Scalp hair as an indicator of aluminium exposure: comparison to bone and plasma

Characterization of bone aluminum, a potential biomarker of cumulative exposure, within an occupational population from Zunyi, China

OBJECTIVES

Aluminum (Al) is a neurotoxicant; however, efforts to understand Al toxicity are limited by the lack of a quantitative biomarker of cumulative exposure. Bone Al measurements may address this need. Here, we describe and compare non-invasive bone Al measurements with fingernail Al and Al cumulative exposure indices (CEIs).

METHODS

We completed a cross-sectional study of 43 factory workers in Zunyi, China. Bone Al measurements were taken with a compact in-vivo neutron activation analysis system (IVNAA). Fingernail samples were analyzed using inductively coupled plasma mass spectrometry. CEIs, based on self-reported work history and prior literature, were calculated for the prior 5, 10, 15, 20 years and lifetime work history. Linear regressions adjusted for age and education compared fingernail Al and Al CEIs with bone Al.

RESULTS

Median (interquartile range (IQR)) Al measurements were: 15 μg/g dry bone (IQR = 28) for bone Al; 34.9 μg/g (43.3) for fingernail; and 24 (20) for lifetime CEI. In adjusted regression models, an increase in 15-year CEI was significantly associated with increased bone Al (β = 0.91, 95% confidence interval (CI): 0.16, 1.66). Associations of bone Al with 10- and 20-year CEI were approaching statistical significance (β = 0.98, 95% CI: -0.14, 2.1; β = 0.59, 95% CI: -0.01, 1.18, respectively). Other models were not statistically significant.

CONCLUSIONS

Bone Al was significantly associated with 15-year Al CEI, but not other Al CEIs or fingernail Al. Bone Al may be a useful measure of cumulative, rather than short-term, Al exposure. Additional refinement of this method is ongoing.

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.

Assessment of hair metal levels in aluminium plant workers using scalp hair ICP-DRC-MS analysis

The objective of the present study was to assess the level of aluminium and toxic metals in hair of workers occupationally exposed to aluminium. 124 employees of the aluminium plant working in the hydrometallurgical (n = 43) and sintering units (n = 41), as well as 40 occupationally nonexposed controls were examined. Hair aluminium (Al), arsenic (As), beryllium (Be), cadmium (Cd), mercury (Hg), nickel (Ni), lead (Pb), and tin (Sn) content was assessed using inductively-coupled plasma mass spectrometry. The obtained data demonstrate that aluminium plant workers had significantly higher levels of hair Al (28.8 (15.4-58.6) vs 7.8 (4.3-14.2) μg/g, p < 0.001), Cd (0.053 (0.032 - 0.095) vs 0.025 (0.014 - 0.043) μg/g, p < 0.001) and Pb (0.672 (0.299-1.310) vs 0.322 (0.170 - 0.609) μg/g, p = 0.012) than the controls, respectively. Further analysis demonstrated that persons involved in different technological processes were characterized by distinct hair metal profiles. Hair Al, Be, Cd, Ni, Pb, and Sn levels in men working in the sintering unit of the aluminium plant exceeded the respective control values. In turn, workers of the hydrometallurgical unit were characterized by more than 2-fold higher levels of Al and Cd in hair as compared to the controls. The results of the present study demonstrate that workers of the aluminium plant are characterized by increased risk of Al as well as As, Cd, Pb, and Sn exposure.

Mitigation of Acute Aluminum Toxicity by Sodium Selenite and N-Acetylcysteine in Adult Male Rats

The objective of this study is to investigate the toxic effects of aluminum and the potential alleviation of selenite and N-acetylcysteine (NAC) on this toxicity. Acute aluminum toxicity was induced by intraperitoneal (i.p.) injection of AlCl₃ (30 mg Al³⁺/kg) for four consecutive days. Al³⁺ damaged the synthetic capability and regeneration power of liver cells and induced inflammation. It also damaged the kidney and disturbed the lipid profile enhancing the total cholesterol level and LDL-cholesterol level increasing the risks of atherosclerosis. Al³⁺ reduced the cellular antioxidant milieu typified by the decrease in reduced glutathione, vitamin E, and four antioxidant enzymes and induced lipid peroxidation (LPO). Selenite at 1 mg Se/kg and NAC at 150 mg/kg injected either simultaneously with or after Al³⁺ mitigated most of these damaging effects probably by the virtue of scavenging the free radicals, binding aluminum and stimulating its excretion and reducing its bioavailability, bolstering the endogenous antioxidant defense systems, stabilizing the cell membrane, and preventing LPO. The beneficial effects of selenite and NAC against aluminum toxicity were also confirmed by the light and electron histopathology study. There were no significant differences between the two regimens used (protection and therapeutic) in the current study probably due to the short time of exposure, and the abrogation of Al³⁺ toxicity offered by selenite was better than that provided by NAC on the histopathology level.

