Chelating polymeric beads as potential therapeutics for Wilson’s disease Jana Mattová a , Pavla Pouc ˇková a , Jan Kuc ˇka b , Michaela Škodová b , Miroslav Vetrík b , Petr Šte ˇpánek b , Petr Urbánek a , Miloš Petr ˇík c , Zbyne ˇk Novy ´ c , Martin Hruby ´ b,⇑ a Institute of Biophysics and Informatics, First Faculty of Medicine, Charles University in Prague, Salmovska 1, 120 00 Prague 2, Czech Republic b Institute of Macromolecular Chemistry AS CR, v.v.i., Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic c Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Hnevotinska 5, 77900 Olomouc, Czech Republic article info Article history: Received 23 December 2013 Received in revised form 1 May 2014 Accepted 3 May 2014 Available online 9 May 2014 Keywords: Wilson’s disease Polymer beads Chelators Copper chelation abstract Wilson’s disease is a genetic disorder caused by a malfunction of ATPase 7B that leads to high accumu- lation of copper in the organism and consequent toxic effects. We propose a gentle therapy to eliminate the excessive copper content with oral administration of insoluble non-resorbable polymer sorbents con- taining selective chelating groups for copper(II). Polymeric beads with the chelating agents triethylene- tetramine, N,N-di(2-pyridylmethyl)amine, and 8-hydroxyquinoline (8HQB) were investigated. In a preliminary copper uptake experiment, we found that 8HQB significantly reduced copper uptake (using copper-64 as a radiotracer) after oral administration in Wistar rats. Furthermore, we measured organ radioactivity in rats to demonstrate that 8HQB radiolabelled with iodine-125 is not absorbed from the gastrointestinal tract after oral administration. Non-resorbability and the blockade of copper uptake were also confirmed with small animal imaging (PET/CT) in mice. In a long-term experiment with Wistar rats fed a diet containing the polymers, we have found that there were no signs of polymer toxicity and the addition of polymers to the diet led to a significant reduction in the copper contents in the kidneys, brains, and livers of the rats. We have shown that polymers containing specific ligands could potentially be novel therapeutics for Wilson’s disease. Ó 2014 Elsevier B.V. All rights reserved. 1. Introduction Wilson’s disease is a genetic disorder of copper metabolism resulting in hepatic cirrhosis and basal ganglia degeneration (Ala et al., 2007; Butterworth, 2010). Inheritance is autosomal recessive, and the disease is caused by the malfunction of ATPase 7B (Bruha et al., 2010); more than 400 mutations of this gene have been described to date (Merle et al., 2007). Worldwide prevalence of this disease is 1:30,000 (Ala et al., 2007). The impaired function of the ATPase causes an inability to excrete copper into the bile, which is the main pathway for copper elimination in humans. This leads to high copper accumulation in the organism, especially in the liver and central nervous system. High concentrations of copper lead to numerous symptoms due to toxic oxidative-stress-related damage to the liver tissue, brain, and other parenchymal organs (Ala et al., 2007; Butterworth, 2010; Merle et al., 2007). The three typical clin- ical presentations are liver disease, neurological disease, and psy- chiatric disease (Ala et al., 2007; Bruha et al., 2010; Huster, 2010). Liver disease is the most common presentation, and in the later course of untreated Wilson’s disease, it may be fatal in all presenta- tions. Patients with liver disease typically develop all possible com- plications, including liver cirrhosis, portal hypertension, hepatic encephalopathy, and massive bleeding from esophageal varices (Ala et al., 2007;Uno et al., 1997). The currently recommended first-line therapy is based on low- ering copper concentrations in organs through the administration of copper-chelating agents (penicillamine, triethylenetetraam- mine, or tetrathiomolybdate) (Ala et al., 2007; Roberts and Schilsky, 2003), which leads to decreased uptake and increased elimination of copper into the urine. In addition, high doses of zinc salts are administered as a maintenance therapy because zinc blocks copper uptake from the gastrointestinal tract (Ala et al., 2007; Huster, 2010). Unfortunately, suitable zinc formulations are not available in all countries. The use of these drugs is limited by multiple and occa- sionally severe side effects, e.g., myelosupression, lupus, and myas- thenia for penicillamine (Huster, 2010; Das and Ray, 2006), which originate from the general recomplexation of essential elements within the body after uptake from the gastrointestinal tract. Signif- icant gastrointestinal disorders have been reported for zinc ther- apy (in fact, the doses applied cause mild zinc poisoning) http://dx.doi.org/10.1016/j.ejps.2014.05.002 0928-0987/Ó 2014 Elsevier B.V. All rights reserved. ⇑ Corresponding author. Tel.: +420 296809230. E-mail address: mhruby@centrum.cz (M. Hruby ´ ). European Journal of Pharmaceutical Sciences 62 (2014) 1–7 Contents lists available at ScienceDirect European Journal of Pharmaceutical Sciences journal homepage: www.elsevier.com/locate/ejps