Reduction of erythrocyte catalase and superoxide dismutase activities in male inhabitants of a cadmium-polluted area in Jinzu river basin, Japan

Dimethylglycine Can Enhance the Cryopreservation of Red Blood Cells by Reducing Ice Formation and Oxidative Damage

The cryopreservation of red blood cells (RBCs) holds great potential for ensuring timely blood transfusions and maintaining an adequate RBC inventory. The conventional cryoprotectants (CPAs) have a lot of limitations, and there is an obvious need for novel, efficient, and biocompatible CPAs. Here, it is shown for the first time that the addition of dimethylglycine (DMG) improved the thawed RBC recovery from 11.55 ± 1.40% to 72.15 ± 1.22%. We found that DMG could reduce the mechanical damage by inhibiting ice formation and recrystallization during cryopreservation. DMG can also scavenge reactive oxygen species (ROS) and maintain endogenous antioxidant enzyme activities to decrease oxidative damage during cryopreservation. Furthermore, the properties of thawed RBCs were found to be similar to the fresh RBCs in the control. Finally, the technique for order performance by similarity to ideal solution (TOPSIS) was used to compare the performance of glycerol (Gly), hydroxyethyl starch (HES), and DMG in cryopreservation, and DMG exhibited the best efficiency. This work confirms the use of DMG as a novel CPA for cryopreservation of RBCs and may promote clinical transfusion therapy.

Plasma heavy metals and their effect on oxidative stress parameters of buffaloes inhabiting Buddha Nallah area of Ludhiana district in Punjab

In the present study, plasma lead, cadmium, arsenic and nickel concentrations and oxidative stress parameters in buffaloes residing near Buddha Nallah region were evaluated. Blood samples of 59 buffaloes were collected for the study and plasma was separated and analyzed for heavy metal levels and for oxidative stress parameters like reduced glutathione,malonyldialdehyde and superoxide dismutase. Significant increase in plasma heavy metal concentrations was recorded in the buffaloes of the region and significant decrease in GSH and SOD and significant increase in MDA levels were also recorded in the buffaloes of the region. Samples with higher levels of heavy metals depicted oxidative damage in the animals residing near Buddha Nallah area of the Ludhiana city.

Arsenic, Cadmium and Lead Erythrocyte Concentrations in Men with a High, Moderate and Low Level of Physical Training

The aim of the present study was to determine changes occurring in the erythrocyte concentrations of arsenic (As), cadmium (Cd) and lead (Pb) in highly trained males, moderately trained males and sedentary men living in the same area of Extremadura (Spain). Thirty sedentary subjects (24.34 ± 3.02 years) with no sports practice and a less active lifestyle formed the control group (CG). Twenty-four moderately trained subjects (23.53 ± 1.85 years), who practised sports at a moderate level between 4 and 7 h/week, without any performance objective and without following any type of systematic training, formed the group of subjects with a moderate degree of training (MTG). And 22 professional cyclists (23.29 ± 2.73 years) at the beginning of their sports season, who trained for more than 20 h/week formed the high-level training group (HTG). Erythrocyte samples from all subjects in a fasting stage were collected, washed and frozen at -80 °C until analysis. Erythrocyte analysis of the trace elements As, Cd and Pb was performed by inductively coupled plasma mass spectrometry (ICP-MS). As concentration was lower in CG (p < 0.01) and MTG (p < 0.01) than HTG. Cd (p < 0.001) and Pb (p < 0.05) concentrations were higher in CG than HTG. All results were expressed in μg/g Hb. Physical training produces a decrease in erythrocyte concentrations of Cd and Pb, as an adaptation in order to avoid their accumulation in the cells and preserve correct cellular functioning. The higher As concentration should be investigated in high-level sportsmen because of a possible negative effect on the cells.

