Journal Article•
Dimercaptosuccinic Acid (DMSA), A Non-Toxic, Water-Soluble Treatment For Heavy Metal Toxicity
01 Jun 1998-Alternative medicine review : a journal of clinical therapeutic (Altern Med Rev)-Vol. 3, Iss: 3, pp 199-207
TL;DR: DMSA is a sulfhydryl-containing, water-soluble, non-toxic, orally-administered metal chelator which has been in use as an antidote to heavy metal toxicity since the 1950s and is established as the premier metal chelation compound, based on oral dosing, urinary excretion, and its safety characteristics compared to other chelating substances.
Abstract: Heavy metals are, unfortunately, present in the air, water, and food supply. Cases of severe acute lead, mercury, arsenic, and cadmium poisoning are rare; however, when they do occur an effective, non-toxic treatment is essential. In addition, chronic, low-level exposure to lead in the soil and in residues of lead-based paint; to mercury in the atmosphere, in dental amalgams and in seafood; and to cadmium and arsenic in the environment and in cigarette smoke is much more common than acute exposure. Meso-2,3-dimercaptosuccinic acid (DMSA) is a sulfhydryl-containing, water-soluble, non-toxic, orally-administered metal chelator which has been in use as an antidote to heavy metal toxicity since the 1950s. More recent clinical use and research substantiates this compound’s efficacy and safety, and establishes it as the premier metal chelation compound, based on oral dosing, urinary excretion, and its safety characteristics compared to other chelating substances. (Altern Med Rev 1998;3(3):199-207)
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TL;DR: The results demonstrated that HgCl2 exposure significantly inhibited δ-aminolevulinate dehydratase (δ-ALA-D) activity in liver and only DMPS treatment prevented the inhibitory effect, indicating a lack of therapeutic effect of the antioxidants tested.
Abstract: Acute effects of mercury on mouse blood, kidneys, and liver were evaluated. Mice received a single dose of mercuric chloride (HgCl2, 4.6 mg/kg, subcutaneously) for three consecutive days. We investigated the possible beneficial effects of antioxidant therapy (N-acetylcysteine (NAC) and diphenyl diselenide (PhSe)2) compared with the sodium salt of 2,3-dimercapto-1-propanesulfonic acid (DMPS), an effective chelating agent in HgCl2 exposure in mice. We also verified whether metallothionein (MT) induction might be involved in a possible mechanism of protection against HgCl2 poisoning and whether different treatments would modify MT levels and other toxicological parameters. The results demonstrated that HgCl2 exposure significantly inhibited δ-aminolevulinate dehydratase (δ-ALA-D) activity in liver and only DMPS treatment prevented the inhibitory effect. Mercuric chloride caused an increase in renal non-protein thiol groups (NPSH) and none of the treatments modified renal NPSH levels. Urea concentration was increased after HgCl2 exposure. NAC plus (PhSe)2 was partially effective in protecting against the effects of mercury. DMPS and (PhSe)2 were effective in restoring the increment in urea concentration caused by mercury. Thiobarbituric acid-reactive substances (TBARS), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) activities and ascorbic acid levels were not modified after mercury exposure. Mercuric chloride poisoning caused an increase in hepatic and renal MT levels and antioxidant treatments did not modify this parameter. Our data indicated a lack of therapeutic effect of the antioxidants tested.
21 citations
01 Jan 2014
TL;DR: This chapter aims to show how this powerful combination of inherent magnetic phenomena and modified behaviour uniquely associated with the nanoscale can greatly benefit a number of environmental applications including groundwater remediation, wastewater treatment and environmental sensing, amongst others.
Abstract: The inherent properties of magnetic nanoparticles (MNPs) offer enormous benefits to many technologies which are focused on improving the quality of the environment in which we live. As reflected in this chapter, the majority of research to date incorporating MNPs for environmental applications has been in the treatment of water, whether in the remediation of groundwater or through the magnetic separation and/or sensing of contaminants present in various aqueous systems. MNPs couple the modified behaviour uniquely associated with the nanoscale, for example enhanced reactivities arising from enormous surface-to-volume ratios, with inherent magnetic phenomena such as superparamagnetism. As such, they offer precise selectivity and ultrahigh sensitivity in the detection, remediation and removal of micropollutants whilst functionalization further enables targeting of specific chemical and biological contaminants. This chapter aims to show how this powerful combination can greatly benefit a number of environmental applications including groundwater remediation, wastewater treatment and environmental sensing, amongst others. After an introduction and overview of the properties relevant to these environmental settings, the methods used to produce and functionalize MNPs are discussed. Various applications of MNPs are then considered, taking into account detrimental factors such as aggregation, deactivation and contaminant rerelease, before the chapter ends with a summary and discussion of future prospects.
