Increased plasma microfibrillar-associated protein 4 is associated with atrial fibrillation and more advanced left atrial remodelling

INTRODUCTION: This study aimed to evaluate the relationship of plasma microfibrillar-associated protein 4 (MFAP4) to atrial fibrillation (AF) and atrial structural remodelling. MATERIAL AND METHODS: Plasma MFAP4 levels were measured in 92 patients with AF (61 paroxysmal AF (PAF) patients and 31 persistent AF (PersAF) patients) and 71 control subjects without AF. Linear and logistic multivariate regression analyses were performed to determine the potential value of MFAP4 for predicting the incidence of AF and left atrial size. Then, plasma and atrial protein levels of MFAP4 and its association with atrial fibrosis ratio were analysed in an atrial-specific fibrosis rat model. RESULTS: There were significant differences in MFAP4 levels based on clinical group, with a gradient from control (1.71 ±0.53 ng/ml) to PAF (1.98 ±0.53 ng/ml) to PersAF (2.09 ±0.76 ng/ml) (p < 0.01). With multivariate analyses, plasma MFAP4 was found to be an independent determinant of left atrial diameter in AF patients. In atrial fibrosis rats, both plasma MFAP4 and atrial MFAP4 protein levels increased in atrial fibrosis rats and positively correlated with atrial fibrosis severity. CONCLUSIONS: Plasma MFAP4 was increased in patients with AF and was highest in those with PersAF; both plasma MFAP4 and atrial MFAP4 protein expression were directly associated with the extent of LA structural remodelling.