In a landmark study done at Duke University Medical Center by a team headed by researcher Victor Dzau, M.D., microRNA was successfully used for regenerating scarred heart tissue and turning it back into working muscle. The concept had previously been tested in cells in a petri dish, but this experiment broke new ground by healing scarred hearts in living mice.
MicroRNA Conducts the Symphony of Cell Development
MicroRNA (abbr. miRNA) is a type of genetic molecule found in the cells of all plants and animals that regulates the expression of genes after they have been transcribed by RNA; DNA is the blueprint for cellular development. RNA is the molecule that moves the amino acids into place, and miRNA orchestrates the expression of the resulting genes by turning sections off or on.
MiRNA has frequently been observed in earlier experiments effecting genes by repressing their expression. In this latest research, miRNA turned on cardiac genes resulting in the conversion of fibroblast scar tissue back into functional muscle. This confirms the potential of using miRNA to regenerate not only hearts but scar tissue and cell damage of other kinds.
There are as many as one thousand different types of miRNA molecules in the human gene pool. Each one only works with a specific cell type. In the Duke University study, researchers isolated four kinds of cardiac miRNA from mice and then injected them directly into mice with damaged hearts. Over time, the damaged cardiac cells regenerated and began working again.
The presence and function of miRNA has only been established since the early 2000s. The potential therapeutic uses for this molecule were recognized early on, and this experiment confirms an important concept that will, no doubt, be explored and developed in the future.
Researcher Dzau said in a press conference after the publication of the study in the journal Circulation Research on April 26, 2012 that he expects to see human applications within the next ten years. He and his team will now work on applying miRNA therapy in other animals and finally humans.
Will MicroRNA Head Off Stem Cell Debate?
The use of miRNA for cellular regeneration is also important because it does not involve stem cells which can also produce similar results but have technical and ethical problems. Stem cells can cause other genetic alterations besides the ones they are designed to accomplish, and there is controversy over how stem cells are obtained.
The results of this study seem to be pointing a way toward many future breakthroughs for people recovering from heart attacks, strokes, nerve damage and many other diseases and conditions that involve scarring and loss of tissue function. MicroRNA might be the cellular messenger that fast-forwards medicine beyond some of the thorny ethical dilemmas of stem cell research and ushers in a new method of healing damaged hearts and more.