Homocysteinemia correlates with plasma thiol redox status in patients with end-stage renal disease.
OBJECTIVE
In end-stage renal disease (ESRD), hyperhomocysteinemia is a common finding associated with increased cardiovascular risk. However, the pathogenic role of homocysteine is still unclear. In vitro studies show that thiol redox status affects endothelial cell functions. We therefore investigated the possible association between homocysteinemia and plasma thiol redox status in ESRD patients.


METHODS
Total plasma homocysteine (Hcy), cysteine (Cys) and free thiols (SH) were measured both before and after a dialytic session in 54 ESRD patients receiving (n = 15) or not receiving (n = 39) folate supplementation, and 17 control subjects.


RESULTS
High predialysis levels of both Hcy and Cys were found to be negatively correlated with low SH levels both in supplemented (r = -0.680, p < 0.01 and r = -0.624, p < 0.02, respectively) and unsupplemented (r = -0.698, p < 0.001 and r = -0.445, p < 0.01, respectively) patients. Following dialysis, SH values returned to normal and the above correlations were no longer appreciable.


CONCLUSIONS
A strong, folate therapy-insensitive association between homocysteinemia and plasma free thiol levels was found in ESRD patients. These results support a role for oxidative stress in ESRD-related hyperhomocysteinemia and suggest the plasma thiol redox status alteration as a possible pathogenic mechanism underlying the cardiovascular toxicity of hyperhomocysteinemia in these patients.
Palleschi
Simonetta
S
Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy. simonetta.palleschi@iss.it
De Angelis
Sandro
S
Rossi
Barbara
B
Diana
Loretta
L
Papa
Vincenza
V
Severini
Giancarlo
G
Splendiani
Giorgio
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003545:Cysteine / Q000097:blood* / Q000187:drug effects; D003956:Dialysis / Q000379:methods; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000494:pharmacology; D006710:Homocysteine / Q000097:blood* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood* / Q000150:complications; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D018709:Statistics, Nonparametric; D013438:Sulfhydryl Compounds / Q000097:blood* / Q000378:metabolism; D014803:Vitamin B Complex / Q000008:administration & dosage / Q000494:pharmacology
D013438:Sulfhydryl Compounds; D006710:Homocysteine; D014803:Vitamin B Complex; D005492:Folic Acid; D003545:Cysteine