Physiological response to lipid peroxidation in ischemia and reperfusion during carotid endarterectomy

The study was conducted on 30 patients undergoing carotid endarterectomy. Blood samplings were performed before, during endarterectomy in the "ischemic phase", and 30 seconds, 30 minutes and 2 hours after reperfusion.The results showed that PUFAHP increased significantly after 30 min of reperfusion in patients with controlateral stenosis > 50%, and steeply decreased after 2 hour of reperfusion. Interestingly, IP increased in a similar fashion of PUFAHP but never significantly. Both ratios CD16:2/CLA and DIN/IP also increased significantly after 30 min of reperfusion to decrease thereafter.Our data show that lipid peroxidation takes place only in patients with high controlateral stenosis and within 2 hours occurs a physiological response aimed to decrease IP and PUFAHP by increasing their catabolism in peroxisomes.Carotid endarterectomy is clinically performed to reduce the incidence of strokes in patients with carotid stenosis >70% [1]. However, surgery has some important complications, although rare, such as major or minor stroke and cerebral hyperperfusion syndrome [1]. This surgical procedure involves ischemia-reperfusion, which may induce neurooxidative stress, by free radicals formation [2-5]. Reperfused brain is particularly sensitive to oxidative stress because of a relatively modest antioxidant defenses, high mitochondrial density and neuronal membrane lipids rich in polyunsaturated fatty acid (PUFA) side chains which are particularly susceptible to free radical attack triggering lipid peroxidation [3]. The primary products of lipid peroxidation are fatty acid hydro(pero)xides among which those derived from linoleic acid are one of the most reliable marker [6]. Fatty acid hydroperoxides, are quite unstable and capable to propagate free radical reactions and thereby extending the damage.One of the most widely used indirect markers of lipid peroxidation is the detection of 8-iso-PGF2α isoprostane (IP) [7]. Its measurement has been widely employed to a great de