Effect of Propofol, Sevoflurane and Desflurane on Systemic Redox Balance

We studied the effects of Propofol, Desflurane, and Sevoflurane on the systemic redox balance in patients undergoing laparohysterectomy. We measured blood concentration of glutathione (GSH), plasma antioxidant capacity (Trolox Equivalent Antioxidant Capacity-TEAC), and lipid peroxidation products (malondialdehyde (aMDA) and 4-hydroxynonenal (aHNE) protein adducts). Sixty patients were randomly placed into three groups of twenty people each. In Group P anesthesia was induced with Propofol 2 mg/kg and maintained with 12–10–8 mg/kg/min; in Groups S and D anesthesia was induced with 3 mg/kg Sodium Thiopental and maintained with 2% Sevoflurane and 6% Desflurane, respectively. Blood samples were collected prior to induction (T0bas), 60min and 24h postoperatively (T160' and T224 h). In Group P, GSH increased on T160' (p<0.02) and returned to baseline on T24h, while TEAC remained unmodified; in Groups S, GSH and TEAC decreased on T160' (p<0.01 vs. T0bas, p<0.03 vs. T0bas, respectively); in Group D, on T160' there was a slight decrease of GSH and TEAC. The levels of aMDA slightly decreased throughout the study periods in Group P, increased in Group D, and remained stable in Group S. Propofol showed antioxidant properties, while Sevoflurane and Desflurane seemed to shift the redox balance towards oxidation, yet without inducing overt oxidative damage.

Long-term results of sorafenib in advanced-stage hepatocellular carcinoma: what can we learn from routine clinical practice?

BACKGROUND AND AIMS

Prospective randomized trials have proven that sorafenib is a valid treatment option for patients with advanced-stage hepatocellular carcinoma (HCC). The aim of the present study is to evaluate the effectiveness and safety of sorafenib in patients encountered in routine clinical practice.

METHODS

From September 2008 to March 2011, 42 cirrhotic patients (30 male; 12 female; mean age: 70.2 ± 7.6 years; range: 56-85 years) with HCC of Barcelona Clinic Liver Cancer stage B (n = 5) or C (n = 37; mean size: 66.6 ± 42.3 mm; mean number per patient: 3.3 ± 2.8) were treated with sorafenib at either a standard dose of 800 mg/day (n = 29; 69.1%) or at 400 mg/day with subsequent dose escalation (ramp-up strategy; n = 13, 30.9%). Baseline clinical parameters were comparable. Clinical data and side effects, laboratory analyses (in particular, serum α-fetoprotein) and radiological data (tumor response according to amended RECIST criteria) were assessed every 3 months. Survival was calculated by Kaplan-Meier analysis.

RESULTS

Mean follow-up was 12.2 ± 9 months (range: 1-32 months). Median overall survival was 26.1 months with overall 6- and 12-month survival rates of 92.1 and 85%, respectively. Median time to radiological progression was 8 months. The progression-free rate was 64.3%. Fatigue, skin disorders and diarrhea were the most frequent grade 3-4 side effects. Treatment discontinuation occurred in 25 patients. The starting dose for the last 13 enrolled patients was 400 mg/day; in the absence of toxicity this dosage was gradually increased to 800 mg/day after 3 weeks ('ramp-up strategy'). No grade 3/4 adverse events were observed in the ramp-up group.

CONCLUSION

Sorafenib is a valid treatment option for advanced-stage HCC. Starting at a lower dosage may allow prolonged compliance to treatment and might be considered according to patient tolerance.

The impact of interferon lambda 3 gene polymorphism on natural course and treatment of hepatitis C

Host genetic factors may predict the outcome and treatment response in hepatitis C virus (HCV) infection. Very recently, three landmark genome-wide association studies identified single nucleotide polymorphisms near the interleukin 28B (IL28B) region which were more frequent in responders to treatment. IL28B encodes interferon (IFN)λ3, a type III IFN involved in host antiviral immunity. Favourable variants of the two most widely studied IL28B polymorphisms, rs12979860 and rs8099917, are strong pretreatment predictors of early viral clearance and sustained viral response in patients with genotype 1 HCV infection. Further investigations have implicated IL28B in the development of chronic HCV infection versus spontaneous resolution of acute infection and suggest that IL28B may be a key factor involved in host immunity against HCV. This paper presents an overview about the biological activity and clinical applications of IL28B, summarizing the available data on its impact on HCV infection. Moreover, the potential usefulness of IFNλ in the treatment and natural history of this disease is also discussed.

Mitochondrial oxidative stress and respiratory chain dysfunction account for liver toxicity during amiodarone but not dronedarone administration

The role played by oxidative stress in amiodarone-induced mitochondrial toxicity is debated. Dronedarone shows pharmacological properties similar to those of amiodarone but several differences in terms of toxicity. In this study, we analyzed the effects of the two drugs on liver mitochondrial function by administering an equivalent human dose to a rat model. Amiodarone increased mitochondrial H(2)O(2) synthesis, which in turn induced cardiolipin peroxidation. Moreover, amiodarone inhibited Complex I activity and uncoupled oxidative phosphorylation, leading to a reduction in the hepatic ATP content. We also observed a modification of membrane phospholipid composition after amiodarone administration. N-acetylcysteine completely prevented such effects. Although dronedarone shares with amiodarone the capacity to induce uncoupling of oxidative phosphorylation, it did not show any of the oxidative effects and did not impair mitochondrial bioenergetics. Our data provide important insights into the mechanism of mitochondrial toxicity induced by amiodarone. These results may greatly influence the clinical application and toxicity management of these two antiarrhythmic drugs.

Transarterial chemoembolization in very early and early-stage hepatocellular carcinoma patients excluded from curative treatment: a prospective cohort study

AIM

To assess clinical outcome of transarterial chemoembolization (TACE) in a series of patients with early-stage hepatocellular carcinoma (HCC), within Milan criteria, but clinically unfit for liver transplantation (OLT).

METHODS

From January 2006 to May 2009, 67 patients (43 males, mean age 70 ± 7.6 years) with very early or early-stage unresectable HCC, within Milan selection criteria but clinically unfit for OLT, underwent TACE. The primary endpoint of the study was overall survival. Secondary endpoints were: safety, liver toxicity, 1-month tumour response according to the amended RECIST criteria, time to local and distant intrahepatic tumour recurrence and time to radiological progression.

RESULTS

Two major periprocedural complications occurred (3%), consisting of liver failure. Periprocedural mortality rate was 1.5% (1 patient). A significant increase in ALT and bilirubin levels 24h after treatment was reported, with progressive decrease at discharge. At 1-month follow-up, complete and partial tumour response rates were 67.2% and 29.8%, respectively, with two cases of progressive disease. Mean follow-up was 37.3 ± 15 months. The 1-, 2-, and 3-year overall survival rates were 90.9%, 86.1%, and 80.5%, respectively. Median expected time to local tumour recurrence and intrahepatic tumour recurrence were 7.9 and 13.8 months, respectively. Radiological disease progression was observed in 12 patients (17.9%) with a mean expected time of 26.5 months.

CONCLUSION

In patients with early-stage HCC, clinically excluded from OLT and unfit for surgery or percutaneous ablation, TACE is a safe and effective option, with favourable long-term survival.

