Use of two biomarkers of renal ischemia to assess machine-perfused non-heart-beating donor kidneys.

Abstract

Renal transplantation is a recognized treatment for end-stage renal failure, offering a better quality of life, independence from dialysis, better survival rates, and decreased cardiovascular complications compared with renal replacement therapy (1). Recently, continued increases in the prevalence of end-stage renal failure and the length of transplantation waiting lists have not been matched by an increased supply of donors from the traditional brainstem dead donors and living donors. Non-heart-beating donor (NHBD) kidneys are regaining importance to substantially increase the kidney donor pool, with estimates indicating a potential increase of 20–40% (2)(3). The use of NHBD kidneys is associated with the development of two adverse conditions, primary nonfunction (PNF) and delayed graft function (DGF), which are caused by the ischemic injury that occurs after cardio-respiratory arrest. Therefore, in centers with NHBD programs, it has become necessary to screen-out damaged kidneys that will never work. Machine preservation using continuous hypothermic pulsatile perfusion has been adopted in NHBD kidney screening initiatives, and perfusion characteristics (flow, pressure, resistance, temperature, weight gain) with enzyme analysis of kidney effluents are used to assess viability. Since its isolation and identification as ligandin, glutathione S -transferase (GST) has evolved as a suitable biomarker in the pretransplantation assessment of machine-perfused NHBD kidneys. Different isoforms have been identified from the distal and proximal renal tubules, and the commonest isoform, α-GST, has previously been used as a biomarker of renal ischemia as assessed by ELISA (4). However, we have previously demonstrated that a spectrophotometric assay for total GST activity (tGST) could reliably be substituted for α-GST (5). Original work by the Maastricht NHBD group has established threshold limits for tGST activity in kidney perfusates for the selection of “viable” kidneys for transplantation (6). This criterion has been introduced in Newcastle, England, where 69 NHBD renal transplants have …