Lipid peroxidation in ischemia-reperfusion oxidative injury of the graft preserved in Celsior and University of Wisconsin solutions on a pig pancreas transplantation model

Ferroptosis: a cell death connecting oxidative stress, inflammation and cardiovascular diseases

Ferroptosis, a recently identified and iron-dependent cell death, differs from other cell death such as apoptosis, necroptosis, pyroptosis, and autophagy-dependent cell death. This form of cell death does not exhibit typical morphological and biochemical characteristics, including cell shrinkage, mitochondrial fragmentation, nuclear condensation. The dysfunction of lipid peroxide clearance, the presence of redox-active iron as well as oxidation of polyunsaturated fatty acid (PUFA)-containing phospholipids are three essential features of ferroptosis. Iron metabolism and lipid peroxidation signaling are increasingly recognized as central mediators of ferroptosis. Ferroptosis plays an important role in the regulation of oxidative stress and inflammatory responses. Accumulating evidence suggests that ferroptosis is implicated in a variety of cardiovascular diseases such as atherosclerosis, stroke, ischemia-reperfusion injury, and heart failure, indicating that targeting ferroptosis will present a novel therapeutic approach against cardiovascular diseases. Here, we provide an overview of the features, process, function, and mechanisms of ferroptosis, and its increasingly connected relevance to oxidative stress, inflammation, and cardiovascular diseases.

Potential benefits of melatonin in organ transplantation: a review

Organ transplantation is a useful therapeutic tool for patients with end-stage organ failure; however, graft rejection is a major obstacle in terms of a successful treatment. Rejection is usually a consequence of a complex immunological and nonimmunological antigen-independent cascade of events, including free radical-mediated ischemia-reperfusion injury (IRI). To reduce the frequency of this outcome, continuing improvements in the efficacy of antirejection drugs are a top priority to enhance the long-term survival of transplant recipients. Melatonin (N-acetyl-5-methoxytryptamine) is a powerful antioxidant and ant-inflammatory agent synthesized from the essential amino acid l-tryptophan; it is produced by the pineal gland as well as by many other organs including ovary, testes, bone marrow, gut, placenta, and liver. Melatonin has proven to be a potentially useful therapeutic tool in the reduction of graft rejection. Its benefits are based on its direct actions as a free radical scavenger as well as its indirect antioxidative actions in the stimulation of the cellular antioxidant defense system. Moreover, it has significant anti-inflammatory activity. Melatonin has been found to improve the beneficial effects of preservation fluids when they are enriched with the indoleamine. This article reviews the experimental evidence that melatonin is useful in reducing graft failure, especially in cardiac, bone, otolaryngology, ovarian, testicular, lung, pancreas, kidney, and liver transplantation.

Evaluation of Institut Georges Lopez-1 preservation solution in pig pancreas transplantation: a pilot study

BACKGROUND

Institut Georges Lopez-1 preservation solution (IGL-1) is an emerging extracellular-type electrolyte solution, low in viscosity, containing polyethylene glycol 35 as a colloid. Although IGL-1 has shown beneficial outcomes in kidney and liver preservation, this pilot study is the first to evaluate the efficacy of IGL-1 in pancreas transplantation (PT) compared with the University of Wisconsin solution (UW).

METHODS

Sixteen Landrace pigs underwent allogeneic PT with 16 hr of cold ischemia. Grafts were preserved with IGL-1 (n=8) or UW (n=8). No immunosuppression was administered. We analyzed graft function, the acute-phase response, and oxidative stress in the pancreatic graft monitoring membrane fluidity and lipid peroxidation.

RESULTS

All eight grafts with IGL-1, but only six with UW, were functioning. Graft failures with UW resulted from graft thrombosis. There were no differences between the two solutions in the number of normoglycemic days (IGL-1: 11.5 ± 6.2 versus UW: 8.5 ± 4.4 days, P=0.1357), nor in lipid peroxidation during 16-hr cold ischemia (P=0.672), or reperfusion (P=0.185), but IGL-1 prevented changes in membrane fluidity after reperfusion when compared with UW (P=0.026).

