Monocyte chemotactic protein-1 in a randomized placebo-controlled study of canine plasmacytic-lymphocytic colitis

The purpose of this study was to determine serum and colonic monocyte chemotactic protein-1 (MCP-1) concentration in dogs with plasmacytic-lymphocytic (PL) colitis, as well as to demonstrate if the concentration of MCP-1 may be an accurate diagnostic and prognostic marker for PL colitis in dogs receiving three different therapeutic protocols. Serum and colonic MCP-1 concentration were measured in 18 dogs with PL colitis and in 6 controls. Dogs with PL colitis were randomly divided in 3 groups and for a period of 30 days received the following: Group 1, sulfasalazine, prednisone and placebo; Group 2, placebo and Omega3/Omega6 fatty acids, and Group 3, sulfasalazine, prednisone and Omega3/Omega6 fatty acids. Colonic and serum MCP-1 concentration were determined at the beginning and at the end of this period. Serum MCP1 concentrations at the beginning were not significantly increased in dogs with PL colitis compared to the controls. On the contrary, colonic tissue MCP-1 concentrations at the beginning were significantly increased in the same dogs compared to the controls. Moreover, the colonic tissue MCP-1 concentration in the dogs of group 3 was significantly decreased (P<0.001) at the end of the experiment. The same observations were obtained from dogs of groups 1 and 2, in which the colonic MCP-1 concentration also significantly decreased (P<0.01). These data demonstrate that in canine PL colitis, colonic MCP-1 concentration is increased in comparison to those of controls and suggest that the colonic MCP-1 concentration may aid in the diagnosis of canine PL colitis.