Can zinc supplementation ameliorate cadmium-induced alterations in the bioelement content in rabbits?

Cadmium dietary exposure assessment in the adult population and pre-school children in the Republic of Serbia

Cadmium (Cd) is a toxic metal, present in all matrices of the environment and a common food contaminant. Human exposure to it may elicit many diverse health impairments. The aim of this study was to assess the dietary exposure to Cd for the adult population and preschool children in Serbia using probabilistic methodology. We measured Cd in 11,227 food samples belonging to 50 food items on the Serbian market. Cd was detected in 90% of the tested food items, and in 30.8% of the overall tested samples. The food item that contributed the most to total dietary Cd intake was potatoes (median Cd concentration of 7 ng/g) in adults, and fruit and vegetable juices in children (median Cd concentration of 19 ng/g). Weekly Cd intake shown as 50th and 95th percentiles were 2.54 and 4.74 µg/kg bw in the adult population, and 3.29 and 4.93 µg/kg bw in children. The results of this study are rather preliminary and should be considered as an indication of the need for further, more refined research, which would contribute to a more realistic risk assessment as a high-priority approach, especially in the case of vulnerable subpopulations such as children. Abbreviations: AT SDR: Agency for Toxic Substances and Disease Registry; EEA: European Environment Agency; EFSA: European Food Safety Authority; FAO/WHO: Food and Agriculture Organization/World Health Organization; HI: hazard index; IARC: International Agency for Research on Cancer; JECFA: Joint FAO/WHO Expert Committee on Food Additives; LOD: limit of detection; Cd: cadmium; TWI: tolerable weekly intake; UNEP: United Nations Environment Program; WI: weekly intake.

Ginkgo biloba Supplement Reverses Lead (II) Acetate-Induced Haematological Imbalances, Hepatic and Renal Dysfunctions in Male Wistar Rat

Lead is a heavy metal abundant in nature that causes haematological imbalances, and hepatic and renal dysfunction, and this imbalance has been linked to oxidative stress. Several reports have shown that natural products are implicated in ameliorating metal poisonings. Ginkgo biloba is a flavonoid-rich natural herbal supplement with several pharmacological properties. The present study investigated effect of Ginkgo biloba supplement (GBS) on lead-induced toxicity. Animals were given a lead dose of 25 mg/kg for 14 days orally and then given Ginkgo biloba supplements of 50 mg/kg and 100 mg/kg orally for 14 days. Animals given GBS had significantly improved haematological and rheological parameters. GBS showed a protective impact in terms of improved kidney and liver histology, anti-oxidant enzyme activity (CAT, SOD, GSH, and MDA), organ function indices, and a lower rate of erythrocyte osmotic fragility. Conclusively, Ginkgo biloba supplementation attenuated lead toxicity by normalization of haematological imbalances, and hepatic and renal dysfunction as well as maintaining erythrocyte membrane integrity.

Genotoxic Effect of Cadmium and Zinc in the Peripheral Erythrocytes of Prussian Carp (Carassius Gibelio B.)

Introduction

Cadmium and zinc are often found in aquatic environment and may accumulate in living organisms. The aim of this study was to evaluate the genotoxic effect of Cd, Zn, and their binary mixture on the peripheral blood erythrocytes of Prussian carp (Carassius gibelio B.).

Material and Methods

The fish were exposed to 4.0 mg/L Cd, 4.0 mg/L Zn or a mixture of 4.0 mg/L Cd and 4.0 mg/L Zn for a period of 14, 21 or 28 days. Genotoxic effects were investigated in peripheral blood cells using the comet assay and the erythrocyte micronucleus assay.

Results

The results demonstrated that the frequencies of micronuclei (MN) and both nuclear and cellular abnormalities in erythrocytes were significantly higher in all exposure groups as compared to the control group. The fish exposed to the mixture of Cd and Zn presented the highest frequency of MN. Furthermore, there was a decrease in the frequency of MN and an increase in the occurrence of DNA integrity defects (DNA damage) with longer time of exposure to the metals studied.

