Elevation of blood thioredoxin in hemodialysis patients with hepatitis C virus infection

Attenuation of Hyperoxic Lung Injury in Newborn Thioredoxin-1-Overexpressing Mice through the Suppression of Proinflammatory Cytokine mRNA Expression

The role of thioredoxin-1 (TRX), a small redox-active protein with antioxidant effects, during hyperoxic lung injury in newborns remains undetermined. We investigated TRX impact on hyperoxic lung injury in newborn TRX transgenic (TRX-Tg) and wildtype (WT) mice exposed to 21% or 95% O₂ for four days, after which some mice were allowed to recover in room air for up to 14 days. Lung morphology was assessed by hematoxylin/eosin and elastin staining, as well as immunostaining for macrophages. The gene expression levels of proinflammatory cytokines were evaluated using quantitative real-time polymerase chain reaction. During recovery from hyperoxia, TRX-Tg mice exhibited an improved mean linear intercept length and increased number of secondary septa in lungs compared with the WT mice. Neonatal hyperoxia enhanced the mRNA expression levels of proinflammatory cytokines in the lungs of both TRX-Tg and WT mice. However, interleukin-6, monocyte chemoattractant protein-1, and chemokine (C-X-C motif) ligand 2 mRNA expression levels were reduced in the lungs of TRX-Tg mice compared with the WT mice during recovery from hyperoxia. Furthermore, TRX-Tg mice exhibited reduced macrophage infiltration in lungs during recovery. These results suggest that in newborn mice TRX ameliorates hyperoxic lung injury during recovery likely through the suppression of proinflammatory cytokines.

Functional and biochemical responses of skeletal muscle following a moderate degree of systemic iron loading in mice

Excessive iron loading may cause skeletal muscle atrophy and weakness because of its free radical generating properties. To determine whether a clinically relevant degree of iron loading impairs skeletal muscle function, young male mice received injections of iron dextran (4 mg iron/200 µl) or 2 mM d-glucose (control) 5 days/week for 2 weeks ( n = 10/group). Systemic iron loading induced an approximate fourfold increase in the skeletal muscle nonheme iron concentration. Soleus specific tension (1, 30-250 Hz) was lower among iron-loaded animals compared with controls despite similar body mass and muscle mass. Soleus lipid peroxidation (4-hydroxynonenal adducts) and protein oxidation (protein carbonyls) levels were similar between groups. In gastrocnemius muscle, reduced glutathione (GSH) and glutathione peroxidase activity were similar but glutathione disulfide (GSSG) and the GSSG/GSH ratio were greater in iron-loaded muscle. A greater protein expression level of endogenous thiol antioxidant thioredoxin (TRX) was observed among iron-loaded muscle whereas its endogenous inhibitor thioredoxin-interacting protein (TXNip) and the TRX/TXNip ratio were similar. Glutaredoxin2, a thiol-disulfide oxidoreductase activated by GSSG-induced destabilization of its iron-sulfur [2Fe-2S] cluster, was lower following iron loading. Additionally, protein levels of α-actinin and αII-spectrin at 240 kDa were lower in the iron-loaded group. Ryanodine receptor stabilizing subunit calstabin1 was also lower following iron loading. In summary, the contractile dysfunction that resulted from moderate iron loading may be mediated by a disturbance in the muscle redox balance and from changes arising from an increased proteolytic response and aberrant sarcoplasmic reticulum Ca²⁺ release. NEW & NOTEWORTHY Although severe iron loading is known to cause muscle oxidative stress and dysfunction, the effects of a moderate degree of systemic iron loading on muscle contractile function and biochemical responses remain unclear. This study demonstrates that a pathophysiological elevation in the skeletal muscle iron load leads to force deficits that coincide with impaired redox status, structural integrity, and lower ryanodine receptor-associated calstabin1 in the absence of muscle mass changes or oxidative damage.

