Neurotoxicity
Trends in neurodevelopmental disability burden due to early life chemical exposure in the USA from 2001 to 2016: A population-based disease burden and cost analysis
SYNOPSIS
PBDE (chemicals from Flame Retardants) exposure was the greatest contributor to intellectual disability burden, resulting in a total of 162 million IQ points lost and over 738,000 cases of intellectual disability.
CITATION
Abigail Gaylord, Gwendolyn Osborne, Akhgar Ghassabian, Julia Malits, Teresa Attina, Leonardo Transande; Molecular and Cellular Endocrinology; Online: 14 January 2020. doi 10.1016/j.mce.2019.110666.
SUMMARY
Endocrine disrupting chemicals are known to cause neurodevelopmental toxicity through direct and indirect pathways. In this study we used data from the National Health and Nutrition Examination Surveys, along with known exposure-disease relationships, to quantify the intellectual disability burden attributable to in utero exposure to polybrominated diphenyl ethers (PBDEs commonly known as Flame Retardants), organophosphates, and methylmercury and early life exposure to lead. We also estimated the cost of the IQ points lost and cases of intellectual disability. PBDE exposure was the greatest contributor to intellectual disability burden, resulting in a total of 162 million IQ points lost and over 738,000 cases of intellectual disability. This was followed by lead, organophosphates, and methylmercury. From 2001 to 2016, IQ loss from PBDEs, methylmercury, and lead have decreased or remained stagnant. Organophosphate exposure measurements were only available up to 2008 but did show an increase in organophosphate-attributable IQ loss. Although most of these trends show benefit for children’s neurodevelopmental health, they may also point towards the use of potentially harmful substitutions for chemicals that are being phased out.
Association between maternal fluoride exposure during pregnancy and IQ scores in offspring in Canada
SYNOPSIS
Lower IQ in children is strongly associated with higher levels of maternal fluoride exposure during pregnancy.
CITATION
SUMMARY
In this Canadian study, maternal exposure to higher levels of fluoride during pregnancy was strongly associated with lower IQ in children. In addition, the study found that women living in areas with fluoridated tap water had significantly higher average concentrations of fluoride in their urine compared to women without fluoridated tap water. Fluoridated cities in Canada use the same fluoride concentration (0.7 milligrams per liter) as the U.S. has used since 2015—a concentration recommended by the CDC as “optimal.” The authors raise concerns about the safety of maternal exposure to “optimally fluoridated water” and note that, at the population level, their results translate to “millions of IQ levels lost.”
Rethinking mercury: the role of selenium in the pathophysiology of mercury toxicity
SYNOPSIS
Mercury in the body produces a selenium deficiency state that increases toxicity.
CITATION
Spiller HA. Rethinking mercury: the role of selenium in the pathophysiology of mercury toxicity. Clinical Toxicology. 2018;56(5):313-326.
SUMMARY
This study makes the case that mercury’s multifaceted interactions with selenium are a central feature of mercury toxicity. The authors argue that “the previously suggested ‘protective effect’ of selenium against mercury toxicity may in fact be backwards”—because of mercury’s affinity for selenium, mercury can actually produce a selenium deficiency state that promotes oxidative stress and inhibits the body’s regenerative mechanisms. Depending on the form of mercury and other factors, selenium supplementation may have some benefits for restoring adequate selenium status and mitigating the toxicity of mercury, but it does not appear to promote increased elimination of mercury.
Neuroprotective effect of Allium cepa L. in aluminium chloride induced neurotoxicity
SYNOPSIS
Supplementation with Allium cepa L. significantly improved muscle coordination and memory deficit and decreased abnormal aluminium deposition in the brains of exposed animals.
CITATION
Tanveer Singh and Rajesh Kumar Goel. NeuroToxicology, 49 (2015) 1–7.
SUMMARY
Chronic aluminium administration resulted in significant motor incoordination and memory deficits, which were also endorsed biochemically as there was increased oxidative stress as well as elevated aluminium levels in the brain. Supplementation with A. cepa in aluminium exposed animals significantly improved muscle coordination and memory deficits as well as reduced oxidative stress and decreased abnormal aluminium deposition in the brain.
Transcriptomic analyses of neurotoxic effects in mouse brain after intermittent neonatal administration of thimerosal
SYNOPSIS
Chinese scientists find mice injected with thimerosal (vaccine mercury) have behavioral impairments similar to autism.
CITATION
Li X, Qu F, Xie W, et al. Toxicological Sciences. 2014;139:452–465.
SUMMARY
“Thimerosal-treated mice exhibited neural development delay, social interaction deficiency, and inclination of depression. Apparent neuropathological changes were also observed in adult mice neonatally treated with thimerosal. High-throughput RNA sequencing of autistic-behaved mice brains revealed the alternation of a number of canonical pathways involving neuronal development, neuronal synaptic function, and the dysregulation of endocrine system.”
Mechanisms of aluminum adjuvant toxicity and autoimmunity in pediatric populations
SYNOPSIS
Canadian researchers review literature on autoimmunity and neurological risks from vaccine adjuvant aluminum, express doubts regarding safety testing.
CITATION
L Tomljenovic, CA Shaw. Lupus. 2012;21:223–230.
