Neurobehavioral performance of patients diagnosed with manganism and idiopathic Parkinson disease

Child and Adolescent Manganese Biomarkers and Adolescent Postural Balance in Marietta CARES Cohort Participants

BACKGROUND

Manganese (Mn) plays a significant role in both human health and global industries. Epidemiological studies of exposed populations demonstrate a dose-dependent association between Mn and neuromotor effects ranging from subclinical effects to a clinically defined syndrome. However, little is known about the relationship between early life Mn biomarkers and adolescent postural balance.

OBJECTIVES

This study investigated the associations between childhood and adolescent Mn biomarkers and adolescent postural balance in participants from the longitudinal Marietta Communities Actively Researching Exposures Study (CARES) cohort.

METHODS

Participants were recruited into CARES when they were 7-9 y old, and reenrolled at 13-18 years of age. At both time points, participants provided samples of blood, hair, and toenails that were analyzed for blood Mn and lead (Pb), serum cotinine, hair Mn, and toenail Mn. In adolescence, participants completed a postural balance assessment. Greater sway indicates postural instability (harmful effect), whereas lesser sway indicates postural stability (beneficial effect). Multivariable linear regression models were conducted to investigate the associations between childhood and adolescent Mn biomarkers and adolescent postural balance adjusted for age, sex, height-weight ratio, parent/caregiver intelligence quotient, socioeconomic status, blood Pb, and serum cotinine.

RESULTS

CARES participants who completed the adolescent postural balance assessment (n = 123 ) were 98% White and 54% female and had a mean age of 16 y (range: 13-18 y). In both childhood and adolescence, higher Mn biomarker concentrations were significantly associated with greater adolescent sway measures. Supplemental analyses revealed sex-specific associations; higher childhood Mn biomarker concentrations were significantly associated with greater sway in females compared with males.

DISCUSSION

This study found childhood and adolescent Mn biomarkers were associated with subclinical neuromotor effects in adolescence. This study demonstrates postural balance as a sensitive measure to assess the association between Mn biomarkers and neuromotor function. https://doi.org/10.1289/EHP13381.

Effects of combined exposure of manganese and iron on serum inflammatory factor levels among workers

OBJECTIVE

The aim of the study is to examine the association between long-term occupational exposure to Mn and Fe and their health effects in workers.

METHODS

108 Mn workers were selected for the Mn exposure groups; 92 non-Mn workers were in the control group. Inductively coupled plasma-mass spectrometry was used to determine the Mn and Fe concentration in the working environment. Graphite furnace-atomic absorption spectroscopy was used to determine the blood Mn concentration of workers. Serum inflammatory factors were measured by enzyme-linked immunosorbent assay.

RESULTS

The blood Mn concentration, positive rate of clinical symptoms and serum inflammatory response in the Mn exposure group was higher than in the control group.

CONCLUSIONS

Low levels of Mn exposure may increase blood Mn concentrations, the rate of complaints of neurological symptoms and promote increased serum inflammatory response in workers.

A detailed survey of agroecological status of Allium ursinum across the republic of Serbia: Mineral composition and bioaccumulation potential

The purpose of this study was to determine the content of twenty-two biogenic elements (BEs) and potentially toxic elements (PTEs) in the soil and fresh Allium ursinum leaves from 43 different locations, in order to examine their bioaccumulation potential. Analyses of soil and plant material were carried out by using Inductively Coupled Plasma coupled with Optical Emission Spectroscopy (ICP-OES), a mercury analyzer (Hg), liquid chromatography (Cr), and AAS hybrid technique (As). The obtained results of the investigated elements were compared with the proposed limit values. The soil contamination factor (CF) as well as plant bioaccumulation factor (BAF) were calculated and the correlation analysis was performed. The results showed that the content of some BEs/PTEs in the soil were above the limit values, with two locations highly contaminated (CF > 6) with five (Cr(VI), Cu, Mn, Ni, V) and four (As, Co, Pb, V) elements. The content of As, Cd, Cr, and Pb in the leaves was higher than the permitted levels at some locations. The BAF was high (K, Ca, Zn, As), medium (Mg, Cu, B, Ni, Na, Pb), and low (Fe, Mn, Cr). The correlation between BEs/PTEs content in the leaves and soil was not significant, except for the following elements: Cd (0.37), Ca (0.34), As (0.36), Pb (0.30), and Na (0.25). The observed medium correlation suggested that the detected elements originated both from the atmosphere and the soil. Although A. ursinum at examined locations seemed to be mostly safe for consumption, a selective mechanism of adoption of certain BEs/PTEs requires continuous monitoring of their content in the future, to avoid quantities that can jeopardize human health through its consumption.

