Relationship between oxidative stress and antioxidant systems in the liver of patients with Wilson disease: hepatic manifestation in Wilson disease as a consequence of augmented oxidative stress

Deadly excess copper

Higher eukaryotes' life is impossible without copper redox activity and, literally, every breath we take biochemically demonstrates this. However, this dependence comes at a considerable price to ensure target-oriented copper action. Thereto its uptake, distribution but also excretion are executed by specialized proteins with high affinity for the transition metal. Consequently, malfunction of copper enzymes/transporters, as is the case in hereditary Wilson disease that affects the intracellular copper transporter ATP7B, comes with serious cellular damage. One hallmark of this disease is the progressive copper accumulation, primarily in liver but also brain that becomes deadly if left untreated. Such excess copper toxicity may also result from accidental ingestion or attempted suicide. Recent research has shed new light into the cell-toxic mechanisms and primarily affected intracellular targets and processes of such excess copper that may even be exploited with respect to cancer therapy. Moreover, new therapies are currently under development to fight against deadly toxic copper.

Insights into the Management of Chronic Hepatitis in Children-From Oxidative Stress to Antioxidant Therapy

Recent research has generated awareness of the existence of various pathophysiological pathways that contribute to the development of chronic diseases; thus, pro-oxidative factors have been accepted as significant contributors to the emergence of a wide range of diseases, from inflammatory to malignant. Redox homeostasis is especially crucial in liver pathology, as disturbances at this level have been linked to a variety of chronic diseases. Hepatitis is an umbrella term used to describe liver inflammation, which is the foundation of this disease regardless of its cause. Chronic hepatitis produces both oxidative stress generated by hepatocyte inflammation and viral inoculation. The majority of hepatitis in children is caused by a virus, and current studies reveal that 60-80% of cases become chronic, with many young patients still at risk of advancing liver damage. This review intends to emphasize the relevance of understanding these pathological redox pathways, as well as the need to update therapeutic strategies in chronic liver pathology, considering the beneficial effects of antioxidants.

Hepatic oxylipin profiles in mouse models of Wilson disease: New insights into early hepatic manifestations

Hepatic inflammation is commonly identified in Wilson disease (WD), a genetic disease of hepatic and brain copper accumulation. Copper accumulation is associated with increased oxidative stress and reactive oxygen species generation which may result in non-enzymatic oxidation of membrane-bound polyunsaturated fatty acids (PUFA). PUFA can be oxidized enzymatically via lipoxygenases (LOX), cyclooxygenases (COX), and cytochrome P450 monooxygenases (CYP). Products of PUFA oxidation are collectively known as oxylipins (OXL) and are bioactive lipids that modulate hepatic inflammation. We examined hepatic OXL profiles at early stages of WD in two mouse models, the toxic milk mouse from The Jackson Laboratory (tx-j) and the Atp7b knockout on a C57Bl/6 background (Atp7b-/-B6). Targeted lipidomic analysis performed by ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry showed that in both tx-j and Atp7b-/-B6 mice, hepatic OXL profiles were altered with higher thromboxane and prostaglandins levels. The levels of oxidative stress marker, 9-HETE were increased more markedly in tx-j mice. However, both genotypes showed upregulated transcript levels of many genes related to oxidative stress and inflammation. Both genotypes showed higher prostaglandins, thromboxin along with higher PUFA-derived alcohols, diols, and ketones with altered epoxides; the expression of Alox5 was upregulated and many CYP-related genes were dysregulated. Pathway analyses show dysregulation in arachidonic acid and linoleic acid metabolism characterizes mice with WD. Our findings indicate alterations in hepatic PUFA metabolism in early-stage WD and suggest the upregulation of both, non-enzymatic ROS-dependent and enzymatic PUFA oxidation, which could have implications for hepatic manifestations in WD and represent potential targets for future therapies.

Therapeutic implications of impaired nuclear receptor function and dysregulated metabolism in Wilson's disease

Copper is an essential trace element that is required for the activity of many enzymes and cellular processes, including energy homeostasis and neurotransmitter biosynthesis; however, excess copper accumulation results in significant cellular toxicity. The liver is the major organ for maintaining copper homeostasis. Inactivating mutations of the copper-transporting P-type ATPase, ATP7B, result in Wilson's disease, an autosomal recessive disorder that requires life-long medicinal therapy or liver transplantation. Current treatment protocols are limited to either sequestration of copper via chelation or reduction of copper absorption in the gut (zinc therapy). The goal of these strategies is to reduce free copper, redox stress, and cellular toxicity. Several lines of evidence in Wilson's disease animal models and patients have revealed altered hepatic metabolism and impaired hepatic nuclear receptor activity. Nuclear receptors are transcription factors that coordinate hepatic metabolism in normal and diseased livers, and several hepatic nuclear receptors have decreased activity in Wilson's disease and Atp7b-/- models. In this review, we summarize the basic physiology that underlies Wilson's disease pathology, Wilson's disease animal models, and the possibility of targeting nuclear receptor activity in Wilson's disease patients.

Oxidative Stress in Liver Pathophysiology and Disease

The liver is an organ that is particularly exposed to reactive oxygen species (ROS), which not only arise during metabolic functions but also during the biotransformation of xenobiotics. The disruption of redox balance causes oxidative stress, which affects liver function, modulates inflammatory pathways and contributes to disease. Thus, oxidative stress is implicated in acute liver injury and in the pathogenesis of prevalent infectious or metabolic chronic liver diseases such as viral hepatitis B or C, alcoholic fatty liver disease, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Moreover, oxidative stress plays a crucial role in liver disease progression to liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC). Herein, we provide an overview on the effects of oxidative stress on liver pathophysiology and the mechanisms by which oxidative stress promotes liver disease.

Optical coherence tomography in patients with Wilson's disease

BACKGROUND

Morphological changes of retina in patients with Wilson's disease (WD) can be found by optical coherence tomography (OCT), and such changes had significant differences between neurological forms (NWD) and hepatic forms (HWD) of WD. The aim of this study was to evaluate the relationship between morphological parameters of retina and brain magnetic resonance imaging (MRI) lesions, course of disease, type of disease, and sexuality in WD.

METHODS

A total of 46 WD patients and 40 health controls (HC) were recruited in this study. A total of 42 WD patients were divided into different groups according to clinical manifestations, course of disease, sexuality, and brain MRI lesions. We employed the Global Assessment Scale to assess neurological severity of WD patients. All WD patients and HC underwent retinal OCT to assess the thickness of inner limiting membrane (ILM) layer to retinal pigment epithelium layer and inner retina layer (ILM to inner plexiform layer, ILM-IPL).

RESULTS

Compared to HWD, NWD had thinner superior parafovea zone (108.07 ± 6.89 vs. 114.40 ± 5.54 μm, p < .01), temporal parafovea zone (97.17 ± 6.65 vs. 103.60 ± 4.53 μm, p < .01), inferior parafovea zone (108.114 ± 7.65 vs. 114.93 ± 5.84 μm, p < .01), and nasal parafovea zone (105.53 ± 8.01 vs. 112.10 ± 5.44 μm, p < .01) in inner retina layer. Course of disease influenced the retina thickness. Male patients had thinner inner retina layer compared to female patients.

CONCLUSION

Our results demonstrated that WD had thinner inner retina layer compared to HC, and NWD had thinner inner retina layer compared to HWD. We speculated the thickness of inner retina layer may be a potential useful biomarker for NWD.

Vascular Changes in Macula, Optic Disc, and Choroid in Wilson's Disease: A Cross-sectional Optical Coherence Tomography Angiography Study

PURPOSE

To evaluate the changes in the retinal and optic disc (OD) microcirculation in patients with Wilson's disease (WD) using optical coherence tomography angiography (OCTA).

MATERIALS AND METHODS

This cross-sectional comparative study included 35 eyes of 35 WD patients (study group) and 36 eyes of 36 healthy participants (control group). The patients with WD were divided into subgroups based on the presence of Kayser-Fleischer rings. All the participants underwent a comprehensive ophthalmological examination, including OCTA.