Conclusion

Erythrocyte micronucleus and comet assays confirmed the genotoxicity of Cd and Zn. The results of the tests applied (which showed considerable variability) suggest the involvement of various toxicity mechanisms. Therefore, an integrative and comprehensive approach, using a set of assays for toxicity profile determination, should be adopted during ecotoxicological studies and environmental risk assessment pertaining to these elements.

Estimation of Bone Trace Elements Following Prolonged Every-other Day Feeding in C57BL/6 Male and Female Mice

The purpose of this study was to examine the effect of prolonged every-other day (EOD) feeding on bone trace elements. Four-week old C57BL/6 female (n = 12) and male (n = 12) mice were employed in this experiment. Animals were assigned to four groups: ad libitum-AL (males and females), EOD fed (males, females). After 9 months, the mice were sacrificed. Long bones (humerus and radius) were isolated and prepared for analysis using inductively coupled plasma optical emission spectrometry to determine the Fe, Zn, Mo, Co, Cu, Mn, Cr contents. Estimation of cathepsin K expression on bone slides was performed to determine the activity of osteoclasts in bones of EOD- and AL-fed animals. Higher content of Fe in EOD-fed females compared to AL-fed females was found. In EOD-fed males, a significantly higher amount of Mo (p < 0.005) and Co (p < 0.05) in comparison to AL-fed males was noted. Gender differences in amounts of trace elements in control AL-fed males vs. females were observed. EOD feeding influences the amount of some trace elements in long bones of female and male C57BL/6 mice. However, this is not influenced by the activity of bone cells.

Effects of multi-metal exposure on the risk of diabetes mellitus among people aged 40-75 years in rural areas in southwest China

INTRODUCTION

Metals play an important role in diabetes mellitus (DM). This cross-sectional study aims to evaluate the overall, individual, and interactive effects of multi-metal exposure on the prevalence of DM, impaired fasting glucose (IFG) rate, and fasting blood glucose (FBG) levels.

MATERIALS AND METHODS

The FBG levels of a study population from a cadmium (Cd)-polluted area (n=250) and an unpolluted area (n=204) and the metal levels, including magnesium (Mg), calcium (Ca), iron (Fe), zinc (Zn), arsenic (As), Cd, copper (Cu), and lead (Pb), in blood and urine were detected. The study population was divided into a normal fasting glucose (NFG) group, an IFG group, and a DM group on the basis of FBG levels.

RESULTS

IFG rate and DM prevalence were negatively associated with blood Cd and urine Zn levels (IFG rate: OR=0.780, 95%CI: 0.655-0.928; OR=0.622, 95%CI: 0.465-0.831. DM prevalence: OR=0.506, 95%CI: 0.288-0.888; OR=0.609, 95%CI: 0.395-0.939), IFG rate was positively associated with urine Fe levels (OR=1.876, 95%CI: 1.290-2.778), and DM prevalence was positively associated with urine Pb and blood Fe levels (OR=1.185, 95%CI: 1.022-1.376; OR=1.008, 95%CI: 1.001-1.014). A linear negative correlation was observed between FBG levels and blood Cd, and nonlinear inverted U-shaped associations were found between FBG levels and Zn, Pb, and Cu in urine.

CONCLUSIONS

This research suggests that multi-metal exposure, especially Cd, Fe, Zn, Cu, and Pb, is linked to DM, and the interactive effects of multiple metals need further exploration.

Effect of a Diet Supplemented with Nettle (Urtica dioica L.) or Fenugreek (Trigonella Foenum-Graecum L.) on the Content of Selected Heavy Metals in Liver and Rabbit Meat

