Genotype effects on the antioxidant enzymes activity and mRNA expression in liver and kidney tissues of autoimmune-prone MRL/MpJ-lpr/lpr mice

Plasma α-Glutathione S-Transferase Evaluation in Patients with Acute and Chronic Liver Injury

High concentration of alpha-glutathione S-transferase (α-GST) in the liver and its short half-life make this enzyme clinically useful in assessing hepatocellular damage. We aimed to investigate the significance of α-GST evaluation in monitoring of liver injury in acute and chronic liver diseases. 20 healthy volunteers and 52 patients were included in the study. The patients were divided into three groups: group I (acute viral hepatitis B or C), group II (chronic hepatitis B or C), and group III (chronic liver disease or cirrhosis with different etiologies). The concentration of α-GST and the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured in all examined groups. α-GST, ALT, and AST were statistically higher in all patient groups than in the control group. Statistically higher values of all assessed parameters were observed in group I compared with remaining patients. Statistically higher activities of ALT and AST are observed in group III compared with group II. Significant positive correlations were noted between α-GST and ALT/AST in groups I and III. The results indicate that the assay of α-GST in combination with the other conventional markers may be found as a confirmatory test for hepatocellular damage.

Catalase and PPARg2 genotype and risk of systemic lupus erythematosus in Koreans

Catalase (CAT) and peroxisome proliferator activated receptor-g2 (PPARg2) are important regulators of oxidative stress and inflammation, which may contribute to the development of systemic lupus erythematosus (SLE). The objective of this study was to investigate the effects of genetic polymorphisms of CAT and PPARg2 on risk and severity of SLE in a Korean population. DNA was isolated from blood samples collected from 345 patients with SLE and 400 controls. Genotyping for the 2262C!T polymorphism of CAT and the Pro12Ala polymorphism of PPARg2 were performed by PCR-RFLP analysis. The severity of SLE was assessed using the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) damage index (SDI). No association was observed between genotypes for any of the clinical manifestations of SLE. CAT and PPARg2 genotypes were not associated with either risk or severity of SLE. For subjects who were carriers of the high activity Tallele for CATand have the Pro/Pro genotype for PPARg2, the odds ratio (95% confidence interval) for risk of SLE was 0.45 (0.23-1.08). Our results suggest that genetic polymorphisms of CAT and PPARg2 do not play a significant role in the development of SLE in a Korean population. A possible protective effect of a combined genotype warrants further investigation.

Modulatory Effects of Mild Carbon Monoxide Exposure in the Developing Mouse Cochlea

Carbon monoxide (CO) is well known as a highly toxic poison at high concentrations, yet in physiologic amounts it is an endogenous biological messenger in organs such as the internal ear and brain. In this study we tested the hypothesis that chronic very mild CO exposure at concentrations 25-ppm increases the expression of oxidative stress protecting enzymes within the cellular milieu of the developing inner ear (cochlea) of the normal CD-1 mouse. In addition we tested also the hypothesis that CO can decrease the pre-existing condition of oxidative stress in the mouse model for the human medical condition systemic lupus erythematosus by increasing two protective enzymes heme-oxygenase-1 (HO-1), and superoxide dismutase-2 (SOD-2). CD-1 and MRL/lpr mice were exposed to mild CO concentrations (25 ppm in air) from prenatal only and prenatal followed by early postnatal day 5 to postnatal day 20. The expression of cell markers specific for oxidative stress, and related neural/endothelial markers were investigated at the level of the gene products by immunohistochemistry, proteomics and mRNA expression (quantitative real time-PCR). We found that in the CD-1 and MRL/lpr mouse cochlea SOD-2 and HO-1 were upregulated. In this mouse model of autoimmune disease defense mechanism are attenuated, thus mild CO exposure is beneficial. Several genes (mRNA) and proteins detected by proteomics involved in cellular protection were upregulated in the CO exposed CD-1 mouse and the MRL/lpr mouse.

