MAMMALIAN COPPER HOMEOSTASIS: PHYSIOLOGIC ROLES AND MOLECULAR MECHANISMS.

In the past decade, evidence for numerous roles of copper (Cu) in mammalian physiology has grown exponentially. The discoveries of Cu involvement in cell signaling, autophagy, cell motility, differentiation, and regulated cell death (cuproptosis) have markedly extended the list of already known functions of Cu, such as a cofactor of essential metabolic enzymes, a protein structural component, and a regulator of protein trafficking. Novel and unexpected functions of Cu transporting proteins and enzymes have been identified, and new disorders of Cu homeostasis have been described. Significant progress has been made in the mechanistic studies of two classic disorders of Cu metabolism, Menkes disease and Wilson disease, which paved ways to novel approaches to their treatment. Discovery of cuproptosis and the role of Cu in cells metastatic growth have markedly increased interest in targeting Cu homeostatic pathways to treat cancer. In this review, we summarize the established concepts in the field of mammalian Cu physiology, and discuss how new discoveries of the past decade expand and modify these concepts. The roles of Cu in brain metabolism, in cells' functional speciation and a recently discovered regulated cell death have attracted significant attention and are highlighted in this review.

A new Caenorhabditis elegans model to study copper toxicity in Wilson disease.

Wilson disease (WD) is caused by mutations in the ATP7B gene that encodes a copper (Cu) transporting ATPase whose trafficking from the Golgi to endo-lysosomal compartments drives sequestration of excess Cu and its further excretion from hepatocytes into the bile. Loss of ATP7B function leads to toxic Cu overload in the liver and subsequently in the brain, causing fatal hepatic and neurological abnormalities. The limitations of existing WD therapies call for the development of new therapeutic approaches, which require an amenable animal model system for screening and validation of drugs and molecular targets. To achieve this objective, we generated a mutant Caenorhabditis elegans strain with a substitution of a conserved histidine (H828Q) in the ATP7B ortholog cua-1 corresponding to the most common ATP7B variant (H1069Q) that causes WD. cua-1 mutant animals exhibited very poor resistance to Cu compared to the wild-type strain. This manifested in a strong delay in larval development, a shorter lifespan, impaired motility, oxidative stress pathway activation, and mitochondrial damage. In addition, morphological analysis revealed several neuronal abnormalities in cua-1 mutant animals exposed to Cu. Further investigation suggested that mutant CUA-1 is retained and degraded in the endoplasmic reticulum, similarly to human ATP7B-H1069Q. As a consequence, the mutant protein does not allow animals to counteract Cu toxicity. Notably, pharmacological correctors of ATP7B-H1069Q reduced Cu toxicity in cua-1 mutants indicating that similar pathogenic molecular pathways might be activated by the H/Q substitution and, therefore, targeted for rescue of ATP7B/CUA-1 function. Taken together, our findings suggest that the newly generated cua-1 mutant strain represents an excellent model for Cu toxicity studies in WD.

α-lipoic acid ameliorates consequences of copper overload by up-regulating selenoproteins and decreasing redox misbalance.

α-lipoic acid (LA) is an essential cofactor for mitochondrial dehydrogenases and is required for cell growth, metabolic fuel production, and antioxidant defense. In vitro, LA binds copper (Cu) with high affinity and as an endogenous membrane permeable metabolite could be advantageous in mitigating the consequences of Cu overload in human diseases. We tested this hypothesis in 3T3-L1 preadipocytes with inactivated Cu transporter Atp7a; these cells accumulate Cu and show morphologic changes and mitochondria impairment. Treatment with LA corrected the morphology of Atp7a-/- cells similar to the Cu chelator bathocuproinedisulfonate (BCS) and improved mitochondria function; however, the mechanisms of LA and BCS action were different. Unlike BCS, LA did not decrease intracellular Cu but instead increased selenium levels that were low in Atp7a-/- cells. Proteome analysis confirmed distinct cell responses to these compounds and identified upregulation of selenoproteins as the major effect of LA on preadipocytes. Upregulation of selenoproteins was associated with an improved GSH:GSSG ratio in cellular compartments, which was lowered by elevated Cu, and reversal of protein oxidation. Thus, LA diminishes toxic effects of elevated Cu by improving cellular redox environment. We also show that selenium levels are decreased in tissues of a Wilson disease animal model, especially in the liver, making LA an attractive candidate for supplemental treatment of this disease.

