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Researchers from Boston University School of Medicine (Ash et al., 2019) have reported on new data demonstrating a direct mechanistic link between exposure to heavy metals and risk for developing ALS. These studies showed that lead (Pb) and methyl mercury (MeHg) disrupt the homeostasis of TDP-43 in neurons. These metals also triggered the accumulation of insoluble TDP-43 in cultured cells and in the cortices of exposed mice. These new data provide evidence for a mechanistic link between a commonly cited environmental risk factor for ALS, and molecular changes in TDP-43, the primary pathological protein accumulating in ALS.
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Manganese exposure exacerbates progressive motor deﬁcits and neurodegeneration in the Mito Park mouse model of Parkinson’s disease.
A recently study by Langley and colleagues used the MitoPark mouse model of PD which recapitulates the behavioral symptoms and neuropathological changes associated with PD to investigate the effects of low level manganese exposure on disease progression. The study found that exposure to manganese (10 mg/kg, p.o. daily for 4 weeks) accelerated the rate of progression of motor deﬁcits in MitoPark mice and also enhanced oxidative damage in the striatum and substantia nigra (SN) of these mice. These new results provide additional data in the growing body of research indicating that neurotoxicants such as manganese that increase oxidative stress can augment mitochondrial dysfunction and exacerbate nigrostriatal neurodegeneration which in turn can unmask latent PD-related behavioral symptoms.
Link to citation in Pubmed
ScienceDaily is reporting on recent research from Glen Hanson and colleagues from the University of Utah showing that Attention Deficit Hyperactivity Disorder is associated with an increased risk for parkinsonism. The study found that patient's with ADHD were more likely to develop early onset parkinsonism than individuals of the same gender and age who did not have ADHD. The risk was dramatically increased, eight- to nine-fold among those ADHD patients who had a history of being treated with amphetamine-like drugs. This study adds to the growing body of literature implicating chemicals in a younger age at onset of Parkinson's disease and other forms of parkinsonism.
Link to story in ScienceDaily
Is it possible that people could be at greater risk for toxic effects when they are exposed to chemical mixtures than when they are exposed to the same chemicals at the same concentrations individually?
According to Professor Andreas Kortenkamp, of Brunel University "An increasing body of science shows a neglect of mixture effects can cause chemical risks to be underestimated". Regulators have long operated under the assumption that if the concentration of each chemical in a mixture does not exceed the recommended exposure limits, that risk for toxicity is low. But, when chemicals share common mechanisms of action they can produce additive or synergistic effects even at exposure leaves below current regulatory limits. The logic behind additive and synergistic effects on the central nervous system is best exemplified by the consequences of drinking alcohol after ingesting benzodiazepines. Since both chemicals act to enhance inhibitory neurotransmission, their combined effect on behavior and consciousness will be greater than that which occurs the same dose of either chemical alone. Physicians and toxicologists who work in Emergency Departments are well aware of this type of interaction. So why can't those involved in creating regulatory policies for chemical constituents of paints, solvents, and pesticides create policies that anticipate these same risks? The answer may be due in part to the fact that unlike alcoholic beverage and benzodiazepines, industrial solvents and pesticides are "not intended for human consumption" and because proper industrial hygiene practices are expected to be sufficient to reduced exposure to levels below the current occupational exposure limits.
Link to original story appearing in Medicalxpress
Dr. Marcia Ratner, discusses the role neurotoxic chemical exposures play in creating neurodiverse conditions, and gives tips on prevention and treatment options.
Link to Blog Post at DifferentBrains.org
Ana Sandoiu reports in Medical News Today on her interview with Dr. Scott Ryan whose research is focused on investigating why some people develop Parkinson's disease while other do not," According to Dr. Ryan, "People with a predisposition for Parkinson's disease are more affected by these low-level exposures to agrochemicals and therefore more likely to develop the disease."
He and his colleagues used human cells to study the role of two pesticides, paraquat and maneb, in Parkinson's disease. They found that the levels of these toxic chemicals that impaired the cells in their model were below those deemed safe by the United States Environmental Protection Agency (EPA) suggesting that the EPA's guidelines for paraquat and maneb should be re-evaluated.
Link to original story in Medical News Today
ABC News is reporting on new research from Kristine Yaffe, MD, of the University of California, San Francisco, show that head injuries leading to a mild concussion or mild traumatic brain injury are associated with an increased risk of developing Parkinson's disease. This new data expands on that from previous research which has found between that moderate to severe traumatic brain injury are associated with an increased risk of developing Parkinson's disease.
We have always included questions about a patients history of head injury and loss of consciousness in our questionnaires designed to assess for associations between exposure to chemicals and age at onset of neurodegernative diseases such as Parkinson's. We believe that head injuries like chemical exposures can modify the subclinical course of neurodegenerative diseases to thereby alter age at onset of overt symptoms and therefore, must be considered in the differential diagnosis.
Link to story at ABC News
Documenting VOCs in the workplace just got easier with introduction of game changing smartphone technology
The DailyMail is reporting on the release of a new smartphone from CAT that has an on-board air sensor made by the Sensirion. The new phone can detect Volatile Organic Compounds (VOCs) commonly found in paints, solvents, carpets, furniture and cleaning products. This phone is a potential game changer for anyone at risk of occupational or environmental exposures to VOCs. The data these phones can detect could potentially be used in future research aimed at understanding the role of neurotoxic VOCs in age-related neurodegenerative diseases as well.
Link to original story in DailyMail
Link to CAT website
The WKU Herald is reporting a story about ethnobotanist Paul Alan Cox whose research looking at the Ogimi people of rural Japan, suggests that a diet high in the amino acid L-serine may provide neuroprotection and even delay Alzheimer’s disease onset until very late in life. According to Cox “If we dose early, we can push off Alzheimer’s until you’re 115 to 120 years old,” According to the article, the "standard Ogimi diet consists of various types of seaweed, tofu and pork, and is the highest diet ever measured in L-serine". So should you load up on L-serine? Not so fast, but you may want to follow the clinical trials that are underway at Dartmouth-Hitchcock Medical Center.
Link to original story on WKU Herald website.
Link to FDA website for clinical Trial
An association between cadmium exposure and cognitive deficits in mice has been reported by Wang an colleagues. Exposure to cadmium was associated with impaired performance on hippocampus-dependent learning and memory tasks. An association between urinary cadmium levels and AD risk in human subjects has previously been reported by Peng and colleagues. Peng and colleagues suggested that toxicological studies were need to further elucidate their findings in humans. This new study in mice lends support to the hypothesis that there could be an interaction between these two factors shown to influence cognitive performance.
Link to Peng et al, 2017
Link to Wang et al, 2018
Dr. Marcia Ratner shares and reviews the news.