Mitochondrial dysfunction in nonalcoholic steatohepatitis

The pathogenesis of nonalcoholic steatohepatitis (NASH) is poorly understood and the mechanisms are still being elucidated. Mitochondrial dysfunction participates at different levels in NASH pathogenesis since it impairs fatty liver homeostasis and induces overproduction of free radicals that in turn trigger lipid peroxidation and cell death. In this article, we review the role of mitochondria in fat metabolism, energy homeostasis and reactive oxygen species production, with a focus on the role of mitochondrial impairment and uncoupling proteins in the pathophysiology of NASH progression. The potential effects of some molecules targeted to mitochondria are also discussed.

Complete response for advanced liver cancer during sorafenib therapy: case report

Background

Hepatocellular carcinoma (HCC) is the fifth most common neoplasia in the world. In the past, treatment of advanced HCC with conventional antineoplastic drugs did not result in satisfactory outcomes: recently, in this patient population the oral multikinase inhibitor sorafenib has been able to induce a statistically significant improvement of overall survival. Similarly to other anti-angiogenic drugs employed in other tumour types, also sorafenib seldom induces the dimensional tumour shrinking usually observed with conventional cytotoxic drugs: data gathered from studies carried out with sorafenib and other competitors under development do not report any complete response in HCV-induced HCC.

Case presentation

An 84-year old man with a long-lasting history of chronic HCV hepatitis was referred to our Institution for an ultrasonography investigation of a focal hepatic lesion. To better characterize the liver disease and clearly define the diagnosis of the focal hepatic lesion, the patient was hospitalized in our department. Laboratory and instrumental investigations confirmed the clinical picture of HCV-related liver cirrhosis and identified a hepatic lesion of about 6 cm featuring infiltrating HCC with thrombosis of the portal trunk. Due to the advanced stage of the disease, therapy with sorafenib 400 mg bid was started. Right from one month after the treatment was started, a reduction of alpha-fetoprotein level was observed which, by the third month, turned down within the normal limits. In addition the CT scan showed 50% reduction of the neoplastic lesion along with canalization of the portal trunk. At the sixth month the normalization of the alpha-fetoprotein level at the lower limit of normality was confirmed and the MRI showed complete disappearance of the neoplasia. In addition a reduction of a metallo-proteinase serum level was obserdved. At the twelfth month a further MRI confirmed complete response had been maintained. At present the patient is in a follow-up program to evaluate the duration of the complete response.

Conclusions

This case is worth mentioning since, to the best of our knowledge, it represents the first evidence of complete response to sorafenib in an elderly patient with advanced HCV-related HCC.

Oxidation of hepatic carnitine palmitoyl transferase-I (CPT-I) impairs fatty acid beta-oxidation in rats fed a methionine-choline deficient diet

There is growing evidence that mitochondrial dysfunction, and more specifically fatty acid β-oxidation impairment, is involved in the pathophysiology of non-alcoholic steatohepatitis (NASH). The goal of the present study was to achieve more understanding on the modification/s of carnitinepalmitoyltransferase-I (CPT-I), the rate-limiting enzyme of the mitochondrial fatty acid β-oxidation, during steatohepatitis. A high fat/methionine-choline deficient (MCD) diet, administered for 4 weeks, was used to induce NASH in rats.We demonstrated that CPT-I activity decreased, to the same extent, both in isolated liver mitochondria and in digitonin-permeabilized hepatocytes from MCD-diet fed rats.At the same time, the rate of total fatty acid oxidation to CO(2) and ketone bodies, measured in isolated hepatocytes, was significantly lowered in treated animals when compared to controls. Finally, an increase in CPT-I mRNA abundance and protein content, together with a high level of CPT-I protein oxidation was observed in treated rats. A posttranslational modification of rat CPT-I during steatohepatitis has been here discussed.

Principles and therapeutic relevance for targeting mitochondria in aging and neurodegenerative diseases

Aging is a physiologic state in which a progressive decline of organ functions may be accompanied by developing age-related diseases and neurodegenerative diseases. The causes of such conditions remain unknown, being probably related to a multifactor process. To date, the Free Radical and Mitochondrial theories seem to be the two most prominent that could explain both how and why aged people develop certain disorders, providing a rationale for treatment. Several reports demonstrate that mitochondria play a key role in aging and some neurodegenerative diseases. Damaged mitochondria produce increased amounts of Reactive Oxygen Species (ROS), leading, in turn, to progressive augmentation in damage. Dysfunctional mitochondria enhance susceptibility to cell death. Indeed, at cell level mitochondria act as an energetic hub determining cell final fate through caspase-dependent apoptosis. Thus, if aging results from oxidative stress, it may be corrected by environmental, nutritional and pharmacological strategies. In this review we summarize the role of mitochondria dysfunction occurring in aging and neurodegenerative disease, describing novel mitochondria-targeted therapy approach and the new selective molecules and nanocarriers technology as potentially effective in targeting mitochondrial dysfunction.

Feasibility and safety of granulocytapheresis in Crohn's disease: a prospective cohort study

BACKGROUND AND OBJECTIVE

This study evaluated the feasibility and safety of granulocytapheresis (GCAP) in inducing and maintaining remission in refractory Crohn's disease. The relationship between the clinical outcomes and the location (ileal or ileocolonic) of disease was also assessed.

PATIENTS

We evaluated 16 patients with ileal location (group A), 14 with ileocolonic location (group B). The patients underwent five sessions (1 session/wk) of GCAP (Adacolumn(TM)). CDAI was measured at the end of the GCAP, at 6, 9 and 12 months.

RESULTS AND CONCLUSIONS

No major complications were observed. At the end of GCAP, 19 (63.3%) patients showed a clinical remission: 10 (62.5%) in group A versus 9 (64.2%) in group B. At 6 months, 16 (53.3%) of the cases had maintained remission: 9 (56.2%) in group A versus 7 (50.0%) in group B. At 9 months, 13 (43.3%) patients had maintained remission: 7 (43.7%) in group A versus 6 (42.8%) in group B. At 12 months, 12 (40%) patients were still in clinical remission: 7 (43.7%) in group A versus 5 (35.7%) in group B. Risk of relapse was not related to disease location. The procedure was well tolerated and feasible in an important percentage of Crohn's disease patients.

Quantitative determination of hepatitis C core antigen in therapy monitoring for chronic hepatitis C

The correlation and kinetics of hepatitis C virus (HCV) RNA and HCV core antigen levels in chronic hepatitis C patients treated with pegylated interferon + ribavirin were evaluated in order to envision a combined use of the two assays in therapy monitoring. HCV core antigen levels by a chemiluminescent immunoassay (Abbott ARCHITECT) and HCV-RNA levels by branched DNA (bDNA) or real-time PCR have been evaluated on plasma specimens from 32 patients treated for chronic hepatitis C. An early virological response (undetectable levels of HCV-RNA 4 weeks after start of treatment) was found in 10/23 subjects (43.5%) followed up for 5 months or more. The response was linked to the HCV genotype (20% in genotype 1B vs. 61.5% in other genotypes; p < 0.05). HCV RNA and HCV antigen showed a good correlation (r = 0.814); HCV antigen was still detectable in 3 samples with undetectable (<615 IU/ml) RNA by bDNA, while no differences in clinical sensitivity were recorded in comparison with real-time PCR. These findings suggest that HCV-RNA and HCV antigen may be used at different time points in order to tailor therapy monitoring to individual needs.

