Vascular endothelial growth factor concentrations in dogs with spirocercosis.

Abstract

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent proangiogenic factor associated with tumor development. Spirocerca lupi is a nematode of canids that induces an esophageal nodule that progresses to a sarcoma in 25% of cases. Determination of neoplastic transformation is challenging and usually based on endoscopy-guided biopsies under general anesthesia, an expensive procedure that often yields nondiagnostic, necrotic samples. HYPOTHESIS: Circulatory VEGF concentrations are increased in dogs with neoplastic spirocercosis and can distinguish between dogs with neoplastic and nonneoplastic disease. ANIMALS: A total of 24 client-owned dogs, 9 nonneoplastic, 9 neoplastic, and 6 controls. METHODS: Case-control study. Plasma and serum VEGF concentrations at the time of diagnosis were compared with those of healthy controls. Measurement of VEGF was performed using a canine-specific ELISA. Kruskal-Wallis and Dunn's tests were used for statistical analysis with significance set at P < .05. RESULTS: The median plasma VEGF concentrations of dogs with neoplastic spirocercosis were 629 pg/mL (range, 282-2,366) higher than both the nonneoplastic (<39.5 pg/mL; range, <39.5-716) and control dogs (<39.5 pg/mL; all values, <39.5; P = .0003). The median serum VEGF concentration of the neoplastic dogs was 69 pg/mL (range, <39.5-212) higher than the nonneoplastic (<39.5 pg/mL; range, <39.5-44.13) and control dogs (<39.5 pg/mL; all values, <39.5; P = .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Both plasma and serum VEGF concentrations can be used to differentiate nonneoplastic and neoplastic spirocercosis. The role of VEGF in neoplastic transformation of S. lupi-induced nodules and the potential utility of anti-VEGF drugs in spirocercosis-induced sarcoma warrant further investigation.