Scientific Blatherings: Debunking Rivera: The Blood Brain Barrier
During the course of my review series of Healing the Symptoms Known as Autism; several scientists have approached me offering up their knowledge and expertise in their various fields to help me debunk some of the outrageous claims made throughout the course of the text. Being merely an engineer, I have not the skill and expertise to dabble in the many different fields to debunk the many assertions made. Suffice it to say I have gladly accepted the help that has been offered up to me! The first in this series of real scientists debunking Rivera’s work merely wants to be credited as Scientist Abe. What now follows is his critique of some of the absurd statements made during chapter 3 about the Blood Brain Barrier and how kids with Autism are affected by the food they eat as components in their food somehow crosses this elusive barrier.
In this chapter, Kerri Rivera takes questionable approach on linking exorphins with autism citing scientific studies that link .
ASD with high levels of peptides citing two references as a sole source for her statement: the study from Reichelt and colleagues and the review from Shattock and colleagues.
Firstly, the citation of Shattock review is outdated and only provide an exhaustive overview of published studies supporting or dismissing the theory of opioid-excess. It has no scientific value as it does not provide a direct evidence of such claim. More troublesome is the following study led by Hunter and colleagues published by Hunter and colleagues in 2003 investigating the presence of opioids mimetics in patients urine and published in Developmental Medicine & Child Neurology, a journal with an acceptable impact factor (IF=3.29).
Using liquid chromatography coupled with mass-spectrometry (a common analytical technique used for measuring metabolites in biological fluids), the authors have investigated the presence of opioids in a cohort of 10 children with ASD and used siblings as controls. Interestingly, the authors failed to notice notable differences (as defined by presence of unique peaks) in the urine chromatogram of ASD children compared to controls. The authors further investigated the presence of opoid peptides previously cited by Shattock, in particular beta-casomorphin (a peptide byproduct obtained from casein degradation) and alpha-gliadin (a peptide byproduct obtained from gluten degradation). The authors failed to identify the presence of both peptides, based on retention time compared to standard or based on the m/z index.
This publication irated enough Shattock to be followed by a comment to Editor and a scientific joust between Shattock and Hunter, however an editorial published by John F Mantovani resumes well the context in which the initial statement of Shattock was published. At this time, ASD etiology was completely unknown and remained highly speculative. The publication (and subsequent retraction) of the so-called “Wakefied study” linking MMR vaccines to ASD cases, but also documenting the presence of inflammatory bowel disorder in ASD patients, such condition is known to triggered by gluten and casein in patients suffering from celiac diseases. As Mantovani mentioned, the adoption of the theory of gluten and casein was correlating with the same approach than the vaccine without any scientific rationale.
The study from Hunter indeed showed the lack of evidence about the claim made by Shattock. The amount of studies linking autism and exorphin remains very low. A query on Pubmed (the database of the National Library of Medicine) using the keywords “autism” and “exorphin” results in only 7 publications with 3 publications from Reichelt, KL and two publications from Brudnak, MA.
This brings the concern of data reproducibility. In order to have a scientific claim that have strong significancy you need two factors: a significant number of publications that investigated such statement and the publications of findings from different research groups. Having the monopoly of such investigation solely on a single research laboratory raises the issue of data reproducibility and reliability.
In this case, the study of Reichelt is very interesting, as its publication quality appears dubious at different levels. The journal of Microbial Ecology and Health Disease has recently adopted the “open-access” policy. Prior its publication as open-access, the journal has an 2013 unofficial impact factor of 0.933. The “open access” and the low IF raise red flags: such journal may be a potential “predatory journal” (a term coined by Retractionwatch.org, a website tracking scientific articles retraction). In this model, the cost of open-access is levied by the payment of hefty publication fees ($3000-5000) usually higher than subscription-based journals. Because of such financial gain, the peer-review process may be altered and even may be completely omitted, removing the quality control accomplished by peer-review. This lack of peer-review process is particularly blatant by the absence of clearly structured “methods” sections, odd wordings for a scientific (“ELISA typed as Elisa, thaw over night, eight-hundred microliters”), the source of samples (Association Planet Autism (Italy), samples from Slovenia, Serbia and Australia) and the overall format of the paper figures with some appearing as a screenshoot of a Powerpoint presentation or from printed copies. It raises some skepticism about why the author (based in Norway) failed to collect samples from Norwegian ASD patients.
Based on these flawed scientific background, Rivera continues on linking these studies to a “leaky bowel syndrome”. A major flaw in this claim is the absence of citing the original publication for Hsaio and colleagues that have demonstrated the presence of a “leaky gut syndrome” in mice showing an ASD phenotype. Instead Rivera cites the Gluten Free Society webpage as a source of information (http://www.glutenfreesociety.org/gluten-free-society-blog/dr-fasano-on-leaky-gut-syndrome-and-gluten-sensitivity/).
Dr. Alessio Fasano is certainly a respected researcher in celiac diseases but as noted with pseudoscience and activists groups lacking the scientific knowledge, cherry-picking and extraordinary extrapolation. In particularly in this case by the Gluten Free Society, those as their Facebook webpage mentions, identify themselves as alternative and holistic health society. This is again a red flag on the mission and purpose of this society that have little or no scientific evidence to support their claims except deviating, cherry-picking and reformulating genuine studies to push for their agenda.
Under normal conditions, the intestinal and the blood-brain barrier (BBB) (Figure 1) provides a tight cell monolayer creating a gut-blood and a blood-brain barriers respectively. Under normal conditions, such barrier is achieved by the presence of tight junctions complexes stopping the diffusion of electrolytes and water between the two compartments. Only digestion byproducts such as amino-acids or glucose are transported through dedicated nutrient transporters or solute carriers, whereas bigger entities such as peptides, proteins and pathogens have virtually no diffusion). Only lipids (fatty acids, cholesterol…) and drugs (designed as lipid-soluble chemicals) can passively diffuse across the barrier by mixing themselves with the phospholipid bilayers making the cell membranes.
In the study from Hsiao, the authors demonstrated indeed the presence of a “leaky gut” as measured by an increase in FITC-dextran permeability with an estimated size of 4kDa (that’s about the size of a peptide of 36 amino acids). See More