Efficacy and safety of oral chelators in treatment of patients with Wilson disease

Copper homeostasis and neurodegenerative diseases

Copper, one of the most prolific transition metals in the body, is required for normal brain physiological activity and allows various functions to work normally through its range of concentrations. Copper homeostasis is meticulously maintained through a complex network of copper-dependent proteins, including copper transporters (CTR1 and CTR2), the two copper ion transporters the Cu -transporting ATPase 1 (ATP7A) and Cu-transporting beta (ATP7B), and the three copper chaperones ATOX1, CCS, and COX17. Disruptions in copper homeostasis can lead to either the deficiency or accumulation of copper in brain tissue. Emerging evidence suggests that abnormal copper metabolism or copper binding to various proteins, including ceruloplasmin and metallothionein, is involved in the pathogenesis of neurodegenerative disorders. However, the exact mechanisms underlying these processes are not known. Copper is a potent oxidant that increases reactive oxygen species production and promotes oxidative stress. Elevated reactive oxygen species levels may further compromise mitochondrial integrity and cause mitochondrial dysfunction. Reactive oxygen species serve as key signaling molecules in copper-induced neuroinflammation, with elevated levels activating several critical inflammatory pathways. Additionally, copper can bind aberrantly to several neuronal proteins, including alpha-synuclein, tau, superoxide dismutase 1, and huntingtin, thereby inducing neurotoxicity and ultimately cell death. This study focuses on the latest literature evaluating the role of copper in neurodegenerative diseases, with a particular focus on copper-containing metalloenzymes and copper-binding proteins in the regulation of copper homeostasis and their involvement in neurodegenerative disease pathogenesis. By synthesizing the current findings on the functions of copper in oxidative stress, neuroinflammation, mitochondrial dysfunction, and protein misfolding, we aim to elucidate the mechanisms by which copper contributes to a wide range of hereditary and neuronal disorders, such as Wilson's disease, Menkes' disease, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis. Potential clinically significant therapeutic targets, including superoxide dismutase 1, D-penicillamine, and 5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline, along with their associated therapeutic agents, are further discussed. Ultimately, we collate evidence that copper homeostasis may function in the underlying etiology of several neurodegenerative diseases and offer novel insights into the potential prevention and treatment of these diseases based on copper homeostasis.

Advancements in diagnostic approaches for Wilson's disease

Wilson's disease (WD) is a genetic disorder that results in excessive copper build-up in tissues, causing significant liver and neurological damage. Early and accurate diagnosis is crucial for effective management and treatment. Traditional diagnostic methods, including serum ceruloplasmin and urinary copper level monitoring, liver biopsy and genetic testing, are limited by sensitivity, specificity, invasiveness, and accessibility. Recent advances in diagnostic technologies offer new hope for more accurate, rapid, and non-invasive detection of WD. In this regard, nanotechnology-driven formulations hold significant promise for both the early diagnosis and treatment of WD. Through the innovative use of advanced nanomaterials, researchers are developing more effective therapeutic options and highly sensitive diagnostic tools, potentially transforming the management and prognosis of this genetic disorder. This review provides a comprehensive analysis of recent advancements in WD diagnostics, focusing on research published since 2016. It explores the development and application of novel biomarkers, advanced imaging modalities, innovative biosensors, and emerging nanotechnology-based approaches. By integrating these cutting-edge methodologies, the review highlights their potential to enhance early and accurate detection of WD, addressing current diagnostic challenges and improving clinical outcomes.

N,N'-bis(2-mercaptoethyl)isophthalamide (NBMI) as a novel chelator for Wilson's disease

Wilson's Disease (WD) is a rare autosomal recessive disorder caused by mutations in the ATP7B gene. These mutations lead to defective copper (Cu) transport and to accumulation of Cu in tissues, primarily in the liver and brain. Current treatment options such as D-penicillamine, trientine, and zinc salts focus on increasing Cu excretion or reducing Cu absorption, but often cause debilitating side effects. N,N'-bis(2-mercaptoethyl)isophthalamide (NBMI) is a lipophilic thiol-based compound originally developed for environmental decontamination. It has been shown to chelate toxic metals such as mercury, lead, and cadmium. This study was designed to evaluate the efficacy of NBMI to mitigate Cu overload using both in vitro and in vivo models of WD. HepG2 cells with the ATP7B gene knocked down had increased sensitivity to copper sulfate (CuSO4) compared to wild-type (WT) cells, validating the cell model for WD. Pretreatment with NBMI (2.5-50 μM) improved cell viability, reduced Cu-induced oxidative stress, decreased metallothionein levels, mitigated resulting DNA damage, and reduced overall levels of free intracellular Cu. In an established toxic milk mouse (tx-J) model of WD, 1% dietary NBMI effectively lowered hepatic, cerebral, and renal Cu levels. Treatment with 1% NBMI also improved liver function, as evidenced by reduced ALT levels and normalized hepatocyte morphology. Tx-J mice displayed higher liver-to-body weight ratios compared to WT mice, and treatment with 1% NBMI effectively reduced this ratio. While NBMI did not impact the elevated white blood cell counts and low platelet levels characteristic of tx-J mice, it also did not cause any detrimental effects on red blood cell, hemoglobin, and hematocrit levels. This dose of NBMI also restored homeostasis of other dysregulated essential metal ions in tx-J mice. These findings suggest that dietary administration of NBMI effectively chelates excess free Cu, ameliorates WD symptoms and offers a promising alternative to existing chelators.

Emerging roles of cuproptosis in liver diseases

Intracellular copper levels should be maintained within a controlled range to obtain copper homeostasis. Cuproptosis, a newly discovered form of cell death, occurs when excessive copper ions bind to the lipoylated enzymes in the tricarboxylic acid cycle, which leads to lipoylated protein aggregation, proteotoxic stress, and ultimately cell death. Herein, we summarize the current knowledge regarding copper metabolism, the discovery and molecular mechanism of cuproptosis. In addition, we discuss the implications of cuproptosis in the pathogenesis of various liver diseases, including hepatocellular carcinoma (HCC), Wilson disease (WD), metabolic-associated fatty liver disease (MAFLD), liver fibrosis, hepatic ischemia-reperfusion injury (HIRI) and drug-induced liver injury (DILI). Understanding the mechanism of cuproptosis can not only provide deeper insights into the pathogenesis of liver diseases but also open up new avenues for the development of targeted therapies.

Practical and Multidisciplinary Review on Wilson Disease: The Portuguese Perspective

Wilson disease (WD) is a genetic disorder of copper metabolism caused by mutations in the ATP7B gene resulting in toxic copper accumulation in several organs. WD can manifest as liver disease, a progressive neurological disorder, a psychiatric illness, or a combination of these. Other clinical manifestations can also occur. Diagnosis is challenging and typically requires a range of biochemical tests, imaging, genetic testing for ATP7B, and/or liver biopsy. WD is treatable with chelating agents, such as d-penicillamine and trientine, and/or zinc salts alongside with dietary copper restriction. Liver transplantation may be indicated in WD patients with severe hepatic disease, and cautiously considered in patients with neurological WD. Treatment success highly depends on patient adherence and treatment persistence. Therefore, effective interventions for improving patient adherence and close monitoring are key for preventing WD progression. In Portugal, there are no reference centers for WD, and patients are dispersed across numerous medical specialists. This review aimed to summarize the most recent and relevant information for the diagnosis, treatment, and monitoring of WD in Portugal, as well as possible interventions for stimulating adherence to treatment.

Prospective Study to Assess Long-Term Outcomes of Chelator-Based Treatment With Trientine Dihydrochloride in Patients With Wilson Disease

Background and Aims

Wilson disease is an inherited disorder of copper metabolism affecting mainly the liver and brain. Trientine dihydrochloride (TETA-2HCl) is approved for the treatment of Wilson disease in patients (≥ 5 years) intolerant to D-penicillamine therapy. This study assessed the long-term outcomes of treatment with TETA-2HCl in Wilson disease patients.

Methods

In this Phase 2, prospective study, patients continued their treatment of TETA-2HCl 300 mg (200 mg trientine base) for 12 months (July 2015-April 2017) at one center in Germany. Primary outcomes were the safety and efficacy of TETA-2HCl treatment; Biomarkers of copper metabolism; and the course of hepatic and neurologic disease.

