Pathophysiology of Corneal Endothelial Cell Loss in Dry Eye Disease and Other Inflammatory Ocular Disorders

Cell therapy in the cornea: The emerging role of microenvironment

The cornea is an ideal testing field for cell therapies. Its highly ordered structure, where specific cell populations are sequestered in different layers, together with its accessibility, has allowed the development of the first stem cell-based therapy approved by the European Medicine Agency. Today, different techniques have been proposed for autologous and allogeneic limbal and non-limbal cell transplantation. Cell replacement has also been attempted in cases of endothelial cell decompensation as it occurs in Fuchs dystrophy: injection of cultivated allogeneic endothelial cells is now in advanced phases of clinical development. Recently, stromal substitutes have been developed with excellent integration capability and transparency. Finally, cell-derived products, such as exosomes obtained from different sources, have been investigated for the treatment of severe corneal diseases with encouraging results. Optimization of the success rate of cell therapies obviously requires high-quality cultured cells/products, but the role of the surrounding microenvironment is equally important to allow engraftment of transplanted cells, to preserve their functions and, ultimately, lead to restoration of tissue integrity and transparency of the cornea.

Role of topical and systemic immunosuppression in aqueous-deficient dry eye disease

Immunosuppression in aqueous-deficient dry eye disease (ADDE) is required not only to improve the symptoms and signs but also to prevent further progression of the disease and its sight-threatening sequelae. This immunomodulation can be achieved through topical and/or systemic medications, and the choice of one drug over the other is determined by the underlying systemic disease. These immunosuppressive agents require a minimum of 6-8 weeks to achieve their beneficial effect, and during this time, the patient is usually placed on topical corticosteroids. Antimetabolites such as methotrexate, azathioprine, and mycophenolate mofetil, along with calcineurin inhibitors, are commonly used as first-line medications. The latter have a pivotal role in immunomodulation since T cells contribute significantly to the pathogenesis of ocular surface inflammation in dry eye disease. Alkylating agents are largely limited to controlling acute exacerbations with pulse doses of cyclophosphamide. Biologic agents, such as rituximab, are particularly useful in patients with refractory disease. Each group of drugs has its own side-effect profiles and requires a stringent monitoring schedule that must be followed to prevent systemic morbidity. A customized combination of topical and systemic medications is usually required to achieve adequate control, and this review aims to help the clinician choose the most appropriate modality and monitoring regimen for a given case of ADDE.

Moxibustion with Walnut Shell Spectacles Could Improve the Objective Symptoms and Tear Film Stability of Patients with Dry Eye Disease: A Randomized Controlled Trial

Objectives

This study aims to evaluate the efficacy and acceptability of moxibustion with walnut shell spectacles in treating dry eye disease (DED) patients and to provide treatment options.

Methods

126 DED patients were randomly allocated into the moxibustion group (treated by moxibustion with walnut shell spectacles, 64 cases) and the artificial tears group (treated with sodium hyaluronate eye drops, 62 cases). Evaluate the changes in the ocular surface disease index (OSDI), the visual analogue scale (VAS) of ocular discomfort, the tear film break-up time (TBUT), corneal fluorescein staining (CFS), and the Schirmer I test during the trial at baseline and after 1-week, 2-week, 3-week, and 4-week treatment. Evaluate the OSDI scale and the ocular symptom VAS scale one month after the end of treatment.

Results

There were no significant differences in baseline characteristics between the two groups. For OSDI scores, the results showed that the efficacy of the moxibustion group was no less than that of the artificial tear group. For VAS of ocular discomfort, both groups significantly reduced their score compared with baseline, and for the moxibustion group, the decrease was more significant. For TBUT, FAS, and PPS, results showed that the efficacy of the moxibustion group was significant in both eyes after 4 weeks of treatment, but the right eye was in the artificial tear group. For CFS and Schirmer I test scores, there was no significant effect for both groups.

Conclusion

Moxibustion with walnut shell spectacles could improve the clinical symptoms and tear film stability of DED patients; however, it has no significant efficacy on improving corneal injury and tear secretion, just the same as sodium hyaluronate eye drops. Nevertheless, moxibustion with walnut shell spectacles may have better effects on the self-assessment of ocular discomfort than sodium hyaluronate eye drops.

Current Advances in Mechanisms and Treatment of Dry Eye Disease: Toward Anti-inflammatory and Immunomodulatory Therapy and Traditional Chinese Medicine

Dry eye is currently one of the most common ocular surface disease. It can lead to ocular discomfort and even cause visual impairment, which greatly affects the work and quality of life of patients. With the increasing incidence of dry eye disease (DED) in recent years, the disease is receiving more and more attention, and has become one of the hot research fields in ophthalmology research. Recently, with the in-depth research on the etiology, pathogenesis and treatment of DED, it has been shown that defects in immune regulation is one of the main pathological mechanisms of DED. Since the non-specific and specific immune response of the ocular surface are jointly regulated, a variety of immune cells and inflammatory factors are involved in the development of DED. The conventional treatment of DED is the application of artificial tears for lubricating the ocular surface. However, for moderate-to-severe DED, treatment with anti-inflammatory drugs is necessary. In this review, the immunomodulatory mechanisms of DED and the latest research progress of its related treatments including Chinese medicine will be discussed.