A study on clinical pathological features and pathogenesis of liver fibrosis in children with Wilson’s disease / 解放军医学杂志

ABSTRACT

Objective To explore the clinical pathological features of Wilson's disease and the pathogenesis of liver fibrosis. Methods The clinical data and liver biopsy specimens obtained from 48 children with Wilson's disease were analysed. The pathological changes were studied with light microscopy, electron microscopy, combined with rhodanine and rubeanic acid for copper staining, Gordon-Sweet's staining for reticular fibers and Masson's staining for collagen fibers. Meanwhile, immunohistochemistry was used to investigate the expression of tissue inhibitors of metalloproteinase (TIMP) -1 and TIMP-2. The apoptosis of activated hepatic stellate cells (HSC) in liver tissues was illustrated with in situ end labeling (ISEL)(TUNEL POD method) and ?-SMA double staining. Results In all the cases, the mean onset age was 10.0?3.8 years, and the positive rates of family history, Kayser-Fleischer’s ring and decreased serum ceruloplasmin level were 29.2%, 68.8% and 93.0%, respectively. The levels of serum ALT, AST, ALP and ?-Glo were 3.6, 3.0, 2.7 and 2.0 fold of normal cutoff values. The major pathological changes in childhood patients with Wilson’s disease presented various chronic inflammatory changes in hepatic acini and portal tracts, interface hepatitis, focal or diffuse vesicular/ microvesicular steatosis, with large and irregular apoptotic bodies, Mallory's bodies, glycogenated nuclei, and eosinophilc granular hepatocytes. Among all the cases, 77.0% of liver specimens were positive for rhodanine and rubeanic acid staining for copper in hepatocyts, especially in the zone I of acinus. Ultrastructural observation showed swollen and unusual giant mitochondria, increased lysosomes and vesicular inclusions in hepatocytes. The incidence of hepatic fibrosis was 100%, presenting expanded portal tracts in the early, fibrotic septa in the moderate and cirrhosis in the late stage. The extent of TIMP-1 and TIMP-2 expression and number of activated HSC were increased in various degrees in all the liver specimens, while apoptotic HSCs were obviously decreased in the majority of cases. Conclusions The clinical and pathological changes of children with Wilson’s disease are varied and relatively obscure, and liver fibrosis appears early and progressive. Excessive activation and proliferation of HSC stimulated by liver injury and inflammation due to copper deposition and the decrease in activity of matrix degradation enzymes might be the important mechanisms underlying the occurrence and progression of hepatic fibrosis in Wilson's disease.