Results

Overall, 51 patients contributed data. Almost all patients (50 [98.0%]) were considered responders (rating of ≤ 4 at the 12-month visit); Unified Wilson Disease Rating Scale scores improved throughout the study from a mean (standard deviation) of 11.3 (24.31) at Baseline to 8.8 (22.86) at Month 12. Biochemical assessments of liver parameters (transaminases, liver synthesis) as well as markers of copper metabolism (24-h urinary copper, non-ceruloplasmin bound copper (NCC)) showed improved or stable disease throughout the study. Treatment-emergent adverse events were reported in five (9.6%) patients. No patients withdrew from treatment due to adverse events, and no serious adverse events were considered to be treatment-related.

Conclusions

This study demonstrated that treatment with TETA-2HCl was effective and well tolerated in hepatic and neurologic disease manifestations. Additionally, improvement in neurological symptoms was reported throughout the trial, suggesting that improvements may be reported for an extended period after initiation of therapy. Trial Registration: NCT02426905.

EASL-ERN Clinical Practice Guidelines on Wilson's disease

Wilson's disease is an autosomal recessive disorder of copper metabolism which affects the liver, brain and other organs. Diagnosis is based on: clinical features; biochemical tests, including plasma ceruloplasmin concentration, 24-h urinary copper excretion, copper content in the liver; and molecular analysis. Leipzig score and additionally relative exchangeable copper determination are recommended for diagnosis. Pharmacological therapy comprises chelating agents (penicillamine, trientine) and zinc salts, while only chelators are recommended for significant liver disease. Monitoring is based on clinical symptoms, liver tests and copper metabolism (urinary copper excretion, exchangeable copper) to detect poor compliance and over/under-treatment. Acute liver failure is challenging as making a diagnosis is difficult and pharmacological therapy may not be sufficient to save life. Liver transplantation has a well-defined role in Wilsonian acute hepatic failure but may also be considered in neurological disease.

D-Penicillamine Induced Myelotoxicity: A Unique Case

Purpose: A case of D-penicillamine-related myelotoxicity in a patient with Wilson's disease is reported. Summary: There is a paucity of literature regarding D-penicillamine (DPA) induced myelotoxicity in the setting of Wilson's disease (WD). A 22-year-old male presented with a 1-week history of bleeding gums and dizziness. Four months prior, he had been diagnosed with Wilson's disease and started on a regimen of DPA. His blood counts demonstrated profound pancytopenia. Due to concern for suspected drug-induced myelotoxicity, DPA was discontinued. Parvovirus B19, Epstein-Barr virus, cytomegalovirus, and varicella zoster virus polymerase chain reaction studies were negative and there was no evidence of hematological malignancy. Bone marrow biopsy demonstrated hypocellularity and trilineage hypoplasia with corresponding aspirate flow cytometry confirming the absence of acute leukemia. The patient was started on subcutaneous granulocyte-colony stimulating factor, provided transfusion support with packed red blood cells and platelets. Despite these measures, his blood count failed to recover, and he was discharged on eltrombopag 150 mg daily with plans for outpatient transfusion support. DPA was permanently discontinued, and he was prescribed trientine 750 mg daily. Unfortunately, his myelotoxicity remained consistent, requiring regular transfusions. He is currently undergoing evaluation for bone marrow transplant. Conclusion: DPA-induced myelotoxicity is a rare clinical entity. Our case demonstrates a unique clinical presentation of this phenomenon. Guidelines to mitigate the risk of and treat this toxicity remain to be determined.

Wilson Disease: Novel Diagnostic and Therapeutic Approaches

The Wilson disease (WD) research field is rapidly evolving, and new diagnostic and therapeutical approaches are expected to be change-gamers in the disease for the incoming years, after decades of slow changing options. Non-ceruloplasmin-bound copper assays for circulating bioavailable copper are being tested for use in monitoring therapy and may also help in the diagnosis of new cases of WD. Other diagnostic advances include the use of quantitative detection of ATP7B peptides in dried blood spots, a method that is being tested for use in the newborn screening for WD, and the use of metallothionein immunostaining of liver biopsy specimens to differentiate WD from other liver diseases. Ongoing and future trials of gene therapy and use of methanobactin are expected to restore biliary copper excretion from the liver, thus making a cure for WD a plausible therapeutic objective. With the aim of helping updating physicians, this review summarizes the novel methods for WD diagnosis and future therapies. Advancing understanding of the scientific advances that can be applied to WD will be critical for ensuring that our patients will receive the best current and future care.

Unusual presentation of Wilson's disease as proximal renal tubular acidosis with isolated phosphaturia

An adolescent girl presented with recurrent lower limb fractures and was managed as osteogenesis imperfecta. Low phosphate levels noted on routine investigation were the clue for the phosphaturia and subsequent diagnosis of proximal renal tubular acidosis (RTA). Further, with a history of jaundice, she was diagnosed with Wilson's disease, which was the underlying cause of proximal RTA with isolated phosphaturia and consequent fractures. Standard treatment for Wilson's disease along with supplementation of oral phosphate and bicarbonate led to complete recovery of fragile bones.

Efficacy and safety of D-penicillamine, trientine, and zinc in pediatric Wilson disease patients

OBJECTIVES

Wilson disease (WD) is a rare genetic disease affecting copper metabolism and the biliary tract's copper excretion. Lifelong medication is necessary to prevent liver failure, neurological complications, and death. Although D-penicillamine (DPA), trientine, and zinc are used to treat WD, there is limited research on the long-term outcomes of these drugs, especially in children. This study aimed to evaluate the efficacy and safety of DPA, trientine, and zinc in patients diagnosed with WD during childhood.

METHODS

Ninety out of 92 patients were included in the analysis, excluding two patients who underwent liver transplantation without drug treatment due to an acute liver failure diagnosis. Treatment outcomes and reasons for discontinuation of therapy in 148 treatment blocks (37 DPA, 50 trientine, and 61 zinc) were analyzed using Kaplan-Meier analysis.

RESULTS

The median age at diagnosis was 8.3 years. There was a statistically significant difference in drug changes due to treatment ineffectiveness among the three drugs: trientine (22/50, 44%), zinc (15/61, 25%), and DPA (2/37, 5%) (all p < 0.05). Regarding drug changes due to adverse effects, the rate was the highest for DPA, followed by zinc and trientine. There were significant differences between DPA and zinc, zinc and trientine (all p < 0.05), but no significant difference was observed between DPA and zinc (p = 0.22).

CONCLUSIONS

In pediatric WD, DPA, zinc, and trientine have therapeutic effects in that order. However, DPA and zinc are associated with more adverse effects compared to trientine.

The physiological and pathophysiological roles of copper in the nervous system

Copper is a critical trace element in biological systems due the vast number of essential enzymes that require the metal as a cofactor, including cytochrome c oxidase, superoxide dismutase and dopamine-β-hydroxylase. Due its key role in oxidative metabolism, antioxidant defence and neurotransmitter synthesis, copper is particularly important for neuronal development and proper neuronal function. Moreover, increasing evidence suggests that copper also serves important functions in synaptic and network activity, the regulation of circadian rhythms, and arousal. However, it is important to note that because of copper's ability to redox cycle and generate reactive species, cellular levels of the metal must be tightly regulated to meet cellular needs while avoiding copper-induced oxidative stress. Therefore, it is essential that the intricate system of copper transporters, exporters, copper chaperones and copper trafficking proteins function properly and in coordinate fashion. Indeed, disorders of copper metabolism such as Menkes disease and Wilson disease, as well as diseases linked to dysfunction of copper-requiring enzymes, such as SOD1-linked amyotrophic lateral sclerosis, demonstrate the dramatic neurological consequences of altered copper homeostasis. In this review, we explore the physiological importance of copper in the nervous system as well as pathologies related to improper copper handling.

Effects of trientine and penicillamine on intestinal copper uptake: A mechanistic 64 Cu PET/CT study in healthy humans

BACKGROUND AND AIMS

Trientine (TRI) and D-penicillamine (PEN) are used to treat copper overload in Wilson disease. Their main mode of action is thought to be through the facilitation of urinary copper excretion. In a recent study, TRI was noninferior to PEN despite lower 24-hour urinary copper excretion than PEN. We tested whether TRI and/or PEN also inhibit intestinal copper absorption.

