Sunday, 22 December 2013
Friday, 20 December 2013
Amyloid may sound like someone’s name, but in fact it is something rather sinister and is related to many brain disorders. It appears that, at least in severe cases, they may be implicated in autism, or least the precursor is.
Proteins that are normally soluble undergo a process called amyloidosis, which makes them insoluble and allows deposits to accumulate in various organs, including the brain. There are many known examples, including Alzheimer’s and Mad Cow Disease (Creutzfeldt–Jakob disease). A number of years ago there was a huge public health scare in the UK, when humans were affected by Mad Cow Disease, after eating the brains of cows in processed food.
Symptoms vary widely, depending upon where in the body amyloid deposits accumulate. Amyloidosis may be inherited or acquired.
The precursor to amyloid is naturally called Amyloid Precursor Protein (APP).
APP exists in all of us and is not necessarily bad. Its function is not fully understood (see later in this post).
Affects female > Mmale Affects male > female
Brain atrophy Macrocephaly
(enlarged brain in child)
Degenerative Decline followed by stable
High αβ, low sAPPα High sAPPα, low αβ
Amyloid Precursor Protein (APP)
The gene related to Amyloid Precursor Protein (APP), was only identified in 1987 and the biology surrounding it is only very partially understood. Much of the experimental work is related to Alzheimer’s, but some of these researchers are also looking at implications for autism.For the bold, here is a very recent paper on APP:-
A power-point style presentation is here:-
The research proved the hypothesis:-
APP metabolites follow nonamyloidgenic pathway (i.e., high sAPP, sAPPα, low Aβ 40) in brain tissue of children with autism, compared to age matched controls
Here is the data:-
For those of you who want to read a full paper by the same authors from Indianapolis, here it is:-
Increased Secreted Amyloid Precursor Protein-a (sAPPa) in Severe Autism: Proposal of a Specific, Anabolic Pathway and Putative Biomarker
TerminologyBiologists do make their work sound very complicated; generally it is the terminology that may make it look unintelligible on first reading. Just read it again and look up the confusing terms. They also seem to have up to 5 different names for the same molecule.
Compared to other areas of science like Fluid Mechanics, which I had to study, and Wikipedia rather understated describes as “Fluid mechanics can be mathematically complex”, biology is just a lot of knowledge; none is really intellectually challenging, at least not until the amyloids start growing.Just use the amazingly up to date resources of Wikipedia.
Aβ = beta amyloid = amyloid β-peptide The most common isoforms are Aβ40 and Aβ42
βAPP = β-amyloid precursor protein = amyloid-β precursor protein = AβPP
sAPPα = soluble APPα = soluble amyloid precursor protein α
β-secretase = Beta-secretase 1 = BACE1 = beta-site APP cleaving enzyme 1 = beta-site amyloid precursor protein cleaving enzyme 1
γ-secretase = Gamma secretase
Gamma secretase can cleave APP in any of multiple sites to generate a peptide from 39 to 42 amino acids long.
Generation of the 42 Aβ (amyloid β-peptides) that aggregate in the brain of Alzheimer's patients requires two sequential cleavages of APP. Extracellular cleavage of APP by β-secretase (BACE) creates a soluble extracellular fragment and a cell membrane-bound fragment referred to as C99. Cleavage of C99 within its transmembrane domain by γ-secretase releases the intracellular domain of APP and produces Aβ (amyloid-β).
However a single residue mutation in APP reduces the ability of β-secretase to cleave it to produce amyloid-beta and reduces the risk of Alzheimers and other cognitive declines.Inhibitors of amyloid deposition include the enzymes responsible for the production of extracellular amyloid such as β-secretase and γ-secretase inhibitors. Currently the γ-secretase inhibitors are in clinical trials as a treatment for Alzheimer's disease.
Amyloid Precursor Protein
Amyloid precursor protein (APP) is an integral membrane protein expressed in many tissues and concentrated in the synapses of neurons. Its primary function is not known, though it has been implicated as a regulator of synapse formation, neural plasticity and iron export. APP is best known as the precursor molecule whose proteolysis generates beta amyloid (Aβ), a 37 to 49 amino acid peptide whose amyloid fibrillar form is the primary component of amyloid plaques found in the brains of Alzheimer's disease
Although the native biological role of APP is of obvious interest to Alzheimer's research, thorough understanding has remained elusive.
