Large Animal Models of Vascularized Composite Allotransplantation: A Review of Immune Strategies to Improve Allograft Outcomes.
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ABSTRACT:
SUBMITTER: Matar AJ
PROVIDER: S-EPMC8278218 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Vascularized composite allograft (VCA) transplantation can restore form and function following severe craniofacial injuries, extremity amputations or massive tissue loss. The induction of transplant tolerance would eliminate the need for long-term immunosuppression, realigning the risk-benefit ratio for these life-enhancing procedures. Skin, a critical component of VCA, has consistently presented the most stringent challenge to transplant tolerance. Here, we demonstrate, in a clinically relevant miniature swine model, induction of immunologic tolerance of VCAs across MHC barriers by induction of stable hematopoietic mixed chimerism. Recipient conditioning consisted of T cell depletion with CD3-immunotoxin, and 100 cGy total body irradiation prior to hematopoietic cell transplantation (HCT) and a 45-day course of cyclosporine A. VCA transplantation was performed either simultaneously to induction of mixed chimerism or into established mixed chimeras 85-150 days later. Following withdrawal of immunosuppression both VCAs transplanted into stable chimeras (n=4), and those transplanted at the time of HCT (n=2) accepted all components, including skin, without evidence of rejection to the experimental end point 115-504 days posttransplant. These data demonstrate that tolerance across MHC mismatches can be induced in a clinically relevant VCA model, providing proof of concept for long-term immunosuppression-free survival.
| S-EPMC3971524 | biostudies-literature
Project description:Vascularized composite allografts (VCAs) can restore fully functional anatomic units in patients with limb amputations or severe facial tissue loss. However, acute rejection of the skin is frequently observed and underscores the importance of developing tolerance induction protocols. In this study, we have characterized the skin immune system in VCAs. We demonstrate infiltration of recipient leukocytes, regardless of rejection status, and in tolerant mixed hematopoietic chimeras, the co-existence of these cells with donor leukocytes in the absence of rejection. Here we characterize the dermal T cell and epidermal Langerhans cell components of the skin immune system in our porcine model of VCA tolerance, and the kinetics of cutaneous chimerism in both of these populations in VCAs transplanted to tolerant and nontolerant recipients, as well as in host skin. Furthermore, in biopsies from the first patient to receive a hand transplant in our program, we demonstrate the presence of recipient T cells in the skin of the transplanted limb in the absence of clinical or histological evidence of rejection.
| S-EPMC7854956 | biostudies-literature
Project description:Vascular composite allotransplantation (VCA) is a field under research and has emerged as an alternative option for the repair of severe disfiguring defects that result from infections or traumatic amputation in a selected group of patients. VCA is performed in centers with appropriate expertise, experience and adequate resources to effectively manage the complexity and complications of this treatment. Lifelong immunosuppressive therapy, immunosuppression associated complications, and the effects of the host immune response in the graft are major concerns in VCA. VCA is considered a quality of life transplant and the risk-benefit ratio is dissimilar to life saving transplants. Belatacept seems a promising drug that prolongs patient and graft survival in kidney transplantation and it could also be an alternative approach to VCA immunosuppression. In this review, we are summarizing current literature about the role of costimulation blockade, with a focus on belatacept in VCA.
