The uremic toxin oxythiamine causes functional thiamine deficiency in end-stage renal disease by inhibiting transketolase activity.
Kidney Int
; 90(2): 396-403, 2016 08.
Article
em En
| MEDLINE
| ID: mdl-27198804
ABSTRACT
Decreased transketolase activity is an unexplained characteristic of patients with end-stage renal disease and is linked to impaired metabolic and immune function. Here we describe the discovery of a link to impaired functional activity of thiamine pyrophosphate cofactor through the presence, accumulation, and pyrophosphorylation of the thiamine antimetabolite oxythiamine in renal failure. Plasma oxythiamine was significantly increased by 4-fold in patients receiving continuous ambulatory peritoneal dialysis and 15-fold in patients receiving hemodialysis immediately before the dialysis session (healthy individuals, 0.18 [0.11-0.22] nM); continuous ambulatory peritoneal dialysis patients, 0.64 [0.48-0.94] nM; and hemodialysis patients (2.73 [1.52-5.76] nM). Oxythiamine was converted to the transketolase inhibitor oxythiamine pyrophosphate. The red blood cell oxythiamine pyrophosphate concentration was significantly increased by 4-fold in hemodialysis (healthy individuals, 15.9 nM and hemodialysis patients, 66.1 nM). This accounted for the significant concomitant 41% loss of transketolase activity (mU/mg hemoglobin) from 0.410 in healthy individuals to 0.240 in hemodialysis patients. This may be corrected by displacement with excess thiamine pyrophosphate and explain lifting of decreased transketolase activity by high-dose thiamine supplementation in previous studies. Oxythiamine is likely of dietary origin through cooking of acidic thiamine-containing foods. Experimentally, trace levels of oxythiamine were not formed from thiamine degradation under physiologic conditions but rather under acidic conditions at 100(°)C. Thus, monitoring of the plasma oxythiamine concentration in renal failure and implementation of high-dose thiamine supplements to counter it may help improve the clinical outcome of patients with renal failure.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Oxitiamina
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Deficiência de Tiamina
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Tiamina Pirofosfato
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Transcetolase
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Falência Renal Crônica
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Antimetabólitos
Tipo de estudo:
Etiology_studies
Limite:
Adult
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article