Malondialdehyde can predict survival in hemodialysis patients

Background and aims

Cardiovascular (CV) disease is the leading cause of morbidity and mortality in hemodialysis (HD) patients. Kidney disease is associated with increased oxidative stress (OS), a nontraditional CV risk factor. Few studies evaluate the effect of OS markers on CV events (CVE) and survival in HD patients. The aim of this study is to examine potential determinants of OS markers and their predictive role on survival and CV morbidity and mortality in HD patients during a long-term follow-up (108 months).

Methods

We conducted an analytical cross-sectional prospective observational study, carried on a cohort of randomly selected HD patients. We registered in 44 HD patients baseline characteristics, OS markers, mortality and CVE over a period of 108 months and we used statistical analysis (descriptive, Kaplan-Meier, univariate and multivariate Cox model) for interpretation.

Results

Bound malondialdehyde (bMDA) was positively correlated with serum calcium, protein carbonyls (PC) were inversely correlated with diastolic blood pressure (DBP) and directly correlated with ferritin, NO_x was directly correlated with ceruloplasmin) and serum albumin. Of the measured OS markers only bMDA was related to survival (HR=3.29 95% CI (1.28–8.44), p=0.01), and approached statistical significance in the effect on CV mortality (HR=2.85 95% CI (0.88–9.22), p=0.07). None of the measured OS markers was associated with CVE.

Conclusions

bMDA has a strong predictive value on survival in HD patients in a long-term follow-up (9 years). Its value is correlated with CV mortality but is not a predictor of CV events. Regular assessment of MDA in HD patients and the development of strategies aimed at reducing oxidative stress in these patients might be beneficial.

Diagnostic and prognostic value of serum thioredoxin and DJ-1 in non-small cell lung carcinoma patients

In response to reactive oxygen species (ROS), thioredoxin and DJ-1 are upregulated to counteract the detrimental effect of ROS under normal condition. However, cancer cells can take advantage of thioredoxin and DJ-1 against ROS-induced cell damage. In several human cancer types, thioredoxin and DJ-1 were found to be overexpressed. The present study aimed to explore the serum levels of thioredoxin and DJ-1 in non-small cell lung cancer (NSCLC) patients and its relationship to the diagnosis and prognosis of this particular malignancy. Sera from 134 NSCLC patients and 168 healthy controls were obtained. Using the enzyme-linked immunosorbent assay (ELISA) method, the levels of serum thioredoxin and DJ-1 were measured and correlated to the clinicopathological characteristics of NSCLC patients. The diagnostic and prognostic significance of the biomarkers were evaluated by using receiver operating curve (ROC), Kaplan-Meier curve, and log-rank analyses and the Cox proportional hazard model, respectively. Serum thioredoxin and DJ-1 levels were significantly higher in the NSCLC patients than that in the controls (23.5 ± 6.57 vs. 13.8 ± 2.49 and 7.11 ± 2.02 vs. 5.18 ± 1.26, respectively). NSCLC patients at later stage cancer showed significantly higher levels of serum thioredoxin and DJ-1 than those at the early stages (P < 0.01 and P < 0.05, respectively). Multivariate logistic regression analysis showed that high serum thioredoxin level was an independent risk factor for lymph nodal metastases and distant metastases (OR = 2.18, 95 % CI 1.26-3.41 and OR = 3.68, 95 % CI 2.16-5.33, respectively). In addition, an increase in the serum DJ-1 level was also identified as an independent risk factor for nodal metastases (OR = 1.37, 95 % CI 1.11-3.04). For predicting the development of NSCLC, ROC/area under the curve (AUC) analysis for thioredoxin indicated an AUC of 0.80 (sensitivity 0.62, specificity 0.92), and ROC/AUC analysis for DJ-1 showed an AUC of 0.78 (sensitivity 0.66, specificity 0.89). NSCLC patients with high serum thioredoxin and DJ-1 levels had lower survival rates than those with low levels, and multivariate analyses for overall survival revealed that high serum thioredoxin levels served as an independent prognostic factor for NSCLC (HR = 2.07, 95 % CI 1.19-3.48). Serum levels of thioredoxin and DJ-1 were significantly higher in NSCLC patients; therefore, these may be utilized as novel diagnostic and prognostic biomarkers for NSCLC.

