MRI and oxidative stress markers in neurological worsening of Wilson disease following penicillamine

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.

Differences in the Time Course of Recovery from Brain and Liver Dysfunction in Conventional Long-Term Treatment of Wilson Disease

BACKGROUND

The aim of this study was to demonstrate that both neurological and hepatic symptoms respond to copper chelation therapy in Wilson disease (WD). However, the time course of their recovery is different.

METHODS

Eighteen patients with neurological WD from a single specialized center who had been listed for liver transplantation during the last ten years and two newly diagnosed homozygous twins were recruited for this retrospective study. The mean duration of conventional treatment was 7.3 years (range: 0.25 to 36.2 years). A custom Wilson disease score with seven motor items, three non-motor items, and 33 biochemical parameters of the blood and urine, as well as the MELD score, was determined at various checkup visits during treatment. These data were extracted from the charts of the patients.

RESULTS

Treatment was initiated with severity-dependent doses (≥900 mg) of D-penicillamine (DPA) or triethylene-tetramin-dihydrochloride (TRIEN). The motor score improved in 10 and remained constant in 8 patients. Worsening of neurological symptoms was observed only in two patients who developed comorbidities (myasthenia gravis or hemispheric stroke). The neurological symptoms continuously improved over the years until the majority of patients became only mildly affected. In contrast to this slow recovery of the neurological symptoms, the MELD score and liver enzymes had already started to improve after 1 month and rapidly improved over the next 6 months in 19 patients. The cholinesterase levels continued to increase significantly (p < 0.0074) even further. One patient whose MELD score indicated further progression of liver disease received an orthotopic liver transplantation 3 months after the diagnosis of WD and the onset of DPA treatment.

CONCLUSIONS

Neurological and hepatic symptoms both respond to copper chelation therapy. For patients with acute liver failure, the first 4 months are critical. This is the time span in which patients have to wait either for a donor organ or until significant improvement has occurred under conventional therapy. For patients with severe neurological symptoms, it is important that they are treated with fairly high doses over several years.

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.

The effects of copper sulfate on the structure and function of the rat cerebellum: A stereological and behavioral study

Copper (Cu) is a vital trace element that acts as a cofactor of proteins and enzymes in many molecular pathways including the central nervous system. The accumulation or deficiency of copper could alter neuronal function and lead to neuronal degeneration and brain dysfunction. Intake of high levels of copper can also cause copper toxicosis that affects the brain structure and function. Despite clinical and experimental data indicating the association between abnormal copper homeostasis and brain dysfunction, the effects of copper on cerebellum have remained poorly understood. Hence, this study aimed to evaluate the effects of copper sulfate on the cerebellum via stereological and behavioral methods in rats. Male rats (Sprague-Dawley) were divided to three groups. The rats in the control group orally received distilled water, while those in the Cu groups received 1 mM (159 mg/L) or 8 mM (1272 mg/L) copper sulfate by oral gavage solved in distilled water daily for 4 weeks. Then, the rotarod performance test was recorded and the cerebellum was prepared for stereological assessments. The Cu-administered rats (1 and 8 mM) exhibited a significant reduction in the total volumes of the cerebellum structures. The total number of the cells in the cerebellar cortex and deep cerebellar nuclei were significantly decreased via Cu in a dose-dependent manner. Furthermore, the length of nerve fibers and the number of spines per nerve fiber decreased significantly in the Cu groups. These changes were correlated to the animals' motor performance impairment in the rotarod test. The findings suggested that copper toxicity induced motor performance impairments in the rats, which could be attributed to its deleterious effects on the cerebellum structure.

Safety profile of D-penicillamine: a comprehensive pharmacovigilance analysis by FDA adverse event reporting system

BACKGROUND

D-penicillamine (D-pen) is a copper-chelating drug and has immune-modulatory properties. D-pen is used to treat rheumatoid arthritis, Wilson's disease, and kidney stones (cystinuria). However, associated adverse events (AEs) of D-pen treatment are frequent and often serious. Therefore, a comprehensive assessment of the safety profile of D-pen is urgently needed.

