Penicillamine as a controversial treatment for Wilson's disease

Copper nutrition and biochemistry and human (patho)physiology

The essential trace mineral copper plays important roles in human physiology and pathophysiology. Disruption of copper homeostasis may underlie the development of ischemic heart disease, and connective tissue and neurodegenerative disorders. Copper also likely participates in the host response to bacterial infection and is further implicated more broadly in regulating immunity. Recent studies further associate copper with disruption of lipid homeostasis, as is frequently seen in, for example, non-alcoholic fatty liver disease (NAFLD). Moreover, continuing investigation of copper chaperones has revealed new roles for these intracellular copper-binding proteins. Despite these (and many other) significant advances, many questions related to copper biology remain unanswered. For example, what are the most sensitive and specific biomarkers of copper status, and which ones are useful in marginal (or "sub-clinical" copper deficiency)? Further research on this topic is required to inform future investigations of copper metabolism in humans (so the copper status of study participants can be fully appreciated). Also, are current recommendations for copper intake adequate? Recent studies suggest that overt copper deficiency is more common than once thought, and further, some have suggested that the copper RDAs for adults may be too low. Additional human balance and interventional studies are necessary and could provide the impetus for reconsidering the copper RDAs in the future. These and myriad other unresolved aspects of copper nutrition will undoubtedly be the focus of future investigation.

Wilson Disease Presenting With Acute on Chronic Liver Failure: A Single-Center Experience of Outcome and Predictors of Mortality in 68 Patients

BACKGROUND AND AIMS

Acute on chronic liver failure (ACLF) is an emerging entity whose unique pathogenesis, presentation, and outcome are different from those with decompensated cirrhosis. Patients with Wilson disease (WD) often present with ACLF. The outcome in this setting and predictors of mortality have not been well delineated. We describe the clinical features, laboratory characteristics, and prognostic factors in patients with WD with ACLF. We compared the outcome in those without criteria for ACLF.

PATIENTS AND METHODS

We analyzed the admission characteristics of 68 patients with WD presenting with features of ACLF among a cohort of WD patients from 1997 to 2017. WD was diagnosed as per European association for the study of the liver (EASL)/Leipzig criteria and ACLF by the Asia-Pacific Association of Study of Liver and World Gastroenterology Organization consensus criteria. Factors associated with mortality were analyzed by univariate followed by multivariate analysis and receiver operating characteristic curve.

RESULTS

Of the 272 patients with WD, 68 fulfilled criteria for ACLF. The mean age was 14.4 years (Range 5-42 years). Males constituted 38/68 (56%). Acute viral or drug induced hepatitis as precipitating factors was seen in 11.7%. Forty-nine patients (49/67; 73%) died including 30/32 (93.8%) with encephalopathy and 45/62 (72.6%) with ascites. Prognostic factors on univariate analysis significant for mortality included encephalopathy, international normalized ratio, white blood cell count and model for end-stage liver disease (MELD) score. On multivariate analysis, only encephalopathy was significant with 82% accuracy in differentiating survivors versus non-survivors. Post mortem liver biopsy in 21 patients and explant biopsy in 2 patients showed features of cirrhosis in all.

CONCLUSIONS

WD with ACLF is associated with a high mortality Precipitating factors such as viral and drug-induced hepatitis was seen in 11.7% patients. Liver histology in patients subjected to biopsy showed cirrhosis in all. Only encephalopathy is a prognostic marker of non-survival with an accuracy of 82%.

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.

Early Onset of Wilson Disease: Diagnostic Challenges

OBJECTIVES

The aim of the study was to analyze the clinical presentations, diagnosis, and treatment of patients ages ≤5 years with early onset Wilson disease (WD).

METHODS

Data from 143 pediatric patients with WD treated at our center between January 1996 and November 2015 were retrospectively analyzed.

RESULTS

A review of the 143 pediatric patients with WD identified 21 (10 girls, 11 boys) with first symptoms or abnormal liver function test results at age ≤5 years. The diagnosis of WD was confirmed in 8 patients younger than 5 years. At baseline the mean serum alanine aminotransferase level was 222 U/L and the mean serum aspartate aminotransferase level was 130 U/L. The mean serum ceruloplasmin concentration in 16 tested patients was <20 mg/dL. Of the 15 patients who underwent urinary copper excretion testing, 8 had levels between 40 and 100 μg/day, with only 4 having levels >100 μg/day. Liver copper quantification was >250 μg/g dry weight in 16 patients. The most common mutation was p.H1069Q, with compound heterozygosity in 5 patients and homozygosity in 9. Sixteen patients were treated with zinc salts and 5 with D-penicillamine. Both treatments were effective, with no serious side effects observed after 3 to 24 months.

CONCLUSIONS

WD can present as early as 2 years of age. Because biochemical tests may be less sensitive in very young children, diagnoses may require a combination of tests. If molecular tests are inconclusive, liver copper content should be measured.

Wilson's disease: the 60th anniversary of Walshe's article on treatment with penicillamine

This historical review describes Professor Walshe's seminal contribution to the treatment of Wilson's disease on the 60th anniversary of his pioneering article on penicillamine, the first effective treatment for the condition.

Wilson's disease

In the almost 100 years since Wilson's description of the illness that now bears his name, tremendous advances have been made in our understanding of this disorder. The genetic basis for Wilson's disease - mutation within the ATP7B gene - has been identified. The pathophysiologic basis for the damage resulting from the inability to excrete copper via the biliary system with its consequent gradual accumulation, first in the liver and ultimately in the brain and other organs and tissues, is now known. This has led to the development of effective diagnostic and treatment modalities that, although they may not eliminate the disorder, do provide the means for efficient diagnosis and effective amelioration if carried out in a dedicated and persistent fashion. Nevertheless, Wilson's disease remains both a diagnostic and treatment challenge for physician and patient. Its protean clinical manifestations make diagnosis difficult. Appropriate diagnostic evaluations to confirm the diagnosis and institute treatment can be confusing. In this chapter, the clinical manifestations, diagnostic evaluation, and treatment approaches for Wilson's disease are discussed.