Catalase -262C>T polymorphism in systemic lupus erythematosus in Poland

It has been reported that reactive oxygen species contribute to pathogenesis of systemic lupus erythematosus (SLE). Catalase (CAT) -330C>T transition, known also as -262C>T, generates three genotypes. The CAT -330CC genotype is associated with a significantly lower CAT expression in comparison to -330CT and -330CT genotypes. Therefore, using restriction length fragment polymorphism analysis, we compared the frequencies of CAT -330C>T polymorphic variants between SLE patients (n = 102) and controls (n = 199). We did not observe significant differences in the prevalence of CAT -330C>T polymorphic variants in SLE patients and controls. However, we found that the CAT -330CC genotype (recessive model) showed a significant association with thrombocytopenia OR = 7.314 (1.977-27.057, P = 0.0017). We also observed that the CAT -330CC genotype (recessive model) is linked with leukopenia OR = 3.232 (1.361-7.676, P = 0.0118), renal manifestations OR = 2.403 (1.085-5.321, P = 0.0471) and presence of anti-snRNP Ab OR = 4.206 (95% CI = 1.405-12.590, P = 0.0131), and anti-Scl-70 Ab, OR = 3.143 (95% CI = 1.171-8.433, P = 0.0343) in SLE patients. Our findings suggest that the CAT -330CC genotype may contribute to some clinical manifestations in patients with SLE.

Phase 2 enzyme induction by conjugated linoleic acid improves lupus-associated oxidative stress

Conjugated linoleic acid (CLA) exhibits anticancer and anti-inflammatory properties. Its ability to increase total GSH (GSH+GSSG) amount and gamma-glutamylcysteine ligase (gammaGCL) protein expression was recently associated with the inhibition of typical pathological signs in MRL/MpJ-Fas(lpr) mice (MRL/lpr). In the present study the ability of CLA to modulate oxidative stress and phase 2 enzyme activity in the same animal model was investigated. Disease severity was associated with age-dependent production of anti-double-stranded DNA antibodies (anti-dsDNA IgGs) and with enhanced extent of oxidative stress markers: reduced total GSH, increased protein 3-nitrotyrosines (3-NT), and protein-bound carbonyl (PC) amounts. To examine the effect of CLA on antioxidant status, CLA or olive oil (as control) was administered to pregnant MRL/lpr mice. Significantly higher total GSH and Trolox equivalent antioxidant capacity (TEAC) levels were measured in serum of CLA-treated dams (and their pups), as compared with controls. Finally, the antioxidant and chemopreventive properties of CLA were investigated in old MRL/lpr mice. Sera of CLA-treated mice contained higher concentrations of total GSH which were negatively correlated with the levels of oxidative stress markers. Moreover, increased GSH, gammaGCL, glutathione S-transferase (GSTs), and NAD(P)H:quinone oxidoreductase (NQO1) activities were measured in liver and spleen of CLA-treated animals. In conclusion our data indicate that the activation of detoxifying enzymes may be one of the mechanisms whereby dietary CLA down-regulates oxidative stress in MRL/lpr mice.

Conjugated linoleic acid enhances glutathione synthesis and attenuates pathological signs in MRL/MpJ-Faslpr mice

Conjugated linoleic acid (CLA), a naturally occurring peroxisome proliferator-activated receptor gamma (PPAR gamma) ligand, exhibits proapoptotic, immunomodulatory, and anticancer properties. In this study, we examined the biological effects of CLA administration in the MRL/MpJ-Fas(lpr) mouse, an animal model of systemic lupus erythematosus (SLE). We found that CLA exerted apparently opposed activities in in vitro experiments, depending on its concentration: 100 microM CLA downregulated IFN gamma synthesis and cell proliferation of splenocytes, in association with apoptosis induction and a decrease of intracellular thiols (GSH + GSSG), whereas 25 microM CLA did not significantly influence cell proliferation but enhanced the expression of gamma-glutamylcysteine ligase catalytic subunit (GCLC) and intracellular GSH concentration. Interestingly, the antiproliferative effect at 100 microM was not inhibited by the PPAR gamma antagonist GW9662. In vivo, CLA administration drastically reduced SLE signs (splenomegaly, autoantibodies, and cytokine synthesis), a condition paralleled by the enhancement of GCLC expression and intracellular GSH content. Moreover, CLA administration significantly downregulated nuclear factor kappaB activity independent of PPAR gamma activation and apoptosis induction. In conclusion, enhanced GSH content and GCLC expression in CLA-treated mice suggest a novel biochemical mechanism underlying its immunomodulatory activity and the beneficial effects on murine SLE signs.

