RESUMO
Keratoconjunctivitis sicca (KCS) is a dysfunction in tear production associated with clinical signs, which include conjunctival hyperemia, ocular discharge, discomfort, pain, and, eventually, corneal vascularization and pigmentation. Immunosuppressive drugs are routinely administrated for long periods to treat KCS but with side effects and limited results. Evaluation of the clinical benefits of intralacrimal transplantation of allogeneic mesenchymal stem cells (MSCs) in dogs with mild-moderate and severe KCS was done. A total of 24 eyes with KCS from 15 dogs of different breeds were enrolled in the present study. A single transplantation of MSCs (1 × 106) directly into lacrimal glands (dorsal and third eyelid) was performed. The Schirmer tear tests (STTs) and ocular surface improvements were used to assess short- and long-term effects of these cells. The STTs were carried out on day 0 (before MSCs transplantation) and on days 7, 14, 21, and 28, as well as 6 and 12 months after MSC transplantation. Our data demonstrate that allogeneic MSC transplantation in KCS dogs is safe since no adverse effects were observed immediately after transplantation and in short- and long-term follow-ups. A statistically significant increase in the STT and ocular surface improvements was found in all eyes studied. In all the eyes with mild-moderate KCS, STT values reverted to those of healthy eyes, while in eyes with severe KCS, although complete reversion was not found, there was improvement in tear production and in other clinical signs. Our study shows that a single dose of a low number of MSCs can be used to treat KCS in dogs. In contrast to immunosuppressive drug use, MSC transplantation has an effect over a long period (up to 12 months), even after a single administration, and does not require daily drug administration.
RESUMO
PURPOSE: To verify the safety and efficacy of botulinum toxin type A (BoNT/A) to promote protective ptosis in dogs. METHODS: In this prospective interventional study, a total of 10 dogs underwent transcutaneous anterior chemodenervation of levator palpebral superioris with 15 U of BoNT/A. The systemic changes, ocular mobility, visual function, intraocular pressure (IOP), tear production, and the onset, degree, and duration of ptosis were evaluated on a daily basis during the first 7 days and on days 14, 21, and 28 after application. RESULTS: The onset of the clinical effect was observed between 2 and 3 days after application of the toxin; the time taken for maximum ptosis to develop varied from 4 to 7 days (mean 5 days) and the average duration of the toxin effect was 21 days. The mean percentage reduction in palpebral fissure height was 42.859% (SD±35.714%-59.821%). There was not a statistically significant difference in IOP before and after the BoNT/A application (P=0.974), or lacrimal production evaluation (P=0.276). There was no change in ocular mobility and no other adverse effect was observed in association with the administration of the study drug. CONCLUSION: The application of BoNT/A into the levator palpebral superioris muscle in dogs was effective and safe to promote protective ptosis with a temporary covering of the cornea.
