Alterations in trace elements and oxidative stress in uremic patients with dementia

Trace Elements Status and Their Associations With Related Antioxidant Enzyme Activities in Patients Receiving Peritoneal Dialysis and Hemodialysis

OBJECTIVE

It remains ambiguous as to whether the status of trace elements would affect their related enzyme activities toward defending a possible higher oxidative stress in patients receiving peritoneal dialysis (PD) or hemodialysis (HD) treatment. We investigated copper (Cu), zinc (Zn), and selenium (Se) status in patients receiving PD or HD treatments and further determined the association of these trace elements with their related antioxidant capacities in those patients.

METHODS

Sixty PD and 80 HD patients before and after HD treatment had their blood drawn. Demographic, clinical, and 24-hour diet recall data were recorded and collected. Plasma trace elements, oxidative stress indicators, and antioxidant enzyme activities were measured.

RESULTS

Patients receiving PD or HD treatments experienced similar Zn and Cu intakes. PD and HD patients displayed adequate mean plasma Cu, Zn, and Se levels. Patients receiving PD treatment showed significantly higher levels of Cu, Zn, advanced oxidation protein products (AOPPs), and superoxide dismutase (SOD) activity, but had significantly lower levels of Se and total antioxidant capacity when compared to levels in the HD patients at the pre-HD session. The levels of 3 trace elements and AOPP increased significantly, while the levels of glutathione (GSH), oxidized glutathione (GSSG), GPx, and SOD activities decreased significantly after receiving HD treatment than did the levels in the pre-HD session. Plasma Cu, Se, and Zn levels had a different correlation with plasma AOPP level, GPx, and SOD activities during PD, pre- or post-HD sessions. Plasma Cu, Zn, and Se levels did not have any association with their associated enzyme activities in patients with PD, while plasma Cu and Zn levels may have influenced SOD activity in HD patients.

CONCLUSIONS

An adequate Cu, Zn, and Se status is required in order to help their associated enzyme activity cope with increased oxidative stress during PD or HD sessions.

Detection of Cu2+ and S2- with fluorescent polymer nanoparticles and bioimaging in HeLa cells

Novel spherical polymer nanoparticles were synthesized by hyperbranched polyethylenimine (hPEI) and 6-hydroxy-2-naphthaldehyde (HNA) via Schiff base reaction (one-pot reaction), which had great advantages in water solubility and green synthesis. Meanwhile, probe PEI-HNA could quickly detect Cu²⁺ in the range of 0-60 μM in 30 s with the detection limit of 243 nM. The fluorescence of PEI-HNA-Cu²⁺ could be recovered by the addition of S^2- in 50 s with the detection limit of 227 nM. Based on the excellent optical properties, PEI-HNA has been used in the bioimaging of living cells with excellent cell penetrability and low toxicity. More importantly, PEI-HNA has been doped into filter paper, hydrogel, and nanofibrous film to prepare solid-phase sensors, displaying rapid response and excellent sensitivity. Moreover, the low-cost and simple preparation of these sensors offers great potential and possibilities for industrialization, which could help accelerate the development of sensors in environmental and biological fields.

The Effect of Aluminum Exposure on Reproductive Ability in the Bank Vole (Myodes glareolus)

Human impact on the environment is steadily increasing the amounts of aluminum in the ecosystems. This element accumulates in plants and water, potentially exposing herbivores to its harmful effect. In heavily polluted sites, a decrease in the density of small rodent populations has been observed. This decline may be caused by many factors, including decreased fertility. The aim of the presented research was to determine how aluminum, administered at concentrations similar to those recorded in industrial districts (Al I = 3 mg/l, Al II = 200 mg/l), affects the reproductive abilities of small rodents. As the indicators of reproductive abilities, body weight, weight of the testes and accessory sex glands of males, and uterus weight of females were estimated. In females, the number of matured follicles (types 6, 7, and 8) was analyzed, while in males, the quantity and quality (matured, viable, swollen, motile, head abnormalities) of epididymal sperm cells were assessed. Moreover, the development of testes, measured by spermatogenic index, was determined. The model species was the bank vole. Our results have proven that aluminum impairs adult individuals' reproductive abilities by decreasing the quality and quantity of sperm cells and by causing morphologically abnormal development of the gonads. However, no difference in male organometric parameters was found, and only in females treated with 3 mg/l Al, the uterus weight was higher than control. No differences were found in the total number of matured follicles. These results suggest that the decline in rodent numbers in industrial districts is due, at least in part, to poorer males' reproductive abilities, resulting from exposure to aluminum contamination.

