MMP9 and cholesteryl ester measurement: In the duodenum, dogs with CE compared to healthy dogs had a significantly higher number (and percentage) of samples positive for mucosal pro-MMP-2 (32/35 [91.4%] vs. 3/18 [16.7%]; P < 0.0001), active MMP-2 (10/35 [28.6%] vs. 0/18 [0%]; P = 0.011), and pro MMP-9 (34/35 [97.1%] vs. 10/18 [55.6%]; P = 0.0004) (Fig. 3).