Structural and functional correlations in stable renal allografts.
BACKGROUND
Renal functional reserve (RFR) has been proposed as a surrogate marker of renal mass, but its significance in well-functioning renal transplants is controversial. Thus, we used early protocol biopsies to analyze structural and functional correlations in stable grafts.


METHODS
We studied 32 cyclosporine (CsA)-treated stable cadaveric transplants at 5 months. Biopsies were evaluated according to Banff criteria and histomorphometry. Inulin and p-aminohippurate clearances were used to calculate glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). RFR after an amino acid infusion (RFR-AA) and after a combined amino acid and dopamine infusion (RFR-AA-DOPA) was evaluated.


RESULTS
Baseline GFR was 54 +/- 16 mL/min/1.73 m2, and ERPF was 219 +/- 55 mL/min/1.73 m2. RFR-AA was 9% +/- 13%, and RFR-AA-DOPA was 22% +/- 20%. RFR-AA correlated with CsA dose (R = 0.39; P = 0.02), whereas RFR-AA-DOPA correlated with CsA dose (R = 0.36; P = 0.04) and CsA levels (R = 0.40; P = 0.02). The only histological parameter associated with RFR was the presence of arteriolar hyalinosis (AH). Patients showing an AH score of 1 or greater (n = 7) had lower RFR-AA (0% +/- 9% versus 11% +/- 13%; P = 0.02) and lower RFR-AA-DOPA (9% +/- 17% versus 26% +/- 19%; P = 0.03). Multivariate analysis showed that an AH score of 1 or greater, but not CsA dose or levels, was associated with RFR-AA (R = 0.42; P = 0.01). RFR-AA-DOPA was associated with hyaline arteriolar damage (R = 0.43; P = 0.01), as well as CsA levels (R = 0.54; P = 0.006).


CONCLUSIONS
The presence of AH is the only histological parameter associated with impaired RFR in well-functioning grafts.
Nephrology Department, Hospital de Bellvitge, Universitat de Barcelona, L'Hospitalet, Barcelona, Spain. 28383xfo@comb.es
Xavier
X
Fulladosa
Francesc
F
Moreso
Joan
J
Torras
Miquel
M
Hueso
Josep M
JM
Grinyó
Daniel
D
Serón
D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D005260:Female; D005923:Glomerulosclerosis, Focal Segmental / Q000473:pathology*; D006801:Humans; D007668:Kidney / Q000473:pathology*; D007677:Kidney Function Tests; D016030:Kidney Transplantation / Q000473:pathology* / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D014655:Vascular Resistance