Hospital-based screening to detect patients with cadmium nephropathy in cadmium-polluted areas in Japan.

BACKGROUND: In health examinations for local inhabitants in cadmium-polluted areas, only healthy people are investigated, suggesting that patients with severe cadmium nephropathy or itai-itai disease may be overlooked. Therefore, we performed hospital-based screening to detect patients with cadmium nephropathy in two core medical institutes in cadmium-polluted areas in Akita prefecture, Japan. METHODS: Subjects for this screening were selected from patients aged 60 years or older with elevated serum creatinine levels and no definite renal diseases. We enrolled 35 subjects from a hospital in Odate city and 22 from a clinic in Kosaka town. Urinary ß2-microglobulin and blood and urinary cadmium levels were measured. RESULTS: The criteria for renal tubular dysfunction and the over-accumulation of cadmium were set as a urinary ß2-microglobulin level higher than 10,000 µg/g cr. and a blood cadmium level higher than 6 µg/L or urinary cadmium level higher than 10 µg/g cr., respectively. Subjects who fulfilled both criteria were diagnosed with cadmium nephropathy. Six out of 57 patients (10.5% of all subjects) had cadmium nephropathy. CONCLUSIONS: This hospital-based screening is a very effective strategy for detecting patients with cadmium nephropathy in cadmium-polluted areas, playing a complementary role in health examinations for local inhabitants. REGISTRATION NUMBER: No. 6, date of registration: 6 June, 2010 (Akita Rosai Hospital), and No. 1117, date of registration: 26 December, 2013 (Akita University).

Identifying early urinary metabolic changes with long-term environmental exposure to cadmium by mass-spectrometry-based metabolomics.

Cadmium (Cd) is a common environmental pollutant, and urinary Cd (UCd) is generally used as a marker of exposure; however, our understanding on the related urinary metabolic changes caused by Cd exposure is still not clear. In this study, we applied a mass-spectrometry-based metabolomic approach to assess the urinary metabolic changes in human with long-term environmental Cd exposure, aimed to identify early biomarkers to assess Cd nephrotoxicity. Urine samples from 94 female never smokers aged 44-70 with UCd in the range of 0.20-68.67 µg/L were analyzed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-ToF-MS) and gas chromatography-mass spectrometry (GC-MS). It was found that metabolites related to amino acid metabolism (L-glutamine, L-cystine, L-tyrosine, N-methyl-L-histidine, L-histidinol, taurine, phenylacetylglutamine, hippurate, and pyroglutamic acid), galactose metabolism (D-galactose and myo-inositol), purine metabolism (xanthine, urea, and deoxyadenosine monophosphate), creatine pathway (creatine and creatinine), and steroid hormone biosynthesis (17-α-hydroxyprogesterone, tetrahydrocortisone, estrone, and corticosterone) were significantly higher among those with a UCd level higher than 5 µg/L. Moreover, we noticed that the level of N-methyl-L-histidine had already started to elevate among individuals with a UCd concentration of ≥2 µg/L. The overall findings illustrate that metabolomics offer a useful approach for revealing metabolic changes as a result of Cd exposure.

Cadmium exposure induces hematuria in Korean adults.

INTRODUCTION: Toxic heavy metals have adverse effects on human health. However, the risk of hematuria caused by heavy metal exposure has not been evaluated. METHODS: Data from 4701 Korean adults were obtained in the Korean National Health and Nutritional Examination Survey (2008-2010). Blood levels of the toxic heavy metals cadmium, lead, and mercury were measured. Hematuria was defined as a result of ≥+1 on a urine dipstick test. The odds ratios (ORs) for hematuria were measured according to the blood heavy metal levels after adjusting for multiple variables. RESULTS: Individuals with blood cadmium levels in the 3rd and 4th quartiles had a greater OR for hematuria than those in the 1st quartile group: 3rd quartile, 1.35 (1.019-1.777; P=0.037); 4th quartile, 1.52 (1.140-2.017; P=0.004). When blood cadmium was considered as a log-transformed continuous variable, the correlation between blood cadmium and hematuria was significant: OR, 1.97 (1.224-3.160; Ptrend=0.005). In contrast, no significant correlations between hematuria and blood lead or mercury were found in the multivariate analyses. DISCUSSION: The present study shows that high cadmium exposure is associated with a risk of hematuria.

