injurious in several situations including organ transplantation. Others and we have focused on transplantation purchase 1232416-25-9 studies in rodents to study IRI given the ready availability of the models and the importance of the Hexyl 5-aminolevulinate hydrochloride problem in clinical transplantation. There is strong evidence correlating IRI with later problems of organ graft survival. It has thus been in the interest of the transplant physician to overcome this problem. This has been especially true as the need for organs has expanded and the use of marginal donor organs continues to expand. Primary non-function after transplantation is a major problem and particularly in the instances of marginal donor organs, which suffer from significant damage due to IRI. It has long been accepted that ����pre-conditioning���� suppresses IRI. Pre-conditioning involves exposure of the recipient to donor cells or other substances, in low numbers/amounts, a few days prior to transplantation of the organ. Such manipulations have been shown to reduce IRI. While not well understood, there are a few reports that have shed light on the mechanisms by which pre-conditioning achieves its salutary effects. However, to date pre-conditioning has not found acceptance in clinical practice. Interestingly, some of the changes seen with preconditioning and to which success is attributed, are also seen when HO-1, CO or biliverdin are used as therapeutics. These include, among others, increases in anti-inflammatory cytokines such as IL-10, anti-apoptotic proteins, such as inhibitor of apoptosis and nuclear factor-kappa beta as well as heat shock proteins, such as HSP70. It may be that HO-1 induction or CO and biliverdin administration are effective because they mimic pre-conditioning, although there is no direct evidence for drawing any such parallels. We demonstrate here in a unique model of liver IRI in pigs that biliverdin suppresses IRI of the liver. Swine are an accepted species on the basis of studies in which human testing might be undertaken. Data show clear salutary effects and that biliverdin in every case, proved significantly beneficial in the majority of the tests we did. Biliverdin proved to be potent cytoprotective agent