Amiodarone pretreatment of organ donors exerts anti-oxidative protection but induces excretory dysfunction in liver preservation and reperfusion

Use of an antiarrhythmic drug against acute selenium toxicity

OBJECTIVE

Selenium is an essential trace element. But, selenium may have toxic effects in high doses. There are no proven antidotes or curative treatments for acut selenium toxicity. Treatment involves stopping the exposure and providing supportive care for symptoms. Therefore, it is necessary to find more effective substances in the treatment of selenium toxicity. The aim of this study was to increase the survival rate of animals by supporting the heart with amiodarone and to determine the effect of amiodarone on the pathological, hematological and biochemical parameters in acute selenium intoxication.

METHODS

64 Wistar-Albino rats were divided into four groups. Group I was given only distilled water, Group II was given 18 mg/kg dose of amiodarone, Group III was given 18 mg/kg amiodarone and 10 mg/kg sodium selenite and Group IV was given sodium selenite 10 mg/kg (LD₅₀ dose)orally.

RESULTS

11 of the 16 animals in Group IV died within the first 48 h of drug administration. However, no deaths were observed in the rats in Group III. No hematological changes were observed. Biochemically, CK, CK-MB and LDH levels of Group IV were higher than the other groups on both the 2nd and 10th days. In Groups II and III, this serum level decreased, and vitamin B12 levels increased. In macroscopic inspections of the organs of Groups III and IV, slight paleness was detected. Histopathologically, degenerative changes in tissue were observed, especially in Group IV.

CONCLUSION

This study shows that amiodarone application has a reducing effect on selenium toxicity. This was because amiodarone protected the heart by reducing CK and CK-MB levels and increased vitamin B12 levels, which play a role in the synthesis of S-adenosyl methionine that converts selenium into a nontoxic form.

Evidence for tumor cell spread during local hepatic ablation of colorectal liver metastases

INTRODUCTION

The aim of the present study was to analyze the impact of cryosurgery (CRYO) on liver metastases compared to other thermoablative techniques. In a rat liver metastases model, evidence for tumor cell spread was analyzed comparing CRYO, radiofrequency ablation (RFA), and laser-induced thermotherapy (LITT).

METHODS

In an experimental study, we compared cell spillage in the washout of isolated perfused rat livers undergoing thermal ablation. Within the same model, CC531-GFP rat liver tumors were treated with CRYO, RFA, or LITT and the number of vital tumor cells within the perfusate was measured. Matrix metalloproteinases (MMP-2, MMP-9) were analyzed after in vivo ablation of rat colorectal liver metastases in the third experimental model.

RESULTS

Our data showed pronounced washout of cells after CRYO with a higher amount of intravascular cells and cell detritus compared to RFA and LITT. Only the effluent fluid of cryosurgery-treated livers revealed GFP-stained tumor cells. MMP-2 and MMP-9 expression was significantly higher after cryosurgery than after RFA and LITT.

CONCLUSION

When using thermoablative techniques, intravascular metastatic cell spillage is highest in CRYO, and increased expression of matrix metalloproteinases may further facilitate tumor cell spread. Therefore, RFA and LITT may be preferable whenever surgical resection of liver tumors is impossible.

Multidrug donor preconditioning protects steatotic liver grafts against ischemia-reperfusion injury

BACKGROUND

Graft dysfunction of steatotic livers (SL) still remains a major challenge in liver transplantation. Different mechanisms are thought to be involved in the impaired tolerance of SL to ischemia-reperfusion injury. Thus, different pharmacologic strategies may need to be combined to effectively protect SL and to reduce graft dysfunction after transplantation. Therefore, we analyzed the effectiveness of a multidrug donor preconditioning (MDDP) procedure to protect SL from cold ischemia-reperfusion injury.

