STEM CELLS SAVING SIGHT

Researchers Work Towards Ending Blinding Diseases

Two decades after University of Wisconsin-Madison biologist James Thomson’s unprecedented achievement in lab-grown human embryonic cells, pediatric ophthalmologist David Gamm, MD, PhD, is fighting blindness through generating ‘spare parts’ of human eyes, on the foundation of Thomson’s leading stem-cell work.

As a pediatric ophthalmologist, Professor Gamm understands how devastating it is to a family when the child is hopelessly losing their sight due to genetic eye disorders. Frustrated with the fact that the human eye is unable to reproduce photoreceptors, the critical light-sensing cells for one’s vision, and later inspired by Dr. Thomson’s discovery in stem-cell research, Dr. Gamm started an almost decade-long trial on realizing lab-grown photoreceptors.

Dr. David Gamm examines the eyes of Gavina Zimbric, of Waterloo, at UW Health’s University Station Clinic.

I learned about UW–Madison researcher James Thomson’s pioneering work in stem cells. We figured there must be a way to take these very undifferentiated stem cells, which are kind of little pieces of human-cell clay, and mold them into spare parts for the retina.

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Nearly ten years later, Dr. Gamm and his team have successfully developed methods to produce crucial human eye tissues in laboratories including photoreceptors and even whole human retinas, along with another project focusing on partial thickness cornea transplants, which are used to repair diseased tissue that clouds light entering the eye. Dr. Neal Barney, professor emeritus of ophthalmology, is developing a high-tech, synthetic carrier to deliver a thin, cadaver-derived corneal tissue during surgery. “These ultra-thin tissues can fold up like wet tissue paper during surgery,” Barney says. “The goal is to develop and manufacture a membrane to transport this tissue to the patient and hold it in place until it grafts, and then dissolve over time.” These discoveries bring hope for ending human vision loss.

Yet having practical sources of new human photoreceptors is only the first half of the mission. A much more challenging part of the battle awaits, for it is still uncertain whether the human eye can adapt regenerative cells. “If the downstream retinal circuit is a mess, putting fresh, new cells in there isn’t going to be of much help. In other words, a new light bulb is of no use if the socket wires are cut,” Gamm explains. “Fortunately, the socket wires appear to be in reasonable working order in many patients with photoreceptor degenerations.”

Many critical questions still need to be answered, and Dr. Gamm plans to start a clinical trial with UW Hospital in 2021. Gamm and his team are continuing to work towards the cure for eye-blinding disorders with stem-cell studies.

*Adapted from November 4, 2018 Wisconsin State Journal article: “UW researcher using stem cells to create ‘spare part’ for blindness” written by David Wahlberg.