Dietary Cadmium Chloride Supplementation Impairs Renal Function and Bone Metabolism of Laying Hens

This study was conducted to evaluate the toxic effects of cadmium (Cd) on the kidney function and bone development in laying hens. A total of 480 Hy-line laying hens aged 38 weeks were randomly allocated into five treatments, each of which included six replicates of 16 birds. The concentrations of Cd in the diets of the five groups were 0.47, 7.58, 15.56, 30.55, and 60.67 mg/kg. Results showed that serum calcium (Ca) levels decreased significantly in the 60.67 mg Cd/kg diet group (p < 0.05). The activities of serum alkaline phosphatase (ALP) and bone ALP (BALP) decreased significantly in the 15.56, 30.55 and 60.67 mg Cd/kg diet groups (p < 0.05). The levels of parathyroid hormone (PTH) increased significantly in the 30.55 and 60.67 mg Cd/kg diet groups, and the estradiol (E2), 1,25-(OH)2-D3 and calcitonin (CT) decreased significantly with the increase of dietary Cd supplementation (p < 0.05). Histological results presented enlargements of renal tubules and tubular fibrosis in the kidney and decreased trabecular bone in the tibia. Tartrate-resistant acidic phosphatase (TRAP) staining results of tibia showed that osteoclast was significantly increased at the relatively high dose of dietary Cd (p < 0.05). In addition, the renal function indicators of blood urea nitrogen (BUN), urea acid (UA), and creatinine were significantly increased in Cd supplemented groups compared with the control group (p < 0.05). Low dose Cd exposure induced antioxidant defenses accompanying the increase in activities of catalase (CAT), glutathione peroxidase (GSH-Px), and the levels of glutathione (GSH) in renal tissue. At the same time, with the increased Cd levels, the activities of CAT, GSH-Px decreased significantly, and the level of malondialdehyde (MDA) increased significantly (p < 0.05). The activities of Na+/K+-ATPase and Ca2+/Mg2+-ATPase decreased significantly in the relatively high levels of dietary Cd (p < 0.05). These results suggest that Cd can damage renal function and induce disorders in bone metabolism of laying hens.

The Diagnostic Role of Urinary N-Acetyl-β-D-glucosaminidase (NAG) Activity in the Detection of Renal Tubular Impairment

The kidney function can be assessed by a number of methods. The urinary excretion of enzymes, in particular N-acetyl-β-D-glucosaminidase (NAG), is considered a relatively simple, cheap, fast and non-invasive method in the detection and follow-up of renal tubular function under various conditions. The determination of urinary NAG provides a very sensitive and reliable indicator of renal damage, such as injury or dysfunction due to diabetes mellitus, nephrotic syndrome, inflammation, vesicoureteral reflux, urinary tract infection, hypercalciuria, urolithiasis, nephrocalcinosis, perinatal asphyxia, hypoxia, hypertension, heavy metals poisoning, treatment with aminoglycosides, valproate, or other nephrotoxic drugs. This paper gives an overview of the current use of urinary NAG in the detection of renal injury.

The biochemical effects of occupational exposure to lead and cadmium on markers of oxidative stress and antioxidant enzymes activity in the blood of glazers in tile industry

The aim of the present study was to evaluate the effects of occupational exposure to lead (Pb) and cadmium (Cd) on markers of oxidative stress in glazers in tile industries. Total antioxidant capacity (TAC), malondialdehyde (MDA), and the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were determined in the blood of 80 subjects, including 40 glazers and 40 nonexposed subjects. Mean levels of blood Cd (8.90 ± 2.80 µg/L) and blood Pb (62.90 ± 38.10 µg/L) of glazers showed a significant increase compared with the control group. In the serum of glazers, the level of MDA was significantly higher and the level of TAC was significantly lower than the control group. We have noted a disturbance in the levels of antioxidants by a significant increase in the CAT activity and a significant decrease in the activities of SOD and GPx in the serum of glazers compared with the controls. Correlation analysis demonstrated that the serum MDA level and CAT activity were positively associated with the blood levels of Pb and Cd. Also, GPx and SOD were negatively correlated with blood Cd levels. The study clearly indicated that co-exposure to Cd and Pb can induce oxidative stress in glazers, resulting in increased lipid peroxidation and altered antioxidant enzymes.