20 citations
TL;DR: The amount of PpIX accumulated in skin under the present conditions was not large enough to produce any significant erythema after light exposure, and further studies are needed to evaluate the role of PPIX induced by iron chelators used, against photoaging and cancer prevention.
Abstract: Generation of the reactive oxygen species (ROS) in skin by exposure to ultraviolet (UV) radiation induces a number of cutaneous pathologies such as skin cancer, photosensitization, and photoaging among others. Skin iron catalyzes UV generation of ROS. Topical application of iron chelators reduces erythema, epidermal and dermal hypertrophy, wrinkle formation, tumour appearance. It has been proposed that iron chelators can be useful agents against damaging effects of both short- and long-term UV exposure. A better understanding of the action mechanisms of iron chelators, might be useful to developing effective anticancer and antiphotoaging cosmetic products. Iron chelators may lead to accumulation of protoporphyrin IX (PpIX), a strong photosensitizer. The action of iron chelators in skin, related to PpIX increase has not yet been thoroughly studied. Therefore, we have investigated the formation of PpIX in normal mouse skin after topical application of creams containing metal chelators. The amount and distribution of porphyrins formed was determined by means of non-invasive fluorescence spectroscopy. Deferoxamine (DF), ethylenediaminetetraacetic acid (EDTA), 1,2-diethyl-3-hydroxypyridin-4-one (CP94), but not meso-2,3-dimercaptosuccinic acid (DMSA), caused increased accumulation of endogenous porphyrins in the skin. Fluorescence excitation and emission spectroscopy confirmed that PpIX was the main fluorescent species. The amount of PpIX accumulated in skin under the present conditions was not large enough to produce any significant erythema after light exposure. Further studies are needed to evaluate the role of PpIX induced by iron chelators used, against photoaging and cancer prevention.
19 citations
TL;DR: Insight is given into natural antidotes for the management and prevention of HM toxicity and natural antioxidants are bestowed with scavenging and chelation properties and can be alternative for synthetic chelating agents.
Abstract: Toxicity due to heavy metals (HM), specifically mercury (Hg), arsenic (As), lead (Pb), and cadmium (Cd) remains a challenge to scientists till date. This review gives insights into natural antidotes for the management and prevention of HM toxicity. Various databases such as PubMed, Embase, and Science Direct were searched for available facts on natural antidotes and their commercial products against HM toxicity till date. Toxicity owing to such metals needs prevention rather than therapy. Natural antidotes, fruits and vegetables, rich in antioxidant are the answers to such toxicities. Synthetic chelators impart a major drawback of removing essential metals required for normal body function, along with the toxic one. Natural antioxidants are bestowed with scavenging and chelation properties and can be alternative for synthetic chelating agents. Natural compounds are abundantly available, economic, and have minimal side effects when compared with classical chelators. Prevention is better than cure and thus adding plentiful vegetables and fruits to our diet can combat HM toxicity-related illness. Graphical abstract.
18 citations
Cites background from "Dimercaptosuccinic Acid (DMSA), A N..."
...DMSA offers few of the key benefits, viz., oral route of administration, low toxicity, and resistance against redistributions of metals from organ to organ (Miller 1998)....
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..., oral route of administration, low toxicity, and resistance against redistributions of metals from organ to organ (Miller 1998)....
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TL;DR: The focus is then shifted to the findings on verbascoside, a phytochemical that exerts a strong anti-inflammatory activity against the development of experimental inflammatory bowel disease, and a comprehensive review of computational approaches to the discovery of phytochemicals for PPARα and PPARγ.
Abstract: Welcome to this special issue of PPAR Research on “Phytochemicals as modulators of PPARs and RXRs.” Plants have played a crucial role in the prevention and treatment of human diseases for thousands of years. A significant number of contemporary drugs with high efficacy are derived from herbal origin. These natural phytochemicals, including certain nutrients, are therefore of great medicinal value.
