On September 12, 2014, a team of eye specialists led by ophthalmologist Yasuo Kurimoto implanted a 1.3 by 3.0 millimeter sheet of retinal pigment epithelium cells into the eye of an elderly female patient at the Institute for Biomedical Research and Innovation in Kobe, Japan (1). This patient suffers from age-related macular degeneration (AMD), the most common cause of visual impairment in the elderly. AMD is characterized by gradual damage to the retinal pigment epithelium, a protective layer of cells adjacent to the photoreceptors of the retina (2).
Scientists hope pluripotent cells will usher in a new era of regenerative medicine
In order to potentially mitigate the effects of AMD, Dr. Masayo Takahashi reprogrammed cells from the patient’s skin to produce pluripotent stem cells (iPS cells), using a technique first described in 2006 by Dr. Shinya Yamanaka (3). Pluripotent stem cells are able to differentiate into any type of cell in the body, so Dr. Takahashi coaxed these cells to differentiate into retinal pigment epithelium cells for implantation (3).
Typically, an individual’s skin cells have the same set of DNA as the individual’s retinal cells, but mature skin cells have specific genes for skin cell development activated and genes that encode for other specialized tissue cells (such as retinal pigment epithelium cells) deactivated.
Dr. Yamanaka’s method converts mature cells back into stem cells, creating iPS cells (4). Unlike the stem cells that existed prior to 2006, iPS cells do not require a human egg for creation. Because human embryos had to be destroyed to gain those original types of stem cells, stem cell research has often been the source of both ethical and religious controversy. Instead, this new technique reprograms the subject’s own cells, which also reduces the risk of the body rejecting the implanted tissue. Dr. Takahashi’s studies indicate that iPS cells generated from the recipient’s own cells will not provoke an immune reaction in monkeys (3).
While promising, iPS cell treatments are still new. The elderly female patient was the first of six patients planned for this human pilot study in Japan (3). Cell biologists around the globe will be watching to see the treatment’s effectiveness and potential deleterious side effects, such as an immune response or cancerous growth (1). Scientists hope to use this technology in regenerative medicine to help numerous patients. Hopefully, this groundbreaking technique is the first step in a series of advances that will help millions worldwide.
Sources:
1. Cyranoski, D. (2014, September 12). Japanese Woman is First Recipient of Next Generation Stem Cells. Nature.com. Retrieved September 27, 2014, from http://www.nature.com/
2. (2014). World’s First Induced Pluripotent Stem Cells Clinical Study on Humans Launches in Japan. Stem Cells Translational Medicine, 3(9). Retrieved September 24, 2014, from http://stemcellstm.alphamedpress.org/site/misc/News159.xhtml
3. Cyranoski, D. (2014, September 10). Next-Generation Stem Cells Cleared for Human Trial. Nature.com. Retrieved September 24, 2014, from http://www.nature.com/
4. Abbott, A. (2012, October 8). Cell Rewind Wins Medicine Nobel. Nature.com. Retrieved September 27, 2014, from http://www.nature.com/
5. Cellular Reprogramming – A New Dimension in Stem Cell-Based Disease Modeling and Cell Replacement. (n.d.). LIFE & BRAIN GmbH. Retrieved September 24, 2014, from http://lifeandbrain.com/