Injection of heart stem/progenitor cells directly into the heart is one approach being developed as a way to improve heart function following heart attack.

Now, a team of researchers, at Tokyo Women's Medical University, Japan, and Chiba University Graduate School of Medicine, Japan, has found that transplanting sheets of clonally expanded heart cells expressing the protein Sca-1 (cells that are heart stem/progenitor cells and that the authors term CPCs) improves heart function after a heart attack in mice.

The team, led by Katsuhisa Matsuura and Issei Komuro, found that CPCs not only formed heart muscle cells but also secreted a soluble molecule (sVCAM-1) that induced the migration of endothelial cells (which help form new blood vessels) and CPCs and prevented heart muscle cells dying from oxidative stress. In the mouse model of heart attack, preventing sVCAM-1 from binding to the protein VLA-4 inhibited the formation of new blood vessels and blocked CPC migration and survival, leading to a decreased ability of the transplanted CPC sheets to improve heart function. The authors conclude that these data provide new insight into the mechanisms by which heart stem/progenitor cells improve heart function following heart attack.