Carvedilol induces the antiapoptotic proteins Nrf2 and Bcl2 and inhibits cellular apoptosis in aluminum-induced testicular toxicity in male Wistar rats

The present study was carried out to explore the protective effect of carvedilol (CARV) on aluminum chloride-induced testicular damage in Westar rats. Forty adult male rats, aged 8 weeks, were randomly divided into 4 groups (10 rats each). Group I (control group) received normal saline; whereas group II animals were supplemented with CARV in a dose of 10 mg/kg/day. Group III received AlCl3 (30 mg/kg/day) whereas group IV was co-administered CARV and AlCl3 as the same doses in group II and III respectively. The route of the application was oral gavage for CARV and I.P for AlCl3 for 20 successive days. Exposure of rats to AlCl3 for 20 consecutive days resulted in a significant decrease in serum and testicular superoxide dismutase and catalase activities, serum testosterone level, and sperm count and motility; on the other hand, an increase in nitric oxide, malondialdehyde, aluminum, and serum tumor necrosis factor-alpha levels. Furthermore, histopathological changes in the testis exhibited marked testicular damage. In addition, it revealed a significant up-regulation in the level of the expression for the apoptotic marker; Caspase-3, and down-regulation in antiapoptotic marker Bcl2 and Nrf2 genes. On the other hand, the co-administration of CARV modulated the biochemical parameters, saved sperm count and motility, and the histopathological findings, also, restored the observed changes in Caspase-3, Bcl2, and Nrf2 transcriptional genes. These data suggested that administration of CARV protects against AlCl3 induced testicular oxidative, inflammatory, and apoptosis damage.

Cross-sectional study based on occupational aluminium exposure population

To evaluate the different characteristics of cognitive impairment caused by occupational aluminium exposure at different ages, we surveyed 1660 workers in Shanxi Aluminium Plant, China, and assessed their cognitive function and plasma aluminium concentration. In multiple linear regression, the scores of the digit-span test (DST) and digit-span backward test (DSBT) were negatively correlated with plasma aluminium concentration when concentration reached 34.52 μg/L in younger group (＜40 years), while in the middle-aged group (≥40 years) only found when concentration reached 42.25 μg/L (β<0, P < 0.05). In logistic regression, when plasma aluminum concentration reached 42.25μg/L, odds ratios (95 % confidence interval) were 1.695 (1.062-2.705) and 3.270 (1.615-6.620) for DST, 7.644 (3.846-15.192) and 15.308 (4.180-56.059) for DSBT in middle-aged group and younger group, respectively. These results showed that aluminium exposures were associated with cognitive impairment among aluminium-exposed workers, particularly for young workers who were more susceptible.

Aluminum and magnesium status during pregnancy and placenta oxidative stress and inflammatory mRNA expression: China Ma'anshan birth cohort study

The aim of this study was to explore the impact of prenatal Al and Mg on placental oxidative stress and inflammatory mRNA expression. A total of 2519 pregnant women from the China Ma'anshan birth cohort participated in this study. Al and Mg levels were measured by inductively coupled plasma mass spectrometry (ICP-MS). Placental stress and inflammatory mRNA expression were assessed by RT-PCR. The median Al levels in the first and second trimesters of pregnancy and in cord blood were higher than the corresponding median Mg levels. Predictors of lower Al and Mg levels included Han ethnicity and high education according to a mixed linear model. Multiple linear regression analysis revealed that Al and Al/Mg levels had a positive association with inflammatory mRNA expression and placental oxidative stress in the second trimester of pregnancy. A negative association existed between Al and Al/Mg levels and inflammatory mRNA expression and placenta oxidative stress in the cord blood, with the exception of IL-1β expression. In conclusion, prenatal Al and Mg status was associated with placental oxidative stress and inflammatory mRNA expression. More preclinical studies are needed to confirm the relevant mechanism.

Renal osteodystrophy and clinical outcomes: data from the Brazilian Registry of Bone Biopsies - REBRABO

INTRODUCTION

Mineral and bone disorders (MBD) are major complications of chronic kidney disease (CKD)-related adverse outcomes. The Brazilian Registry of Bone Biopsy (REBRABO) is an electronic database that includes renal osteodystrophy (RO) data. We aimed to describe the epidemiological profile of RO in a sample of CKD-MBD Brazilian patients and understand its relationship with outcomes.

METHODS

Between August 2015 and March 2018, 260 CKD-MBD stage 3-5D patients who underwent bone biopsy were followed for 12 to 30 months. Clinical-demographic, laboratory, and histological data were analyzed. Bone fractures, hospitalizations, and death were considered the primary outcomes.

RESULTS

Osteitis fibrosa, mixed uremic osteodystrophy, adynamic bone disease, osteomalacia, osteoporosis, and aluminum (Al) accumulation were detected in 85, 43, 27, 10, 77, and 65 patients, respectively. The logistic regression showed that dialysis vintage was an independent predictor of osteoporosis (OR: 1.005; CI: 1.001-1.010; p = 0.01). The multivariate logistic regression revealed that hemodialysis treatment (OR: 11.24; CI: 1.227-100; p = 0.03), previous parathyroidectomy (OR: 4.97; CI: 1.422-17.241; p = 0.01), and female gender (OR: 2.88; CI: 1.080-7.679; p = 0.03) were independent predictors of Al accumulation; 115 patients were followed for 21 ± 5 months. There were 56 hospitalizations, 14 deaths, and 7 fractures during follow-up. The COX regression revealed that none of the variable related to the RO/turnover, mineralization and volume (TMV) classification was an independent predictor of the outcomes.

CONCLUSION

Hospitalization or death was not influenced by the type of RO, Al accumulation, or TMV classification. An elevated prevalence of osteoporosis and Al accumulation was detected.

Aluminium levels in hair and urine are associated with overweight and obesity in a non-occupationally exposed population

BACKGROUND

Data on the association between aluminium (Al) exposure and obesity and/or metabolic syndrome are insufficient. The objective of the present study was to investigate the association between hair and urine Al levels and obesity.