The literature on herbal additives for rabbit feed offers little information on the use of nettle and fenugreek. Both of these herbs are valuable sources of vitamins and minerals. These herbs affect the growth, health, and meat quality of rabbits. They regulate the digestive system, stimulate the appetite, have a positive effect on the functioning of the immune system, and exhibit antibacterial activity. The purpose of the present study was to determine the effect of nettle (Urtica dioica L.) leaves or fenugreek (Trigonella foenum-graecum L.) seeds in the feed on the content of selected heavy metals in the liver and meat of the rabbit. The rabbits were divided into three groups: group C (n = 20; 10♂ and 10♀) was fed ad libitum with a complete feed, N group (n = 20; 10♂ and 10♀) was fed a complete mixture with 1% added nettle, and group F (n = 20; 10♂ and 10♀) was fed with a complete mixture with 1% added fenugreek. The experiment lasted 7 weeks (from the 35th to the 84th day of the rabbits’ lives). All the rabbits were slaughtered on the 84th day of age, with a body weight of about 2.6 kg. The concentration of heavy metals (Zn, Cu, Ni, Mn, Fe, Pb, Cd) was determined by the atomic absorption spectrometry (AAS). The additives to the feed significantly affected the content of elements in both the liver and the meat of rabbits (p < 0.05). The highest level of the heavy metals, regardless of the used diet, was recorded in the liver (p < 0.05). The meat (m. longissimus lumborum) and the liver of rabbits fed with herbal fodder contained less tested metals than in animals fed with fodder without additives (p < 0.05). Moreover, more essential metals were found in the liver of rabbits fed with fenugreek than rabbits fed with nettle. In the meat and liver of rabbits, the permissible content of cadmium and lead was not exceeded. Additionally, male livers had a significantly higher content of copper and manganese compared to female livers (p < 0.05). It is important to study the content of heavy metals in the used animal herbal feed additives and their interaction with each other, as they affect the distribution of elements in tissues and organs.

Oxidative stress, metallomics and blood toxicity after subacute low-level lead exposure in Wistar rats: Benchmark dose analyses

Exposure to lead (Pb) is still rising concern worldwide, having in mind that even low-dose exposure can induce various harmful effects. Thus, in-depth knowledge of the targets of Pb toxicity and corresponding mechanisms is essential. In the presented study, the six groups (male Wistar rats, n = 6) received 0.1; 0.5; 1; 3; 7; 15 mg Pb/kg body weight/day for 28 days, each day by oral gavage, while the control group received distilled water only. All animals were sacrificed 24 h after the treatment, and blood was collected for the analysis of hematological, biochemical, oxidative status and essential elements levels. An external and internal dose-response relationship was performed using PROASTweb 70.1 software. The results showed that low doses of Pb affect hematological parameters and lipid profile after 28 days. The possible mechanisms at examined Pb dose levels were a decrease in SOD, O₂^•- and Cu and an increase in Zn levels. The dose-dependent nature of changes in cholesterol, HDL cholesterol, O₂^.-, SOD, AOPP in serum and hemoglobin, Fe, Zn, Cu in blood were obtained in this study. The most sensitive parameters that were alerted are Cu blood levels (BMDL₅: 1.4 ng/kg b.w./day) and SOD activity (BMDL₅: 0.5 μg/kg b.w./day). The presented results provide information that may be useful in further assessing the health risks of low-level Pb exposure.

Possible zinc deficiency in the Serbian population: examination of body fluids, whole blood and solid tissues

Studies indicate that the soil, water and consequently foodstuffs in Serbia are significantly poor in zinc (Zn), and thus, it is likely that there is a Zn deficiency in the Serbian population. This study examined the Zn status in multiple clinical samples, including body fluids (serum, cerebrospinal fluid), whole blood and Zn-rich solid tissues (thyroid and brain tissue). Differences between sex and age were also considered, and comparative analysis of Zn status with other world populations was performed. Serum samples from a large number of Serbian adults approximately had twofold lower Zn amounts when compared to other populations. A similar trend was obtained for whole blood. Males had significantly higher amounts of Zn in serum, whole blood and thyroid tissue samples than females. Higher amounts of Zn were observed in the group older than 50 years. Importantly, in thyroid and brain tissues, Zn was 10- and 20-fold lower, respectively, than reported in the literature. Our results indicate that the population in Serbia could be considered Zn deficient. Therefore, adequate oral Zn supplementation and/or foodstuff fortification should be considered to prevent the deleterious effects caused by Zn deficiency.

