There are treatments that are pharmaceutical based and there are treatments that are based on cells and molecules already in the human body. Two research projects, one at Massachusetts Eye and Ear and one at the University of California, Irvine, are utilizing stem cells and antibodies, respectively, to treat eye diseases.
Stem Cells to the Rescue
Stem cells have been in the news on and off for the past 20 years. A group of researchers from Massachusetts Eye and Ear found that a stem cell treatment called cultivated autologous limbal epithelial cell transplantation (CALEC) was found to be safe and well-tolerated in four patients who had chemical burns in one eye.
How CALEC works is that stem cells are taken from the patient, in this case, the eye that didn’t experience the chemical burn, via a biopsy. It is then expanded and grown on graft. After two to three weeks, the graft is sent back to Massachusetts Eye and Ear and transplanted into the eye that has corneal damage.
When someone has an eye injury, like a chemical burn, he or she may experience loss of cells on the tissue surrounding the cornea. Without a healthy eye surface, the person can’t have an artificial cornea transplant, which is the current standard of vision rehab. The CALEC procedure makes it possible for normal tissue to grow back and the hope is that once the normal tissue grows back, further treatments can be done to restore vision.
In this study, five patients had chemical burns to one eye and four of them went through the CALEC procedure. The first patient, a 46-year-old male had a resolution of the eye surface which allowed him to undergo the artificial cornea transplant. The second, a 31-year-old, had a complete resolution of symptoms and had his vision improve from 20/40 to 20/30. The third patient, a 36-year-old male had his corneal defect resolved and his vision improved from being able to only see broad movements, like hand waving, to 20/30 vision. The fourth person, a 52-year-old, didn’t have a successful cell graft. Three years later, the cell graft was successful and his vision improved and then he received an artificial cornea.
Antibody as Treatment Target
Research at University of California, Irvine led to the discovery of an antibody that could become a treatment for Retinitis Pigmentosa. Scientists studied a specific molecule that they believe will lead to a treatment for a specific kind of Retinitis Pigmentosa, known as Rhodopsin-associated autosomal dominant RP (adRP). Rhodopsin is a light-sensing molecule in the retina that is located in the rod photoreceptor cells. Mutations in the Rhodopsin gene are the leading cause of adRP.
While Rhodopsin has been studied for over 100 years, its mechanism for converting light into signals have been difficult to study via experiments. So for this study, researchers utilized a special type of llama-derived antibody, called nanobody, that stops the process of Rhodopsin photoactivation. This allows the molecule to be studied at high resolution.
Scientists found that the nanobodies target a site that is unexpected on the Rhodopsin molecule. The site in question is near where the retinaldehyde binds. (Retinaldehyde is a form of vitamin A that combines with certain proteins to form visual pigments.) They also found that the stabilizing effect of the nanobodies can be applied to the Rhodopsin mutants that are related to retinal disease. The hope is to grow these nanobodies in the lab and utilize them as gene therapy for Retinitis Pigmentosa.
Strides made in stem cell therapy and antibody research mark significant milestones in the understanding and treatment of eye diseases. As these treatments evolve and undergo additional clinical studies, they offer hope for persons who experience eye injuries or Retinitis Pigmentosa. As vision research continues, the future of ophthalmic medicine holds the promise for improved vision for all.
https://openmd.com/define/retinaldehyde