Environmental exposure to manganese and health risk assessment from personal sampling near an industrial source of airborne manganese

Development of a novel NIR-II fluorescence probe for monitoring serum albumin fluctuation in cerebra neurotoxicity induced by manganese exposure

Manganese is essential for various biological functions; however, excessive exposure can lead to significant health risks, particularly brain neurotoxicity. Understanding manganese-induced alterations in brain serum protein levels and brain function is crucial for elucidating the mechanisms underlying manganese neurotoxicity. To address this, we developed a novel NIR-II fluorescent probe, RSM, characterized by robust binding to serum albumin and high sensitivity. Using RSM, we observed that heightened BSA uptake in cells exposed to elevated manganese concentrations relative to those exposed to lower levels. Furthermore, we successfully detected changes in serum albumin levels induced by manganese neurotoxicity in brain tissue through in situ NIR-II fluorescence imaging. Our findings establish an association between augmented manganese-induced neurotoxicity and elevated serum albumin content in the brain. This work provides a valuable tool for further investigating the mechanisms of toxic molecules.

Association between some environmental risk factors and attention-deficit hyperactivity disorder among children in Egypt: a case-control study

BACKGROUND

Attention-Deficit Hyperactivity Disorder (ADHD) is a complex disease that negatively impacts the social and academic/occupational activities of children and is more common in boys than in girls.

METHODS

This case-control study aimed to assess the association between some environmental risk factors and ADHD among children in Alexandria, Egypt. It was carried out at the outpatient clinics of El Shatby Pediatric University Hospital in Alexandria, Egypt, with 252 children (126 cases and 126 controls). Hair samples were collected for analysis of lead and manganese levels using Atomic Absorption Spectrophotometer. A pre-designed interview questionnaire was used to determine the important environmental risk factors that may be related to ADHD.

RESULTS

Children from parents with low levels of education, living in crowded houses, and occupational exposure to chemical agents were found to be risk factors for ADHD. The mean ± SD hair lead level in ADHD children was 2.58 ± 1.95, while in controls was 1.87 ± 0.92, with a statistically significant difference (p < 0.001). The mean ± SD hair manganese level in ADHD children was 2.10 ± 1.54, while in controls was 1.11 ± 0.69, with a statistically significant difference (p < 0.001). The logistic regression model revealed that six factors had a significant association with ADHD: using of newspapers to wrap food 3 or more times a week (adjusted odds ratio (AOR) = 105.11, 95% CI: 11.18-988.26), daily TV watching by child for more than 5 h (AOR = 63.96, 95% CI: 2.56-1601.32), child's eating commercially packed noodles 3 times or more per week (AOR = 57.73, 95% CI: 3.77-593.93), using unpackaged flour in cooking (AOR = 44.47, 95% CI: 1.83-629.80), eating sweets daily by child (AOR = 6.82, 95% CI: 1.23-37.94), and lastly elevated hair Manganese level (AOR = 3.57, 95% CI: 1.24-10.29).

CONCLUSIONS

ADHD is a multi-factorial disorder, where many environmental risk factors contribute to its development. Future efforts to determine the best preventive strategy in Egypt must be based on a better knowledge of the role of environmental risk factors in the etiology of the disorder. Eliminating non-essential uses of lead and providing public education regarding the importance of safe disposal of lead-acid batteries and computers are necessary.

Manganese pollution in eastern India causing cancer risk

Groundwater poisoning by heavy metals has caused serious health hazards in the exposed population globally. Manganese (Mn) poisoning causing human health hazards is very meagerly reported worldwide. The present research elucidates for the first time the catastrophic effect of manganese causing cancer in the Gangetic plains of Bihar (India). The blood samples of n = 1146 cancer patients were voluntarily obtained for the study, after their consent. Their household water samples were also collected for the study. All the samples were analysed for Mn contamination by Atomic Absorption Spectrophotometer. The study indicates high Mn contamination in the cancer patient blood samples with highest content as 6022 µg/L. Moreover, the cancer patient's household handpump water samples also contained elevated Mn contamination. The correlation coefficient study finds significant association between Mn contamination in blood of cancer patients and their handpump water. The carcinoma group of cancer patients mostly in Stage III & IV had significant Mn contamination in their blood (above WHO/BIS permissible limit). The geospatial study depicts Mn contamination in handpump water in the state of Bihar in correlation with cancer patient's blood samples. This novel finding is being reported in India for the first time, which correlates cancer with handpump drinking water. The long-term Mn exposure could be one of the causative agents for elevating cancer incidences. However, other confounding risk factors cannot be denied.

Targeting m6A mRNA demethylase FTO alleviates manganese-induced cognitive memory deficits in mice

Manganese (Mn) induced learning and memory deficits through mechanisms that are not fully understood. In this study, we discovered that the demethylase FTO was significantly downregulated in hippocampal neurons in an experimental a mouse model of Mn exposure. This decreased expression of FTO was associated with Mn-induced learning and memory impairments, as well as the dysfunction in synaptic plasticity and damage to regional neurons. The overexpression of FTO, or its positive modulation with agonists, provides protection against neurological damage and cognitive impairments. Mechanistically, FTO interacts synergistically with the reader YTHDF3 to facilitate the degradation of GRIN1 and GRIN3B through the m6A modification pathway. Additionally, Mn decreases the phosphorylation of SOX2, which specifically impairs the transcriptional regulation of FTO activity. Additionally, we found that the natural compounds artemisinin and apigenin that can bind molecularly with SOX2 and reduce Mn-induced cognitive dysfunction in mice. Our findings suggest that the SOX2-FTO-Grins axis represents a viable target for addressing Mn-induced neurotoxicity and cognitive impairments.

