Using a new cell-lineage tracing technique they devised, regenerative medicine researchers at the University of Texas Southwestern Medical Center and from the University of Tsukuba have identified a cell that replenishes adult heart muscle.

Adult heart muscle is comprised of cells called cardiomyocytes. Most cardiomyocytes don't replenish themselves after a heart attack or other significant heart muscle damage. Dr. Wataru Kimura from the University of Tsukuba and Dr. Hesham Sadek from the University of Texas Southwestern Medical Center were able to devise a new cell-tracing technique, allowing them to detect cells that do replenish themselves after being damaged.

Their research team identified a cell that generates new heart muscle cells. That cell does not appear to be a stem cell, but rather a specialized cardiomyocyte, or heart muscle cell, that can divide, which the majority of cardiomyocytes cannot do. Previous research by them revealed that it is the highly oxygenated environment of the heart that prevents most heart muscle cells from dividing. They reasoned that the cells that do divide must, therefore, be low on oxygen, which is a condition called hypoxic. They then devised a technique to identify and trace the lineage of hypoxic cells. That technique led them to the identification of the proliferating cells within heart muscle.

For decades, researchers have been trying to find the specialized cells that make new muscle cells in the adult heart. The researchers think that they have found that cell. Their study has appeared online in Nature.

Their discovery opens up a novel mechanism of cell-cycle control in cardiac myocytes and lends credence to the potential for regenerating - rebuilding - the diseased heart.

Original Paper

Wataru Kimura, Feng Xiao, Diana C. Canseco, Shalini Muralidhar, SuWannee Thet, Helen M. Zhang, Yezan Abderrahman, Rui Chen, Joseph A. Garcia, John M. Shelton, James A. Richardson, Abdelrahman M. Ashour, Aroumougame Asaithamby, Hanquan Liang, Chao Xing, Zhigang Lu, Cheng Cheng Zhang & Hesham A. Sadek, Hypoxia fate mapping identifies cycling cardiomyocytes in the adult heart, Nature 523, 226-230 (09 July 2015) doi:10.1038/nature14582