CONCLUSION

IGL-1 offered the same degree of safety and effectiveness as UW in our model of pig PT with 16 hr of cold ischemia.

Altered cellular membrane fluidity levels and lipid peroxidation during experimental pancreas transplantation

Although the pathogenesis of ischemia reperfusion (IR) injury is based on complex mechanisms, free radicals play a central role. We evaluated membrane fluidity and lipid peroxidation during pancreas transplantation (PT) performed in 12 pigs (six donors and six recipients). Fluidity was measured by fluorescence spectroscopy, and malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA) concentrations were used as an index of lipid oxidation. Pancreatic tissues were collected as follows: (A) donor, immediately before vascular clamping; (B) graft, following perfusion lavage with University of Wisconsin preservation fluid; (C) graft, after 16 h of cold ischemia; and (D) recipient, 30 min vascular postreperfusion. Fluidity and MDA and 4-HDA concentrations were similar in cases A, B, and C. However, there was significant membrane rigidity and increased lipid peroxidation after reperfusion (D). These findings suggest that reperfusion exaggerates oxidative damage and may account for the rigidity in the membranes of allografts during PT.

Melatonin prolongs graft survival of pancreas allotransplants in pigs

Oxidative stress is involved in ischemia-reperfusion injury and allograft rejection after transplantation. We studied two well-known antioxidants, melatonin and ascorbic acid (AA), in relation to the survival of a pancreas transplantation model without immunosuppression. Forty-eight Landrace pigs were divided into three groups (n = 16 each; eight donors and eight recipients) that received melatonin, AA, or no antioxidant therapy (controls). Melatonin and AA were administered (10 mg/kg body weight) intravenously to donors and recipients during surgery and on postoperative days 1-7. The molecules were also added (5 mm) to a University of Wisconsin preservation solution during organ cold storage. Melatonin significantly delayed acute rejection and prolonged allograft survival (25.1 ± 7.7 days) compared with the controls (8.1 ± 0.8 days, P = 0.013) and the AA group (9.4 ± 1.6 days, P = 0.049). Melatonin reduced indicators of oxidative stress, malondialdehyde, and 4-hydroxyalkenals, in pancreatic samples collected during procurement, cold ischemia, and reperfusion. Melatonin also reduced serum pig-major acute-phase protein/inter-α-trypsin inhibitor heavy chain 4 (pMAP/ITIH(4)) in the early post-transplantation period. AA only partially reduced oxidative damage 30 min postreperfusion and failed to prevent pMAP/ITIH(4) elevations. These findings suggested that melatonin may be a useful therapeutic tool for organ transplantation.

Effects of premedication with tiletamine/zolazepam/medetomidine during general anesthesia using sevoflurane/fentanyl in swine undergoing pancreas transplantation

OBJECTIVE

To assess cardiac and hemodynamic responses and body temperature during long-term general anesthesia using sevoflurane/fentanyl after premedication with a tiletamine/zolazepam/medetomidine combination in swine undergoing experimental pancreas transplantation.

MATERIALS AND METHODS

Twelve Landrace female pigs of means weight 46.4 +/- 5.1 kg were premedicated by intramuscular administration of tiletamine/zolazepam (3.5 mg/kg), medetomidine (0.03 mg/kg), and atropine (0.02 mg/kg), before anesthesia with 0.75 minimum alveolar concentration sevoflurane and continuous intravenous fentanyl infusion (5.7 +/- 0.7 microg/kg/h). Assessment of heart rate, arterial blood pressure, and temperature in pigs undergoing allogenic pancreas transplant surgery were registered at the start of anesthesia (T0), as well as at 60 (T60), 120 (T120), and 180 (T180) minutes after T0, and finally at the end of anesthesia (T anesthesia end), when we switched off the sevoflurane vaporizer. Analysis of variance was used to determine differences between times with P < .05 considered significant. Results are given as mean values +/- standard deviations.

