1
|
Thompson CP, Jagdale A, Walcott G, Iwase H, Foote JB, Cron RQ, Hara H, Cleveland DC, Cooper DKC. A perspective on the potential detrimental role of inflammation in pig orthotopic heart xenotransplantation. Xenotransplantation 2021; 28:e12687. [PMID: 33786912 DOI: 10.1111/xen.12687] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/26/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023]
Abstract
There is a critical shortage of deceased human donor organs for transplantation. The need is perhaps most acute in neonates and infants with life-threatening congenital heart disease, in whom mechanical support devices are largely unsuccessful. If orthotopic (life-supporting) heart transplantation (OHTx) were consistently successful in the genetically engineered pig-to-nonhuman primate (NHP) model, a clinical trial of bridging with a pig heart in such patients might be justified. However, the results of pig OHTx in NHPs have been mixed and largely poor. We hypothesise that a factor is the detrimental effects of the inflammatory response that is known to develop (a) during any surgical procedure that requires cardiopulmonary bypass, and (b) immediately after an NHP recipient is exposed to a pig xenograft. We suggest that the combination of these two inflammatory responses has a direct detrimental effect on pig heart graft function, but also, and possibly of more importance, on recipient baboon pulmonary function, which further impacts survival of the pig heart graft. In addition, the inflammatory response almost certainly adversely impacts the immune response to the graft. If our hypothesis is correct, the potential steps that could be taken to reduce the inflammatory response or its effects (with varying degrees of efficacy) include (a) white blood cell filtration, (b) complement depletion or inactivation, (c) immunosuppressive therapy, (d) high-dose corticosteroid therapy, (e) cytokine/chemokine-targeted therapy, (f) ultrafiltration or CytoSorb hemoperfusion, (g) reduction in the levels of endogenous catecholamines, (h) triiodothyronine therapy and (i) genetic engineering of the organ-source pig. Prevention of the inflammatory response, or attenuation of its effects, by judicious anti-inflammatory therapy may contribute not only to early survival of the recipient of a genetically engineered pig OHTx, but also to improved long-term pig heart graft survival. This would open the possibility of initiating a clinical trial of genetically engineered pig OHTx as a bridge to allotransplantation.
Collapse
Affiliation(s)
- Charles P Thompson
- Xenotransplantation Program, Division of Transplantation, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Abhijit Jagdale
- Xenotransplantation Program, Division of Transplantation, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Gregory Walcott
- Department of Medicine/Cardiovascular Diseases, the University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hayato Iwase
- Xenotransplantation Program, Division of Transplantation, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jeremy B Foote
- Department of Microbiology and Animal Resources Program, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Randall Q Cron
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Division of Transplantation, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David C Cleveland
- Division of Cardiothoracic Surgery, Children's Hospital of Alabama, and Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David K C Cooper
- Xenotransplantation Program, Division of Transplantation, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| |
Collapse
|
2
|
Li T, Jiang H, Liu H, Cooper DKC, Wang Y. Extracellular histones and xenotransplantation. Xenotransplantation 2020; 27:e12618. [PMID: 32940936 DOI: 10.1111/xen.12618] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/24/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Tao Li
- Department of Organ Transplantation The Second Affiliated Hospital of Hainan Medical University Haikou Hainan China
- The Transplantation Insititute of Hainan Medical University Haikou Hainan China
| | - Hongtao Jiang
- Department of Organ Transplantation The Second Affiliated Hospital of Hainan Medical University Haikou Hainan China
- The Transplantation Insititute of Hainan Medical University Haikou Hainan China
| | - Houqin Liu
- Department of Organ Transplantation The Second Affiliated Hospital of Hainan Medical University Haikou Hainan China
- The Transplantation Insititute of Hainan Medical University Haikou Hainan China
| | - David K. C. Cooper
- Xenotransplantation Program Department of Surgery University of Alabama at Birmingham Birmingham AL USA
| | - Yi Wang
- Department of Organ Transplantation The Second Affiliated Hospital of Hainan Medical University Haikou Hainan China
- The Transplantation Insititute of Hainan Medical University Haikou Hainan China
| |
Collapse
|
3
|
Abstract
There is a well-known worldwide shortage of deceased human donor organs for clinical transplantation. The transplantation of organs from genetically engineered pigs may prove an alternative solution. In the past 5 years, there have been sequential advances that have significantly increased pig graft survival in nonhuman primates. This progress has been associated with (1) the availability of increasingly sophisticated genetically engineered pigs; (2) the introduction of novel immunosuppressive agents, particularly those that block the second T-cell signal (costimulation blockade); (3) a better understanding of the inflammatory response to pig xenografts; and (4) increasing experience in the management of nonhuman primates with pig organ or cell grafts. The range of investigations required in experimental studies has increased. The standard immunologic assays are still carried out, but increasingly investigations aimed toward other pathobiologic barriers (e.g., coagulation dysregulation and inflammation) have become more important in determining injury to the graft.Now that prolonged graft survival, extending to months or even years, is increasingly being obtained, the function of the grafts can be more reliably assessed. If the source pigs are bred and housed under biosecure isolation conditions, and weaned early from the sow, most microorganisms can be eradicated from the herd. The potential risk of porcine endogenous retrovirus (PERV) infection remains unknown, but is probably small. Attention is being directed toward the selection of patients for the first clinical trials of xenotransplantation.
