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Abstract Background The correlation between metals and hypertension, such as sodium, zinc, potassium, and magnesium, has been confirmed, while the relationship between aluminum and hypertension is not very clear. This study aimed to evaluate the correlation between plasma aluminum and hypertension in electrolytic aluminum workers by the Bayesian networks (BN). Methods In 2019, 476 male workers in an aluminum factory were investigated. The plasma aluminum concentration of workers was measured by inductively coupled plasma mass spectrometry. The influencing factors on the prevalence of hypertension were analyzed by the BN. Results The prevalence of hypertension was 23.9% in 476 male workers. The risk of hypertension from plasma aluminum in the Q2, Q3, and Q4 groups was 5.20 (1.90–14.25), 6.92 (2.51–19.08), and 7.33 (2.69–20.01), respectively, compared with that in the Q1 group. The risk of hypertension from the duration of exposure to aluminum of >10 years was 2.23 (1.09–4.57), compared without aluminum exposure. Area under the curve was 0.80 of plasma aluminum and the duration of exposure to aluminum was based on covariates, indicating that aluminum exposure had important predictive value in the prevalence of hypertension in the occupational population. The results of the study using the BN model showed that if the plasma aluminum of all participants was higher than Q4 (≥47.86 µg/L) and the participants were drinking, smoking, diabetes, central obesity, dyslipidemia, and aged >50 years, the proportion of hypertension was 71.2%. Conclusions The prevalence of hypertension increased significantly with the increase of plasma aluminum level.

Introduction: Progressive neural cell loss is a pathological hallmark of Alzheimer's disease (AD). Environmental factors should be taken into consideration due to their epigenetic link to AD, and also because most of the causal environmental factors are preventable. Aluminum (Al) as a common risk environmental factor has been reported to be related to AD. Nonetheless, the nature, time duration, and molecular mechanism of neural cell death in Al-induced AD remain poorly understood. The present article reviews the role of necroptosis, as a novel cell death pathway, in Al-induced AD models in vitro and in vivo. Methods: In the present review, Al-induced necroptosis is summarized in terms of neural cell death and AD animal models induced by Al compounds. Furthermore, a major role of necroptosis in AD is highlighted by comparing studies of apoptosis and autophagy in Al-induced neural cell death and AD animal models. Results: Current research on Al-induced necroptosis has been summarized in Al-treated neural cells and animal AD models. Treatment with Necrostatin-1 (Nec-1) as its specific inhibitor could down-regulate expression of cell death and necroptosis-related proteins; finally, AD-related expression of the signal pathway declined accordingly. The results consistently implied that Al could induce necroptosis, and that Nec-1 could suppress neural cell death pathways not only in Al-induced necroptosis but also in apoptosis and autophagy. Compared with the inhibitors of apoptosis and autophagy, the effects of Nec-1 were more prominent. It indicated that necroptosis is a dominant cell death pathway in Al-treated neural cells and animal models. Conclusion: Based on the relative literature, it has been suggested that necroptosis is involved in the process of Al-induced AD. It implies that Nec-1 represents a promising anti-Alzheimer's approach and has potential theoretical value in environmental factor Al-induced AD neuropathologies.

BackgroundAluminum activates signal transducer and activator of transcription 3 (STAT3), causing microglial nucleotide-binding and oligomerization domain-like receptors protein 3 (NLRP3) inflammasome activation and inflammatory responses and producing neurotoxicity.ObjectiveTo explore the role of STAT3 regulated NLRP3 inflammasomes in the inflammatory response of mouse microglia cell line (BV2) cells induced by maltol aluminum [Al(mal)3].MethodsBV2 cells were assigned to five groups: one control group, three Al(mal)3 exposure groups (low, medium, and high doses at 40, 80, and 160 μmol·L−1 Al(mal)3 respectively), and one C188-9 (STAT3 antagonist) intervention group [10 μmol·L−1 C188-9 +160 μmol·L−1 Al(mal)3]. Cell viability was detected by CCK8. The expression of M1/M2 type markers, i.e. CD68/CD206, STAT3, p-STAT3, NLRP3, cleaved-casepase-1, and apoptosis-associated speck-like protein (ASC) in BV2 cells were detected by Western blotting, and proinflammatory cytokines interleukin (IL)-1β and IL-18, and anti-inflammatory cytokine IL-10 were determined by ELISA.ResultsThe results of cell viability assay showed that cell viability gradually decreased with the increase of Al(mal)3 dose. Compared with the control group, the cell viability of the Al(mal)3 high-dose group was decreased by 18% (P0.05). Compared with the control group, the expression level of NLRP3 protein increased by 75% in the Al(mal)3 high-dose group (P0.05).ConclusionAluminum can induce inflammatory responses in BV2 microglia and is predominantly pro-inflammatory, and the mechanism may involve STAT3 regulation of NLRP3 inflammasome secretion of inflammatory factors.

