Effects of matrix metalloproteinase-1,9 and tissue inhibitor-1 of metalloproteinase expression on human atrial structural remodeling during atrial fibrillation

Objective To determine the relationship between matrix metalloproteinase-1(MMP-1),MMP-9,tissue inhibitors of metalloproteinases(TIMP)-1 and the atrial structural remodeling during atrial fibrillation(AF).Methods The right atrial tissue samples were obtained from 8 patients without a history of AF,8 patients with paroxysmal AF and 12 patients with persistent AF undergoing heart valve replacement surgery for rheumatic heart diseases.mRNA levels of MMP-1,MMP-9 and TIMP-1 were measured by semi-quantitative reverse transcription polymerase chain reaction(RT-PCR).Results(1)The mRNA level of MMP-1 was increased in the paroxysmal AF group in comparison to the sinus rhythm group but no statistics difference.It increased significantly in the persistent AF group(P0.05) compared with the sinus rhythm.(2)In the sinus rhythm group,paroxysmal AF group and persistent AF group,the mRNA level of MMP-9 was significantly increased in turn(P0.05) in the three groups.The expression of MMP-9 mRNA was positively correlated with AF duration and the left atrial diameter(r=0.509,0.543,P0.01).(3)TIMP-1 expression at mRNA level was down-regulated in the paroxysmal AF and persistent AF groups(P0.05,P0.01).The expression of TIMP-1 mRNA was negatively correlated with AF duration and the left atrial diameter(r=-0.43,-0.387,P0.05).Conclusion The up-regulation of MMP-1,MMP-9 mRNA level,along with the down-regulation of TIMP-1 mRNA level may contributed to the atrial structural remodeling.