Subconjunctival use of allogeneic mesenchymal stem cells to treat chronic superficial keratitis in German shepherd dogs: Pilot study.

Background: Chronic superficial keratitis (CSK) is an ocular condition in dogs characterized by corneal opacification leading to visual function impairment. Control of this chronic condition requires the use of topical immunomodulators or corticosteroids daily. Regenerative medicine has shown promising results in several fields of medicine. Aim: The aim of this study was to evaluate the clinical effect of allogeneic mesenchymal stem cells (MSCs) of adipose tissue applied via subconjunctival in dogs with CSK. Methods: A series of cases of eight dogs diagnosed with CSK were divided into two groups, four dogs each; the conventional treatment group received prednisolone 1% as topical eye drops and the experimental group (EG) received allogeneic MSCs transplantation. The dogs had not previously been treated for CSK. Systemic and ophthalmologic examinations were performed to exclude other abnormalities. An administered amount of MSC (1 × 106 cells each time) was injected via subconjunctival in the peri-limbal region at 0 and 30 days. The animals were followed for 110 days for clinical evaluation, and, at the same time, the images of the corneal abnormalities were obtained and analyzed in the ImageJ software. The statistical analysis was performed in the GrandPrism 7.0 software. Results: Initial and final images revealed that areas with neovascularization, inflammatory infiltrate, and opacity regressed in most eyes in both groups (7/8 eyes in each group) at the end of the 110 days, p = 0.0391 and p = 0.0078 respectively, but this response was minor in the EG comparing to conventional group (CG) (p = 0.026). No local or systemic side effects were observed. Conclusions: Despite the small melioration, MSCs treatment suggests clinical improvement in patients with CSK after 110 days without any local or systemic side effects. However, the improvement achieved was significantly less than the observed within CG. Further studies still are needed to evaluate the use and benefits of stem cells as an adjunct treatment for CSK.

Reduction in the inflammatory markers CD4, IL-1, IL-6 and TNFα in dogs with keratoconjunctivitis sicca treated topically with mesenchymal stem cells.

Keratoconjunctivitis sicca (KCS) is of predominantly immune-mediated origin. Dogs are an excellent model for understanding this disease, as the origin of KCS in dogs is like that in humans. The objective of this study was to localize and quantify immunological markers, such as CD4 lymphocytes, interleukin (IL)-1, IL-6 and tumor necrosis factor alpha (TNFα), before and after topical treatment with mesenchymal stem cells (MSCs). Twenty-two dogs positive for KCS were topically treated with 50 µL (1 × 106 MSCs) in the conjunctival sac and were evaluated for 6 months. The levels of the markers CD4, IL-6, IL-1 and TNFα were analyzed in conjunctival biopsy and cytology of the third eyelid gland by immunohistochemistry and immunocytochemistry. The results showed that before treatment, there was marked expression of all the markers (CD4, IL-6, IL-1 and TNFα), and after 6 months, there were significant (p < .05) reductions in the expression levels of all the markers. These results demonstrated that topical MSC treatment promotes a significant decrease in the expression levels of these inflammatory markers and could be used as adjuvant therapy in the treatment of KCS in dogs and humans. In addition, these markers can be excellent tools for diagnosing and analyzing the progression of KCS.