BackgroundAluminum and fluoride are neurotoxic, and aluminum exposure alone is closely related to the overall cognitive function of operational workers. It is unclear about the effect of aluminum and fluoride interactions on cognitive function.ObjectiveTo evaluate a potential interaction effect of blood aluminum and urinary fluoride on the overall cognitive function of workers working in an aluminum plant.MethodsUsing cluster sampling, 230 workers in the electrolysis workshop of an aluminum group company in Shanxi Province were selected, and plasma aluminum concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS) and urinary fluoride by ion-selective electrode. The study participants were divided into a low blood aluminum group and a high blood aluminum group according to the median (M) of blood aluminum concentration, and a low urinary fluoride group and a high urinary fluoride group by a predetermined cutoff point (2.160 mg·L−1). The Montreal Cognitive Assessment-Beijing (MoCA-BJ) was used to assess overall cognitive function of the workers. Logistic regression model was used to analyze the relationship between blood aluminum, urinary fluoride, and mild cognitive impairment (MCI), including multiplicative interaction analysis and correlation analysis; R language was used to fit an additive interaction model of blood aluminum and urinary fluoride on MCI and to calculate synergy index (S), relative excess risk due to interaction (RERI), and attributable proportion due to interaction (API).ResultsAmong the 230 operational workers, the median blood aluminum concentration (P25, P75) was 40.11 (25.16, 58.89) µg·L−1, and there were 104 cases of abnormal urinary fluoride, with an abnormality rate of 45.2%. There was a multiplicative interaction (OR=7.783, 95%CI: 1.377, 43.991) and no additive interaction (RERI=0.030, 95%CI: −0.498, 0.559; API=0.018, 95%CI: −0.279, 0.316; S=1.049, 95%CI: 0.519, 2.118) for the effect between blood aluminum and urinary fluoride on overall cognitive function of the workers. The logistic regression analysis showed that the risk of MCI was 12.105 (95%CI: 2.802, 52.287) times higher in workers with both high blood aluminum and high urinary fluoride than in those with low blood aluminum and low urinary fluoride, after adjusting for selected influencing factors.ConclusionOccupational exposure related high blood aluminum and high urinary fluoride are risk factors for cognitive dysfunction, and the coexistence of both indicators increases the risk of MCI in workers with occupational aluminum exposure, with a multiplicative interaction.

Aluminum (Al) is a common neurotoxicant in the environment, but the molecular mechanism of its toxic effects is still unclear. Studies have shown that aluminum exposure causes an increase in neuronal apoptosis. The aim of this study was to investigate the mechanism and signaling pathway of neuronal apoptosis induced by aluminum exposure. The rat model was established by intraperitoneal injection of maltol aluminum for 90 days. The results showed that the escape latency of the three groups exposed to maltol aluminum was higher than that of the control group on the 3rd, 4th and 5th days of the positioning cruise experiment (P

Epidemiological studies from diverse global regions suggest a correlation between the accumulation of aluminum in the brain and the onset of various neurodegenerative diseases, including Alzheimer's disease, of which, neuronal cells death happen. Our previous research has found the potential of aluminum to induce neuronal cell death. A comprehensive exploration of the regulatory pathways influenced by aluminum in neuronal cell death could contribute to the development of strategies aimed at preventing the detrimental impact of aluminum on neuronal cells. This study is dedicated to exploring the impact of aluminum on mitochondrial homeostasis through the RIP3-PGAM5-Drp1 pathway, with a specific focus on its potential role in necroptosis. We observed that the inhibition of RIP3 function and the reduction in PGAM5 protein expression both mitigate aluminum-induced necroptosis in PC12 cells and enhance mitochondrial function. However, the inhibition of PGAM5 protein expression does not exert an impact on the expression of RIP3 and MLKL proteins. In summary, our study posits that aluminum can induce necroptosis in PC12 cells through the RIP3-PGAM5-Drp1 pathway.

BackgroundPrevious studies show that aluminum exposure could increase the expression of miRNA-134-3p, which is involved in the mechanism of aluminum induced learning and memory impairment. However, it has not been investigated whether the expression level of miRNA-134-3p in the peripheral blood of occupational aluminum exposed workers is related to the blood aluminum concentration yet.ObjectiveTo evaluate a potential correlation between aluminum concentration in peripheral blood and miR-134-3p expression in occupational aluminum exposed workers.MethodsA total of 184 male aluminum workers in the electrolytic aluminum workshop, aluminum oxide workshop, and thermal power workshop of an aluminum plant in Shanxi were selected by cluster sampling. They were divided into four groups (Q1-Q4) according to the quartiles of blood aluminum concentration, with 46 workers in each group. The basic information of workers was collected by questionnaire survey, and the cognitive function of workers was evaluated by Montreal Cognitive Assessment (MoCA). The plasma of workers was collected, and the relative expression level of miR-134-3p in plasma was detected by real-time quantitative polymerase chain reaction (RT-PCR). The plasma aluminum concentration was detected by inductively coupled plasma mass spectrometry (ICP-MS). The associations among workers' peripheral blood aluminum concentration, plasma miR-134-3p expression level, and total MoCA score were evaluated by generalized linear models.ResultsThe workers' medians (P25, P75) of blood aluminum concentration, plasma relative expression level of miR-134-3p, and MoCA score were 39.31 (25.30, 57.41) μg·L-1, 2.93 (2.29, 3.74), and 22.0 (20.0, 26.0), respectively. The results of the generalized linear model showed that after adjusting for age, body mass index, smoking, and alcohol consumption, compared with the Q1 group, blood aluminum in the Q2, Q3, or Q4 group had an impact on related plasma miR-134-3p expression level and total MoCA score (P0, Ptrend0.05).ConclusionOccupational aluminum exposure can lead to an increase in the expression level of miR-134-3p in plasma of workers, which may be related to a decrease in cognitive function of workers.