Cadmium Accumulation and Depuration in the Muscle of Prussian Carp (Carassius gibelio Bloch) after Sub-Chronic Cadmium Exposure: Ameliorating Effect of Melatonin

Simple Summary

Rapid urbanization and industrialization has resulted in substantial contamination of various ecosystems, especially aquatic environments with heavy metals. Heavy metals are classified as either essential (iron, zinc, or copper) or non-essential (cadmium, lead, or mercury) for organisms. Cadmium is a toxic, cancerogenic, and mutagenic metal, occurring as anthropogenic contamination in aquatic environments. The level of cadmium uptake in animals depends on the rate at which they are accumulated and eliminated. Exceeding the permissible levels of cadmium in fish muscle may pose risks for human health in the case of contaminated fish consumption. The aim of the present study was to evaluate the influence of melatonin on cadmium accumulation and elimination in fish muscle. Prussian carps were exposed to two doses of cadmium in the presence or without the melatonin implants. This is the first study to report that melatonin co-administration can effectively protect fish from the accumulation of cadmium in muscle tissue, improve the accumulated cadmium depuration from muscle, and prevent disturbance of the concentration of essential metals in fish body.

Abstract

The aim of this study was to investigate the bioaccumulation of cadmium in the muscle tissue of Prussian carp during 7 and 13 weeks of exposure to different concentrations of this metal in water (0.4 and 4.0 mg/L), and the depuration of cadmium from muscle during the following 6-week depuration period in the presence of melatonin implants. Furthermore, the relationship between cadmium accumulation and the levels of essential bioelements (copper, zinc, iron) in muscle was evaluated, as well as the bioconcentration factor of cadmium. Heavy metal concentration was determined using atomic absorption spectrometry. Cadmium accumulation in fish muscle increased with the duration of exposure. Cd concentrations exceeded the permissible levels for human consumption in groups exposed to the higher concentration of this metal. Moreover, a significant increase of Zn and Fe levels in the muscle was observed. In the fish that received melatonin implants and were exposed to Cd, its level in the muscle was significantly lower. The depuration of accumulated cadmium depended mainly on the duration of the elimination period. This is the first study to report that melatonin co-administration can effectively protect the fish from the accumulation of cadmium in muscle tissue and changes in trace metal levels.

Effects of quercetin on the alterations of serum elements in chronic unpredictable mild stress-induced depressed rats

Depression is a common and serious psychiatric disorder, but current conventional antidepressants have limited efficacy and significant side effects. Thus, better antidepressants are urgently needed. This study aimed to investigate the antidepressant-like effects and potential mechanism of quercetin by evaluating the changes of serum elements in chronic unpredictable mild stress (CUMS) rats. Based on the results of the sucrose preference test (SPT), 96 rats were randomly assigned to six groups: control, different dosages of quercetin (10 and 50 mg/kg·bw, respectively), depressed, and different dosages quercetin plus depressed groups. After 8 weeks of CUMS modeling, rat serum was collected. Fifteen elements in serum were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and related enzyme indicators, antioxidant indicators, and inflammatory cytokines were detected to further explore the potential mechanism. Besides, the accuracy and precision of the method were evaluated. The results showed that the levels of iron (Fe), copper (Cu), and calcium (Ca) in serum significantly increased (p ≤ 0.001), while the levels of magnesium (Mg), zinc (Zn), selenium (Se), and cobalt (Co) significantly decreased (p ≤ 0.001) in depressed group compared with the control group. The levels of the remaining eight elements did not change significantly. When high-dose quercetin was administered to depressed rats, the levels of the above seven elements significantly restored (p ≤ 0.001). This study suggests that quercetin (50 mg/kg·bw) has a regulatory effect on serum elements in CUMS rats, which may be mediated by reducing oxidative stress, inhibiting inflammation, and regulating a variety of neurotransmitter systems.