| S-EPMC7527523 | biostudies-literature
Project description:BackgroundKidney dysfunction is a major complication after nonrenal solid organ transplants. Transplantation of vascularized composite allografts (VCA) has yielded successful midterm outcomes despite high rates of acute rejection and greater requirements of immunosuppression. Whether this translates in higher risks of kidney complications is unknown.MethodsNinety-nine recipients of facial or extremity transplants from the Brigham and Women's Hospital (BWH) and the International Registry on Hand and Composite Tissue Transplantation (IR) were reviewed. We assessed immunosuppression, markers of renal function over time, as well as pretransplant and posttransplant renal risk factors.ResultsData were obtained from 10 patients from BWH (age at transplant, 42.5 ± 13.8 years) and 89 patients (37.8 ± 11.5 years) from IR. A significant rise in creatinine levels (BWH, P = 0.0195; IR, P < 0.0001) and drop in estimated glomerular filtration rate (GFR) within the first year posttransplant was observed. The BWH and IR patients lost a mean of 22 mL/min GFR and 60 mL/min estimated GFR in the first year, respectively. This decrease occurred mostly in the first 6 months posttransplant (BWH). Pretransplant creatinine levels were not restored in either cohort. A mixed linear model identified multiple variables correlating with renal dysfunction, particularly tacrolimus trough levels.ConclusionsKidney dysfunction represents a major complication posttransplantation in VCA recipients early on. Strategies to mitigate this complication, such as reducing calcineurin inhibitor trough levels or using alternative immunosuppressive agents, may improve long-term patient outcomes. Standardizing laboratory and data collection of kidney parameters and risk factors in VCA patients will be critical for better understanding of this complication.
| S-EPMC6056276 | biostudies-literature
Project description:Facial vascularized composite allotransplantation (fVCA) represents a valuable surgical option for reconstruction of the most devastating facial defects. There is a mounting body of evidence suggesting that healthcare disparities exist for a variety of other surgical and nonsurgical procedures. We aimed to investigate the potential existence of racial and ethnic disparities in the field of fVCA.MethodsA comprehensive literature review was conducted by the authors of this review on PubMed/MEDLINE, and Embase databases from database inception to December 1, 2022 for studies published in the English and French languages. The search terms were (1) "face" OR "facial" AND (2) "transplant" OR "VCA" OR "vascularized composite allotransplantation" OR "vascularized composite allograft" OR "graft."ResultsUpon assessment of the racial and ethnic demographics of the 47 global cases of fVCA between 2005 and 2020, 36 were White, 10 were Asian, and one was Black. Sixteen of the 17 fVCA procedures performed in the United States involved White patients. The other patient self-identified as Black, equaling 6% of all US fVCA recipients.ConclusionOur analysis showed that the ethnic and racial distribution of fVCA has not proportionally reflected the racial and ethnic demographics of the general US population, underscoring the risk of such healthcare imbalances. Although large-scale studies are needed before drawing definitive conclusions, leaders in the field should take preventive steps to avoid potential disparities. Further investigations into the factors that facilitate or prohibit access to fVCA referral and surgery will be necessary moving forward.
| S-EPMC10419650 | biostudies-literature
Project description:Purpose: to explore the function and mechanism of acute rejection in vascularized composite allotransplantation Method: tRF & tiRNA profiles of acute rejection in vascularized composite allotransplantation were generated by deep sequencing, using Illumina NextSeq 500. qRT–PCR validation was performed using SYBR Green assays. Results:Sequencing was used to screen expression profiles and predict target genes. Compared with the control group, there were significant differences in the expression levels of 16 tRFs & tiRNAs, including 5 up-regulated target genes and 11 down-regulated target genes. Bioinformatics analysis and RT-qPCR revealed potential up regulation of tRFs & tiRNAs(tiRNA-1-33-Gly-GCC-1, tiRNA-1-34-Glu-CTC-1, tRF-1-32-Gly-GCC-2-M2) and down regulation of tRFs & tiRNAs (tRF-59:75-Gln-CTG-2-M2, tRF-59:76-Val-AAC-1-M2). Conclusion: In conclusion, it is speculated that tiRNA-1-34-Glu-CTC-1 plays an important role in VCA induced acute rejection by regulating CACNA1D gene in MAPK signaling pathway. This provides a new insight into the mechanism and therapeutic targets of acute rejection.