Remarkable differences in the biochemical fate of Cd2+, Hg2+, CH3Hg+ and thimerosal in red blood cell lysate

The application of a metallomics method revealed that all investigated Hg species bound to hemoglobin and that these interactions are of toxicological significance.

Protective effect of Irvingia gabonensis stem bark extract on cadmium-induced nephrotoxicity in rats

Cadmium has been considered a risk factor for humans as it accumulates in body tissues, such as the liver, lungs, kidneys, bones, and reproductive organs. The aim of the present study was to evaluate the effect of Irvingia gabonensis (IG) against cadmium (Cd)-induced nephrotoxicity. The study was performed on twenty (20) male rats divided into four groups: control group, cadmium group (4 mg/kg/day, intraperitoneally), cadmium + extract (200 mg/kg body weight by oral gavage) and cadmium + extract (400 mg/kg body weight by oral gavage). Changes in the kidney biochemical markers, namely glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), aminotransferase (ALT), aspartate aminotransferase (AST) activities and levels of malondialdehyde (MDA), urea, and creatinine were determined in serum. Histological examinations were monitored. Exposure to Cd lowered the activities of kidney antioxidants, while it increased LPO levels. Levels of all disrupted parameters were alleviated by co-administration of IG extract. The malondialdehyde concentration of the rats treated with 200 and 400 mg/kg body weight of the extract significantly decreased (p<0.05) compared with the untreated cadmium rats. Yet the creatinine concentration decreased significantly (p<0.05) when the cadmium animals treated with 200 and 400 mg/kg body weight of the extract were compared with the cadmium control. Furthermore, histological alterations in the kidney were observed in cadmium untreated rats and these were ameliorated in cadmium treated rats by co-administration of IG extract. IG showed apparent protective and curative effect on Cd-induced nephrotoxicity.

Prophylactic Effects of Ethanolic Extract of Irvingia gabonensis Stem Bark against Cadmium-Induced Toxicity in Albino Rats

The prophylactic effect of ethanolic extract of Irvingia gabonensis stem bark on cadmium-induced oxidative damage in male albino rats’ liver was investigated. Male Wistar rats were divided into control, cadmium, and treatment groups. In the prophylactic experiment, Irvingia gabonensis (200 and 400 mg/kg body weight) was administered by oral gavage for 21 days before exposure to cadmium. Antioxidant marker enzymes such as reduced glutathione (GSH) levels, catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and lipid peroxidation (LPO) were determined in the liver and heart alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were monitored and histological examination was carried out. Results indicate that cadmium-induced rats had significantly increased relative weight of liver and heart when compared to controls. Treatment with Irvingia gabonensis at 200 and 400 mg/kg caused a significant decrease in relative weight of the organs. In cadmium-induced rats, serum ALT and AST activities and levels of LPO were increased whereas hepatic and cardiac marker enzymes significantly decreased. Furthermore, histological alteration in liver and aorta was observed in cadmium untreated rats and was ameliorated in cadmium rats treated with Irvingia gabonensis. In conclusion, the extract indicates antioxidant and hepatoprotective properties that eliminate the deleterious effects of toxic metabolites of cadmium.

Do toxic heavy metals affect antioxidant defense mechanisms in humans?