Copper-independent lysosomal localisation of the Wilson disease protein ATP7B.

In hepatocytes, the Wilson disease protein ATP7B resides on the trans-Golgi network (TGN) and traffics to peripheral lysosomes to export excess intracellular copper through lysosomal exocytosis. We found that in basal copper or even upon copper chelation, a significant amount of ATP7B persists in the endolysosomal compartment of hepatocytes but not in non-hepatic cells. These ATP7B-harbouring lysosomes lie in close proximity of ~10 nm to the TGN. ATP7B constitutively distributes itself between the sub-domain of the TGN with a lower pH and the TGN-proximal lysosomal compartments. The presence of ATP7B on TGN-lysosome colocalising sites upon Golgi disruption suggested a possible exchange of ATP7B directly between the TGN and its proximal lysosomes. Manipulating lysosomal positioning significantly alters the localisation of ATP7B in the cell. Contrary to previous understanding, we found that upon copper chelation in a copper-replete hepatocyte, ATP7B is not retrieved back to TGN from peripheral lysosomes; rather, ATP7B recycles to these TGN-proximal lysosomes to initiate the next cycle of copper transport. We report a hitherto unknown copper-independent lysosomal localisation of ATP7B and the importance of TGN-proximal lysosomes but not TGN as the terminal acceptor organelle of ATP7B in its retrograde pathway.

Gandouling ameliorates liver injury in Wilson's disease through the inhibition of ferroptosis by regulating the HSF1/HSPB1 pathway.

Ferroptosis, an iron-dependent form of cell death, plays a crucial role in the progression of liver injury in Wilson's disease (WD). Gandouling (GDL) has emerged as a potential therapeutic agent for preventing and treating liver injury in WD. However, the precise mechanisms by which GDL mitigates ferroptosis in WD liver injury remain unclear. In this study, we discovered that treating Toxic Milk (TX) mice with GDL effectively decreased liver copper content, corrected iron homeostasis imbalances, and lowered lipid peroxidation levels, thereby preventing ferroptosis and improving liver injury. Bioinformatics analysis and machine learning algorithms identified Hspb1 as a pivotal regulator of ferroptosis. GDL treatment significantly upregulated the expression of HSPB1 and its upstream regulatory factor HSF1, thereby activating the HSF1/HSPB1 pathway. Importantly, inhibition of this pathway by NXP800 reversed the protective effects of GDL on ferroptosis in the liver of TX mice. In conclusion, GDL shows promise in alleviating liver injury in WD by inhibiting ferroptosis through modulation of the HSF1/HSPB1 pathway, suggesting its potential as a novel therapeutic agent for treating liver ferroptosis in WD.

Topographical metal burden correlates with brain atrophy and clinical severity in Wilson's disease.

BACKGROUND: Quantitative susceptibility mapping (QSM) is a post-processing technique that creates brain susceptibility maps reflecting metal burden through tissue magnetic susceptibility. We assessed topographic differences in magnetic susceptibility between participants with and without Wilson's disease (WD), correlating these findings with clinical severity, brain volume, and biofluid copper and iron indices. METHODS: A total of 43 patients with WD and 20 unaffected controls, were recruited. QSM images were derived from a 3T MRI scanner. Clinical severity was defined using the minimal Unified Wilson's Disease Rating Scale (M-UWDRS) and Montreal Cognitive Assessment scoring. Differences in magnetic susceptibilities between groups were evaluated using general linear regression models, adjusting for age and sex. Correlations between the susceptibilities and clinical scores were analyzed using Spearman's method. RESULTS: In age- and sex-adjusted analyses, magnetic susceptibility values were increased in WD patients compared with controls, including caudate nucleus, putamen, globus pallidus, and substantia nigra (all p < 0.01). Putaminal susceptibility was greater with an initial neuropsychiatric presentation (n = 25) than with initial hepatic dysfunction (n = 18; p = 0.04). Susceptibility changes correlated negatively with regional brain volume in almost all topographic regions. Serum ferritin, but not serum copper or ceruloplasmin, correlated positively with magnetic susceptibility level in the caudate nucleus (p = 0.04), putamen (p = 0.04) and the hippocampus (p = 0.03). The dominance of magnetic susceptibility in cortical over subcortical regions correlated with M-UWDRS scores (p < 0.01). CONCLUSION: The magnetic susceptibility changes could serve as a surrogate marker for patients with WD.