Impact of dialyzer membrane flux on metal clearance in hemodialysis patients

Deficiency of essential trace elements (such as Cu or Zn) and accumulation of potentially toxic trace elements (as Cd or Pb) are both known to have adverse effects in hemodialysis (HD) patients. Up to our knowledge, no studies about the permeability of low and high flux polysulfone membranes on metal ions during hemodialysis are available. Therefore, the aim of the present study was to address this issue. Forty one hemodialysis patients (19 were using high flux polysulfone membrane while the remaining were using low flux one) participated in the study. Blood levels of Cu, Zn, Cd and Pb were determined by graphite furnace atomic absorption spectrometry among HD patients, before and after dialysis session, as well as among matched 40 healthy persons. Blood concentrations of Cu and Zn in the whole hemodialysis group was significantly lower than those of the healthy control group, on the other hand the toxic metals (Cd and Pb) levels were observed to be significantly higher among HD patients compared to the normal persons. Among the hemodialysis group, there were no significant differences between the low and high flux dialyzer groups in terms of pre-dialysis blood levels of Cu, Zn, Cd and Pb. In addition, significantly decreased levels of all metal ions were observed after dialysis sessions using either low or high flux membranes. An exception was Pb which did not show any difference between pre-dialysis and post-dialysis values in the low flux groupIn conclusion Zn and Cu deficiencies should be considered in the treatment of these patients. High flux membranes are more efficient than low flux ones in removing excess Cd and Pb. Therefore, when high flux membranes are used, chelation therapy might not be required for Cd and Pb overload.

[The degree of chronic renal failure is associated with the rate of pro-inflammatory cytokines, hyperhomocysteinemia and with oxidative stress]

AIM

To evaluate pro-inflammatory cytokines, homocysteinemia and markers of oxidative status in the course of chronic renal failure.

PATIENTS AND METHODS

One hundred and two patients (male/female: 38/64; age: 45±07 years) with chronic renal failure were divided into 4 groups according to the National Kidney Foundation classification. They included 28 primary stage renal failure patients, 28 moderate stage renal failure, 28 severe stage renal failure and 18 end stage renal failure. The inflammatory status was evaluated by the determination of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-6) and total homocysteine. Pro-oxidant status was assessed by assaying thiobarbituric acid reactive substances, hydroperoxides, and protein carbonyls. Antioxidant defence was performed by analysis of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase.

RESULTS

Inflammatory markers were elevated in the end stage renal failure group compared to the other groups (P<0.001). Indeed, an increase in thiobarbituric acid reactive substances, hydroperoxides and protein carbonyls was noted in the end stage renal failure group in comparison with the other groups (P<0.001), while the levels of antioxidants enzymes activity were decreased in the study population (P<0.001).

CONCLUSION

Impaired renal function is closely associated with the elevation of inflammatory markers leading to both increased markers of oxidative stress and decreased antioxidant defense.