Redox-active protein thioredoxin-1 administration ameliorates influenza A virus (H1N1)-induced acute lung injury in mice

OBJECTIVES

Influenza virus infections can cause severe acute lung injury leading to significant morbidity and mortality. Thioredoxin-1 is a redox-active defensive protein induced in response to stress conditions. Animal experiments have revealed that thioredoxin-1 has protective effects against various severe disorders. This study was undertaken to evaluate the protective effects of recombinant human thioredoxin-1 administration on influenza A virus (H1N1)-induced acute lung injury in mice.

DESIGN

Prospective animal trial.

SETTING

Research laboratory.

SUBJECTS

Nine-week-old male C57BL/6 mice inoculated with H1N1.

INTERVENTION

The mice were divided into a vehicle-treated group and recombinant human thioredoxin-1-treated group. For survival rate analysis, the vehicle or recombinant human thioredoxin-1 was administered intraperitoneally every second day from day -1 to day 13. For lung lavage and pathological analyses, vehicle or recombinant human thioredoxin-1 was administered intraperitoneally on days -1, 1, and 3.

MEASUREMENTS AND MAIN RESULTS

Lung lavage and pathological analyses were performed at 24, 72, and 120 hrs after inoculation. The recombinant human thioredoxin-1 treatment significantly improved the survival rate of H1N1-inoculated mice, although the treatment did not affect virus propagation in the lung. The treatment significantly attenuated the histological changes and neutrophil infiltration in the lung of H1N1-inoculated mice. The treatment significantly attenuated the production of tumor necrosis factor-α and chemokine (C-X-C motif) ligand 1 in the lung and oxidative stress enhancement, which were observed in H1N1-inoculated mice. H1N1 induced expressions of tumor necrosis factor-α and chemokine (C-X-C motif) ligand 1 in murine lung epithelial cells MLE-12, which were inhibited by the addition of recombinant human thioredoxin-1. The recombinant human thioredoxin-1 treatment started 30 mins after H1N1 inoculation also significantly improved the survival of the mice.

CONCLUSIONS

Exogenous administration of recombinant human thioredoxin-1 significantly improved the survival rate and attenuated lung histological changes in the murine model of influenza pneumonia. The protective mechanism of thioredoxin-1 might be explained by its potent antioxidative and anti-inflammatory actions. Consequently, recombinant human thioredoxin-1 might be a possible pharmacological strategy for severe influenza virus infection in humans.

Association of HCV core antigen seropositivity with long-term mortality in patients on regular hemodialysis

Anti-hepatitis C virus (HCV) antibody seropositivity is independently associated with poor prognosis in hemodialysis (HD) patients. However, anti-HCV antibody cannot distinguish between patients with active infection and those who have recovered from infection. We therefore aimed in this study to examine the association of HCV core antigen (HCVcAg) seropositivity with mortality in HD patients. We first measured serum HCVcAg using an immunoradiometric assay and anti-HCV antibody in 405 patients on regular HD, and followed them for 104 months. There were 82 patients (20.2%) who had been positive for anti-HCV antibodies; 57 (69.5%) of these were positive for HCVcAg. During the follow-up, 29 patients were excluded, so we tested the association of HCVcAg seropositivity with all-cause, cardiovascular (CV) and non-CV mortalities in 376 patients. A total of 209 patients (55.6%) had expired during the observational period, 92 out of them due to CV causes. After adjusting for comorbid parameters, HCVcAg was independently associated with overall mortality (HR 1.61, 95% CI 1.05–2.47, p < 0.05). HCV infection was significantly related to liver disease-related mortality. Past HCV infection also contributed to CV mortality (HR 2.63, 95% CI 1.27–5.45, p < 0.01). In contrast, anti-HCV antibody and HCVcAg seropositivities did not associate with infectious disease-related and cancer-related (expect for hepatocellular carcinoma) mortality. It follows from these findings that HCVcAg serology is associated with all-cause and CV mortality in HD patients.

