Evolving perspectives in Wilson disease: diagnosis, treatment and monitoring

Copper's dual role: Reviewing its impact on liver health and disease

As an essential trace element in the human body, Cu exists in the oxidation states of Cu(II) and Cu(I). The interconversion between these states is closely associated with various redox reactions and plays a pivotal role in cellular respiration regulation, energy metabolism, cell growth regulation, and angiogenesis promotion among other biological processes. As the primary metabolic organ, the liver synthesises and secretes Cu-binding proteins to maintain Cu homeostasis and regulate its metabolism. Studies have increasingly demonstrated that abnormally high or low levels of Cu can negatively affect the immune and metabolic microenvironment within the liver. In this review, we summarise the mechanisms underlying Cu metabolism and its dysregulation and highlight the potential involvement of disrupted Cu metabolism in several liver diseases. Our review provides insights that will help in the future development of novel therapeutic targets focusing on Cu metabolism.

A comparative analysis in monitoring 24-hour urinary copper in wilson disease: sampling on or off treatment?

BACKGROUND & AIM

Twenty-four-hour urinary copper excretion (24 h-UCE) is the standard diagnostic tool for dose adjustments in maintenance therapy in Wilson disease (WD) patients. Guidelines lack data if both variants of 24 h-UCE measurement (with or without 48 h of treatment interruption) are equally interpretable.

METHODS

Eighty-four patients with a confirmed diagnosis of WD treated with chelators (50% of patients with D-Penicillamine and 50% with trientine) and with pairwise 24-h-UCE values on-therapy and off-therapy were included in the analysis. Pairwise urinary sampling between October 2022 (T0) and a 12-month FU (T2) was compared, and exchangeable copper (CuEXC) was additionally measured at T0.

RESULTS

Among the 84 patients, 65% had predominant hepatic symptoms, the median age was 42 years, and 58% were female. At T0, patients were in the stable maintenance phase, with a median treatment duration of 21.9 years. The levels of the biochemical markers liver and copper metabolism remained stable over the 12-month observation period for all patients. 24 h-UCE off-therapy significantly decreased from T0 to T2 (p = 0.03), whereas no statistically significant differences were detected for 24 h-UCE after therapy. Both sampling methods did not correlate. CuEXC was significantly correlated with 24 h-UCE after 48 h of dose interruption (p = 0.018) but not with 24 h-UCE after therapy. A total of 46% of the 24 h-UCE value pairs were discordant, laying out the aimed therapeutic ranges given in current international guidelines.

CONCLUSION

Off-therapy 24 h-UCE reflects the "free" copper pool more accurately than does urinary sampling. The study shows discordant results for both sampling methods in approximately half of the patients, revealing that interpretation of 24 h-UCE with respect to chelator-dosing decisions should be performed with caution.

Heterologous Biosynthesis of Methanobactin from Methylocystis sp. Strain SB2 in Methylosinus trichosporium OB3b

Aerobic methanotrophs, or methane-consuming microbes, are strongly dependent on copper for their activity. To satisfy this requirement, some methanotrophs produce a copper-binding compound, or chalkophore, called methanobactin (MB). In addition to playing a critical role in methanotrophy, MB has also been shown to have great promise in treating copper-related human diseases, perhaps most significantly Wilson's disease. In this congenital disorder, copper builds up in the liver, leading to irreversible damage and, in severe cases, complete organ failure. Remarkably, MB has been shown to reverse such damage in animal models, and there is a great deal of interest in upscaling MB production for expanded clinical trials. Such efforts, however, are currently hampered as (1) the natural rate of MB production rate by methanotrophs is low, (2) the use of methane as a substrate for MB production is problematic as it is explosive in air, (3) there is limited understanding of the entire pathway of MB biosynthesis, and (4) the most attractive form of MB is produced by Methylocystis sp. strain SB2, a methanotroph that is genetically intractable. Herein, we report heterologous biosynthesis of MB from Methylocystis sp. strain SB2 in an alternative methanotroph, Methylosinus trichosporium OB3b, not only on methane but also on methanol. As a result, the strategy described herein not only facilitates enhanced MB production but also provides opportunities to construct various mutants to delineate the entire pathway of MB biosynthesis, as well as the creation of modified forms of MB that may have enhanced therapeutic value.

Copper, Iron, Cadmium, and Arsenic, All Generated in the Universe: Elucidating Their Environmental Impact Risk on Human Health Including Clinical Liver Injury

Humans are continuously exposed to various heavy metals including copper, iron, cadmium, and arsenic, which were specifically selected for the current analysis because they are among the most frequently encountered environmental mankind and industrial pollutants potentially causing human health hazards and liver injury. So far, these issues were poorly assessed and remained a matter of debate, also due to inconsistent results. The aim of the actual report is to thoroughly analyze the positive as well as negative effects of these four heavy metals on human health. Copper and iron are correctly viewed as pollutant elements essential for maintaining human health because they are part of important enzymes and metabolic pathways. Healthy individuals are prepared through various genetically based mechanisms to maintain cellular copper and iron homeostasis, thereby circumventing or reducing hazardous liver and organ injury due to excessive amounts of these metals continuously entering the human body. In a few humans with gene aberration, however, liver and organ injury may develop because excessively accumulated copper can lead to Wilson disease and substantial iron deposition to hemochromatosis. At the molecular level, toxicities of some heavy metals are traced back to the Haber Weiss and Fenton reactions involving reactive oxygen species formed in the course of oxidative stress. On the other hand, cellular homeostasis for cadmium and arsenic cannot be provided, causing their life-long excessive deposition in the liver and other organs. Consequently, cadmium and arsenic represent health hazards leading to higher disability-adjusted life years and increased mortality rates due to cancer and non-cancer diseases. For unknown reasons, however, liver injury in humans exposed to cadmium and arsenic is rarely observed. In sum, copper and iron are good for the human health of most individuals except for those with Wilson disease or hemochromatosis at risk of liver injury through radical formation, while cadmium and arsenic lack any beneficial effects but rather are potentially hazardous to human health with a focus on increased disability potential and risk for cancer. Primary efforts should focus on reducing the industrial emission of hazardous heavy metals.

