Features and patterns of changes in neurochemical parameters at different stages of chronic mercury intoxication

Introduction. At present, the features of the clinical picture and pathogenesis of the formation and progression of chronic intoxication under the influence of mercury remain insufficiently studied. Purpose. To study the features and patterns of changes in the neurotransmitters and neurotrophic factors concentration at different stages of chronic mercury intoxication (CMI). Materials and methods. A cohort examination of 69 workers (group 1) exposed to mercury, 18 individuals in the initial period of CMI (group 2), and 55 patients in the long-term period (group 3) were carried out. The content of neurotransmitters and neurotrophic factors was determined by enzyme immunoassay. The statistical processing included Wilcoxon, Kruskal-Wallis and Mann-Whitney tests. Results. Higher levels of histamine were found in group 2, low levels of metanephrine in group 1, and normetanephrine in group 3. An increase in the BDNF concentration was revealed in group 2 compared with groups 1 and 3. The content of neurotrophin-3 in group 3 was statistically significantly lower than in group 2. Conclusion. The general pattern for all stages is an increase in the norepinephrine and CNTF concentration. Mercury neurointoxication at all stages is characterized by high serotonin levels. A distinctive feature for trained workers is a compensatory increase in the normetanephrine level and a low BDNF and NT-3. For the initial period of CMI, an increase in the histamine, BDNF and NT-3 content is characteristic. The long-term period is characterized by an imbalance in the concentration of the studied neurotransmitters and neurotrophic factors.

From Molecules to Behavior in Long-Term Inorganic Mercury Intoxication: Unraveling Proteomic Features in Cerebellar Neurodegeneration of Rats

Mercury is a severe environmental pollutant with neurotoxic effects, especially when exposed for long periods. Although there are several evidences regarding mercury toxicity, little is known about inorganic mercury (IHg) species and cerebellum, one of the main targets of mercury associated with the neurological symptomatology of mercurial poisoning. Besides that, the global proteomic profile assessment is a valuable tool to screen possible biomarkers and elucidate molecular targets of mercury neurotoxicity; however, the literature is still scarce. Thus, this study aimed to investigate the effects of long-term exposure to IHg in adult rats’ cerebellum and explore the modulation of the cerebellar proteome associated with biochemical and functional outcomes, providing evidence, in a translational perspective, of new mercury toxicity targets and possible biomarkers. Fifty-four adult rats were exposed to 0.375 mg/kg of HgCl2 or distilled water for 45 days using intragastric gavage. Then, the motor functions were evaluated by rotarod and inclined plane. The cerebellum was collected to quantify mercury levels, to assess the antioxidant activity against peroxyl radicals (ACAPs), the lipid peroxidation (LPO), the proteomic profile, the cell death nature by cytotoxicity and apoptosis, and the Purkinje cells density. The IHg exposure increased mercury levels in the cerebellum, reducing ACAP and increasing LPO. The proteomic approach revealed a total 419 proteins with different statuses of regulation, associated with different biological processes, such as synaptic signaling, energy metabolism and nervous system development, e.g., all these molecular changes are associated with increased cytotoxicity and apoptosis, with a neurodegenerative pattern on Purkinje cells layer and poor motor coordination and balance. In conclusion, all these findings feature a neurodegenerative process triggered by IHg in the cerebellum that culminated into motor functions deficits, which are associated with several molecular features and may be related to the clinical outcomes of people exposed to the toxicant.

Evaluation of oxidative stress biomarkers in acute mercury intoxication

Objective:&nbsp;Very few studies have evaluated the association between mercury exposure and oxidative stress in humans, particularly in children. This is the first report where we aimed to determine the oxidative stress status of children who were accidently exposed to elemental mercury. Methods: In the present study, the study group was composed of 86 randomly selected children poisoned by mercury; the control group was composed of 78 children who had no history of mercury exposure. At admission, blood samples were collected. Blood superoxide dismutase activity, catalase enzyme activity, and glutathione peroxidase activity were measured by Fridovich, Beutler, and Lawrence Burk methods respectively, and the results were given as U/g Hb . Malondialdehyde level was measured by Ohkawa methods , and the results were given as mmol/ml. Results:&nbsp;Catalase levels were significantly lower in the patient group compared to the control group (1.28&plusmn;0.62 vs 3.90 &plusmn; 0.86 U/g Hb, p<0.01). In exposed children, SOD levels were significantly higher than the controls (5936 &plusmn; 810 vs 2226 &plusmn; 464 U/g Hb, p<0,05), while the GPx activity was significantly lower (13.01 &plusmn; 3.21&nbsp; vs 34.97 &plusmn; 7.32 U/g Hb, p<0.01). The MDA levels of the mercury group were significantly higher than the MDA levels of the control group (2.85&plusmn;0.84&nbsp; vs 2.05&plusmn;0.79 mmol/ml, p<0.05) . Conclusion: The results of the present study showed that acute mercury poisoning causes alteration of oxidative stress status in children exposed to elemental mercury.

