Figure 4.

Improvement in cytoplasmic Ca²⁺ transients, myocyte relaxation kinetics, SR Ca²⁺ content and basal cytoplasmic Ca²⁺ levels in failing cardiomyocytes following in vivo AAV9.SERCA2a gene transfer. A. Cytoplasmic Ca²⁺ transients (AMC (blue), HF (black), HF+SERCA2a (red)) measured from baseline corrected change in emitted fluorescence in fluo4-loaded myocytes stimulated at 0.5Hz (a), with overlain amplitude corrected traces demonstrating difference in Ca²⁺ transient decay kinetics (b), and quantitative comparison of time (ms) to 50% reduction from peak amplitude (R50) in myocytes paced at 0.5Hz (c). B. SR Ca²⁺ content in failing myocytes following SERCA2a gene therapy. Representative examples of traces of emitted fluorescence following application of caffeine to determine SR Ca²⁺ content, and quantitative measurement of SR Ca²⁺. Number of myocytes (n) studied: AMC n=9, HF n=12, HF+SERCA n=15. *p<0.05 *** p<0.001.