FoxO1 silencing in Atp7b-/- neural stem cells attenuates high copper-induced apoptosis via regulation of autophagy.

Wilson disease (WD) is a severely autosomal genetic disorder triggered by dysregulated copper metabolism. Autophagy and apoptosis share common modulators that process cellular death. Emerging evidences suggest that Forkhead Box O1 over-expression (FoxO1-OE) aggravates abnormal autophagy and apoptosis to induce neuronal injury. However, the underlying mechanisms remain undetermined. Herein, the aim of this study was to investigate how regulating FoxO1 affects cellular autophagy and apoptosis to attenuate neuronal injury in a well-established WD cell model, the high concentration copper sulfate (CuSO4, HC)-triggered Atp7b-/- (Knockout, KO) neural stem cell (NSC) lines. The FoxO1-OE plasmid, or siRNA-FoxO1 (siFoxO1) plasmid, or empty vector plasmid was stably transfected with recombinant lentiviral vectors into HC-induced Atp7b-/- NSCs. Toxic effects of excess deposited copper on wild-type (WT), Atp7b-/- WD mouse hippocampal NSCs were tested by Cell Counting Kit-8 (CCK-8). Subsequently, the FoxO1 expression was evaluated by immunofluorescence (IF) assay, western blot (WB) and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. Meanwhile, the cell autophagy and apoptosis were evaluated by flow cytometry (FC), TUNEL staining, 2,7-dichlorofluorescein diacetate (DCFH-DA), JC-1, WB, and qRT-PCR. The current study demonstrated a strong rise in FoxO1 levels in HC-treated Atp7b-/- NSCs, accompanied with dysregulated autophagy and hyperactive apoptosis. Also, it was observed that cell viability was significantly decreased with the over-expressed FoxO1 in HC-treated Atp7b-/- WD model. As intended, silencing FoxO1 effectively inhibited abnormal autophagy in HC-treated Atp7b-/- NSCs, as depicted by a decline in LC3II/I, Beclin-1, ATG3, ATG7, ATG13, and ATG16, whereas simultaneously increasing P62. In addition, silencing FoxO1 suppressed apoptosis via diminishing oxidative stress (OS), and mitochondrial dysfunction in HC-induced Atp7b-/- NSCs. Collectively, these results clearly demonstrate the silencing FoxO1 has the neuroprotective role of suppressing aberrant cellular autophagy and apoptosis, which efficiently attenuates neuronal injury in WD.

Altered cortical functional networks in Wilson's disease: A resting-state electroencephalogram study.

The neuropsychiatric symptoms are common in Wilson's disease (WD) patients. However, it remains unclear about the associated functional brain networks. In this study, source localization-based functional connectivity analysis of close-eye resting-state electroencephalography (EEG) were implemented to assess the characteristics of functional networks in 17 WD patients with neurological involvements and 17 healthy controls (HCs). The weighted phase-lag index (wPLI) was subsequently calculated in source space across five different frequency bands and the resulting connectivity matrix was transformed into a weighted graph whose structure was measured by five graphical analysis indicators, which were finally correlated with clinical scores. Compared to HCs, WD patients revealed disconnected sub-networks in delta, theta and alpha bands. Moreover, WD patients exhibited significantly reduced global clustering coefficients and small-worldness in all five frequency bands. In WD group, the severity of neurological symptoms and structural brain abnormalities were significantly correlated with disrupted functional networks. In conclusion, our study demonstrated that functional network deficits in WD can reflect the severity of their neurological symptoms and structural brain abnormalities. Resting-state EEG may be used as a marker of brain injury in WD.

