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1.
Copper Depletion as a Therapeutic Strategy in Cancer.
Lopez, J, Ramchandani, D, Vahdat, L
Metal ions in life sciences. 2019
Abstract
Copper is an essential trace element that plays a critical role in a variety of basic biological functions, and serves as a key component in a number of copper-dependent enzymes that regulate such processes as cell proliferation, angiogenesis, and motility. A growing body of preclinical work has demonstrated that copper is essential to metastatic cancer progression, and may have a role in tumor growth, epithelial-mesenchymal transition, and the formation of the tumor microenvironment and pre-metastatic niche. As a result, copper depletion has emerged as a novel therapeutic strategy in the treatment of metastatic cancer. We present a review of the physiologic role of copper with a discussion of relevant enzymes of the copper proteome in both normal tissue and in cancer. We conducted a comprehensive review of the available preclinical data of several copper chelation agents, including penicillamine, trientine, disulfiram, clioquinol, and tetrathiomolybdate (TM), across a variety of tumor types. We also present the existing early phase clinical trial data for the use of the copper chelator TM in the treatment of breast cancer and other malignancies.
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2.
Heavy metal toxicity: An update of chelating therapeutic strategies.
Kim, JJ, Kim, YS, Kumar, V
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). 2019;:226-231
Abstract
AIM: This review illustrates heavy metals toxicity, currently available therapies and the role and efficacy of chelation therapy for its management. SUMMARY Heavy metals are necessary for various biological processes, but they become harmful in excess. Specifically, they induce oxidative stress by generating free radicals and reducing antioxidant levels. Heavy metals also alter the confirmation of protein and DNA and inhibit their function. Chelation therapy is commonly used to treat metals toxicity. Chelation is a chemical process that occurs when interaction between a central metal atom/ion and ligand leads to formation of a complex ring-like structure. The ligand has a donor ion/molecule, which has a lone pair of electrons and may be monodentate to polydentate. Each metal has a different reactivity with a ligand, so a specific chelation agent is required for each metal. Combination therapy with a chelating agent and an antioxidant led to improved outcome. CONCLUSION Heavy metal poisoning is a common health problem because of mining, smelting, industrial, agricultural and sewage waste. Heavy metals can be efficiently excreted from the body following treatment with proper chelation agents.
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3.
[Diagnosis and treatment of Wilson disease in Japan].
Shimizu, N
Rinsho shinkeigaku = Clinical neurology. 2019;(9):565-569
Abstract
Wilson disease is an autosomal recessive disorder based on inborn error of copper metabolism. The copper accumulates in the liver, brain, cornea, kidney, and other organs. This disease should be considered any individual with liver abnormality except infant, any patient older than teenage with neurological (especially for extra pyramidal signs) or neuropsychiatric disorder with or without liver disease and sibling of Wilson disease patient. Typically, a combination of low serum ceruloplasmine levels and high levels of urinary copper contents is sufficient to establish a diagnosis. As other diagnostic tests, measurement of hepatic copper content and ATP7B gene analysis are available. The key strategy of treatment is to reduce the amount of copper in the liver and other tissues by administering both copper-chelating agents, such as D-penicillamine or Trientine, and/or zinc acetate. The author recommend zinc acetate monotherapy for mild to moderate hepatic disorder, Trientine mono therapy for mild to moderate neurologic disorder and combination therapy of Trientine and zinc acetate for sever hepatic or neurologic disorder.
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4.
Formation and stability of the mixed-chelator complexes of Sr2+, Mg2+, Ca2+, Ba2+, and Y3+ in solution with bio-relevant chelators.
Begum, ZA, Rahman, IMM, Takase, T, Hasegawa, H
Journal of inorganic biochemistry. 2019;:141-148
Abstract
The formation and equilibria of Sr2+, Mg2+, Ca2+, Ba2+, and Y3+ (M) complexes with a mixed-chelator comprising two biodegradable chelators (GLDA, LG, 2-[bis(carboxymethyl)amino] pentanedioic acid; HIDS, LH, 2-(1,2-dicarboxyethylamino)-3-hydroxy-butanedioic acid) in an aqueous matrix was evaluated. The potentiometric measurement results (ionic strength, 0.10 M; temperature, 25 ± 0.1 °C) confirmed the formation of 1:1:1 (M:LG:LH) complexes and the experimental data sets were further used to derive the equilibrium constants for the ternary complexes. The [MHLGLH]5- complex was the dominant ternary complex with Sr2+, Mg2+, Ca2+, and Ba2+, while Y3+ formed [M(OH)2LGLH]7- as the principal ternary species. The trend in the overall formation constants of the MLmix (Lmix, LG:LH = 1:1) complexes was in the order: Y3+ > Ca2+ > Mg2+ > Sr2+ > Ba2+. The ternary complexation trend was interpreted using the corresponding atomic radii and solution-phase electronegativities of the elements. The modes of interaction between the chelators and cations in the MLmix systems were subsequently deduced, and evaluated by using Gaussian 16W program. The relative stabilities of the ternary complexes (ΔlogK) were interpreted by comparison with the stabilities of the corresponding binaries, with negative ΔlogK values observed for all the MLmix complexes.
