Ocular diseases like age-related macular degeneration and Stargardt disease affect millions of people around the world, causing vision loss or blindness and often leading to blindness as traditional treatment methods have limited success. Stem cell therapy offers hope to those afflicted by such diseases.

However, not all stem cell treatments are equal; certain companies are taking advantage of patients’ understandable desire for sight-restoring treatments by offering subpar solutions.

Regenerative Medicine

Regenerative medicine is an expanding research field devoted to replacing and regenerating human tissues and organs using stem cells, tissue engineering techniques, biomaterials, cell biology knowledge and medical experience. Regenerative medicine promises to revolutionize medicine by helping scientists cure diseases and restore lost functions more easily than ever.

Stem cells form the building blocks for all tissues in our bodies. With their ability to differentiate into various cell types needed by your body and repair damaged tissues and organs, stem cells play an integral part of regenerative medicine treatments such as muscle repair and nerve regeneration therapies, while stimulating new healthy tissue formation while increasing blood flow to damaged areas.

Numerous studies have demonstrated the power of stem cell therapy to slow or even reverse retinal degeneration. One such study on patients with Stargardt disease demonstrated this fact by finding that 62% who received autologous bone marrow stem cells saw their vision stabilize or improve following treatment, while another research paper reported 48% reduced rate of vision loss among this population.

Researchers from UCLA were so encouraged by these studies, they have begun testing an embryonic stem cell-based retinal replacement therapy. Injecting stem cells directly into the eye allows them to travel towards and migrate towards retinal pigment epithelium (RPE), replacing any lost cells due to age-related macular degeneration or Stargardt macular dystrophy.

UCLA scientists have already reported eye improvements among two patients who received injections of human embryonic stem cell derived regenerative cells. Both showed improvement in the area of their central vision; one with Stargardt’s macular dystrophy saw her eyesight improve enough that she was able to read 33 letters on an eye chart – an impressive feat and the first time this treatment has ever been implemented for such conditions.

Before they can be widely utilized, however, these results must first be confirmed through further clinical trials and/or evidence-based practice. It is always advisable to consult a trained physician prior to engaging in any experimental therapy involving stem cells; their counseling becomes even more essential as stem cell therapies enter well-planned trials and potentially evidence-based practice.

Transplantation

Retinal degeneration diseases, including age-related macular degeneration and Stargardt disease, can result in permanent blindness. Traditional treatments have proven ineffective; thus prompting researchers to explore alternative approaches such as stem cell therapy for these conditions – providing hope to millions who are impacted by them.

Scientists have used laboratory-derived pluripotent stem cells to transplant them into damaged areas of the eye. These stem cells have shown to repair some damage to retina, improving vision for those suffering from Stargardt disease and macular degeneration. A more promising approach would involve using blood or skin cells from patients themselves as the source for pluripotent stem cell production – these could then be differentiated into retinal cells for transplant into their eyes.

UCLA scientists reported in a recent study that two patients with Stargardt disease reported improvement after receiving injections of human embryonic stem cells as treatment. This marks the first documented evidence of success of using embryonic stem cells as therapy.

The study involved allogeneic transplantation. With allogeneic transplantation, stem cells from healthy donors are extracted and then transplanted directly into patients to replace damaged blood-forming cells. Success for allogeneic transplantation lies in how closely donated HLA antigens match with those found within their own stem cells; when more matches exist between donated HLA antigens and donor stem cells the less likely is is for complications known as Graft-Versus-Host Disease (GVHD) to occur.

GVHD occurs when newly transplanted blood-forming stem cells from a donor identify cells within the recipient’s body as foreign and begin attacking them, either shortly after transplantation (acute GVHD) or much later during treatment (chronic GVHD). To decrease the likelihood of this happening, patients receive medications designed to suppress their immune systems prior and during transplantation procedures.

Research in this area represents an essential step towards developing cell-based treatments for degenerative eye conditions like macular degeneration and Stargardt disease. Scientists hope that one day soon they may use induced pluripotent stem cell technology to produce retinal cells for transplantation into the eye using transplantable retinal cell cultures generated through IPC technology.

Drugs

Hereditary retinal dystrophies such as Stargardt disease are one of the primary areas of research into human stem cells. This group of conditions affects retinal pigment epithelial cells (RPEs) which ultimately leads to macular degeneration and blindness, but until recently understanding their pathology was limited by limited sample availability from affected patients and genetic heterogeneity. With the discovery of induced pluripotent stem cells with unlimited self-renewal capacity that can differentiate into patient-specific RPE cells, researchers now study these diseases with unprecedented levels of detail; it also opens new avenues for drug discovery as well as cell replacement therapies.

Recent clinical trial involving stem cell implants into the eyes of a patient suffering from Stargardt disease has produced encouraging results. Europe’s first study using embryonic stem cell-derived retinal pigment epithelial cells for treating macular degeneration showed promise; stable cells allowed her to improve from 20/500 vision acuity to 20/320; this allowed her to read charts with 33 letters instead of just 20 letters after this procedure was performed.

Bone marrow-derived stem cells offer another promising treatment option for Retinitis Pigmentosa (RP). When transplanted directly into the eye, these can help replace RPE cells destroyed by RP. As they’re non-viral and avoid risks associated with viral vectors (AAV) used in other gene therapy studies, their use could potentially avoid an infection risk associated with such treatments.

Hopes exist for future therapies using retinal pigment epithelial cells derived from human embryonic stem cells to treat RP and hereditary macular dystrophies, although these remain in early development stages and show promise of slowing macular degeneration progression.

At present, several medications exist for treating Stargardt disease. The most frequently prescribed drugs include hydroxychloroquine, luteinamide and a form of vitamin E known as a-tocopherol – all often combined in order to increase chances of successful RPE stem cell transplantation and improve quality of life for those living with Stargardt disease.

Gene Therapy

Gene therapy allows researchers to target specific diseases by altering their genetic code to make it healthier, using viruses or inserting the gene directly into stem cells. Genes play an integral part in how our bodies operate and produce proteins; when diseases cause certain genes to turn on or off, our bodies cannot produce healthy proteins; similarly when damaged DNA affects cell functions.

Stargardt disease is caused by an abnormal gene, ABCA4, that leads to the accumulation of vitamin A dimers, lipofuscin and complement inhibition, all which are detrimental to retinal pigment epithelium health and may result in vision loss. Multiple medications have been developed to address this problem but none has passed clinical trials; some experimental and clinical studies of intravitreal vector injection of functional ABCA4 genes into retinal pigment epithelium have shown promising results.

Researchers at the University of California, Los Angeles are creating a system that uses each patient’s skin cells to generate induced pluripotent stem cells that will then transform into retinal cells for transplantation with minimal risk of rejection. They expect commercial release sometime around 2023.

Scientists from another team are developing a treatment using human embryonic stem cells to address Stargardt macular degeneration and yellow-spotted abiotrophy of the retina (YSA). Their goal is to use these new cells to replace those destroyed by disease; their first phase 1 trial will test this approach on twelve patients.

Nanoscope Therapeutics is a biotechnology company focused on creating gene-agnostic optogenetic therapies to restore sight for millions of people blinded by retinal degenerative diseases. Their lead asset MCO-010 is currently in multicenter Phase 2b trials for both Retinitis Pigmentosa and Stargardt disease in the U.S. with top line data expected sometime during Q1 2023.