The influence of hepatitis C infection activity on oxidative stress markers and erythropoietin requirement in hemodialysis patients

We sought to expose the possible effect of hepatitis C virus (HCV) infection on oxidative stress indicators, nutritional status, and erythropoietin (rHuEPO) requirements in maintenance hemodialysis (MHD) patients. A total of 111 MHD patients (69 males, 42 females; mean age 51.3 +/- 13.0 years; MHD duration 78.5 +/- 52.1 months) and 46 healthy controls were enrolled in the study. We excluded patients with hepatitis B infection or malignancy. Indicators for oxidative status were studied in plasma samples obtained at the beginning of a clinically stable MHD session. Measurements were performed for plasma superoxide dismutase, glutathione peroxidase (antioxidative agents), and malonyldialdehyde (MDA; oxidative agent) by spectrophotometric methods. All patients were analyzed for the presence of anti-HCV; positive patients were also evaluated for the presence of HCV RNA. MHD patients were divided into three groups according to HCV infection status: group I (anti-HCV-positive, HCV-RNA-negative; n = 22); group II (anti-HCV-positive, HCV-RNA-positive; n = 22), and group III (anti-HCV-negative; n = 67). According to the analyses, MHD patients showed higher plasma oxidative stress indicators and lower antioxidative indicator levels compared to controls (P < .0001). MHD patients also displayed lower albumin and higher C-reactive protein (CRP) levels compared to controls (P < .0001). Antioxidant levels were decreased significantly from group I to III (P < .0001). MDA levels significantly increased from group I to III (P < 0.01). HCV-RNA-positive patients showed lowest albumin and highest CRP levels and rHuEPO requirements. Although alanine transferase (ALT) levels were in the normal range, group II patients had significantly higher ALT levels than the other groups (P < .01). In conclusion, we observed negative effects of active HCV infection on oxidative stress and rHuEPO requirements. In contrast, we detected that clinically inactive HCV infection was associated with reduced oxidative stress and rHuEPO requirements compared with active HCV infection and HCV-negative patients.

Redox responses in patients with sepsis: high correlation of thioredoxin-1 and macrophage migration inhibitory factor plasma levels

Background. Redox active substances (e.g., Thioredoxin-1, Macrophage Migration Inhibitory Factor) seem to be central hubs in the septic inflammatory process. Materials and Methods. Blood samples from patients with severe sepsis or septic shock (n = 15) were collected at the time of sepsis diagnosis (t0), and 24 (t24) and 48 (t48) hours later; samples from healthy volunteers (n = 18) were collected once; samples from postoperative patients (n = 28) were taken one time immediately after surgery. In all patients, we measured plasma levels of IL-6, TRX1 and MIF. Results. The plasma levels of MIF and TRX1 were significantly elevated in patients with severe sepsis or septic shock. Furthermore, TRX1 and MIF plasma levels showed a strong correlation (t0: r_sp = 0.720, ρ = 0.698/t24: r_sp = 0.771, ρ = 0.949). Conclusions. Proinflammatory/~oxidative and anti-inflammatory/~oxidative agents show a high correlation in order to maintain a redox homeostasis and to avoid the harmful effects of an excessive inflammatory/oxidative response.

Serum C-reactive protein and thioredoxin levels in subjects with mildly reduced glomerular filtration rate

Background

Chronic kidney disease (CKD) is a newly recognized high-risk condition for cardiovascular disease (CVD), and previous studies reported the changes in inflammation and oxidative stress in advanced stages of CKD. We compared the levels of serum biomarkers for inflammation and oxidative stress between subjects with normal and mildly reduced glomerular filtration rate (GFR).

Methods

The subjects were 182 participants of a health check-up program including those with normal (≥ 90 mL/min/1.73 m², N = 79) and mildly reduced eGFR (60-89 mL/min/1.73 m², N = 103) which was calculated based on serum creatinine, age and sex. We excluded those with reduced eGFR < 60 mL/min/1.73 m². No one had proteinuria. We measured serum levels of C-reactive protein (CRP) and thioredoxin (TRX) as the markers of inflammation and oxidative stress, respectively.

