Apoptosis of tubular epithelial cells in preimplantation biopsies of kidney grafts with immediate, slow and delayed function

Background: Apoptosis is a form of cell death observed in kidney grafts as a  result of ischemia/reperfusion injury. Patients who develop slow (SGF) or delayed (DGF) graft function present worse kidney graft survival compared to those with immediate graft function (IGF). The aim of our prospective study was to analyse the occurrence of apoptotic cells in the kidney tubules after cold storage in respect to post-transplant graft function.
Material/Methods: The degree of renal tubular damage was estimated as  percentage (TUNEL method) of apoptotic cells in 72 pre-implantation kidney biopsies in proximal and distal tubules. Biopsies which not fulfilled Banff 97 classification (N=5) and of patients with early acute rejection (N=8) or early graft loss (N=3) were excluded from the analysis. IGF (N=17) was defined as serum creatinine level (SCr) <264 μmol/l at 3rd postoperative day (POD); SGF (N=20) - as SCr >264μmol/l at 3rd POD and the need of maximum one dialysis; DGF (N=19) - when patient required more than one dialysis. Data are presented as means and 95% CI.
Results: The percentage of apoptotic cells was markedly higher in distal than in proximal tubules in all three groups. The highest percentage of apoptotic cells in distal tubules was found in IGF [3.02(1.03-5.00)] than in SGF [1.66(0.92-2.39)] and in DGF [1.76(0.84-2.68)], however these differences did not reach statistical significance.
Conclusion: The enhancement of tubular epithelial cells apoptosis in kidney grafts after cold storage does not determine their early function.

Keywords: Ischemia reperfusion injury, Kidney Transplantation