A Fortunate Discovery: Lacritin
By Nina Luning Prak, MD, PhD
Professor of Pathology and Laboratory Medicine at the Perelman School of Medicine of the University of Pennsylvania;
Chair, Autoimmune Association Medical and Scientific Advisory Council
Sometimes, the most groundbreaking discoveries in science happen when no one is expecting them. In 1992, at the University of Virginia, Dr. Gordon Laurie and colleagues were conducting a routine biochemical screen and came upon something extraordinary: a protein in tears with remarkable properties. This serendipitous moment of curiosity and chance would lead to a deeper understanding of eye health and pave the way for potentially life-changing treatments for dry eye disease.
Dry eye disease is a condition where the surface of the eye becomes irritated due to insufficient or poor-quality tears. This leads to symptoms such as burning or stinging sensation, redness, blurred vision, light sensitivity and watery eyes. Tears are far more than just water; they are a complex mixture of over 1,800 proteins and various lipids that work together to protect and nourish the eye. These proteins play a crucial role in maintaining the health of the eye’s surface, preventing infection, and ensuring clear vision. Understanding the specific functions of these proteins has become a focus of this groundbreaking research, as it provides insights into how the delicate balance of the tear film can be restored.
A protein produced in tears called lacritin has emerged as a key player in promoting and restoring the natural balance of the eye’s surface. Researchers found that people with dry eye disease, particularly those with autoimmune forms such as Sjögren’s syndrome, had significantly lower levels of active lacritin in their tears. This protein is now at the forefront of cutting-edge research, offering hope for millions suffering from a condition that is often misunderstood and underestimated in its negative impact on quality of life.
Researchers have determined that lacritin is like a multitool for your eyes. It helps restore natural tear production, ensuring a constant and nourishing tear layer that protects the eyes. When cells on the eye’s surface become stressed or damaged, lacritin triggers a repair process called autophagy, which clears away damaged proteins and restores energy to the cells. On top of that, lacritin helps repair damage to the cornea, the transparent front part of the eye, which is critical for maintaining clear vision.
These effects are highly targeted. Lacritin interacts with specific receptors on eye cells through a pathway called the lacritin-syndecan-1-heparanase axis, acting only where it is needed. This precision minimizes the risk of side effects making lacritin a promising candidate for future therapies. Synthetic forms of lacritin, such as a peptide called Lacripepâ„¢, are now being tested in clinical trials. These treatments aim to address the root cause of dry eye disease rather than just alleviating symptoms. Early results are promising, showing that lacritin may help restore natural tear production in severe dry eye cases, protect and repair damaged eye cells, and improve overall eye health and quality of life for patients.
The constant discomfort from dry eye disease can impact productivity, emotional well-being, and even simple daily tasks like reading or driving. The discovery of lacritin offers hope for a future where treatments go beyond masking symptoms to truly address the underlying problems.
In the meantime, if you’re dealing with dry eye, there are steps you can take to protect your eyes. Using artificial tears, staying hydrated, taking breaks from computer and phone screens, and managing environmental factors like dry air can help reduce symptoms. But with lacritin-based treatments on the horizon, relief may soon become much more effective and long-lasting.