[Analysis of clinical features of mild chronic cadmium poisoning induced by different causes].

OBJECTIVE: To analyze the clinical features of mild chronic cadmium poisoning induced by different causes. METHODS: A total of 90 patients with mild chronic cadmium poisoning, who were hospitalized in our center from 2008 to 2011 and had complete clinical data, were divided into two groups according to the causes of poisoning: environmental pollution group (n = 45) and occupational poisoning group (n = 45). The clinical symptoms, signs, laboratory indices, and treatment outcomes of all patients were analyzed. RESULTS: Compared with the environmental pollution group, the occupational poisoning group had more bone pain, less bone injury (based on imaging findings), and significantly increased abnormal rate of urinary retinol-binding protein (RBP) (P < 0.05); there were no significant differences in urinary ß-2 microglobulin (MG) and urinary microalbumin between the two groups (P > 0.05). Urinary cadmium, urinary RBP, and urinary ß-2 MG had no linear correlation between each other in the two groups. Both groups showed significant changes in urinary cadmium levels after treatment (P < 0.05). CONCLUSION: The clinical features of mild chronic cadmium poisoning induced by various causes are different, and active nutritional support therapy plays a positive role in improving prognosis.

A polymorphism in metallothionein 1A (MT1A) is associated with cadmium-related excretion of urinary beta 2-microglobulin.

OBJECTIVES: Cadmium (Cd) toxicity of the kidney varies between individuals despite similar exposure levels. In humans Cd is mainly bound to metallothioneins (MT), which scavenge its toxic effects. Here we analyzed whether polymorphisms in MT genes MT1A and MT2A influence Cd-related kidney damage. METHODS: In a cross-sectional study N=512 volunteers were selected from three areas in South-Eastern China, which to varying degree were Cd-polluted from a smelter (control area [median Cd in urine U-Cd=2.67 µg/L], moderately [U-Cd=4.23 µg/L] and highly [U-Cd=9.13 µg/L] polluted areas). U-Cd and blood Cd (B-Cd) concentrations were measured by graphite-furnace atomic absorption spectrometry. MT1A rs11076161 (G/A), MT2A rs10636 (G/C) and MT2A rs28366003 (A/G) were determined by Taqman assays; urinary N-Acetyl-beta-(D)-Glucosaminidase (UNAG) by spectrometry, and urinary ß2-microglobulin (UB2M) by ELISA. RESULTS: Higher B-Cd (natural log-transformed) with increasing number of MT1A rs11076161 A-alleles was found in the highly polluted group (p-value trend=0.033; all p-values adjusted for age, sex, and smoking). In a linear model a significant interaction between rs11076161 genotype and B-Cd was found for UNAG (p=0.001) and UB2M concentrations (p=0.001). Carriers of the rs11076161 AA genotype showed steeper slopes for the associations between Cd in blood and natural log-transformed UB2M (ß=1.2, 95% CI 0.72-1.6) compared to GG carriers (ß=0.30, 95% CI 0.15-0.45). Also for UNAG (natural log-transformed) carriers of the AA genotype had steeper slopes (ß=0.55, 95% CI 0.27-0.84) compared to GG carriers (ß=0.018, 95% CI -0.79-0.11). CONCLUSIONS: MT1A rs11076161 was associated with B-Cd concentrations and Cd-induced kidney toxicity at high exposure levels.

The relationship between the bone mineral density and urinary cadmium concentration of residents in an industrial complex.

BACKGROUND: An association between cadmium exposure and bone mineral density (BMD) has been demonstrated in elderly women, but has not been well studied in youths and men. Some studies report either no or a weak association between cadmium exposure and bone damage. OBJECTIVES: This study was designed to investigate the relationship between the urinary cadmium (U-Cd) levels and BMD of females and males of all ages. METHODS: A total of 804 residents near an industrial complex were surveyed in 2007. U-Cd and BMD on the heel (non-dominant calcaneus) were analyzed with AAS-GTA and Dual-Energy X-ray absorptiometry, respectively. Demographic characteristics were collected by structured questionnaires. Osteoporosis and osteopenia were defined by BMD cut-off values and T-scores set by the WHO; T score>-1, normal; -2.5

Cadmium exposure in association with history of stroke and heart failure.