Transdisciplinary Online Health Assessment of an Artisanal and Small-Scale Gold Mining Community during the COVID-19 Pandemic in the Mandalay Region of Myanmar

Artisanal and small-scale gold mining (ASGM) has a known negative effect on the community’s health; therefore, assessment to monitor community health is essential to detect any issues and enable early treatment. Because ASGM-related health issues are complex and cannot be addressed effectively with a traditional one-time health assessment alone, both long-term and regular health assessments using a transdisciplinary approach should be considered. In response to this need, we designed an online health assessment tool as a reference for a future long-term health assessment system. An online video interview was conducted with 54 respondents living in the ASGM area of Chaung Gyi Village, Thabeikkyin Township, Mandalay Region, Myanmar, via a social networking service application. The tool was used to evaluate community health during the coronavirus 2019 pandemic, including mercury intoxication symptoms, mining-related diseases, and other diseases. Results show that persons working in mining versus non-mining occupations had a greater prevalence of pulmonary diseases, such as pulmonary tuberculosis, silicosis, and bronchial asthma, in addition to malaria. Based on these findings, online health assessment using a transdisciplinary approach can be recommended as an effective tool for sustainable and long-term health assessment of ASGM-related disease and should be performed regularly following physical health surveys.

BIOLOGICAL MONITORING OF WORKERS EXPOSED TO MERCURY AND ITS COMPOUNDS

Biological monitoring is used to assess the toxic effect of mercury on the human body and to identify risk groups for the development of mercury intoxication at various stages of clinical and laboratory examination of workers who have contact with mercury vapor. A comprehensive analysis of changes in the biomarkers of exposure and effect in the conditions of professional exposure to mercury on the body of workers allows us to identify groups at increased risk of developing health disorders and optimize therapeutic and preventive measures taking into account the individual characteristics of the body. Biological monitoring should be implemented at the stage of preliminary, periodic medical examinations and in-depth examination of workers in contact with mercury vapor. Correlation and regression analysis of the data obtained showed a significant positive relationship between the average concentration of mercury in the air of the working area and the average concentration of mercury in the urine of the main occupational groups of mercury production workers.

Ocular Surface Pathology in Patients Suffering from Mercury Intoxication

Purpose: To report the ocular surface pathology of patients suffering from acute/subacute mercury vapor intoxication. Design: Cross-sectional study. Participants: Male workers intoxicated with inorganic mercury referred for ophthalmic involvement and healthy control subjects. Methods: The following tests were performed: dry eye (DE)-related symptoms indicated by the ocular surface disease (OSDI) index questionnaire; tear osmolarity; analysis of 23 tear cytokine concentrations and principal component and hierarchical agglomerative cluster analyses; tear break-up time (T-BUT); corneal fluorescein and conjunctival lissamine green staining; tear production by Schirmer and tear lysozyme tests; mechanical and thermal corneal sensitivity (non-contact esthesiometry); and corneal nerve analysis and dendritic cell density by in vivo confocal microscopy (IVCM). Results: Twenty-two out of 29 evaluated patients entered the study. Most had DE-related symptoms (OSDI values > 12), that were severe in 63.6% of them. Tear osmolarity was elevated (>308 mOsms/L) in 83.4% of patients (mean 336.23 (28.71) mOsm/L). Corneal and conjunctival staining were unremarkable. T-BUT was low (<7 s) in 22.7% of patients. Schirmer test and tear lysozyme concentration were low in 13.6% and 27.3% of cases, respectively. Corneal esthesiometry showed patient mechanical (mean 147.81 (53.36) mL/min) and thermal thresholds to heat (+2.35 (+1.10) °C) and cold (−2.57 (−1.24) °C) to be significantly higher than controls. Corneal IVCM revealed lower values for nerve density ((6.4 (2.94) n/mm2), nerve branching density (2 (2.50) n/mm2), and dendritic cell density (9.1 (8.84) n/mm2) in patients. Tear levels of IL-12p70, IL-6, RANTES, and VEGF were increased, whereas EGF and IP-10/CXCL10 were decreased compared to controls. Based on cytokine levels, two clusters of patients were identified. Compared to Cluster 1, Cluster 2 patients had significantly increased tear levels of 18 cytokines, decreased tear lysozyme, lower nerve branching density, fewer dendritic cells, and higher urine mercury levels. Conclusions: Patients suffering from systemic mercury intoxication showed symptoms and signs of ocular surface pathology, mainly by targeting the trigeminal nerve, as shown by alterations in corneal sensitivity and sub-basal nerve morphology.