Effect of different stages of chronic kidney disease and renal replacement therapies on oxidant-antioxidant balance in uremic patients

Oxidative stress seems to be involved in the path physiology of cardiovascular complications of chronic kidney disease (CKD). In this study, we determined the effect of different stages of CKD and substitutive therapies on oxidative stress. One hundred sixty-seven patients (age: 44 ± 06 years; male/female: 76/91) with CKD were divided into 6 groups according to the National Kidney Foundation classification. Prooxidant status was assessed by assaying thiobarbituric acid reactive substances, hydroperoxides, and protein carbonyls. Antioxidant defence was performed by analysis of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, vitamin E, Iron, and bilirubin. TBARS and LPO were higher in HD patients compared to other groups (P < 0.001), while protein carbonyls were more increased in PD patients. The antioxidant enzymes were declined already at severe stage of CKD and they were declined notably in HD patients (P < 0.001). Similar observation was found for vitamin E, Fe, and bilirubin where we observed a significant decrease in the majority of study groups, especially in HD patients (P < 0.001). The evolution of CKD was associated with elevated OS. HD accentuates lipid, while PD aggravates protein oxidation. However, the activity of antioxidant enzymes was altered by impaired renal function and by both dialysis treatments.

In Vivo Effect of Arsenic Trioxide on Keap1-p62-Nrf2 Signaling Pathway in Mouse Liver: Expression of Antioxidant Responsive Element-Driven Genes Related to Glutathione Metabolism

Arsenic is a Group I human carcinogen, and chronic arsenic exposure through drinking water is a major threat to human population. Liver is one of the major organs for the detoxification of arsenic. The present study was carried out in mice in vivo after arsenic treatment through drinking water at different doses and time of exposure. Arsenic toxicity is found to be mediated by reactive oxygen species. Nuclear factor (erythroid-2 related) factor 2 (Nrf2)/Keap1 (Kelch-like ECH-associated protein 1)/ARE (antioxidant response element)-driven target gene system protects cells against oxidative stress and maintains cellular oxidative homeostasis. Our result showed 0.4 ppm, 2 ppm, and 4 ppm arsenic trioxide treatment through drinking water for 30 days and 90 days induced damages in the liver of Swiss albino mice as evidenced by histopathology, disturbances in liver function, induction of heat shock protein 70, modulation of trace elements, alteration in reduced glutathione level, glutathione-s-transferase and catalase activity, malondialdehyde production, and induction of apoptosis. Cellular Nrf2 protein level and mRNA level increased in all treatment groups. Keap1 protein as well as mRNA level decreased concomitantly in arsenic treated mice. Our study clearly indicates the important role of Nrf2 in activating ARE driven genes related to GSH metabolic pathway and also the adaptive response mechanisms in arsenic induced hepatotoxicity.

Clinical factors associated with serum copper levels and potential effect of sevelamer in hemodialysis patients

OBJECTIVE

Copper is an essential mineral nutrient for humans. Serum copper levels of hemodialysis patients are higher than those of healthy subjects, but it remains to be elucidated whether increased serum copper may have harmful effects. In addition, a recent in vitro study has shown that sevelamer can adsorb copper. In the present study, we searched for clinical factors associated with serum copper levels in hemodialysis patients.

METHODS

This cross-sectional study included patients undergoing hemodialysis for more than 6 months. In these patients, we statistically tested associations between serum copper levels and other parameters, including nutritional markers, lipid profiles, oxidative stress, inflammation, and sevelamer administration.

RESULTS

Among 48 patients (male/female = 28:20, age 71 ± 10 years, hemodialysis duration 84 ± 72 months), sevelamer hydrochloride was administered in 39 patients (81.3 %). In univariate analysis, serum copper levels showed significant positive correlations with serum levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, high-sensitivity C-reactive protein (hs-CRP), and malondialdehyde modified-LDL and negative correlations with plasma total homocysteine levels and the administered dose of sevelamer. In multivariate analysis, serum levels of LDL-cholesterol and hs-CRP were found to be independent determinants of serum copper levels.

CONCLUSION

We found that serum copper levels were independently associated with dyslipidemia and inflammation in hemodialysis patients, but the pathogenic roles of copper remain to be elucidated. In addition, potential effect of sevelamer on serum copper levels should be examined in appropriately designed studies.

