Scientists at Forsyth may have moved one step closer to regenerating human spinal cord tissue by artificially inducing a frog tadpole to re-grow its tail at a stage in its development when it is normally impossible. Using a variety of methods including a kind of gene therapy, the scientists altered the electrical properties of cells thus inducing regeneration.
This discovery may provide clues about how bioelectricity can be used to help humans regenerate.
This study, for the first time, gave scientists a direct glimpse of the source of natural electric fields that are crucial for regeneration, as well as revealing how these are produced. In addition, the findings provide the first detailed mechanistic synthesis of bioelectrical, molecular-genetic, and cell-biological events underlying the regeneration of a complex vertebrate structure that includes skin, muscle, vasculature and critically spinal cord. Although the Xenopus (frog) tadpole sometimes has the ability to re-grow its tail, there are specific times during its development that regeneration does not take place (much as human children lose the ability to regenerate finger-tips after 7 years of age). During the Forsyth study, the activity of a yeast proton pump (which produces H+ ion flow and thus sets up regions of higher and lower pH) triggered the regeneration of the frog's tail during the normally quiescent time.
This research will be published in the April issue of Development and will appear online on February 28, 2007.
According to the publication's first author, Dany Adams, Ph.D., Assistant Research Investigator at the Forsyth Institute, applied electric fields have long been known to enhance regeneration in amphibia, and in fact have led to clinical trials in human patients. "However, the molecular sources of relevant currents and the mechanisms underlying their control have remained poorly understood," said Adams. "To truly make strides in regenerative medicine, we need to understand the innate components that underlie bioelectrical events during normal development and regeneration. Our ability to stop regeneration by blocking a particular H+ pump and to induce regeneration when it is normally absent, means we have found at least one critical component."