The aim of this study was to prove whether anthropogenic pollution affects antioxidant defense mechanisms such as superoxide dismutase (SOD) and catalase (CAT) activity, ferritin (FRT) concentration and total antioxidant status (TAS) in human serum. The study area involves polluted and salted environment (Kujawy region; northern-middle Poland) and Tuchola Forestry (unpolluted control area). We investigated 79 blood samples of volunteers from polluted area and 82 from the control in 2008 and 2009. Lead, cadmium and iron concentrations were measured in whole blood by the ICP-MS method. SOD and CAT activities were measured in serum using SOD and CAT Assay Kits by the standardized colorimetric method. Serum TAS was measured spectrophotometrically by the modified Benzie and Strain (1996) method and FRT concentration-by the immunonefelometric method. Pb and Cd levels and SOD activity were higher in volunteers from polluted area as compared with those from the control (0.0236 mg l(-1) vs. 0.014 mg l(-1); 0.0008 mg l(-1) vs. 0.0005 mg l(-1); 0.137 Um l(-1) vs. 0.055 Um l(-1), respectively). Fe level, CAT activity and TAS were lower in serum of volunteers from polluted area (0.442 g l(-1) vs. 0.476 gl(-1); 3.336 nmol min(-1)ml(-1) vs. 6.017 nmol min(-1)ml(-1); 0.731 Trolox-equivalents vs. 0.936 Trolox-equivalents, respectively), whilst differences in FRT concentration were not significant (66.109 μg l(-1) vs. 37.667 μg l(-1), p=0.3972). Positive correlations between Pb (r=0.206), Cd (r=0.602) and SOD in the inhabitants of polluted area, and between Cd and SOD in the control (r=0.639) were shown. In volunteers from both studied environments TAS-FRT (polluted: r=0.625 vs. control: r=0.837) and Fe-FRT (polluted area: r=0.831 vs. control: r=0.407) correlations, and Pb-FRT (r=0.360) and Pb-TAS (r=0.283) in the control were stated. The higher lead and cadmium concentrations in blood cause an increase of SOD activity. It suggests that this is one of the defense mechanisms of an organism against oxidative stress caused by environmental factors, whilst non-enzymatic mechanisms marked by TAS are the main antioxidant defense system in relation with Pb concentration in humans from unpolluted area. Simultaneously, the higher CAT activity and TAS can indicate that these mechanisms play a key role in the antioxidant protection in non-stressed environments.

The late and persistent pathogenic effects of cadmium at very low levels on the kidney of rats

Cadmium (Cd) is an important nephrotoxic pollutant. To examine late effects on the kidney of individuals previously exposed to chronic Cd at very low levels, male Wistar rats were given 20 nmol/kg i.p. injections of Cd every other day for 4 weeks. At the 20(th), 28(th), 36(th), 44(th) and 52(nd) week of the study, renal metal accumulation, morphology and function were examined. Immunochemical staining was performed to detect renal 3-nitrotyrosine (3-NT) accumulation, metallothionein (MT) expression, cell proliferation and global DNA methylation. Results showed that renal Cd concentration and MT expression along with 3-NT accumulation were significantly higher in the Cd group than that in the control. Histopathologically renal tubule damage at the early stage and hyperplasia at the late stage were observed in the Cd group. Renal fibrosis in glomeruli was evident in the Cd group, particularly at the late stage of the study. Immunoreactivity of global DNA methylation was markedly diminished in the Cd group at both 20(th) and 52(nd) weeks. These results suggest that previous exposure to chronic Cd at very low level induced persistent damaging effects on the kidney along with increases in cell proliferation and global DNA hypomethylation.

Interrelationships between cadmium, zinc and antioxidants in the liver of the rat exposed orally to relatively high doses of cadmium and zinc

