Recipient hypertension potentiates chronic functional and structural injury of rat renal allografts.
BACKGROUND
Systemic hypertension affects many allograft recipients, is an important risk factor for chronic graft dysfunction, and is linked to reduced graft survival. The condition may up-regulate the expression of inflammatory host cells and their products. These, in turn, may significantly injure vascular endothelium and other components of allografted kidneys.


METHODS
Lewis rats received orthotopic F344 renal allografts, a standard model of chronic rejection. Renovascular hypertension was produced by placing a silver clip (0.25 mm) on the renal artery of the retained contralateral native kidney 4 weeks after transplantation. Sham-clipped rats served as normotensive controls. Four recipient groups (Gp) were studied: Gp 1, rats with an allograft plus a clipped native kidney; Gp 2, those with an allograft and a sham-clipped native kidney; Gp 3, isografted animals with a clipped native kidney; and Gp 4, those bearing an isograft and a sham-clipped native kidney. Systolic blood pressure and proteinuria were measured every 2 weeks for 24 weeks. Grafts were assessed serially for morphologic and immunohistologic changes.


RESULTS
Systemic blood pressure rose to hypertensive levels in Gps 1 and 3 within a week of clipping but never increased in Gps 2 and 4. Proteinuria developed in hypertensive animals but remained at baseline in normotensive controls. Intimal thickening of allograft arteries progressed to luminal obliteration with extensive perivascular and interstitial fibrosis by 24 weeks. In contrast, vascular changes in isografts of hypertensive hosts were restricted to medial hypertrophy. Tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, platelet derived growth factor (PDGF), endothelin, Il-6, major histocompatibility complex (MHC) class II, and B7 were up-regulated in allografts in hypertensive hosts. Vascular deposition of immunoglobulin (IgG) was increased. These changes were markedly less pronounced in Gp 3 isografts and minimal in the kidneys of the normotensive animals of Gps 2 and 4.


CONCLUSIONS
An experimental model is presented that examines the influence of recipient hypertension in the pathogenesis of chronic dysfunction and injury developing in rat renal allografts over time.
Kusaka
Mamoru
M
1Surgical Research Laboratory, Harvard Medical School, Department of Surgery, Brigham and Women's Hospital, Boston, MA 02115, USA.
Mackenzie
Harald S
HS
Ziai
Farzard
F
Hancock
Wayne W
WW
Tilney
Nicholas L
NL
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001794:Blood Pressure / Q000502:physiology*; D004549:Elastin / Q000032:analysis; D006085:Graft Survival / Q000276:immunology / Q000502:physiology*; D006977:Hypertension, Renal / Q000150:complications*; D006984:Hypertrophy; D016030:Kidney Transplantation / Q000473:pathology* / Q000502:physiology*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D017207:Rats, Sprague-Dawley; D014184:Transplantation, Homologous; D014185:Transplantation, Isogeneic / Q000502:physiology
D015415:Biomarkers; D004549:Elastin