Growing mature cardiomyocytes – heart muscle cells – from embryonic stem cells in vitro has proved problematic for researchers. While cardiomyocytes can be grown, those cells do not mature in an artificial environment. The process of maturation in humans takes decades and the signals required are complex. So far, researchers have been unable to replicate those signals in vitro.
However, there is an alternative. Growing immature cells and introducing them into the heart and allowing them to mature in vivo. Researchers at Johns Hopkins University School of Medicine’s Institute for Cell Engineering have done just that.
The researchers showed that immature cardiomyocytes can be injected into the hearts of newborn rats where the maturation process then takes place.
For the study the team developed cardiomyocytes from embryonic stem cells of mice and injected around 200,000 of the immature cells into the hearts of newborn rats. To prevent rejection of the new cells, the team used rats that had been engineered without an immune system. After around a month, the introduced cells appeared to have matured into healthy, adult cardiomyocytes. The team also demonstrated that the heart cells could function as normal, adult cardiomyocytes.
According to Chulan Kwon, lead researcher for the study, “Our concept of using a live animal host to enable maturation of cardiomyocytes can be expanded to other areas of stem cell research and really opens up a new avenue to getting stem cells to mature.”
The maturation technique has only been shown to be effective in rats and the research is still in the early stages, but the researchers believe there is significant potential for in vivo matured cardiomyocytes to be used in the treatment of heart disease. Stem cells could be harvested from patients, differentiated into cardiomyocytes, and then injected into the hearts of patients suffering from heart disease.
Further research is needed and a human trial using a similar technique is likely to be many years off, although the researchers hope that their work could lead to significant advances in precision medicine.
The study – Neonatal Transplantation Confers Maturation of PSC-Derived Cardiomyocytes Conducive to Modeling Cardiomyopathy – has recently been published in Cell Reports.