Tears seem simple, but the tiny glands that produce them are among the least understood organs in the human body. By growing miniature human tear glands in the lab and coaxing them to “cry,” scientists have opened a new window on why eyes dry out, scar and sometimes go painfully blind. Their work is now revealing a hidden cellular cleanup system inside these glands that could explain why some people’s tears fail them when they need them most.
What began as a bold attempt to grow functioning human tear tissue outside the body has evolved into a powerful model for decoding dry eye disease and related disorders. I see this new generation of “crying” organoids as a turning point, not only for treating chronic irritation and pain, but also for understanding how a neglected organ quietly protects vision every waking moment.
Why scientists set out to grow human tear glands
The human lacrimal gland sits tucked under the upper eyelid, constantly bathing the eye in a thin film of fluid that keeps the cornea clear and infection at bay. When that system falters, people can develop severe dry eye, corneal damage and even blindness, yet for decades researchers had little access to healthy human tissue and almost no way to watch the gland at work in real time. That gap is what pushed teams in Europe and Asia to attempt something that once sounded like science fiction: growing human tear glands in three dimensions from stem cells and small tissue samples.
By creating these lab-grown structures, scientists hoped to move beyond animal models and flat cell cultures that never fully captured how a real lacrimal gland behaves. The new work on Scientists Grew Human Tear Glands frames the effort as a way to Solve a long-standing Painful Mystery about why some glands shut down while others keep producing tears for a lifetime, and it shows how organoids can finally bring that mystery into focus.
From flat cells to 3D organoids that actually cry
Earlier work on the eye relied heavily on sheets of cells grown on plastic, which are useful for basic biology but lack the complex architecture of a real gland. The breakthrough came when researchers learned to coax stem cells and small biopsies into spherical clusters that self-organize into ducts and secretory pockets, mimicking the lacrimal gland’s branching structure. These three-dimensional “organoids” respond to chemical signals, change shape and, crucially, can be triggered to release fluid in a way that resembles natural tear production.
In one widely cited experiment, scientists reported that they had Scientists Grew Tiny Tear Glands in a Dish and Then Made Them Cry by exposing the organoids to nerve-like signals that normally tell the gland to release tears. At first, it was not clear whether these droplets were truly comparable to human tears, but careful analysis of the proteins and salts in the secreted fluid showed that the miniature glands were recapitulating key features of natural tear production.
The hidden cleanup system inside tear glands
Once researchers had a reliable model of the lacrimal gland, they could start probing its inner workings in ways that would be impossible in a living person. One of the most striking findings came when teams focused on autophagy, the cell’s built-in recycling and cleanup system. In healthy tissue, autophagy helps clear damaged proteins and organelles, preventing toxic buildup that can derail normal function. In the tear gland, that process appears to be especially important, because secretory cells are constantly producing and packaging proteins for export.
Using genetic tools to switch off this cleanup machinery in stem cell-derived organoids, scientists saw the entire miniature gland change character. As one report put it, Interestingly, when autophagy was disabled, the cellular composition of the organoids shifted, with secretory cells dwindling and other cell types taking over. That finding suggests that a breakdown in this hidden cleanup system could be a root cause of some forms of dry eye, where the gland is still present but no longer able to produce a healthy tear film.
How Dutch researchers taught lab-grown glands to weep
The most vivid proof that these organoids behave like real glands came from a group in the Netherlands that set out to make them “cry” on command. Starting with small pieces of human lacrimal tissue, researchers from the lab of Hans Clevers grew spherical organoids that formed ducts and secretory pockets, then exposed them to the same chemical messengers that nerves use to trigger emotional tearing. Under the microscope, the organoids swelled as they filled with fluid, then released it into the surrounding medium, a miniature version of what happens in the eye.
Those experiments, described in detail by the Hubrecht Institute, showed that Scientists everywhere can use the model to study how tear production is regulated and to identify new treatment options for patients with tear gland disorders. The ability to watch a human-derived gland respond to stimuli in real time gives researchers a powerful way to test drugs that might boost or modulate tear output without risking damage to a patient’s only functioning gland.
What “crying” organoids reveal about dry eye disease
Dry eye is often treated as a minor annoyance, but for people with severe forms of the condition, every blink can feel like sandpaper scraping across the cornea. Traditional therapies, from artificial tears to anti-inflammatory drops, are largely trial and error, in part because clinicians have not been able to see what is going wrong inside the gland itself. With organoids, scientists can now recreate specific disease states by altering genes, blocking signaling pathways or, as with autophagy, disabling key housekeeping systems to see how the gland responds.
