Researchers from the laboratory of Jason S. Meyer have designed a protocol to generate pigmented retinal cells from induced pluripotent stem cells (iPSCs). Induced pluripotent stem cells are made from adult cells by means of genetic engineering techniques that introduce four specific transcription factors into the cells that turn on a variety of genes that dedifferentiate the adult into an embryonic stem cell-like cell. This embryonic stem cell-like cell is an iPSC. Because iPSCs are similar to embryonic stem cells, they can differentiate into any adult cell type.
Last year, a clinical trial that used embryonic stem cells to produce pigmented retinal was published. This trial injected retinal pigmented epithelial cells derived from embryonic stem cells into the retinas of two patients. Both patients suffered from retinal diseases that affected the pigmented retina. Both patients showed eyesight improvements in the injected eye, but one patient showed improvements in both eyes. Therefore, the results of this experiment are largely inconclusively. Also, the derivation of human embryonic stem cells requires the destruction of human embryos, which ends the life of a young human person. Therefore, iPSCs offer a potentially better ethical alternative to embryonic stem cells.
In Meyer’s laboratory, Meyer and his co-workers have discovered have invented a way to differentiate iPSCs from patients into retinal pigmented epithelia (RPE), and photoreceptors (the light-sensitive cells in the retina). When tested in culture, the iPSC-derived RPE cells grew and functioned just as efficiently as RPEs made from more traditional methods.
According to Meyer, assistant professor of biology in the Indiana University School of Medicine Stark Neurosciences Research Institute, “Not only were we able to develop these (hiPSC) cells into retinal cells, but we were able to do so in a system devoid of any animal cells and proteins. Since these kinds of stem cells can be generated from a patient’s own cells, there will be nothing the body will recognize as foreign.”
Meyer also noted that this research should allow scientists to better reproduce these cells because they know exactly what components were included to spur growth and minimize or eliminate any variations. Also, the cells derived from iPSCs function in a very similar fashion to cells derived from human embryonic stem cells, but they are not surrounded by the controversy that accompanies embryonic stem cells or the danger of immune rejection issues because they are derived from individual patients.
Meyer added: “This method could have a considerable impact on the treatment of retinal diseases such as age-related macular degeneration and forms of blindness with hereditary factors. We hope this will help to understand what goes wrong when diseases arise and that we can use this method as platform for the development of new treatments or drug therapies.”
Meyer continued: “We’re talking about bringing cells a significant step closer to clinical use.”