Plasma and neutrophil protein tyrosine nitration in septic patients

CARRERAS MC; RIOBó N; BAREDES N; PARGAMENT G; CONVERSO D; DEL BOSCO G; PODEROSO JJ

Florianópolis, Brasil

Congreso; First Meeting of the South American Group for Free Radical Research; 1999

South American Group for Free Radical Research

Recently, nitric oxide (NO) and peroxynitrite (ONOO-) have been implicated as mediators of inflammation and sepsis. Both increased concentrations of NO-derived metabolites (nitrites and nitrates, collectively named NOx) and reduced respiratory burst capacity of circulating neutrophils have been observed in patiens with multi organ dysfuntion syndrome (MODS). Our goal was to study a possible relationship between plasmatic and neutrophil protein nitration levels and severity of disease. We compared three groups of patients: healthy control (C), patients with systemic inflammatory response syndrome (SIRS) and patients with MODS, n=9 for each group. Patients were scored by clinical data and evidence of bacterial infection or sepsis focus. Those patients treated with steroid drugs or sodium nitropruside were excluded. Plasma NOx were determined by reduction of nitrites, followed by Griess reaction. Nitration in plasma and neutrophils proteins was analized by Western and Slot Blot with anti-nitrotyrosine antibodies. The content of NOx was significantly increased in the MODS group (23±5 ìM*) when compared with the control values (8±1 ìM), but not in SIRS patients (5±1ìM) (*p<0.05). Plasmatic nitration levels were higher in MODS patients that SIRS and controls, showing mainly two bands, one with a molecular weight similar to albumin and the other of 106 KDa. Similarly, tyrosine nitration of circulating neutrophils was increased in MODS patients. We conclude that an increase in protein tyrosine nitration, both in plasma proteins and circulating leukocytes, could be related to organ dysfunction during septic syndrome development.