METHODS

A total of 206 lean and 205 obese non-occupationally exposed subjects (30-50 y.o.) were enrolled in the study. Hair and urine Al levels were assessed with ICP-MS. Laboratory quality control was performed using the certified reference materials of human hair, plasma, and urine.

RESULTS

Hair and urinary Al levels in obese subjects were significantly higher by 31% and 46% compared to the control levels, respectively. The presence of hypertension (41% cases), atherosclerosis (8%), type 2 diabetes mellitus (10%), and non-alcoholic fatty liver disease (NAFLD) (53%) in obese patients were not associated with Al levels in the studied subjects. An overall multiple regression model established urinary Al levels (β = 0.395; p < 0.001), hypertension (β = 0.331; p < 0.001) and NAFLD (β = 0.257; p = 0.003) were significantly and directly associated with BMI. Hair Al levels were found to be border-line significantly related to BMI after adjustment for several confounders (β = -0.205; p = 0.054).

CONCLUSIONS

Aluminium body burden is associated with increased body weight, although the causal relationship between Al exposure and obesity is not clear. Both clinical and experimental studies are required to further investigate the impact of Al exposure on metabolic parameters in obesity and especially direct effects of Al in adipose tissue.

Association Between Exposure to Heavy Metals and Systemic Sclerosis: the Levels of Al, Cd, Hg, and Pb in Blood and Urine of Patients

Systemic sclerosis (SSc) is a multisystem connective tissue disease; exogenous factors-including heavy metals-may have a role in the disease pathogenesis. In this context, a study on the quantification of Al, Cd, Hg, and Pb in blood and urine of 27 SSc patients and 30 controls was carried out. Main findings were that Al was significantly depleted in blood and increased in urine of SSc patients respect to controls; and Pb was found slightly increased in blood and significantly decreased in SSc group. In addition, higher Hg levels in urine were found in SSc subjects with the higher severity of the disease. Females showed the most marked differences in the levels of blood Al, blood Pb, and urine Cd between patients and controls. Smoking, hobby, ingestion of contaminated food, job exposure may contribute to the bodily levels of Al, Hg, Pb in SSc patients. The results indicated that low, chronic, and multiple exposures to heavy metals-also through habits, diet, and environment-may influence the risk for SSc.

Concentrations of Lead, Mercury, Arsenic, Cadmium, Manganese, and Aluminum in Blood of Romanian Children Suspected of Having Autism Spectrum Disorder

Environmental exposure to lead (Pb), mercury (Hg), arsenic (As), cadmium (Cd), manganese (Mn), and aluminum (Al) has been associated with neurodevelopmental disorders including autism spectrum disorder (ASD). We conducted a pilot study during May 2015-May 2107 to estimate blood concentrations of six metals (Pb, Hg, As, Cd, Mn, and Al) and identify their associated factors for children with ASD or suspected of having ASD in Romania. Sixty children, age 2-8 years, were administered versions of ADOS or ADI-R translated from English to Romanian. After assessment, 2-3 mL of blood was obtained and analyzed for the concentrations of the six metals. The mean age of children was 51.9 months and about 90% were male. More than half (65%) of the children were born in Bucharest. Over 90% of concentrations of As and Cd were below limits of detection. Geometric mean concentrations of Pb, Mn, Al, and Hg were 1.14 μg/dL, 10.84 μg/L, 14.44 μg/L, and 0.35 μg/L, respectively. Multivariable linear regression analysis revealed that children who were female, had less educated parents, exhibited pica, and ate cold breakfast (e.g., cereal), watermelon, and lamb had significantly higher concentrations of Pb compared to their respective referent categories (all p < 0.05 except for eating lamb, which was marginally significant, p = 0.053). Although this is the first study that provides data on concentrations of the six metals for Romanian children with ASD, the findings from this study could be useful for designing future epidemiologic studies for investigating the role of these six metals in ASD in Romanian children.

Cognitive impairment of workers in a large-scale aluminium factory in China: a cross-sectional study

OBJECTIVES

To investigate the prevalence of mild cognitive impairment and the relationship with plasma aluminium among aluminium workers.

DESIGN

This was a cross-sectional case-control study in the SH Aluminium Factory, China.

SETTING

The university and affiliated hospital cooperated in the study.

PARTICIPANTS

There were 910 aluminium workers on duty, among whom 853 participated in our study. Participants, such as those with cerebral vascular disease, epilepsy, brain trauma, Parkinson's and mental diseases, aluminium-containing drug and mental drug use, and any family history of dementia in first-degree relatives were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

Blood samples were collected, and plasma aluminium was measured by inductively coupled plasma-mass spectrometry. For each case, four age-matched controls were evaluated to determine the relationship between aluminium exposure and mild cognitive impairment. Conditional logistic regression was used to explore influential factors in mild cognitive impairment.

RESULTS

Among 910 workers, 93.74% participated in stage 1; 53 cases were finally diagnosed. The crude prevalence of mild cognitive impairment among aluminium workers on duty was 6.21%. There was a significant difference in plasma aluminium concentration between the two groups. In the multivariate analysis, we found that a higher level of plasma aluminium was associated with a high risk of cognitive impairment when compared with a lower aluminium level (AOR=2.24, 95% CI=1.17 to 4.26), and a high education level was a protective factor (AOR=0.36, 95% CI=0.18 to 0.70). No other factor was statistically significant.

CONCLUSIONS

Mild cognitive impairment is no longer a disease specific to elderly people. High plasma aluminium exposure might be associated with an increased risk of cognitive impairment, but a reduced risk was observed with a high education level. The cognitive function of aluminium workers on duty must be considered seriously.

