GERAADA could detect significant disease- and surgery-related risk factors for death in AADA, influencing the outcome of surgically treated AADA patients. Comatose and resuscitated patients have the poorest outcome. Cannulation sites and operative techniques did not seem to affect mortality. Short operative times are associated with better outcomes.
Abstract-The aim of the present study was to investigate the effects of the novel poly(ADP-ribose) polymerase (PARP) inhibitor PJ34 (N-(6-oxo-5,6-dihydro-phenanthridin-2-yl)-N,N-dimethylacetamide) on myocardial and endothelial function after hypothermic ischemia and reperfusion in a heterotopic rat heart transplantation model. After a 1-hour ischemic preservation, reperfusion was started either after application of placebo or PJ34 (3 mg/kg). The assessment of left ventricular pressure-volume relations, total coronary blood flow, endothelial function, myocardial high energy phosphates, and histological analysis were performed at 1 and 24 hours of reperfusion. After 1 hour, myocardial contractility and relaxation, coronary blood flow, and endothelial function were significantly improved and myocardial high energy phosphate content was preserved in the PJ34-treated animals. Improved transplant function was also seen with treatment with another, structurally different PARP inhibitor, 5-aminoisoquinoline. The PARP inhibitors did not affect baseline cardiac function. Immunohistological staining confirmed that PJ34 prevented the activation of PARP in the transplanted hearts. The activation of P-selectin and ICAM-1 was significantly elevated in the vehicle-treated heart transplantation group. Thus, pharmacological PARP inhibition reduces reperfusion injury after heart transplantation due to prevention of energy depletion and downregulation of adhesion molecules and exerts a beneficial effect against reperfusion-induced graft coronary endothelial dysfunction. (Circ Res. 2002;90:100-106.)Key Words: transplantation Ⅲ reperfusion injury Ⅲ PARP inhibition Ⅲ endothelial function Ⅲ rat I schemia/reperfusion injury is a common condition during cardiac surgery. Myocardial performance within the first hours after the surgical procedure determines the patient's state not only during the postoperative period but also in the long-term outcome, especially after heart transplantation when an extended time of ischemia is followed by reperfusion. Most studies about the effects of myocardial ischemia and reperfusion focus on myocardial injury and the recovery of contractile function. It is now appreciated that the survival of the heart as a whole depends in part on the ability of the microcirculation to deliver and distribute blood flow adequately during reperfusion. Recent studies show the importance of protecting the microvasculature to attenuate reperfusion injury. 1 Therefore, novel therapeutic strategies concentrate on management modalities that prevent both myocardial and endothelial injury during reperfusion.Ischemia/reperfusion injury initiates a pathophysiological cascade including an inflammatory response with liberation of cytokines and free radicals. A recently discovered mechanism of cell injury, the poly-ADP-ribose polymerase (PARP) pathway (see Sims et al 2 and Schraufstter et al 3 ;overview in Szabó 4 ) is involved in the pathogenesis of various forms of ischemia/reperfusion injury. In 1997, Thiemermann et al 5 and Zing...
Background-Tetrahydrobiopterin (BH4), an essential cofactor for the synthesis of NO, improves endothelial dysfunction after ischemia/reperfusion. Therefore, we hypothesized that reduction of BH4 is involved in the attenuation of endothelium-dependent vasodilation in atherosclerosis, and we investigated the effect of alterations of the BH4 level on the vasodilatory potential of coronary resistance vessels from humans and pigs with atherosclerosis. Methods and Results-Coronary arterioles were obtained from patients undergoing CABG (atherosclerosis group) or valve replacement (control group) and from pigs fed either a standard diet (control group) or atherogenic diet (atherosclerosis group). After isolation, vessels were cannulated, pressurized, and placed on the stage of an inverted microscope. Dose-response curves were investigated in response to the endothelium-dependent agonists histamine, serotonin, and acetylcholine (for pigs, substance P) and to the endothelium-independent agonist sodium nitroprusside (SNP) under control conditions and before and after incubation of the vessels with sepiapterin (substrate for BH4 synthesis). In vessels from patients and from animals with atherosclerosis, compared with vessels from the control groups, there was a significant (PϽ0.05) reduction of vasodilation to all tested endothelium-dependent agonists but not to SNP. After application of sepiapterin, the responses to the endothelium-dependent agonists but not to SNP were significantly improved in vessels from the atherosclerosis groups. Sepiapterin did not influence vascular reactivity in the control groups. Conclusions-Atherosclerosis severely compromises endothelial function of coronary resistance arteries. Administration of sepiapterin leads to a significant improvement of endothelium-dependent vasodilatation to different agonists in vessels from humans and pigs with atherosclerosis. Therefore, we conclude that a reduced availability of BH4 is involved in the development of endothelial dysfunction in atherosclerosis.
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