Original ArticlesClinical Evidence of Peroxynitrite Formation in Chronic Renal Failure Patients with Septic Shock
Introduction
There is an increasing body of evidence showing that in septic shock nitric oxide synthase is rapidly induced, leading to the excessive production of nitric oxide (NO), a potent vasodilator. Thus, NO is proposed as a major molecule responsible for circulatory shock.1, 2, 3On the other hand, abundant evidence supports the notion that in septic condition superoxide (O2−) production is augmented.[4]Under circumstances where both NO and O2− are produced, they react with each other at a diffusion limited rate to form peroxynitrite (ONOO−).[5]ONOO− is a potent oxidant which by nitrating cellular constituents[6]may play an important role in tissue damage of rheumatic arthritis,[7]acute lung injury,[8]and myocyte injury.[9]Although it is plausible that enhanced production of both NO and O2− in sepsis may lead to the formation of ONOO−, investigations that relate ONOO− with septic shock have not been undertaken. Here we present evidence of ONOO− production in septic shock by measuring plasma nitrotyrosine, which is a nitrated product of tyrosine in blood or tissue and whose presence infers ONOO− attack on tyrosine residues of protein and nonprotein origins. The reason to select nitrotyrosine as an index for production of ONOO− is based on the fact that direct measurement of ONOO− in vivo is difficult because of its very short half-life.[5]The investigation was focused on patients with chronic renal failure who were complicated by septic shock, because nitrotyrosine was shown to be rapidly excreted in the urine.[10]Patients with chronic renal failure without septic shock and healthy volunteers served as comparison. Plasma nitrite+nitrate (NOx), an end product of NO synthesis, was also measured to provide actual evidence for the increased production of NO.
Section snippets
Patients and Methods
Ten healthy volunteers were members of the hospital staff (6 men and 4 women, mean age 36.7 ± 10.0 years). Ten patients with chronic renal failure without sepsis (8 men and 2 women, mean age 52.9 ± 17.2 years) were consecutively selected from routine hemodialysis sessions. They gave their informed consent. Three patients with chronic renal failure with septic shock were a 72-year-old woman with sepsis induced by diverticulitis, a 68-year-old woman who developed sepsis during a course of
Results
Fig. 1A demonstrates the chromatogram of plasma from the patient with chronic renal failure and septic shock. Well-defined peaks at the retention time of tyrosine and nitrotyrosine were observed. The peak assigned to nitrotyrosine was eliminated with Na2S2O4 treatment, which confirmed that the peak is attributable to nitrotyrosine (Fig. 1B). In plasma of healthy volunteers, nitrotyrosine was not detectable and NOx was 28.7 ± 11.6 μM (Fig. 2). Renal failure patients without septic shock
Discussion
Our results show that plasma nitrotyrosine and NOx were increased in renal failure patients and the increases were more marked in patients complicated by septic shock. The rise in concentrations of both nitrotyrosine and NOx implies either an increased production of these molecules and/or their increased accumulation due to impaired excretion because both molecules are mainly eliminated through the kidney.[10]Although the dietary nitrate is known to influence the plasma NOx level, it is less
Acknowledgements
We thank Dr. Dennis J. Stuehr, Cleveland Clinic Foundation Research Institute for helpful discussion and peer review. This work was supported in part by Grand-in-Aid for International Scientific Research Program (No. 05045052) and Developmental Scientific Research (No. 07557006) from Ministry of Education, Science and Culture of Japan.
References (14)
- et al.
Evidence for nitric oxide-mediated oxidative damage in chronic inflammation—Nitrotyrosine in serum and synovial fluid from rheumatoid patients
FEBS. Lett.
(1994) - et al.
Peroxynitrite-induced cardiac myocyte injury
Free. Radic. Biol. Med.
(1996) - et al.
Nitrotyrosine as a new marker for endogenous nitrosation and nitration of proteins
Fundam. Chem. Toxicol.
(1990) - et al.
Conversion of 3-nitrotyrosine to 3-aminotyrosine in peptides and proteins
Biochem. Biophys. Res. Commun.
(1967) - et al.
Enhanced nitric oxide synthesis in uremia: Implications for platelet dysfunction and dialysis hypotension
Kidney Int.
(1993) - et al.
Quantitation of protein tyrosine, 3-nitrotyrosine, and 3-aminotyrosine utilizing HPLC and intrinsic ultraviolet absorbance
Methods
(1995) - et al.
Plasma nitrate concentrations in neutropenic and non-neutropenic patients with suspected septicaemia
Br. J. Haematol.
(1995)