Evaluation of Some Trace Elements and Vitamins in Major Depressive Disorder Patients: a Case-Control Study

Major depressive disorder (MDD) is a common mental disorder worldwide; however, little is known about its etiology. It is well known that levels of certain trace elements are associated with the pathogenesis of some diseases. Accordingly, this study aims to evaluate the effect of trace elements and vitamins in the etiology of MDD. In this case-control study, sixty men patients with MDD and sixty, age and gender matched, control subjects were examined. Serum levels of Cu, Zn, Ni, Cr, Mn, Mg, and Al were determined by atomic absorption spectrometry as well as serum levels of vitamins E and A were determined using high-performance liquid chromatography. The results revealed that there were significantly higher levels (p < 0.001) of Cu, Cr, and Al in patients sera compared with control. While there were significantly lower levels (p < 0.001) of Zn, Ni, Mn, Mg, vitamin E, and vitamin A in MDD patients as compared with control. In addition, high Cu/Zn ratio (p < 0.05) was observed with the depressive disorder patients. The present study highlights some main indications: a significant relationship between the disturbances of element levels and vitamins (E and A) with MDD. Cu and Zn seemed to have a crucial role in understanding the pathogenesis of depressive disorders, where Cu/Zn ratio could have an important role in the diagnosis and monitoring of MDD. Moreover, the results suggest that the reduction in the antioxidant vitamin E leads to increased risk of MDD. Finally, more studies on using trace element supplementation would be suggested to clarify their effect, in order to improve the therapy of MDD.

Prevalence and Factors Associated with High Levels of Aluminum, Arsenic, Cadmium, Lead, and Mercury in Hair Samples of Well-Nourished Thai Children in Bangkok and Perimeters

Toxic element exposure increases risk of neurodevelopmental disorders. However, hair element profiles of well-nourished urban resident children were largely unknown. We identified prevalence and the contributing factors of high hair aluminum (Al), arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) levels in 111 Thai children (aged 3-7 years old). Most participants were well-nourished with high socioeconomic status. Since ROC curve of hair element data showed inadequate sensitivity for cutoff set-up, US reference hair levels were used to categorize high and low level groups. Nevertheless, compared to the current reference at 5 μg/dL, blood lead cutoff at 2.15 μg/dL provided more consistent results with that of hair lead levels. High As and Pb levels were the first and second most prevalent element, while Al was the element found in highest amount in hair. High hair Al (12% prevalence) levels were associated with being male regardless of age or nutritional status. High hair As levels were associated with living in Bangkok (OR = 6.57) regardless of school type. High hair Pb levels were associated with being under 5 years old and living in Bangkok (OR = 3.06). However, no associations were found between blood Pb, hair Cd, Hg, and tested factors. These findings suggested that under 5-year-old boys living in capital city like Bangkok may be at risk of exposure to multiple toxic elements. Future studies in these children are warranted to identify their exposure sources and proper risk management strategies.

Effects of lead, mercury, aluminium and manganese co-exposure on the serum BDNF concentration of pre-school children in Taizhou, China

Previous studies have shown that toxic metal exposure can have adverse effects on the nervous system of children, but the toxicology of metal co-exposure on neurodevelopment remains to be clarified. Brain derived neurotrophic factor (BDNF) plays an important role in nervous system development, but the possible effects of metal co-exposure on the serum BDNF concentrations of children remain unknown. A total of 561 children living in Taizhou City, China were recruited to participate in our cross-sectional multicenter survey. We measured their blood Pb, Hg, Al and Mn levels and serum BDNF concentrations as well as determined their associations in the total and within sex subgroups. The geometric means of the blood Pb, Hg, Al and Mn levels in all the participants were 67.18 μg/L, 1.01 μg/L, 52.03 μg/L and 18.26 μg/L, respectively. The serum BDNF concentration in children was 19.45 ng/mL. After adjusting for confounders, the blood Pb levels were significantly negatively associated with the serum BDNF concentrations in all the subjects and boys but not in girls. In addition, a significantly negative interaction between blood Pb and blood Hg and a positive interaction between blood Pb and blood Al on serum BDNF concentrations were also observed in boys but not in girls. Our findings highlight the toxic effects of metal co-exposure on serum BDNF levels in pre-school children and indicate that these effects might differ by gender, which suggest that special attention should be paid to the sex-specific effects of metal exposure.

Analysis of the Relationship Between Hemorheologic Parameters, Aluminum, Manganese, and Selenium in Smokers

Smoking is a significant risk factor in fatal pathologies including cardio-cerebrovascular and respiratory diseases. Aluminum (Al) is a toxic element without known biological function, but with recognized toxic effects. Manganese (Mn) and selenium (Se) are essential trace elements involved in cellular antioxidant defense mechanisms. Al, Mn, and Se carry out their metabolic activities via blood flow and tissue oxygenation. The structure and number of red blood cells (RBC) play important role in tissue oxygenation throughout blood flow. Increased hematocrit (Hct) as a result of probable hypoxia induces disturbed blood flow, RBC aggregation (RBC Agg), RBC deformability index (Tk), and oxygen delivery index (ODI). Therefore, we aimed to investigate the effects of altered Al, Mn, and Se levels on number, structure, and function of RBCs (Hct, blood and plasma viscosity (BV and PV, respectively), RBC Agg, Tk, ODI) in smokers without diagnosis of chronic obstructive pulmonary disease (COPD) in a study group (n = 128) categorized as ex-smokers (ES), smokers (S), and healthy controls (HC). Elements were analyzed in serum using ICP-OES. BV and PV were measured via Brookfield and Harkness viscometers at 37 °C, respectively. Smokers had statistically higher serum Al and Mn levels, BV, RBC, Hgb, Hct, PV, fibrinogen, RBC Agg, Tk₄₅, and pulmonary blood flow rate, but lower serum Se levels and ODI₄₅ values versus HC. In conclusion, increased Al, Mn, and hemorheological parameters and decreased Se and ODI₄₅ might result from inflammatory response in defense mechanism in smokers without diagnosis of COPD. Our results point out that serum Al, Mn, and Se with hemorheological parameters may be beneficial markers of tissue oxygenation and defense mechanism before the clinic onset of COPD in smokers.

