Anesthetic propofol enhances plasma gamma-tocopherol levels in patients undergoing cardiac surgery

Propofol (2,6-diisopropylphenol) is an anesthetic drug with antioxidant and antiinflammatory properties, documented both in vitro and in experimental models of ischemia-reperfusion injury and septic shock. These properties have been related to the similarity of its chemical structure to that of endogenous tocopherols, which are phenol-containing radical scavengers. This study evaluated the effects of propofol on alpha- and gamma-tocopherol (alpha- and gamma-T) levels and on selected markers of oxidant-antioxidant and inflammatory status in patients undergoing cardiac surgery.

Patients were randomly assigned for anesthesia with either propofol (propofol group, n = 22) or sevoflurane (control group, n = 21). Plasma levels of alpha- and gamma-T, individual antioxidant capacity, malondialdehyde, and interleukin 10 were measured before, during, and after anesthesia. In addition, levels of the proinflammatory prostaglandin E2 as a marker of cyclooxygenase-2 activity and those of interleukin 10 were measured in whole blood cultured with bacterial lipopolysaccharide.

Gamma-T levels increased significantly during surgery in propofol group (P < 0.0001 vs. control group). By contrast, alpha-T similarly decreased in both groups. Malondialdehyde and interleukin 10 increased markedly and individual antioxidant capacity decreased, without differences between groups. Prostaglandin E2 levels measured 24 h after anesthesia induction were significantly lower in the propofol than in the control group. In vitro studies highlighted the different capacity of gamma- and alpha-T to impair prostaglandin E2 synthesis by human monocytes challenged with bacterial lipopolysaccharide.

The antiinflammatory properties of propofol that may be linked to its effect on gamma-T levels could be relevant in controlling the inflammatory response that accompanies tissue injury during reperfusion.