Autism, luteolin and inflammatory markers

"We further show that the children with ASDs [autism spectrum disorders] in which the elevated serum IL-6 and TNF levels decreased at the end of the treatment period with a luteolin formulation, were the ones whose behavior improved the most."

That was an excerpt from the paper by Tsilioni and colleagues [1] (open-access available here) who looked at some of the potential biological (and behavioural) effects following supplementation with the dietary formulation known as NeuroProtek® [2] containing the flavonoid luteolin. Piggybacking on a previous open trial of luteolin [3] in relation to autism, authors report on levels of various serum cytokines between baseline and post-intervention as well as versus control specimens.

Levels of IL-6 (interleukin 6) and TNF (tumor necrosis factor) were reported to decrease in the autism group (N=38) following supplementation. Further, authors report on "two clusters of ASD children with low and high serum IL-6 and TNF levels indicating two subgroups." Specifically for those children with autism with higher values (n=10), they reported some interesting changes in scores on the Vineland Behavior Scales (VABS) suggesting that: "these children gained 9.73 months in the communication domain, 6.64 months in daily living skills and 8.09 months in the social domain."

These are intriguing results. Accepting the relatively small participant group and the open-trial methodology of the original study from which biological samples were derived, it strikes me that there may be quite a bit more to see from luteolin and related compounds when it comes to at least some autism. I'm not on this occasion going to focus too much on the cytokine results discussed by Tsilioni et al because I think there is more than enough peer-reviewed evidence implicating these various chemical messengers in at least some aspects of some autism (see here). I do think it is interesting however that the authors suggest that analysis of compounds like IL-6 and TNF might be one step towards looking for potential best responders to this type of intervention. Indeed, 'response to intervention' is something I'd like to see discussed a little more when it comes to teasing apart the different types of autism (see here).

I have mentioned luteolin previously on this blog (see here) and the link back to one or two of the authors on the Tsilioni paper including Prof. Theoharis Theoharides (he of mast cells and autism fame). "Luteolin is structurally closely related to 7,8-dihydroflavone, which was shown to have brain-derived neurotrophic factor (BDNF)-like activity" is one of the ways that the authors put forward as potentially being explanatory of their results, bearing in mind how 'mixed up' BDNF is when it comes to autism (see here). That and proposals for delivery via "intranasal administration" tapping into the rise and rise of pharmaceutical technology (see here) and I think we're going to be hearing quite a bit more about luteolin-containing preparations and autism in future research times...

Music: Sons of Pitches and a rather interesting version of MMMBop (in 10 genres).

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[1] Tsilioni I. et al. Children with autism spectrum disorders, who improved with a luteolin-containing dietary formulation, show reduced serum levels of TNF and IL-6. Transl Psychiatry. 2015 Sep 29;5:e647.

[2] Theoharides TC. et al. A case series of a luteolin formulation (NeuroProtek®) in children with autism spectrum disorders. Int J Immunopathol Pharmacol. 2012 Apr-Jun;25(2):317-23.

[3] Taliou A. et al. An open-label pilot study of a formulation containing the anti-inflammatory flavonoid luteolin and its effects on behavior in children with autism spectrum disorders. Clin Ther. 2013 May;35(5):592-602.

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Tsilioni I, Taliou A, Francis K, & Theoharides TC (2015). Children with autism spectrum disorders, who improved with a luteolin-containing dietary formulation, show reduced serum levels of TNF and IL-6. Translational psychiatry, 5 PMID: 26418275

Sera from children with autism inducing autistic features in rats?

"The autism sera injected rats demonstrated developmental delay and deficits in social communication, interaction, and novelty."

That was one of the findings reported in the paper by Syed Faraz Kazim and colleagues [1] (open-access) who, among other things, injected intracerebroventricularly sera collected from children with autism into newborn rats and examined behavioural effects compared with injections of sera from asymptomatic controls. Actually, that was only one part of the research from Kazim et al but it does invite some further interesting questions...

