Stop your sobbing – because scientists can do it for you. Using stem cells, Dutch researchers have grown small glands of human tears that are capable of “crying”.
Initially, when scientists were looking to develop this technology, their first point of call was to line the inside of the slit, as it replaces it every five days. They would take a tiny piece of condensate full of gas cells and feed it called growth factors to stimulate cell growth, in anticipation of the rapid growth of the stem cells.
“But to our surprise, the stem cells created a micro-organ… it is small, but every cell is different in the digestion you need to digest food,” said study author Hans Clevers, group director at the Hubrecht Institute for developmental biology and stem cell study and at the Princess Máxima Center for Pediatric Oncology.
That was back in 2009. Since then, researchers have created small versions – called organoids – of the liver, pancreas, bladder and more. They even moved from mammals to reptiles, successfully growing snake venom glands. Last year, Clevers PhD students chose to work on human tear glands.
After first creating tear glands for mice, they moved on to human material. Suspended in gel, the tiny piece of donated human material was given a cocktail of growth factors. After about a week, the researchers broke it up into small pieces and fed it more to create several microbes. “They looked like little balloons,” Clevers said.
Tears are useful to their human guest in a number of ways. They release a thin layer of fluid that irritates the cornea, thickens the surface of the eye, protects it from irritants and infections, and provides nutrition. The glands are also responsible for producing tears, whether due to physical exertion, such as the sticking of a nail in your eye, or emotional distress, caused by, for example, a car overturning. on your pet cat. In each case, the brain commands the tear glands to cry.
“Adrenaline is the chemical message that comes from the neurons… to your tea glands. So, to really show that we had tear glands in action, we had to show that they would respond to adrenaline, ”Clevers said.
When the microorganisms received a continuous supply of cock the growth factor, they did not shed many tears when they encountered adrenaline. But once they were cut out of the juice, the cells stopped dividing and had a chance to settle down and mature – the adrenaline quickly brought to tears, he explained.
The small glands quickly resembled a balloon because there were no ducts for the fluid to escape. Eventually, they were made to rip or rip themselves, dribble out some liquid in the form of droplets, Clevers added.
The model has some limitations. The researchers captured one cell – the ductal cell – that contains the tear gland, but the glands are also made up of other cells. Moreover, these organs are not part of the human body – in which muscle glands can be wrapped around muscles and blood vessels – and so their activity is restricted, he warned.
“It’s a reduction model. But the essence of the tear gland is captured: that is, the formation of the tears and then the result of a tear drop stimulated by adrenaline. “
This model can now be used by researchers around the world to identify new drugs for patients who do not shed enough tears and to study the potential for tear gland cancers. be treated. Finally, this type of organoid could be transmitted to patients with inoperable tear glands, the authors suggested in the journal Stem Cell.
Meanwhile, researchers at Clevers ’lab are already monitoring their next project: crocodile tears.
“We want to grow crocodile tear glands,” Clevers said. “Crocodiles don’t cry because they are sad or something; they are just trying to get rid of salt. That’s why it’s scientifically interesting to study how this works, how they use the tear glands as kidneys. ”