ARCHIVED HEALTH FACT
Vaccines Not Linked To Autism, ADHD
This news story is an example of how very complex basic research can be given
a simple "spin" to try and make it more interesting to the general
public. A Health Day item headlined "Toxins Linked to Autism, ADHD" was
based on a press release from Northeastern University captioned "New
Research Suggests Link Between Vaccine Ingredients and Autism, ADHD."
The original scientific report (to be published in the
next issue of Molecular Psychiatry) was actually entitled "Activation of methionine
synthase by insulin-like growth factor-1 and dopamine: a target for
neurodevelopmental toxins and thimerosal." This research was done in a cell
line derived from a human neuroblastoma. In these cells
cultured in the laboratory, insulin-like growth factor-1 and dopamine activated
a specific enzyme and this activation could be blocked by several neurodevelopmental toxins
(such as ethanol and heavy metals). The authors conclude that "The potent
inhibition of this pathway by ethanol, lead, mercury, aluminum and thimerosal
suggests that it may be an important target of neurodevelopmental toxins."
Unfortunately, the authors tacked on the statement that "...vaccine
components (i.e. thimerosal and aluminum) may have contributed to the risk of
autism, ADHD and other developmental disorders."
We understand the pressures on scientists to justify the relevance of their
research and maintain funding of their work but the problem is that sometimes
basic research is just basic research and nothing more.
Barbara K. Hecht,
Ph.D.
Frederick Hecht, M.D.
Medical Editors, MedicineNet.com
Related Links
NEW RESEARCH SUGGESTS LINK BEWTEEN (sic) VACCINE INGREDIENTS AND AUTISM, ADHD
Exposure to certain neurotoxins may be linked to
development of dreaded
developmental disorders in children
(2-5-04) BOSTON, Mass. - According to new research from
Northeastern University pharmacy professor Richard Deth and colleagues from the University of
Nebraska, Tufts, and Johns Hopkins University, there is an apparent link between
exposure to certain neurodevelopmental toxins and an increased possibility of
developing neurological
disorders including autism and attention-deficit hyperactivity disorder. The
research - the first to offer an explanation for possible causes of two
increasingly common childhood neurological disorders -
is published today in the April 2004 issue of the journal Molecular Psychiatry.
Though some speculation exists regarding this link, Deth
and his colleagues
found that exposure to toxins, such as ethanol and heavy metals (including lead,
aluminum and the ethylmercury-containing preservative thimerosal) potently
interrupt growth factor signaling, causing adverse effects on methylation
reactions (i.e. the transfer of carbon atoms). Methylation, in turn, plays a
significant role in regulating normal DNA function and gene expression, and is
critical to proper neurological development in infants and children. Scientists
and practitioners have identified an increase in diagnoses of autism and ADHD in
particular, though the reasons why are largely unknown.
In their work, the scientists found that insulin-like growth factor-1 (IGF-1)
and the neurotransmitter dopamine both stimulated folate-dependent methylation
pathways in neuronal cells. At the same time they noted that compounds like
thimerosal, ethanol and metals (like lead and mercury) effectively inhibited
these same biochemical pathways at concentrations that are typically found
following vaccination or other sources of exposure. By better understanding what
happens when infants and children are exposed to these materials, the work of
Deth and his colleagues helps to explain how environmental contact with metals
and administration of certain vaccines may lead to serious disorders that
manifest themselves during childhood, including autism and ADHD.
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