Serum vascular endothelial growth factor concentration in dogs diagnosed with chronic superficial keratitis

The objective of this study was to measure the vascular endothelial growth factor (VEGF) levels in dogs diagnosed with chronic superficial keratitis (CSK). The study was performed on 25 German shepherds (14 males and 11 females, aged between 3 and 11 years). The VEGF levels were determined in blood serum using commercially available enzyme-linked immunosorbent assay (ELISA; Quantikine Canine VEGF Immunoassay, R&D Systems). The test group of affected German shepherds was subdivided into two subgroups, based on the area of corneal neovascularisation. The first subgroup (9 patients) comprised dogs with neovascularisation observed in 1 to 2 quadrants of the right and left cornea, while the second subgroup (16 patients) comprised dogs with neovascularisation observed in 3 to 4 quadrants of the right and left cornea. The control group comprised 12 clinically healthy German shepherds (7 males and 5 females, aged between 3 and 9 years). The results were then statistically analysed by the Mann-Whitney test. The study indicated that the median serum VEGF concentration in healthy dogs was 14.9 pg/mL. The VEGF level observed in sick German shepherds was elevated (19.5 pg/mL) as compared to the values found in healthy dogs; however, a statistically significant increase in VEGF concentration, as compared to the values observed in healthy dogs, was only noted in the first subgroup, where the median VEGF concentration was 22.0 pg/mL. Elevated serum VEGF concentration was observed in German shepherds diagnosed with CSK. A statistically significant increase in VEGF levels was observed in dogs in the first stage of the disease, i.e. the early stage of neovascularisation.