Evidence for protective roles of polyethylene glycol plus high sodium solution and trimetazidine against consequences of renal medulla ischaemia during cold preservation and reperfusion in a pig kidney model

Effect of PERLA®, a new cold-storage solution, on oxidative stress injury and early graft function in rat kidney transplantation model

BACKGROUND

The composition of organ preservation solutions is crucial for maintaining graft integrity and early graft function after transplantation. The aim of this study is to compare new organ preservation solution PERLA® with the gold standard preservation solution University of Wisconsin (UW) regarding oxidative stress and early graft injury.

METHODS

In order to assess oxidative stress after cold storage, kidney grafts have been preserved for 18 h at 4° C in either UW solution or PERLA® solution and then assessed for oxidative stress injury (protocol 1). To assess kidney injuries and oxidative stress after reperfusion, rat kidneys were harvested, stored in cold UW or in PERLA® solutions for 18 h at 4 °C and then transplanted heterotopically for 6 h (protocol 2). PERLA® is a high Na+/low K+ solution including PEG-35 (1 g/L), trimetazidine (1 µM), carvedilol (10 µM) and tacrolimus (5 µM).

RESULTS

Our results showed that preservation of kidneys in PERLA® solution significantly attenuates oxidative stress parameters after cold storage and reperfusion. We found a significant decrease in oxidative damage indicators (MDA, CD and CP) and a significant increase in antioxidant indicators (GPx, GSH, CAT, SOD and PSH). Moreover, PERLA® solution decreased kidney injury after reperfusion (creatinine, LDH and uric acid).

CONCLUSION

PERLA® solution was more effective than UW storage solution in preserving rat's kidney grafts.

Effect of preservation solutions for static cold storage on kidney transplantation outcomes: A National Registry Study

This study aimed to evaluate how 5 preservation solutions for static cold storage affected kidney transplant outcomes. It included all first single kidney transplants during 2010-2014 from donations after brain death in the French national transplant registry, excluding preemptive transplants and transplants of kidneys preserved with a hypothermic perfusion machine. The effects of each preservation solution on delayed graft function (DGF) and 1-year transplant failure were evaluated with hierarchical multivariable logistic regression models. The study finally included 7640 transplanted kidneys: 3473 (45.5%) preserved with Institut Georges Lopez-1 solution (IGL-1), 773 (10.1%) with University of Wisconsin solution, 731 (9.6%) with Solution de Conservation des Organes et Tissus (SCOT, organ and tissue preservation solution), 2215 (29.0%) with Celsior, and 448 (5.9%) with histidine-tryptophan-ketoglutarate. Primary nonfunction rates did not differ by solution. After adjustment for donor, recipient, and transplant characteristics, the DGF risk was significantly lower with IGL-1 than with all other solutions (odds ratio [OR] 0.55, 95% confidence interval [CI] 0.48-0.64). Conversely, SCOT was associated with a DGF risk significantly higher than the other solutions (OR 2.69, 95% CI 2.21-3.27) and triple that of IGL-1 (OR 3.37, 95% CI 2.72-4.16). One year after transplantation, the transplant failure rate did not differ significantly by preservation solution. The difference between the groups for 1-year mean creatinine clearance was not clinically relevant.

Early Urinary Metabolomics in Patent Ductus Arteriosus Anticipates the Fate: Preliminary Data

Introduction: In premature neonates, the persistence of hemodynamically significant ductus arteriosus (hsPDA) can be associated with short- and long-term consequences, impairing their outcome. The correct strategy of management for such condition is under debate, especially regarding contraindications and/or side effects. In recent years, metabolomics was applied to several perinatal, pediatric, and adult conditions to investigate potential biomarkers of disease, which have become useful for early diagnosis and/or therapeutic management. Aim of the Study: The main purpose of our exploratory study was to asses, through ¹H-NMR metabolomics analysis of urinary samples at birth, possible metabolic pathways differentiating, with a significant predictive power, those preterm neonates who will subsequently develop hsPDA and neonates of comparable gestational age (GA) who will undergo spontaneous ductal closure or the persistence of an irrelevant PDA (no-hsPDA). Moreover, we investigated potential prenatal or perinatal clinical factors potentially influencing the development of hsPDA. Materials and Methods: We enrolled n = 35 preterm neonates with GA between 24 and 32 weeks; urinary samples were collected within the first 12 h of life. Patients were closely monitored regarding intensive care, respiratory support, fluid balance and administered drugs; an echocardiogram was performed at 48-72 h. Results: Our results reported a significant correlation between lower GA at birth and the development of hsPDA. Moreover, neonates with GA ≤ 30w developing hsPDA were characterized by lower Apgar scores at 1' and 5', higher rates of perinatal asphyxia, higher need of delivery room resuscitation and subsequent surfactant administration. Interestingly, metabolomics analysis at birth detected a clear separation between the ¹H-NMR urinary spectra of subjects GA ≤ 30w not developing hsPDA (n = 19) and those of subjects born at GA ≤ 30w in which hsPDA was confirmed at 48-72 h of life (n = 5). Conclusions: This is the first study applying metabolomics to investigate the PDA condition. Although preliminary and conducted on a limited sample, our results reveal that metabolomics could be a promising tool in the early identification of hsPDA, potentially superior to the clinical or laboratory predictive tools explored to date and even to the clinical observations and correlations in our sample, through the detection of specific urinary metabolites.