Obesity as a Confounding Factor in the Diagnosis of Wilson's Disease: Case Report of Two Siblings with the Same Genotype but Different Clinical Courses.

Wilson's disease (WD) is a biallelic disease-causing variant in the ATP7B gene on chromosome 13q14.3 that results in copper accumulation in many organs, particularly the liver and brain. The phenotypic spectrum is wide and symptoms at onset can be heterogeneous. We describe two Sicilian siblings, a young man and his elder sister, both compound heterozygous for the variants c.1286-2A>G and c.2668G>A (p.Val890Met) in the ATB7B gene. The male patient presented with liver cirrhosis, which quickly progressed to end-stage liver disease (Child-Pugh score = C10), while his sister had moderate steatotic liver disease (SLD). Our findings highlight that SLD may not always be related to obesity in overweight patients, especially when there are other potential risk factors such as a family history of chronic liver disease, or the persistence of high transaminase despite the adoption of adequate dietary and pharmacological intervention. Screening for conditions such as WD could identify patients at risk of developing SLD and avoid delays in diagnosis. Phenotypic variability in WD is considerable; therefore, further studies are needed to identify which WD patients have a greater risk of developing SLD and determine factors that can predict the severity of the disease.

ARBM101 (Methanobactin SB2) Drains Excess Liver Copper via Biliary Excretion in Wilson's Disease Rats.

BACKGROUND & AIMS: Excess copper causes hepatocyte death in hereditary Wilson's disease (WD). Current WD treatments by copper-binding chelators may gradually reduce copper overload; they fail, however, to bring hepatic copper close to normal physiological levels. Consequently, lifelong daily dose regimens are required to hinder disease progression. This may result in severe issues due to nonadherence or unwanted adverse drug reactions and also due to drug switching and ultimate treatment failures. This study comparatively tested bacteria-derived copper binding agents-methanobactins (MBs)-for efficient liver copper depletion in WD rats as well as their safety and effect duration. METHODS: Copper chelators were tested in vitro and in vivo in WD rats. Metabolic cage housing allowed the accurate assessment of animal copper balances and long-term experiments related to the determination of minimal treatment phases. RESULTS: We found that copper-binding ARBM101 (previously known as MB-SB2) depletes WD rat liver copper dose dependently via fecal excretion down to normal physiological levels within 8 days, superseding the need for continuous treatment. Consequently, we developed a new treatment consisting of repetitive cycles, each of ∼1 week of ARBM101 applications, followed by months of in-between treatment pauses to ensure a healthy long-term survival in WD rats. CONCLUSIONS: ARBM101 safely and efficiently depletes excess liver copper from WD rats, thus allowing for short treatment periods as well as prolonged in-between rest periods.

Aberrant copper metabolism and hepatic inflammation cause neurological manifestations in a mouse model of Wilson's disease.

Pathogenic germline mutations in the P-type copper-transporting ATPase (ATP7B) gene cause Wilson's disease (WD), a hereditary disorder characterized by disrupted copper metabolism. The Arg778Leu (R778L) mutation in exon 8 is prevalent among individuals with WD in East Asia and is associated with more severe phenotypes. In this study, we generated a WD mouse model harboring R778L mutation (R778L mice) using CRISPR/Cas9. R778L mice exhibit a range of pathological characteristics resembling those of patients with WD and the same point mutations, including aberrant copper metabolism, pathological cellular injury, inflammation, and severe hepatic fibrosis. At 3-5 months of age, these mice started to display neurological deficits in motor coordination and cognitive dysfunction, accompanied by increased expression of inflammatory cytokines in the central nervous system. Microglia in the striatum and cortex exhibit significant activation, shorter processes, and decreased branch points. However, the Cu2+ levels in the brain tissue of R778L mice did not differ significantly from those of wild-type mice. Notably, inhibition of hepatic inflammation with PJ34 or siNfkb markedly alleviated the deficiencies in cognitive performance and improved locomotor activity in R778L mice. Thus, this study establishes a novel murine model to investigate the pathophysiology of WD, highlights the liver-brain crosstalk responsible for neurological manifestations in individuals with WD caused by the R778L point mutation, and demonstrates the potential of modulating liver inflammation as a therapeutic strategy for alleviating the neurological manifestations of WD.