BackgroundOccupational aluminum exposure may associate with cognitive impairment in workers. At present, brain functional imaging data are not available for evaluating cognitive dysfunction in workers with occupational exposure to aluminum. The role of brain functional connectivity in cognitive decline associated with occupational aluminum exposure is not clear yet. ObjectiveTo explore potential mediating effect of brain functional connectivity value on cognitive decline induced by occupational aluminum exposure, to assess the relationship between cognitive impairment and brain functional connectivity, and to identify appropriate imaging evidence of early cognitive changes induced by occupational aluminum exposure. MethodsThis study used a subset data from a previous cross-sectional survey. Based on the data of aluminum-exposed workers, over 40 years old, aluminum-exposed working years >1 year, Montreal International Cognitive Assessment (MoCA) (Beijing version) score

BackgroundA large amount of iron deposition in the brain can cause neuronal damage by inducing oxidative stress, neuroinflammation, and abnormal mitochondrial function. In addition, iron deposition is also reported to be closely related to the pathogenesis of Alzheimer's disease (AD). The neurofibrillary tangles aggregated by tau hyperphosphorylation are one of the important pathological features of AD. ObjectiveTo investigate potential effect of exogenous trivalent iron ions on neuronal activity in human neuroblastoma (SH-SY5Y) cells and tau hyperphosphorylation and aggregation. MethodsSH-SY5Y cells were treated with ferric chloride (FeCl3) at four concentrations (10, 100, 200, and 400 mg·L−1). Cell survival rate was then detected by CCK8 assay. Intracellular iron content was determined prussian blue (Perl's) by iron staining after 24 h exposure to FeCl3 at 10 or 200 mg·L−1. Transfection of tau-P301L plasmid was conducted to construct an AD-like cell model for tau overexpression. The differences in the expression of the phosphorylated tau (p-tau) protein in SH-SY5Y cells and SH-SY5Y cells with tau overexpression were detected by Western blotting after 24 h exposure to FeCl3 at 10 and 200 mg·L−1. After dilution with phosphate buffered saline (PBS), FeCl3, human tauR3, and FeCl3 + tauR3 were incubated at 37℃, and the fluorescence intensity reflecting tau aggregation level was measured by thioflavin T(ThT) method at 12, 24, 36, 48, 60, 72, 84, and 96 h, respectively. Meanwhile, after 96 h coincubation of FeCl3 and tauR3, the fibers formed by tau aggregation were observed under a transmission electron microscope (TEM). ResultsAfter 24 h of FeCl3 exposure, the cell survival rate of SH-SY5Y cells among all groups was statistically different (F=8.63, P

Aluminium (Al) is a common environmental neurotoxin, but the molecular mechanism underlying its toxic effects remains unclear. Many studies have shown that aluminium exposure leads to increased neuronal apoptosis. This study aimed to investigate the mechanisms and signalling pathways involved in aluminium exposure-induced neuronal apoptosis. The results showed a decrease in the number of PC12 cells and changes in cell morphology in the aluminium maltol exposure group. The viability of PC12 cells decreased gradually with increasing of exposure doses, and the apoptosis rate increased. The expression of Lnc001209 decreased gradually with an increase in the aluminium exposure dose. After transfection of Lnc001209 siRNA in aluminium-exposed PC12 cells, the protein expression levels of p-Akt Ser473, p-Akt Thr308, p-P85 Tyr467, p-mTOR Ser2448 and CD36 were increased. RNA pull-down MS showed that Lnc001209 interacts with the CD36 protein. Expression of the CD36 protein was increased in PC12 cells exposed to aluminium. The results of the CD36 intervention experiment showed that the protein expression levels of p-Akt Ser473, p-Akt Thr308, p-P85 Tyr467, and p-mTOR Ser2448 likely increased after CD36 overexpression. In addition, the phosphorylation level of AKT had the most significant increase. The enhancement of p-Akt activity promotes neuronal apoptosis.