APPROACH AND RESULTS

Sixteen healthy volunteers were examined with positron emission tomography (PET)/CT 1 and 15 hours after an oral Copper-64 ( 64 Cu) dose. They then received 7 days of either PEN or TRI (trientine tetrahydrochloride), after which the 64 Cu PET/CT scans were repeated. Venous blood samples were also collected. Pretreatment to posttreatment changes of the hepatic 64 Cu uptake reflect the effect of drugs on intestinal absorption. 64 Cu activity was normalized to dose and body weight and expressed as the mean standard uptake value. TRI (n=8) reduced hepatic 64 Cu activity 1 hour after 64 Cu dose from 6.17 (4.73) to 1.47 (2.97) standard uptake value, p <0.02, and after 15 hours from 14.24 (3.09) to 6.19 (3.43), p <0.02, indicating strong inhibition of intestinal 64 Cu absorption. PEN (n=8) slightly reduced hepatic standard uptake value at 15 hours, from 16.30 (5.63) to 12.17 (1.44), p <0.04.

CONCLUSIONS

In this mechanistic study, we show that TRI inhibits intestinal copper absorption, in addition to its cupriuretic effect. In contrast, PEN has modest effects on the intestinal copper absorption. This may explain why TRI and PEN are equally effective although urinary copper excretion is lower with TRI. The study questions whether the same therapeutic targets for 24-hour urinary excretion apply to both drugs.

Wilson Disease: Copper-Mediated Cuproptosis, Iron-Related Ferroptosis, and Clinical Highlights, with Comprehensive and Critical Analysis Update

Wilson disease is a genetic disorder of the liver characterized by excess accumulation of copper, which is found ubiquitously on earth and normally enters the human body in small amounts via the food chain. Many interesting disease details were published on the mechanistic steps, such as the generation of reactive oxygen species (ROS) and cuproptosis causing a copper dependent cell death. In the liver of patients with Wilson disease, also, increased iron deposits were found that may lead to iron-related ferroptosis responsible for phospholipid peroxidation within membranes of subcellular organelles. All topics are covered in this review article, in addition to the diagnostic and therapeutic issues of Wilson disease. Excess Cu2+ primarily leads to the generation of reactive oxygen species (ROS), as evidenced by early experimental studies exemplified with the detection of hydroxyl radical formation using the electron spin resonance (ESR) spin-trapping method. The generation of ROS products follows the principles of the Haber-Weiss reaction and the subsequent Fenton reaction leading to copper-related cuproptosis, and is thereby closely connected with ROS. Copper accumulation in the liver is due to impaired biliary excretion of copper caused by the inheritable malfunctioning or missing ATP7B protein. As a result, disturbed cellular homeostasis of copper prevails within the liver. Released from the liver cells due to limited storage capacity, the toxic copper enters the circulation and arrives at other organs, causing local accumulation and cell injury. This explains why copper injures not only the liver, but also the brain, kidneys, eyes, heart, muscles, and bones, explaining the multifaceted clinical features of Wilson disease. Among these are depression, psychosis, dysarthria, ataxia, writing problems, dysphagia, renal tubular dysfunction, Kayser-Fleischer corneal rings, cardiomyopathy, cardiac arrhythmias, rhabdomyolysis, osteoporosis, osteomalacia, arthritis, and arthralgia. In addition, Coombs-negative hemolytic anemia is a key feature of Wilson disease with undetectable serum haptoglobin. The modified Leipzig Scoring System helps diagnose Wilson disease. Patients with Wilson disease are well-treated first-line with copper chelators like D-penicillamine that facilitate the removal of circulating copper bound to albumin and increase in urinary copper excretion. Early chelation therapy improves prognosis. Liver transplantation is an option viewed as ultima ratio in end-stage liver disease with untreatable complications or acute liver failure. Liver transplantation finally may thus be a life-saving approach and curative treatment of the disease by replacing the hepatic gene mutation. In conclusion, Wilson disease is a multifaceted genetic disease representing a molecular and clinical challenge.

Constructing "smart" chelators by using an activatable prochelator strategy for the treatment of Wilson's disease

Wilson's disease (WD) is a genetic disorder that primarily leads to the pathological accumulation of copper (Cu) in the liver, causing an abnormal increase in reactive oxygen species (ROS). The prevailing clinical therapy for WD involves lifelong use of Cu chelation drugs to facilitate Cu excretion in patients. However, most available drugs exert severely side-effects due to their non-specific excretion of Cu, unsuitable for long-term use. In this study, we construct a prochelator that enables precise and controlled delivery of Cu chelator drugs to the liver in WD model, circumventing toxic side effects on other organs and normal tissues. This innovative prochelator rapidly releases the chelator and the fluorescent molecule methylene blue (MB) upon activation by ROS highly expressed in the liver of WD. The released chelator coordinates with Cu, efficiently aiding in Cu removal from the body and effectively inhibiting the pathological progression of WD.

Prevalence, Incidence, and Treatment Pattern of Wilson's Disease Using National Health Insurance Data From 2010-2020, Korea

BACKGROUND

Wilson's disease (WD) is an autosomal recessive disorder in which copper (Cu) accumulates in organs, particularly in the liver and central nervous system. This study aimed to investigate the prevalence, incidence, and treatment patterns of WD patients in Korea.

METHODS

National Health Insurance System (NHIS) claims data from 2010 to 2020 were analyzed. patients with WD as a primary or additional diagnosis at least once were identified using the International Classification of Diseases (ICD)-10 disease code E83.0 and a record for a registration program for rare intractable diseases in Korea.

RESULTS

The average age- and sex-adjusted prevalence and incidence of WD between 2010 and 2020 were 3.06/100,000 and 0.11/100,000, respectively. The mean age of the patients with newly diagnosed WD was 21.0 ± 15.9 years. Among the 622 WD incident cases during the study period, 19.3% of the patients had liver cirrhosis and 9.2% had received liver transplantation. Psychological and neurological diseases were present in 40.7% and 48.1% of the patients, respectively. Regarding the diagnosis of WD, liver biopsy was performed in only 51.6% of new cases. D-penicillamine, trientine, or zinc were prescribed in 81.5% of the incident cases, and the treatment uptake rates decreased with increasing age.

CONCLUSION

The prevalence of WD in Korea is 3.06/100,000 and approximately 1,800 patients use medical services annually. A significant proportion of patients are diagnosed at the cirrhotic stage and not treated with Cu-chelating therapeutics, suggesting the need for early diagnosis and adequate treatment to improve prognosis.

Copper in Gynecological Diseases

Copper (Cu) is an essential micronutrient for the correct development of eukaryotic organisms. This metal plays a key role in many cellular and physiological activities, including enzymatic activity, oxygen transport, and cell signaling. Although the redox activity of Cu is crucial for enzymatic reactions, this property also makes it potentially toxic when found at high levels. Due to this dual action of Cu, highly regulated mechanisms are necessary to prevent both the deficiency and the accumulation of this metal since its dyshomeostasis may favor the development of multiple diseases, such as Menkes' and Wilson's diseases, neurodegenerative diseases, diabetes mellitus, and cancer. As the relationship between Cu and cancer has been the most studied, we analyze how this metal can affect three fundamental processes for tumor progression: cell proliferation, angiogenesis, and metastasis. Gynecological diseases are characterized by high prevalence, morbidity, and mortality, depending on the case, and mainly include benign and malignant tumors. The cellular processes that promote their progression are affected by Cu, and the mechanisms that occur may be similar. We analyze the crosstalk between Cu deregulation and gynecological diseases, focusing on therapeutic strategies derived from this metal.

The Specific Copper(II) Chelator TDMQ20 Is Efficient for the Treatment of Wilson's Disease in Mice

(1) Background: In patients with Wilson's disease, the deficiency of the copper carrier ATP7B causes the accumulation of copper in the liver, brain and various other organs. Lifelong treatment is therefore mandatory, using copper chelators to increase the excretion of copper and to avoid life-threatening damage. The clinically used reference drug, D-penicillamine, exhibit numerous adverse effects, especially a frequent severe and irreversible neurological worsening, mainly due to its lack of metal selectivity; (2) Methods: A new tetradentate ligand based on an 8-aminoquinoline entity, named TDMQ20, which is highly selective for copper compared with other metal ions, is evaluated in "toxic milk" TX mice as an oral treatment of this Wilson's disease murine model; (3) Results: The concentration of copper in the liver of "toxic milk" TX mice decreased and the fecal excretion of copper increased upon oral treatment with TDMQ20. Both effects are dose-dependent, and more pronounced than those of D-penicillamine; (4) Conclusions: The TDMQ20 copper chelator is more efficient than the reference drug D-penicillamine for the treatment of a Wilson's disease murine model. Pharmacological data obtained with TDMQ20 on the TX mouse model strongly support the selection of this ligand as a drug candidate for this genetic disease.

