The Autism Research Agenda- The wide range of dysfunctions partly explains why it is difficult to treat and why we must treat the individual and not the diagnosis
Environmental toxins; Considerable research activity is being conducted into the roles of environmental toxins in autism. The increased mercury (Hg) body burden, whether derived from thimerosal in vaccines, elevated levels in the environment/food chain or a decreased ability to eliminate Hg from the body, or indeed all three, remains an important research topic. However, Hg is not the only important elemental toxin as arsenic, antimony, lead, tin and aluminium are also neurotoxins both individually and collectively. As these are often controversial, due to vaccine inclusion or environmental contamination, their study and implication as causative factors has been largely ignored by mainstream research. In addition, to elemental inorganic toxins the organic pollutants, including dioxins, PCBs and organochlorine and organophosphate pesticides have also been implicated in neural disorders. In particular, the polybrominated biphenyl ethers (PBDEs), that have been used as flame retardants since the 1980s, have recently been implicated in the rise of autism due to their increased use paralleling the increase in autism diagnosis post-1985 as well as their known effects as endocrine disruptors and pro-oxidants.
Following on logically from environmental toxins is the issue of increased pro-oxidant activity or reduced antioxidant activity which has been recorded by numerous autism researchers in particular by Dr Jill James and co-workers.
Pro-oxidants increased oxidative damage to cells and tissues and result in inflammation. The metabolism of inorganic and organic toxins can promote oxidation and subsequent reduction of protective antioxidants that ultimately results in inflammatory reactions that damage cells, tissues and enzymes etc. Pro-oxidants can arise from other sources apart from toxins and their activity may be exacerbated by metabolic deficiencies in patients with autism. These include problems with methylation and transulphuration activities that have been identified in patients with autism and can disrupt metabolism, particularly related to detoxification as well as direct damage to DNA. Considerable research in this area has been conducted by Dr Richard Deth and co-workers.
One method of improving methylation activity that has aroused considerable research interest has been the use methyl-vitamin B12, either as an intra-muscular injection or as a nasal spray. Many patients with autism have shown great benefits from this therapy and future research would look to improve methodologies as well as more effectively target the responders from within the autism spectrum.
Obviously cellular damage that increases inflammation is also relevant to the occurrence of GI problems in autism and may result in enterocolitis but inflammation can be much more extensive in autism affecting all tissues including the brain thereby affecting neuronal signalling as well as immune functions that rely on controlled oxidation to identify and eliminate pathogens as well as maintaining a balance between the pro- and anti-inflammatory cytokines that are vital in immune integrity.
Inflammation is also implicated in the response to viral infection, including measles, rubella and others. Research has investigated methods of reducing viral body burdens by attenuating damage and promoting the bodies healing mechanisms. One of these has lead to the use of high dose vitamin A thereby as a method of viral removal in children with autism as described by Drs MacCandless, Baker and others.
Related to oxidative tissue damage and inflammation has been the recent pioneering work using HyperBaric Oxygen Therapy (HBOT) as a means of reducing damage to the body arising from inflammatory activity. The treatment involves subjecting the patient to increased levels of oxygen, at increased pressure in a hyperbaric chamber for several hours. The early results of this therapy look promising and we await the results of future research with great interest.
Another important area of research has been the development of chelation therapy to remove the elemental toxins described above. This has involved the use of oral, transdermal and IV administration of chelating agents that enter cells and bind to HG, Pb etc and allow their excretion in urine and faeces. The use of these compounds is not without risk but providing appropriate monitoring measures are used on a routine basis to assess patient health they can often bring great benefits in health and behaviour in individuals with autism.
While there is no doubt that the use of a gluten/casein-free (GF-CF) diet can benefit a great many children with autism the mechanism of action as well as the number of children who benefit still remains controversial and is the subject of ongoing research. The opiod peptide theory, as suggested by Shattock and co-workers, has never been convincingly proved and it is important for the adoption of this dietary intervention into mainstream medicine that research on the therapeutic mechanism of this diet is conducted in the near future. In addition to the GF-CF diet other restricted nutrient diets including the low oxalate, ketogenic and Specific Carbohydrate diets (SCD) have also proved beneficial for some patients with autism but more research is required to prove their efficacy and mechanism of action.