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.

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.

Novel Gene-Correction-Based Therapeutic Modalities for Monogenic Liver Disorders

The majority of monogenic liver diseases are autosomal recessive disorders, with few being sex-related or co-dominant. Although orthotopic liver transplantation (LT) is currently the sole therapeutic option for end-stage patients, such an invasive surgical approach is severely restricted by the lack of donors and post-transplant complications, mainly associated with life-long immunosuppressive regimens. Therefore, the last decade has witnessed efforts for innovative cellular or gene-based therapeutic strategies. Gene therapy is a promising approach for treatment of many hereditary disorders, such as monogenic inborn errors. The liver is an organ characterized by unique features, making it an attractive target for in vivo and ex vivo gene transfer. The current genetic approaches for hereditary liver diseases are mediated by viral or non-viral vectors, with promising results generated by gene-editing tools, such as CRISPR-Cas9 technology. Despite massive progress in experimental gene-correction technologies, limitations in validated approaches for monogenic liver disorders have encouraged researchers to refine promising gene therapy protocols. Herein, we highlighted the most common monogenetic liver disorders, followed by proposed genetic engineering approaches, offered as promising therapeutic modalities.

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.

Optimized Trientine-dihydrochloride Therapy in Pediatric Patients With Wilson Disease: Is Weight-based Dosing Justified?

OBJECTIVES

The aim of the study was to investigate the efficacy and safety of trientine-dihydrochloride (TD) in pediatric patients with Wilson disease (WD) and the effect of different weight-based dosages on their clinical and biochemical outcome.

METHODS

We retrospectively reviewed the clinical data of 31 children with WD receiving TD therapy ages under 18 years at the time of diagnosis. Outcome measures included parameters of copper metabolism and liver function tests. To examine the impact of different weight-based dosages, 2 dosage subgroups were analyzed. Group 1 received less than 20 mg/kg TD per day, group 2 more than 20 mg · kg-1 · day-1.

RESULTS

Median follow-up was 60 (5-60) months in the total study group. During TD therapy, nonceruloplasmin-bound copper was reduced from mean 1.53 (0.01-6.95) at baseline to 0.62 (0.01-4.57) μmol/l. 24h-urinary copper excretion diminished to 1.85 (0.8-9.6) μmol/day approximating the therapeutic goal of 1.6 μmol/day. Seven of 31 patients (22.6%) required discontinuation of TD treatment, in 4 cases it was because of adverse events (ulcerative colitis, gingival and breast hypertrophy, hirsutism, elevation of transaminases).Investigations about weight-based dosage showed no significant difference of any laboratory parameter between the 2 cohorts. But in terms of clinical safety, adverse effects because of TD were only found in 6.7% of children in group 1 (<20 mg · kg-1 · day-1, median follow-up 60 [9-60] months), whereas in group 2 (>20 mg · kg-1 · day-1, median follow-up 60 [14-60] months), it was 63.6%.

CONCLUSIONS

TD proves to be an efficacious alternative chelating agent for children with WD. Weight-based dosages above the recommended 20 mg · kg-1 · day-1 may increase the rate of adverse effects in pediatric patients.

Observation on the changes of clinical symptoms, blood and brain copper deposition in Wilson disease patients treated with dimercaptosuccinic acid for 2 years

OBJECTIVE

To compare the clinical symptoms, brain copper deposition changes of Meso-2,3-dimercaptosuccinic acid (DMSA) and penicillamine therapy in patients with Wilson disease (WD) within 2 years.

METHODS

68 drug-naive patients with WD were enrolled. 10 WD patients treated with zinc gluconate alone were used as the control group. Neurological symptoms were scored using the modified Young Scale. Liver function tests, copper indices and sensitive weighted imaging (SWI) examination were collected. The values of corrected phase (CP) were collected. WD patients were treated with DPA (group 1) or DMSA (group 2) for two years, and followed up every 2 months.

RESULTS

The ratio of neurological improvement in group 2 was higher than that in group 1 (P = 0.029). Higher rate of neurologic worsening was noticed in patients treated with DPA vs DMSA (P = 0.039). The post-treatment neurological score of DMSA group was lower than that of Zn group (P = 0.037). Hepatic function in 63.3% of patients was stable, while 16.7% was improved, and 20% was deteriorated, after DMSA therapy. Urinary copper levels were lower 1 month (p = 0.032), 4 months (p = 0.041), 12 months (p = 0.037) after initiation of treatment in group 2 than in group 1. At the first year of treatment, the CP values in globus pallidus and substantia nigra in group 2 were higher than those in group 1 (P = 0.034,0.039). At the second year of treatment, the CP values of substantia nigra in group 2 were higher (P = 0.041). Discontinuation was more common in patients on DPA therapy (P = 0 0.032).