Usage of atomic force microscopy for detection of the damaging effect of CdCl2 on red blood cells membrane

The possibility of detecting the damaging effect of cadmium salts on red blood cells (RBC) membrane by atomic force microscopy and light microscopy was studied. White wistar rats RBC were incubated with cadmium chloride in concentrations of 1 μg/l, 10 μg/l, 100 μg/l, and 1000 μg/l for the research. A comparison of sample preparation methods proposed by other authors in previous studies is made. The optimal method that does not significantly affect the change in the morphological features of the cell is selected. The quantitative assessment of damaged and destroyed RBC depending on the concentration of cadmium was performed by optical microscopy. The study showed that CdCl₂ has a damaging effect on the RBC membrane, which leads to the formation of non-specific cell forms. A comparative assessment was made between the methods of optical microscopy and atomic force microscopy for the suitability of studying the morphological characteristics of abnormal forms of the RBC. It is shown that the method of atomic force microscopy allows registering morphological changes in the RBC that cannot be registered by optical microscopy. It is pointed that CdCl₂ has effect on destruction of the RBC and the formation of specific bulges on the RBC membrane. Influence of CdCl₂ on the RBC mechanical properties was studied using atomic force microscopy. The possibility of using atomic force microscopy in studies of morphology and mechanical properties of the RBC under toxicity effect of cadmium is shown.

Redox and essential metal status in the brain of Wistar rats acutely exposed to a cadmium and lead mixture

Most Pb and Cd neurotoxicity studies investigate exposure to either of the toxic metals alone, while data on co-exposure are scarce. The aim of our study was to fill that gap by investigating acute combined effects of Pb and Cd on redox and essential metal status in the brain of Wistar rats. Animals were randomised in four groups of six to eight rats, which received 15 or 30 mg/kg of Cd, 150 mg/kg of Pb, or 150 mg/kg of Pb + 15 mg/kg of Cd by gavage. The fifth, control, group received distilled water only. Co-treatment with Pb and Cd induced significant increase in malondialdehyde (MDA) and thiobarbituric acid-reactive substances (TBARS) compared to control and groups receiving either metal alone. This is of special importance, as MDA presence in the brain has been implicated in many neurodegenerative disorders. The groups did not significantly differ in Zn, Cu, Mn, and Fe brain levels. Our findings highlight the importance of metal mixture studies. Neurotoxicity assessments of single chemicals do not provide a real insight into exposure to mixtures in real life. Further research should look into interactions between these metals to reveal complex molecular mechanisms of their neurotoxicity.

Emerging Links between Cadmium Exposure and Insulin Resistance: Human, Animal, and Cell Study Data

Recent research has helped clarify the role of cadmium (Cd) in various pathological states. We have demonstrated Cd involvement in pancreatic cancer, as well as the bioaccumulation of Cd in the pancreas. Bioaccumulation and increased toxicity suggest that Cd may also be involved in other pancreas-mediated diseases, like diabetes. Cd falls into the category of "hyperglycemic" metals, i.e., metals that increase blood glucose levels, which could be due to increased gluconeogenesis, damage to β-cells leading to reduced insulin production, or insulin resistance at target tissue resulting in a lack of glucose uptake. This review addresses the current evidence for the role of Cd, leading to insulin resistance from human, animal, and in vitro studies. Available data have shown that Cd may affect normal insulin function through multiple pathways. There is evidence that Cd exposure results in the perturbation of the enzymes and modulatory proteins involved in insulin signal transduction at the target tissue and mutations of the insulin receptor. Cd, through well-described mechanisms of oxidative stress, inflammation, and mitochondrial damage, may also alter insulin production in β-cells. More work is necessary to elucidate the mechanisms associated with Cd-mediated insulin resistance.