From Wilson's Disease to Neurodevelopmental Disorder with Involuntary Movements, Different Genetic Interpretations in a Female Patient.

BACKGROUND: A 19-year-old female patient presented at 2 years of age with dysarthria, incoherent speech, and unsteady ambulation. She is prone to leaning backward when walking and has involuntary movements of the whole body. Besides, she has poor numeracy skills. She has been diagnosed with Wilson's disease (WD) in China and Japan. OBJECTIVE: The objective of this study was to further clarify the diagnosis of this patient. METHODS: The patient and her parents were detected with whole-exome sequencing. RESULTS: Based on the genetic test results, genetic analyses, and clinical manifestations, a diagnosis of WD in this patient was ruled out. The patient was eventually diagnosed with neurodevelopmental disorder with involuntary movements. CONCLUSIONS: This study reinterprets the genetic test results of a young female patient and leads to reflections on the genetic diagnostic criteria for WD: the Leipzig score is suitable for the diagnosis of most WD patients, and the genetic testing section of the score is of great diagnostic value. However, in some special cases, the proband and their first-degree relatives should further complete cosegregation analysis to determine the origin of the lesion gene and to verify the reliability of the genetic test. In addition, this study suggests that further improving the scoring rules of the gene testing part of the Leipzig scoring system may be more helpful in achieving an accurate diagnosis of WD. © 2024 International Parkinson and Movement Disorder Society.

Diagnosing aceruloplasminemia: navigating through red herrings.

A 58-year-old female was found to have hyperferritinemia (Serum ferritin:1683 ng/mL) during work-up for mild normocytic anemia. Transferrin saturation(TSAT) was low-normal. Magnetic resonance imaging (MRI) abdomen showed evidence of hepatic iron deposition. Liver biopsy showed 4 + hepatic iron deposition without any evidence of steatosis or fibrosis. Quantitative liver iron was elevated at 348.3 µmol/g dry liver weight [Reference range(RR): 3-33 µmol/g dry liver weight]. She was presumptively diagnosed with tissue iron overload, cause uncertain. A diagnosis of ferroportin disease (FD) was considered, but the pattern of iron distribution in the liver, mainly within the hepatic parenchyma (rather than in the hepatic Kupffer cells seen in FD), and the presence of anemia (uncommon in FD) made this less likely. She was treated with intermittent phlebotomy for over a decade with poor tolerance due to worsening normocytic to microcytic anemia. A trial of deferasirox was done but it was discontinued after a month due to significant side effects. During the course of treatment, her ferritin level decreased. Over the past 1.5 years, she developed progressively worsening neurocognitive decline. MRI brain showed areas of susceptibility involving basal ganglia, midbrain and cerebellum raising suspicion for metabolic deposition disease. Neuroimaging findings led to testing for serum copper and ceruloplasmin levels which were both found to be severely low. Low serum copper, ceruloplasmin levels and neuroimaging findings led us to consider Wilson disease however prior liver biopsy showing elevated hepatic iron rather than hepatic copper excluded the diagnosis of Wilson disease. After shared decision making, ceruloplasmin gene analysis was not pursued due to patient's preference and prohibitive cost of testing. The diagnosis of aceruloplasminemia was ultimately made. The biochemical triad of hyperferritinemia, low-normal TSAT and microcytic anemia should raise the possibility of aceruloplasminemia. Since neurological manifestations are rare in most inherited iron overload syndromes, neurological symptoms in a patient with tissue iron overload should prompt consideration of aceruloplasminemia as a differential diagnosis.

Adverse pregnancy outcomes and effect of treatment in Wilson disease during pregnancy: Systematic review and meta-analysis.