RESULTS

The inferior perifoveal deep capillary plexus vessel density (DCP-VD), inferior radial peripapillary capillary vessel density (RPC-VD), and inferior peripapillary retinal nerve fiber layer (PPRNFL) thickness were significantly lower in the WD group than in the healthy participants (p=0.041, p=0.043, and p=0.045, respectively). In addition, in the subgroup analysis, the superior RPC-VD and inferior PPRNFL were significantly lower in the subgroup with Kayser-Fleischer rings (p=0.013 and p=0.041, respectively).

CONCLUSION

We showed there to be changes in certain OCTA parameters in WD patients when compared with healthy controls. Thus, we hypothesized that OCTA could detect any retinal microvascular changes in WD patients without clinical evidence of retinal or OD involvement.

Antioxidant Capacity Is Decreased in Wilson's Disease and Correlates to Liver Function

The metabolic disorder Wilson's disease (WD) is caused by copper accumulation in the tissues due to a biallelic pathogenic mutation of the gene ATP7B, encoding intracellular copper transporter ATPase-7B. As copper is a redox active metal; aberrations in its homeostasis may create favourable conditions for superoxide-yielding redox cycling and oxidative damage to the cells. We tried to characterise antioxidant defence in WD patients and to evaluate whether it is related to liver function. The blood glutathione concentration, the activity of manganese-SOD (MnSOD), catalase (Cat), glutathione peroxidase, and glutathione S-transferase glutathione (GST), and serum antioxidant potential (AOP-450) were measured in WD treatment-naive patients and healthy controls and correlated with clinical data. The blood glutathione concentration, the activity of MnSOD, Cat, glutathione peroxidase, and GST and AOP-450 are significantly decreased in WD patients. There was a positive correlation of AOP-450 with AST. Moreover, the Cat and GST activity as well as AOP-450 strongly correlated with parameters of synthetic liver function. MnSOD activity correlated positively with ALT and AST.The blood glutathione concentration, the activity of MnSOD, Cat, glutathione peroxidase, and GST and AOP-450 are significantly decreased in WD patients. There was a positive correlation of AOP-450 with AST. Moreover, the Cat and GST activity as well as AOP-450 strongly correlated with parameters of synthetic liver function. MnSOD activity correlated positively with ALT and AST. Liver injury in course of WD is linked with decreased antioxidant capacity.

Oxysterol misbalance critically contributes to Wilson disease pathogenesis

Wilson disease (WD) is a metabolic disorder caused by inactivation of the copper-transporting ATPase 2 (ATP7B) and copper (Cu) overload in tissues. Excess Cu causes oxidative stress and pathologic changes with poorly understood mechanistic connections. In Atp7b^-/- mice with established liver disease, Cu overload activates the stress-sensitive transcription factor Nrf2 (nuclear factor erythroid-derived 2-like 2). Nrf2 targets, especially sulfotransferase 1e1 (Sult1e1), are strongly induced and cause elevation of sulfated sterols, whereas oxysterols are decreased. This sterol misbalance results in inhibition of the liver X receptor (LXR) and up-regulation of LXR targets associated with inflammatory responses. Pharmacological inhibition of Sult1e1 partially reverses oxysterol misbalance and LXR inhibition. Contribution of this pathway to advanced hepatic WD was demonstrated by treating mice with an LXR agonist. Treatment decreased inflammation by reducing expression of proinflammatory molecules, diminished fibrosis by down-regulating the noncanonical transforming growth factor-β signaling pathway, and improved liver morphology and function. Thus, the identified pathway is an important driver of WD.

Neuropsychiatric Manifestations of Wilson Disease: Correlation with MRI and Glutamate Excitotoxicity

This study aims to identify neuropsychiatric manifestations in neurological Wilson disease (NWD), and their correlation with MRI changes and glutamate excitotoxicity. Forty-three consecutive patients with NWD from a tertiary care teaching hospital were evaluated prospectively who fulfilled the inclusion criteria. The neuropsychiatric evaluation was done using Neuropsychiatric Inventory (NPI) battery that assesses 12 domains including delusion, hallucination, agitation/aggression, dysphoria/depression, anxiety, euphoria, apathy, disinhibition, irritability, aberrant motor activity, appetite change, and abnormal nighttime behavior. Cranial MRI was done using a 3 T machine, and locations of signal changes were noted including the total number of MRI lesions. Serum glutamate level was measured by a fluorescence microplate reader. Abnormal NPI in various domains and total NPI scores were correlated with MRI lesions, serum and urinary copper, and glutamate level. The median age of the patients was 16 years. Forty-one (48.8%) patients had cognitive impairment and 37 (86%) had movement disorder. Neurobehavioral abnormality was detected in all-commonest being agitation (90.7%) followed by appetite change (81.4%), elation (74.4%), irritability (69.8%), anxiety (67.4%), depression (65.1%), apathy (44.2%), night time abnormal behavior (32.6%), aberrant motor behavior (20.9%), delusions (16.3%), and hallucination (18.6%). The thalamic lesion was associated with depression, globus pallidus with depression and anxiety, caudate with anxiety and agitation, brainstem with irritability, and frontal cortex with apathy. Serum glutamate level was higher in NWD. NPI sum score correlated with MRI load and glutamate level. Varying severity of neurobehavioral abnormalities are common in the patients with NWD and correlate with the location of MRI lesion and glutamate level.

Optical coherence tomography in patients with Wilson's disease

OBJECTIVES

Wilson disease (WD) is an autosomal recessive disorder that leads to copper accumulation and deposition in different organs, frequently affecting visual pathways. Recent studies have detected morphological changes of the retina in patients with WD using optical coherence tomography (OCT). Measuring the thickness of the retinal nerve fibre layer (RNFL) with OCT provides an objective assessment of integrity and morphological abnormalities of the retina. The aim of this study was to evaluate the relationship between OCT parameters and form of the disease, therapy and symptoms duration, as well as severity of neurological impairment.

METHODS

The study comprised of 52 patients with WD and 52 healthy controls (HC). All the patients were on a regular and stable chelation therapy and/or zinc salts. Patients were divided into two groups, with neurological (NWD) or hepatic form of the disease (HWD). OCT was performed to assess the RNFL thickness.

RESULTS

The WD patients had significantly lower intraocular pressure in both eyes and lower RNFL thickness than the HC. There were no differences between NWD and HWD in any of the ophthalmologically tested parameters. No significant correlations were found between clinical features and retinal thickness parameters. Stratification of the cohort according to the disease duration showed that disease duration did not influence the RNFL thickness.

CONCLUSION

We found that involvement of the retina represented a subclinical finding in neurologically intact patients in the HWD group. Nevertheless, the value of OCT as a biomarker for the assessment of the clinical course and progression of WD still remains uncertain.

Characterizing effects of excess copper levels in a human astrocytic cell line with focus on oxidative stress markers

BACKGROUND

Being an essential trace element, copper is involved in diverse physiological processes. However, excess levels might lead to adverse effects. Disrupted copper homeostasis, particularly in the brain, has been associated with human diseases including the neurodegenerative disorders Wilson and Alzheimer's disease. In this context, astrocytes play an important role in the regulation of the copper homeostasis in the brain and likely in the prevention against neuronal toxicity, consequently pointing them out as a potential target for the neurotoxicity of copper. Major toxic mechanisms are discussed to be directed against mitochondria probably via oxidative stress. However, the toxic potential and mode of action of copper in astrocytes is poorly understood, so far.

METHODS

In this study, excess copper levels affecting human astrocytic cell model and their involvement in the neurotoxic mode of action of copper, as well as, effects on the homeostasis of other trace elements (Mn, Fe, Ca and Mg) were investigated.

RESULTS

Copper induced substantial cytotoxic effects in the human astrocytic cell line following 48 h incubation (EC₃₀: 250 μM) and affected mitochondrial function, as observed via reduction of mitochondrial membrane potential and increased ROS production, likely originating from mitochondria. Moreover, cellular GSH metabolism was altered as well. Interestingly, not only cellular copper levels were affected, but also the homeostasis of other elements (Ca, Fe and Mn) were disrupted.

CONCLUSION

One potential toxic mode of action of copper seems to be effects on the mitochondria along with induction of oxidative stress in the human astrocytic cell model. Moreover, excess copper levels seem to interact with the homeostasis of other essential elements such as Ca, Fe and Mn. Disrupted element homeostasis might also contribute to the induction of oxidative stress, likely involved in the onset and progression of neurodegenerative disorders. These insights in the toxic mechanisms will help to develop ideas and approaches for therapeutic strategies against copper-mediated diseases.

