Clinical Outcomes of Stem Cell Therapy in Dogs With Keratoconjunctivitis Sicca; A Systematic Review and Meta-Analysis

Keratoconjunctivitis sicca (KCS) results from a deficiency in the pre-corneal tear film, causing persistent ocular discomfort and a predisposition to ocular surface diseases. Current treatments, including topical lacrimostimulants and lacrimomimetics, primarily offer symptomatic relief without restoring lacrimal gland function. Mesenchymal stem cell (MSC) therapy, with its regenerative and immunomodulatory properties, has been investigated in preclinical and veterinary studies but remains critically underexplored for its clinical relevance in treating KCS.

A systematic review was conducted on April 24, 2024, using Medline, Embase, Web of Science, and CABI databases. Studies evaluating MSC therapy in dogs and cats with KCS were included. Data collected included demographic information, baseline and post-treatment Schirmer tear test (STT) values, and ocular symptoms such as discharge, conjunctival hyperemia, and corneal changes. The risk of bias was assessed using validated tools, and the quality of evidence was graded using the Oxford Centre for Evidence-Based Medicine (OCEBM). Statistical analyses were performed with STATA to compare STT values at baseline and after 1- and 6-month follow-ups.

Six studies involving 151 eyes from 98 dogs were included. Studies demonstrated low to moderate risk of bias, and evidence quality was graded as level C. MSC therapy significantly increased tear production and improved ocular comfort, with mean STT increases of 0.68 mm/min at 1 month and 1.51 mm/min at 6 months.

MSC therapy offers statistically significant improvements in tear production in dogs with KCS and is considered a safe treatment option. However, the modest clinical significance highlights the need for further research to confirm its efficacy.