Hemolytic anemia in Wilson disease: clinical findings and biochemical mechanisms

Clinical observation and risk assessment after splenectomy in hepatolenticular degeneration patients associated with hypersplenism

Background

Both hepatolenticular degeneration (HLD) and viral hepatitis B (HBV) can cause hypersplenism, but whether splenectomy is needed or can be performed in HLD patients associated with hypersplenism is still controversial. At present, HLD combined with hypersplenism has not been listed as the indication of splenectomy.

Objective

This study aimed to investigate the efficacy, risks, and postoperative complications of splenectomy in HLD patients associated with hypersplenism.

Methods

We retrospectively analyzed the clinical data of 180 HLD patients with hypersplenism who underwent splenectomy in the Department of General Surgery, First Affiliated Hospital of Anhui University of Traditional Chinese Medicine, from January 2001 to December 2015. To evaluate the efficacy of splenectomy, the hemogram of white blood cells (WBC), red blood cells (RBC), platelets (PLT), and the liver function indexes including alanine aminotransferase, aspartate aminotransferase, and total bilirubin were recorded before surgery and 1, 3, 5, 7, and 14 days after surgery. In addition, the clinical data of 142 HBV patients with hypersplenism who underwent splenectomy over the same period were also recorded and compared with that of HLD patients. In particular, aiming to assess the risks of splenectomy in HLD, we also compared postoperative complications and 36-month mortality between the two groups.

Result

The level of WBC, RBC, and PLT were all elevated after splenectomy in both the HLD group and the HBV group. However, there was no significant difference in the variation of hemogram after splenectomy between the two groups (P > 0.05). Similarly, the variation of liver function indexes showed no statistical difference between the two groups. In terms of the incidence of postoperative complications including abdominal bleeding, pancreatic leakage, portal vein thrombosis treatment, incision infection, lung infection, and 36-month mortality, there were no significant differences between the two groups.

Conclusion

After splenectomy, the hemogram as well as liver function in the HLD group improved a lot and showed a consistent tendency with that in the HBV group. Meanwhile, compared to the HBV group, there was no significant difference in the incidence of postoperative complications in the HLD group. All these results indicate that splenectomy in HLD patients combined with hypersplenism is completely feasible and effective.

Management Perspective of Wilson's Disease: Early Diagnosis and Individualized Therapy

Wilson's disease (WD) is an inherited disease caused by mutations in ATP7B and is characterized by the pathological accumulation of copper in the liver and brain. Common clinical manifestations of WD include a wide range of liver disease and neurological symptoms. In some patients, psychiatric symptoms may be the only manifestation at the time of diagnosis. The clinical features of WD are highly variable and can mimic any disease of internal medicine. Therefore, for unexplained medical diseases, the possibility of WD should not be ignored. Early diagnosis and treatment can improve the prognosis of WD patients and reduce disability and early death. Gene sequencing is becoming a valuable method to diagnose WD, and if possible, all WD patients and their siblings should be genetically sequenced. Copper chelators including D-penicillamine, trientine, and dimercaptosuccinic acid can significantly improve the liver injury and symptoms of WD patients but may have a limited effect on neurological symptoms. Zinc salts may be more appropriate for the treatment of asymptomatic patients or for the maintenance treatment of symptomatic patients. High-quality clinical trials for the drug treatment of WD are still lacking, therefore, individualized treatment options for patients are recommended. Individualized treatment can be determined based on the clinical features of the WD patients, efficacy and adverse effects of the drugs, and the experience of the physician. Liver transplantation is the only effective method to save patients with acute liver failure or with severe liver disease who fail drug treatment.

Wilson disease

Wilson disease (WD) is a potentially treatable, inherited disorder of copper metabolism that is characterized by the pathological accumulation of copper. WD is caused by mutations in ATP7B, which encodes a transmembrane copper-transporting ATPase, leading to impaired copper homeostasis and copper overload in the liver, brain and other organs. The clinical course of WD can vary in the type and severity of symptoms, but progressive liver disease is a common feature. Patients can also present with neurological disorders and psychiatric symptoms. WD is diagnosed using diagnostic algorithms that incorporate clinical symptoms and signs, measures of copper metabolism and DNA analysis of ATP7B. Available treatments include chelation therapy and zinc salts, which reverse copper overload by different mechanisms. Additionally, liver transplantation is indicated in selected cases. New agents, such as tetrathiomolybdate salts, are currently being investigated in clinical trials, and genetic therapies are being tested in animal models. With early diagnosis and treatment, the prognosis is good; however, an important issue is diagnosing patients before the onset of serious symptoms. Advances in screening for WD may therefore bring earlier diagnosis and improvements for patients with WD.

