Abstract 1706: Elevation of Pericardial Fluid Active Matrix Metalloproteinase-9 (MMP-9) Level Is Closely Associated With Left Ventricular Remodeling

Abstract

Background: The development of congestive heart failure (CHF) is associated with left ventricular (LV) remodeling. However, fundamental mechanisms that contribute to this remodeling process remain unclear. The matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) have been demonstrated to play a significant role in tissue remodeling through a number of pathological processes. Objectives: The purpose of this study was to investigate whether MMPs and TIMPs represent autocrine/paracrine factors and are accumulated in pericardial fluid. We previously reported that active MMP-2 levels in pericardial fluid served as more sensitive and accurate indicators of LV remodeling than did active MMP-2 levels in plasma. Methods: We measured the concentrations of the enzyme (active MMP-9) in both plasma and pericardial fluid in 20 patients during coronary artery bypass graft surgery. Results: The active MMP-9 level was significantly higher in pericardial fluid than in plasma (4.68 ± 1.17 vs. 2.58 ± 0.29 ng/ml, p<0.0001). Interestingly, the pericardial fluid levels of active MMP-9 were significantly higher in patients with impaired LV function than in those with normal LV function (5.25 ± 0.57 vs. 2.96 ± 0.65 ng/ml, p<0.0001). Pericardial fluid active MMP-9 levels had closer relations with LVEDVI (r=0.459, p=0.047) and LVESVI (r=0.490, p=0.0321) than did plasma active MMP-9 levels (LVEDVI: r=0.065, p=NS; LVESVI: r=0.254, p=NS). Active MMP-9 levels in pericardial fluid but not in plasma inversely correlated with LV ejection fraction (r=−0.626, p=0.0033). Conclusions: Active MMP-9 levels in pericardial fluid serve as more sensitive and accurate indicators of LV remodeling than did active MMP-9 levels in plasma. Thus, active form of MMP-9 may be also secreted from the heart into the pericardial space with the progression of CHF, and it may have a pathophysiologic role in LV remodeling process as an autocrine/paracrine factor.