SUMMARY
“Immune challenges during early development, including those vaccine-induced, can lead to permanent detrimental alterations of the brain and immune function. Experimental evidence also shows that simultaneous administration of as little as two to three immune adjuvants can overcome genetic resistance to autoimmunity. In spite of the widespread agreement that vaccines are largely safe and serious adverse complications are extremely rare, a close scrutiny of the scientific literature does not support this view. For example, to date, the clinical trials that could adequately address vaccine safety issues have not been conducted (i.e., comparing health outcomes in vaccinated versus non-vaccinated children). Infants and young children should not be viewed as ‘small adults.’ Their unique physiology makes them much more vulnerable to noxious environmental insults in comparison with the adult population. In spite of this, children are routinely exposed to much higher levels of Al vaccine adjuvants than adults, even though adequate safety data on these compounds are lacking. That Al vaccine adjuvants can induce significant autoimmune conditions in humans can hardly be disputed, although still debatable is how common such side effects are. However, the existing data (or lack thereof) raise questions on whether the current vaccines aimed at pediatric populations can be accepted as having adequate safety profiles. Because infants and children represent those who may be most at risk for complications following vaccination, a more rigorous evaluation of potential vaccine-related adverse health impacts in pediatric populations than what has been provided to date is urgently needed.”
Influence of pediatric vaccines on amygdala growth and opioid ligand binding in rhesus macaque infants: A pilot study
SYNOPSIS
Baby monkeys given U.S. vaccine schedule had brain abnormalities in region responsible for social and emotional development.
CITATION
Laura Hewitson, Brian J. Lopresti, Carol Stott, N. Scott Mason and Jaime Tomko1. ACTA Neurobiological Experimentals, 2010 70: 147–164.
SUMMARY
“The data suggest that vaccine exposure may be associated with significant disturbances in central opioidergic pathways in this model… Volumetric analyses identified significantly greater total brain volume in exposed compared with unexposed animals at both measured time points. These results raise the possibility that multiple vaccine exposures during the previous 3-4 months may have had a significant impact on brain growth and development.”
Aluminum hydroxide injections lead to motor deficits and motor neuron degeneration
SYNOPSIS
Vaccine aluminum injected into mice created significant motor deficits and motor neuron degeneration.
CITATION
Christopher A. Shaw and Michael S. Petrik. Journal Inorganic Biochemistry, 2009 November; 103(11): 1555.
SUMMARY
“Aluminum-treated mice showed significantly increased apoptosis of motor neurons and increases in reactive astrocytes and microglial proliferation within the spinal cord and cortex. Morin stain detected the presence of aluminum in the cytoplasm of motor neurons with some neurons also testing positive for the presence of hyper-phosphorylated tau protein, a pathological hallmark of various neurological diseases, including Alzheimer’s disease and frontotemporal dementia. A second series of experiments was conducted on mice injected with six doses of aluminum hydroxide. Behavioural analyses in these mice revealed significant impairments in a number of motor functions as well as diminished spatial memory capacity. The demonstrated neurotoxicity of aluminum hydroxide and its relative ubiquity as an adjuvant suggest that greater scrutiny by the scientific community is warranted. Overall, the results reported here mirror previous work that has clearly demonstrated that aluminum, in both oral and injected forms, can be neurotoxic.”
Delayed acquisition of neonatal reflexes in newborn primates receiving a thimerosal-containing Hepatitis B vaccine: Influence of gestational age and birth weight
SYNOPSIS
Newborn monkeys given a mercury-containing hepatitis b vaccine had significant delays in neonatal reflexes and neurological development.
CITATION
Laura Hewitson, Lisa A. Houser, Carol Stott, Gene Sackett, Jaime L. Tomko, David Atwood, Lisa Blue, E. Railey White, Andrew J. Wakefield. NeuroToxicology, 2009; doi:10.1016/j.neuro.2009.09.008.
SUMMARY
“In summary, this study provides preliminary evidence of abnormal early neurodevelopmental responses in male infant rhesus macaques receiving a single dose of Th-containing HB vaccine at birth and indicates that further investigation is merited.”
Thimerosal Neurotoxicity is Associated with Glutathione Depletion: Protection with Glutathione Precursors
SYNOPSIS
Vaccine mercury depletes a vital antioxidant, glutathione.
CITATION
S.J. James, William Slikker, Stepan Melnyk, Elizabeth New,
Marta Pogribna, Stefanie Jernigan. NeuroToxicology, 26 (2005) 1–8.
SUMMARY
“Thimerosal is an antiseptic containing 49.5% ethyl mercury that has been used for years as a preservative in many infant vaccines and in flu vaccines. Environmental methyl mercury has been shown to be highly neurotoxic, especially to the developing brain. Because mercury has a high affinity for thiol (sulfhydryl (-SH)) groups, the thiol-containing antioxidant, glutathione (GSH), provides the major intracellular defense against mercury-induced neurotoxicity. Cultured neuroblastoma cells were found to have lower levels of GSH and increased sensitivity to thimerosal toxicity compared to glioblastoma cells that have higher basal levels of intracellular GSH. Thimerosal-induced cytotoxicity was associated with depletion of intracellular GSH in both cell lines. Although Thimerosal has been recently removed from most children’s vaccines, it is still present in flu vaccines given to pregnant women, the elderly, and to children in developing countries.”