Wilson's disease and other neurological copper disorders

How to use tests for disorders of copper metabolism

In paediatrics, one of our main aims in the diagnostic process is to identify any treatable conditions. The copper metabolism disorder Wilson's disease (WD) is one such condition that is caused by mutations in the ATP7B gene. Delay in treatment could result in irreversible disability or even death. Although liver disease is the most common presenting feature in children, some children may initially present with a subtle neurological presentation only. In patients presenting with dystonia, tremor, dysarthria or with a deterioration in school performance, there should be a high index of suspicion for WD. However, the differential of these clinical presentations is wide and exclusion of WD is difficult. No single diagnostic test can exclude WD and each of the biochemical tests has limitations. In this article, we discuss copper metabolism disorders including WD and Menke's disease. We then discuss the available diagnostic tests and how to investigate children for these rare disorders.

An inductively coupled plasma mass spectrometry method for relative free copper determination and generation of a paediatric reference interval

Background

Diagnosis of Wilson’s disease is currently performed using caeruloplasmin as a first-line screening test; however, this test has well-described limitations. Monitoring of known Wilson’s disease patients often uses 24-h urine collection; however, this is inaccurate in children. Methods for directly measuring plasma free copper have been described, but no reference interval data exist for a paediatric population.

Methods

An inductively coupled plasma mass spectrometry method for measuring free copper was developed and validated, using ultracentrifugation. A paediatric reference interval was generated using 85 plasma samples from children attending outpatient clinics at University Hospital Southampton.

Results

Results showed no significant contamination of copper using the ultracentrifugation technique, and validation showed the method was accurate and precise with an analytical coefficient of variation between 5 and 7% depending on the concentration of free copper.

Conclusions

We describe the use and validation of an ultrafiltration inductively coupled plasma mass spectrometry method for plasma free copper with the first published paediatric reference interval. Free copper could provide much needed assistance for the monitoring of Wilson’s disease in children and also for adults.

Genotype and clinical course in 2 Chinese Han siblings with Wilson disease presenting with isolated disabling premature osteoarthritis: A case report

RATIONALE

Premature osteoarthritis (POA) is a rare condition in Wilson disease (WD). Particularly, when POA is the only complaint of a WD patient for a long time, there would be misdiagnosis or missed diagnosis and then treatment delay.

PATIENT CONCERNS AND DIAGNOSIS

Two Chinese Han siblings were diagnosed as WD by corneal K-F rings, laboratory test, and mutation analysis. They presented with isolated POA during the first 2 decades or more of their disease course, and were of missed diagnosis during that long time. The older affected sib became disabled due to his severe osteoarthritis when he was as young as 38 years old. Two compound heterozygous pathogenic variants c.2790_2792del and c.2621C>T were revealed in the ATP7B gene through targeted next-generation sequencing (NGS).

LESSONS

Adolescent-onset POA could be the only complaint of WD individual for at least 2 decades. Long delay in the treatment of WD's POA could lead to disability in early adulthood. Detailed physical examination, special biochemical test, and genotyping through targeted NGS should greatly reduce diagnosis delay in atypical WD patients with isolated POA phenotype.

Epidemiology, diagnosis, and treatment of Wilson's disease

Wilson's disease (WD) is an autosomal recessive disease caused by a mutation of the ATP7B gene, resulting in abnormal copper metabolism. The major clinical features of WD include liver disease, neurological disorders, K-F rings, and osteoporosis. The prevalence of WD in China is higher than that in Western countries. Early diagnosis and lifelong treatment will lead to better outcomes. Drugs such as sodium dimercaptosuccinate (Na-DMPS), Zn, and Gandou Decoction can be used to treat WD. Some studies have shown that the combination of traditional Chinese medicine and Western medicine is the best approach to treating WD. In order to identify better treatments, this article describes the specific clinical symptoms of Wilson's disease, its diagnosis, and treatment options.

The Efficacy and Pharmacological Mechanism of Zn7MT3 to Protect against Alzheimer's Disease

Alzheimer’s disease (AD) is one of the leading causes of death for people over 65 years. Worse still, no completely effective therapeutic agent is available so far. One important pathological hallmark of AD is accumulated amyloid-β (Aβ) plaques with dysregulated metal homeostasis. Human metallothionin 3 (MT3), a regulator of metal homeostasis, is downregulated at least 30% in AD brain. So far, some in vitro studies demonstrated its multiple functions related to AD. However, it is a great pity that systematic in vivo studies of MT3 on AD model animals are still a blank so far. In this study, we treated APP/PS1 mice with sustained drug release of Zn₇MT3 directly to the central nervous system, and investigated the role and molecular mechanism of Zn₇MT3 to protect against AD mice systematically. The results demonstrated that Zn₇MT3 can significantly ameliorate cognitive deficits, regulate metal homeostasis, abolish Aβ plaque load, and reduce oxidative stress. Additionally, it has been confirmed that MT3 is penetrable to the blood brain barrier of AD mice. All these results support that Zn₇MT3 is an effective AD suppressing agent and has potential for applications in Alzheimer’s disease therapy.