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5.
Rebalancing metal dyshomeostasis for Alzheimer's disease therapy.
Yang, GJ, Liu, H, Ma, DL, Leung, CH
Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry. 2019;(8):1159-1170
Abstract
Alzheimer's disease (AD) is a type of neurodegenerative malady that is associated with the accumulation of amyloid plaques. Metal ions are critical for the development and upkeep of brain activity, but metal dyshomeostasis can contribute to the development of neurodegenerative diseases, including AD. This review highlights the association between metal dyshomeostasis and AD pathology, the feasibility of rebalancing metal homeostasis as a therapeutic strategy for AD, and a survey of current drugs that action via rebalancing metal homeostasis. Finally, we discuss the challenges that should be overcome by researchers in the future to enable the practical use of metal homeostasis rebalancing agents for clinical application.
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6.
Chelating Surfaces for Oriented Human Serum Albumin Molecules.
Tuccitto, N, Messina, GML, Li-Destri, G, Wietecka, A, Marletta, G
Langmuir : the ACS journal of surfaces and colloids. 2019;(9):3354-3362
Abstract
Protein immobilization in a specific conformation or orientation at an interface is influenced by specific interactions with the outer layer of the surface. A strategy to build-up a complex construct which is able to orient protein molecules, based on metal-cation chelation processes, is reported. The proposed methodology implies the formation of a mercaptoundecanoic acid monolayer on a gold surface that is activated to attach covalently the tripeptide glycyl-l-histidyl-l-lysine (GHK) on the surface, whose sites are then employed to chelate copper ions, providing a selective platform for the orientation of human serum albumin (HSA) molecules. The protein adsorption process on GHK and GHK-Cu(II)-complex surfaces was monitored by the in situ quartz crystal microbalance with dissipation monitoring (QCM-D) and force spectroscopy technique. The changes in frequency and dissipation factor as well as the D- f plots from QCM-D measurements help to characterize the changes in the protein conformation and are confirmed by force curve spectroscopy results. An improved kinetic model, based on random sequential adsorption with variable protein footprints, has been developed to predict and simulate the experimentally found HSA average surface coverage onto the GHK and GHK-Cu(II)-complex surfaces.
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7.
Acetyl-L-carnitine for patients with hepatic encephalopathy.
Martí-Carvajal, AJ, Gluud, C, Arevalo-Rodriguez, I, Martí-Amarista, CE
The Cochrane database of systematic reviews. 2019;(1):CD011451
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Abstract
BACKGROUND Hepatic encephalopathy is a common and devastating neuropsychiatric complication of acute liver failure or chronic liver disease. Ammonia content in the blood seems to play a role in the development of hepatic encephalopathy. Treatment for hepatic encephalopathy is complex. Acetyl-L-carnitine is a substance that may reduce ammonia toxicity. This review assessed the benefits and harms of acetyl-L-carnitine for patients with hepatic encephalopathy. OBJECTIVES To assess the benefits and harms of acetyl-L-carnitine for patients with hepatic encephalopathy. SEARCH METHODS We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, LILACS, and Science Citation Index Expanded for randomised clinical trials. We sought additional randomised clinical trials from the World Health Organization Clinical Trials Search Portal and ClinicalTrials.gov. We performed all electronic searches until 10 September 2018. We looked through the reference lists of retrieved publications and review articles, and we searched the FDA and EMA websites. SELECTION CRITERIA We searched for randomised clinical trials in any setting, recruiting people with hepatic encephalopathy. Trials were eligible for inclusion if they compared acetyl-L-carnitine plus standard care (e.g. antibiotics, lactulose) versus placebo or no acetyl-L-carnitine plus standard care. We are well aware that by selecting randomised clinical trials, we placed greater focus on potential benefits than on potential harms. DATA COLLECTION AND ANALYSIS We selected randomised clinical trials, assessed risk of bias in eight domains, and extracted data in a duplicate and independent fashion. We estimated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes. We measured statistical heterogeneity using I² and D² statistics. We subjected our analyses to fixed-effect and random-effects model meta-analyses. We assessed bias risk domains to control systematic errors. We assessed overall quality of the data for each individual outcome by using the GRADE approach. MAIN RESULTS We identified five randomised clinical trials involving 398 participants. All trials included only participants with cirrhosis as the underlying cause of hepatic encephalopathy. Trials included participants with covert or overt hepatic encephalopathy. All trials were conducted in Italy by a single team and assessed acetyl-L-carnitine compared with placebo. Oral intervention was the most frequent route of administration. All trials were at high risk of bias and were underpowered. None of the trials were sponsored by the pharmaceutical industry.None of the identified trials reported information on all-cause mortality, serious adverse events, or days of hospitalisation. Only one trial assessed quality of life using the Short Form (SF)-36 scale (67 participants; very