Oxidative stress, eryptosis and anemia: a pivotal mechanistic nexus in systemic diseases

The average lifespan of circulating erythrocytes usually exceeds hundred days. Prior to that, however, erythrocytes may be exposed to oxidative stress in the circulation which could cause injury and trigger their suicidal death or eryptosis. Oxidative stress activates Ca²⁺ -permeable nonselective cation channels in the cell membrane, thus, stimulating Ca²⁺ entry and subsequent cell membrane scrambling resulting in phosphatidylserine exposure and activation of Ca²⁺ -sensitive K⁺ channels leading to K⁺ exit, hyperpolarization, Cl^- exit, and ultimately cell shrinkage due to loss of KCl and osmotically driven water. While the mechanistic link between oxidative stress and anemia remains ill-defined, several diseases such as diabetes, hepatic failure, malignancy, chronic kidney disease and inflammation have been identified to display both increased oxidative stress as well as eryptosis. Recent compelling evidence suggests that oxidative stress is an important perpetrator in accelerating erythrocyte loss in different systemic conditions and an underlying mechanism for anemia associated with these pathological states. In the present review, we discuss the role of oxidative stress in reducing erythrocyte survival and provide novel insights into the possible use of antioxidants as putative antieryptotic and antianemic agents in a variety of systemic diseases.

Other organ involvement and clinical aspects of Wilson disease

Wilson disease (WD) is a rare disorder of copper metabolism that presents mainly with hepatic and neuropsychiatric features. Copper accumulates not only in the liver and brain, but also in other organs. Liver injury can also be the cause of secondary impairment of other tissues. Therefore, the clinical manifestation of WD may be renal, cardiac, skin, osteoarticular, or endocrinologic and include other organ disturbances. Renal abnormalities include tubular dysfunction (e.g., renal tubular acidosis, aminoaciduria) and nephrolithiasis. Bone demineralization is a common manifestation in patients with WD. Cardiac injury may include arrhythmia, cardiomyopathy, and autonomic dysfunction. Different endocrine system manifestations, such as infertility or repeated miscarriages, growth and puberty disturbances, and hypoparathyroidism, are observed. Other important clinical aspects of WD include pancreas involvement, immunologic abnormalities, the presence of lipomas, and skin changes. Although other organ involvement is not common in WD and usually not severe, delayed diagnosis may lead to irreversible changes in organs and tissues. Therefore, awareness of other possible WD presentations is important in the differential diagnosis of WD.

Effect of Copper on l-Cysteine/l-Cystine Influx in Normal Human Erythrocytes and Erythrocytes of Wilson's Disease

Wilson's disease is a disease of abnormal copper metabolism in which free serum copper level is raised. The objective of the study was to determine, whether in Wilson disease, l-cysteine/l-cystine influx into RBC was decreased or not and the specific amino acid transporter affected by copper in normal human RBC. For l-cysteine/l-cystine influx, ten untreated cases, ten treated cases and ten age and sex matched healthy controls were recruited. To study the effect of copper on l-cysteine/l-cystine influx in RBC, 15 healthy subjects were selected. RBC GSH and l-cysteine/l-cystine influx were estimated by Beautler's and Yildiz's method respectively. In untreated cases, l-cysteine/l-cystine influx and erythrocyte GSH level were decreased showing that elevated level of free copper in serum or media decreased l-cysteine/l-cystine influx in human RBC. Copper treatment inhibited L amino acid transporter in normal RBC specifically.

