Isoprostanes and oxidative stress in off-pump and on-pump coronary bypass surgery.

BACKGROUND: Conventional on-pump coronary artery bypass grafting (CABG) is associated with a systemic inflammatory response and by an increased production of reactive oxygen species, whereas off-pump coronary artery bypass grafting (OPCAB) is thought to be accompanied by less oxidative stress. Urinary isoprostane iPF2alpha-III is a new marker reflecting oxidative stress; it has emerged as the most reliable marker of oxidative stress status in vivo. This study was designed to ascertain whether OPCAB compared with CABG represents a surgical strategy that avoids oxidative stress. To this end urinary isoprostanes and other established oxidative stress markers were measured during the first 24 hours after CABG and OPCAB. METHODS: Fifty low-risk coronary patients were randomly assigned to CABG or OPCAB. Urinary isoprostane iPF2alpha-III levels, plasma levels of free malondialdehyde, and total antioxidant status were measured before, during, and up to 24 hours after surgery. RESULTS: In OPCAB iPF2alpha-III excretion remained unchanged throughout the study. As expected, in CABG iPF2alpha-III levels significantly increased during surgery and returned at baseline 24 hours later. Free malondialdehyde behaved similarly, with no change in OPCAB and sharp increases during CABG. Conversely, total antioxidant status showed a sharp drop during CABG, followed by a slow recovery, whereas a significantly lower drop occurred in OPCAB. CONCLUSIONS: In this randomized study in low-risk coronary patients, OPCAB revealed less perioperative oxidative stress, as reflected by lack of excretion of iPF2alpha-III in urine, by lack of increase of plasma free malondialdehyde, and by lower decreases in plasma total antioxidant status.

Lipid peroxidation and 5-lipoxygenase activity in chronic obstructive pulmonary disease.

We studied the urinary excretion of the isoprostane 8-iso-prostaglandin F(2alpha) as an index of in vivo oxidant stress, and the production of leukotriene (LT) B(4) (LTB(4)) by neutrophils in subjects with chronic obstructive pulmonary disease (COPD) and normal subjects. Overnight urinary excretion of the isoprostane was significantly higher in patients with COPD than in control subjects, and LTB(4) production by challenge of neutrophils obtained from patients with COPD was also significantly higher than that observed in control neutrophils. Treatment with a standardized polyphenol extract caused a significant decrease in isoprostane excretion, accompanied by a statistically significant increase of Pa(O(2)). Furthermore, changes in FEV(1) significantly correlated with the changes in isoprostane urinary excretion observed from enrollment to the end of treatment. The results of this study suggest that enhanced oxidative stress in subjects with COPD is paralleled by the increased ability of neutrophils to synthesize the chemotactic factor LTB(4), and may ultimately contribute to the infiltration/activation of neutrophils into the airways of subjects with COPD. Antioxidant treatment in subjects with COPD is effective in reducing oxidant stress as shown by the decrease of urinary isoprostane, a reduction that correlates with the severity of the disease, as indicated by changes in Pa(O(2)) and FEV(1).