BackgroundOccupational aluminum exposure is closely related to cognitive impairment, and alcohol consumption is also closely related to cognitive dysfunction.ObjectiveTo explore the effects of types of alcohol consumption on cognitive function of occupational aluminum exposed workers.MethodsA total of 181 workers aged from 23 to 56 years were selected by cluster sampling method in an electrolytic aluminum workshop of an aluminum plant in a region and in a maintenance workshop of another plant in the same region from July to August, 2019. Venous blood was collected, and plasma aluminum concentration was determined by inductively coupled plasma mass spectrometry. The study subjects were divided into low and high exposure groups based on the median blood aluminum level and type of work. Their basic information was collected by occupational health examination. Workers' cognitive function was assessed using the Montreal Cognitive Assessment Scale-Beijing Edition. Logistic regression was used to analyze the association between plasma aluminum concentration and cognitive impairment, and between the types of alcohol consumption (including Baijiu, red wine, and beer) and cognitive impairment, Unconditional logistic regression was used to fit multiplicative interaction model as well as additive interaction model of plasma aluminum concentration and the types of alcohol consumption, and to calculate the relative excess relative risk due to interaction (RERI) and attributable proportion due to interaction (AP).ResultsThe M (P25, P75) concentrations of plasma aluminum were 40.01 (25.05, 60.56) µg·L−1 in the total study subjects, 25.16 (17.13, 34.78) µg·L−1 in the low exposure group and 60.56 (47.40, 68.53) µg·L−1 in the high exposure group. After adjusting the type of alcohol consumption, drinking, age, duration of exposure to aluminum, education, marital status, and smoking, the odds ratios for impairments of attention, language expression, and overall cognitive function in the high exposure group were 4.295 (95%CI: 1.912-9.648), 5.687 (95%CI: 1.355-23.867), and 2.720 (95%CI: 1.225-6.040) times of the low exposure group respectively. Besides, after adjusting blood aluminum concentration, total alcohol consumption, age, duration of exposure to aluminum, education, marital status, and smoking, the risk of attention impairment of the Baijiu drinkers was 2.613 (95%CI: 1.054 to 6.837) times of the non-Baijiu drinkers; the risks of impairment of visuospatial abilities and execution functions, language expression, delayed recall, and overall cognitive function of the beer drinkers were 3.165 (95%CI: 1.285-7.797), 17.898 (95%CI: 1.590-201.480), 3.118 (95%CI: 1.215-8.003), and 3.824 (95%CI: 1.736-8.423) times of the non-beer drinkers. There were both additive [RERI (95%CI): 1.745 (1.394-2.097), AP (95%CI): 0.415 (0.201-0.630)] and multiplicative (OR=3.591, 95%CI: 1.393-9.255) interactions between Baijiu intake and plasma aluminum concentration levels on the attention domain. The cognitive impairment attributed to the interactive effects of drinking Baijiu and plasma aluminum concentration in individuals with attention impairment accounted for 41.5%. There were both additive [RERI (95%CI): 5.955 (0.562-11.328), AP (95%CI): 0.829 (0.577-1.081)] and multiplicative (OR=42.174, 95%CI: 5.469-325.252) interactions between beer drinking and plasma aluminum concentration on the overall cognitive function. Among the individuals with overall cognitive impairment, the cognitive impairment caused by the interaction of beer drinking and plasma aluminum concentration accounted for 82.9%.ConclusionOccupation aluminum exposed workers' attention, language expression, and overall cognitive function are closely related to their plasma aluminum concentration. Plasma aluminum concentrations have interactions with Baijiu and beer consumption on cognitive impairment of workers.

The theory of the brain-gut axis has confirmed that gut microbiota and metabolites are involved in the progression of neurodegenerative diseases through multiple pathways. However, few studies have highlighted the role of gut microbiota in cognitive impairment induced by aluminum (Al) exposure and its correlations with the homeostasis of essential metal content in the brain. To explore the relationship between alterations in the content of essential metals in the brain and relative abundance changes in gut microbiota induced by Al exposure, the Al, zinc (Zn), copper (Cu), iron (Fe), chromium (Cr), manganese (Mn), and cobalt (Co) content level in the hippocampus, olfactory bulb, and midbrain tissue were measured by inductively coupled plasma mass spectrometry (ICP-MS) methods after Al maltolate was intraperitoneally injected every other day for exposed groups. Then the unsupervised principal coordinates analysis (PCoA) and linear discriminant analysis effect size (LEfSe) were used to analyze the relative abundance of the gut microbiota community and the structure of the gut microbiome. Finally, the correlations between gut microbiota composition and essential metal content in the different exposure groups were explored by using the Pearson correlation coefficient method. Based on the results, we indicated that the content of Al in the hippocampus, olfactory bulb, and midbrain tissue was increased and then decreased with the increasing exposure duration, with peaks occurring between 14 and 30 days. Concomitantly, Al-exposure decreased the Zn, Fe, and Mn levels in these tissues. 16 S rRNA gene sequencing results indicated that significant differences in the intestinal microbial community structure at the phylum, family, and genus levels were found in the Day 90 exposed group compared with the Day 7 exposed group. Ten enriched species in the exposed group were identified as markers at the three levels. Furthermore, ten bacteria at the genus level were identified to have a significantly strong correlation (r = 0.70–0.90) with Fe, Zn, Mn, and Co.