Chemical-specific health consultation for chromated copper arsenate chemical mixture: port of Djibouti

The Agency for Toxic Substances and Disease Registry (ATSDR) prepared this health consultation to provide support for assessing the public health implications of hazardous chemical exposure, primarily through drinking water, related to releases of chromated copper arsenate (CCA) in the port of Djibouti. CCA from a shipment, apparently intended for treating electric poles, is leaking into the soil in the port area. CCA is a pesticide used to protect wood against decay-causing organisms. This mixture commonly contains chromium(VI) (hexavalent chromium) as chromic acid, arsenic(V) (pentavalent arsenic) as arsenic pentoxide and copper (II) (divalent copper) as cupric oxide, often in an aqueous solution or concentrate. Experimental studies of the fate of CCA in soil and monitoring studies of wood-preserving sites where CCA was spilled on the soil indicate that the chromium(VI), arsenic and copper components of CCA can leach from soil into groundwater and surface water. In addition, at CCA wood-preserving sites, substantial concentrations of chromium(VI), arsenic and copper remained in the soil and were leachable into water four years after the use of CCA was discontinued, suggesting prolonged persistence in soil, with continued potential for leaching. The degree of leaching depended on soil composition and the extent of soil contamination with CCA. In general, leaching was highest for chromium(VI), intermediate for arsenic and lowest for copper. Thus, the potential for contamination of sources of drinking water exists. Although arsenic that is leached from CCA-contaminated soil into surface water may accumulate in the tissues of fish and shellfish, most of the arsenic in these animals will be in a form (often called fish arsenic) that is less harmful. Copper, which leaches less readily than the other components, can accumulate in tissues of mussels and oysters. Chromium is not likely to accumulate in the tissues of fish and shellfish. Limited studies of air concentrations during cleanup of CCA-contaminated soil at wood- preserving sites showed that air levels of chromium(VI), arsenic and copper were below the occupational standards. Workers directly involved in the repackaging, containment or cleanup of leaking containers of CCA or of soil saturated with CCA, however, may be exposed to high levels of CCA through direct dermal contact, inhalation of aerosols or particulates and inadvertent ingestion. Few studies have been conducted on the health effects of CCA. CCA as a concentrated solution is corrosive to the skin eyes and digestive tract. Studies of workers exposed to CCA in wood-preserving plants have not found adverse health effects in these workers, but the studies involved small numbers of workers and therefore are not definitive. People exposed to very high levels of CCA, from sawing wood that still had liquid CCA in it or from living in a home contaminated with ash containing high levels of chromium(VI), arsenic and copper, experienced serious health effects including nosebleeds, digestive system pain and bleeding, itching skin, darkened urine, nervous system effects such as tingling or numbness of the hands and feet and confusion, and rashes or thickening and peeling of the skin. These health effects of the mixture are at least qualitatively reflective of the health effects of the individual components of CCA (arsenic, chromium(VI) and copper). For a given mixture, the critical effects of the individual components are of particular concern, as are any effects in common that may become significant due to additivity or interactions among the components. Effects of concern for CCA, based on the known effects of the individual components, include cancer (arsenic by the oral route, arsenic and chromium(VI) by the inhalation route), irritant or corrosive effects (all three mixture components), the unique dermal effects of arsenic, neurologic effects (arsenic and chromium(VI), and hematologic, hepatic and renal effects (all three components). Because arsenic, chromium(VI), and copper components affect some of the same target organs, they may have additive toxicity toward those organs. Few studies have investigated the potential toxic interactions among the components (arsenic, chromium(VI) and copper) of CCA. The available interaction studies and also possible mechanisms of interaction were evaluated using a weight-of-evidence approach. The conclusion is that there is no strong evidence that interactions among the components of CCA will result in a marked increase in toxicity. This conclusion reflects a lack of well designed interaction studies as well as uncertainties regarding potential mechanisms of interaction. Confidence in the conclusion is low. Workers exposed to high levels of CCA during cleanup of leaking containers of CCA or soil heavily contaminated with CCA should wear protective clothing and respirators if air concentrations of arsenic are above 10 μg/m3. In addition, they should not eat, drink or use tobacco products during exposure to CCA, and should thoroughly wash after skin contact with CCA and before eating, drinking, using tobacco products or using restrooms. When protective clothing becomes contaminated with CCA, it should be changed, and the contaminated clothing should be disposed off in a manner approved for pesticide disposal. Workers should leave all protective clothing, including work shoes and boots, at the workplace, so that CCA will not be carried into their cars and homes, which would endanger other people. People not involved in the cleanup of the CCA and who are not wearing protective clothing should be prevented from entering contaminated areas. Leaking containers of CCA must be repackaged and contained to prevent direct exposure of on-site personnel; and contaminated soil needs to be removed to prevent the CCA from leaching into surface water and groundwater, thereby contaminating sources of drinking water.