Opposite effects of low and high dose supplementation of vitamin E on survival of MRL/lpr mice

OBJECTIVE

The purpose of this study is to investigate the effects of vitamin E supplementation on the autoimmune disease course in MRL/lymphoproliferative mice.

METHODS

Three-month-old MRL/lymphoproliferative lpr female mice were fed an AIN-76 diet containing 50 mg/kg (control), 250 mg/kg (E5), 375 mg/kg (E7.5), or 500 mg/kg (E10) all-rac-alpha-tocopheryl acetate. Eight mice per group were killed for analysis after two months of experimental diets, and the rest of the mice were followed up to observe their proteinuria levels and life span.

RESULTS

The data suggest that the life span of the E5 group was longer than the E10 group. Though alpha-tocopherol content in the plasma, liver, and kidneys increased in the mice fed the diet supplemented with vitamin E, the thiobarbituric acid reactive substance values in the liver and kidneys among these groups were not significantly different. IgM anti-ds-DNA and anticardiolipin antibodies were significantly higher in the E10 group than in those of the other groups. Phytohemagglutinin-stimulated interleukin (IL)-2 secretion was significantly lower, but concanavalinA-stimulated IL-4 and IL-10 production was significantly higher in the E10 group compared with the control group. The in vitro study also showed decreased IL-2 secretion and messenger RNA expression in phytohemagglutinin-stimulated splenocytes cultured in medium supplemented with high doses of vitamin E, but increased IL-2 with low doses of vitamin E.

CONCLUSIONS

Our data suggest that low and high dose supplementation of vitamin E has the opposite effect on the survival of MRL/lpr mice. The inhibitory effect of Th1 from high vitamin E content may not be beneficial for those suffering from Th2 prone autoimmune diseases, such as systemic lupus erythematosus.

Inhibition of osteoporosis in autoimmune disease prone MRL/Mpj-Fas(lpr) mice by N-3 fatty acids

OBJECTIVE

Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease involving the breakdown of cartilage and juxta-articular bone, which is often accompanied by decreased bone mineral density (BMD) and increased risk of fracture. Anti-inflammatory omega-3 fatty acids may prevent arthritis and bone loss in MRL/lpr mice model of arthritis and in humans.

METHODS

In this study, the effect of long term feeding of 10% dietary n-3 (fish oil (FO)) and n-6 (corn oil (CO)) fatty acids begun at 6 weeks of age on bone mineral density (BMD) in different bone regions in an MRL/lpr female mouse model of RA was measured at 6, 9, and 12 months of age by dual energy x-ray absorptiometry (DEXA). After sacrificing the mice at 12 months of age, antioxidant enzyme activities were measured in spleen, mRNA for receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG) was measured by RT-PCR in lymph nodes, and synovitis was measured in leg joints.

RESULTS

At 6, 9 and 12 months of age, BMD was significantly higher (p < 0.05) in distal femur, proximal tibia, and lumbar spine of FO fed mice than those of CO fed mice. Spleen catalase (CAT) and superoxide dismutase (SOD) activities were also significantly higher (p < 0.01) in FO fed mice than in CO fed mice. Histology of knee joints revealed mild synovitis in CO fed mice, which was not present in FO fed mice. RT-PCR analysis of lymph nodes revealed decreased RANKL mRNA (p < 0.001) expression and enhanced OPG mRNA expression (p < 0.01) in FO fed mice compared to CO fed mice.

