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Chronic rejection of mouse kidney allografts
1Department of Medicine, Duke Medical Center, Durham, North Carolina, USA. roslyn.mannon@acpub.duke.edu
Background:
Chronic renal allograft rejection is the leading cause of late graft failure. However, its pathogenesis has not been defined.
Methods:
To explore the pathogenesis of chronic rejection, we studied a mouse model of kidney transplantation and examined the effects of altering the expression of donor major histocompatibility complex (MHC) antigens on the development of chronic rejection.
Results:
We found that long-surviving mouse kidney allografts develop pathological abnormalities that resemble chronic rejection in humans. Furthermore, the absence of MHC class I or class II antigens did not prevent the loss of graft function nor alter the pathological characteristics of chronic rejection. Expression of transforming growth factor-beta (TGF-beta), a pleiotropic cytokine suggested to play a role in chronic rejection, was markedly enhanced in control allografts compared with isografts. However, TGF-beta up-regulation was significantly blunted in MHC-deficient grafts. Nonetheless, these differences in TGF-beta expression did not affect the character of chronic rejection, including intrarenal accumulation of collagens.
Conclusions:
Reduced expression of either class I or II direct allorecognition pathways is insufficient to prevent the development of chronic rejection, despite a reduction in the levels of TGF-beta expressed in the allograft. This suggests that the severity of chronic rejection is independent of the level of MHC disparity between donor and recipient and the level of TGF-beta expression within the allograft.
Insights
Chronic renal allograft rejection, a major cause of graft failure, appears independent of major histocompatibility complex (MHC) disparity. Even with reduced TGF-beta, rejection severity remained unchanged in mouse kidney transplants.
Area of Science:
- Transplantation immunology
- Renal pathology
Background:
- Chronic renal allograft rejection is the primary cause of late graft loss.
- The precise pathogenesis of chronic rejection remains incompletely understood.
Purpose of the Study:
- To investigate the pathogenesis of chronic renal allograft rejection.
- To examine the impact of major histocompatibility complex (MHC) antigen expression on chronic rejection development using a mouse kidney transplant model.
Main Methods:
- Utilized a mouse model of kidney transplantation.
- Manipulated donor MHC antigen expression to assess its effect on chronic rejection.
- Analyzed graft function, pathology, and transforming growth factor-beta (TGF-beta) expression.
Main Results:
- Long-term mouse kidney allografts exhibited pathology similar to human chronic rejection.
- Absence of MHC class I or II antigens did not prevent graft dysfunction or alter chronic rejection characteristics.
- TGF-beta expression was elevated in control allografts but blunted in MHC-deficient grafts, without affecting rejection severity or collagen accumulation.
Conclusions:
- Reducing MHC class I or II expression is insufficient to prevent chronic rejection.
- Chronic rejection severity is independent of the degree of MHC disparity and intragraft TGF-beta levels.