Bis-choline tetrathiomolybdate in patients with Wilson's disease: an open-label, multicentre, phase 2 study

BACKGROUND

Wilson's disease is a genetic disorder in which copper accumulates in the liver, brain, and other tissues. Therapies are limited by efficacy, safety concerns, and multiple daily dosing. Bis-choline tetrathiomolybdate (WTX101) is an oral first-in-class copper-protein-binding molecule that targets hepatic intracellular copper and reduces plasma non-ceruloplasmin-bound copper (NCC) by forming tripartite complexes with albumin and increasing biliary copper excretion. We aimed to assess the efficacy and safety of WTX101 in the initial or early treatment of patients with Wilson's disease.

METHODS

We did this open-label, phase 2 study at 11 hospitals in the USA and Europe. We enrolled patients (≥18 years) with Wilson's disease who were untreated or had received no more than 24 months of treatment with chelators or zinc, had a Leipzig score of 4 or more, and had NCC concentrations above the lower limit of the normal reference range (≥0·8 μmol/L). Eligible patients received WTX101 monotherapy at a starting dose of 15-60 mg/day on the basis of baseline NCC concentrations for the first 4-8 weeks, with response-guided individualised dosing for the remaining weeks up to week 24. Investigators, other hospital personnel, and patients were aware of the identity of the treatment. The primary endpoint was change in baseline NCC concentrations corrected for copper in tetrathiomolybdate-copper-albumin complexes (NCC_corrected) at 24 weeks, with treatment success defined as achievement or maintenance of normalised NCC_corrected (≤2·3 μmol/L [upper limit of normal]) or achievement of at least a 25% reduction in NCC_corrected from baseline at 24 weeks. This study is registered with ClinicalTrials.gov, number NCT02273596.

FINDINGS

Between Nov 24, 2014, and April 27, 2016, 28 patients were enrolled and received WTX101; 22 (79%) patients completed the study up to week 24. At 24 weeks, 20 (71%, 95% CI 51·3-86·8; p<0·0001) of 28 patients met the criteria for treatment success: 16 (57%) treated with WTX101 either achieved or maintained normalised NCC_corrected concentrations and 4 (14%) had at least a 25% reduction from baseline NCC_corrected. Mean NCC_corrected was reduced by 72% from baseline to week 24 (least squares mean difference -2·4 μmol/L [SE 0·4], 95% CI -3·2 to -1·6; p<0·0001). No cases of paradoxical drug-related neurological worsening were recorded. Liver function was stable in all patients, although reversible increased concentrations of asymptomatic alanine or aspartate aminotransferase, or γ-glutamyltransferase, without increased bilirubin, occurred in 11 (39%) of 28 patients who received at least 30 mg/day. 11 serious adverse events were reported in seven (25%) patients and included psychiatric disorders (six events in four patients), gait disturbance (one event), elevated liver aminotransferases (two events in two patients, one with agranulocytosis), and decline in neurological functioning (one event, likely due to natural disease progression although causality could not be ruled out). The seven serious adverse events categorised as psychiatric disorders and as gait disturbance were assessed as unlikely to be related to the study drug, whereas the remaining four events were possibly or probably related.

INTERPRETATION

Our findings indicate that WTX101 might be a promising new therapeutic approach for Wilson's disease, with a unique mode of action. In view of its once-daily dose and favourable safety profile, WTX101 could improve the treatment of patients with this debilitating condition.

FUNDING

Wilson Therapeutics AB.

Colorimetric assay of copper ions based on the inhibition of peroxidase-like activity of MoS2 nanosheets

The peroxidase-like catalytic activity of MoS₂ nanomaterials has been utilized for colorimetric bioassays and medical diagnostics. However, the application of peroxidase-like catalytic activity of MoS₂ nanomaterials in environmental analysis was seldom explored. Herein, copper ions were found to inhibit the peroxidase-like catalytic activity of MoS₂ nanosheets, which can catalyze the oxidation of 3, 3', 5, 5'-tetramethylbenzidine by H₂O₂ to produce a colorimetric product. Based on this finding, a simple sensitive colorimetric method for the detection of copper ions was developed. In the presence of copper ions, the absorbance and color of the solution decreased with the increasing concentration of copper ions. The color of the solution can be used to semi-quantitative on-site assay of copper ions by naked eyes. A linear relationship between the absorbance and the concentration of copper ions was observed in the range of 0.4-4.0μmolL^-1 with a detection limit of 92nmolL^-1, which was much lower than the maximum contaminant level of copper in drinking water legislated by the Environmental Protection Agency of USA and the World Health Organization. The method was applied to detect copper ions in environmental water samples with satisfactory results.

