MMP expression increases during anastomotic healing and correlates with anastomotic leakage.

(A) The photoprobe AF443-Cy5.5 was injected 24h prior to analysis and was detected with significantly increased intensity on the later postoperative days (SNR, POD5 vs. POD1, p <0.0001). (B) Using immunostaining MMP-9 expression can be localized within the anastomotic tissue as well as the perianastomotic inflammatory exudate with increased expression beginning on POD3. Scale bar 150 μm. (C) Immunostaining was corroborated using gelatin zymography. As shown in the gel, elevated expression and activity of MMP-2 and -9 can be detected beginning on POD3. (D) In comparison within the leakage groups (0 = no leakage; 1 = leakage) the leakage group showed significantly higher uptake of the tracer in ex vivo analysis (SNR: vs. 37.37± 3.63 vs. 26.16 ± 3.635, p = 0.0369).