BackgroundAluminum can cause synaptic plasticity damage in the hippocampus, probably due to blocked interneuronal signal transmission. MicroRNA-29a (miR-29a) can target phosphatase and tensin homolog deleted on chromosome ten (PTEN) expression and participate in the generation of neuronal networks, and may be involved in the effect of aluminum on the electrical activity of neuronal networks.ObjectiveTo study the role and mechanism of miR-29a-targeted PTEN in aluminum-induced neuronal network injury in primary hippocampal neurons of ICR mice treated with maltol aluminum [Al(mal)3] in vitro.MethodsPrimary hippocampal neurons of ICR mice born within 24 h were cultured in vitro. The purity of neurons was determined by labeling neuron-specific microtubule-associated protein 2 (MAP2) by immunofluorescence staining on day six of the culture; neurons were treated with different concentrations of Al(mal)3, and divided into a control group, and 10, 20, and 40 μmol·L−1 Al(mal)3 groups, and neuronal cell viability was detected by CCK-8 method. Al(mal)3 at 20 μmol·L−1 was selected for subsequent experiments to establish a neuronal network injury model for intervention. The lentivirus infection method was used to transfect miR-29a into neurons, which were divided into mNG, mNG+20 μmol·L−1 Al(mal)3, miR-29a, and miR-29a+20 μmol·L−1 Al(mal)3 groups, and micro-electrode array (MEA) was used to analyze the firing of neuronal network. The expressions of miR-29a and PTEN mRNA in each group were detected by real-time PCR (RT-PCR), and the expression of PTEN protein in each group was detected by Western blotting.ResultsThe purity of primary mouse hippocampal neurons was greater than 90%, and the viability of the neurons was above 80% in all groups. At 48 h of the designed Al(mal)3 treatments, the changes in spike frequency, burst frequency, network burst frequency, and synchrony index of neurons cultivated on MEA plates in the control group were 207.56%±38.70%, 73.19%±46.43%, 75.42%±33.04%, and 117.13%±15.54%, respectively; the Al(mal)3 groups’ neuronal network electrical activity showed a decreasing trend. Compared with the control group, the spike frequency, burst frequency, network burst frequency, and synchrony index of the 20 and 40 μmol·L−1 Al(mal)3 groups significantly decreased (The changes were 171.70%±28.08%, 49.20%±23.23%, 50.20%±18.18%, and 85.45%±20.30%; 150.68%±26.15%, 43.43%±15.54%, 52.05%±26.31%, and 26.80%±8.29%, respectively, P < 0.05). Compared with the control group (1.00), the miR-29a relative expression levels were significantly decreased in the 20 μmol·L−1 Al(mal)3 group (0.74±0.09) and the 40 μmol·L−1 Al(mal)3 group (0.62±0.12) (P < 0.05); the relative expression levels of PTEN mRNA were significantly increased in the 20 μmol·L−1 Al(mal)3 group (1.32±0.12) and the 40 μmol·L−1 Al(mal)3 group (1.48±0.11) (P < 0.05); the PTEN protein relative expression levels (1.29±0.12 and 1.82±0.10, respectively) were also significantly increased (P < 0.05). By overexpressing miR-29a in mouse primary hippocampal neurons, the spike frequency, burst frequency, and network burst frequency were significantly higher in the miR-29a group compared with the mNG group (The changes were 252.80%±62.03%, 171.65%±56.30%, and 197.75%±27.12%, respectively, P

Aluminum is a known neurotoxin that can induce Aβ deposition and abnormal phosphorylation of tau protein, leading to Alzheimer disease (AD)-like damages such as neuronal damage and decreased learning and memory functions. In this study, we constructed a rat model of subchronic aluminum maltol exposure, and the whole-transcriptome sequencing was performed on the hippocampus of the control group and the middle-dose group. A total of 167 miRNAs, 37 lncRNAs, 256 mRNAs, and 64 circRNAs expression changed. The Kyoto Encyclopedia of Genes and Genomes showed that PI3K/AKT pathway was the most enriched pathway of DEGs, and IRS1 was the core molecule in the PPI network. circRNA/lncRNA-miRNA-mRNA networks of all DEGs, DEGs in the PI3K/AKT pathway, and IRS1 were constructed by Cytoscape. Molecular experiment results showed that aluminum inhibited the IRS1/PI3K/AKT pathway and increased the content of Aβ and tau. In addition, we also constructed an AAV intervention rat model, proving that inhibition of miR-96-5p expression might resist aluminum-induced injury by upregulating expression of IRS1. In general, these results suggest that the ceRNA networks are involved in the neurotoxic process of aluminum, providing a new strategy for studying the toxicity mechanism of aluminum and finding biological targets for the prevention and treatment of AD.

Nervous system is the most important system of human body. More and more neurotoxic chemicals are found to inflict effects on nervous system, causing cognitive impairment. In this overview, the neurotoxic effects of environmental factors and their relationship with neurodegenerative diseases are briefly introduced. Further, aiming at the damage to the nervous system caused by metals such as aluminum, manganese, and iron, this special column attempted to evaluate the damage degree by combining objective imaging and cognitive scales and to explore the mechanism of toxicity (including neurotransmitter secretion disorders and tau protein hyperphosphorylation) by in vitro experiments. These papers also introduced intervention studies using hydrogen-rich water to target the damage of ionizing radiation to the nervous system and discussed the intervention mechanism as modulating the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/Caspase-9 pathway, and Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway.