CONCLUSIONS

These results suggest beneficial effects of long-term FO feeding in maintaining higher BMD and lower synovitis in this mouse model. These beneficial effects may be due, in part, to increased activity of antioxidant enzymes, decreased expression of RANKL, and increased expression of OPG in FO fed mice thereby altering the RANKL/OPG ratio. These significant beneficial effects on BMD suggest that FO may serve as an effective dietary supplement to prevent BMD loss in patients with RA.

The effects of vitamin E supplementation on autoimmune-prone New Zealand black x New Zealand white F1 mice fed an oxidised oil diet

The purpose of the present study was to investigate the effect of vitamin E supplementation on autoimmune disease in New Zealand blackxNew Zealand white F1 (NZB/W F1) female mice fed an oxidised oil diet. First, 5-month-old mice were fed an AIN-76 diet containing either 150 g fresh soyabean oil/kg (15S), 50 g fresh soyabean oil/kg + 100 g oxidised frying oil/kg (5S10F) or 5S10F supplemented with all-rac-alpha-tocopheryl acetate at 275 mg/kg diet level (5S10F5E) or 550 mg/kg (5S10F10E), respectively, in experiment 1. The results showed that mice fed the 5S10F10E diet had a lower anti-double-stranded DNA IgG antibody level and a longer lifespan than those fed the 15S and 5S10F diets. Therefore, the 5S10F and 5S10F10E treatments were repeated in experiment 2 for further analysis. The results showed that vitamin E supplementation in the oxidised oil significantly decreased thiobarbituric acid-reactive substance values in the kidney and spleen of NZB/W F1 mice. Interferon-gamma and IL-6 production by mitogen-stimulated splenocytes decreased in mice fed the 5S10F10E diet, whereas the secretion of IL-2 and IL-10 was not affected. The percentage of T-cells was significantly higher and that of MHC class II-bearing cells was lower in the spleens of the 5S10F10E group. The 5S10F10E group had a significantly higher linoleic acid (18 : 2n-6) composition than the 5S10F diet group. Therefore, vitamin E supplementation in oxidised oil might decrease oxidative stress, anti-double-stranded DNA IgG antibody, regulate cytokines and lymphocyte subsets, and subsequently alleviate the severity of autoimmune disease such as systemic lupus erythematosus under oxidative stress.

Effect of dietary n-3 and n-6 oils with and without food restriction on activity of antioxidant enzymes and lipid peroxidation in livers of cyclophosphamide treated autoimmune-prone NZB/W female mice

OBJECTIVE

Cyclophosphamide (CTX), an alkylating agent, is extensively used in the treatment of lupus nephritis, but its administration has been associated with free radical mediated oxidative stress. The present study was designed to investigate the effect of dietary corn oil (CO), fish oil (FO) and food restriction (FR) on the activities of hepatic antioxidant enzymes, fatty acid composition and lipid peroxidation following CTX administration in autoimmune-prone NZB/W female mice.

METHODS

Autoimmune-prone NZB/W female mice were fed either ad libitum (AL) or food restricted (60% of AL intake), semipurified diets containing 5% CO or 5% FO supplemented with equal levels of antioxidants and injected with either phosphate buffered saline (PBS), or CTX (50 mg/kg body weight) every 10 days. Proteinuria was measured biweekly. The treatment was stopped at 10 months and diets were continued until the mice were killed at 12 months. Fatty acid composition, activity of antioxidant enzymes and lipid peroxidation were analyzed in liver homogenates, and anti-DNA antibodies were analyzed in the serum.

RESULTS

Mice in the FO/AL dietary group exhibited significantly higher liver catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities compared to the CO/AL dietary group. CTX significantly decreased SOD and GSH-Px activity in the FO/AL group and CAT and GSH-Px in the CO/AL group. In AL fed mice given CTX, activities of CAT, GSH-Px and GST were significantly higher in mice fed FO diets than in mice fed CO diets. FR increased the activity of enzymes in both the CO and FO diet groups. In FR mice, CTX decreased CAT and GSH-Px activity in both the CO and FO dietary groups, but glutathione S-transferase (GST) only in the CO group. The decrease in SOD activity was not significant in either of the restricted groups. CTX significantly increased generation of thiobarbituric acid reactive substances (TBARS) in both AL groups. FR significantly decreased lipid peroxidation in both the CO and FO groups, with or without CTX. CTX decreased serum anti-DNA antibody levels in both the CO and FO dietary groups. FR also decreased antibody titer in both the CO and FO dietary groups, and it was decreased further with CTX treatment. FO fed animals had higher levels of n-3 fatty acids, whereas CO fed animals had high levels of n-6 fatty acids. CTX significantly increased 20:4 and decreased 18:1 in CO/AL fed animals, whereas it increased 18:1 and decreased 22:6 in FO/AL fed animals.

