Organ Preservation into the 2020s: The Era of Dynamic Intervention.

Organ preservation has been of major importance ever since transplantation developed into a global clinical activity. The relatively simple procedures were developed on a basic comprehension of low-temperature biology as related to organs outside the body. In the past decade, there has been a significant increase in knowledge of the sequelae of effects in preserved organs, and how dynamic intervention by perfusion can be used to mitigate injury and improve the quality of the donated organs. The present review focuses on (1) new information about the cell and molecular events impacting on ischemia/reperfusion injury during organ preservation, (2) strategies which use varied compositions and additives in organ preservation solutions to deal with these, (3) clear definitions of the developing protocols for dynamic organ perfusion preservation, (4) information on how the choice of perfusion solutions can impact on desired attributes of dynamic organ perfusion, and (5) summary and future horizons.

Capacity of bioregulators of stem and progenitor cells to strongly affect liver redox-dependent processes.

Abstract Effects of stem and progenitor cells or their compounds on recipient cells are investigated intensively today. In spite of this, their ability to interact with native cells and the final targets affected by them, particularly biochemical parameters that characterize cell redox-dependent processes, remain little studied. We have studied how bioregulators of stem and progenitor cells affect these processes in freshly isolated liver after animal pretreatment in vivo. Cytosol of human fetal mesenchymal-mesodermal tissues (8-10 weeks gestation) was administered intravenously; the control group was treated with Hanks' solution. After 4 hr, rats were sacrificed and their livers were isolated. To evaluate liver redox-dependent state, mitochondrial respiratory activity and nitroxyl radical and Alamar Blue™ reduction rates, mitochondrial and cytosolic glycerol kinase and nicotinamide adenine dinucleotide (NADH)-dependent malate dehydrogenase activities were studied. The results obtained demonstrate that bioregulators strongly affect liver redox-dependent processes, increasing mitochondrial respiration in state III and spin probe reduction rate and enhancing Alamar Blue™ reduction by glycolytic and nonglycolytic postmitochondrial enzymes. In addition, mitochondrial glycerol kinase and both isoforms of NADH-dependent malate dehydrogenase were inhibited. These data bring us closer to understanding stem and progenitor cell effects via directed regulation of metabolic redox-dependent processes.

Organ Preservation: Current Concepts and New Strategies for the Next Decade.

SUMMARY: Organ transplantation has developed over the past 50 years to reach the sophisticated and integrated clinical service of today through several advances in science. One of the most important of these has been the ability to apply organ preservation protocols to deliver donor organs of high quality, via a network of organ exchange to match the most suitable recipient patient to the best available organ, capable of rapid resumption of life-sustaining function in the recipient patient. This has only been possible by amassing a good understanding of the potential effects of hypoxic injury on donated organs, and how to prevent these by applying organ preservation. This review sets out the history of organ preservation, how applications of hypothermia have become central to the process, and what the current status is for the range of solid organs commonly transplanted. The science of organ preservation is constantly being updated with new knowledge and ideas, and the review also discusses what innovations are coming close to clinical reality to meet the growing demands for high quality organs in transplantation over the next few years.

Reversible mitochondrial uncoupling in the cold phase during liver preservation/reperfusion reduces oxidative injury in the rat model.

Reversible uncoupling of the mitochondrial electron-transport chain may be one strategy to prevent intracellular oxidative stress during liver cold preservation/warm reperfusion (CP/WR) injury. 2,4-Dinitrophenol (DNP) is a potent water-soluble uncoupling agent for supplementation of the hepatic CP solution. The aim of this work was to investigate the possible influence of DNP in the CP solution on the isolated rat liver state during CP/WR. Livers were subjected to CP at 4 degrees C in sucrose-phosphate based solution (SPS) for 18 h, followed by WR for 60 min in vitro. The final concentration of DNP was 100 microM. DNP presence during the CP stage led to partial ATP level decrease accompanied by a significant diminution in liver TBARS and a prevention of antioxidant enzyme activity decrease (catalase, GSH-PO, GSH-Red) when compared with livers stored without DNP. After DNP wash-out during WR, an improvement in the mitochondrial functional state (higher respiratory control indices and ATP levels, and a decrease in V(4) respiration rates) were observed. This was concurrent with lower TBARS levels, higher antioxidant enzyme activities and significant increase of bile production. The results suggest that reversible uncoupling may be one way to influence oxidative stress associated with hepatic cold preservation.

Functional hepatic recovery after xenotransplantation of cryopreserved fetal liver cells or soluble cell-factor administration in a cirrhotic rat model: are viable cells necessary?

BACKGROUND AND AIM: Chronic liver failure results in the decrease of the number of functioning hepatocytes. It dictates the necessity of using exogenous viable cells or/and agents that can stimulate hepatic regenerative processes. Fetal liver contains both hepatic and hematopoietic stem cells with high proliferative potential, which may replace damaged cells. Also, immature cells produce fetal-specific factors which may support the injured liver. Our aim was to test the ability of human fetal liver cells and cell-free fetal-specific factors of non-hepatic origin to stimulate recovery processes in an experimental model of carbon tetrachloride-induced cirrhosis in rats. METHODS: Cirrhotic rats were intrasplenically injected with fetal liver cells (1 x 10(7) cells/0.3 mL medium) or cell-free fetal-specific factors (0.3 mL/1 mg protein). Control groups received medium alone. Serum indexes, hepatic functions, and morphology were evaluated for 15 days. RESULT: Human fetal liver cell transplantation was shown to abrogate the mortality of cirrhotic animals, to improve serum markers, and to restore liver mitochondrial function and detoxification. Morphological patterns of liver recovery were observed by histology. In comparison, an injection of fetal-specific factors produced similar functional recovery, whilst a more limited liver regeneration was observed by histology. CONCLUSIONS: The positive effects of fetal liver cell and cell-free fetal-specific factors in experimental cirrhosis may result from the presence of stage-specific factors activating hepatocellular repair.

Cryopreserved fetal liver cell transplants support the chronic failing liver in rats with CCl4-induced cirrhosis.

Hepatocyte transplantation is a promising method for supporting hepatic function in a broad spectrum of liver diseases. The aim of this work was to test the efficacy of human fetal liver cells to support the chronic failing liver in an experimental model of carbon tetrachloride (CCl4)-induced cirrhosis in rats. Liver cirrhosis was induced by intraperitoneal administration of CCl4 at a dose of 0.2 ml (50% v/v solution)/100 g body weight, twice a week for 3 months in rats. Ten days after stopping CCl4 administration (experimental day 0), rats received intrasplenic injection of cryopreserved fetal liver cells (FLC, 1 x 10(7) cells in 0.3 ml medium). As a cirrhotic control group, CCl4-induced cirrhotic rats were used with intrasplenic injection of an equal volume of medium alone. Animals were sacrificed on experimental day 15. Human fetal liver cell transplantation almost completely prevented the death of cirrhotic animals during the 2 weeks after treatment, while high ongoing mortality was seen in the cirrhotic control group. Cell transplantation into the spleen normalized total bilirubin and TBARSs levels and increased albumin levels in blood serum, as well as restoring mitochondrial function and liver detoxification function (assessed by cytochrome P450 contents and activity) compared with the activities seen in the cirrhosis control group. In parallel with this restoration of biochemical and functional liver indices, morphological patterns of liver recovery or regeneration after liver cell transplantation were demonstrated in day 15 samples by light microscopy. These were absent in the group that had received only medium alone.