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Disembodied human tear glands that cry sound like something out of a sci-fi movie. But in Holland, the functional tear glands that don’t stick to anyone’s eyes (or emotions) are starring in their own real-life drama.
Researchers at the Hubrecht Institute and UMC Utrecht used stem cells to develop small tear glands in a petri dish that mimics the real thing. They hope that these so-called organoids can serve as models to study how cells in human tear glands produce tears. The ultimate goal: to better understand and treat conditions such as dry eye disease or autoimmune Sjögren’s syndrome, as well as lacrimal gland cancer.
“Hopefully, in the future, this type of organoid can be transplanted to patients with non-functioning tear glands,” says Marie Bannier-Hélaouët, a doctoral candidate at the Hubrecht Institute for developmental biology and stem cell research. She co-authored a study published Tuesday in the journal Cell Stem Cell that details the project.
The organoids are built in vitro, in 3D suspension, from a small number of stem cells that eventually multiply to form something similar to a real organ, such as a mini-brain, bladder or, in this case, the glands located inside the eyelid. higher .
The lacrimal or lacrimal glands continuously supply fluid that passes through the surface of the eye every time we blink and then drain into small holes in the corners of the upper and lower eyelids before descending through the tear ducts to the nose. In addition to showing emotion, the fluid is essential for eye health, lubricating the cornea and helping to ward off bacteria. Lacrimal gland dysfunction can be irritating, causing an itchy, burning or burning sensation and sensitivity to light. But it can also be serious, leading to abrasions or ulcerations of the cornea or even blindness in the most severe cases.
The lacrimal glands are composed of several types of cells. The lab-grown glands in the Netherlands are made up of just one type, ductal, and cry in response to chemical stimuli like norepinephrine, a neurotransmitter that sends a message from our neurons to our tear glands.
The cells shed tears inside the organoid, causing it to swell.
Marie Bannier-Hélaouët Institute / Hubrecht
“Our eyes are always moist, just like the tear glands on a plate,” says Bannier-Hélaouët of the artificial glands. Bannier-Hélaouët works in the laboratory of molecular biologist Hans Clevers, who focuses on creating organoids for modeling diseases and has already recreated snake venom glands and lacrimal glands in mice.
You won’t go into Clevers’ lab and see big teardrop-shaped drops floating in pots. The cells shed tears inside the organoid, called the lumen. This causes the organoid to swell like a balloon, with the size indicating how much tear production and secretion is taking place.
This is not the first time that scientists have created components of the human eye from stem cells. In 2018, a team from John Hopkins University created parts of the eyeball in the hope of better understanding how and why we developed “trichromatic vision” – the ability to see in red, blue and green.
Dutch researchers recognize the limitations of their lacrimal gland, as it is composed of only one of the main types of cells found in the gland. They say they would eventually like to develop an entire tear gland from the wide range of cells that make it up, gaining an even more robust understanding of how we form tears.