low-quality evidence). The effects of acetyl-L-carnitine compared with placebo on general health at 90 days are uncertain (MD -6.20 points, 95% confidence interval (CI) -9.51 to -2.89). Results for additional domains of the SF-36 are also uncertain. One trial assessed fatigue using the Wessely and Powell test (121 participants; very low-quality evidence). The effects are uncertain in people with moderate-grade hepatic encephalopathy (mental fatigue: MD 0.40 points, 95% CI -0.21 to 1.01; physical fatigue: MD -0.20 points, 95% CI -0.92 to 0.52) and mild-grade hepatic encephalopathy (mental fatigue: -0.80 points, 95% CI -1.48 to -0.12; physical fatigue: 0.20 points, 95% CI -0.72 to 1.12). Meta-analysis showed a reduction in blood ammonium levels favouring acetyl-L-carnitine versus placebo (MD -13.06 mg/dL, 95% CI -17.24 to -8.99; 387 participants; 5 trials; very low-quality evidence). It is unclear whether acetyl-L-carnitine versus placebo increases the risk of non-serious adverse events (8/126 (6.34%) vs 3/120 (2.50%); RR 2.51, 95% CI 0.68 to 9.22; 2 trials; very low-quality evidence). Overall, adverse events data were poorly reported and harms may have been underestimated. AUTHORS' CONCLUSIONS This Cochrane systematic review analysed a heterogeneous group of five trials at high risk of bias and with high risk of random errors conducted by only one research team. We assessed acetyl-L-carnitine versus placebo in participants with cirrhosis with covert or overt hepatic encephalopathy. Hence, we have no data on the drug for hepatic encephalopathy in acute liver failure. We found no information about all-cause mortality, serious adverse events, or days of hospitalisation. We found no clear differences in effect between acetyl-L-carnitine and placebo regarding quality of life, fatigue, and non-serious adverse events. Acetyl-L-carnitine reduces blood ammonium levels compared with placebo. We rated all evidence as of very low quality due to pitfalls in design and execution, inconsistency, small sample sizes, and very few events. The harms profile for acetyl-L-carnitine is presently unclear. Accordingly, we need further randomised clinical trials to assess acetyl-L-carnitine versus placebo conducted according to the SPIRIT statements and reported according to the CONSORT statements.
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8.
Management of oxidative stress and other pathologies in Alzheimer's disease.
Simunkova, M, Alwasel, SH, Alhazza, IM, Jomova, K, Kollar, V, Rusko, M, Valko, M
Archives of toxicology. 2019;(9):2491-2513
Abstract
Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder, characterized by the formation, aggregation and accumulation of amyloid beta, perturbed metal (copper, iron and zinc) homeostasis, metal-induced oxidative stress, neuroinflammation, aberrant activity of acetylcholinesterase (AChE) and other pathologies. The aim of this review is to discuss the current therapies based on the "combination-drugs-multitargets" strategy to target multiple pathologies to block the progression of pathogenesis of AD. In addition to cholinergic and amyloid targets, a significant effort is focused on targeting the metal-induced oxidative stress component of the disease. The main focus of research is based on modifications of existing drugs with specific biological activity. Tacrine was the first AChE inhibitor to be introduced into clinical practice and has been frequently used for the design of multitarget-directed ligands. A number of hybrid compounds containing tacrine and structural moieties derived from natural sources such as flavonoids [quercetin, rutin, coumarin, gallamine, resveratrol, scutellarin, anisidine, hesperetin, (-)-epicatechin] and other molecules (melatonin, trolox) have also been applied to function as multitarget-directed ligands. Most of these hybrids are potent inhibitors of AChE and butyrylcholinesterase and also of amyloid-beta aggregation. In addition, the antioxidant functionality, represented by coumarins, melatonin and other antioxidant molecules reduces the level of oxidative stress via ROS-scavenging mechanisms, as well as via chelation of redox-active Cu and Fe, thus suppressing the formation of ROS via the Fenton reaction. Various medicinal plants are under investigation for their ability to ameliorate symptoms of AD. The therapeutic potency of huperzine A and B, ginseng, curcumin and other compounds is manifested predominantly by the inhibitory action toward AChE, antioxidant or radical-scavenging and redox metal-chelating activity, inhibition of amyloid-beta aggregation and tau-protein hyperphosphorylation and antiinflammatory activity. Flavonoids not only function as antioxidants and metal-chelating agents, but also interact with protein kinase and lipid kinase signaling pathways, and others involving mitogen-activated protein kinase, NF-kappaB and tyrosine kinase. Among the most promising group of substances with potential activity against AD are the flavonoids, including myricetin, morin, rutin, quercetin, fisetin, kaempferol, apigenin and glycitein, which have been shown, in vitro, to possess antiamyloidogenic and fibril-destabilization activity, as well as being able to act as metal chelators and to suppressing oxidative stress. In terms of the clinical use of multifunctional hybrids, herbal drugs or flavonoids against AD, some remaining challenges are to establish the ideal dose to develop effective formulations to preserve bioavailability and to determine the stage when they should be administered. If the onset of the disease could be delayed by a decade, the number of AD victims would be significantly reduced.
