Jean Claude Caritez

Trimetazidine prevents renal injury in the isolated perfused pig kidney exposed to prolonged cold ischemia.

BACKGROUND Ischemia caused by cold storage (CS) and reperfusion of the kidney is often responsible for delayed graft function after transplantation. Significant attention has been focused on the cascade of events involved in ischemia-reperfusion injury, with the objective of identifying drugs to ameliorate the functional damage that occurs. METHODS The purpose of this study was to evaluate the renal function of isolated perfused pig kidneys after 48 hr of CS with Euro-Collins (EC) solution plus trimetazidine (EC+TMZ), standard EC solution, or University of Wisconsin (UW) solution. Normothermic isolated perfused pig kidneys were randomized into five experimental groups: (A) control group (cold flush with cold heparinized saline and immediately reperfused; n=6); (B) cold flush with cold heparinized saline with TMZ (10(-6) M), n=6; (C) 48 hr of CS with EC and reperfusion (n=8); (D) 48 hr of CS with EC+TMZ alone and reperfusion (n=8); (E) 48 hr of CS with UW and reperfusion (n=8). Proton nuclear magnetic resonance spectroscopy and biochemical studies were performed for the functional evaluation during reperfusion. Lipid peroxidation was also determined. Histological examination (optical and electron microscopy) was performed after CS and reperfusion. RESULTS Using TMZ, the renal perfusate flow rate as well as the glomerular filtration rate and proximal tubular function were significantly improved. This improvement of renal function during reperfusion was correlated with a less significant cellular and interstitial edema. In addition, tubular injury markers were significantly lower in the group preserved with EC+TMZ, and TMZ reduced lipid peroxidation dramatically during reperfusion. CONCLUSIONS The addition of TMZ to the EC solution increased the preservation quality and renal tubular function, and gave protection from reperfusion injury better than EC alone or UW. These results strongly suggest that TMZ has a cytoprotective effect and may therefore be useful for kidney preservation.

Evaluation of Injury Preservation in Pig Kidney Cold Storage by Proton Nuclear Magnetic Resonance Spectroscopy of Urine

The isolated perfused kidney (IPK) model from pig was used to assess initial renal functions after cold flush and a 24- and 48-hour cold storage preservation (CSP) with Euro-Collins (EC) and to determine ischemia reperfusion (IR) impairment by biochemical, histological and proton nuclear magnetic resonance (NMR) spectroscopy of urine analysis. Eighteen pig kidneys were used. There were three experimental groups: Group 1--control kidneys flushed with cold heparinized saline, Group 2--cold flush followed by 24-hour CSP and reperfusion, Group 3--cold flush followed by 48-hour CSP and reperfusion. Kidneys were perfused for 2-hour at 37.5C for the determination of exogenous creatinine clearance (CCr), perfusion flow rate (PFR) and tubular function. Functional parameters and histological data are very poor after prolonged cold ischemia. Levels of tubular injury markers determined by proton NMR spectroscopy analysis were significantly higher with a longer ischemic time correlating well with the increased degree of renal functional and anatomic impairment. A new peak detected only in the 48-hour ischemic group was identified. In this model, proton NMR spectroscopy may be a useful technique in the evaluation of both new preservation solutions or methods.

Trimetazidine Reverses Deleterious Effects of Ischemia-Reperfusion in the Isolated Perfused Pig Kidney Model

Background: Delayed graft function has remained an important complication after renal transplantation. Methods: The purpose of this study was to evaluate Euro-Collins (EC) plus trimetazidine (TMZ) in comparison with standard EC solution after 24- or 48-hour cold storage. The normothermic isolated perfused pig kidney technique combined with proton nuclear magnetic spectroscopy was used. Results: The study verified that TMZ plus EC had a beneficial preservation effect over EC in terms of better perfusate flow rate at both 24 and 48 h (p < 0.01 and p < 0.001, respectively). In addition, TMZ also was beneficial in terms of increased glomerular filtration rate, better proximal tubular functions, and less tubular injury markers. Lipid peroxidation, evaluated by malondialdehyde renal tissue levels, was decreased in kidney homogenates preserved with TMZ, particularly after 48-hour cold storage. Citrate excretion which reflects a better intracellular pH regulation was detected in urine from kidneys preserved with TMZ. Histological data paralleled findings of the above when comparing cellular injury factors such as vacuolization, necrosis, tubular structure, and interstitial edema. Conclusion: These results indicate that, under the conditions of our experiments, the addition of TMZ to EC solution increased the preservation quality of kidneys particularly after prolonged cold ischemia.

Beneficial effects of a low-potassium+ and polyethylene glycol solution on renal function and structure during 48-hour cold storage preservation

Abstract ALTHOUGH the success of the first cold storage solution was attributed to its intracellular composition with low sodium and high potassium,1,2 the importance of impermeant agents has been shown and the potential deleterious effects of high potassium solutions have been suggested.3–5

Ischemia-reperfusion injury is associated with inflammatory cell infiltration: evaluation in a pig kidney autotransplant model.

DAMAGE sustained by the allograft during the process of transplantation has been shown to be influenced by cold ischemia-reperfusion injury, which is one of the principal “antigen-independent” factors. A previous study demonstrated that tissue injury occurs within isografts as compared to allografts, in the absence of alloantigen stimulation. In a rat model, a recent report suggests that molecules involved in T-cell costimulation may play a key role in ischemia-reperfusion in the kidney, independent of any alloimmune stimuli. The aim of this study was to assess the effect of the length of cold ischemic time in an autotransplant pig kidney model on delayed graft function and inflammatory cell infiltration.

Proton NMR spectroscopy as a novel approach to the monitoring of citrate and trimethylamine-N-oxide excretion after kidney preservation

Abstract HIGH resolution protin nuclear magnetic resonance (NMR) spectroscopy can be used for the rapid multicomponent analysis of low molecular weight metabolites in biologic fluids such as plasma and urine. Citrate (Cit) is an organic acid normally found in human urine. Reduced urinary Cit excretion has been described in HgCl 2 and p -aminophenol intoxication. 1 The mechanism is impairment of the Krebs cycle. Trimethylamine-N-oxide (TMAO) is an osmolyte molecule synthesized in the medullar cells of the kidney. 2 In plasma and urine, TMAO is not usually detected. Its excretion may be related to leakage from the renal medulla cells after intense medullar ischemia. The aim of this study was to assess Cit and TMAO excretion after prolonged cold storage (CS) with two standard solutions. These markers are precisely detected by proton NMR spectroscopy.

Beneficial effect on rat kidney preservation of the antiischemic agent trimetazidine during cold storage and reperfusion: Assessment by 31P nuclear magnetic resonance spectroscopy

Abstract IN RENAL transplantation, delayed graft function remains a major problem and increases the posttransplant morbidity and hospital costs. Trimetazidine (TMZ), an antiischemic drug, was introduced several years ago and used as an antianginal agent whose main effect is to be devoid of hemodynamic effects. TMZ is a cytoprotective drug that counteracts the metabolic disorders occurring at the level of ischemic cells. Several experimental results have suggested direct actions of the drug on mitochondrial function, intracellular acidosis, and calcium intracellular accumulation. 1,2 The aim of this study was to assess beneficial effect of TMZ during cold storage (CS) with Euro-Collins solution (EC) and normothermic reperfusion on energetic status of the kidneys.