Accumulation of cyanide and thiocyanate in haemodialysis patients

• Published in: Nephrology, dialysis, transplantation Vol. 19; no. 6; pp. 1474 - 1479
• Main Authors: Hasuike, Yukiko, Nakanishi, Takeshi, Moriguchi, Rintarou, Otaki, Yoshinaga, Nanami, Masayoshi, Hama, Yasue, Naka, Miki, Miyagawa, Koji, Izumi, Masaaki, Takamitsu, Yoshihiro
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.06.2004
• Subjects: Adult; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Chromatography, High Pressure Liquid; chronic renal failure; cyanide; Cyanides - metabolism; cysteine; Cysteine - blood; Emergency and intensive care: renal failure. Dialysis management; Erythrocytes - metabolism; Female; Glomerulonephritis; haemodialysis; Humans; Intensive care medicine; Kidney Failure, Chronic - metabolism; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Nephropathies. Renovascular diseases. Renal failure; Regression Analysis; Renal Dialysis; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the urinary system; thiocyanate; Thiocyanates - metabolism; Thiosulfates - metabolism; Kidney disease; Human; Thiol; Cysteine; Urinary system disease; Hemodialysis; chronic renal failure; haemodialysis; Cyanides; cyanide; thiocyanate; Accumulation; Sulfur containing aminoacid; Extrarenal dialysis; Renal failure
• ISSN: 0931-0509; 1460-2385
• DOI: 10.1093/ndt/gfh076

Background. Cyanide is a toxic agent, and its detoxification product, thiocyanate, may be a major pathogenetic substance in uraemia. Recent studies examining the myeloperoxidase(MPO)/thiocyanate system have suggested a link between thiocyanate and atherosclerosis. However, inaccuracies in conventional assays for cyanide and thiocyanate have limited the understanding of their metabolism in haemodialysis (HD) patients. Methods. We used high-performance liquid chromatography to measure cyanide in erythrocytes and thiocyanate in plasma in 43 HD patients and in a group of 46 healthy controls that included 15 current smokers. To clarify the metabolic conversion of cyanide to thiocyanate in uraemic patients, we also measured cysteine and sulfate. We then used stepwise regression analysis to analyse factors that determine erythrocyte cyanide and plasma thiocyanate. Results. Mean cyanide and thiocyanate were significantly greater in HD patients than in non-smoking controls. However, cyanide was far below lethal concentrations in dialysis patients. Thiocyanate was six to seven times greater in HD patients than in non-smoking controls, and decreases in thiocyanate following dialysis were only 19.3±3.5%. Multiple regression analysis showed a positive correlation between cyanide and thiocyanate in controls, but a negative correlation in HD patients. In patients, an inverse relationship between thiocyanate and BUN was also observed. Conclusions. The elevation of thiocyanate in patients undergoing dialysis probably is secondary to both limited efficiency of HD and deranged metabolism of cyanide and thiocyanate. Because thiocyanate is a preferred substrate for MPO, it may play a role in uraemic complications including cardiovascular events.