CONCLUSIONS

DMSA could remove metal from brain tissue faster than DPA. DMSA is effective for neurologic symptoms, while the outcome for hepatic symptoms is not entirely satisfactory. DMSA therapy is better tolerated than DPA.

Current anti-copper therapies in management of Wilson disease

In Wilson disease (WD) severity of disease can vary widely, depending on time of diagnosis. Early treatment can prevent the development of symptoms in patients. In all patients, lifelong medical treatment is indicated. Currently available medical regimens include the copper chelators for example D-penicillamine (DPA) or trientine (TETA), acting to increase copper excretion and zinc salts (ZS), which reduce copper uptake. In this chapter, we discuss considerations regarding choice of drug and safety limitations.

Pregnancy and Wilson disease: management and outcome of mother and newborns-experiences of a perinatal centre

Background

Wilson disease is an autosomal recessive genetic disorder affecting copper transport leading to hepatic and/or neuropsychiatric manifestation. Untreated Wilson disease in females may cause sub fertility or spontaneous miscarriage. Although the literature shows an increasing number of successful outcomes after treatment, pregnant patients with Wilson disease still need close monitoring and interdisciplinary management.

Methods

In a retrospective study patient charts of 32 pregnancies in 22 women with Wilson disease were reviewed retrospectively for the initial clinical manifestation, medical treatment prior and during pregnancy, maternal and fetal course and outcome.

Results

A total of 32 pregnancies in 22 patients were analyzed. The majority of our patients did not have any deterioration of symptoms of Wilson disease prior to and during pregnancy. One pregnant patient decided to stop her anticopper medications while pregnant with fatal outcome for both, mother and foetus. None of our newborns showed major birth defects or side effects in this cohort after maternal chelation treatment.

Conclusions

Reproductive status and pregnancies of women with Wilson disease may be problematic. Pregnant women need close monitoring and multidisciplinary management. Anticopper therapy during pregnancy and breast feeding are safe. Treatment should be maintained during pregnancy and the pregnant women should be treated by a multi-disciplinary team. With adequate medical treatment and close monitoring before and during pregnancy, a successful outcome of mother and newborn can be achieved.

Fanconi Syndrome

Fanconi syndrome, also known as the DeToni, Debré, Fanconi syndrome is a global dysfunction of the proximal tubule characterized by glucosuria, phosphaturia, generalized aminoaciduria, and type II renal tubular acidosis. Often there is hypokalemia, sodium wasting, and dehydration. In children, it typically is caused by inborn errors of metabolism, principally cystinosis. In adults, it is mainly caused by medications, exogenous toxins, and heavy metals. Treatment consists of treating the underlying cause and replacing the lost electrolytes and volume.

Altered zinc balance in the Atp7b-/- mouse reveals a mechanism of copper toxicity in Wilson disease

Wilson disease (WD) is an autosomal recessive disorder caused by mutation in the ATP7B gene that affects copper transport in the body. ATP7B mutation damages copper transporter function, ultimately resulting in excessive copper accumulation and subsequent toxicity in both the liver and brain. Mechanisms of copper toxicity, however, are not well defined. The Atp7b-/- mouse model is well-characterized and presents a hepatic phenotype consistent with WD. In this study, we found that the untreated Atp7b-/- mice accumulate approximately 2-fold excess hepatic zinc compared to the wild type. We used targeted transcriptomics and proteomics to analyze the molecular events associated with zinc and copper accumulation in the Atp7b-/- mouse liver. Altered gene expression of Zip5 and ZnT1 zinc transporters indicated a transcriptional homeostatic response, while increased copper/zinc ratios associated with high levels of metallothioneins 1 and 2, indicated altered Zn availability in cells. These data suggest that copper toxicity in Wilson disease includes effects on zinc-dependent proteins. Transcriptional network analysis of RNA-seq data reveals an interconnected network of transcriptional activators with over-representation of zinc-dependent and zinc-responsive transcription factors. In the context of previous research, these observations support the hypothesis that mechanisms of copper toxicity include disruption of intracellular zinc distribution in liver cells. The translational significance of this work lies in oral zinc supplementation in treatment for WD, which is thought to mediate protective effects through the induction of metallothionein synthesis in the intestine. This work indicates broader impacts of altered zinc-copper balance in WD, including global transcriptional responses and altered zinc balance in the liver.

Animal models of Wilson disease

Wilson disease (WD) is an autosomal recessive disorder of copper metabolism manifesting with hepatic, neurological and psychiatric symptoms. The limitations of the currently available therapy for WD (particularly in the management of neuropsychiatric disease), together with our limited understanding of key aspects of this illness (e.g. neurological vs. hepatic presentation) justify the ongoing need to study WD in suitable animal models. Four animal models of WD have been established: the Long-Evans Cinnamon rat, the toxic-milk mouse, the Atp7b knockout mouse and the Labrador retriever. The existing models of WD all show good similarity to human hepatic WD and have been helpful in developing an improved understanding of the human disease. As mammals, the mouse, rat and canine models also benefit from high homology to the human genome. However, important differences exist between these mammalian models and human disease, particularly the absence of a convincing neurological phenotype. This review will first provide an overview of our current knowledge of the orthologous genes encoding ATP7B and the closely related ATP7A protein in C. elegans, Drosophila and zebrafish (Danio rerio) and then summarise key characteristics of rodent and larger mammalian models of ATP7B-deficiency.

