Clinical and pathological features of donor/recipient body weight mismatch after kidney transplantation

BackgroundPrevious studies have shown that a donor/recipient body weight mismatch affects long-term graft survival and graft function after kidney transplantation. However, the mechanisms are not fully understood. AimTo address the mechanisms, we compared the pathological and physiological features between patients with a donor/recipient body weight mismatch and those without a mismatch 1yr after kidney transplantation. Furthermore, we investigated the correlation with the donor/recipient body weight ratio. MethodsWe examined allograft biopsy specimens from 10 recipients with stable kidney function, with body weight mismatch (donor/recipient body weight ratio [D/R BWR]<0.9), and compared them with samples from 13 patients without mismatch. We measured glomerular volume (GV) using the Weibel-Gomez method and glomerular density (GD) defined by nonsclerotic glomerular number/renal cortical area as pathological findings. The physiological parameters included estimated glomerular filtration rate and proteinuria (mg/day). These data were evaluated to identify a correlation with D/R BWR. ResultsThe pathological features showed that GV and GD were identical in the two groups. However, when glomerular enlargement was defined by GV (GV at the 1-yr biopsy minus GV at baseline biopsy), GV was higher in mismatch cases compared with that in cases without a mismatch (10.64.6 vs. 5.5 +/- 7.1x10(5)m(3); P=0.049). Furthermore, D/R BWR was significantly correlated with GV (P=0.03, r=-0.436). eGFR values were physiologically identical between the two groups, but the mismatch cases had significantly higher proteinuria levels than that of the cases without a mismatch at 1yr after kidney transplantation. ConclusionA donor/recipient body weight mismatch could affect glomerular enlargement and increased proteinuria 1yr after kidney transplantation. How these two features affect long-term graft survival and function must be addressed in the future.