Hepatic copper content is normal in early primary biliary cirrhosis and primary sclerosing cholangitis

Diagnostic Tests in Primary Sclerosing Cholangitis: Serology, Elastography, Imaging, and Histology

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by progressive inflammation and fibrosis of the biliary tree leading to biliary strictures, cholangitis, and cirrhosis. Early in presentation, patients may have normal liver tests, though over time develop a cholestatic pattern of liver injury. Diagnosis is made radiographically with magnetic resonance or endoscopic cholangiography. While several autoantibodies are associated with PSC, none have proven to have adequate diagnostic utility. Liver biopsy is rarely recommended unless to evaluate for small-duct PSC or overlap syndrome. Elastography, in various forms, is an effective, non-invasive modality to evaluate liver fibrosis in PSC.

Hepatic Dry Copper Weight in Pediatric Autoimmune Liver Disease

OBJECTIVES

Elevated hepatic dry copper weight is recognized in adults with autoimmune liver disease (AILD) and chronic cholestasis. We aim to review hepatic dry copper weight in pediatric AILD.

METHODS

Retrospective review of pediatric AILD managed at our institution from 1999 to 2018, and 104 patients with hepatic dry copper weight assessment were included.

RESULTS

Median age at presentation was 13.4 years (interquartile range, IQR, 11.7-14.9), 60% female, 54% autoimmune hepatitis, 42% autoimmune sclerosing cholangitis, and 4% primary sclerosing cholangitis. Histological features of advanced liver fibrosis in 68%. Median hepatic dry copper weight was 51.1 µg/g dry weight (IQR, 28.0-103.8). Elevated hepatic dry copper weight (>50 µg/g dry weight) was present in 51%, and was not associated with AILD subtype ( P = 0.83), age at presentation ( P = 0.68), or advanced fibrosis ( P = 0.53). Liver transplantation (LT) was performed in 10%, who had higher hepatic dry copper weight (148.5 µg/g dry weight [IQR, 39.5-257.3] vs 47.5 [IQR, 27.8-91.5], P = 0.04); however this was not associated with LT on multivariate analysis (hazard ratio 1.002, 95% CI 0.999-1.005, P = 0.23). In 8 (7.7%) patients ATP7B was sequenced and potentially disease causing variants were identified in 2 patients, both who required LT.

CONCLUSIONS

Elevations in hepatic dry copper weight are common in pediatric AILD. Unlike in adults, it is not associated with AILD subtypes with cholestasis. Higher dry copper weight was detected in patients who required LT. While further work is needed to identify the significance of copper deposition in pediatric AILD, we recommend close monitoring of patients with elevated levels for progressive liver disease.

Liver pathology in Wilson's disease: From copper overload to cirrhosis

Wilson's disease (WD) is a genetic metabolic disease strictly associated with liver cirrhosis. In this review, the genetic bases of the disease are discussed, with emphasis on the role of ATP7B (the Wilson disease protein) dysfunction as a determinant factor of systemic copper overload. Regarding the different multiple mutations described in WD patients, the peculiarity of Sardinian population is highlighted, Sardinians carrying a rare deletion in the promoter (5' UTR) of the WD gene. The role of epigenetic changes in the clinical presentation and evolution of liver disease in WD patients is also discussed, nutrition probably representing a relevantly risk factor in WD patients. The role of transmission electron microscopy in the diagnosis of WD-related liver disease is underlined. Mitochondrial changes, increased peroxisomes fat droplets, lipolysosomes and intranuclear glycogen inclusions are reported as the most frequent ultrastructural changes in the liver of WD carriers. The role of histochemical stains for copper is analyzed, and the Timm's method is suggested as the most sensitive one for revealing hepatic copper overload in all stage of WD. The marked variability of the histological liver changes occurring in WD is underlined simple steatosis may represent the only pathological changes, frequently associated with glycogenated nuclei. Mallory-Denk bodies lipogranulomas alcoholic and non-alcoholic fatty liver disease ending with bridging fibrosis and cirrhosis. Finally, the reversal of fibrosis as a possible therapeutic objective in WD is discussed.