Diagnosis of Wilson's disease: a comprehensive review

Wilson's disease is an autosomal recessive disorder of copper metabolism. The culprit gene is ATP7B. The worldwide prevalence is about 1 in 30,000, which may vary by population. Higher prevalence rates were reported using more sensitive screening techniques and pilot population screening. Typical presentations include neuropsychiatric and hepatic dysfunction, whereas atypical presentations are protean. Diagnosis relies on a high clinical suspicion, typical neurological symptoms, presence of Kayser-Fleischer rings, and reduced serum ceruloplasmin concentration. The conventional value of < 0.20 g/l is not a universal diagnostic value. Age of the subjects and analytical variations should be considered when interpreting these levels. Patients with inconclusive findings require further investigations such as 24 h urinary free-copper excretion, penicillamine challenge test, liver copper measurement, and detection of gene mutations. Direct molecular diagnosis remains the most decisive tool. Other tests such as non-ceruloplasmin-bound copper are unreliable. Potential pitfalls and limitations of these diagnostic markers are critically reviewed in this paper. The mainstays of therapy are trientine, penicillamine, and/or zinc. Liver transplantation is lifesaving for those with advanced disease. Ceruloplasmin oxidase activity and serum free-copper concentration should be monitored in patients on long-term de-coppering therapy to prevent iatrogenic copper deficiency.

Enfermedad de Wilson con afectación neurológica grave: respuesta al tratamiento combinado con trientina y acetato de cinc

In patients with Wilson's disease and neurological manifestations, treatment with D-penicillamine can cause worsening of neurological symptoms, usually in the first few weeks of treatment. Because the neurological damage can be severe and irreversible, the use of D-penicillamine is controversial, and several authors believe that it should be avoided. Studies of the use of ammonium tetrathiomolybdate as an alternative chelating agent for the initial treatment of neurologic Wilson's disease are still in the experimental phase. Published experience on the simultaneous use of trientine, another chelating agent, and zinc, which blocks intestinal absorption of copper, is promising but limited. We present the case of a 17 year-old boy with severe neurologic Wilson's disease that had first presented six years previously. The patient showed a complete recovery after six months of treatment with a combination of trientine and zinc acetate.

Neuromodulator role of zinc and copper during prolonged ATP applications to P2X4 purinoceptors

To further elucidate the modulator role of trace metals such as zinc and copper on the activity of nucleotide purinoceptors, the action of these metals was assessed during prolonged ATP applications to rat P2X(4) purinoceptors expressed in Xenopus laevis oocytes. Application of ATP for 3 min resulted in a biphasic effect; a fast transient peak was followed by a slower stable current component with similar pharmacological and biophysical characteristics. The application of 1-300 microM Cu(2+) inhibited both current components to a comparable extent; likewise, Zn(2+) facilitated to a similar degree the transient and the slower stable current components. Carnosine (Car), cysteine (Cys), histidine (His), and the metal chelator, penicillamine, prevented the inhibitory action of Cu(2+); the Zn(2+) facilitation was not prevented by neither Car nor His but by either bathophenantroline or Cys, revealing metal selectivity. While the noncompetitive Cu(2+) inhibition appears to decrease channel conductance, Zn(2+) likely increases ATP affinity independently of the activation state of the purinoceptor. These results strongly support the notion that trace metals modulate the activity of the P2X(4) purinoceptor and could become relevant during continual activity of a P2X(4) purinoceptor-containing synapse.

Childhood dystonia

Childhood dystonias are a heterogeneous group of disorders with strong inherited basis. This review describes the clinical characteristics, classification, genetic basis, pathophysiology, biochemistry, pathology, and treatment of dystonias, including the primary dystonias, the dystonia-plus syndromes, secondary dystonias, and heredodegenerative disorders. Conditions discussed in detail include idiopathic torsion dystonia, dopa-responsive dystonia, Wilson's disease, myoclonus dystonia, rapid-onset dystonia parkinsonism, neurodegeneration with brain iron accumulation (Hallervorden-Spatz syndrome), mitochondrial dystonias, Niemann-Pick type C, and neuroacanthocytosis.

Inherited movement disorders

The inherited movement disorders comprise a rapidly growing category of human disease. Advances in genetics have led to the identification of the gene mutation in Huntington's disease and three different gene mutations, which may lead to Parkinson's disease. In addition, gene mutations have been identified in less common movement disorders including Wilson's disease, Hallervorden-Spatz syndrome, paroxysmal kinesogenic choreoathetosis, neuroacanthocytosis, and some forms of dystonia. This article summarizes what is known about the genetic mutations that cause these movement disorders, as well as the clinical features of each disease and the symptomatic treatments currently available.

Dystonia and its disorders

Dystonia is a movement disorder characterized by sustained muscle contractions, frequently causing twisting and repetitive movements or abnormal postures. The term dystonia does not signify a single disease, but instead describes a symptom and sign that may be part of many disorders with a variety of causes. Dystonia may be classified by age of onset, distribution of symptoms, or by etiology. An increasing number of genetic forms of dystonia have been recognized and the findings have advanced knowledge of underlying neural mechanisms of pathogenesis. Options for treatment of dystonia include pharmacological therapy, botulinum toxin injection, or neurosurgical procedures.