Aging and transplant arteriosclerosis in absence of alloreactivity and immunosuppressive drugs in a rat aortic model: recipient age's contribution.
BACKGROUND
Almost half of all transplanted vascularized organ grafts will be lost to transplant arteriosclerosis sometime posttransplantation. Organ shortage for primary transplants and retransplants has led to donor-pool expansion to include elderly donors, knowing that aging per se promotes arteriosclerosis. The current understanding that donor age negatively affects organ and/or patient survival outcome is undermined by variables such as the use of immunosuppressive drugs, their toxicity to the graft, degree of donor-recipient histocompatibility, and the resulting chronic rejection. The purpose of this study was to determine whether the donor's age or recipient's age matters the most in transplant arteriosclerosis in the absence of such variables.


METHODS
A syngeneic combination was used where young (2-month-old) and old (22-month-old) donor aortas were injured to initiate neointimal thickening, then transplanted into age-mismatched recipients for 14, 60, and 90 days and then assessed for neointimal thickening. Base level injury response due ischemia and surgery was evaluated in age-matched and noninjured aortic grafts, respectively.


RESULTS
Young aortas invariably developed thicker neointima when transplanted into old recipients than when transplanted into young ones. Correspondingly, old aortas transplanted in young recipients consistently developed less neointimal thickening than when transplanted into old recipients.


CONCLUSIONS
Our findings strongly suggest that the severity of age-related neointima formation is primarily determined by the recipient's age rather than the donor's age. Therefore, in addition to focusing on donor-specific tolerance induction, strategies aiming at increasing the lifespan of vascularized organ grafts also have to take into consideration the recipient's aging milieu.
Calfa
Marian
M
Department of Surgery and the Vascular Biology Institute, University of Miami, Miami, FL 33136, USA.
Aïtouche
Abdelouahab
A
Vazquez-Padron
Roberto I
RI
Gay-Rabinstein
Carlota
C
Lasko
David
D
Badell
John
J
Farji
Arie
A
El-Haddad
Ahmed
A
Liotta
Carlos
C
Louis
Louis B
LB
Simmonds
Alric
A
Pestana
Ivo A
IA
Pang
Manhui
M
Li
Sen
S
Pham
Si M
SM
D000375:Aging / Q000502:physiology*; D000818:Animals; D001011:Aorta / Q000254:growth & development / Q000473:pathology / Q000637:transplantation*; D001013:Aorta, Thoracic / Q000473:pathology; D001161:Arteriosclerosis / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D006085:Graft Survival; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D051381:Rats; D011916:Rats, Inbred F344; D014184:Transplantation, Homologous / Q000276:immunology / Q000473:pathology*; D014185:Transplantation, Isogeneic; D017539:Tunica Intima / Q000473:pathology
D007166:Immunosuppressive Agents