Primary sclerosing cholangitis: diagnostic and management challenges

Primary sclerosing cholangitis (PSC) is a chronic immune-mediated disease affecting intra- and extrahepatic bile ducts, primarily the large biliary ducts. Clinical manifestations are broad, and the spectrum encompasses asymptomatic cholestasis, icteric cholangitis with pruritis, cirrhosis, and cholangiocarcinoma. Though rare, PSC has a propensity to affect young to middle-aged males and is strongly associated with inflammatory bowel disease. There is an unmet need for effective medical treatments for PSC, and to date, the only curative therapy is liver transplantation reserved for those with end-stage liver disease. This article addresses the diagnostic and management challenges of PSC, with a succinct analysis of existing therapies, their limitations, and a glimpse into the future of the management of this multifaceted pathologic entity.

Primary biliary cirrhosis: proposal for a new simple histological scoring system

BACKGROUND & AIMS

A simple and reproducible evaluation of non diagnostic histological lesions related to prognosis remains crucial in primary biliary cirrhosis (PBC). Presently there is no satisfactory simple scoring system analysing them reliably. We elaborated a semi-quantitative scoring system that assesses fibrosis, lymphocytic interface hepatitis (LIH) and ductopenia, separately. This study was aimed to evaluate its intra/interobserver reproducibility and its correlation with the main biochemical data.

METHODS

Liver biopsies from 33 consecutive newly diagnosed PBC patients were independently analysed by five liver pathologists. Fibrosis was classified into five stages (portal/periportal fibrosis/few septa/numerous septa/cirrhosis) and LIH into four grades. The bile duct ratio (BDR), i.e. ratio of the number of portal tracts with ducts to total number of portal tracts, Ludwig's and Scheuer's stages were evaluated. Intra and interobserver agreements were assessed. Histological results were correlated to the biochemical data.

RESULTS

Most patients had an early disease on clinical and biological parameters. The biopsies measured 23 mm on average (range 12 - 40 mm). Intraobserver reproducibility was substantial for fibrosis (κ = 0.68), LIH (κ = 0.69) and BDR (ICC = 0.69). Interobserver agreement for fibrosis was fair with the 5-class system (κ = 0.36), moderate with a 4-class system (κ = 0.56). moderate for LIH (κ = 0.59) and BDR (ICC = 0.50). Ludwig's and Scheuer's staging showed a fair interobserver agreement (κ = 0.32, κ = 0.31 respectively). Our system showed better correlations with biochemistry than Ludwig's and Scheuer's systems did.

CONCLUSIONS

This simple scoring system, assessing fibrosis, LIH and BDR separately, has a substantial intraobserver and a moderate interobserver reproducibility. Its prognostic relevance has to be evaluated.

Revisiting the topic of histochemically detectable copper in various liver diseases with special focus on venous outflow impairment

We surveyed histochemically detectable copper in various liver diseases with emphasis on chronic biliary disease (CBD) and venous outflow impairment. Using rhodanine, we graded copper accumulation in 298 liver specimens: venous outflow impairment (n = 64), CBD (n = 123), Wilson disease (WD) (n = 12), chronic hepatitis C (n = 32), steatohepatitis (n = 28), sarcoidosis (n = 15), cholestatic hepatitis (n = 12), and acute large bile duct obstruction (n = 12). Copper was detected in 39% of specimens; all had chronic liver disease. Copper increased with increasing fibrosis. CBD accumulated copper more frequently than other chronic diseases (except WD), both in early (61% vs 3%) and late (94% vs 59%) stages and in larger amounts. Rhodanine was positive in 73% of livers with CBD, 20% with sarcoidosis, 9% with chronic hepatitis C, and 7% with steatohepatitis. Copper was detected in 14% of chronic venous outflow impairment specimens; with 1 exception, stainable copper was absent in early stages but detected in 38% of cirrhotic livers. In conclusion, rhodanine helps differentiate CBD from other conditions, including venous outflow impairment; in the absence of advanced fibrosis, rhodanine positivity strongly favors CBD. In contrast, rhodanine positivity is nonspecific in cirrhosis, but the absence of copper in that setting excludes CBD.

