tetrathiomolybdate and Body-Weight

Copper levels are elevated in a variety of liver fibrosis conditions. Lowering copper to a certain level protects against fibrosis. However, whether severe copper deficiency is protective against liver fibrosis is not known. The purpose of the present study is to evaluate this question by inducing severe copper deficiency using the copper chelator, tetrathiomolybdate (TM), in a bile duct ligation (BDL) rat model. Male Sprague-Dawley rats were divided into four groups: sham, sham plus TM, BDL, and BDL plus TM. TM was given in a daily dose of 10 mg/kg by body weight by means of intragastric gavage, beginning 5 days after BDL. All animals were killed 2 weeks after surgery. Severe copper deficiency was induced by TM overdose in either sham or BDL rats, as shown by decreased plasma ceruloplasmin activity. Liver injury and fibrosis were exacerbated in BDL rats with TM treatment, as illustrated by robustly increased plasma aspartate aminotransferase and hepatic collagen accumulation. Iron stores, as measured by plasma ferritin, were significantly increased in copper-deficient BDL rats. Moreover, hepatic heme oxygenase-1 expression was markedly down-regulated by copper deficiency in BDL rats. In addition, hepatic gene expression involving mitochondrial biogenesis and β-oxidation was significantly up-regulated in BDL rats, and this increase was abolished by copper deficiency. In summary, severe copper deficiency exacerbates BDL-induced liver injury and liver fibrosis, probably caused by increased iron overload and decreased antioxidant defenses and mitochondrial dysfunction.

Topics: Angiogenesis Inhibitors; Animals; Bile Ducts; Blotting, Western; Body Weight; Cholestasis; Copper; Glutathione; Heme Oxygenase-1; Immunohistochemistry; Iron; Ligation; Liver; Liver Cirrhosis; Lung Injury; Male; Molybdenum; Nutritional Status; Organ Size; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA; S-Adenosylmethionine

Tetrathiomolybdate (TM), a drug developed for the treatment of Wilson's disease, produces an antiangiogenic effect by reducing systemic copper levels. Several angiogenic cytokines appear to depend on normal levels of copper for activity. In both animal tumor models and in cancer patients, TM therapy has proved effective in inhibiting the growth of tumors. We have hypothesized that the activities of fibrotic and inflammatory cytokines are also subject to modulation by the availability of copper in a manner similar to angiogenic cytokines. As a first step in evaluating whether TM plays a therapeutic role in diseases of inflammation and fibrosis, we studied the effects of TM on a murine model of bleomycin-induced pulmonary fibrosis. Oral TM therapy resulted in dose-dependent reduction in serum ceruloplasmin, a surrogate marker of systemic copper levels. Significant decreases in systemic copper levels were associated with marked reduction in lung fibrosis as determined on the basis of histopathologic findings and a biochemical measure of fibrosis. The protection afforded by TM was also reflected in significantly reduced bleomycin-induced body-weight loss. In the next phase of this work, we will seek to determine the mechanisms by which TM brings about this therapeutic benefit.

Topics: Administration, Oral; Angiogenesis Inhibitors; Animals; Bleomycin; Body Weight; Ceruloplasmin; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Hydroxyproline; Lung; Mice; Mice, Inbred CBA; Molybdenum; Pulmonary Fibrosis

Long-Evans Cinnamon (LEC) rats were fed a diet containing 7 ppm Cu and 30 ppm Cu from 60 days after birth. Fischer (Fischer group) and LEC (LEC-control group) rats fed a 7 ppm Cu diet showed normal growth throughout the whole period (60 to 125 days after birth). On the other hand, LEC rats fed the 30 ppm Cu diet had decreased body weight and showed slight jaundice at around 100 days after birth. Tetrathiomolybdate (TTM, 10 mg/kg bw) was injected sub-cutaneously at 101 and 105 days after birth into half of the LEC rats fed the 30 ppm Cu diet. LEC rats given TTM (LEC+TTM group) recovered their body weight and the jaundice rapidly disappeared. However, LEC rats without TTM (LEC-TTM group) had sharply decreased body weight and showed severe jaundice at 103 days after birth. The hepatic Cu concentration in LEC+TTM rats (460 micrograms/g) exceeded that of LEC-control rats (330 micrograms/g) at 125 days after birth. Our data suggest that TTM is effective for treatment of acute hepatic injury in the LEC rat.

Topics: Animals; Bile; Body Weight; Chelating Agents; Copper; Disease Models, Animal; Hepatolenticular Degeneration; Jaundice; Liver; Male; Molybdenum; Rats; Rats, Inbred F344; Rats, Long-Evans; Tissue Distribution