An Insight into the Molecular Mechanism of Mitochondrial Toxicant-induced Neuronal Apoptosis in Parkinson's Disease

Parkinson's disease (PD) is one of the most common progressive neurodegenerative disorders affecting approximately 1% of the world's population at the age of 50 and above. Majority of PD cases are sporadic and show symptoms after the age of 60 and above. At that time, most of the dopaminergic neurons in the region of substantia nigra pars compacta have been degenerated. Although in past decades, discoveries of genetic mutations linked to PD have significantly impacted our current understanding of the pathogenesis of this devastating disorder, it is likely that the environment also plays a critical role in the etiology of sporadic PD. Recent epidemiological and experimental studies indicate that exposure to environmental agents, including a number of agricultural and industrial chemicals, may contribute to the pathogenesis of several neurodegenerative disorders, including PD. Furthermore, there is a strong correlation between mitochondrial dysfunction and several forms of neurodegenerative disorders, including Alzheimer's disease (AD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS) and PD. Interestingly, substantia nigra of patients with PD has been shown to have a mild deficiency in mitochondrial respiratory electron transport chain NADH dehydrogenase (Complex I) activity. This review discusses the role of mitochondrial toxicants in the selective degeneration of dopaminergic neurons targeting the electron transport system that leads to Parkinsonism.

Biomarkers for occupational manganese exposure

Long-term inhalation exposure to manganese (Mn) metal or its inorganic compounds can result in manganism or subclinical neurofunctional deficits. Studies have described affected workers in Mn dioxide mining, Mn-containing ore crushing and milling facilities, manufacturing of dry-cell batteries, Mn steel and alloy production plants, and in welders. The objective of this study was to critically review existing evidence on the reliability of potential biomarkers of Mn exposure, specifically the relationship between inhalation exposure to Mn particulates in different occupational settings and Mn concentrations in blood and other biological fluids and tissues, with a particular focus on whole blood as a potentially useful medium for measuring internal tissue dose. We also examined available evidence on the relationship between Mn levels in blood and adverse clinical and subclinical neurotoxic outcomes. Three bibliographic databases were searched for relevant studies and identified references were screened by two independent reviewers. Of the 6338 unique references identified, 76 articles were retained for data abstraction. Findings indicate that the relationships between Mn in blood and both external Mn exposure indices and neurofunctional impairments are limited and inconsistent. Different sources of exposure to Mn compounds, heterogeneity in the methodological approaches, and inadequate reporting of essential information limited direct comparison of the reported findings. Among the Mn-exposure biomarkers considered in this review - including biomarkers in blood, plasma, serum, erythrocytes, urine, bone, toenails, fingernails, hair, saliva - biomarkers in whole blood may provide to be most useful in Mn biomonitoring and risk assessment.

Evaluating the neuroprotective activities of vinpocetine, punicalagin, niacin and vitamin E against behavioural and motor disabilities of manganese-induced Parkinson's disease in Sprague Dawley rats