Facile Synthesis of Fluorescent Conjugated Polyelectrolytes Using Polydentate Sulfonate as Highly Selective and Sensitive Copper(II) Sensors

Fluorescent conjugated polyelectrolytes represent an exciting area of research into new chemosensors. By virtue of their rapid electron and energy transfer paths, these highly correlated, one-dimensional systems have been depicted as "molecular wires" and show "million-fold" sensitivity compared to monomolecular sensor analogs. In this paper, a novel polyelectrolyte sensor, the ttp-PPESO₃, has been designed by incorporating terpyridine and sulfonate functional groups into the polyelectrolyte. This specifically tailored sensor has displayed remarkable quenching response toward copper(II) with a detection limit of 14.7 nM (0.93 ppb). It is capable of selectively screening copper without interference from 12 common cations. Molecular modeling suggests that binding occurs through a coordination interaction of the terpyridine and sulfonate. The additional multidentate nature from the sulfonate offers extraordinary chelating ability to the analyte. We anticipate that this unique binding mode will provide insight for the design of future more sensitive and selective systems.

Evaluation of Kayser-Fleischer ring in Wilson disease by anterior segment optical coherence tomography

Purpose:

The purpose of the study is to present anterior segment optical coherence tomography (AS-OCT) as an alternative method of evaluating Kayser–Fleischer (KF) ring in Wilson disease (WD) not only by ophthalmologists but also by other clinicians dealing with WD.

Materials and Methods:

This was a retrospective case series of six WD patients with KF ring. Evaluation of KF ring was done by naked eye examination using torch light, slit lamp biomicroscopy (SL), and AS-OCT. SL examination was done using a narrow slit of the superior cornea. AS-OCT was done using the Optovue RTvue Premier™ device (Fremont, CA, USA).

Results:

AS-OCT revealed KF ring as an intense hyperreflective band at the level of Descemet membrane (DM). Color scale of AS-OCT showed KF ring as greenish/greenish yellow/orange yellow/yellowish/red band. Validation of AS-OCT findings was done by second ophthalmologist, medical gastroenterologist, surgical gastroenterologist, and neurophysician. After seeing the first observation, they could identify the AS-OCT features in all pictures with ease.

Conclusions:

This is the first observation of KF ring in WD on AS-OCT. On AS-OCT, KF ring is visualized as intense hyperreflectivity at the level of DM in the peripheral cornea. Further, studies are needed to evaluate the usefulness of AS-OCT in WD management.

Treatable inherited rare movement disorders

There are many rare movement disorders, and new ones are described every year. Because they are not well recognized, they often go undiagnosed for long periods of time. However, early diagnosis is becoming increasingly important. Rapid advances in our understanding of the biological mechanisms responsible for many rare disorders have enabled the development of specific treatments for some of them. Well-known historical examples include Wilson disease and dopa-responsive dystonia, for which specific and highly effective treatments have life-altering effects. In recent years, similarly specific and effective treatments have been developed for more than 30 rare inherited movement disorders. These treatments include specific medications, dietary changes, avoidance or management of certain triggers, enzyme replacement therapy, and others. This list of treatable rare movement disorders is likely to grow during the next few years because a number of additional promising treatments are actively being developed or evaluated in clinical trials. © 2017 International Parkinson and Movement Disorder Society.

Wilson disease: At the crossroads between genetics and epigenetics-A review of the evidence

Environmental factors, including diet, exercise, stress, and toxins, profoundly impact disease phenotypes. This review examines how Wilson disease (WD), an autosomal recessive genetic disorder, is influenced by genetic and environmental inputs. WD is caused by mutations in the copper-transporter gene ATP7B, leading to the accumulation of copper in the liver and brain, resulting in hepatic, neurological, and psychiatric symptoms. These symptoms range in severity and can first appear anytime between early childhood and old age. Over 300 disease-causing mutations in ATP7B have been identified, but attempts to link genotype to the phenotypic presentation have yielded little insight, prompting investigators to identify alternative mechanisms, such as epigenetics, to explain the highly varied clinical presentation. Further, WD is accompanied by structural and functional abnormalities in mitochondria, potentially altering the production of metabolites that are required for epigenetic regulation of gene expression. Notably, environmental exposure affects the regulation of gene expression and mitochondrial function. We present the "multi-hit" hypothesis of WD progression, which posits that the initial hit is an environmental factor that affects fetal gene expression and epigenetic mechanisms and subsequent "hits" are environmental exposures that occur in the offspring after birth. These environmental hits and subsequent changes in epigenetic regulation may impact copper accumulation and ultimately WD phenotype. Lifestyle changes, including diet, increased physical activity, stress reduction, and toxin avoidance, might influence the presentation and course of WD, and therefore may serve as potential adjunctive or replacement therapies.