Peroxisome proliferator-activated receptors (PPARs) belong to the steroid hormone receptor superfamily that bind to and are activated by fatty acids, eicosanoids, and a group of xenobiotics called peroxisome proliferators. Each of these receptors binds to specific peroxisome proliferator response elements (PPRE) as a heterodimer with a retinoid X receptor (RXR). Binding to these receptors has been proven to control the pathological conditions associated with obesity, aging-related diseases, inflammation, immune disorder, cell cycle regulation as well as cancer. There is a strong mechanistic basis for PPAR and RXR targeting, as these nuclear receptors are transcriptional factors that modulate gene expression relevant to the control of blood glucose and lipids, as well as the processes of inflammation and carcinogenesis. Since PPARs play an important role in lipid metabolism, the search for natural ligands had begun with fatty acids and eicosanoids. In fact, the discovery that many natural dietary compounds, especially phytochemicals, are PPAR activators is of great significance for human health. With metabolic syndrome, diabetes, and chronic systemic inflammatory diseases now reaching pandemic proportions, the importance of the discovery of natural PPAR ligands is self-evident.
The special issue begins with a review of terpenoids as modulators of the PPAR family. To date more than 40,000 terpenoids have been described. Also known as isoprenoids, terpenoids constitute one of the largest and most diverse group of phytochemicals. Members of this phytochemical family are well known to us as the flavours of cinnamon, ginger, and cloves and the scents of camphor and eucalyptus. The vitamin A precursors known as carotenoids and psychoactive cannabinoids are also forms of terpenoid. In this issue, T. Goto and colleagues review the biosynthesis, metabolism, and plant origins of various dietary terpenoids. The physiological effects of these compounds on carbohydrate and lipid metabolism are described in terms of their PPARγ and PPARα activating abilities. This is followed by the research article on the kinetic assessment and therapeutic modulation of metabolic and obesity-associated inflammatory profiles by a high-fat diet, whereas the whole process was found to be mediated by PPAR activation. Another research article has proposed glycyrrhizic acid, the bioactive compound extracted from roots of licorice (Glycyrrhiza glabra), as a potent PPARγ agonist. This phytochemical is capable of ameliorating metabolic syndrome by affecting glucose homeostasis, lipid metabolism, and adipogenesis. The focus is then shifted to the findings on verbascoside, a phytochemical that exerts a strong anti-inflammatory activity against the development of experimental inflammatory bowel disease. This work by the S. Cuzzocrea team has proven that verbascoside is a PPARα ligand by using a knock-out animal model. S. N. Lewis and colleagues conclude this special issue with a comprehensive review of computational approaches to the discovery of phytochemical ligands for PPARα and PPARγ. This timely review is an excellent reference document for the existing 3D structures of PPAR receptors cocrystallized with a variety of ligands and available on-line at the RCSB database. Lewis gives an expert description of the potential for in silico screening of phytochemical databases. The challenges of applying computational techniques to the analysis of a flexible ligand binding to a flexible receptor are described. This review is a most helpful exposition of the state-of-the-art computational methods regarding natural PPAR ligand discovery.
Joshua K. Ko
Susanna S. Lee
Harry Martin
15 citations
References
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TL;DR: This article reviews the pharmacological properties and the uses of two important antidotes for heavy metal poisoning, DMSA and DMPS, water soluble chemical analogs of dimercaprol, which have less toxicity, greater water solubility, and lim ited lipid solubilities, and are effective when given orally.
Abstract: This article reviews the pharmacological properties and the uses of two important antidotes for heavy metal poisoning. Meso-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-l-propanesulfonic acid, Na salt (DMPS) are relatively new antidotes-new, that is, to the western world. Although DMSA was introduced originally by Friedheim et al (1) to increase uptake of antimony during schistosomiasis therapy, Liang et al (77) at Shanghai in 1957 were the first to report its effectiveness as an antidote for heavy metal poisoning. The synthesis and some of the metal binding properties of DMPS were reported in 1956 by Petrunkin from Kiev (3). Shortly thereaf ter, DMPS became an official drug in the Soviet Union, where it is known as Unithiol (4). Between 1956 and 1975, DMSA and DMPS were studied extensively, at both the basic science and clinical levels, in the People's Republic of China, the Soviet Union, and Japan. Some of these investigations have been cited and can be found in an earlier review (5). In the USA and western Europe, however, these two compounds received very little attention until recently. A paper by Friedheim & Corvi (6) in 1975, dealing with DMSA for the treatment of mercury poisoning, and the recent production and availability of DMPS from Heyl & Co., Berlin, stimulated investigators to "rediscover" and study these two metal-binding agents. DMSA and DMPS are water soluble chemical analogs of dimercaprol (British Anti-Lewisite, BAL). In contrast to BAL, they have less toxicity, greater water solubility, and lim ited lipid solubility, and are effective when given orally.
