Procurement of human heart samples

The studies on human heart tissue were performed under the guidelines of the Declaration of Helsinki, with oversight by the Institutional Review Boards at The Ohio State University (protocol no. 2012H0197). Failing heart samples were obtained from patients who were diagnosed with end-stage heart failure and were receiving a heart transplant at The Ohio State University Wexner Medical Center. Non-failing hearts were obtained in collaboration with the Lifeline of Ohio Organ Procurement program from organ donors without diagnosed heart failure whose hearts were not suitable for transplantation. These donors died from causes other than heart failure. Hearts were removed from the patients/donors and immediately submersed in ice-cold cardioplegic solution containing 110 mM NaCl, 16 mM KCl, 16 mM MgCl₂^, 10 mM NaHCO₃, and 0.5 mM CaCl₂. Tissues were then flash-frozen in liquid nitrogen, and stored at −80°C until used for this study. Biopsies from the free wall of the left ventricle were used in this study.