Serum Concentrations of 15 Elements Among Helicobacter Pylori-Infected Residents from Lujiang County with High Gastric Cancer Risk in Eastern China

Helicobacter pylori (H. pylori) infection can interfere with the absorption of most elements, and the variations of some element levels are related to the incidence of gastric cancer. However, there have been conflicting results concerning the influence of H. pylori infection on serum element levels. The present study aimed to compare the serum element concentrations of H. pylori-infected local residents with uninfected residents from Lujiang County with high gastric cancer risk in Eastern China. We used data and serum samples from the H. pylori screening-survey program which was a cross-sectional study. We took 155 samples randomly from the screening survey, identified 74 H. pylori-positive residents and 81 H. pylori-negative residents by a serological test. The serum concentrations of 15 elements (calcium, magnesium, iron, zinc, selenium, copper, molybdenum, chromium, cobalt, nickel, lead, cadmium, mercury, arsenic, and aluminum) were determined using inductively coupled plasma mass spectrometry. Serum cobalt was found at higher levels in the H. pylori-infected residents than the H. pylori-uninfected residents (0.246 vs 0.205 μg/L, P = 0.022), but no statistically significant differences in the serum levels of other elements were found. This is the first study to report the serum concentrations of 15 elements and their relationships with the infection status of H. pylori among local residents from Lujiang County with high gastric cancer risk. Although the International Agency for Research on Cancer has classified cobalt and other soluble cobalt salts as possibly carcinogenic to human beings, our results may provide a clue to the relationships between cobalt, H. pylori, and gastric cancer.

Polydopamine Dots-Based Fluorescent Nanoswitch Assay for Reversible Recognition of Glutamic Acid and Al3+ in Human Serum and Living Cell

We developed a facile and feasible fluorescent nanoswitch assay for reversible recognition of glutamate (Glu) and Al³⁺ in human serum and living cell. The proposed nanoswitch assay is based on our recently developed method for controlled synthesis of fluorescent polydopamine dots (PDADs) at room temperature with dopamine as the sole precursor. The fluorescence of nanoswitch assay could be quickly and efficiently quenched by Glu (turn-Off), and the addition of Al³⁺ could recover the fluorescence of the PDADs-Glu system (turn-On). Meanwhile, the reversible recognition of Glu and Al³⁺ in this nanoswitch system was stable after three cycles. Additionally, the system displayed excellent performance for Glu and Al³⁺ determination with a low detection limit of 0.12 and 0.2 μM, respectively. Moreover, PDADs are successfully applied to determine Glu and monitor Al³⁺ in human serum. Noteworthy, the nanoswitch assay is transported into HepG2 cells and realized "Off" detection of Glu and "On" sensing Al³⁺ in the living cells. Therefore, this PDADs-based nanoswitch assay provides a strategy to develop reversible recognition biosensors for intracellular and external molecular analysis.

Aluminium (Al) speciation in serum and urine after subcutaneous venom immunotherapy with Al as adjuvant

BACKGROUND

Aluminium is associated with disorders and is the commonly used vaccine adjuvant. Understanding the mechanisms of how Al is transported, metabolized or of its toxicity depends on the knowledge of Al-interactions with bioligands, i.e. Al-species. Al-speciation in serum is difficult because of low concentration and the risk of exogenous Al contamination. Furthermore, Al-measurements may be hampered according to various interferences. This study aims for developing quality controlled protocols for reliable Al- and Al-species determination and for investigating probable differences in Al (-speciation) after Al-containing subcutaneous immunotherapy (SIT).

METHODS

Sample donors were recruited either for the control group ("class-0", they never had been treated with SIT containing an Al-depot extract) or for the SIT-group ("class-1", they previously had been treated with SIT for insect venom allergy with an Al-depot extract). Blood was drawn for medical reasons and serum prepared. Additionally, some sample donors collected 24-h-urine. They had been informed (and they consented) about the scientific use of their samples. The study was approved by the ethic committee of the "Medical Association Westphalia-Lippe" and of the University of Münster, evaluating the study positively (No. 2013-667-f-S). We applied quality controlled sample preparation and interference-free Al detection by ICP sectorfield-mass spectrometry. Al-species were analysed using size-exclusion-chromatography-ICP-qMS.

FINDINGS

Al-concentrations or speciation in urine samples showed no differences between class-0 and class-1. Al-citrate was the main uric Al-species. In serum elevated Al-concentrations were found for both classes, with class-1 samples being significantly higher than class-0 (p = 0.041), but class-0 samples being approximately 10-fold too high compared to reference values from non-exposed persons. We identified gel-monovettes as contamination source. In contamination-free samples from HNO₃-prewashed gel-free monovettes (n = 27) there was no difference in the serum Al concentration between the two patient groups (p = 0.669) INTERPRETATION: Thorough cleaning of sample preparation ware and use of gel-free monovettes is decisive for an accurate Al analysis in serum. Without these steps, wrong analysis and wrong conclusions are likely. We conclude that gel-monovettes are unsuitable for blood sampling with subsequent Al-analysis. Whether Al in serum is elevated after SIT treatment containing an Al-depot extract, or not, remains inconclusive as the non-contaminated sample size was small.

