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

Abstract

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 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 8 dogs diagnosed with CSK were divided into 2 groups, 4 dogs each, the conventional treatment (CT) 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 (1x106 cells each time) were injected via subconjunctival in the peri-limbal region at 0 and 30 days. The animals were followed for 110 days to 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 CT (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 CT group. Further studies still are needed to evaluate the use and benefits of stem cells as an adjunct treatment for CSK.