2022-07-20 | GSE190008 | GEO
Project description:Despite recent progress in vascularized composite allotransplantation (VCA), limitations including complex, high dose immunosuppression regimens, lifelong risk of toxicity from immunosuppressants, acute and most critically chronic graft rejection, and suboptimal nerve regeneration remain particularly challenging obstacles restricting clinical progress. When properly configured, customized, and implemented, biomaterials derived from the extracellular matrix (ECM) retain bioactive molecules and immunomodulatory properties that can promote stem cell migration, proliferation and differentiation, and constructive functional tissue remodeling. The present paper reviews the emerging implications of ECM-based technologies in VCA, including local immunomodulation, tissue repair, nerve regeneration, minimally invasive graft targeted drug delivery, stem cell transplantation, and other donor graft manipulation.
| S-EPMC4709778 | biostudies-literature
Project description:BackgroundChronic rejection remains the Achilles heel in vascularized composite allotransplantation. Animal models to specifically study chronic rejection in vascularized composite allotransplantation do not exist so far. However, there are established rat models to study chronic rejection in solid organ transplantation such as allogeneic transplantation between the rat strains Lewis and Fischer344. Thus, we initiated this study to investigate the applicability of hindlimb transplantation between these strains to imitate chronic rejection in vascularized composite allotransplantation and identify potential markers.MethodsAllogeneic hindlimb transplantation were performed between Lewis (recipient) and Fischer344 (donor) rats with either constant immunosuppression or a high dose immunosuppressive bolus only in case of acute skin rejections. Histology, immunohistochemistry, microarray and qPCR analysis were used to detect changes in skin and muscle at postoperative day 100.ResultsWe were able to demonstrate significant intimal proliferation, infiltration of CD68 and CD4 positive cells, up-regulation of inflammatory cytokines and initiation of muscular fibrosis in the chronic rejection group. Microarray analysis and subsequent qPCR identified CXC ligands 9-11 as potential markers of chronic rejection.ConclusionsThe Fischer344 to Lewis hindlimb transplantation model may represent a new option to study chronic rejection in vascularized composite allotransplantation in an experimental setting. CXC ligands 9-11 deserve further research to investigate their role as chronic rejection markers.
| S-EPMC7319338 | biostudies-literature
Project description:Illumina tRFs & tiRNAs-seq analysis was used to characterize the whole transcriptomes of acute rejection caused by vascularized composite allotransplantation (VCA). tRFs & tiRNAs-seq information for muscle samples with VCA was obtained and compared with similar information for same age- and sex-matched healthy control subjects. The expression of 16 tRFs and tiRNAs, including 5 up-regulated target genes and 11 down-regulated target genes, were significantly different. According to bioinformatics analysis and reverse transcription quantitative polymerase chain reaction, we speculate that tiRNA-1-34-Glu-CTC-1 plays an important role in VCA-induced acute rejection by regulating the CACNA1D gene in the MAPK signaling pathway The findings provide the whole-transcriptome signatures of acute rejection for VCA, allowing further exploration of gene expression patterns/signatures associated with the various clinical symptoms of acute rejection for VCA.
| S-EPMC9452673 | biostudies-literature
Project description:For individuals who sustain devastating composite tissue loss, vascularized composite allotransplantation (VCA; e.g., hand and face transplantation) has the potential to restore appearance and function of the damaged tissues. As with solid organ transplantation, however, rejection must be controlled by multidrug systemic immunosuppression with substantial side effects. As an alternative therapeutic approach inspired by natural mechanisms the body uses to control inflammation, we developed a system to enrich regulatory T cells (Tregs) in an allograft. Microparticles were engineered to sustainably release TGF-β1, IL-2, and rapamycin, to induce Treg differentiation from naïve T cells. In a rat hindlimb VCA model, local administration of this Treg-inducing system, referred to as TRI-MP, prolonged allograft survival indefinitely without long-term systemic immunosuppression. TRI-MP treatment reduced expression of inflammatory mediators and enhanced expression of Treg-associated cytokines in allograft tissue. TRI-MP also enriched Treg and reduced inflammatory Th1 populations in allograft draining lymph nodes. This local immunotherapy imparted systemic donor-specific tolerance in otherwise immunocompetent rats, as evidenced by acceptance of secondary skin grafts from the hindlimb donor strain and rejection of skin grafts from a third-party donor strain. Ultimately, this therapeutic approach may reduce, or even eliminate, the need for systemic immunosuppression in VCA or solid organ transplantation.
| S-EPMC6925993 | biostudies-literature