Qiliqiangxin Capsule Modulates Calcium Transients and Calcium Sparks in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

BACKGROUND

The therapeutic effects of Qiliqiangxin capsule (QLQX), a Chinese patent medicine, in patients with chronic heart failure are well established. However, whether QLQX modulates cardiac calcium (Ca) signals, which are crucial for the heart function, remains unclear. . This study aimed to evaluate the role of QLQX in modulating Ca signals in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs).

MATERIALS AND METHODS

Fluorescence imaging was used to monitor Ca signals in the cytosol and nuclei of hiPSC-CMs. For Ca spark measurements, the line-scan mode of a confocal microscope was used.

RESULTS

The QLQX treatment substantially decreased the frequency of spontaneous Ca transients, whereas the amplitude of Ca transients elicited by electrical stimulation did not change. QLQX increased the Ca spark frequency in both the cytosol and nuclei without changing the sarcoplasmic reticulum Ca content. Interestingly, QLQX ameliorated abnormal Ca transients in CMs differentiated from hiPSCs derived from patients with long-QT syndrome.

CONCLUSIONS

Our findings provide the first line of evidence that QLQX directly modulates cardiac Ca signals in a human cardiomyocyte model.