Synaptic formation and repair
The most-substantiated role for APP is in synaptic formation and repair; its expression is upregulated during neuronal differentiation and after neural injury. Roles in cell signalling, long-term potentiation, and cell adhesion have been proposed and supported by as-yet limited research. In particular, similarities in post-translational processing have invited comparisons to the signaling role of the surface receptor protein Notch.
APP knockout mice are viable and have relatively minor phenotypic effects including impaired long-term potentiation and memory loss without general neuron loss. On the other hand, transgenic mice with upregulated APP expression have also been reported to show impaired long-term potentiation.
The logical inference is that because Aβ accumulates excessively in Alzheimer's disease its precursor, APP, would be elevated as well. However, neuronal cell bodies contain less APP as a function of their proximity to amyloid plaques. The data indicate that this deficit in APP results from a decline in production rather than an increase in catalysis. Loss of a neuron's APP may affect physiological deficits that contribute to dementia.
A different perspective on Alzheimer's is revealed by a mouse study that has found that APP possesses ferroxidase activity similar to ceruloplasmin, facilitating iron export through interaction with ferroportin; it seems that this activity is blocked by zinc trapped by accumulated Aβ in Alzheimer's. It has been shown that a single nucleotide polymorphism in the 5'UTR of APP mRNA can disrupt its translation.
The hypothesis that APP has ferroxidase activity in its E2 domain and facilitates export of Fe(II) is possibly incorrect since the proposed ferroxidase site of APP located in the E2 domain does not have ferroxidase activity.
The amyloid-β precursor protein (AβPP) and all associated secretases are expressed early in development and plays a key role in the endocrinology of reproduction – with the differential processing of AβPP by secretases regulating human embryonic stem cell (hESC) proliferation as well as their differentiation into neural precursor cells (NPC). The pregnancy hormone human chorionic gonadotropin (hCG) increases AβPP expression and hESC proliferation while progesterone directs AβPP processing towards the non-amyloidogenic pathway, which promotes hESC differentiation into NPC.
AβPP and its cleavage products do not promote the proliferation and differentiation of post-mitotic neurons; rather, the overexpression of either wild-type or mutant AβPP in post-mitotic neurons induces apoptotic death following their re-entry into the cell cycle. It is postulated that the loss of sex steroids (including progesterone) but the elevation in luteinizing hormone, the adult equivalent of hCG, post-menopause and during andropause drives amyloid-β production and re-entry of post-mitotic neurons into the cell cycle.
Recently, amyloid precursor protein (APP) origin was demonstrated with arthritogenic animals. The source noted is breakdown of immune complexes, where the amyloid aggregates are left degraded and bind together to form coil like structures that are not reabsorbed. Also, it induces secondary inflammation, which may cause local damage.
ADAM17ADAM17 is understood to be involved in the processing of tumor necrosis factor alpha (TNF-α) at the surface of the cell. This process, which is also known as 'shedding', involves the cleavage and release of a soluble ectodomain from membrane-bound pro-proteins (such as pro-TNF-α), and is of known physiological importance. ADAM17 was the first 'sheddase' to be identified, and is also understood to play a role in the release of a diverse variety of membrane-anchored cytokines, cell adhesion molecules, receptors, ligands and enzymes.
Amyloid Precursor Protein (APP) can either be processed towards so-called amyloidogenic pathways in the brain that lead to Alzheimer’s, or it can follow so-called non-amyloidogenic pathways, as appears to be the case in autism. The direction taken seems to depend on α, β and γ–secretases, which are themselves regulated by neurotransmitters and other signalling molecules.But why are there elevated levels of APP in autism?
As is often the case in autism research, some are thinking biomarker and some are thinking about therapeutic interventions. I am with the latter.
By the way, now we have dealt with Amy, what about Adam? (the final chart above)Functional ADAM17 has been documented to be expressed in the human colon, with increased activity in the colonic mucosa of patients with ulcerative colitis, a main form of inflammatory bowel disease. But remember, that paper by Wakefield was retracted and so there should not be evidence linking autism with colitis. Tell Adam to keep quiet.
ADAM17 = ADAM metallopeptidase domain 17 = TACE = (tumor necrosis factor-α-converting enzyme) = TNF α-converting enzyme
TNF are a group of cytokines that cause cell death.
TNF are a group of cytokines that cause cell death.
Wednesday, 18 December 2013
For the psychologists among you, and self-taught ABA parents like me, you will know what is a meant by an "acquired behaviour". So once a child has learnt a behaviour, that resulted in something the child found rewarding, the behaviour will repeat.
Once learnt, it is difficult to get rid of unwanted acquired behaviours. An example in autism would be self-injury.
