Influence of postoperative acute-phase response on angiogenesis and tumor growth: Open vs. laparoscopic-assisted surgery in mice

Inflammatory responses and tumor growth are increased after laparotomy compared with laparoscopy in some animal models. Proinflammatory cytokines interleukin-6 (IL-6) and interleukin-1 beta (IL-1beta) upregulate the expression of vascular endothelial growth factor (VEGF). Our aim was to investigate the influence of postoperative inflammatory responses on angiogenesis and tumor growth. 5 x 10(6) B51LiM cells were injected into the cecal wall of Balb/c mice. After 2 weeks, the animals were randomized into the following three groups: open cecectomy (OC), CO2-laparoscopic-assisted cecectomy (LC), and helium-laparoscopic-assisted cecectomy (LH). On postoperative day 12, the mice were killed. Turnor load scores and weight were significantly greater after laparotomy than after laparoscopy. Serum IL-6 levels 6 hours after surgery (OC: 4157 +/- 1297 pg/ml vs. LC: 2514 +/- 1417 pg/ml vs. LH: 2255 +/- 1714 pg/ml) and VEGF levels on postoperative day 12 (OC: 231 +/- 125 pg/ml vs. LC: 45 +/- 9 pg/ml vs. LH: 49 8 pg/ml), measured by enzyme-linked immunosorbent assay, were significantly higher in the laparotomy group. Microvessel density was also significantly higher in the OC group (OC: 34.3 +/- 11.5 vs. LC: 15.5 +/- 12.5 vs. LH: 18.5 +/- 11.9). There was a positive correlation between IL-6 and VEGF postoperative serum levels (rho = 0.67; P < 0.001). We concluded that increased systemic levels of proinflammatory cytokines and VEGF are associated with increased angiogenesis and tumor growth after laparotomy compared to laparoscopy in mice. (C) 2003 The Society for Surgery of the Alimentary Tract, Inc.