title: Plasma and urinary free 3-nitrotyrosine following cardiac angiography procedures with non-ionic radiocontrast media.
abstract: BACKGROUND
  Radiocontrast media (RCM) administration is a common cause of hospital-acquired acute renal failure, especially in high-risk patients, but mechanisms of nephrotoxicity have not been fully elucidated. Reactive oxidant species recently have been shown to play a role in experimental RCM nephropathy, while there is clinical evidence that acetylcysteine, an antioxidant drug, has a protective effect against RCM nephropathy in humans. However, no study has been published showing that RCM administration elicits oxidative stress in humans.
  
  
  METHODS
  In an unselected series of patients undergoing elective cardiac catheterization for coronary artery angiography and/or angioplasty, we monitored the time course of plasma and urinary levels of free 3-nitrotyrosine (3-NT), a stable marker of peroxynitrite generation resulting from the in vivo reaction of superoxide and nitric oxide. Urinary 3-NT levels were measured as the ratio of urinary 3-NT to urinary creatinine. Measurements were taken at baseline, immediately after the procedure and at 24, 48 and 72 h.
  
  
  RESULTS
  Twenty-six patients were studied (median age 67.5 years, range 42-86; baseline serum creatinine 1.0 mg/dl, 0.6-1.5; RCM dose 215 ml, 100-580). Plasma 3-NT levels slightly increased over the 72 h following the procedure (P<0.001), while urinary 3-NT levels peaked at the end of the procedure (P<0.001). Urinary 3-NT levels reached at the end of the procedure were proportional to the RCM dose administered (P = 0.017).
  
  
  CONCLUSIONS
  The present study provides indirect evidence that RCM administration in humans is associated with an increased production of 3-NT. Further studies are needed to ascertain whether oxygen- and nitrogen-derived radical species play a major role in the pathogenesis of RCM-associated nephrotoxicity in the clinical setting.
authors.affiliation: Dipartimento di Clinica Medica, Nefrologia e Scienze della Prevenzione, Università degli Studi di Parma, Via Gramsci 14, 43100 Parma, Italy. enrico.fiaccadori@unipr.it
authors.forename: Enrico
authors.initials: E
authors.lastname: Fiaccadori
authors.forename: Umberto
authors.initials: U
authors.lastname: Maggiore
authors.forename: Carlo
authors.initials: C
authors.lastname: Rotelli
authors.forename: Roberto
authors.initials: R
authors.lastname: Giacosa
authors.forename: Maria
authors.initials: M
authors.lastname: Lombardi
authors.forename: Sibilla
authors.initials: S
authors.lastname: Sagripanti
authors.forename: Silvia
authors.initials: S
authors.lastname: Buratti
authors.forename: Diego
authors.initials: D
authors.lastname: Ardissino
authors.forename: Aderville
authors.initials: A
authors.lastname: Cabassi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000097:blood* / Q000652:urine*
chemical_list: D019275:Radiopharmaceuticals; C002744:3-nitrotyrosine; D014443:Tyrosine