Journal of Gastroenterology and Hepatology (1990) 5 , 420-424
LIVER AND BILIARY Liver copper concentration in Wilson’s disease: Effect of treatment with ‘anti-copper’ agents K. GIBBS AND J. M. WALSHE* Departments of Medicine and Psychiatry, University of Cambridge Clinical School, Cambridge, United Kingdom
Abstract Serial copper determinations have been made on the livers of 10 patients with Wilson’s disease. Two were studied before and eight after the start of treatment in order to assess the effect, if any, on the concentration of the metal. In two patients who were receiving no therapy and in one in whom it had been discontinued, the level of copper rose. In the latter patient, resumption of treatment then resulted in a fall in the level of copper in the liver. A similar fall was seen in seven patients on continuous therapy. In one patient, a very poor complier, there was a tendency for the liver copper concentration to rise over a 5-year period. All three therapies investigated - penicillamine, trientine and tetrathiomolybdate - when taken regularly, appear to be effective in reducing liver copper levels. Sixty-nine single determinations of liver copper have been plotted against time on treatment. This shows that the copper concentration falls rapidly in the first year. Thereafter, there is no linear relationship between the duration of treatment and liver copper. Poor compliers have a higher liver copper concentration than do good compliers. Determinations made from different portions of the liver showed that in only one of 19 examples was there an overlap between the near normal and the abnormal range. The principal mechanism of action of ‘anti-copper’ agents in Wilson’s disease appears to be the mobilization of copper from the tissues, but a secondary detoxifying action may come into play later.
Key words: liver copper, penicillamine, tetrathiomolybdate, trientine, Wilson’s disease, zinc.
INTRODUCTION Penicillamine was introduced for the treatment of Wilson’s disease in 1956, and it was then assumed that its mode of action was to mobilize copper from the tissues and promote its excretion in the urine.’ It soon became apparent that not only was the drug a highly effective but also, over the course of a few years, that it lowered the plasma copper and ceruloplasmin concentrations and it also reduced the copper load in the urine;4it also led to the disappearance of the Kayser Fleischer corneal rings.5 This latter observation
further supported the hypothesis that chelation therapy reduced the tissue concentration of copper. At a later date, a second copper-binding drug, trientine, was introduced for patients who had become penicillamine-intolerant and, like penicillamine, it also acted by mobilizing copper in the urine.6 No evidence has been adduced to suggest that either drug acts by promoting biliary excretion of the metal. Indeed, little copper is excreted via this route in patients with Wilson’s The first evidence that the liver copper concentration was reduced by treatment with penicillamine was published by Scheinberg and
*Statistical analysis by T. R. Dening. Correspondence: J. M. Walshe, Department of Neurology, Faculty of Clinical Sciences, School of Medicine, University College London, University Street, London, UK. Accepted for publication 2 January 1990.
42 1
Liver copper concentration in Wilson’s disease Sternlieb who showed, in five patients, that this was accompanied by an improvement in the histological p i ~ t u r e In . ~ a later series, Marecek and his colleagues made similar observations in 17 cases who had received long-term treatment with penicillamine.10 Two further reports by Scheinberg and Sternlieb have produced contradictory In the first of these, six patients showed a reduction of liver copper after 3-5 years of treatment. However, in their most recent report, a further seven patients, treated for up to 18 years, actually showed an increase of copper in the liver despite histological improvement. They concluded that ‘Penicillamineseems to be able to detoxify hepatic copper without significantly reducing the liver content of the element.’ It has not been our policy to perform routine serial liver biopsies but we have estimated the concentration of copper in the liver on a large number of cases over the past 30 years, including post-mortem tissue, surgical and needle biopsies and we now report our findings in the hope they will throw further light on this problem.