BACKGROUND AND AIMS: Wilson disease (WD) is a rare disorder of copper metabolism, leading to liver and neurological disease. Existing literature on WD in pregnancy is scarce, limiting preconception and obstetrical counselling. In this systematic review with meta-analysis, we determine the prevalence of various adverse pregnancy and neonatal outcomes in WD, as well as evaluate the impact of WD treatment on these outcomes. METHODS: Scopus, MEDLINE and EMBASE were searched until 12 May 2023, for studies of pregnant individuals with WD and at least one pregnancy or neonatal outcome of interest. Meta-analysis of single proportions was conducted to pool prevalence data for each outcome. Outcome rates were compared between treated and untreated groups in a meta-analysis of dichotomous events. RESULTS: Sixteen studies, published from 1975 to 2022, were included in the systematic review. Thirty-seven percent of pregnancies reported at least one adverse pregnancy outcome. Spontaneous abortions (20%), liver diseases of pregnancy (4.5%) and preterm births (2%) were the most frequent adverse pregnancy outcomes in patients with WD. The prevalence of spontaneous abortions was significantly lower in pregnant individuals with WD who received treatment during pregnancy (OR: .47, 95% CI: 35%-63%). The prevalence of any adverse pregnancy outcome was also significantly lower with treatment (OR: .53, 95% CI: .37-.76), which appears to be mostly driven by the reduction of spontaneous abortions. CONCLUSIONS: There is low to moderate quality evidence to suggest that preconception and obstetrical counselling for patients with WD should include a discussion on the potentially high frequency of adverse pregnancy outcomes in this population, as well as the importance of continuing WD treatment during pregnancy to ensure satisfactory pregnancy course and potentially minimize the risk of spontaneous abortions.

Clinical characteristics and prognosis of early diagnosed Wilson's disease: A large cohort study.

BACKGROUND AND AIMS: Few studies have focused on the outcomes of Wilson's disease (WD) diagnosed before age of 5 years. This study aimed to summarize the clinical features of early diagnosed WD and analyse treatment outcomes and the risk factors associated with treatment failure. METHODS: A total of 139 children confirmed with WD before 5 years were enrolled in this study. Only patients with follow-up over 1 year were analysed with Kaplan-Meier survival analysis. The composite outcomes included death, progression to liver failure or acute hepatitis, development of renal or neurological symptoms and persistent elevation of alanine aminotransferase (ALT). The treatment failure was defined as occurrence of at least one of above outcomes. RESULTS: Among 139 WD patients at diagnosis, two (1.4%) WD patients presented with symptomatic liver disease, whereas 137 (98.6%) were phenotypically asymptomatic, including 135 with elevated ALT and 2 with normal liver function. Median serum ceruloplasmin (Cp) was 3.1 mg/dL, and urinary copper excretion was 87.4 µg/24-h. There were 71 variants identified in the the copper-transporting ATPase beta gene, and 29 were loss of function (LOF). 51 patients with LOF variant were younger at diagnosis and had lower Cp than 88 patients without LOF. Among 93 patients with over 1 year of follow-up, 19 (20.4%) received zinc monotherapy, and 74 (79.6%) received a zinc/D-penicillamine combination therapy. 14 (15.1%) patients underwent treatment failure, and its occurrence was associated with poor compliance (p < .01). CONCLUSIONS: Cp is a reliable biomarker for early diagnosis, and zinc monotherapy is an effective treatment for WD during early childhood. Good treatment compliance is critical to achieve a favourable outcome.

A case of Wilson's disease combined with intracranial lipoma and dysplasia of the corpus callosum with review of the literature.