Diagnostic value of IL-17 in neurointoxication with mercury

It is known that sufficient changes are observed in cellular and humoral links of immune system upon chronic exposure vapors of metallic mercury. In previous studies, upon development and in the course of the chronic mercury intoxication (CMI) we revealed pronounced regular changes of inflammatory mediators (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, TNFα), and showed an important role of autoimmune reactions affecting nervous tissue proteins. Over last 20 years, an increased interest was shown for interleukin 17 (IL-17) and its role in a number of inflammatory and autoimmune diseases. However, there is no data on its role in neurointoxication with mercury. Considering that IL-17 has proinflammatory activity and stimulates production of the individual cytokines, the goal of our work at the next stage of research, was to identify quantitative changes of serum IL-17 in patients with mercury neurointoxication of various severity, aiming to substantiate additional criteria for early and effective diagnosis of the disease.The study was performed in males chronically exposed to metallic mercury vapors with early signs of neurointoxication (n = 37), individuals diagnosed with CMI (n = 40), and “conditionally healthy” men (n = 34). Proper diagnosis confirmed by history of working contacts with a harmful industrial factor, and absence of comorbid pathologies served as inclusion criteria. Statistical processing of the results was carried out using the STATISTICA 6.0 application package (StatSoft, USA). The study has revealed a statistically significant increase in serum IL-17 concentrations, both in the patients with early signs of neurointoxication with metallic mercury vapors, and individuals with CMI, when compared with the comparison group, thus indicating its activation, and being consistent with results of several workers who showed an IL-17 increase in immunoinflammatory diseases. Correlation analysis has shown an association between IL-17 and inflammatory mediators, i.e., the patients with early signs of neurointoxication had an increased production of IL-17 accompanied by an increase in anti-inflammatory IL-10, whereas the CMI patients with an increase in IL-17 concentration showed a decrease in pro-inflammatory TNFα, thus confirming its role in immunopathogenesis of mercury neurointoxication. Further study of IL-17 involvement in the initiation and maintenance of chronic inflammation will not only contribute to better understanding of the disease origin, but also, most importantly, implication of novel, more effective treatments.

Penyakit Parkinson Akibat Merkuri pada Pekerja Penambangan Emas Skala Kecil

Introduction: Parkinson's disease is one of the fastest-growing diseases in terms of prevalence, disability, and mortality. Exposure to environmental toxic substances, such as mercury (Hg) can increase the risk of neuronal damage and neurodegenerative diseases. Purpose: The purpose of writing this article is to determine the impact of mercury exposure on the incidence of Parkinson's disease in small-scale gold mining workers. Methods: The author searches for material through the Google Scholars, NCBI, and ScienceDirect search pages by limiting the journals published in 2015-2020. In this review, the authors conducted a study of 33 scientific articles. Results: The small-scale gold mining industry is the largest source of mercury emissions in the world. Mercury gas has a negative impact on the lungs, kidneys, liver, and nervous system. Gold miners have a very high likelihood of being exposed to metallic mercury and suffering occupational mercury intoxication. Discussion: Mercury is known to be a neurotoxin that can cause neuron death and damage to the substantia nigra and other basal ganglia nuclei. Acute mercury exposure can cause tremors, memory loss, respiratory distress, and even death. Gold miners are a group that is exposed to a lot of mercury and suffers from work-induced mercury intoxication. Conclusion: Mercury-induced parkinsonism can be identified because of its predilection for accumulation and palladium and striatum damage such as damage to the substantia nigra pars in Parkinson's disease.