A silybin-phospholipid complex prevents mitochondrial dysfunction in a rodent model of nonalcoholic steatohepatitis

Mitochondrial dysfunction and oxidative stress are determinant events in the pathogenesis of nonalcoholic steatohepatitis. Silybin has shown antioxidant, anti-inflammatory, and antifibrotic effects in chronic liver disease. We aimed to study the effect of the silybin-phospholipid complex (SILIPHOS) on liver redox balance and mitochondrial function in a dietary model of nonalcoholic steatohepatitis. To accomplish this, glutathione oxidation, mitochondrial oxygen uptake, proton leak, ATP homeostasis, and H(2)O(2) production rate were evaluated in isolated liver mitochondria from rats fed a methionine- and choline-deficient (MCD) diet and the MCD diet plus SILIPHOS for 7 and 14 weeks. Oxidative proteins, hydroxynonenal (HNE)- and malondialdehyde (MDA)-protein adducts, and mitochondrial membrane lipid composition were also measured. Treatment with SILIPHOS limited glutathione depletion and mitochondrial H(2)O(2) production. Moreover, SILIPHOS preserved mitochondrial bioenergetics and prevented mitochondrial proton leak and ATP reduction. Finally, SILIPHOS limited the formation of HNE- and MDA-protein adducts. In conclusion, SILIPHOS is effective in preventing severe oxidative stress and preserving hepatic mitochondrial bioenergetics in nonalcoholic steatohepatitis induced by the MCD diet. The modifications of mitochondrial membrane fatty acid composition induced by the MCD diet are partially prevented by SILIPHOS, conferring anti-inflammatory and antifibrotic effects. The increased vulnerability of lipid membranes to oxidative damage is limited by SILIPHOS through preserved mitochondrial function.

Entecavir for hepatitis B virus flare treatment in patients with Crohn's disease

Chronic hepatitis B virus (HBV) infection is a global health problem and has an increased prevalence in patients with Crohn's disease due to their increased requirement for high-risk procedures. A balance between viral replication and host immune response exists and drugs such as the immunosuppressive agents used to treat Crohn's disease may alter this balance. These may result in a hepatic flare, which manifests as high viremia, increased transaminase levels, and hepatic decompensation. The present study describes two cases of hepatic flare thought to be caused by treatment of acute Crohn's disease with systemic corticosteroids and/or azathioprine. Both patients presented with raised transaminase and gamma glutamyl transferase levels and viremia. One patient experienced a decrease in hepatic function, as evidenced by a reduced serum albumin (2.5g/ dL) and jaundice (total bilirubin 5.2 mg/dL), and hepatic decompensation, with ascites. Both patients were treated with the nucleoside analogue entecavir 0.5 mg/day and experienced reductions in HBV-DNA and hepatic enzyme levels within 4-7 days. The patient with decompensation received diuretic therapy and parenteral nutrition to support hepatic function and a clinical improvement was seen. Both patients were discharged 2 weeks after admission and, during follow-up, HBV-DNA levels became negative after 1 and 5 months, respectively. No adverse events were reported in either patient. To the best of our knowledge, this is the first documented report of treatment of HBV flare with entecavir in patients co-affected with Crohn's disease.

Targeting mitochondria: a new promising approach for the treatment of liver diseases

Mitochondrial dysfunction acts as a common pathogenetic mechanism in several acute and chronic liver diseases, such as Alcoholic and Non-Alcoholic Fatty Liver Disease (NAFLD), drug-induced steatohepatitis, viral hepatitis, biliary cirrhosis, hepatocellular carcinoma, ischemia/reperfusion injury and transplant rejection. In particular mitochondrial uncoupling,has been recently identified to play a determinant role in the pathogenesis of liver diseases by causing decrease of mitochondrial proton motive force and ATP depletion. Damaged mitochondria present defects in lipid homeostasis, bioenergetics impairment and overproduction of Reactive Oxygen Species (ROS), leading to lipid accumulation and oxidative stress. Dysfunctional and/or uncoupled mitochondria enhance the susceptibility of hepatocytes to cell death by necrosis, via ATP depletion, or by apoptosis, via membrane permeabilization. Thus, prevention of mitochondrial alterations promises to be an effective strategy for treatment of liver diseases. However, no therapy has proven to be absolutely effective, whereas those that are beneficial present several side effects. The present review summarizes the recent approaches in mitochondrial drug deliver systems and focuses on mitochondria-targeted molecules application in liver disease. New selective molecules and nanocarriers technology are also considered as potentially effective in the targeting of mitochondrial dysfunction in liver pathology.

Frailty syndrome is associated with altered circulating redox balance and increased markers of oxidative stress

Frailty syndrome (FS) is a condition described in aging and characterized by physical vulnerability to stress and lack of physiological reserve. In this study we aim to define whether circulating oxidative stress correlates to frailty in terms of glutathione balance and oxidative protein damage. In 62 elderly outpatients, classified as frail patients according to Fried's criteria, evaluation of reduced glutathione (GSH), oxidized glutathione (GSSG), tumor necrosis factor-alpha, malonaldehyde-(MDA) and 4-hydroxy-2,3-nonenal-(HNE) protein plasma adducts were performed. A significant increase in the GSSG was observed in patients with FS when compared to non-frail. No difference was shown in the GSH amount, suggesting a glutathione oxidation more than impairment of the synthesis. TNF-alpha, MDA- and HNE-adducts, were significantly higher in FS as compared to non-frail patients. A logistic regression model correlating FS with redox balance showed a close relationship between glutathione ratio (OR=1.8, 95% CI=1.2-2.5) and MDA adducts (OR=2.8, 95% CI=1.6-4.7) to frailty. Our findings show an association between oxidative imbalance and Frailty Syndrome. GSSG/GSH ratio and plasma protein adducts strongly predict the frailty conditions and seem to be reliable and easily measurable markers in the context of the multidimensional analysis of elderly patients.

Clinical impact of selective transarterial chemoembolization on hepatocellular carcinoma: A cohort study

AIM: To prospectively evaluate the short and long term clinical impact of selective transarterial chemoembolization (TACE) on liver function in patients with hepatocellular carcinoma (HCC). To assess side effects in relation to treatments. To analyze the overall survival and HCC progression free survival probability.

METHODS: One hundred and seventeen cirrhotic patients with HCC were enrolled. Baseline liver function included Child-Pugh score and serum levels of alanine-aminotransferase (ALT), prothrombin time (PT) and bilirubin. According to Cancer Liver Italian Program (CLIP) and Barcelona Clinic Liver Cancer (BCLC) staging systems, 71 patients were eligible for TACE; 32 had previously received treatment for HCC. No significant differences in liver function were observed between previously treated and not treated patients. TACE was performed by selective catheterization of the arteries nourishing the lesions. While hospitalized, patients underwent clinical, hematologic and ultrasonographic assessments. One month after TACE a CT scan was performed to assess tumor response. A second TACE was performed “on demand”. Liver function tests were checked in all patients every four months.

RESULTS: After first TACE, the mean Child-Pugh score increased from a mean baseline 5.62 ± 1.12 to 6.11 ± 1.57 at discharge time (P < 0.0001), decreasing after four months to 5.81 ± 0.73 (not significant). ALT, PT and bilirubin significantly (P < 0.0001) increased 24 h after TACE and progressively decreased until discharge. After the second TACE, variations in Child-Pugh score, ALT, PT and bilirubin were comparable to that described after the first TACE. No major complications were observed. The mean follow-up was 14.7 ± 6.3 mo (median: 16 mo). Only one patient died. No other patient experienced important long term worsening of clinical status. The overall survival probability at twenty-four months was 98.18% with a correspondent HCC progression free survival probability of 69%.