Role of Metabolic Genes in Blood Aluminum Concentrations of Jamaican Children with and without Autism Spectrum Disorder

Aluminum is a neurotoxic metal with known health effects in animals and humans. Glutathione-S-transferase (GST) genes and enzymes play a major role in detoxification of several heavy metals. Besides a direct relationship with oxidative stress; aluminum decreases GST enzyme activities. Using data from 116 Jamaican children; age 2–8 years; with Autism Spectrum Disorder (ASD) and 116 sex- and age-matched typically developing (TD) children; we investigated the association of polymorphisms in three GST genes (GSTP1; GSTM1; and GSTT1) with mean blood aluminum concentrations in children with and without ASD. Using log-transformed blood aluminum concentration as the dependent variable in a linear regression model; we assessed the additive and interactive effects of ASD status and polymorphisms in the three aforementioned GST genes in relation to blood aluminum concentrations. Although none of the additive effects were statistically significant (all p > 0.16); we observed a marginally significant interaction between GSTP1 Ile105Val (rs1695) and ASD status (p = 0.07); even after controlling for parental education level and consumption of avocado; root vegetables; and tuna (canned fish). Our findings indicate a significantly lower (p < 0.03) adjusted geometric mean blood aluminum concentration for TD children who had the Val/Val genotype (14.57 µg/L); compared with those with Ile/Ile or Ile/Val genotypes who had an adjusted geometric mean of 23.75 µg/L. However; this difference was not statistically significant among the ASD cases (p = 0.76). Our findings indicate that ASD status may be a potential effect modifier when assessing the association between GSTP1 rs1695 and blood aluminum concentrations among Jamaican children. These findings require replication in other populations.

Drinking deep-sea water restores mineral imbalance in atopic eczema/dermatitis syndrome

OBJECTIVE

The effect of drinking deep-sea water on hair minerals was studied in patients with atopic eczema/dermatitis syndrome (AEDS). Study of hair minerals revealed an imbalance of essential minerals and an increase in toxic minerals in AEDS patients.

DESIGN

After drinking deep-sea water (Amami no Mizu) for 6 months in AEDS patients, hair minerals (essential minerals and toxic minerals), clinical evaluation of the skin symptoms were compared before drinking with after drinking.

SUBJECTS

After obtaining informed consent, 33 patients (mean age 26 y, range 1-50 y, 13 male and 20 female subjects) with mild to moderate AEDS were enrolled.

RESULTS

After drinking deep-sea water, the levels of the essential mineral, potassium (K), were significantly decreased, while the levels of selenium (Se) increased. On the other hand, drinking deep-sea water significantly decreased the levels of the toxic minerals, mercury and lead. Moreover, after drinking deep-sea water, the skin symptoms were improved in 27 out of 33 patients.

CONCLUSION

These results indicate that the mineral abnormalities/imbalance may be involved in the pathogenesis of AEDS, and that drinking deep-sea water may be useful in the treatment of AEDS.

Longitudinal and lateral variations in the aluminum concentration of selected caprine, bovine, and human bone samples

Longitudinal and lateral variations in Al concentration in several large animal (bovine and caprine) long bones (tibia and femur) and several human clavicle bones were examined using a sensitive analytical method based on electrothermal atomization atomic absorption spectrometry with Zeeman background correction. Bone segments were carefully removed using special tools free of significant Al contamination, freeze-dried, and digested overnight at room temperature in concentrated HNO3. Bone digestates were analyzed for Al using simple aqueous calibration standards with a Ca(NO3)2 modifier. Mean bone Al concentrations were relatively low (<1 microg/g, dry weight) in bovine and caprine long bones compared to literature values for human bone samples. Longitudinal variations of Al in the animal bones examined appeared relatively uniform compared to the human clavicle bones, where, in three of five cases, Al appeared enriched at the epiphyses (joints). The Al "enrichment" was symmetrical with respect to both left and right clavicle bones. Aluminum concentrations at the mid-shaft of the clavicle bone show less variation compared to whole bone studies, but considerable scatter is evident along the bone length. The mean bone aluminum concentration in the five human subjects varied from 1 to 6 microg/g dry weight.

Adverse reactions after injection of adsorbed diphtheria-pertussis-tetanus (DPT) vaccine are not due only to pertussis organisms or pertussis components in the vaccine

Reactions to adsorbed diphtheria-pertussis-tetanus (DPT) vaccine have mostly been attributed to the pertussis organisms or pertussis components in the vaccine. Nevertheless reactions may also be due to other factors such as sensitization induced by aluminium adjuvants and impurities present in crude toxoids that cannot be removed by purification of toxoids after formalinization. Aluminium compounds such as aluminium phosphate and aluminium hydroxide are the most commonly used adjuvants with vaccines for human use. Due to the increasing concern about the toxicity of aluminium, other adjuvants like calcium phosphate may be evaluated as an alternative to aluminium adjuvants. To minimize reactions after immunization with DPT vaccine due to impurities in the toxoids, the use of toxoided purified toxins is suggested.