Diagnosis and management of fulminant Wilson's disease: a single center's experience

BACKGROUND

Medical therapy is rarely effective in patients with fulminant Wilson's disease (FWD). Liver transplantation is limited by the lack of donor liver in most patients with FWD at the time of diagnosis. New Wilson's index, model for end-stage liver disease (MELD) and Child-Pugh score are useful tools for decision-making of liver transplantation; however, none of them is an independent decisive tool. It is worthwhile to explore a more effective and practical therapeutic strategy and reevaluate the prediction systems for patients with FWD.

METHODS

Nine patients with FWD associated with hemolytic crisis and fulminant hepatic failure (FHF) were investigated. The clinical presentation, prognostic score and medical therapies of the patients were analyzed.

RESULTS

In 7 of the 9 patients with FWD who received the comprehensive therapy of corticosteroid, copper-chelating agent (dimercaptopropansulfonate sodium) and therapeutic plasma exchange (TPE), 6 patients recovered from FHF. The remaining one had been improved through the comprehensive therapy but died of septicemia 51 days later. Two patients with spontaneous bacterial peritonitis (SBP) died from liver failure in three or five hospital days without plasma exchange or chelating therapy. All of the 9 patients with FWD presented with acute hepatic failure, severe jaundice and mild to severe hemolytic anemia. No marked difference in the incidence of severe hemolytic anemia was detected between the survival and deceased groups. However, the incidence and the degree of hepatic encephalopathy (HE) in the non-survival group were higher than those in the survival group. Unlike the deceased group, the survival group had no complications induced by bacterial infection. Compared to new Wilson's index, Child-Pugh score and MELD score, the variation of prothrombin activity (PTA) between the survival and deceased groups was more evident.

CONCLUSION

For patients with FWD, the episode of severe hepatic encephalopathy or/and spontaneous bacterial peritonitis indicates worse prognosis, and PTA is a recommendable predictor. An emergent liver transplantation should be considered for patients whose PTA is below 20%, or for those with severe HE or/and SBP. The comprehensive therapy of corticosteroid, copper-chelating agent and TPE is effective for patients without SBP and whose PTA is higher than 20%.

Liver transplantation for Wilson's disease

Although Wilsons's disease (WD) may be treated with copper chelation (to remove copper) or zinc salts (to prevent absorption) to alleviate or prevent symptom development in most patients, there are WD patients for whom medical therapy is inadequate and survival would be unlikely without liver transplantation. Liver transplantation is indicated for the ∼5% of WD patients with acute liver failure as the first presentation of disease, most commonly in the second decade of life, or those who present with end-stage liver disease and severe hepatic insufficiency, most commonly in the third and fourth decades. Liver transplantation restores normal biliary copper excretion (thereby preventing disease recurrence) and promotes removal of copper from extrahepatic sites. Outcomes of liver transplantation for WD are excellent, including both cadaveric and living donors.

Therapeutic plasmapheresis as a bridge to liver transplantation in fulminant Wilson disease

Wilson disease is an autosomal recessive disorder of copper metabolism that leads to the accumulation of copper mainly in the liver, cornea, brain, and kidney. Rarely, Wilson disease can present as fulminant hepatic failure with direct antiglobulin test-negative hemolytic anemia and renal failure. In the absence of liver transplantation, this disease is uniformly fatal because medical therapy is ineffective. This report describes the successful use of plasmapheresis for a patient with fulminant Wilson disease as a bridge to transplantation. Five daily therapeutic plasmapheresis procedures using fresh frozen plasma as a replacement fluid were performed over 6 days. Serum copper, urinary copper excretion, and hemolysis were significantly reduced and renal function improved. The patient's clinical status improved and she remained clinically stable until a liver transplant was possible. Plasmapheresis can be a successful medical treatment in fulminant Wilson disease and should be considered as a therapeutic measure to stabilize a patient by decreasing serum copper, reducing hemolysis, and helping to prevent renal tubular injury from copper and copper complexes until liver transplantation is possible.

