Profiles of inflammatory cytokines following colorectal surgery: relationship with wound healing and outcome.

Inflammation is an essential component of normal wound healing. This study has correlated systemic (plasma) and local (wound fluid) concentrations of inflammatory cytokines (interleukin [IL]-6, tumor necrosis factor-alpha [TNF-alpha], and IL-1beta) with wound healing and surgical outcome following elective colorectal surgery. Paired plasma and wound fluid samples were collected (n = 44) postoperatively (days 1, 3, 5, 7) and analyzed by enzyme-linked immunosorbent assay (pg/mL). Cytokine levels were significantly greater in drain fluid than plasma on each postoperative day (POD); e.g., POD 1 : IL-6; drain fluid, median, 77,050 pg/mL (range 9,928-456,408); plasma, 241 pg/mL (22-1,333). Daily profiles of IL-6 and TNF-alpha were similar in drain fluid and plasma; IL-6 levels peaked on POD 1 decreasing to POD 7, and TNF-alpha levels increased from PODs 1 to 7. However, IL-1beta in plasma peaked on POD 1 and plateaued, whereas drain fluid showed two peaks (PODs 1 and 7). Only plasma levels of cytokines correlated to clinical parameters; IL-6 levels significantly correlated with postoperative complications; e.g., POD 5, complications 92(1-597) and no complications, 14(2-217). IL-6 also correlated with tumor pathology (Dukes stage, tumor depth, vascular invasion), and TNF-alpha levels correlated with the estimated blood loss during surgery. We conclude that local wound levels of cytokines correlated with the stage of wound healing, whereas systemic levels correlated with postoperative complications and tumor pathology.