The BBC reports on another way to potentially guide cells in your body to take that extra step to repair damage: "cells in the heart's outer layer can migrate deeper into a failing organ to carry out essential repairs. The migration of progenitor cells is controlled by a protein called thymosin beta 4, already known to help reduce muscle cell loss after a heart attack. ... Progenitor cells are similar to stem cells, in that they have the potential to turn into different types of adult tissue. However, it had been thought there was no ready source of these cells in the heart, and to carry out repairs they had to be summoned up from the bone marrow. The latest research is the first to show that they actually reside within the heart tissue itself. ... when treated with thymosin beta 4, these adult cells have as much potential as embryonic cells to create healthy heart tissue ... In the future if we can figure out how to direct the progenitor cells using thymosin beta 4, there could be potential for therapy based on the patients' own heart cells."

Link: http://news.bbc.co.uk/2/hi/health/6143286.stm