Evolving approaches in glioma treatment: harnessing the potential of copper metabolism modulation

The key properties and high versatility of metal nanoparticles have shed new perspectives on cancer therapy, with copper nanoparticles gaining great interest because of the ability to couple the intrinsic properties of metal nanoparticles with the biological activities of copper ions in cancer cells. Copper, indeed, is a cofactor involved in different metabolic pathways of many physiological and pathological processes. Literature data report on the use of copper in preclinical protocols for cancer treatment based on chemo-, photothermal-, or copper chelating-therapies. Copper nanoparticles exhibit anticancer activity via multiple routes, mainly involving the targeting of mitochondria, the modulation of oxidative stress, the induction of apoptosis and autophagy, and the modulation of immune response. Moreover, compared to other metal nanoparticles (e.g. gold, silver, palladium, and platinum), copper nanoparticles are rapidly cleared from organs with low systemic toxicity and benefit from the copper's low cost and wide availability. Within this review, we aim to explore the impact of copper in cancer research, focusing on glioma, the most common primary brain tumour. Glioma accounts for about 80% of all malignant brain tumours and shows a poor prognosis with the five-year survival rate being less than 5%. After introducing the glioma pathogenesis and the limitation of current therapeutic strategies, we will discuss the potential impact of copper therapy and present the key results of the most relevant literature to establish a reliable foundation for future development of copper-based approaches.

Challenges and dilemmas in pediatric hepatic Wilson's disease

Wilson disease is an autosomal recessive disorder affecting the ATP7B gene located on chromosome 13q. This leads to copper deposition in various organs, most importantly in the liver and brain. The genetic mutations are vast, well reported in the West but poorly documented in developing countries. Hence the diagnosis is made with a constellation of clinico-laboratory parameters which have significant overlap with other liver diseases and often pose a significant dilemma for clinicians. Diagnostic scoring systems are not fool-proof. The availability and affordability of chelators in developing countries impact the drug compliance of patients. While D-penicillamine is a potent drug, its side effects lead to drug discontinuation. Trientine is cost-prohibitive in developing countries. There is no single test to assess the adequacy of chelation. Exchangeable urinary copper is an essential upcoming diagnostic and prognostic tool. In the presence of cirrhosis, hypersplenism clouds the assessment of myelosuppression of drugs. Similarly, it may be difficult to distinguish disease tubulopathy from drug-induced glomerulonephritis. Neurological worsening due to chelators may appear similar to disease progression. Presentation as fulminant hepatic failure requires rapid workup. There is a limited window of opportunity to salvage these patients with the help of plasmapheresis and other liver-assisted devices. This review addresses the challenges and clinical dilemmas faced at beside in developing countries.

Significant heterogeneity in the diagnosis and long-term management of Wilson disease: Results from a large multicenter Spanish study

There is uncertainty regarding Wilson's disease (WD) management.

OBJECTIVES

To assess, in a multicenter Spanish retrospective cohort study, whether the approach to WD is homogeneous among centers.

METHODS

Data on WD patients followed at 32 Spanish hospitals were collected.

RESULTS

153 cases, 58% men, 20.6 years at diagnosis, 69.1% hepatic presentation, were followed for 15.5 years. Discordant results in non-invasive laboratory parameters were present in 39.8%. Intrahepatic copper concentration was pathologic in 82.4%. Genetic testing was only done in 56.6% with positive results in 83.9%. A definite WD diagnosis (Leipzig score ≥4) was retrospectively confirmed in 92.5% of cases. Chelating agents were standard initial therapy (75.2%) with frequent modifications (57%), particularly to maintenance zinc. Enzyme normalization was not achieved by one third, most commonly in the setting of poor compliance, lack of genetic mutations and/or presence of cardiometabolic risk factors. Although not statistically significant, there were trends for sex differences in number of diagnosed cases, age at diagnosis and biochemical response.

CONCLUSIONS

Significant heterogeneity in diagnosis and management of WD patients emerges from this multicenter study that includes both small and large reference centers. The incorporation of genetic testing will likely improve diagnosis. Sex differences need to be further explored.

Wilson's Disease: A Prevalence Study in a Portuguese Population

Introduction Wilson's disease (WD) is a rare and underdiagnosed genetic disorder caused by anomalous tissue copper deposition, and for which epidemiological studies, specifically in Portugal, are scarce. Objectives This study aimed to evaluate the prevalence and incidence of WD and provide a description of its main clinical and laboratory features. Methods A retrospective study was carried out, with a search between 1995 and 2015, of all patients with a minimum follow-up of three months and birth confirmed in the northern region of Portugal, with an estimated population of 3,689,682 inhabitants. Database collection was based on the Portuguese National Health Service's clinical coding system, relying on clinical data from 13 northern Portuguese hospitals, liver biopsy histology results, and hospital prescription records. Clinical and biochemical correlations were statistically assessed using chi-square, Mann-Whitney U, Friedman, and Wilcoxon tests. Results Over the 20-year period, a prevalence of 1:37.000 and an incidence of one per million person-year was found. A total of 94 patients were analyzed, with a slight male predominance (53%), the majority with the onset of clinical manifestations in pediatric age (56%), with a median age at diagnosis of 16.6 years (interquartile range of 12.3-20,.8 years). Most patients presented with predominant liver disease (54.8%), with more than a third with cirrhosis; mixed hepatic and neurological manifestations in 17.9%; and mainly neurological symptoms in 10.7% of the patients. Neurological impairment was strongly associated with delayed development of the manifestations of the disease (p = 0.001) and also a higher detection of Kayser-Fleischer rings (p < 0.001), present in 27.0% of the patients. Regarding therapy, penicillamine has been the most widely used, with adverse reactions reported in 24.8%. At six and 12 months after initiation of therapy, a significant decrease in liver enzymes was found (ALT: p = 0.002; AST: p = 0.002, respectively), but no significant reduction was observed in urinary copper excretion. Conclusion This was one of the first studies regarding WD prevalence in a Portuguese population, contributing to a better understanding of the epidemiology, diagnosis, and management of WD in the northern region of Portugal. WD should be considered in any individual with unexplained hepatic or neurological manifestations, and initial symptoms may manifest at an early age, even in children less than five years old. A high percentage of patients were identified in the early stages of the disease by asymptomatic elevation of transaminases. Following copper chelation therapy, cytolysis markers appear to be more sensitive indicators of treatment response.

Evaluation of vitamin B6 supplementation in Wilson's disease patients treated with D-penicillamine

INTRODUCTION

Wilson's disease (WD) is a copper metabolism disorder characterised by a progressive accumulation of this metal mainly in the liver and the brain. Treatment is based on the removal of copper operated by the chelators, among which, D-penicillamine (DP) is prescribed as a first-line treatment in most situations. There is some evidence in linking the use of DP with a risk of vitamin B6; therefore, vitamin supplementation is sometimes recommended, although non-consensually. The objective of our study was to evaluate the level of vitamin B6 in WD patients treated with DP with and without associated supplementation.

METHODOLOGY

All WD patients followed at the National Reference Centre for WD in Lyon between January 2019 and December 2020 treated with DP for more than 1 year were included and separated in two groups according to vitamin B6 supplementation. The level of vitamin B6 was measured by the determination of pyridoxal phosphate (PLP).

RESULTS

A total of 37 patients were included. Average age of 23.3±14.8 years, 15 patients with <18 years. Median duration of treatment was 51 (55.8) months. 15 patients were under vitamin B6 supplementation and 22 had interrupted it for more than 1 year. The median PLP level was significantly higher in the group with supplementation, 137.2 (86.7) nmol/L vs 64.9 (30.8) nmol/(p<0.01). No patient had a PLP level<35 nmol/L.

CONCLUSION

Long-term stable WD patients under DP treatment probably do not need vitamin B6 supplementation.

