PCBs, polychlorinated biphenyls, have been linked to autism, based on results of emerging research from the University of California-Davis and Washington State University.
The research suggests that PCB exposure may increase risks for autism in some children, said PsychCentral. Dr. Pamela Lein, a developmental neurobiologist and professor of molecular biosciences in the UC Davis School of Veterinary Medicine, explained that the toxic chemicals can lead to a disruption of brain nerve connections in children. “Impaired neuronal connectivity is a common feature of a number of conditions, including autism spectrum disorders,” Dr. Lein told PsychCentral.
As we’ve long explained, PCBs include some 200 compounds and are a class of very toxic chemicals ubiquitously found in construction materials and electrical products in many buildings built from the 1950s until 1978, when they were phased out. PCBs have been linked to skin irritations, some cancers, and a variety of adverse health effects to the immune, reproductive, nervous, and endocrine systems. PCBs accumulate in the environment, presenting serious health issues, and can remain in our bodies for many years. The longer we live, the more these toxins build in our systems, increasing in strength over time.
The researchers say that PCBs likely serve as an environmental trigger for autism in genetically susceptible children, said PsychCentral, noting that two related studies, published in the journal Environmental Health Perspectives, also presented data strengthening the belief that the developing brain is vulnerable to environmental exposures and show how PCBs could increase autism risks. “We don’t think PCB exposure causes autism,” Dr. Lein said, “but it may increase the likelihood of autism in children whose genetic makeup already compromises the processes by which neurons form connections,” she added, wrote PsychCentral.
Gary Wayman, Ph.D., of Washington State University’s Program in Neuroscience, described the molecular pathway controlling the brain’s calcium signaling, which guides normal dendrite growth. He also discovered that some important cells are activated with increased calcium levels, said PsychCentral. “The wiring of billions of neurons is dependent on the health of this cellular process and is crucial to proper development of virtually all complex behaviors, learning, memories and language,” said Wayman.
The team focused on the neurons of the hippocampus, the brain region linked to learning and memory and which is known to suffer weakened connectivity in a number of neurodevelopmental disorders, and looked at the effect of non-dioxin-like PCBs, linked to increased calcium levels in neurons, said PsychCentral. “The new findings provide good evidence that PCBs could add to autism risk in genetically predisposed children,” said researchers. “Understanding the fundamental mechanisms by which PCBs alter neural networks sets the stage for research on environmental contaminants that are structurally related to PCBs,” they added, said PsychCentral.
We recently wrote that autism was potentially linked to parental exposure to solvents, including lacquer, varnish, and xylene. The research revealed that solvent exposure was greater in parents whose children were diagnosed with an Autism Spectrum Disorder (ASD), versus parents of unaffected children. Parents of children with ASDs, were also likelier to report exposure to asphalt and solvents, versus parents of unaffected children.
We’ve long explained that reports of ASDs are on the rise, in part because of better diagnostic tools, but many have long believed the increase could be due to environmental exposures. The origins of autism have long been questioned and critics have blamed PCBs; mercury; vaccinations; some antidepressant medications; pesticides; pollution; high-fructose corn syrup (HFCS), which was found, in two studies, to contain mercury. ASDs include not only autism, but also Asperger’s syndrome and pervasive developmental disorder, not otherwise specified, and involve issues with social interaction, verbal and nonverbal communication, and repetitive behaviors.