Application of a Novel "Turn-on" Fluorescent Material to the Detection of Aluminum Ion in Blood Serum

A novel "turn-on" fluorescent bioprobe, 1,2,3,4,5-penta(4-carboxyphenyl)pyrrole sodium salt (PPPNa), with aggregation-enhanced emission characteristics was synthesized for the in situ quantitative detection of Al³⁺ in serum. It exhibited a high selectivity to Al³⁺ in both simulated serum and fetal calf serum with no interferences from other metal ions or serum components observed and no isolation required. A weak interaction between PPPNa and serum albumin was found, which caused no interference, but enhanced fluorescence response of PPPNa to Al³⁺ and improved detection sensitivity. The limit of detection was determined to be 1.50 μmol/L Al³⁺ in phosphate-buffered saline solution containing 33 μg/mL bovine serum albumin (BSA) and decreased to 0.98 μmol/L as BSA concentration increased to 100 μg/mL. The fluorescence "turn-on" mechanism of the PPPNa probe to detect Al³⁺ was proposed. A bidentate complex is formed between the carboxy group of PPPNa and Al³⁺, causing the photoluminescence (PL) emission enhancement by aggregation. BSA chains further strengthen the stacking compactness of the aggregates of PPPNa and Al³⁺ and consequently enhance the PL emission of PPPNa by further promoting the restriction of intramolecular rotation of the phenyl ring. Its application to the in situ Al³⁺ was successfully demonstrated with HeLa cells and NIH 3T3 cells. The low cytotoxicity and highly selective response of PPPNa to Al³⁺ endow its great potentials to in vivo detecting and imaging of Al³⁺ as well as an absorbent of Al³⁺.

Prenatal Exposure to Aluminum and Status of Selected Essential Trace Elements in Rural South African Women at Delivery

This study sought to evaluate the in utero exposure to aluminum and status of selected trace elements in South African women at delivery since aluminum is known to be toxic in all developmental stages even at low concentrations. Serum aluminum was negatively correlated with aluminum in urine, both uncorrected and corrected for creatinine, which suggests the retention of aluminum in body stores. Serum copper and zinc levels were found to be high in this study population. Serum copper levels were negatively correlated with aluminum in serum (β = -0.095; p = 0.05). There was a marginal negative correlation between aluminum levels in serum and manganese levels in whole blood (β = -0.087; p = 0.08). Copper levels in maternal serum were negatively correlated with birth weight and the length of neonates. There were a number of positive correlations between maternal characteristics and birth outcomes. Mothers who consumed root vegetables frequently appeared to be protected from aluminum retention and increased body burden since their serum aluminum levels were found to be significantly lower. The findings of the current study can be used as a baseline for further research on aluminum exposure and its associated interactions and outcomes in vulnerable populations.

Elevated heavy metals levels in cognitively impaired patients from Pakistan

The deficit in the visuospatial skills, thinking, learning and memory is termed as cognitive impairment. Human exposure to heavy metals is a potential risk factor for developing cognitive impairment. This study aimed to investigate the possible association between the concentration of heavy metals and the extent of cognitive impairment. Blood samples were subjected to microwave assisted acid digestion and evaluated for metals levels using atomic absorption spectrophotometry. We measured the levels of Cu, Pb, Al, Zn, Cd and Mn in 183 patients diagnosed with cognitive impairment; mild (n = 72), moderate (n = 86) and severe (n = 25) and compared them to age-matched healthy controls (n = 90). Results showed that all the aforementioned elements were significantly higher in cognitively impaired patients and increasing concentration was strongly correlated with increase in severity of the disease. The correlation study has shown that among the studied metals, Al and Cu are strongly associated with the cognitive impairment. This suggests the need for decrease in metal exposure to humans from environment, food and industries.

A highly selective and sensitive turn-on probe for aluminum(III) based on quinoline Schiff's base and its cell imaging

A reversible Schiff's base fluorescence probe for Al³⁺, (3,5-dichloro-2- hydroxybenzylidene) quinoline-2-carbohydrazide (QC), based on quinoline derivative has been designed, synthesized and evaluated. The QC exhibited a high sensitivity and selectivity toward Al³⁺ in EtOH-H₂O (v/v=1:9, pH=6) by forming a 1:1 complex with Al³⁺ and the detection limit of QC for Al³⁺ was as low as 0.012μM. Furthermore, these results displayed that the binding of QCAl³⁺ was broken by F^-, so this system could be used to monitor F^- in the future. The enhancement fluorescence of the QC could be attributed to the inhibition of PET and ESIPT and the emergency of CHEF process induced by Al³⁺. More importantly, QC was not only successfully used for the determination of trace Al³⁺ in the tap water and the human blood serum, but was valid for fluorescence imaging of Al³⁺ in the Hela cells.

Neuroprotective effect of Moringa oleifera leaf extract on aluminium-induced temporal cortical degeneration

Aluminium (Al), one of the metals implicated in neurodegeneration easily gain access to the nervous system through its presence in many manufactured foods, medicines and drinking water, and causes neurotoxicity utilizing the reactive oxygen specie pathway. The need to curtail these effects on the nervous system motivated the use of the plant Moringa oleifera (MO). This study thus, investigated the neuroprotective effects of MO leaf extract on aluminium-induced temporal cortical degeneration in rats. 24 male albino Wistar rats were grouped (n = 6) into control (1 ml/kg distilled water), l00 mg/kg aluminium chloride (AlCl₃), 300 mg/kg MO, and 100 mg/kg AlCl₃ and 300 mg/kg MO groups. The administration lasted for 28 days and the rats were sacrificed on day 29 by perfusion-fixation after blood was obtained for serum Al estimation. The brain tissues were then routinely processed for some histological and immunnolabelling studies. There was no significant difference in serum Al in the test groups. Histological results showed atrophied and karyorrhetic cells with loss of Nissl substance in the temporal cortex of the AlCl₃ group, while no adverse effect was observed in the cytoarchitecture of the temporal cortex and Nissl substance of the MO group. However, groups which were administered AlCl₃ simultaneously with MO extract showed less degenerative features in the cyto-architecture of the temporal cortex with normal Nissl substance staining. There was increased neuron specific enolase (NSE) and glial fibrillary acidic protein (GFAP) expressions in the AlCl₃ group, while the MO group also showed increased NSE but decreased GFAP expression. However, the group which were administered AlCl₃ simultaneously with MO extract showed less expression of NSE and GFAP. In conclusion, MO protects against Al-induced neurotoxicity of the temporal cortex of rats.