Reproductive function of long-term treated patients with hepatic onset of Wilson's disease: a prospective study

RESEARCH QUESTION

Wilson's disease (WD) is a disorder of copper metabolism that can cause hormonal alterations. The impact of WD and its therapies on fertility is not well defined. The aim of this study was to evaluate ovarian reserve and sperm parameters in long-term treated WD patients with hepatic onset.

DESIGN

WD patients with hepatic onset treated for at least 5 years were compared with healthy controls. Men underwent spermiogram and sperm DNA fragmentation (SDF) analysis. Women were tested for serum FSH, anti-Müllerian hormone (AMH) and sonographic antral follicle count (AFC) in the early follicular phase. Ovulation was monitored with ultrasound and progesterone serum concentrations in the luteal phase.

RESULTS

The WD group included 26 patients (12 males), the control group 19 subjects (9 males). All patients apart from four (one male) were responders to WD treatment. Sperm count and morphology were comparable between cases and controls. Sperm motility (total and after 1 h) was significantly lower in cases (44.78 ± 21.65%; 47.85 ± 21.52%) than controls (61.88 ± 11.03; 69.44 ± 11.02%, P = 0.03 and 0.01, respectively). The only non-responder had severe oligo-astheno-teratozoospermia. SDF values were normal in cases and controls. AMH, AFC and FSH did not differ between cases and controls. LH was significantly lower in cases (3.36 ± 1.65 mIU/ml) than controls (6.25 ± 1.03 mIU/ml, P < 0.0001). A non-responder woman who developed neurological signs had a 7-year history of infertility.

CONCLUSIONS

WD patients with hepatic onset, diagnosed early and treated, have no impairment in fertility potential even if males show reduced sperm motility and females lower LH values. Only patients with poor disease control have some evidence of impaired fertility.

Copper interferes with selenoprotein synthesis and activity

Selenium and copper are essential trace elements for humans, needed for the biosynthesis of enzymes contributing to redox homeostasis and redox-dependent signaling pathways. Selenium is incorporated as selenocysteine into the active site of redox-relevant selenoproteins including glutathione peroxidases (GPX) and thioredoxin reductases (TXNRD). Copper-dependent enzymes mediate electron transfer and other redox reactions. As selenoprotein expression can be modulated e.g. by H2O2, we tested the hypothesis that copper status affects selenoprotein expression. To this end, hepatocarcinoma HepG2 cells and mice were exposed to a variable copper and selenium supply in a physiologically relevant concentration range, and transcript and protein expression as well as GPX and TXNRD activities were compared. Copper suppressed selenoprotein mRNA levels of GPX1 and SELENOW, downregulated GPX and TXNRD activities and decreased UGA recoding efficiency in reporter cells. The interfering effects were successfully suppressed by applying the copper chelators bathocuproinedisulfonic acid or tetrathiomolybdate. In mice, a decreased copper supply moderately decreased the copper status and negatively affected hepatic TXNRD activity. We conclude that there is a hitherto unknown interrelationship between copper and selenium status, and that copper negatively affects selenoprotein expression and activity most probably via limiting UGA recoding. This interference may be of physiological relevance during aging, where a particular shift in the selenium to copper ratio has been reported. An increased concentration of copper in face of a downregulated selenoprotein expression may synergize and negatively affect the cellular redox homeostasis contributing to disease processes.

Metabolic dysregulation in the Atp7b-/- Wilson's disease mouse model

Inactivating mutations in the copper transporter Atp7b result in Wilson's disease. The Atp7b-/- mouse develops hallmarks of Wilson's disease. The activity of several nuclear receptors decreased in Atp7b-/- mice, and nuclear receptors are critical for maintaining metabolic homeostasis. Therefore, we anticipated that Atp7b-/- mice would exhibit altered progression of diet-induced obesity, fatty liver, and insulin resistance. Following 10 wk on a chow or Western-type diet (40% kcal fat), parameters of glucose and lipid homeostasis were measured. Hepatic metabolites were measured by liquid chromatography-mass spectrometry and correlated with transcriptomic data. Atp7b-/- mice fed a chow diet presented with blunted body-weight gain over time, had lower fat mass, and were more glucose tolerant than wild type (WT) littermate controls. On the Western diet, Atp7b-/- mice exhibited reduced body weight, adiposity, and hepatic steatosis compared with WT controls. Atp7b-/- mice fed either diet were more insulin sensitive than WT controls; however, fasted Atp7b-/- mice exhibited hypoglycemia after administration of insulin due to an impaired glucose counterregulatory response, as evidenced by reduced hepatic glucose production. Coupling gene expression with metabolomic analyses, we observed striking changes in hepatic metabolic profiles in Atp7b-/- mice, including increases in glycolytic intermediates and components of the tricarboxylic acid cycle. In addition, the active phosphorylated form of AMP kinase was significantly increased in Atp7b-/- mice relative to WT controls. Alterations in hepatic metabolic profiles and nuclear receptor signaling were associated with improved glucose tolerance and insulin sensitivity as well as with impaired fasting glucose production in Atp7b-/- mice.

Movement Disorder in Copper Toxicity Rat Model: Role of Inflammation and Apoptosis in the Corpus Striatum

The pattern of copper (Cu) toxicity in humans is similar to Wilson disease, and they have movement disorders and frequent involvement of corpus striatum. The extent of cell deaths in corpus striatum may be the basis of movement disorder and may be confirmed in the experimental study. To evaluate the extent of apoptosis and glial activation in corpus striatum following Cu toxicity in a rat model, and correlate these with spontaneous locomotor activity (SLA), six male Wistar rats were fed normal saline (group I) and another six were fed copper sulfate 100 mg/kgBWt/daily orally (group II). At 1 month, neurobehavioral studies including SLA, rotarod, and grip strength were done. Corpus striatum was removed and was subjected to glial fibrillary acidic protein (GFAP) and caspase-3 immunohistochemistry. The concentration of tissue Cu, total antioxidant capacity (TAC), glutathione (GSH), malondialdehyde (MDA), and glutamate were measured. Group II rats had higher expression of caspase-3 (Mean ± SEM 32.67 ± 1.46 vs 4.47 ± 1.08; p < 0.01) and GFAP (41.81 ± 1.68 vs 31.82 ± 1.27; p < 0.01) compared with group I. Neurobehavioral studies revealed reduced total distance traveled, time moving, the number of rearing, latency to fall on the rotarod, grip strength, and increased resting time compared with group I. The expression of GFAP and caspase-3 correlated with SLA parameters, tissue Cu, GSH, MDA, TAC, and glutamate levels. The impaired locomotor activity in Cu toxicity rats is due to apoptotic and inflammatory-mediated cell death in the corpus striatum because of Cu-mediated oxidative stress and excitotoxicity.

The effects of iron and zinc status on prognosis in pediatric Wilson's disease

OBJECTIVES

Wilson's disease (WD) is a metabolic disorder leading to hepatic and extrahepatic copper deposition. Several studies have reported that besides copper (Cu), iron (Fe) and zinc (Zn) are also accumulated at varying levels in various tissues in WD. However, there is not an adequate number of studies investigating the effects of Fe and Zn status on WD presentation and prognosis. We aimed to evaluate serum levels of ferritin (SFr), copper (SCu), and zinc (SZn) in WD and determine their role in disease presentation and prognosis.

MATERIALS-METHOD

We retrospectively reviewed the medical records of 97 pediatric patients with WD who were diagnosed and followed at İnönü University Pediatric Gastroenterology, Hepatology and Nutrition Department between January 2006 and May 2017. Serum Cu and Zn levels were analyzed by using flame atomic absorption spectrophotometer. Ferritin was analyzed by chemiluminescence immunoassay method.