Liver cell death and anemia in Wilson disease involve acid sphingomyelinase and ceramide

Wilson disease is caused by accumulation of Cu(2+) in cells, which results in liver cirrhosis and, occasionally, anemia. Here, we show that Cu(2+) triggers hepatocyte apoptosis through activation of acid sphingomyelinase (Asm) and release of ceramide. Genetic deficiency or pharmacological inhibition of Asm prevented Cu(2+)-induced hepatocyte apoptosis and protected rats, genetically prone to develop Wilson disease, from acute hepatocyte death, liver failure and early death. Cu(2+) induced the secretion of activated Asm from leukocytes, leading to ceramide release in and phosphatidylserine exposure on erythrocytes, events also prevented by inhibition of Asm. Phosphatidylserine exposure resulted in immediate clearance of affected erythrocytes from the blood in mice. Accordingly, individuals with Wilson disease showed elevated plasma levels of Asm, and displayed a constitutive increase of ceramide- and phosphatidylserine-positive erythrocytes. Our data suggest a previously unidentified mechanism for liver cirrhosis and anemia in Wilson disease.

Erythrocyte metabolism and antioxidant status of patients with Wilson disease with hemolytic anemia

Wilson disease (WD) is an autosomal recessive disorder due to the defect in ATP7B gene characterized by excessive accumulation of copper in the liver with progressive hepatic damage and subsequent redistribution to various extrahepatic tissues including the brain, kidneys, and cornea. Strikingly, the total serum copper concentration is always low in WD, even though the non-ceruloplasmin copper level is still expected to be high. To assess the role of free radical reactions catalyzed by non-ceruloplasmin copper, we investigated erythrocyte metabolism and oxidative stress as a mechanism for hemolysis in eight WD patients during episodes of acute hemolysis and compared them with eight follow-up cases of WD on d-penicillamine therapy and eight healthy, age-matched children. Elevated levels of non-ceruloplasmin copper were found in all the WD patients during an episode of hemolytic anemia. There was marked inhibition in erythrocyte enzymes, namely, hexokinase, total adenosine triphosphatase (ATPase), and glucose-6-phosphate dehydrogenase (G-6-PD) from WD patients compared with patients on penicillamine and healthy children, indicating altered erythrocyte metabolism during a hemolytic crisis. Antioxidant status was also found to be compromised as is evident from decreased glutathione (GSH) levels, decreased antioxidant enzymes (namely, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase), increased lipid peroxidation, and deranged plasma antioxidants. Uric acid showed maximum decrease followed by ascorbic acid. These findings suggest that the free radical production by elevated non-ceruloplasmin copper through transition metal catalyzed reactions leads to oxidative injury resulting in altered erythrocyte metabolism and severely compromised antioxidant status of WD patients during hemolytic anemia.

Haemolytic onset of Wilson disease in a patient with homozygous truncation of ATP7B at Arg1319

We describe a 19-year-old woman with haemolytic anaemia and thrombocytopenia as the initial manifestation of Wilson disease (WD). There are two reasons for reporting such an improbable case. First, it emphasizes the importance of recognizing atypical clinical presentations of potentially lethal recessive traits for which therapy is available. Second, it shows that, even in a monogenic disorder like WD, the phenotype cannot be extrapolated from the mutated genotype in a simple fashion; this patient had a relatively late-onset form of WD despite homozygosity for a genetic lesion leading to an apparent complete loss of function of the WD copper transporter.

The antioxidant effect of DL-alpha-lipoic acid on copper-induced acute hepatitis in Long-Evans Cinnamon (LEC) rats

The Long-Evans Cinnamon (LEC) rats, due to a genetic defect, accumulate excess copper (Cu) in the liver in a manner similar to patients with Wilson's disease and spontaneously develop acute hepatitis with severe jaundice. In this study we examined the protective effect of DL-alpha-Lipoic acid (LA) against acute hepatitis in LEC rats. LA was administered to LEC rats by gavage in doses of 10, 30 and 100 mg/kg five times per week, starting at 8-weeks-old and continuing till 12-weeks-old. Although LA had little effect against the increases in serum transaminase activities, it suppressed the loss of body weight and prevented severe jaundice in a dose-dependent manner. Antioxidant system analyses in liver showed that LA treatment significantly suppressed the inactivations of catalase and glutathione peroxidase, and the induction of heme oxygenase-1, an enzyme which is inducible under oxidative stress. Furthermore, LA showed dose-dependent suppressive effect against increase in nonheme iron contents of both cytosolic and crude mitochondrial fractions in a dose-dependent manner. Although at the highest dose, LA slightly suppressed the accumulation of Cu in crude mitochondrial fraction, it had no effect on the accumulation of Cu in cytosolic fraction. While LA completely suppressed the increase in lipid peroxidation (LPO) in the microsomal fraction at the highest dose, the suppressive effect against LPO in crude mitochondrial fractions was slight. From these results, it is concluded that LA has antioxidant effects at the molecular level against the development of Cu-induced hepatitis in LEC rats. Moreover, mitochondrial oxidative damage might be involved in the development of acute hepatitis in LEC rats.