CONCLUSIONS

Results obtained in the present study suggests that FO and, more significantly, FO combined with FR can have a beneficial effect in hepatic tissues subjected to CTX induced oxidative stress by regulating the activity of antioxidant enzymes. In addition, the study also indicates that n-3 and n-6 dietary lipids are susceptible to lipid peroxidation, particularly in the presence of a prooxidant like CTX, and that FR is beneficial in decreasing lipid peroxidation. The study also suggests that FO and CTX can have additive effects in preventing kidney disease in NZB/W mice.

Effects of dietary omega3 and omega6 lipids and vitamin E on chemokine levels in autoimmune-prone MRL/MpJ-lpr/lpr mice

Elevated levels of chemokines, such as Regulated upon Activation, Normal T cell Expressed and Secreted (RANTES), Monocyte Chemotactic Protein-1 (MCP-1), Macrophage Inflammatory Protein-1alpha (MIP-1alpha), and Macrophage Inflammatory Protein-1beta (MIP-1beta) have been found in rheumatoid arthritis (RA) and juvenile arthritis (JA), and they may be associated with the pathogenesis of these diseases. These chemokines are implicated in the migration of specific leukocytes into the joints. Omega-3 (omega3) fatty acid rich-fish oil (FO) and vitamin E may delay the progress of certain autoimmune diseases. The present study was designed to understand the effects of dietary lipids (omega-6 and omega-3 fatty acids) and vitamin E on the production of chemokines in autoimmune-prone MRL/lpr (a mouse model for RA) and congenic control MRL/++ mice. The MRL mice were fed for 4.5 months omega-6 and omega-3 diets that varied in lipid sources (corn oil; CO and fish oil; FO) and vitamin E levels (269 I.U./kg and 694 I.U./kg diet). Spleen cells were isolated and cultured aseptically in the presence of PHA for 48 h at 37 degrees C and the levels of chemokines (RANTES, JE/MCP-1 and MIP-1alpha) were determined in the cell-free supernatants. The levels of RANTES and JE/MCP-1 were significantly higher in MRL/lpr mice compared to MRL/++ mice. The FO had differential effect on RANTES and MCP-1 production by spleen cells. The production of RANTES and JE/MCP-1 by spleen cells in mice fed the FO diets was significantly lower than in mice fed the CO diets (p < 0.0001). The levels of vitamin E did not affect the production of RANTES and JE/MCP-1. The levels of vitamin E had a significant effect on MIP-1alpha as the spleen cells of mice fed diets containing 694 IU/kg diet of vitamin E produced significantly higher levels of MIP-1alpha compared to the group of mice fed the diets containing 269 IU of vitamin E (p < 0.0001). The data obtained from this study in MRL/lpr and MRL/++ mice suggest that FO diets containing omega-3 fatty acids are beneficial in decreasing the levels of certain pro-inflammatory chemokines (RANTES and MCP-1) thereby delaying the onset of and severity of autoimmune symptoms in MRL/lpr mouse model.

