Effect of glutathione depletion on removal of copper from LEC rat livers by tetrathiomolybdate

Tetrathiomolybdate (TTM) is a powerful and selective copper (Cu) chelator that is used as a therapeutic agent for Wilson disease. TTM is the sole agent that can remove Cu bound to metallothionein (MT) in the livers of Long-Evans rats with a cinnamon-like coat color (LEC rats). However, the administration of excess TTM causes the deposition of Cu and molybdenum (Mo) in the liver. In the present study, the effect of hepatic glutathione (GSH) depletion on the removal of Cu from the livers of LEC rats was evaluated to establish an effective therapy by TTM. Pretreatment with l-buthionine sulfoximine (BSO), a depletor of GSH in vivo, reduced the amounts of Cu and Mo excreted into both the bile and the bloodstream, and increased the amounts of Cu and Mo deposited in the livers of LEC rats in the form of an insoluble complex 4h after the TTM injection. The results suggest that GSH depletion creates an oxidative environment in the livers of LEC rats, and the oxidative environment facilitates the insolubilization of Cu and Mo in the livers of LEC rats after the TTM injection. Therefore, the effect of TTM on the removal of Cu from the liver was reduced in the oxidized condition. Wilson disease patients and LEC rats develop liver injury caused by oxidative damage. From a clinical viewpoint, increasing in the GSH concentration is expected to enhance the effect of TTM

Effect of glutathione depletion on removal of copper from LEC rat livers by tetrathiomolybdate

Tetrathiomolybdate (TTM) is a powerful and selective copper (Cu) chelator that is used as a therapeutic agent for Wilson disease. TTM is the sole agent that can remove Cu bound to metallothionein (MT) in the livers of Long-Evans rats with a cinnamon-like coat color (LEC rats). However, the administration of excess TTM causes the deposition of Cu and molybdenum (Mo) in the liver. In the present study, the effect of hepatic glutathione (GSH) depletion on the removal of Cu from the livers of LEC rats was evaluated to establish an effective therapy by TTM. Pretreatment with l-buthionine sulfoximine (BSO), a depletor of GSH in vivo, reduced the amounts of Cu and Mo excreted into both the bile and the bloodstream, and increased the amounts of Cu and Mo deposited in the livers of LEC rats in the form of an insoluble complex 4h after the TTM injection. The results suggest that GSH depletion creates an oxidative environment in the livers of LEC rats, and the oxidative environment facilitates the insolubilization of Cu and Mo in the livers of LEC rats after the TTM injection. Therefore, the effect of TTM on the removal of Cu from the liver was reduced in the oxidized condition. Wilson disease patients and LEC rats develop liver injury caused by oxidative damage. From a clinical viewpoint, increasing in the GSH concentration is expected to enhance the effect of TTM

Copper and zinc concentrations in the breast milk of mothers undergoing treatment for Wilson’s disease: a prospective study

Objective To evaluate the concentrations of copper and zinc in the breast milk of mothers undergoing treatment for Wilson’s disease (WD) and clarify whether they can safely breast feed their infants.Design This was an observational and prospective study in an individual-based case series.Setting Breast milk samples were collected from participants across Japan from 2007 to 2018 at the Department of Pediatrics, Teikyo University in Tokyo. This was a primary-care level study. Clinical data were collected from the participants’ physicians.Patients Eighteen Japanese mothers with WD who were treated with trientine, penicillamine or zinc, and 25 healthy mothers as controls, were enrolled.Main outcome measures Whey exacted from the milk was used to evaluate the distribution of copper by high-performance liquid chromatography-inductively coupled plasma mass spectrometry. Copper and zinc concentrations in the breast milk samples were analysed by atomic absorption spectrometry.Results Copper distribution was normal in the breast milk of mothers with WD treated with trientine, penicillamine or zinc. No peak was detected for trientine-bound or penicillamine-bound copper. The mean copper concentrations in the mature breast milk of patients treated with trientine, penicillamine and zinc were 29.6, 26 and 38 µg/dL, respectively, and were within the normal range compared with the value in healthy controls (33 µg/dL). Likewise, mean zinc concentrations were normal in the mature breast milk of patients treated with trientine and penicillamine (153 and 134 µg/dL, respectively vs 160 µg/dL in healthy controls). Zinc concentrations in the breast milk of mothers treated with zinc were significantly higher than those in control milk. All infants were born normally, breast fed by mothers undergoing treatment and exhibited normal development.Conclusions Our results suggest that mothers with WD can safely breast feed their infants, even if they are receiving treatment for WD

