Vascular endothelial growth factor production by isolated rat hepatocytes after cold ischemia-warm reoxygenation

Inflammatory disturbances in the liver microcirculation have been associate d with preservation injury of hepatic grafts. Vascular endothelial growth f actor (VEGF), a proinflammatory growth factor released by hepatocytes, acts on sinusoidal endothelial cells, but its implication in graft injury is st iff unclear. We studied VEGF production by rat hepatocytes after cold ische mia and warm reoxygenation and compared the capacity of University of Wisco nsin (UW) and sodium-lactobionate-sucrose (SLS) preservation solutions to m aintain this hepatocellular function. Isolated hepatocytes were kept for 0, 24, and 48 hours at 4 degreesC in either solution (cold ischemia), then in cubated for 1 to 24 hours at 37 degreesC (warm reoxygenation). We assessed cell viability and production of VEGF messenger RNA (mRNA) and protein. Cel l viability decreased in a linear time-dependent fashion by 10% after 48 ho urs of cold preservation and by an additional 40% after 24 hours of warm cu lture. Very little VEGF mRNA could be detected after up to 48 hours of simp le cold preservation in either solution. However, subsequent warm culture l ed to a robust and rapid increase in VEGF mRNA expression within the first hour, which declined to close to background levels within 8 to 12 hours in culture. This effect was more important in cells preserved in SLS than UW s olution. Similarly, cold preservation alone did not trigger VEGF secretion. VEGF secretion was detected after culturing hepatocytes at 37 degreesC and reached a maximal secretion rate within 12 to 15 hours. However, VEGF prod uction by preserved cells was reduced compared with unstored cells. In conc lusion, cold ischemia and warm reoxygenation triggers VEGF mRNA expression by hepatocytes, but subsequent VEGF secretion is partially impaired, sugges ting posttranslational defects.