Evaluation of oxidative stress and pro-inflammatory cytokines in occupationally cadmium exposed workers

The impact of high-fat diet consumption and inulin fiber supplementation on anxiety-related behaviors and liver oxidative status in female Wistar rats

BACKGROUND

Obesity is a worldwide public health problem associated with cognitive and mental health problems in both humans and rats. Studies assessing the effect of fiber supplementation on behavioral deficits and oxidative stress caused by high-fat diet (HFD) consumption in female rats are still scarce. We hypothesized that HFD consumption would lead to anxiety-related behavior and hepatic oxidative stress and that inulin would protect against these changes. We analyzed the impact of HFD-induced obesity combined with fiber supplementation (inulin) on anxiety-related defensive behavior and hepatic oxidative stress.

RESULTS

Female rats were fed a high-fat diet (HFD; 45%) for nine weeks to induce obesity. The administration of inulin was found to decrease the adiposity index in both the control and obese groups. The consumption of a HFD combined with inulin supplementation resulted in a reduction in both CAT activity and carbonylated protein levels, leading to a shift in the hepatic redox balance. Interestingly, the behavioral data were conflicting. Specifically, animals that consumed a high-fat diet and received inulin showed signs of impaired learning and memory caused by obesity. The HFD did not impact anxiety-related behaviors in the female rats. However, inulin appears to have an anxiolytic effect, in the ETM, when associated with the HFD. On the other hand, inulin appears to have affected the locomotor activity in the HFD in both open field and light-dark box.

CONCLUSION

Our results show that consumption of a HFD induced obesity in female rats, similar to males. However, HFD consumption did not cause a consistent increase in anxiety-related behaviors in female Wistar rats. Treatment with inulin at the dosage used did not exert consistent changes on the behavior of the animals, but attenuated the abdominal WAT expansion and the hepatic redox imbalance elicited by high-fat diet-induced obesity.

Are lead, cadmium and mercury risk factors for resistant hypertension?

BACKGROUND

Lead (Pb), cadmium (Cd) and mercury (Hg) are toxic trace elements that represent a public health problem as risk factors for cardiovascular disease and hypertension (HT) and could also contribute to the development of resistant hypertension (rHT) AIMS: To compare the blood concentrations of Pb, Cd and Hg in subjects with resistant and non-resistant HT and to define whether there is a relationship between its levels and rHT.

METHODS

Cross-sectional study. Subjects aged ≥ 21 to ≤ 80 years with a body mass index < 40 kg/m2 were recruited on a discretionary basis from October 2001 to October 2004 in a hypertension unit of a tertiary hospital amongst those sent to the hypertension unit by their family physician. Resistant hypertension was defined according to the American Heart Association (AHA) criteria. Whole blood concentrations of Cd, Pb and Hg were measured by electrothermal atomic absorption spectrometry.

RESULTS

46 out of 73 included subjects (63%) suffered from rHT. Blood Pb median: HT 3.9 (IQR 2.7-5.2) vs. rHT 3.6 (IQR 2.8-6.0) µg/dL (p=0.941). Blood Cd median: HT 0.07 (IQR 0.07-0.80) vs. rHT 0.30 (IQR 0.07-0.65) µg/L (p=0.681). Blood Hg median: HT 7.9 (IQR 5.8-12.9) vs. rHT 7.3 (IQR 4.6-13.3) µg/L (p=0.611). Considering the 75th percentile of each element (Pb: 5.55 µg/dL, Cd: 0.75 µg/L, Hg: 13.15 µg/L), a multiple logistic regression analysis (adjusted for age, BMI, diabetes mellitus, clearance of creatinine and only for Cd the smoking habit) showed an OR = 3.44 (0.84-14.10, p=0.086) for Pb, OR = 1.80 (0.39-8.24, p=0.451), for Cd and OR = 2.31 (0.59-9.14, p=0.232) for Hg. Moreover, the stratified analyses showed that men with Pb ≥5.55 µg/dL have a 14 times higher risk of suffering from rHT (p=0.026). Interestingly, a 9-fold increased risk was found for non-obese subjects with elevated Pb levels, above 5.55 µg/dL (p=0.029). Also in men, the probability of suffering from rHT was more than 7 times higher if Cd levels were ≥ 0.75 µg/L (p=0.076). Most smokers had higher Cd levels, with a high risk of suffering from rHT (ORa 12.6 (0.8-200.2), p=0.072).