In brief, and bearing in mind the paper is open-access, a few details:

• A caveat first: "Based on studies described in this manuscript, the authors submitted a patent application to the United States Patent and Trademark Office on 12/11/2014, entitled: “Treatment of Autism Spectrum Disorders with Ciliary Neurotrophic Factor Peptide Mimetic”; application number US62/083,570; Inventors: Khalid Iqbal and Inge Grundke-Iqbal." The authors report a potential competing interest and good on them for doing so.
• As noted, there were several aspects to this research focused to a large extent around neurotrophins including something called ciliary neurotrophic factor (CNTF) or rather "a CNTF small peptide mimetic, P6" which might have the ability to increase levels of BDNF (brain derived neurotrophic factor ), a compound that has cropped up before on this blog (see here).
• So: sera from children with autism were initially added to "mouse primary cultured cortical neurons grown for 72 hours in medium" and resulted in "gross morphological changes". Pretreatment of said mouse neurons with P6 - "which corresponds to amino acid residues 146–156 of human CNTF" - seemed to have an effect that: "resulted in a significant reduction in cell death in cultured neurons treated with sera from autistic children." Another detail derived from this experiment: "Primary cortical neurons grown in the presence of autistic sera showed higher levels of oxidative stress." Interesting in light of other research in this area with autism in mind (see here)...
• Next: what was it in the sera from autistic children which seemed to be having effects on mouse neurons which weren't seen in control sera? Well it's possible that: "the presence of neurotrophic abnormalities in the sera from autistic children that could have contributed to altered development of neurons and increase in cell death and oxidative stress found." By neurotrophic abnormalities, the authors meant issues with "mature CNTF and BDNF" among other things.
• Next were the results from those studies where rat pups were injected with autism or control sera "with or without P6". More quotes: "alterations in the levels of neurotrophic factors in the sera from autistic individuals could contribute to neurobehavioral phenotype of autism in rats". By that the authors reported some potential differences in rat behaviour focused on things like grooming behaviour (repetitive behaviour) and ultrasonic calls (akin to social communication). P6 potentially rescuing functions was also reported for some of the tests.
• Conclusion: with the caveats of much more investigation required and that rats are rats and not humans (see here) "this study provides evidence regarding the neurotrophic abnormalities in autism and the potential role they play in the pathophysiology" of the condition. Further: "Ameliorating the neurotrophic imbalance during early stages of brain development can serve as a potential therapeutic approach for autism. P6 represents a new class of neurotrophic peptide mimetics that has potential therapeutic value for ASD and related conditions."

I'm rather interested in this work and the potential for at least some cases of autism as and when replicative work is undertaken. I note in other patents from this group (see here) the idea that peptides with a neurotrophic link might have some application to "neural pathologies where BDNF levels are dysregulated" is one that has been embraced.

The authors, the late Inge Grundke-Iqbal & Khalid Iqbal, have a pretty impressive peer-reviewed track record based to a large extent on their work on neurodegeneration and "abnormally hyperphosphorylated tau" as the main component of the tangles in Alzheimer's disease. Indeed, these findings have particular relevance recently (see here). Applying their, and their research groups, expertise to autism is most definitely an asset, albeit with the requirement for quite a bit more research in this area.

To close: The Stone Roses - She Bangs the Drums.

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 [1] Kazim SF. et al. Sera from Children with Autism Induce Autistic Features Which Can Be Rescued with a CNTF Small Peptide Mimetic in Rats. PLoS ONE. 2015; 10(3): e0118627.

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Kazim, S., Cardenas-Aguayo, M., Arif, M., Blanchard, J., Fayyaz, F., Grundke-Iqbal, I., & Iqbal, K. (2015). Sera from Children with Autism Induce Autistic Features Which Can Be Rescued with a CNTF Small Peptide Mimetic in Rats PLOS ONE, 10 (3) DOI: 10.1371/journal.pone.0118627

The mixed up world of brain-derived neurotrophic factor and autism

I have to say that I am becoming quite settled with my new found interest in blogging after some 16 months of running this blog. Indeed as hopeful as I am that my posts are accurate, balanced and of some interest to at least someone, the whole process of writing a blog entry is also quite good for me and my learning curve on the multitude of research that has been, and continues to be done on autism and things related. Makes you wonder whether blogging would ever count as CPD?

A case in point is this entry on the various research examining a role / connection between brain-derived neurotrophic factor (BDNF) and autism. I've heard mention of BDNF down the years but never considered myself to be fully capable of saying what the stuff is and what has been found in relation to autism. I'm trying to remedy that situation with this post, so let's see how I do.

BDNF is probably best described as a protein, a member of the neurotrophin family, and a growth factor for neurons and synapses. Quite a good overview of the neurotrophins can be found here* by Allen & Dawbarn (full-text). The link between BDNF and neuronal health is perhaps why the molecule has found quite a bit of interest in autism research circles and in particular, its proposed link to the serotonergic system - serotonin having quite a long history in relation to autism.