BACKGROUND: Wilson's disease (WD) is an inherited disorder of copper metabolism. Agenesis of the corpus callosum is the complete or partial absence of the major united fiber bundles connecting the cerebral hemispheres. Intracranial lipoma is an adipose tissue tumor resulting from an abnormal embryonic development of the central nervous system. The simultaneous occurrence of these three disorders is rare and has not been reported. This report focuses on the pathogenesis and association between the three disorders and highlights the importance of recognizing and effectively managing their coexistence. CASE PRESENTATION: The purpose of this study was to present a patient with coexisting WD, intracranial lipoma, and corpus callosum dysplasia. We reviewed a female patient hospitalized in 2023 with clinical manifestations of elevated aminotransferases and decreased ceruloplasmin, as well as genetic testing for an initial diagnosis of Wilson's disease. Subsequently, a cranial MRI showed corpus callosum dysplasia with short T1 signal changes in the cerebral falx, leading to a final diagnosis of Wilson's disease combined with intracranial lipoma and corpus callosum dysplasia. The patient's WD is currently stable after treatment with sodium dimercaptosulfonamide (DMPS) and penicillamine, and the patient's abnormal copper metabolism may promote the growth of intracranial lipoma. CONCLUSION: The pathogenesis of WD combined with intracranial lipoma and corpus callosum dysplasia is complex and clinically rare. The growth of intracranial lipomas may be associated with abnormal copper metabolism in WD. Abnormal copper metabolism affects lipid metabolism and triggers inflammatory responses. Therefore, early diagnosis and treatment are beneficial for improvement. Each new case of this rare co-morbidity is important as it allows for a better assessment and understanding of these cases' more characteristic clinical manifestations, which can help estimate the course of the disease and possible therapeutic options.

Accurate non-ceruloplasmin bound copper: a new biomarker for the assessment and monitoring of Wilson disease patients using HPLC coupled to ICP-MS/MS.

OBJECTIVES: Assessment of Wilson disease is complicated, with neither ceruloplasmin, nor serum or urine copper, being reliable. Two new indices, accurate non-ceruloplasmin copper (ANCC) and relative ANCC were developed and applied to a cohort of 71 patients, as part of a Wilson Disease Registry Study. METHODS: Elemental copper-protein speciation was developed for holo-ceruloplasmin quantitation using strong anion exchange chromatography coupled to triple quadrupole inductively coupled plasma mass spectrometry. The serum proteins were separated using gradient elution and measured at m/z 63 (63Cu+) and 48 (32S16O+) using oxygen reaction mode and Cu-EDTA as calibration standard. The ANCC was calculated by subtraction of the ceruloplasmin bound copper from the total serum copper and the RelANCC was the percentage of total copper present as the ANCC. RESULTS: The accuracy of the holo-ceruloplasmin measurement was established using two certified reference materials, giving a mean recovery of 94.2 %. Regression analysis between the sum of the copper containing species and total copper concentration in the patient samples was acceptable (slope=0.964, intercept=0, r=0.987) and a difference plot, gave a mean difference for copper of 0.38 µmol/L. Intra-day precision for holo-ceruloplasmin at serum copper concentrations of 0.48 and 3.20 µmol/L were 5.2 and 5.6 % CV and the intermediate precision at concentrations of 0.80 and 5.99 µmol/L were 6.4 and 6.4 % CV, respectively. The limit of detection (LOD) and lower limit of quantification (LLOQ) for holo-ceruloplasmin were 0.08 and 0.27 µmol/L as copper, respectively. CONCLUSIONS: ANCC and Relative ANCC are important new diagnostic and monitoring biomarker indices for Wilson disease (WD).

Transcriptomic evaluation of N6-methyladenosine modification can be used to identify differentially gene and immune-related biological processes in TX mice with liver fibrosis.

BACKGROUND: N6-methyladenosine (m6A) modification controls the stability, splicing, and translation of mRNA, which is important in the development of illnesses. Wilson's disease (WD) is an autosomal recessive liver copper metabolic disorder that causes liver fibrosis. The role of m6A methylation in WD-induced liver fibrosis development is still unclear. Thus, the goal of this study was to examine the scope of m6A methylation and further explore the potential targets related to WD-induced liver fibrosis. RESULTS: A total of 1930 significantly different m6A peaks were found on 1737 mRNAs, of which 993 were hypermethylated and 744 were hypomethylated when comparing normal and WD-induced liver fibrosis mice (n = 3). In parallel, 1261 differentially expressed mRNAs, comprising 557 upregulated and 704 downregulated mRNAs, were found. Overall, 114 mRNAs with significant changes in m6A levels and RNA expression were identified via joint analysis. Then, through PPI network construction and functional enrichment analysis, 12 hub genes were identified, these genes were mainly enriched in the inflammatory response and immunomodulation, and they are associated with immune cell infiltration. CONCLUSIONS: The significant difference in the amount of mRNA m6A modifications indicates that m6A modification is involved in the progression of WD-induced liver fibrosis, and theidentified hub genes are involved in inflammation and immune infiltration. These results may provide insights for subsequent studies on potential regulatory mechanisms.

