From ScienceDaily: "researchers were able to program bone marrow stem cells to repair damaged retinas in mice [which] implies that blood stem cells taken from bone marrow can be programmed to restore a variety of cells and tissues, including ones involved in cardiovascular disorders such as atherosclerosis and coronary artery disease. ... To our knowledge, this is the first report using targeted gene manipulation to specifically program an adult stem cell to become a new cell type. Although we used genes, we also suggest you can do the same thing with drugs - but ultimately you would not give the drugs to the patient, you would give the drugs to their cells. Take the cells out, activate certain chemical pathways, and put the cells back into the patient. ... scientists describe how they used a virus carrying a gene that gently pushed cultured adult stem cells from mice toward a fate as retinal cells. Only after the stem cells were reintroduced into the mice did they completely transform into the desired type of vision cells, apparently taking environmental cues from the damaged retinas."