BACKGROUND: It is unclear whether environmental cadmium exposure is associated with cardiovascular disease, although recent data suggest associations with myocardial infarction and peripheral arterial disease. OBJECTIVE: The objective of this study was to evaluate the association of measured cadmium exposure with stroke and heart failure (HF) in the general population. METHODS: We analyzed data from 12,049 participants, aged 30 years and older, in the 1999-2006 National Health and Nutrition Examination Survey (NHANES) for whom information was available on body mass index, smoking status, alcohol consumption, and socio-demographic characteristics. RESULTS: At their interviews, 492 persons reported a history of stroke, and 471 a history of HF. After adjusting for demographic and cardiovascular risk factors, a 50% increase in blood cadmium corresponded to a 35% increased odds of prevalent stroke [OR: 1.35; 95% confidence interval (CI): 1.12-1.65] and a 50% increase in urinary cadmium corresponded to a 9% increase in prevalent stroke [OR: 1.09; 95% CI: 1.00-1.19]. This association was higher among women [OR: 1.38; 95% CI: 1.11-1.72] than men [OR: 1.30; 95% CI: 0.93-1.79] (p-value for interaction=0.05). A 50% increase in blood cadmium corresponded to a 48% increased odds of prevalent HF [OR: 1.48; 95% CI: 1.17-1.87] and a 50% increase in urinary cadmium corresponded to a 12% increase in prevalent HF [OR: 1.12; 95% CI: 1.03-1.20], with no difference in sex-specific associations. CONCLUSIONS: Environmental exposure to cadmium was associated with significantly increased stroke and heart failure prevalence. Cadmium exposure may increase these important manifestations of cardiovascular disease.

Latest status of cadmium accumulation and its effects on kidneys, bone, and erythropoiesis in inhabitants of the formerly cadmium-polluted Jinzu River Basin in Toyama, Japan, after restoration of rice paddies.

PURPOSE: The cadmium-polluted Jinzu River Basin in Toyama, Japan, where nephropathy and itai-itai disease were endemic among resident farmers decades ago, has been almost completely restored. The aim of this study is to investigate whether inhabitants there would still exhibit cadmium accumulation and its effects on kidneys, bones, and erythropoiesis. METHODS: We performed a cross-sectional study of 150 subjects from the polluted area and 144 controls from the same prefecture. Participants included female inhabitants from 34 to 74 years of age who underwent examinations to gather anthropometrical and medical information, obtain rice, blood and urine samples, and measure bone mineral density. RESULTS: Cadmium concentration in rice from the polluted area was lower than the level in the control area. Blood and urinary cadmium and urinary ß(2)-microglobulin levels were higher in subjects from the polluted area than controls, and the urinary ß(2)-microglobulin was independently affected by urinary cadmium. Bone mineral density did not differ between the two areas, but it was affected by renal tubular function in subjects from the polluted area. Serum bone alkaline phosphatase was lower in subjects from the polluted area compared to controls. We detected three cases of cadmium nephropathy among the subjects. One of them suffered from a renal anemia type of itai-itai disease. CONCLUSION: Inhabitants in the formerly polluted area still had high cadmium accumulations and showed a characteristic natural history of chronic cadmium toxicity, indicating that the risk remains for developing nephropathy or itai-itai disease in the future.

[Clinical and biochemical syndromes of cadmium-induced acute porphyrinopathy].

AIM: To study the specific features of porphyrin metabolic disturbances in cadmium poisoning. MATERIAL AND METHODS: The paper describes a patient who has developed clinical and biochemical syndromes of acute porphyrinopathy after exposure to cadmium-containing paint the vapors. The levels of delta-aminolevulinic acid, porphobilinogen, coproporphyrin, and uroporphyrin in urine and those of coproporphyrin and protoporphyrin in feces were measured. The concentrations of lead, cadmium, and copper were determined in whole blood and urine; selective screening of amino acids for hereditary metabolic diseases was made. RESULTS: The clinical signs of acute porphyrinopathy developed in the patient mimicked those of acute porphyries known by the current classification. The biochemical syndrome more corresponded to lead poisoning. However, the blood and urinary lead levels were not greater than the normal values, but the blood showed a 4-fold increase in cadmium, which seemed to induce porphyrin dysmetabolism.