RESULTS

Arterial blood pressure significantly decreased from T120 to the end of anesthesia, while a significantly decreased heart rate was only evident at T60. Body temperature decreased significantly from T60 to the end of anesthesia. These decreases, however, lacked clinical relevance; all parameters were within normal range. No major anesthetic complications were observed in this study.

CONCLUSIONS

The administration of a tiletamine/zolazepam/medetomidine combination as premedication in swine subjected to pancreas transplantation allowed for a safe reduction of sevoflurane/fentanyl requirements during long-term general anesthesia. Despite arterial blood pressure and body temperature evidencing a decrease during anesthetic maintenance, all parameters remained within normal range values.

Hypothermic organ preservation by static storage methods: Current status and a view to the future

The donor organ shortage is the largest problem in transplantation today and is one where organ preservation technology has an important role to play. Static storage of solid organs, especially of the kidney, continues to be the most common method employed for storage and transport of organs from deceased donors. However, the increase in organs obtained from expanded criteria donors and donors with cardiac death provide new challenges in crafting effective preservation methods for the future. This article reviews the current status of static hypothermic storage methods and discusses potential avenues for future exploitation of this technology as the available organ pool is expanded into the more marginal donor categories.

Pancreas preservation for pancreas and islet transplantation

PURPOSE OF REVIEW

To summarize advances and limitations in pancreas procurement and preservation for pancreas and islet transplantation, and review advances in islet protection and preservation.

RECENT FINDINGS

Pancreases procured after cardiac death, with in-situ regional organ cooling, have been successfully used for islet transplantation. Colloid-free Celsior and histidine-tryptophan-ketoglutarate preservation solutions are comparable to University of Wisconsin solution when used for cold storage before pancreas transplantation. Colloid-free preservation solutions are inferior to University of Wisconsin solution for pancreas preservation prior to islet isolation and transplantation. Clinical reports on pancreas transplants suggest that the two-layer method may not offer significant benefits over cold storage with the University of Wisconsin solution: improved oxygenation may depend on the graft size; benefits in experimental models may not translate to human organs. Improvements in islet yield and quality occurred from pancreases treated with inhibitors of stress-induced apoptosis during procurement, storage, isolation or culture desirable before islet isolation and transplantation and may improve islet yield and quality. Methods for real-time, noninvasive assessment of pancreas quality during preservation have been implemented and objective islet-potency assays have been developed and validated. These innovations should contribute to objective evaluation and establishment of improved pancreas-preservation and islet-isolation strategies.

SUMMARY

Cold storage may be adequate for preservation before pancreas transplants, but insufficient when pancreases are processed for islets or when expanded donors are used. Supplementation of cold-storage solutions with cytoprotective agents and perfusion may improve pancreas and islet transplant outcomes.

Effect of adenosine A2 receptor agonist on oxygen free radicals and apoptosis during ischemia reperfusion injury in rat pancreas

AIM: To investigate the role of adenosine A2 receptor agonist in protection from production of oxygeon free radicals and induction of apoptosis during ischemia and reperfusion injury in rat pancreas.

METHODS: The rats were divided randomly into sham, control and experimental groups. After 30 min clamping of subsplenic artery, normal saline (2 mL/kg body weight) or A2 receptor agonist CGS21680 (300 µg/kg body weight) was injected via dorsal penis vein, and at 15 min, 30 min and 60 min reperfusion, the changes of lipoperoxides (LPO), apoptosis and morphology in pancreas tissues were examined.