Zinc (Zn) reduces cadmium (Cd)-induced toxicity in the liver although it increases Cd tissue burden in some conditions; hence, the present study is designed to study the relationships between Cd, Zn and antioxidants in the liver of rats exposed to Cd. Livers of male rats which received orally relatively high doses of Cd (200 mg Cd/L as Cd chloride or Cd (200 mg/L)+Zn (500 mg Zn as Zn chloride) during five weeks, were investigated. Cd induced an accumulation of Cd and Zn in parallel to depletion in important variables (GSH, GSH/GSSG, CuZn-SOD and GPx activities) and to elevation in others (Cd/Zn and GSSG). Cd, did not affect CuZn SOD/GPx, nor Mn-SOD in the liver. Cd accumulation, Cd/Zn, CuZn SOD activity and CuZn SOD/GPx, was increased remarkably under Zn action. Zn supply ameliorated GSH level and partially reversed the decrease in GSH/GSSG, but it did not ameliorate GPx activity. Analysis showed high correlations between Cd and the majority of the variables, while Zn was positively correlated with only GSSG. We suggest from our results that Zn has indirect ameliorative effects on Cd-induced toxicity in the liver and that the increase in Cd retention is probably the key mechanism modulating, in the case of relatively high doses of Cd, the antioxidant response during exposure to Cd and Zn.

Metallothionein gene expression in liver of rats exposed to cadmium and supplemented with zinc and selenium

Cadmium (Cd), one of the most widely distributed heavy metals, is highly toxic to humans and animals. It is well known that zinc (Zn) and selenium (Se) administration reduce the Cd-induced toxicity and that metallothioneins can have a protective effect to mitigate Cd toxicity in biological systems. In this study we report the expression analysis of the two metallothioneines gene classes MT-1 and MT-2 as well as the total metalloprotein content in the liver of rats exposed to Cd (200 ppm), Cd + Zn (200 ppm + 500 ppm), Cd + Se (200 ppm + 0.1 ppm) or Cd + Zn + Se (200 ppm + 500 ppm + 0.1 ppm) in their drinking water for 35 days. Metals accumulation was quantified in rat liver. Cd decreased significantly the hepatic concentrations of Se and increased those of Zn. The treatment of Cd-exposed rats with Se alone or combined with Zn reversed the Cd-induced depletion of Se concentrations in the liver. However, Zn or Zn + Se administration significantly increased the liver Cd uptake and had no effect on the Cd-induced increase in hepatic concentrations of Zn. The molecular assay showed a decreasing trend of MT-1 relative gene expression levels in animals supplemented with Zn (6.87-fold), Se (3.58-fold), and their combination (1.69-fold) when compared to Cd-treated animals (16.22-fold). Upregulation of the MT-2 expression were recorded in all conditions, although fold induction levels were less pronounced than MT-1 expressions. Our data suggest that the well-established protective effect of Zn and Se against Cd-induced toxicity passes through non-MT gene expression mechanisms, being more dependent on the oxidative stress status of the cell.

Factors influencing intestinal cadmium uptake in pregnant Bangladeshi women--a prospective cohort study

Experimental studies indicate that zinc (Zn) and calcium (Ca) status, in addition to iron (Fe) status, affect gastrointestinal absorption of cadmium (Cd), an environmental pollutant that is toxic to kidneys, bone and endocrine systems. The aim of this study was to evaluate how various nutritional factors influence the uptake of Cd in women, particularly during pregnancy. The study was carried out in a rural area of Bangladesh, where malnutrition is prevalent and exposure to Cd via food appears elevated. The uptake of Cd was evaluated by associations between erythrocyte Cd concentrations (Ery-Cd), a marker of ongoing Cd exposure, and concentrations of nutritional markers. Blood samples, collected in early pregnancy and 6 months postpartum, were analyzed by inductively coupled plasma mass spectrometry (ICPMS). Ery-Cd varied considerably (range: 0.31-5.4microg/kg) with a median of 1.1microg/kg (approximately 0.5microg/L in whole blood) in early pregnancy. Ery-Cd was associated with erythrocyte manganese (Ery-Mn; positively), plasma ferritin (p-Ft; negatively), and erythrocyte Ca (Ery-Ca; negatively) in decreasing order, indicating common transporters for Cd, Fe and Mn. There was no evidence of Cd uptake via Zn transporters, but the association between Ery-Cd and p-Ft seemed to be dependent on adequate Zn status. On average, Ery-Cd increased significantly by 0.2microg/kg from early pregnancy to 6 months postpartum, apparently due to up-regulated divalent metal transporter 1 (DMT1). In conclusion, intestinal uptake of Cd appears to be influenced either directly or indirectly by several micronutrients, in particular Fe, Mn and Zn. The negative association with Ca may suggest that Cd inhibits the transport of Ca to blood.