RESEARCH DESIGN AND METHODS

We identified and analyzed AEs associated with D-pen between April-1970 to July-2020 from the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) databases and calculated the reported odds ratio (ROR) with 95% confidence intervals (CI) using the disproportionality analysis.

RESULTS

A total of 9,150,234 AEs related to drugs were reported in the FAERS database, of which 542 were related to D-Pen. We report that D-pen was associated with dystonia (ROR: 20.52; 95%CI: 12.46-33.80), drug hypersensitivity (ROR: 5.42; 95%CI: 3.72-7.90), pancytopenia (ROR: 10.20; 95%CI: 5.61-18.56), joint swelling (ROR: 9.07; 95%CI: 5.51-14.94), renal-impairment (ROR: 6.68; 95%CI: 3.67-12.15), dysphagia (ROR: 5.05; 95%CI: 2.76-8.89), aggravation of condition (ROR: 4.16; 95%CI: 2.60-6.67), congestive cardiac failure (ROR: 4.04; 95%CI: 2.22-7.35), peripheral edema (ROR: 3.77; 95%CI: 2.17-6.55), tremor (ROR: 3.46; 95%CI: 2.00-6.01), pyrexia (ROR: 3.46; 95%CI: 2.00-6.01), and gait disturbance (ROR: 2.41; 95%CI: 1.29-4.52).

CONCLUSIONS

Patients taking D-pen require close monitoring of renal function, blood counts, immunity, liver, cardiac function, and neurological function. D-pen suppresses immune system which maximizes the risk of infection.

Persistence with medical treatment for Wilson disease in China based on a single center's survey research

BACKGROUND

Wilson's disease (WD) is one of the few hereditary diseases that can be successfully treated with medicines. We conduct this survey research to assess treatment persistence among patients with WD and try to identify what factors affect the treatment persistence.

METHODS

We employed WeChat which is the most popular social software in China to carry out this anonymous questionnaire research. The questionnaire included medication adherence scale. We also collected available medical records related to demographic and clinical characteristics. All the patients were divided into group of persistence with drug treatment (PDT) and nonpersistence with drug treatment (n-PDT).

RESULTS

We collected 242 qualified questionnaires. Only 66.5% of patients were PDT during the mean 12.6 years of follow-up. In PDT group, better outcomes were observed: improvement (78.3%) and no change (16.1%) versus those in n-PDT (55.6%; and 28.4%, respectively). In PDT group, only nine patients deteriorated (6.8%) in comparison with 13 patients in n-PDT (16.0%). The adverse events (AEs) in PDT group were significantly less than those in n-PDT group. There were no significant differences in clinical type, gender, age, education level, and family knowledge about WD between the two groups. There were significant differences in AEs and family position toward treatment.

CONCLUSION

Medication Adherence of Chinese WD patients was low. One third of the patients (33.5%) were unable to PDT, and it had an important negative effect on clinical outcome. AEs and family support had an important impact on treatment persistence.

Combined dimercaptosuccinic acid and zinc treatment in neurological Wilson's disease patients with penicillamine-induced allergy or early neurological deterioration

The clinical data of safety and efficacy of a combined treatment with dimercaptosuccinic acid (DMSA) and Zinc with 2 years’ follow-up in 60 neurological Wilson’s disease (WD) patients was retrospectively analyzed. All the patients included in the present study were newly diagnosed and initialized with D-penicillamine (DPA) treatment but were found to have either neurological deterioration or allergy, and their treatment was switched to a combined treatment of DMSA and Zinc. Fifty-one patients (85%) had the neurological symptoms improved 1 and 2 years after treatment, 7 (11.67%) experienced a stable neurological condition, and 2 (3.33%) suffered deterioration of neurological symptoms. No early neurological deterioration was observed in all patients. Twenty-five percent patients experienced mild adverse reactions which did not require a discontinuation of the DMSA and Zinc treatment. Our study confirmed the safety and efficacy of the combined DMSA and Zinc therapy as an initial and probably long-term treatment in neurological WD patients.

