Human liver quality is a dominant factor in the outcome of in vitro studies

Donated human liver in the form of precision-cut tissue slices or isolated hepatocytes, is increasingly being used to predict metabolism and toxicity of xenobiotics in man. These tissue slices or hepatocytes can also be cold- preserved and cryopreserved to prolong their use for biological experiments . The viability of human liver could substantially affect the outcome of su ch experimentation. The goal of this investigation was to assess the viabil ity of donated human livers, in the form of tissue slices, as they were rec eived and to determine how varying degrees of liver quality affect experime ntal outcomes. Over one hundred human livers were categorized according to initial viability, as assessed by ATP content, K+ retention, protein synthe sis, and LDH leakage. Each liver was placed in a low-, a medium-, or a high -quality group. The results showed that 76% of transplant-grade tissue (pro cured for transplantation) fell into the high-viability classification whil e the majority of research-grade tissue (not procured for transplantation) fell into the lowest viability classification. It was also found that only tissue slices prepared from highly viable human liver could be cold-preserv ed and cryopreserved. Dichlorobenzene metabolism was also greater in slices from highly viable human livers as compared to less viable livers. This st udy showed that human liver tissue acquired for medical research substantia lly varies in its viability and that these differences will affect the expe rimental data obtained.