Intracellular generation of superoxide by copper sulphate in Escherichia coli

Oxidative stress exerted by superoxide-generating agents such as paraquat triggers induction of the soxRS regulon of E. coli. In the system, SoxR protein is the superoxide-sensitive activator of the soxS gene. We found that copper sulphate (CuSO4) is a powerful inducer of soxS in a manner tightly dependent on both a functional soxR gene and the presence of molecular oxygen. E. coli strain lacking either superoxide dismutases or oxidative DNA repair enzymes was hypersensitive to killing by CuSO4. These results suggest that superoxide may be generated intracellularly by CuSO4 treatment, and that the generation may be involved in the Cu cytotoxicity.

Copper-specific damage in human erythrocytes exposed to oxidative stress

Ascorbate and complexes of Cu(II) and Fe(III) are capable of generating significant levels of oxygen free radicals. Exposure of erythrocytes to such oxidative stress leads to increased levels of methemoglobin and extensive changes in cell morphology. Cu(II) per mole is much more effective than Fe(III). However, isolated hemoglobin is oxidized more rapidly and completely by Fe(III)- than by Cu(II)-complexes. Both Fe(III) and Cu(II) are capable of inhibiting a number of the key enzymes of erythrocyte metabolism. The mechanism for the enhanced activity of Cu(II) has not been previously established. Using intact erythrocytes and hemolysates we demonstrate that Cu(II)-, but not Fe(III)-complexes in the presence of ascorbate block NADH-methemoglobin reductase. Complexes of Cu(II) alone are not inhibitory. The relative inability of Fe(III)-complexes and ascorbate to cause methemoglobin accumulation is not owing to Fe(III) association with the membrane, or its failure to enter the erythrocytes. The toxicity of Cu(II) and ascorbate appears to be a result of site-specific oxidative damage of erythrocyte NADH-methemoglobin reductase and the enzyme's subsequent inability to reduce the oxidized hemoglobin.

Hepatic iron deprivation prevents spontaneous development of fulminant hepatitis and liver cancer in Long-Evans Cinnamon rats

Several clinical studies have suggested that excess hepatic iron accumulation is a progressive factor in some liver diseases including chronic viral hepatitis and hemochromatosis. However, it is not known whether iron-induced hepatotoxicity may be directly involved in hepatitis, cirrhosis, and liver cancer. The Long-Evans Cinnamon (LEC) rat, which accumulates excess copper in the liver as in patients with Wilson's disease, is of a mutant strain displaying spontaneous hemolysis, hepatitis, and liver cancer. We found previously that LEC rats harbored an additional abnormality: accumulation of as much iron as copper in the liver. In the present study, we compared the occurrence of hepatitis and liver cancer in LEC rats fed an iron-deficient diet (ID) with those in rats fed a regular diet (RD). The RD group showed rapid increments of hepatic iron concentrations as the result of hemolysis, characteristics of fulminant hepatitis showing apoptosis, and a 53% mortality rate. However, no rats in the ID group died of fulminant hepatitis. Hepatic iron, especially "free" iron concentration and the extent of hepatic fibrosis in the ID group were far less than those of the RD group. At week 65, all rats in the RD group developed liver cancer, whereas none did in the ID group. These results suggest that the accumulation of iron, possibly by virtue of synergistic radical formation with copper, plays an essential role in the development of fulminant hepatitis, hepatic fibrosis, and subsequent hepatocarcinogenesis in LEC rats.

Wilson's disease: current status

OBJECTIVE

To review current concepts about the pathogenesis, clinical manifestations, and treatment of Wilson's disease, with an emphasis on recent developments.

DATA IDENTIFICATION

Published information was identified using MEDLINE and through extensive manual searching of bibliographies in identified sources.

RESULTS

The basic biochemical alteration responsible for deranged hepatobiliary copper homeostasis in Wilson's disease has yet to be identified. The gene for Wilson's disease has been mapped to chromosome 13, but the function of its gene product has not yet been determined. The clinical manifestations of Wilson's disease are varied and often nonspecific and include a range of hepatic, neurologic, and psychiatric findings. Penicillamine remains the drug of choice for the treatment of Wilson's disease, but recent experience suggests that trientine and zinc may be safe, effective alternatives. All three drugs are probably safe for use in pregnant patients with Wilson's disease. Liver transplantation is the only effective treatment for Wilsonian fulminant hepatic failure and corrects the underlying metabolic defect.