CONCLUSION

A higher blood Pb levels, defined by the 75th percentile (Pb ≥ 5.55 µg/dL), is associated with a greater risk of suffering from rHT and to a lesser extent in the case of Cd and Hg.

Orally Administrated Lactiplantibacillus plantarum BGAN8-Derived EPS-AN8 Ameliorates Cd Hazards in Rats

Cadmium (Cd) is a highly toxic metal that is distributed worldwide. Exposure to it is correlated with a vast number of diseases and organism malfunctions. Exopolysaccharides (EPS) derived from Lactiplantibacillus plantarum BGAN8, EPS-AN8, previously showed great potential for the in vitro protection of intestinal cells from this metal. Here, we investigated the potential of food supplemented with EPS-AN8 to protect rats from the hazardous effects of Cd exposure. After thirty days of exposure to lower (5 ppm) and higher (50 ppm)-Cd doses, the administration of EPS-AN8 led to decreased Cd content in the kidneys, liver, and blood compared to only Cd-treated groups, whereas the fecal Cd content was strongly enriched. In addition, EPS-AN8 reversed Cd-provoked effects on the most significant parameters of oxidative stress (MDA, CAT, GST, and GSH) and inflammation (IL-1β, TNF-α, and IFN-γ) in the duodenum. Moreover, micrographs of the duodenum were in line with these findings. As the gut microbiota has an important role in maintaining homeostasis, we used 16S rRNA amplicon sequencing and investigated the effects of Cd and EPS-AN8 on one part of the microbiota presented in the duodenum. Although Cd decreased the growth of lactobacilli and mostly favored the blooming of opportunistic pathogen bacteria, parallel intake of EPS-AN8 reversed those changes. Therefore, our results imply that EPS-AN8 might be extremely noteworthy in combatting this toxic environmental pollutant.

Plasma microRNA expression and immunoregulatory cytokines in an Indian population occupationally exposed to cadmium

Following its accumulation in the body, cadmium (Cd) exposure is associated with devastating effects on multiple organ system of the human body. The immune system is one of the sensitive targets for Cd-induced toxicity. Recently, studies have demonstrated a significant role of Cd in inducing epigenetic alterations. With this background, the present study was planned to study the changes in candidate microRNA (miRNA) expression associated with immune regulation in occupationally Cd-exposed workers. One hundred individuals involved in welding and metal handicraft manufacturing, while 80 apparently healthy subjects without any prior history of occupational exposure were recruited for the study. Blood Cd level was determined by atomic absorption spectrometry. Serum cytokine levels were measured using an enzyme-linked immunosorbent assay and serum miRNA expression of candidate miRNAs (miR-146a, miR-210, and miR-222) were determined by real-time polymerase chain reaction. The median Cd level (2.40 μg/L) in the occupationally exposed workers was significantly higher than the nonexposed subjects (0.90 μg/L). Among the cytokines, interleukin-4 (IL-4), and tumor necrosis factor-alpha (TNF-α) were significantly higher while IL-2 and IL-10 were significantly lower in the exposed. The expression level of miR-146a and miR-222 were significantly different between the groups with the former showing downregulation and later showing upregulation. Correlation analysis revealed a positive and negative association of miR-222 and miR-146a with blood cadmium level, IL-17 as well as TNF-α, respectively. Furthermore, the in-silico analysis revealed a significant role of the studied miRNAs in various cellular and genetic pathways. The findings of the present study demonstrate significant involvement of Cd-induced alteration in miRNAs in varied immune regulatory changes in exposed individuals.

Individual and mixtures of metal exposures in associations with biomarkers of oxidative stress and global DNA methylation among pregnant women

BACKGROUND

Prenatal exposure to metals has been linked with adverse pregnancy outcomes. Oxidative stress and epigenetic changes are potential mechanisms of action.

OBJECTIVES

We aimed to examine the associations of individual and mixtures of metal exposures with oxidative stress and DNA methylation among pregnant women.

