Cardiac resynchronization therapy-induced left ventricular reverse remodelling is associated with reduced plasma annexin A5

Cardiac resynchronization therapy (CRT) diminishes cardiac apoptosis and improves systolic function in heart failure (HF) patients with ventricular dyssynchrony. Plasma annexin A5 (AnxA5), a protein related to cellular damage, is associated with systolic dysfunction. We investigated whether the response to CRT is associated with plasma AnxA5. We also studied AnxA5 overexpression effects in HL-1 cardiomyocytes. AnxA5 ELISA was performed in plasma from 57 patients with HF and ventricular dyssynchrony at baseline and after 1 year of CRT. Patients were categorized as responders if they presented both a reduction in left ventricular (LV) end-systolic volume index (LVESVi) > 10% and an increase in LV ejection fraction (LVEF) > 10%. HL-1 cells were transfected with human AnxA5 cDNA, and AnxA5, PKC, Akt, p38MAPK, Bcl-2, mitochondrial integrity, caspase-3, and ATP were assessed. At baseline, an increased plasma AnxA5 level was associated with decreased LVEF and increased LVEDVi values (P < 0.05). No differences in baseline AnxA5 were observed between responders and non-responders. After CRT, AnxA5 decreased (P = 0.001) in responders but remained unchanged in non-responders. Final values of AnxA5 were independently associated with LVEF (r = -0.387, P = 0.003) and LVESVi (r = 0.403, P = 0.004) in all patients. Compared with control cells, AnxA5-transfected cells exhibited AnxA5 overexpression, decreased PKC and Akt and increased p38MAPK and Bcl-2 phosphorylation, loss of mitochondrial integrity, caspase-3 activation, and decreased ATP. CRT-induced LV reverse remodelling is associated with reduction in plasma AnxA5. The excess of AnxA5 is detrimental for HL-1 cardiomyocytes. Collectively, these data suggest that the beneficial effects of CRT might be related to an AnxA5 decrease.