Atrial fibrillation was associated with significantly increased MMP-9 protein expression in atrial tissue compared to regular sinus rhythm (3.9 vs 1.5 ng/mg atrium).
Observational (n=38)
Absolute Event Rate: 3.9% vs 1.5%
p-value: p=<0.05
OBJECTIVES: The purpose of this study was to determine the relationship between matrix metalloproteinases (MMPs)-1, -2, and -9, and tissue inhibitors of metalloproteinases (TIMP)-1 and the atrial structural remodeling during atrial fibrillation (AF). BACKGROUND: Matrix metalloproteinases, a family of proteolytic enzymes and TIMPs, regulate the extracellular matrix turnover in cardiac tissue. METHODS: Tissue samples were obtained from 25 patients without a history of AF (regular sinus rhythm RSR) and 13 patients with AF (paroxysmal AF: 6, chronic AF 7) undergoing cardiac operations. We performed a western blotting analysis of the MMP-1, -2, and -9, and quantitatively analyzed the expression of the MMP-9 and TIMP-1 by real time polymerase chain reaction and ELISA. The localization of the MMP-9 was investigated by in situ zymography and immunohistochemistry. RESULTS: The active form of the MMP-9 was significantly increased in the AF group in comparison to that in the RSR group (p < 0.05), but there were no differences between the groups in the protein level of the latent form of the MMP-9 and active and latent forms of the MMP-1 and MMP-2. We also demonstrated that the expression of the MMP-9 was significantly more increased in the atria of the AF group than in that of the RSR group for both the messenger ribonucleic acid (mRNA) (AF: RSR; 1: 1.5) and protein levels (AF: RSR; 3.9 +/- 1.3 : 1.5 +/- 0.4 ng/mg atrium). The expression level of the MMP-9 was also higher in the PAF group than in the RSR group, however, the diameter of the left atrium was similar in both groups. The gelatinase activity and left atrium diameter were positively correlated (p < 0.05, R = 0.766). The relative expression of the mRNA for the monocyte chemoattractant protein-1 was higher in the AF group than in the RSR group. Immunohistochemical analysis revealed that the MMP-9 was distributed within the perivascular area and under the epicardium of the atria. CONCLUSIONS: We clearly showed that the expression of the MMP-9 increased in fibrillating atrial tissue, which may have contributed to the atrial structural remodeling and atrial dilatation during AF.
Nakano et al. (Fri,) conducted a observational in Atrial fibrillation (n=38). Atrial fibrillation vs. Regular sinus rhythm was evaluated on MMP-9 protein expression level (p=<0.05). Atrial fibrillation was associated with significantly increased MMP-9 protein expression in atrial tissue compared to regular sinus rhythm (3.9 vs 1.5 ng/mg atrium).