Circulating matrix metalloproteinase-9 is transiently elevated after colorectal surgery

Background and aims. Plasma levels of matrix metalloproteinases (MMPs) may yield important information in patients suffering from colorectal cancer but the effect of surgery, a common treatment modality in these patients, on circulating MMP levels is currently unknown. The aim of this study was to assess whether plasma MMP-2 and MMP-9 levels are affected by operative procedures. Materials and methods. In total 128 patients undergoing elective surgery for colorectal cancer (n=66), liver metastases from colorectal origin (n=50) and arthrosis of the hip (n=12) were included in the study. Gelatinase activity was measured, using quantitative gelatin zymography, in plasma obtained before operation and 1 week, 1 month and 3 months postoperatively. Results. One week after operation a significant increase in proMMP-9 activity was measured after colorectal surgery (260%, p =0.0038), liver surgery (285%, p <0.0001) and hip surgery (217%, p =0.012) as compared with preoperative levels. After 1 month proMMP-9 activity had returned to preoperative levels. No effect on proMMP-2 activity was measured. Conclusion. Operative procedures have a profound but transient effect on plasma MMP-9 activity. If used to assess disease status, postoperative plasma MMP levels should be interpreted with caution.