Protective effects of selenium (Se) and zinc (Zn) on cadmium (Cd) toxicity in the liver of the rat: effects on the oxidative stress

Cadmium (Cd) is a very harmful environmental pollutant that transfers between various levels of the food chain. To study the protective effect of Se and Zn on Cd-induced oxidative stress in livers, male rats received either, tap water, Cd, Cd+Zn, Cd+Se or Cd+Zn+Se in their drinking water, for 35 days. The activities of total superoxide dismutase (SOD), copper, zinc-superoxide dismutase (CuZn SOD), glutathione peroxidase (GPx) and catalase (CAT), malondialdehyde (MDA) level and the ratio of CuZn SOD to GPx activity, were determined in the liver. Exposure to Cd lowered total SOD, CuZn SOD, GPx and CAT activities, while it increased MDA level and the ratio of CuZn SOD to GPx activity, in the organ studied. With Se or Zn administration during exposure to Cd, only partial corrective effects on Cd-induced oxidative stress in the liver have been observed, while Se and Zn together assured a more efficient protection of the organ against the observed oxidative stress.

The impact of element-element interactions on antioxidant enzymatic activity in the blood of white stork (Ciconia ciconia) chicks

The aim of this work was to determine interrelationships among macroelements Na, K, Ca, Mg, and Fe, microelements Zn, Cu, Mn, and Co, and toxic heavy metals Pb and Cd in the blood of white stork Ciconia ciconia, during postnatal development, in different Polish environments, and their impact on the activity of antioxidant enzymes. We considered the content of thiobarbituric acid-reactive substances (TBARSs), i.e., malondialdehyde (MDA), and activity of superoxide dismutase (SOD), catalase (CAT), ceruloplasmine (CP), glutathione peroxidase (GPx), and glutathione reductase (GR). Blood samples were collected from storks developing at Odra meadows (Kłopot; southwestern Poland). They were compared with blood of chicks from several suburban sites located 20 km away from Zielona Góra (0.1 million inhabitants; southwestern Poland) and near Głogów, where a copper smelter is situated. We also conducted research in the Pomeranian region (Cecenowo; northern Poland). We collected blood samples via venipuncture of the brachial vein of chicks in 2005-2007. They were retrieved from the nest and placed in individual ventilated cotton sacks. The blood was collected using a 5-ml syringe washed with ethylenediaminetetraacetic acid (EDTA). We found significant interactions between macro- and microelements and enzymatic activity and TBARS products. We noticed the predominance of Cd and Pb participation in element-enzyme interactions. Simultaneously, we found interrelationships between cadmium and Na, K, Ca, Mg, and Fe and the activity of antioxidant enzymes SOD, CAT, CP, GR, and TBARS products in the blood of white stork chicks. In the case of lead these relationships were not numerous and they were significant for Ca, Mg, Cu, Mn, and Co. Correlations with enzymes were significant for Pb-CAT and Pb-TBARS. We noted that activities of most enzymes (SOD, CAT, CP, GR) and TBARS products are determined by their interactions with physiological elements Na, Ca, Mg, Fe, and Zn and toxic heavy metals. White stork chicks ranged in age from 17 to 59 days. Concentrations of elements in the blood were age related. Among enzymes, only SOD, CAT, and GPx were age related. Young storks differed in the case of element concentration (except for Ca, Zn, and Cd) and enzymatic activity. We found that significant element-element interaction/enzyme activity predominated in the case of physiological elements and toxic metals, which we explain by the intensive and prevailing access of toxic metals in redox reactions. This causes changes in the priority of these metals, reflected by their influence on the enzymatic activity of antioxidant enzymes. The content of Cd and Pb in blood of young storks from different regions tends to affect the lipid peroxidation process negatively. However, in many cases we observed an increase in enzymatic activity with an increase in heavy metals. This indicates the changes in oxidative stress intensity in chicks in response to environmental differentiation. The increase in lipoperoxidation modifies antioxidant enzyme activity and causes changes in SOD, CAT, CP, GPx, and GR activity in chicks from various regions, principally increases in enzyme activity in chicks from polluted environments and suburbs. We suggest that the source of heavy metals in chicks' blood might be used as a biological test system of adaptation to oxidative stress. We also report that a high level of heavy metals is accompanied by increased lipid peroxidation. Thus young storks are probably significantly susceptible to environmental conditions. They demonstrated initiation of lipoperoxidation and oxidative modification of proteins that coincide with chemical elements, as a possible antioxidant defense system.