BackgroundAluminum can induce irreversible structural and synaptic functional damage, and the associated mechanism may be related to the neurite damage regulated by glycogen synthase kinase-3β (GSK-3β)/collapsin response mediator protein 2 (CRMP2).ObjectiveThis experiment is conducted to investigate the effect of aluminum-maltolate [Al(mal)3] on primary hippocampal neuron neurites in mice, and reveal the role of GSK-3β-CRMP2 in this process.MethodsThe hippocampus of newborn ICR mice (≤ 24 h old) was used for primary neuronal cultures. On the 5th day in vitro (DIV5), neuron purity detection were performed by confocal laser scanning microscopy. On DIV7, the neurons were transfected with lentiviral vector-mediated mNeonGreen. On DIV10, the neurons with mNeonGreen fluorescence in good growth state were treated with Al(mal)3. The stage I experimental groups were blank control group, maltol group, 10 µmol·L−1 Al group, 20 µmol·L−1 Al group, and 40 µmol·L−1 Al group. Then 20 µmol·L−1 Al was used to establish a model of neurite injury and for the intervention. The stage II experimental groups were blank control group, dimethyl sulfoxide (DMSO) group, Al (20 µmol·L−1) group, SB (GSK-3β inhibitor, 1 µmol·L−1), and SB (1 µmol·L−1)+Al (20 µmol·L−1) group. CCK-8 method was used to detect the viability of neurons. The primary hippocampal neurons of mice were scanned with high content analysis system at 0 h and 48 h after Al or SB treatment, and the density and length of neurites were analyzed. Western blotting was used to detect the expression and phosphorylation levels of CRMP2 and GSK-3β in primary hippocampal neurons of mice.ResultsThe immunofluorescence results showed that the purity of primary neurons was more than 90%. Compared with the blank control group in stage I, the cell viability rates of the 10, 20, and 40 µmol·L−1 Al groups were decreased after 48h of Al(mal)3 treatment (P

Benzo[a]pyrene (B[a]P) is a widespread carcinogenic pollutant in the environment. Although previous studies have demonstrated the neurodevelopmental toxicity of B[a]P, the precise mechanisms underlying the neurotoxic effects induced by prenatal B[a]P exposure remain largely unknown. In the present study, pregnant Sprague-Dawley (SD) rats were injected intraperitoneally with 0, 10, 20, or 40 mg/kg-bw of B[a]P for three consecutive days on embryonic days 17–19. The learning and memory abilities of offspring were determined by Morris Water Maze (MWM) test, while the number of dendritic branches and the density of dendritic spines in hippocampal CA1 and DG regions were evaluated by Golgi-Cox staining at PND 45 and PND 75. The mRNA expression of BDNF, PSD-95, and SYP in offspring hippocampus were detected by qRT-PCR, and the protein expression of BDNF, PSD-95, SYP, HDAC2, acH3K9, and acH3K14 were measured by Western blotting or immunohistochemistry. CHIP-PCR was performed to further detect the levels of acH3K9 and acH3K14 in the promoter regions of BDNF and PSD-95 genes. Our results showed that rats prenatally exposed to B[a]P exhibited impaired spatial learning and memory abilities and the number of dendritic branches and the density of dendritic spines in the hippocampal CA1 and DG regions were significantly reduced during adolescence and adulthood. The expression of HDAC2 protein was significantly upregulated, while acH3K9, acH3K14, BDNF, PSD-95, and SYP protein levels were significantly downregulated in the hippocampus of B[a]P- exposed rats. In addition, CHIP results showed that prenatal B[a]P exposure markedly decreased the level of acH3K9 and acH3K14 in the promoter region of BDNF and PSD-95 gene in the hippocampus of PND 45 and PND 75 offspring. All of the results suggest that prenatal B[a]P exposure impairs cognitive function and hippocampal synaptic plasticity of offspring in adolescence and adulthood, and HDAC2-mediated histone deacetylation plays a crucial role in these deficits.

