Myocardial ischemia enhances the expression of acidic fibroblast growth factor in human pericardial fluid

Acidic fibroblast growth factor (FGF) is a potent mitogen that can induce angiogenesis in vivo. We have recently reported a marked increase of basic FGF in the pericardial fluid of patients with severe coronary stenosis and an increase in vascular endothelial growth factor (VEGF) in the pericardial fluid of patients with severe myocardial ischemia. The purpose of this study was to evaluate whether acidic FGF levels in the pericardial fluid are associated with severe myocardial ischemia. Immediately after incision of the pericardium in 48 patients during open-heart surgery, 3-5ml of pericardial fluid was obtained. Concentrations of basic FGF and VEGF in the pericardial fluid were measured using an enzyme-linked immunosorbent assay (ELISA). The ELISA system for human acidic FGF was newly developed using a rabbit antibovine acidic FGF antibody. The patients were divided into three groups (group A: 13 patients undergoing emergency coronary artery bypass grafting (CABG) for unstable angina; group B: 17 patients undergoing elective CABG for stable angina; group C: 18 patients undergoing nonischemic open-heart surgery). The VEGF level in the pericardial fluid in group A was 68 +/- 59pg/ml, which was significantly higher than 33 +/- 9 pg/ml in group B and 31 +/- 20 pg/ml in group C (P < 0.05). The concentrations of basic FGF in the pericardial fluid in groups A and B were 722 +/- 601 and 773 +/- 763pg/ml, respectively, significantly higher than 263 +/- 349pg/ml in group C. The pericardial acidic FGF level in group A was 4,291 +/- 2,336 pg/ml, which was also significantly higher than 2,386 +/- 1,048 pg/ml in group B and 2,589 +/- 990 pg/ml in group C (P < 0.05). The acidic FGF level correlated well with the level of VEGF (r = 0.61, P < 0.0001). It is concluded that the level of acidic FGF in pericardial fluid is associated with severe myocardial ischemia. This result indicates that the release of acidic FGF from the myocardial tissue into pericardial fluid is closely related to severe myocardial ischemia.