The effects of cytochrome C on the extent of myocardial infarction and regional function of the ischemic myocardium

Expression and characterization of recombinant human cytochrome c in E. coli

Cytochrome c is a heme protein involved in electron transfer, cell apoptosis, and diseases associated with oxidative stress. Here we expressed human cytochrome c in E. coli and purified it to homogeneity with a yield of 10-15 mg/L. The redox potential of recombinant human cytochrome c was 0.246 V which was measured by cyclic voltammetry. This is similar to that of horse cytochrome c with a value of 0.249 V. The sequential assignment and structural analysis of recombinant human ferrocytochrome c were obtained using multidimensional NMR spectroscopy. On the basis of our NMR studies, the recombinant human cytochrome c produced in E. coli exhibits the same tertiary fold as horse cytochrome c. These results provide evidence that human cytochrome c expressed in E. coli possesses a similar function and structure to that of the horse protein. It is known that cytochrome c plays a role in many human diseases. This study serves as the basis for gaining insight into human diseases by exploring structure and function relationships of cytochrome c to its interacting proteins.

Does antiplatelet therapy enhance myocardial salvage after coronary reperfusion?

The aim of this study was to test the hypothesis that either the cyclooxygenase inhibitor aspirin or the thromboxane A2 receptor antagonist sulotroban exerts a direct myocardial effect that enhances myocardial salvage afforded by reperfusion. Accordingly, 21 anesthetized dogs underwent suture occlusion of the left anterior descending coronary artery. At 2.5 h after occlusion, all dogs received intravenous streptokinase (20,000 U/kg body weight over 30 min) and were randomized to the following groups: group I (n = 7) received no additional treatment, group II (n = 7) received aspirin (5 mg/kg intravenously) and group III (n = 7) received sulotroban (10 mg/kg followed by 10 mg/kg per h intravenously). At 3 h after occlusion, the dogs underwent coronary reperfusion for the next 3 h. Myocardial infarct size as a percent of the hypoperfused zone was similar among dogs in group I (42 +/- 8%), group II (41 +/- 10%) and group III (45 +/- 11%). The incidence and the extent of myocardial hemorrhage were similar in all three study groups. Infarct size as a percent of the hypoperfused zone was significantly smaller in dogs without hemorrhage irrespective of treatment (35 +/- 9% versus 63 +/- 5%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial protection with autoperfusion during prolonged coronary artery occlusion

Passive transcatheter coronary arterial perfusion, i.e., autoperfusion, has been introduced for clinical use to ameliorate short episodes of myocardial ischemia during percutaneous transluminal coronary angioplasty. The primary goal of this study was to evaluate the cardioprotective effect of autoperfusion after prolonged coronary artery occlusion. Accordingly, in 24 anesthetized dogs, either the left anterior descending or left circumflex coronary artery was occluded for 6 hours. The dogs were randomized to a control group subjected to coronary artery occlusion alone (n = 13) or to a group treated with transcatheter autoperfusion (n = 11). The hypoperfused zone, i.e., risk area and infarct size, were measured by autoradiography and triphenyltetrazolium chloride staining, respectively. The hypoperfused zone was 30 +/- 2% and 29 +/- 2% in the control and treated (NS) groups, respectively. When infarct size was expressed as a percent of the hypoperfused zone, it was 84 +/- 5% in the control group and 25 +/- 9% in the group treated with transcatheter autoperfusion (p less than 0.001), showing a reduction of 70%. In addition, an in vitro study showed pressure-dependent flow during autoperfusion as reflected by close linear relationship between perfusion pressure and flow (Flow = 0.54 X Pressure + 16.16, r = 0.99, n = 16). These data suggest that although passive coronary arterial perfusion for 6 hours after coronary occlusion does not prevent myocardial necrosis, it markedly reduces myocardial infarction in the canine model.