METHODS

Liver steatosis was induced by a high-carbohydrate, fat-free diet. A total of 24 Sprague-Dawley rats were divided into 3 groups (n = 8 each), including a control group with nonsteatotic livers (Con), a vehicle-treated SL group (SL-Con), and a SL group undergoing MDDP (SL-MDDP), including pentoxyphylline, glycine, deferoxamine, N-acetylcysteine, erythropoietin, melatonin, and simvastatin. MDDP was applied before liver perfusion with 4°C histidine-tryptophan-ketoglutarate (HTK) solution and organ harvest. After 24 hours of cold storage in HTK, postischemic reperfusion was performed in an isolated liver reperfusion model using 37°C Krebs-Henseleit bicarbonate buffer.

RESULTS

After 60 minutes of reperfusion, SL showed a significant reduction of bile flow as well as a marked increase of liver enzyme levels and apoptotic cell death compared with Con. This was associated with an increased malondialdehyde formation, interleukin-1 production, and leukocytic tissue infiltration. MDDP completely abolished the inflammatory response and was capable of significantly reducing parenchymal dysfunction and injury.

CONCLUSIONS

MDDP decreases SL injury after cold storage and reperfusion. The concept of MDDP as a simple and safe preoperative regime, thus may be of interest in clinical use, expanding the donor pool from marginal donors.

Donor pretreatment with tetrahydrobiopterin saves pancreatic isografts from ischemia reperfusion injury in a mouse model

Depletion of the nitric oxide synthase cofactor tetrahydrobiopterin (H4B) during ischemia and reperfusion is associated with severe graft pancreatitis. Since clinically feasible approaches to prevent ischemia reperfusion injury (IRI) by H4B-substitution are missing we investigated its therapeutic potential in a murine pancreas transplantation model using different treatment regimens. Grafts were subjected to 16 h cold ischemia time (CIT) and different treatment regimens: no treatment, 160 μM H4B to perfusion solution, H4B 50 mg/kg prior to reperfusion and H4B 50 mg/kg before recovery of organs. Nontransplanted animals served as controls. Recipient survival and endocrine graft function were assessed. Graft microcirculation was analyzed 2 h after reperfusion by intravital fluorescence microscopy. Parenchymal damage was assessed by histology and nitrotyrosine immunohistochemistry, H4B tissue levels by high pressure liquid chromatography (HPLC). Compared to nontransplanted controls prolonged CIT resulted in significant microcirculatory deterioration. Different efficacy according to route and timing of administration could be observed. Only donor pretreatment with H4B resulted in almost completely abrogated IRI-related damage showing graft microcirculation comparable to nontransplanted controls and restored intragraft H4B levels, resulting in significant reduction of parenchymal damage (p < 0.002) and improved survival and endocrine function (p = 0.0002 each). H4B donor pretreatment abrogates ischemia-induced parenchymal damage and represents a promising strategy to prevent IRI following pancreas transplantation.

Multidrug donor preconditioning prevents cold liver preservation and reperfusion injury

PURPOSE

Primary graft dysfunction still represents a major challenge in liver transplantation. We herein studied in an isolated rat liver perfusion model whether a multidrug donor preconditioning (MDDP) can not only reduce but also completely prevent cold ischemia-reperfusion injury.

METHODS

MDDP included curcumin, simvastatin, N-acetylcysteine, erythropoietin, pentoxyphylline, melatonin, glycine, and methylprednisolone. Postischemic reperfusion was performed after 24 h cold storage in histidine-tryptophan-ketoglutarate solution with 37°C Krebs Henseleit bicarbonate buffer.

RESULTS

Cold hepatic ischemia-reperfusion resulted in a massive K(+) release, protein loss, and aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase elevation. This was associated with increased malondialdehyde formation, enhanced tumor necrosis factor-alpha and interleukin-6 production, pronounced leukocytic tissue infiltration, and apoptotic cell death.

CONCLUSIONS

MDDP abolished the inflammation response and was capable of completely preventing the manifestation of parenchymal injury. Thus, MDDP potentiates the protective effects reported after single-drug donor preconditioning and may therefore be an interesting approach to improve the outcome in clinical liver transplantation.