Influence on energy kinetics and histology of different preservation solutions seen during cold ischemia in the liver.
ABSTRACT Cold flush preservation prolongs tissue viability during ischemia. However, there is little understanding of the effects of various preservation fluids on events during this period. A study of cold ischemia in rat livers was undertaken to compare biochemical and histological changes over time, using three preservation solutions: University of Wisconsin (UW), histidine-tryptophan-ketoglutarate (HTK), and Leeds solution (LS) under development at our institution. Leeds solution is a phosphate-based sucrose solution that like UW contains the impermeant lactobionate and the metabolite allopurinol (1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one) which acts as a competitive inhibitor of xanthine oxidase, stopping the breakdown of hypoxanthine to xanthine by oxidizing it to alloxanthine, inhibiting both the conversion of hypoxanthine to xanthine and the conversion of xanthine to uric acid.
At various time points, samples were analyzed for adenosine triphospate (ATP) and metabolites by high-performance liquid chromatography as well as for histological changes.
In all livers, ATP, ADP, and AMP degraded over 4 hours. In UW and LS groups, degradation beyond hypoxanthine was halted, and it continued in the HTK group. This blockade led to a significant reduction in the accumulation of xanthine and uric acid. Histological analysis showed protected architecture and maintenance of reticulin scaffolds in the UW and LS groups, whereas tissue breakdown was seen from earlier time points in the HTK group. Additionally, throughout ischemia, signs of pathological injury were more pronounced with UW- than with LS-preserved tissue.
These results implied that cold ischemia in the liver is characterized by dynamic biochemical changes coincident with pathological injury which are initiated from the time of organ perfusion and influenced by the choice of the perfusion fluid. Allopurinol in UW and LS appears to be critical. We hypothesized that it may also affect the degree of subsequent reperfusion injury. The data supported the assertion that LS offerred improved preservation over UW, adding to the impetus to shorten ischemic times in clinical transplantation.
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ABSTRACT: BACKGROUND: Literature is controversial whether organs from living donors have a better graft function than brain dead (BD) and non-heart-beating donor organs. Success of transplantation has been correlated with high-energy phosphate (HEP) contents of the graft. METHODS: HEP contents in heart, liver, kidney, and pancreas from living, BD, and donation after cardiac death in a pig model (n=6 per donor type) were evaluated systematically. BD was induced under general anesthesia by inflating a balloon in the epidural space. Ten hours after confirmation, organs were retrieved. Cardiac arrest was induced by 9V direct current. After 10min of ventricular fibrillation without cardiac output, mechanical and medical reanimation was performed for 30min before organ retrieval. In living donors, organs were explanted immediately. Freeze-clamped biopsies were taken before perfusion with Celsior solution (heart) or University of Wisconsin solution (abdominal organs) in BD and living donors or with Histidine-Tryptophan-Ketoglutaric solution (all organs) in non-heart-beating donors, after perfusion, and after cold ischemia (4h for heart, 6h for liver and pancreas, and 12h for kidney). HEPs (adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, and phosphocreatine), xanthine, and hypoxanthine were measured by high-performance liquid chromatography. Energy charge and adenosine triphosphate-to-adenosine diphosphate ratio were calculated. RESULTS: After ischemia, organs from different donor types showed no difference in energy status. In all organs, a decrease of HEP and an increase in hypoxanthine contents were observed during perfusion and ischemia, irrespective of the donor type. CONCLUSION: Organs from BD or non-heart-beating donors do not differ from living donor organs in their energy status after average tolerable ischemia.Journal of Surgical Research 05/2012; · 2.02 Impact Factor
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ABSTRACT: Introduction The solution in which graft tissue is stored (that is, preservation solution) is an important component of liver transplantation technology. Its protective effect is induced by substances in the solution, including radical scavengers, buffers, and energy-giving substances. New preservation solutions have proven to be effective in preventing organ damage during cold ischemia and in extending the time limits for storage. Aim This study determined the relationship between luminescence intensity and content of adenosine triphosphate (ATP) in liver tissue and proposes a new ex vivo screening system that uses Lewis rats transgenic for luciferase for evaluating the effectiveness of preservation solutions. Methods Samples (diameter, 2 mm) of liver were obtained from transgenic rats. The viability of these tissues after storage for as long as 6 hours in University of Wisconsin (UW) solution, extracellular trehalose solution of Kyoto, Euro-Collins (EC) solution, histidine–tryptophan–ketoflutarate solution, low potassium dextran solution, or normal saline was assessed by determining ATP content and luminescence intensity. Results Luminescence had a linear relationship (R = 0.88) with ATP levels. Regardless of the preservation solution used, the luminescence intensities of the liver tissue chips decreased linearly with time especially through a short span of time (0 to 2 hours; R2 = 0.58–1.0). The luminescence of liver chip tissues maintained long term (2 to 6 hours) in UW solution tended to be higher than those of tissues stored in other solutions (P < .05; 6 hours). On the basis of luminescence intensity, EC might be preferable to the other solutions tested for ultra-short–term storage (0.5 to 2 hours). Conclusion Our model, which combines the use of the bioimaging system and Lewis rats transgenic for luciferase, effectively assessed the viability of liver tissue samples. We believe that this ex vivo screening system will be an effective tool for evaluating preservation solutions for liver grafts.Transplantation Proceedings 01/2014; 46(1):63–65. · 0.95 Impact Factor
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ABSTRACT: In order to gain further insight into the mechanisms of tissue damage during the progression of liver diseases as well as the liver preservation for transplantation, an improved understanding of the relation between the mechanical and histological properties of liver is necessary. We suggest that this relation can only be established truly if the changes in the states of those properties are investigated dynamically as a function of post mortem time. In this regard, we first perform mechanical characterization experiments on three bovine livers to investigate the changes in gross mechanical properties (stiffness, viscosity, and fracture toughness) for the preservation periods of 5, 11, 17, 29, 41 and 53h after harvesting. Then, the histological examination is performed on the samples taken from the same livers to investigate the changes in apoptotic cell count, collagen accumulation, sinusoidal dilatation, and glycogen deposition as a function of the same preservation periods. Finally, the correlation between the mechanical and histological properties is investigated via the Spearman's Rank-Order Correlation method. The results of our study show that stiffness, viscosity, and fracture toughness of bovine liver increase as the preservation period is increased. These macroscopic changes are very strongly correlated with the increase in collagen accumulation and decrease in deposited glycogen level at the microscopic level. Also, we observe that the largest changes in mechanical and histological properties occur after the first 11-17h of preservation.Journal of the Mechanical Behavior of Biomedical Materials 01/2014; 29:403-416. · 2.37 Impact Factor