Results

As compared with subjects with normal eGFR, those with mildly reduced eGFR had increased levels of both CRP and TRX. Also, eGFR was inversely correlated with these biomarkers. The associations of eGFR with these biomarkers remained significant after adjustment for age and sex. When adjustment was done for eight possible confounders, CRP showed significant association with systolic blood pressure, high density lipoprotein cholesterol (HDL-C) and non-HDL-C, whereas TRX was associated with sex significantly, and with eGFR and systolic blood pressure at borderline significance.

Conclusions

We showed the increased levels of CRP and TRX in subjects with mildly reduced eGFR. The eGFR-CRP link and the eGFR-TRX link appeared to be mediated, at least partly, by the alterations in blood pressure and plasma lipids in these subjects.

Thioredoxin in human and experimental sepsis

INTRODUCTION

Thioredoxin (TRX) is assumed to be beneficial in acute inflammatory diseases because of its potent antioxidant properties and an inhibitory effect on neutrophil evasion into sites of inflammation.

OBJECTIVE

To compare plasma levels of thioredoxin in septic patients and to investigate the role of thioredoxin in a polymicrobial septic mouse model.

DESIGN AND INTERVENTIONS

A combined single-center noninterventional clinical observation study and randomized controlled experimental investigation.

SETTING

Intensive care unit of a university hospital and laboratories of four university hospitals.

MEASUREMENTS AND MAIN RESULTS

To evaluate the role of TRX in sepsis, we measured TRX in plasma of septic patients and compared its levels in survivors and patients who did not survive sepsis. In addition, we examined the effect of neutralization of endogenous TRX as well as of treatment with recombinant TRX in a mouse peritonitis model of cecal ligation and puncture (CLP). We found that the serum plasma levels of TRX were significantly higher in patients with sepsis compared with healthy individuals. Furthermore, nonsurvivors showed even higher TRX levels than survivors of sepsis. The CLP septic mouse model revealed that neutralization of endogenous TRX impaired survival of septic mice, whereas treatment with recombinant TRX after CLP strongly enhanced the survival of mice.

CONCLUSIONS

Our results therefore demonstrate a critical role for TRX in the septic inflammatory response and suggest TRX as a potential therapeutic target for septic shock.

Thioredoxin-1 attenuates indomethacin-induced gastric mucosal injury in mice

Indomethacin is one of non-steroidal anti-inflammatory drugs that are commonly used clinically and often cause gastric mucosal injury as a side effect. Generation of reactive oxygen species (ROS) and activation of apoptotic signaling are involved in the pathogenesis of indomethacin-induced gastric mucosal injury. Thioredoxin-1 (Trx-1) is a small redox-active protein with anti-oxidative activity and redox-regulating functions. The aim of this study was to investigate the protective effect of Trx-1 against indomethacin-induced gastric mucosal injury. Trx-1 transgenic mice displayed less gastric mucosal damage than wild type (WT) C57BL/6 mice after intraperitoneal administration of indomethacin. Administration of recombinant human Trx-1 (rhTrx-1) or transfection of the Trx-1 gene reduced indomethacin-induced cytotoxicity in rat gastric epithelial RGM-1 cells. Pretreatment with rhTrx-1 suppressed indomethacininduced ROS production and downregulation of phosphorylated Akt in RGM-1 cells. Survivin, a member of inhibitors of apoptosis proteins family, was downregulated by indomethacin, which was suppressed in Trx-1 transgenic mice or by administration of rhTrx-1 in RGM-1 cells. Trx-1 inhibits indomethacin-induced apoptotic signaling and gastric ulcer formation, suggesting that it may have a preventive and therapeutic potential against indomethacin-induced gastric injury.

PON1 status in haemodialysis patients and the impact of hepatitis C infection

OBJECTIVES

Paraoxonase-1 (PON1) activity has been reported to decrease in both haemodialysis patients and patients with HCV infection. We aimed to investigate paraoxonase and arylesterase activities, and lipid hydroperoxide levels (LOOH) in haemodialysis patients with or without hepatitis C infection, and to find out whether PON1 activity is affected further by the presence of HCV infection in HD patients.

