Delayed graft function (DGF) is a common complication following renal transplantation. It occurs in 38% - 50% of recipients (1,2). There is no investigation that can predict which recipient will develop DGF. DGF is precipitated by donor and recipients factors (prerenal, renal and postrenal) (3). One molecule that may play a role in the precipitating factors and therefore may also play a role in DGF is NO. It is essential to the kidney milieu. It has a significant effect on the haemodynamics of the kidneys. It contributes to the regulation of glomerular capillary blood pressure, glomerular blood flow and glomerular capillary ultrafiltration coefficient (4, 5). However, in ESRF, NO production is inhibited, therefore pre-transplant serum NO levels may play a role in the early function of the renal transplant. Our hypothesis is that high levels of serum NO may favor immediate graft function while low levels favors delayed graft function.
Ethical committee approval and patient consent obtained. We recruited 43 consecutive renal recipients between 2003 and 2004. . There were no exclusion criteria. Fasting blood sample was collected on admission and following renal replacement therapy. Blood sample were processed immediately. It was centrifuged at 800 for 40 minutes, serum collected and stored at -80˚ C. On the day of analysis, blood sample diluted 2-fold with Reaction Buffer and vortexed, and then 400 μmol of the prepared mixture pippetted out into a micro-centrifuge filter. We used ultrafree®-MC microcentrifuge filters (NMWL 10,000 Dalton, supplied by Sigma-Aldrich) to deproteinise the serum. This centrifuged at 8000 G for 40 minutes, yielding 100 microml of serum which was used in NO assay. For every new assay a new sample is thawed, diluted and filtered. NO is unstable molecule and within 30 second is converted to nitrate and nitrite. However, serum nitrate is the most stable end products of NO. Therefore we measured serum nitrate as an indirect measurement of NO. We measured serum nitrate using Greiss reaction (R&D System).
Delayed graft function defined as the need for dialysis in the first week after renal transplantation.
We used SPSS version 11for our analysis. Results expressed by median and Whitney-Mann used to test for statistical significance. Binary logistic regression was used for multivariate analysis.
Out of the 43 recipients, 33 had immediate graft function (IGF) and 10 had DGF. In IGF group, the median serum nitrate was 68 µmol/l. In DGF, the median serum nitrate was 47 µmol/l. There was a significant difference between both groups (P 0.013) using Mann-Whittney test. Using binary logistic regression, there was no significant difference with age, sex or type of renal replacement therapy.