Biomedical subjects

Gaetano Serviddio

Publications and source records attributed to Gaetano Serviddio.

8 recordsLinked to original sources

PubMed2007

Mitochondrial function in liver disease.

Oxidative stress is involved in the pathogenesis and progression of different liver diseases, such as alcoholic liver disease and biliary cirrhosis. The increased mitochondrial production of O2(-) at complexes I and III, and consequently of H2O2 and other reactive oxygen species (ROS), triggered by NADH overproduction seems the major cause of mitochondrial and cellular oxidative stress and damage in chronic alcoholism. The mitochondrial oxidative stress renders hepatocytes susceptible to ethanol- or acetaldehyde-induced mitochondrial membrane permeability transition (MMPT) and apoptosis. Nitrosative stress contributes to cell death by peroxynitrite formation. The expression of the death receptor ligand CD95 is also up-regulated by acetaldehyde metabolism. Consequently, a dual mechanism, NADH-driven MMPT and CD95-mediated apoptosis, involving in both cases acetaldehyde metabolism and ROS production, operates in ethanol-induced apoptosis. In the biliary cirrhosis induced by chronic cholestasis, liver mitochondria show increased H2O2 production and GSH depletion and oxidation. Dysfunctional hepatocytes, with a loss in mitochondrial cardiolipin and decreased mitochondrial membrane potential evolve during cholestasis to apoptosis. Ursodeoxycholic acid prevents enlargement of this population as well as mitochondrial oxidative stress. Mitochondrial oxidative stress precedes the initiation and execution of hepatocyte apoptosis in chronic alcoholism and biliary cirrhosis. We suggest that overproduction of mitochondrial NADH is the primary cause for the development of alcoholic and non-alcoholic liver disease by a situation of chronic mitochondrial oxidative stress, which should be considered the second hit that renders hepatocytes susceptible to cell injury and apoptosis.

Animals↗

PubMed2006

Id2 leaves the chromatin of the E2F4-p130-controlled c-myc promoter during hepatocyte priming for liver regeneration.

The Id (inhibitor of DNA binding or inhibitor of differentiation) helix-loop-helix proteins are involved in the regulation of cell growth, differentiation and cancer. The fact that the molecular mechanisms of liver regeneration are not completely understood prompted us to study the fate of Id2 in proliferating liver. Id2 increases in liver regeneration after partial hepatectomy, following the early induction of its gene. Co-immunoprecipitation shows that Id2 forms a complex with E2F4, p130 and mSin3A in quiescent liver and all these components are present at the c-myc promoter as shown using ChIP (chromatin immunoprecipitation). Activation of c-myc during hepatocyte priming (G0-G1 transition) correlates with the dissociation of Id2 and HDAC (histone deacetylase), albeit p130 remains bound at least until 6 h. Moreover, as the G0-G1 transition progresses, Id2 and HDAC again bind the c-myc promoter concomitantly with the repression of this gene. The time course of c-myc binding to the Id2 promoter, as determined by ChIP assays is compatible with a role of the oncoprotein as a transcriptional inducer of Id2 in liver regeneration. Immunohistochemical analysis shows that Id2 also increases in proliferating hepatocytes after bile duct ligation. In this case, the pattern of Id2 presence in the c-myc promoter parallels that found in regenerating liver. Our results may suggest a control role for Id2 in hepatocyte priming, through a p130 dissociation-independent regulation of c-myc.

Animals↗

PubMed2005

Oxygen therapy at low flow causes oxidative stress in chronic obstructive pulmonary disease: Prevention by N-acetyl cysteine.

UNLABELLED: Exposure to high oxygen concentration produces toxicity by free radical release. We aimed to study: whether stable chronic obstructive pulmonary disease (COPD) patients present an unbalance in the blood redox status; the effect of oxygen administration on blood redox balance; the efficacy of N-acetyl-cysteine (NAC) treatment against the oxidative stress-induced by oxygen administration and whether it is dose-related. To this, 45 stable state III COPD patients were recruited and reduced glutathione (GSH) and oxidised glutathione (GSSG) in erythrocytes and thiol proteins (P-SH) and carbonyl proteins (PC) in both erythrocytes and plasma were evaluated. All COPD patients underwent 2 l/m oxygen for 18 h and NAC at 1200 or 1800 mg/day or placebo for 48 h starting with oxygen administration. Blood samples were collected at basal conditions, after 8 and 18 h of oxygen administration and 24 h after oxygen withdrawal. RESULTS: COPD patients present an unstable redox equilibrium mainly due to plasma sulphydryl protein depletion. Oxygen administration oxidize erythrocyte GSH, decrease P-SH and increase PC levels in both plasma and erythrocytes. NAC administration counteract the oxidative stress and at the highest dose completely prevent protein oxidation. In conclusion, stable state III COPD patients present an unstable redox balance; long term low flow oxygen administration induces systemic oxidative stress, which is prevented by NAC treatment.