Mitochondrial Ferredoxin Determines Vulnerability of Cells to Copper Excess

The essential micronutrient copper is tightly regulated in organisms, as environmental exposure or homeostasis defects can cause toxicity and neurodegenerative disease. The principal target(s) of copper toxicity have not been pinpointed, but one key effect is impaired supply of iron-sulfur (FeS) clusters to the essential protein Rli1 (ABCE1). Here, to find upstream FeS biosynthesis/delivery protein(s) responsible for this, we compared copper sensitivity of yeast-overexpressing candidate targets. Overexpression of the mitochondrial ferredoxin Yah1 produced copper hyper-resistance. ⁵⁵Fe turnover assays revealed that FeS integrity of Yah1 was particularly vulnerable to copper among the test proteins. Furthermore, destabilization of the FeS domain of Yah1 produced copper hypersensitivity, and YAH1 overexpression rescued Rli1 dysfunction. This copper-resistance function was conserved in the human ferredoxin, Fdx2. The data indicate that the essential mitochondrial ferredoxin is an important copper target, determining a tipping point where plentiful copper supply becomes excessive. This knowledge could help in tackling copper-related diseases.

The crystal structures of a copper-bound metallochaperone from Saccharomyces cerevisiae

Atx1 is a metallochaperone protein from the yeast Saccharomyces cerevisiae (yAtx1) that plays a major role in copper homeostasis in this organism. yAtx1 functions as a copper transfer protein by shuttling copper to the secretory pathway to control intracellular copper levels. Here we describe the first crystal structures of yAtx1 that have been determined in the presence of Cu(I). The structures from two different crystal forms have been solved and refined to resolutions of 1.65 and 1.93Å. In contrast to the previous metallated crystal structure of yAtx1 where a single Hg(II) atom was coordinated by one yAtx1 molecule, the Cu(I)-yAtx1 was crystallised as a dimer in both crystal forms, sharing one Cu(I) atom between two yAtx1 molecules. This is consistent with the crystal structure of the human homologue Cu(I)-hAtox1. Overall the structures in the two different crystal forms of Cu(I)-yAtx1 are remarkably similar to that of Cu(I)-hAtox1. However, subtle structural differences between Cu(I)-yCtr1 and Cu(I)-hAtox1 are observed in copper coordination geometries and in the conformations of Loop 2, with the latter potentially contributing to differential interactions and copper transfer mechanisms with membrane transport copper uptake systems.

Measurements of serum non-ceruloplasmin copper by a direct fluorescent method specific to Cu(II)

BACKGROUND

Meta-analyses indicated the breakdown of copper homeostasis in the sporadic form of Alzheimer's disease (AD), comprising copper decreases within the brain and copper increases in the blood and the pool not bound to ceruloplasmin (non-Cp Cu, also known in the literature as "free" copper). The calculated non-Cp Cu (Walshe's) index has many limitations.

METHODS

A direct fluorescent method for non-Cp Cu detection has been developed and data are presented herein. The study included samples from 147 healthy subjects, 36 stable mild cognitive impairment (MCI) and 89 AD patients, who were tested for non-Cp Cu through the direct method, total serum copper, ceruloplasmin concentration and o-dianisidine ceruloplasmin activity. The indirect non-Cp Cu Walshe's index was also calculated.

RESULTS

The direct method was linear (0.9-5.9 μM), precise (within-laboratory coefficient variation of 9.7% for low and 7.1% for high measurements), and had a good recovery. A reference interval (0-1.9 μM) was determined parametrically in 147 healthy controls (27-84 years old). The variation of non-Cp Cu was evaluated according to age and sex. Non-Cp Cu was 1.5 times higher in AD patients (regarding the upper value of the reference interval) than in healthy controls. Healthy, MCI and AD subjects were differentiated through the direct non-Cp Cu method [areas under the curve (AUC)=0.755]. Considering a 95% specificity and a 1.91 μmol/L cut-off, the sensitivity was 48.3% (confidence interval 95%: 38%-58%). The likelihood ratio (LR) was 9.94 for positive test results (LR+) and 0.54 for negative test result (LR-).

CONCLUSIONS

The direct fluorescent test reliably and accurately measures non-Cp Cu, thereby determining the probability of having AD.

Inhibitory rTMS applied on somatosensory cortex in Wilson's disease patients with hand dystonia

Hand dystonia is a common complication of Wilson's disease (WD), responsible for handwriting difficulties and disability. Alteration of sensorimotor integration and overactivity of the somatosensory cortex have been demonstrated in dystonia. This study investigated the immediate after effect of an inhibitory repetitive transcranial magnetic stimulation (rTMS) applied over the somatosensory cortex on the writing function in WD patients with hand dystonia. We performed a pilot prospective randomized double-blind sham-controlled crossover rTMS study. A 20-min 1-Hz rTMS session, stereotaxically guided, was applied over the left somatosensory cortex in 13 WD patients with right dystonic writer's cramp. After 3 days, each patient was crossed-over to the alternative treatment. Patients were clinically evaluated before and immediately after each rTMS session with the Unified Wilson's Disease rating scale (UWDRS), the Writers' Cramp Rating Scale (WCRS), a specifically designed scale for handwriting difficulties in Wilson's disease patients (FAR, flow, accuracy, and rhythmicity evaluation), and a visual analog scale (VAS) for handwriting discomfort. No significant change in UWDRS, WCRS, VAS, or FAR scores was observed in patients treated with somatosensory inhibitory rTMS compared to the sham protocol. The FAR negatively correlated with UWDRS (r = -0.6; P = 0.02), but not with the WCRS score, disease duration, MRI diffusion lesions, or with atrophy scores. In our experimental conditions, a single inhibitory rTMS session applied over somatosensory cortex did not improve dystonic writer cramp in WD patients.

