Stem cell eye drops show promise for treating dry eye in Sjögren’s
Treatment also eased symptoms of adults without disease in small trial
Using stem cell eye drops — ones containing mesenchymal stem cells, or MSCs, which can give rise to other cell types — was shown to ease the signs and symptoms of refractory, or hard-to-treat, dry eye disease in adults with and without Sjögren’s disease, according to new data from a small clinical trial.
Dry eye disease, which occurs when tears are unable to adequately lubricate the eyes, is a common symptom of not only Sjögren’s but a number of other conditions, the researchers noted. Here, the use of eye drops with MSCs was tested in a study in China involving patients with and without Sjögren’s whose symptoms did not respond to other treatments.
The results are promising, per the team.
“We have demonstrated that MSC eye drops might offer clinical efficacy and manageable safety in treating refractory [dry eye disease] for the first time, potentially bringing a new perspective on the treatment of such patients,” the researchers wrote.
The trial findings were detailed in “A first-in-human, prospective pilot trial of umbilical cord-derived mesenchymal stem cell eye drops therapy for patients with refractory non-Sjögren’s and Sjögren’s syndrome dry eye disease,” a study published in the journal Stem Cell Research & Therapy.
Testing eye drops containing mesenchymal stem cells, or MSCs
Symptoms of dry eye disease can include eye irritation and dryness, blurred vision, and the sensation of a foreign body in the eyes. Sjögren’s, a chronic autoimmune disorder that primarily affects the glands that produce tears and saliva, is a common cause of dry eye disease.
Treatments such as artificial tears, topical corticosteroids, and nonsteroidal anti-inflammatory therapies are available. However, the researchers noted, their efficacy “varies significantly among individuals,” and can “[cause] sight-threatening side effects,” with the outcomes for patients “often falling short of satisfactory.”
Now, a team from the Affiliated Hospital of Medical School at Nanjing University sought to evaluate the safety and efficacy of MSC eye drops in adults with dry eye disease who did not respond to current treatments; these patients were considered to have refractory dry eye disease.
A type of stem cells, MSCs can grow and give rise to other cell types in the body, such as those making up muscles, bones, cartilage, and fat. These cells can be isolated from several tissues, as well, including fat, bone marrow, and the umbilical cord. MSCs also can influence the activity of other cells, most notably immune cells, by releasing certain signaling molecules.
The research team conducted an open-label clinical trial (NCT05784519, ChiCTR2200058115) testing the stem cell eye drops in these patients, with follow-up at four weeks, or at about one month, and at one year.
“This clinical trial represents a groundbreaking exploration into the preliminary therapeutic potential and safety of umbilical cord MSC eye drops for patients with refractory [dry eye disease],” the team wrote.
Five study participants had been diagnosed with Sjögren’s, and 11 had dry eye disease but didn’t have Sjögren’s. All received eye drops with MSCs isolated from the umbilical cord, given twice daily for two weeks.
This clinical trial represents a groundbreaking exploration into the preliminary therapeutic potential and safety of umbilical cord MSC eye drops for patients with refractory [or hard-to-treat dry eye disease].
The researchers used OSDI, or ocular surface disease index, scores as a patient-reported measure of eye discomfort. Tcorneal fluorescein staining (CFS) scores were used for evaluating eye surface damage. Additional assessments for tear quality and quantity included the Schirmer I test (SIT), tear meniscus height (TMH), and noninvasive break-up time (NIBUT), which measures the stability of the tear film on the eye’s surface.
The results showed that the MSC eye drops significantly eased most signs and symptoms of dry eye disease in patients with and without Sjögren’s at four weeks, per the researchers. Benefits were particularly seen in terms of tear production, as measured by SIT and TMH, and reduced eye surface damage, as measured by CFS. Average NIBUT scores and self-reported OSDI scores also improved, but reached statistical significance only in patients without Sjögren’s.
Significant improvements across all measures were also seen one year after treatment in the group of patients who did not have Sjögren’s.
Analyses suggest drops work by reducing inflammation
The researchers also assessed the function of the meibomian glands, which produce a fat-like substance that overlays the eye surface to prevent tear film evaporation.
At four weeks, the MSC eye drops had significantly enhanced the protective fatty layer and reduced meibomian gland obstruction in both patient groups, the data showed.
In an analysis of tears before and after treatment, the stem cell eye drops significantly reduced the levels of two pro-inflammatory immune signaling proteins, interleukin-6 (IL-6) and IL-17A, in all patients.
Compared with patients without Sjögren’s, those with the disease had significantly lower levels of MUC5AC before treatment. MUC5AC is a protein found in human tear film that helps maintain eye surface lubrication. After treatment, the levels of MUC5AC rose significantly in Sjögren’s patients, per the data.
Further analyses suggested that MSC eye drops worked by reducing inflammation caused by a type of immune cell called Th17 cells.
While some patients experienced treatment-related adverse reactions, most were mild in severity and had a minimal impact on daily life. The most frequently reported adverse events were eye surface discomfort, such as foreign body sensation and stinging eye pain, all of which resolved within two days.
“Our study validated that the treatment of refractory [non-Sjögren’s dry eye] and [Sjögren’s dry eye] patients with MSC eye drops is a feasible and safe application method, particularly showing good and enduring efficacy for tear deficiency and meibomian gland blockage,” the researchers wrote.
The team noted the small trial size as a key limitation of their work.
“To further validate the therapeutic efficacy and explore the underlying mechanisms of treatment, it is necessary to conduct randomized controlled clinical trials with a larger sample size and an extended follow-up period,” the researchers concluded.
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