Acetylcysteine↗

PubMed2005

Brief hypoxia before normoxic reperfusion (postconditioning) protects the heart against ischemia-reperfusion injury by preventing mitochondria peroxyde production and glutathione depletion.

Several recent works have shown that a brief ischemia applied during the onset of reperfusion (postconditioning) is cardioprotective in different animal models and that the early minutes of reperfusion are critical to its cardioprotection. This effect has been related to prevention of oxidative stress, but mechanisms have not been clearly demonstrated. The present study tested the hypothesis that mitochondria play a central role in peroxide production and oxidative stress during reperfusion and are responsible for the protective effect of postconditioning. Isolated perfused rat hearts were subjected to complete global ischemia for 45 min and reperfused for 40 min. Normoxic group was reperfused with a Krebs-Henseleit solution with the preischemic pO2 level (600 mmHg); in the "hypoxic group," normoxic reperfusion was preceded by 3 min with 150 mmHg pO2. Reperfusion was stopped at 3 and 40 min. The rate of hydroperoxide production, GSH, GSSG, and carbonyl protein levels were measured in mitochondria at 3 min and at the end of reperfusion. GSH and GSSG were also measured in tissue. Hemodinamic function was monitored during the experiment. LVEDp increased and LVDp decreased in the normoxic group but not in the hypoxic group. The rate of mitochondrial peroxide production was higher in normoxic than in the hypoxic group 3 min after reperfusion and at its conclusion. Accordingly, GSH was oxidized in normoxic but not in hypoxic hearts. Mitochondria carbonyl proteins were significantly higher in normoxic than in the hypoxic group at the end of reperfusion. In this model, 1) hypoxic reperfusion at the onset of reperfusion reduces myocardial injury; 2) the major rate of mitochondrial peroxide production is 3 min after the onset of reperfusion; 3) cardioprotection of postconditioning correlates with reduced mitochondria peroxide production and prevention of GSH oxidation.

Animals↗

PubMed2004

Exhaled Interleukine-6 and 8-isoprostane in chronic obstructive pulmonary disease: effect of carbocysteine lysine salt monohydrate (SCMC-Lys).

Chronic obstructive pulmonary disease (COPD) is characterized by an airways inflammation and by an enhanced generation of reactive oxygen species. The aim of our study was to assess the inflammation and the oxidative stress in airways of COPD patients with acute exacerbation of disease and in stability. Furthermore, we investigated the anti-inflammatory and antioxidant effects of 6 months treatment with carbocysteine lysine salt monohydrate (SCMC-Lys) in COPD. We studied 30 mild acute COPD, 10 mild stable COPD and 15 healthy subjects. 8-isoprostane and Interleukine-6 were measured in their breath condensate through immunoassay. Significantly higher concentrations of exhaled 8-isoprostane and Interleukine-6 were found in acute COPD patients compared to stable COPD and healthy controls (21.8+/-5.1 vs. 13.2+/-2.0 vs. 4.7+/-1.8 pg/ml and 7.4+/-0.9 vs. 5.8+/-0.2 vs. 2.7+/-0.6 pg/ml, p<0.0001). COPD patients treated with SCMC-Lys showed a marked reduction of exhaled 8-isoprostane and Interleukine-6 (8.9+/-1.5 and 4.6+/-0.8 pg/ml, p<0.0001). These findings suggest that there is an increase of 8-isoprostane and Interleukine-6 concentrations in the breath condensate of COPD patients compared to healthy controls especially during acute exacerbations of the disease. Moreover, we showed an anti-inflammatory and antioxidant effect of short-term administration of SCMC-Lys in COPD, suggesting the importance of a further placebo-controlled study that should evaluate the effects of this drug.

Adult↗

PubMed2004

RNAPol-ChIP: a novel application of chromatin immunoprecipitation to the analysis of real-time gene transcription.