Pregnancy in Wilson's disease: Management and outcome

Wilson's disease (WD) is a rare inherited disorder of copper metabolism causing toxic hepatic and neural copper accumulation. Clinical symptoms vary widely, from asymptomatic disease to acute liver failure or chronic liver disease with or without neuropsychiatric symptoms. Continuation of specific medical treatment for WD is recommended during pregnancy, but reports of pregnancy outcomes in WD patients are sparse. In a retrospective, multicenter study, 282 pregnancies in 136 WD patients were reviewed. Age at disease onset, age at conception, and WD-specific treatments were recorded. Maternal complications during pregnancy, rate of spontaneous abortions, and birth defects were analyzed with respect to medical treatment during pregnancy. Worsening of liver function tests was evident during 16 of 282 (6%) pregnancies and occurred in undiagnosed patients as well as in those under medical treatment. Liver test abnormalities resolved in all cases after delivery. Aggravation of neurological symptoms during pregnancy was rare (1%), but tended to persist after delivery. The overall spontaneous abortion rate in the study cohort was 73 of 282 (26%). Patients with an established diagnosis of WD receiving medical treatment experienced significantly fewer spontaneous abortions than patients with undiagnosed WD (odds ratio, 2.853 [95% confidence interval, 1.634-4.982]). Birth defects occurred in 7 of 209 (3%) live births.

CONCLUSION

Pregnancy in WD patients on anticopper therapy is safe. The spontaneous abortion rate in treated patients was lower than that in therapy-naïve patients. Although the teratogenic potential of copper chelators is a concern, the rate of birth defects in our cohort was low. Treatment for WD should be maintained during pregnancy, and patients should be monitored closely for hepatic and neurological symptoms. (Hepatology 2018;67:1261-1269).

Methanobactin reverses acute liver failure in a rat model of Wilson disease

In Wilson disease (WD), functional loss of ATPase copper-transporting β (ATP7B) impairs biliary copper excretion, leading to excessive copper accumulation in the liver and fulminant hepatitis. Current US Food and Drug Administration- and European Medicines Agency-approved pharmacological treatments usually fail to restore copper homeostasis in patients with WD who have progressed to acute liver failure, leaving liver transplantation as the only viable treatment option. Here, we investigated the therapeutic utility of methanobactin (MB), a peptide produced by Methylosinus trichosporium OB3b, which has an exceptionally high affinity for copper. We demonstrated that ATP7B-deficient rats recapitulate WD-associated phenotypes, including hepatic copper accumulation, liver damage, and mitochondrial impairment. Short-term treatment of these rats with MB efficiently reversed mitochondrial impairment and liver damage in the acute stages of liver copper accumulation compared with that seen in untreated ATP7B-deficient rats. This beneficial effect was associated with depletion of copper from hepatocyte mitochondria. Moreover, MB treatment prevented hepatocyte death, subsequent liver failure, and death in the rodent model. These results suggest that MB has potential as a therapeutic agent for the treatment of acute WD.

Wilson disease: Health-related quality of life and risk for depression

BACKGROUND

Wilson disease is an autosomal recessive disorder of copper metabolism and requires lifelong medical treatment. Therefore, the analysis of quality of life has gathered more attention. Aims of this study were to examine risk for depression and health-related quality of life in patients suffering from Wilson disease.

METHODS

Sixty-eight patients were included in this retrospective cross sectional study. The Personal Health Questionnaire-9 Depression Scale was used to assess depression. The Short Form-36 Health Survey questionnaire was used to assess health-related quality of life.

RESULTS

The Personal Health Questionnaire-9 indicated that 21% (14/68) of patients were at risk for major depressive disorders (scores>10) and 35% (24/68) were at risk for mild depression (scores 5-9). Women had significantly lower life quality scores than men. Primary neurologic disease manifestation was associated with significantly lower total Short Form-36 and subdimension scores compared with primary hepatic or mixed presentation. Overall, patients with Wilson disease experienced higher quality of life than patients with other chronic liver diseases.

CONCLUSIONS

As patients with Wilson disease have a high risk for depressive disorders, active assessment for depression is mandatory. Patients with primary neurological symptoms are at higher risk for reduction of life quality.

Long-term metabolic correction of Wilson's disease in a murine model by gene therapy

BACKGROUND & AIMS

Wilson's disease (WD) is an autosomal recessively inherited copper storage disorder due to mutations in the ATP7B gene that causes hepatic and neurologic symptoms. Current treatments are based on lifelong copper chelating drugs and zinc salts, which may cause side effects and do not restore normal copper metabolism. In this work we assessed the efficacy of gene therapy to treat this condition.

METHODS

We transduced the liver of the Atp7b(-/-) WD mouse model with an adeno-associated vector serotype 8 (AAV8) encoding the human ATP7B cDNA placed under the control of the liver-specific α1-antitrypsin promoter (AAV8-AAT-ATP7B). After vector administration we carried out periodic evaluation of parameters associated with copper metabolism and disease progression. The animals were sacrificed 6months after treatment to analyze copper storage and hepatic histology.

RESULTS

We observed a dose-dependent therapeutic effect of AAV8-AAT-ATP7B manifested by the reduction of serum transaminases and urinary copper excretion, normalization of serum holoceruloplasmin, and restoration of physiological biliary copper excretion in response to copper overload. The liver of treated animals showed normalization of copper content and absence of histological alterations.