In an earlier post, we learnt that children at risk of developing asthma, if identified and treated with a mast cell stabilizer, could be prevented from developing asthma. Once you have had one asthma attack, more will follow.
Today, I learnt that you can acquire a channelopathy, that is to say an ion-channel disease that is normally caused by your genes.
"We do know that in some forms of epilepsy, once someone has a seizure they tend to have more. Our findings from this study suggest that something about the brain changes that can lead to this increased tendency to have a seizure. Our study shows that an important change occurs in calcium channels that help to transmit this abnormal activity throughout the brain."This means, at least in some types of epilepsy, the first seizure permanently changes (damages) the brain. Thereafter, the affected ion channels function as if that person had a gene mutation.
This is important for the study of autism because we know that there are ion-channel abnormalities. If you could identify these channelopathies, that would be the first step towards treating them, and reversing the associated behaviours.
If these channelopathies were not predetermined by genetics, rather some were acquired, that would be very important. Then you could look at how, when and why they were acquired.
It might be that the channelopathies caused by rare inborn genetic mutations associated with conditions like Timothy Syndrome, are not so rare after all. It is just that the channel mutated without the "faulty" gene. So genetic testing will not identify it.
Tuesday, 17 December 2013
For parents more severely affected by autism, one of the most difficult things to deal with is anger, aggression and self-injurious behaviour (SIB). SIB is sometimes rather politely referred to as challenging behaviour.
In the case of Monty, aged 10 with ASD, we have overcome these problems (for now at least); but for other people have to struggle on with them, on a daily basis.
SIB can affect any person with autism, whether they are severely, moderately or mildly affected otherwise. Left untamed, I am reliably informed, it may return in adulthood.
So, for those people, who do not want to follow the “novel”, but science-based, interventions discussed elsewhere in this blog, here is what the experts have to say:-
From the US (an excellent paper) :-
From the UK:-
Monday, 16 December 2013
We have a cleaning lady who comes each week to help keep our house in order. She also understands the value of comorbidities. She is one of my independent observers, in changes in the behaviour of Monty, aged 10 with ASD. She has a friend, whose husband was diagnosed with early-onset Alzheimer’s.Alzheimer’s is not autism, but they are both examples of brain damage.
Still in his early 50s, the husband does not recognize his children and cannot leave home. The expert Professor, treating him privately, was not halting the rapid decline.So the cleaning lady asks me about all my investigations and decides that she might as well tell her friend. She decided to suggest the antioxidant NAC and the cholinergic stimulant nicotine.
Well, after NAC, the husband was able to make it to the WC and do his business. A small step forward.After a day with the nicotine patch, things really changed so much that the family decided that they should seek a second opinion, this time from a doctor, yet to publish a book.
Doctor number two decided that it is not Alzheimer’s after all, and the prescribed medicines of the last three years were only making things worse. And the new therapy? Nicotine patches.
ConclusionThe conclusion is self-evident.
The next related conditions I will be investigating are cluster headaches, febrile seizures and absence seizures.
Wednesday, 11 December 2013
In earlier posts I have touched upon the problems of clinical trials in autism:-
· Highly subjective, or ineffective, rating scales for autistic behaviours
· Lack of biomarkers, or any other marker, to target a specific sub-types(phenotypes of autism
· Very small sample sizes and often amateur execution, meaning the results cannot be replicated
I think one of these problems has a ready solution, at least for verbal primary school children with ASD.
Last week, Monty aged 10 with ASD, had assessment week at school. The academic subjects he participates in, are Maths, English and Science. We have chosen to skip Geography, History and French. Monty already has another second language.Following the tests at school, I decided to make a test of my own. I stopped all of my therapies and waited to see what would happen and if anyone would notice.
The first therapy I had to reintroduce was bumetanide, which in his case makes him far more aware of himself and his surroundings; it makes him more “present”. The reason for this was, for the first time in years, on day one, he forgot to go to the toilet and peed in his pants. A coincidence? I think not. Also, when I told him that I was going out, instead of the expected “see you later, Dad” I got “see you Monday”.Then the next day having restarted bumetanide we drive to school. I hear lots of relevant comments like “There’s a Peugeot lion taxi car”, “The soldier has a gun, that fires bullets”. The day before there were no comments at all.
