As the body develops over time, nearly all of the heart's regeneration mechanisms become inactive. Consequently, after a heart attack, dead cardiac cells do not redevelop. Instead, dead cardiac muscle tissue is replaced by inactive scar tissue, which permanently weakens the functionality of the heart and often damages quality of life.
In response to this problem, scientists have attempted to create heart patches made of fibers on which new cardiomyocytes, or heart cells, can grow. Thus far, all the fibers tested have not been able to support cell growth. However, recent research conducted at Max Planck's Institute for Heart and Lung Research suggests that silk from silkworm could serve as the best scaffold for cardiomyocytes.
Researchers used the cocoon from the tasar silkworm to produce coin-sized disks as a surface for the heart cells to grow. In contrast to other fibers such as fibrin, nanofiber, gold nanowires and polymer that are often brittle and subject to imminent attack by the immune system, the coarseness and the adhesive qualities of silk make it an ideal surface for muscle cell growth.
Additionally, silkworm silk contains specific proteins which permit bonding of cardiomyocytes to its exterior. When the silk was used in a test at the Max Planck Institute, rat heart cells that attached to its surface remained functional and beat in unison for 20 days. Furthermore, investigators are currently exploring the possibility of converting stem cells to heart cells as a means of obtaining human heart cells for growth.
The silk's clinical application is still under investigation because of the risks involved in procuring safe quantities of heart cells from patients. Nevertheless, the discovery of silkworm silk for regeneration of heart tissue ends the long and exhaustive hunt for an alternative method of growing heart cells. The use of silkworm silk in the heart could potentially maximize heart functionality during the human lifespan and is considered a breakthrough in the cardiac world.