DESIGN AND METHODS

Twenty HCV (+) haemodialysis patients, 26 HCV (-) haemodialysis patients, and 26 controls were enrolled. Paraoxonase and arylesterase activities were measured spectrophotometrically. LOOH levels were measured by ferrous oxidation with xylenol orange assay.

RESULTS

Haemodialysis patients with or without HCV infection had lower paraoxonase and arylesterase activities than controls (all p<0.001), while higher LOOH levels (both p<0.001). Paraoxonase and arylesterase activities, and LOOH levels were comparable between haemodialysis patients with or without HCV infection (p>0.05). Significant inverse correlation was observed between paraoxonase or arylesterase activities, and LOOH levels (p<0.05, beta=-0.319 and p<0.05, beta=-0.348, respectively).

CONCLUSION

We concluded that PON1 activity significantly decreases in both haemodialysis patients with or without HCV infection. Nevertheless, PON1 activity is not affected further by the presence of HCV infection in haemodialysis patients.

Human thioredoxin-1 ameliorates experimental murine colitis in association with suppressed macrophage inhibitory factor production

BACKGROUND & AIMS

Thioredoxin-1 (TRX) is a small multifunctional protein with antioxidative and redox-regulating functions. In this study, we investigated the significance of TRX in patients with inflammatory bowel disease (IBD) and the ability and mechanism to ameliorate experimental colitis.

METHODS

Serum TRX and macrophage migration inhibitory factor (MIF) levels were measured in patients with IBD. The effects of TRX were evaluated in a dextran sulfate sodium (DSS)-induced colitis model by comparing TRX-overexpressing transgenic (TRX-TG) and control mice. We further evaluated the effect of recombinant human TRX (rhTRX) administration on DSS-induced colitis and colonic inflammation of interleukin (IL)-10 knockout (IL-10 KO) mice. Colonic inflammation was examined clinically and histologically. Proinflammatory cytokine levels were examined in colonic tissues, and MIF levels were measured in colonic tissues and sera in mice. The effect of TRX on MIF production was also analyzed in vitro.

RESULTS

Serum TRX and MIF levels were significantly higher in patients with IBD than normal controls, and TRX levels correlated with disease activity. TRX significantly ameliorated DSS-induced colitis and colonic inflammation of IL-10 KO mice. Increase of tumor necrosis factor-alpha and interferon-gamma in colonic tissues was significantly suppressed in TRX-TG mice compared with wild-type mice. MIF levels in colonic tissues and sera were significantly lower in TRX-TG mice than in wild-type mice, irrespective of DSS administration. Anti-TRX treatment exacerbated DSS-induced colitis. In vitro studies demonstrated that rhTRX suppressed MIF production in human monocyte cells.

CONCLUSIONS

TRX might have a potential as a novel therapeutic agent for the treatment of IBD.

Oxidative stress in hepatitis C infected end-stage renal disease subjects

BACKGROUND

Both uremia and hepatitis C infection is associated with increased oxidative stress. In the present study, we aimed to find out whether hepatitis C infection has any impact on oxidative stress in hemodialysis subjects.

METHODS

Sixteen hepatitis C (+) hemodialysis subjects, 24 hepatitis C negative hemodialysis subjects and 24 healthy subjects were included. Total antioxidant capacity, total peroxide level and oxidative stress index were determined in all subjects.

RESULTS

Total antioxidant capacity was significantly higher in controls than hemodialysis subjects with or without hepatitis C infection (all p < 0.05/3), while total peroxide level and oxidative stress index were significantly lower (all p < 0.05/3). Hepatitis C (-) hemodialysis subjects had higher total antioxidant capacity compared to hepatitis C (+) hemodialysis subjects (all p < 0.05/3). Total peroxide level and oxidative stress index was comparable between hemodialysis subjects with or without hepatitis C infection (p > 0.05/3).

CONCLUSION

Oxidative stress is increased in both hepatitis C (+) and hepatitis C (-) hemodialysis subjects. However, hepatitis C infection seems to not cause any additional increase in oxidative stress in hemodialysis subjects and it may be partly due to protective effect of dialysis treatment on hepatitis C infection.

