Association between blood indoxyl sulfate and carbonyl stress marker in hemodialysis patients.
BACKGROUND
Indoxyl sulfate (IS) is a protein-bound solute, which is progressively retained in blood according to the decline of renal function. However, clinical relevance of excess IS in hemodialysis (HD) patients remains unknown.


METHODS
We measured serum IS and clinical parameters including pentosidine, carboxymethyllysine (CML) and homocysteine levels in 55 HD patients (age: 67 +/- 2 years, time on HD: 67 +/- 11 months, male/female = 30/25), and examined the relationship between IS and these data.


RESULTS
Serum IS was markedly increased in HD patients (80.49 +/- 6.17 microg/ml) compared to normal range (< 1.9 microg/ml). IS was significantly and positively correlated with time on HD (p < 0.01), blood urea nitrogen (p < 0.01), beta2-microglobulin (p < 0.03), and protein catabolic rate (PCR) (p < 0.01). The patients with increased IS needed a higher erythropoietin dosage. Blood IS was positively correlated with pentosidine (r = 0.505, p < 0.01) and CML (r = 0.275, p < 0.05). In contrast, blood IS was not associated with nutritional and inflammatory parameters. A stepwise multiple regression analysis revealed that time on HD, PCR and pentosidine were significant determinants of IS.


CONCLUSIONS
Serum IS was related to time on HD and dietary protein intake. Accumulated IS may be associated with enhanced carbonyl stress in chronic HD patients.
Kato
A
A
Division of Nephrology, Endocrine and Metabolism, Shizuoka Cancer Center Hospital, Shizuoka, Japan. a.kato@scchr.jp
Odamaki
M
M
Hishida
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007200:Indican / Q000097:blood*; D008239:Lysine / Q000031:analogs & derivatives* / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D006435:Renal Dialysis; D013997:Time Factors
D015415:Biomarkers; D001798:Blood Proteins; D006710:Homocysteine; C048496:N(6)-carboxymethyllysine; D001120:Arginine; C062187:pentosidine; D008239:Lysine; D007200:Indican