Switching Pharmacological Treatment in Wilson Disease: Case Report and Recommendations

Background. Available treatments for Wilson disease (WD) prevent longterm complications of copper accumulation. Current anti-copper agents include zinc salts, penicillamine, and trientine. Patients with WD may switch between the agents for a number of reasons. Due to the different mechanisms of action between the copper chelators and zinc salts, transitioning could require a period of overlap and increased monitoring. There are no large studies that investigate the best transition strategies between agents. In this article, we review the treatments for WD and how to monitor for treatment efficacy. Case Summary. The patient had been diagnosed with WD for over 20 years prior to establishing care in our Hepatology Clinic. During his initial course, he was transitioned from penicillamine to zinc due to evidence suggesting penicillamine had greater adverse effects in the long term. Later, he was switched to trientine. His liver enzymes and 24-hour urine copper were monitored. During these years, he intermittently had some financial hardship, requiring him to be on penicillamine rather than trientine. He also had developed acute kidney injury. Overall, his liver disease remained under control and he never had signs of decompensated cirrhosis, but had fluctuations of liver enzymes over the years. Conclusion. Anti-copper treatment for WD has to be tailored to medication side effects profile, patient's chronic and emerging comorbidities, as well as costs. Transitioning regimens is often challenging, and it requires closer monitoring, with no predictors of response.

[Diagnostics of Wilson's disease]

Wilson's disease is a rare genetic but treatable metabolic disorder which has a favorable prognosis when diagnosed early and treated adequately. Therefore, knowledge of this rare clinical condition and a reliable diagnosis are indispensable. The diagnostic work-up is initiated in cases of unexplained acute or chronic liver disease and/or an extrapyramidal motor disturbance occurring mostly between the 5th and 45th years of life. Manifestations with initial symptoms have occasionally been observed at an age younger than 1 year and later than 70 years. Immediate biochemical and genetic examinations for early diagnosis are essential. Further test methods, such as liver and transcranial sonography, cerebral magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET), ¹²³I-beta-CIT and ¹²³I-iodobenzamide (IBZM) single photon emission computed tomography (SPECT), electrophysiology as well as fine motor tests are unspecific but can be used to test for organ damage and for monitoring of progress. Immediate initiation of a therapy is required and justified on the basis of a confirmed diagnosis.

Advances in Treatment of Wilson Disease

Background

Wilson disease (WD) is an inherited neurometabolic disorder that results in excessive copper deposition in the liver and the brain, affecting children and young adults. Without treatment the disease is invariably fatal. Though treatments for WD have been available since the 1950s, the disease continues to be associated with considerable morbidity and mortality because of missed diagnosis, and delayed or inadequate treatment. In this paper we survey WD-related literature in order to review recent advances in WD treatment.

Methods

We performed a literature search using the PubMed database for articles relating to WD and its medical treatment. We reviewed the articles, and cross-references of relevant articles, to summarize the current practices for treatment of WD.

Results

The survey shows that if WD is properly treated, in most patients the liver can be stabilized, even severe neurological disability reversed, and patients can resume normal lives.

Discussion

Medical treatment for WD includes use of copper chelators (penicillamine, trientine, dimercaprol, dimercaptopropane sulfonate, and ammonium tetrathiomolybdate) and drugs that decrease gastrointestinal copper absorption. Our knowledge of the treatment approaches has benefited from the large systematic clinical studies that have been conducted over the last decade. For each drug used to treat WD, we surveyed its development, indication for use, dosing, efficacy, and adverse effects.

