Researchers here demonstrate one of a number of approaches to instruct native cells to regenerate more tissue damage than would otherwise have taken place, in this case by delivering a specific microRNA molecule that regulates patterns of gene expression and as a result increases bone regrowth. This is of interest beyond the repair of injuries, as bone mass and strength are progressively lost over the course of aging to produce the condition known as osteoporosis; compensating for this loss will reduce frailty in old age. As the scientific community becomes ever more proficient at cellular programming, this sort of therapy will likely replace the present state of the art in stem cell transplants. Stem cell therapies largely work because the newly introduced cells deliver signals to native cells, but if all of those signals were known and their effects on cells fully understood, the stem cells would not be necessary to achieve beneficial results.
Scientists have developed a polymer sphere that delivers a molecule to bone wounds that tells cells already at the injury site to repair the damage. Using the polymer sphere to introduce the microRNA molecule (miRNA-26a) into cells elevates the job of existing cells to that of injury repair by instructing the cells' healing and bone-building mechanisms to switch on. Using existing cells to repair wounds reduces the need to introduce foreign cells - a very difficult therapy because cells have their own personalities, which can result in the host rejecting the foreign cells, or tumors. The microRNA is time-released, which allows for therapy that lasts for up to a month or longer.
The technology can help grow bone in people with conditions like oral implants, those undergoing bone surgery or joint repair, or people with tooth decay. "The new technology we have been working on opens doors for new therapies using DNA and RNA in regenerative medicine and boosts the possibility of dealing with other challenging human diseases." It's typically very difficult for microRNA to breach the fortress of the cell wall, but the polymer sphere easily enters the cell and delivers the microRNA. Bone repair is especially challenging in patients with healing problems, but researchers were able to heal bone wounds in osteoporotic mice. Millions of patients worldwide suffer from bone loss and associated functional problems, but growing and regenerating high-quality bone for specific applications is still very difficult with current technology. The next step is to study the technology in large animals and evaluate it for use in humans.