Nitric oxide synthase 2 and cyclooxygenase 2 interactions in inflammation

Nitric oxide (NO) and prostaglandin (PG) E2 produced by NO synthase type 2 (NOS2) and cyclooxygenase type 2 (COX2), respectively, are important mediators in inflammation. There is much information regarding their roles in models of inflammation in mice and in humans with diseases such as rheumatoid arthritis (RA). A variety of stimuli including cytokines, microbial components, immune complexes, and mechanical stress can induce both NOS2 and COX2 mRNA transcription and protein synthesis and enhance inflammation. This has been demonstrated in both mice and humans. NOS2-specific inhibitors reduce inflammation in mice, and COX2-specific inhibitors reduce inflammation in mice and in humans. There is significant cross-talk between PGE2/NO and COX2/NOS2. Treatments that inhibit both NOS2 and COX2 should provide the most potent antiinflammatory effects.

Quantitative trait locus analysis of plasma lipoprotein levels in an autoimmune mouse model : interactions between lipoprotein metabolism, autoimmune disease, and atherogenesis

The autoimmune MRL/lpr mouse strain, a model for systemic lupus erythematosus, exhibited an unusual plasma lipoprotein profile, suggesting a possible interaction of autoimmune disease and lipoprotein metabolism. In an effort to examine the genetic basis of such interactions, and to study their relationship to atherogenesis, we performed a quantitative trait locus analysis using a total of 272 (MRL/lprxBALB/cJ) second generation (F2) intercross mice. These mice were examined for levels of total plasma cholesterol, HDL cholesterol, VLDL and LDL cholesterol, unesterified cholesterol, autoantibodies, and aortic fatty streak lesions. Using a genome scan approach, we identified 4 quantitative trait loci controlling plasma lipoprotein levels on chromosomes (Chrs) 5, 8, 15, and 19. The locus on Chr 15 exhibited lod scores of 11.1 for total cholesterol and 6.7 for VLDL and LDL cholesterol in mice fed an atherogenic diet, and it contains a candidate gene, the sterol regulatory element binding protein-2. The locus on Chr 5 exhibited lod scores of 3.8 for total cholesterol and 4.1 for unesterified cholesterol in mice fed an atherogenic diet, and this locus has been observed in 2 previous studies. The locus on Chr 8 exhibited a lod score of 3.1 for unesterified cholesterol in mice fed a chow diet. This locus contains the lecithin-cholesterol acyltransferase gene, and decreased activity of the enzyme in the MRL strain suggests that this gene underlies the quantitative-trait locus. The locus on Chr 19 exhibited a lod score of 8.4 for HDL cholesterol and includes the Fas gene, which is mutated in MRL/lpr mice and is primarily responsible for the autoimmune phenotype in this cross. That the Fas gene is responsible for the HDL quantitative-trait loci is supported by the finding that autoantibody levels were strongly correlated with HDL cholesterol levels (rho=-0.37, P<0.0001) among the F2 mice. HDL cholesterol levels were in turn significantly associated with aortic fatty streak lesions among the F2 mice (rho=-0.17, P=0.006). Further, there was a threshold effect of autoantibody levels on the development of fatty streak lesions (rho=0.45, P=0.004 for 42 F2 mice with anti-dsDNA Ab over 0.5 OD). Our results support the concept that the high prevalence of coronary artery disease in systemic lupus erythematosus is due in part to a reduction of HDL cholesterol levels resulting from the autoimmune disease.

Effects of dietary n-6 and n-3 lipids on antioxidant defense system in livers of exercised rats

OBJECTIVE

The present study was designed to investigate the effects of dietary n-6 and n-3 lipids and exercise on the activities of hepatic antioxidant enzymes and microsomal lipid composition and peroxidation in Fischer-344 male rats.

METHODS

Weanling male Fischer-344 rats were fed ad libitum semipurified diets containing 10% corn oil (CO) or 10% fish oil (FO), with equal levels of antioxidants. After 2 months on the diets, weight-matched animals in each diet group were divided into sedentary (S) and exercised (Ex) groups, and the diets were continued. The animals in the exercise group were run on a treadmill 30 to 40 minutes to exhaustion 6 days/week for 2 months. At the end of 2 months, the rats were sacrificed and livers were collected; antioxidant enzymes were determined in the cytosol, fatty acid composition was analyzed in the microsomes, and vitamin E levels were analyzed in the sera.