Relapse following withdrawal of D-penicillamine from combination (D-penicillamine + zinc) therapy in hepatic Wilson disease.

OBJECTIVES: Long-term D-penicillamine (D-pen) therapy in Wilson disease (WD) has numerous adverse effects which advocates its withdrawal, but with an inherent risk of relapse. This prospective observational study was conducted with the objective of evaluating incidence of relapse following withdrawal of D-pen from combination (D-pen + zinc) therapy in maintenance phase of previously symptomatic hepatic WD. METHODS: Hepatic WD patients <18 years of age and on combination therapy for >2 years with 6 months of biochemical remission were included. Biochemical remission was defined as achievement of (i) aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤1.5 times upper limit of normal (ULN), (ii) serum albumin >3.5 g/dL, international normalized ratio (INR) <1.5 and (iii) 24-h urinary copper excretion (UCE) <500 mcg/day, nonceruloplasmin-bound-copper (NCC) <15 mcg/dL. After D-pen withdrawal, monthly liver function test (LFT) and INR and 3 monthly UCE and NCC were done till 1 year or relapse (elevation of AST/ALT/both >2 times ULN or total bilirubin >2 mg/dL), whichever occurred earlier. RESULTS: Forty-five patients enrolled with median combination therapy duration of 36 months. Sixty percent of them had their index presentation as decompensated cirrhosis. Fourteen patients (31.8%) relapsed (cumulative incidence: 4 at 3 months, 11 at 6 months, and 14 at 12 months after D-pen discontinuation). All relapsers had index presentation as decompensated cirrhosis. On Cox-regression, ALT at D-pen withdrawal was an independent predictor of relapse (hazard ratio [HR]: 1.077, 95% confidence interval [CI]: 1.014-1.145, p = 0.017) with area under the receiver operating characteristic (AUROC) of 0.860. ALT ≥40 U/L predicted risk of relapse with 85.7% sensitivity, 70.9% specificity. CONCLUSION: Incidence of relapse after withdrawal of D-pen from combination therapy is 31.8% in hepatic WD. ALT ≥40 U/L, at the time of D-pen stoppage, predicts future relapse.

Effect of primary copper metabolism disturbance on elemental, protein, and lipid composition of the organs in Jackson toxic milk mouse.

Toxic milk (txJ) is an autosomal recessive mutation in the Atp7b gene in the C3H/HeJ strain, observed at The Jackson Laboratory in Maine, USA. TxJ mice exhibit symptoms similar to those of human Wilson's disease (WD). The study aimed to verify organ involvement in a mouse model of WD. TxJ mice and control animals were sacrificed at 2, 4, 8, and 14 months of age. Total X-ray Fluorescence Spectroscopy (TXRF) was used to determine the elemental concentration in organs. Tissue chemical composition was measured by Fourier Transform Infrared Spectroscopy (FTIR). Additionally, hybrid mapping of FTIR and microXRF was performed. Elevated concentrations of Cu were observed in the liver, striatum, eye, heart, and duodenum of txJ mice across age groups. In the striatum of the oldest txJ mice, there was lower lipid content and a higher fraction of saturated fats. The secondary structure of striatum proteins was disturbed in txJ mice. In the livers of txJ mice, higher concentrations of saturated fats and disturbances in the secondary structure of proteins were observed. The concentration of neurofilaments was significantly higher in txJ serum. The distribution of Cu deposits in brains was uniform with no prevalence in any anatomic structure in either group, but significant protein structure changes were observed exclusively in the striatum of txJ. In this txJ animal model of WD, pathologic copper accumulation occurs in the duodenum, heart, and eye tissues. Increased copper concentration in the liver and brain results in increased saturated fat content and disturbances in secondary protein structure, leading to hepatic injury and neurodegeneration.