Experimental pharmacology: Targeting metabolic pathways

Since the discovery of the treatment for Wilson disease a growing number of treatable inherited dystonias have been identified and their search and treatment have progressively been implemented in the clinics of patients with dystonia. While waiting for gene therapy to be more widely and adequately translated into the clinical setting, the efforts to divert the natural course of dystonia reside in unveiling its pathogenesis. Specific metabolic treatments can rewrite the natural history of the disease by preventing neurotoxic metabolite accumulation or interfering with the cell accumulation of damaging metabolites, restoring energetic cell fuel, supplementing defective metabolites, and supplementing the defective enzyme. A metabolic derangement of cell homeostasis is part of the progression of many non-metabolic genetic lesions and could be the target for possible metabolic approaches. In this chapter, we provided an update on treatment strategies for treatable inherited dystonias and an overview of genetic dystonias with new experimental therapeutic approaches available or close to clinical translation.

Stimulation of Liver Fibrosis by N2 Neutrophils in Wilson's Disease

BACKGROUND & AIMS

Wilson's disease is an inherited hepatoneurologic disorder caused by mutations in the copper transporter ATP7B. Liver disease from Wilson's disease is one leading cause of cirrhosis in adolescents. Current copper chelators and zinc salt treatments improve hepatic presentations but frequently worsen neurologic symptoms. In this study, we showed the function and machinery of neutrophil heterogeneity using a zebrafish/murine/cellular model of Wilson's disease.

METHODS

We investigated the neutrophil response in atp7b-/- zebrafish by live imaging, movement tracking, and transcriptional analysis in sorted cells. Experiments were conducted to validate liver neutrophil heterogeneity in Atp7b-/- mice. In vitro experiments were performed in ATP7B-knockout human hepatocellular carcinomas G2 cells and isolated bone marrow neutrophils to reveal the mechanism of neutrophil heterogeneity.

RESULTS

Recruitment of neutrophils into the liver is observed in atp7b-/- zebrafish. Pharmacologic stimulation of neutrophils aggravates liver and behavior defects in atp7b-/- zebrafish. Transcriptional analysis in sorted liver neutrophils from atp7b-/- zebrafish reveals a distinct transcriptional profile characteristic of N2 neutrophils. Furthermore, liver N2 neutrophils also were observed in ATP7B-knockout mice, and pharmacologically targeted transforming growth factor β1, DNA methyltransferase, or signal transducer and activator of transcription 3 reduces liver N2 neutrophils and improves liver function and alleviates liver inflammation and fibrosis in ATP7B-knockout mice. Epigenetic silencing of Socs3 expression by transforming growth factor β1 contributes to N2-neutrophil polarization in isolated bone marrow neutrophils.

CONCLUSIONS

Our findings provide a novel prospect that pharmacologic modulation of N2-neutrophil activity should be explored as an alternative therapeutic to improve liver function in Wilson's disease.

Challenges in pediatric inherited/metabolic liver disease: Focus on the disease spectrum, diagnosis and management of relatively common disorders

The clinical scenario of pediatric liver disease is becoming more intricate due to changes in the disease spectrum, in which an increasing number of inherited/ metabolic liver diseases are reported, while infectious diseases show a decreasing trend. The similar clinical manifestations caused by inherited/metabolic diseases might be under-recognized or misdiagnosed due to nonspecific characteristics. A delayed visit to a doctor due to a lack of symptoms or mild symptoms at an early stage will result in late diagnosis and treatment. Moreover, limited diagnostic approaches, especially liver biopsy, are not easily accepted by pediatric patients, leading to challenges in etiological diagnosis. Liver dysfunction due to inherited/metabolic diseases is often caused by a variety of metabolites, so precision treatment is difficult; symptomatic treatment is a compelling option for inherited disorders.

Long-term outcome of patients with neurological form of Wilson's disease compliant to the de-coppering treatment

BACKGROUND

A substantial proportion of Wilson's disease (WD) patients exhibit residual neurological symptoms. Data on the prognostic value of initial clinical features and treatment choices in WD patients compliant to the therapy is relatively sparse.

AIM

The aim of the present study was to identify predictors of the long-term outcome of patients with WD with good treatment adherence.

METHODS

Forty patients with neurological form of WD were evaluated before the de-coppering treatment initiation (based on the medical records) and after mean 15.25 ± 11.24 years of the stable treatment. Severity of neurological symptoms were assessed with a tier two of Global Assessment Scale (GAS) for Wilson's Disease.

RESULTS

The most frequent symptoms prior to treatment initiation were dysarthria (90%), tremor (90%), clumsiness (67.5%), depression (67.5%), and gait disturbance (62.5%). Significant decrease in the frequency of dysarthria, clumsiness, tremor, gait disturbance, postural instability and an improvement in school/work performance were observed after the long-term treatment, while frequency of dysphagia, drooling, bradykinesia and rigidity, dystonic and choreatic features did not change. Overall symptom severity decreased over time. Presence of dystonia before treatment initiation was the only identified predictor of worse residual GAS score. Greater severity of residual dystonia was associated with female gender and longer disease duration.

CONCLUSION

Although patients with neurological form of WD compliant to de-coppering treatment had favorable disease outcome, a significant burden of residual neurological symptoms was observed after the long-term follow-up. Dystonia at disease onset was the only identified predictor of the worse long-term outcome.

[Wilson's disease: overview]

Wilson's disease (WD) is an uncommon hereditary disorder caused by a deficiency in the ATP7B transporter. The protein codified by this gene facilitates the incorporation of the copper into ceruloplasmin. Therefore, WD accumulates copper primary in the liver and secondary in other organs, such as the central nervous system. It represents a wide spectrum of disease, ranging from being asymptomatic in some patients to promote an acute liver failure in others. The diagnosis requires a combination of clinical signs and symptoms, as well as some diagnostic tests such as the measurement of serum ceruloplasmin, the urinary excretion of copper, the liver biopsy or the genetic testing. The treatment must be maintained lifelong and includes some drugs such as chelating agents (penicillamine and trientine) and inhibitors of the copper absorption (zinc salts). Lastly, the liver transplant should be an option for patients with end-stage liver disease.

Prevalence and Significance of Autoantibody Seropositivity in Children with Wilson's Disease

Autoantibodies occur in healthy subjects as well as in children with Wilson's disease (WD), but their prevalence and significance are unknown. Thus, we aimed to assess the prevalence of autoantibodies and autoimmune markers, and their relationship to liver injury in WD children. The study included 74 WD and 75 healthy children as a control group. Patients with WD underwent transient elastography (TE) examinations, as well as determination of liver function tests, copper metabolism markers, and serum immunoglobulins (Ig). In the sera of the WD patients and controls, anti-nuclear (ANA), anti-smooth muscle, anti-mitochondrial, anti-parietal cell, anti-liver/kidney microsomal, anti-neutrophil cytoplasmic autoantibodies, and specific celiac antibodies were determined. Among the autoantibodies, only the prevalence of ANA in children with WD was higher than in the controls. There was no significant relationship between the presence of autoantibodies and liver steatosis or stiffness after TE. However, advanced liver stiffness (E > 8.2 kPa) was related to IgA, IgG, and gamma globulin production. The type of treatment did not influence the prevalence of autoantibodies. Our results suggest that autoimmune disturbances in WD might not be directly related to liver damage as expressed by steatosis and/or liver stiffness after TE.

Experience on switching trientine formulations in Wilson disease: Efficacy and safety after initiation of TETA 4HCl as substitute for TETA 2HCl

BACKGROUND AND AIM

This retrospective, multicenter study aims to assess the efficacy and safety in Wilson disease (WD) patients treated with trientine tetrahydrochloride (TETA 4HCl) after switch from trientine dihydrochloride (TETA 2HCl).

METHODS

In total, 68 WD patients with stable copper metabolism were identified to receive TETA 4HCl (Cuprior™) after previous treatment with TETA 2HCl. We analyzed biochemical markers such as urinary copper, serum copper, non-coeruloplasmin bound copper (NCC), and transaminases as well as clinical scores (APRI; FIB-4 score) at baseline with a follow-up (FU) of 12 months. Safety of TETA 4HCl treatment was based on reported adverse events (AEs).