We previously reported that aluminum (Al) can cause a range of neurotoxic injuries including progressive irreversible synaptic structural damage and synaptic dysfunction, and eventually neuronal deaths. Mechanism of Al-induced electrophysiological and neuronal connectivity changes in neurons may indicate damage to the neuronal network. Here, mouse primary hippocampal neurons were cultured on micro-electrode array (MEA)- and high-content analysis (HCA)-related plates, showing that Al exposure significantly inhibited hippocampal neuronal electrical spike activity and neurite outgrowth characterized by a reduction in neurite branching and a decrease in the average total neurite length in relation to both Al dose and time of incubation. In recent years, miR-29a/ phosphatase and tensin homolog (PTEN) have been found to play pivotal roles in the morphogenesis of neurons, it has been confirmed in vitro and in vivo that the PTEN–Glycogen synthase kinase-3β (GSK-3β) axis regulates neurite outgrowth. The present study demonstrated that increases in Al exposure and dose gradually reduce miR-29a expression. Up-regulation of miR-29a in the hippocampal neurons by lentivirus transfection reversed the decrease in electrical spike activity and the reduction in both neurite branching and length induced by Al. Moreover, miR-29a suppressed the expression of PTEN and increased the level of phosphorylated Protein Kinase B (p-AKT) and p-GSK-3β which were inhibited by the Al treatment. This suggests that miR-29a is critically involved in the functional and structural neuronal damage induced by Al and is a potential target for Al neurotoxicity. Moreover, the reduction of neurite length and branching induced by Al exposure was regulated by miR-29a and its target neuronal PTEN–GSK3β signaling pathway, which also represents a possible mechanism of Al-induced the inhibition of the electrical activity. Collectively, Al-induced damage to the neuronal network occurred through miR-29a-mediated alterations of the PTEN–GSK3β signaling pathway.

Abstract Background Naphthalene is the simplest polycyclic aromatic hydrocarbon (PAH). It is easily emitted into the atmosphere, posing a significant risk to human health. However, limited studies have described the impact of naphthalene exposure on birth outcomes. In this study, we investigated the association between the maternal urinary metabolites of naphthalene, 2-hydroxynaphthalene (2-OH NAP), and birth outcomes. Method In the present study, four urinary PAH metabolites were measured in 263 pregnant women during late pregnancy. Multiple linear regression analysis was used to analyze the relationship between the concentrations of 2-OH NAP and birth outcomes, and restricted cubic spline models were further used to examine the shapes of the dose-response association. Result General linear models showed that prenatal urinary 2-OH NAP was associated with lower birth weight (BW) (− 4.38% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.049) and higher cephalization index (CI) (4.30% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.038). These associations were linear and significant when 2-OH NAP was modeled as a continuous variable in restricted cubic spline models (P linear = 0.0293 for 2-OH NAP and BW; P linear = 0.0326 for 2-OH NAP and CI). Multiple linear regression data indicated that each 1 ln-unit increase in 2-OH NAP was significantly associated with a 2.09 g/cm increase in the CI. The associations among 2-OH NAP, BW, and CI were also observed in a subset of participants residing close to arterial traffic. Conclusion Our data indicated that prenatal exposure to naphthalene had an adverse effect on fetal birth outcomes, especially the brain development index. Reduced exposure to naphthalene may improve newborn health outcomes. In Taiyuan, naphthalene may result from traffic pollution.

Background: Previous studies have shown that multiple imbalances of metal ions in the brain are closely associated with the neurodegenerative disorders. Our studies have shown that long-term working exposure to aluminum induces increased plasma aluminum levels and causes cognitive impairment in workers at aluminum factories. Objective: To explore the levels of nine metals in plasma and the effect on cognitive function among in-service workers. Methods: In this cross-sectional study, cognitive function was assessed using the Montreal Cognitive Assessment (MoCA), which included seven subitems: executive/visuospatial abilities; naming; attention and calculation; language; abstract; recall; and orientation. The plasma levels of nine kinds of metals were measured by inductively coupled plasma-mass spectrometry (ICP-MS). A multivariate generalized linear regression model and Bayesian kernel machine regression (BKMR) were selected to estimate the relationship between metal plasma level and MoCA scores with adjustment for confounders. Results: One hundred and eighty-seven workers participated in this study. In the multivariable generalized linear model, among these nine metals studied, five were related to the MoCA score: aluminum, lithium, cobalt, zinc and chromium. In the BKMR model, a significantly negative correlation between the plasma aluminum, lithium and the total MoCA score was observed. Moreover, for subitems on the MoCA scale, the plasma levels of lithium, aluminum, and zinc had a significant correlation with the executive/visuospatial abilities, naming, and orientation abilities, respectively. The log-transformation concentrations of plasma aluminum and lithium were negatively correlated with the executive/visuospatial abilities and naming abilities, respectively. The log-transformation plasma zinc concentration was positively correlated with orientation abilities. Conclusion: Based on the results, we determined that increased aluminum and lithium and decreased zinc levels in plasma were associated with the incidence of mild cognitive impairment (MCI) in workers at a Chinese aluminum plant.

ObjectivesTo investigate the prevalence of mild cognitive impairment and the relationship with plasma aluminium among aluminium workers.DesignThis was a cross-sectional case-control study in the SH Aluminium Factory, China.SettingThe university and affiliated hospital cooperated in the study.ParticipantsThere 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 measuresBlood 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.ResultsAmong 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.ConclusionsMild 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.

