RELATIONSHIP BETWEEN DONOR RENAL INTERSTITIAL SURFACE AND POSTTRANSPLANT FUNCTION

Forty-three biopsies were performed between 30 and 60 min after reperf usion. Patients (22 males/21 females, mean age 41 +/- 12 years, mean d onor age 32 +/- 14 years) were treated either with antilymphocytic glo bulin, cyclosporin, and prednisolone (24 cases), or OKT3, cyclosporin, and prednisolone (19 cases). Ten patients had delayed post-transplant renal function (DPRF), defined as haemodialysis requirements after su rgery, and seven patients had acute rejection 11 +/- 16 days post-tran splant. Kidneys were perfused with a hypertonic solution containing ma nnitol. All patients were followed up for at least 30 months. During f ollow-up, five patients lost their grafts due chronic rejection, two p atients due to non-compliance and one due to recurrence of focal segme ntal glomerulosclerosis. One patient died from heart infarction. Biops ies were stained with H&E, Masson's trichrome, periodic acid-Schiff (P AS) and silver methenamine. Interstitial fibrosis, interstitial oedema , tubular vacuolization, and peritubular capillary oedema were measure d using a semiquantitative scale. Five 400 x magnification micrographs of cortical interstitium from silver-methenamine-stained sections wer e used to measure percentage of interstitial surface with a morphomete r. Interstitial surface was 18.7 +/- 6.2% (range 3.2-35.3%). A positiv e correlation was found between interstitial surface and donor age (r = 0.469, P = 0.0015). No relationship was found between warm and cold ischaemia times and tubular vacuolization or peritubular capillary oed ema. Patients with DPRF had a significantly increased interstitial sur face (23 +/- 8%) when compared with patients without DPRF (17 +/- 5%), (P = 0.014). There was a positive relationship between interstitial s urface and number of days required to achieve a plasma creatinine of 3 00 mumol/l after surgery, this fitted an exponential curve (r = 0.578, P = 0.0012). Patients who had an episode of acute rejection were not included in this calculation. A positive correlation was also found be tween interstitial surface and plasma creatinine at 12 months (r = 0.6 92, P = 0.0001), 18 months (r = 0.713, P = 0.0001), and 24 months (r = 0.586, P = 0.0023) after surgery. Patients who lost their grafts duri ng follow-up were not included in this calculation. The relationship b etween interstitial surface and plasma creatinine 30 months after tran splantation was not significant. There was no relation between tubular vacuolization or peritubular capillary oedema and number of days requ ired to achieve a plasma creatinine of 300 mumol/l or plasma creatinin e 12, 18, 24, and 30 months after transplantation. We conclude that as sessment of donor renal biopsies may help to predict post-transplant r enal function. The increase of interstitial surface due to pre-existin g fibrosis is associated with poor post-transplant graft performance.