Plasma Homocysteine and Glutathione Are Independently Associated With Estimated Glomerular Filtration Rates in Patients With Renal Transplants.

Background: Elevated levels of plasma homocysteine could, through homocysteine oxidation, induce the overproduction of reactive oxygen species, leading to a reduction in glutathione-related antioxidants, and may impair graft functions in patients with renal transplants. The purpose of this study was to determine whether plasma homocysteine, glutathione, or its related antioxidants were related to graft functions in patients with renal transplants.

Patients And Methods: We recruited 66 patients (mean age 48.4 years) with renal transplants (mean transplant duration 8.3 years). Patients were divided into 2 groups, based on their estimated glomerular filtration rate (eGFR): the moderate graft function group (eGFR ≥ 60 mL/min/1.73 m, n = 37) and low graft function group (eGFR < 60 mL/min/1.73 m, n = 29). We then determined their fasting levels of the following: malondialdehyde (MDA), homocysteine, cysteine, pyridoxal 5'-phosphate (PLP), glutathione (GSH), oxidized glutathione (GSSG), GSH/GSH ratio, glutathione peroxidase (GSH-Px) activity.

Results: We found in the low graft function group significantly higher levels of plasma homocysteine, cysteine, GSH, and GSH/GSSG ratios. But an intergroup difference was not found regarding levels of MDA, PLP, GSSG, and GSH-Px activity. After adjusting for potential confounders, the increased plasma homocysteine and GSH levels were independently associated with lower eGFR. No interaction existed between homocysteine and GSH levels in association with eGFR.

Conclusion: Increased plasma homocysteine and GSH levels appeared to be independent indicators of decreased graft functions in patients with renal transplants.