Copper protects against galactosamine-induced hepatitis

Aggravation of chemically-induced injury in perfused rat liver by extracellular ATP

The effects of purinergic receptor agonists on acute liver damage and hemodynamics were studied using chemically-induced liver injury. Rat livers were perfused in situ 24 h after treatment with D-galactosamine (800 mg/kg, i.p.). In these livers, infusion of ATP (50 microM) into the portal vein caused a rapid increase in the leakage of LDH and AST from perfused liver in a dose dependent manner, accompanied with flow reduction. The similar but less effective responses were also observed by the infusion of ADP. Infusion of adenosine, a P1-receptor agonist, induced only minimal changes of liver damage and flow rate. The ATP-induced changes were almost completely suppressed by P2-receptor antagonist, suramin, but not affected by P1-receptor antagonist, 8-phenyltheophylline. Pretreatment of rats with gadolinium chloride, which depletes Kupffer cells, did not inhibit the potentiation of liver damage caused by ATP, whereas hemodynamic effects of ATP were significantly attenuated by gadolinium. These results indicate that extracellular ATP aggravates acute liver injury mediated by P2-type purinergic receptors.

Synergistic liver toxicity of copper and retrorsine in the rat

To investigate the possible synergy between copper and retrorsine (a pyrrolizidine alkaloid) as a cause of Indian Childhood Cirrhosis, four groups of male Wistar rats were fed the following diets from weaning: A. Normal diet; B. Copper loaded (2 g CuSO4/kg diet); C. Retrorsine supplemented (Expt 1:25 mg/kg body weight/week by gavage, Expt 2:25 mg/kg food initially then 15 mg/kg food after 4 weeks); and D. Copper and retrorsine as above. Serial plasma samples were assayed for aminotransferases, albumin and bilirubin. Liver samples at biopsy and sacrifice provided samples for copper analysis and histology. Results showed that copper and retrorsine together significantly increased liver damage compared with feeding either alone as assessed by: 1. Increased mortality rate; 2. Decreased plasma albumin and increased plasma bilirubin (mainly conjugated) indicative of hepatocyte dysfunction; 3. Massive liver copper accumulation, and 4. Increased liver damage histologically. Thus retrorsine caused liver copper accumulation, and together copper and retrorsine led to severe hepatic dysfunction, characterised by hypoalbuminaemia and conjugated hyperbilirubinaemia. Plant alkaloids secreted in milk by grazing animals and copper from brass vessels may together produce Indian Childhood Cirrhosis.

Alpha-tocopherol deficiency fails to aggravate toxic liver injury but liver injury causes alpha-tocopherol retention

The possible aggravation of liver injury by impaired cellular antioxidant function was investigated. A vitamin E-deficient diet (0.5 mg/kg alpha-tocopherol; control 100 mg/kg) significantly reduced rat liver alpha-tocopherol concentrations after 4 weeks (1.8 +/- 1.7 micrograms/g; control 34.4 +/- 2.4 micrograms/g, p < 0.001). The effects of copper loading (Cu, 3 g/kg diet); galactosamine (GalN, 0.85 g/kg i.p.); or carbon tetrachloride (CCl4, 10 mmol/kg i.p.) were examined. Serum aspartate transaminase activity was elevated slightly by vitamin E deficiency but not by hepatic copper accumulation. In vitamin E-replete (E+) and vitamin E-deficient (E-) rats, GalN or CCl4 caused a large and comparable elevation in serum AST and OCT activity. This effect on AST was markedly reduced by copper loading in vitamin E replete (E+) rats, but in E(-) rats copper had significantly less protective effect. Copper also diminished the OCT response to GalN in E+, though not E-, rats. A significant rise in total hepatic alpha-tocopherol content followed administration of GalN or CCl4 in both normocupric and copper-laden E(-) rats. Thus alpha-tocopherol deficiency (a) was not hepatotoxic per se; (b) failed to potentiate the toxicity of copper, GalN or CCL4; but (c) partially abolished the protection by copper against toxin-induced liver injury. Retention of hepatic alpha-tocopherol after liver damage may partly explain low serum vitamin E levels seen in clinical liver disease.

The prevention of Indian childhood cirrhosis

Previous studies have led to the hypothesis that the gross hepatic copper storage characteristic of Indian childhood cirrhosis (ICC) is due to the early introduction of animal milk feeds which have been contaminated with copper from brass household utensils. Amongst the families of 100 cases of ICC, the incidence of ICC in children born after dietary advice had been given (1/86) was significantly lower than in older siblings (12/125). This study attempted to document the incidence of ICC and the usage of brass before and after an intervention programme in Pune District advising against this pattern of infant feeding. The study encountered numerous difficulties in data gathering, but documented a fall in ICC prevalence resulting in its virtual disappearance in Pune District. This contrasted with an unchanged incidence in Chandigarh. Although a fall in brass usage was seen in Pune District, this was actually a spontaneous sociological change rather than a result of health education.

Hypothesis: plant and fungal biocides, copper and Indian childhood liver disease

Hepatic copper accumulation is characteristic of Indian childhood cirrhosis (ICC) but in experimental animals causes only modest liver damage. Plant and fungal biocidal agents may be hepatotoxic, may increase hepatic copper concentration, and may be secreted in milk of lactating animals. Crotalaria species, Parthenium hysterophorus and Aspergillus flavus are possible contaminants of animal feeds in rural India, and we hypothesise that their products may be synergistic with copper in causing ICC.