Amyotrophic Lateral Sclerosis After Exposure to Manganese from Traditional Medicine Procedures in Kenya

Blood lead concentrations in exposed forecourt attendants and taxi drivers in parts of South Africa

BACKGROUND

Leaded fuel was banned in South Africa in 2006, in order to improve human health and reduce environmental pollution. Lead (Pb) has been suggested to contribute to the development of neurodegenerative disorders, and the role of respiratory exposure to Pb from petrol fumes should not be neglected in this context. In addition to Pb, petrol contains various harmful chemicals including other neurotoxic metals and hydrocarbons.

OBJECTIVES AND METHODS

Here, we investigated concentrations of Pb and other metals in blood from petrol station forecourt attendants (n = 38), taxi drivers (n = 21), and unexposed controls (n = 36). Taxi drivers and forecourt attendants were divided into three groups each, based on number of years worked. A questionnaire was designed to investigate the health status of the participants. Blood samples were collected by medical professionals and analyzed for metal concentrations by ICP-MS.

RESULTS

A positive correlation between number of years worked and Pb blood concentrations was found. The highest Pb concentration (60.2 µg/L) was observed in a forecourt attendant who had worked 11-20 years, and the average Pb concentration in this group (24.5 µg/L) was significantly (p < 0.05) higher than in forecourt attendants who had worked 2-5 years (10.4 µg/L). Some individuals had elevated concentrations of manganese, arsenic, cadmium, chromium and cobalt, yet not significantly elevated at the group level. The blood levels of arsenic appeared to be related to smoking. Mood swings, dizziness, headaches and tiredness were reported by the workers.

CONCLUSION

Blood Pb concentrations in petrol station forecourt attendants and taxi drivers exposed to leaded petrol are elevated and correlate to exposure time. A health monitoring program should be erected for all individuals working in these industries, and preventive measures should be implemented to eliminate metal exposure from petrol.

ALS in Africa: current knowledge and exciting opportunities for future study - short communication

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that can present with motor and extra-motor manifestations. Its global prevalence is 4.42 per 1 000 000, and it has a high mortality rate. In sub-Saharan Africa alone, 15 per 100 000 develop ALS mainly between their 40s and 60s and only one-fourth of them have access to treatment. ALS was found to be not only affected by genetic variation but also by the patient's mood and lifestyle. In Africa, males and younger people tend to be affected with ALS and rarely present with bulbar onset. ALS diagnosis is very challenging due to the lack of ALS-specific biomarkers and the sharing of some clinical features with other syndromes. ALS treatment is mainly riluzole and supportive treatment via nasogastric tube and ventilatory support. The access to treatment in Africa is very limited, thus a very bad prognosis with a median survival time of 14 months post-diagnosis. Further research is needed to assess the real situation in Africa and to try to closely monitor patients suffering from ALS.

Restoration of metal homeostasis: a potential strategy against neurodegenerative diseases

Metal homeostasis is critical to normal neurophysiological activity. Metal ions are involved in the development, metabolism, redox and neurotransmitter transmission of the central nervous system (CNS). Thus, disturbance of homeostasis (such as metal deficiency or excess) can result in serious consequences, including neurooxidative stress, excitotoxicity, neuroinflammation, and nerve cell death. The uptake, transport and metabolism of metal ions are highly regulated by ion channels. There is growing evidence that metal ion disorders and/or the dysfunction of ion channels contribute to the progression of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS). Therefore, metal homeostasis-related signaling pathways are emerging as promising therapeutic targets for diverse neurological diseases. This review summarizes recent advances in the studies regarding the physiological and pathophysiological functions of metal ions and their channels, as well as their role in neurodegenerative diseases. In addition, currently available metal ion modulators and in vivo quantitative metal ion imaging methods are also discussed. Current work provides certain recommendations based on literatures and in-depth reflections to improve neurodegenerative diseases. Future studies should turn to crosstalk and interactions between different metal ions and their channels. Concomitant pharmacological interventions for two or more metal signaling pathways may offer clinical advantages in treating the neurodegenerative diseases.

Oxidative Stress in Amyotrophic Lateral Sclerosis: Synergy of Genetic and Environmental Factors

Amyotrophic lateral sclerosis (ALS) is a grievous neurodegenerative disease whose survival is limited to only a few years. In spite of intensive research to discover the underlying mechanisms, the results are fairly inconclusive. Multiple hypotheses have been regarded, including genetic, molecular, and cellular processes. Notably, oxidative stress has been demonstrated to play a crucial role in ALS pathogenesis. In addition to already recognized and exhaustively studied genetic mutations involved in oxidative stress production, exposure to various environmental factors (e.g., electromagnetic fields, solvents, pesticides, heavy metals) has been suggested to enhance oxidative damage. This review aims to describe the main processes influenced by the most frequent genetic mutations and environmental factors concurring in oxidative stress occurrence in ALS and the potential therapeutic molecules capable of diminishing the ALS related pro-oxidative status.

