Oxidized Low-Density Lipoprotein Associates with Ventricular Stress in Young Adults and Triggers Intracellular Ca2+ Alterations in Adult Ventricular Cardiomyocytes

Figures

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  Figure 1. Serum biomarkers in a young population with and without previous cardiovascular disease. Serum levels of biomarkers in subjects with high-lifetime cardiovascular risk (LT-CVR), low-lifetime cardiovascular risk (LT-CVR) or stable coronary artery disease (SCAD). (A) C-reactive protein (CRP). (B) N-terminal pro-B-type natriuretic peptide (NT-proBNP). (C) Oxidized LDL (oxLDL). (D) Correlation analysis of oxLDL and NT-proBNP. * p < 0.05, ** p < 0.01, *** p < 0.001 versus low LT-CVR; # p < 0.05, ### p < 0.001 versus high LT-CVR.

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  Figure 2. Acute effects of oxLDL on Ca2+ transients. (A) Representative line-scan images (upper panels) and fluorescent profile (lower panel) of a cardiomyocyte perfused with vehicle (upper left and dotted black line) and after perfusion of 10 µg/mL oxLDL (upper right and continuous grey line) under 1 Hz field stimulation. Mean values of Ca2+ transients amplitude (F/F0, B), peak (F, C) baseline (F0, D), decay time constant (time constant of fitting the descending trace of the fluorescence to an exponential function) (tau, E), and time-to-peak (F). (n = 32 cells, N = 5 rats). * p < 0.05, *** p < 0.001 versus vehicle-treated cardiomyocytes.

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  Figure 3. Acute effects of oxLDL on sarcoplasmic reticulum-Ca2+ load. (A) Representative line-scan images of a cardiomyocyte perfused with vehicle (upper panel) or with 10 µg/mL oxLDL (lower panel) under 1 Hz field stimulation and in the presence of caffeine. Mean values of caffeine-induced Ca2+ transients amplitude (F/F0, B) and decay time constant after caffeine perfusion (tau, C) in cardiomyocytes treated with vehicle (n = 17 cells, N = 5 rats) or 10 µg/mL oxLDL (n = 20 cells, N = 5 rats). *** p < 0.001 versus vehicle-treated cardiomyocytes.

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  Figure 4. Acute effects of oxLDL on diastolic Ca2+ leak. (A) Representative line-scan images of Ca2+ sparks in a cardiomyocyte perfused with vehicle (upper panel) or 10 µg/mL oxLDL (lower panel). Mean values of Ca2+ spark frequency (B) and spark-mediated Ca2+ leak (C) (n = 21 cells, N = 5 rats). ** p < 0.01 versus vehicle-treated cardiomyocytes.

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  Figure 5. Pro-arrhythmogenic effect of oxLDL in vitro. (A) Representative line-scan images of Ca2+ waves in a cardiomyocyte perfused with vehicle (left panel) or 10 µg/mL oxLDL (right panel). (B) Ca2+ wave frequency (n = 21 cells, N = 5 rats). * p < 0.05 versus vehicle-treated cardiomyocytes.