Contribution of native kidney function to total glomerular filtration rate after combined kidney-pancreas transplantation.
BACKGROUND
Combined kidney-pancreas transplantation (CKPT) with its associated euglycemia has been shown to prevent or reduce recurrent diabetic nephropathy in the renal allograft. There has been no evaluation of residual native kidney function after CKPT. The purpose of this study was to determine whether native kidney function may be present in diabetic recipients years after CKPT.


METHODS
Between 1986 and 1992, 37 patients with type 1 insulin-dependent diabetes mellitus with renal failure underwent CKPT. In each case, a single native nephrectomy was performed. We studied 16 patients who had continuing renal and pancreas function more than 4 years after CKPT. Fourteen diabetics with a functioning renal allograft but no pancreas function were used as a control group. Simultaneous renal scans (technetium-99m diethylenetriamine pentaacetic acid) of the native and transplanted kidneys were obtained with a dual-head scintillation camera. Total glomerular filtration rate (GFR) was determined from the rate of clearance of the tracer from the extracellular space measured for 2 hr with an ambulatory renal monitor.


RESULTS
The study groups had similar pretransplant characteristics. At the time of the study, the mean serum creatinine level was not significantly different in the CKPT and control groups (1.7+/-0.7 vs. 1.5+/-0.3 mg/dl, respectively). In the CKPT and control groups, total GFRs were 70.1+/-33 vs. 72.1+/-16.5 ml/min (NS), allograft GFRs were 63+/-34.2 vs. 70.4+/-16 ml/min (NS), and native kidney GFRs were 7.1+/-7.2 vs. 1.7+/-1.9 ml/min (P < 0.05), respectively. In both groups, there was a significant correlation between total GFR and allograft GFR (P < 0.001), but not between total GFR and native kidney GFR. Significant single native kidney GFR (more than 8 ml/min) was found in 7/16 (44%) patients in the CKPT group, but in none of the controls.


CONCLUSIONS
These results suggest that residual native kidney function can be present and contribute moderately to total GFR after CKPT. Euglycemia after CKPT may have a protective role in native kidneys.
Pascual
M
M
Transplantation Unit, Massachusetts General Hospital, Boston 02114, USA.
Rabito
C A
CA
Tolkoff-Rubin
N
N
Auchincloss
H
H
Farrell
M L
ML
Delmonico
F L
FL
Cosimi
A B
AB
D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000601:surgery; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000502:physiology*; D016030:Kidney Transplantation / Q000502:physiology*; D008297:Male; D016035:Pancreas Transplantation / Q000502:physiology*