The Effects of a Workplace Health Promotion Program to Decrease Cadmium Exposure Levels in Nickel-Cadmium Battery Workers.

OBJECTIVE: Cadmium exposure is a common problem in the production of nickel-cadmium batteries. However, keeping the respective legislative occupational and safety policies is essential, but there are problems with compliance. We analysed the effect of strategies to increase compliance with precautions during 20132015 on 59 workers at a nickel-cadmium battery factory. MATERIAL AND METHODS: A health promotion program was implemented in two phases. The first phase included comprehensive education on the importance of appropriate behaviour and changes to the sanitation program. The second phase included renovation of sanitary facilities and modernization of the air exhaust ventilation. RESULTS: The initial median cadmium urinary level in workers was 1.9 µg/g creatinine. After the first phase of interventions, levels dropped to 1.0 µg/g creatinine. After the second phase no significant further decrease was observed. CONCLUSION: Comprehensive education and changes in the sanitation program were able to halve cadmium levels and can be considered a useful and cost-effective preventive tool.

Differentiation of glomerular, tubular, and normal proteinuria: determinations of urinary excretion of beta-2-macroglobulin, albumin, and total protein.

A low molecular weight beta(2)-globulin (beta(2)-microglobulin), albumin, and total protein were measured in concentrated 24-hr urine specimens from 20 healthy subjects and 30 patients with clinical proteinuria of glomerular or tubular type. Classification of proteinuria was made on the basis of clinical diagnosis and size distribution of urinary proteins after gel chromatography. The molecular radii (Stokes' radii) of beta(2)-microglobulin and albumin, estimated by gel chromatography, were 15 A and 35 A. The average 24-hr urinary excretion in healthy subjects was 0.12 mg for beta(2)-microglobulin, 10 mg for albumin, and 80 mg for total protein. The patients with renal glomerular disorders had normal or only somewhat increased excretion of beta(2)-microglobulin, despite considerably increased excretion of albumin and total protein. Most of the patients with tubular dysfunction excreted large amounts of beta(2)-microglobulin, although they excreted normal or only slightly increased amounts of albumin and only moderately increased quantities of total protein. Consequently, the ratio or urinary albumin/urinary beta(2)-microglobulin was high in glomerular proteinuria (1100: 14,200), intermediate in normal proteinuria (33: 163), and low in tubular proteinuria (1.0: 13.3). Determinations of urinary clearances of beta(2)-microglobulin and albumin in four healthy subjects and 11 patients indicated that increased excretions of the two proteins were associated with increased clearances. The results suggest that quantitative determinations of urinary beta(2)-microglobulin and urinary albumin may be useful for detecting disorders of the renal handling of plasma proteins. The findings also seem to suggest a selective tubular reabsorption of the two proteins. Estimates on sera revealed a close correlation between serum levels of beta(2)-microglobulin and creatinine and also a greatly raised serum concentration of beta(2)-microglobulin after bilateral nephrectomy.

Noninvasive Biomarker Candidates for Cadmium-Induced Nephrotoxicity by 2DE/MALDI-TOF-MS and SILAC/LC-MS Proteomic Analyses.

Cadmium (Cd(2+)) is a major environmental pollutant that induces cytotoxicity by heavy-metal accumulation. Prolonged Cd(2+) exposure leads to cell damage by oxidative stress mainly in the kidneys, a critical organ for detoxification. To identify reliable on invasive protein biomarkers for Cd(2+)-induced nephrotoxicity, we performed 2-dimensional gel electrophoresis/matrix-assisted laser desorption/ionization time of flight mass spectra and stable isotope labeling by amino acids in cell culture/liquid chromatography-mass spectrometry analyses using conditioned media (CM) of HK-2 human kidney epithelial cells treated with CdCl2. Here, we identified heat shock cognate 71 kDa protein isoform1 (HSPA8) and α-enolase (ENO1) as potential biomarker candidates for the evaluation of Cd(2+)-induced nephrotoxicity. Treatment with CdCl2 increased the protein level of HSPA8 in CM and lysates of HK-2 cells. The mRNA level of HSPA8 was also increased by CdCl2 treatment, indicating transcriptional regulation. The level of ENO1 was increased in CM, but not in lysates of CdCl2-treated HK-2 cells. CdCl2 did not affect the mRNA level of ENO1. We provide evidence that the increases of HSPA8 and ENO1 in CM were due to Cd(2+)-induced cell death through oxidative stress. The increases of HSPA8 and ENO1 levels were also detected in CM of HK-2 cells treated with other nephrotoxic agents, such as HgCl2, NaAsO2, cisplatin, amphotericin B, and cyclosporine A. Urine and kidney tissues of CdCl2-treated rats showed increased levels of HSPA8. Taken together, this study identified HSPA8 and ENO1 as noninvasive biomarker candidates by 2 comparative proteomic analyses. These new biomarker candidates may have potential as alternatives to traditional biomarkers for the efficient and sensitive assessment of nephrotoxicity.

