Functional relationship of α-glutathione S-transferase and glutathione S-transferase activity in machine-preserved non-heart-beating donor kidneys

Abstract.

α-Glutathione S-transferase (α-GST) is a biochemical parameter used to estimate the amount of proximal tubule damage to a kidney. In normal clinical practice, the concentration of α-GST in urine is determined by a rather time-consuming immunochemical test, the enzyme-linked immunosorbent assay (ELISA). Kidneys from non-heart-beating (NHB) donors are perfused prior to transplantation. The determination of α-GST concentration in the perfusate to monitor damage is also done by means of an ELISA test. However, because this is a time-consuming method, it would be helpful to find a parameter proportional to GST concentrations that would be available within minutes. We therefore compared the method of determining α-GST concentration via ELISA with that of determining the enzymatic activity of GST, which is much faster (results available within 10 min). The comparison was made using 150 preserved kidneys that had been perfused for 6 h. The correlation was found to be very good, as indicated by the linear regression data: r=0.954, P<0.001. π-Glutathione S-transferase (π-GST) was also determined by means of an ELISA test, and the concentration of π-GST was compared with the enzymatic activity of the "total" GST. The precision of the enzymatic method, given by intra- and interassay variation, was 1.5% and 10.5%, respectively.