The axolotl model for regeneration and aging research: a mini-review.

Although regeneration of tissues occurs in all adult tetrapods, the ability to regenerate complex structures such as limbs is limited to urodeles (newts and salamanders). Given that many of the biological processes and the signaling pathways that control these processes are highly conserved among all tetrapods, it is likely that humans have the potential to regenerate structures in the same way as salamanders. Thus the remarkable regenerative abilities of salamanders demonstrate what we reasonably can expect in terms of enhancing our regenerative potential. Although most of what is understood about regenerative mechanisms pertains to the repair of acute injuries, we assume that these same mechanisms could be utilized therapeutically to slow or even reverse chronic damage associated with aging. The axolotl model provides the opportunity to understand the behavior of cells to give the desired outcome of controlled growth and pattern formation leading to regeneration rather than aging and cancer. In this paper we present an overview of several important aspects of regeneration biology with an emphasis on the Mexican axolotl (Ambystoma mexicanum) as a model organism for identifying relevant signaling pathways and factors regulating limb regeneration. We also speculate about how these mechanisms could be utilized to reverse the aging process. By understanding the mechanisms of regeneration, we eventually will be able to enhance our intrinsic regenerative abilities in order to slow and even reverse the damage of aging.