Thursday, 4 July 2013

sPECAM pie and school-aged autism

I've talked about adhesion molecules with autism in mind before on this blog (see here). In that entry it was some interesting data out of the MIND Institute which caught my attention; specifically the selectins and their sticky siblings being 'generally' suggested to be lower in case of autism than control samples. Without repeating my previous post, it's all about the binding of leukocytes to the walls of blood vessels to begin their rolling journey towards the site of an injury and then inflammation, yadda, yadda...
Rolling stone & moss @ Wikipedia  

Anyhow, a new addition joins the voices suggesting issues with adhesion in cases of autism in the form of the paper by Yosuke Kameno and colleagues* (open-access paper available here).

The Kameno paper fills a bit of a gap in the literature in this area by looking at levels of platelet-endothelial adhesion molecule-1 (PECAM-1), platelet selectin (P-selectin), endothelial selectin (E-selectin), intracellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in serum samples from school-aged children (5-17 years old) diagnosed with autism compared with asymptomatic controls. The reasoning being that very young infants and young adults have been examined with these adhesion molecules in mind but not the intervening age group.

The results: well probably unsurprisingly, levels of at least some of the adhesion molecules were lower in cases of autism compared with the control group. So: "The serum levels of sPECAM-1 in subjects with high-functioning ASD were significantly lower than those of controls (U = 91.0, P<0.0001) (Table 1). Subjects with high-functioning ASD also had significantly decreased levels of sVCAM-1 compared with those in controls (U= 168.0, P = 0.0042)". The U by the way refers to the statistical test used (Mann-Whitney U test) to analyse results. That and the fact that attempts to correlate the biological findings with things like scores on the Autism Diagnostic Interview-Revised (ADI-R) didn't reveal any significant correlations.

There are also a few hidden gems in this paper not readily discussed too much. So for example: "To exclude inflammatory disease, serum C-reactive protein (CRP) levels were determined". CRP is another interesting compound which I've talked about before with regards to inflammation and autism or risk of autism (see here and here). Kameno didn't seem to find anything specific in their autism cohort aside from: "The CRP measurement of one subject with ASD was 2.30 mg/dl (this individual did not have subjective symptoms or a history of inflammatory disease)".

They also looked at a number of cytokines in their participant group and concluded: "We determined that plasma concentrations of IL-1β, IL-1RA, IL-5, IL-8, IL-12(p70), IL-13, IL-17 and GRO-α were 
significantly higher in subjects with ASD compared with the corresponding values of the matched controls, after correcting for multiple comparisons". I'm particularly interested in their observations on IL-17 given some previous work in this area (see here) and its [proposed] link to various autoimmune conditions.

So Kameno and colleagues have filled the age group gap in the work looking at adhesion molecules with autism in mind. Given the increasing strength of the evidence coming out of this area of autism research, one could make a good argument for quite a bit more detailed investigation?

To finish, there are potentially lots of rolling linked songs I could offer. But instead I'll go for burning....

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* Kameno Y. et al. Serum levels of soluble platelet endothelial cell adhesion molecule-1 and vascular cell adhesion molecule-1 are decreased in subjects with autism spectrum disorder. Mol Autism. 2013 Jun 17;4(1):19.

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ResearchBlogging.org Kameno Y, Iwata K, Matsuzaki H, Miyachi T, Tsuchiya KJ, Matsumoto K, Iwata Y, Suzuki K, Nakamura K, Maekawa M, Tsujii M, Sugiyama T, & Mori N (2013). Serum levels of soluble platelet endothelial cell adhesion molecule-1 and vascular cell adhesion molecule-1 are decreased in subjects with autism spectrum disorder. Molecular autism, 4 (1) PMID: 23773279