Collapse
Affiliation(s)
- David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|
4
|
Evidence for the important role of inflammation in xenotransplantation. JOURNAL OF INFLAMMATION-LONDON 2019; 16:10. [PMID: 31148951 PMCID: PMC6537172 DOI: 10.1186/s12950-019-0213-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/02/2019] [Indexed: 12/17/2022]
Abstract
There is increasing evidence of a sustained state of systemic inflammation after pig-to-nonhuman primate (NHP) xenotransplantation (that has been termed systemic inflammation in xenograft recipients [SIXR]). Increases in inflammatory markers, e.g., C-reactive protein, histones, serum amyloid A, D-dimer, cytokines, chemokines, and a decrease in free triiodothyronine, have been demonstrated in the recipient NHPs. The complex interactions between inflammation, coagulation, and the immune response are well-recognized, but the role of inflammation in xenograft recipients is not fully understood. The evidence suggests that inflammation can promote the activation of coagulation and the adaptive immune response, but the exact mechanisms remain uncertain. If prolonged xenograft survival is to be achieved, anti-inflammatory strategies (e.g., the administration of anti-inflammatory agents, and/or the generation of genetically-engineered organ-source pigs that are protected from the effect of inflammation) may be necessary to prevent, control, or negate the effect of the systemic inflammation that develops in xenograft recipients. This may allow for a reduction in the intensity of exogenous immunosuppressive therapy. If immunological tolerance to a xenograft is to be obtained, then control of inflammation may be essential.
Collapse
|
5
|
Zhang G, Hara H, Yamamoto T, Li Q, Jagdale A, Li Y, Cooper DKC, Iwase H. Serum amyloid a as an indicator of impending xenograft failure: Experimental studies. Int J Surg 2018; 60:283-290. [PMID: 30521954 PMCID: PMC6310230 DOI: 10.1016/j.ijsu.2018.11.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 11/30/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND There is well-documented systemic inflammatory response in xenograft recipients to the presence of a pig graft. Serum amyloid A (SAA) is an inflammatory marker that is elevated in various pathological states. The assay used to measure it is (i) simple, (ii) relatively inexpensive, and (iii) provides an answer within minutes. METHOD The levels of SAA (n = 11) and C-reactive protein (C-RP) (n = 8) were measured retrospectively in the serum of baboons with pig kidney transplants, who received therapy with an IL-6R inhibitor and a TNF-α antagonist. Immunohistochemistry (IHC) was used to identify amyloid A and C-RP expression in the native livers and deposition in the pig kidney grafts. RESULTS One kidney graft underwent hyperacute rejection, 6 (55%) underwent acute antibody-mediated rejection, 3 baboons (27%) were euthanized for serious systemic infections, and one was euthanized for acute gastric dilatation. The SAA increased temporarily after kidney transplantation, and increased again by the day of euthanasia, indicating moderate (n = 3) or significant (severe) (n = 8) inflammation. In contrast, as the baboons were receiving tocilizumab, C-RP did not increase. There was greater expression of amyloid A in baboon livers (by IHC) than of C-RP (mean OD 53 vs 1, p < 0.01), and greater deposition of amyloid A than C-RP in the pig kidney grafts (mean OD 24 vs 2, p < 0.001). Plasma fibrinogen negatively correlated with the expression of amyloid A in the liver (r = -0.72, p < 0.05). The results of the SAA assay correlated with amyloid A expression in the liver and deposition in the kidney grafts. CONCLUSIONS SAA is a sensitive, but non-specific, marker for inflammation in baboons with pig kidney grafts, and is not affected by therapy that suppresses the response of C-RP. The SAA assay is a rapid, reliable, and relatively inexpensive method of following the inflammatory state of baboons with pig xenografts.
Collapse
Affiliation(s)
- Guoqiang Zhang
- Department of General Surgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China; Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Takayuki Yamamoto
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Qi Li
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Abhijit Jagdale
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yong Li
- Department of General Surgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, China.
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hayato Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|