CONCLUSIONS

Our data demonstrate that AAV8-AAT-ATP7B-mediated gene therapy provides long-term correction of copper metabolism in a clinically relevant animal model of WD providing support for future translational studies.

Combination Therapy Using Chelating Agent and Zinc for Wilson's Disease

There is no clear international consensus regarding the optimal medication therapy for treating Wilson's disease (WD). This study systematically reviews the effectiveness of various medication therapies in common use, specifically focusing on preliminary findings concerning the combination of a chelating agent and zinc. A systematic PubMed search was executed to locate original studies on the effectiveness of commonly used medications for WD published between January 1989 and August 2014. The results were used to conduct a systematic review of studies on combination therapies. A total of 17 combination therapy studies involving 1056 patients were reviewed. These were analyzed in terms of data on effectiveness, adverse effects, and mortality. Results from a pooled analysis indicate that combination therapies for hepatic patients were significantly less effective than the same therapies for neurological manifestations (47.1 vs. 78.6 %; pooled relative risk ratio (RR): 0.63, 95 % confidence interval CI 0.43-0.94; p = 0.02). Data from a subgroup analysis show that the combination therapy of penicillamine plus zinc sulfate resulted in a significantly higher mortality rate compared to all other combination therapy types (16.3 vs. 4.7 %; RR: 3.51, 95 % CI 1.54-8.00; p < 0.001). The use of combination therapies involving zinc and a chelator should be carefully monitored with close clinical observations and frequent biochemical tests, especially for WD patients with hepatic manifestations.

Transition of gastroenterological patients from paediatric to adult care: A position statement by the Italian Societies of Gastroenterology

In 2013, four Italian Gastroenterological Societies (the Italian Society of Paediatric Gastroenterology, Hepatology and Nutrition, the Italian Society of Hospital Gastroenterologists and Endoscopists, the Italian Society of Endoscopy, and the Italian Society of Gastroenterology) formed a joint panel of experts with the aim of preparing an official statement on transition medicine in Gastroenterology. The transition of adolescents from paediatric to adult care is a crucial moment in managing chronic diseases such as celiac disease, inflammatory bowel disease, liver disease and liver transplantation. Improved medical treatment and availability of new drugs and surgical techniques have improved the prognosis of many paediatric disorders, prolonging survival, thus making the transition to adulthood possible and necessary. An inappropriate transition or the incomplete transmission of data from the paediatrician to the adult Gastroenterologist can dramatically decrease compliance to treatment and prognosis of a young patient, particularly in the case of severe disorders. For these reasons, the Italian gastroenterological societies decided to develop an official shared transition protocol. The resulting document discusses the factors influencing the transition process and highlights the main points to accomplish to optimize compliance and prognosis of gastroenterological patients during the difficult transition from childhood to adolescence and adulthood.

Increased Prevalence of Subcutaneous Lipomas in Patients With Wilson Disease

GOALS

To determine the prevalence and characteristics of lipomas in patients with Wilson disease.

BACKGROUND

Wilson disease is an autosomal recessive disorder resulting in copper accumulation in the liver and the central nervous tissue. Subcutaneous lipomas were often noted by the authors during clinical examinations of patients with Wilson disease. This is the first study to analyze the prevalence and progression of lipoma development in patients with Wilson disease.

STUDY

Eighty consecutive patients attending a tertiary care center were examined for the presence of subcutaneous lipomas.

RESULTS

Subcutaneous lipomas could be detected during the examination of 21 (26%) of the 80 patients with Wilson disease. Multiple subcutaneous lipomas were present in 16 (76%) of the 21 affected patients. Lipomas were mainly found on the extremities and the trunk. Neither initial presentation nor decoppering treatment influenced the presence or course of lipomas in these patients.

CONCLUSIONS

Subcutaneous lipoma formation is more common in patients with Wilson disease than in the general population. We suggest that the presence of lipomas contributes to the differential diagnosis of Wilson disease.

Wilson's disease and other neurological copper disorders

The copper metabolism disorder Wilson's disease was first defined in 1912. Wilson's disease can present with hepatic and neurological deficits, including dystonia and parkinsonism. Early-onset presentations in infancy and late-onset manifestations in adults older than 70 years of age are now well recognised. Direct genetic testing for ATP7B mutations are increasingly available to confirm the clinical diagnosis of Wilson's disease, and results from biochemical and genetic prevalence studies suggest that Wilson's disease might be much more common than previously estimated. Early diagnosis of Wilson's disease is crucial to ensure that patients can be started on adequate treatment, but uncertainty remains about the best possible choice of medication. Furthermore, Wilson's disease needs to be differentiated from other conditions that also present clinically with hepatolenticular degeneration or share biochemical abnormalities with Wilson's disease, such as reduced serum ceruloplasmin concentrations. Disordered copper metabolism is also associated with other neurological conditions, including a subtype of axonal neuropathy due to ATP7A mutations and the late-onset neurodegenerative disorders Alzheimer's disease and Parkinson's disease.