Arsenic (+3 oxidation state) methyltransferase is a specific but replaceable factor against arsenic toxicity

Inorganic metalloids, such as arsenic (As), antimony (Sb), selenium (Se), and tellurium (Te), are methylated in biota. In particular, As, Se, and Te are methylated and excreted in urine. The biomethylation is thought to be a means to detoxify the metalloids. The methylation of As is catalyzed by arsenic (+3 oxidation state) methyltransferase (AS3MT). However, it is still unclear whether AS3MT catalyzes the methylation of the other metalloids. It is also unclear whether other factors catalyze the As methylation instead of AS3MT. Recombinant human AS3MT (rhAS3MT) was prepared and used in the in vitro methylation of As, Se, and Te. As, but not Se and Te, was specifically methylated in the presence of rhAS3MT. Then, siRNA targeting AS3MT was introduced into human hepatocarcinoma (HepG2) cells. Although AS3MT protein expression was completely silenced by the gene knockdown, no increase in As toxicity was found in the HepG2 cells transfected with AS3MT-targeting siRNA. We conclude that AS3MT catalyzes the methylation of As and not other biomethylatable metalloids, such as Se and Te. We speculate that other methylation enzyme(s) also catalyze the methylation of As in HepG2 cells

Organochlorine and trace metal residues in adult southern bent-wing bat (Miniopterus schreibersii bassanii) in Southeastern Australia

In recent times, the apparent population decline of the southern bent-wing bat (Miniopterus schreibersii bassanii) at Bat Cave, Naracoorte has been ascribed to pesticide use in the region, following the finding of organochlorine and orgaonophosphate insecticide residues in bat guano. Adult southern bent-wing bats were collected from Bat Cave and Starlight Cave in 2003. Organochlorine contaminants were detected in all carcass samples: p,p&prime;-DDE was by far the most dominant contaminant with concentrations ranging from 11 000 to 59 000 ng g&minus;1, followed by p,p&prime;-DDT (110&ndash;1600 ng g&minus;1), p,p&prime;-DDD (35&ndash;620 ng g&minus;1), &sum;PCBs (33&ndash;490 ng g&minus;1), &sum;chlordane and related compounds (7.9&ndash;270 ng g&minus;1), HCB (1.6&ndash;120 ng g&minus;1), HP epox. (3.1&ndash;230 ng g&minus;1), TCPMOH (3.8&ndash;38 ng g&minus;1), &sum;HCHs (1.4&ndash;9.6 ng g&minus;1), and TCPMe (0.1&ndash;4.2 ng g&minus;1) (all values on lipid-weight basis). No significant difference in DDE, DDD, DDT, &sum;DDT, &sum;PCB, trans-chlordane, heptachlor epoxide, trans-nonachlor, &alpha;-HCH, &beta;-HCH, &gamma;-HCH, TCPMOH or TCPMe concentrations were observed either between sexes within sites, or between sites (p &gt; 0.05). However, there were significant differences in HCB and oxychlordane concentrations between sexes and between sites (p &lt; 0.05), between site differences in cis-nonachlor concentrations in male bats (p &lt; 0.05), and cis-chlordane concentrations between sexes at Starlight Cave, and between males of each site (p &lt; 0.05). There were also significant differences in the liver concentrations of some metals between sexes within sites (Ag, Cd, Co, Cu, Pb, Se, Zn), and between sites (Ag, Cd, Co, Cu, Hg, Pb, Se, V, Zn). Clustering or grouping of sites was observed when the OC data was expressed on a lipid-weight basis. These inter-site differences in OC concentrations reflect local exposure over a period of time, and do not unambiguously support any suggestion that we are witnessing incipient speciation. However, for conservation purposes, it may be prudent to assume that there are two sub-populations of M. s. bassani feeding in different locations in this region of southern Australia, rather than the single homogeneous population suggested by genetic studies.<br /

