Major Open Colorectal Surgery Is Associated with Proangiogenic Plasma Compositional Changes: Plasma From Patients Undergoing Open Cancer Resection Stimulates in Vitro Endothelial Cell Growth, Invasion, and Migration

HMC Shantha Kumara HMC, PhD, Daniel Kirchoff, MD, Joonho Jang, MD, Xiaohong Yan, PhD, Micheal Grieco, MD, Vesna Cekic, RN, Richard R Whelan, MD. St Luke Roosevelt Hospital Center,Department of Colon and Rectal Surgery, NY,New York 10019, USA

Introduction: Minimally invasive colorectal resection (MICR) is associated with unique plasma elevations of the proangiogenic proteins VEGF, Angiopoetin-2 (Ang-2), soluble VCAM, and placental growth factor (PlGF) that persist for 2 to 4 weeks. In addition, in vitro Endothelial Cell (EC) assays carried out with plasma from the second and third weeks after MICR have shown that EC proliferation, migration, and invasion (critical to new blood vessel formation) are significantly increased when compared to results obtained with preoperative (PreOp) plasma. Thus MICR is associated with persistent proangiogenic blood protein changes that may stimulate the growth of residual tumor after cancer resection. The purpose of this study was to determine whether postoperative (postop) plasma from open colorectal resection patients has similar proangiogenic effects on EC’s in culture.
Methods: Plasma for this study was obtained from an IRB-approved perioperative plasma and data bank; only cancer patients who underwent elective open colorectal resection were eligible. Blood samples had been obtained PreOp and at varying postop time points and had been stored at -800C. Only patients for whom PreOp and, at least, one postop plasma sample between POD 7 and POD 33 were available were eligible. Late samples were bundled into 7-13 day time periods and considered as single time points. In vitro cultures of human umbilical venous endothelial cells (HUVEC’s) were used for the proliferation assays (branch point formation, (BP), invasion (INV), and migration (MIG)) which were carried out with the PreOp, POD 7-13, POD 14-20, and POD 21-33 plasma samples. Data was analyzed by paired t-test and reported as mean ± SD for each parameter for each time point (significance, p<0.05).
Results: Plasma samples from a total of 54 patients were utilized (mean age,64.6±13.3 Years; male: female, 28/26). The plasma from a different population was used for each comparison (PreOp vs. POD7-13, n=30; PreOp vs. POD14-20, n=26; and PreOp vs POD21-33, n=17, etc) based on postop plasma availability. The breakdown of operations for the overall group was: Right, 18%; transverse, 6 %; left,15%; sigmoid, 11%; and rectal, 50%. The mean rate of EC proliferation was significantly greater for both the POD7-13 (p=0.0001), and POD14-20 (p=0.0001) groups when compared to results obtained with their respective preoperative plasma samples. Similarly, significantly greater EC invasion and migration was noted on POD7-13 and POD 14-20 vs. the preop plasma results (p value=0.0001 for all comparisons). In contrast, there was no significant difference in BP, INV, or MIG for the POD21-33 group when compared to their PreOp results.
Conclusion: Plasma from the second and third weeks after open colorectal cancer resection significantly stimulates in-vitro EC proliferation, invasion, and migration. No differences were noted for the POD21-33 time block. As mentioned, very similar results were obtained with plasma samples from MICR patients. At least as regards postoperative proangiogenic plasma effects, open and closed surgical methods are quite similar. Following both types of surgery tumor angiogenesis may be stimulated for up to 3 weeks. Further studies are warranted.

Session: Poster
Program Number: P139
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