CONCLUSION: Selective TACE may produce significant, but transitory increases in ALT values, with no major impact on liver function and Child-Pugh score. Preservation of liver function is achievable also in patients previously treated with other therapeutic modalities and in patients undergoing multiple TACE cycles. Liver function can remain stable in the long-term, with optimal medium term survival. This result can be achieved through rigorous patient selection on the basis of tumour characteristics and clinical conditions.

[Alcohol-induced cardiac disease]

Excessive and chronic ethanol consumption exerts deleterious and diffused effects on the myocardium, independent of coronary atherosclerosis, arterial hypertension, valvular disease or congenital heart disease. Although the effects of chronic alcoholism on systolic cardiac function are well known, diastolic involvement has been evaluated only partially. This short review summarizes the experimental and clinical evidence for alcohol-induced cardiac disease.

Uncoupling protein-2 (UCP2) induces mitochondrial proton leak and increases susceptibility of non-alcoholic steatohepatitis (NASH) liver to ischaemia-reperfusion injury

BACKGROUND

The mechanisms of progression from fatty liver to steatohepatitis and cirrhosis are not well elucidated. Mitochondrial dysfunction represents a key factor in the progression of non-alcoholic steatohepatitis (NASH) as mitochondria are the main cellular site of fatty acid oxidation, ATP synthesis and reactive oxygen species (ROS) production.

AIMS

(1) To evaluate the role of the uncoupling protein 2 in controlling mitochondrial proton leak and ROS production in NASH rats and humans; and (2) to assess the acute liver damage induced by ischaemia-reperfusion in rats with NASH.

METHODS

Mitochondria were extracted from the livers of NASH humans and rats fed a methionine and choline deficient diet. Proton leak, H(2)O(2) synthesis, reduced glutathione/oxidised glutathione, 4-hydroxy-2-nonenal (HNE)-protein adducts, uncoupling protein-2 (UCP2) expression and ATP homeostasis were evaluated before and after ischaemia-reperfusion injury.

RESULTS

NASH mitochondria exhibited an increased rate of proton leak due to upregulation of UCP2. These results correlated with increased production of mitochondrial hydrogen peroxide and HNE-protein adducts, and decreased hepatic ATP content that was not dependent on mitochondrial ATPase dysfunction. The application of an ischaemia-reperfusion protocol to these livers strongly depleted hepatic ATP stores, significantly increased mitochondrial ROS production and impaired ATPase activity. Livers from patients with NASH exhibited UCP2 over-expression and mitochondrial oxidative stress.

CONCLUSIONS

Upregulation of UCP2 in human and rat NASH liver induces mitochondrial uncoupling, lowers the redox pressure on the mitochondrial respiratory chain and acts as a protective mechanism against damage progression but compromises the liver capacity to respond to additional acute energy demands, such as ischaemia-reperfusion. These findings suggest that UCP2-dependent mitochondria uncoupling is an important factor underlying events leading to NASH and cirrhosis.

Alterations of hepatic ATP homeostasis and respiratory chain during development of non-alcoholic steatohepatitis in a rodent model

BACKGROUND

Mitochondrial dysfunction is considered a key player in non-alcoholic steatohepatitis (NASH) but no data are available on the mitochondrial function and ATP homeostasis in the liver during NASH progression. In the present paper we evaluated the hepatic mitochondrial respiratory chain activity and ATP synthesis in a rodent model of NASH development.

MATERIALS AND METHODS

Male Wistar rats fed a High Fat/Methionine-Choline Deficient (MCD) diet to induce NASH or a control diet (SHAM), and sacrificed after 3, 7 and 11 weeks. The oxidative phosphorylation, the F(0)F(1)ATPase (ATP synthase) and the ATP content were assessed in liver mitochondria.

RESULTS

NASH mitochondria exhibited an increased rate of substrate oxidation at 3 weeks, which returned to below the normal level at 7 and 11 weeks, concomitantly with the coupling between the phosphorylation activity and the mitochondrial respiration (ADP/O). Uncoupling of NASH liver mitochondria did not allow the recovery of the maximal respiration rate at 7 and 11 weeks. The ATPase (ATP synthase) activity was similar in NASH and SHAM rats, but the mitochondrial ATP content was significantly lower in NASH livers.

CONCLUSIONS

The loss of hepatic ATP stores is not dependent on the F(0)F(1)-ATPase but resides in the respiratory chain. Dysfunction of both Complex I and II of the mitochondrial respiratory chain during NASH development implies a mitochondrial adaptive mechanism occurring in the early stages of NASH.

Postconditioning is an effective strategy to reduce renal ischaemia/reperfusion injury

BACKGROUND

Several recent studies have shown that a brief ischaemia applied during the onset of reperfusion (postconditioning) is cardioprotective in different animal models. The potential application of postconditioning to organs different from the heart, i.e. kidney, is not available and is investigated in the present study. We also tested the hypothesis that mitochondria play a central role in renal protection during reperfusion.

METHODS

Wistar rats were subjected to left nephrectomy and 90-min right kidney occlusion. In controls, the blood flow was restored without intervention. In postconditioned rats, complete reperfusion was preceded by 3 min, 6 min and 12 min of reperfusion in a consecutive sequence, each separated by 5 min of reocclusion. Animals were studied for 48 h. Mitochondrial respiratory chain function, rate of hydroperoxide production and carbonyl proteins were measured at the end of postconditioning and 24 h and 48 h after reperfusion.

RESULTS

BUN and creatinine significantly decreased in the postconditioning group as compared to control rats. Mitochondrial respiratory function was significantly impaired in control rats, mainly at the level of Complex II. Postconditioning significantly reduced this mitochondria impairment. The rate of mitochondrial peroxide production was higher in the control group than in the protected group at the end of postconditioning reperfusion. Moreover, mitochondrial protein oxidation was significantly higher in control rats than in the postconditioning group at the end of reperfusion. Conclusions. In the present study, postconditioning reduced renal functional injury and reduces mitochondria respiratory chain impairment, mitochondria peroxide production and protein damage.

Mitochondrial involvement in non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is an increasing recognized condition that may progress to end-stage liver disease. There are consistent evidences that mitochondrial dysfunction plays a central role in NASH whatever its origin. Mitochondria are the key controller of fatty acids removal and this is part of an intensive gene program that modifies hepatocytes to counteract the excessive fat storage. Mitochondrial dysfunction participates at different levels in NASH pathogenesis since it impairs fatty liver homeostasis and induces overproduction of ROS that in turn trigger lipid peroxidation, cytokines release and cell death. In this review we briefly recall the role of mitochondria in fat metabolism and energy homeostasis and focus on the role of mitochondrial impairment and uncoupling proteins in the pathophysiology of NASH progression. We suggest that mitochondrial respiratory chain, UCP2 and redox balance cooperate in a common pathway that permits to set down the mitochondrial redox pressure, limits the risk of oxidative damage, and allows the maximal rate of fat removal. When the environmental conditions change and high energy supply occurs, hepatocytes are unable to replace their ATP store and steatosis progress to NASH and cirrhosis. The beneficial effects of some drugs on mitochondrial function are also discussed.

Bioenergetics in aging: mitochondrial proton leak in aging rat liver, kidney and heart

Aging is associated with a decline in performance in many organs and loss of physiological performance can be due to free radicals. Mitochondria are incompletely coupled: during oxidative phosphorylation some of the redox energy is dissipated as natural proton leak across the inner membrane. To verify whether proton leak occurs in mitochondria during aging, we measured the mitochondrial respiratory chain activity, membrane potential and proton leak in liver, kidneys and heart of young and old rats. Mitochondria from old rats showed normal rates of Complex I and Complex II respiration. However, they had a lower membrane potential compared to mitochondria from younger rats. In addition, they exhibited an increased rate of proton conductance which partially dissipated the mitochondrial membrane potential when the rate of electron transport was suppressed. This could compromise energy homeostasis in aging cells in conditions that require additional energy supply and could minimize oxidative damage to DNA.

