For people completely blind because of a myriad of causes – genetic diseases, age -related conditions, accidents, battle injuries – the question often arises: I can’t just have a new eye? The parents of blind children sometimes ask: can I just give my child one of my eyes?
The transplantation of an eye seems so simple, but until recently, it was not considered an approach feasible to restore vision. The main experts in ophthalmology and medical quickly closed the conversation on the transplantation of the whole eyes, because it was, on several levels, far beyond the sciences and technologies available today to the surgical community. It was the business of science fiction films – not operating rooms.
However, in May 2023, the prospects for transplantation of whole eyes changed considerably when a military veteran involved in a high -voltage electric accident received a partial face and face transplant from a surgical team from Nyu Langone Health. Although the veterinarian did not find the sight in the transplanted eye, the eye has a good blood flow, normal pressure and its stems and stupid – the retinal cells that respond to light for vision – show sensitivity to light. Although the restoration of the vision is the ultimate objective, the results of this first eye transplantation were remarkable and revolutionary. The complete results were published on September 9, 2024, in the Journal of the American Medical Association (Jama).
Ecperatingly, the Advanced Research Projects Agency for Health (ARPA-H) launched the transplant program for allografts for human eyes in January 2024 in order to carry out an entire functional ocular transplantation, that is to say a restoration of vision. ARPA-H, a federal agency within the American Department of Health and Social Services, is responsible for conducting biomedical and health transformatives to provide health solutions to all.
More than a million Americans are irreparably blind with bilateral vision loss due to various conditions, including current diseases, age -related macular degeneration, glaucoma and diabetic retinopathy. The prevalence of irreversible blindness underlines the enormous need to develop procedures for the restoration of vision.
Do not be mistaken: the transplantation of the whole eyes (humid) is a very ambitious effort. Several revolutionary advances must be made so that Wet to Work.
According to the ARPA-H transplant of the opening of innovative solutions for human-eyed allografts, the program has three technical areas:
- Harvesting and preservation of fabrics (TA1)
- Return and repair of the optic nerve (TA2)
- Surgery, postoperative care and evaluation (TA3)
Harvesting and preservation of fabrics (TA1)
The supply of donor eyes for potential ocular transplantation is substantial. 70,000 Americans give their eyes for transplantation each year to their death. Eye donors are listed on the organ purchase and transplantation network (OPTN), a computer network connecting donors and recipients. Organ supply organizations, surgeons and organ transport and storage specialists work together to ensure the availability of viable eye tissue.
However, only part of the eye is currently used for transplantation. Cores are the most frequently transplanted eye fabric with 40,000 of these transplants carried out each year in the United States, the success of harvesting and the preservation of successful whole eyes requires new techniques to preserve the optic nerve, the retina and other eye tissue. Neuronal tissues require continuous oxygenation and are sensitive to the loss of nutrients.
The first TA1 objective is to develop technology and a protocol to preserve the viability of the eyes and the optic nerve outside the body for more than 24 hours in animal eyes (ex living). An analysis of the retinal structure will be carried out to guarantee that there is no sign of retinal detachment or corneal edema and that the retinal tissue remains healthy. The function of the retinas will be evaluated by electroreinograms (ERG) which measure retinal sensitivity.
The next TA1 objective is to extend the preservation of the eyes of human donors for more than 48 hours (ex living). The structure of the transplanted eyes will be evaluated using techniques such as optical coherence tomography (OCT), magnetic resonance imaging (MRI) and detecting degenerate retinal cells. ERGs will be performed to measure the retinal function.
Reworked and repair of the optic nerve (TA2)
The regeneration of the optic nerve to the restoration of the vision has been elusive and would in itself be a breakthrough for the communities of ophthalmology and neurology, including clinical researchers who work to restore the mobility of people with lesions of the spinal cord.
The initial objective of TA2 is to develop technologies to achieve repair / regeneration of the optic nerve in a small animal model. New technologies will include stem cells with nerve envelopes, bio-scafauds and / or neural survival factors. The visual function in animals will be measured by ERGs, acuity tests and / or a labyrinth.
The TA2 teams will then evaluate the repair / regeneration of the optic nerve and the whole eye transplantation in an important animal model in order to reach at least 50% of the regeneration and reconnection of the normal (basic) optic nerve. Retinal function and brain connection will be evaluated by tests such as visual potentials, which measure how the brain reacts to visual stimuli, optical motor responses and pupillary light reflexes.
In case of success, the TA2 teams will then work with the surgical teams for TA3 to assess the repair / regeneration of the optic nerve in recipients of all human ocular transplantation. Imaging technologies such as OCT and MRI can be used to assess the function of optical nerve connections. The vision of human recipients intends to be measured by tests of recognition of form, sensitivity to contrast and form recognition.
Surgery, postoperative care and evaluation (TA3)
Initially, the TA3 teams aim to develop microsurgery protocols to wet in a large animal and humans. In addition to implementing the regeneration / reconnection protocol of the optic nerve, surgeons will develop protocols for the attachment of the vascular system, musculature and peripheral nerves.
One or more protocols will be developed to minimize inflammation and post-operative rejection for at least six months. Surgeons will also try to minimize the disfigurement of the beneficiary. The ocular viability of donors will be evaluated using imaging technologies, in particular: Oct, MRI, CT and adaptive optics. A multibuminance mobility test, a labyrinth with variable light parameters, will be used to assess the visual function in large animals.
With success in large animals, surgeons will endeavor to succeed with objectives without immune rejection and sustained viability of the eyes for at least a year in humans. The visual function will be evaluated using a table of the Snellen eyes, including the possibility of seeing (with high magnification) large letters from a distance and the possibility of navigating without assistance. The recipients will also be invited to fulfill a vision and quality of life questionnaire.
Take advantage of the transplantation of the results of human -eyed alligreffe
Although the restoration of the vision is the main objective, the scope of the transplantation of the potential impact of the allogreffe program for human eyes transcends ophthalmology. The technologies and techniques developed for ocular transplantation and nervous regeneration can have a significant translation potential for other biomedical needs, in particular: lesions of the spinal cord, the regeneration of the central nervous system, the transplantation of retinal cells and tissues and other forms of transplantation of organs and tissues.
In summary, this Arpa-H program serves as a catalyst for innovation, leading to progress in several areas of medicine with the potential to transform the lives of countless individuals beyond those who have a loss of vision.
Organic author:
Chad Jackson, Ph.D.,, is the main director of the Pre -Creal Translational Research Program at the Fighting Blindness Foundation (the Foundation). Dr. Jackson will manage the reports and strategic planning of the ARPA-H human eyes allogrefts program on behalf of the Foundation, a Subwardee of the Program. Dr. Jackson has more than 20 years of experience in research and development in biomedical sciences and is a champion of international scientific commitment, the development of the innovation and entrepreneurship ecosystem as a means of solving the most difficult problems in the world. Before joining the Foundation, Dr. Jackson supported the Defense Advanced Research Projects Boilaries Office Agency covering subjects that extend on infectious diseases, synthetic biology and human performance. He is currently Chairman of the Board of Directors for Sowing Laboratories and is a member of Earlham College Board, member of the Board of Directors. Dr. Jackson received his doctorate. In Molecular & Systems Pharmacology from Emory University and a BA in Earlham College biochemistry.
“This research was funded, in part, by the Advanced Research Projects Agency for Health (ARPA-H). The points of view and the conclusions contained in this document are those of the authors and should not be interpreted as representing the official, expressed or implicit policies of the United States government. “
Photo: Jay_zynism, Getty Images
