Previous studies have determined that proteases are important in cold preservation injury to the liver. The purposeCold preservation injury to the liver primarily affects sinuof this study was to determine the role of matrix metallopro-soidal endothelial cells.1 These cells have a tubular morpholteinases (MMPs) in cold preservation injury. Effluents were ogy and form the actual blood channel. Because of the need collected from rat livers after various periods of preservation to transfer large molecules between the blood and the hepatoeither in Eurocollins solution or in University of Wisconsin cyte cell membrane, sinusoidal lining cells do not lie on a (UW) solution. Effluents were also collected from 17 human basement membrane, but are supported by a porous matrix, donor livers stored in UW solution. To determine whether consisting of cords of collagen linked to the cells through sinusoidal endothelial cells released MMPs when placed in intermediate molecules such as fibronectin. In the cold, the the cold, these cells were isolated from rat livers and cultured sheet-like cytoplasm of these cells retracts from its attachat 4ЊC. Gelatin zymography, quantitative assay of gelatinolytic ment to the sinusoidal wall, and the tubular cell becomes activity, immunoprecipitation, and Western blotting were spheroidal, 1 apparently connected to matrix only by isolated used to identify metalloproteinases and to measure their activ-cords of cytoplasm.
ity. Human and rat liver effluents contained gelatin-digestingWhen the liver is reperfused after prolonged storage peribands on zymography. Their appearance was inhibited by ods, sinusoidal lining cells die.3 At shorter but still clinically specific metalloproteinase inhibitors and also by lactobionate, relevant times of preservation, a different set of events ensues the major ingredient of UW solution. The most prominent on reperfusion. The cytoplasm begins to extend out to rebands in humans and the rat appeared at approximately 72 cover the denuded matrix and liver cells. 4 Nonetheless, imkd and 92 kd, suggesting that they were the MMPs 72-kd mediately after perfusion, there is exposed matrix, a condigelatinase and 92-kd gelatinase. Supernatants of isolated rat tion that may contribute to the well-described platelet 5,6 and sinusoidal endothelial cells stored in the cold contained simi-white cell adhesion 7-9 that occurs on reperfusion. Hence the lar bands. In the rat, the proteinases were present in both structural alterations during cold preservation likely contriblatent and active forms, but, in humans, predominately the ute to the ultimate injury on reperfusion. latent form was seen. In humans, there were four prominent The structural changes induced by cold must involve alterbands in the gelatin zymography. By immunoprecipitation, ations in the cellular cytoskeleton, as well as in the connectwo of the bands were identified as the 92-kd gelatinase and tions between cell and matrix. Indeed, Hall et al. showed a dimer or polymer of 92-kd gelatinase. Using Western blot-that ...
