Immune

Excerpt:
“The literature strongly supports that autism is most accurately seen as an acquired cellular detoxification deficiency syndrome with heterogeneous genetic predisposition that manifests pathophysiologic consequences of accumulated, run-away cellular toxicity. At a more general level, it is a form of a toxicant-induced loss of tolerance of toxins, and of chronic and sustained ER overload (“ER hyperstress”), contributing to neuronal and glial apoptosis via the unfolded protein response (UPR). Inherited risk of impaired cellular detoxification and circulating metal re-toxification in neurons and glial cells accompanied by chronic UPR is key.”

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  • March 16, 2018

Excerpt:
“Environmental mercury is neurotoxic at doses well below the current reference levels considered to be safe, with evidence of neurotoxicity in children exposed to environmental sources including fish consumption and ethylmercury-containing vaccines. Possible neurotoxic mechanisms of mercury include direct effects on sulfhydryl groups, pericytes and cerebral endothelial cells, accumulation within astrocytes, microglial activation, induction of chronic oxidative stress, activation of immune-inflammatory pathways and impairment of mitochondrial functioning. (Epi-)genetic factors which may increase susceptibility to the toxic effects of mercury in ASD include the following: a greater propensity of males to the long-term neurotoxic effects of postnatal exposure and genetic polymorphisms in glutathione transferases and other glutathione-related genes and in selenoproteins. Furthermore, immune and inflammatory responses to immunisations with mercury-containing adjuvants are strongly influenced by polymorphisms in the human leukocyte antigen (HLA) region and by genes encoding effector proteins such as cytokines and pattern recognition receptors. Some epidemiological studies investigating a possible relationship between high environmental exposure to methylmercury and impaired neurodevelopment have reported a positive dose-dependent effect.”

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  • July 22, 2017

Abstract

Autism is a neurodevelopmental disorder characterized by deficits in communication and social skills as well as repetitive and stereotypical behaviors. While much effort has focused on the identification of genes associated with autism, research emerging within the past two decades suggests that immune dysfunction is a viable risk factor contributing to the neurodevelopmental deficits observed in autism spectrum disorders (ASD). Further, it is the heterogeneity within this disorder that has brought to light much of the current thinking regarding the subphenotypes within ASD and how the immune system is associated with these distinctions. This review will focus on the two main axes of immune involvement in ASD, namely dysfunction in the prenatal and postnatal periods. During gestation, prenatal insults including maternal infection and subsequent immunological activation may increase the risk of autism in the child. Similarly, the presence of maternally derived anti-brain autoantibodies found in ~20% of mothers whose children are at risk for developing autism has defined an additional subphenotype of ASD. The postnatal environment, on the other hand, is characterized by related but distinct profiles of immune dysregulation, inflammation, and endogenous autoantibodies that all persist within the affected individual. Further definition of the role of immune dysregulation in ASD thus necessitates a deeper understanding of the interaction between both maternal and child immune systems, and the role they have in diagnosis and treatment.

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  • September 21, 2016

Abstract

In this section, I explore the effects of mercury and inflammation on transsulfuration reactions, which can lead to elevations in androgens, and how this might relate to the male preponderance of autism spectrum disorders (ASD). It is known that mercury interferes with these biochemical reactions and that chronically elevated androgen levels also enhance the neurodevelopmental effects of excitotoxins. Both androgens and glutamate alter neuronal and glial calcium oscillations, which are known to regulate cell migration, maturation, and final brain cytoarchitectural structure. Studies have also shown high levels of DHEA and low levels of DHEA-S in ASD, which can result from both mercury toxicity and chronic inflammation. Chronic microglial activation appears to be a hallmark of ASD. Peripheral immune stimulation, mercury, and elevated levels of androgens can all stimulate microglial activation. Linked to both transsulfuration problems and chronic mercury toxicity are elevations in homocysteine levels in ASD patients. Homocysteine and especially its metabolic products are powerful excitotoxins. Intimately linked to elevations in DHEA, excitotoxicity and mercury toxicity are abnormalities in mitochondrial function. A number of studies have shown that reduced energy production by mitochondria greatly enhances excitotoxicity. Finally, I discuss the effects of chronic inflammation and elevated mercury levels on glutathione and metallothionein.

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  • January 1, 2015

Abstract

Recent studies of genomic variation associated with autism have suggested the existence of extreme heterogeneity. Large-scale transcriptomics should complement these results to identify core molecular pathways underlying autism. Here we report results from a large-scale RNA sequencing effort, utilizing region-matched autism and control brains to identify neuronal and microglial genes robustly dysregulated in autism cortical brain. Remarkably, we note that a gene expression module corresponding to M2-activation states in microglia is negatively correlated with a differentially expressed neuronal module, implicating dysregulated microglial responses in concert with altered neuronal activity-dependent genes in autism brains. These observations provide pathways and candidate genes that highlight the interplay between innate immunity and neuronal activity in the aetiology of autism.

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  • December 10, 2014

Abstract

A role for immunological involvement in autism spectrum disorder (ASD) has long been hypothesized. This review includes four sections describing (1) evidence for a relationship between familial autoimmune disorders and ASD; (2) results from post-mortem and neuroimaging studies that investigated aspects of neuroinflammation in ASD; (3) findings from animal model work in ASD involving inflammatory processes; and (4) outcomes from trials of anti-inflammatory/immune-modulating drugs in ASD that have appeared in the literature. Following each section, ideas are provided for future research, suggesting paths forward in the continuing effort to define the role of immune factors and inflammation in the pathophysiology of a subtype of ASD

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  • November 13, 2014

Abstract

The autism spectrum disorders (ASD) are a group of related neurodevelopmental disorders that have been increasing in incidence since the 1980s. Despite a considerable amount of data being collected from cases, a central mechanism has not been offered. A careful review of ASD cases discloses a number of events that adhere to an immunoexcitotoxic mechanism. This mechanism explains the link between excessive vaccination, use of aluminum and ethylmercury as vaccine adjuvants, food allergies, gut dysbiosis, and abnormal formation of the developing brain. It has now been shown that chronic microglial activation is present in autistic brains from age 5 years to age 44 years. A considerable amount of evidence, both experimental and clinical, indicates that repeated microglial activation can initiate priming of the microglia and that subsequent stimulation can produce an exaggerated microglial response that can be prolonged. It is also known that one phenotypic form of microglia activation can result in an outpouring of neurotoxic levels of the excitotoxins, glutamate and quinolinic acid. Studies have shown that careful control of brain glutamate levels is essential to brain pathway development and that excesses can result in arrest of neural migration, as well as dendritic and synaptic loss. It has also been shown that certain cytokines, such as TNF-alpha, can, via its receptor, interact with glutamate receptors to enhance the neurotoxic reaction. To describe this interaction I have coined the term immunoexcitotoxicity, which is described in this article.

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  • November 1, 2014