METHODS This series consists of 69 patients with Wilson’s disease seen at Addenbrooke’s Hospital over a period of 30 years in whom it has been thought necessary to perform a liver biopsy either for diagnosis or to assess the response to treatment, particularly when the patient has been thought to be a poor complier. The age range is 3-50 years. Ten patients were studied on more than one occasion. In two, the liver copper was estimated twice before the start of treatment while in eight there were sequential determinations while on maintenance therapy. In order to assess the accuracy of single needle biopsy cores, as representative of the distribution of copper in the whole organ, we studied more than one portion of tissu.e from post-mortem specimens and surgical biopsies on 19 occasions. Copper in the liver was estimated by wet washing the tissue with 1 m L of sulfuric and 1 mL of perchloric acid, neutralizing the reaction mixture with ammonia and forming a colour complex with diethyl dithiocarbamate; suitable standards were run on every occasion. The same method has been used throughout so that all results are strictly
comparable except for two pretreatment estimations made at referring hospitals.
RESULTS Determinations on separate portions of tissue were made on 19 occasions. The mean low value was 122.5 pg/g wet weight (range: 5.2-405.6 pg). The mean high value was 153.1 pg/g wet weight (range: 5.4-410.7 pg) giving a difference for the mean of 30.6 pg (1 pg/g wet weight is equal, approximately, to 5 Fg/g dry weight). A wide discrepancy was seen in three cases: in two both values were so high as to cause no diagnostic difficulties, in the first the variation was from 196.3 to 311.1 pg: in the second from 281.0 to 378.9 pg. The third patient was a poor complier who died of variceal haemorrhage, his values were 11.9 and 62.5 pg. This was the only example spanning the near normal to the abnormal range (upper limit of normal 10 pg/g wet weight, 50 pg/g dry weight). The evidence seems to suggest that single core biopsies will give a reasonably accurate assessment of the liver copper concentration. The results of serial determinations made on 10 patients are shown in Fig. 1. Two patients were studied twice before treatment, in each the first determination was made at the referring hospital. In both cases the period without therapy resulted in a significant rise in the liver copper. On the other hand, the three patients in whom the first
LIVER AND BILIARY Liver copper concentration in Wilson’s disease: Effect of treatment with ‘anti-copper’ agents K. GIBBS AND J. M. WALSHE* Departments of Medicine and Psychiatry, University of Cambridge Clinical School, Cambridge, United Kingdom
Abstract Serial copper determinations have been made on the livers of 10 patients with Wilson’s disease. Two were studied before and eight after the start of treatment in order to assess the effect, if any, on the concentration of the metal. In two patients who were receiving no therapy and in one in whom it had been discontinued, the level of copper rose. In the latter patient, resumption of treatment then resulted in a fall in the level of copper in the liver. A similar fall was seen in seven patients on continuous therapy. In one patient, a very poor complier, there was a tendency for the liver copper concentration to rise over a 5-year period. All three therapies investigated - penicillamine, trientine and tetrathiomolybdate - when taken regularly, appear to be effective in reducing liver copper levels. Sixty-nine single determinations of liver copper have been plotted against time on treatment. This shows that the copper concentration falls rapidly in the first year. Thereafter, there is no linear relationship between the duration of treatment and liver copper. Poor compliers have a higher liver copper concentration than do good compliers. Determinations made from different portions of the liver showed that in only one of 19 examples was there an overlap between the near normal and the abnormal range. The principal mechanism of action of ‘anti-copper’ agents in Wilson’s disease appears to be the mobilization of copper from the tissues, but a secondary detoxifying action may come into play later.
Key words: liver copper, penicillamine, tetrathiomolybdate, trientine, Wilson’s disease, zinc.