Concentration and subcellular distribution of trace elements in liver of small cetaceans incidentally caught along the Brazilian coast

Concentrations of trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, T-Hg, Org-Hg, Tl and Pb) were determined in liver samples of estuarine dolphin (Sotalia guianensis; n=20), Franciscana dolphin (Pontoporia blainvillei; n=23), Atlantic spotted dolphin (Stenella frontalis; n=2), common dolphin (Delphinus capensis; n=1) and striped dolphin (Stenella coeruleoalba; n=1) incidentally caught along the coast of São Paulo State and Paraná State, Brazil, from 1997 to 1999. The hepatic concentrations of trace elements in the Brazilian cetaceans were comparable to the data available in literature on marine mammals from Northern Hemisphere. Concentrations of V, Se, Mo, Cd, T-Hg and Org-Hg increased with increasing age in liver of both estuarine and Franciscana dolphins. Very high concentrations of Cu (range, 262-1970 μg/g dry wt.) and Zn (range, 242-369 μg/g dry wt.) were observed in liver of sucklings of estuarine dolphin. Hepatic concentrations of V, Se, T-Hg, Org-Hg and Pb were significantly higher in estuarine dolphin, whereas Franciscana dolphin showed higher concentrations of Mn, Co, As and Rb. Ratio of Org-Hg to T-Hg in liver was significantly higher in Franciscana dolphin than estuarine dolphin, suggesting that demethylation ability of methyl Hg might be lower in liver of Franciscana than estuarine dolphins. High hepatic concentrations of Ag were found in some specimens of Franciscana dolphin (maximum, 20 μg/g dry wt.), and 17% of Franciscana showed higher concentrations of Ag than Hg. These samples with high Ag concentration also exhibited elevated hepatic Se concentration, implying that Ag might be detoxified by Se in the liver. Higher correlation coefficient between (Hg+0.5 Ag) and Se than between Hg and Se and the large distribution of Ag in non-soluble fraction in nuclear and mitochondrial fraction of the liver also suggests that Ag might be detoxified by Se via formation of Ag2Se in the liver of Franciscana dolphin. © 2004 Elsevier Ltd. All rights reserved

Increased Urinary 3-Mercaptolactate Excretion and Enhanced Passive Systemic Anaphylaxis in Mice Lacking Mercaptopyruvate Sulfurtransferase, a Model of Mercaptolactate-Cysteine Disulfiduria

Mercaptopyruvate sulfurtransferase (Mpst) and its homolog thiosulfate sulfurtransferase (Tst = rhodanese) detoxify cyanide to thiocyanate. Mpst is attracting attention as one of the four endogenous hydrogen sulfide (H2S)/reactive sulfur species (RSS)-producing enzymes, along with cystathionine &beta;-synthase (Cbs), cystathionine &gamma;-lyase (Cth), and cysteinyl-tRNA synthetase 2 (Cars2). MPST deficiency was found in 1960s among rare hereditary mercaptolactate-cysteine disulfiduria patients. Mpst-knockout (KO) mice with enhanced liver Tst expression were recently generated as its model; however, the physiological roles/significances of Mpst remain largely unknown. Here we generated three independent germ lines of Mpst-KO mice by CRISPR/Cas9 technology, all of which maintained normal hepatic Tst expression/activity. Mpst/Cth-double knockout (DKO) mice were generated via crossbreeding with our previously generated Cth-KO mice. Mpst-KO mice were born at the expected frequency and developed normally like Cth-KO mice, but displayed increased urinary 3-mercaptolactate excretion and enhanced passive systemic anaphylactic responses when compared to wild-type or Cth-KO mice. Mpst/Cth-DKO mice were also born at the expected frequency and developed normally, but excreted slightly more 3-mercaptolactate in urine compared to Mpst-KO or Cth-KO mice. Our Mpst-KO, Cth-KO, and Mpst/Cth-DKO mice, unlike semi-lethal Cbs-KO mice and lethal Cars2-KO mice, are useful tools for analyzing the unknown physiological roles of endogenous H2S/RSS production