Evidence of lower oxidative stress in the air spaces of patients with reversible COPD

The mechanism responsible for the reversibility of airflow limitation in stable chronic obstructive pulmonary disease (COPD) patients is unknown. The aim of this study is to assess the relationship between the reversibility of airflow limitation, the redox balance and the inflammatory cells in the sputum of patients with stable COPD. For this purpose we examined 15 normal healthy control subjects and 20 nonatopic COPD patients. The COPD patients were divided into two groups: reversible COPD (increase in FEV1> 200 ml and/or > or =12> or = after 200 microg of inhaled salbutamol) or non-reversible COPD. GSH, GSSG were measured in induced sputum and blood. Protein carbonyls were evaluated by WB in sputum and IL-4 and IL-6 and TNF-alpha in plasma and sputum. GSH oxidation and protein oxidation were lower in reversible COPD patients than in those with no reversibility. The sputum eosinophil count was significantly higher in the reversible group than in the non-reversible group, and IL-4 concentration was higher in the same patients both in sputum and in plasma. In contrast, IL-6 and TNF-alpha were increased in non-reversible COPD patients in both biological samples. We conclude that airflow reversibility in COPD patients is associated with airway oxidative stress and activation of eosinophil inflammatory pattern in sputum and blood, suggesting that these patients could respond to specific pharmacological treatment.

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

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.

[Case report: RAEB in a patient with rheumatoid arthritis treated with methotrexate and infliximab]

Anti TNF-alpha drugs seem to be the new frontier of Rheumatoid Arthritis (RA) therapy. The association infliximab methotrexate has been approved for the treatment of RA not responding to the classic therapy, but the short clinical experience in using antiTNF-alpha molecules brings to segnalation of new risks or adverse events. We describe a case of a patient, treated for many years with classic RA therapy, which developed a refractory anemia after treatment with association infliximab-methotrexate.

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.

Oxidative injury in rat fatty liver exposed to ischemia-reperfusion is modulated by nutritional status

BACKGROUND AND AIMS

Oxidative stress contributes to ischemia-reperfusion injury in fatty livers. This study aimed to determine whether glycogen depletion influences this oxidative injury and whether the administration of glucose can be protective.

METHODS

Rats with choline deficiency-induced fatty liver underwent hepatic ischemia-reperfusion. Experimental groups: (1) fed rats; (2) 18 h fasted rats; (3) 18 h fasted rats supplemented with glucose prior to surgery. The thiobarbituric acid-reactive substances, protein carbonyls and total glutathione concentrations were measured in liver tissue and isolated mitochondria as parameters of oxidative stress before and after ischemia and during reperfusion. The mitochondrial F1-ATPase content and the serum alanine transaminase were also determined.

RESULTS

With respect to fed rats, fasted rats exhibited an increased oxidative injury in both liver tissue and isolated mitochondria throughout the experiment with the only exception of thiobarbituric acid-reactive substances, which were not affected by the nutritional status in liver tissue. Fasted rats showed a significantly lower F1-ATPase content and higher alanine transaminase levels. Glucose supplementation significantly reduced the fasting-associated exacerbation of oxidative stress and liver injury and the F1-ATPase exhaustion.

CONCLUSIONS

These data indicate that the pre-existing hepatic glycogen content modulates the oxidative damage in rat fatty livers exposed to ischemia-reperfusion injury and that the energetic substrate supplementation may represent a clinically feasible protective strategy.

The reduced tolerance of rat fatty liver to ischemia reperfusion is associated with mitochondrial oxidative injury

BACKGROUND

Oxidative stress contributes to the pathogenesis of hepatic ischemia-reperfusion injury. This study aimed to determine whether fatty degeneration affects the oxidative damage during warm ischemia reperfusion and whether mitochondria, the major intracellular site of energy synthesis, represent a preferential target of this injury.

MATERIALS AND METHODS

Fed rats with control or fatty liver induced by choline deficiency underwent 60' lobar ischemia and reperfusion. Oxidative damage was assessed by measuring in whole liver tissue and in isolated mitochondria the thiobarbituric acid-reactive substances (TBARs), protein carbonyls (PC), and total and oxidized glutathione (GSH and GSSG) concentrations. The mitochondrial F0-F1-ATPase content and the oxidative phosphorylation activity were also determined. Rat survival and ALT release were assessed as parameters of liver injury.

RESULTS

In the whole liver tissue, with the exception of TBARs, no differences were observed for GSH, GSSG, and PC between the two groups throughout all of the experiment. In contrast, in isolated mitochondria, fatty infiltration was associated with a mild oxidative imbalance already under basal conditions. The preischemic differences in the mitochondrial TBARs, PC, and GSSG levels were significantly amplified by reperfusion in the presence of steatosis. The enhanced oxidative damage was associated to a reduced F0-F1-ATPase content and oxidative phosphorylation activity in fatty liver mitochondria. Finally, serum ALT levels were significantly greater and survival significantly lower in rats with steatotic liver.

CONCLUSIONS

Fatty infiltration exacerbates mitochondrial oxidative injury during warm ischemia reperfusion. The increased oxidative stress can alter mitochondrial functions, including key processes for ATP synthesis, thus, contributing to the reduced tolerance to reperfusion injury.

Hepatic oxidative alterations in patients with extra-hepatic cholestasis. Effect of surgical drainage

BACKGROUND/AIMS

The mechanisms of liver injury in conditions of biliary obstruction are poorly understood. Hepatic oxidative injury has been observed in experimental models of cholestasis. Little is known in humans. This study aimed to gain more insights into the hepatic redox status in human cholestasis.

METHODS

Liver concentrations of total glutathione, protein sulfhydryls and malondialdehyde (end-product of lipid peroxidation) were measured in hepatic specimens of 12 patients with obstructive jaundice before and after the application of an external biliary drainage and in six control subjects.

RESULTS

Compared to control subjects, biliary obstructed patients showed significantly (P < 0.001) lower concentrations of hepatic glutathione and protein sulfhydryls, and higher (P < 0.001) levels of malondialdehyde, in the presence of comparable protein concentrations. Two-weeks after the application of external biliary drainage, cholestatic indices were significantly improved and the observed changes in glutathione, protein sulfhydryls and malondialdehyde levels, significantly decreased.

CONCLUSIONS

This study shows that cholestasis is associated with a decreased protein and non-protein sulfhydryl content in the liver and with an increased lipid peroxidation. These alterations reversed almost completely after biliary drainage, indicating the cholestasis itself as the determining factor for the redox status impairment observed in the liver of patients with extra-hepatic biliary obstruction.