A perspective on persistent toxicants in veterans and amyotrophic lateral sclerosis: identifying exposures determining higher ALS risk

Multiple studies indicate that United States veterans have an increased risk of developing amyotrophic lateral sclerosis (ALS) compared to civilians. However, the responsible etiological factors are unknown. In the general population, specific occupational (e.g. truck drivers, airline pilots) and environmental exposures (e.g. metals, pesticides) are associated with an increased ALS risk. As such, the increased prevalence of ALS in veterans strongly suggests that there are exposures experienced by military personnel that are disproportionate to civilians. During service, veterans may encounter numerous neurotoxic exposures (e.g. burn pits, engine exhaust, firing ranges). So far, however, there is a paucity of studies investigating environmental factors contributing to ALS in veterans and even fewer assessing their exposure using biomarkers. Herein, we discuss ALS pathogenesis in relation to a series of persistent neurotoxicants (often emitted as mixtures) including: chemical elements, nanoparticles and lipophilic toxicants such as dioxins, polycyclic aromatic hydrocarbons and polychlorinated biphenyls. We propose these toxicants should be directly measured in veteran central nervous system tissue, where they may have accumulated for decades. Specific toxicants (or mixtures thereof) may accelerate ALS development following a multistep hypothesis or act synergistically with other service-linked exposures (e.g. head trauma/concussions). Such possibilities could explain the lower age of onset observed in veterans compared to civilians. Identifying high-risk exposures within vulnerable populations is key to understanding ALS etiopathogenesis and is urgently needed to act upon modifiable risk factors for military personnel who deserve enhanced protection during their years of service, not only for their short-term, but also long-term health.

Determination of 18 Trace Elements in 10 Batches of the Tibetan Medicine Qishiwei Zhenzhu Pills by Direct Inductively Coupled Plasma-Mass Spectrometry

Qishiwei Zhenzhu pills (QSW) was first recorded in the Tibetan medicine classic Si Bu Yi Dian and has been used to treat "Baimai" disease, stroke, paralysis, hemiplegia, cerebral hemorrhage, and other diseases till today. This prescription contains more than 70 medicines including myrobalan, pearl, agate, opal, bezoar, coral, musk, gold, silver, and a mineral mixture Zuotai. As a result, QSW contains a large amount of mercury, copper, lead, and other trace elements. The aim of this study was to determine the 18 trace elements (lithium, beryllium, scandium, vanadium, chromium, manganese, cobalt, nickel, copper, arsenic, strontium, argentum, cadmium, cesium, barium, lead, aurum, and mercury) in 10 batches of QSW produced by 5 pharmaceutical companies (Ganlu Tibetan Medicine Co., Ltd. has 6 different batches) by direct inductively coupled plasma-mass spectrometry (ICP-MS). ICP-MS is a rapid, sensitive, accurate methodology allowing the determination of 18 elements simultaneously. The results showed that each element had an excellent linear relationship in the corresponding mass concentration range. The results showed that the rank order of the elements in QSW was copper > mercury > lead from high to low, with the mass fraction higher than 6000 μg/kg; the mass fractions of argentum, arsenic, manganese, aurum, strontium, barium, chromium, and nickel were in the range of 33-1034 μg/kg; and the mass fractions of vanadium, cobalt, lithium, beryllium, cadmium, scandium, and cesium were lower than 10 μg/kg. The reproducibility from the same manufacturer (Tibet Ganlu Tibetan Medicine Co., Ltd.) was relatively high; however, the element amounts among 5 manufacturers were different, which could affect the efficacy and toxicity of QSW. All in all, ICP-MS can be used as an effective tool for the analysis of trace elements in QSW and standard quality control needs to be enforced across different manufactures.

Metals in ALS TDP-43 Pathology

Amyotrophic lateral sclerosis (ALS), Alzheimer's disease, Parkinson's disease and similar neurodegenerative disorders take their toll on patients, caregivers and society. A common denominator for these disorders is the accumulation of aggregated proteins in nerve cells, yet the triggers for these aggregation processes are currently unknown. In ALS, protein aggregation has been described for the SOD1, C9orf72, FUS and TDP-43 proteins. The latter is a nuclear protein normally binding to both DNA and RNA, contributing to gene expression and mRNA life cycle regulation. TDP-43 seems to have a specific role in ALS pathogenesis, and ubiquitinated and hyperphosphorylated cytoplasmic inclusions of aggregated TDP-43 are present in nerve cells in almost all sporadic ALS cases. ALS pathology appears to include metal imbalances, and environmental metal exposure is a known risk factor in ALS. However, studies on metal-to-TDP-43 interactions are scarce, even though this protein seems to have the capacity to bind to metals. This review discusses the possible role of metals in TDP-43 aggregation, with respect to ALS pathology.