Antioxidant responses in the nereidid Laeonereis acuta (Annelida, Polychaeta) after cadmium exposure

The objective of this study was to evaluate the effects of the exposure to cadmium on the antioxidant responses in the polychaeta Laeonereis acuta. The worms were submitted to 0, 5, and 100 microg of Cd/L during a period of test of 7 days. Cadmium was significantly (p<0.05) accumulated in L. acuta in both concentrations assayed, but the concentration of reactive oxygen and nitrogen species (RONS) increased (p<0.05) only in the group submitted to the highest concentration of cadmium (100 microg/L). At this concentration, a decrease in the activity of the superoxide dismutase and an increase of glutathione-S-transferase activity (p<0.05) was observed. The levels of both lipid peroxides and the activities of catalase and glutathione peroxidase were not affected (p>0.05) by the exposition to cadmium. Thus, cadmium can augment RONS levels and can interfere with the antioxidant defense system of the polychaete L. acuta, although cadmium does not directly induce oxidative stress unlike copper and iron.

The association of exposure to cadmium through cigarette smoke with pregnancy-induced hypertension in a selenium deficient population

Oxidative stress has been postulated as major contributor to endothelial dysfunction and pregnancy-induced hypertension. We have examined the association of exposure to cadmium through cigarette smoke with hypertension disorders during pregnancy in the selenium deficient population. Markers of lipid peroxidation and antioxidative defense were measured and correlated with cadmium blood concentration in normotensive and hypertensive pregnant smokers and nonsmokers. We have observed significantly higher blood Cd in hypertensive smokers and significant differences in all other parameters. Se concentrations were lower in smokers, both in normotensive and hypertensive group as well as values of nonenzymatic (Zn, Cu, and glutathione) and enzymatic (superoxide dismutase, glutathione peroxidase, and glutathione reductase) parameters of antioxidative defense. Results of the study indicate that exposure to cadmium through cigarette smoke in pregnant women, living in Se deficient areas is associated with significantly higher cadmium concentrations and lower levels of enzymatic and nonenzymatic antioxidants and that it can be considered as a risk factor for pregnancy-induced hypertension. Selenium supplementation should be considered for recommendation in such condition.

[Anemia induced by cadmium intoxication]

Anemia is commonly induced by chronic cadmium (Cd) intoxication. Three main factors are involved in the development of Cd-induced anemia: hemolytic, iron-deficiency, and renal. Intravascular hemolysis can occur at the early stage of Cd exposure owing to the direct damaging effect on erythrocytes. In addition, Cd that accumulates in erythrocytes affects membrane cytoskeletons and decreases cell deformability, and these cells are then trapped and destroyed in the spleen. Iron deficiency can be detected in animals after an oral exposure to Cd, which competes with iron for absorption in the intestines, leading to anemia. However, an increase in body iron content along with anemia is often observed in cases of parenteral exposure or itai-itai disease. Therefore, it is estimated that Cd disrupts the efficient usage of iron in hemoglobin synthesis in the body. Renal anemia is observed during the very last phase of chronic, severe Cd intoxication, such as itai-itai disease, showing a decrease in the production of erythropoietin from renal tubular cells. Because the renal anemia is based on the same pathophysiology as Cd-induced osteomalacia, which is derived from the disturbance of mineral metabolism due to renal tubular dysfunction, it is reasonable to include renal anemia in the criteria for the diagnosis of itai-itai disease. Hemodilution could also contribute to the development of Cd-induced anemia. Bone marrow hypoplasia or the inhibition of heme synthesis might only be involved in Cd-induced anemia in severe cases of Cd intoxication.

