Albumin redox status in the context of kidney transplantation - an observational, pilot study

The albumin redox status (ARS) is altered in patients with chronic kidney disease (CKD), shifting towards a higher degree of oxidation. Oxidative Stress leads to persistent microinflammation and increased morbidity and mortality. An improvement in renal function following kidney transplantation (KTX) could lead to an improvement in ARS. Aim of this study was to evaluate the effects of KTX on ARS.

In an observational, monocentric feasibility study design, ARS was determined before and eight times up to 180 days after KTX by fractionation of albumin into reduced human mercaptalbumin (HMA), reversibly oxidized human nonmercaptalbumin 1 (HNA-1) and irreversibly oxidized human nonmercaptalbumin 2 (HNA-2) by high-performance liquid chromatography (HPLC) with fluorescence detection. In healthy individuals, HMA accounts for 70-80%, HNA-1 for 20-30% and HNA-2 for about 2-5% of total albumin.

42 patients (62% male, median age of 43.5 years) were included in the study. Before KTX, HMA was reduced (median 63.5%, interquartile range [IQR] 59.6-67.3%), while HNA-1 (28.9%, IQR 25.9-33.2%) and HNA-2 (7.1%, IQR 6.0-8.1%) were elevated compared to a healthy population. Within the first week post-KTX, HMA declined further (57.9%, IQR 53.1-63.6%) and HNA-2 peaked (9.2%, IQR 7.3-11.4%). In most patients, the ARS returned to pre-KTX level by day 60. At day 180, 31% of patients still showed HNA-1 and HNA-2 levels above the respective reference ranges reported for healthy individuals, despite substantial recovery of kidney function.

While kidney function was restored rapidly after kidney transplantation, ARS followed a slower and more variable recovery pattern, suggesting that factors beyond renal function may influence albumin redox state. Further research is needed to determine its clinical relevance and potential implications for transplant care.