We describe a procedure, RNAPol-ChIP, to measure actual transcriptional rate. It consists of the detection, by chromatin immunoprecipitation (ChIP), of RNA polymerase II within the coding region of genes. To do this, the DNA immunoprecipitated with polymerase antibodies is analysed by PCR, using an amplicon well within the coding region of the desired genes to avoid interferences with polymerase paused at the promoter. To validate RNAPol-ChIP, we compare our results to those obtained by classical methods in several genes induced during either liver regeneration or acute pancreatitis. When short half-life mRNA genes are studied (e.g. c-fos and egr1), RNAPol-ChIP gives results similar to those of other procedures. However, in genes whose mRNA is more stable (e.g. the hemopexin, hpx, gene) RNAPol-ChIP informs on real-time transcription with results comparable to those of methods such as nuclear run-on or run-off, which require the isolation of highly purified nuclei. Moreover, RNAPol-ChIP advantageously compares with methods based on the analysis of steady-state mRNA (northern blot or RT-PCR). Additional advantages of RNAPol-ChIP, such as the possibility of combining it with classical ChIP analysis to study transcription-associated changes in chromatin are discussed.

Acute Disease↗

PubMed2004

Ursodeoxycholic acid protects against secondary biliary cirrhosis in rats by preventing mitochondrial oxidative stress.

Ursodeoxycholic acid (UDCA) improves clinical and biochemical indices in primary biliary cirrhosis and prolongs survival free of liver transplantation. Recently, it was suggested that the cytoprotective mechanisms of UDCA may be mediated by protection against oxidative stress, which is involved in the development of cirrhosis induced by chronic cholestasis. The aims of the current study were 1) to identify the mechanisms involved in glutathione depletion, oxidative stress, and mitochondrial impairment during biliary cirrhosis induced by chronic cholestasis in rats; and 2) to determine the mechanisms associated with the protective effects of UDCA against secondary biliary cirrhosis. The findings of the current study indicate that UDCA partially prevents hepatic and mitochondrial glutathione depletion and oxidation resulting from chronic cholestasis. Impairment of biliary excretion was accompanied by decreased steady-state hepatic levels of gamma-glutamyl cysteine synthetase and gamma-cystathionase messenger RNAs. UDCA treatment led to up-regulation of gamma-glutamyl cysteine synthetase in animals with secondary biliary cirrhosis and prevented the marked increases in mitochondrial peroxide production and hydroxynonenal-protein adduct production that are observed during chronic cholestasis. A population of damaged and primarily apoptotic hepatocytes characterized by dramatic decreases in mitochondrial cardiolipin levels and membrane potential as well as phosphatidylserine exposure evolves in secondary biliary cirrhosis. UDCA treatment prevents the growth of this population along with the decreases in mitochondrial cardiolipin levels and membrane potential that are induced by chronic cholestasis. In conclusion, UDCA treatment enhances the antioxidant defense mediated by glutathione; in doing so, this treatment prevents cardiolipin depletion and cell injury in animals with secondary biliary cirrhosis.

Animals↗

PubMed2004

4-Hydroxynonenal is markedly higher in patients on a standard long-term home parenteral nutrition.

Parenteral nutrition, a commonly used procedure in patients with gastrointestinal disorders, may lead with time to liver steatosis and fibrosis, whose pathogenesis has yet to be elucidated. Oxidative stress and particularly lipid peroxidation likely contribute to the expression of such hepatobiliary complications, by means of their recognized proinflammatory and profibrogenic effects. To evaluate the adequacy against oxidative insult of a standard micronutrient supplementation in patients under long term parenteral nutrition, a comprehensive patterns of redox indices has been determined on peripheral blood samples from forty one adults in comparison to fifty eight blood donors taken as controls. A sustained oxidative stress in peripheral blood of home parenteral patients was observed. Of the two lipid peroxidation markers found to be markedly increased, namely fluorescent plasma protein adducts with malondialdehyde and 4-hydroxynonenal, respectively, only the second was statistically correlated with all the antioxidant-related changes consistently detected in the patients, namely decreased plasma alpha-tocopherol and selenium intake and higher erythrocyte oxidized glutathione. Plasma level of 4-hydroxynonenal-protein adducts appears to be a reliable and easily measurable marker of oxidative status, particularly indicated to monitor the adequacy of dietary regimen during parenteral nutrition.

Adult↗