Animal models of copper-associated liver disease

Recent advances in molecular biology have made possible the identification of genetic defects responsible for Wilson's disease, Indian childhood cirrhosis and copper toxicosis in Long Evans Cinnamon rats, toxic milk mice, and Bedlington terriers. The Wilson's disease gene is localized on human chromosome 13 and codes for ATP7B, a copper transporting P-type ATPase. A genetic defect similar to that of Wilson's disease occurs in Long Evans Cinnamon rats and toxic milk mice. Familial copper storage disorders in Bedlington and West Highland white terriers are associated with early subclinical disease, and copper accumulation with subsequent liver injury culminating in cirrhosis. The canine copper toxicosis locus in Bedlington terriers has been mapped to canine chromosome region CFA 10q26. Recently, a mutated MURR1 gene was discovered in Bedlington terriers affected with the disease. Idiopathic childhood cirrhosis is biochemically similar to copper toxicosis in Bedlington terriers, but clinically much more severe. Both conditions are characterized by the absence of neurologic damage and Kayser-Fleisher rings, and normal ceruloplasmin levels. A recent study added North Ronaldsay sheep to the list of promising animal models to study Indian childhood cirrhosis. Morphologic similarities between the two conditions include periportal to panlobular copper retention and liver changes varying from active hepatitis to panlobular pericellular fibrosis, and cirrhosis. Certain copper-associated disorders, such as chronic active hepatitis in Doberman pinschers and Skye terrier hepatitis are characterized by copper retention secondary to the underlying disease, thus resembling primary biliary cirrhosis in humans. Copper-associated liver disease has increasingly being recognized in Dalmatians. Copper-associated liver diseases in Dalmatians and Long Evans Cinnamom rats share many morphologic features. Fulminant hepatic failure in Dalmatians is characterized by high serum activities of alanine aminotransferase and aspartate aminotransferase, and severe necrosis of centrilobular areas (periacinar, zone 3) hepatocytes. Macrophages and surviving hepatocytes contain copper-positive material. Liver disease associated with periacinar copper accumulation has also been described in Siamese cats. Many questions regarding copper metabolism in mammals, genetic background, pathogenesis and treatment of copper-associated liver diseases remain to be answered. This review describes the similarities between the clinico-pathological features of spontaneous copper-associated diseases in humans and domestic animals.

Oxidative-phosphorylation defects in liver of patients with Wilson's disease

BACKGROUND

Wilson's disease (WD) is caused by mutations in a P-type ATPase and is associated with copper deposition in liver and brain. The WD protein is present in the trans-Golgi network and may also be imported into mitochondria. The WD protein functions as a P-type copper transporting ATPase in the Golgi but any action in mitochondria is at present unknown.

METHODS

We studied mitochondrial function and aconitase activity in WD liver tissue and compared the results with those in a series of healthy controls and patients without WD.

FINDINGS

There was evidence of severe mitochondrial dysfunction in the livers of patients with WD. Enzyme activities were decreased as follows: complex I by 62%, complex II+III by 52%, complex IV by 33%, and aconitase by 71%. These defects did not seem to be secondary to penicillamine use, cholestasis, or poor hepatocellular synthetic function.

INTERPRETATION

The results show that there is a defect of energy metabolism in WD. The pattern of enzyme defects suggests that free-radical formation and oxidative damage, probably mediated via mitochondrial copper accumulation, are important in WD pathogenesis. These results provide a rationale for a study of the use of antioxidants in WD.