Increased Serum Al Levels in Hemodialysis Patients Kept Enhanced during a 2-Year Prospective Study

The regulation of mineral homeostasis is altered in hemodialysis patients with renal insufficiency, producing increased risk for secondary diseases like cardiovascular ones. We hypothesized that risen serum aluminum (Al) concentration in hemodialysis patients kept enhanced during a 2-year longitudinal study is associated with enhanced cardiovascular risk and influenced by medical treatments. This study reports the prospective monitoring of serum Al levels in six-monthly samplings over 2 years in 116 hemodialysis patients and a control group of 50 healthy adults. The influence of other factors like sex, age, kidney transplant, disease etiology, and drug consumption was also considered. At each sampling, serum Al levels were significantly higher in the patients than in the healthy controls (P < 0.05). Levels in the patient group were statistically significantly lower at the third and fourth versus first and second samplings, which may be related to Al accumulation in tissues. Increased Al levels in patients were positively and significantly related to serum calcium (Ca) and uric acid levels. Serum Al concentrations were significantly lower in patients receiving vasodilators and diuretics. Higher serum Al levels in hemodialyzed patients administered with phosphate binders or anti-hyperkalemics are attributable to their usual Al salt content. The consumption of antianemic drugs increases Al absorption by forming more bioavailable complexes with the compounds in these drugs. In conclusion, this is the first study to indicate that cardiovascular problems associated with elevated serum Al levels in hemodialysis patients may be in part mitigated by administrating vasodilators and diuretics, which reduce these levels.

In end-stage renal failure, does infection lead to elevated plasma aluminium and neurotoxicity? Implications for monitoring

The well-described long-term effects of sustained exposure to aluminium in patients with end-stage renal failure (ESRF) are a result of uptake and storage of aluminium, leading to cellular toxicity. A case is presented suggesting that this aluminium may be mobilizable, and indicating the consequence of such release.

A patient on haemodialysis (HD) presented acutely with infection, a raised CRP, decreased conscious level, impaired cognition and agitation. Subsequent neurological recovery over six to seven days appeared to follow the return of markedly elevated plasma aluminium concentrations to basal (i.e. from 25.2 μmol/L to 2.5 μmol/L; reference range <0.5 μmol/L), coupled with a resolution of the infection. The patient was on long-term aludrox therapy 3 g/day, and showed relative resistance to the exogenous hormone erythropoietin, resulting in a refractory anaemia and suggesting aluminium toxicity. A series of HD patients ( n=5) presenting with bacteraemia, not on aludrox, showed no appreciable rise in the plasma aluminium mean of 1.3 μmol/L (SD 0.9; range 0.6-2.0 μmol/L). We suggest that infection can result in release of tissue aluminium, leading to acutely elevated plasma aluminium concentrations and signs of neurotoxicity. The amount of tissue storage and resultant aluminium release seemed to be related to the use of aluminium hydroxide as a phosphate binder.

Plasma aluminium: a redundant test for patients on dialysis?

Background: Aluminium toxicity as a cause of dementia, osteodystrophy and anaemia in patients receiving renal dialysis was first described in the 1970s and led to the regular monitoring of aluminium in plasma and dialysate water. However, aluminium phosphate binders have now been replaced by calcium-based binders or sevelamer and reverse osmosis (RO) water is used in the preparation of dialysate fluid. This has reduced the exposure of dialysis patients to aluminium and it is therefore opportune to review aluminium monitoring in patients undergoing regular renal dialysis.

Methods: Plasma and water aluminium results were audited over the period January 2000-January 2004, with results obtained from nine renal dialysis units in the UK. Patients with a plasma aluminium concentration in the toxic range (>3.7 μmol/L) were followed up by contacting the relevant consultant.

Results: Plasma aluminium results were collected on 1626 patients over the fouryear period (mean = 0.47 μmol/L, median = 0.3 μmol/L, range 0.07-30.26 μmol/L, n = 5918). Forty-six patients had an aluminium concentration >3.7 μmol/L and nine were not retested. Only three patients had a repeat aluminium concentration >2.2 μmol/L, one being a result of desferrioxamine treatment, with no further clinical information available on the other two. All renal units are using RO water to prepare dialysate and aluminium-based phosphate binders are no longer prescribed. Only one of 212 RO water aluminium concentrations measured was >10 μg/L. Patients with clinical symptoms of overt aluminium toxicity were not identified in this population.

Conclusion: The role of aluminium monitoring in long-term renal dialysis patients needs re-evaluation. Regular monitoring of plasma aluminium may not be required, but should be considered in any patient showing signs or symptoms of aluminium toxicity or exposed to a contaminated water supply. It is more important that RO water supplies are maintained and monitored. Environmental aluminium as a source of sample contamination should be considered and eliminated during blood collection and sample processing.

Shift from darbepoetin-α to continuous erythropoietin receptor activator decreases serum aluminium concentration in patients on hemodialysis

OBJECTIVE

The response of erythropoietic stimulating agents (ESA) in uremic patients may be associated with the changes of biochemical parameters, metal elements and inflammation status during the shift from one ESA to another.

METHOD

We compared changes in above mentioned factors after switching from darbepoetin-α (DPO) 20μg weekly for 10 weeks to continuous erythropoietin receptor activator (CERA) 100μg monthly for 10 weeks in uremic patients on hemodialysis. The haematocrit (Hct), metal elements and inflammation status are the primary outcome. Subjects included 54 patients without transfusion or bleeding or additional ESAs. Responders (IR, n=36) were defined as patients with an increase in Hct after the swtich.