But the day at school was not so good; all the stereotypy with his hands and fingers returned, so while the day was not hard for his assistant, she said it was hard for Monty. He was commenting, like the things he could see through the window of his classroom, but work was not good. Handwriting degenerated to oversized sloppy writing, that did not follow the lines on the paper. In the afternoon, I reinstated NAC, just in time for the arrival of his assistant who works with him at home, following an ABA-style programme. During the rest of the afternoon, all stereotypy with his hands and fingers disappeared, just as expected.Today, I met the school teacher and not only were his grades As and Bs, but he finished his tests much faster than most of the other children. This is remarkable, because he has never received any real academic grades before; the teachers did not think it fair to give him grades. I should point out that Monty is at least 2 years older than his classmates; but then he was pretty much entirely non-verbal until he was 4 years old, so he has lost a lot of learning time.
The relevance of all this is that while psychological and behavioral testing is very subjective, basic cognitive testing, as practiced in schools around the world, is very well understood, fair and easy to replicate.With children who are verbal, can read a bit, write and do some very basic maths, a simple cognitive test, measuring these basic skills, assessing both accuracy and speed would produce a pretty good surrogate index of cognitive functioning. You could easily use such an index to measure the effectiveness of a drug in autism. If large scale trials were done in Special Schools, this could work really well. One week the class is on the placebo and the next week on the trial drug. Then you could have trials with several hundred participants.
I think coming up with measurements for things like “social withdrawal”, as is currently done, is far too esoteric. Let’s go back to the three Rs (reading, writing and arithmetic).
Nootropic drugsI find it more than a coincidence that several of the autism drugs I am investigating, happen to be classed as nootropic. Nootropic drugs are cognitive enhancers.
I have demonstrated that as you improve autism, you increase cognitive function; but perhaps as you improve cognitive function, you improve autism. If this were true, it would open up new avenues for investigation.There is an underground scene of cognitive enhancers, and if you probe the internet, you will readily find what works and what does not.
On the serious research front, here is a recent paper that is very comprehensive:-
Cognitive Enhancers (Nootropics). Part 3: Drugs Interacting withTargets other than Receptors or Enzymes. Disease-modifying Drugs
Tuesday, 10 December 2013
With a title like that, not many people will stumble upon this post with Google.
So, for the hard-core of readers, today I am going to develop an idea of Martha Herbert, the pediatric neuroscientist from Harvard, who writes a lot about autism.
Incidentally, most researchers do not like publicity, and particularly those looking at autism. Martha, herself makes some side remarks as to why this is; as I suggested in earlier posts it dates back 10+ years to a certain Dr Wakefield.
“A further barrier to considering the body’s impact on the brain was the reaction to the work of Wakefield, who argued not only that there was a link between autism and vaccines but also that this link was mediated through the gastrointestinal system. For the better part of a decade any attempt to discuss gastrointestinal or immune issues with autism was construed as a support of Wakefield’s vaccine hypothesis, and it was difficult to discuss, let alone get funding for, clinical or research observations about these problems. One way around the essentially taboo character of somatic problems in autism was to treat them as coincidental symptoms. For example, one could talk about gut problems provided one made it clear that they did not cause the autism in the brain. Improvement after treatment of gut problems, which is often observed, would then be explained as a consequence of reduction of pain and discomfort, but not of any direct impact on core brain mechanisms generating autistic behaviors.”
Another fearless autism researcher, not shy to voice his opinions by blog and tweet, is Paul Whiteley, in Sunderland. Paul is very much a believer in the role the gut/diet in autism, he and Paul Shattock are the driving force behind the gluten and casein free diet as a therapy for autism. Given what Martha writes above, and the association between Shattock and Wakefield, is it surprising that the GCF diet remains on the fringes? I know some parents who wholly endorse it.Here is a link to one of Martha’s recent works, for Herbert fans:-
Dynamic EncephalopathyIt was Martha who called autism a dynamic Encephalopathy. Encephalopathy just means a brain disease.
What she means is that over time autism changes, day to day and year to year. Just as during fever, autism symptoms may wane, other environmental provocations may cause flare ups. With age come hormonal changes that will inevitably change the central hormonal homeostasis, I hope for the better, as generally is the case.Other than being a fancy word, Encephalopathy, is probably a much better word than autism. There are many types of Encephalopathy and there are multiple causes, it refers to a syndrome of global brain dysfunction; this syndrome can have many different organic and inorganic causes. As with autism the hallmark of encephalopathy is an altered mental state.
Forget Autism think Encephalopathy
If you have not already opened up Wikipedia, I suggest you do.