Hepatoprotective Effect of Oleuropein-Rich Extract from Olive Leaves against Cadmium-Induced Toxicity in Mice

Cadmium (Cd) is a harmful pollutant which mainly affects the liver and kidney. In this work, we investigated the hepatoprotective effects of olive leaf extract based on oleuropein against hepatic cadmium toxicity in mice. Three groups of animals were used: the first one served as the control (C); the second one received intraperitoneal injection of cadmium 2 mg/kg b.w. (CD), administered five times during two weeks; and the third group received the same doses of Cd and simultaneously 16 mg/kg b.w. of oleuropein. Results showed that Cd induced a significant increase in liver injury biomarkers coupled with enhanced lipid peroxidation (MDA) and significant depletion of antioxidants (CAT and SOD). Histological and immunohistochemical analysis confirmed these findings. In fact, we observed a severe central lobular apoptosis and inflammation around central veins. Cotreatment with oleuropein significantly reduced the oxidative damage induced by cadmium. Our findings suggest that oleuropein could be used in the prevention of Cd hepatotoxicity.

The influence of smoking habits on cadmium and lead blood levels in the Serbian adult people

According to the World Health Organization, in 2015, the Serbian population ranked among the highest ones in Europe in terms of smoking habit: 44.3% males and 36.2% females aged 18-64 smoked tobacco. In the last 7 years, 25% of total mortality in men and 9% in women from Serbia were associated with smoking. Tobacco smoking is one of the most important sources of exposure to many toxic substances in general population. Our study confirmed higher blood levels of two toxic metals, cadmium and lead, in the blood of smokers (3.5 and 1.5 times higher than in non-smokers, respectively). Furthermore, smoking habits, such as number of smoked cigarettes per day, smoking period and cigarette type, along with age, were shown to influence these metals' blood concentration. Higher blood levels of Cd and Pb were found in smokers consuming more than 10 cigarettes per day for more than 10 years. The present study also highlighted the importance of the controlled tobacco production, since it was shown that consumption of illicit tobacco could manifold the exposure to toxic metals that can subsequently increase the frequency of related diseases as well.

Thyroid dysfunction: how concentration of toxic and essential elements contribute to risk of hypothyroidism, hyperthyroidism, and thyroid cancer

This study was conducted to evaluate the levels of trace metals Fe, Cr, Co, Cd, Cu, Ni, Hg, Zn, and Pb in healthy individuals and patients with thyroid disease (hyperthyroidism, hypothyroidism, and cancerous). The serum levels of 110 participants living in Birjand City, east of Iran, were collected and analyzed using ICP-MS (Agilent 7900). Results showed that the concentration levels of Cr, Co, Zn, Cd, and Pb were significantly higher at case-patients (p < 0.05), but the levels of Fe, Ni, and Hg were similar between healthy and patient subjects (p > 0.05). In patients with high or low thyroid activity, strong mutual correlations between Cr, Ni, and Fe were noticeable (p < 0.05). In hypothyroid patients, no significant correlation between Zn and Hg, Co, and Cd was found, but Zn was moderately and positively correlated with other trace metals. The moderate negative correlations between Cd-Cr (p = - 0.46) and Cd-Fe (p = - 0.43) were also observed. Logistic regression analysis showed that the effect of Cr, Co, Pb, Cu, Zn, and Cd was significant in developing hyperthyroidism and hypothyroidism; whereas, in patients with thyroid cancer, the effect of Cr, Cd, and Pb was found to be significant. In conclusion, our findings suggest that toxic metals such as Pb, Cd, and Cr can increase the risk of developing hypothyroidism and thyroid cancer, but more research is needed to evaluate the potential toxicity mechanisms of Pb, Cd, and Cr.

A Review on Coordination Properties of Thiol-Containing Chelating Agents Towards Mercury, Cadmium, and Lead

The present article reviews the clinical use of thiol-based metal chelators in intoxications and overexposure with mercury (Hg), cadmium (Cd), and lead (Pb). Currently, very few commercially available pharmaceuticals can successfully reduce or prevent the toxicity of these metals. The metal chelator meso-2,3-dimercaptosuccinic acid (DMSA) is considerably less toxic than the classical agent British anti-Lewisite (BAL, 2,3-dimercaptopropanol) and is the recommended agent in poisonings with Pb and organic Hg. Its toxicity is also lower than that of DMPS (dimercaptopropane sulfonate), although DMPS is the recommended agent in acute poisonings with Hg salts. It is suggested that intracellular Cd deposits and cerebral deposits of inorganic Hg, to some extent, can be mobilized by a combination of antidotes, but clinical experience with such combinations are lacking. Alpha-lipoic acid (α-LA) has been suggested for toxic metal detoxification but is not considered a drug of choice in clinical practice. The molecular mechanisms and chemical equilibria of complex formation of the chelators with the metal ions Hg2+, Cd2+, and Pb2+ are reviewed since insight into these reactions can provide a basis for further development of therapeutics.

