Relationship betweenα-SMA and atrial fibrosis in patients with valvular atrial fibrillation / 西安交通大学学报(医学版)

ABSTRACT

Objective To investigate the expression of α-smooth muscle actin (α-SMA)in patients with valvular atrial fibrillation and study the relationship betweenα-SMA and atrial fibrosis in patients with valvular atrial fibrillation (AF).Methods For this study we enrolled 84 consecutive patients with rheumatic heart disease who were to receive cardiac surgery.The patients were divided into AF group (AF,n=39)and sinus rhythm group (SR, n=45).Their clinical data including baseline demographics,routine laboratory test and echocardiographics were collected before surgery.The right atrial tissue (0 .3-0 .5 cm3 )was disserted during the surgery.Right atrial fibrosis was observed by Masson staining.The mRNA expression ofα-SMA in atrial tissue were determined by Real-time quantitative PCR.Western blot was used to measure the protein expression ofα-SMA in atrial tissue.Results The two groups did not significantly differ in sex ratio,age,blood pressure,blood biochemical indicators or other aspects of medical history (P>0.05).However,left and right atrium diameters in AF group were significantly larger than those in SR group (P<0 .05 ).Masson staining suggested that collagen volume fraction and collagen content were significantly higher in AF group than in SR group (P<0 .05 ).The mRNA and protein expressions ofα-SMA in right atrial tissue were obviously higher in AF group than in SR group (coefficients P<0 .05 ).The mRNA and protein expressions ofα-SMA from right atrial tissue in the 84 patients were positively correlated with collagen content (coefficients of 0.587 and 0.607;P=0.029,0.014,respectively).Conclusion There is significant atrial fibrosis in patients with valvular atrial fibrillation,which is closely related to up-regulated expression ofα-SMA gene.