RESULTS

Analysis of serum levels of the elements according to the type of presentation, there was no significant difference between the groups for ceruloplasmin. However, SCU, FSCu, SFr and 24 h urinary copper levels were significantly higher (p = 0.002, p = 0.003, p = 0.023 and p < 0.001, respectively) and SZn and CSZn levels were significantly lower (fulminant WD). p < 0.001, p < 0.001). There was a positive correlation between SFr, SCu serum levels and mortality scores (respectively, r: 0.501, 0.564 for PELD, r:0.490, 0.504 for MELD, r: 0.345, 0.374 for Dhwan), and a negative correlation between SZn level and mortality scores. (r:-0.650 for PELD, r:-0.703 for MELD, r:-0.642 for Dhwan) We used the ROC curves to determine the worst prognosis for fulminant Wilson disease. According to these limit values, we found that the sensitivity and specificity of FWD development was significantly higher. (for SZn sensitivity of 91.5%, a specificity of 100%, p=<0,001, for SCu predicted FWD development with a sensitivity of 100%, a specificity of 73.7%, p=<0,001, for SFr predicted FWD development with a sensitivity of 92.9%, a specificity of 66.2%, p < 0,001) CONCLUSION: Our study suggests that SFr, SCu, SZn levels might have prognostic importance for WD.

ACVIM consensus statement on the diagnosis and treatment of chronic hepatitis in dogs

This consensus statement on chronic hepatitis (CH) in dogs is based on the expert opinion of 7 specialists with extensive experience in diagnosing, treating, and conducting clinical research in hepatology in dogs. It was generated from expert opinion and information gathered from searching of PubMed for manuscripts on CH, the Veterinary Information Network for abstracts and conference proceeding from annual meetings of the American College of Veterinary Medicine and the European College of Veterinary Medicine, and selected manuscripts from the human literature on CH. The panel recognizes that the diagnosis and treatment of CH in the dog is a complex process that requires integration of clinical presentation with clinical pathology, diagnostic imaging, and hepatic biopsy. Essential to this process is an index of suspicion for CH, knowledge of how to best collect tissue samples, access to a pathologist with experience in assessing hepatic histopathology, knowledge of reasonable medical interventions, and a strategy for monitoring treatment response and complications.

HSD17B13 truncated variant is associated with a mild hepatic phenotype in Wilson's Disease

HSD17B13 encodes hydroxysteroid 17-β dehydrogenase 13, a novel liver lipid-droplet associated protein that is involved in the regulation of lipid biosynthetic processes. A protein-truncating HSD17B13 variant (rs72613567) was shown to protect individuals from alcoholic and non-alcoholic liver disease. Since steatosis is a common feature in Wilson's disease (WD), we aimed to assess whether the HSD17B13 variant modulates the phenotypic presentation and progression of WD.

METHODS

The HSD17B13:TA (rs72613567) variant was determined by allelic discrimination real-time PCR in 586 patients. The HSD17B13 genotype was correlated with the phenotypic presentation. The age of onset and the type of symptoms at presentation were used as markers of the WD phenotype.

RESULTS

The overall HSD17B13:TA allele frequency in patients with WD was 23.3% (273/1,172), not significantly different from the reported minor allele frequency. There was a significantly lower HSD17B13:TA allele frequency in patients with fulminant WD compared to all other phenotypic WD groups (11.0% vs. 24.0%, p < 0.01). Among the patients with fulminant WD there was a trend for a gender effect; none of the male patients carried the HSD17B13:TA allele. HSD17B13:TA allele frequency was more common in patients with minimal or no fibrosis (49 [31.1%] had simple steatosis and 20 minimal changes at biopsy) than in patients with cirrhosis or advanced fibrosis (22.3%, p = 0.025).

CONCLUSIONS

The HSD17B13:TA allele modulates the phenotype and outcome of WD. This allele likely ameliorates hepatic fibrosis and reduces the transition from copper induced hemolysis to fulminant disease in patients with WD.

LAY SUMMARY

Wilson's disease is a hereditary disease caused by accumulation of copper in the liver and other tissues. It presents with a variety of clinical symptoms. In this study we explored the role of a recently described gene mutation (HSD17B13:TA) which apparently protects the liver against toxins like alcohol. The results indicate that this mutation plays a role in the evolution of liver disease. Patients with Wilson's disease who carry this mutation are more likely to have mild disease, while the absence of the mutation is associated with the most severe form - fulminant Wilson's disease.

Metabolomics profiles of patients with Wilson disease reveal a distinct metabolic signature

INTRODUCTION

Wilson disease (WD) is characterized by excessive intracellular copper accumulation in liver and brain due to defective copper biliary excretion. With highly varied phenotypes and a lack of biomarkers for the different clinical manifestations, diagnosis and treatment can be difficult.

OBJECTIVE

The aim of the present study was to analyze serum metabolomics profiles of patients with Wilson disease compared to healthy subjects, with the goal of identifying differentially abundant metabolites as potential biomarkers for this condition.

METHODS

Hydrophilic interaction liquid chromatography-quadrupole time of flight mass spectrometry was used to evaluate the untargeted serum metabolome of 61 patients with WD (26 hepatic and 25 neurologic subtypes, 10 preclinical) compared to 15 healthy subjects. We conducted analysis of covariance with potential confounders (body mass index, age, sex) as covariates and partial least-squares analysis.

RESULTS

After adjusting for clinical covariates and multiple testing, we identified 99 significantly different metabolites (FDR < 0.05) between WD and healthy subjects. Subtype comparisons also revealed significantly different metabolites compared to healthy subjects: WD hepatic subtype (67), WD neurologic subtype (57), WD hepatic-neurologic combined (77), and preclinical (36). Pathway analysis revealed these metabolites are involved in amino acid metabolism, the tricarboxylic acid cycle, choline metabolism, and oxidative stress.

CONCLUSIONS

Patients with WD are characterized by a distinct metabolomics profile providing new insights into WD pathogenesis and identifying new potential diagnostic biomarkers.

Epigenetic changes of the thioredoxin system in the tx-j mouse model and in patients with Wilson disease

Wilson disease (WD) is caused by mutations in the copper transporter ATP7B, leading to copper accumulation in the liver and brain. Excess copper inhibits S-adenosyl-L-homocysteine hydrolase, leading to variable WD phenotypes from widespread alterations in DNA methylation and gene expression. Previously, we demonstrated that maternal choline supplementation in the Jackson toxic milk (tx-j) mouse model of WD corrected higher thioredoxin 1 (TNX1) transcript levels in fetal liver. Here, we investigated the effect of maternal choline supplementation on genome-wide DNA methylation patterns in tx-j fetal liver by whole-genome bisulfite sequencing (WGBS). Tx-j Atp7b genotype-dependent differences in DNA methylation were corrected by choline for genes including, but not exclusive to, oxidative stress pathways. To examine phenotypic effects of postnatal choline supplementation, tx-j mice were randomized to one of six treatment groups: with or without maternal and/or continued choline supplementation, and with or without copper chelation with penicillamine (PCA) treatment. Hepatic transcript levels of TXN1 and peroxiredoxin 1 (Prdx1) were significantly higher in mice receiving maternal and continued choline with or without PCA treatment compared to untreated mice. A WGBS comparison of human WD liver and tx-j mouse liver demonstrated a significant overlap of differentially methylated genes associated with ATP7B deficiency. Further, eight genes in the thioredoxin (TXN) pathway were differentially methylated in human WD liver samples. In summary, Atp7b deficiency and choline supplementation have a genome-wide impact, including on TXN system-related genes, in tx-j mice. These findings could explain the variability of WD phenotype and suggest new complementary treatment options for WD.

Value of Serum Zinc in Diagnosing and Assessing Severity of Liver Disease in Children With Wilson Disease

OBJECTIVES

Wilson disease (WD) is a rare inborn error of copper metabolism with diverse manifestations. There has been no study of zinc (Zn), the copper's antagonist, in WD diagnosis and severity so far. Our aims were to evaluate serum Zn in WD and its correlation with the disease severity score (revised WD index). Although the ATP7B mutation analysis is highly accurate for WD diagnosis, it may not be readily available in a resource-limiting setting. We proposed a disease diagnostic score (Proposed WD diagnostic score) which incorporates serum Zn.

METHODS

Medical records of WD and non-WD children seen at King's College Hospital from 2005 to 2015 were reviewed for the selected parameters using the Proposed WD diagnostic score. Available serum Zn data in WD children before disease diagnosis and the calculated severity score were statistically analyzed. Diagnostic values of the Proposed WD diagnostic score were evaluated.