Increased urinary beta 2-microglobulin in cadmium exposure: dose-effect relationship and biological significance of beta 2-microglobulin.

A study on the general population from both cadmium-polluted and control areas and on cadmium alloy workers indicates that beta 2-MG in urine is very closely correlated with aging, but it indicates an association with cadmium exposure. However, the age factor is stronger than cadmium exposre in both polluted and control areas among persons without clinical proteinuria. On the other hand, cadmium exposure is most likely correlated with beta 2-MG even in nonpolluted areas. Thus it seems that there is no noneffect level of cadmium dose in affecting the elevation of beta 2-MG in urine. beta 2-MG in serum indicated a very close correlation with cadmium in blood among cadmium alloy workers. This may suggest that an increase of beta 2-MG in both blood and urine in an early stage of cadmium exposure is caused by the increased level of beta 2-MG in blood, which may be a result of stimulation due to cadmium, but not necessarily by the clinical dysfunction of reabsorption of beta 2-MG in the renal.

A study of the relationship between cadmium concentrations in urine and renal effects of cadmium.

The relationship between urinary cadmium concentration expressed as microgram/g creatinine and renal effects of cadmium exposure was studied in 542 inhabitants over 20 years of age who lived in the Jinzu River basin which is polluted by cadmium. Cadmium concentration in urine was employed as the index of cadmium exposure. Total protein with glucose, beta 2-microglobulin, retinol binding protein, and proline served as indices of renal effects. The prevalent rate of high beta 2-microglobulin excretion was the highest among these indices both in men and women. Prevalence rates of indices of renal effects increased proportionally with increasing cadmium concentrations in urine and probit linear regression lines could be calculated between them. The urinary cadmium concentrations corresponding to 1% prevalence rates of indices of the renal effects were calculated by the regression line. For beta 2-microglobulin, 3.2 microgram Cd/g creatinine and 5.2 microgram Cd/g creatinine were obtained in men and women, respectively. This method may be useful for evaluating the risk of renal damage of exposed inhabitants.

Exposure and accumulation of cadmium in populations from Japan, the United States, and Sweden.

Studies were carried out in Japan, United States, and Sweden regarding comparability of analytical methods for cadmium, daily intake of cadmium via food, daily amount of cadmium in feces, concentrations of cadmium in different tissues and the body burden of cadmium, urinary excretion of cadmium and cadmium concentrations in blood. It was found that the cadmium intake via food among adults is about 35 mug/day in Japan (Tokyo) and about 17 mug/day in the U.S. (Dallas) and Sweden (Stockholm). It varies with age in a way similar to calorie intake. Body burden increases rapidly with age. The half-time of cadmium is longer in muscles than in liver or kidneys. In the cross-sectional population samples studied (smokers and nonsmokers mixed) the average cadmium body burden at age 45 was about 21 mg in Japan, 9 mg in the U.S., and 6 mg in Sweden. Among nonsmokers in the U.S. and Sweden the body burden at age 45 was about 5-6 mg. The difference in average body burden for smokers and nonsmokers is explained by differences in smoking habits. Cadmium excretion in urine was closely correlated with body burden and about 0.005-0.01% of body burden is excreted daily in urine. Cadmium concentration in the blood was a good indicator of average recent intake over a 3-month period. Neither blood cadmium nor urine cadmium changed immediately after an increase of exposure level.

