Glial cells, which can be found in the nervous system, play an important role for normal function and development. Based on the main function, they are divided into subtypes, including astroglia, microglia, and ensheathing glia.
A recent study has discovered a new form of glial cell in the heart, which would help explain several cardiac diseases and congenital abnormalities. The findings were published in PLOS Biology by scientists from the University of Notre Dame in Indiana, the United States. Using tissue from humans, mice, and zebrafish, the group of authors highlighted an area of the heart that shelters these cells. The discovery was consistent across different species.
In general, neuronal cells in the central nervous system precede those in the autonomic nervous system and peripheral nervous system. Therefore, the scientists looked for the origin of these cells before they penetrate the heart. With the zebrafish model, they verified that glial cells were originated from the neural crest in the hindbrain. The glial cells started moving into the heart after 1 day of fertilization of the embryos. Within 4 days, they had populated a heart region called the outflow tract.
To confirm the hypothesis that glial cells control autonomic functions of the heart, the scientists removed the cells across different species. The removed samples, on average, had increased heart rates of around 20 bpm. This is also known as ventricular tachycardia.
Because ventricular tachycardia happens when ionic activity in the outflow tract is imbalanced, the researchers wanted to find out whether the main cause is the lack of cardiac nexus glia in the area. To test it, the authors removed cardiac nexus glia in other areas, especially the atrium. The result showed that no special effects on overall heart rate. This verifies the significant of cardiac nexus glia in the outflow tract.
It is worth noting that around 30 percent of congenital heart abnormalities is directly associated with outflow tract dysfunction. Nevertheless, it is still unknown whether this is particularly because of a deviance of cardiac nexus glia in the process of development.
In spite of these new experimental results on cardiac function and astroglial manipulation, whether it translates to heart issues in humans is still unclear. The scientists believe that it may be a complicated interaction of lifestyle and genetic factors. Therefore, further research is needed to learn more about these links.
Source:
https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001444
