MiR-29b antagonizes the pro-inflammatory tumor-promoting activity of multiple myeloma-educated dendritic cells.

Dendritic cells (DCs) have a key role in regulating tumor immunity, tumor cell growth and drug resistance. We hypothesized that multiple myeloma (MM) cells might recruit and reprogram DCs to a tumor-permissive phenotype by changes within their microRNA (miRNA) network. By analyzing six different miRNA-profiling data sets, miR-29b was identified as the only miRNA upregulated in normal mature DCs and significantly downregulated in tumor-associated DCs. This finding was validated in primary DCs co-cultured in vitro with MM cell lines and in primary bone marrow DCs from MM patients. In DCs co-cultured with MM cells, enforced expression of miR-29b counteracted pro-inflammatory pathways, including signal transducer and activator of transcription 3 and nuclear factor-κB, and cytokine/chemokine signaling networks, which correlated with patients' adverse prognosis and development of bone disease. Moreover, miR-29b downregulated interleukin-23 in vitro and in the SCID-synth-hu in vivo model, and antagonized a Th17 inflammatory response. All together, these effects translated into strong anti-proliferative activity and reduction of genomic instability of MM cells. Our study demonstrates that MM reprograms the DCs functional phenotype by downregulating miR-29b whose reconstitution impairs DCs ability to sustain MM cell growth and survival. These results underscore miR-29b as an innovative and attractive candidate for miRNA-based immune therapy of MM.

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.

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.

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.

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.

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.

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 percent Sevoflurane and 6 percent Desflurane, respectively. Blood samples were collected prior to induction (T0 bas), 60min and 24h postoperatively (T1 60 and T2 24 h). In Group P, GSH increased on T1 60 and returned to baseline on T24h, while TEAC remained unmodified; in Groups S, GSH and TEAC decreased on T1 60 in Group D, on T1 60 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.

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.

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.

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.

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.

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.

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.

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.