Alteration in plasma levels of nonprotein sulfhydryl compounds and S-nitrosothiols in chronic renal failure patients.
BACKGROUND
Uremia is accompanied by the elevated nitric oxide (NO) synthesis, and it has not yet been established how this influences the levels of nonprotein sulfhydryl compounds (NPSH) and formation of S-nitrosothiols (SNT).


METHODS
Our study was designed to determine plasma levels of SNT and NPSH in chronic renal failure (CRF) patients, who were hemodialysed (HD) or were not on hemodialysis treatment (ND), and in the control group.


RESULTS
In ND patients, the plasma levels of SNT were significantly increased (11.25+/-2.08 nmol/ml, p<0.01), while NPSH levels were simultaneously decreased (66.67+/-15.0 nmol/ml, p<0.05) in comparison with the control subjects (SNT: 8.75+/-2.08 nmol/ml, NPSH: 86.66 nmol/ml). In HD patients, plasma concentration of SNT before hemodialysis was significantly lower than in the control group (0.150+/-0.042 nmol/mg protein vs. control: 0.175+/-0.075 nmol/mg protein), and no significant change was observed after dialysis (0.142+/-0.058 nmol/mg protein, p<0.05). The level of NPSH in HD patients before dialysis was significantly decreased in comparison with the control subjects, both, when the results were calculated per 1 ml of plasma (45.96+/-17.87 nmol/ml) and per 1 mg of protein (0.70+/-0.25 nmol/mg protein). In the postdialysis samples, NPSH rose (79.15+/-22.9 nmol/ml, p<0.001 which corresponds to 1.30+/-0.55 nmol/mg protein, p<0.001) as compared to the level before dialysis.


CONCLUSIONS
Firstly, plasma SNT level was found to be increased in CRF patients who were not treated with hemodialysis, while in HD patients, it dropped below the control values. It indicates that hemodialysis disturbs an equilibrium of reactions involved in S-nitrosothiols formation most probably by removing low molecular weight S-nitrosylating compounds. Secondly, the increased level of NPSH after each hemodialysis session indicates reestablished antioxidant capacity of plasma and suggests the existence of dialysable compounds, which via unknown mechanism become responsible for the decreased level of thiols.
Włodek
Przemysław J
PJ
Department of Nephrology, Rydygier's Hospital, Os Złotej Jesieni 1, 31-826, Cracow, Poland.
Kucharczyk
Justyna
J
Sokołowska
Maria M
MM
Miłkowski
Andrzej
A
Markiewicz
Adam
A
Smoleński
Olgierd B
OB
Włodek
Lidia B
LB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood; D006435:Renal Dialysis / Q000009:adverse effects; D026403:S-Nitrosothiols / Q000097:blood*; D013438:Sulfhydryl Compounds / Q000097:blood*; D014511:Uremia / Q000097:blood
D026403:S-Nitrosothiols; D013438:Sulfhydryl Compounds; D009569:Nitric Oxide