RESULTS

Serum Zn level was significantly lower in 8 WD-acute liver failure (ALF) (5.8 [4.1-8.3] μmol/L) compared to 18 WD-non-ALF (13.5 [6.1-22.2] μmol/L) and 9 ALF from indeterminate cause (9.8 [7.0-12.1] μmol/L) (P < 0.001). Serum Zn significantly correlated with the revised WD index (r = -0.554, P = 0.004). The Proposed WD diagnostic score that included serum Zn level as 1 of the parameters had sensitivity and specificity of 87% and 99.2%, respectively.

CONCLUSIONS

Serum Zn is a novel parameter for diagnosis and correlates with severity of WD. The Proposed WD diagnostic score is useful while awaiting ATP7B mutation analysis.

Mitochondria and Reactive Oxygen Species in Aging and Age-Related Diseases

Aging has been linked to several degenerative processes that, through the accumulation of molecular and cellular damage, can progressively lead to cell dysfunction and organ failure. Human aging is linked with a higher risk for individuals to develop cancer, neurodegenerative, cardiovascular, and metabolic disorders. The understanding of the molecular basis of aging and associated diseases has been one major challenge of scientific research over the last decades. Mitochondria, the center of oxidative metabolism and principal site of reactive oxygen species (ROS) production, are crucial both in health and in pathogenesis of many diseases. Redox signaling is important for the modulation of cell functions and several studies indicate a dual role for ROS in cell physiology. In fact, high concentrations of ROS are pathogenic and can cause severe damage to cell and organelle membranes, DNA, and proteins. On the other hand, moderate amounts of ROS are essential for the maintenance of several biological processes, including gene expression. In this review, we provide an update regarding the key roles of ROS-mitochondria cross talk in different fundamental physiological or pathological situations accompanying aging and highlighting that mitochondrial ROS may be a decisive target in clinical practice.

Cellular copper homeostasis: current concepts on its interplay with glutathione homeostasis and its implication in physiology and human diseases

Copper is a trace element essential for almost all living organisms. But the level of intracellular copper needs to be tightly regulated. Dysregulation of cellular copper homeostasis leading to various diseases demonstrates the importance of this tight regulation. Copper homeostasis is regulated not only within the cell but also within individual intracellular compartments. Inactivation of export machinery results in excess copper being redistributed into various intracellular organelles. Recent evidence suggests the involvement of glutathione in playing an important role in regulating copper entry and intracellular copper homeostasis. Therefore interplay of both homeostases might play an important role within the cell. Similar to copper, glutathione balance is tightly regulated within individual cellular compartments. This review explores the existing literature on the role of glutathione in regulating cellular copper homeostasis. On the one hand, interplay of glutathione and copper homeostasis performs an important role in normal physiological processes, for example neuronal differentiation. On the other hand, perturbation of the interplay might play a key role in the pathogenesis of copper homeostasis disorders.

The adjuvant value of Herba Cistanches when used in combination with statin in murine models

Statins are well known to have muscle toxicity problem. Herba Cistanches (HC) is a Chinese herb traditionally used for pain in the loins and knees. Our previous in vitro study suggested that it could protect against statin-induced muscle toxicity. However, its in vivo protective effect has never been investigated. The objective of this study was to determine if the aqueous extract of HC (HCE) could prevent simvastatin-induced muscle toxicity in rats, and whether HCE could also exert beneficial effects on reducing high-fat diet-induced hypercholesterolemia and elevated liver cholesterol, thereby reducing the dose of simvastatin when used in combined therapy. From our results, HCE significantly restored simvastatin-induced reduction in muscle weights and reduced elevated plasma creatine kinase in rats. HCE also improved simvastatin-induced reduction in muscle glutathione levels, muscle mitochondrial membrane potential, and reduced simvastatin-induced muscle inflammation. Furthermore, HCE could exert reduction on liver weight, total liver lipid levels and plasma lipid levels in high-fat-fed mice. In conclusion, our study provided in vivo evidence that HCE has potential protective effect on simvastatin-induced toxicity in muscles, and also beneficial effects on diet-induced non-alcoholic fatty liver and hyperlipidemia when being used alone or in combination with simvastatin at a reduced dose.

Effects of ciprofloxacin on fetal rat liver during pregnancy and protective effects of quercetin

Urinary tract infections are common in pregnant women and ciprofloxacin frequently is used as a broad spectrum antibiotic. It has been suggested that ciprofloxacin causes liver damage in fetuses. Quercetin is a flavonoid with antioxidant properties. We investigated the efficacy of quercetin treatment for preventing fetal liver damage caused by ciprofloxacin. Pregnant rats were divided into four groups: untreated control group (C), 20 mg/kg quercetin for 21 days group (Q), 20 mg/kg twice/day ciprofloxacin for 10 days group (CP), and 20 mg/kg, ciprofloxacin + quercetin for 21 days group (CP + Q). Fetal livers were removed on day 21 of gestation to measure antioxidants and for histological observation. Malondialdehyde (MDA) and glutathione (GSH) levels, and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were measured in tissue samples. GSH-Px, SOD and CAT activities were significantly lower in the CP group compared to group C. A significant increase in MDA was observed in the CP group compared to group C. There was no significant difference in GSH levels in any group. MDA levels were lower and CAT, SOD and GSH-Px enzyme activities were higher in the CP + Q group compared to group CP. Liver samples of the CP group exhibited central vein dilation, portal vein congestion, pyknotic nuclei and cytoplasmic vacuolization in some hepatocytes. Histological changes were less prominent in the rats treated with quercetin. Use of ciprofloxacin during pregnancy caused oxidative damage in fetal liver tissue. Oxidative stress was ameliorated by quercetin. Quercetin supports the antioxidant defense mechanism and it is beneficial for treating fetal liver damage caused by ciprofloxacin.

Ameliorative Effect of Curcumin-Encapsulated Hyaluronic Acid-PLA Nanoparticles on Thioacetamide-Induced Murine Hepatic Fibrosis

In this study, we developed curcumin-encapsulated hyaluronic acid–polylactide nanoparticles (CEHPNPs) to be used for liver fibrosis amelioration. CD44, the hyaluronic acid (HA) receptor, is upregulated on the surface of cancer cells and on activated hepatic stellate cells (aHSCs) rather than normal cells. CEHPNPs could bind to CD44 and be internalized effectively through endocytosis to release curcumin, a poor water-soluble liver protective agent. Thus, CEHPNPs were potentially not only improving drug efficiency, but also targeting aHSCs. HA and polylactide (PLA) were crosslinked by adipic acid dihydrazide (ADH). The synthesis of HA–PLA was monitored by Fourier-transform infrared (FTIR) and Nuclear Magnetic Resonance (NMR). The average particle size was approximately 60–70 nm as determined by dynamic light scattering (DLS) and scanning electron microscope (SEM). Zeta potential was around −30 mV, which suggested a good stability of the particles. This drug delivery system induced significant aHSC cell death without affecting quiescent HSCs, hepatic epithelial, and parenchymal cells. This system reduced drug dosage without sacrificing therapeutic efficacy. The cytotoxicity IC₅₀ (inhibitory concentration at 50%) value of CEHPNPs was approximately 1/30 to that of the free drug treated group in vitro. Additionally, the therapeutic effects of CEHPNPs were as effective as the group treated with the same curcumin dose intensity in vivo. CEHPNPs significantly reduced serum aspartate transaminase/alanine transaminase (ALT/AST) significantly, and attenuated tissue collagen production and cell proliferation as revealed by liver biopsy. Conclusively, the advantages of superior biosafety and satisfactory therapeutic effect mean that CEHPNPs hold great potential for treating hepatic fibrosis.

Polysorbate-80-coated, polymeric curcumin nanoparticles for in vivo anti-depressant activity across BBB and envisaged biomolecular mechanism of action through a proposed pharmacophore model

Depression is a modern world epidemic. Its main causative factor is oxidative stress, as reported in study subjects. Natural products are yet to show significant therapeutic effects in comparison with synthetic drugs. Current study deals with the preparation of brain-targeted polysorbate-80-coated curcumin PLGA nanoparticles (PS-80-CUR-NP), and their characterisation via Spectral and optical methods. PS-80-CUR-NP were evaluated against the oxidative stress-mediated depressant (OSMD) activity via Force despair, Tail suspension tests and stress biomarker assay (SOD and catalase activity). A significant reduction in immobility (p < 0.01) in force despair and tail suspension test and a significant increase (p < 0.001 and p < 0.01) in SOD and catalase activity was found and compared with stress control, which confirmed the OSMD activity of PS-80-CUR-NP at 5 mg equivalent dose. Further, AUC_(0.5-15 h) curve of brain homogenates estimated the curcumin concentration of 1.73 ng/g C_max at T_max 3 h via HPLC technique.