Subacute copper-deficiency myelopathy in a patient with occult celiac disease

CONTEXT

Acquired copper deficiency represents a rare cause of progressive myelopathy presenting with sensory ataxia and spastic gait. The time interval from neurological symptoms onset to diagnosis of myelopathy ranges from 2 months to several years in almost all cases, mimicking the clinical course of subacute combined degeneration due to vitamin B12 deficiency.

FINDINGS

A 60-year-old man, without any gastrointestinal symptoms, developed over the course of one week rapidly progressive gait imbalance, tingling and numbness in his feet and ascending lower limb weakness. Spine magnetic resonance imaging revealed hyperintensity involving cervical and dorsal posterior columns of spinal cord. Blood analysis revealed undetectable serum copper levels, low serum ceruloplasmin and positive serum Immunoglobulin A anti-tissue transglutaminase. Upper gastrointestinal endoscopy was performed revealing duodenal villous atrophy consistent with a malabsorption pattern. A gluten-free diet in association with intravenous then oral copper supplementation prompted sustained normalization of serum copper levels and progressive clinical improvement.

CONCLUSION/CLINICAL RELEVANCE

We report a rare case of myelopathy induced by copper deficiency secondary to undiagnosed celiac disease, peculiarly presenting with a subacute onset. This case expands the neurological presentation and clinical course of myelopathy due to acquired copper deficiency. We suggest investigation of copper deficiency in patients presenting with subacute or even acute sensory ataxia and spastic gait. Detection of hypocupremia in patients without a previous history of gastric surgery should lead to diagnostic testing for celiac disease even in the absence of any obvious gastrointestinal symptoms.

The double-edged role of copper in the fate of amyloid beta in the presence of anti-oxidants

The biological fate of amyloid beta (Aβ) species is a fundamental question in Alzheimer's disease (AD) pathogenesis. The competition between clearance and aggregation of Aβs is critical for the onset of AD. Copper has been widely considered to be an inducer of harmful crosslinking of Aβs, and an important triggering factor for the onset of AD. In this report, however, we present data to show that copper can also be an inducer of Aβ degradation in the presence of a large excess of well-known intrinsic (such as dopamine) or extrinsic (such as vitamin C) anti-oxidants. The degraded fragments were identified using SDS-Page gels, and validated via nanoLC-MS/MS. A tentative mechanism for the degradation was proposed and validated with model peptides. In addition, we performed electrophysiological analysis to investigate the synaptic functions in brain slices, and found that in the presence of a significant excess of vitamin C, Cu(ii) could prevent an Aβ-induced deficit in synaptic transmission in the hippocampus. Collectively, our evidence strongly indicated that a proper combination of copper and anti-oxidants might have a positive effect on the prevention of AD. This double-edged function of copper in AD has been largely overlooked in the past. We believe that our report is very important for fully understanding the function of copper in AD pathology.

Hepatocellular Carcinoma: An Unusual Complication of Longstanding Wilson Disease

Wilson disease is caused by the accumulation of copper in the liver, brain or other organs, due to the mutation in ATP7B gene, which encodes protein that helps in excretion of copper in the bile canaliculus. Clinical presentation varies from asymptomatic elevation of transaminases to cirrhosis with decompensation. Hepatocellular carcinoma is a known complication of cirrhosis, but a rare occurrence in Wilson disease. We present a case of neurological Wilson disease, who later developed decompensated cirrhosis and hepatocellular carcinoma.

Memory and Learning Dysfunction Following Copper Toxicity: Biochemical and Immunohistochemical Basis

The prototype disease of Cu toxicity in human is Wilson disease, and cognitive impairment is the presenting symptom of it. There is no study correlating Cu-induced excitotoxicity, apoptosis, and astrocytic reaction with memory dysfunction. We report excitotoxicity, apoptosis, and astrocytic reaction of the hippocampus and frontal cortex with memory dysfunction in rat model of Cu toxicity. Thirty-six rats were divided into group I (control) and group II (100 mg/kgBwt/day CuSO₄ orally). Y-maze was performed for memory and learning at 0, 30, 60, and 90 days. Frontal and hippocampal free Cu concentration, oxidative stress markers [glutathione (GSH), total antioxidant toxicity (TAC), and malondialdehyde (MDA)], and glutamate were measured by atomic absorption spectroscopy, spectrophotometry, and ELISA, respectively. N-methyl-D-aspartate receptors (NMDARs) NR1, NR2A, and NR2B were done by real-time polymerase chain reaction. Immunohistochemistry for caspase-3 and glial fibrillary acidic protein (GFAP) were done and quantified using the ImageJ software. The glutamate level in hippocampus was increased, and NMDAR expression was decreased at 30, 60, and 90 days in group II compared to group I. In the frontal cortex, glutamate was increased at 90 days, but NMDARs were not significantly different in group II compared to group I. Caspase-3 and GFAP expressions were also higher in group II compared to group I, and these changes were more marked in hippocampus than frontal cortex. These changes correlated with respective free tissue Cu, oxidative stress, and Y-maze attention score. Cu toxicity induces apoptosis and astrocytosis of the hippocampus and frontal cortex through direct or glutamate and oxidative stress pathways, and results in impaired memory and learning.