RESULT

Although there was no significant difference in overall mean Hct after the switch (p=0.135), there are significantly greater mean number of red blood cells (RBC) (p=0.006), higher platelet numbers (p=0.001), larger RBCs (p=0.017) and higher creatinine (p=0.04) and total cholesterol (T-CHOL) (p=0.003) levels. Mean overall aluminium (Al) level decreased significantly (p=0.001). C-reactive protein (CRP) also decreased (p=0.016). The overall LDH increased (p=0.049) and potassium decreased significantly (p=0.036), which indicating active erythropoiesis. The calcium (Ca) level was significantly higher (p=0.034) and phosphate was significantly lower (p=0.028) after the shift. Although there was no significant increase in overall levels of parathyroid hormone (PTH) after the shift (p=0.061), but the pre-shift and post-shift PTH level was significantly higher in IRs than in non-IRs (p=0.003 and p=0.027, respectively). IRs had a significantly lower initial T-CHOL (p=0.03) and initial CRP (p=0.012) than non-responders, which may be related to lower inflammation.

CONCLUSION

We found the shift from DPO to CERA results in lower Al levels, a reduced inflammatory response, and an increase in RBC number and PTH level in uremic patients on hemodialysis.

Measurement of Serum Sodium and Magnesium by Inductively Coupled Plasma Mass Spectrometry with Aluminum as Internal Standard

BACKGROUND

Serum sodium and magnesium are important clinical laboratory tests and accurate testing results are needed for the correct interpretation of the tests. Standardization of serum sodium and magnesium measurements requires simple and reliable reference methods.

METHODS

Inductively coupled plasma mass spectrometry (ICP-MS) methods for the measurement of serum sodium and magnesium were developed. Aluminum was used as an internal standard. Serum samples were spiked with the internal standard, digested with 69% nitric acid at 150 degrees C and measured for 23Na/27Al and 24Mg/27Al ratios by ICP-MS. The measurements were calibrated by bracketing calibrators and serum sodium and magnesium concentrations were calculated by comparing the ion ratios of the serum samples with that of the calibrators.

RESULTS

The correlation coefficients between the measured ion ratios and the analyte concentrations were all > 0.9999 for both sodium and magnesium. The coefficients of variation of the measurements were 0.07% - 0.14% for sodium and 0.21% - 0.36% for magnesium. No significant interferences were detected and the analytical recoveries were 100.25% and 100.11% for sodium and magnesium, respectively. The accuracy of the measurements was also verified through measurement of certified reference materials and participation in international interlaboratory comparisons.

CONCLUSIONS

New ICP-MS methods for serum sodium and magnesium have been developed. The methods are specific, precise, simple and low in cost and may be used as candidate reference methods in the standardization of serum sodium and magnesium measurements.

Correlation of cadmium and aluminum in blood samples of kidney disorder patients with drinking water and tobacco smoking: related health risk

The combined exposure to aluminum (Al) and cadmium (Cd) causes more pronounced adverse health effects on humans. The kidneys are the main organs affected by internal exposure to Cd and Al via food and non-food items. The objective of present study was to measure the Al and Cd concentrations in cigarettes tobacco (branded and non-branded) and drinking water (domestic treated, ground and lake water) samples in southern part of Pakistan, to assess the risk due to ingestion of water and inhalation of cigarettes smoke containing high concentrations of both elements. The study population (kidney disorder and healthy) divided into two group based on consuming lake and ground water, while smoking non-branded cigarette as exposed, while drinking domestic treated water and smoking branded cigarette as non-exposed. Electrothermal atomic absorption spectrometry was used to determined Cd and Al concentrations in tobacco, drinking water and blood samples. The resulted data indicated that the levels of Al and Cd in lake and underground water were higher than the permissible limit in drinking water recommended by the World Health Organization. The biochemical parameters of exposed and referent patients, especially urinary N-acetyl-h-glucosaminidase, were used as a biomarkers of kidney disorder. Exposed kidney disorder patients have higher levels of Cd and Al than the exposed referents subjects, while difference was significant when compared to resulted data of non-exposed patients and referents (p = 0.01-0.001). The pearson correlation showed positive correlation between both toxic element concentrations in water, cigarettes versus blood samples of exposed subjects (r = 0.20-0.67 and 0.71-0.82), while lower values were observed for non-exposed subjects (r = 0.123-0.423 and 0.331-0.425), respectively.

Therapy and monitoring of hypersiderosis in chronic renal insufficiency

In RDT hemosiderosis appears to be an inevitable complication only in the small number of patients in need of frequent transfusions. To prevent clinical consequences (e.g. cardiomyopathy) known from polytransfused patients without renal disease, transplantation should be considered in RDT patients in need of frequent transfusions. Iron substitution - preferably oral - to replace dialysis-related iron loss does not cause clinically significant hemosiderosis provided iron stores are monitored adequately. A sufficient method of controlling iron stores in RDT patients under iron substitution or regular transfusion therapy is a twice annual determination of serum ferritin concentration. The treatment of choice for hemosiderosis in nontransfused RDT patients is discontinuation of iron substitution. When polytransfused RDT patients with severe hemosiderosis cannot be transplanted and submitted consecutively to phlebotomy, DFO treatment is indicated. Quantitative data regarding optimal dosage and application of DFO in RDT patients are not yet available. Constant infusion of DFO during hemodialysis may be superior to bolus application.

The binding, transport and fate of aluminium in biological cells

Aluminium is the most abundant metal in the Earth's crust and yet, paradoxically, it has no known biological function. Aluminium is biochemically reactive, it is simply that it is not required for any essential process in extant biota. There is evidence neither of element-specific nor evolutionarily conserved aluminium biochemistry. This means that there are no ligands or chaperones which are specific to its transport, there are no transporters or channels to selectively facilitate its passage across membranes, there are no intracellular storage proteins to aid its cellular homeostasis and there are no pathways which evolved to enable the metabolism and excretion of aluminium. Of course, aluminium is found in every compartment of every cell of every organism, from virus through to Man. Herein we have investigated each of the 'silent' pathways and metabolic events which together constitute a form of aluminium homeostasis in biota, identifying and evaluating as far as is possible what is known and, equally importantly, what is unknown about its uptake, transport, storage and excretion.