RESULTS

The study cohort reflects a common WD cohort with a mean age of 20.3 years at diagnosis and 38.3 years at baseline. There are no significant differences concerning serum copper, NCC, transaminases, APRI, and FIB-4 score in the 3-month FU. Six-month FU revealed a decreased AST (P = 0.008), APRI (P = 0.042), and FIB-4 score (P = 0.039). GGT varied only borderline significantly in the 3-month, but not in the 6-month FU. Comparison of urinary copper within the subsets did not reveal a difference to baseline in all FUs, suggesting stable control of copper metabolism. Few AEs during TETA 4HCl treatment were reported, most commonly gastrointestinal discomfort. Only three treatments with TETA 4HCl were discontinued.

CONCLUSION

Copper parameters and liver function were stable after treatment switch to TETA 4HCl. Treatment with TETA 4HCl was generally well tolerated. This study indicates that the switch from TETA 2HCl to TETA 4HCl is safe and viable.

Trientine tetrahydrochloride versus penicillamine for maintenance therapy in Wilson disease (CHELATE): a randomised, open-label, non-inferiority, phase 3 trial

BACKGROUND

Wilson disease is an inherited disorder of copper transport. Whereas penicillamine is used therapeutically to re-establish copper balance, trientine is indicated for patients with penicillamine intolerance. We aimed to compare penicillamine with trientine tetrahydrochloride (TETA4) for maintenance therapy in patients with Wilson disease.

METHODS

We conducted a randomised, open-label, non-inferiority, phase 3 trial at 15 health-care centres across nine countries (patients were recruited from 13 of these health-care centres across Brazil, Europe, and the USA). We enrolled patients aged 18-75 years with stable Wilson disease who were treated for at least 1 year with penicillamine. Patients entered a 12-week period to determine stability through clinical assessment by site investigators and predefined thresholds for serum non-caeruloplasmin-bound copper (NCC; by an exchangeable copper assay; 25-150 μg/L), 24 h urinary copper excretion (100-900 μg/24 h), and alanine aminotransferase (ALT; <2 × upper limit of normal). Stable patients were randomly assigned (1:1) to continue receiving the maintenance twice daily dose of oral penicillamine or switched mg-for-mg to oral TETA4 centrally with a web-based system using minimisation. The primary endpoint, assessed 24 weeks after randomisation, was NCC by speciation assay. The non-inferiority margin of mean difference in NCC by speciation assay was -50 μg/L, as estimated by a general linear model for repeated visits, adjusted for baseline values. Further data on safety and efficacy were collected during a 24-week extension period. Data were analysed using an intention-to-treat approach. Safety was assessed in all patients who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT03539952 (active, not recruiting).

FINDINGS

Between June 4, 2018, and March 10, 2020, 77 patients were screened. 53 patients were randomly assigned (27 to the penicillamine group and 26 to the TETA4 group). After 24 weeks, the mean difference in serum NCC by speciation assay between the penicillamine group and TETA4 group was -9·1 μg/L (95% CI -24·2 to 6·1), with the lower limit of the 95% CI within the defined non-inferiority margin. At 24 weeks, urinary copper excretion was lower with TETA4 than with penicillamine (mean difference 237·5 μg/24 h (99% CI 115·6 to 359·4). At 48 weeks, TETA4 remained non-inferior to penicillamine in terms of NCC by speciation assay (mean difference NCC -15·5 μg/L [95% CI -34·5 to 3·6]). Urinary copper excretion at 48 weeks remained in the expected range for well treated patients in both study groups, and the mean difference (124·8 μg/24 h [99% CI -37·6 to 287·1]) was not significantly different. At 24 weeks and 48 weeks, masked clinical adjudication of stability assessed by three independent clinicians confirmed clinical stability (100%) of all participants, in agreement with the stability seen with the NCC by speciation assay. There were no notable changes in either the Clinical Global Impression of Change or Unified Wilson Disease Rating Scale (neurological assessment) from baseline (pre-randomisation) at weeks 24 and 48. The mean change in serum total copper from baseline to 24 weeks was 17·6 μg/L (99% CI -9·5 to 44·7) with penicillamine and -6·3 μg/L (-34·7 to 22·1) with TETA4, and the mean change in serum total caeruloplasmin from baseline to 24 weeks was 1·8 mg/L (-19·2 to 22·8) with penicillamine and -2·2 mg/L (-6·1 to 1·7) with TETA4. All liver enzymes were similar at 24 weeks and 48 weeks, with the exception of elevated ALT concentration at 48 weeks for patients in the TETA4 group. Penicillamine was associated with three post-randomisation serious adverse events (leukopenia, cholangiocarcinoma, and hepatocellular cancer); none were reported for TETA4. The most common treatment-emergent adverse events were headache for penicillamine (five [19%] of 27 patients vs two [8%] of 26) and abdominal pain for TETA4 (one [4%] vs four [15%]); all treatment-emergent adverse events resolved and were mild to moderate. One patient developed a rash with TETA4 that resolved on discontinuation of therapy.

INTERPRETATION

The efficacy of TETA4 as oral maintenance therapy was non-inferior to penicillamine and well tolerated in adults with Wilson disease.

FUNDING

Orphalan.

Copper homeostasis and cuproptosis in health and disease

As an essential micronutrient, copper is required for a wide range of physiological processes in virtually all cell types. Because the accumulation of intracellular copper can induce oxidative stress and perturbing cellular function, copper homeostasis is tightly regulated. Recent studies identified a novel copper-dependent form of cell death called cuproptosis, which is distinct from all other known pathways underlying cell death. Cuproptosis occurs via copper binding to lipoylated enzymes in the tricarboxylic acid (TCA) cycle, which leads to subsequent protein aggregation, proteotoxic stress, and ultimately cell death. Here, we summarize our current knowledge regarding copper metabolism, copper-related disease, the characteristics of cuproptosis, and the mechanisms that regulate cuproptosis. In addition, we discuss the implications of cuproptosis in the pathogenesis of various disease conditions, including Wilson's disease, neurodegenerative diseases, and cancer, and we discuss the therapeutic potential of targeting cuproptosis.

Chelation Combination-A Strategy to Mitigate the Neurotoxicity of Manganese, Iron, and Copper?

The chelating thiol dimercaptosuccinate (DMSA) and the traditional agent D-penicillamine (PSH) are effective in enhancing the urinary excretion of copper (Cu) and lead (Pb) in poisoned individuals. However, DMSA, PSH, EDTA (ethylenediamine tetraacetate), and deferoxamine (DFOA) are water-soluble agents with limited access to the central nervous system (CNS). Strategies for mobilization of metals such as manganese (Mn), iron (Fe), and Cu from brain deposits may require the combined use of two agents: one water-soluble agent to remove circulating metal into urine, in addition to an adjuvant shuttler to facilitate the brain-to-blood mobilization. The present review discusses the chemical basis of metal chelation and the ligand exchange of metal ions. To obtain increased excretion of Mn, Cu, and Fe, early experiences showed promising results for CaEDTA, PSH, and DFOA, respectively. Recent experiments have indicated that p-amino salicylate (PAS) plus CaEDTA may be a useful combination to remove Mn from binding sites in CNS, while the deferasirox-DFOA and the tetrathiomolybdate-DMSA combinations may be preferable to promote mobilization of Fe and Cu, respectively, from the CNS. Further research is requested to explore benefits of chelator combinations.

Multicentre, retrospective study to assess long-term outcomes of chelator based treatment with trientine in Wilson disease patients withdrawn from therapy with d -penicillamine

OBJECTIVES

Trientine dihydrochloride (TETA-2HCl) has been used for the treatment of Wilson disease for over 30 years. The current study was designed to systematically evaluate existing data to further define the long-term outcome of the efficacy and tolerability of TETA-2HCl in Wilson disease patients.

METHODS

Medical records of 77 Wilson disease patients were reviewed to collect data on hepatic and neurologic symptoms, copper (Cu) homeostasis and adverse events. Data were collected for 48 months after initiation of TETA-2HCl after withdrawal of D-penicillamine treatment.

RESULTS

Mean duration of TETA-2HCl treatment was 8 years (range 5 months-32.5 years). Over the course of TETA-2HCl treatment, 35% of patients had no hepatic symptoms whereas in 49.4% of patients, hepatic symptoms improved. They remained unchanged in 10.4% of patients and worsened in 5.2% of patients. No patients progressed to acute hepatic failure or necessity of a liver transplant. During TETA-2HCl treatment, 46.7% of patients had no neurologic symptoms; in 14.3% of patients, neurologic symptoms improved whereas in 36.4% of patients, they remained stable and worsened in 2.6% of patients. During the evaluation period, 12 patients discontinued TETA-2HCl treatment due to: anemia ( N = 1), inadequate hepatic response ( N = 2), switch to zinc treatment ( N = 8) and patient's decision to withdraw from treatment ( N = 1). Treatment-emergent adverse events were reported by 24.7% of the patients of which gastrointestinal disorders (9.1%) and nervous system disorders (5.2%) were most reported.