Optimizing the Readout of Lanthanide-DOTA Complexes for the Detection of Ligand-Bound Copper(I)

The CuAAC ‘click’ reaction was used to couple alkyne-functionalized lanthanide-DOTA complexes to a range of fluorescent antennae. Screening of the antenna components was aided by comparison of the luminescent output of the resultant sensors using data normalized to account for reaction conversion as assessed by IR. A maximum 82-fold enhanced signal:background luminescence output was achieved using a Eu(III)-DOTA complex coupled to a coumarin-azide, in a reaction which is specific to the presence of copper(I). This optimized complex provides a new lead design for lanthanide-DOTA complexes which can act as irreversible ‘turn-on’ catalytic sensors for the detection of ligand-bound copper(I).

Social cognition in Wilson's disease: A new phenotype?

Studies focusing on neuropsychological impairments in Wilson’s disease (WD) have highlighted that patients showing neurological signs present significant deficits in a wide range of cognitive domains. Attentional and executive impairments have also been described in people with hepatic WD. However, social cognition abilities, i.e. cognitive processes required to perceive the emotions, intentions and dispositions of other people, have not been clearly investigated in WD. In this study we examined the social cognitive functioning in 19 patients with WD depending on their clinical status–Neurological versus Non-Neurological (“hepatic”) forms–compared to 20 healthy controls. For the very first time, results highlighted that patients with WD had significant impairments in the three major components of social cognition: emotion recognition, Theory of Mind and attributional style. However, these deficits differ depending on the form of the disease: patients with neurological signs showed a wide range of deficits in the three components that were assessed–results notably revealed impairments in recognizing “fear”, “anger”, and “disgust”, a significant Theory of Mind deficit and an “aggression bias”–whereas Non-Neurological patients only showed deficits on test assessing attributional bias, with a trend to react more “aggressively” to ambiguous social situations than healthy controls, as observed in Neurological WD patients, and a specific impairment in “anger” recognition. Our findings are discussed in the light of both neurocognitive impairments and brain damages, and especially those affecting the basal ganglia, as observed in people with WD.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Metal-Based Combinations That Target Protein Synthesis by Fungi

A wide range of fungicides (or antifungals) are used in agriculture and medicine, with activities against a spectrum of fungal pathogens. Unfortunately, the evolution of fungicide resistance has become a major issue. Therefore, there is an urgent need for new antifungal treatments. Certain metals have been used for decades as efficient fungicides in agriculture. However, concerns over metal toxicity have escalated over this time. Recent studies have revealed that metals like copper and chromate can impair functions required for the fidelity of protein synthesis in fungi. This occurs through different mechanisms, based on targeting of iron-sulphur cluster integrity or competition for uptake with amino acid precursors. Moreover, chromate at least acts synergistically with other agents known to target translation fidelity, like aminoglycoside antibiotics, causing dramatic and selective growth inhibition of several fungal pathogens of humans and plants. As such synergy allows the application of decreased amounts of metals for effective inhibition, it lessens concerns about nonspecific toxicity and opens new possibilities for metal applications in combinatorial fungicides targeting protein synthesis.

Neurological Complications of Nutritional Disease

Vitamins and minerals have essential functions in the body, from signal transduction to acting as cofactors for numerous enzymatic processes. Nutritional deficiencies and excess of certain vitamins and minerals can have profound effects on the central and peripheral nervous systems from early development into adulthood. This article summarizes the role of various nutritional factors in the nervous system and the neurological symptoms that can arise from deficiency or excess.

Restless legs syndrome in Wilson's disease: frequency, characteristics, and mimics

OBJECTIVE

To determine characteristics, clinical significance, frequency, and mimics of restless legs syndrome (RLS) in a cohort of Wilson's disease (WD, n = 42/f = 18), compared to healthy, matched controls.

MATERIALS AND METHODS

Structured clinical interviews (patients and caregiving family members), repeated neurological examinations (afternoon and presleep), comprehensive laboratory tests, WD-, RLS-, and sleep-specific rating scales, and video-polysomnography.

