RP Treatment Derived from Induced Pluripotent Stem Cells Advances into Clinical Trial
The stem cells were derived from mature blood cells and coaxed to become photoreceptors
Clinical researchers from Kobe City Eye Hospital in Japan have performed the world’s first transplant of photoreceptors derived from induced pluripotent stem cells (iPSC) into the eye of a person with retinitis pigmentosa (RP). The primary goal of the clinical trial is to assess safety of the potential therapy.
The iPSC used in the RP study were derived from the mature blood cells of a person without a retinal disease. The researchers genetically tweaked the blood cells to revert back to a stem cell state and then coaxed them forward to become three-dimensional retinal tissue, which is comprised of a mixture of different retinal cell types. The researchers then developed a sheet of photoreceptor cells from the mixture.
Stem cells, which can be obtained from a variety of sources, are attractive for use in therapies, because they can be developed into almost any cell type in the body, including photoreceptors.
Photoreceptors are the light-sensing cells in the retina that make vision possible. Loss of photoreceptors is the hallmark of RP and other inherited retinal diseases.
“We are pleased to see another induced pluripotent stem cell-based therapy advancing into the clinic to assess its potential to treat inherited retinal diseases,” says Brian Mansfield, PhD, executive vice president for research and interim chief scientific officer at the Foundation Fighting Blindness. “The retina consists of a complex layering of different cells, precisely oriented to each other, which creates many challenges in replacing a single cell type like the photoreceptor. We need to keep in mind that this is still very early stage research and evaluating safety is the primary goal. But it is an important step forward in our search to find treatments and cures for inherited retinal diseases.”
The iPSC used in the trial were developed by Shinya Yamanaka, MD, PhD. His recent work with photoreceptors extends on previous work from 2014 when he and his colleagues transplanted retinal pigment epithelial (RPE) cells derived from iPSC into a patient with wet age-related macular degeneration (AMD). RPE cells provide important supportive functions for photoreceptors and are affected first in people with AMD. Degeneration of RPE leads to loss of photoreceptors.
David Gamm, MD, PhD, a researcher at the University of Wisconsin-Madison, is developing iPSC-derived retinal therapies, including a three-dimensional patch comprised of both photoreceptors and RPE to potentially restore vision to people with advanced retinal conditions. The Foundation has funded Dr. Gamm for his iPSC research.