Cold preservation of isolated sinusoidal endothelial cells in MMP 9 knockout mice: effect on morphology and platelet adhesion.

Cold preservation of rat sinusoidal endothelial cells causes actin disassembly, cell rounding, matrix metalloproteinase (MMP) secretion, and platelet adhesiveness. Studies in rats suggest that gelatinases MMP2 and MMP9 are the key mediators of the injury. We created a model of cold preservation injury in mouse sinusoidal endothelial cell (MSEC) to examine the effect of cold on MSEC, specifically on MSEC from genetically deleted mice (MMP9/KO) mice. MSEC were isolated from wild-type and MMP9/KO mice and cold preserved for up to 24 hours. MMP activity was measured in culture supernatants and in effluents from preserved whole mouse livers. Cellular and actin morphology were studied by light and fluorescence microscopy. A platelet-MSEC adhesion assay was performed. Yield, growth, and appearance of MSEC were similar in wild-type and MMP9/KO mice. Cold-preserved wild-type MSEC exhibited actin disassembly and cell rounding as in the rat but at a much slower rate. These morphologic cell changes were attenuated in MSEC from MMP9/KO mice. Both MMP2 and MMP9 were present in liver effluents of wild-type mice, but MMP9 was absent in effluents from MMP9/KO mice. Total MMP activity in culture supernatants was greater after preservation in wild-type than in MMP9/KO mice. There was significantly more platelet adhesion to wild-type MSEC than to MSEC from MMP9/KO mice. In conclusion, MSEC is an excellent model system for the study of cold preservation injury. Injury is similar to rat sinusoidal endothelial cells but delayed. MMP9 is a key mediator of the cold preservation injury.