CONCLUSIONS

TETA-2HCl is well-tolerated and effective in Wilson disease patients following the withdrawal of treatment with D-penicillamine. ClinicalTrials.govIdentifier : NCT02426905.

D-Penicillamine Reveals the Amelioration of Seizure-Induced Neuronal Injury via Inhibiting Aqp11-Dependent Ferroptosis

Repetitive seizures, a common phenomenon in diverse neurologic conditions such as epilepsy, can undoubtedly cause neuronal injury and our prior work reveals that ferroptosis is a contributing factor of neuronal damage post seizure. However, there is no drug available in clinical practice for ameliorating seizure-induced neuronal impairment via targeting ferroptosis. Our present work aimed to explore whether D-penicillamine (DPA), an originally approved drug for treating Wilson's disease, inhibited neuronal ferroptosis and alleviated seizure-associated brain damage. Our findings revealed that DPA remarkably improved neuronal survival in kainic acid (KA)-treated mouse model. Furthermore, ferroptosis-associated indices including acyl-coA synthetase long chain family member 4 (ACSL4), prostaglandin-endoperoxide synthase 2 (Ptgs2) gene and lipid peroxide (LPO) level were significantly decreased in KA mouse model after DPA treatment. In a ferroptotic cell death model induced by glutamate or erastin, DPA was also validated to evidently suppress neuronal ferroptosis. The results from RNA-seq analysis indicated that Aqp11, a gene coding previously reported channel protein responsible for transporting water and small solutes, was identified as a molecular target by which DPA exerted anti-ferroptotic potential in neurons. The experimental results from in vivo Aqp11 siRNA transfer into the brain also confirmed that knockdown of Aqp11 abrogated the inhibitory effect of seizure-induced ferroptosis after DPA treatment, suggesting that the effects of DPA on ferroptosis process are dependent upon Aqp11. In conclusion, DPA can be repurposed to cure seizure disorders such as epilepsy.

The Role of Zinc in the Treatment of Wilson’s Disease

Wilson’s disease (WD) is a hereditary disorder of copper metabolism, producing abnormally high levels of non-ceruloplasmin-bound copper, the determinant of the pathogenic process causing brain and hepatic damage and dysfunction. Although the disease is invariably fatal without medication, it is treatable and many of its adverse effects are reversible. Diagnosis is difficult due to the large range and severity of symptoms. A high index of suspicion is required as patients may have only a few of the many possible biomarkers. The genetic prevalence of ATP7B variants indicates higher rates in the population than are currently diagnosed. Treatments have evolved from chelators that reduce stored copper to zinc, which reduces the toxic levels of circulating non-ceruloplasmin-bound copper. Zinc induces intestinal metallothionein, which blocks copper absorption and increases excretion in the stools, resulting in an improvement in symptoms. Two meta-analyses and several large retrospective studies indicate that zinc is equally effective as chelators for the treatment of WD, with the advantages of a very low level of toxicity and only the minor side effect of gastric disturbance. Zinc is recommended as a first-line treatment for neurological presentations and is gaining acceptance for hepatic presentations. It is universally recommended for lifelong maintenance therapy and for presymptomatic WD.

Wilson Disease in Children

The silver anniversary of the discovery of the Wilson disease gene ATP7B was a couple of years ago, and we continue to make progress both in our understanding of copper transportation using animal models as well as earlier diagnosis by availing of genetic testing. Wilson disease is multisystemic and the hepatic manifestations are seen more frequently in childhood, whereas neurologic manifestations are more common in adults; presentation may range from subtle changes to end-stage liver disease with or without encephalopathy as well as neuropsychiatric manifestations. Treatment remains with zinc and chelating agents such as D-penicillamine and trientine but newer agents and gene therapy are in clinical trials. Liver transplantation becomes necessary when medical therapy is not enough. Molecular diagnosis and genetic counseling is important.

Antifungal Effect of Penicillamine Due to the Selective Targeting of L-Homoserine O-Acetyltransferase

Due to the apparent similarity of fungal and mammalian metabolic pathways, the number of established antifungal targets is low, and the identification of novel ones is highly desirable. The results of our studies, presented in this work, indicate that the fungal biosynthetic pathway of L-methionine, an amino acid essential for humans, seems to be an attractive perspective. The MET2 gene from Candida albicans encoding L-homoserine O-acetyltransferase (CaMet2p), an enzyme catalyzing the first step in that pathway, was cloned and expressed as the native or the oligo-His-tagged fusion protein in Escherichia coli. The recombinant enzymes were purified and characterized for their basic molecular properties and substrate specificities. The purified MET2 gene product revealed the appropriate activity, catalyzed the conversion of L-homoserine (L-Hom) to O-acetyl-L-homoserine (OALH), and exhibited differential sensitivity to several L-Hom or OALH analogues, including penicillamine. Surprisingly, both penicillamine enantiomers (L- and D-Pen) displayed comparable inhibitory effects. The results of the docking of L- and D-Pen to the model of CaMet2p confirmed that both enantiomeric forms of the inhibitor are able to bind to the catalytic site of the enzyme with similar affinities and a similar binding mode. The sensitivity of some fungal cells to L-Pen, depending on the presence or absence of L-Met in the medium, clearly indicate Met2p targeting. Moreover, C. glabrata clinical strains that are resistant to fluconazole displayed a similar susceptibility to L-Pen as the wild-type strains. Our results prove the potential usefulness of Met2p as a molecular target for antifungal chemotherapy.

Efficacy and Safety of Two Salts of Trientine in the Treatment of Wilson’s Disease

Background: Wilson’s disease (WD) is one of the few genetic disorders that can be successfully treated with pharmacological agents. Copper-chelating agents (D-penicillamine and Trientine salts) and zinc salts have been demonstrated to be effective. There are two salts of trientine. Trientine dihydrochloride salt (TETA 2HCL) is unstable at room temperature and requires storage at 2–8 °C. Trientine tetrahydrochloride (TETA 4HCL) is a more stable salt of trientine that can be stored at room temperature. No comparative study between both of the salts of trientine has been performed to date. As the two chemical forms were available in France between 1970 and 2009, we conducted a study to evaluate their efficacy and safety profiles. Methods: This retrospective cohort study was conducted by reviewing data from the national WD registry in France. Forty-three WD patients who received TETA 2HCL or TETA 4HCL monotherapy for at least one year until 2010 were included. The primary endpoints were hepatic and neurological outcomes. Secondary endpoints were the events leading to a discontinuation of medication. Results: Changes in medication were common, leading to the analysis of 57 treatment sequences of TETA 4HCL or TETA 2HCL. The mean duration of treatment sequence was significantly longer in the TETA 4 HCL group (12.6 years) than in the TETA 2HCL group (7.6 years) (p = 0.011). Ten patients experienced both trientine salts: eight stopped TETA 4 HCL (six had a hepatologic phenotype and two had a neurological phenotype) because this treatment was not available anymore (mean duration 7.4 years). Three of these patients already experienced TETA 2 HCL before the sequence. Two patients with a hepatologic phenotype (one had a previous sequence of TETA 4 HCL before) stopped TETA 2 HCL because of cold storage issues (mean duration 42.8 years). The total number of sequences was 57. All of the patients were clinically stable. No difference in efficacy was detected. Both treatments were well tolerated, except for a case of recurrence of lupus erythematosus-like syndrome in the TETA 2HCL group. The major reason for interruption of TETA 4HCL was due to a discontinuation in production of this salt. The reasons for stopping TETA 2HCL were mainly due to adherence issues largely attributed to the cold storage requirement. Conclusions: The two salts of trientine were effective in treating patients with WD. However, interruption of TETA 2HCL was frequent, linked to the cold storage requirement. As adherence to treatment is a key factor in the successful management of WD, physicians need to be even more vigilant in detecting adherence difficulties in patients receiving treatment with TETA 2HCL.

