They manage to restore a glimmer of life to the eyes of a dead man

They manage to restore a glimmer of life to the eyes of a dead man

Scientists temporarily restored a faint burst of life in dying cells of the human eye.

To better understand how nerve cells succumb to lack of oxygen, a team of American researchers measured the activity of mouse and human retinal cells shortly after death.

Surprisingly, with some adjustments to the fabric environment, they were able to live again cells’ ability to communicate hours later, reports ScienceAlert.

When stimulated by light, postmortem retinas have been shown to emit specific electrical signals, called B waves.


Scientists have momentarily restored a faint glow of life to human eye cells hours after death.

These waves are also observed in living retinas and indicate communication between all layers of macular cells that allow us to see.

It is the first time that the eyes of a deceased human donor react to light in this way, and some experts question the irreversible nature of death in the central nervous system, says ScienceAlert.

IS THERE LIFE AFTER DEATH?

“We were able to awaken photoreceptor cells in the human macula, which is the part of the retina responsible for our central vision and our ability to see fine detail and color,” says biomedical scientist Fatima Abbas from the University of Utah.

“In the eyes obtained up to five hours after death from an organ donor, these cells reacted to bright light, colored lights, and even very faint flashes of light.”

After death, it is possible to preserve certain organs of the human body for transplantation. But once circulation ceases, the central nervous system as a whole becomes unresponsive too quickly for any form of long-term recovery, he says. ScienceAlert.

However, not all types of neurons fail at the same rate. Different regions and different cell types have different survival mechanisms, which makes brain death all the more complicated.

This is the first time that the eyes of a deceased human donor have reacted to light in this way.

This is the first time that the eyes of a deceased human donor have reacted to light in this way.

Researchers have already had some luck. In 2018, scientists at Yale University made headlines by keeping pig brains alive up to 36 hours after death.

Four hours after death, they were even able to revive a small response, although nothing organized or global that could be measured with an electroencephalogram (EEG), he says. ScienceAlert.

The feats were achieved by halting the rapid decay of mammalian neurons, using artificial blood, heaters and pumps to restore the flow of oxygen and nutrients.

A similar technique now seems possible in mice and human eyes, which are the only extruded part of the nervous system.

By restoring oxygenation and certain nutrients to the eyes of organ donors, researchers from the University of Utah and Scripps Research were able to trigger synchronous activity between neurons after death, reports ScienceAlert.

“We were able to get the retinal cells to talk to each other, like they do in the living eye to mediate human vision,” says visual scientist Frans Vinberg from the University of Utah.

“Previous studies have restored very limited electrical activity in the eyes of organ donors, but this has never been achieved in the macula, and never to the extent that we have now shown.”

UP TO 5 HOURS AFTER DEATH

Initially, experiments showed that retinal cells continued to respond to light up to five hours after death. However, the crucial intercellular b-wave signals quickly faded, apparently due to the loss of oxygen, he says. ScienceAlert.

Even when retinal tissue is carefully protected from oxygen deprivation, researchers have not been able to fully restore robust b waves.

Retinal cells continued to respond to light for up to five hours after death.

Retinal cells continued to respond to light for up to five hours after death.

Moreover, the temporary reactivation of retinal cells does not mean that the donor eyeballs They can see, sure. Higher visual centers in the brain are needed to revive full visual sensation and perception.

However, some definitions of “brain death” require a synchronous loss of activity between neurons. If that definition is accepted, then the human retinas in the current study weren’t completely dead yet, he says. ScienceAlert.

If specialized neurons, known as photoreceptors, can be kickstarted to some degree, then this offers hope for future transplants that may help restore vision in people with eye disease.

That day, however, is still far away. Transplanted cells and donor retinal patches should somehow integrate seamlessly into existing retinal circuitry, which is a daunting challenge that scientists are already trying to overcome.

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