Beyond operational tolerance: effect of ischemic injury on development of chronic damage in renal grafts.
BACKGROUND
The induction of operational tolerance is the holy grail of clinical transplantation. However, in animal models with operational tolerance, long- term grafts still develop chronic damage. The elucidation of the impact of allogenic versus nonallogeneic factors in such a model is important. This study examined the effect of a clinically relevant combination of warm ischemia and cold preservation in the absence of allogeneic response (isografts) and in the context of operational tolerance.


METHODS
Dark Agouti (DA) rat kidneys were transplanted into DA recipients (isografts) or Albino Surgery recipients (allografts) tolerized by two transfusions of DA blood, under cover of cyclosporin A. Grafts were subjected to minimal cold preservation or to 30 mins warm ischemia followed by 24 hrs cold preservation.


RESULTS
After an initial peak of renal dysfunction, serum creatinine concentration returned to normal in isografts and nonischemic allografts, but remained significantly elevated in ischemic allografts (P<0.0002) throughout 6 months follow-up. Both allograft groups developed proteinuria. At 6 months, ischemic isografts and nonischemic allografts demonstrated very mild tubular atrophy and interstitial fibrosis. Tubulointerstitial injury was significantly more severe in ischemic allografts (P<0.01 vs. nonischemic allografts) and was associated with increased infiltrating monocyte/macrophages and NK cells (P<0.05). Moderate glomerulosclerosis was a feature of both allograft groups (P<0.05).


CONCLUSIONS
The modified allogeneic response in operationally tolerant recipients acts in synergy with ischemia/reperfusion injury in the development of chronic damage. Strategies to limit or modify the initial ischemia/reperfusion injury may ameliorate chronic tubulointerstitial damage. Progressive glomerular damage and proteinuria in allografts may require other pharmacological intervention.
Coulson
Mark T
MT
Department of Medicine, Monash University, Central and Eastern Clinical School, Alfred Hospital, Prahran, Victoria, Australia.
Jablonski
Paula
P
Howden
Brian O
BO
Thomson
Napier M
NM
Stein
Alicia N
AN
D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D003404:Creatinine / Q000097:blood; D015925:Cryopreservation; D006084:Graft Rejection; D006085:Graft Survival; D007150:Immunohistochemistry; D007511:Ischemia; D007668:Kidney / Q000473:pathology; D007674:Kidney Diseases / Q000209:etiology; D016030:Kidney Transplantation / Q000009:adverse effects* / Q000379:methods*; D008264:Macrophages / Q000378:metabolism; D009926:Organ Preservation; D019188:Organ Preservation Solutions; D051381:Rats; D015427:Reperfusion Injury; D013997:Time Factors
D000911:Antibodies, Monoclonal; D019188:Organ Preservation Solutions; D003404:Creatinine