Another excellent article by Prometheus.
January 2nd, 2009
Practitioners that promote the “biomedical” treatment of autism often claim that there is little risk of harming an autistic child with the interventions they recommend. “What’s the harm of trying?”, they ask; “What have you got to lose?”
As it turns out, the answer to that question may be “Quite a bit.” Apart from the cost in terms of money, time, effort and false hope, it now appears that one of the prominent “biomedical” treatments for autism may cause neurological damage.
In November, 2008, the journal Neurotoxicology released an “e-publication” of an article that casts further doubt on the efficacy and safety of chelating children with autism.
Rush T, Hjelmhaug J, Lobner D. Effects of chelators on mercury, iron, and lead neurotoxicity in cortical culture. Neurotoxicology. 2008 Nov 5. [Epub ahead of print]
In this study, the authors used primary cortical cell cultures to study the effectiveness of several chelators commonly used to treat “heavy metal poisoning”: calcium disodium ethylenediaminetetraacetate (CaNa(2)EDTA), D-penicillamine (DPA), 2,3 dimercaptopropane-1-sulfonate (DMPS), and dimercaptosuccinic acid (DMSA). All but DPA have been widely used to “treat” autistic children.
They treated the primary cortical cell cultures with four metal “toxicants”: inorganic mercury (HgCl2), methylmercury, ethylmercury (thimerosal!), lead (PbCl2) and iron (Fe-citrate) and then with one of the four chelators (and one control group that received the metals but no chelator). Their results may surprise some people.
DPA performed the worst of all, providing no protection and actually increasing the toxicity of inorganic mercury, thimerosal and iron. EDTA reduced the toxicity of inorganic mercury but “caused a severe potentiation” of iron toxicity.
Both DMPS and DMSA reduced inorganic mercury toxicity but increased the toxicity of thimerosal and iron. DMPS (but not DMSA) increased the toxicity of lead.
Now, these aren’t the results we have been led to expect. [Note: potential understatement of the year candidate]
If this had been the only study to suggest that chelation was potentially dangerous, I would be willing to shrug it off. After all, it is in cell culture, which is a questionable analogue for the intact organism. However, there have been two other studies looking at living organisms that have results consistent with the findings of Rush et al.
Dietrich et al (2004) showed that treating children with blood lead levels between 20 and 44 mcg/dl with DMSA [Note: chelation therapy with DMSA is recommended for blood lead levels of 45 mg/dl and above but not specifically recommended - or contraindicated - for blood lead levels from 10 - 44 mcg/dl] had no effect on a variety of neurocognitive tests at long-term follow-up (4 - 5 years).
However, they found a statistically significant decrease in attention and executive functions in the children treated with DMSA when compared to placebo. Given the nature of neurocognitive testing and the variation in genetic and environmental factors in humans, this result was not given a great deal of weight at the time.
In 2007, Stangle et al showed that DMSA, when given to rats that were truly lead-toxic (i.e. blood levels in the toxic range without “provocation”) improved learning and etc., but that when they gave it to rats that did not have toxic lead levels (i.e. the control group), there was a significant and sustained (i.e. permanent - it did not disappear during the duration of the study) decrease in cognitive function.
What does all this mean to parents who are - or are contemplating - chelating their autistic children? Well, it strongly suggests:
 Chelation with EDTA, DPA, DMPS and DMSA does not “work” for organic mercury, such as ethyl mercury from thimerosal. The Rush et al study was particularly pertinent to parents who think their children became “mercury poisoned” from thimerosal-containing vaccines, since it used thimerosal as the source of ethyl mercury.
 Giving DMSA or other chelators to children who do not have significant blood levels of heavy metals is likely to cause brain damage. It is probable that the chelating agents cause some degree of neurological damage, but that higher lead (or other heavy metal) levels cause sufficiently greater damage that the chelators are the “lesser of two evils”.
Many parents (and not a few practitioners) have argued, “Chelation is safe; why not give it a try? It can’t hurt and it might just help.” Well, now we have a growing body of data suggesting that chelation might not only be ineffective, it might make your child worse.
Since many practitioners following the “DAN! Protocol” or similar regimens commonly give chelating agents when (unprovoked) blood/urine levels of mercury (or other metals) are well below the toxic range, these studies are directly applicable to this practice.
An additional concern is that practitioners (and do-it-yourself parents) who chelate to “treat” autism often continue giving these drugs for years. Even the treatment of lead toxicity - which takes much longer since lead is incorporated into the bones - is usually limited to six months to a year, with careful monitoring.
People who may be tempted to smugly ignore these warnings because they are using “natural” chelating agents or other agents not mentioned in these studies should rethink their complacency. The mechanism that causes the cognitive impairments seen after DMSA treatment - and the toxicity to cell cultures seen after DPA, EDTA, DMSA and DMPS treatment - is unknown. It may well be that any heavy metal chelating agent can cause the same injury.