[Toward a customized preservation for each kidney graft?]

The increased number of patients in waiting list for renal transplantation requires the establishment of recommendations regarding graft preservation techniques. The preservation method impacts graft function and survival particularly in case of extended criteria donors. Based on our experience, the aim of this review is to establish a decisional diagram to draw graft management to 5years in relation to donor type and graft quality. Novel biomarkers are necessary to evaluate graft quality. Nuclear magnetic resonance or transcriptomic analyses are promising. Thus, good quality organs will be preserved in static condition associated to hypothermia; while grafts from extended criteria donors need to be assessed early during dynamic perfusion through an evaluation of perfusion solution to discriminate: good organs, with acceptable risks without perfusion conditions modifications; tolerable risk grafts for which it will be recommended to use a supplementation of perfusion solution with oxygen or pharmacologic additives such as mitochondrion protectors or oxygen carriers; and elevated risks graft which will not be used. This diagram based on experimental data needs to be assessed in clinical trials but highlights the crucial role of kidney graft quality assessment for its management and placed dynamic perfusion preservation as the protocol of choice for extended criteria donors.

High-molecular-weight polyethylene glycol enhances hypothermic storage of feline kidney cells

Phosphate-buffered sucrose (PBSc) solution is effective for short-term hypothermic preservation of tissue during feline kidney transplantation. A high-molecular-weight polyethylene glycol (35,000 Da, PEG35) reportedly enhanced the protective effects against cold-induced tubular injuries in animal kidney transplantation models. We investigated the ability of PBSc solution containing PEG35 to preserve cultured feline kidney cells using in vitro WST-8 cell proliferation assays. PEG35 significantly improved cell viability during 24 hr of cold preservation. PBSc containing 20 g/l PEG35 achieved an effect almost equal to that of University of Wisconsin (UW) solution, the gold standard preservation solution used in human clinical kidney transplantation, for up to 24 hr of preservation. Our results suggest that PBSc containing PEG35 provides an excellent medium for graft cold storage during feline kidney transplantation.

Effect of polyethylene glycol-based preservation solutions on graft injury in experimental kidney transplantation

Background

New preservation solutions are emerging, of various ionic compositions and with hydroxyethyl starch replaced by polymers such as polyethylene glycols (PEGs), offering the potential for ‘immunocamouflage’. This experimental study investigated which of three clinically available preservation protocols offered the best graft protection, based on epithelial-to-mesenchymal transition (EMT) and fibrosis.

Methods

Kidneys were preserved for 24 h at 4 °C with University of Wisconsin solution (UW) as standard, compared with solutions containing either 1 g/l PEG 35 kDa (Institute Georges Lopez solution, IGL) or 30g/l PEG 20 kDa (solution de conservation des organes et des tissus, SCOT). Animals were followed for up to 3 months and development of EMT, tubular atrophy and fibrosis was evaluated in comparison with sham-operated animals.

Results

Functional recovery was better in the SCOT group compared with the other groups. Chronic fibrosis, EMT and inflammation were observed in the UW and IGL groups, but limited in the SCOT group. Levels of profibrosis markers such as transforming growth factor β1, plasminogen activator inhibitor 1 and connective tissue growth factor were increased in IGL and UW groups compared with the SCOT group. Hypoxia-inducible factor (HIF) 1α and 2α expression was increased at 3 months in grafts preserved in UW and IGL, but detected transiently on day 14 when SCOT was used. Expression of HIF-regulated genes vascular endothelial growth factor and erythropoietin was increased in UW and IGL groups.

