摘要:

Mitochondria may be a source of molecules that activate complement during ischemic injury to myocardium, providing therewith a stimulus for infiltration of polymorphonuclear leukocytes. To identify specific molecules that activate the classical complement pathway, detergent lysates of canine cardiac mitochondria were fractionated by polyacrylamide gel electrophoresis and transferred electrophoretically to nitrocellulose paper (NCP). The NCP replicas of the gels were incubated with isolated Clq and fresh sera as a source of complement, washed briefly, and overlaid with sensitized sheep erythrocytes (RBC) in agarose. A cluster of four to six molecules between 45 and 53 kDa as well as four others, 34, 30, 26, and 23 kDa, consumed complement thereby preventing complement-mediated lysis of sensitized sheep RBC in the agarose overlay. Additional molecules reactive with Cl were identified by their ability to bind isolated human Clq and to serve as assembly sites for later acting complement components. Sites of localization of complement were demonstrated by incubating NCP replicas of fractionated mitochondria with antisera specific for Clq, C3, C5, and C9, followed by peroxidase-conjugated anti- immunoglobulin and substrate. A total of 12 Clq binding molecules ranging in size from 67 kDa to 23 kDa, which can fix later acting complement components, were identified. At least two of these reacted with antisera prepared against canine cardiac lymph collected in the first 3–4 hours after a 45-minute coronary artery occlusion. These studies present direct evidence that specific molecules, released from subcellular fractions of myocardial cells rich in mitochondria, can activate the complement cascade.

ISSN:0009-7330    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Previous studies have revealed that the regional accumulation of ischemic metabolites including hydrogen ion (H+) and PcO2diminish after repeated occlusions. We postulated that tins diminution reflects a blunted metabolic response that is related to the severity of ischemic injury and, hence, may be most pronounced in subendocardial (ENDO) regions. To investigate tins hypothesis, the left anterior descending coronary artery was serially occluded three times in 51 dogs for a period of either 3 minutes (n=15), 5 minutes (n=18), or 15 minutes (n=18). Each occlusion was separated by 45 minutes of reperfusion. Myocardial [H+] was measured in the endomyocardium and in the epimyocardium of the ischemic anterior wall by use of miniature pH glass electrodes. Accumulation of H+during occlusion (A[H+]) in the ENDO region was significantly less during the second occlusion when compared with the first occlusion (3-minute occlusions: 28.2±3.7 nM/l vs. 39.4±5.4 nM/l, p<0.002; 5-minute occlusions: 49.8±5.0 nM/l vs. 72.1±6.5 nM/l, p<0.0002; 15-minute occlusions: 132.3±14.6 nM/1 vs. 225.6±27.7 nM/1, p<0.0003). A similar trend was noted for A[H+] in the subepicardial (EPI) regions. During occlusion, the rise in [H+] occurred sooner, and A[H+] was consistently greater in the ENDO when compared with the EPI regions (p<0.05). Regional myocardial blood flow did not change during the three occlusions, indicating that the diminution in H+accumulation stemmed from a decrease in H+production and not from an increase in collateral flow. The decrement in H+accumulation between the first and second occlusions (±[H+]|-±A[H+]2)1 was greater in the ENDO than in the EPI regions (p<0.05); 2) correlated with the duration of occlusion (ENDO: r=0.66, p<0.001; EPI: r=0.82, p<0.0001); and 3) was related to the impairment of anterior wall systolic shortening after the first reperfusion period. These findings suggest that the diminution in H+production that follows serial coronary occlusions reflects a blunted metabolic response that is related to both the duration of ischemia and the degree of systolic dysfunction. Moreover±, though attenuation of ischemic metabolite production occurs transmurally, it is most pronounced in the deep ENDO regions.

ISSN:0009-7330    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:0009-7330    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:0009-7330    

出版商:OVID    

年代:1989

数据来源: OVID