INTRODUCTION Penicillamine was introduced for the treatment of Wilson’s disease in 1956, and it was then assumed that its mode of action was to mobilize copper from the tissues and promote its excretion in the urine.’ It soon became apparent that not only was the drug a highly effective but also, over the course of a few years, that it lowered the plasma copper and ceruloplasmin concentrations and it also reduced the copper load in the urine;4it also led to the disappearance of the Kayser Fleischer corneal rings.5 This latter observation
further supported the hypothesis that chelation therapy reduced the tissue concentration of copper. At a later date, a second copper-binding drug, trientine, was introduced for patients who had become penicillamine-intolerant and, like penicillamine, it also acted by mobilizing copper in the urine.6 No evidence has been adduced to suggest that either drug acts by promoting biliary excretion of the metal. Indeed, little copper is excreted via this route in patients with Wilson’s The first evidence that the liver copper concentration was reduced by treatment with penicillamine was published by Scheinberg and
*Statistical analysis by T. R. Dening. Correspondence: J. M. Walshe, Department of Neurology, Faculty of Clinical Sciences, School of Medicine, University College London, University Street, London, UK. Accepted for publication 2 January 1990.
42 1
Liver copper concentration in Wilson’s disease Sternlieb who showed, in five patients, that this was accompanied by an improvement in the histological p i ~ t u r e In . ~ a later series, Marecek and his colleagues made similar observations in 17 cases who had received long-term treatment with penicillamine.10 Two further reports by Scheinberg and Sternlieb have produced contradictory In the first of these, six patients showed a reduction of liver copper after 3-5 years of treatment. However, in their most recent report, a further seven patients, treated for up to 18 years, actually showed an increase of copper in the liver despite histological improvement. They concluded that ‘Penicillamineseems to be able to detoxify hepatic copper without significantly reducing the liver content of the element.’ It has not been our policy to perform routine serial liver biopsies but we have estimated the concentration of copper in the liver on a large number of cases over the past 30 years, including post-mortem tissue, surgical and needle biopsies and we now report our findings in the hope they will throw further light on this problem.
METHODS This series consists of 69 patients with Wilson’s disease seen at Addenbrooke’s Hospital over a period of 30 years in whom it has been thought necessary to perform a liver biopsy either for diagnosis or to assess the response to treatment, particularly when the patient has been thought to be a poor complier. The age range is 3-50 years. Ten patients were studied on more than one occasion. In two, the liver copper was estimated twice before the start of treatment while in eight there were sequential determinations while on maintenance therapy. In order to assess the accuracy of single needle biopsy cores, as representative of the distribution of copper in the whole organ, we studied more than one portion of tissu.e from post-mortem specimens and surgical biopsies on 19 occasions. Copper in the liver was estimated by wet washing the tissue with 1 m L of sulfuric and 1 mL of perchloric acid, neutralizing the reaction mixture with ammonia and forming a colour complex with diethyl dithiocarbamate; suitable standards were run on every occasion. The same method has been used throughout so that all results are strictly
comparable except for two pretreatment estimations made at referring hospitals.
RESULTS Determinations on separate portions of tissue were made on 19 occasions. The mean low value was 122.5 pg/g wet weight (range: 5.2-405.6 pg). The mean high value was 153.1 pg/g wet weight (range: 5.4-410.7 pg) giving a difference for the mean of 30.6 pg (1 pg/g wet weight is equal, approximately, to 5 Fg/g dry weight). A wide discrepancy was seen in three cases: in two both values were so high as to cause no diagnostic difficulties, in the first the variation was from 196.3 to 311.1 pg: in the second from 281.0 to 378.9 pg. The third patient was a poor complier who died of variceal haemorrhage, his values were 11.9 and 62.5 pg. This was the only example spanning the near normal to the abnormal range (upper limit of normal 10 pg/g wet weight, 50 pg/g dry weight). The evidence seems to suggest that single core biopsies will give a reasonably accurate assessment of the liver copper concentration. The results of serial determinations made on 10 patients are shown in Fig. 1. Two patients were studied twice before treatment, in each the first determination was made at the referring hospital. In both cases the period without therapy resulted in a significant rise in the liver copper. On the other hand, the three patients in whom the first