Background: TiO2 nanoparticles (TiO2 NPs) are the nanomaterial most produced as an ultraviolet (UV) filter. However, TiO2 is a semiconductor and, in nanoparticle size, is a strong photocatalyst, raising concerns about photomutagenesis. Mesoporous silica nanoparticles (MSN) were synthetized incorporating TiO2 NPs (TiO2@MSN) to develop a cosmetic UV filter. The aim of this study was to assess the toxicity of TiO2@MSN, compared with bare MSN and commercial TiO2 NPs, based on several biomarkers. Materials and Methods: Human peripheral blood mononuclear cells (PBMC) were exposed to TiO2@MSN, bare MSN (network) or commercial TiO2 NPs for comparison. Exposed PBMC were characterized for cell viability/apoptosis, reactive oxygen species (ROS), nuclear morphology, and cytokines secretion. Results: All the nanoparticles induced apoptosis, but only TiO2 NPs (alone or assembled into MSN) led to ROS and micronuclei. However, TiO2@MSN showed lower ROS and cytotoxicity with respect to the P25. Exposure to TiO2@MSN induced Th2-skewed and pro-fibrotic responses. Conclusions: Geno-cytotoxicity data indicate that TiO2@MSN are safer than P25 and MSN. Cytokine responses induced by TiO2@MSN are imputable to both the TiO2 NPs and MSN, and, therefore, considered of low immunotoxicological relevance. This analytical assessment might provide hints for NPs modification and deep purification to reduce the risk of health effects in the settings of their large-scale manufacturing and everyday usage by consumers.

Alumina nanoparticles (AlNP) have been shown to accumulate in organs and penetrate biological barriers which lead to toxic effects in many organ systems. However, it is not known whether AlNP exposure to female mice during pregnancy can affect the development of the central nervous system or induce neurodevelopmental toxicity in the offspring. The present study aims to examine the effect of AlNP on neurodevelopment and associated underlying mechanism. ICR strain adult female mice were randomly divided into four groups, which were treated with normal saline (control), 10 μm particle size of alumina (bulk-Al), and 50 and 13 nm AlNP during entire pregnancy period. Aluminum contents in the hippocampus of newborns were measured and neurodevelopmental behaviors were tracked in the offspring from birth to 1 month of age. Furthermore, oxidative stress and neurotransmitter levels were measured in the cerebral cortex of the adolescents. Our results showed that aluminum contents in the hippocampus of newborns in AlNP-treated groups were significantly higher than those in bulk-Al and controls. Moreover, the offspring delivered by AlNP-treated female mice displayed stunted neurodevelopmental behaviors. Finally, the offspring of AlNP-treated mice demonstrated significantly increased anxiety-like behavior with impaired learning and memory performance at 1 month of age. The underlying mechanism could be related to increased oxidative stress and decreased neurotransmitter levels in the cerebral cortex. We therefore conclude that AlNP exposure of female mice during pregnancy can induce neurodevelopmental toxicity in offspring.

Since 2000, the government in Shanxi province has mounted several initiatives and mandated factory shutdowns with the goal of reducing coal burning emissions and the environmental impacts of industrialization. We estimated the health benefits associated with air quality improvement from 2001 to 2010 in Taiyuan, Shanxi Province, using disability-adjusted life years (DALYs) and monetized the health benefits using value of statistical life (VOSL). Data were collected on annual average concentrations of particulate matter less than 10 μm in aerodynamic diameter (PM10) and relevant health outcomes in Taiyuan from 2001 to 2010. Selected exposure–response functions were used to calculate the cases of death or disease attributable to PM10 annually over a 10-year period. These were summed to calculate the DALYs lost and their monetary value associated with PM10 each year between 2001 and 2010. Air quality improvement from 2001 to 2010 was estimated to have prevented 2810 premature deaths, 951 new cases of chronic bronchitis, 141,457 cases of outpatient visits, 969 cases of emergency-room visits and 31,810 cases of hospital admissions. The DALYs (VOSL) decreased by 56.92% (52.68%) from 52,937 (7274 million Yuan) in 2001 to 22,807 (3442 million Yuan) in 2010. Premature deaths accounted for almost 95% of the total DALYs. Our analysis demonstrates that air pollution abatement during the last decade in Taiyuan has generated substantial health benefits. Keywords: Air pollution, Particulate matter, Health benefits, Disability-Adjusted Life Years, Value of statistical life

There is concern about the possible toxicity of palladium nanoparticles (Pd-NP), as they are released in the environment through many applications. We previously studied the toxicity of Pd-NP at high concentrations; here we address the possible toxicity of Pd-NP at low, subtoxic doses. In particular, we have exposed normal human PBMC entering into the first in vitro mitotic division to Pd-NP and to Pd(IV) ions to evaluate ROS generation and cell cycle progression. We have measured a statistically significant increase of intracellular ROS in Pd(IV) exposed cells, but not in Pd-NP exposed cells. TEM revealed accumulation of lipid droplets and autophagic and mitophagic vacuoles, which appeared more conspicuous in cells exposed to Pd(IV) ions than to Pd-NP. Pd-NP were visible in the cytoplasm of Pd-NP exposed cells. Pd-NP addition was associated with a significant increase of cells within the G0/G1-phase and a significant reduction in GS- and G2/M-phases. Cells exposed to Pd(IV) ions showed a significant amplification of these cell cycle alterations. These results suggest that ions, per se or released by NPs, are the true inducers of Pd toxicity. It will be essential to verify whether the observed disturbance represents a temporary response or might result in permanent alterations.