A sizable portion of signaling between cells is carried by vesicles, tiny packages of secreted molecules wrapped in a membrane. Investigations of the effects of early stem cell therapies have revealed that in many cases whatever benefits are realized must be produced by signals that induce behavioral changes in native cells, since the transplanted cells die quite quickly. Now researchers are beginning to look at harvesting or manufacturing suitable vesicles as a way to recreate some of the beneficial effects of cell transplantation, a path that bypasses the need to create patient-matched cells or otherwise deal with immune rejection issues. This part of the field is at a very early stage, but nonetheless examples such as the study here are emerging:
A recent paper describes a new approach to bone regeneration; stimulating cells to produce vesicles which can then be delivered to facilitate tissue regeneration. The researchers believe that the findings mark the first step in a new direction for tissue regeneration with the potential to help repair bone, teeth and cartilage. Current approaches have significant limitations; autologous grafts cannot meet demand and cause patient morbidity, allogeneic bone lacks bioactive factors, and growth factor-based approaches (e.g. BMP-2) may have serious side-effects and high costs. Consequently, there is a considerable need to devise new methods for the generation of large volumes of bone without associated patient morbidity.
In recent years, attention has been focused on cell-based approaches. However, translation is frequently prevented by insurmountable regulatory, ethical and economic issues. This novel solution delivers all the advantages of cell-based therapies but without using viable cells, by harnessing the regenerative capacity of nano-sized particles called extracellular vesicles that are naturally generated during bone formation. Excitingly, the team have shown in-vitro that if extracellular vesicles are applied in combination with a simple phosphate the therapy outperforms the current gold standard, BMP-2. "It is early days, but the potential is there for this to transform the way we approach tissue repair. We're now looking to produce these therapeutically valuable particles at scale and also examine their capacity to regenerate other tissues."