Communication between the N and C termini is required for copper-stimulated Ser/Thr phosphorylation of Cu(I)-ATPase (ATP7B)

The Wilson disease protein ATP7B exhibits copper-dependent trafficking. In high copper, ATP7B exits the trans-Golgi network and moves to the apical domain of hepatocytes where it facilitates elimination of excess copper through the bile. Copper levels also affect ATP7B phosphorylation. ATP7B is basally phosphorylated in low copper and becomes more phosphorylated ("hyperphosphorylated") in elevated copper. The functional significance of hyperphosphorylation remains unclear. We showed that hyperphosphorylation occurs even when ATP7B is restricted to the trans-Golgi network. We performed comprehensive phosphoproteomics of ATP7B in low versus high copper, which revealed that 24 Ser/Thr residues in ATP7B could be phosphorylated, and only four of these were copper-responsive. Most of the phosphorylated sites were found in the N- and C-terminal cytoplasmic domains. Using truncation and mutagenesis, we showed that inactivation or elimination of all six N-terminal metal binding domains did not block copper-dependent, reversible, apical trafficking but did block hyperphosphorylation in hepatic cells. We showed that nine of 15 Ser/Thr residues in the C-terminal domain were phosphorylated. Inactivation of 13 C-terminal phosphorylation sites reduced basal phosphorylation and eliminated hyperphosphorylation, suggesting that copper binding at the N terminus propagates to the ATP7B C-terminal region. C-terminal mutants with either inactivating or phosphomimetic substitutions showed little effect upon copper-stimulated trafficking, indicating that trafficking does not depend on phosphorylation at these sites. Thus, our studies revealed that copper-dependent conformational changes in the N-terminal region lead to hyperphosphorylation at C-terminal sites, which seem not to affect trafficking and may instead fine-tune copper sequestration.

Regulation of ATP-gated P2X channels: from redox signaling to interactions with other proteins

SIGNIFICANCE

The family of purinergic P2X receptors (P2XRs) is a part of ligand-gated superfamily of channels activated by extracellular adenosine-5'-triphosphate. P2XRs are present in virtually all mammalian tissues as well as in tissues of other vertebrate and nonvertebrate species and mediate a large variety of functions, including fast transmission at central synapses, contraction of smooth muscle cells, platelet aggregation, and macrophage activation to proliferation and cell death.

RECENT ADVANCES

The recent solving of crystal structure of the zebrafish P2X4.1R is a major advance in the understanding of structural correlates of channel activation and regulation. Combined with growing information obtained in the post-structure era and the reinterpretation of previous work within the context of the tridimensional structure, these data provide a better understanding of how the channel operates at the molecular levels.

CRITICAL ISSUES

This review focuses on the relationship between redox signaling and P2XR function. We also discuss other allosteric modulation of P2XR gating in the physiological/pathophysiological context. This includes the summary of extracellular actions of trace metals, which can be released to the synaptic cleft, pH decrease that happens during ischemia and inflammation, and calcium, an extracellular and intracellular messenger.

FUTURE DIRECTIONS

Our evolving understanding of activation and regulation of P2XRs is helpful in clarifying the mechanism by which these channels trigger and modulate cellular functions. Further research is required to identify the signaling pathways contributing to the regulation of the receptor activity and to develop novel and receptor-specific allosteric modulators, which could be used in vivo with therapeutic potential.

Genetic diseases that predispose to early liver cirrhosis

Inherited liver diseases are a group of metabolic and genetic defects that typically cause early chronic liver involvement. Most are due to a defect of an enzyme/transport protein that alters a metabolic pathway and exerts a pathogenic role mainly in the liver. The prevalence is variable, but most are rare pathologies. We review the pathophysiology of such diseases and the diagnostic contribution of laboratory tests, focusing on the role of molecular genetics. In fact, thanks to recent advances in genetics, molecular analysis permits early and specific diagnosis for most disorders and helps to reduce the invasive approach of liver biopsy.

Therapies for ataxias

OPINION STATEMENT

Ataxia can originate from many genetic defects, but also from nongenetic causes. To be able to provide treatment, the first step is to establish the right diagnosis. Once the cause of the ataxia is defined, some specific treatments may be available. For example, the nongenetic ataxias that arise from vitamin deficiencies can improve following treatment. In most cases, however, therapies do not cure the disease and are purely symptomatic. Physiotherapy and occupational therapy are effective in all type of ataxias and often remain the most efficient treatment option for these patients to maximize their quality of life.

[Complexity of the diagnosis of Wilson disease in clinical practice: our experience in 15 patients]

BACKGROUND

Wilson disease (WD) is an inherited disorder that causes copper (Cu) accumulation, leading to mainly liver, neurological and/or psychiatric manifestations. In the absence of some of the typical features, diagnosis of WD is difficult and is based on the combination of clinical, biochemical and genetic testing. The aim of this study was to illustrate the complexity of the approach to WD in daily clinical practice.

METHODS

We retrospectively analyzed the medical records of patients with WD, including the clinical presentation, histological and biochemical findings, and follow up after treatment. We also carried out genetic testing, and the Leipzig diagnostic score was applied.

RESULTS

We included 15 patients. Four were symptomatic, with liver (n=1), neurological (n=1), psychiatric (n=1) and mixed clinical manifestations (n=1), and 11 were presymptomatic, with elevated transaminases (n=8) and family study (n=3). We observed Kayser-Fleischer ring in 2 patients, both without neurologic symptoms. Ceruloplasmin ≤ 5 mg/dL was present in 73%, and 24-hour urinary Cu> 100 μg in 40%. Liver Cu was >250 μg/g.d.t. in 85% of the patients. The final diagnosis of WD was given by genetic testing (ATP7B gene mutations) in 5 patients with minimal disease features, including one symptomatic patient (psychiatric symptoms). We identified 5 previously reported mutations (p.M645R, p.R827W, p.H1069Q, p.P768L and p.G869R) and 3 unpublished mutations (p.L1313R, p.I1311T and p.A1179D); the most frequent mutation was p.M645R. After treatment, biochemical parameters (transaminases, urinary cooper) and symptoms improved, except in patients with neurological and psychiatric manifestations.

