Minimally invasive colorectal resection for benign pathology is associated with persistent proangiogenic plasma...

Minimally invasive colorectal resection for cancer is associated with increased plasma levels of numerous proangiogenic proteins for 3 to 4 weeks postoperatively, and plasma from postoperative weeks 2 and 3 stimulates proangiogenic endothelial cell behavior in vitro. It is unknown if similar plasma changes occur after minimally invasive colorectal resection for benign pathology.

The aim of this study is to assess 1) plasma levels of angiopoetin-2, placental growth factor, and soluble vascular cell adhesion molecule-1 after minimally invasive colorectal resection for benign pathology and 2) postoperative plasma's effects on in vitro endothelial cell proliferation (branch point formation), migration, and invasion.

Prospectively gathered plasma samples taken from patients undergoing colorectal resection who consented to participate in an institutional review board-approved plasma and data bank were used for ELISAs and in vitro endothelial cell studies.

The plasma and clinical data used were collected at 3 hospitals.

Patients undergoing minimally invasive colorectal resection for benign indications who were enrolled in a plasma/data bank and for whom adequate samples and volumes of plasma were available were included in the study.

Perioperative plasma levels of angiopoetin-2, placental growth factor, and soluble vascular cell adhesion molecule-1 were the primary outcomes measured. In vitro rates of endothelial cell branch point formation, migration, and invasion were determined after the addition of preoperative and postoperative plasma samples to endothelial cell cultures.

Plasma from 86 patients undergoing minimally invasive colorectal resection for benign indications was assessed (diverticulitis, 30; benign polyps, 56). Plasma levels of angiopoetin-2, placental growth factor, and soluble vascular cell adhesion molecule-1 were significantly increased for 3 to 4 weeks postoperatively compared with preoperative levels. In regard to the endothelial cell culture assays, significantly increased endothelial cell branch point formation, invasion, and migration results were noted with plasma from the second and third weeks postoperatively in comparison with preoperative culture results.

The weaknesses of this study are the limited numbers of late postoperative plasma samples and the need to bundle late samples into 7- to 12-day time blocks.

Minimally invasive colorectal resection for benign pathology is associated with persistent proangiogenic plasma alterations similar to those found in patients who have cancer. Surgical trauma and not the indication is the likely cause.