[Genetics of late-onset Alzheimer's disease: vascular risk and beta-amyloid metabolism]

Progress in clinical and basic research of Alzheimer's disease (AD) suggested theoretical models of possible pathogenetic mechanisms, with a primary role of the genetic factors that have been implicated in AD. These can be divided into two main categories. First, the three genes in which mutations are known to result in early onset autosomal dominant familial AD (presenilins 1 and 2, and amyloid beta protein precursor [APP]): well characterized but that account for only a small proportion of AD cases. Secondly, late onset, sporadic AD is more common and evidence suggests that there is a genetic component to this type of disease. A number of genetic risk factors have been implicated that might increase the risk of developing sporadic disease: particularly, apolipoprotein E (apo E) polymorphism and many others suggested by linkage studies [alpha-macroglobulin, low density receptor protein (LRP1), bleomycin hydrolase], with a precise role in beta-amyloid metabolism and deposition. Many of these are controversial and studies have shown conflicting results, but apoE polymorphism seems to be only one of the possible genetic factors suggested to play a role in the multifactoral pathogenesis of AD. Regional and ethnic differences may affect the strength of association between apoE epsilon 4 allele and the disease, and we reported evidences of the decreasing frequency of epsilon 4 allele in AD patients and centenarians from Northern to Southern European regions. Finally, several genetic risk factors of vascular origin (angiotensin converting enzyme, methyltetrahydropholate-reductase, and NOS3 gene polymorphisms) have been implicated in the development of both vascular dementia and AD with conflicting results.

Modulation of endometrial redox balance during the menstrual cycle: relation with sex hormones

This study aimed to evaluate the effects of changes in sex hormones occurring during the menstrual cycle on the redox balance and lipid peroxidation in normal human endometrial cells. Forty women, ages 21-41 yr, who were admitted to the Department of Gynecology and Obstetrics of the University of Bari for routine checkups or were treated for benign uterine disease, underwent endometrial biopsy and venipuncture. On the basis of histological examination, patients were allocated as follows: 10 in the early proliferative phase, 12 in the late proliferative phase, 8 in the early secretory phase, and 10 in the late secretory phase. LH, FSH (immunoradiometric essay), estradiol (E2), and progesterone (P(4)) (RIA) were determined in plasma samples. On the endometrial specimens, total glutathione (GSH), oxidized GSH (GSSG), malondialdehyde, and GSH peroxidase activity (GSH-Px) were determined. Significant cycle-dependent changes in endometrial GSH-Px (P < 0.0001), GSH (P < 0.001), and GSSG as a percentage of GSH (P < 0.0001) were observed. Malondialdehyde did not show significant differences. A linear regression model correlating sex hormone changes with redox indexes was performed. A significant positive correlation was observed between E2 and GSH-Px (r = 0.74; P = 0.0001), E2 and GSSG, as percentage of total (r = 0.84; P < 0.0001); a negative correlation was found between E2 and GSH (r = -0.57; P = 0.0001). No significant correlation was found between P(4) or FSH and oxidative balance. LH was found to be correlated with GSH-Px (r = 0.66; P = 0.0001) and GSSG as percentage of GSH (r = 0.5; P < 0.001). We conclude that the hormonal pattern is involved in maintaining the optimal redox balance in endometrium, mainly through modulation of GSH level and metabolism.

Mitochondrial oxidative damage and myocardial fibrosis in rats chronically intoxicated with moderate doses of ethanol

Mitochondrial oxidative balance and myocardial fibrosis were investigated in pair-fed rats received ethanol (3%) or saccharose in drinking water for 8 weeks. The concentrations of glutathione, malondialdehyde, protein carbonyls and sulfhydrils were determined. The presence and distribution of fibronectin were detected by immunohistochemistry. The myocardial concentrations of reduced glutathione and protein sulfhydrils were lower in ethanol treated rats. The oxidised/reduced glutathione ratio, the levels of malondialdehyde and protein carbonyls were higher in ethanol-treated rats. The mitochondrial amount of proteins, glutathione and protein sulfhydrils were lower in ethanol treated rats, whereas the content of protein carbonyls and malondialdehyde were higher. Accumulation of fibronectin was detected at subepicardial and subendocardial districts in ethanol-treated rats, with moderate degree of fibrosis in 20% of the cases. In conclusion, moderate ethanol consumption is associated with oxidative damage to heart mitochondria and fibronectin deposition. These oxidative and ultrastuctural changes may be assumed as basic alterations in the development of alcoholic cardiomyopathy.

Increased oxidative stress in dimethylnitrosamine-induced liver fibrosis in the rat: effect of N-acetylcysteine and interferon-alpha

Oxidative stress may represent a common link between chronic liver damage and hepatic fibrosis. Antioxidants and interferon seem to protect against hepatic stellate cell (HSC) activation and liver fibrosis. This study evaluated (1) the effect of the profibrotic agent dimethylnitrosamine (DMN) on the hepatic oxidative balance in the rat; (2) the role played by the antioxidant agent N-acetylcysteine (NAC); and (3) the antifibrotic effects of two different types of interferon-alpha: recombinant alpha-2b (rIFN-alpha) and leukocyte alpha (LeIFN-alpha). Five groups of rats received: (1) saline; (2) DMN; (3) DMN + NAC; (4) DMN + rIFN-alpha; and (5) DMN + LeIFN-alpha. Oxidative balance was evaluated by hepatic glutathione, TBARs, protein carbonyl, and sulfhydryl determination. Fibrosis was determined by hepatic hydroxyproline content and fibronectin (FN) staining (immunohistochemistry). DMN rats showed a diffuse FN deposition, an impaired oxidative balance, and higher hepatic hydroxyproline levels compared to that of controls. NAC administration significantly reduced FN deposition, increased hepatic glutathione, and decreased TBARs and protein carbonyls. Administration of IFN-alpha exerted different effects according to the type used. Both IFNs decreased FN deposition; however, LeIFN-alpha significantly improved histology and oxidative parameters compared to those of untreated DMN and rats treated with rIFN-alpha. This study shows the role of free radicals in this model of hepatic fibrosis; the protective effect of NAC against liver fibrosis; and the antifibrotic effect exerted by IFN-alpha (particularly LeIFN-alpha) independent of its antiviral activity.

Mitochondrial oxidative injury and energy metabolism alteration in rat fatty liver: effect of the nutritional status

Hepatic steatosis is associated with mitochondrial oxidative alterations. This study aimed to characterize in a choline-deficient model of rat fatty liver whether this oxidative imbalance is related to an impairment of the capacity of ATP synthesis both under fed conditions and after starvation, which may sensitize mitochondria to oxidative injury. Mitochondria were isolated from normal and fatty livers of fed or 18-hour fasted rats. Oxidative injury was evaluated by measuring the mitochondrial content of thiobarbituric reactive substances, protein carbonyls, glutathione, and protein sulfhydryls. The mitochondrial F(0)F(1)-ATP synthase content, tissue ATP concentration, and liver histology were also determined. Compared with normal liver, under fed conditions, fatty livers showed a greater mitochondrial content of oxidized lipids and proteins together with a low concentration of sulfhydryls and glutathione. The mitochondrial catalytic beta-F(1) subunit of the F(0)F(1)-ATP synthase was about 35% lower in fatty livers. Hepatic ATP was also significantly reduced in fatty liver. Starvation exacerbated mitochondrial oxidative injury in both groups but to a greater extent in fatty livers. In the steatotic group, fasting induced a significant decrease of the ATP levels, which was accompanied by a 70% fall of the catalytic beta-F(1) subunit. These data indicate that the mitochondrial oxidative alterations in fatty livers are associated with an important reduction of the F(0)F(1)-ATP synthase. These changes, which are greatly exacerbated after starvation, may account for the reduced synthesis of the hepatic ATP observed in the presence of fatty infiltration.

Oxidative stress in symptom-free HCV carriers: relation with ALT flare-up

BACKGROUND

The reason why some hepatitis C virus carriers with normal aminotransferase activity present, during time, an activation of the disease, is unknown. The aim of this study was to assess the oxidative balance in such patients and to evaluate its possible role on the severity of disease.

