abstract
Background The complement system plays a crucial role in acute xenogeneic reactions after cardiac transplantation. We used an ex vivo perfusion model to investigate the effect of Cp40, a compstatin analog and potent inhibitor of complement at the level of C3. Methods Fifteen wild-type pig hearts were explanted, cardiopleged, and reperfused ex vivo after 150 minutes of cold ischemia. Hearts were challenged in a biventricular working heart mode to evaluate cardiac perfusion and function. In the treatment group (n=5), the complement cascade was blocked at the level of C3 using Cp40, using diluted human blood. Untreated human and porcine blood was used for controls. Results Throughout the perfusion, C3 activation was inhibited when Cp40 was used (mean of all time points: 1.11 ± 0.34% vs 3.12 ± 0.48% control activation; P<.01). Compared to xenoperfused controls, the cardiac index improved significantly in the treated group (6.5 ± 4.2 vs 3.5 ± 4.8 mL/min/g; P=.03, 180 minutes perfusion), while the concentration of lactate dehydrogenase as a maker for cell degradation was reduced in the perfusate (583 ± 187 U/mL vs 2108 ± 1145 U/mL, P=.02). Histological examination revealed less hemorrhage and edema, and immunohistochemistry confirmed less complement fragment deposition than in untreated xenoperfused controls. Conclusions Cp40 efficiently prevents C3 activation of the complement system, resulting in reduced cell damage and preserved function in wild-type porcine hearts xenoperfused ex vivo. We suggest that this compstatin analog, which blocks all main pathways of complement activation, could be a beneficial perioperative treatment in preclinical and in future clinical xenotransplantation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
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