Washington, Nov 28 (ANI): A new study has reported the first functional evidence that heart cells derived from human embryonic stem cells exhibit one of the most critical properties of mature adult heart cells, an important biological process called excitation-contraction coupling.

The study, led by Ronald Li, an associate professor of cell biology and human anatomy at UC Davis School of Medicine, observed cells that had begun the maturation process toward becoming heart cells.

Previous experiments were able to derive heart cells from human embryonic stem cells. But those cells always remained too immature to be of any therapeutic use and actually could cause lethal arrhythmias in animal models, said Li.

Now, what weve been able to do is push the therapeutic potential of human embryonic stem cells further so that eventually they might be used safely, and with enhanced efficacy, in transplantation cases, he said.

The main function of the heart is to mechanically pump blood in a highly coordinated fashion throughout the body.

To do this, heart cells must receive electrical signals and contract in response to those signals. This link, called the excitation-contraction coupling, is dependent on the cells ability to move calcium ions across an internal organelle known as sarcoplasmic reticulum, or the so-called calcium store.

The ability to handle calcium is disrupted in the cells of patients who experience heart failure.

In the study, the researchers took human embryonic stem cells and grew them in cultures, allowing them to differentiate, or develop, into heart cells.

Once they had these tiny, pulsing masses, the investigators energized the cells with small amounts of electrical current and chemicals, including caffeine.

Then, they measured how the amount of intracellular calcium changed and looked for the presence of proteins and cellular structures known to be involved in excitation-contraction coupling.

The analysis found evidence of the functional calcium stores for excitation-contraction coupling.

For future stem cell based therapies to work, scientists will need to have heart cells that exhibit mature excitation-contraction coupling. The current study found protein functions, which were involved in the early stages of this coupling process.

Our latest study gives us great hope of eventually achieving a breakthrough where stem cell therapy could be used in the types of cases that today require a heart transplant, Li said.

The study is published in the journal Stem Cells. (ANI)