Copper induces hepatocyte injury due to the endoplasmic reticulum stress in cultured cells and patients with Wilson disease

Copper is an essential trace element, however, excess copper is harmful to human health. Excess copper-derived oxidants contribute to the progression of Wilson disease, and oxidative stress induces accumulation of abnormal proteins. It is known that the endoplasmic reticulum (ER) plays an important role in proper protein folding, and that accumulation of misfolded proteins disturbs ER homeostasis resulting in ER stress. However, copper-induced ER homeostasis disturbance has not been fully clarified. We treated human hepatoma cell line (Huh7) and immortalized-human hepatocyte cell line (OUMS29) with copper and chemical chaperones, including 4-phenylbutyrate and ursodeoxycholic acid. We examined copper-induced oxidative stress, ER stress and apoptosis by immunofluorescence microscopy and immunoblot analyses. Furthermore, we examined the effects of copper on carcinogenesis. Excess copper induced not only oxidative stress but also ER stress. Furthermore, excess copper induced DNA damage and reduced cell proliferation. Chemical chaperones reduced this copper-induced hepatotoxicity. Excess copper induced hepatotoxicity via ER stress. We also confirmed the abnormality of ultra-structure of the ER of hepatocytes in patients with Wilson disease. These findings show that ER stress plays a pivotal role in Wilson disease, and suggests that chemical chaperones may have beneficial effects in the treatment of Wilson disease.

Current Drug Managements of Wilson's Disease: From West to East

Wilson's disease (WD), also called hepatolenticular degeneration, is an autosomal recessive inheritance disorder of copper metabolism characterized by the multiple mutations in the ATP-ase 7B gene of chromosome 13q. About half of the WD patients have neurological or psychiatric symptoms. As WD is a kind of medicable or nearly curable neurodegenerative disease in the field of medicine, early consideration/examination and without delay/ life-long treatment usually lead to better prognoses. The drugs, also named as anticopper agents, are commonly used in clinics including D-penicillamine, trientine, sodium dimercaptosuccinate, dimercaptosuccinic acid, zinc and tetrathiomolybdate. This provides detailed reviews about these medicines.

A Study on Apoptosis and Anti-apoptotic Status in Wilson Disease

Wilson disease (WD) is characterized by hepatolenticular degeneration, but there is no report on apoptosis and anti-apoptotic markers in WD patients with neurological manifestation (WDN). The aim of this study was to evaluate active caspase-3 and X-linked inhibitors of apoptosis protein (XIAP) level in WDN and correlate these with disease severity and markers of death (tumor necrosis factor-alpha (TNF-α), interleukin (IL)-8, malondialdehyde (MDA), and Cu) and survival signals (glutathione). Fifty-four patients with WDN and 36 healthy matched controls were included. Their severity, Burke-Fahn-Marsden (BFM) scores, blood counts, hemoglobin, serum chemistry, ceruloplasmin, and free copper and 24-h urinary copper were measured. Cranial MRI findings were noted. Serum active caspase-3, XIAP, TNF-α, IL-8, and plasma glutathione and MDA were measured using enzyme-linked immunosorbent assay (ELISA), flow cytometry, and spectrophotometer respectively. In the patients with WDN, active caspase-3 (0.55 ± 0.11 vs 0.38 ± 0.06 ng/ml), TNF-α (76.05 ± 29.01 vs 36.05 ± 21.01 pg/ml), IL-8 (590.19 ± 89.19 vs 193.43 ± 71.01 pg/ml), and MDA (4.92 ± 0.39 vs 3.43 ± 0.21 nmol/ml) levels were increased whereas XIAP (84.66 ± 10.39 vs 95.76 ± 10.11 ng/ml) and glutathione (GSH) (2.03 ± 0.29 vs 2.98 ± 0.27 mg/dl) levels were decreased compared to controls. Active caspase-3 was correlated with neurological severity (r = 0.48), BFM score (r = 0.37), ceruloplasmin (r = -0.39), hemoglobin (r = -0.34), and serum Cu (r = 0.39). XIAP levels were correlated with neurological severity (r = -0.40), BFM (r = -0.51), serum Cu (r = -0.42), and ceruloplasmin (r = 0.34). The XIAP level positively correlated with survival (GSH) and inversely with death signals (TNF-α, IL-8, MDA and free serum Cu) whereas active caspase-3 positively correlated with death (TNF-α, IL-8, serum Cu, MDA) and inversely with survival signal (GSH). Serum active caspase-3 level increased in WDN and positively correlated with the severity of disease, death signals (TNF, IL-8, MDA, and free Cu) and inversely with GSH and XIAP.

Role of Oxidative Stress in the Worsening of Neurologic Wilson Disease Following Chelating Therapy

Patients with neurologic Wilson disease (NWD) may worsen on treatment, but there is no study evaluating the role of oxidative stress. We report the role of plasma glutathione (GSH), total antioxidant capacity (TAC) and malondialdehyde (MDA) in the worsening of NWD following treatment. Fifty-one treatment-naïve NWD patients were subjected to detailed clinical evaluation. The severity of NWD was noted, and dystonia was measured by Burke-Fahn-Marsden (BFM) score. Their hematological, serum chemistry, ultrasound abdomen and cranial MRI changes were noted. Plasma GSH, TAC and MDA, serum free copper (Cu) and 24-h urinary Cu were measured at admission and at 3 and 6 months after treatment. The patients were considered worsened if there was one or more grade deterioration in severity scale, >10 % deterioration in BFM score or appearance of new neurologic signs. The median age of the patients was 11 (5-37) years, and 12 were females. Following treatment, 25 patients improved, 12 worsened, and 14 had stationary course. The worsened group at 3 months had lower GSH (1.99 ± 0.17 vs. 2.30 ± 0.30 mg/dl; P = 0.004) and TAC (1.59 ± 0.12 vs. 1.82 ± 0.17 mmol Trolox equivalent/L; P = 0.001) and higher MDA (5.24 ± 0.22 vs. 4.34 ± 0.46 nmol/ml; P < 0.001) levels compared to the improved group. These changes were associated with increased serum free Cu (41.81 ± 3.31 vs. 35.62 ± 6.40 µg/dl; P = 0.02) and 24-h urinary Cu (206.42 ± 41.61 vs. 121.99 ± 23.72 µg/24 h; P < 0.001) in the worsened compared to the improved group. All the patients having worsening were on penicillamine. Worsening following chelating treatment in NWD may be due to oxidative stress which is induced by increased serum free Cu. These results may have future therapeutic implication and needs further study.

Triggers, inhibitors, mechanisms, and significance of eryptosis: the suicidal erythrocyte death

Suicidal erythrocyte death or eryptosis is characterized by erythrocyte shrinkage, cell membrane blebbing, and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include Ca(2+) entry, ceramide formation, stimulation of caspases, calpain activation, energy depletion, oxidative stress, and dysregulation of several kinases. Eryptosis is triggered by a wide variety of xenobiotics. It is inhibited by several xenobiotics and endogenous molecules including NO and erythropoietin. The susceptibility of erythrocytes to eryptosis increases with erythrocyte age. Phosphatidylserine exposing erythrocytes adhere to the vascular wall by binding to endothelial CXC-Motiv-Chemokin-16/Scavenger-receptor for phosphatidylserine and oxidized low density lipoprotein (CXCL16). Phosphatidylserine exposing erythrocytes are further engulfed by phagocytosing cells and are thus rapidly cleared from circulating blood. Eryptosis eliminates infected or defective erythrocytes thus counteracting parasitemia in malaria and preventing detrimental hemolysis of defective cells. Excessive eryptosis, however, may lead to anemia and may interfere with microcirculation. Enhanced eryptosis contributes to the pathophysiology of several clinical disorders including metabolic syndrome and diabetes, malignancy, cardiac and renal insufficiency, hemolytic uremic syndrome, sepsis, mycoplasma infection, malaria, iron deficiency, sickle cell anemia, thalassemia, glucose 6-phosphate dehydrogenase deficiency, and Wilson's disease. Facilitating or inhibiting eryptosis may be a therapeutic option in those disorders.

