Single histidine-substituted cardiac troponin I confers protection from age-related systolic and diastolic dysfunction.

Aims: Contractile dysfunction associated with myocardial ischaemia is a significant cause of morbidity and mortality in the elderly. Strategies to protect the aged heart from ischaemia-mediated pump failure are needed. We hypothesized that troponin I-mediated augmentation of myofilament calcium sensitivity would protect cardiac function in aged mice.

Cardiac-directed parvalbumin transgene expression in mice shows marked heart rate dependence of delayed Ca2+ buffering action.

Relaxation abnormalities are prevalent in heart failure and contribute to clinical outcomes. Disruption of Ca2+ homeostasis in heart failure delays relaxation by prolonging the intracellular Ca2+ transient. We sought to speed cardiac relaxation in vivo by cardiac-directed transgene expression of parvalbumin (Parv), a cytosolic Ca2+ buffer normally expressed in fast-twitch skeletal muscle.

Nkx2.5 homeoprotein regulates expression of gap junction protein connexin 43 and sarcomere organization in postnatal cardiomyocytes.

Nkx2.5, an evolutionarily conserved homeodomain containing transcription factor, is one of the earliest cardiogenic markers. Although its expression continues through adulthood, its function in adult cardiomyocytes is not well understood.

Long-term improvement of cardiac function in rats after infarction by transplantation of embryonic stem cells.

Objective: This study was designed to investigate the feasibility of and potential functional improvement with embryonic stem cell transplantation in rats 32 weeks after myocardial infarction.

Methods: Before cell transplantation, cultured embryonic stem cells were transfected with the complementary DNA of green fluorescent protein to identify engrafted cells in myocardium. Myocardial infarction was induced by ligation of the left coronary artery.

Significant improvement of heart function by cotransplantation of human mesenchymal stem cells and fetal cardiomyocytes in postinfarcted pigs.

Background: Viable cardiomyocytes after myocardial infarction (MI) are unable to repair the necrotic myocardium due to their limited capability of regeneration. The present study investigated whether intramyocardial transplantation of human mesenchymal stem cells (hMSCs) or cotransplantation of hMSCs plus human fetal cardiomyocytes (hFCs; 1:1) reconstituted impaired myocardium and improved cardiac function in MI pigs.

Methods And Results: Cultured hMSCs were transfected with green fluorescent protein (GFP).

Transplantation of embryonic stem cells improves cardiac function in postinfarcted rats.

Massive loss of cardiac myocytes after myocardial infarction (MI) is a common cause of heart failure. The present study was designed to investigate the improvement of cardiac function in MI rats after embryonic stem (ES) cell transplantation. MI in rats was induced by ligation of the left anterior descending coronary artery.