RESULTS: After 15, 30 and 60 min reperfusion, LPO increased significantly in control group compared with the sham operation group (8.25 ± 1.15 vs 1.63 ± 0.46, 10.67 ± 2.04 vs 1.85 ± 0.62, 15.31 ± 3.02 vs 2.02 ± 0.86, all P < 0.05) and experimental group (8.25 ± 1.15 vs 6.51 ± 1.38, 10.67 ± 2.04 vs 6.84 ± 1.74, 15.31 ± 3.02 vs 10.22 ± 2.91 µmol/L, all P < 0.05). Apoptosis increased significantly in control group compared with the sham operation group (0.55 ± 0.08 vs 0.18 ± 0.04, 1.21 ± 0.15 vs 0.20 ± 0.06, 2.63 ± 0.52 vs 0.23 ± 0.06, P < 0.05 or 0.01) and experimental group (0.55 ± 0.08 vs 0.32 ± 0.16 P < 0.05; 1.21 ± 0.15 vs 0.44 ± 0.20, 2.63 ± 0.52 vs 0.50 ± 0.43, all P < 0.05 or 0.01). In the control group, compared with 15 min reperfusion, LPO and apoptosis increased significantly at 30 min or 60 min reperfusion (P < 0.05 or 0.01). In sham operation group and experimental group, no remarked damage of pancreas was detected, but in control group, the pancreas damage became more serious with the prolonging of reperfusion.

CONCLUSION: Adenosine A2 receptor agonist attenuates postischemic production of oxygen free radicals and induction of apoptosis in pancreas tissues, thereby minimizes the ischemia reperfusion injury.

Pancreas preservation for pancreas and islet transplantation

PURPOSE OF REVIEW

To summarize advances and limitations in pancreas procurement and preservation for pancreas and islet transplantation, and review advances in islet protection and preservation.

RECENT FINDINGS

Pancreases procured after cardiac death, with in-situ regional organ cooling, have been successfully used for islet transplantation. Colloid-free Celsior and histidine-tryptophan-ketoglutarate preservation solutions are comparable to University of Wisconsin solution when used for cold storage before pancreas transplantation. Colloid-free preservation solutions are inferior to University of Wisconsin solution for pancreas preservation prior to islet isolation and transplantation. Clinical reports on pancreas and islet transplants suggest that the two-layer method may not offer significant benefits over cold storage with the University of Wisconsin solution: improved oxygenation may depend on the graft size; benefits in experimental models may not translate to human organs. Improvements in islet yield and quality occurred from pancreases treated with inhibitors of stress-induced apoptosis during procurement, storage, isolation or culture. Pancreas perfusion may be desirable before islet isolation and transplantation and may improve islet yields and quality. Methods for real-time, noninvasive assessment of pancreas quality during preservation have been implemented and objective islet potency assays have been developed and validated. These innovations should contribute to objective evaluation and establishment of improved pancreas preservation and islet isolation strategies.

SUMMARY

Cold storage may be adequate for preservation before pancreas transplants, but insufficient when pancreases are processed for islets or when expanded donors are used. Supplementation of cold storage solutions with cytoprotective agents and perfusion may improve pancreas and islet transplant outcomes.

[Solutions for organ preservation and other cardioplegic liquid formulations. Role of the hospital pharmacist]

Solid organ transplantation is an increasing need and a well-established activity which requires maintaining the quality of the transplant from procurement through the entire, storage, transport and graft procedure. Solutions for organ preservation play a key role in this procedure, by minimizing the deleterious effects of both ischemia and reperfusion. As such, their qualitative and quantitative compositions have to be optimized and validated. The development strategy and formulations proposed for these solutions are analyzed in this review as well as the results of the clinical studies which have set up the relevant pharmacological and physicochemical criteria. The French regulatory status of these products is also discussed. A clear distinction has to be made between solutions for organ preservation which are classified as produits thérapeutiques annexes (therapeutic ancillary products) and cardioplegic liquid formulations which are considered as medicinal products and are subject to marketing approval. Finally, the roles of the hospital pharmacist in the evaluation, selection, purchase and proper use of these products are described.