Carbon monoxide protects against ischemia-reperfusion injury in vitro via antioxidant properties.

Carbon monoxide (CO) is believed to mediate many of the cytoprotective effects attributed to the activation of heme oxygenase (HO-1), the enzyme responsible for CO production. Recently, the study of CO-releasing molecules (CO-RMs) has provided a new approach for the delivery of CO. In the present study, we examined whether the cardioprotective properties of CO-RM2 in isolated rat hearts subjected to an ischemia-reperfusion (I/R) sequence were associated with the presence of CO. In addition, the antioxidant properties of CO-RM2 were evaluated. In hearts pretreated with CO-RM2, the improvement in contractile function at the end of the reperfusion period after 20 min of global total ischemia was significantly greater than in controls. These beneficial effects were accompanied by a reduction in 1) LDH activity release 2) infarct size 3) ventricular superoxide production. The improvement in myocardial function and the reduction in oxidative stress were not observed when hearts were pretreated with inactivated CO-RM2 (iCO-RM2). Additionally, CO-RM2, but not iCO-RM2, was found to exert antioxidant properties. These results suggest that the production of CO is a necessary factor in the cardioprotective and antioxidant actions of CO-releasing compound. These results may open up new ground for a novel class of cardioprotective compounds.

Clinical experience with a novel thermosensitive temporary coronary artery occluder (LeGoo).

BACKGROUND: A bloodless field is important for visualizing relevant anatomical structures and facilitating construction of high-quality coronary anastomoses during off-pump coronary artery bypass graft surgery (OPCABG). Currently employed devices can damage target arteries as well as myocardium and are not uniformly effective, especially with diseased arteries. METHODS: LeGoo (Pluromed, Woburn, MA) is a thermosensitive polymer that is a viscous liquid at room temperatures and changes into a firm occlusive plug instantaneously when exposed to body temperatures. The polymer is nontoxic and neither metabolized nor absorbed. It dissolves spontaneously or can be dissolved at will by cooling. LeGoo was instilled through the arteriotomy of 99 coronaries in 50 patients during construction of OPCABG anastomoses. RESULTS: LeGoo formed an occlusive endoluminal plug instantaneously and blocked blood flow into the surgical field. In 89 vessels with available information, the quality of bloodless field was satisfactory, without need for substantial use of blood removal systems or application of another device in 81 vessels (91%). Resort to other means was prompted by serious arrhythmia (1 case) epicardial bleeding (1 vessel), bleeding from collateral branches (3 vessels), and shortcomings in design of the injecting catheter (3 vessels) that has been corrected. Intraoperative and perioperative profiles of these patients were similar to those reported from other OPCABG series. Abnormal bleeding, coagulopathy, metabolic derangements, and evidence of LeGoo embolization were not observed. CONCLUSIONS: In this first large-scale human experience, LeGoo had been an atraumatic, safe, and effective temporary coronary artery occluder. It produced a bloodless field during OPCABG in 91% of target vessels. Improvements on these results with further experience is anticipated.