Tuesday, January 13, 2015

Stem Cells to Improve Failing Vision

In yet another amazing story in regenerative medicine, a woman in Japan received a retinal stem cell graft as therapy for age-related macular degeneration (AMD), as first reported in September, 2014.  She is the first of six patients who are to have this treatment, being performed at the RIKEN Center for Developmental Biology in Kobe, Japan.

AMD is a major cause of visual loss and blindness in adults over the age of 50.  The most common type is known as "dry" AMD (or central geographic atrophy), wherein vision loss occurs due to the loss of the photoreceptors known as rods and cones.  There is no recognized medical or surgical treatment for this condition, although certain vitamin and supplement regimens may help.  About 90% of cases are "dry" AMD.  (The other type is known as "wet" AMD where vision loss occurs due to the abnormal growth of  blood vessels.  There are multiple medications that can help with this condition, although some require direct injections into the eye on a routine basis.  The goal is to reduce the growth of these blood vessels and eliminate them.)

The woman mentioned earlier had skin cells harvested and then reprogrammed into specialized retinal pigment epithelial cells.  This is a type of induced pluipotent stem cell (iPS), wherein a patient's own cells are induced into a stem cell line that is wanted for a particular type of tissue therapy. These cells were then grafted into her eye as a patch with the hope of allowing these cells to maintain her own rods and cones.

Shinya Yamanaka and colleagues at Kyoto University first discovered iPS cells in 2006; Yamanaka was awarded the Nobel Prize for this work in 2012.

Mike Cheetham of the Institute of Ophthalmology at University College London (another site researching human embryonic stem cells and AMD) had this to say in regards to the Japanese trial - "If it goes well, it could be the start of a new era in personalized medicine."

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