Natural history of kidney graft survival, hypertrophy, and vascular function in end-stage renal disease type 1 diabetic kidney-transplanted patients: beneficial impact of pancreas and successful islet cotransplantation

OBJECTIVE: Diabetes, hypertension, infections, and nephrotoxicity of certain immunosuppressive drugs (i.e., calcineurin inhibitors) can reduce functional survival of the kidney graft. Our aim was to evaluate survival, hypertrophy, and vascular function of the kidney graft in end-stage renal disease (ESRD) type 1 diabetic patients after transplant. RESEARCH DESIGN AND METHODS: The study population consisted of 234 ESRD type 1 diabetic patients who underwent kidney-pancreas (KP; 166 patients), successful kidney-islet (KI-s; 24 patients), and kidney (KD; 44 patients) transplant. Kidney size, graft survival, vascular function, and microalbuminuria were evaluated prospectively yearly for 6 years. Sixty-eight protocol kidney biopsies were performed routinely between 1993 and 1998 cross-sectionally (3.2 +/- 0.3 years from kidney transplant). RESULTS: The KP and KI-s groups had better cumulative kidney graft survival at 6 years than did the KD group (KP: 73%; KI-s: 86%; KD: 42%, P < 0.01). The KP group but not the KI-s/KD groups showed a persistent kidney graft hypertrophy up to 6 years of follow-up. A significant increase in creatinine levels from baseline to year 6 was evident in the KD group (1.58 +/- 0.08 to 2.78 +/- 0.44 mg/dl, P < 0.05) but not in the KP/KI-s groups. The KP/KI-s groups only showed a reduction of renal resistance index from baseline to year 6 (KP at baseline: 0.74 +/- 0.01 to 0.68 +/- 0.01%, P < 0.01; KI-s at baseline: 0.72 +/- 0.02 to 0.69 +/- 0.02%, P < 0.05). At year 6, an increase from baseline in urinary albumin excretion was observed only in the KD group (31.4 +/- 9.0 to 82.9 +/- 33.6 mg/l, P < 0.05). Preliminary data suggested that graft nitric oxide (NO) expression was higher in the KP/KI-s groups than in the KD group (data not shown). CONCLUSIONS: In ESRD type 1 diabetic patients, KP and KI-s compared with KD resulted in enhanced kidney graft survival, hypertrophy, and vascular function