Reactive oxygen species and adhesion formation: clinical implications in adhesion prevention

Postoperative adhesion formation is a major clinical problem.It has been demonstrated that the pneumoperitoneum used duringlaparoscopy is a cofactor in adhesion formation. Reactive oxygenspecies (ROS) are produced in a hyperoxic environment and duringthe ischaemia/reperfusion process. ROS activity is deleteriousfor cells, which protect themselves by an antioxidant systemknown as ROS scavengers. ROS activity can increase by up-regulationof ROS themselves or by down-regulation of ROS scavengers. Recentdata also point to a role for ROS in adhesion formation sincethe administration of ROS scavengers decreases adhesion formationin several animal models. ROS activity increases during bothlaparotomy and laparoscopy. During laparoscopy, the pneumoperitoneumdetermines ischaemia at the time of insuflation and reperfusionat the time of deflation. During laparotomy, the environmenthas a 150 mmHg partial pressure of oxygen (pO₂), which is muchhigher than the intracellular pO₂ (5–40 mmHg). This canexplain the increase in ROS activity. The aim of this debateis to open a discussion about the importance of ROS activity,besides the known players and mechanisms involved, in adhesionformation and in adhesion prevention.