|Dr. Sheldon Miller (l), Dr. Kapil Bharti (c) and Dr. Mahendra Rao are positioning NIH as a leader in the development of stem cell therapeutics for eye diseases.
The National Eye Institute and the NIH Center for Regenerative Medicine convened an international group of scientists and clinicians recently to chart a path to clinical trials for stem cell therapies for degenerative eye diseases. “Working Together Towards a Cell-Based Investigational New Drug” was the third in a series of stem cell meetings that NEI began in 2009.
Stem cells have the potential to differentiate into a variety of mature cell types and can be obtained from both fetal and adult tissues. Recently, intense interest has centered on induced pluripotent stem (iPS) cells, which are made by reprogramming mature cells, such as skin or blood cells, into a developmentally immature state. They can then be coaxed to mature into other cell types. The use of iPS cells provides a theoretically unlimited supply of human cells to study disease and test new therapies. A major goal of stem cell research is to generate transplantable cells and tissues for disease treatment.
“We are at an inflection point historically in terms of opportunities to apply truly novel approaches to diseases that have previously vexed us,” said NIH director Dr. Francis Collins. “And particularly so to eye diseases because of the many characteristics that make the eye so appealing.” The eye is considered well-suited to stem cell therapy because it is easily accessible, less prone to immune rejection of transplanted cells and tissues and its function is easy to test.
Leaders from several research groups with plans for clinical trials of stem cell-based therapies for retinal diseases attended the meeting. Among them were Dr. Masayo Takahashi, RIKEN Center for Developmental Biology, Japan; Dr. Peter Coffey, University College London; Dr. Mark Humayun, University of Southern California; Dr. Dennis Clegg, University of California, Santa Barbara; Drs. Sally Temple and Jeffrey Stern, New York Neural Stem Cell Institute; and Dr. Eyal Banin, Hadassah-Hebrew University Medical Center, Israel. The meeting featured roundtable discussions about regulatory requirements to initiate clinical trials, ethical considerations and licensing and manufacturing of stem cell-related technology.
Dr. Sheldon Miller, director of NEI’s intramural research program, and Stadtman investigator Dr. Kapil Bharti, also of NEI, have developed protocols for the generation of retinal pigment epithelium (RPE) from iPS cells. The RPE is a single layer of cells in the back of the eye that provides metabolic support to the photoreceptors, which are light-stimulated nerve cells that transmit visual information to the brain. The RPE has been implicated in several eye diseases such as age-related macular degeneration, the most frequent cause of vision loss in Americans over age 65. Miller and Bharti grow the RPE cells on a fabric-like matrix called a scaffold, which enables them to produce RPE tissue in flat sheets for transplantation into the back of the eye. And they have developed physiological assays to authenticate these RPE tissues before and after transplantation into animal models.
Meeting organizers Miller, Bharti and NIH CRM director Dr. Mahendra Rao are positioning NIH as a leader in the development of stem cell therapeutics for eye diseases. In collaboration with the Clinical Center cell processing section, headed by Dr. David Stroncek, and private-sector firms, they hope to help build an “alpha” clinic at NIH with the capacity to manufacture clinical-grade iPS cells, conduct preclinical work and perform stem cell trials. The alpha stem cell clinic concept was conceived by Dr. Ellen Feigal and colleagues at the California Institute for Regenerative Medicine.
“Such a clinic would be able to recruit the right patients, create clinical-grade iPS cell banks and tissues, conduct animal testing, develop a drug master file and assist with preparing submissions to the FDA for investigatory new drug applications,” said Bharti. By providing necessary infrastructure, he said, such a clinic would help accelerate stem cell therapies.