Trace metal imbalance associated with oxidative stress and inflammatory status in anti-hepatitis C virus antibody positive subjects

Toxic and essential trace metals, oxidative stress, and inflammatory status were evaluated in anti-hepatitis C virus (HCV) antibody-positive subjects. Blood biochemical parameters were determined in anti-HCV antibody-positive (n=17) and -negative controls (n=46). Compared with controls, anti-HCV antibody-positive individuals had significantly lower concentrations of plasma zinc (Zn); higher copper (Cu), iron (Fe), lead (Pb), cadmium (Cd), and aluminum (Al); and lower activities of erythrocyte antioxidant enzymes glutathione peroxidase and catalase, and elevated superoxide dismutase. Significantly increased lipid peroxidation malondialdehyde (MDA), and inflammatory markers such as alanine aminotransferase (ALT), high sensitivity C-reactive protein (hs-CRP), ferritin, and Cu/Zn ratios, as well as decreased albumin and high density lipoprotein (HDL) concentrations were observed. We have found significant interactions between toxic (e.g., Pb, Cd, and Al) and essential metals (e.g., Zn, Cu, Fe), which correlated with MDA. In conclusion, anti-HCV antibody-positive subjects had abnormal distributions of trace metals that may aggravate oxidative stress and inflammation, and exacerbate hepatic damage.

Cu/Zn ratios are associated with nutritional status, oxidative stress, inflammation, and immune abnormalities in patients on peritoneal dialysis

OBJECTIVES

We evaluated the relationship of the plasma copper/zinc (Cu/Zn) ratio with nutritional status, inflammation, oxidative stress, and immune function in peritoneal dialysis patients.

DESIGN AND METHODS

Clinical and laboratory parameters were measured in patients (n=45) and age- and sex-matched healthy individuals (n=30).

RESULTS

There were significant negative correlations of the Cu/Zn ratio with nutrition-related parameters (body mass index [BMI], creatinine, hemoglobin, and albumin) and antioxidant (vitamin C and E) levels and positive correlations of the Cu/Zn ratio with the levels of high sensitivity C-reactive protein (hs-CRP) and oxidation products (malondialdehyde [MDA] and protein carbonyl). The Cu/Zn ratio was negatively correlated with the percentages of B- and T-lymphocyte subsets and the ratio of CD4/CD8 antigens.

CONCLUSIONS

In peritoneal dialysis patients, elevated Cu/Zn ratios are associated with malnutrition, increased oxidative stress, inflammation, and disrupted immune status.

Linkage of some trace elements, peripheral blood lymphocytes, inflammation, and oxidative stress in patients undergoing either hemodialysis or peritoneal dialysis

BACKGROUND

Changes in essential trace elements may affect the inflammatory and immunological state of patients on hemodialysis (HD) or peritoneal dialysis (PD). Therefore, we aimed to determine trace element content and markers of oxidative stress, inflammation, and immune status in HD and PD patients and to assess the relationships among these parameters.

METHODS

Patients on either HD (n = 20) or PD (n = 20) and age-, sex-, body mass index-matched healthy individuals (n = 20) were enrolled in the study. The trace elements zinc, copper, selenium, and iron; markers of oxidative stress thiobarbituric acid reactive substances (TBARS) and protein carbonyl levels; activities of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase; percentages of CD3 T lymphocytes and the subsets CD4 and CD8; the CD4/CD8 ratio; and C-reactive protein (CRP) were measured.

RESULTS

All dialysis patients had low levels of albumin and hemoglobin. Significantly decreased percentages of CD3 and CD4 T lymphocytes and increased levels of CRP, TBARS, and carbonyl compounds were observed in HD patients. HD patients also had elevated erythrocyte SOD, lower GPx and catalase activities, and decreased levels of Se, Zn, and Fe in comparison to PD patients and healthy subjects. In addition, CRP was positively associated with TBARS and carbonyl levels, but was significantly inversely associated with Zn and Se levels. Positive correlations were found between T lymphocyte CD3 and CD4 percentages and Zn, Se, and Fe levels.

CONCLUSIONS

There were significant decreases in T lymphocyte-related immunological regulation and increased inflammation and oxidative stress in dialysis patients. Essential trace element status was independently related to immune status, inflammation, and oxidative damage.