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9.
Randomized Crossover Trial of Phosphate-binding Medication on Serum Phosphate Levels in Patients With Aortic Stenosis.
Wald, DS, Chambers, J, Bestwick, JP, Wald, NJ
Clinical therapeutics. 2019;(10):2066-2072.e2
Abstract
PURPOSE Aortic stenosis is a common cause of valvular heart disease with no means of prevention. The recognized association between aortic stenosis and serum phosphate raises the possibility of preventing progression of the disorder by using phosphate-binding drugs, but there is uncertainty whether such treatment lowers serum phosphate levels in patients without diagnosed renal failure. This pilot study was conducted to answer this question in patients with aortic stenosis. METHODS A randomized, double-blind, crossover trial of the phosphate-binding drug sevelamer was conducted in 72 patients. Patients were prescribed sevelamer 0.8 g (low-dose), sevelamer 2.4 g (high-dose), and matching placebo, 3 times daily with food; each regimen lasted 6 weeks and was allocated at random. Serum phosphate levels were measured at the end of each treatment period, and within-person levels were compared. FINDINGS Sixty-one patients completed the 3 treatment periods. There was no significant difference in the mean end-treatment phosphate levels across all patients (3.38, 3.36, and 3.31 mg/dL with placebo, low-dose sevelamer, and high-dose sevelamer, respectively). Post hoc analysis showed a reduction in phosphate levels with increasing sevelamer dose in the highest baseline phosphate quartile group; a 0.3 mg/dL reduction (mean, 4.09 mg/dL with placebo, 3.95 mg/dL with low-dose sevelamer, and 3.79 mg/dL with high-dose sevelamer; Ptrend = 0.027). IMPLICATIONS Sevelamer had no overall statistically significant effect in lowering serum phosphate levels, but a reduction was observed in patients with phosphate levels in the highest quartile group of the population distribution. This hypothesis-generating result requires confirmation in an independent study. If confirmed, a trial of sevelamer in preventing the progression of aortic stenosis may be justified in patients with high phosphate levels. ISRCTN Registry identifier: ISRCTN17365679.
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10.
Successful Treatment of Single Infected Calciphylaxis Lesion With Intralesional Injection of Sodium Thiosulfate at High Concentration.
Zuhaili, B, Al-Talib, K
Wounds : a compendium of clinical research and practice. 2019;(8):E54-E57
Abstract
INTRODUCTION Calciphylaxis is a very complicated disease that usually presents in patients with end-stage renal disease (ESRD). Treatment for calciphylaxis is not well standardized and typically involves a multidisciplinary approach. One of the common medications used in calciphylaxis treatment is sodium thiosulfate (STS). However, its intravenous injection is associated with multiple side effects. CASE REPORT The authors present a case report of an intralesional injection of STS followed by a literature review of the common treatment modalities and possible further use of intralesional injections. A 51-year-old man with ESRD on peritoneal dialysis presented with a right calf biopsy-proven calciphylaxis lesion measuring 3.1 cm x 3.9 cm. About the same time, he had Pseudomonas-associated peritoneal catheter peritonitis. The calciphylaxis lesion was treated with bimonthly intralesional injections of STS. The lesion had a complete resolution by week 9. CONCLUSIONS The authors believe a higher local concentration of STS leading to a faster resolution and requiring less frequent injections needs to be further evaluated. Following additional studies, they also propose a greater use of intralesional STS injections in a select set of patients in the future.