The current study investigated the neuroprotective activity of some drugs and nutriceuticals with antioxidant and anti-inflammatory potential on the pathogenesis of Parkinson's disease (PD). Rats were categorized into seven groups: Rats received tween80 daily for 5 weeks as a control group, MnCl₂ (10 mg/kg, i.p) either alone (group II) or in combination with vinpocetine (VIN) (20 mg/kg) (group III), punicalagin (PUN) (30 mg/kg) (group IV), niacin (85 mg/kg) (group V), vitamin E (Vit E) (100 mg/kg) (group VI) or their combination (group VII). Motor activities was examined using open-field and catalepsy. Striatal monamines, acetylcholinesterase, excitatory/inhibitory neurotransmitters, redox status, pro-oxidant content, brain inflammatory, apoptotic and antioxidant biomarkers levels were assessed. Besides, histopathological investigations of different brain regions were determined. Groups (IV -GVII) showed improved motor functions of PD rats. Applied drugs significantly increased the brain levels of monoamines with the strongest effect to PUN. Meanwhile, they significantly decreased levels of acetylcholinesterase with a strongest effect to PUN. Moreover, they exhibited significant neuronal protection and anti-inflammatory abilities through significant reduction of the brain levels of COX2, TNF-α and Il-1β with a strongest effect to the PUN. Interestingly; groups (IV - GVII) showed restored glutamate/GABA balance and exhibited a pronounced decrease in caspase-3 content and GSK-3β protein expression levels. In addition, they significantly increased Bcl2 mRNA expression levels with a strongest effect for PUN. All these findings were further confirmed by the histopathological examinations. As a conclusion, we propose VIN and PUN to mitigate the progression of PD via their antioxidant, anti-inflammatory, anti-apoptotic, neurotrophic and neurogenic activities.

Environmental factors in Parkinson's disease: New insights into the molecular mechanisms

Parkinson's disease is a chronic, progressive neurodegenerative disorder affecting 2-3% of the population ≥65 years. It has long been characterized by motor impairment, autonomic dysfunction, and psychological and cognitive changes. The pathological hallmarks are intracellular inclusions containing α-synuclein aggregates and the loss of dopaminergic neurons in the substantia nigra. Parkinson's disease is thought to be caused by a combination of various pathogenic factors, including genetic factors, environmental factors, and lifestyles. Although much research has focused on the genetic causes of PD, environmental risk factors also play a crucial role in the development of the disease. Here, we summarize the environmental risk factors that may increase the occurrence of PD, as well as the underlying molecular mechanisms.

Manganese in the Diet: Bioaccessibility, Adequate Intake, and Neurotoxicological Effects

Manganese (Mn) is an essential element that participates in several biological processes. Mn serves as a cofactor for several enzymes, such as glutamine synthetase and oxidoreductases, that have an important role in the defense of the organisms against oxidative stress. The diet is the main source of Mn intake for humans, and adequate daily intake levels for this metal change with age. Moreover, in higher amounts, Mn may be toxic, mainly to the brain. Here, we provide an overview of Mn occurrence in food, addressing its bioaccessibility and discussing the dietary standard and recommended intake of Mn consumption. In addition, we review some mechanisms underlying Mn-induced neurotoxicity.

Effects of Excess Manganese on the Oxidative Status, and the Expression of Inflammatory Factors and Heat Shock Proteins in Cock Kidneys

Manganese (Mn) can have adverse effects on organisms as a result of heavy or chronic exposure, including neurological damage. This study examined the effects of chronic exposure to manganese chloride (MnCl₂) on various biochemical indices of inflammatory cytokines, antioxidant enzymes, and heat shock proteins (HSPs) in the kidneys of Hy-line cocks. The exposures were carried out using 600, 900, or 1800 mg/kg doses of MnCl₂ administered for periods of 30, 60, and 90 days. The exposure experiments indicated that Mn concentration in the kidneys increased over time and that Mn exposure potentially caused ultrastructural changes to the cells. Treatment with Mn was seen to increase the levels of various biomarkers, including protein carbonyl group content; DNA-protein cross-links (DPCs) and the mRNA expression of inflammatory factors such as tumor necrosis factor-α (TNF-α), nuclear factor-κB p50 (NF-κB p50), cyclooxygenase-2 (COX-2), and prostaglandin E synthase (PGES). The levels of other biomarkers were found to decrease as a result of Mn exposure, including the mRNA expression of oxidation indexes such as copper-zinc superoxide dismutase (CuZn-SOD), manganese superoxide dismutase (Mn-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT). Accompanying the above changes, Mn exposure was seen to result in the relative mRNA and protein expression of HSPs 90, 70, 60, 40, and 27 increasing significantly. Thus, in cock kidneys, HSPs attenuated the biological changes caused by toxic exposure to Mn. This mechanism needs further exploration.