From my desk research and primary research, I know that one factor behind this encephalophy is chronic inflammation, otherwise known as neuroinflammation.At this point, we should look at what neuroscience can tell us about neuroinflammation
The Dana Foundation is a private philanthropic organization committed to advancing brain research. Founded in 1950 and with $230+ million in assets I think they should be a good source. Here is an excellent paper, that is written for non-scientists.
Among the many interesting insights are these:-
“Until recently the CNS and peripheral immune system were thought to operate independently.”
“However, new research has led to important advances in our understanding of how immune-related events in the periphery can influence CNS processes, thereby altering cognition, mood, and behavior, and these advances are suggesting that inflammation may have important long term implications for the brain.”
“Inflammation in the body can lead to inflammation in the brain”
“The same cytokines that participate in producing the inflammatory response in the body also initiate the communication process to the CNS. They accumulate in the bloodstream and thereby travel to the brain”
“They cross into the brain in regions where the barrier is weak, and they bind to receptors on the insides of the cerebral vascular blood vessels, thereby inducing the production of soluble mediators within the epithelial cells that can cross into the brain.”
“In addition, there are neural as well as blood-borne communication routes. For example, there are cytokine receptors on nerves, such as the vagus, that innervate peripheral immune organs, and these nerves communicate to the brain and are activated during infection.”
“During a normal infection, neuroinflammation and the resulting adaptive sickness behaviors persist only for several days. However, if these responses become exaggerated or prolonged, the outcomes may well become established, leading to cognitive impairment instead of brief memory disruption,”
“… physiology can become pathology when a set of processes designed to be relatively brief becomes prolonged.”
“However, peripheral inflammation is highly complex and involves many immune cells and their products. Existing anti-inflammatory drugs often target only one of these. For example, non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, inhibit only a hormone, prostaglandins, leaving other actors in inflammation (cytokines, chemokines, etc.) untouched.”
“A second way that central neuroinflammation could be prolonged is less obvious. The CNS may come to over-respond to the same signal from the peripheral immune system. As noted above, microglia and the cytokines they produce when activated are at the core of the neuroinflammatory response that produces sickness behaviors. If microglia were to become “sensitized,” which means they respond in exaggerated or prolonged fashion, then sickness behaviors would become intensified and prolonged—pathology instead of physiology.”
“Most encouragingly, studies in numerous animal models show that the development and expression of chronic pain can be blocked with drugs that inhibit either microglial activation within the spinal cord, or the inflammatory cytokines that microglia produce.”
“In addition, microglia also can become sensitized without a prolonged peripheral inflammation. For example, aging appears to sensitize microglia so that microglia, particularly in the hippocampus, respond in exaggerated fashion to input. Thus, neuroinflammation produced by surgery, peripheral infection, and the like, is greatly exaggerated in aged subjects. Correspondingly, aging also augments the chances of depressive behaviors, cognitive impairments, and pain produced by peripheral inflammatory events. Encouragingly, however, some human studies show that inhibition of microglia and cytokines in the brain blunts such pathological outcomes.”
“Blockade of inflammation in the periphery and microglial activation/cytokine action in the CNS, may well become important therapies for a range of disorders not often thought of as mediated by these factors.”
ConclusionThere is nothing new to me in the Dana paper; this in itself is rather a shock. If you have followed my blog from the start, you should also not be surprised; but I have never seen quite so much scientific good sense written in just four pages. It tells me a lot and reassures me that I am on the right track with my cytokine blocking therapies, mast cell stabilization and somewhat far fetched, vagus nerve stimmulation ideas.
There are other science-based "inflammation control" therapies and I will be writing about them later.
P.S. Why no Dean’s List for Martha?Regular readers of my blog may have noticed that a small number of the several hundred researchers, whose papers are discussed here, are given a pat on the back and moved to the Dean’s List. Why not Martha?
There is a good reason. For many years Martha keeps going on about the “Fever Effect” in autism. This is the strange phenomenon where autistic behaviours abate during fever, i.e. sickness associated with high temperature. I myself witness this every time Monty, aged 10 with ASD, has a high temperature. I think that conclusively solving this, might indeed tell us something profound about this wide phenotype of autism.I think with the resources of Harvard, she should be able to figure this out. Her TRANSCEND Program gives her a pool of research subjects.
Peter has just one mouse model of autism and, at the age of 10, he is getting a big to be called a mouse.So Martha, put aside the MRIs and the calcium channelopathies, if you figure it out before me, you get on the Dean’s List.
If I can prove the underlying reason, I will put myself on the Dean’s List.