The cytokine cascade in controlled abdominal trauma

Introduction: Following traumatic injury, the body rapidly initiates an inflammatory response with the release of the proinflammatory cytokines TNF-α, IL-1β and IL-6. IL-10 and IL-1ra are released as well and are representatives of anti-inflammatory cytokines. Excess inflammation results in secondary tissue injury. Elective surgery provides a controlled clinical model of trauma with the advantage of a defined time zero. Thus, in this study we are comparing the systemic cytokine response of a laparoscopic inguinal hernia repair (LIH) versus a hemicolectomy (HC). Methods: During a two year period, we prospectively studied LIH patients (control group, n=6) and HC patients (study group, n=5). Their serum specimens were collected preoperatively and at specified time intervals for the next 24 hours. The samples were then centrifuged and frozen at -70 degrees Celsius. Cytokine analysis was conducted with electrochemi-luminescence (Orgin analyzer, Rockville, MD). Results: 3 of the control group had markedly elevated cytokines preoperatively and thus were excluded from the control group. The peak level of IL-6 occurred 2 hours after surgery in the HC group (peak= 120+205 pg/ml) and remained elevated over the next 22 hours (LIH group < 15 pg/ml, lower sensitivity of the test, p<0.05). IL-1ra in both groups of patients was significantly elevated from 15 minutes status post tissue resection (HC peak=1130+499 pg/ml, LIH peak=1147 + 1087) and stayed elevated for the next 24 hours. IL-1β was elevated at the 4 hour sample time in both groups (HC peak=57+61, LIH peak=67+100). In both groups TNF-α and IL-10 were not significantly elevated (peak <15 pg/ml). Conclusion: A significant level of trauma is required for the release of IL-6 and it may be responsible for the pro-inflammatory response seen in abdominal trauma. IL-1ra, an anti-inflammatory representative, is released in response to significant abdominal trauma. IL 1β is released in less significant trauma. IL-1β, TNF-α and IL-10 do not appear to play significant roles in controlled abdominal trauma.