Scientists have managed to “revive” light-sensitive cells in the eyes of organ donors: they have restored their ability to interact post-mortem. The researchers were able to recover a unique electrical signal, known as a “b wave,” that is only seen in the eyes of living people.
A team of researchers from the University of Utah and the Scripps Research Institute, in the United States, managed to recover the functionality of the cells responsible for processing light stimuli in the human eye after death: they were able to “revive” them and make them interact in donor eyes, including a electrical “signature” distinctive called “wave b”, which is only detected in life.
The discovery, which could transform research on the human brain and vision, is developed in a new study recently published in the journal Nature. According to a press release, specialists led by Fatima Abbas used the retina as a model of the central nervous system to investigate how neurons linked to vision die and develop new methods to “revive” them and recover its essential functions, after the death of a person.
Restore communication between cells
Billions of neurons in the central nervous system are known to transmit sensory information in the form of electrical signals: in the eyes, a type of specialized neurons known as photoreceptors are responsible for detecting and processing light. The scientists were able “wake up” photoreceptor cells in the human macula, which is the part of the retina responsible for our central vision and our ability to see fine details and distinguish colors.
In the study, the researchers measured responses elicited by light in macular photoreceptors human in eyes removed from donors, up to 5 hours after death. Thus, they identified the factors that drive the loss of light signaling after the cessation of biological function and, at the same time, designed a method to recover them.
Although other experiments had previously managed to “revive” the photoreceptors, the cells seemed to have lost their ability to communicate with each other on the retina. The team of specialists identified that oxygen deprivation was the critical factor leading to this loss of communication.
The “electrical signature” of living eyes
In this way, they created a series of conditions and developed devices that made it possible to restore oxygenation and other nutrients in the eyes of donors. By stimulating the retina and measuring the electrical activity of its cells, they found that they had succeeded in restoring a specific electrical signal that is seen in living eyes: the “b wave”. This is the first record of b waves made from the central retina of post-mortem human eyes.
The process demonstrated by the team of specialists could be used to study other neuronal tissues in the central nervous system, with the aim of obtaining their recovery after death. Furthermore, it is a transformative technical breakthrough that can help develop a better understanding of the neurodegenerative diseasesmainly those that affect the retina and cause blindness, such as macular degeneration.
Revival of light signaling in the postmortem mouse and human retina. Abbas F, Becker S, Jones BW et al. Nature (2022). DOI:https://doi.org/10.1038/s41586-022-04709-x