Investigation and management of Wilson's disease: a practical guide from the British Association for the Study of the Liver

Wilson's disease is an autosomal-recessive disorder of copper metabolism with hepatic, neurological, psychiatric, ophthalmological, haematological, renal, and rheumatological manifestations. Making a diagnosis can be challenging given that no single test can confirm or exclude the disease, and diagnostic delays are common. Treatment protocols vary and adverse effects, including paradoxical neurological worsening, can occur. In this Review, we provide a practical guide to the diagnosis of Wilson's disease. We include recommendations on indications for testing, how to interpret results, and when additional investigations are required. We also cover treatment initiation, ideally under the guidance of a specialist centre for Wilson's disease, and the principles behind long-term management. This guidance was developed by a multidisciplinary group of Wilson's disease experts formed through the British Association for the Study of the Liver. The guidance has been endorsed by the British Society of Gastroenterology and approved by the Association of British Neurologists.

Practical insights into chronic management of hepatic Wilson’s disease

Wilson’s disease (WD) is a rare inherited disorder of human copper metabolism, with an estimated prevalence of 1:30000-1:50000 and a broad spectrum of hepatic and neuropsychiatric manifestations. In healthy individuals, the bile is the main route of elimination of copper. In WD patients, copper accumulates in the liver, it is released into the bloodstream, and is excreted in urine. Copper can also be accumulated in the brain, kidneys, heart, and osseous matter and causes damage due to direct toxicity or oxidative stress. Hepatic WD is commonly but not exclusively diagnosed in childhood or young adulthood. Adherent, non-cirrhotic WD patients seem to have a normal life expectancy. Nevertheless, chronic management of patients with Wilson’s disease is challenging, as available biochemical tests have many limitations and do not allow a clear identification of non-compliance, overtreatment, or treatment goals. To provide optimal care, clinicians should have a complete understanding of these limitations and counterbalance them with a thorough clinical assessment. The aim of this review is to provide clinicians with practical tools and suggestions which may answer doubts that can arise during chronic management of patients with hepatic WD. In particular, it summarises current knowledge on Wilson’s disease clinical and biochemical monitoring and treatment. It also analyses available evidence on pregnancy and the role of low-copper diet in WD. Future research should focus on trying to provide new copper metabolism tests which could help to guide treatment adjustments.

Clinical and Genetic Analysis in Neurological Wilson’s Disease Patients With Neurological Worsening Following Chelator Therapy

Objectives: None of the previous studies have focused on the genetic effect on neurological worsening in neurological Wilson’s disease (WD) patients following chelator therapy. We aimed to evaluate the clinical and genetic role in the occurrence of neurological worsening.

Methods: We retrospectively reviewed the medical records of neurological WD patients who received initial chelator therapy and genetic test. Clinical, laboratory, and genetic data were collected. The genotype was classified into two types: 1) severe mutation genotype: patients who carried at least one of the following three types of mutations: frameshift mutation, splicing mutation, or nonsense mutation; 2) non-severe mutation genotype: patients who only carried missense mutations. Then, the clinical features and genotype of the patients with and without neurological worsening were investigated.

Results: Forty-seven neurological WD patients were identified with a median age at onset of 16.17 years (range 7.75–47 years) and 35 (74.5%) males. The mean interval from onset to diagnosis was 0.6 years (range: 0.5 months-6.25 years). Neurological deterioration was observed in 29 patients (61.7%) and the other 18 patients (38.3%) were stable or improved during anti-copper treatment. The neurological worsening was completely irreversible in 6 cases (20.7%) and partially irreversible in 16 cases (55.2%). The common deteriorated symptoms were as follows: rigidity in 20 cases (69%), speech difficulties in 20 cases (69%)), walking difficulties in 13 cases (44.8%), dysphagia in 9 cases (31%), and salivation in 9 cases (31%). The patients with neurological worsening had significantly younger age (p = 0.028), shorter delayed diagnosis time (p = 0.011), higher rate of dystonia (p = 0.003), and severe mutation genotype (p = 0.036), compared to those without neurological worsening.

Conclusion: We found that younger age of onset, the presence of dystonia, and genotype with severe mutations may be predictive of neurological worsening in the neurological WD patients that received chelator therapy. For those patients, chelator therapy should be given with caution and needs closer observation during follow-up.

Adverse Events with D-penicillamine Therapy in Hepatic Wilson's Disease: A Single-Center Retrospective Audit

BACKGROUND AND OBJECTIVE: There are limited data on the adverse events of D-penicillamine in Wilson's disease (WD) that can result in dose modification or treatment discontinuation. The objective of this study was to observe the adverse events related to D-penicillamine in patients with hepatic WD.

METHODS

A retrospective audit of prospectively registered hepatic WD patients at a tertiary care center between December 2006 and January 2020 was carried out. Demographic variables, laboratory parameters, and details of treatment were noted. Adverse events (AEs) related to D-penicillamine treatment, the timing and management of these AEs were analysed.

RESULTS

The study included 112 patients with hepatic WD on D-penicillamine. D-penicillamine intolerance was seen in 28/112 (25%) over 179 person-years. Of the 28 AEs, severe AEs leading to permanent D-penicillamine discontinuation occurred in 16 (57%) [never reintroduced 12 (43%), discontinued after intolerant to rechallenge, 4 (14%)], temporary cessation followed by reintroduction to initial dose 13 (46%) and continuation with reduced dose in 3 (11%) patients. Overall, most common AEs were hematological [16, 57% (pancytopenia n = 8, bicytopenia n = 5 and hemolytic anemia n = 3)] while renal adverse events (n = 7, 25%) constituted the most common indication for permanent discontinuation. Cytopenias developed beyond 12 months of D-penicillamine initiation whereas hemolytic anemia developed within first 3 months. Following D-penicillamine discontinuation in 25 patients, it was reintroduced to initial dose in 13/25 (52%), switched to trientine due to neurological worsening in 2/25 (8%) and switched to zinc in 10/25 (40%). In patients with reintroduction, gradual dose escalation was tolerated in 9/13 (69%) with a recurrence of AEs leading to permanent discontinuation in 4/13 (31%).

CONCLUSION

D-penicillamine treatment is associated with significant AEs mainly related to blood, kidney, and skin. Temporary cessation of drug with reintroduction at a lower dose is an effective and safe option.

Designing Clinical Trials in Wilson's Disease

BACKGROUND AND AIMS

Wilson's disease (WD) is an autosomal-recessive disorder caused by ATP7B gene mutations leading to pathological accumulation of copper in the liver and brain. Adoption of initial treatments for WD was based on empirical observations. These therapies are effective, but there are still unmet needs for which treatment modalities are being developed. An increase of therapeutical trials is anticipated.

APPROACH AND RESULTS

The first Wilson Disease Aarhus Symposium (May 2019) included a workshop on randomized clinical trial design. The authors of the article were organizers or presented during this workshop, and this article presents their consensus on the design of clinical trials for WD, addressing trial population, treatment comparators, inclusion and exclusion criteria, and treatment endpoints. To achieve adequate recruitment of patients with this rare disorder, the study groups should include all clinical phenotypes and treatment-experienced as well as treatment-naïve patients.

CONCLUSIONS

The primary study endpoint should be clinical or a composite endpoint until appropriate surrogate endpoints are validated. Standardization of clinical trials will permit pooling of data and allow for better treatment comparisons, as well as reduce the future numbers of patients needed per trial.

Chelation therapy in liver diseases of childhood: Current status and response

Chelation is the mainstay of therapy in certain pediatric liver diseases. Copper and iron related disorders require chelation. Wilson’s disease (WD), one of the common causes of cirrhosis in children is treated primarily with copper chelating agents like D-penicillamine and trientine. D-Penicillamine though widely used due its high efficacy in hepatic WD is fraught with frequent adverse effects resulting discontinuation. Trientine, an alternative drug has comparable efficacy in hepatic WD but has lower frequency of adverse effects. The role of ammonium tetra-thiomolybdate is presently experimental in hepatic WD. Indian childhood cirrhosis is related to excessive copper ingestion, rarely seen in present era. D-Penicillamine is effective in the early part of this disease with reversal of clinical status. Iron chelators are commonly used in secondary hemochromatosis of liver in hemolytic anemias. There are strict chelation protocols during bone marrow transplant. The role of iron chelation in neonatal hemochromatosis is presently not in vogue due to its poor efficacy and availability of other modalities of therapy. Hereditary hemochromatosis is rare in children and the use of iron chelators in this condition is limited.