Mechanisms and pathophysiological significance of eryptosis, the suicidal erythrocyte death

Eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling, is stimulated by Ca(2+) entry through Ca(2+)-permeable, PGE2-activated cation channels, by ceramide, caspases, calpain, complement, hyperosmotic shock, energy depletion, oxidative stress, and deranged activity of several kinases (e.g. AMPK, GK, PAK2, CK1α, JAK3, PKC, p38-MAPK). Eryptosis is triggered by intoxication, malignancy, hepatic failure, diabetes, chronic renal insufficiency, hemolytic uremic syndrome, dehydration, phosphate depletion, fever, sepsis, mycoplasma infection, malaria, iron deficiency, sickle cell anemia, thalassemia, glucose 6-phosphate dehydrogenase deficiency, and Wilson's disease. Eryptosis may precede and protect against hemolysis but by the same token result in anemia and deranged microcirculation.

Oxidative stress and suicidal erythrocyte death

SIGNIFICANCE

Eryptosis, the suicidal erythrocyte death, is characterized by cell shrinkage, membrane blebbing, and phosphatidylserine translocation to the outer membrane leaflet. Phosphatidylserine at the erythrocyte surface binds endothelial CXCL16/SR-PSOX (CXC-Motiv-Chemokin-16/Scavenger-receptor-for-phosphatidylserine-and-oxidized-low-density-lipoprotein) and fosters engulfment of affected erythrocytes by phagocytosing cells. Eryptosis serves to eliminate infected or defective erythrocytes, but excessive eryptosis may lead to anemia and may interfere with microcirculation. Clinical conditions with excessive eryptosis include diabetes, chronic renal failure, hemolytic uremic syndrome, sepsis, malaria, iron deficiency, sickle cell anemia, thalassemia, glucose 6-phosphate dehydrogenase deficiency, glutamate cysteine ligase modulator deficiency, and Wilson's disease.

RECENT ADVANCES

Eryptosis is triggered by a wide variety of xenobiotics and other injuries such as oxidative stress. Signaling of eryptosis includes prostaglandin E₂ formation with subsequent activation of Ca(2+)-permeable cation channels, Ca(2+) entry, activation of Ca(2+)-sensitive K(+) channels, and cell membrane scrambling, as well as phospholipase A2 stimulation with release of platelet-activating factor, sphingomyelinase activation, and ceramide formation. Eryptosis may involve stimulation of caspases and calpain with subsequent degradation of the cytoskeleton. It is regulated by AMP-activated kinase, cGMP-dependent protein kinase, Janus-activated kinase 3, casein kinase 1α, p38 kinase, and p21-activated kinase 2. It is inhibited by erythropoietin, antioxidants, and further small molecules.

CRITICAL ISSUES

It remains uncertain for most disorders whether eryptosis is rather beneficial because it precedes and thus prevents hemolysis or whether it is harmful because of induction of anemia and impairment of microcirculation.

FUTURE DIRECTIONS

This will address the significance of eryptosis, further mechanisms underlying eryptosis, and additional pharmacological tools fostering or inhibiting eryptosis.

Treatment with D-penicillamine or zinc sulphate affects copper metabolism and improves but not normalizes antioxidant capacity parameters in Wilson disease

Copper accumulation in tissues due to a biallelic pathogenic mutation of the gene: ATP7B results in a clinical phenotype known as Wilson disease (WD). Aberrations in copper homeostasis can create favourable conditions for superoxide-yielding redox cycling and oxidative tissue damage. Drugs used in WD treatment aim to remove accumulated copper and normalise the free copper concentration in the blood. In the current study the effect of decoppering treatment on copper metabolism and systemic antioxidant capacity parameters was analyzed. Treatment naïve WD patients (TNWD) (n = 33), those treated with anti-copper drugs (TWD) (n = 99), and healthy controls (n = 99) were studied. Both TNWD and TWD patients characterised with decreased copper metabolism parameters, as well as decreased total antioxidant potential (AOP), glutathione (GSH) level, activity of catalase, glutathione peroxidase (GPx), and S-transferase glutathione, compared to controls. TWD patients had significantly lower copper metabolism parameters, higher total AOP and higher levels of GSH than TWD individuals; however, no difference was observed between these two patient groups with respect to the rest of the antioxidant capacity parameters. Patients who had undergone treatment with D-penicillamine or zinc sulphate did not differ with respect to copper metabolism or antioxidant capacity parameters, with the exception of GPx that was lower in D-penicillamine treated individuals. These data suggest that anti-copper treatment affects copper metabolism as well as improves, but does not normalize, natural antioxidant capacity in patients with WD. We propose to undertake studies aimed to evaluate the usefulness of antioxidants as well as selenium as a supplemental therapy in WD.

A review and current perspective on Wilson disease

Wilson disease is a rare, inherited autosomal recessive disease of copper metabolism and may be more common where consanguinity is prevalent. Much has been known about the disease after it was first described by Kinnier Wilson as 'progressive lenticular degeneration in 1912. Over 500 mutations of the ATP7B gene has been identified with no clear genotype to phenotype correlation. Loss of ATP7B function leads various grades of reduced biliary excretion of copper and reduced incorporation of copper into ceruloplasmin; accumulation and toxicity of copper in the liver, brain and other tissues results in liver toxicity and other myriad manifestations of the disease. The clinical features may vary from asymptomatic state to chronic liver disease, acute liver failure, neuropsychiatric manifestations and hemolytic anemia. Diagnosis is based on the combination of clinical sign's, biochemical features, histologic findings and mutation analysis of ATP7B gene. Subtle geographical differences exist with a disproportionate proportion of children presenting with acute liver failure. A high index of suspicion is needed for an early diagnosis. Ratios of biochemical indices for early diagnosis need validation across geographical regions and may not be particularly applicable in children. Better biomarkers or the need for tests for early detection of ALF persists. Drugs used in the treatment of Wilson disease include copper chelating agents such as d-Penicillamine, trientine and zinc salt. Untreated Wilson disease uniformly leads to death from liver disease or severe neurological disability. Early recognition and treatment has excellent prognosis. Liver transplantation is indicated in acute liver failure and end stage liver disease. Family screening in order to detect the disorder in the first-degree relatives is warranted. This review provides an overview of different aspects of Wilson disease including geographical differences in presentations and clinical management and the limitations of currently available tests.

Fatty liver and anti-oxidant enzyme activities along with peroxisome proliferator-activated receptors γ and α expressions in the liver of Wilson's disease

BACKGROUND

The mechanisms of liver damage and steatosis in Wilson's disease (WD) presenting accumulation of copper generating oxidants remain unclear. Recent studies have shown that peroxisome proliferator-activated receptors (PPARs), in particular PPARs α and γ, regulate fat content of the liver together with the anti-oxidant and anti-inflammation systems. However, such PPARs have never been studied in WD.

METHODS

We examined PPARs along with the liver damage and steatosis of WD using liver specimens from affected patients exhibiting mild liver damage (group I, n = 5), moderate or greater liver damage (group II, n = 10) and fulminant hepatic failure (group III, n = 5), and from asymptomatic carriers (group H, n = 4).

RESULTS

PPAR α expression was increased over the control levels in groups H and I but was decreased in groups II and III in parallel with the progression of liver damage (group H = I>II>III). PPAR γ expression was inversely increased (group H<I<II<III). Mn-dependent superoxide dismutase (Mn-SOD), CuZn-SOD, and catalase activities were decreased in the affected three groups, and were increased in group H. Among group II exhibiting substantial inter-individual variances in parameters, the severity of steatosis showed a significant positive correlation with PPAR γ expression (p<0.001) but not PPAR α expression. CuZn-SOD activity was positively correlated with PPARα expression (p<0.05) but not PPAR γ expression.

CONCLUSION

These results suggest that changes of PPARs γ and α are associated with the steatosis and the impairment of anti-oxidant system in the liver of WD.