CONCLUSIONS

Wilson's disease is a disorder of hepatobiliary copper excretion manifested predominantly by hepatic and neurologic copper toxicosis and inherited in an autosomal recessive pattern. Although the specific underlying biochemical defect remains to be defined, specific therapy is available and usually successful. Maintaining a high index of suspicion is critical in diagnosing this readily treatable inherited disease.

Inhibition of copper-associated erythrocyte ghost membrane lipid peroxidation by hepatic cytosolic low molecular weight proteins

Male weanling Fischer rats were injected ip once daily with either 12.5 mg/kg body weight cupric chloride or 2 ml/kg body weight saline for up to 70 days. As the hepatic cytosolic copper increased in copper-treated rats, copper bound to proteins of different molecular weights; this was determined by gel filtration chromatography. Hepatic cytosolic copper from rats treated with cupric chloride for 14 days eluted in 3 peaks. These included a 150,000 + dalton peak, a 29,000 dalton peak and an 11,000-12,800 dalton peak. In addition to these peaks, hepatic cytosolic copper from rats treated with cupric chloride for greater than or equal to 28 days also eluted in a 4th, but shorter, 6,000-7,000 dalton peak. Hepatic cytosolic copper from saline-treated rats eluted only in a single 29,000 dalton peak. Experiments using an erythrocyte ghost membrane model of copper-associated lipid peroxidation demonstrated that incubation of membranes with protein-bound copper eluted in the 11,000-12,000 dalton peak was associated with less lipid peroxidation than incubation of membranes with cupric chloride or protein-bound copper eluted in the 150,000+ dalton peak. Experimental results suggest that the ability of copper to catalyze lipid peroxidation is significantly reduced by binding with hepatic cytosolic low molecular weight proteins but not by binding with hepatic cytosolic high molecular weight proteins.

Effects of copper on mammalian cell components

Both deficiency and excess of copper induce toxic effects on mammalian cell systems in vivo and in vitro. The effects can be related to the affinities of Cu(II) ions for specific cell components. The nucleus is a potential site for temporary Cu storage while primary targets for free Cu(II) ions are the thiol groups which reduce the ions to Cu(I). Cu(II) ions show a high affinity for nucleic acids, binding with DNA both at intrastrand and interstrand levels, possibly through intercalation between GC pairs. The ability to chelate Cu(II) ions is seen to be of the order: purine greater than purine ribonucleotides greater than purine ribonucleoside greater than pyrimidine ribonucleotides. Copper is an integral part of enzyme activation and enters into the molecular structure of several proteins, like ceruloplasmin. Cu(II) ion is a potential mutagenic agent as seen by its property of inducing infidelity in DNA synthesis in vitro. Teratogenic activities of copper have been reported but carcinogenicity is not yet confirmed. Copper is an essential component of chromatin and is known to accumulate preferentially in the heterochromatic regions. External application of higher doses, however, induces both clastogenic effects and spindle disturbances. In certain forms, inorganic copper enhances the clastogenic activity of other agents. The most widely studied human genetic maladies linked with copper metabolism are Menkes' and Wilson's diseases. Several mutations are known which influence Cu homeostasis in mammals. Such mutations in mice have been used extensively for biochemical studies.

Copper-induced hypercholesterolemia of golden hamsters: enhanced synthesis of cholesterol in the liver

Effects of a subtoxic dose of copper on cholesterol metabolism were studied in male golden hamsters. Intraperitoneal injections of cupric acetate increased serum levels of cholesterol and phospholipids without liver damage. This lipidemia was associated with increased cholesterol of the liver. The participation of hemolysis was denied by peripheral red blood cell tests. Hepatic microsomal 3-hydroxy-3-methyl-glutaryl-CoA reductase was also elevated by copper administration. Biliary secretion of cholesterol increased but that of bile acids remained unchanged, suggesting no impaired degradation of cholesterol. We conclude that hepatic synthesis of cholesterol is enhanced by a subtoxic dose of copper, resulting in hypercholesterolemia.

