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Coronary trapping of a complement activation product (C3a des-Arg) during myocardial reperfusion in open-heart
Insights
Complement activation product C3a des-Arg accumulates in the heart during early reperfusion after myocardial infarction. This early trapping of C3a des-Arg may contribute to ischemia-reperfusion injury.
Area of Science:
- Cardiovascular Medicine
- Immunology
- Biochemistry
Background:
- Complement factors accumulate in the myocardium post-infarction.
- The role of complement activation products during myocardial ischemia-reperfusion is not fully understood.
Purpose of the Study:
- To investigate the trapping of C3a des-Arg in the coronary circulation during reperfusion of ischemic myocardium.
- To determine if C3a des-Arg trapping correlates with arterial concentrations and myocardial injury.
Main Methods:
- Blood samples were collected from 11 patients undergoing coronary artery bypass grafting before, during, and after cardiopulmonary bypass.
- Arterial and coronary sinus blood were sampled 5 and 30 minutes after aortic cross-clamp release.
- Concentrations of C3a des-Arg were measured using immunoassay.
Main Results:
- C3a des-Arg levels significantly increased during cardiopulmonary bypass.
- A significant difference in C3a des-Arg levels between arterial and coronary sinus blood was observed at 5 minutes post-reperfusion.
- The amount of trapped C3a des-Arg at 5 minutes positively correlated with arterial C3a des-Arg concentration.
Conclusions:
- Complement activation product C3a des-Arg is trapped in the heart during early myocardial reperfusion.
- Early complement factor trapping may play a role in the pathogenesis of ischemia-reperfusion injury.
- Further research is needed to elucidate the precise mechanisms and clinical implications.
Abstract:
Accumulation of complement factors has been found to occur in the myocardium after infarction. We studied the possibility that the complement activation product C3a des-Arg is trapped within the coronary circulation during reperfusion of the ischemic myocardium. In 11 patients undergoing routine coronary artery bypass grafting, arterial blood was sampled before, during and after cardiopulmonary bypass. Blood was drawn from the coronary sinus concomitantly with arterial blood sampling 5 and 30 min after release of the aortic cross-clamp (n = 10). From a preoperative value of 92 +/- 13 ng/ml, C3a des-Arg rose during CPB to a maximum of 1816 +/- 393 at the end of CPB. Following reperfusion for 5 min, C3a des-Arg was 1284 +/- 232 ng/ml in arterial and 1106 +/- 100 in coronary sinus blood, a significant difference (p less than 0.05). The amount of C3a des-Arg trapped in the heart at 5-min reperfusion showed positive correlation with its arterial concentration (p less than 0.05). No significant difference was found after 30 min of reperfusion. Complement activation products trapped in the heart in the early reperfusion period may play a pathogenetic role in myocardial ischemia-reperfusion injury.