Cold preservation-warm reoxygenation increases hepatocyte steady-state Ca and response to Ca-mobilizing agonist AZIZ ELIMADI AND PIERRE

Elimadi, Aziz, and Pierre S. Haddad. Cold preservation-warm reoxygenation increases hepatocyte steady-state Ca21 and response to Ca21-mobilizing agonist. Am J Physiol Gastrointest Liver Physiol 281: G809–G815, 2001.— Although the role of Ca21 in liver transplantation injury has been the object of several studies, direct evidence for alterations in intracellular Ca21 homeostasis after cold preservation-warm reoxygenation (CP/WR) has never been presented. We thus investigated the effects of CP/WR on steady-state Ca21 and responses to a Ca21-mobilizing agonist. Isolated rat hepatocytes were suspended in University of Wisconsin solution, stored at 4°C for 0, 24, and 48 h, and reoxygenated at 37°C for 1 h. Cytosolic Ca21 was measured in single cells by digitized fluorescence videomicroscopy. CP/WR caused a significant increase in steady-state cytosolic Ca21, which was inversely proportional to cell viability. Pretreatment of hepatocytes with an agent that protects mitochondrial function attenuated the increase in steady-state cytosolic Ca21 and improved hepatocyte viability. Ca21 responses to the purinergic agonist ATP also increased significantly as a function of cold storage time. This increase was related to an increase in the size of inositol 1,4,5-trisphosphate-sensitive Ca21 stores and subsequent capacitative Ca21 entry. Thus CP/WR significantly perturbs steady-state hepatocellular Ca21 and responses to Ca21-mobilizing agonists, which may contribute to hepatocyte metabolic dysfunction observed after CP/WR.