Around 610,000 people die from heart disease in the U.S. every year – that’s one in every four deaths. It’s proving to be a particularly difficult medical problem: Damage to the heart is almost always irreversible, as heart cells cannot regenerate themselves.
This crippling lack of regeneration, however, could soon be a thing of the past, as researchers have discovered how to make a remarkable new type of cell that may allow hearts to repair themselves. The new study, published in the journal Cell Stem Cell, reveals that these transplantable cells are produced using a revolutionary new technique, which allows researchers to temporarily “freeze” a stem cell in its development.
Heart failure (HF), wherein the heart is overworked or the supply of oxygenated blood to it is too low, causes a huge loss of heart muscle cells known as cardiomyocytes (CMs). “You lose at least a billion heart cells in one heart attack,” Dr. Sheng Ding, a professor at the Gladstone Institute of Cardiovascular Disease and coordinating author of the study, told IFLScience.
Not only can these CMs not be regenerated by the heart, but they cannot even be replaced by new injected CMs. “Transplanted new heart cells into the patient’s heart don’t survive – within a day or two, most are lost,” Ding said.
Ding’s team thought that one potential way to overcome this issue would be to use cells called “progenitors.” Although similar to a pluripotent stem cell, which can become any cell found in the human body, these progenitor cells are somewhat differentiated, namely they are already programmed to become a specific target cell – including heart cells.
Three types of key heart cells made using the new CPCs: the cardiomyocytes (for heart muscles) and the endothelial and vascular smooth muscle cells (to make blood vessels). Ding et al./Cell Stem Cell
Cardiovascular progenitor cells (CPCs) are naturally produced as the heart forms within the embryo, and they go on to form all necessary heart cell types, including CMs. Using a cocktail of pharmaceutical drugs, they were able to produce these CPCs in the lab from stem cells, halting their natural development into fully functioning heart cells. These lab-made cells are known as “induced expandable CPCs.”
Not only can these CPCs be induced to become new heart cells, but they can replicate indefinitely, potentially meaning that damaged hearts can be injected with self-repairing biological material. In order to test their theory, a solution containing these CPCs – “locked in” to becoming various types of heart cells – were injected into a mouse after it had suffered from a heart attack.
Incredibly, 90 percent of these new cells spontaneously transformed into functioning heart cells, creating new blood vessels and generating new muscular tissue. Compared to the injection of stem cells, which require a complex series of signals to begin developing into heart cells, this is a huge improvement.
Heart function was improved in the mouse for at least three months. As the original stem cells were sourced from skin cells, this raises a tantalizing future possibility: A patient’s own skin cells could be used to treat their own heart disease.
“I predict that in the next couple of years we will be able to make human CPCs in a very similar manner,” Sheng said. “Human trials will follow after that.”