Stem Cell Research Could Expand Clinical Use of Regenerative Human Cells

Research led by a biology professor in the School of Science at IUPUI has uncovered a method to produce retinal cells from regenerative human stem cells without the use of animal products, proteins or other foreign substances, which historically have limited the application of stem cells to treat disease and other human developmental disorders.

The study of human induced pluripotent stem cells (hiPSCs) has been pursued vigorously since they were first discovered in 2007 due to their ability to be manipulated into specific cell types. Scientists believe these cells hold considerable potential for cell replacement, disease modeling and pharmacological testing. However, clinical applications have been hindered by the fact that, to date, the cells have required animal products and proteins to grow and differentiate

A research team led by Jason S. Meyer, Ph.D., assistant professor of biology, successfully differentiated hiPSCs in a lab environment—completely through chemical methods—to form neural retinal cell types (including photoreceptors and retinal ganglion cells). Tests have shown the cells function and grow just as efficiently as those cells produced through traditional methods.

“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,” Meyer said. “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.”

In addition, 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, Meyer said. Furthermore, the cells function in a very similar fashion to human embryonic stem cells, but without controversial or immune rejection issues because they are derived from individual patients.

“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,” Meyer said. “We hope this will help us 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.”

“We’re talking about bringing stem cells a significant step closer to clinical use,” Meyer added.

The research will be published in the April edition of Stem Cells Translational Medicine.

Microchip Restores Vision

A wirelessly controlled microchip has restored limited vision to patients in a small experimental trial, report researchers in the Proceedings of the Royal Society B.

The German medical technology company Retina Implant developed the artificial retina, which was implanted in one eye of each participant as part of a company-funded trial. The patients had all been blinded by retinitis pigmentosa or another inherited disease that cause the eye’s light-detecting rod and cone cells, called photoreceptors, to degenerate and die over time. In theory, the device could also benefit patients with degenerative eye diseases such as macular degeneration, says Katarina Štigl, a clinical scientist and ophthalmologist at the University of Tübingen, who led the study.

With the implant, eight of the nine patients in the trial could perceive light. Five were able to detect moving patterns on a screen as well as everyday objects such as cutlery, doorknobs, and telephones. Three were able to read letters. Seeing their own hands and the faces of their loved ones had the biggest impression on the patients, says Štigl. “The very personal things, such as if a mouth is smiling, or the shape of a nose, are the most exciting for them,” she says.

The implanted device consists of a three-millimeter-square chip with 1,500 pixels. Each pixel contains a photodiode, which picks up incoming light, and an electrode and an amplification circuit, which boosts the weak electrical activity given off by the diode. A thin cable that runs through the eye socket connects the implant to a small coil implanted under the skin behind the ear, which means most of the system is invisible. The coil under the skin is powered by an external battery pack that can be held behind the ear with magnets.

The results follow an announcement earlier this week from California-based Second Sight that its Argus II system was approved for use in the United States. The two technologies take different approaches to restoring vision in patients with retinal degeneration. In Second Sight’s system, a camera mounted on eyeglasses picks up images that are converted into electrical signals by a small wearable computer. That data is then sent to a 60-electrode chip to stimulate neurons in the retina. The Retina Implant device instead attempts to directly replace the lost photoreceptors, allowing the remaining retinal circuitry to do the data processing.