Differential Production of Cytokines Following Colorectal Surgery

BACKGROUND: Colorectal surgery is associated with a number of postoperative complications, including anastomotic leak and local recurrence. These complications are more common after rectal surgery than after colon surgery. Cytokines are secreted into the peritoneal cavity after colorectal surgery and have a number of metabolic and immunological effects. Hence we suggested that differential secretion of these may contribute to the differences in complications between colon and rectal surgeries. METHODS: Patients undergoing either elective rectal excision or colectomy for benign or malignant disease were recruited into the study. The region in relation to the anastomosis was drained with a silastic drain for 12-18 h. Drain fluid was collected on the morning following surgery. The drain fluid was assayed for interleukin (IL)-1beta, tumour necrosis factor-alpha, IL-6, IL-8, IL-10 and IL-13 using multiplexed biomarker immunoassays. RESULTS: Interleukin-8 concentrations were significantly higher in the region of the anastomosis after rectal excision compared with colectomy. Also, IL-6 levels were very high in both groups, but there was no significant difference between the groups. Although the concentrations of IL-10 were higher in the rectal group relative to the colectomy group, only low levels of this cytokine were present in the drain fluids. No other cytokines were consistently detected in significant concentrations. CONCLUSION: This study has shown that the concentration of IL-8 in the region of the anastomosis of patients who have undergone rectal surgery is much higher than those who have undergone colonic surgery. The increased level of IL-8 may provide a milieu conducive to local recurrence and anastomotic leak.