Article

Rag2−/− γ-chain−/− mice as hosts for human vessel transplantation and allogeneic human leukocyte reconstitution

Department of Cardiac Surgery, Friedrich-Alexander University, Erlangen-Nürnberg, Krankenhausstrasse 12, 91054 Erlangen, Germany.
Transplant Immunology (Impact Factor: 1.46). 05/2010; 23(1-2):59-64. DOI: 10.1016/j.trim.2010.04.003
Source: PubMed

ABSTRACT

Rodent models are a very helpful tool to investigate immunological mechanisms in allograft rejection. The aim of this study was to compare two different immunodeficient recipients in a humanized mouse model of arterial xenotransplantation in terms of reconstitution of the human immune system and rejection of the arterial graft.
Side branches of human mammary artery were transplanted as infrarenal aortic interposition grafts into C.B-17-SCID beige and C57BL/6-Rag2(-/-)gammac(-/-) recipients. 7days after surgery mice were reconstituted with 5x10(7) human peripheral blood mononuclear cells (hu PBMCs) and 30days after reconstitution mice were sacrificed and histologic analysis was performed. Peripheral blood and splenocytes were investigated by FACS and ELISA analysis to ensure engraftment of human CD45(+) cells.
Transplant arteriosclerosis developed in non-PBMC-reconstituted C.B-17-SCID beige mice (intimal proliferation: 36.31+/-4.37%), but significantly less in C57BL/6-Rag2(-/-) gammac(-/-) recipients (intimal proliferation: 12.26+/-5.21%). After reconstitution with 5x10(7) unfractionated human PBMCs both mouse strains showed intima proliferation 30days after reconstitution (C.B-17-SCID beige: 28.49+/-7.95% and C57BL/6-Rag2(-/-) gammac(-/-): 44.58+/-11.08%). Whereas only very few human CD45(+) cells were found in mouse blood and spleen of C.B-17-SCID beige mice, C57BL/6-Rag2(-/-) gammac(-/-) mice revealed a reliable reconstitution. In addition, levels of human IgG and IgM within the peripheral blood were markedly higher in C57BL/6-Rag2(-/-) gammac(-/-) recipients.
In this study we can show, that the use of C57BL/6-Rag2(-/-) gammac(-/-) mice may be advantageous compared to C.B-17-SCID beige recipients in a humanized mouse model of vessel transplantation.

Download full-text

Full-text

Available from: Stephan M Ensminger, Mar 03, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Perioperative nonimmune injuries to an allograft can decrease graft survival. We have developed a model for studying this process using human materials. Human artery segments were transplanted as infrarenal aortic interposition grafts into an immunodeficient mouse host, allowed to "heal in" for 30 days, and then retransplanted into a second mouse host. To induce a reperfusion injury, the healed-in artery segments were incubated for 3 hours under hypoxic conditions ex vivo before retransplantation. To induce immunologic rejection, the animals receiving the retransplanted artery segment were adoptively transferred with human peripheral blood mononuclear cells or purified T cells from a donor allogeneic to the artery 1 week before surgery. To compare rejection of injured versus healthy tissues, these manipulations were combined. Results were analyzed ex vivo by histology, morphometry, immunohistochemistry, and mRNA quantitation or in vivo by ultrasound. Our results showed that reperfusion injury, which otherwise heals with minimal sequelae, intensifies the degree of allogeneic T cell-mediated injury to human artery segments. We developed a new human-mouse chimeric model demonstrating interactions of reperfusion injury and alloimmunity using human cells and tissues that may be adapted to study other forms of nonimmune injury and other types of adaptive immune responses.
    Full-text · Article · Nov 2011 · Arteriosclerosis Thrombosis and Vascular Biology
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Characteristics of vascular prostheses are similar to the natural vessels and it has high histocompatibility after transplantation. But endothelial regeneration is the key for vascular prosthesis unblocked eternally. OBJECTIVE: To investigate the histocompatibility of a novel small-diameter bioartificial vascular graft at different periods postoperatively and the histopathologic changes following intimal regeneration of the vessel wall. METHODS: A dog model of artificial vascular grafts implanted end-to-end by a continuous suture in the common carotid artery was established. RESULTS AND CONCLUSION: Light microscope results showed that at week 12 after graft, endothelial cells were sparsely distributed throughout the neointima surface near the stoma; at month 6 after graft, endothelial cells were presented on the whole surface of the patent graft lumen; 1.5 years after graft, lumens of graft vessels were unobstructed, and parts of endomembrane tissues were found chronic inflammation. Electron microscope results showed that at week 12 after graft, new vascular endothelial cells were in fusiform shape and arranged regularly; besides, the endothelial cells spread from the stoma to the middle of the graft vessel. After graft for 6 months, the endothelial cells spread from the stoma to the middle of the graft vessel. Endothelial cell colony in the middle of the graft vessel showed leaping and flake-like growth, and the cells were arranged more compactly; moreover, their shapes were more like the endothelial cells of mature vessels. After graft for 1.5 years, the whole vessel wall was covered by tightly arranged endothelial cells, and parts of endomembrane tissues revealed chronic inflammation. These findings suggest that the novel small-diameter bioartificial vascular graft has many advantages, for example, the newborn intima forms early and completely, and endangium can be well reconstructed; in addition, it has good biocompatibility and stability.
    No preview · Article · Jan 2012
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent findings emphasized an important role of human cytomegalovirus (HCMV) infection in the development of transplant arteriosclerosis. Therefore, the aim of this study was to develop a human peripheral blood lymphocyte (hu-PBL)/Rag-2(-/-) γc(-/-) mouse-xenograft-model to investigate both immunological as well as viral effector mechanisms in the progression of transplant arteriosclerosis. For this, sidebranches from the internal mammary artery were recovered during coronary artery bypass graft surgery, tissue-typed and infected with HCMV. Then, size-matched sidebranches were implanted into the infrarenal aorta of Rag-2(-/-) γc(-/-) mice. The animals were reconstituted with human peripheral blood mononuclear cells (PBMCs) 7 days after transplantation. HCMV-infection was confirmed by Taqman-PCR and immunofluorescence analyses. Arterial grafts were analyzed by histology on day 40 after transplantation. PBMC-reconstituted Rag-2(-/-) γc(-/-) animals showed splenic chimerism levels ranging from 1-16% human cells. After reconstitution, Rag-2(-/-) γc(-/-) mice developed human leukocyte infiltrates in their grafts and vascular lesions that were significantly elevated after infection. Cellular infiltration revealed significantly increased ICAM-1 and PDGF-R-β expression after HCMV-infection of the graft. Arterial grafts from unreconstituted Rag-2(-/-) γc(-/-) recipients showed no vascular lesions. These data demonstrate a causative relationship between HCMV-infection as an isolated risk factor and the development of transplant-arteriosclerosis in a humanized mouse arterial-transplant-model possibly by elevated ICAM-1 and PDGF-R-β expression.
    Full-text · Article · Mar 2012 · American Journal of Transplantation
Show more