In the research noted below, scientists have made initial inroads into the induced dedifferentiation of human cells. This is an attempt to recapture the behavior of tissues in highly regenerative species such as salamanders, and success here may be a step towards generating much greater regeneration of injuries and aged tissues suffering a lack of maintenance. Over the past decade considerable effort has gone into better understanding the precise mechanisms by which species such as salamanders and zebrafish can fully regenerate limbs and organ tissue. Part of the answer appears to be a different relationship between immune cells called macrophages and tissue regeneration, and the dynamics of cellular senescence may also play a role, but of primary interest is that the cells in these species respond to injury by dedifferentiating to form a blastema capable of regrowth. It remains to be seen whether this process can be safely recreated in humans:
A research team has adapted the astonishing capacity of animals such as newts to regenerate lost tissues and organs caused when they have a limb severed. Cells in newts can change in response to injury - a process known as dedifferentiation. The cells aggregate and return to a stem cell-like state to allow them to increase in numbers and generate the specialised cells needed for new tissue formation. But this form of tissue regeneration does not occur in humans, so the researchers recreated similar conditions in the laboratory by growing human cells as 3D aggregates.
The scientists cultivate the spheroid clusters of cells, which are just visible to the naked eye, in tiny cavities. The process involves reverting cells to an embryonic state. In doing so, the cells eat their own constituents and consequently reduce in size. "Using this technique, we have shown that human cells can also be dedifferentiated to an early embryonic stage. They are then capable of generating new tissues. We were able to use pharmaceuticals to induce cell self-eating effects and stimulate dedifferentiation though not as effectively as 3D culture, so we need to do more work on this. The next stage is to find out more about the dedifferentiation process so that we can find the right treatment to encourage tissue repair in the damaged joint. That is our aim."