Conclusion

The choice of colloid and ionic content is paramount in providing long-term protection against chronic graft injury after renal transplantation. Preservation solutions based on PEGs may optimize graft quality.

Effects of medium and hypothermic temperatures on preservation of isolated porcine testis cells

The effects of medium and hypothermic temperatures on testis cells were investigated to develop a strategy for their short-term preservation. Testes from 1-week-old piglets were enzymatically dissociated for cell isolation. In Experiment 1, testis cells were stored at either room (RT) or refrigeration (RG) temperature for 6 days in one of 13 different media. Live cell recovery was assayed daily using trypan blue exclusion. In Experiment 2, three media at RG were selected for immunocytochemical and in vitro culture studies. Live cell recovery was also assayed daily for 6 days using both trypan blue exclusion and a fluorochrome assay kit. For all media tested, significantly or numerically more live cells were maintained at RG than RT. On preservation Day 3 at RG (cell isolation day as Day 0), 20% FBS-Leibovitz resulted in the highest live cell recovery (89.5 + or - 1.7%) and DPBS in the lowest (60.3 + or - 1.9%). On Day 6 at RG, 20% FBS- Leibovitz also resulted in the best preservation efficiency with 80.9 + or - 1.8% of Day 0 live cells recovered. There was no difference in live cell recovery detected by the two viability assays. After preservation, the proportion of gonocytes did not change, whereas that of Sertoli and peritubular cells increased and decreased, respectively. After 6 days of hypothermic preservation, testis cells showed similar culture potential to fresh cells. These results show that testis cells can be preserved for 6 days under hypothermic conditions with a live cell recovery of more than 80% and after-storage viability of 88%.

Protection of cellular and mitochondrial functions against liver ischemia by N-benzyl-N'-(2-hydroxy-3,4-dimethoxybenzyl)-piperazine (BHDP), a sigma1 ligand

We investigated the antiischemic properties of a new compound N-benzyl-N'-(2-hydroxy-3,4-dimethoxybenzyl)-piperazine (BHDP), having high affinity and selectivity for the sigma(1) receptor, in two different models of ischemia. The first was an experimental model of rat liver normothermic ischemia-reperfusion. Rats were pretreated with different doses of BHDP (0.5, 2.5 or 10 mg/kg/day, or solvent alone) and subjected to 90 min normothermic ischemia followed by either 30 or 120 min reperfusion. The second model was a hypothermic model of ischemia in which livers were incubated for 24 h at 4 degrees C in a preservation solution in the absence or presence of increasing BHDP concentrations (0.5, 2.5 or 10 microg/ml). These different ischemic conditions induced huge alterations in hepatocyte functions (membrane leakage of alanine aminotransferase and aspartate aminotransferase, decreased metabolic capacities evaluated by the ability of the liver to transform lidocaine, alterations of mitochondrial functions characterized by a decrease in ATP synthesis and the appearance of histological damages). Pretreatment of rats with BHDP alleviated these deleterious ischemia-reperfusion effects in a dose-dependent manner at both the cellular and mitochondrial levels. The protection of mitochondrial functions was almost complete at a dosage of 10 mg/kg/day during normothermic ischemia and 10 microg/ml in the preservation liquid during hypothermic ischemia. In addition, BHDP significantly reduced the histological damage. These data demonstrate that BHDP protects liver against the deleterious effects of ischemia-reperfusion and suggest that sigma(1) receptors play an important role in the protective effect.

Polyethylene glycol enhances colonic barrier function and ameliorates experimental colitis in rats

OBJECTIVE

Polyethylene glycol (PEG) has been suggested to protect against pathogen colonization by improving colonic barrier function. We aimed to establish whether PEG 4000 affects colonic barrier function and the development of colitis induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS) in rats.

MATERIALS AND METHODS

PEG was included in the drinking water for a period of 48 h before intracolonic administration of TNBS.

RESULTS AND DISCUSSION

PEG increased colonic surface hydrophobicity and diminished luminal bacterial load. Moreover, PEG markedly reduced mucosal damage and inflammation induced by TNBS. This protection effect appeared to be independent of its laxative properties since the laxatives mannitol or senna extracts had no effect on TNBS colitis. Using everted colonic sacs, pretreatment with PEG produced a lasting reduction in epithelial permeability to mannitol and dextran-70 K that correlated with decreased surface hydrophobicity.

CONCLUSION

Our results suggest that the protective effect of PEG on TNBS colitis is associated with reinforcement of the epithelial barrier.