One line of work has focused on how tear-producing organoids respond to chronic stress and inflammation, conditions that mimic autoimmune diseases and long-term environmental irritation. In these models, the tiny glands become less responsive to stimulation and produce altered tear fluid, echoing what patients experience. The tear-producing organoids that researchers created, as described in a report on Mar, could one day help relieve medical conditions that cause dry eyes by serving as a testbed for therapies that restore normal secretion rather than simply masking symptoms.
Japan’s world-first tear duct organoid and Sjögren’s hopes
While European teams refined models of the main lacrimal gland, researchers in Japan turned their attention to the tear duct system that drains fluid away from the eye. A group at Osaka University reported a world-first tear duct organoid, grown from mouse and human cells, that recapitulates the structure of the lacrimal drainage pathway. Their aim was to understand how these ducts form and function, and how they might be repaired when disease or injury blocks the normal flow of tears.
The Osaka team believes that understanding the generation of lacrimal gland organoids could eventually help patients with autoimmune conditions that attack tear-producing tissue. In particular, they have highlighted the potential relevance for people with the chronic disease known as Sjögren’s syndrome, in which immune cells target moisture-producing glands throughout the body. According to their report on a tear duct organoid, the findings could inform strategies to regenerate or replace damaged lacrimal tissue in these patients, offering more than symptomatic relief.
Transplanting mini-glands and testing their function in animals
Growing organoids in a dish is one thing; proving that they can integrate into a living system is another. To test the functional capacity of their lab-grown glands, some teams have transplanted lacrimal organoids into rodents with damaged or underdeveloped tear systems. After transplantation, the organoids connected with surrounding tissue and began to secrete fluid, suggesting that they could, in principle, help restore tear production in a diseased eye.
These experiments, described in reports that note how researchers have developed a method to generate organoids that mimic the human lacrimal gland during development, show that transplanted lacrimal gland organoids can survive and function in vivo. One summary of this work explains that to explore the functional capacity of the organoids, the research team transplanted lacrimal gland organoids into rodent models and observed tear-like secretion, as detailed in a ScienceDaily report. While these are early-stage animal studies, they hint at a future in which patients with destroyed glands might receive living replacements rather than relying on drops and gels.
From basic biology to future replacement parts for the eye
Beyond disease modeling, organoids are already reshaping how scientists think about regenerative medicine for the eye. The Dutch group behind some of the earliest lacrimal organoids has suggested that, in time, these structures could be implanted into patients whose glands have been damaged by radiation, surgery or autoimmune attack. The Royal Netherlands Academy of Arts and Sciences, which supported this work, has emphasized that the lab-grown organoids will need further refinement before they can be used clinically, but the concept of replacing a failing gland with a bioengineered counterpart is no longer purely theoretical.
One account of this research notes that The Royal Netherlands Academy of Arts and Sciences sees these organoids as a step toward future treatments, even as it acknowledges that the current model of the tear gland is not perfect. The detached human tear glands that scientists have grown in a lab setting could give researchers a deeper understanding of how we cry and how dysfunction can lead to blindness, as highlighted in a separate report on Scientists Grow Functioning Human Tear Glands In a Lab.
What tear gland organoids teach us about other secretory organs
One of the underappreciated aspects of this work is how it feeds back into broader questions about gland biology. The lacrimal gland shares developmental pathways and structural features with salivary glands, pancreatic tissue and even some hormone-producing organs. By learning how to coax stem cells into forming tear-producing structures, scientists are refining recipes that could be adapted to grow other secretory tissues, each with its own role in health and disease.
To study tear production, developmental biologists have compared the lacrimal gland to a range of other organs, including salivary glands, certain cancers and even snake venom glands, which share branching architectures and secretory mechanisms. One detailed account of this comparative work appears in a follow-up discussion of how To study tear production, researchers have drawn parallels between these seemingly disparate tissues. That cross-pollination of ideas is already informing efforts to grow salivary gland organoids for patients who lose saliva production after head and neck cancer treatment.
The road ahead: from lab curiosity to clinical tool
For now, lab-grown tear glands remain a research tool, not a standard therapy. The organoids are small, fragile and still lack some of the supporting cells and blood vessels that a full-size gland would need to thrive in the body. Yet the pace of progress has been striking. In just a few years, scientists have gone from flat cultures to three-dimensional structures that can be triggered to cry, transplanted into animals and used to dissect the role of autophagy and other pathways in dry eye disease.
As the field matures, I expect to see these models used to screen drugs that could boost tear production, protect secretory cells from autoimmune attack or fine-tune the composition of the tear film itself. Reports on how Scientists grow tear gland organoids that can actually cry suggest that They could lead to new dry eye disease treatments or even personalized medicine, where a patient’s own cells are used to grow a mini-gland for testing. The journey from a Petri dish to the clinic will not be quick, but for millions of people whose eyes burn and blur every day, the prospect of therapies rooted in a deeper understanding of how we cry is nothing to brush aside.
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