The association of manganese overexposure and neurobehavioral function is moderated by arsenic: A metal mixture analysis of children living near coal ash storage sites

Manganese is an essential element but can be neurotoxic if overexposed. Our previous study found that a higher level of manganese in nail biomarkers from children living near coal ash storage sites was associated with poorer neurobehavioral function. Children living near this type of pollution may be exposed to other metal neurotoxicants and a better understanding of manganese in the context of multiple exposures is needed. Mixture analyses were completed using nail samples from 251 children aged 6-14 years old. These biomarkers containing metals known to impact brain functioning were investigated to test our hypothesis that a mixture of metals including manganese impacts the development of children living near coal ash sites. Nails collected from children were analyzed using ICP-MS for manganese, arsenic, cadmium, lead, and zinc based on previous research on neurotoxicity. Bayesian kernel machine regression (BKMR) was used while adjusting for age, sex, and maternal education as potential covariates. Children also completed the Behavioral Assessment Research System (BARS) to provide neurobehavioral measures of attention and processing speed as outcomes for mixture analyses. Metal mixture analyses indicated that the relationship of manganese concentration and attention and processing speed was moderated by arsenic.,. When nail biomarkers for arsenic were highest (90th percentile), manganese was associated with poorer neurobehavioral performance on the BARS, measured by CPT hit latency. At low levels of arsenic (10th percentile), there was no evidence of harmful effects from overexposure to manganese on CPT hit latency based on BKMR analysis. Previously reported effects of manganese on neurobehavioral function may be moderated by arsenic exposure. Metal exposures and behavior outcomes can be studied with mixture analyses such as BKMR to evaluate effects of simultaneous exposures on children exposed to pollution.

A critical review on bioremediation technologies of metal(loid) tailings: Practice and policy

Globally, most high-grade ores have already been exploited. Contemporary mining tends to focus on the extraction of lower-grade ores thereby leaving large stored tailings open to the environment. As a result, current mines have emerged as hotspots for the migration of metal(loid)s and resistance genes, thereby potentially contributing to a looming public health crisis. Therefore, the management and remediation of tailings are the most challenging issues in environmental ecology. Bioremediation, a cost-effective solution for the treatment of multi-element mixed pollution (co-contamination), shows promise for the restoration of mine tailings. This review focuses on the bioremediation technologies developed to untangle the issues of non-ferrous metal mine tailings. These technologies address the environmental risks of multi-element exposure to the ecosystem and human health risks. It provides a review and comparison of current bioremediation technologies used to mineralize metal(loid)s. The role of plant-microorganisms and their mechanisms in the remediation of tailings are also discussed. The importance of "treating waste with wastes" is crucial for advancing bioremediation technologies. This approach underscores the potential for waste materials to contribute to environmental cleanup processes. The concept of a circular economy is pertinent in this context, emphasizing recycling and reuse. There's an immediate need for international collaboration. Collaboration is needed in policy-making, funding, and data accessibility. Sharing data is essential for the growth of bioremediation globally.

Forced expression of microRNA-221-3p exerts protective effects against manganese-induced cytotoxicity in human lung epithelial cells

Manganese (Mn)-induced pulmonary toxicity and the underlying molecular mechanisms remain largely enigmatic. Further, in recent years, microRNAs (miRNAs) have emerged as regulators of several pollutants-mediated toxicity. In this context, our study aimed at elucidating whether miRNAs are involved in manganese (II) chloride (MnCl2) (Mn2+)-induced cytotoxicity in lung epithelial cells. Growth inhibition of Mn2+ towards normal human bronchial epithelial (BEAS-2B) and adenocarcinomic human alveolar basal epithelial (A549) cells was analyzed by MTT assay following 24 or 48 h treatment. Reactive oxygen species (ROS) generation, mitochondrial membrane potential (ΔΨm), cell cycle arrest, and apoptosis were evaluated by flow cytometry. RT-qPCR and Western blot were performed to analyze the expression of cyclins, anti-oxidant genes, and miRNAs. We used small RNA sequencing to investigate Mn2+-induced changes in miRNA expression patterns. In both cell lines, Mn2+ treatment inhibited growth in a dose-dependent manner. Further, compared with vehicle-treated cells, Mn2+ (250 μM) treatment induced ROS generation, cell cycle arrest, apoptosis, and decreased ΔΨm as well as altered the expression of cyclins and anti-oxidant genes. Sequencing data revealed that totally 296 miRNAs were differentially expressed in Mn2+-treated cells. Among them, miR-221-3p was one of the topmost down-regulated miRNAs in Mn2+-treated cells. We further confirmed this association in A549 cells. In addition, transient transfection was performed to study gain-of-function experiments. Forced expression of miR-221-3p significantly improved cell viability and reduced Mn2+-induced cell cycle arrest and apoptosis in BEAS-2B cells. In conclusion, miR-221-3p may be the most likely target that accounts for the cytotoxicity of Mn2+-exposed lung epithelial cells.