Comparative evaluation of essential and toxic elements in the blood of kidney failure patients and healthy referents

The aim of the present study was to evaluate the comparative distribution, correlation, and apportionment of selected elements-aluminum (Al), calcium (Ca), cadmium (Cd), potassium (K), magnesium (Mg), sodium (Na), and lead (Pb)-in the blood samples of male kidney failure patients (KFP) and healthy subjects of age ranged 30-60 years. The blood samples were digested with nitric acid and perchloric acid mixture (2:1), followed by the quantification of elements by atomic absorption spectrometry. The concentration of essential elements in blood samples of KFP were found in the range of Ca (97-125), Mg (18-36), Na (2971-3685), and K (177-270) mg/L while, the levels of Al, Cd, and Pb were found in the range of (475-1275), (0.9-9.9), and (211-623) μg/L, respectively. In the healthy referents, concentration of electrolytes in blood samples was lower than KFP, but difference was not significant (p > 0.05). While the levels of toxic elements in blood samples of referents were three- to sixfold lower than KFP (p < 0.01). Principal component analysis (PCA) and cluster analysis (CA) of the element data manifested diverse apportionment of the selected elements in the blood sample of the KFP compared with the healthy counterparts.

Plasma and mitochondrial membrane perturbation induced by aluminum in human peripheral blood lymphocytes

Aluminum is a redox-inert element that could induce cell damage via activation of oxidative stress. In this work, the effect of aluminum on different cellular compartments of human peripheral blood lymphocytes was studied. The presence of aluminum induced a lipid peroxidation and physico-chemical modifications at the membrane level. A decrease in fluorescence anisotropy of TMA-DPH and in the polarity of the lipid bilayer with a concomitant shift toward a gel phase was observed, while the pyrene excimerization coefficient (Kex) increased. Flow cytometry measurements, using JC-1, Rhodamine 123 and H2-DCFDA as fluorescent probes, indicated that aluminum induces a slight mitochondrial membrane depolarization that was associated with a moderate increase in reactive oxygen species production. A significative influence on these parameters was measured only at high aluminum concentration.

Chronic exposure to aluminum, nickel, thallium and uranium and their relationship with essential elements in human whole blood and blood serum

This study aimed to evaluate the influence of exposure to aluminum, nickel, thallium and uranium on the metabolism of essential elements in humans, as well as the relationship between uranium, thallium, nickel, and aluminum and essential elements (Ca, Mg, Zn, Se, Mn, Co, Cr, and Mo) in the whole blood and blood serum of healthy men who were occupationally exposed. This study included 97 healthy men, 31-64 years age, including 70 workers in a thermo power plant and 27 control subjects. The results showed that chronic, moderate exposure of trace elements (Al, Ni, Tl, and U) lead to decreased serum chromium (SCr) and blood molybdenum levels (BMo), whereas by the results achieved in terms of correlations between non-essential and essential elements, non-essential elements such as uranium, thallium, nickel, and aluminum, despite their concentration within the reference values, are strongly competitive with essential elements in biochemical processes.

Chemometric methods for studying the relationships between trace elements in laryngeal cancer and healthy tissues

A quick and reliable method for the evaluation and classification of two types of tissues is presented. Several chemometric methods were applied to evaluate multivariate data of the tissue samples with respect to the content of trace elements. The content of Pb, Al, Zn, Cd, Cu, Ni and Co was determined in samples of healthy and cancerous tissue obtained from 26 patients. Determination was done at milligram/kilogram level with inductively coupled plasma optical emission spectrometry (ICP-OES) and atomic absorption spectroscopy (AAS) techniques. Contents of trace metals in studied tissues are not normally distributed; however, normal distribution was confirmed for log values. There is a statistically significant difference in the content of Zn, Cd, Cu and Al (p<0.01) and Ni and Co (p<0.05) when healthy tissue is compared to cancerous one. Correlation between contents of trace elements for studied tissues was positive; the highest was found between Zn and Cu. A chemometric methodology seems to be a promising tool for classifications of the tissue samples.

[Experimental evaluation of combined effects caused by stress and metals (cadmium and aluminium) in reproductivity of male rats]

To investigate combined effects of stress and metal (aluminium, cadmium) on reproductivity, male rats twice per week received intraperitoneal injections of aluminium (3.8 mg Al3+ per kg of body weight) or cadmium (0.3 mg Cd2+ per kg of body weight) and were subjected to stress via short-term immobilization during spermatogenic cycle (54 +/- 3 days). Findings are cumulation of both cadmium and aluminium in genitals and brain, increasing under stress. When acting separately to the laboratory animals, the three factors (aluminium/cadmium/stress) increase serum corticosterone level, change testosterone level, increase number of aberrant mitoses of spermatogenic epithelium cells, increased sperm count with fragmented DNA, lower percentage of the impregnated females. If the exposure combined with stress, spermatogenesis disorders are more marked, and preimplantation death rate of intact females' offspirngs becomes statistically significant.

Computer simulation of speciation of trivalent aluminum, gadolinium and yttrium ions in human blood plasma

The speciation of Al3+, Gd3+ and Y3+ ions in human plasma has been studied by computer simulation using the program HySS2009. A literature computer model of blood plasma was updated and comprised 9 metals, 43 ligands and over 6100 complexes. To this model critically evaluated data of Al3+, Gd3+ and Y3+ constants with blood plasma ligands have been added. Low molecular mass (LMM) speciation of Al3+ ion strongly depends upon the chosen equilibrium model of the metal - phosphate and metal - citrate systems. The obtained computer simulation of LMM speciation data of Al3+ ion were: AlPO4Cit (40.7%), AlPO4CitOH (22.9%), AlCitOH (19.2%) and AlPO4(OH) (12.7%) (% of total LMM Al species pool); for Gd3+ ion: GdAspCit (30%) and GdCit(OH)2 (20%) (% of total [Gd]) and for Y3+ ion: YCit (48%), Y(CO3)2 (32%) and Y(CO3) (11%) (% of total [Y]). Citrate appears as the important binding and mobilizing ligand for all examined ions, while the dominating species are the ternary ones.