2501 McCubbin, et al: Tetrathiomolybdate treatment of arthritis Personal non-commercial use only. The Journal of Rheumatology Copyright © 2006. All rights reserved. Tetrathiomolybdate Is Effective in a Mouse Model of Arthritis MARK D. McCUBBIN, GUOQING HOU, GERALD D. ABRAMS, ROBERT DICK, ZHAN ZHANG, and GEORGE J. BREWER ABSTRACT. Objective. To test for protective effects of therapy with tetrathiomolybdate, a copper-lowering drug, against collagen-induced arthritis in mice. Methods. Mice were injected with bovine collagen II, and limb joint swelling and erythema were scored. Tetrathiomolybdate treated mice received drug by oral gavage or in drinking water. Plasma ceruloplasmin was followed as a measure of body copper status, and maintained between 20 and 60% of baseline. Urine for isoprostane studies was collected in metabolic cages. At sacrifice, blood was col- lected for cytokine assays, and hind limbs fixed in formalin. Results. Tetrathiomolybdate strongly protected against the collagen-induced arthritis as reflected in scores of swelling and erythema, and as seen histologically. Further, tetrathiomolybdate strongly pro- tected against the increase in urine isoprostanes (a marker of oxidant damage) seen in collagen treated controls. The drug also protected against the increase in interleukin 2, interleukin 1ß, and tumor necro- sis factor-α levels seen in collagen treated controls. Conclusion. Based on the positive results reported here, and the good safety profile of tetrathiomolyb- date in human studies so far, a trial of tetrathiomolybdate in arthritis syndromes seems warranted. (First Release Oct 15 2006; J Rheumatol 2006;33:2501–6) Key Indexing Terms: TETRATHIOMOLYBDATE COPPER ARTHRITIS INTERLEUKIN 2 TUMOR NECROSIS FACTOR-α INTERLEUKIN 1ß ISOPROSTANE From the Departments of Human Genetics, Pathology, and Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA. Supported in part by grants FD-R-002153 and FD-R-002132 from the US Food and Drug Administration and by miscellaneous gifts. The University of Michigan has recently licensed the antifibrotic and antiinflammatory uses of tetrathiomolybdate to Pipex Therapeutic Inc., Miami, FL. Dr. Brewer has equity in and is a paid consultant to Pipex Inc. M.D. McCubbin, BS, Research Assistant; G. Hou, PhD, Research Scholar; R. Dick, BS, Research Associate; Z. Zhang, PhD, Research Assistant, Department of Human Genetics; G.D. Abrams, PhD, Emeritus Professor, Department of Pathology; G.J. Brewer, MD, Emeritus Professor, Departments of Human Genetics and Internal Medicine, University of Michigan Medical School. Address reprint requests to Dr. G.J. Brewer, University of Michigan Medical School, 5024 Kresge Bldg. II, Ann Arbor, MI 48109-0534, USA. E-mail: brewergj@umich.edu Accepted for publication July 7, 2006. Tetrathiomolybdate (TM) is an anticopper drug under devel- opment for the initial treatment of Wilson’s disease 1 . The mechanism of action of TM involves forming a tripartite com- plex with copper and protein 2-5 . Given with food, TM binds food copper and endogenously secreted copper with protein in the alimentary tract, and prevents copper absorption. Given away from food, TM is well absorbed and complexes avail- able plasma copper (often called “free copper”) with plasma albumin and renders it unavailable for cellular uptake. This complex is primarily degraded in the liver with copper excre- tion in the bile 6 . Because of its fast action and low toxicity, TM is proving to be a very useful drug for the initial treatment of Wilson’s disease. Work over the past 2 decades has shown that lowering cop- per levels to a midrange has strong antiangiogenic effects 7-11 . We have subsequently shown that TM, through antiangio- genic properties, has excellent anticancer effects in preclinical models 12-18 . Clinical studies have also been encouraging and are ongoing 19,20 . The mechanism of action appears to be inhi- bition of multiple angiogenesis-promoting cytokines. Investigating inhibition of multiple cytokines by TM fur- ther, we postulated that TM would also inhibit key cytokines in the transforming growth factor-ß (TGF-ß) pathway, pro- ducing fibrosis in fibrotic diseases. To test this we studied the mouse models of bleomycin-induced pulmonary fibrosis 21,22 and carbon tetrachloride-induced cirrhosis 23 . Both studies showed TM to be strongly protective against development of fibrosis and organ injury, and documented inhibition of TGF-ß levels by TM. In other studies we showed TM protection against concanavalin A 23 and acetaminophen 24 liver injury in mice, and doxorubicin heart injury in mice 25 . In the course of these studies we showed that TM inhibited levels of the inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin 1ß (IL-1ß). Concanavalin A binds to liver cells, and because it is a T cell antigen, stimulates an immune attack on hepatocytes. Since TM therapy offers strong protection against liver injury in the concanavalin A model, we hypothesized that TM thera- py would also have efficacy in other immune-mediated dis- eases. We evaluated that hypothesis in the collagen-induced arthritis model. www.jrheum.org Downloaded on January 20, 2022 from