Recently, researchers have healed broken and injured hearts of live mice by reactivating long dormant molecular machinery generally present in the animals tissue and their body.The study has been conducted by Salk Institute for Biological Studies (US) that has helped find the way to fresh solutions for heart disorders revealed in human beings, however adult mammals don’t normally recreate damaged tissue, they may hold back a latent ability as a holdover from development like their far off ancestors on an evolutionary tree.
When the Salk researchers blocked four molecules thought to suppress these programs for regenerating organs, they saw a drastic improvement in heart regeneration and healing in the mice.
Study’s senior author Juan Carlos Izpisua Belmonte, a professor in the Gene Expression Laboratory at Salk said that organ regeneration is a fascinating phenomenon that seemingly recapitulates the processes observed during development. However, despite their current understanding of how embryogenesis and development proceeds, the mechanisms preventing regeneration in adult mammals have remained elusive.
Their studies uncovered four molecules in particular that fit the criteria. They are MiR-99, MiR-100, Let-7a and Let-7c. All were heavily repressed during heart injury in zebrafish and they were also present in rats, mice and humans.
However, in studies of mammalian cells in a culture dish and studies of living mice with heart damage, the group saw that the levels of these molecules were high in adults and did not decline with injury. So the team used adeno-associated viruses specific for the heart to target each of those four microRNAs, suppressing their levels experimentally.
Injecting the inhibitors into the hearts of mice that initially suffered a heart attack triggered the recreation of cardiac cells, enhancing numerous physical and functional aspects of the heart, like thickness of its walls and its ability to generate and pump blood.
The scarring caused due to the heart attack has been minimized with solutions to controls, the scientists and researchers found that the improvements were quite obvious three and six months post treatment phase which is unusually longer time in a mouse’s life.