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

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

Effects of copper on viability and functional properties of hippocampal neurons in vitro

Copper (Cu²⁺) is an essential metal presented in the mammalian brain and released from synaptic vesicles following neuronal depolarization. However, the disturbance of Cu²⁺ homeostasis results in neurotoxicity. In our study we performed for the first time a combined functional investigation of cultured hippocampal neurons under Cu²⁺ exposure, its effect on spontaneous spike activity of hippocampal neuronal network cultured on multielectrode array (MEA), and development of long-term potentiation (LTP) in acute hippocampal slices in the presence of Cu²⁺. Application of 0.2mM CuCl₂ for 24h reduced viability of cultured neurons to 40±6%, whereas 0.01mM CuCl₂ did not influence significantly on the neuronal survival. However, exposure to the action of 0.01mM Cu²⁺ resulted in pronounced reduction of network spike activity and abolished LTP induced by high-frequency stimulation of Schaffer's collaterals in CA1 pyramidal neurons of hippocampal slices. Antioxidant Trolox, the hydrosoluble vitamin E analogue, prevented neurotoxic effect and alterations of network activity under Cu²⁺ exposure, but didn't change the impairment of LTP in Cu²⁺-exposured hippocampal slices. We hypothesized that spontaneous network neuronal activity probably is one of the potential targets of Cu²⁺-induced neurotoxicity, in which free radicals can be involved. At the same time, it may be suggested that Cu²⁺-induced alterations of long-lasting trace processes (like LTP) are not mediated by oxidative damage.

Chemosensitivity of U251 Cells to the Co-treatment of D-Penicillamine and Copper: Possible Implications on Wilson Disease Patients

D-Penicillamine (PA), a copper chelator, and one of the recommended drugs for treatment of Wilson disease (WD) has been reported to worsen the symptoms of patients with neurologic presentations. However, the cause of this paradoxical response has not been fully elucidated and requires further investigations. Accordingly, we have studied the in vitro effect of Copper (Cu) and/or PA treatment on human glioblastoma U251 cells as an in vitro model of Cu cytotoxicity. Treatment of U251 cells with either Cu or PA exerted no significant effect on their morphology, viability or ROS level. In contrast, co-treatment with Cu-PA caused a decrease in viability, altered glutathione and ceruloplasmin expression coupled with marked increase in ROS; depolarization of mitochondrial membrane potential; and an increase in Sub G0 phase; along with alpha-Fodrin proteolysis. These findings along with the absence of LDH release in these assays, suggest that combined Cu-PA exposure induced apoptosis in U251 cells. In addition, pre-/or co-treatment with antioxidants showed a protective effect, with catalase being more effective than N-acetyl cysteine or trolox in restoring viability and reducing generated ROS levels. By comparison, a similar analysis using other cell lines showed that rat PC12 cells were resistant to Cu and/or PA treatment, while the neuroblastoma cell line SH-SY5Y was sensitive to either compound alone, resulting in decreased viability and increased ROS level. Taken together, this study shows that glioblastoma U251 cells provide a model for Cu-PA cytotoxicity mediated by H₂O₂. We postulate that PA oxidation in presence of Cu yields H₂O₂ which in turn permeates the plasma membrane and induced apoptosis. However, other cell lines exhibited different responses to these treatments, potentially providing a model for cell type- specific cytotoxic responses in the nervous system. The sensitivity of different neural and glial cell types to Cu-PA treatment may therefore underlie the neurologic worsening occurring in some PA-treated WD patients. Our results also raise the possibility that the side effects of PA treatment might be reduced or prevented by administering antioxidants.

Wilson’s disease: A review of what we have learned

Wilson’s disease (WD), which results from the defective ATP7B protein product, is characterized by impaired copper metabolism and its clinical consequences vary from an asymptomatic state to fulminant hepatic failure, chronic liver disease with or without cirrhosis, neurological, and psychiatric manifestations. A high grade of suspicion is warranted to not miss cases of WD, especially less florid cases with only mild elevation of transaminases, or isolated neuropsychiatric involvement. Screening in first and second relatives of index cases is mandatory, and treatment must commence upon establishment of diagnosis. Treatment strategies include chelators such as D-penicillamine and trientine, while zinc salts act as inductors of methallothioneins, which favor a negative copper balance and a reduction of free plasmatic copper. As an orphan disease, research is lacking in this field, especially regarding therapeutic strategies which are associated with better patient compliance and which could eventually also reverse established injury.

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

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