Long-term effects of chromium on morphological and immunological parameters of Wistar rats

Hexavalent chromium raises high concern because of its wide industrial applications and reported toxicity. Long-term (135 days) oral exposure of Wistar rats to chromium in the form of K₂Cr₂O₇ (exposed group~20 mg/kg/day) led to a decrease in thymus mass and thymocytes' number and caused structural and functional changes in the lymph nodes and spleen, namely lymphoreticular hyperplasia and plasmocytic macrophage transformation. Programmed cell death was increased in both thymocytes and splenocytes and decreased in lymphocytes in the T-zones of spleen and lymph nodes. Moreover, Cr (VI) administration decreased myeloid cells' and neutrophils' number, while it increased lymphoid and erythroid cells' number in bone marrow. Cr (VI) immune system effects seem to be related to oxidative stress induction, as depicted by the increased levels of diene conjugates and malondialdehyde in the spleen and liver and by the decreased activity of catalase and superoxide dismutase in rats' erythrocytes. In addition, exposure to Cr (VI) decreased copper, nickel and iron concentrations in blood and liver, while Cr levels in blood, spleen and liver were increased, as expected. The observed changes in the series of immunological parameters studied contribute to the development of new approaches for the prevention of low level Cr exposure toxicity.

Environmental cadmium exposure and pancreatic cancer: Evidence from case control, animal and in vitro studies

Although profoundly studied, etiology of pancreatic cancer (PC) is still rather scarce. Some of established risk factors of PC are connected to an increased cadmium (Cd) body burden. Hence, the aim of this study was to investigate the role of this environmental pollutant in PC development by conducting human observational, experimental and in vitro studies. The case-control study included 31 patients with a histologically based diagnosis of exocrine PC subjected to radical surgical intervention as cases and 29 accidental fatalities or subjects who died of a nonmalignant illness as controls. Animal study included two treated groups of Wistar rats (15 and 30 mg Cd/kg b.w) and untreated control group, sacrificed 24 h after single oral exposure. In in vitro study pancreas hTERT-HPNE and AsPC-1 cells were exposed to different Cd concentrations corresponding to levels measured in human cancerous pancreatic tissue. Cd content in cancer tissue significantly differed from the content in healthy controls. Odds ratio levels for PC development were 2.79 (95% CI 0.91-8.50) and 3.44 (95% CI 1.19-9.95) in the third and fourth quartiles of Cd distribution, respectively. Animal study confirmed Cd deposition in pancreatic tissue. In vitro studies revealed that Cd produces disturbances in intrinsic pathway of apoptotic activity and the elevation in oxidative stress in pancreatic cells. This study presents three different lines of evidence pointing towards Cd as an agent responsible for the development of PC.

Potential interaction of cadmium chloride with pancreatic mitochondria: Implications for pancreatic cancer