METHODS

We measured a panel of 16 metals and 3 oxidative stress biomarkers including 8-hydroxydeoxyguanosine (8-OHdG), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA) and 8-isoprostaglandin F2α (8-isoPGF2α) in urine from 113 pregnant women in a Chinese cohort. Biomarkers of global DNA methylation including Alu and long interspersed nucleotide element-1 (LINE-1) in cord blood were measured. Multivariable linear regression and Bayesian kernel machine regression (BKMR) models were separately applied to estimate the associations between individual and mixtures of metal exposures and biomarkers of oxidative stress and global DNA methylation.

RESULTS

In single-metal analyses, we observed positive associations between 11 metals [arsenic (As), cadmium (Cd), thallium (Tl), barium (Ba), nickel (Ni), vanadium (V), cobalt (Co), zinc (Zn), copper (Cu), selenium (Se) and molybdenum (Mo)] and at least one of oxidative stress biomarkers (all FDR-adjusted P-values < 0.05). In mixture analyses, we found positive overall associations of metal mixtures with 8-OHdG and 8-isoPGF2α, and Se was the most important predictor. There was no evidence on associations of urinary metals as individual chemicals and mixtures with Alu and LINE-1 methylation.

CONCLUSION

Urinary metals as individual chemicals and mixtures were associated with increased oxidative stress, especially Se.

Cadmium Body Burden and Inflammatory Arthritis: A Pilot Study in Patients from Lower Silesia, Poland

The purpose of this study was to determine the relationship between cadmium exposure and the likelihood of developing or exacerbating symptoms of inflammatory arthritis (IA). The study included 51 IA patients and 46 control subjects. Demographic and lifestyle data were collected. Haematological and biochemical parameters and blood cadmium levels (Cd-B) were determined. Cd-B correlated positively with age, smoking, living in a high-traffic area, and serum levels of inflammatory markers and negatively with mean corpuscular haemoglobin concentration (MCHC). The binary logistic regression model implied that high Cd-B (≥0.65 μg/L) is linked with an increased risk of IA in the studied population (odds ratio: 4.4). High levels of DNA oxidative damage marker (8-hydroxy-2’-deoxyguanosine) (≥7.66 ng/mL) and cyclooxygenase-2 (≥22.9 ng/mL) and frequent consumption of offal was also associated with increased risk of IA. High Cd-B was related to increased risk of disease symptoms onset in the group of IA patients, decreased the level of interleukin 10, and positively correlated with the disease activity. Increased Cd-B is associated with intensified inflammatory processes and decreased haemoglobin levels; in IA patients with decreased anti-inflammatory interleukin 10. These changes partly explain why cadmium exposure and a high cadmium body burden may raise the risk of IA and of disease symptoms exacerbation.

Association between lead and cadmium co-exposure and systemic immune inflammation in residents living near a mining and smelting area in NW China

Exposure to both cadmium (Cd) and lead (Pb) can promote systemic inflammation. However, the effects of combined exposure to environmental levels of Cd and Pb on systemic immune inflammation have not been fully clarified. A total of 486 subjects (313 women and 173 men) living in either a control area or heavy metal-polluted area were included. Blood Cd and Pb and immune inflammation biomarkers were determined, including the eosinophil-lymphocyte ratio (ELR), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), lymphocyte-monocyte ratio (LMR), and systemic immune-inflammation index (SII); moreover, the associations between exposure markers and systemic inflammation markers were analysed. The exposure levels in the polluted area were significantly higher than those in the control area. The NLR, PLR, and SII of subjects in the polluted area were higher and the LMR was lower than in the control area. Blood Pb and Cd levels are associated with elevated or decreased immune inflammation biomarkers in subjects from the exposed and control areas. Furthermore, co-exposure to both Cd and Pb was divided into high, middle, and low exposure groups. The subjects in the high co-exposure group displayed higher levels of ELR, NLR, and SII compared with the middle and low co-exposure group, and LMR levels displayed the opposite trend. Our data demonstrate that Cd and Pb co-exposure is associated with systemic immune inflammation, and the immune inflammatory response is aggravated with an increased co-exposure to Cd and Pb.