Elevated Urinary Levels of Vitamin D-Binding Protein in the Inhabitants of a Cadmium Polluted Area, Jinzu River Basin, Japan

Environmental cadmium (Cd) pollution and its effects on human health are still important issues. The most severe and representative manifestation of chronic Cd intoxication is Itai-itai disease, which is a syndrome that includes renal tubular dysfunction, osteomalacia, and generalized pain due to multiple bone fractures. The whole mechanism of how renal dysfunction relates to the development of bone lesions is unresolved. Vitamin D-binding protein (DBP) binds, transports and activates vitamin D, which plays a major role in calcium homeostasis and bone turnover. In this study, we measured urinary DBP levels and investigated their relationship to the markers of renal tubular dysfunction in the inhabitants of a Cd-polluted Jinzu River basin in Toyama Prefecture, Japan (Cd group). We also investigated age-matched subjects from an area known to have lower levels of Cd pollution (reference group). Urinary DBP was measured by a fluorometric enzyme-linked immunosorbent assay (ELISA), which was established in our laboratory. Significantly higher levels of urinary DBP were observed in the Cd group compared to the reference group. We observed significant positive correlations between urinary levels of DBP and renal tubular dysfunction markers in both groups. In the Cd group, urinary levels of DBP had a negative correlation with serum phosphate value. These results indicate that excretion of urinary DBP is increased after long-term Cd exposure and that the loss of DBP in urine may be linked to renal tubular dysfunction and possibly bone lesions in the inhabitants of Cd-polluted areas.

The Threshold Cadmium Level That Causes a Substantial Increase in .BETA.2-Microglobulin in Urine of General Populations

Cadmium (Cd) is a toxic element ubiquitous in the environment, and general populations have been exposed to this element primarily via foods. Thus, the critical level of non-occupational Cd exposure to cause any health effects among general populations is of public health as well as toxicological concern. The objectives of the present study were to examine the quantitative relationship between cadmium (Cd-U) and beta2-microglobulin in urine (beta2-MG-U) as a marker of exposure to Cd and as a marker of renal tubular dysfunction, respectively, and to identify a threshold Cd-U, if present, in causing a substantial increase in beta2-MG-U. Thus, paired data on geometric mean (GM) Cd-Ucr (i.e., Cd-U as corrected for creatinine [cr] concentration) and GM beta2-MG-Ucr (beta2-MG-U as corrected for cr) of residents in polluted as well as nonpolluted areas in Japan were retrieved in international and domestic sources. In practice, 245 cases of the data pairs were obtained in 51 articles published since 1975. Statistical analysis on ordinary scales disclosed that beta2-MG-Ucr increased markedly when Cd-Ucr exceeded a certain level. The relation between the two parameters after double-logarithmic conversion was in a shape of the letter J or a stick for ice hockey. Analysis for Cd-Ucr at the flexion point gave Cd-Ucr of 4 (on double logarithmic scales) or 7 microg/g cr (on ordinary scales). Cd-Ucr levels that correspond to a beta2-MG-Ucr of 1,000 microg/g cr were estimated to be 8-9 microg/g cr, by ordinary and logarithmic assumption as well as by the 3rd degree regression analysis. Thus, it is concluded that there is a threshold Cd-Ucr level that leads to a substantial increase in beta2-MG-Ucr, and that the threshold level is greater than 4 microg/g cr.