Pancreatic cancer (PC) is insidious with a high mortality rate due to the lack of symptomology prior to diagnosis. Mitochondrial involvement in PC development is becoming accepted, and exposure to cadmium (Cd) is suspected of being a risk factor for the development of PC; however, the mechanisms involved remain unclear. In this study, we examined the role of Cd as a mitochondrial toxicant and whether alterations in mitochondrial function may be an underlying cause for the development of PC. In this study, cadmium chloride (CdCl₂)-mediated toxicity in hTERT-HPNE and AsPC-1 pancreatic cell lines was determined by MTT assay. We also investigated the release of LDH and the generation of free radicals. Mitochondrial toxicity assays were performed in media containing glucose (25 mM) or galactose (10 mM) and following exposure to CdCl₂ (0-100 μM) followed by MTT assay. For the confirmation of mitochondrial toxicity, we measured the release of ATP following exposure to CdCl₂. Initial experiments confirmed that exposure to CdCl₂ did not reduce the viability of either cell line until a concentration of >10 μM was used. Non-linear analysis of the response curves revealed lethal concentration 50% (LC₅₀) values for CdCl₂ in the HPNE cells of 77 μM compared to 42 μM in the AsPC-1 cells (P<0.01). The CdCl₂-mediated mitochondrial toxic effects were greater in the HPNE cells, suggesting a heightened sensitivity to the effects of CdCl₂, not due to elevated oxidative stress. Increased mitochondrial toxic sensitivity was indicated by a 73.4% reduction in IC₅₀ values in the HPNE cells cultured in galactose compared to culture in glucose media, whereas the AsPC-1 cells exhibited a 58.8% reduction in IC₅₀ values. In addition, the higher concentration of CdCl₂ elicited a significant cell-dependent effect on ATP release in both cell lines, suggestive of CdCl₂ being a mitochondrial toxicant. Cell survival was unaffected following exposure to low concentrations of CdCl₂; however, exposure did alter mitochondrial function (control cells > tumor cells). Therefore, the findings of this study indicate that the mitochondria may be a site of action for cadmium in promoting tumor development.

Toxic Effect of Acute Cadmium and Lead Exposure in Rat Blood, Liver, and Kidney

Background: Cadmium and lead are widespread and non-biodegradable pollutants of great concern to human health. In real life scenarios, we are exposed to mixtures of chemicals rather than single chemicals, and it is therefore of paramount importance to assess their toxicity. In this study, we investigated the toxicity of Cd and Pb alone and as a mixture in an animal model of acute exposure. Methods: Experimental groups received a single treatment of aqueous solution of Cd-chloride (15 and 30 mg/kg body weight (b.w.) and Pb-acetate (150 mg/kg b.w.), while the mixture group received 15 mg Cd/kg b.w. and 150 mg Pb/kg b.w. Toxic effects of individual metals and their mixture were investigated on hematological and biochemical parameters, and the redox status in the plasma, liver, and kidneys of treated Wistar rats. Results: Tissue-specific changes were recorded in various parameters of oxidative damage, while the accumulation of metals in tissues accompanied the disturbances of both hematological and biochemical parameters. It was observed that the level of toxic metals in tissues had a different distribution pattern after mixture and single exposure. Conclusions: Comprehensive observations suggest that exposure to Cd and Pb mixtures produces more pronounced effects compared to the response observed after exposure to single metal solutions. However, further research is needed to confirm toxicokinetic or toxicodynamic interactions between these two toxic metals in the organisms.

Cadmium Exposure as a Putative Risk Factor for the Development of Pancreatic Cancer: Three Different Lines of Evidence

Although profoundly studied, etiology of pancreatic cancer (PC) is still rather scant. Exposure to cadmium (Cd), a ubiquitous metal associated with well-established toxic and carcinogenic properties, has been hypothesized to one putative cause of PC. Hence, we analyzed recently published observational studies, meta-analyses, and experimental animal and in vitro studies with the aim of summarizing the evidence of Cd involvement in PC development and describing the possible mechanisms. Consolidation of epidemiological data on PC and exposure to Cd indicated a significant association with an elevated risk of PC among general population exposed to Cd. Cadmium exposure of laboratory animals was showed to cause PC supporting the findings suggested by human studies. The concordance with human and animal studies is buttressed by in vitro studies, although in vitro data interpretation is problematic. In most instances, only significant effects are reported, and the concentrations of Cd are excessive, which would skew interpretation. Previous reports suggest that oxidative stress, apoptotic changes, and DNA cross-linking and hypermethylation are involved in Cd-mediated carcinogenesis. Undoubtedly, a significant amount of work is still needed to achieve a better understanding of the Cd involvement in pancreatic cancer which could facilitate prevention, diagnosis, and therapy of this fatal disease.