Thioredoxin: friend or foe in human disease?

Thioredoxin (Trx), a small, ubiquitous thiol [sulfydryl (-SH)] protein, is one of the most important regulators of reduction-oxidation (redox) balance and, thus, redox-controlled cell functions. Although Trx was discovered 40 years ago in bacteria, the number and diversity of processes that Trx influences in human cells have only been appreciated recently. Processes influenced by Trx include the control of cellular redox balance, the promotion of cell growth, the inhibition of apoptosis and the modulation of inflammation. Not surprisingly, the role of Trx in a wide range of human diseases and conditions, including cancer, viral disease, ischaemia-reperfusion injury, cardiac conditions, aging, premature birth and newborn physiology, is subject to intense investigation. However, whether Trx contributes to or prevents the pathology of a particular condition is not always clear. In this article, we review the role of Trx in human disease and relate this to its redox activity and biological properties, and discuss the development and use of therapies that either inhibit or augment Trx activity.

Relationship between iron replacement and hepatic functions in hepatitis C virus-positive chronic haemodialysis patients

AIM

To investigate the effects of intravenous (i.v.) iron replacement on hepatic functions of hepatitis C virus (HCV)-positive haemodialysis patients.

METHODS

The present retrospective study included 89 HCV-positive and 57 HCV-negative haemodialysis patients. Alanine aminotransferase (ALT) levels were accepted as sustained high if the last three values were >/=20 U/L. All patients and the HCV-positive group were dichotomised into subgroups by the median for dialysis duration, the amounts of i.v. iron administered per year and totally.

RESULTS

Sustained high levels of ALT were significantly more frequent in the HCV-positive group (P < 0.001). In HCV-positive patients, the subgroup with ALT levels >/=20 U/L had significantly higher serum iron levels and mean amounts of i.v. iron administered per year and totally (P < 0.001) and the subgroup with the high mean total amount of i.v. iron had significantly higher serum ALT and iron levels (P < 0.001). Significant positive correlations were found in HCV-positive patients between ALT and serum iron levels (P < 0.001), as well as between ALT both with the mean amounts of i.v. iron administered per year (P = 0006) and totally (P = 0.015). Regression analysis showed that the main parameters effecting ALT were the serum iron level (P < 0.0001) and the mean amount of parenteral iron administered per year (P = 0.032).

CONCLUSION

We conclude that parenteral iron replacement might contribute to hepatocellular injury in HCV-positive haemodialysis patients.

The influence of hepatitis C and iron replacement therapy on plasma pentosidine levels in haemodialysis patients

BACKGROUND

Chronic liver disease and intravenous (i.v.) iron therapy can enhance oxidative stress. The aim of this study was to assess the influence of hepatitis C virus (HCV) and i.v. iron administration on oxidative stress in chronic haemodialysis (HD) patients.

METHODS

A total of 115 HD patients (47% males, age 47 +/- 13 years) were placed in two groups according to the presence (HCV(+)) or absence (HCV(-)) of serum antibodies against HCV. Plasma pentosidine, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6) and alanine aminotransferase (ALT) levels were measured. The patients were also analysed according to the tertiles of serum levels of ferritin: group 1 (ferritin <380 ng/ml), group 2 (ferritin 380-750 ng/ml) and group 3 (ferritin >750 ng/ml). The cumulative iron dose was recorded during 6 months prior to the study.

RESULTS

HCV(+) patients had significantly higher levels of plasma pentosidine and ALT than HCV(-) patients. Age, gender, serum albumin, IL-6 and hsCRP did not differ according to HCV serology. The levels of pentosidine were related to the ferritin levels and were significantly higher in group 3 compared with group 1. Moreover, the cumulative dose of iron was significantly higher in group 3 than in group 1. Plasma pentosidine showed a positive correlation with age, HCV and ferritin. In a stepwise backward multiple regression model, age and HCV were independent predictors of pentosidine levels.

CONCLUSION

HCV in HD patients is associated with increased pentosidine levels, possibly reflecting increased oxidative stress. The association between pentosidine and ferritin levels may suggest an impact of i.v. iron therapy.