Abstract
Purpose: :
Approximately 75% of dogs with diabetes mellitus (DM) develop cataracts within 1 year of the time of diagnosis. Similar cataracts rapidly form dogs fed a diet containing 30% galactose and these are reduced in a dose-dependent manner with the topical aldose reductase inhibitor KinostatTM. The purpose of this study was to investigate whether KinostatTM can similarly prevent or inhibit the progression of cataracts in naturally occurring diabetic dogs.
Methods: :
Forty dogs, newly diagnosed with DM and with minimal lens changes were enrolled in a prospective, masked pilot study. Dogs were randomly assigned a coded vial containing either KinostatTM or vehicle (placebo), with the contents of the vial (drug or placebo) masked from the examiner. Twenty-nine dogs received KinostatTM, and 11 dogs received placebo. Owners were instructed to administer the agent OU TID for 1 year, and were instructed to record each time of administration in order to ensure compliance. Complete ophthalmic examinations were performed prior to enrolling in the study, and then at 1, 2, 3, 6, 9, and 12 months after. Digital images were taken after dilation at each time interval. Complete blood chemistries, HbA1C, and Kinostat blood levels were obtained at 1 year.
Results: :
Cataract formation and progression was observed in 7/11 (64%) of the dogs receiving placebo with six dogs developing mature cataracts, and one dog developing equatorial vacuoles. Four dogs (36%) in the placebo group did not show evidence of cataract formation at the last follow up; however, the population variance of the placebo group was not significantly different (p<0.13). In contrast, cataract formation in the KinostatTM group was significantly (p<0.02) inhibited with 21/29 (72%) of dogs receiving KinostatTM not showing evidence of cataract development at the last follow up. Eight KinostatTM treated dogs (28%) developed cataracts; (3) incipient anterior cortical cataracts, (1) equatorial vacuoles, (4) mature cataracts. HbA1c values ranged from 8.4-12.3. KinostatTM blood levels were undetectable 1 year after treatment.
Keywords: cataract • diabetes • drug toxicity/drug effects