RESULTS

Thirteen patients with WD (13/42 = 31.0%) clearly fulfilled the five diagnostic criteria of RLS; in eight patients (19.1%), the burden of RLS was clinically significant. The RLS was of moderate severity, equally distributed among sexes, manifested mainly in the evening and before falling asleep, and had developed mostly after clinical manifestation of WD (time elapsed 10.2 ± 14.5 years), still at a young mean age (27.5 ± 11.5 years). The known RLS-associated features were absent (normal iron and kidney parameters) or rare (positive family history, polyneuropathy). Compared to WD patients without RLS, patients with RLS were significantly elder and had suffered longer from WD. WD-specific RLS mimics as well as RLS confounding motor comorbidities (dystonia, tremor, chorea) were frequent and a diagnostic challenge; in difficult cases, the differentiation was reached by clinical observation of the motor behavior in the evening or at nighttime.

CONCLUSION

RLS was frequent in this cohort of WD and might be causally related to WD. RLS should be included in the diagnostic work-up of WD. In complex motor disorders, differential diagnosis of RLS might require evening/nighttime examination and video-polysomnography. In WD patients with a clinically significant RLS, treatment with dopaminergic substances may be considered.

Occupancy of the Zinc-binding Site by Transition Metals Decreases the Substrate Affinity of the Human Dopamine Transporter by an Allosteric Mechanism

The human dopamine transporter (DAT) has a tetrahedral Zn²⁺-binding site. Zn²⁺-binding sites are also recognized by other first-row transition metals. Excessive accumulation of manganese or of copper can lead to parkinsonism because of dopamine deficiency. Accordingly, we examined the effect of Mn²⁺, Co²⁺, Ni²⁺, and Cu²⁺ on transport-associated currents through DAT and DAT-H193K, a mutant with a disrupted Zn²⁺-binding site. All transition metals except Mn²⁺ modulated the transport cycle of wild-type DAT with affinities in the low micromolar range. In this concentration range, they were devoid of any action on DAT-H193K. The active transition metals reduced the affinity of DAT for dopamine. The affinity shift was most pronounced for Cu²⁺, followed by Ni²⁺ and Zn²⁺ (= Co²⁺). The extent of the affinity shift and the reciprocal effect of substrate on metal affinity accounted for the different modes of action: Ni²⁺ and Cu²⁺ uniformly stimulated and inhibited, respectively, the substrate-induced steady-state currents through DAT. In contrast, Zn²⁺ elicited biphasic effects on transport, i.e. stimulation at 1 μm and inhibition at 10 μm. A kinetic model that posited preferential binding of transition metal ions to the outward-facing apo state of DAT and a reciprocal interaction of dopamine and transition metals recapitulated all experimental findings. Allosteric activation of DAT via the Zn²⁺-binding site may be of interest to restore transport in loss-of-function mutants.

Recent Updates on Acquired Hepatocerebral Degeneration

BACKGROUND

Acquired hepatocerebral degeneration (AHD) refers to a chronic neurological syndrome in patients with advanced hepatobiliary diseases. This comprehensive review focuses on the pathomechanism and neuroimaging findings in AHD.

METHODS

A PubMed search was performed using the terms "acquired hepatocerebral degeneration," "chronic hepatocerebral degeneration," "Non-Wilsonian hepatocerebral degeneration," "cirrhosis-related parkinsonism," and "manganese and liver disease."

RESULTS

Multiple mechanisms involving the accumulation of toxic substances such as ammonia or manganese and neuroinflammation may lead to widespread neurodegeneration in AHD. Clinical characteristics include movement disorders, mainly parkinsonism and ataxia-plus syndrome, as well as cognitive impairment with psychiatric features. Neuroimaging studies of AHD with parkinsonism show hyperintensity in the bilateral globus pallidus on T1-weighted magnetic resonance images, whereas molecular imaging of the presynaptic dopaminergic system shows variable findings. Ataxia-plus syndrome in AHD may demonstrate high-signal lesions in the middle cerebellar peduncles on T2-weighted images.

DISCUSSION

Future studies are needed to elucidate the exact pathomechanism and neuroimaging findings of this heterogeneous syndrome.

Neurotoxicity of Copper

Copper is an essential trace metal that is required for several important biological processes, however, an excess of copper can be toxic to cells. Therefore, systemic and cellular copper homeostasis is tightly regulated, but dysregulation of copper homeostasis may occur in disease states, resulting either in copper deficiency or copper overload and toxicity. This chapter will give an overview on the biological roles of copper and of the mechanisms involved in copper uptake, storage, and distribution. In addition, we will describe potential mechanisms of the cellular toxicity of copper and copper oxide nanoparticles. Finally, we will summarize the current knowledge on the connection of copper toxicity with neurodegenerative diseases.