CONCLUSIONS

Our series illustrates the important role of genetic testing in the diagnosis of WD. The identification of the p.M645R mutation in most of our patients should be kept in mind in the molecular analysis of the ATP7B gene in our region.

Distinct phenotype of a Wilson disease mutation reveals a novel trafficking determinant in the copper transporter ATP7B

Wilson disease (WD) is a monogenic autosomal-recessive disorder of copper accumulation that leads to liver failure and/or neurological deficits. WD is caused by mutations in ATP7B, a transporter that loads Cu(I) onto newly synthesized cupro-enzymes in the trans-Golgi network (TGN) and exports excess copper out of cells by trafficking from the TGN to the plasma membrane. To date, most WD mutations have been shown to disrupt ATP7B activity and/or stability. Using a multidisciplinary approach, including clinical analysis of patients, cell-based assays, and computational studies, we characterized a patient mutation, ATP7B(S653Y), which is stable, does not disrupt Cu(I) transport, yet renders the protein unable to exit the TGN. Bulky or charged substitutions at position 653 mimic the phenotype of the patient mutation. Molecular modeling and dynamic simulation suggest that the S653Y mutation induces local distortions within the transmembrane (TM) domain 1 and alter TM1 interaction with TM2. S653Y abolishes the trafficking-stimulating effects of a secondary mutation in the N-terminal apical targeting domain. This result indicates a role for TM1/TM2 in regulating conformations of cytosolic domains involved in ATP7B trafficking. Taken together, our experiments revealed an unexpected role for TM1/TM2 in copper-regulated trafficking of ATP7B and defined a unique class of WD mutants that are transport-competent but trafficking-defective. Understanding the precise consequences of WD-causing mutations will facilitate the development of advanced mutation-specific therapies.

A review and current perspective on Wilson disease

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

Outcome and development of symptoms after orthotopic liver transplantation for Wilson disease

BACKGROUND

Wilson disease (WD) is an autosomal recessive copper storage disease resulting in hepatic and neurologic dysfunction. Liver transplantation is an effective treatment for fulminant cases for patients with chronic liver disease. Reports on the outcome of neuropsychiatric symptoms after orthotopic liver transplantation (OLT) are limited.

AIM

To assess the course of neuropsychiatric and hepatic symptoms after liver transplantation for Wilson disease

METHODS

Nineteen patients with Wilson disease received liver transplantation and were followed prospectively from 2005 to 2010 for the development of hepatic, neurological and psychiatric symptoms.

RESULTS

Eight patients (all female) were transplanted for acute liver failure and eleven patients for chronic liver failure. Patient survival rates one and five yr after transplantation were 78% and 65%, respectively. Of the surviving patients, hepatic symptom scores improved in all patients and neurological symptom scores improved in all but one patient after OLT compared to the time of initial diagnosis and compared to pre-OLT status. Psychiatric symptoms showed moderate improvements.

CONCLUSION

Survival after OLT for Wilson disease with end-stage liver disease is excellent. Overall, neuropsychiatric symptoms improved after transplantation, substantiating arguments for widening of the indication for liver transplantation in symptomatic neurologic Wilson disease patients with stable liver function.

An update on laboratory diagnosis of liver inherited diseases

Liver inherited diseases are a group of genetically determined clinical entities that appear with an early chronic liver involvement. They include Wilson's disease (hepatolenticular degeneration), hereditary hemochromatosis, and alpha-1-antitrypsin deficiency. In addition, cystic fibrosis, although it is not specifically a liver disease, may cause a severe liver involvement in a significant percentage of cases. For all these pathologies, the disease gene is known, and molecular analysis may contribute to the unequivocal diagnosis. This approach could avoid the patient invasive procedures and limit complications associated with a delay in diagnosis. We review liver inherited diseases on the basis of the genetic defect, focusing on the contribution of molecular analysis in the multistep diagnostic workup.

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

BACKGROUND & AIMS

Wilson disease is a genetic copper storage disorder that causes hepatic and neurologic symptoms. Chelating agents (D-penicillamine, trientine) are used as first-line therapies for symptomatic patients, but there are few data from large cohorts. We assessed the safety of D-penicillamine and trientine therapy and outcomes of patients with Wilson disease.

METHODS

We performed a retrospective analysis of data on 380 patients with Wilson disease from tertiary care centers in Germany and Austria, and 25 additional patients from the EUROWILSON registry. Chelator-based treatment regimens were analyzed for their effect on neurologic and hepatic symptoms and for adverse events that led to discontinuation of therapy (Kaplan-Meier estimation; data were collected for a mean of 13.3 y after therapy began).

RESULTS

Changes in medication were common, resulting in analysis of 471 chelator monotherapies (326 patients receiving D-penicillamine and 141 receiving trientine). Nine of 326 patients treated with D-penicillamine and 3 of 141 patients given trientine underwent liver transplantation. Adverse events leading to discontinuation of treatment were more frequent among those receiving D-penicillamine than trientine (P = .039). Forty-eight months after therapy, hepatic deterioration was reported in only 4 of 333 patients treated initially with a chelating agent. Hepatic improvements were observed in more than 90%, and neurologic improvements were observed in more than 55%, of therapy-naive patients, and values did not differ significantly between treatments. However, neurologic deterioration was observed less frequently in patients given D-penicillamine first (6 of 295) than those given trientine first (4 of 38; P = .018).

