Increased growth factor expression after hepatic and pancreatic resection

Removal of the primary tumour is suggested to associate with an enhanced tumour growth of residual micrometastases. Recent data focus on growth factors that may be released in response to surgery-stimulating receptors of residual tumour cells. Vascular endothelial (VEGF) and hepatocyte growth factor (HGF) are potent inducers of angiogenesis. The two factors are necessary for wound healing and the promotion of tumour growth. This study was designed to determine growth factor serum levels in patients before, during and after major abdominal surgery. It was recently shown that simultaneous hepatic and pancreatic resection led to poor liver regeneration. As growth factors may be involved in these findings we compared the growth factor levels after liver resection with the levels in patients after pancreatic resection. Forty patients were accrued before hepatopancreatic surgery (hepatic resection n=20 and pancreatic resection n=20). Blood samples were taken from each patient immediately prior to surgery, during the operation and on the postoperative days (POD) 1-3, 5 and 10. To examine the wound fluid, liquid from the wound drains was collected on POD 3. Using ELISA the concentration of the angiogenic cytokines HGF and VEGF165 was determined. After the liver and pancreatic resections, circulating HGF and VEGF165 were increased. We found significantly higher levels of HGF on POD 1-3 (p<0.01), compared to preoperative results with a peak on POD 2. After measuring the postoperative VEGF165 levels we found significantly higher levels of circulating VEGF165 on POD 1-5 (p<0.01) compared to the preoperative levels. On comparing liver with pancreatic resection we did not detect significantly different levels of the two growth factors in the two groups. VEGF165 and HGF concentrations measured during the operation demonstrated no change. HGF and VEGF165 levels detected in the wound fluid on POD 3 were approximately 10 times higher than the preoperative serum levels, respectively. In summary, our data show increased VEGF165 and HGF levels after hepatopancreatic surgery. Notably, the lack of an impact of the type of organ resection on the concentration-time curve of the two growth factors suggest that high postoperative growth factor levels are part of normal wound healing and systemic inflammation. Thus, the proangiogenetic potential of growth factors may account for accelerated tumour growth when residual tumour cells are exposed to high levels of VEGF165 and HGF.