Induced Stem Cells that Build Tissue
A group of researchers is claiming the creation of induced stem cells reprogrammed from adult somatic cells that, unlike the current standards for stem cell therapies, create daughter cells that participate in building tissue rather than affecting regeneration through signaling only. The claim is that this method recapitulates one of the primary mechanisms of limb regeneration seen in salamanders, in which which ordinary adult cells dedifferentiate to become multipotent stem cells capable of constructing multiple tissue types. The paper is to the point, but the publicity materials indicate that the authors think this is a very big deal. Given that they've not completed animal studies to prove the point, this may be premature, but we shall see.
Stem cell therapies capable of regenerating any human tissue damaged by injury, disease or ageing could be available within a few years. "This technique is a significant advance on many of the current unproven stem cell therapies, which have shown little or no objective evidence they contribute directly to new tissue formation. We are currently assessing whether adult human fat cells reprogrammed into induced multipotent stem cells (iMS) cells can safely repair damaged tissue in mice, with human trials expected to begin in late 2017. This technique is ground-breaking because iMS cells regenerate multiple tissue types. We have taken bone and fat cells, switched off their memory and converted them into stem cells so they can repair different cell types once they are put back inside the body."The technique involves extracting adult human fat cells and treating them with the compound 5-Azacytidine (AZA), along with platelet-derived growth factor-AB (PDGF-AB) for approximately two days. The cells are then treated with the growth factor alone for a further two-three weeks. AZA is known to induce cell plasticity, which is crucial for reprogramming cells. The AZA compound relaxes the hard-wiring of the cell, which is expanded by the growth factor, transforming the bone and fat cells into iMS cells. When the stem cells are inserted into the damaged tissue site, they multiply, promoting growth and healing. The new technique is similar to salamander limb regeneration, which is also dependent on the plasticity of differentiated cells, which can repair multiple tissue types, depending on which body part needs replacing.
Along with confirming that human adult fat cells reprogrammed into iMS stem cells can safely repair damaged tissue in mice, the researchers said further work is required to establish whether iMS cells remain dormant at the sites of transplantation and retain their capacity to proliferate on demand.