Mechanisms of hemolysis induced by copper

An excess of copper is the cause of hemolysis in a number of clinical conditions. Incubation of human erythrocyte (RBC) suspensions with copper (II) causes the formation of methemoglobin, lipid peroxidation and hemolysis. A new variant of the thiobarbituric acid (TBA) method, which minimizes the formation of interfering chromophores, was used to detect lipid peroxidation. Lipid peroxidation precedes hemolysis and the antioxidant vitamins C and E, which inhibit lipid peroxidation, also inhibit hemolysis. Consequently lipid peroxidation appears to be the cause of RBC destruction. Lipid peroxidation arises mostly from the oxidation of oxyhemoglobin by copper as it is inhibited in RBCs with carbon monoxyhemoglobin or methemoglobin. A direct interaction of copper with the red cell membrane seems to play only a minor role. Copper effects depend on the presence of free SH groups. Lipid peroxidation is probably initiated by activated forms of oxygen as it is increased by an inhibitor of catalase and reduced by hydroxyl radical scavengers. With higher copper concentrations hemolysis is greater: its mechanism appears different as lipid peroxidation is smaller but hemoglobin alterations, namely precipitation, are more pronounced.

The interaction of copper (Cu++) with the erythrocyte membrane and 2,3-dimercaptopropanesulphonate in vitro: a source of activated oxygen species

The therapy of copper poisoning and of Wilson's disease with 2,3-dimercaptopropane-1-sulphonate (DMPS) may increase the copper-induced haemolysis. Some aspects of the mechanism of this effect were investigated. The possible generation of activated oxygen species during the interaction of Cu++ and DMPS was studied using a chemiluminescent method detecting oxygen radicals. It was found that incubation of DMPS with copper ions (free or bond with erythrocyte membranes) is accompanied with generation of oxygen radicals. Activated oxygen species produced via O2- are able to increase the haemolytic effects of cupric salts. Hence DMPS treatment in cases of copper poisonings or Wilson's disease may involve risk of side effects on the basis of activated oxygen species generation.

Low serum alkaline phosphatase activity in Wilson's disease

Low values for serum alkaline phosphatase activity were observed early in the course of two patients with Wilson's disease presenting with the combination of severe liver disease and Coombs' negative acute hemolytic anemia. A review of other cases of Wilson's disease revealed that 11 of 12 patients presenting with hemolytic anemia had values for serum alkaline phosphatase less than their respective sex- and age-adjusted mean values; in eight, serum alkaline phosphatase activity was less than the lower value for the normal range of the test. Low values for serum alkaline phosphatase were much less common in Wilson's disease patients with more chronic forms of presentation. Copper added in high concentration to serum in vitro did not have an important effect on serum alkaline phosphatase activity. The mechanism responsible for the decrease in serum alkaline phosphatase activity in patients is uncertain.

Fulminant hepatic and renal failure complicating Wilson's disease

We report a case of fatal fulminant liver failure complicating Wilson's disease that is unique in several respects. The illness supervened after several years of medical noncompliance in a patient who had been previously diagnosed and successfully treated with penicillamine. Re-institution of penicillamine therapy 2 weeks prior to the fulminant decompensation failed to prevent it. Renal failure in this patient was apparently secondary to rhabdomyolysis. Addition of penicillamine to a peritoneal dialysis solution allowed chelation and removal of over 14 mg per day of copper but without apparent benefit. Exchange transfusion and high dose dexamethasone therapy (24 mg/day) were equally ineffective in reversing the liver failure. Other reported cases have also been fatal. The best treatment for fulminant Wilson's disease is prevention by diagnosis in a pre-symptomatic stage and institution of carefully supervised life-long therapy with penicillamine.

Haemolytic activity of copper as influenced by chelating agents, albumine and chromium

The haemolytic activity of CuSO4 (0.3 mM) in vitro was reduced in the presence of albumine (5-20 g/l). The presence of D-penicillamine, triethylene tetramine or dimercaptosuccinic acid (0.3 mM) also reduced the copper-induced haemolysis, whereas 2,3-dimercaptopropane-1-sulphonate increased the cytolysis. N-ethylmaleimide (NEM) in appropriate concentrations (1 mM), as well as chromic chloride (0.3 mM), reduced the copper-induced haemolysis. Higher concentrations of NEM (2 mM) were ineffective. The results may provide helpful suggestions as regarding the clinical treatment of copper poisoning and Wilson's disease. The results may also be helpful for the understanding of the mechanisms of haemolysis associated with copper intoxication in vivo.