MATERIALS AND METHODS

Histology, glutathione and malondialdehyde were determined in the liver of 30 HCV-RNA positive patients with persistently normal aminotransferase. Patients were followed-up for 18 months with plasmatic determinations of aminotransferase, ferritin, glutathione, malondialdehyde, carbonyl and sulphydryl protein levels (every 2 months) and serum HCV-RNA (every 3 months).

RESULTS

Four subjects had normal histology, whereas the remaining 26 showed mild/moderate chronic hepatitis. Hepatic glutathione and malondialdehyde concentrations were normal in 16 patients and clearly altered in the other 14. The hepatic redox state did not correlate with histology whereas it correlated with plasmatic oxidative markers. During the study, aminotransferase flared up in 11 patients, 9 of these (82%) having at enrollment an altered hepatic oxidative balance. Patients with aminotransferase elevation showed increased blood indices of oxidative stress, which occurred earlier than aminotransferase flare-ups. No oxidative stress was observed in the remaining subjects.

DISCUSSION

This study suggests that symptom-free HCV carriers with impaired redox state have a higher risk of aminotransferase flare-up; therefore the impaired oxidative balance may have a prognostic significance on disease activity.

Food deprivation exacerbates mitochondrial oxidative stress in rat liver exposed to ischemia-reperfusion injury

Mitochondria undergo oxidative damage during reperfusion of ischemic liver. Although nutritional status affects ischemia-reperfusion injury in the liver, its effect on mitochondrial damage has not been evaluated. Thus, this study was designed to determine whether starvation influences the oxidative balance in mitochondria isolated from livers exposed to warm ischemia-reperfusion. Fed and 18- and 36-h food-deprived rats underwent partial hepatic ischemia followed by reperfusion. Mitochondria were isolated before and after ischemia and during reperfusion. Serum alanine transaminase was measured to assess liver injury. The mitochondrial concentrations of malondialdehyde, protein carbonyls and glutathione were determined as indicators of oxidative injury. Cell ultrastructure was assessed by transmission electron microscopy. Transaminase levels were greater in 18-h food-deprived than fed rats (after 120 min of reperfusion: 3872 +/- 400 vs. 1138 +/- 59 U/L, P < 0.01). Mitochondrial glutathione was lower in food-deprived than fed rats before and after ischemia, and during reperfusion. Food deprivation also was associated with significantly greater lipid and protein oxidative damage. Finally, more ultrastructural damage was observed during reperfusion in mitochondria from food-deprived rats. Prolonging the length of food deprivation to 36 h exacerbated significantly both the mitochondrial oxidative injury and the release of serum transaminases in rats (after 120 min of reperfusion: 5438 +/- 504 U/L, P < 0.01). Food deprivation was associated with greater mitochondrial oxidative injury in rat livers exposed to warm ischemia-reperfusion, and the extent of oxidative damage in mitochondria increased with the length of food deprivation.

Thyrotoxic periodic paralysis in a Caucasian man in treatment for Graves' disease

Thyrotoxic periodic paralysis (TPP) is the main secondary form of hypokalemic periodic paralysis and is mostly associated with Graves' disease. Initially diagnosed in Asian countries, TPP has been sporadically reported in different populations of the Western World. Increased Na+/K(+)-ATPase activity seems to be responsible for the marked hypokalemia observed during the transient paralysis attacks. We report on a 35-year-old Italian man without history of hypokalemic periodic paralysis and hyperthyroidism, in treatment for Graves' disease, who suffered episodes of flaccid paralysis even with normal thyroid hormone levels. An insulin-glucose provocation test confirmed our diagnosis. Oral and parenteral potassium reverse the symptoms. Monitoring of thyroid function is also important to prevent further attacks.

Starvation impairs antioxidant defense in fatty livers of rats fed a choline-deficient diet

Although fatty liver (FL) is considered an innocuous condition, the frequent incidence of graft failure when FL are transplanted has renewed interest in the intracellular disorders causative of or consequent to fatty degeneration. Oxidative stress and nutritional status modulate the tolerance to reperfusion injury in control livers (CL), but very little is known in the case of FL. This study was designed to compare the oxidative balance in CL and FL from fed and food-deprived rats. Serum and liver samples were collected from fed and starved (18 h) rats with CL or FL induced by a choline-deficient diet. Hepatic injury was assessed by transaminase activities and histology. The hepatic concentrations of glutathione (GSH), vitamin C, alpha-tocopherol, thiobarbituric acid-reactive substances (TBARS) and protein carbonyls (PC) were measured. Fed rats with FL had significantly greater TBARS and lower alpha-tocopherol and vitamin C levels than those with CL, whereas GSH and PC concentrations were not affected. Starvation impaired the oxidative balance in both groups. However, compared with the other groups, FL from food-deprived rats generally had the lowest hepatic concentrations of alpha-tocopherol, vitamin C and GSH. Unlike in CL, protein oxidation occurred in FL. These data indicate that fatty liver induced by consumption of a choline-deficient diet is associated with a lower level of antioxidants, which results in lipid peroxidation. Starvation further affects these alterations and extends the damage to proteins. In conclusion, steatosis and starvation may act synergistically on the depletion of antioxidants, predisposing fatty livers to a reduced tolerance to oxidative injury.

Protein oxidation and lens opacity in humans

PURPOSE

Oxidative damage to lens proteins is a major factor leading to cataract formation. It is of pathogenic importance to determine a threshold of protein oxidation over which opacification of the lens takes place.

METHODS

Sixty-two lenses extracted from patients affected by idiopathic senile, diabetic, or myopic cataract were studied. Clear lenses were obtained from subjects undergoing enucleation (n = 10) or vitrectomy for giant retinal tears (n = 9), and were age- and sex-matched to those with cataract. The content of carbonyls and sulfhydryls (P-SH) in proteins in the lens was assessed using spectrophotometric assay.

RESULTS

An age-associated inverse relation (P < 0.01) was noted in the content of P-SH, the concentrations of which were also inversely related (P < 0.03) to the content of protein carbonyls. These changes were more pronounced in cataracts than in clear lenses and in diabetic and myopic cataracts when compared with senile cataracts. The drop of P-SH concentration occurred earlier in diabetic and in myopic cataracts than in senile cataracts. The accumulation of protein carbonyls > 2 nmol/mg protein and the decrease of P-SH below 12 to 10 nmol/mg protein were always accompanied by lens opacification.

CONCLUSIONS

Idiopathic senile, diabetic, and myopic cataractogenesis appear to be dependent on oxidative damage to lens proteins. This damage occurs earlier in myopic and diabetic patients. Values of P-SH below and protein carbonyls above their specific threshold were found to be predictive for the presence of cataract. Because increased oxidation was observed in clear lenses removed from myopic and diabetic subjects, oxidation may be involved in the pathogenesis of these forms of human cataract.

Chronic ethanol administration induces oxidative alterations and functional impairment of pancreatic mitochondria in the rat

Pancreas is known to be vulnerable to ethanol (ETOH) at high doses, but little is known about the effect of lower doses. Therefore, in this study, the levels of glutathione (GSH), sulfhydryl proteins (P-SH), carbonyl proteins, malondialdehyde (MDA), and adenosine triphosphate (ATP) production were determined in the pancreatic tissue and mitochondria of rats fed for 8 weeks with 3% ETOH. ETOH decreased the pancreatic pool of ATP, while GSH and P-SH also decreased in mitochondria. MDA concentrations increased both in the pancreas and mitochondria, while carbonyl proteins increased only in mitochondria. Pancreatic cells of ETOH-treated rats were frequently affected by cytoplasmic vacuolization and swelling; these alterations were often associated with ductular dilatation. In conclusion, ETOH produces oxidative and morphologic alterations in the pancreas of the rat, including impairment of mitochondria. These effects may represent basic mechanisms of ETOH-induced pancreatic injury.

