The hearts own stem cells play their part in regeneration

Sca1 stem cells replace steadily ageing heart muscle cells

November 28, 2013

Up until a few years ago, the common school of thought held that the mammalian heart had very little regenerative capacity. However, scientists now know that heart muscle cells constantly regenerate, albeit at a very low rate. Researchers at the Max Planck Institute for Heart and Lung Research in Bad Nauheim, have identified a stem cell population responsible for this regeneration. Hopes are growing that it will be possible in future to stimulate the self-healing powers of patients with diseases and disorders of the heart muscle, and thus develop new potential treatments.

Stem cells play a part in heart regeneration. This image of the fluorescence microscope depicts a section of the heart tissue of a mouse. The green colouring of the cells in the middle shows that the cell originated from a so-called Sca1 stem cell.

MPI for Heart and Lung Research

MPI for Heart and Lung Research

Some vertebrates seem to have found the fountain of youth, the source of eternal youth, at least when it comes to their heart. In many amphibians and fish, for example, this important organ has a marked capacity for regeneration and self-healing. Some species in the two animal groups have even perfected this capability and can completely repair damage caused to heart tissue, thus maintaining the organs full functionality.

The situation is different for mammals, whose hearts have a very low regenerative capacity. According to the common school of thought that has prevailed until recently, the reason for this deficit is that the heart muscle cells in mammals cease dividing shortly after birth. It was also assumed that the mammalian heart did not have any stem cells that could be used to form new heart muscle cells. On the contrary: new studies show that aged muscle cells are also replaced in mammalian hearts. Experts estimate, however, that between just one and four percent of heart muscle cells are replaced every year.

Scientists in Thomas Brauns Research Group at the Max Planck Institute for Heart and Lung Research have succeeded in identifying a stem cell population in mice that plays a key role in this regeneration of heart muscle cells. Experiments conducted by the researchers in Bad Nauheim on genetically modified mice show that the Sca1 stem cells in a healthy heart are involved in the ongoing replacement of heart muscle cells. The Sca-1 cells increase their activity if the heart is damaged, with the result that significantly more new heart muscle cells are formed.

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