Recent results of health examinations on the general population in cadmium-polluted and control areas in Japan.

Health examinations by a revised method aimed at detecting renal tubular dysfunctions more effectively were conducted on the general population aged 50 years and over in cadmium-polluted areas (1826 persons) and control areas (1611 persons) in four prefectures in Japan in 1976. Although detailed analysis of the data is not yet completed, some of the results obtained are described here. The prevalence of glucosuria and low molecular weight proteinuria, frequency of decreased % TRP, and cadmium concentrations in urine are higher in the cadmium-polluted areas than in the controls. Clinically diagnosed cases with tubular dysfunctions seem to follow the same trend as above, though these cases are very few in number and they are limited to the advanced age group. When cadmium concentration in rice is taken as an index, a dose-response relationship is not necessarity explicit in the observations by prefecture. However, suggestive data are obtained in the observation by district in one cadmium-polluted area.

Urinary excretion of retinol-binding protein (RBP) in rabbit chronically poisoned with cadmium. Isolation and partial characterization of rabbit RBP.

Studies were conducted to induce urinary excretion of retinol-binding protein (RBP) in the rabbit by long-term administration of cadmium, and to isolate and characterize rabbit RBP. Two rabbits were exposed to Cd at a dose of 0.8 and/or 1.5mg/kg of body weight by means of subcutaneous injections five times per week. One rabbit excreted large amounts of protein (0.8 to 1.6 g/day) from days 80 to 118. The electrophoretic patterns of the urinary protein showed two fluorescent bands specific for protein-bound retinol in the alpha-region; these were presumed to be RBP. Rabbit RBP was isolated from the pooled urine (10.3 liters) by a sequence of procedures which included gel filtration on Sephadex G-100 and chromatography on DEAE- and SP-Sephadex. Purified RBP (20 mg) was found to be homogeneous by physical and immunological criteria. The RBP had alpha-mobility, with a molecular weight of approximately 20,000. The properties of rabbit RBP resembled those of human RBP simultaneously isolated from the urine of patients with "Itai-Itai" disease in many ways: ultraviolet and fluorescence spectra, and amino acid compositions. A monospecific anti-rabbit RBP antiserum was raised in a goat. There was no immunological cross-reactivity between rabbit and human RBP. The molecular size of the retinol-containing protein in fresh rabbit serum was estimated to be about 60,000 to 70,000 by gel filtration on Sephadex G-200. Rabbit RBP in the serum was also shown to be immunologically identical with purified RBP from the urine.

Hypercalciuria related to cadmium exposure.

A work force has been investigated for possible cadmium intoxication. One group who are coppersmiths have an 18.5 per cent prevalence of upper urinary tract stone disease associated with a statistically highly significant hypercalciuria and reduced serum inorganic phosphate. Proof of exposure to cadmium has been confirmed in all workers. The trace element cadmium should be kept in mind when investigating stone formers who exhibit an unexplained hypercalciuria.

A solid-phase radioimmunoassay for human beta2-microglobulin.

A simple and relatively rapid as well as highly reproducible determination of beta2-microglobulin is described for general laboratory use. The method is based on a solid-phase radioimmunoassay paper discs as a solid-phase material. The assayable range is approximately in the range of 2 ng to 20 mug of beta2-microglobulin with a precision of approx. 5 percent. This assay requiring only 0.05 ml of urine can be completed within 20 h. Urine in cadmium-exposed workers and residents in cadmium-polluted districts including patients with itai-itai disease were examined and considerable amounts of beta2-microglobulin were observed in these urines.

Determination of cadmium in whole blood and urine by Zeeman atomic absorption spectroscopy.

Direct determination of cadmium in whole blood and urine can be achieved using Zeeman effect flameless atomic absorption spectroscopy. Within-run precision studies for whole blood cadmium determinations gave relative standard deviations of 11.3% and 6.3% for 0.53 micrograms/l and 3.16 micrograms/l, respectively. Within-run precision studies for the urine analyses yielded relative standard deviations of 11.3% and 5.2% for 0.62 micrograms/l and 2.48 micrograms/l, respectively. The detection limit is 0.12 micrograms/l in the diluted specimens. Thus, this methodology may be used to quantitate normal and toxic cadmium levels in whole blood and urine.