An update on the role of free radicals and antioxidant defense in human disease

Mounting clinical and experimental evidence indicates that free radicals play important roles in many physiological and pathological conditions. The wider application of free radical measurement has increased awareness of functional implications of radical-induced impairment of the oxidative/antioxidative balance. In the following review, the role of oxygen free radicals in some human and experimental pathological conditions is described, with particular emphasis on the mechanisms by which they produce oxidative damage to lipids, proteins, and nucleic bases. The role of free radicals and the activation of the antioxidant systems in arteriosclerosis and ageing, diabetes, ischemia/reperfusion injury, ethanol intoxication, and liver steatosis is discussed. Therapeutic approaches to the use of antioxidants have been described and prospects for clinical use have been considered.

Mitochondrial oxidative alterations following partial hepatectomy

Mitochondria, isolated from rat livers during the early phase of liver regeneration (7-24 h after partial hepatectomy), show: (i) decrease in the rate of ATP synthesis; (ii) increase of malondialdehyde and of oxidized protein production; (iii) decrease of the content of intramitochondrial glutathione and of protein thiols on mitochondrial proteins; (iv) increase of the glutathione bound to mitochondrial proteins by disulfide bonds. These observations suggest an increase of production of oxygen radicals in liver mitochondria, following partial hepatectomy, which can alter the function of the enzymes involved in the oxidative phosphorylation. Blue-native gel electrophoresis of rat liver mitochondria, isolated after partial hepatectomy, shows, during the early phase of liver regeneration (0-24 h after partial hepatectomy), a progressive decrease of the content of F0F1-ATP synthase complex. The amount of glutathione bound to the F0F1-ATP synthase, electroeluted from the blue-native gels, progressively increased during the early phase of liver regeneration. It is concluded that partial hepatectomy causes mitochondrial oxidative stress that, in turn, modifies proteins (such as F0F1-ATP synthase) involved in the mitochondrial oxidative phosphorylation.

Oxidative retinal products and ocular damages in diabetic patients

Several evidences suggest a retinal participation to the genesis of diabetic eye complications by means of an increased free radical production at this level. However, no direct proof exists that this happens in humans in vivo. Therefore, the concentrations of malondialdehyde (MDA), carbonyl and sulfhydryl (P-SH) proteins, and vitamin E have been assessed in the subretinal fluid (SF) of patients affected by retinal detachment. Diabetic (n = 19) and nondiabetic (n = 21 ) subjects with comparable age, degree of myopia, and duration of the retinal detachment were considered. A control group of n = 7 subjects was included. The SF was collected after drainage during surgery. The concentrations of total proteins, P-SH, and carbonyl proteins were determined with spectrophotometric methods; the levels of MDA and vitamin E were measured by HPLC. The protein concentration in SF did not differ among groups. A higher concentration of MDA (p < .01) and carbonyl proteins (p < .02) were found in diabetic compared to nondiabetic subjects. Diabetic patients also showed a lower content of P-SH (p < .002) and vitamin E (p < .001) compared to nondiabetic subjects. All these parameters were more markedly altered in patients affected by proliferative diabetic retinopathy and significantly differed between patients and control subjects. In conclusion, oxidative events are associated with retinal detachment in humans. This evidence strongly suggests that the retina is a source of free radical production under certain conditions, such as diabetes.

Gastric and intestinal ethanol toxicity in the rat. Effect on glutathione level and role of alcohol and acetaldehyde metabolisms

BACKGROUND/AIMS

This study investigated the dose- and time-dependent effect of ethanol on gastric and intestinal glutathione and protein oxidative state in the rat.

METHODS

Rats received 1 or 4 g/kg of 25% ethanol solution orally or isocaloric glucose. Some rats received diethylmaleate, cimetidine or cyanamide before ethanol (1 g/kg). Glutathione, carbonyl proteins and histological damage were evaluated in the gastric and intestinal mucosa 6 hours after treatment.

RESULTS

An increase in glutathione was observed 2 to 6 hours after 1 g/kg of ethanol both in the gastric and intestinal mucosa, whereas 4 g/kg decreased glutathione. The rise in glutathione after ethanol was associated with increased levels of its oxidized form; however, the total/oxidized ratio was significantly decreased only in the intestinal tract. Diethylmaleate depleted mucosal glutathione, while the subsequent ingestion of ethanol increased it. Unlike stomach, intestine showed a significant increase in carbonyl proteins and marked histological lesions after ethanol ingestion. Cimetidine and cyanamide inhibited by 50% the activity of alcohol dehydrogenase and by 80% aldehyde dehydrogenase, respectively, in the gastric and intestinal mucosa. Cyanamide significantly enhanced ethanol-induced protein oxidation and mucosal injury in the stomach. No such effect was observed in the intestine.

CONCLUSIONS

The increase of glutathione after ingestion of low amounts of ethanol appears to be an adaptive mechanism against ethanol toxicity. Depletion of glutathione increased protein oxidation and the extent of histological damage in ethanol-treated rats. At gastric level, the effects of ethanol are exaggerated by the inhibition of acetaldehyde metabolism; while intestinal damages appear to be ascribed to ethanol itself.

Ethanol-induced changes of intracellular thiol compartmentation and protein redox status in the rat liver: effect of tauroursodeoxycholate

BACKGROUND/AIMS

Ethanol impairs cellular antioxidant defense and protein metabolism. Hydrophilic bile acids are protective against ethanol-induced cytotoxicity. This study investigated the compartmentation of intracellular thiol and protein redox status after acute ethanol intoxication in the liver and the effect of tauroursodeoxycholate pretreatment.

METHODS

The concentrations of total glutathione, glutathione bound to proteins, sulfhydryl proteins, carbonyl proteins and malondialdehyde were measured in hepatic cytosol, mitochondria and nuclei after oral administration of 25% ethanol (4 g/kg) or isocaloric carbohydrate solution to rats. The metabolisms of ethanol and acetaldehyde were investigated by giving 4-methylpyrazole (1 mmol/kg i.p.) or cyanamide (15 mg/kg i.p.) 1 h prior to ethanol ingestion. One group of rats received tauroursodeoxycholate (12 mg/kg p.os) 1 h before ethanol ingestion.

RESULTS

Ethanol significantly decreased the glutathione concentrations. Significant increases in glutathione bound to proteins, carbonyl protein and malondialdehyde concentrations were also noted, especially at the mitochondrial level. Enhanced carbonyl protein formation was also observed (p < 0.01). The inhibition of acetaldehyde metabolism, but not ethanol metabolism, exaggerated the alterations produced by ethanol. Pretreatment with tauroursodeoxycholate significantly reduced lipid and protein oxidation, particularly in mitochondria. By contrast, no changes were observed in glutathione content and compartmentation.

CONCLUSIONS

Ethanol intoxication differentially impairs thiol and protein redox status in the subcellular fractions of rat liver. These alterations seem dependent on acetaldehyde rather than ethanol. Tauroursodeoxycholate administration protects proteins and lipids from ethanol-induced oxidative damage without influencing the glutathione content and compartmentation.