Following severe heart failure, the heart’s ability to create new cells is quite limited. Nonetheless, when treated with a supportive heart pump, the previously damaged heart shows a remarkable improvement in its capacity to generate new muscle cells—surpassing even that of a healthy heart. This finding comes from a recent study conducted by the Karolinska Institutet in Sweden, published in the journal Circulation.
The human heart has a restricted ability to regenerate its muscle cells, known as myocytes. Researchers have previously been unaware of how this regenerative capability is affected when the heart suffers from severe heart failure.
Scientists at the Karolinska Institutet have now found that, after an injury, the pace of cell renewal is even slower than in a heart that is functioning normally. For patients with advanced heart failure, the common treatment involves a surgically implanted pump called a left ventricular assist device (LVAD), which aids in circulating blood.
Initiating the repair process
Interestingly, the researchers discovered that patients using such a heart pump, who have experienced considerable enhancements in their heart function, can regenerate heart muscle cells at a rate more than six times greater than that of healthy hearts.
“These findings hint at the possibility of an undiscovered mechanism that can activate the heart’s natural repair process,” states Olaf Bergmann, a lead researcher in the Department of Cell and Molecular Biology at Karolinska Institutet and the paper’s last author.
The underlying mechanism responsible for this effect remains unclear, and no current theories exist to clarify it.
“It’s challenging to pinpoint an explanation. The available data doesn’t provide clarity on the effect, but we aim to further investigate this process at both cellular and molecular levels,” explains Olaf Bergmann.
The results pave the way for creating new treatments for patients with serious heart issues that could enhance the heart’s ability to heal after injury, potentially reducing the reliance on heart transplants or other forms of long-term mechanical support.
“This provides a glimmer of hope that recovery from a heart incident may be improved in some way,” remarks Olaf Bergmann.
Assessing cell age
Determining the age of human cells and distinguishing between new and old cells is usually quite complex. However, by utilizing a method previously developed by Jonas Frisén, a professor of stem cell research at Karolinska Institutet, the research team has managed to measure the renewal rate of myocytes in the heart. This method is based on the observation that the level of radioactive carbon in the environment—and consequently in our cells—has gradually decreased since the nuclear test ban in 1963. Thus, newly formed cells contain slightly less radioactivity each year, allowing them to be effectively ‘dated.’
The study was conducted in close collaboration with Stavros Drakos from the University of Utah, USA, and received primary funding from the Swedish Research Council, the LeDucq Foundation, and the Ragnar Söderberg Foundation. No conflicts of interest have been reported.