CONCLUSIONS

Chelating agents are effective therapies for most patients with Wilson disease; D-penicillamine and trientine produce comparable outcomes, although D-penicillamine had a higher rate of adverse events. Few patients receiving chelation therapy had neurologic deterioration, which occurred more frequently in patients who received trientine.

Ceruloplasmin is a potential biomarker for aGvHD following allogeneic hematopoietic stem cell transplantation

Acute graft-versus-host-disease (aGvHD) is the major cause of non-relapse mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Recently, diagnostic biomarkers for aGvHD have been shown to play important roles in evaluating disease status and mortality risk after allo-HSCT. To identify plasma biomarkers for aGvHD with high sensitivity and specificity, a quantitative proteomic approach using 8-plex isobaric tags for relative and absolute quantitation (8-plex iTRAQ) was employed to screen differentially expressed proteins in peripheral blood before and after the onset of aGvHD. Four target proteins, ceruloplasmin (CP), myeloperoxidase (MPO), complement factor H (CFH), and alpha-1-acid glycoprotein (AGP), were chosen for preliminary validation with enzyme linked immunosorbent assay (ELISA) in 20 paired samples at both the time of diagnosis of aGvHD and the time of complete response. The most promising candidate, ceruloplasmin, was further validated at fixed time points after allo-HSCT and during aGvHD. The plasma ceruloplasmin levels were significantly increased during the period of aGvHD onset and were markedly decreased as aGvHD resolved. The plasma ceruloplasmin levels at different time points post-transplant in the aGvHD (+) group were significantly higher than those in the aGvHD (-) group (p<0.001). The elevation of ceruloplasmin level in patients with active aGvHD was independent of infection status. Patients whose ceruloplasmin levels were elevated above 670 μg/ml at 7, 14 and 21 days after allo-HSCT had a remarkably increased probability of subsequently developing aGvHD. In conclusion, our results suggest that plasma ceruloplasmin is a potential plasma biomarker of aGvHD, and it also has prognostic value for risk-adapted prophylaxis during the consecutive time points monitored in the first month after allo-HSCT.

D-penicillamine treatment of copper-associated hepatitis in Labrador retrievers

d-penicillamine is effectively used in the lifelong treatment of copper toxicosis in Bedlington terriers and Wilson's disease in humans. A complex form of copper-associated hepatitis has recently been characterized in the Labrador retriever. The aims of this study were to evaluate the effectiveness of d-penicillamine treatment for copper-associated hepatitis in this breed, to study the effects on hepatic copper, iron and zinc concentrations, and to evaluate parameters to predict optimal duration of treatment. Forty-three client owned Labrador retrievers that were diagnosed with increased hepatic copper were treated with d-penicillamine and underwent at least one follow-up examination including a liver biopsy for histopathological scoring of inflammatory lesions. Hepatic copper, iron and zinc concentrations were determined in the initial and follow-up biopsies by instrumental neutron activation analysis. The influence of initial hepatic copper concentration, sex, age, d-penicillamine formulation and the occurrence of side effects were investigated for their influence on hepatic copper concentration after a certain period of treatment by generalized mixed modelling. d-penicillamine proved to be effective in reducing hepatic copper concentration and associated inflammatory lesions. Parameters derived from the model can be used to estimate the necessary duration of d-penicillamine treatment for Labrador retrievers with increased hepatic copper concentration. Continuous, lifelong d-penicillamine treatment is not recommended in this breed, as there may be a risk for hepatic copper and zinc deficiency.

Non-invasive evaluation of hepatic manifestation in Wilson disease with transient elastography, ARFI, and different fibrosis scores

OBJECTIVE

Noninvasive investigation of liver fibrosis with ultrasound-based elastography and laboratory-based fibrosis indices have been established in various chronic liver diseases within the last years. We aimed to evaluate feasibility and diagnostic value of transient elastography (TE), acoustic radiation force impulse imaging (ARFI), and different serologic fibrosis indices in Wilson's disease (WD).

MATERIALS AND METHODS

TE and ARFI were performed in 50 Wilson patients. In addition, AST/Platelet Ratio Index (APRI), FIB-4, and Forns score were calculated. Hepatic fibrosis was classified by a clinical score.

RESULTS

Of the 50 Wilson patients 41 had hepatic manifestation of WD. TE results were significantly increased in advanced hepatic fibrosis (7.0 ± 2.2 kPa; p < 0.05) and cirrhosis (10.1 ± 6.73 kPa; p < 0.05) compared to individuals without hepatic manifestation (5.0 ± 1.4 kPa). Right liver lobe ARFI (R-ARFI) values were only increased in cirrhotic patients (1.43 ± 0.28 vs. 1.19 ± 0.14 m/s; p < 0.05). The cutoff values to best discriminate cirrhosis were 6.1 kPa for TE and 1.29 m/s for R-ARFI. Left lobe ARFI failed to provide additional diagnostic benefit. Elastography methods displayed a significant correlation with APRI, FIB-4, and Forns indices (Pearson's rho > 0.33; p < 0.03).

CONCLUSIONS

TE displayed a gradual increase between different stages of hepatic manifestation in WD and could significantly discriminate cirrhosis. The TE cutoff for cirrhosis may be clinically more relevant than the R-ARFI value.