Prevention of post-pump myocardial dysfunction by glutathione

Inflammation After Cardiopulmonary Bypass: Therapy for the Postpump Syndrome

Cardiopulmonary bypass (CPB) is used in most, but not all, complex heart operations. CPB is associated with a systemic inflammatory response in adults and children. Many materials-dependent (exposure of blood to non- physiologic surfaces and conditions) and materials-in dependent (surgical trauma, ischemia-perfusion to the organs, changes in body temperature, and release of endotoxin) factors during CPB have been implicated in the etiology of this complex response. The mechanisms involved may include complement activation, release of cytokines, leukocyte activation with expression of ad hesion molecules, and production of various vasoactive and immunoactive substances. Postpump inflamma tion may lead to postoperative complications and may result in respiratory failure, renal dysfunction, bleeding disorders, neurologic dysfunction, altered liver func tion, and ultimately multiple organ failure. Significant efforts are being made to decrease the generation and effects of postpump inflammation. Interventions to this end have included avoiding CPB when possible, im proving the biocompatibility of the involved mechani cal devices, and administering medications that main tain cellular integrity. This article provides an overview of the etiology, pathophysiology, and treatment of postpump inflammation. Perhaps with additional in sight into this syndrome, CPB can be made a safer and more efficacious modality of cardiorespiratory support. Copyright© 2001 by W.B. Saunders Company.

Schisandrin B protects against myocardial ischemia-reperfusion injury by enhancing myocardial glutathione antioxidant status

The effects of Schisandrin B (Sch B) and dimethyl-4,4'-dimethoxy-5,6,5',6'dimethylene-dioxy-biphenyl-2,2'-+ ++bicarboxylate (DDB) treatment on myocardial ischemia-reperfusion (IR) injury in isolated perfused rat hearts were examined under both in vitro and ex vivo conditions. In vitro administration of liposome-entrapped Sch B or DDB during reperfusion did not protect against myocardial IR injury, whereas ascorbic acid or Trolox supplemented perfusate produced protective effect, as evidenced by the significant decrease in the extent of lactate dehydrogenase leakage as well as an improvement in contractile force recovery. Myocardial protection afforded by N-acetyl-L-cysteine supplemented perfusate was not accompanied by the enhancement in contractile force recovery. In ex vivo experiment, pretreatment of Sch B (0.6/1.2 mmol/kg/day x 3) protected against IR-induced myocardial damage in a dose-dependent manner. The myocardial protection was associated with an enhancement in myocardial glutathione antioxidant status, as indicated by significant reductions in both the extent of IR-induced reduced glutathione depletion and inhibition of Se-glutathione peroxidase and glutathione reductase activities. In contrast, the inability of DDB pretreatment to enhance myocardial glutathione antioxidant status resulted in a failure in preventing IR injury. The ensemble of results suggests that the myocardial protection afforded by Sch B pretreatment, which was unlikely due to free radical scavenging action, may be mainly mediated by the enhancement of myocardial glutathione antioxidant status, particularly under oxidative stress conditions.