The genetics of Wilson disease

Wilson disease (WD) is an autosomal-recessive disorder of hepatocellular copper deposition caused by pathogenic variants in the copper-transporting gene, ATP7B. Early detection and treatment are critical to prevent lifelong neuropsychiatric, hepatic, and systemic disabilities. Due to the marked heterogeneity in age of onset and clinical presentation, the diagnosis of Wilson disease remains challenging to physicians today. Direct sequencing of the ATP7B gene is the most sensitive and widely used confirmatory testing method, and concurrent biochemical testing improves diagnostic accuracy. More than 600 pathogenic variants in ATP7B have been identified, with single-nucleotide missense and nonsense mutations being the most common, followed by insertions/deletions, and, rarely, splice site mutations. The prevalence of Wilson disease varies by geographic region, with higher frequency of certain mutations occurring in specific ethnic groups. Wilson disease has poor genotype-phenotype correlation, although a few possible modifiers have been proposed. Improving molecular genetic studies continue to advance our understanding of the pathogenesis, diagnosis, and screening for Wilson disease.

Photocontrollable fluorogenic probes for visualising near-membrane copper(ii) in live cells

Photocontrollable fluorogenic probes for detecting near-membrane copper(ii) after membrane anchoring using spatial and temporal controlled release.

C–H oxidation and chelation of a dipyrromethane mediated rapid colorimetric naked-eye Cu(ii) chemosensor

Selective C–H oxidation and chelation of DPMs mediated by copper is demonstrated and utilized in the development of a rapid colorimetric naked-eye Cu(ii) chemosensor.

Manganese and the Insulin-IGF Signaling Network in Huntington's Disease and Other Neurodegenerative Disorders

Huntington's disease (HD) is an autosomal dominant neurodegenerative disease resulting in motor impairment and death in patients. Recently, several studies have demonstrated insulin or insulin-like growth factor (IGF) treatment in models of HD, resulting in potent amelioration of HD phenotypes via modulation of the PI3K/AKT/mTOR pathways. Administration of IGF and insulin can rescue microtubule transport, metabolic function, and autophagy defects, resulting in clearance of Huntingtin (HTT) aggregates, restoration of mitochondrial function, amelioration of motor abnormalities, and enhanced survival. Manganese (Mn) is an essential metal to all biological systems but, in excess, can be toxic. Interestingly, several studies have revealed the insulin-mimetic effects of Mn-demonstrating Mn can activate several of the same metabolic kinases and increase peripheral and neuronal insulin and IGF-1 levels in rodent models. Separate studies have shown mouse and human striatal neuroprogenitor cell (NPC) models exhibit a deficit in cellular Mn uptake, indicative of a Mn deficiency. Furthermore, evidence from the literature reveals a striking overlap between cellular consequences of Mn deficiency (i.e., impaired function of Mn-dependent enzymes) and known HD endophenotypes including excitotoxicity, increased reactive oxygen species (ROS) accumulation, and decreased mitochondrial function. Here we review published evidence supporting a hypothesis that (1) the potent effect of IGF or insulin treatment on HD models, (2) the insulin-mimetic effects of Mn, and (3) the newly discovered Mn-dependent perturbations in HD may all be functionally related. Together, this review will present the intriguing possibility that intricate regulatory cross-talk exists between Mn biology and/or toxicology and the insulin/IGF signaling pathways which may be deeply connected to HD pathology and, perhaps, other neurodegenerative diseases (NDDs) and other neuropathological conditions.

Visible detection of copper ions using a fluorescent probe based on red carbon dots and zirconium metal–organic frameworks

Specific spectral energy transfer leads to a gradually increasing quenching effect on the fluorescence of UiO-66-(COOH)₂with a higher concentration of Cu²⁺, causing a visible color change from blue to red.

Coexistence of Copper in the Iron-Rich Particles of Aceruloplasminemia Brain

The interaction between iron and copper has been discussed in association with human health and diseases for many years. Ceruloplasmin, a multi-copper oxidase, is mainly involved in iron metabolism and its genetic defect, aceruloplasminemia (ACP), shows neurological disorders and diabetes associated with excessive iron accumulation, but little is known about the state of copper in the brain. Here, we investigated localization of these metals in the brains of three patients with ACP using electron microscopes equipped with an energy-dispersive x-ray analyzer. Histochemically, iron deposition was observed mainly in the basal ganglia and dentate nucleus, and to lesser degree in the cerebral cortex of the patients, whereas copper grains were not detected. X-ray microanalysis identified two types of iron-rich particles in their brains: dense bodies, namely hemosiderins, and their aggregated inclusions. A small number of hemosiderins and most inclusions contained a significant amount of copper which was enough for distinct Cu x-ray images. These copper-containing particles were observed more frequently in the putamen and dentate nucleus than the cerebral cortex. Coexistence of iron and copper was supported by good correlations in the molecular ratios between these two metals in iron-rich particles with Cu x-ray image. Iron-dependent copper accumulation in iron-rich particles may suggest that copper recycling is enhanced to meet the increased requirement of cuproproteins in iron overload brain. In conclusion, the iron-rich particles with Cu x-ray image were found in the ACP brain.

Computational modelling of the redistribution of copper isotopes by proteins in the liver

The copper isotopic composition of blood serum as the mass balance of the copper isotopic composition of serum proteins.