RESULTS

The rats in the FO-S group exhibited significantly higher liver cytosolic catalase activity, while their superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were significantly lower compared to the CO-S group. The GSH-Px activity was significantly higher in the FO-Ex group compared to FO-S group. The source of dietary lipids significantly influenced the fatty acid composition of the total lipids in the microsomes. Feeding the FO-based diet significantly increased 18:0 and n-3 fatty acids incorporation into the microsomes (18:3, 20:5, 22:5, and 22:6), whereas ingestion of CO resulted in a significant increase in 14:0, 14:1, 18:1, and n-6 fatty acids (18:2 and 20:4). The serum vitamin E levels were significantly higher in the CO groups, and exercise had no effect on vitamin E levels. Exercise significantly decreased the generation of thiobarbituric acid reactive substances (TBARS) by liver microsomes. Consumption of FO, which is highly susceptible to oxidation, did not show any significant changes in membrane lipid peroxidation.

CONCLUSIONS

The present study suggests that feeding FO increases the activity of liver cytosolic catalase in FO-S rats and GSH-Px in FO-Ex rats. In addition, exercise significantly decreased the generation of TBARS by the liver microsomal lipids. Serum vitamin E levels were higher in the CO group and exercise did not alter vitamin E levels. This suggests that the amount of vitamin E included in the diets was possibly adequate to cope with the oxidative stress induced during exercise.

Alpha-glutathione transferases in HCV-related chronic hepatitis: a new predictive index of response to interferon therapy?

BACKGROUND/AIM

The aim of this study was to evaluate if plasma levels of alpha-glutathione-S-transferases (determined in basal conditions and monthly for 1 year during and 1 year after interferon therapy) could characterize patients who show only a primary response.

METHODS

We studied 48 patients with biopsy-proven, hepatitis C virus ribonucleic acid positive chronic hepatitis treated with interferon: 18 were "Sustained Responders", 12 "Relapsers" and 18 "Non-Responders".

RESULTS

Relapsers showed higher basal levels of alpha-glutathione-S-transferases, which remained higher than normal even when alanine aminotransferases normalized. No correlation was documented between alpha-glutathione-S-transferase levels and all other parameters examined (alanine aminotransferases, gamma-glutamyl-transpeptidase, viremia, and histological activity index).

CONCLUSIONS

These findings suggest that alpha-glutathione-S-transferase levels may be considered a predictive index of response to interferon therapy in chronic hepatitis C patients.

Modulation of antioxidant enzymes and programmed cell death by n-3 fatty acids

Studies from our laboratory indicate that n-3 (fish oil, FO) lipids at 10% (w/w) in a nutritionally adequate, semipurified diet, and supplemented with equal levels of antioxidants, extended the life span of lupus-prone (NZB/NZW)F1 (B/W) female mice as compared to n-6 (corn oil, CO) lipids. The early rise of autoimmune disease in CO-fed mice was closely linked to the loss of T-cell function. Both IL-2 production and IL-2 receptor expression were reduced due to the loss of naive T-cells and a rise in memory T-cells. Proliferative response to both mitogens and superantigens (staphylococcal enterotoxins A and B) was higher in FO-fed 6.5-mon-old mice. These changes paralleled decreased PGE2 production by splenic cells from FO-fed mice. Analysis of mRNA expression in different organs revealed differential effects of dietary lipids. In FO-fed mice, transforming growth factor beta 1 (TGF beta 1) expression was decreased in kidneys, but splenic tissues had higher expression of TGF beta mRNA. As TGF beta promotes programmed cell death (PCD), we studied the effects of CO and FO on PCD rates in lymphocytes. Both propidium iodide staining and DNA fragmentation were elevated in lymphocytes of FO-fed mice when compared to CO-fed mice of similar age. Also, increased PCD correlated closely with increased Fas gene expression. Thus, in addition to various other antiinflammatory effects, dietary FO appears to increase PCD and prevent accumulation of self-reactive immune cells in lymphoid organs. Further studies are required to dissect the pro- and antiinflammatory mechanisms associated with dietary n-3 and n-6 lipids in modulating autoimmune disorders or malignancy during aging.