309 citations
"Dimercaptosuccinic Acid (DMSA), A N..." refers background in this paper
...DMSA has been shown in recent studies to be a safe and effective chelator of lead, reducing blood levels significantly.(1,34,35) At a dose of 10 mg/kg for five days in adult males, DMSA lowered blood lead levels 35....
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...DMSA was subsequently studied for twenty years in the People’s Republic of China, Japan, and Russia before scientists in Europe and the United States “discovered” the substance and its potential usefulness in the mid-1970s.(1) DMSA is a dithiol (containing two sulfhydryl, or S-H, groups) and an analogue of dimercaprol (BAL, British Anti-Lewisite), a lipid-soluble compound also used for metal chelation (see Figure 1)....
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TL;DR: It has been discovered that microtubules are destroyed by this form of mercury and this effect may explain the inhibition of cell division and cell migration, processes that occur only in the developmental stages, and other hypotheses will stimulate considerable experimental challenges in the future.
Abstract: The nervous system is the principal target for a number of metals. Inorganic compounds of aluminum, arsenic, lead, lithium, manganese, mercury, and thallium are well known for their neurological and behavioral effects in humans. The alkyl derivatives of certain metals--lead, mercury and tin--are specially neurotoxic. Concern over human exposure and in some cases, outbreaks of poisoning, have stimulated research into the toxic action of these metals. A number of interesting hypotheses have been proposed for the mechanism of lead toxicity on the nervous system. Lead is known to be a potent inhibitor of heme synthesis. A reduction in heme-containing enzymes could compromise energy metabolism. Lead may affect brain function by interference with neurotransmitters such as gamma-amino-isobutyric acid. There is mounting evidence that lead interferes with membrane transport and binding of calcium ions. Methylmercury produces focal damage to specific areas in the adult brain. One hypothesis proposes that certain cells are susceptible because they cannot repair the initial damage to the protein sythesis machinery. The developing nervous system is especially susceptible to damage by methylmercury. It has been discovered that microtubules are destroyed by this form of mercury and this effect may explain the inhibition of cell division and cell migration, processes that occur only in the developmental stages. These and other hypotheses will stimulate considerable experimental challenges in the future.
196 citations
"Dimercaptosuccinic Acid (DMSA), A N..." refers background in this paper
...Methyl mercury also easily crosses the blood-brain barrier and the placenta.(7) Inorganic and methyl mercury have a high affinity for sulfhydryls, reacting intracellularly with the sulfhydryl group on glutathione and cysteine, and histidine residues in proteins, and allowing transport out of the cell....
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...After lead is absorbed in the human body, it reacts with thiol (sulfhydryl) groups on peptides and proteins, inhibiting enzymes involved in heme synthesis and interfering with normal neurotransmitter functions.(7) This natural reaction with thiols is also the body’s method of eliminating lead, especially from the liver....
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TL;DR: Analysis of the data from the questionnaires indicated that little or no exogenous exposure to mercury occurred among the two groups.
Abstract: Mercury levels in blood and in mouth air before and after chewing were measured in 47 persons with ana 14 persons without dental amalgam restorations. Questionnaires relating to exogenous sources of mercury exposure were administered to both groups. Differences in the mouth air mercury levels before and after chewing were statistically significant in the group with amalgams, but not in the group without amalgams. Analysis of the data from the questionnaires indicated that little or no exogenous exposure to mercury occurred among the two groups. Blood mercury concentrations were positively correlated with the number and surface area of amalgam restorations and were significantly lower in the group without dental amalgams.
194 citations
TL;DR: Animal and human experiments demonstrate that the uptake, tissue distribution, and excretion of amalgam Hg is significant, and that dental amalgam is the major contributing source to Hg body burden in humans.
Abstract: For more than 160 years dentistry has used silver amalgam, which contains approximately 50% Hg metal, as the preferred tooth filling material. During the past decade medical research has demonstrated that this Hg is continuously released as vapor into mouth air; then it is inhaled, absorbed into body tissues, oxidized to ionic Hg, and finally covalently bound to cell proteins. Animal and human experiments demonstrate that the uptake, tissue distribution, and excretion of amalgam Hg is significant, and that dental amalgam is the major contributing source to Hg body burden in humans. Current research on the pathophysiological effects of amalgam Hg has focused upon the immune system, renal system, oral and intestinal bacteria, reproductive system, and the central nervous system. Research evidence does not support the notion of amalgam safety.
178 citations
TL;DR: Results suggest that lead-induced oxidative stress in vivo can be mitigated by pharmacologic interventions, which encompass both chelating as well as thiol-mediated antioxidant functions.
172 citations