It is worth point out that BDNF levels and function are known to be influenced by several factors. So, age and gender seem to be able to affect levels of BDNF (here) as does specific pathology such as depression and schizophrenia (here) depending on where you look and what medium you look in. The neuronal 'plasticity' relationship to BDNF (among quite a few other actions I might add) seems to have been taken up by quite a few authors; particularly adult plasticity, contributory perhaps to the more lifelong view of brain plasticity which predominates these days over older theories of 'after childhood, set in stone'.

With autism in mind, there is a body of evidence on BDNF which suggests a few things albeit not exactly consistently:

• I am a little bit unsure whether BDNF is meant to be 'generally' high or low in cases of autism. Accepting the factors which can influence BDNF listed above, there seems to be some conflicting evidence on findings related to blood/plasma. So for example, this paper by Al-Ayadhi** (full-text), an author mentioned in previous posts, reported lower levels of serum BDNF in their cohort of children with autism. This contrasts with this paper by Connolly and colleagues*** who reported elevations in BDNF. Just to complicate matters further Lisa Croen and colleagues**** (full-text) reported no significant differences in blood concentrations of BDNF in either mums mid-pregnancy nor their young offspring subsequently diagnosed with autism compared with asymptomatic and learning disability control participants. I might be comparing apples and oranges at different times of year, but suffice to say that results are not yet clean-cut.
• When it comes to genes and BDNF in cases of autism, the waters aren't really any less muddy. This paper by Correia and colleagues***** reported elevations in plasma BDNF in their autism cohort but the source of the increase did not seem to stem from issues with the BDNF gene. Without being an expert on all things genetic, I think this finding might also tie into the results published by Garcia and colleagues****** who suggested that BDNF elevations might not be "transcriptionally driven" (see here for a summary of mRNA). There are other studies looking at other features of BDNF seemingly reporting contrasting findings such as decreased BDNF and anti-apoptotic function (here) and SNPs in the BDNF gene in autism (here and here). The message continues: it's complicated.

One could perhaps suggest that the various results relating to BDNF in autism mirror quite a few other areas of research insofar as not being able to make consistently reproducible statements of fact about autism. Having said that there are perhaps lessons to be learned from compounds such as BDNF in terms of fluctuating levels throughout the lifetime, differences depending on the tissue or biological medium being analysed and some degree of individual responsiveness behind the various findings so far. The fact that BNDF levels might also show involvement in other conditions, such as depression for example, is also worth bearing in mind.

Finally, and without trying to tie every single finding in autism back to gut bacteria or other of my areas of interest, there may yet be something in this relationship accounting for at least some of the BDNF findings in autism. I note for example this paper by Bercik and colleagues******* (similar work commented on here) which suggested that in mice at least, disruption of the gut microflora by antibiotic use seemed to increase brain levels of BDNF.

An example of a real gut-brain interface in action?

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* Allen SJ, Dawbarn D. Clinical relevance of the neurotrophins and their receptors. Clinical Science. 2006; 110: 175.191.

** Al-Ayadhi LY. Relationship between Sonic hedgehog protein, brain-derived neurotrophic factor and oxidative stress in autism spectrum disorders. Neurochemical Research. 2012; 37: 394-400.

*** Connolly AM. et al. Brain-derived neurotrophic factor and autoantibodies to neural antigens in sera of children with autistic spectrum disorders, Landau-Kleffner syndrome, and epilepsy. Biological Psychiatry. 2006; 59: 354-363.

**** Croen LA. et al. Brain-derived neurotrophic factor and autism: maternal and infant peripheral blood levels in the Early Markers for Autism (EMA) Study. Autism Research. 2008; 1: 130-137.

***** Correia CT. et al. Increased BDNF levels and NTRK2 gene association suggest a disruption of BDNF/TrkB signaling in autism. Genes, Brain & Behavior. 2010; 9: 841-848.

****** Garcia KL. et al. Altered balance of proteolytic isoforms of pro-brain-derived neurotrophic factor in autism. Journal of Neuropathology & Experimental Neurology. 2012; 71: 289-297.

******* Bercik P. et al. The intestinal microbiota affect central levels of brain-derived neurotropic factor and behavior in mice. Gastroenterology. 2011; 141: 599-609.