Introduction- Oxidative stress in fatty livers enhances the risk of disease progression or organ dysfunction in surgery and transplantation. An experimental model of induced-NASH showed a liver metabolism subversion, reflected by tissue autofluorescence (AF) alterations. These consisted in changes in NAD(P)H/flavin AF related contributions -ascribable to redox metabolism alterationsand a rising in vitamin A, protein, and lipofuscin-like-lipopigment emission signals. Aim- Lipofuscin-like-lipopigments derive from the oxidation of unsaturated lipid. Therefore fluorescing fatty acids and oxidized products were investigated as early oxidative biomarkers in livers with mild lipid accumulation, under different preservation conditions. Materials and Methods- Rat livers(controls and 2 week administered methionine/choline-deficient diet-MCD) were isolated and submitted to 6-h Cold Storage (CS) or subnormotermic Machine Perfusion (MP), followed by reperfusion (37 oC, oxygenated medium). AF spectra recorded in vivo (exc 366 nm), via fiber-optic probe, were analyzed by curve fitting procedure, to estimate each endogenous fluorophore contribution to the overall emission, similarly to in situ biochemical analysis. Tissue oxidative stress (TBARS, and GSH) and mitochondrial dysfunction (ATP/ADP) were assayed using conventional methods. Results. Both CS or MP preservation affected liver AF properties. The response of NAD(P)H/flavin redox state to oxygenation and temperature was consistent with MCD induced mitochondrial dysfunction. Lipofuscin-like-lipopigment AF signals rose in both controls and MCD livers, in a good correlation with TBARS. Independent from preservation procedure, the phenomenon was significantly greater in MCD than in control livers, indicating a strong influence of fatty liver oxidative stress. Fluorescing fatty acids were not depleted, consistently with dynamic equilibria in liver lipid pool composition. Conclusions. The real time AF analysis allows to monitor oxidative effects even in a model of mild metabolic alterations, providing an AF support in experimental investigations on drug response and toxicity, and in the set-up of innovative organ preservation strategies.( Supported by Fondazione Cariplo, grant no2011-0439).
Autofluorescence detection of liver oxidative damage products
Croce A C;Bottiroli G;
2015
Abstract
Introduction- Oxidative stress in fatty livers enhances the risk of disease progression or organ dysfunction in surgery and transplantation. An experimental model of induced-NASH showed a liver metabolism subversion, reflected by tissue autofluorescence (AF) alterations. These consisted in changes in NAD(P)H/flavin AF related contributions -ascribable to redox metabolism alterationsand a rising in vitamin A, protein, and lipofuscin-like-lipopigment emission signals. Aim- Lipofuscin-like-lipopigments derive from the oxidation of unsaturated lipid. Therefore fluorescing fatty acids and oxidized products were investigated as early oxidative biomarkers in livers with mild lipid accumulation, under different preservation conditions. Materials and Methods- Rat livers(controls and 2 week administered methionine/choline-deficient diet-MCD) were isolated and submitted to 6-h Cold Storage (CS) or subnormotermic Machine Perfusion (MP), followed by reperfusion (37 oC, oxygenated medium). AF spectra recorded in vivo (exc 366 nm), via fiber-optic probe, were analyzed by curve fitting procedure, to estimate each endogenous fluorophore contribution to the overall emission, similarly to in situ biochemical analysis. Tissue oxidative stress (TBARS, and GSH) and mitochondrial dysfunction (ATP/ADP) were assayed using conventional methods. Results. Both CS or MP preservation affected liver AF properties. The response of NAD(P)H/flavin redox state to oxygenation and temperature was consistent with MCD induced mitochondrial dysfunction. Lipofuscin-like-lipopigment AF signals rose in both controls and MCD livers, in a good correlation with TBARS. Independent from preservation procedure, the phenomenon was significantly greater in MCD than in control livers, indicating a strong influence of fatty liver oxidative stress. Fluorescing fatty acids were not depleted, consistently with dynamic equilibria in liver lipid pool composition. Conclusions. The real time AF analysis allows to monitor oxidative effects even in a model of mild metabolic alterations, providing an AF support in experimental investigations on drug response and toxicity, and in the set-up of innovative organ preservation strategies.( Supported by Fondazione Cariplo, grant no2011-0439).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
