The omentum is a site of stromal cellderived factor 1α production and reservoir for CXC chemokine receptor 4positive cell recruitment

Background: The mechanism of the omental response to injury remains poorly defined. This study investigates the omental reaction to a foreign body, examining the role of a chemokine ligand/receptor pair known to play a crucial role in angiogenesis and wound healing. Methods: A ventral hernia, surgically created in the abdominal wall of 6 swine, was repaired with silicone sheeting to activate the omentum. Omental thickness was determined by ultrasonography. Serial stromal cellderived factor 1α (SDF-1α) concentrations were measured in blood, wound, and peritoneal fluids by enzyme-linked immunosorbent assay. Results: During the 14-day study period, serial ultrasonography showed a 20-fold increase in omental thickness, and enzyme-linked immunosorbent assay revealed a 4-fold increase in SDF-1α concentration in local wound fluid. Omental vessel count and vascular surface area were 8- to 10-fold higher in reactive omentum. Immunohistochemistry showed nearly complete replacement of control omental fat with CXC chemokine receptor 4 (CXCR4)-positive cells by day 14. Conclusions: Activated omentum, important in the SDF-1α/CXCR4 axis, may serve as an intraperitoneal reservoir for recruitment of circulating bone marrowderived cells vital to healing.