Fig. 4.

Effect of recombinant PCSK9 on cell shortening in the presence of Pep 2–8 or alirocumab. Adult rat ventricular cardiomyocytes were cultured under serum-free conditions and incubated with recombinant PCSK9 (200 ng/ml), the PCSK9 inhibitor Pep 2–8 (10 µM), the monoclonal PCSK9 antibody alirocumab (1.5 mg/ml) and combinations thereof. After 24 h load free cell shortening was measured (cells were paced at 2 Hz) and expressed as (a) ΔL/L (%), (b) contraction velocity (µm/s) and c relaxation velocity (µm/s) of Control = 278, PCSK9 = 262, Pep 2–8 = 114, PCSK9 + Pep = 111, Alirocumab = 147 and PCSK9 + Aliro. = 48 cells (5–20 independent experiments with intraassay variability of p > 0.05). Statistical analysis was performed by one-way ANOVA and Student–Newman–Keuls for post hoc analysis. *p ≤ 0.05 vs. Control, Pep 2–8, PCSK9 + Pep, Alirocumab and PCSK9 + Aliro. Data are mean ± SD