Cerebral antioxidant enzyme increase associated with learning deficit in type 2 diabetes rats

In this study, we examined alterations in the enzymatic antioxidant defenses associated with learning deficits induced by type 2 diabetes, and studied the effects of the peroxisome proliferator-activated receptor γ agonist pioglitazone on these learning deficits. Learning ability was assessed by visual discrimination tasks in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, as a model of spontaneous type 2 diabetes. Levels of the antioxidant enzymes glutathione peroxidase (GPx), Cu(2+)-Zn(2+) superoxide dismutase (CuZn-SOD) and manganese SOD were measured in the cortex, hippocampus and striatum. Half the rats received oral pioglitazone (20mg/kg/day) from the early stage of diabetes (22 weeks old) to 27 weeks old. OLETF rats showed learning deficits compared with control, Long-Evans Tokushima Otsuka (LETO) rats. GPx levels in the cortex and hippocampus were increased in OLETF rats compared with LETO rats, with an inverse correlation between GPx in the hippocampus and learning score. CuZn-SOD levels were also increased in the hippocampus in OLETF rats. Pioglitazone reduced blood glucose and increased serum adiponectin levels, but had no effect on learning tasks or antioxidant enzymes, except for CuZn-SOD. These results suggest that an oxidative imbalance reflected by increased brain antioxidant enzymes plays an important role in the development of learning deficits in type 2 diabetes. Early pioglitazone administration partly ameliorated diabetic symptoms, but was unable to completely recover cerebral oxidative imbalance and functions. These results suggest that diabetes-induced brain impairment, which results in learning deficits, may have occurred before the appearance of the symptoms of overt diabetes.

Decreased serum antioxidant capacity in patients with Wilson disease is associated with neurological symptoms

BACKGROUND & AIMS

Wilson disease (WD) is an inherited disorder of copper disposition caused by an ATP7B transporter gene mutation, leading to copper accumulation in predisposed tissues. In addition to a genetic predisposition, other factors are likely to contribute to its clinical manifestation. The aim of the study was to assess whether oxidative stress affects the phenotypic manifestation of WD.

METHODS

In 56 patients with WD (29 men; 26 with the hepatic form, 22 with the neurologic form, and eight asymptomatic; mean age 38.5 ± 12 years), total serum antioxidant capacity (TAC) and inflammatory parameters (hs-CRP, IL-1β, IL-2, IL-6, IL-10, and TNF-α) were analyzed and related to the clinical manifestation, and mutations of the ATP7B gene. The control group for the TAC and inflammatory parameters consisted of 50 age- and gender-matched healthy individuals.

RESULTS

WD patients had a significantly lower TAC (p < 0.00001), lower IL-10 levels (p = 0.039), as well as both higher IL-1β (p = 0.019) and IL-6 (p = 0.005) levels compared to the control subjects. TNF-α, hs-CRP, and IL-2 did not differ from the controls. Patients with the neurological form of WD had a significantly lower TAC than those with the hepatic form (p < 0.001). In addition, the lower TAC was associated with the severity of the neurological symptoms (p = 0.02). No relationship between the inflammatory parameters and clinical symptoms was found.

CONCLUSIONS

Data from our study suggest that the increased oxidative stress contributes significantly to the clinical manifestation of WD; as a lower TAC is associated with the neurological symptoms in WD patients.

Administration of PPARβ/δ agonist reduces copper-induced liver damage in mice: possible implications in clinical practice

In this study we investigated if peroxisome proliferator-activated receptor β/δ activation protects from copper-induced acute liver damage. Mice treated with copper had significant body weight loss, serum alanine aminotransferase increase, modest changes in liver histology, increase of tumor necrosis factor α and macrophage inflammatory protein 2 mRNA and 8-hydroxy-2'-deoxyguanosine. Mice treated with copper and peroxisome proliferator-activated receptor β/δ agonist GW0742 had significantly less body weight loss, less serum alanine aminotransferase increase, less tumor necrosis factor α, macrophage inflammatory protein-2 and 8-hydroxy-2'-deoxyguanosine upregulation than copper treated mice. The opposite effect was observed in mice treated with copper and peroxisome proliferator-activated receptor β/δ antagonist GSK0660. In vitro, copper induced reactive oxygen species, which was lower in cells treated with GW0742 or transfected with peroxisome proliferator-activated receptor β/δ expression vector; together, transfection and GW0742 had an additive reactive oxygen species-reducing effect. Copper also upregulated Fas ligand and Caspase 3/7 activity, effects that were significantly lower in cells also treated with GW0742. In conclusion, peroxisome proliferator-activated receptor β/δ activation reduced copper-induced reactive oxygen species, pro-inflammatory and acute phase reaction cytokines in mice liver. Peroxisome proliferator-activated receptor β/δ agonists could become useful in the management of copper-induced liver damage.

Late diagnosed Wilson disease with hepatic and neurological manifestations

A 50-year-old woman was referred to our hospital due to liver dysfunction and progressive neurological symptoms. She had previously been diagnosed with nonalcoholic steatohepatitis (NASH). Ursodeoxycholic acid (UDCA) had effectively normalized her serum aminotransferase levels, however, she presented with loss of balance, dysarthria and difficulty in handwriting. Autoantibodies and hepatitis virus markers were negative. Serum ceruloplasmin and copper levels were noted to be 9 mg/dL and 32 µg/dL, respectively. The 24-h urinary copper excretion was 331.8 µg/day. Kayser-Fleischer ring was demonstrated. Histological examination of the liver revealed inflammatory infiltrate and fibrosis, and the hepatic copper concentration was 444.4 µg/g dry weight. We diagnosed her as having Wilson disease and started treatment with trientine. Immuohistochemistry for keratin 8 and p62 demonstrated Mallory-Denk bodies. Many of the p62-expressing cells were positive for 4-Hydroxy-2-nonenal (HNE). Few Ki-67-positive hepatocytes were present in the liver. Wilson disease is one of the causes of NASH and UDCA may be a supportive therapeutic agent for Wilson disease. Cell proliferation is suppressed under copper-loaded conditions and this phenomenon may be associated with the clinical course of Wilson disease.

Elevated copper remodels hepatic RNA processing machinery in the mouse model of Wilson's disease

Copper is essential to mammalian physiology, and its homeostasis is tightly regulated. In humans, genetic defects in copper excretion result in copper overload and Wilson's disease (WD). Previous studies on the mouse model for WD (Atp7b(-)(/-)) revealed copper accumulation in hepatic nuclei and specific changes in mRNA profile prior to the onset of pathology. To find a molecular link between nuclear copper elevation and changes in hepatic transcriptome, we utilized quantitative ionomic and proteomic approaches. X-ray fluorescence and inductively coupled plasma mass spectrometry analysis indicate that copper in the Atp7b(-/-) nucleus, while highly elevated, does not markedly alter nuclear ion content. Widespread protein oxidation is also not observed, although the glutathione reductase SelH is upregulated, likely to maintain redox balance. We further demonstrate that accumulating copper affects the abundance and/or modification of a distinct subset of nuclear proteins. These proteins populate pathways that are most significantly associated with RNA processing. An alteration in splicing pattern was observed for hnRNP A2/B1, itself the RNA shuttling factor and spliceosome component. Analysis of hnRNP A2/B1 mRNA and protein revealed an increased retention of exon 2 and a selective 2-fold upregulation of a corresponding protein splice variant. Mass spectrometry measurements suggest that the nucleocytoplasmic distribution of RNA binding proteins, including hnRNP A2/B1, is altered in the Atp7b(-/-) liver. We conclude that remodeling of the RNA processing machinery is an important component of cell response to elevated copper that may guide pathology development in the early stages of WD.

Developmental changes in hepatic antioxidant capacity are age-and sex-dependent

Developmental inadequacy in hepatic antioxidant defenses may contribute to chemical toxicity and pediatric liver diseases. We measured a comprehensive panel of antioxidants in liver tissue from 27 normal pediatric donors. Glutathione reductase declined with age (P = 0.008, r = -0.54, Spearman) while microsomal glutathione-S-transferase increased (GST, P<0.001, r = 0.81). Males had significantly lower superoxide dismutase and vitamin E (P<0.05) and may have lower glutathione reductase (P = 0.06), while females show less cytosolic GST (P = 0.07). Hepatic antioxidants are high in neonates, decline throughout childhood, and then increase in adolescence to adult levels.